JPH09219832A - Image display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display the operator of which hardly gets tired by attaining clear observation in a wide angle of view, hardly generating the deterioration of the brightness of an image and attaining a small size and a light weight. SOLUTION: The image display consists of an image display element and an eyepiece optical system projecting an image formed by it to lead to observer' s eye-balls. The eye piece optical system 3 is provided with three faces and a space formed between the three faces is filled with the medium of a refractive index larger than 1. The three faces are a first face 5 being a reflection face and an internal reflection face, a second face 6 being a reflection face which opposes to the first face 5 and is eccentric or tilted with respect to an observer's visual line, and the third face 7 being the reflection face closest to the image display element 4 in the order of the passing of a light beam according to the tacking of a back light beam from the observer's eye-ball to the image display element 4. Then the number of reflecting times is three from the observer's eye-ball to the image display element 4.

Description

Detailed Description of the Invention

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image display device, and more particularly to a head or face-mounted image display device capable of being held on the head or face of an observer.

[0002]

2. Description of the Related Art As a conventional well-known head- or face-mounted image display device, there is JP-A-3-101709. As shown in the optical system in FIG. 20, in this image display device, the display image of the image display element is transmitted as an aerial image by a relay optical system including a positive lens, and the aerial image is transmitted by an eyepiece optical system including a concave reflecting mirror. Is magnified and projected in the eyeball of the observer.

Another conventional type of image display device is disclosed in Japanese Patent Laid-Open No. 214782/1987. As shown in FIGS. 21 (a) and 21 (b), this apparatus is an apparatus in which an image display element is magnified by an eyepiece lens and can be directly observed.

Further, another conventional type of image display device is disclosed in US Pat. No. 4,026,641. As shown in FIG. 22, this device transmits an image of an image display element to a curved object surface by a transmission element and projects the object surface in the air by a toric reflection surface.

Another type of conventional image display device is US Pat. No. 27,356.
As shown in FIG. 23, this device is an eyepiece optical system that projects an object plane onto an exit pupil by a semitransparent concave mirror and a semitransparent plane mirror.

[0006]

However, FIG.
In the image display device of the type that relays the image of such an image display element, regardless of the format of the eyepiece optical system, several lenses must be used as a relay optical system other than the eyepiece optical system, so the optical path length is long. , The optical system becomes large and heavy.

Further, in the layout as shown in FIG. 21, the amount of projection of the device from the observer's face becomes large. Further, the image display element and the illumination optical system are attached to the protruding portion, so that the apparatus becomes larger and heavier.

The head-mounted image display device is a human body,
In particular, since the device is worn on the head, if the amount of the device protruding from the face is large, the distance from the point supported by the head to the center of gravity of the device becomes longer, and the balance when worn becomes poor. Further, there is a possibility that the apparatus may hit an object when the apparatus is mounted, moved, rotated, or the like. That is, it is important that the head-mounted image display device is small and lightweight.
A major factor that determines the size and weight of this device is the configuration of the optical system.

However, if only a normal magnifying glass is used as the eyepiece optical system, the generated aberration is very large and there is no means for correcting it. Even if spherical aberration can be corrected to some extent by making the concave surface of the magnifying glass aspherical, coma aberration, field curvature, etc. remain, so increasing the observation angle of view may be a practical device. Absent. Alternatively, when only a concave mirror is used as the eyepiece optical system, not only a normal optical element (lens or mirror) but also a transmission element (as shown in FIG. 22) having a curved surface in accordance with the generated field curvature ( A means of correcting this by means of a fiber plate) must be used.

On the other hand, as shown in FIG. 23, in the coaxial eyepiece optical system for projecting the object surface onto the observer's pupil using a semi-transmissive concave mirror and a semi-transmissive plane mirror, two semi-transmissive surfaces are used. Therefore, the brightness of the image is reduced to 1/16 even with the theoretical value. Further, since the curvature of field generated by the semi-transmissive concave mirror is corrected by bending the object surface itself, it is difficult to use a so-called flat display such as an LCD (liquid crystal display element) as an image display element.

The present invention has been made in view of such problems of the prior art, and an object of the present invention is that clear observation is possible in a wide angle of view, and a decrease in brightness of an image almost occurs. Furthermore, it is an object of the present invention to provide an image display device that is less fatigued because it is extremely small and lightweight.

[0012]

A first image device of the present invention that achieves the above-mentioned object projects an image display element for displaying an image and an image formed by the image display element, and projects the image on an eyeball of an observer. In the image display device including the guiding eyepiece optical system, the eyepiece optical system has a number of reflections of 3 times until the light beam emitted from the image display element reaches the observer's eyeball.
The number of times is an odd number of times or more, and the surface of the eyepiece optical system immediately in front of the observer's eye is a refracting surface that emits light from the eyepiece optical system while performing internal reflection.

A second image device of the present invention is an image display device comprising an image display element for displaying an image and an eyepiece optical system for projecting the image formed by the image display element and guiding it to the observer's eyeball. In the eyepiece optical system, the number of reflections of a light beam emitted from the image display element until reaching the observer's eyeball is 3, and the surface of the eyepiece optical system immediately before the observer's eyeball is internally reflected. And a refracting surface that exits the eyepiece optical system.

A third image device of the present invention is an image display device comprising an image display element for displaying an image and an eyepiece optical system for projecting the image formed by the image display element and guiding it to the observer's eyeball. The eyepiece optical system has at least three surfaces, the space formed by the at least three surfaces is filled with a medium having a refractive index larger than 1, and reaches from the observer eyeball to the image display element. A first surface which is a refracting surface and an internal reflecting surface in the order of passage of light rays according to the reverse ray tracing, and a second surface which is a reflecting surface which is opposed to the first surface and is eccentric or inclined with respect to the observer's visual axis,
A third refraction surface closest to the image display device
It is constituted by a surface, and the number of reflections from the observer's eyeball to the image display element is three times.

A fourth image device of the present invention is an image display device comprising an image display element for displaying an image and an eyepiece optical system for projecting the image formed by the image display element and guiding it to the observer's eyeball. The eyepiece optical system has at least four surfaces, the space formed by the at least four surfaces is filled with a medium having a refractive index larger than 1, and the eyeball reaches the image display element. A first surface which is a refracting surface and an internal reflecting surface in the order of passage of light rays according to the reverse ray tracing, and a second surface which is a reflecting surface which is opposed to the first surface and is eccentric or inclined with respect to the observer's visual axis,
It is composed of a third surface which is a reflection surface facing the first surface and is adjacent to the second surface, and a fourth surface which is a refraction surface closest to the image display element. It is characterized in that the number of reflections is three before reaching the image display element.

Hereinafter, the reason why the above configuration is adopted in the present invention and the function and effect thereof will be described. In the following description, for convenience in designing the optical system, the description will be given based on the backward ray tracing that traces a ray from the observer's pupil position toward the image display element.

In the first image display apparatus of the present invention, the eyepiece optical system is an eyepiece optical system in which the number of reflections of a light beam emitted from the image display element to the observer's eye is an odd number of three or more. The surface immediately before the observer's eye is characterized by being a refracting surface that reflects internal light and emits from the eyepiece optical system, and corresponds to Examples 1 to 10 described later.

In this apparatus, the light rays emitted from the image display device are reflected three or more times inside the eyepiece optical system, so that the effect of folding the light rays becomes great, the thickness of the eyepiece optical system is suppressed to the minimum, and the size is reduced. It has succeeded in achieving weight reduction. Furthermore, by setting the number of reflections to an odd number, the image display element is arranged with the back side of the display surface facing the observer. Further, in the case of an image display element that illuminates from the rear side of the image display element such as an LCD (liquid crystal display element),
Although accessory parts such as a backlight are arranged behind the image display element, since these parts are arranged along the observer's face, they do not project forward of the eyepiece optical system. In other words, it is possible to realize a small and lightweight head-mounted image display device in which the amount of protrusion from the observer's face is extremely small in configuring the entire image display device.

Further, in this case, the surface arranged immediately in front of the observer's face is refracted and reflected on the same surface, whereby the number of surfaces constituting the eyepiece optical system can be reduced and the manufacturability can be improved. it can. Further, by setting the reflection angle in the internal reflection on the first surface to be equal to or greater than the critical angle, it is not necessary to apply a reflective coating to the first surface,
Even if the transmission and reflection areas on the first surface overlap, the image on the image display element reaches the observer's eyeball without any problem. Therefore, the eyepiece optical system can be configured compactly,
A wide viewing angle can be obtained.

In the eyepiece optical system of the second image display apparatus of the present invention, the light beam emitted from the image display element is reflected three times before reaching the observer's eyeball. The surface immediately before is a refracting surface that reflects internal light and emits from the eyepiece optical system, and corresponds to Examples 1 to 10 described later.

In this device, the light rays emitted from the image display element are reflected three times inside the eyepiece optical system, so that the effect of folding the light rays becomes great, the thickness of the eyepiece optical system is suppressed as much as possible, and the size and weight are reduced. It has succeeded in realizing this. The light ray emitted from the observer's pupil is 1
The second reflection is reflected toward the observer's face, the second time is reflected from the face side to the front side, and the third time is reflected again to the observer's face side, and reaches the image display element. It is the side, and the rear surface of the display surface can be arranged facing the observer. Therefore, for the reason described above regarding the second image display device of the present invention, it is possible to realize a head-mounted image display device in which the amount of protrusion from the observer's face is extremely small. Although the same effect can be obtained with five or more reflections, as the number of reflections increases, the distance from the image display element to the observer's pupil position becomes very long, and the optical element becomes long and large. . Furthermore, since the focal length of the eyepiece optical system becomes long, it becomes difficult to secure a wide angle of view. Therefore, a well-balanced image display device can be realized by using the eyepiece optical system that allows the image of the image display element to reach the observer's eye with three reflections.

