Method for producing display device, and display device

Abstract

A method for producing a microcavity-type display device (101) includes: a first step (S1) of forming a plurality of reflective electrodes (1) and a plurality of protective layers (2) on the plurality of reflective electrodes (1), respectively; and a second step (S2) of forming a plurality of transparent electrode parts (3) having different thicknesses. In the second step (S2), the plurality of transparent electrode parts (3) are respectively formed above the plurality of protective layers (2).

Description

Display device manufacturing method and display device

[0001] The present disclosure relates to a method for manufacturing a display device and the display device.

[0002] Patent Document 1 discloses an organic EL color display in which the transparent electrodes of the organic EL elements have different film thicknesses corresponding to the emitted colors. EL is an abbreviation for ElectroLuminescence.

[0003] Japanese Patent Publication No. 2003-142277

[0004] Patent Document 1 discloses an example of a method for manufacturing an organic EL color display, in which each transparent electrode has a different number of layers corresponding to the emitted color. However, applying this method may damage the surface of a component located under a transparent electrode with a smaller number of layers. This is because each time a transparent film is formed and a transparent electrode layer is patterned, the surface of the component is exposed to an etchant or the like.

[0005] Microcavity display devices have attracted attention as a way to realize display devices with high luminous efficiency. Microcavity display devices have a laminated structure of reflective electrodes and transparent electrodes, with each transparent electrode having a different thickness (optical path length) corresponding to the emitted color.

[0006] When manufacturing a microcavity display device, applying a method in which each transparent electrode section has a different number of layers corresponding to the luminescent color, the following problem occurs: The surface of the reflective electrode located under the transparent electrode section with a smaller number of layers may be damaged, causing an unintended change in the reflectivity of the reflective electrode, which may result in a decrease in the luminous efficiency of the display device.

[0007] A manufacturing method for a display device according to one embodiment of the present disclosure is a manufacturing method for a microcavity type display device, and includes a first step of forming a plurality of reflective electrodes and a plurality of protective layers respectively positioned on the plurality of reflective electrodes, and a second step of forming a plurality of transparent electrode portions having different thicknesses, wherein in the second step, the plurality of transparent electrode portions are each formed above the plurality of protective layers.

[0008] According to one aspect of the present disclosure, a microcavity display device with high luminous efficiency can be realized.

[0009] FIG. 1 is a cross-sectional view showing a schematic configuration of a display device according to a first embodiment of the present disclosure. FIG. 2 is an exploded view showing a schematic configuration of a display device according to the first embodiment of the present disclosure. FIG. 3 is a flowchart showing main steps in a manufacturing method of a display device according to the first embodiment of the present disclosure. FIG. 4 is a view illustrating step S11. FIG. 5 is a view illustrating step S12. FIG. 6 is a view illustrating steps S13 to S15. FIG. 7 is a view illustrating step S21. FIG. 8 is a view illustrating steps S22 to S24. FIG. 9 is a view illustrating step S25. FIG. 10 is a view illustrating steps S26 to S28. FIG. 11 is a view illustrating step S29. FIG. 12 is a view illustrating steps S2a to S2c. FIG. 13 is a cross-sectional view showing a schematic configuration of a plurality of reflective electrodes, a plurality of protective layers, and a plurality of transparent electrode portions according to a second embodiment of the present disclosure. FIG. 14 is a cross-sectional view showing a schematic configuration of a plurality of reflective electrodes, a plurality of protective layers, and a plurality of transparent electrode portions according to a third embodiment of the present disclosure. FIG. 15 is a flowchart showing main steps in a manufacturing method of a display device according to a fourth embodiment of the present disclosure.

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes an embodiment of the present disclosure. For convenience of explanation, the same reference numerals are used to designate components having the same functions as those previously described, and the description thereof may not be repeated.

[0011] [Embodiment 1] Fig. 1 is a cross-sectional view showing a schematic configuration of a display device 101 according to embodiment 1 of the present disclosure. Fig. 2 is an exploded view showing a schematic configuration of the display device 101 according to embodiment 1 of the present disclosure. The display device 101 is a microcavity type display device. The display device 101 includes a TFT substrate 51, a plurality of reflective electrodes 1, a plurality of protective layers 2, a plurality of transparent electrode portions 3, a plurality of optical function portions 52, and a plurality of counter electrodes 53. TFT is an abbreviation for Thin Film Transistor.

[0012] The display device 101 includes a first sub-pixel 54, a second sub-pixel 55, and a third sub-pixel 56. Each of the first sub-pixel 54, the second sub-pixel 55, and the third sub-pixel 56 has a laminated structure of a reflective electrode 1, a protective layer 2, a transparent electrode portion 3, an optical function portion 52, and a counter electrode 53.

[0013] The TFT substrate 51 is a substrate having TFTs (not shown) electrically connected to a plurality of reflective electrodes 1 .

