KR20090021709A - Light emitting device and fabrication method for the same - Google Patents

Abstract

An electroluminescent device and a manufacturing method thereof are provided to improve contrast of an image by preventing lateral direction dispersion of a light emitted in an organic layer. An electroluminescent device(100) comprises a substrate(101), an insulated film(160), a first electrode(170), an organic layer(190), and a second electrode(195). The substrate includes a thin film transistor part. The insulated film is formed on the substrate, and has a via hole(163) and a concave part(R). The via hole exposes the thin film transistor part. The first electrode is connected to the thin film transistor part through the via hole, and is formed on the concave part. The organic layer is formed on the first electrode. Width between a highest end part of the insulated film and a lowest end part of the insulated film is 0.8um ~ 2.0um. Width between a highest end part of the concave part and a lowest end part of the concave part is 0.1um ~ 0.5um.

Description

Electroluminescent device and method of manufacturing the same {Light emitting device and Fabrication method for the same}

The present invention relates to a display, and more particularly to an electroluminescent device and a method of manufacturing the same.

Recently, as the size of the display device increases, the demand for a flat display device having less space occupancy is increasing. As one of the flat display devices, an electroluminescent device is attracting attention.

In particular, the electroluminescent device emits light when the excitons generated by combining the injected electrons and holes from the electron injection hole and the hole injection electrode into the light emitting part fall from the excited state to the ground state. to be.

The electroluminescent device has excellent features such as wide viewing angle, high-speed response and high contrast, so it can be used as a pixel of graphic display, pixel of television image display or surface light source, and is suitable for next-generation flat panel display because it is thin, light and has good color. Element.

Electroluminescent devices are manufactured in a structure in which electrodes and light emitting layers are laminated on an insulating film, generally referred to as a planarization film. In addition to going straight, light can also be scattered on either side. Therefore, as described above, a lot of researches have been conducted to compensate for the poor light efficiency and mixing with light of adjacent subpixels.

The problem to be solved by the present invention is to provide an electroluminescent device and a method for manufacturing the same, which can enhance the luminous efficiency of light and increase the contrast.

Technical problems to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

An electroluminescent device according to an embodiment of the present invention is a substrate including a thin film transistor portion, an insulating film having a via hole and a recess formed on the substrate and exposing the thin film transistor portion, connected to the thin film transistor portion through the via hole and on the recess It may include a first electrode formed, an organic layer formed on the first electrode and a second electrode formed on the organic layer.

In addition, the width between the uppermost end and the lowermost end of the insulating film may be 0.8 μm to 2 μm.

In addition, the width between the uppermost end and the lowermost end of the recess may be 0.1 μm to 0.5 μm.

In addition, the ratio between the width between the top and bottom of the recess and the width of the top and bottom of the insulating film may be 1: 1.6 to 1:20.

In addition, the first electrode may be an anode electrode, and the second electrode may be a cathode electrode.

In addition, the first electrode may include a reflective electrode connected to the thin film transistor unit through a via hole and a first transparent electrode formed on the reflective electrode.

In addition, the first electrode may include a second transparent electrode connected to the thin film transistor through a via hole, a reflective electrode sequentially formed on the second transparent electrode, and a first transparent electrode.

In addition, the material of the reflective electrode may be any one of aluminum, silver, and nickel.

In addition, the sum of the widths of the recesses may be greater than the sum of the widths of the insulating films on which the recesses are not formed in the light emitting region.

Further, the ratio of the sum of the widths of the recesses to the sum of the widths of the insulating films on which the recesses are not formed in the light emitting region may be 3: 1 to 5: 1.

In the electroluminescent device for increasing the light emission efficiency of the light according to another embodiment of the present invention, the electroluminescent device comprises an insulating film formed with a recess and an organic layer formed on the recess, the light emitted from the organic layer is focused for each pixel Can be.

A method of manufacturing an electroluminescent device according to an embodiment of the present invention comprises the steps of forming a thin film transistor portion on a substrate, forming an insulating film formed with a recess on the substrate and the thin film transistor portion, a via hole exposing the thin film transistor portion on the insulating film And forming a reflective electrode formed on the recess, the reflective electrode connected to the thin film transistor through the via hole, and sequentially forming a first electrode, an organic layer, and a second electrode on the reflective electrode. have.

