JP6728312B2 - Electroluminescent display - Google Patents

Description

The present invention relates to an electroluminescent display device, and more particularly, to an electroluminescent display device capable of improving light extraction efficiency and viewing angle.

2. Description of the Related Art Recently, flat panel displays having excellent characteristics such as thinness, light weight, and low power consumption have been developed and used in various fields.

BACKGROUND OF THE INVENTION Among flat panel display devices, an electroluminescent display device is a device that emits electrons and positive electrons when a charge is injected into a light emitting layer formed between a cathode, which is an electron injecting electrode, and an anode, which is a hole injecting electrode. The holes form excitons, and the excitons recombine radiatively to emit light.

Since such an electroluminescent display device can be formed on a flexible substrate such as plastic and is self-luminous, it has a large contrast ratio and a response time of about several microseconds (μs). , Becomes an advantage when displaying moving images. Further, it has a wide viewing angle, can be stably driven even at a low temperature, and can be driven with a low voltage of DC 5V to 15V, so that there is an advantage that a drive circuit can be easily designed and manufactured.

FIG. 1 is a sectional view schematically showing a conventional light emitting display device.

As shown in FIG. 1, the light emitting display device 1 includes a substrate 10, a thin film transistor Tr located on the substrate 10, and a light emitting diode D located on the substrate 10 and connected to the thin film transistor Tr. An encapsulation layer (not shown) may be formed on the light emitting diode D.

Here, the light emitting diode D includes a first electrode 41, a light emitting layer 42, and a second electrode 43, and light from the light emitting layer 42 is emitted to the outside via the second electrode 43.

In this way, the light emitted from the light emitting layer 42 passes through various components of the electroluminescent display device 1 and is emitted in the upper direction of the electroluminescent display device 1.

However, the surface plasmon component generated at the boundary between the metal and the light emitting layer 42 and the optical waveguide mode constituted by the light emitting layers 42 inserted inside the reflecting layers on both sides occupy about 60 to 70% of the emitted light. ..

As a result, among the light emitted from the light emitting layer 42, there is light trapped inside the electroluminescent display device 1 instead of being emitted to the outside of the electroluminescent display device 1, and the light extraction efficiency of the electroluminescent display device 1 is increased. There was a problem that it decreased.

JP2007-173200A

The present invention provides an electroluminescent display device in which a plurality of metal patterns spaced apart from each other are arranged under a light emitting diode and a reflective electrode covering the plurality of metal patterns is formed to improve light extraction efficiency and a viewing angle. The purpose is to provide.

In order to achieve the above-described object, the present invention provides a thin film transistor disposed on a substrate, a protective layer disposed on the thin film transistor, and a protective layer disposed on the protective layer. A plurality of metal patterns, a plurality of metal patterns and a reflective electrode that is disposed along the shape of the upper surface of the protective layer, and includes a plurality of protruding portions; and a reflective electrode that is disposed on the protective layer and the reflective electrode. An overcoat layer including an opening exposing an upper surface of each of the protruding portions, a first electrode disposed on the reflective electrode and the overcoat layer, and electrically connected to the reflective electrode, and a first electrode. Provided is a light emitting display device including a light emitting layer disposed on the top of the light emitting layer and a second electrode disposed on the top of the light emitting layer.

In the present invention, a plurality of metal patterns are arranged in a shape spaced apart from each other under the light emitting diode, and a reflective electrode is formed to cover the plurality of metal patterns to improve light extraction efficiency and improve a viewing angle. be able to.

FIG. 3 is a cross-sectional view schematically showing a general light emitting display device. FIG. 6 is a circuit diagram showing one sub-pixel region in an electroluminescent display device according to an exemplary embodiment of the present invention. 1 is a cross-sectional view schematically showing an electroluminescent display device according to an exemplary embodiment of the present invention. It is an enlarged view of the area|region of A in FIG. FIG. 3 is a diagram schematically showing a light path in an electroluminescent display device according to an exemplary embodiment of the present invention. FIG. 3 is a plan view schematically showing a metal pattern of an electroluminescent display device according to an exemplary embodiment of the present invention. FIG. 3 is a plan view schematically showing a metal pattern of an electroluminescent display device according to an exemplary embodiment of the present invention. FIG. 3 is a plan view schematically showing a metal pattern of an electroluminescent display device according to an exemplary embodiment of the present invention. FIG. 6 is a diagram schematically showing a light path according to a distance between a plurality of metal patterns in the light emitting display device according to an embodiment of the present invention. FIG. 6 is a diagram schematically showing a light path according to a distance between a plurality of metal patterns in the light emitting display device according to an embodiment of the present invention. FIG. 6 is a diagram schematically showing a light path according to a distance between a plurality of metal patterns in the light emitting display device according to an embodiment of the present invention. FIG. 6 is a diagram schematically showing a light path according to a distance between a plurality of metal patterns in the light emitting display device according to an embodiment of the present invention. FIG. 6 is a diagram schematically showing a light path according to an angle formed by a second surface of a metal pattern and first and second slopes in an electroluminescent display device according to an exemplary embodiment of the present invention. FIG. 6 is a diagram schematically showing a light path according to an angle formed by a second surface of a metal pattern and first and second slopes in an electroluminescent display device according to an exemplary embodiment of the present invention. FIG. 5 is a diagram schematically showing a light path according to an angle formed by a second surface of a metal pattern and a first slope and a second slope in an electroluminescent display device according to an exemplary embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a circuit diagram showing one sub-pixel region in the light emitting display device according to the embodiment of the present invention.

