KR102383928B1 - Electroluminescent Display Device - Google Patents

Abstract

According to the present invention, an overcoat layer having a microlens comprising a plurality of depressions and a plurality of protrusions is disposed on an electroluminescent display device. Accordingly, it is possible to increase the external luminous efficiency.
Furthermore, by arranging the barrier rib in the non-emissive area to increase the thickness of the overcoating layer in the light-emitting area, it is possible to prevent deterioration of image quality due to damage to the color filter pattern.
In addition, since a small amount of the overcoat layer forming material is used, price competitiveness can be improved.

Description

Electroluminescent Display Device

The present invention relates to an electroluminescent display, and more particularly, to an electroluminescent display including a micro lens array (MLA) having improved reliability.

Recently, a flat panel display having excellent characteristics such as reduction in thickness, weight reduction, and low power consumption has been widely developed and applied to various fields.

Among flat panel display devices, an electroluminescent display device injects electric charges into a light emitting layer formed between a cathode, which is an electron injection electrode, and an anode, which is a hole injection electrode, so that electrons and holes form excitons. It is a device that emits light by radiative recombination of excitons.

Such an electroluminescent display device can be formed on a flexible substrate such as plastic, and since it is a self-luminous type, the contrast ratio is large, and the response time is about several microseconds (㎲), so it is difficult to realize a moving image. It is easy, there is no limitation of the viewing angle, is stable even at low temperature, and it can be driven with a relatively low voltage of 5V to 15V of DC, so it has the advantage of easy manufacturing and design of the driving circuit.

1 is a schematic cross-sectional view of a general electroluminescent display device.

As shown in FIG. 1 , the electroluminescence display 1 includes a substrate 10 , a thin film transistor Tr positioned on the substrate 10 , and the thin film transistor Tr positioned on the substrate 10 and A light emitting diode D connected to Tr), a color filter pattern 50 may be provided under the light emitting diode D, and an encapsulation layer (not shown) may be positioned above 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 outputted to the outside through the first electrode 41 . .

In this way, the light emitted from the light emitting layer 42 passes through various components of the electroluminescent display 1 and comes out to the outside of the electroluminescent display 1 .

However, the optical waveguide mode composed of the surface plasmon component generated at the boundary between the metal and the light emitting layer 42 and the light emitting layer 42 inserted into both reflection layers occupies about 60 to 70% of the emitted light.

Accordingly, among the light emitted from the light emitting layer 42 , the light does not come out of the electroluminescent display device 1 and is trapped inside the electroluminescent display device 1 , so that the light extraction efficiency of the electroluminescent display device 1 is present. There is a problem with this degradation.

An object of the present invention is to provide an electroluminescent display device in which dark spots are prevented and light extraction efficiency is improved through an overcoat layer having a micro lens having improved reliability.

In order to achieve the above object, the present invention provides a substrate divided into a light-emitting area and a non-emission area, a red, blue, and green color filter pattern disposed on the substrate and disposed in the light-emitting area, and on the substrate at least two of the red, blue, and green color filter patterns and the red, blue, and green barrier rib patterns made of the same material and in the same layer as the red, blue, and green color filter patterns are stacked in the non-emissive region and an overcoat layer disposed on the color filter and the barrier rib, a first electrode disposed on the overcoat layer, a light emitting layer disposed on the first electrode, and a second electrode disposed on the light emitting layer display is provided.

In addition, the barrier rib pattern includes a first barrier rib pattern laminated on the substrate according to the stacking order, and a second barrier rib pattern laminated on the first barrier rib pattern, and the thickness of the first barrier rib pattern is 2um to It can be 3um.

Also, the thickness of the second barrier rib pattern may be 0.5 μm to 1 μm.

Here, it further includes a third barrier rib pattern laminated on the second barrier rib pattern, and the thickness of the third barrier rib pattern may be 0.5 μm to 1 μm.

In addition, each of the red, green, and blue barrier rib patterns may have a width of 3 μm to 5 μm.

In addition, the light emitting area includes first, second and third light emitting areas, the red color filter pattern is disposed in the first light emitting area, and the blue color filter pattern is disposed in the second light emitting area, The green color filter pattern may be disposed in the third light emitting area.

In addition, the light emitting area may further include a fourth light emitting area.

In addition, the overcoating layer may have a first thickness in the light-emitting region and a second thickness smaller than the first thickness in the non-emission region.

Here, the overcoating layer may have a morphology including a plurality of depressions and a plurality of protrusions in the light emitting region.

In addition, the first electrode, the light emitting layer, and the second electrode are disposed along the shape of the upper surface of the overcoat layer in the light emitting region, and include a plurality of depressions or a plurality of protrusions of the overcoat layer. can follow

In the present invention, it is possible to improve the light extraction efficiency by disposing an overcoat layer having a micro lens.

Furthermore, by forming the barrier rib in the non-emission area, it is possible to increase the thickness of the overcoat layer. Accordingly, it is possible to prevent the color filter pattern from being exposed and recognized as dark spots in the microlens forming process, thereby improving the reliability of the electroluminescent display device.

1 is a schematic cross-sectional view of a general electroluminescent display device.
2 is a circuit diagram illustrating one sub-pixel area of an electroluminescent display device according to an embodiment of the present invention.
3 is a schematic cross-sectional view of an electroluminescent display device according to a first embodiment of the present invention.
4 is a cross-sectional view schematically illustrating a micro lens provided in an overcoat layer of the electroluminescent display device according to the first embodiment of the present invention.
5 is a photograph showing a state in which the color filter pattern is damaged in the process of forming the microlens of the overcoat layer.
6 is a schematic cross-sectional view of an electroluminescent display device according to a second embodiment of the present invention.
7 is a plan view schematically illustrating a barrier rib formed in one pixel of an electroluminescent display device according to a second exemplary embodiment of the present invention.
FIG. 8 is a cross-sectional view taken along line VIII-VIII of FIG. 7 .