Further, in this case, since the surface arranged immediately in front of the observer's face refracts and reflects on the same surface, the number of surfaces constituting the eyepiece optical system can be eliminated and the manufacturability can be improved. . Furthermore, by setting the reflection angle in the internal reflection on the first surface to be equal to or greater than the critical angle, it is not necessary to apply a reflective coating to the first surface.
Even if the transmission and reflection areas on the surface overlap,
The image of the image display element reaches the observer's eyeball without any problem. Therefore, the eyepiece optical system can be made compact and the observation angle of view can be widened.

In the third image display apparatus of the present invention, the eyepiece optical system has at least three surfaces, and the space formed by the at least three surfaces is filled with a medium having a refractive index larger than 1. According to the reverse ray tracing from the human eye to the image display element, the first and second surfaces, which are the refracting surface and the internal reflecting surface, are opposed to each other in the order in which the light rays pass, and are decentered or inclined with respect to the observer's visual axis. The second surface, which is the reflective surface,
It is composed of a third surface which is a refracting surface closest to the image display element, and is characterized in that the number of reflections is 3 times from the eyeball of the observer to the image display element. Examples 1 to 5 correspond.

In this device, the first eyepiece optical system is used.
The space formed by the first surface, the second surface, and the third surface is filled with a medium having a refractive index larger than 1, and the light beam emitted from the image display element is reflected three times inside the eyepiece optical system, whereby the light beam is folded. The effect was tremendous, the thickness of the eyepiece optical system was suppressed as much as possible, the size and weight were reduced, and it had a wide exit pupil diameter and a wide observation angle of view, providing a clear observation image to the observer. is there.

By filling the space formed by the first surface, the second surface and the third surface with a medium having a refractive index of greater than 1, the light rays from the pupil are refracted at the first surface,
It is possible to obtain the effect of suppressing the heights of the principal ray and the dependent rays of the off-axis rays incident on the second surface to be low. This reduces the height of the chief ray on the second surface, so that the second surface does not become large and the eyepiece optical system can be downsized. Alternatively, it is possible to widen the angle of view. Further, since the height of the dependent rays is low, it is possible to suppress the occurrence of coma aberration, especially high-order coma aberration, which occurs on the second surface.

Further, since the actual optical path length is the refractive index (for example, 1.5) times the medium having the apparent optical path length, the distance from the observer's eyeball to the eyepiece optical system or the image from the eyepiece optical system. It becomes easy to secure the distance to the display element.

Further, the observation image of the image display device is not formed by the relay optical system as an intermediate image to form a real image in the air, and the eyepiece optical system does not enlarge and project it on the eyeball, but the image display device is enlarged as it is. By projecting the image on the eyeball, the observer can observe the magnified image of the image display element as a virtual image, so that the optical system can be configured with a small number of optical elements. In addition, since the second surface, which is the reflecting surface of the eyepiece optical system, is arranged in a shape that follows the curve immediately in front of the observer's face, the amount of projection of the optical element to be formed from the face can be made extremely small, and the size is small. It is possible to realize a lightweight image display device.

Further, since the eyepiece optical system is composed of a small number of surfaces of three, mechanical design is facilitated, and there are advantages such as excellent manufacturability when processing an optical element.
An inexpensive and highly productive optical system can be realized.

In the fourth image display device of the present invention, the eyepiece optical system has at least four surfaces, and the space formed by the at least four surfaces is filled with a medium having a refractive index larger than 1. According to the reverse ray tracing from the human eye to the image display element, the first and second surfaces, which are the refracting surface and the internal reflecting surface, are opposed to each other in the order in which the light rays pass, and are decentered or inclined with respect to the observer's visual axis. The second surface, which is the reflective surface,
The third reflecting surface that faces the first surface and is adjacent to the second surface
Surface, which is a refraction surface closest to the image display element
And the number of reflections from the observer's eye to the image display element is three.
Examples 6 to 10 described later correspond to this.

Also in this case, like the third image display device,
By reflecting the light rays emitted from the image display element three times inside the eyepiece optical system, the effect of folding the light rays becomes great, the thickness of the eyepiece optical system is suppressed as much as possible, and the size and weight are reduced. Has an exit pupil diameter and a wide viewing angle,
It succeeded in providing a clear observation image to the observer.

Since the eyepiece optical system is composed of four surfaces,
Transmission and reflection are performed on the same surface only on the first surface, and other reflection,
The refraction action is performed on each independent surface, and the aberrations can be mutually corrected on the respective surfaces, which is very advantageous for aberration correction.

On the other hand, as shown in FIG. 6, even when the image display element 4 is arranged either above or on the side of the observer, the image display element 4 is obliquely forward of the adjacent fourth surface 14. By positioning it, the entire device is compact and does not interfere with the observer. In the case of the image display device of the present invention having three surfaces, the second surface reflects the light twice,
When the radius of curvature is reduced, the image display element is likely to be arranged on the viewer side. Especially when the image display device is an LCD,
The backlight, the drive substrate, and the like may overhang, which may cause the face to interfere with the device. If the radius of curvature is increased, the two reflection positions on the second surface are separated,
The second surface becomes longer. As a result, the first surface also becomes long, and the optical system itself becomes large.

On the other hand, when the eyepiece optical system is composed of four surfaces, the function of the second surface in the case of three surfaces is the second surface,
It is divided into the 4th side. Therefore, since there are two surfaces on the side opposite to the observer's face and reflected to the observer's side, it is possible to set the optical path direction after each reflection to a preferable direction without depending on the curvature of each surface. That is,
The optical system can be made compact, and the image display element 4 can be set in a favorable direction without interfering with the observer's face.

In the above, at least one of the surfaces forming the eyepiece optical system can be a flat surface. This corresponds to Examples 5 and 6 described later.

That is, by making at least one surface of the eyepiece optical system a plane, the other surface can be defined with this surface as a reference, so that the mechanical design and manufacture of the eyepiece optical system can be facilitated. As a result, the processing time can be shortened, the layout of the entire apparatus can be easily performed, and the cost can be significantly reduced.

In the third and fourth image display devices, the first
It is desirable that the internal reflection of the surface be total reflection. This corresponds to Examples 1, 2, 3, 6, 7, and 8 described later.
That is, it is very effective in terms of size and performance of the optical element that the internal reflection on the first surface is the total reflection after the reflection on the second surface. This will be described in detail below.

FIG. 14 shows an optical path diagram of the image display device according to the present invention. FIG. 14A shows an eyepiece optical system when the first surface 5 is not totally reflected, and FIG. 14B shows an eyepiece optical system when the first surface 5 is totally reflected. In each sectional view, in the drawings, 1 is the observer pupil position, 2 is the observer's visual axis, 3 is the eyepiece optical system, 4 is an image display element, and 5 is the first eyepiece optical system 3.
The surface, 6 is the second surface of the eyepiece optical system 3, and 7 is the third surface of the eyepiece optical system 3. Further, in FIG. 14A, the internal reflection region M of the first surface is mirror-coated, and the other regions are refraction regions.

The light rays emitted from the pupil 1 are the first rays of the eyepiece optical system 3.
The light is incident on the surface 5, is refracted, is reflected by the second surface 6 which is a concave mirror, and is internally reflected again by the first surface 5.
As shown in (a), if the difference between the reflection height of the upper off-axis ray U on the second surface 6 and the reflection height on the first surface 5 after being reflected by the second surface 6 is large, the eyepiece optical system 3 It becomes longer and larger. That is, the smaller the height difference between the reflection points, the smaller the size of the eyepiece optical system 3 can be made. In other words, if the eyepiece optical systems have the same size, the observation angle of view can be made wider as the difference in height between the reflection points is smaller.

However, in the eyepiece optical system of the present invention, when the difference in reflection height between the second surface 6 and the first surface 5 of the upper ray U is reduced as shown in FIG. Since the incident light is reflected above the lower light ray L, when the first surface 5 is not totally reflected, the refraction area of the first surface 5 overlaps the mirror coat area M ′, and the lower light ray L is blocked. Will end up.

If the internal reflection on the first surface 5 satisfies the condition of total reflection, it is not necessary to apply a mirror coat to the first surface 5, so that the second upper surface ray U and the upper light ray U after the reflection on the second surface 6 are not necessary. 1 side 5
Even if the lower light ray L incident on the first surface 5 interferes with each other, each light ray can perform its original action. Further, the larger the reflection angle of the second surface 6 which is a decentered reflection surface, the larger the coma aberration. However, when the first surface 5 is totally reflected, the reflection angle of the second surface 6 is changed. Since it can be reduced, the effect of suppressing the occurrence of coma on the second surface 6 can be obtained. The effects described above do not depend on the number of surfaces forming the eyepiece optical system.

Further, it is desirable that the second surface is constructed as a reflecting surface with a concave surface facing the first surface. This corresponds to Examples 1, 2, 3, 4, 6, 7, and 8 described later.
When the second surface is a reflecting surface having a concave surface facing the first surface, this surface has the main positive power of the eyepiece optical system. The chief ray diverging from the pupil at a certain angle (angle of view) can be made smaller by the second surface having power. Therefore, the size of all the surfaces from the first surface to the third surface after being reflected by the second surface can be reduced,
The entire optical system can be made compact and lightweight.

On the other hand, generally, in a concave mirror that is decentered with respect to the optical axis, coma aberration occurs due to axial and off-axis co-eccentricity.
Further, as the power of the surface increases, the amount of aberration generated also increases. However, in the eyepiece optical system of the present invention, since the light is reflected twice on the second surface, it is possible to obtain a sufficient positive power of the entire system without increasing the power of this surface itself. Therefore, it is possible to suppress the amount of aberration generated in one reflection.