As shown in FIG. 2, the light emitting display device according to the embodiment of the present invention includes a gate line GL and a data line DL that intersect with each other to define a sub-pixel region SP, and each sub-pixel region SP includes: A switching thin film transistor Ts, a driving thin film transistor Td, a storage capacitor Cst, and a light emitting diode D are formed.

More specifically, the gate electrode of the switching thin film transistor Ts is connected to the gate line GL, and the source electrode is connected to the data line DL. The gate electrode of the driving thin film transistor Td is connected to the drain electrode of the switching thin film transistor Ts, and the source electrode is connected to the high potential voltage VDD. The anode of the light emitting diode D is connected to the drain electrode of the driving thin film transistor Td, and the cathode is connected to the low potential voltage VSS. The storage capacitor Cst is connected to the gate electrode and the drain electrode of the driving thin film transistor Td.

The operation of displaying an image by the electroluminescent display device will be described. When the switching thin film transistor Ts is turned on by the gate signal applied through the gate line GL, the data signal from the data line DL is driven through the switching thin film transistor Ts. The voltage is applied to the gate electrode of the thin film transistor Td and one electrode of the storage capacitor Cst.

The driving thin film transistor Td is turned on by a data signal and controls a current flowing through the light emitting diode D to display an image. The light emitting diode D emits light by the current of the high potential voltage VDD supplied via the driving thin film transistor Td.

That is, the amount of current flowing through the light emitting diode D is proportional to the magnitude of the data signal, and the intensity of light emitted by the light emitting diode D is proportional to the amount of current flowing through the light emitting diode D. , Different gradations are displayed depending on the size of the data signal, and as a result, the electroluminescent display device displays an image.

The storage capacitor Cst maintains a charge corresponding to a frame data signal when the switching thin film transistor (Ts) is turned off. Therefore, even if the switching thin film transistor Ts is turned off, the storage capacitor Cst keeps the amount of current flowing through the light emitting diode D constant and keeps the gradation displayed by the light emitting diode D constant until the next frame.

On the other hand, in the sub-pixel region SP, another transistor and/or capacitor may be further formed in addition to the switching thin film transistor Ts, the driving thin film transistor Td, and the storage capacitor Cst.

FIG. 3 is a schematic cross-sectional view of an electroluminescent display device according to an exemplary embodiment of the present invention.

As shown in FIG. 3, the light emitting display device 100 according to the embodiment of the present invention includes a first substrate 110, a thin film transistor 120, a plurality of metal patterns MP, a reflective electrode RE, an overcoat layer 160, and a light emitting diode D. You can

The light emitting display device 100 according to the embodiment of the present invention shows a top emission type in which light from the light emitting layer 142 is emitted to the outside through the second electrode 143, but is not limited thereto.

The light emitting display device 100 according to the embodiment of the present invention may include the thin film transistor 120 including the gate electrode 121, the active layer 122, the source electrode 123, and the drain electrode 124 on the first substrate 110.

Specifically, the gate electrode 121 and the gate insulating film 131 of the thin film transistor 120 may be disposed on the first substrate 110.

Then, the active layer 122 that overlaps the gate electrode 121 can be disposed on the gate insulating film 131.

In addition, an etch stopper 132 may be disposed on the active layer 122 to protect the channel region of the active layer 122.

Then, the source electrode 123 and the drain electrode 124 that are in contact with the active layer 122 may be disposed on the active layer 122.

The light emitting display device to which the embodiment of the present invention can be applied is not limited to that shown in FIG. A buffer layer may be further provided between the first substrate 110 and the active layer 122, and the etch stopper 132 may not be provided.

On the other hand, for convenience of description, only a driving thin film transistor is shown among various thin film transistors that may be included in the light emitting display device 100. In the thin film transistor 120, the gate electrode 121 is a source electrode 123 and a drain is based on the active layer 122. Although it has been described that the structure is the inverted stagger structure or the bottom gate structure located on the opposite side of the electrode 124, this is an example. The gate electrode 121 may be a thin film transistor having a coplanar structure or a top gate structure in which the gate electrode 121 is located on the same side as the source electrode 123 and the drain electrode 124 based on the active layer 122.

In addition, a protective layer 133 can be provided on the drain electrode 124 and the source electrode 123.

Here, although it is shown that the upper portion of the thin film transistor 120 is flattened by the protective layer 133, the protective layer 133 does not flatten the upper portion of the thin film transistor 120 and follows the surface shape of the component located in the lower portion. It may be arranged.

In addition, a plurality of metal patterns MP, which are spaced apart from each other, may be disposed on the protective layer 133 in the light emitting area EA of the light emitting display device 100 according to the embodiment of the present invention.

That is, in the light emitting area EA, a plurality of metal patterns MP that are separated from each other may be disposed, and the protective layer 133 may be exposed between the plurality of metal patterns MP.

Here, the light emitting area EA means an area where the light emitting layer 142 emits light by the first electrode 141 and the second electrode 143.

Further, each of the plurality of metal patterns MP can be formed as a single layer or a multilayer made of copper (Cu), molybdenum (Mo), titanium (Ti), or an alloy thereof, but is not limited thereto. is not.

Further, the cross sections of the plurality of metal patterns MP may have a trapezoidal shape, but are not limited to this.

Here, in the light emitting display device 100 according to the embodiment of the present invention, the reflective electrode RE may be arranged along the top shapes of the plurality of metal patterns MP and the protective layer 133.