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

<First embodiment>

2 is a circuit diagram illustrating one sub-pixel area of an electroluminescent display device according to an embodiment of the present invention.

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

In more detail, 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 source 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 source electrode of the driving thin film transistor Td.

Looking at the image display operation of the electroluminescent display device, the switching thin film transistor Ts is turned on according to the gate signal applied through the gate line GL, and at this time, the data line DL The applied data signal is applied to the gate electrode of the driving thin film transistor Td and one electrode of the storage capacitor Cst through the switching thin film transistor Ts.

The driving thin film transistor Td is turned on according to the data signal to control the 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 transmitted through the driving thin film transistor Td.

That is, since the amount of current flowing through the light emitting diode D is proportional to the size of the data signal, and the intensity of light emitted from the light emitting diode D is proportional to the amount of current flowing through the light emitting diode D, the pixel area P ) indicates different gradations according to the size of the data signal, and as a result, the electroluminescence display displays an image.

The storage capacitor Cst maintains a charge corresponding to the data signal for one frame to keep the amount of current flowing through the light emitting diode D constant and to maintain the gradation displayed by the light emitting diode D constant. do

Meanwhile, other transistors and/or capacitors may be added to the sub-pixel region SP in addition to the switching and driving thin film transistors Ts and Td and the storage capacitor Cst.

3 is a cross-sectional view schematically showing an electroluminescent display device according to a first embodiment of the present invention, and FIG. 4 is a schematic view of a micro lens provided in an overcoat layer of the electroluminescent display device according to the first embodiment of the present invention. A cross-sectional view is shown.

As shown in FIG. 3 , the electroluminescent display device 100 according to the first embodiment of the present invention includes a substrate 110 , a thin film transistor 120 , a color filter pattern 150 , an overcoating layer 160 , and a thin film. It includes a light emitting diode (D) electrically connected to the transistor (120).

The electroluminescent display device 100 according to the first embodiment of the present invention exhibits a bottom emission type in which light from the light emitting layer 142 is output to the outside through the first electrode 141, but is limited thereto. it is not going to be

That is, in the electroluminescent display device 100 according to the first embodiment of the present invention, the color filter pattern 150 is located on the opposite side (upper side of D) of the substrate 110, so that the light from the light emitting layer 142 is It may be a top emission type that is output to the outside through the second electrode 143 .

In addition, in the case of a top emission type, a reflective electrode or a reflective layer may be further formed under the first electrode 141 . For example, the reflective electrode or the reflective layer may be formed of an aluminum-palladium-copper (APC) alloy. In this case, the second electrode 143 may have a relatively thin thickness to transmit light.

The electroluminescent display device 100 according to the first embodiment of the present invention is a thin film including a gate electrode 121 , an active layer 122 , a source electrode 123 , and a drain electrode 124 on a substrate 110 . A transistor 120 may be included.

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

In addition, an active layer 122 overlapping the gate electrode 121 may be disposed on the gate insulating layer 131 .

Also, an etch stopper 132 for protecting a channel region of the active layer 122 may be disposed on the active layer 122 .

In addition, a source electrode 123 and a drain electrode 124 contacting the active layer 122 may be disposed on the active layer 122 .

The electroluminescent display device to which embodiments of the present invention can be applied is not limited to FIG. 3 , and may further include a buffer layer disposed between the substrate 110 and the active layer 122 , and the etch stopper 132 is disposed it may not be

Meanwhile, for convenience of explanation, only the driving thin film transistor is shown among various thin film transistors that may be included in the electroluminescent display device 100 , and the gate electrode 121 is the source of the thin film transistor 120 based on the active layer 122 . It is described as having an inverted staggered structure or a bottom gate structure positioned opposite to the electrode 123 and the drain electrode 124 , but this is an example, and the gate electrode 121 is based on the active layer 122 . ) in which the source electrode 123 and the drain electrode 124 are positioned on the same side as the coplanar structure or the top gate structure of the thin film transistor may also be used.

A passivation layer 133 may be disposed on the drain electrode 124 and the source electrode 123 , and a color filter pattern 150 may be disposed on the passivation layer 133 .

Here, although the passivation layer 133 is illustrated as planarizing the upper portion of the thin film transistor 120 , the passivation layer 133 does not planarize the upper portion of the thin film transistor 120 , and may be disposed along the surface shape of the components located below. there is.

In addition, the color filter pattern 150 is for converting the color of the light emitted from the light emitting layer 142 , and may be one of a red color filter pattern, a green color filter pattern, and a blue color filter pattern.

Here, the color filter pattern 150 may be disposed on the protective layer 133 at a position corresponding to the emission area EA, or may be disposed only on a part of the emission area EA.

The light emitting area EA means an area in which the light emitting layer 142 emits light by the first electrode 141 and the second electrode 143 , and the color filter pattern 150 is disposed at a position corresponding to the light emitting area EA. Disposition means that the color filter pattern 150 is disposed so that light emitted from adjacent light emitting areas EA is mixed with each other to prevent blurring and ghosting.

For example, the color filter pattern 150 is disposed to overlap the emission area EA, and may have a size equal to or smaller than the emission area EA.

However, the arrangement position and size of the color filter pattern 150 are not only the size and position of the light emitting area EA, but also the distance between the color filter pattern 150 and the first electrode 141, the color filter pattern 150 and the The distance between the protrusion part PP and the depression part DP of the microlens provided in the overcoating layer 160, the distance between the light emitting area EA and the light emitting area EA, etc. may be variously determined.

Meanwhile, a pixel of the present invention may include one or more subpixels. For example, one pixel may include 2 to 4 sub-pixels.

Here, the sub-pixel means a unit in which a specific color filter pattern 150 is formed or the color filter pattern 150 is not formed and the light emitting diode D can emit a special color.

The color defined in the sub-pixel may include red (R), green (G), blue (B), and optionally white (W), but is not limited thereto.