In addition, the width between the uppermost end and the lowermost end of the insulating film may be 0.8 μm to 2 μm.

In addition, the width between the uppermost end and the lowermost end of the recess may be 0.1 μm to 0.5 μm.

In addition, the ratio of the width between the top and bottom ends of the recess and the width between the top and bottom ends of the insulating film may be 1: 1.6 to 1:20.

In addition, the first electrode may be an anode electrode, and the second electrode may be a cathode electrode.

In addition, the first electrode may include a reflective electrode connected to the thin film transistor unit through a via hole and a first transparent electrode formed on the reflective electrode.

In addition, the first electrode may include a second transparent electrode connected to the thin film transistor through a via hole, a reflective electrode sequentially formed on the second transparent electrode, and a first transparent electrode.

In addition, the material of the reflective electrode may be any one of aluminum, silver, and nickel.

In addition, the sum of the widths of the recesses may be greater than the sum of the widths of the insulating films on which the recesses are not formed in the light emitting region.

Further, the ratio of the sum of the widths of the recesses to the sum of the widths of the insulating films on which the recesses are not formed in the light emitting region may be 3: 1 to 5: 1.

The electroluminescent device according to an embodiment of the present invention has the effect of increasing the luminous efficiency of the light and the contrast of the image.

Hereinafter, an electroluminescent device and a method of manufacturing the same according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

An embodiment of the present invention will be described with reference to the organic electroluminescent device having the light emitting layer as an organic material among the electroluminescent devices, but is not limited thereto. That is, the present invention can be applied to other display devices such as inorganic electroluminescent devices.

1A to 1E are cross-sectional views of an electroluminescent device 100 according to an embodiment of the present invention.

Referring to FIG. 1A, the electroluminescent device 100 may include a substrate 101, a buffer layer 105, a thin film transistor unit, first to fourth insulating layers, a first electrode 170, an organic layer 190, and a second electrode ( 195, a reflective electrode 165, and the like.

The substrate 101 may be made of a transparent glass or plastic material. The buffer layer 105 may be formed on the substrate 101. The buffer layer 105 may be formed to prevent impurities from the substrate 101 from flowing into the device during the manufacturing of the electroluminescent device 100. The buffer layer 105 may use silicon nitride (SiNx), silicon oxide (SiO ₂ ), or silicon oxynitride film (SiOxNx).

The thin film transistor unit may include a gate electrode 130, a source electrode 150a, a drain electrode 150b, and a semiconductor layer 110. The thin film transistor unit illustrated in this drawing has a coplanar structure in which the gate electrode 130 has a top-gate on the semiconductor layer 110. In an embodiment of the present invention, a thin film transistor unit having the above-described structure will be described, but a thin film transistor unit having another structure may be used.

The semiconductor layer 110 may be formed on the buffer layer 105. The semiconductor layer 110 may form a channel in the thin film transistor unit, and may be formed of an amorphous silicon (a-silicon) or a polysilicon (p-silicon) material.

The first insulating layer 120, which may be referred to as a gate insulating layer, may be formed on the buffer layer 105 on which the semiconductor layer 110 is formed. The first insulating layer 120 may be formed of silicon oxide or silicon nitride, but is not limited thereto. The gate insulating layer may insulate the gate electrode 130, the source electrode 150a and the drain electrode 150b described later.

The gate electrode 130 may be formed on the first insulating layer 120 at a position corresponding to the semiconductor layer 110. The gate electrode 130 may turn the thin film transistor on / off using a data voltage provided from a data line (not shown).

A second insulating layer 140, which may be referred to as an interlayer insulating layer, may be formed on the first insulating layer 120 on which the gate electrode 130 is formed. The second insulating layer 140 may also be formed of silicon oxide or silicon nitride, but is not limited thereto.

A contact hole 135 may be formed in the first insulating layer 120 and the second insulating layer 140 to form a source electrode 150a and a drain electrode 150b connected to the semiconductor layer 110. The source electrode 150a and the drain electrode 150b may be connected to the semiconductor layer 110 through one contact hole 135 to protrude above the second insulating layer 140.

The gate electrode 130, the source electrode 150a, and the drain electrode 150b include chromium (Cr), aluminum (Al), molybdenum (Mo), silver (Ag), copper (Cu), titanium (Ti), and tantalum ( Ta) or an alloy thereof or the like may be formed in a laminated structure of at least one layer or more.