In other words, the reflective electrode RE can form the plurality of protrusions PP along the shapes of the plurality of metal patterns MP.

Here, the upper surface of each of the plurality of protrusions PP may be formed flat.

The reflective electrode RE may be made of APC alloy, but is not limited thereto.

Here, the APC alloy means an alloy of silver (Ag), palladium (Pd) and copper (Cu).

In addition, the reflective electrode RE can be connected to the source electrode 123 of the thin film transistor 120 via a contact hole formed in the protective layer 133. However, the present invention is not limited to this, and the first electrode 141 on the reflective electrode RE may be connected to the source electrode 123 of the thin film transistor 120.

Although the light emitting display device 100 according to the exemplary embodiment of the present invention has been described with the N-type thin film transistor as an example, the reflective electrode RE is connected to the source electrode 123, but the present invention is not limited thereto. When 120 is a P-type thin film transistor, the reflective electrode RE may be connected to the drain electrode 124.

The reflective electrode RE can be formed separately for each pixel region.

The shapes of the plurality of metal patterns MP and the reflective electrode RE will be described in more detail later.

An overcoat layer 160 may be disposed on the protective layer 133 and the reflective electrode RE.

Here, the overcoat layer 160 in the light emitting display device 100 according to the embodiment of the present invention may include a plurality of openings 160a.

Here, each of the plurality of openings 160a can be formed corresponding to each of the plurality of protrusions PP in the reflective electrode RE.

That is, the overcoat layer 160 may be formed on the reflective electrode RE corresponding to a region in which the plurality of metal patterns MP are spaced apart from each other, and the upper surface of each of the plurality of protrusions PP of the reflective electrode RE may be formed on the upper surface of the overcoat layer 160. The first electrode 141 can be in contact with the first electrode 141.

As a result, the upper surface of the reflective electrode RE exposed through the opening 160a and the upper surface of the overcoat layer 160 can be formed flat without any step. That is, the exposed upper surface of the reflective electrode RE may be flush with the upper surface of the overcoat layer 160.

Here, the overcoat layer 160 including the opening 160a exposing the upper surface of each of the plurality of protrusions PP in the reflective electrode RE can be formed by a process such as photolithography, wet etching, or dry etching.

The overcoat layer 160 may be made of an organic material having a refractive index of about 1.5 to 1.55, but is not limited thereto.

On the other hand, the first electrode 141 may be disposed on the overcoat layer 160 and the reflective electrode RE exposed through the opening 160a.

Further, the overcoat layer 160 and the first electrode 141 disposed above the reflective electrode RE exposed through the opening 160a can be formed flat and are formed separately for each sub-pixel region. However, the present invention is not limited to this.

Here, the first electrode 141 may be an anode or a cathode for supplying one of electrons or holes to the light emitting layer 142.

The case where the first electrode 141 of the light emitting display according to the embodiment of the present invention is an anode will be described as an example.

Here, the first electrode 141 includes ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), ZTO (Zinc Tin Oxide), SnO ₂ (Tin Oxide), ZnO (Zinc Oxide), In ₂ O ₃ (Indium Oxide). ), GITO (Galium Indium Tin Oxide), IGZO (Indium Gallium Zinc Oxide), ZITO (Zinc Indium Tin Oxide), IGO (Indium Gallium Oxide), Ga ₂ OZ (Oudium Oxide), Ga ₂ O ₃ (AuO) (Galium Oxide). It may include any one selected from the group consisting of GZO (Gallium Zinc Oxide).

Then, the first electrode 141 can contact the upper surfaces of the plurality of protrusions PP of the reflective electrode RE.

Thereby, the microcavity effect can be obtained in the region where the first electrode 141 and the plurality of protrusions PP of the reflective electrode RE are in contact with each other.

Further, the first electrode 141 may be in contact with and electrically connected to the light emitting layer 142 via a conductive material.

Here, the first electrode 141 may have a refractive index of approximately 1.8 or more, but is not limited thereto.

Then, the bank layer 136 can be disposed on the overcoat layer 160 and the first electrode 141.

In addition, the bank layer 136 may include an opening 136a exposing the first electrode 141.

Here, the bank layer 136 may be disposed between the adjacent pixel (or sub-pixel) regions and may serve to partition the adjacent pixel (or sub-pixel) regions.

Further, the bank layer 136 may be formed of a photoacrylic organic material having a refractive index of 1.6 or less, but is not limited thereto.

The light emitting layer 142 may be disposed on the first electrode 141 and the bank layer 136.

The light emitting layer 142 emits white light, and thus may have a tandem white structure in which a plurality of light emitting layers are stacked.

For example, the light emitting layer 142 may include a first light emitting layer that emits blue light and a second light emitting layer that is disposed on the first light emitting layer and that emits light of a color that becomes white when mixed with blue light. ..

Here, the second light emitting layer may be a light emitting layer that emits yellow-green light.

Meanwhile, the light emitting layer 142 may include only a light emitting layer that emits one of blue light, red light, and green light.

In addition, the light emitting layer 142 may be disposed in the light emitting area EA so as to follow the shape of the first electrode 141.

That is, the light emitting layer 142 can be formed flat in the light emitting region EA.

Here, the light emitting layer 142 may be formed of an organic material having a refractive index of approximately 1.8 or more, but is not limited thereto and may be an inorganic light emitting material such as a quantum dot. ..

Meanwhile, a second electrode 143 for supplying one of electrons or holes to the light emitting layer 142 may be disposed on the light emitting layer 142.

Here, the second electrode 143 may be an anode or a cathode.