Further, it is desirable that the first surface is a transmission surface and a reflection surface with a convex surface facing the second surface. This corresponds to those of Examples 1, 2, 3, 4, 7, 8 described later. The first surface is a transmitting surface and a reflecting surface having a negative power with a convex surface facing the second surface, and when the second surface has a positive power, after being reflected by the second surface, the first surface is again reflected. It becomes an effective means for correcting the coma aberration and the curvature of field generated on the second surface when the light is internally reflected by the first surface.

When the second surface is a reflecting surface having a positive power, the first surface is a surface having a negative power, so that the second surface
It is possible to correct the aberration by generating a coma aberration opposite to the inner coma aberration generated on the surface on this surface. Further, it is possible to simultaneously correct the field curvature by generating the negative field curvature on the first surface with respect to the positive field curvature generated on the second surface.

Further, in order to make the internal reflection of the first surface to be the total reflection, the reflection angles of all the light rays on the first surface are the critical angle θ _r =
The condition is that it is larger than sin ⁻¹ (1 / n) (where n is the refractive index of the medium of the optical system). For example, n
= 1.5, θ _r = 41.81 °, and a reflection angle larger than that is required. Hereinafter, description will be given with reference to FIG. FIG. 15 shows an explanatory diagram of a portion that is internally reflected by the first surface 5 after being reflected by the second surface 6. (A) of the figure shows the first surface 5
Is a concave surface toward the second surface 6, and (b) of the drawing is a case where the first surface 5 is a convex surface toward the second surface 6.

The light rays reflected by the second surface 6 are reflected downward at a certain angle. As shown in FIG. 15 (a), when the first surface 5 is a reflecting surface having a concave surface with respect to the second surface 6, the normal line S of the first surface 5 is inward with respect to the second surface. It will be the direction to go. Since the lower ray L reflected by the second surface 6 is reflected from the direction along the normal line of the first surface 5, the reflection angle γ cannot be increased on the first surface 5. That is, it is difficult to satisfy the total reflection condition for all the light rays reflected by the first surface 5. On the contrary, as shown in FIG.
Is convex with respect to the second surface 6, the normal line S ′ of the first surface 5 diverges outward with respect to the second surface 6, so that the lower ray Reflection angle γ'for L
It is possible to obtain an effect of increasing the
It becomes easy to satisfy the condition of total internal reflection.

Further, the first surface may be a flat transmission surface and a reflection surface. This configuration corresponds to that of Example 6 described later. By making the first surface a flat surface, other surfaces can be defined with this surface as a reference, so that mechanical design and manufacture of the eyepiece optical system can be facilitated. by this,
The processing time can be shortened, the layout of the entire device can be easily done, and the cost can be significantly reduced. Furthermore, when observing an external image through the eyepiece optical system, an adaptive optical system for external vision is arranged outside the second surface so that the power of the entire optical system with respect to external light becomes substantially zero. However, at this time, if the first surface is a flat surface, both the entrance surface and the exit surface of the optical system are flat surfaces, so that even if the first surface is inclined, it is possible to easily view the outside world. It will be possible. Further, by joining the adaptive optical system to the second surface, a simple parallel plate is formed with respect to the external light, so that the magnification is 1 × without complete power, and the natural external environment can be observed.

Further, the internal reflection area of the first surface may be reflectively coated. This configuration corresponds to those of Examples 4, 5, 9 and 10 described later. If the internal reflection of the first surface does not satisfy the total reflection condition, it is necessary to apply a reflection coat of aluminum or the like on the area of the internal reflection of the first surface.

Further, the first surface may be a transmission surface and a reflection surface with a concave surface facing the second surface. This configuration,
The following Examples 5, 9, and 10 correspond. When the first surface has a positive power, the effect of refraction of the light rays on the first surface is great, so that the height of the light rays incident on the second surface can be made lower. By this action, it is possible to reduce the occurrence of decentering coma that occurs on the second and subsequent reflecting surfaces.

Further, the second surface may be a reflecting surface having a convex surface facing the first surface. This configuration corresponds to those of Examples 9 and 10 described later. When the first surface has positive power, the second surface has negative power, which is a necessary condition for securing the optical path length of the optical system. In the case of an eyepiece optical system with a wide angle of view as in the present invention, the optical system can be made small by providing a positive power at a position close to the exit pupil, but the first surface refracts and the second surface reflects. It is a surface that will be reflected again later. On a surface having the same curvature, the power due to reflection becomes larger than the power due to refraction. That is, the focal length becomes very short. Therefore, by applying negative power to the second surface, an appropriate focal length is obtained, and it becomes easy to arrange the image display element at a predetermined position.

The first ray in the backward ray tracing on the second surface
When the incident angle of the axial chief ray at the time of the second reflection is θ ₂ , it is desirable that 0 ° <θ ₂ <50 ° (1).

This corresponds to Examples 1 to 10 described later. In FIG. 16, in the eyepiece optical system 3 of the image display device of the present invention, the axial chief ray that exits the center of the pupil 1 and reaches the center of the image display element 4 reaches the pupil 1 of the observer from the image display element 4. And the incident angle θ ₁ set on each surface 4 to 7.
~ Θ ₅ and θ _i are shown. The sign of the angle is positive in the direction shown in FIG. 16 from the perpendicular line S at the reflection point.

This is a condition for disposing the eyepiece optical system and the image display element of the image display device of the present invention at appropriate positions. When the value becomes smaller than the lower limit of 0 ° in the above formula (1), the light ray after the reflection on the second surface returns to the observer as it is, making it impossible to observe. On the other hand, when the angle exceeds the upper limit of 50 °, the distance to the reflection position of the first surface increases, and the second surface also increases accordingly, which makes the optical system huge.

Further, when the incident angle of the axial chief ray at the first reflection in the backward ray tracing on the second surface is θ ₂ , 10 ° <θ ₂ <40 ° (2) Is more preferable.

This corresponds to Examples 1 to 10 described later. This is a condition for arranging the eyepiece optical system and the image display element of the image display device of the present invention at appropriate positions. When the value becomes smaller than the lower limit of 10 ° of the above formula (2), in the case of total reflection on the second surface, the incident angle of the light ray after being reflected on the second surface on the first surface satisfies the condition of the critical angle. It is no longer possible, and the light rays pass through the optical system and return to the observer, making it impossible to observe. On the other hand, when the angle becomes larger than the lower limit of 40 °, the reflection angle becomes large, so that coma aberration due to decentering that cannot be corrected on other surfaces occurs, and it becomes difficult to observe a clear image.

When the incident angle of the axial chief ray on the first surface is θ ₁ , it is desirable that -20 ° <θ ₁ <40 ° (3).

This corresponds to Examples 1 to 10 described later. This is a condition for disposing the eyepiece optical system of the image display device of the present invention at an appropriate position or an appropriate angle. If the value becomes smaller than the lower limit of −20 ° of the above formula (3), the eyepiece optical system falls down to the observer side, and there is a possibility that the device and the head interfere with each other. On the other hand, if it exceeds the upper limit of 40 ° and becomes large, the eyepiece optical system protrudes forward, resulting in a device with poor weight balance.

Further, when the incident angle of the axial chief ray on the first surface is θ ₁ , it is more preferable that -10 ° <θ ₁ <25 ° (4).

This corresponds to Examples 1 to 10 described later. This is a condition for disposing the eyepiece optical system of the image display device of the present invention at an appropriate position or an appropriate angle. When the value becomes smaller than the lower limit of −10 ° of the above formula (4), the eyepiece optical system falls down to the observer side, which may cause the device and the head to interfere. On the other hand, when it exceeds the upper limit of 25 °, the chromatic aberration generated on the first surface increases. In particular, off-axis chromatic aberration of magnification appears remarkably, and it becomes difficult to observe a clear image.

When the incident angle of the axial chief ray in the internal reflection of the first surface is θ ₃ , it is desirable that 20 ° <θ ₃ <70 ° (5).

This corresponds to Examples 1 to 10 described later. This is a condition for making the eyepiece optical system of the image display device of the present invention observable and compact and lightweight. When the value is smaller than the lower limit of 20 ° in the above formula (5), the internal surface is internally reflected by the first surface, then returns to the second surface, and then is reflected by the first surface to return to the observer's face. 70 ° of the upper limit
If it becomes larger than, the positions reaching the second surface or the third surface (in the case of a four-sided structure) after the reflection on the first surface are very far apart, and the optical system becomes large.

Further, when the incident angle of the axial chief ray in the internal reflection on the first surface is θ ₃ , it is more preferable that 30 ° <θ ₃ <55 ° (6).

This corresponds to Examples 1 to 10 described later. This is a condition for making the eyepiece optical system of the image display device of the present invention observable and small and lightweight. When the value becomes smaller than the lower limit of 30 ° of the above formula (6), it becomes difficult to satisfy the critical angle on this surface, and it becomes impossible to observe. On the contrary, if it becomes larger than the upper limit of 55 °, the first
After the light is reflected by the surface, the positions reaching the second surface or the third surface (in the case of the four-surface configuration) are separated, and the optical system becomes large.

The incident angle of the axial chief ray at the second reflection in the backward ray tracing on the second surface in the case of the three-sided structure or on the third surface in the case of the four-sided structure is θ ₄ . In this case, it is desirable that 20 ° <θ ₄ <80 ° (7).

This corresponds to Examples 1 to 10 described later. This is a condition for observing every corner of the image of the image display element by the eyepiece optical system of the image display device of the present invention. When the value becomes smaller than the lower limit of 20 ° of the above formula (7), the light ray returns to the first surface, so that the reflected light ray reaches the observer's face and becomes unobservable. On the other hand, when the value exceeds the upper limit of 80 °, the distance from the internal reflection position on the first surface becomes very long, and the optical system moves to the position shown in FIG.
At the bottom, it becomes long and becomes huge.

Further, the incident angle of the axial chief ray at the time of the second reflection in the backward ray tracing on the second surface in the case of the three-side structure or on the third surface in the case of the four-side structure is set to θ ₄ . In this case, it is more preferable that 30 ° <θ ₄ <65 ° (8).