Here, the overcoat layer 160 may be disposed on the color filter pattern 150 and the protective layer 133 .

Meanwhile, the protective layer 133 may be omitted. That is, the overcoat layer 160 may be disposed on the thin film transistor 120 .

In addition, although the color filter pattern 150 is illustrated as being disposed on the protective layer 133 , the present invention is not limited thereto, and the color filter pattern 150 may be disposed at an arbitrary position between the overcoat layer 160 and the substrate 110 . can be placed in

In particular, in order to improve light extraction efficiency in the electroluminescent display device 100 according to the first embodiment of the present invention, a micro lens ML may be provided in the overcoat layer 160 corresponding to the light emitting area EA. there is.

Here, the microlens ML may include a plurality of depressions DP and a plurality of protrusions PP, but is not limited thereto and may have various shapes.

For example, a microlens including a protrusion PP and a connector connecting the protrusions PP adjacent to each other may be formed on the overcoating layer 160 .

The overcoating layer 160 functions as a planarization layer in a region where the plurality of depressions DP and the plurality of protrusions PP are not disposed.

Here, each of the plurality of depressions DP may have various shapes, such as a hexagonal shape, a hemispherical shape, a semi-ellipsoidal shape, or a rectangular shape in plan view.

A light emitting diode D including a first electrode 141 , a light emitting layer 142 , and a second electrode 143 may be disposed on the overcoating layer 160 .

In addition, an insulating second protective layer (not shown) between the overcoating layer 160 and the first electrode 141 in order to block outgassing from the overcoating layer 160 from diffusing to the light emitting diode (D). ) can be placed.

That is, a second protective layer following the morphology of the plurality of depressions DP and the plurality of protrusions PP of the overcoat layer 160 may be disposed between the overcoat layer 160 and the first electrode 141 . .

Meanwhile, the first electrode 141 may be disposed on the overcoat layer 160 .

Here, the first electrode 141 may be an anode or a cathode for supplying either electrons or holes to the emission layer 142 .

A case in which the first electrode 141 of the electroluminescent display device according to the first embodiment of the present invention is an anode will be described as an example.

The first electrode 141 may be made of a conductive material having a relatively large work function value. For example, the first electrode 141 may be made of a transparent conductive material such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO).

The first electrode 141 may be connected to the source electrode 123 of the thin film transistor 120 through a contact hole formed in the overcoat layer 160 , and may be formed separately for each pixel area.

In the electroluminescent display device according to the first embodiment of the present invention, it has been described that the first electrode 141 is connected to the source electrode 123 using an N-type thin film transistor as an example, but the present invention is not limited thereto and the thin film transistor 120 is not limited thereto. ) is a P-type thin film transistor, the first electrode 141 may be connected to the drain electrode 124 .

Also, the first electrode 141 may be electrically connected to the light emitting layer 142 with a conductive material interposed therebetween.

Here, the first electrode 141 is disposed in a shape following the morphology of the surface of the overcoat layer 160 .

That is, the first electrode 141 may be disposed in a form that follows the morphology of the plurality of depressions DP and the plurality of protrusions PP of the overcoating layer 160 as it is.

In addition, a bank layer 136 may be disposed on the overcoat layer 160 and the first electrode 141 .

The bank layer 136 may include an opening 136a exposing the first electrode 141 .

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

Here, the plurality of depressions DP and the plurality of protrusions PP of the overcoat layer 160 may be disposed in the opening 136a of the bank layer 136 .

That is, since the plurality of depressions DP and the plurality of protrusions PP of the overcoat layer 160 are disposed to overlap the color filter 150 , the plurality of depressions DP of the overcoat layer 160 and the plurality of projections PP The protrusion PP may overlap the color filter 150 on the lower side and overlap the opening 136a of the bank layer 136 on the upper side.

In addition, the emission layer 142 may be disposed on the exposed first electrode 141 .

The light emitting layer 142 may have a structure in which a plurality of light emitting layers are stacked to emit white light (tandem white).

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 emits white light by mixing 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 this case, the color filter 150 may not be included.

Here, the light emitting material of the light emitting layer 142 may be an organic light emitting material or an inorganic light emitting material such as quantum dots.

In addition, the light emitting layer 142 may have a shape according to the morphology of the overcoating layer 160 .

A second electrode 143 for supplying either electrons or holes to the emission layer 142 may be disposed on the emission layer 142 .

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

A case in which the second electrode 143 of the electroluminescence display 100 according to the first embodiment of the present invention is a cathode will be described as an example.

The second electrode 143 is positioned on the entire surface of the display area and may be made of a conductive material having a relatively small work function value. For example, the second electrode 143 may be made of aluminum (Al), magnesium (Mg), silver (Ag), or an alloy thereof, but is not limited thereto.

Here, the second electrode 143 may have a shape according to the morphology of the overcoat layer 160 .

The first electrode 141 , the light emitting layer 142 , and the second electrode 143 form a light emitting diode D , and the light emitting diode D includes a plurality of depressions DP and a plurality of the overcoating layers 160 . The morphology of the protrusion PP of

In this way, the shape of the light emitting diode D can be realized by using the plurality of depressions DP and the plurality of projections PP of the overcoating layer 160 .

In this case, the overcoating layer 160 has a first thickness K1 (distance from the top surface of the color filter pattern 150 to the vertices of the plurality of protrusions PP of the overcoating layer 160) in the light emitting area EA) and the ratio has a second thickness K2 (distance from the top surface of the protective layer 133 to the flat top surface of the overcoat layer 160) in the light emitting area, and the thickness K1 of the light emitting area is the thickness K2 in the non-emission area formed smaller.

In addition, the overcoating layer 160 may have a third thickness K3 (distance from the top surface of the protective layer 133 to the vertices of the plurality of protrusions PP of the overcoating layer 160) in the light emitting area EA. , the third thickness K3 may be greater than or equal to the second thickness K2.