The third insulating layer 160 may be formed on the substrate 101 on which the thin film transistor unit, the first to second insulating layers 140, and the buffer layer 105 are formed. The third insulating layer 160 may have a via hole 163 exposing a portion of the thin film transistor portion, in detail, a portion of the drain electrode 150b, so as to be formed on the thin film transistor portion and the second insulating layer 140. The third insulating layer 160 may be formed to protect the thin film transistor and to insulate the elements or the signal lines. In addition, it may be formed of any one material selected from benzocyclobutene, polyimide and acrylic resin, but is not limited thereto.

1B to 1D, a parabolic concave portion R may be formed on the third insulating layer 160 of the emission region A of the electroluminescent device 100. As will be described later, an organic layer 190 for generating each electrode and light is formed on the recess, and the above-described electrode and the organic layer 190 may also have a parabolic shape struck down like the shape of the recess.

When the electroluminescent device 100 operates through the above-described structure, the third insulating layer 160 and the organic layer 190 including the recesses when the light is generated in the organic layer 190 provided for each subpixel are subpixels. Since it plays a role of collecting light each time, it is possible to maximize luminous efficiency and to prevent the generation of light spreading from both sides, thereby increasing the contrast of the image.

A plurality of recesses in the light emitting regions A ′ and A ″ of FIGS. 1C to 1D may be formed on the light emitting regions of the third insulating layer 160. An upper portion of the third insulating layer 160 on which the recess is not formed in the emission area may have a flat or convex shape.

In the drawing, the number of recesses on the light emitting area is about three, but is not limited thereto.

Here, the sum of the widths of the recesses R1 + R2 + R3 may be larger than the width L1 + L2 of the third insulating layer 160 where the recesses are not formed in the emission regions A ′ and A ″.

Further, the ratio of the sum of the widths of the recesses (R1 + R2 + R3) and the width (L1 + L2) of the third insulating film 160 where the recesses are not formed on the light emitting regions A 'and A' 'is 3: 1. To 5: 1.

If the ratio of the sum of the widths of the recesses (R1 + R2 + R3) and the width (L1 + L2) of the third insulating film on which the recesses are not formed on the light emitting regions A 'and A' 'is 3: 1 or more, each sub When the organic layer 190 provided for each pixel generates light, the third insulating layer 160 including the recess and the organic layer 190 collect light for each subpixel, thereby maximizing luminous efficiency. Since it is possible to prevent the light from spreading out, the contrast of the image can be increased, and if it is 5: 1 or less, the third insulating film 160, the first electrode 170, the organic layer 190, and the second electrode ( The process of depositing 195 can be facilitated.

Here, the light emitting regions A, A ', and A' 'are shown in the drawings even parts which do not actually emit light for clearer and easier representation. If the light emitting region is clearly expressed, it may be the R portion where the recess is formed in A, and may be the R1 to R3 and the L1 to L2 portions in A 'and A' '.

Referring back to FIG. 1, in general, the width of the third insulating layer 160 may be 0.8 μm to 2 μm. The width between the top and bottom of the concave portion according to an embodiment of the present invention may be 0.1μm to 0.5μm.

If the width of the concave portion is less than 0.1μm, the effect of increasing the above-mentioned luminous efficiency and contrast is very low. If the width of the concave portion is larger than 0.5μm, the light emitted from the organic layer 190 is bent into the light emitting region A. This can cause a negative effect of light scattering.

The ratio of the width between the uppermost end and the lowermost end of the concave portion and the width of the third insulating layer 160 may be 1: 1.6 to 1:20. When the electroluminescent device 100 emits light in this range, it may have high luminous efficiency and contrast. The width value of the recess and the ratio of the width of the recess to the width of the third insulating layer 160 may vary depending on the width of the third insulating layer 160, the organic layer 190, and an electrode to be described later.

Referring to FIG. 1E, a first electrode connected to the drain electrode 150b of the TFT may be formed through the via hole 163.

The first electrode 170 is formed on the third insulating layer 160, and is formed on the reflective electrode 170b connected to the thin film transistor unit through the via hole 163 and the first electrode formed on the reflective electrode 170b. It may include a transparent electrode 170a. The reflective electrode 170b may be electrically connected to the drain electrode 150b of the thin film transistor unit, and the first transparent electrode 170a may be electrically connected to the reflective electrode 170b.