The case where the second electrode 143 of the light emitting display device 100 according to the embodiment of the present invention is a cathode will be described as an example.

The second electrode 143 may be made of a transparent metal material (TCO, Transparent Conductive Material), such as ITO or IZO, which can transmit light, and may be made of magnesium (Mg), silver (Ag), or magnesium (Mg). ) And a silver (Ag) alloy, such as a semi-transmissive conductive material.

Here, the second electrode 143 may be arranged along the shape of the light emitting layer 142.

That is, in the light emitting area EA, the second electrode 143 can be formed flat.

Thus, the first electrode 141, the light emitting layer 142, and the second electrode 143 form the light emitting diode D.

Then, a sealing layer (not shown) can be formed on the second electrode 143, and the sealing layer (not shown) of the first substrate 110 and the second substrate (not shown) are bonded to form a book. The light emitting display device 100 according to the embodiment of the present invention may be embodied.

Here, a color filter (not shown) and a black matrix (not shown) may be formed on the second substrate.

FIG. 4 is an enlarged view of the area A in FIG.

As shown in FIG. 4, the electroluminescent display device 100 according to the exemplary embodiment of the present invention includes a plurality of metal patterns MP, a reflective electrode RE, an overcoat layer 160, a first electrode 141, and a light emitting layer 142 on the protective layer 133. And the second electrode 143 can be arranged.

In other words, a plurality of metal patterns MP that are separated from each other may be disposed on the protective layer 133 in the light emitting area EA.

Here, each of the plurality of metal patterns MP connects the first surface M1 that contacts the upper surface P1 of the protrusion PP, the second surface M2 that contacts the protective layer 133, and the first surface M1 and the second surface M2. The first slope M3 and the second slope M4 may be included.

Here, the first surface M1 and the second surface M2 can be formed flat, and the area of the second surface M2 can be made larger than the area of the first surface M1.

The angle (θ) formed by the second surface M2 and the first slope M3 and the second slope M4 may be an acute angle.

Here, the acute angle may be 20° to 70°, but is not limited thereto.

That is, each of the plurality of metal patterns MP may have a trapezoidal cross section, but is not limited thereto.

Then, the plurality of metal patterns MP can be arranged with a separation distance G.

Therefore, the protective layer 133 may be exposed in a region where the plurality of metal patterns MP are separated. That is, the protective layer 133 may be exposed in a region between the adjacent metal patterns MP.

Here, the separation distance G between the plurality of metal patterns MP may be 0.5 μm to 2 μm, but is not limited thereto.

The length d of the first surface M1 of each of the plurality of metal patterns MP may be 1 μm to 5 μm, but is not limited thereto.

The height H of each of the plurality of metal patterns MP may be 0.5 μm to 1 μm, but is not limited thereto.

Here, the height H of the metal pattern MP means the distance between the first surface M1 and the second surface M2.

Further, each of the plurality of metal patterns MP can be formed as a single layer or a multilayer made of copper (Cu), molybdenum (Mo), titanium (Ti), or an alloy thereof, but is not limited thereto. is not.

Here, in the light emitting display device 100 according to the embodiment of the present invention, the reflective electrode RE may be arranged along the top shapes of the plurality of metal patterns MP and the protective layer 133.

That is, the reflective electrode RE may include a plurality of protruding portions PP and a connecting portion CP that connects the plurality of protruding portions PP along the top surfaces of the plurality of metal patterns MP and the protective layer 133.

Each of the plurality of protrusions PP may include an upper surface P1 that contacts the first electrode 141 and side surfaces P2 and P3 that connect the upper surface P1 and the connecting portion CP. In the embodiment of the present invention, the upper surface P1 and the side surfaces P2, P3 of each of the plurality of protruding portions PP may be referred to as the upper surface portion P1 and the side surface portions P2, P3, respectively, and may be interchanged with each other.

Here, the side surfaces P2 and P3 may have a predetermined inclination.

The connection part CP may be disposed between the plurality of protrusions PP and may contact the protective layer 133.

Here, the upper surface P1 and the connecting portion CP of each of the plurality of protruding portions PP can be formed flat. In other words, in the reflective electrode RE, the flat upper surface P1 and the flat connecting portion CP having different heights can be alternately arranged.

As described above, the light emitting display device according to the embodiment of the present invention (100 in FIG. 3) includes the plurality of metal patterns MP spaced apart from each other on the protection layer 133, and the protection layer 133 and the plurality of metal patterns MP. By forming the reflective electrode RE covering the flat surface P1, the flat upper surfaces P1 and the flat connecting portions CP of the projecting portions PP having different heights are alternately arranged, and the flat upper surface P1 of the projecting portions PP and the flat connecting portion CP are arranged. It is possible to form the reflective electrode RE having the inclined side surfaces P2 and P3 that connect with each other.

Then, the overcoat layer 160 may be disposed on the protective layer 133 and the reflective electrode RE.

Here, the overcoat layer 160 of the light emitting display device (100 in FIG. 3) according to the embodiment of the present invention may include an opening 160a exposing the upper surface P1 of each of the plurality of protrusions PP of the reflective electrode RE. it can.

That is, the overcoat layer 160 fills the spaces between the plurality of protrusions PP of the reflective electrode RE, so that the reflective electrode RE and the first electrode 141 are electrically connected to each other through the opening 160 a of the overcoat layer 160. The overcoat layer 160 planarizes the upper portion of the reflective electrode RE.

Also, the overcoat layer 160 may be made of an organic material having a refractive index of about 1.5 to 1.55, but is not limited thereto.