As described above, the electroluminescent display device 100 according to the first embodiment of the present invention includes an overcoating layer 160 having a microlens ML including a plurality of depressions DP and a plurality of protrusions PP. place it Accordingly, the light emitted from the light emitting layer 142 is totally reflected inside the first electrode 141 and the light emitting layer 142, and the light that cannot be extracted to the outside is advanced at an angle smaller than the total reflection critical angle, thereby increasing external luminous efficiency through multiple reflection. be able to increase

However, in order to form the depressions DP and the plurality of protrusions PP in the overcoating layer 160 corresponding to the light emitting area EA, photoresist is applied, patterned through a photolithography process, and then heat treatment is performed. , there is a problem in that the first thickness K1 of the overcoating layer 160 corresponding to the light emitting area EA is not sufficiently formed.

5 is a photograph showing a state in which the color filter pattern is damaged in the process of forming the microlens of the overcoat layer.

5, in the process of forming the depression DP of the overcoat layer 160, the first thickness K1 of the overcoat layer 160 is not thick enough, so the color filter pattern 150 disposed below is It may be exposed and damaged during the heat treatment process.

Such damage to the color filter pattern 150 is recognized as a dark spot in the image and causes deterioration of the image quality of the electroluminescent display device 100 .

Hereinafter, an electroluminescent display device capable of improving light extraction efficiency and preventing dark spots will be described in the second embodiment.

<Second embodiment>

Hereinafter, a detailed description of the same and similar configuration as that of the first embodiment may be omitted.

6 is a schematic cross-sectional view of an electroluminescent display device according to a second embodiment of the present invention.

As shown in FIG. 6 , the electroluminescence display 200 according to the second embodiment of the present invention includes a substrate 210 , a thin film transistor 220 , a color filter pattern 250 , an overcoat layer 260 , and a thin film. It includes a light emitting diode (D) electrically connected to the transistor (220).

The electroluminescent display device 200 according to the second embodiment of the present invention exhibits a bottom emission type in which light from the emission layer 242 is output to the outside through the first electrode 241, but is limited thereto. it is not going to be

That is, in the electroluminescent display device 200 according to the second embodiment of the present invention, the color filter pattern 250 is located on the opposite side of the substrate 210 , so that light from the emission layer 242 is transmitted to the second electrode 243 . It may be a top emission type that is output to the outside through .

In addition, in the case of a top emission type, a reflective electrode or a reflective layer may be further formed under the first electrode 241 . For example, the reflective electrode or the reflective layer may be formed of an aluminum-palladium-copper (APC) alloy. In this case, the second electrode 243 may have a relatively thin thickness so that light is transmitted.

The electroluminescent display 200 according to the second embodiment of the present invention is a thin film including a gate electrode 221 , an active layer 222 , a source electrode 223 , and a drain electrode 224 on a substrate 210 . A transistor 220 may be included.

Specifically, the gate electrode 221 and the gate insulating layer 231 of the thin film transistor 220 may be disposed on the first substrate 210 .

In addition, an active layer 222 overlapping the gate electrode 221 may be disposed on the gate insulating layer 231 .

Also, an etch stopper 232 for protecting a channel region of the active layer 222 may be disposed on the active layer 222 .

In addition, a source electrode 223 and a drain electrode 224 contacting the active layer 222 may be disposed on the active layer 222 .

The electroluminescent display device 200 to which embodiments of the present invention can be applied is not limited to FIG. 6 , and may further include a buffer layer disposed between the first substrate 210 and the active layer 222 , and an etch stopper 232 may not be placed.

Meanwhile, for convenience of explanation, only the driving thin film transistor among various thin film transistors that may be included in the electroluminescent display device 200 is illustrated, and the thin film transistor 220 has the gate electrode 221 as the source based on the active layer 222 . It is described as having an inverted staggered structure or a bottom gate structure positioned opposite to the electrode 223 and the drain electrode 224 , but this is an example, and the gate electrode 221 is based on the active layer 222 . ) in which the source electrode 223 and the drain electrode 224 are positioned on the same side as the coplanar structure or the top gate structure of the thin film transistor may also be used.

A passivation layer 233 may be disposed on the drain electrode 224 and the source electrode 223 , and a color filter pattern 250 may be disposed on the passivation layer 233 .

Here, although the passivation layer 233 is illustrated as planarizing the upper portion of the thin film transistor 220 , the passivation layer 233 does not planarize the upper portion of the thin film transistor 220 , and may be disposed along the surface shape of the components located below. there is.

In addition, the color filter pattern 250 is for converting the color of the light emitted from the light emitting layer 242 , and may be one of a red color filter pattern, a green color filter pattern, and a blue color filter pattern.

Here, the color filter pattern 250 may be disposed on the protective layer 233 at a position corresponding to the light emitting area EA, or may be disposed only on a part of the light emitting area EA.

The emission area EA means an area in which the emission layer 242 emits light by the first electrode 241 and the second electrode 243 , and the color filter pattern 250 is disposed at a position corresponding to the emission area EA. The disposition means that the color filter pattern 250 is disposed so that the light emitted from the adjacent light emitting areas EA is mixed with each other to prevent blurring and ghosting.

For example, the color filter pattern 250 is disposed to overlap the emission area EA, and may have a size equal to or smaller than the emission area EA.

However, the arrangement position and size of the color filter pattern 250 are not only the size and position of the light emitting area EA, but also the distance between the color filter pattern 250 and the first electrode 241 , the color filter pattern 250 and the The distance between the protrusion PP and the depression DP of the microlens provided in the overcoating layer 260 and the distance between the light emitting area EA and the light emitting area EA may be variously determined.

Meanwhile, a pixel of the present invention may include one or more subpixels. For example, one pixel may include 2 to 4 sub-pixels.

Here, the sub-pixel means a unit in which a specific color filter pattern 250 is formed or a color filter pattern 250 is not formed and the light emitting diode D can emit a special color.