The reflective electrode 170b is the first electrode when the organic layer 190 does not emit light onto the second electrode 195, which will be described later, in the top-emission structure and the light is emitted onto the first electrode 170. Located at the bottom of 170, the light emitted from the organic layer 190 may be emitted to the second electrode 195. The reflective electrode 170b may be formed of any one of silver (Ag), aluminum (Al), or nickel (Ni), which is a material having good reflectivity, but is not limited thereto.

In addition, the first electrode 170 is formed on the third insulating layer 160, and is connected to the drain electrode 150b of the thin film transistor unit through the via hole 163 and the second transparent electrode. The reflective electrode 170b and the first transparent electrode 170a formed on the electrode 170c may be included.

When the second transparent electrode 170c is further formed below the reflective electrode 170b than when the first electrode 170 is formed of the reflective electrode 170b and the first transparent electrode 170a, the thin film transistor portion and The contact ability can be improved when connected. The first transparent electrode 170a and the second transparent electrode 170c may be formed of either ITO or IZO, but are not limited thereto.

The first electrode 170 may be an anode electrode. The first electrode 170 may receive a voltage from the reflective electrode 165 to provide holes to the organic layer 190 to be described later. The first electrode 170 may be formed of any one of indium tin oxide (ITO) or indium zinc oxide (IZO). The materials have both transparent and electrically conductive properties. In the top emission electroluminescent device 100 according to the structure of the present invention, when the light generated from the organic layer 190 exits to the first electrode 170, the reflective electrode 165 under the first electrode 170 is the light. May be exported to the second electrode 195 again.

The fourth insulating layer 180, which is referred to as a pixel definition layer, is formed on the third insulating layer 160 and the first electrode 170 and exposes a portion of the first electrode 170 to define an emission area A. 185 may be formed. The fourth insulating layer 180 may be formed of any one material selected from benzocyclobutene, polyimide, and acrylic resin, but is not limited thereto.

The organic layer 190 may be formed on the first electrode 170 to receive holes from the first electrode 170. A hole injection layer and a hole transport layer may be sequentially formed between the organic layer 190 and the first electrode 170. The organic layer 190 may have a parabolic shape that is struck down depending on the shape of the recess formed in the third insulating layer 160.

Through the above structure, when the electroluminescent device 100 operates, the third insulating layer 160 and the organic layer 190 including the recesses when generating light from the organic layer 190 provided for each subpixel are subpixels. Since it plays a role of collecting light each time, it is possible to maximize luminous efficiency and to prevent the generation of light spreading from both sides, thereby increasing the contrast of the image.

The second electrode 195 may be formed to face the first electrode 170 with the organic layer 190 interposed therebetween. The second electrode 195 may be a cathode electrode. Since the cathode electrode is also formed on the organic layer 190, it may have the same concave portion as the organic layer 190. An electron transport layer and an electron injection layer may be sequentially formed between the organic layer 190 and the second electrode 195. The organic layer 190 receives holes and electrons from the first electrode 170 and the second electrode 195 described above to generate excitons to emit light to the front to display an image.

Referring to FIG. 1C, a transparent electrode 163 connected to the drain electrode 150b of the TFT may be formed through the via hole 163. The transparent electrode 163 is formed of ITO, IZO, or the like. As shown in FIG. 1A, the transparent electrode 163 has better contact capability when the transparent electrode is connected to the thin film transistor unit than when the reflective electrode 165 is connected to the thin film transistor unit.

The reflective electrode 165 is formed on the transparent electrode 163. The reflective electrode 165 has a top-emission structure in which the organic layer 190 does not emit light onto the second electrode 195 and the first electrode. When the light exits from the light source 170, the light emitted from the organic layer 190 may be emitted to the second electrode 195 by being positioned under the first electrode 170.

The first electrode 170 may be formed on the reflective electrode 165 described above. The first electrode 170 may be formed on the reflective electrode 165 to be electrically connected to the connection electrode. In an embodiment of the present invention, the transparent electrode 163, the reflective electrode 165, and the first electrode 170 are separately described, but in fact, the first electrode 170, the reflective electrode 165, and the transparent electrode are one. It may be referred to as the first electrode 170 by treating it as an electrode of.