This corresponds to those in Examples 1 to 10 described later. This is a condition for observing the image of the image display element clearly in every corner by the eyepiece optical system of the image display device of the present invention. When the value goes below the lower limit of 30 ° in the above equation (8) and becomes smaller, the ray or pupil direction (upward in FIG. 16).
The off-axis rays interfere with the first surface on the third surface or the fourth surface (in the case of a four-surface configuration), which is the refracting surface of the eyepiece optical system, so that it is clearly visible in every corner of the screen. It becomes difficult to observe. On the other hand, if it exceeds the upper limit of 65 °, the reflection angle here becomes too large, and coma aberration occurs due to decentering that cannot be corrected by other surfaces.
It becomes difficult to observe a clear image.

The third surface in the case of a three-sided structure, or 4
The incident angle of the axial chief ray on the fourth surface in the case of the surface configuration is θ
_{When it is 5} , it is desirable that -30 ° <θ ₅ <40 ° (9).

This corresponds to those in Examples 1 to 10 described later. This is a condition for disposing the eyepiece optical system and the image display element of the image display device of the present invention at appropriate positions. When the value becomes smaller than the lower limit of −30 ° of the above expression (9), the light ray is directed in the direction opposite to the pupil direction (downward in FIG. 16).
The image display element moves away from the pupil because it refracts to
The entire device becomes large. Conversely, the upper limit of 4
When it exceeds 0 ° and becomes large, the light ray is reflected in the pupil direction (upward in FIG. 16), so that the image display element is arranged on the face side, and there is a risk of interference with the observer's face.

When the incident angle of the axial chief ray on the image display element surface is θ _i , it is desirable that -40 ° <θ _i <40 ° (10).

This corresponds to Examples 1 to 10 described later. This is a condition for observing the image of the image display element clearly in every corner by the eyepiece optical system of the image display device of the present invention. When the lower limit of −40 ° of the formula (10) is decreased or the upper limit of 40 ° is increased, the amount of light emitted from the image display device can sufficiently reach the observer's pupil. It becomes difficult to observe a bright and clear screen.

Further, when the incident angle of the axial chief ray on the image display element surface is θ _i , it is more preferable that -25 ° <θ _i <25 ° (11).

This corresponds to Examples 1 to 10 described later. This is a condition for observing the image of the image display element clearly in every corner by the eyepiece optical system of the image display device of the present invention. When the lower limit of −25 ° of the above formula (11) is exceeded or the upper limit of 25 ° is exceeded, the contrast is low when the viewing angle characteristic of the image display element is small. It becomes an image. In particular, in the case of an LCD (liquid crystal display element), since the viewing angle characteristic is small, an image inversion phenomenon occurs, and it is difficult to clearly observe the screen.

When the d-line refractive index of a medium having a refractive index greater than 1 is N _d , it is desirable that 1.45 <N _d <2.0 (12).

This corresponds to Examples 1 to 10 described later. This is a condition regarding the refractive index of the medium that fills the space formed by at least three surfaces. The eyepiece optical system of the image display device of the present invention is preferably formed of a highly transparent transparent medium called optical glass or optical plastic. In that case, the refractive index of the d-line of the medium is (1
The condition is that the formula 2) is satisfied. When the lower limit or the lower limit of the expression (12) is exceeded, the transparency becomes low and the workability becomes poor.

Further, when the d-line refractive index of the medium having a refractive index larger than 1 is N _d , it is more preferable that 1.5 <N _d <2.0 (13).

This corresponds to Examples 1 to 5 and 7 to 10 described later. The eyepiece optical system of the image display device of the present invention,
In order to satisfy the condition of internal reflection on the first surface, it is advantageous that the refractive index is as large as possible. Therefore, (1
It is desirable to use a medium that satisfies the condition of equation 3).
If the lower limit of 1.5 in the condition of the equation (13) is exceeded, especially in the case of a wide angle of view, the off-axis ray cannot satisfy the condition of total reflection on the first surface, and the peripheral image is observed. Can be difficult.

Further, at least one constituting the eyepiece optical system.
It is desirable that the two surfaces are aspherical surfaces.

This corresponds to Examples 1 to 10 described later. It is effective for aberration correction that any one of the first surface, the second surface and the third surface of the eyepiece optical system is an aspherical surface. As will be described later, the observer's iris position 1 is the origin, and the observer's visual axis 2 is orthogonal to the Z axis that is positive in the direction from the origin to the eyepiece optical system 3 and the observer's visual axis 2. In the case of defining the Y axis that is positive from the bottom to the top in the vertical direction and the X axis that is orthogonal to the observer's visual axis 2 and is positive from the right to the left in the observer's eye (see FIG. 1) , Is an important condition for correcting coma aberration generated in the second surface 6 which is eccentric in the Y direction or inclined with respect to the visual axis 2, particularly high-order coma aberration and coma flare.

As in the present invention, in an image display apparatus using an eyepiece optical system of a type having a reflecting surface which is decentered or inclined in front of the observer's eyeball, the light rays incident on the reflecting surface are oblique even on the axis. Therefore, complicated coma is generated on the central axis of the reflecting mirror. This complicated coma is
It increases as the tilt angle of the reflecting surface increases. However, in order to realize a small-sized image display device having a wide angle of view, it is difficult to secure a wide-angle observation image because the image display element and the optical path interfere with each other unless the eccentricity or the tilt angle is increased to some extent. Become. Therefore, the smaller the image display device with a wide angle of view, the larger the inclination of the reflecting surface,
How to correct the occurrence of decentering coma is an important issue.

In order to correct such a plurality of coma aberrations, any one of the first surface, the second surface, and the third surface of the eyepiece optical system is made an eccentric aspherical surface, and The power of the system can be made asymmetric with respect to the visual axis, and the effect of the aspherical surface can be used off-axis, so that the coma aberration including on-axis can be effectively corrected. Is possible.

At least one component of the eyepiece optical system
It is desirable that the two surfaces are anamorphic surfaces.

This corresponds to Examples 1 to 10 described later. It is important that any one of the first surface, the second surface and the third surface of the eyepiece optical system is an anamorphic surface. That is, the radius of curvature in the YZ plane and XZ which is orthogonal to this plane.
That is, the surfaces have different in-plane radii of curvature.

This condition is a condition for correcting an aberration caused by the eccentricity or inclination of the second surface with respect to the visual axis. In general, when the spherical surface is decentered, the light ray incident on the surface has different curvatures with respect to the light ray in the plane of incidence and the plane orthogonal to the plane of incidence. Therefore, as in the present invention, in the eyepiece optical system in which the reflecting surface is arranged eccentric or inclined with respect to the visual axis in front of the observer's eyeball, the observation image on the visual axis corresponding to the observation image center is also due to the above reason. Astigmatism occurs.
In order to correct the astigmatism on this axis, the radius of curvature of any one of the first surface, the second surface, and the third surface of the eyepiece optical system is different between the incident surface and the surface orthogonal to this. It becomes important to do things.

At least one component of the eyepiece optical system
The two surfaces may be free-form surfaces. If at least one of the three surfaces forming the eyepiece optical system is a free-form surface, the effect of the aspherical surface or anamorphic surface described above can be satisfied, so that the aberration generated in the eyepiece optical system is effective. Can be corrected to.

Here, the free curved surface is a curved surface expressed by the following equation. However, x, y, and z represent Cartesian coordinates, C _nm is an arbitrary coefficient, and k and k ′ are also arbitrary.

Further, it is desirable that the display surface of the image display element is arranged so as to be inclined with respect to the axial principal ray.

This corresponds to Examples 1 to 10 described later. It is important that the display surface of the image display element is arranged so as to be inclined with respect to the visual axis. When the refracting surface or the reflecting surface forming the optical element is decentered or tilted, the light ray from the pupil has a refraction angle or a reflection angle depending on the image height on the refraction surface or the reflection surface, and the image surface is tilted with respect to the visual axis. Sometimes. In that case, it is possible to correct the tilt of the image plane by disposing the image display element surface so as to be tilted with respect to the visual axis.

Further, it is desirable that the image display element is arranged with the back side of the display surface of the image display element facing the observer.

This corresponds to Examples 1 to 10 described later. It is effective to make the entire device compact in that the image display element is arranged on the observer side toward the back side of the display surface. When the image display element is of a type in which a backlight or the like is attached to the back of the display element, these parts are arranged along the observer's face, so there is nothing that projects forward of the eyepiece optical system. . In other words, it is possible to realize the one in which the amount of protrusion from the observer's face is extremely small in configuring the entire image display device.

By providing a means for positioning the image display element and the eyepiece optical system with respect to the observer's head,
The observer can observe a stable observation image.

Further, the image display device and the eyepiece optical system have a positioning means with respect to the observer's head and can be mounted on the observer's head, so that the observer can freely observe the posture and direction. It is possible to observe the image.

Further, by having the supporting means for supporting at least two sets of the image display device of the present invention at regular intervals, the observer can enjoy a stereoscopic image by observing them with both left and right eyes. Become.

Furthermore, by constructing the image display surface in the eyepiece optical system as an image plane so as to form an image of an object at infinity, as will be described later, such as a finder optical system of a camera as shown in FIG. It can be used as an imaging optical system.

[0095]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments 1 to 10 of an image display device of the present invention will be described below with reference to the drawings.
Although constituent parameters of each example will be described later, in the following description, the surface numbers are from the pupil position 1 of the observer to the eyepiece optical system 3.
It is shown as the face number of the reverse trace towards. Then, as shown in FIG. 1, the coordinates are taken in such a manner that the observer's iris position 1 is the origin, and the observer's visual axis 2 is the Z axis in which the direction from the origin to the eyepiece optical system 3 is positive. A Y-axis that is orthogonal to the axis 2 and that is positive from the bottom to the top in the vertical direction when viewed from the observer's eye, and a axis that is orthogonal to the observer's visual axis 2 and that is positive from the right to the left in the left-right direction when viewed from the observer's eye Define as an axis. That is, FIG.
The inside of the paper is the YZ plane, and the plane perpendicular to the paper is XZ
Face. It is assumed that the optical axis is bent in the YZ plane of the drawing.