Then, the first electrode 141 may be disposed on the reflective electrode RE and the overcoat layer 160.

The first electrode 141 may include, but is not limited to, an amorphous metal oxide having a refractive index of about 1.8 or more.

The first electrode 141 may be flatly disposed on the reflective electrode RE and the overcoat layer 160.

Therefore, the first electrode 141 can contact the upper surfaces P1 of the plurality of protrusions PP of the reflective electrode RE, and can not contact the side surfaces P2 and P3 of the reflective electrode RE and the connecting portion CP.

As a result, a microcavity may occur in a region where the first electrode 141 and the upper surfaces P1 of the plurality of protrusions PP of the reflective electrode RE are in contact with each other.

The microcavity is a light emitting diode D including a reflective electrode RE, a first electrode 141 (anode electrode), a light emitting layer 142, and a second electrode 143 (cathode electrode), and the thickness of each electrode and the light emitting layer 142 is appropriately adjusted. , Changing the emission spectrum by multiple reflections of light.

Further, the light emitting layer 142 may be disposed on the first electrode 141, and the light emitting layer 142 in the light emitting region (EA in FIG. 3) may be formed flat.

Here, the light emitting layer 142 may be formed of an organic material having a refractive index of approximately 1.8 or more, but is not limited thereto and may be an inorganic light emitting material such as a quantum dot. ..

On the other hand, the second electrode 143 can be disposed on the light emitting layer 142, and the second electrode 143 in the light emitting region (EA in FIG. 3) can be formed flat.

Thus, the first electrode 141, the light emitting layer 142, and the second electrode 143 form the light emitting diode D.

Here, the light emitting diode D can be formed flat in the light emitting area EA.

With such a structure, in the electroluminescent display device (100 of FIG. 3) according to the embodiment of the present invention, the microcavity region where the first electrode 141 and the upper surfaces P1 of the plurality of protrusions PP of the reflective electrode RE are in contact with each other. In (Micro Cavity Area: MCA), the light extraction efficiency and color reproducibility can be enhanced by utilizing the microcavity effect.

Then, the non-micro cavity area (Non-Micro Cavity Area) corresponding to the side surfaces P2 and P3 of the plurality of protrusions PP and the connecting portion CP in the reflective electrode RE that does not contact the first electrode 141 is a non-micro cavity area (Non-Micro Cavity Area: In the NMCA), the light extraction efficiency can be further improved by reflecting the light that is totally reflected inside the light emitting diode D and cannot be emitted to the outside to be extracted to the outside. Particularly, in the non-microcavity area (NMCA), the straightness of the light emitted along the shape of the reflective electrode RE is reduced and the light is emitted in the lateral direction, so that the conventional microcavity-effect applied electroluminescence display is used. In the device, it is possible to effectively improve the brightness reduction and the color shift in which the color shifts from the long wavelength to the short wavelength, which occurs as the viewing angle increases.

FIG. 5 is a diagram schematically illustrating a light path in an electroluminescent display device according to an exemplary embodiment of the present invention. Description will be made with reference to FIG.

As shown in FIG. 5, in the electroluminescent display device (100 of FIG. 3) according to the embodiment of the present invention, the microcavity region (the upper surface P1 of the plurality of protrusions PP of the reflective electrode RE is in contact with the first electrode 141 ( A non-microcavity area (NMCA) corresponding to the side surfaces P2 and P3 of the reflective electrode RE and the connecting portion CP that are not in contact with the first electrode 141 may be included between the MCAs.

The light L1 emitted to the outside by utilizing the microcavity effect in the microcavity region (MCA) and the light L1 reflected by the side surfaces P2 and P3 of the reflective electrode RE and the connecting portion CP in the non-microcavity region (NMCA) and emitted to the upper part. The light L2 is mixed to improve the light extraction efficiency and the viewing angle.

That is, in the non-microcavity area (NMCA), the straightness of the light emitted along the shape of the reflective electrode RE is reduced and the light is emitted in the lateral direction, so that the conventional electroluminescence display to which the microcavity effect is applied is applied. In the device, it is possible to effectively improve the brightness reduction and the color shift in which the color shifts from the long wavelength to the short wavelength, which occurs as the viewing angle increases.

6A through 6C are plan views schematically showing metal patterns of an electroluminescent display device according to an exemplary embodiment of the present invention.

As shown in FIGS. 6A to 6C, the light emitting display device (100 of FIG. 3) according to the embodiment of the present invention may include a plurality of metal patterns MP on the protective layer 133.

That is, as shown in FIG. 6A, each of the plurality of metal patterns MP may have a quadrangular shape in a plan view, and each of the plurality of metal patterns MP may be arranged apart from each other. The protective layer 133 may be exposed in the space separated by the pattern MP.

Further, as shown in FIG. 6B, each of the plurality of metal patterns MP has a hexagonal shape in plan view, and each of the plurality of metal patterns MP can be arranged apart from each other. The protective layer 133 may be exposed in a space separated from each other.

Then, as shown in FIG. 6C, each of the plurality of metal patterns MP has a circular shape in plan view, and each of the plurality of metal patterns MP can be arranged apart from each other. The protective layer 133 may be exposed in a space separated from each other.

Here, the planar shapes of the plurality of metal patterns MP shown in FIGS. 6A to 6C are examples, and the present invention is not limited thereto. Each of the plurality of metal patterns MP may have various planar shapes.

7A to 7D are views schematically showing light paths according to a distance between a plurality of metal patterns in an electroluminescent display device according to an exemplary embodiment of the present invention. Description will be made with reference to FIG.