2A to 2E are views illustrating a method of manufacturing the electroluminescent device 200 according to an embodiment of the present invention.

Materials and features of the components constituting the device described below are the same as the contents of the electroluminescent device 200 described above. Therefore, the above description will be omitted while using the manufacturing method of the electroluminescent device 200 according to the features of the present invention.

Referring to FIG. 2A, a thin film transistor unit including a gate electrode 230, a source electrode 250a, a drain electrode 250b, an active layer, a first insulating film 220, and a second insulating film 240 on a substrate 201. ).

Specifically, the buffer layer 205 is formed on the substrate 201. The buffer layer 205 may be formed to prevent impurities from the substrate 201 from flowing into the device.

After sequentially forming the semiconductor layer 210 and the first insulating layer 220 on the substrate 201 where the buffer layer 205 is formed, the active layer is formed by photolithography the semiconductor layer 210. The active layer may be formed of amorphous silicon or polysilicon material.

The gate electrode 230 stacked on at least one layer is formed on the substrate 201 having the above-described process by forming a gate metal film and then photoetching the gate metal film.

Next, a second insulating layer 240 is formed on the gate electrode 230 and the first insulating layer 220, and then a contact hole 235 is formed to form a source electrode 250a connected to the semiconductor layer 210. The drain electrode 250b is formed in at least one layer.

Referring to FIGS. 2B to 2C, a third insulating layer having recesses is formed on the substrate 201 on which the thin film transistor unit and the first to second insulating layers 240 are formed. The concave portion is made in a parabolic shape which is struck down only in the light emitting region A in the subpixel units.

An organic layer 290 for generating each electrode and light is formed on the recess, and the above-described electrode and the organic layer 290 may also have a parabolic shape struck down like the shape of the recess.

When the electroluminescent device 200 is operated through the above-described structure, the third insulating film 260 and the organic layer 290 including the recesses when the light is generated in the organic layer 290 provided for each sub-pixel are sub-pixels. Since it plays a role of collecting light each time, it is possible to maximize luminous efficiency and to prevent the generation of light spreading from both sides, thereby increasing the contrast of the image.

In general, the width of the third insulating layer 260 may be 0.8 μm to 2 μm. The width between the top and bottom of the concave portion according to an embodiment of the present invention may be 0.1μm to 0.5μm.

If the width of the concave portion is less than 0.1μm, the effect of increasing the above-mentioned luminous efficiency and contrast is very low. If the width of the concave portion is higher than 0.5μm, the light emitted from the organic layer 290 is bent into the light emitting region A. This can cause a negative effect of light scattering.

The ratio of the width between the upper end and the lower end of the concave portion and the width of the third insulating layer may be 1: 1.6 to 1:20. When the electroluminescent device 200 emits light in this range, it may have high luminous efficiency and contrast. The width value of the recess and the ratio of the width of the recess to the width of the third insulating layer may vary depending on the width of the third insulating layer 260, the organic layer 290, and an electrode to be described later.

The via hole 263 is formed in the third insulating layer so that the first electrode 270 can be connected to the drain electrode 250b of the thin film transistor unit.

2D to 2E, a first electrode 370 is formed on the substrate 301 having the above-described structure so as to be connected to the thin film transistor unit.

The first electrode 270 may be an anode electrode. The first electrode 270 may receive a voltage from the thin film transistor unit to provide holes to the organic layer 290 to be described later.

The fourth insulating layer 280 is formed on the third insulating layer 260 and the first electrode 270, and forms an opening 285 defining a light emitting area A by exposing a portion of the first electrode 270. Done.

Next, the organic layer 290 is formed on the first electrode 270. The organic layer 290 may have a parabolic shape that is struck down according to the shape of the recess formed in the third insulating layer 260.

Through the above structure, when the electroluminescent device 200 is operated, the third insulating layer 260 and the organic layer 290 including the recesses when the light is generated in the organic layer 290 provided for each subpixel serve as the sub-layers. As it collects light for each pixel, it is possible to maximize luminous efficiency and to prevent generation of light spreading from side to side, thereby increasing the contrast of the image.