Then, in the constituent parameters described later, regarding the surface on which the eccentricity amounts Y and Z and the tilt angle θ are described, the Y of the surface apex from the one surface (pupil position 1) which is the reference surface. It means the amount of eccentricity in the axial direction, the Z-axis direction, and the angle of inclination of the central axis of the surface from the Z-axis, and in this case, θ means counterclockwise. It should be noted that the distance between the surfaces has no meaning.

Further, in each surface, an aspherical shape which is non-rotationally symmetric has coordinates R _y and R _{x which} are paraxial curvature radii in the YZ plane (paper surface) and X- Paraxial radii of curvature in the Z plane, K _x and K _y are the X-Z plane and Y-, respectively.
The conic coefficients AR and BR in the Z plane are the fourth-order and sixth-order aspherical coefficients rotationally symmetric with respect to the Z axis, respectively, and AP and BP are the fourth-order and sixth-order non-spherical coefficients rotationally asymmetric with respect to the Z axis, respectively. Assuming a spherical coefficient, the aspherical expression is as shown below.

Z = [(X ² / R _x ) + (Y ² / R _y )] / [1+
｛1- (1 + K _x ) (X ² / R _x ² )-(1 + K _y ) (Y ² / R _y ² )｝
^{1/2] + AR [(1-} AP) X 2 + (1 + AP) Y 2] 2 + B
R [(1-BP) X 2 + (1 + BP) Y 2] 3 The refractive index of the medium between the surfaces is expressed by the refractive index of the d-line. The unit of the length is mm.

1 to 10 are sectional views of the monocular image display devices of Examples 1 to 10, respectively. In each of the sectional views of FIGS. 1 to 5, 1 is the pupil position of the observer,
2 is an observer's visual axis, 3 is an eyepiece optical system, 4 is an image display element,
5 is the first surface of the eyepiece optical system 3, and 6 is the second surface of the eyepiece optical system 3.
Surface 7, is the third surface of the eyepiece optical system 3.

In each of the sectional views of FIGS. 6 to 10, 1 is the position of the observer's pupil, 2 is the observer's visual axis, 3 is an eyepiece optical system, 4 is an image display element, and 11 is an eyepiece optical system. 3 is a first surface, 12 is a second surface of the eyepiece optical system 3, 13 is a third surface of the eyepiece optical system 3, and 14 is a fourth surface of the eyepiece optical system 3.

The actual ray paths in these examples are as follows. In Examples 1 to 5, the ray bundle emitted from the image display element 4 is refracted by the third surface 7 of the eyepiece optical system 3 to be reflected. , Is reflected by the second surface 6, is internally reflected by the first surface 5, is reflected again by the second surface 6, is incident on the first surface 5, is refracted, and exits the eyepiece optical system 3, The iris position of the observer's pupil or the center of rotation of the eyeball is projected into the observer's eyeball as the exit pupil l.

In Examples 6 to 10, the ray bundle emitted from the image display element 4 is refracted by the fourth surface 14 of the eyepiece optical system 3, enters the eyepiece optical system 3, and is reflected by the third surface 13. Internal reflection on the first surface 11 and reflection on the second surface 12,
The light is incident on the first surface 11 and is refracted to be emitted from the eyepiece optical system 3, and is projected into the eyeball of the observer as the exit pupil 1 at the iris position of the observer's pupil or the center of rotation of the eyeball.

The embodiment shown below is an image device for the right eye, and for the left eye, it can be realized by structuring all the constituent optical elements in the YZ plane. Also, in the actual arrangement of the device, it goes without saying that the direction reflected by the eyepiece optical system may be above the observer or in the lateral direction.

The angle of view, the pupil diameter, the surface shape of each surface, the incident angle of each surface, and the refractive index of the transparent medium in each embodiment will be described below. Example 1 is an example of an eyepiece optical system having a three-sided structure as shown in the sectional view of FIG.
2.8 °, pupil diameter 4 mm, first surface (surface numbers 2, 4) 5, second surface (surface numbers 3, 5) 6, and third surface (surface number 6) 7 are all anamorphic surfaces. The internal reflection of the first surface 5 is total reflection. The values relating to the conditional expressions (1) to (13) are θ ₁ = 11.14 ° θ ₂ = 22.64 ° θ ₃ = 41.71 ° θ ₄ = 48.13 ° θ ₅ = 6.53 ° θ _i = 30.00 ° N _d = 1.6481.

The second embodiment is the same as that shown in the sectional view of FIG.
It is an example of an eyepiece optical system having a surface configuration, and a horizontal angle of view of 30
°, vertical angle of view 22.8 °, pupil diameter 4 mm, first surface (surface numbers 2 and 4) 5, second surface (surface numbers 3 and 5) 6 are anamorphic surfaces, and third surface (surface number 6) ) 7 is a spherical surface. First
The internal reflection of the surface 5 is total internal reflection. Conditional expressions (1) to (1
The value of 3) is θ ₁ = 10.68 ° θ ₂ = 24.93 ° θ ₃ = 46.20 ° θ ₄ = 55.63 ° θ ₅ = 7.30 ° θ _i = 30.00 ° N _d = 1.5163.

In the third embodiment, as shown in the sectional view of FIG.
It is an example of an eyepiece optical system having a surface configuration, and a horizontal angle of view of 30
°, vertical angle of view 22.8 °, pupil diameter 4 mm, first surface (surface numbers 2 and 4) 5, second surface (surface numbers 3 and 5) 6 are anamorphic surfaces, and third surface (surface number 6) ) 7 is a spherical surface. First
The internal reflection of the surface 5 is total internal reflection. Conditional expressions (1) to (1
The value for 3) is θ ₁ = 1.78 ° θ ₂ = 18.45 ° θ ₃ = 40.59 ° θ ₄ = 38.85 ° θ ₅ = −7.49 ° θ _i = 30.09 ° N _d = 1.7433.

In the fourth embodiment, as shown in the sectional view of FIG.
It is an example of an eyepiece optical system having a surface configuration, and a horizontal angle of view 28
°, vertical angle of view 21.2 °, pupil diameter 4 mm, first surface (surface numbers 2 and 4) 5, second surface (surface numbers 3 and 5) 6 are anamorphic surfaces, and third surface (surface number 6) ) 7 is a spherical surface. First
The internal reflection of the surface 5 is due to the mirror coating. The values relating to the conditional expressions (1) to (13) are as follows: θ ₁ = 14.75 ° θ ₂ = 25.72 ° θ ₃ = 44.37 ° θ ₄ = 48.25 ° θ ₅ = −3.61 ° θ _i = 23.58 ° N _d = 1.5163.

In the fifth embodiment, as shown in the sectional view of FIG.
It is an example of an eyepiece optical system having a surface configuration, and a horizontal angle of view 28
°, vertical angle of view 21.2 °, pupil diameter 4 mm, first surface (surface numbers 2 and 4) 5 is an anamorphic surface, second surface (surface numbers 3 and 5) 6 is a flat surface, and third surface (Surface number 6) 7 is a spherical surface. The inner surface reflection of the first surface 5 is due to mirror coating. The values relating to the conditional expressions (1) to (13) are θ ₁ = 21.92 ° θ ₂ = 29.66 ° θ ₃ = 37.39 ° θ ₄ = 45.13 ° θ ₅ = −2.36 ° θ _i = 23.58 ° N _d = 1.5163.

In the sixth embodiment, as shown in the sectional view of FIG.
It is an example of an eyepiece optical system having a surface configuration, and a horizontal angle of view of 30
°, vertical angle of view 22.8 °, pupil diameter 4 mm, first surface (surface number 2, 4) 11 is a plane, second surface (surface number 3) 12,
The third surface (surface number 5) 13 and the fourth surface (surface number 6) 14 are anamorphic surfaces. The internal reflection of the first surface 11 is total reflection. The values relating to the conditional expressions (1) to (13) are θ ₁ = 7.7 ° θ ₂ = 25.23 ° θ ₃ = 45.29 ° θ ₄ = 48.31 ° θ ₅ = 0.76 ° θ _i = 14.41 ° N _d = 1.4870.

In the seventh embodiment, as shown in the sectional view of FIG.
It is an example of an eyepiece optical system having a surface configuration, and a horizontal angle of view of 30
°, vertical angle of view 22.8 °, pupil diameter 4 mm, first surface (surface number 2, 4) 11 is a spherical surface, second surface (surface number 3) 12,
The third surface (surface number 5) 13 is an anamorphic surface, and the fourth surface (surface number 6) 14 is a spherical surface. The internal reflection of the first surface 11 is total reflection. The values relating to the conditional expressions (1) to (13) are θ ₁ = 1.81 θ ₂ = 20.61 ° θ ₃ = 43.42 ° θ ₄ = 43.88 ° θ ₅ = 0.28 ° θ _i = 17.20 ° N _d = 1.5163.

In the eighth embodiment, as shown in the sectional view of FIG.
It is an example of an eyepiece optical system having a surface configuration, and a horizontal angle of view of 40
°, vertical angle of view 30.6 °, pupil diameter 4 mm, first surface (surface number 2, 4) 11, second surface (surface number 3) 12, third surface (surface number 5) 13, fourth surface ( Surface number 6) 14 are anamorphic surfaces. The internal reflection of the first surface 11 is total reflection. The values relating to the conditional expressions (1) to (13) are θ ₁ = 1.28 θ ₂ = 23.53 ° θ ₃ = 49.91 ° θ ₄ = 41.12 ° θ ₅ = 9.02 ° θ _i = 10.85 ° N _d = 1.5338.