The color defined in the sub-pixel may include red (R), green (G), blue (B), and optionally white (W), but is not limited thereto.

In particular, in the electroluminescent display device 200 according to the second embodiment of the present invention, the barrier rib 270 may be disposed in a non-emission area outside the color filter pattern 250 . That is, the barrier rib 270 may be formed in the non-emissive area to surround the light emitting area EA, and the barrier rib 270 may be formed only in a portion of the non-emissive area.

Here, the barrier rib 270 may include a red, blue, and green barrier rib pattern formed on the same material and the same layer as the red, blue, and green color filter pattern 250 .

Also, the barrier rib 270 may have a structure in which a plurality of barrier rib patterns are stacked. That is, at least two of the red, blue, and green barrier rib patterns may be stacked and formed.

The partition wall 270 will be described in more detail later.

Here, an overcoat layer 260 may be disposed on the color filter pattern 250 , the partition wall 270 , and the protective layer 233 .

Meanwhile, the protective layer 233 may be omitted. That is, the overcoating layer 260 may be directly disposed on the thin film transistor 220 .

In addition, although the color filter pattern 250 and the barrier rib 270 are illustrated as being disposed on the protective layer 233 , the present invention is not limited thereto, and the color filter pattern 250 and the barrier rib 270 are formed on the overcoat layer 260 . It may be disposed at any position between and the substrate 210 .

Here, the overcoating layer 260 of the light emitting area EA of the electroluminescent display device 200 of the second embodiment is formed in the non-emission region by the barrier ribs 270 of the electroluminescent display device of the first embodiment (100 in FIG. 3 ). ) of the light emitting area (EA of FIG. 4) can be formed to be thicker than the thickness (K1 of FIG. 4) of the overcoating layer (160 of FIG. 4).

That is, even with a smaller amount than the material for forming the overcoat layer (160 in FIG. 4) of the first embodiment, the first thickness (K1 in FIG. 4) of the overcoat layer (160 in FIG. 4) of the light emitting area (EA in FIG. 4) of the first embodiment ), the fourth thickness K4 of the overcoating layer 260 of the light emitting area EA of the second embodiment can be formed thicker.

Furthermore, when the barrier rib 270 is formed to surround the light emitting area EA, the fourth thickness K4 of the overcoating layer 260 corresponding to the light emitting area EA due to the entrapment effect by the barrier rib 270 . can be formed to be thicker than the first thickness K1 of the overcoating layer (160 in FIG. 4) corresponding to the light emitting area (EA in FIG. 4) of the first embodiment.

In addition, in order to improve light extraction efficiency in the electroluminescent display device 200 according to the second embodiment of the present invention, a micro lens ML may be provided in the overcoating layer 260 corresponding to the light emitting area EA. there is.

Here, the microlens ML may include a plurality of depressions DP and a plurality of protrusions PP, but is not limited thereto and may have various shapes.

For example, the microlens ML including the protrusion PP and the connecting portion connecting the protrusions PP adjacent to each other may be formed on the overcoating layer 260 .

The overcoating layer 260 functions as a planarization layer in a region where the plurality of depressions DP and the plurality of protrusions PP are not disposed. For example, the overcoating layer 260 of the non-emission region may have a flat top surface.

Here, each of the plurality of depressions DP may have various shapes, such as a hexagonal shape, a hemispherical shape, a semi-ellipsoidal shape, or a rectangular shape in plan view.

In addition, the pitch of the plurality of depressions DP may be 4 μm to 12 μm, but is not limited thereto.

In order to form the depressions DP and the plurality of protrusions PP in the overcoating layer 260 corresponding to the light emitting area EA, photoresist is applied, patterned through a photolithography process, and then heat treatment is performed. do.

Here, since the overcoating layer 260 of the electroluminescent display device 200 of the second embodiment is thicker in the region corresponding to the emission area EA than in the first embodiment, the overcoating layer corresponding to the emission region EA. It is possible to prevent the color filter pattern 250 from being exposed and damaged during the heat treatment process in the process of forming the recessed portion PP in the 260 .

In addition, a light emitting diode D including a first electrode 241 , a light emitting layer 242 , and a second electrode 243 may be disposed on the overcoating layer 260 .

In addition, an insulating second protective layer (not shown) between the overcoating layer 260 and the first electrode 241 in order to block outgassing from the overcoating layer 260 from diffusing to the light emitting diode (D). ) can be placed.

That is, a second protective layer following the morphology of the plurality of depressions DP and the plurality of protrusions PP of the overcoat layer 260 may be disposed between the overcoat layer 260 and the first electrode 241 . .

Meanwhile, the first electrode 241 may be disposed on the overcoating layer 260 .

Here, the first electrode 241 may be an anode or a cathode for supplying either electrons or holes to the emission layer 242 .

A case in which the first electrode 241 of the electroluminescent display device 200 according to the second embodiment of the present invention is an anode will be described as an example.

The first electrode 241 may be made of a conductive material having a relatively high work function value. For example, the first electrode 241 may be made of a transparent conductive material such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO).

The first electrode 241 may be connected to the source electrode 223 of the thin film transistor 220 through a contact hole formed in the overcoating layer 260 , and may be formed separately for each pixel area.

In the electroluminescent display device 200 according to the second embodiment of the present invention, it has been described that the first electrode 241 is connected to the source electrode 223 using an N-type thin film transistor as an example, but the present invention is not limited thereto. When the transistor 220 is a P-type thin film transistor, the first electrode 241 may be connected to the drain electrode 224 .

Also, the first electrode 241 may be electrically connected to the light emitting layer 242 with a conductive material interposed therebetween.

Here, the first electrode 241 is disposed following the morphology of the surface of the overcoat layer 260 .

That is, the first electrode 241 may be disposed in a form that follows the morphology of the plurality of depressions DP and the plurality of protrusions PP of the overcoating layer 260 as it is.

In addition, a bank layer 236 may be disposed on the overcoat layer 260 and the first electrode 241 .