Here, the angle (θ) formed between the second surface M2 of each of the plurality of metal patterns MP and the first slope M3 and the second slope M4 in the electroluminescent display device (100 of FIG. 3) of FIGS. 7A to 7D. Are the same at 30°, and show the paths of light due to changes in the separation distance G of the plurality of metal patterns MP.

FIG. 7A shows a light path when the separation distance G of the plurality of metal patterns MP is 0.5 μm, and FIG. 7B shows light paths when the separation distance G of the plurality of metal patterns MP is 1 μm. Shows the route. 7C shows a light path when the separation distance G of the plurality of metal patterns MP is 1.5 μm, and FIG. 7D shows a case where the separation distance G of the plurality of metal patterns MP is 2 μm. The path of light is shown.

Comparing FIGS. 7A to 7D, it can be seen that the light extraction efficiency is highest when the distance G between the plurality of metal patterns MP shown in FIG. 7C is 1.5 μm.

That is, in the non-microcavity area (NMCA) corresponding to the side surfaces P2 and P3 of the plurality of protrusions PP and the connection portion CP in the reflective electrode RE that does not contact the first electrode 141, the light is internally reflected from the inside of the light emitting diode D. The light that could not be emitted to the upper part can be reflected to the upper part along the shape of the connecting part CP of the reflective electrode RE and can be extracted most to the outside.

In addition, the ratio of the microcavity region to the non-microcavity region is set to 1:1 to 5:1, preferably 1:1 to improve the light extraction efficiency and to reduce the brightness and color shift phenomenon depending on the viewing angle. Can be effectively improved.

Therefore, in the light emitting display device (100 in FIG. 3) according to the embodiment of the present invention, the separation distance G between the plurality of metal patterns MP is set to 1.5 μm, and the light extraction efficiency can be further improved.

8A to 8C are schematic views illustrating a light path according to an angle formed between a second surface of a metal pattern and first and second slopes of an electroluminescent display device according to an exemplary embodiment of the present invention. Description will be made with reference to FIG.

FIG. 8A shows a light path when the angle (θ) formed by the second surface M2 of the metal pattern MP and the first and second slopes M3 and M4 is 30°, and FIG. 8B shows the metal pattern. 8C shows the path of light when the angle (θ) formed by the second surface M2 of MP and the first and second slopes M3 and M4 is 450°, and FIG. 8C shows the second pattern of the metal pattern MP. The light path when the angle (θ) formed by the surface M2 and the first and second slopes M3 and M4 is 60° is shown.

Comparing FIGS. 8A to 8C, the angles (θ) formed by the second surface M2 of the metal pattern MP and the first and second inclined surfaces M3 and M4 shown in FIGS. 8A and 8B are 30° and 45°. It can be seen that the light extraction efficiency in each case is high. It can be seen that when the angle (θ) formed by the second surface M2 of the metal pattern MP and the first and second slopes M3 and M4 is 60°, the light extraction efficiency is slightly reduced.

That is, when the angle (θ) formed between the second surface M2 of the metal pattern MP and the first and second inclined surfaces M3 and M4 is 30° and 45°, a plurality of reflective electrodes RE that do not contact the first electrode 141 are formed. In the non-microcavity area (NMCA) corresponding to the side surfaces P2, P3 of the protruding portion PP and the connecting portion CP, the light that is totally reflected inside the light emitting diode D and cannot be emitted to the outside is reflected to the upper side, and is reflected to the outside most. Many can be extracted.

Therefore, in the electroluminescent display device (100 of FIG. 3) according to the embodiment of the present invention, the angle (θ) formed by the second surface M2 of the plurality of metal patterns MP and the first and second slopes M3 and M4 is When it is formed at 30° to 45°, the light extraction efficiency can be further improved.

As described above, in the electroluminescent display device (100 of FIG. 3) according to the embodiment of the present invention, the microcavity area (MCA) where the first electrode 141 and the upper surfaces P1 of the plurality of protrusions PP of the reflective electrode RE are in contact with each other. In, the microcavity effect can be utilized to increase the light extraction efficiency and the color reproduction rate.

Further, in the non-microcavity region (NMCA) corresponding to the side surfaces P2, P3 of the plurality of protrusions PP and the connecting portion CP in the reflective electrode RE not in contact with the first electrode 141, the light is totally reflected inside the light emitting diode D and the outside. The light that could not be emitted to the upper part can be reflected to the upper part and extracted to the outside, further improving the light extraction efficiency, and the light (L1 in FIG. 5) emitted in the microcavity area (MCA) and the non-microcavity. The viewing angle can be improved by mixing the light (L2 in FIG. 5) emitted in the region (NMCA).

That is, in the non-microcavity region (NMCA), the straightness of the light emitted along the shape of the reflective electrode RE is reduced, and the light is emitted in the lateral direction, so that the conventional electroluminescence using the microcavity effect is applied. In the display device, it is possible to effectively improve the phenomenon that the brightness decreases as the viewing angle increases and the phenomenon that the color shifts from the long wavelength to the short wavelength.

In particular, the separation distance G of the plurality of metal patterns MP is formed to be 1.5 μm, and the angle (θ) formed by the second surface M2 of the plurality of metal patterns MP and the first and second slopes M3 and M4 is 30°. The brightness can be reduced and the color shift phenomenon can be improved more effectively by increasing the viewing angle.