In the ninth embodiment, as shown in the sectional view of FIG.
It is an example of an eyepiece optical system having a surface configuration, and a horizontal angle of view of 30
°, vertical angle of view 22.6 °, pupil diameter 4 mm, first surface (surface number 2, 4) 11 is a spherical surface, second surface (surface number 3) 12,
The third surface (surface number 5) 13 is an anamorphic surface, and the fourth surface (surface number 6) 14 is a spherical surface. The internal reflection of the first surface 11 is due to mirror coating. Conditional expressions (1) to (1
The value for 3) is θ ₁ = 10.90 θ ₂ = 30.73 ° θ ₃ = 34.05 ° θ ₄ = 53.95 ° θ ₅ = −6.61 ° θ _i = 23.58 ° N _d = 1.5163.

The tenth embodiment is an example of an eyepiece optical system having a four-sided structure as shown in the sectional view of FIG.
8 °, vertical angle of view 21.2 °, pupil diameter 4 mm, first surface (surface numbers 2 and 4) 11 is a spherical surface, and second surface (surface number 3) 1
The second and third surfaces (surface number 5) 13 are anamorphic surfaces, and the fourth surface (surface number 6) 14 is a spherical surface. First side 11
The internal reflection of is due to mirror coating. Conditional expression (1)
The values relating to (13) are as follows: θ ₁ = 22.80 θ ₂ = 32.25 ° θ ₃ = 30.96 ° θ ₄ = 35.41 ° θ ₅ = −4.20 ° θ _i = 23.58 ° it is a N _d = 1.5163.

The values of the constituent parameters in the backward ray tracing of Examples 1 to 10 are shown below.

Example 1 Surface number Curvature radius Spacing Refractive index Abbe number (eccentricity) (tilt angle) 1 ∞ (pupil) 2 R _y -210.566 1.6481 55.28 R _x -616.660 Y -26.631 θ 34.36 ° K _y 0 Z 3.827 K _x 0 AR 0 BR 0 AP 0 BP 0 3 R _y -130.170 1.6481 55.28 R _x -131.141 Y 41.547 θ 10.87 ° K _y 0 Z 50.217 K _x 0 AR -2.8856 × 10 ^-10 BR -2.3366 × 10 ^-15 AP -4.1410 BP 5.4988 4 R _y -210.566 1.6481 55.28 R _x -616.660 Y -26.631 θ 34.36 ° K _y 0 Z 3.827 K _x 0 AR 0 BR 0 AP 0 BP 0 5 R _y -130.170 1.6481 55.28 R _x -131.141 Y 41.547 θ 10.87 ° K _y 0 Z 50.217 K _x 0 AR -2.8856 × 10 ^-10 BR -2.3366 × 10 ^-15 AP -4.1410 BP 5.4988 6 R _y -139.371 Y -39.978 θ 49.40 ° R _x 339.330 Z 67.618 K _y 0 K _x 0 AR 0 BR 0 AP 0 BP 0 7 (image display device) Y −46.520 θ 28.24 ° Z 41.317.

Example 2 Surface number Curvature radius Spacing Refractive index Abbe number (Eccentricity) (Inclination angle) 1 ∞ (Pupil) 2 R _y -161.656 1.5163 64.15 R _x -1301.410 Y 3.977 θ 26.73 ° K _y 0 Z 12.107 K ^{_{x 0 AR 1.9502 × 10 -7 BR}} -1.0740 × 10 -11 AP 1.1334 BP 2.0740 3 R y -136.884 1.5163 64.15 R x -147.084 Y 4.315 θ 35.86 ° K y -0.4474 Z 30.348 K x -1.1088 AR 5.6195 × 10 - ⁸ BR -8.8973 × 10 ^-15 AP 2.6626 × 10 ^-1 BP 7.2753 4 R _y -161.656 1.5163 64.15 R _x -1301.410 Y 3.977 θ 26.73 ° K _y 0 Z 12.107 K _x 0 AR 1.9502 × 10 ^-7 BR -1.0740 × 10 ^-11 AP 1.1334 BP 2.0740 5 R _y -136.884 1.5163 64.15 R _x -147.084 Y 4.315 θ 35.86 ° K _y -0.4474 Z 30.348 K _x -1.1088 AR 5.6195 × 10 ^-8 BR -8.8973 × 10 ^-15 AP 2.6626 × 10 ^-1 BP 7.2753 6 192.794 Y -47.076 θ 79.13 ° Z 41.366 7 (image display device) Y -56.120 θ 38.58 ° Z 39.788.

Example 3 Surface number Curvature radius Spacing Refractive index Abbe number (amount of eccentricity) (tilt angle) 1 ∞ (pupil) 2 R _y -51.348 1.7433 44.75 R _x -45.397 Y -8.790 θ 29.67 ° K _y -0.0909 Z 1.764 K _x 1.6087 AR -2.7583 × 10 ^-8 BR -2.8974 × 10 ^-10 AP -2.4093 BP 1.9705 3 R _y -57.489 1.7433 44.75 R _x -53.053 Y 15.378 θ 32.14 ° K _y -0.1177 Z 40.450 K _x 0.1510 AR- 5.1413 × 10 ^-9 BR 4.8987 × 10 ^-11 AP -7.1903 BP -4.2086 × 10 ^-1 4 R _y -51.348 1.7433 44.75 R _x -45.397 Y -8.790 θ 29.67 ° K _y -0.0909 Z 1.764 K _x 1.6087 AR -2.7583 × 10 ^-8 BR -2.8974 × 10 ^-10 AP -2.4093 BP 1.9705 5 R _y -57.489 1.7433 44.75 R _x -53.053 Y 15.378 θ 32.14 ° K _y -0.1177 Z 40.450 K _x 0.1510 AR -5.1413 × 10 ^-9 BR 4.8987 × 10 ^-11 AP -7.1903 BP -4.2086 × 10 ^-1 6 -17.021 Y -21.771 θ 72.83 ° Z 27.458 7 (image display device) Y -35.479 θ 14.03 ° Z 30.627.

Example 4 Surface Number Curvature Radius Spacing Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (Pupil) 2 R _y -408.985 1.5163 64.15 R _x -283.326 Y -14.922 θ 24.30 ° K _y 0 Z 12.616 K _x 0 AR -6.5368 × 10 ^-8 BR 2.6628 × 10 ^-11 AP -4.2799 × 10 ^-2 BP 1.0453 3 R _y -137.122 1.5163 64.15 R _x -109.735 Y 5.062 θ 35.80 ° K _y -3.3707 Z 32.532 K _x- 2.6799 AR 9.0123 × 10 ^-8 BR 5.8457 × 10 ^-14 AP -3.5746 × 10 ^-2 BP -9.1012 4 R _y -408.985 1.5163 64.15 R _x -283.326 Y -14.922 θ 24.30 ° K _y 0 Z 12.616 K _x 0 AR- 6.5368 × 10 ^-8 BR 2.6628 × 10 ^-11 AP -4.2799 × 10 ^-2 BP 1.0453 5 R _y -137.122 1.5163 64.15 R _x -109.735 Y 5.062 θ 35.80 ° K _y -3.3707 7 Z 32.532 K _x -2.6799 AR 9.0123 × 10 ^-8 BR 5.8457 × 10 ^-14 AP -3.5746 × 10 ^-2 BP -9.1012 6 39.708 Y -49.190 θ 66.30 ° Z 52.374 7 (image display element) Y -50.195 θ 42.57 ° Z 47.677.

Example 5 Surface Number Curvature Radius Spacing Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (Pupil) 2 R _y 155.857 1.5163 64.15 R _x 108.364 Y -20.000 θ 30.81 ° K _y 0 Z 30.000 K _x 0 AR -1.1508 × 10 ^-7 BR 1.1468 × 10 ^-10 AP -1.3330 BP -1.7019 3 ∞ 1.5163 64.15 Y -1.565 θ 37.32 ° Z 42.461 4 R _y 155.857 1.5163 64.15 R _x 108.364 Y -20.000 θ 30.81 ° K _y 0 Z 30.000 K _x 0 AR -1.1508 × 10 ^-7 BR 1.1468 × 10 ^-10 AP -1.3330 BP -1.7019 5 ∞ 1.5163 64.15 Y -1.565 θ 37.32 ° Z 42.461 6 70.244 Y -33.253 θ 62.66 ° Z 36.315 7 (Image display Element) Y -44.749 θ 60.09 ° Z 55.961.

Example 6 Surface number Curvature radius Spacing Refractive index Abbe number (Eccentricity) (Tilt angle) 1 ∞ (pupil) 2 ∞ 1.4870 70.40 Y 0.000 θ 7.70 ° Z 33.232 3 R _y -92.681 1.4870 70.40 R _x -91.368 Y 10.225 θ 37.34 ° K _y 2.9442 Z 34.669 K _x -6.4492 AR 6.7868 × 10 ^-9 BR 1.2064 × 10 ^-12 AP 1.1032 × 10 BP -3.6642 4 ∞ 1.4870 70.40 Y 0.000 θ 7.70 ° Z 33.232 5 R _y -227.431 1.4870 70.40 R _x -73.582 Y 30.000 θ 48.36 ° K _y 0 Z 2.395 K _x 0 AR 4.6395 × 10 ^-7 BR 1.1004 × 10 ^-11 AP 5.1263 × 10 ^-1 BP -3.0762 6 R _y 66.981 R _x 16.415 Y -36.765 θ 57.28 ° K _y 0 Z 69.400 K _x 0 AR 2.2637 × 10 ^-6 BR -7.3017 × 10 ^-8 AP -3.7748 × 10 ^-1 BP -6.6901 × 10 ^-1 7 (image display element) Y -33.673 θ 45.00 ° Z 44.201.