The second electrode 295 is formed to face the first electrode 270 with the organic layer 290 therebetween. The second electrode 295 may be a cathode electrode. Since the cathode electrode is also formed on the organic layer 290, it may have the same concave portion as the organic layer 290.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains can understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. will be. Therefore, the above-described embodiments are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the appended claims rather than the detailed description, and the meaning and scope of the claims and All changes or modifications derived from the equivalent concept should be interpreted as being included in the scope of the present invention.

1A to 1E are cross-sectional views of an electroluminescent device according to an embodiment of the present invention.

2A to 2E are views illustrating a method of manufacturing an electroluminescent device according to an embodiment of the present invention.

(Explanation of symbols for the main parts of the drawing)

R: recess 160: insulating film (third insulating film)

Claims (21)

A substrate including a thin film transistor unit; An insulating layer formed on the substrate and having a via hole and a concave portion exposing the thin film transistor portion; A first electrode connected to the thin film transistor part through the via hole and formed on the concave part; An organic layer formed on the first electrode; And A second electrode formed on the organic layer; Electroluminescent device comprising a. The method of claim 1, And a width between the uppermost end and the lowermost end of the insulating film is 0.8 μm to 2 μm. The method of claim 1, The width between the upper end and the lowest end of the concave portion is an electroluminescent device, characterized in that 0.1μm to 0.5μm. The method of claim 1, And the ratio of the width between the top and bottom ends of the recess and the width between the top and bottom ends of the insulating film is 1: 1.6 to 1:20. The method of claim 1, And the first electrode is an anode electrode and the second electrode is a cathode electrode. The method of claim 1, The first electrode includes a reflective electrode connected to the thin film transistor unit through the via hole and a first transparent electrode formed on the reflective electrode. The method of claim 1, The first electrode includes a second transparent electrode connected to the thin film transistor through the via hole, a reflective electrode sequentially formed on the second transparent electrode, and a first transparent electrode. The method according to claim 6 or 7, The material of the reflective electrode is any one of aluminum, silver, nickel. The method of claim 1, The sum of the widths of the recesses is greater than the sum of the widths of the insulating films on which the recesses are not formed in the light emitting area. The method of claim 9, And a ratio of the sum of the widths of the recesses and the sum of the widths of the insulating films in which the recesses are not formed in the light emitting region is 3: 1 to 5: 1. In the electroluminescent device to increase the luminous efficiency of light, The electroluminescent device includes an insulating layer having a recess and an organic layer formed on the recess, and the light emitted from the organic layer is focused for each pixel. Forming a thin film transistor unit on the substrate; Forming an insulating film on which the recess is formed on the substrate and the thin film transistor portion; Forming a via hole exposing the thin film transistor on the insulating layer; Forming a first electrode formed on the concave portion and connected to the thin film transistor portion through the via hole; And Sequentially forming an organic layer and a second electrode on the first electrode; Method of manufacturing an electroluminescent device comprising a. The method of claim 12, The width between the upper end and the lower end of the insulating film is a manufacturing method of the electroluminescent device, characterized in that 0.8μm to 2μm. The method of claim 12, The width between the upper end and the lower end of the concave portion is a manufacturing method of the electroluminescent device, characterized in that 0.1μm to 0.5μm. The method of claim 12, The ratio of the width between the upper end and the lower end of the concave portion and the width between the upper end and the lower end of the insulating film is 1: 1.6 to 1:20. The method of claim 12, The first electrode is an anode electrode, the second electrode is a manufacturing method of the electroluminescent device, characterized in that the cathode electrode. The method of claim 12, The first electrode may include a reflective electrode connected to the thin film transistor unit through the via hole, and a first transparent electrode formed on the reflective electrode. The method of claim 12, The first electrode includes a second transparent electrode connected to the thin film transistor through the via hole, a reflective electrode sequentially formed on the second transparent electrode, and a first transparent electrode. Manufacturing method. The method of claim 18 or 19, The reflective electrode may be made of any one of aluminum, silver, and nickel. The method of claim 12, The sum of the widths of the concave portions is larger than the sum of the widths of the insulating films on which the concave portions are not formed in the light emitting region. The method of claim 20, And a ratio of the sum of the widths of the recesses and the sum of the widths of the insulating films on which the recesses are not formed in the light emitting region is 3: 1 to 5: 1.

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