The bank layer 236 may include an opening 236a exposing the first electrode 241 .

Here, the bank layer 236 may serve to distinguish between adjacent pixel (or sub-pixel) regions, and may be disposed between adjacent pixel (or sub-pixel) regions.

Here, the plurality of depressions DP and the plurality of protrusions PP of the overcoat layer 260 may be disposed in the opening 236a of the bank layer 236 .

That is, since the plurality of depressions DP and the plurality of protrusions PP of the overcoat layer 260 are disposed to overlap the color filter 250 , the plurality of depressions DP of the overcoat layer 260 and the plurality of projections PP The protrusion PP may overlap the color filter 250 at a lower portion and overlap the opening 236a of the bank layer 236 at an upper portion.

In addition, a light emitting layer 242 may be disposed on the first electrode 241 .

The light emitting layer 242 may have a structure in which a plurality of light emitting layers are stacked to emit white light (tandem white).

For example, the light emitting layer 242 may include a first light emitting layer emitting blue light and a second light emitting layer disposed on the first light emitting layer and emitting light of a color that becomes white by mixing with blue.

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

Meanwhile, the light emitting layer 242 may include only a light emitting layer that emits one of blue light, red light, and green light. In this case, the color filter 250 may not be included.

Here, the light emitting material of the light emitting layer 242 may be an organic light emitting material or an inorganic light emitting material such as quantum dots.

In addition, the emission layer 242 may have a shape according to the morphology of the overcoat layer 260 .

A second electrode 243 for supplying either electrons or holes to the emission layer 242 may be disposed on the emission layer 242 .

Here, the second electrode 243 may be an anode or a cathode.

A case in which the second electrode 243 of the electroluminescent display device 200 according to the second embodiment of the present invention is a cathode will be described as an example.

The second electrode 243 is positioned on the entire surface of the display area and may be made of a conductive material having a relatively small work function value. For example, the second electrode 243 may be made of aluminum (Al), magnesium (Mg), silver (Ag), or an alloy thereof, but is not limited thereto.

Here, the second electrode 243 may have a shape according to the morphology of the overcoat layer 260 .

The first electrode 241 , the light emitting layer 242 , and the second electrode 243 form a light emitting diode D, and the light emitting diode D includes a plurality of depressions DP of the overcoating layer 260 and a plurality of The morphology of the protrusion PP of

As described above, the shape of the light emitting diode D can be realized by using the plurality of depressions DP and the plurality of protrusions PP of the overcoating layer 260 of the overcoating layer 260 .

7 is a plan view schematically illustrating a partition wall formed in one pixel of an electroluminescent display device according to a second embodiment of the present invention, and FIG. 8 is a cross-sectional view taken along line VIII-VIII of FIG. 7 .

As shown in FIG. 7 , a pixel of the electroluminescent display 200 according to the second embodiment of the present invention may include one or more subpixels. For example, one pixel P may include first to fourth sub-pixels SP1 , SP2 , SP3 , and SP4 .

Here, each of the first to fourth sub-pixels SP1 , SP2 , SP3 , and SP4 corresponds to the emission area EA.

In addition, the non-emission area NEA may be formed to surround each of the first to fourth sub-pixels SP1 , SP2 , SP3 , and SP4 .

7 and 8 together, a color filter pattern is formed in the first to fourth emission areas EA1, EA2, EA3, and EA4 corresponding to the first to fourth sub-pixels SP1, SP2, SP3, and SP4. can be placed.

Here, the color filter pattern may be formed in all of the first to fourth light-emitting areas EA1, EA2, EA3, and EA4, and some of the first to fourth light-emitting areas EA1, EA2, EA3, and EA4. may be formed only in

For example, the red color filter pattern 250R may be formed in the first emission area EA1 , and the color filter patterns 250R, 250B, and 250G may not be formed in the second emission area EA2 .

Also, a blue color filter pattern 250B may be formed in the third emission area EA3 , and a green color filter pattern 250G may be formed in the fourth emission area EA4 .

Here, the width of the first light emitting area EA1 may be 44 um, the width of the second light emitting area EA2 may be 84 um, the width of the third light emitting area EA3 may be 62 um, and the fourth light emitting area EA2 may have a width of 62 um. The width of the area EA4 may be 44 μm, but this is only an example and is not limited thereto.

In addition, the red, blue, and green color filter patterns 250R, 250B, and 250G may all have the same thickness, or each of the red, blue, and green color filter patterns 250R, 250B, and 250G may have different thicknesses. there is.

For example, the red, blue, and green color filter patterns 250R, 250B, and 250G may all have the same thickness within the range of 2um to 3um, or may have different thicknesses, respectively.

In addition, the red, blue, and green color filter patterns 250R, 250B, and 250G are formed to overlap the light emitting area, but may be formed to have a smaller area than the light emitting area.

Here, the non-emission area NEA may be positioned to surround each of the first to fourth light emitting areas EA1 , EA2 , EA3 , and EA4 .

In addition, a barrier rib 270 may be formed in the non-emission area NEA. For example, the barrier rib 270 may be formed in all of the non-emission area NEA, and the barrier rib 270 may be formed only in a part of the non-emission area NEA.

In addition, heights of the barrier ribs 270 surrounding each of the first to fourth light emitting areas EA1 , EA2 , EA3 , and EA4 may be formed to be different from each other.

Here, the barrier rib 270 may include red, blue, and green barrier rib patterns 270R, 270B, and 270G formed on the same material and the same layer as the red, blue, and green color filter patterns 250R, 250B, and 250G. .

That is, the barrier rib 270 may have a structure in which a plurality of barrier rib patterns 270R, 270B, and 270G are stacked. For example, at least two of the red, blue, and green barrier rib patterns 270R, 270B, and 270G may be stacked.