Example 7 Surface Number Curvature Radius Spacing Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (Pupil) 2 -542.306 1.5163 64.15 Y 70.778 θ 5.68 ° Z 30.533 3 R _y -105.705 1.5163 64.15 R _x- 89.941 Y 10.014 θ 39.19 ° K _y -0.1753 Z 25.954 K _x -0.8315 AR 3.6313 × 10 ^-9 BR 6.1440 × 10 ^-18 AP -8.7199 × 10 ^-2 BP -5.0996 × 10 4 -542.306 1.5163 64.15 Y 70.778 θ 5.68 ° Z 30.533 5 R _y -180.609 1.5163 64.15 R _x -1143.935 Y 40.198 θ 41.35 ° K _y 0.1463 Z 16.177 K _x -1488.0941 AR 2.0564 × 10 ^-8 BR 5.2529 × 10 ^-14 AP -3.7942 × 10 ^-2 BP 3.6207 6- 74.701 Y -39.077 θ 34.94 ° Z 47.282 7 (Image display element) Y -36.693 θ 24.18 ° Z 36.463.

Example 8 Surface number Curvature radius Spacing Refractive index Abbe number (Eccentricity) (Tilt angle) 1 ∞ (Pupil) 2 R _y -245.203 1.5338 65.89 R _x -52.851 Y 0.000 θ 20.00 ° K _y 0 Z -1.281 K _x 0 AR 0 BR 0 AP 0 BP 0 3 R _y -59.102 1.5338 65.89 R _x -45.130 Y 15.989 θ 17.99 ° K _y -0.9559 Z 40.072 K _x -0.2970 AR 6.4446 × 10 ^-9 BR 9.3898 × 10 ^-14 AP 7.4590 BP -1.3817 × 10 4 R _y -245.203 1.5338 65.89 R _x -52.851 Y 0.000 θ 20.00 ° K _y 0 Z -1.281 K _x 0 AR 0 BR 0 AP 0 BP 0 5 R _y -92.593 1.5338 65.89 R _x -71.241 Y 29.319 θ 41.82 ° K _y 0 Z -4.482 K _x 0 AR 7.6834 × 10 ^-7 BR 1.6178 × 10 ^-11 AP 4.2887 × 10 ^-1 BP -3.0887 6 R _y -72.841 Y -28.655 θ 22.75 ° R _x 81.858 Z 36.867 K _y 0 K _x 0 AR 6.7391 × 10 ^-7 BR -4.2424 × 10 ^-10 AP -1.1564 × 10 BP -8.0054 7 (image display device) Y -28.600 θ 35.00 ° Z 19.053.

Example 9 Surface number Curvature radius Spacing Refractive index Abbe number (Decentering amount) (Inclination angle) 1 ∞ (Pupil) 2 64.328 1.5163 64.15 Y -20.000 θ 30.00 ° Z 27.699 3 R _y 139.632 1.5163 64.15 R _x 277.392 Y 0.129 θ 39.41 ° K _y -10.6785 Z 35.000 K _x 20.0000 AR -7.5208 × 10 ^-9 BR 9.3767 × 10 ^-13 AP 3.6868 BP -6.5396 4 64.328 1.5163 64.15 Y -20.000 θ 30.00 ° Z 27.699 5 R _y 61.956 1.5163 64.15 R _x 70.808 Y -2.352 θ 36.43 ° K _y 0 Z 27.385 K 0 AR 3.5927 × 10 ^-7 BR -4.9429 × 10 ^-10 AP -1.7527 BP -9.8564 × 10 ^-2 6 45.850 Y -33.382 θ 72.85 ° Z 36.018 7 ( Image display device) Y -38.077 θ 84.87 ° Z 57.285.

Example 10 Surface number Curvature radius Spacing Refractive index Abbe number (Eccentricity) (Inclination angle) 1 ∞ (Pupil) 2 68.114 1.5163 64.15 Y -7.666 θ 30.00 ° Z 24.886 3 R _y 172.006 1.5163 64.15 R _x 270.352 Y 3.180 θ 39.16 ° K _y 20.0000 Z 40.000 K _x -20.0000 AR 1.9117 × 10 ^-6 BR -8.7696 × 10 ^-10 AP -7.5555 × 10 ^-1 BP -1.2220 4 68.114 1.5163 64.15 Y -7.666 θ 30.00 ° Z 24.886 5 R _{y -150.750 1.5163 64.15 R x -87.182 Y} 20.418 θ 31.28 ° K y -79.4956 Z 32.891 K x -334.5455 AR 8.5541 × 10 -7 BR -1.7073 × 10 -10 AP 4.0595 × 10 -1 BP 8.1476 × 10 -2 6 45.311 Y -30.000 θ 67.19 ° Z 44.886 7 (Image display element) Y -36.353 θ 60.00 ° Z 51.966.

Lateral aberrations of Example 1 among Examples 1 to 10 are shown in FIGS. 11 to 13. In these lateral aberration diagrams, the numbers in parentheses represent (horizontal angle of view, vertical angle of view), and the lateral aberration at that angle of view.

Although the anamorphic surface, the spherical surface, and the flat surface are used in the above embodiments, these surfaces may be other toric surfaces, such as the rotationally symmetric aspherical surface, the spherical surface, and the expression (14). It goes without saying that it can be configured with a surface shape such as a free curved surface. Also, it goes without saying that it can be configured on the holographic side.

Further, in the case of a shape in which the curvature, power, etc. of the surface cannot be defined, the shape of the surface of the portion where the axial light ray and the surface hit along the axial light ray which advances on the visual axis and reaches the image display element. The curvature and power can also be obtained by setting the curvature within a certain arbitrary region obtained by the differential value of as the curvature of the surface.

By using the eyepiece optical system according to the present invention as described above, a pair of left and right eyepiece optical systems and an image display element are prepared, and they are supported by an eye radiation distance to support both eyes. It can be configured as a portable image display device such as a stationary image display device or a head-mounted image display device. The image display device for one eye may be configured by disposing the eyepiece optical system only for one eye.

To construct the image display device of the present invention as a head-mounted image display device (HMD) 31,
As shown in the sectional view of (a) and the perspective view of (b), for example, a headband 20 is attached and attached to the observer's head for use. In the case of this use example, the second surface 6 of the eyepiece optical system 3 is a semi-transmissive mirror (half mirror), and a see-through compensation optical system 22 and a liquid crystal shutter 21 are provided in front of this half mirror to selectively select an external image. In addition, the image of the image display element 4 can be superposed and observed. Here, the see-through compensation optical system 22 is composed of a transparent prism body set so that the power of the entire optical system with respect to the external light is set to substantially zero.

Further, when the eyepiece optical system of the image display apparatus of the present invention is used as an image forming optical system, for example, as shown in the perspective view of FIG. 18, the photographing optical system Ob and the finder optical system Fi are separated. It can be used for the finder optical system Fi of the compact camera Ca installed side by side. FIG. 19 is a block diagram of an optical system when used as such an imaging optical system.
Shown in An objective optical system Lt can be configured by the front lens group GF, the aperture stop D, and the eyepiece optical system DS according to the present invention provided behind the aperture stop D. The image formed by the objective optical system Lt is erected by the four-reflection holographic prism P provided on the observer side of the objective optical system Lt and can be observed by the eyepiece lens Oc. The image display device of the present invention has been described above based on the embodiments, but the present invention is not limited to these embodiments and various modifications can be made.

The above-described image display device of the present invention can be configured as follows, for example.

[1] An image display device for displaying an image,
In an image display device comprising an eyepiece optical system that projects an image formed by the image display element and guides it to an observer's eyeball, the eyepiece optical system includes a light beam emitted from the image display element reaching the observer eyeball. The number of reflections up to 3 times is an odd number of 3 or more, and the surface of the eyepiece optical system immediately in front of the observer's eye is a refracting surface that emits light from the eyepiece optical system while performing internal reflection. Image display device.

[2] An image display device for displaying an image,
In an image display device comprising an eyepiece optical system that projects an image formed by the image display element and guides it to an observer's eyeball, the eyepiece optical system includes a light beam emitted from the image display element reaching the observer eyeball. The image display characterized in that the number of reflections up to 3 times is three, and the surface of the eyepiece optical system immediately before the observer's eyeball is a refracting surface that internally reflects and emits the eyepiece optical system. apparatus.

[3] An image display device for displaying an image,
In an image display device comprising an eyepiece optical system that projects an image formed by the image display element and guides it to an observer's eyeball, the eyepiece optical system has at least three surfaces and is formed by the at least three surfaces. A space having a refractive index larger than 1 and a first surface, which is a refraction surface and an internal reflection surface, in the order in which the light rays pass according to the reverse ray tracing from the observer's eyeball to the image display element,
The second surface is a reflecting surface that is opposed to the first surface and is eccentric or inclined with respect to the observer's visual axis, and a third surface that is a refractive surface closest to the image display element. The image display device, wherein the number of reflections is 3 times from the eyeball of the observer to the image display element.

[4] An image display device for displaying an image,
In an image display device comprising an eyepiece optical system that projects an image formed by the image display element and guides it to an observer's eyeball, the eyepiece optical system has at least four surfaces and is formed by the at least four surfaces. A space having a refractive index larger than 1 and a first surface, which is a refraction surface and an internal reflection surface, in the order in which the light rays pass according to the reverse ray tracing from the observer's eyeball to the image display element,
A second surface, which is a reflecting surface that faces the first surface and is eccentric or inclined with respect to the observer's visual axis, and a third surface that faces the first surface and is adjacent to the second surface. And a fourth surface which is a refracting surface closest to the image display element, and the number of reflections is three times from the eyeball of the observer to the image display element. Display device.

[5] The image display device according to any one of [1] to [4], wherein at least one of the surfaces forming the eyepiece optical system is a flat surface.

[6] The image display device according to the above [3] or [4], wherein the internal reflection on the first surface is total reflection.

[7] The above-mentioned [3], wherein the second surface is a reflecting surface having a concave surface facing the first surface.
The image display device according to any one of [6] to [6].