Although the above description has been made with reference to the preferred embodiments, a person skilled in the art can, within the scope not departing from the technical idea and the scope of the present invention described in the claims, It will be appreciated that various modifications and variations of the present invention can be made.

1. A thin film transistor arranged on the upper part of the substrate,
A protective layer disposed on top of the thin film transistor,
A plurality of metal patterns spaced apart from each other on the protective layer,
A reflecting electrode that is arranged along the shape of the upper surfaces of the plurality of metal patterns and the protective layer and that includes a plurality of protrusions;
An overcoat layer that is disposed on the protective layer and the reflective electrode and that includes an opening that exposes the upper surface of each of the plurality of protrusions;
A first electrode disposed on the reflective electrode and the overcoat layer and electrically connected to the reflective electrode;
A light emitting layer disposed on the first electrode,
An electroluminescent display device comprising: a second electrode disposed on the light emitting layer.

2. Each of the plurality of metal patterns includes a first surface that contacts the upper surface of each of the plurality of protrusions, a second surface that contacts the protective layer and has a larger area than the first surface, and a first surface and a second surface. 2. The electroluminescent display device according to 1 above, which includes a first slope and a second slope to be connected.

3. 2. The electroluminescent display device according to 1, wherein the plurality of metal patterns have a separation distance of 0.5 μm to 2 μm.

4. The electroluminescent display device of claim 1, wherein the height of the plurality of metal patterns is 0.5 μm to 1 μm.

5. 3. The electroluminescent display device according to 2, wherein the first surface has a length of 1 μm to 5 μm.

6. 3. The electroluminescent display device according to 2, wherein an angle formed by the second surface and the first slope and the second slope is 20° to 70°.

7. 3. The electroluminescent display device according to 2 above, wherein the first electrode, the light emitting layer and the second electrode are arranged flat in a light emitting region.

8. 2. The electroluminescent display device according to 1, wherein the reflective electrode is electrically connected to the thin film transistor.

9. The electroluminescent display device according to 1, wherein the first electrode is electrically connected to the thin film transistor.

10. A substrate including one or more pixels,
Each pixel includes a second electrode and a reflective electrode, and a light emitting layer disposed between the second electrode and the reflective electrode, or between the second electrode and the reflective electrode, or between the second electrode and the reflective electrode. A light emitting structure including a light emitting layer disposed and a first electrode disposed between the light emitting layer and the reflective electrode,
Each of the pixels includes a plurality of microcavity regions spaced apart from each other and one or more non-microcavity regions disposed between the microcavity regions,
In the microcavity region, the combined thickness from the reflective electrode to the second electrode along the vertical direction of the light emitting structure is different from the combined thickness in the non-microcavity region,
The light emitting structure is configured to create a microcavity effect,
Each of the second electrode and the reflective electrode is formed to be flat in the microcavity region, and at least one of the second electrode and the reflective electrode is formed to have a non-flat surface in the non-microcavity region. Ruka,
Alternatively, each of the first electrode, the second electrode, and the reflective electrode is formed to be flat in the microcavity region, and at least one of the first electrode, the second electrode, and the reflective electrode is non-micro. A light emitting display device formed to have a non-flat surface in a cavity region.

11. The electroluminescent device according to claim 10, wherein a combined thickness of the reflective electrode and the second electrode along the vertical direction of the light emitting structure has a value smaller than a combined thickness of the non-microcavity region in the microcavity region. Display device.

12. Each of the plurality of microcavity regions is formed to have a circular shape, a rectangular shape, a square shape, a rhombic shape, a hexagonal shape, or another polygonal shape which is arranged so as to be spaced apart from each other in one pixel or each pixel. 10. The electroluminescent display device according to 10.

13. 11. The electroluminescent display device as described in 10 above, wherein the reflective electrode includes an inclined surface facing the light emitting layer in the non-microcavity region.

14. The electroluminescent display device of claim 10, wherein each of the plurality of microcavity regions has a length in the range of 1 μm to 5 μm in the horizontal direction of the substrate.

15. 14. The electroluminescent display device according to 13 above, wherein the reflective electrode includes at least two slopes toward the light emitting layer and one flat surface parallel to the light emitting layer in the microcavity region.

16. 16. The electroluminescent display device as described in 15, wherein the flat surface of the reflective electrode has a length of 1 μm to 5 μm in the microcavity region.

17. 16. The light emitting display device according to 15, wherein an angle formed between the inclined surface and the horizontal direction of the substrate is 20° to 70°.

18. A protective layer disposed on one side of the reflective electrode opposite to the first electrode;
Between the reflective electrode and the protective layer, a plurality of metal patterns arranged apart from each other,
11. The electroluminescent display device as described in 10 above, further comprising an overcoat layer disposed between the first electrode and the reflective electrode.

19. In the microcavity region, each of the plurality of metal patterns has a first surface in contact with the upper surface of the reflective electrode, a second surface in contact with the protective layer and having a larger area than the first surface, and a first surface and a second surface. 19. The light emitting display device according to 18, which includes a first slope and a second slope that connect two surfaces.

20. 19. The electroluminescent display device of 18, wherein a distance between two adjacent metal patterns is 0.5 μm to 2 μm.

21. 19. The electroluminescent display device according to 18, wherein the height of the plurality of metal patterns is 0.5 μm to 1 μm.

22. 20. The electroluminescent display device according to 19, wherein the first surface has a length of 1 μm to 5 μm.

23. 20. The electroluminescent display device according to 19, wherein an angle formed between the second surface and each of the first slope and the second slope is 20° to 70°.