For example, when the red, green, and blue color filter patterns 250R, 250G, and 250B are sequentially repeated, the barrier rib 270 formed in the non-emission area NEA includes the red barrier rib pattern 270R and The green barrier rib pattern 270G is laminated to form a double-layer barrier rib, and the red barrier rib pattern 270R, the green barrier rib pattern 270G, and the blue barrier rib pattern 270B are laminated to form the triple-layer barrier rib 270 . Also, the number and the stacking order of the barrier rib patterns 270R, 270B, and 270G may be variously modified.

Hereinafter, a case in which the triple layer barrier rib 270 is formed will be described as an example.

Here, the barrier rib patterns 270R, 270B, and 270G may be defined as a first barrier rib pattern 270a, a second barrier rib pattern 270b, and a third barrier rib pattern 270c according to the stacking order.

That is, the first barrier rib pattern 270a laminated on the upper surface of the protective layer ( 233 in FIG. 6 ), the second barrier rib pattern 270b and the second barrier rib pattern 270b laminated on the first barrier rib pattern 270a It may be defined as a third barrier rib pattern 270c stacked thereon.

Here, the thickness of the first barrier rib pattern 270a may be 2um to 3um.

For example, when the first barrier rib pattern 270a is formed of the red barrier rib pattern 270R, the thickness of the first barrier rib pattern 270a may be 3 μm, and the first barrier rib pattern 270a is formed of the blue barrier rib pattern ( 270B) or the green barrier rib pattern 270G, the thickness of the first barrier rib pattern 270a may be 2 μm. However, this is an example and is not limited thereto.

In addition, each of the second barrier rib pattern 270b and the third barrier rib pattern 270c stacked on the first barrier rib pattern 270a may have a thickness of 0.5 μm to 1 μm.

That is, even when each of the second barrier rib pattern 270b and the third barrier rib pattern 270c is formed of any of the red, blue, and green barrier rib patterns 270R, 270B, and 270G, they may be formed to a thickness of 0.5 μm to 1 μm.

For example, when the red, green, and blue barrier rib patterns 270R, 270G, and 270B are sequentially stacked, the red barrier rib pattern 270R as the first barrier rib pattern 270a may have a thickness of 3 μm, and the second, The thickness of each of the green and blue barrier rib patterns 270G and 270B that are the third barrier rib patterns 270b and 270c may be 0.5 to 1 μm.

In addition, when the blue, red, and green barrier rib patterns 270B, 270R, and 270G are sequentially stacked, the blue barrier rib pattern 270B, which is the first barrier rib pattern 270a, may have a thickness of 2 μm, and the second and third The thickness of each of the red and green barrier rib patterns 270R and 270G, which are the barrier rib patterns 270b and 270c, may be 0.5 to 1 μm.

In addition, when the green, red, and blue barrier rib patterns 270G, 270R, and 270B are sequentially stacked, the green barrier rib pattern 270G, which is the first barrier rib pattern 270a, may have a thickness of 2 μm, and the second and third The thickness of each of the red and blue barrier rib patterns 270R and 270B that are the barrier rib patterns 270b and 270c may be 0.5 to 1 μm.

However, this is only an example, and is not limited thereto. All of the first to third barrier rib patterns 270a, 270b, and 270c may be formed to have the same thickness.

Meanwhile, a width d of each of the red, green, and blue barrier rib patterns 270R, 270B, and 270G may be 3 μm to 5 μm, but is not limited thereto.

In particular, the red, blue, and green barrier rib patterns 270R, 270B, and 270G formed in the non-emission area NEA are the red, blue, and green color filter patterns 250R, 250B, 250G), since it can be formed using a forming process, an additional process is not required.

In addition, an overcoat layer 260 may be disposed on the passivation layer ( 233 of FIG. 6 ) including the color filter patterns 250R, 250B, and 250G and the barrier rib 270 .

Here, the fourth thickness K4 of the overcoating layer 260 of the light emitting area (EA of FIG. 6) of the electroluminescent display device (200 of FIG. 6) of the second embodiment (the overcoating layer from the upper surface of the color filter pattern 250) The distance from 260 to the apex of the plurality of protrusions PP) is the light emitting area (FIG. 4 EA) of the overcoat layer (160 in FIG. 4) can be formed to be thicker than the first thickness (K1 in FIG. 4).

That is, in the electroluminescent display device (200 in FIG. 6) according to the second embodiment of the present invention, even with a smaller amount than the amount of the forming material of the overcoat layer (160 in FIG. 4) of the first embodiment, It can be formed to be thicker than the first thickness (K1 in FIG. 4) of the overcoating layer (160 in FIG. 4) of the light emitting area (EA in FIG. 4).

Furthermore, when the barrier rib 270 is formed to surround the light emitting area (EA in FIG. 6 ), the overcoating layer 260 of the light emitting area (EA in FIG. 6 ) is formed by the trapping effect by the barrier rib 270 . 4 The thickness K4 can be formed to be thicker than the first thickness K1 of the overcoat layer (160 of FIG. 4 ) of the light emitting area (EA of FIG. 4) of the first embodiment.

For example, when the barrier rib 270 having a thickness of 3 μm is formed, the fourth thickness K4 of the overcoat layer 260 of the second embodiment than the first thickness K1 of the overcoat layer 160 of the first embodiment (160 in FIG. 4 ) ) can be raised by 1.5um.

Accordingly, it is possible to prevent the color filter pattern 250 from being exposed and damaged in the heat treatment process in the process of forming the recessed portion PP in the overcoating layer 260 corresponding to the light emitting area (EA in FIG. 6 ). .

On the other hand, the fifth thickness K5 of the overcoating layer 260 formed in the non-emission area NEA of the electroluminescent display device 200 of the second embodiment is 100 of the electroluminescence display device of the first embodiment ( 100 in FIG. 3 ). The overcoating layer formed in the non-emissive area (NEA of FIG. 4) of the overcoating layer (WP 2 of 160 in FIG. 4 is formed thinner than the second thickness K2, but the overcoating layer 260 formed in the non-emissive area NEA has a plurality of There is no problem because the microlens including the depressions DP and the plurality of protrusions PP is not formed.