[8] The image according to any one of [3] to [7], wherein the first surface is a transmission surface and a reflection surface having a convex surface facing the second surface. Display device.

[0140]

[9] The image display device according to any one of [3] to [7], wherein the first surface is a flat transmission surface and a reflection surface.

[10] The above-mentioned [3], wherein the internal reflection region of the first surface is reflection-coated.
Alternatively, the image display device according to [4].

[11] The image display according to the above [3], [4] or [10], wherein the first surface is a transmission surface and a reflection surface with a concave surface facing the second surface. apparatus.

[12] The image display device according to the above [3], [4] or [10], wherein the second surface is a reflecting surface having a convex surface facing the first surface.

[13] When the incident angle of the axial chief ray at the first reflection in the backward ray tracing on the second surface is θ ₂ , 0 ° <θ ₂ <50 ° (1) The image display device according to the above [3] or [4].

[14] When the incident angle of the axial chief ray at the first reflection in the backward ray tracing on the second surface is θ ₂ , 10 ° <θ ₂ <40 ° (2) The image display device according to the above [3] or [4].

[15] When the incident angle of the axial chief ray on the first surface is θ ₁ , −20 ° <θ ₁ <40 ° (3), wherein [3] Alternatively, the image display device according to [4].

[16] When the incident angle of the axial chief ray on the first surface is θ ₁ , then -10 ° <θ ₁ <25 ° (4). [3] Alternatively, the image display device according to [4].

[17] When the incident angle of the axial chief ray in the internal reflection on the first surface is θ ₃ , then 20 ° <θ ₃ <70 ° (5) 3] or the image display device according to [4].

[18] When the incident angle of the axial chief ray in the internal reflection of the first surface is θ ₃ , then 30 ° <θ ₃ <55 ° (6) 3] or the image display device according to [4].

[19] The incident angle of the axial chief ray at the second reflection in the backward ray tracing on the second surface in the case of the three-sided structure or in the third surface in the case of the four-sided structure, When it is set to θ ₄ , 20 ° <θ ₄ <80 ° (7) The image display device according to the above [3] or [4].

[20] The incident angle of the axial chief ray at the second reflection in the backward ray tracing on the second surface in the case of the three-sided structure or on the third surface in the case of the four-sided structure, when the _{θ 4, 30 ° <θ 4} < [3] above that being a 65 ° ··· (8) or [4] the image display apparatus according.

[21] The third surface in the case of a three-sided structure,
Alternatively, when the incident angle of the axial chief ray on the fourth surface in the case of a four-sided structure is θ ₅ , it is −30 ° <θ ₅ <40 ° (9). 3] or the image display device according to [4].

[22] When the incident angle of the axial chief ray on the surface of the image display element is θ _i , −40 ° <θ _i <40 ° (10) ] Or [4] the image display device.

[23] When the incident angle of the axial chief ray on the image display element surface is θ _i , −25 ° <θ _i <25 ° (11) ] Or [4] the image display device.

[24] When the d-line refractive index of the medium having a refractive index larger than 1 is N _d , 1.45 <N _d <2.0 (12) The image display device according to the above [3] or [4].

[25] When the d-line refractive index of the medium having a refractive index larger than 1 is N _d , it is 1.5 <N _d <2.0 (13) The image display device according to the above [3] or [4].

[26] The image display device according to any one of [1] to [4], wherein at least one surface constituting the eyepiece optical system is an aspherical surface.

[27] The image display device according to the above [26], wherein at least one surface constituting the eyepiece optical system is an anamorphic surface.

[28] The image display device according to the above [26], wherein at least one surface constituting the eyepiece optical system is a free-form surface.

[29] The image display device according to the above [3] or [4], wherein the display surface of the image display element is arranged to be inclined with respect to the axial principal ray.

[30] The above-mentioned [3], [4] or [29], wherein the image display element is arranged with the back side of the display surface of the image display element facing the observer. The image display device described.

[31] The image described in any one of [1] to [30] above, which has a positioning means for positioning the image display element and the eyepiece optical system with respect to the observer's head. Display device.

[32] The image according to any one of the above [1] to [31], which has a supporting means for supporting the image display element and the eyepiece optical system with respect to the observer's head. Display device.

[33] The image display device according to any one of the above [1] to [32], which has a supporting means for supporting at least two sets of the image display device at a constant interval.

[33] The image forming optical system according to any one of [1] to [30], wherein the eyepiece optical system in the image display device is used as an image forming optical system.

[0166]

As is apparent from the above description, according to the image display device of the present invention, it is possible to provide a very small and lightweight image display device with a wide observation angle of view.

[Brief description of drawings]

FIG. 1 is a first embodiment of an eyepiece optical system of an image display device of the present invention.
FIG.

FIG. 2 is a second embodiment of the eyepiece optical system of the image display device of the present invention.
FIG.

FIG. 3 is a third embodiment of the eyepiece optical system of the image display device of the present invention.
FIG.

FIG. 4 is a fourth embodiment of the eyepiece optical system of the image display device of the present invention.
FIG.

FIG. 5 is a fifth embodiment of the eyepiece optical system of the image display device of the present invention.
FIG.

FIG. 6 is a sixth embodiment of the eyepiece optical system of the image display device of the present invention.
FIG.

FIG. 7 is a seventh embodiment of the eyepiece optical system of the image display device of the present invention.
FIG.

FIG. 8 is an eighth embodiment of the eyepiece optical system of the image display device of the present invention.
FIG.

FIG. 9 is a ninth embodiment of the eyepiece optical system of the image display device of the present invention.
FIG.

FIG. 10 is an optical path diagram of Example 10 of the eyepiece optical system of the image display device of the present invention.

FIG. 11 is a part of a lateral aberration diagram of Example 1 of the present invention.

FIG. 12 is a remaining part of the lateral aberration diagram of Example 1 of the present invention.

FIG. 13 is the remaining portion of the lateral aberration diagram for Example 1 of the present invention.

FIG. 14 is an explanatory diagram of internal reflection on the first surface of the eyepiece optical system according to the present invention.

FIG. 15 is an explanatory diagram showing the relationship between the shape of the first surface and the total reflection of the eyepiece optical system according to the present invention.

FIG. 16 is a diagram defining an incident angle at which an axial chief ray is incident on each surface.

FIG. 17 is a sectional view and a perspective view of a head-mounted image display device according to the present invention.

FIG. 18 is a configuration diagram when the optical system according to the present invention is used as an imaging optical system.

FIG. 19 is a configuration diagram of an optical system when the optical system according to the present invention is used as an imaging optical system.

FIG. 20 is a diagram showing an optical system of one conventional image display device.

FIG. 21 is a diagram showing an optical system of another conventional image display device.

FIG. 22 is a diagram showing an optical system of still another conventional image display device.

FIG. 23 is a diagram showing an optical system of another conventional image display device.

[Explanation of symbols]

 1 ... Observer pupil position 2 ... Observer visual axis 3 ... Eyepiece optical system 4 ... Image display element 5 ... First surface of eyepiece optical system 6 ... Second surface of eyepiece optical system 7 ... Third surface of eyepiece optical system 11 ... 1st surface of eyepiece optical system 12 ... 2nd surface of eyepiece optical system 13 ... 3rd surface of eyepiece optical system 14 ... 4th surface of eyepiece optical system 20 ... headband 21 ... liquid crystal shutter 22 ... see-through compensation optical system 31 Head-mounted image display device (HMD) Ob ... Shooting optical system Fi ... Viewfinder optical system Ca ... Compact camera GF ... Front lens group D ... Brightness diaphragm DS ... Eyepiece optical system (present invention) Lt ... Objective optical system P … Holo prism Oc… Eyepiece

Claims (4)

[Claims] 1. An image display device comprising an image display element for displaying an image and an eyepiece optical system for projecting the image formed by the image display element and guiding the image to an observer's eyeball, wherein the eyepiece optical system comprises: The number of reflections of the light emitted from the image display element until reaching the observer's eye is an odd number of 3 or more, and the surface of the eyepiece optical system immediately before the observer's eye is internally reflected, An image display device, characterized in that the image display device is a refracting surface that exits the eyepiece optical system. 2. An image display device comprising an image display element for displaying an image and an eyepiece optical system for projecting the image formed by the image display element and guiding the image to an observer's eyeball. The number of reflections of the light beam emitted from the image display element before reaching the observer's eyeball is three, and the surface of the eyepiece optical system immediately before the observer's eyeball has internal reflection and the eyepiece optical system. An image display device, which is a refracting surface for emitting light. 3. An image display device comprising an image display element for displaying an image and an eyepiece optical system for projecting the image formed by the image display element and guiding it to an observer's eyeball, wherein the eyepiece optical system is at least 3 It has one surface and the space formed by the at least three surfaces has a refractive index of 1
Filled with a larger medium, the first surface is a refraction surface and an internal reflection surface, facing the first surface, in the order in which light rays pass according to the reverse ray tracing from the observer's eyeball to the image display element, The second surface is a reflecting surface that is eccentric or inclined with respect to the observer's visual axis, and the third surface is a refracting surface that is closest to the image display element. An image display device, characterized in that the number of reflections is three before reaching an element. 4. An image display device comprising an image display element for displaying an image and an eyepiece optical system for projecting an image formed by the image display element and guiding the image to an observer's eyeball, wherein the eyepiece optical system is at least 4 The space formed by the at least four surfaces has a refractive index of 1
Filled with a larger medium, the first surface is a refraction surface and an internal reflection surface, in opposition to the first surface, in the order in which the light rays pass according to the reverse ray tracing from the observer's eye to the image display element, A second surface, which is a reflecting surface that is eccentric or inclined with respect to the observer's visual axis, and a third surface that faces the first surface and is adjacent to the second surface.
And a fourth surface which is a refracting surface closest to the image display element, and the number of reflections is three times from the eyeball of the observer to the image display element. Display device.