100... Electroluminescence display device, 110... Substrate, 120... Thin film transistor, 121... Gate electrode, 122... Active layer, 123... Source electrode, 124... Drain electrode, 131... Gate insulating film, 132... Etch stopper, 133... Protective layer Reference numeral 136... Bank, 136a... Opening, 141... First electrode, 142... Light emitting layer, 143... Second electrode, 160... Overcoat layer, 160a... Opening part, RE... Reflective electrode, MP... Metal pattern, PP... Projection Section, D... Light emitting diode, EA... Light emitting region

Claims (23)

A thin film transistor arranged on the upper part of the substrate,
A protective layer disposed on the thin film transistor,
A plurality of metal patterns spaced apart from each other on the protective layer,
A reflective electrode that is arranged along the shape of the upper surfaces of the plurality of metal patterns and the protective layer and that includes a plurality of protrusions,
An overcoat layer disposed on the protective layer and the reflective electrode, the overcoat layer including an opening exposing the upper surface of each of the plurality of protrusions;
A first electrode disposed on the reflective electrode and the overcoat layer and electrically connected to the reflective electrode;
A light emitting layer disposed on the first electrode,
And a second electrode disposed on the light emitting layer. Each of the plurality of metal patterns has a first surface in contact with an upper surface of each of the plurality of protrusions, a second surface in contact with the protective layer and having a larger area than the first surface, and the first surface. The light emitting display device according to claim 1, further comprising a first slope and a second slope connecting the second slope and the second slope. The light emitting display device of claim 1, wherein a distance between the plurality of metal patterns is 0.5 μm to 2 μm. The light emitting display device of claim 1, wherein the height of the plurality of metal patterns is 0.5 μm to 1 μm. The light emitting display device of claim 2, wherein the first surface has a length of 1 μm to 5 μm. The light emitting display device of claim 2, wherein an angle formed by the second surface and the first slope and the second slope is 20° to 70°. The light emitting display device according to claim 2, wherein the first electrode, the light emitting layer, and the second electrode are arranged flat in a light emitting region. The light emitting display device of claim 1, wherein the reflective electrode is electrically connected to the thin film transistor. The light emitting display device of claim 1, wherein the first electrode is electrically connected to the thin film transistor. A substrate including one or more pixels,
Each of the pixels includes a second electrode and a reflective electrode, and a light emitting layer disposed between the second electrode and the reflective electrode, or a second electrode and a reflective electrode, the second electrode and the A light emitting structure including a light emitting layer disposed between reflective electrodes and a first electrode disposed between the light emitting layer and the reflective electrode;
A protective layer disposed on one side of the reflective electrode opposite to the light emitting layer ;
Between the reflective electrode and the protective layer, a plurality of metal patterns arranged apart from each other,
Each of the pixels includes a plurality of microcavity regions spaced apart from each other, and one or more non-microcavity regions disposed between the microcavity regions,
In the microcavity region, the combined thickness from the reflective electrode to the second electrode along the vertical direction of the light emitting structure is different from the combined thickness in the non-microcavity region,
The light emitting structure is configured to create a microcavity effect,
Each of the second electrode and the reflective electrode is formed to be flat in the microcavity region, and at least one of the second electrode and the reflective electrode has a non-flat surface in the non-microcavity region. Is formed to have
Alternatively, each of the first electrode, the second electrode, and the reflective electrode is formed to be flat in the microcavity region, and among the first electrode, the second electrode, and the reflective electrode, At least one is a light emitting display device having a non-flat surface in the non-microcavity region. In the microcavity region, the combined thickness from the reflective electrode to the second electrode along the vertical direction of the light emitting structure has a value smaller than the combined thickness in the non-microcavity region. 10. The electroluminescent display device according to 10. Each of the plurality of microcavity regions is formed to have a circular shape, a rectangular shape, a square shape, a rhombic shape, a hexagonal shape, or another polygonal shape which is arranged so as to be spaced apart from each other in one pixel or each pixel. The light emitting display device according to claim 10. The electroluminescent display device according to claim 10, wherein the reflective electrode includes a slope toward the light emitting layer in the non-microcavity region. The light emitting display device of claim 10, wherein each of the plurality of microcavity regions has a length in the range of 1 μm to 5 μm in the horizontal direction of the substrate. The electroluminescent display device according to claim 13, wherein the reflective electrode includes at least two slopes toward the light emitting layer and one flat surface parallel to the light emitting layer in the microcavity region. The electroluminescent display device of claim 15, wherein the flat surface of the reflective electrode in the microcavity region has a length of 1 μm to 5 μm. The light emitting display device of claim 15, wherein an angle formed between the inclined surface and the horizontal direction of the substrate is 20° to 70°. The electroluminescent display device of claim 10, further comprising an overcoat layer disposed between the first electrode and the reflective electrode. Each of the plurality of metal patterns has a first surface in contact with the upper surface of the reflective electrode in the microcavity region, a second surface in contact with the protective layer and having a larger area than the first surface, and The light emitting display device of claim 18, further comprising a first slope and a second slope connecting the first surface and the second surface. The electroluminescent display device of claim 18, wherein a distance between two adjacent metal patterns of the plurality of metal patterns is 0.5 μm to 2 μm. 19. The light emitting display device of claim 18, wherein the height of the plurality of metal patterns is 0.5 μm to 1 μm. The light emitting display device of claim 19, wherein the first surface has a length of 1 μm to 5 μm. The light emitting display device of claim 19, wherein an angle formed between the second surface and each of the first slope and the second slope is 20° to 70°.