That is, the overcoating layer 260 may have the shape of a plurality of depressions DP and a plurality of protrusions PP in the light emitting area (EA of FIG. 6 ), and may have a flat top surface in the non-emission area NEA.

In addition, the seventh thickness K7 (distance from the top surface of the protective layer 233 to the flat top surface of the overcoat layer 260) of the overcoat layer 260 formed in the non-emission area NEA is the sixth thickness K6. It may be formed to be equal to or thicker than (distance from the upper surface of the protective layer 233 to the apex of the protrusion PP of the overcoat layer 260 ).

On the other hand, the plurality of depressions DP and the plurality of protrusions PP of the overcoating layer 270 formed in the first to fourth light emitting regions EA1, EA2, EA3, and EA4 have the same width j1 and j2. However, the present invention is not limited thereto, and the widths of the plurality of depressions DP or the plurality of protrusions PP of the overcoating layer 270 in each of the first to fourth light emitting regions EA1, EA2, EA3, and EA4. (j1, j2) may be formed differently.

That is, in the first to fourth light emitting regions EA1, EA2, EA3, and EA4, as the region having the lowest luminous efficiency, the width j2 of the depression DP of the overcoat layer 270 or the maximum width of the protrusion PP ( By forming j1) narrow, the light extraction effect can be further improved in the light emitting region with low efficiency.

As described above, the electroluminescent display device 200 according to the second embodiment of the present invention includes an overcoating layer 260 having a microlens ML including a plurality of depressions DP and a plurality of protrusions PP. place it Accordingly, the light emitted from the light emitting layer 242 is totally reflected inside the first electrode 241 and the light emitting layer 242, and the light that is not extracted to the outside is advanced at an angle smaller than the total reflection critical angle, thereby increasing external luminous efficiency through multiple reflection. be able to increase

Furthermore, by arranging the barrier rib 260 in the non-emission area NEA to increase the thickness T1 of the overcoat layer 260 in the light emitting area, a depression in the overcoat layer 260 corresponding to the light emitting area EA ( It is possible to prevent exposure and damage to the color filter pattern 250 in the process of forming the PP), thereby preventing deterioration of image quality due to damage to the color filter pattern.

In addition, since the barrier rib 270 is made of the same material as the color filter pattern 250, an additional process is not required, and a smaller amount of the overcoat layer forming material is used than in the first embodiment, so that price competitiveness can be further increased. do.

Although the above has been described with reference to the preferred embodiment of the present invention, those skilled in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention described in the claims below You will understand that it can be done.

210: substrate 220: thin film transistor
221: gate electrode 222: active layer
223: source electrode 224: drain electrode
231: gate insulating film 232: etch stopper
233: protective layer 236: bank
241: first electrode 242: light emitting layer
243: second electrode 250: color filter pattern
260: overcoat layer 270: barrier rib
PP: protrusion DP: depression
D: light emitting diode EA: light emitting area
K4: fourth thickness

Claims (12)

a substrate divided into a light-emitting area and a non-emission area;
first to third color filter patterns disposed on the substrate and disposed in the light emitting area;
It is positioned on the substrate, has a shape surrounding the light emitting area in the non-emission area, and includes at least two of the first to third barrier rib patterns made of the same layer and the same material as the first to third color filter patterns. laminated bulkheads;
an overcoating layer disposed on the first to third color filter patterns and the barrier rib and including a plurality of depressions and a plurality of protrusions in the light emitting region;
a first electrode disposed on the overcoat layer;
a light emitting layer disposed on the first electrode;
a second electrode disposed on the light emitting layer;
includes,
The height of the barrier rib is higher than that of the first to third color filter patterns.
The method of claim 1,
The first color filter pattern is a red color filter pattern, the second color filter pattern is a blue color filter pattern, and the third color filter pattern is a green color filter pattern.
The method of claim 1,
The partition wall is
the first barrier rib pattern laminated on the substrate according to the lamination order;
The second barrier rib pattern laminated on the first barrier rib pattern
includes,
The first barrier rib pattern has a first thickness, and the second barrier rib pattern has a second thickness smaller than the first thickness.
4. The method of claim 3,
The electroluminescent display device further comprising the third barrier rib pattern laminated on the second barrier rib pattern, wherein the third barrier rib pattern has a third thickness smaller than the first thickness.
According to claim 1,
the first barrier rib pattern is a red barrier rib pattern, the second barrier rib pattern is a green barrier rib pattern, the third barrier rib pattern is a blue barrier rib pattern,
The red, green, and blue barrier rib patterns each have a width of 3 μm to 5 μm.
The method of claim 1,
The light emitting region includes first, second and third light emitting regions,
A red color filter pattern is disposed in the first emission region, a blue color filter pattern is disposed in the second emission region, and a green color filter pattern is disposed in the third emission region.
7. The method of claim 6,
The light emitting area further includes a fourth light emitting area, and the electroluminescent display device further comprising a fourth barrier rib pattern having a shape surrounding the fourth light emitting area.
8. The method of claim 7,
The first to fourth barrier rib patterns surrounding each of the first to fourth light emitting regions have different heights from each other.
The method of claim 1,
The overcoat layer has a first thickness corresponding to the first to third color filter patterns, and the first thickness is greater than a second thickness corresponding to the partition wall.
8. The method of claim 7,
In each of the first to fourth light emitting regions, the plurality of depressions or the plurality of protrusions of the overcoat layer have different widths.
The method of claim 1,
The first electrode, the light emitting layer, and the second electrode are disposed along the shape of the upper surface of the overcoat layer in the light emitting region, and follow a morphology including a plurality of depressions or a plurality of protrusions of the overcoat layer. electroluminescent display. The method of claim 1,
The overcoat layer corresponds to the barrier rib and has a flat top surface.

Images