[0014] Each of the plurality of reflective electrodes 1 is an electrode that reflects light. Each of the plurality of reflective electrodes 1 may be either an anode or a cathode. An example of the material of each of the plurality of reflective electrodes 1 is silver.

[0015] The protective layers 2 are respectively located on the reflective electrodes 1. In other words, one protective layer 2 is located on each reflective electrode 1.

[0016] The thicknesses of the multiple transparent electrode portions 3 are different from one another. The transparent electrode portion 3 of the first subpixel 54 is made up of a first transparent electrode layer 4, a second transparent electrode layer 5, and a third transparent electrode layer 6. The transparent electrode portion 3 of the second subpixel 55 is made up of the second transparent electrode layer 5 and the third transparent electrode layer 6. The transparent electrode portion 3 of the third subpixel 56 is made up of the third transparent electrode layer 6. As a result, the thickness of the transparent electrode portion 3 of the first subpixel 54 is greater than the thickness of the transparent electrode portion 3 of the second subpixel 55, and the thickness of the transparent electrode portion 3 of the second subpixel 55 is greater than the thickness of the transparent electrode portion 3 of the third subpixel 56.

[0017] The plurality of transparent electrode portions 3 are respectively located above the plurality of protective layers 2. In other words, for each protective layer 2, one transparent electrode portion 3 is located above it.

[0018] The optical function units 52 are each located above the transparent electrode units 3. Each of the optical function units 52 includes a light-emitting layer. Examples of the light-emitting layer include an OLED layer and a QLED layer. OLED is an abbreviation for Organic Light Emitting Diode. QLED is an abbreviation for Quantum Light Emitting Diode. Each of the optical function units 52 may include at least one of a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer.

[0019] The plurality of counter electrodes 53 are each located above the plurality of optical function units 52. Each of the plurality of counter electrodes 53 is a transparent or semi-transparent electrode. Each of the plurality of counter electrodes 53 may be the other of an anode and a cathode. An example of the material of each of the plurality of counter electrodes 53 is an alloy of silver and magnesium.

[0020] In each of the first sub-pixel 54 , the second sub-pixel 55 , and the third sub-pixel 56 , light can be emitted by the light-emitting layer of the optical function section 52 when a current flows between the reflective electrode 1 and the counter electrode 53 .

[0021] The multiple protective layers 2 include a first protective layer 7, a second protective layer 8, and a third protective layer 57. The first protective layer 7 is the protective layer 2 of the second sub-pixel 55, the second protective layer 8 is the protective layer 2 of the third sub-pixel 56, and the third protective layer 57 is the protective layer 2 of the first sub-pixel 54.

[0022] 3 is a flowchart showing main steps in a manufacturing method of the display device 101 according to the first embodiment of the present disclosure. The manufacturing method of the display device 101 includes a first step S1 and a second step S2. The first step S1 is a step of forming a plurality of reflective electrodes 1 and a plurality of protective layers 2 respectively positioned on the plurality of reflective electrodes 1. The second step S2 is a step of forming a plurality of transparent electrode portions 3 having different thicknesses. In the second step S2, the plurality of transparent electrode portions 3 are formed above the plurality of protective layers 2, respectively.

[0023] According to the manufacturing method of the display device 101, the protective layer 2 can reduce the risk of the surface of the reflective electrode 1 being exposed to an etchant or the like and being damaged, thereby reducing the risk of unintended changes in the reflectance of the reflective electrode 1. Therefore, according to the manufacturing method of the display device 101, it is possible to realize a microcavity type display device 101 with high luminous efficiency.

[0024] Fig. 4 is a diagram illustrating step S11. Fig. 5 is a diagram illustrating step S12. Fig. 6 is a diagram illustrating steps S13 to S15. The first process S1 may include steps S11 to S16.

[0025] Step S11 is a step of forming a reflective film 9. Step S12 is a step of forming a protective film 10 on the reflective film 9. The reflective film 9 and the protective film 10 are collectively patterned by photolithography in step S13, etching in step S14, and peeling and cleaning in step S15, thereby collectively forming a plurality of reflective electrodes 1 and a plurality of protective layers 2. Step S16 is a step of polycrystallizing the plurality of protective layers 2 by performing an annealing treatment on the plurality of protective layers 2.

[0026] Fig. 7 is a diagram illustrating step S21. Fig. 8 is a diagram illustrating steps S22 to S24. Fig. 9 is a diagram illustrating step S25. Fig. 10 is a diagram illustrating steps S26 to S28. Fig. 11 is a diagram illustrating step S29. Fig. 12 is a diagram illustrating steps S2a to S2c. The second process S2 may include steps S21 to S2c.

[0027] Step S21 is a process of forming a first transparent film 11 above the multiple protective layers 2. At least one first transparent electrode layer 4 included in the multiple transparent electrode portions 3 is formed by photolithography in step S22, etching in step S23, and peeling and cleaning in step S24. In steps S22 to S24, a portion of the first transparent film 11 located above the first protective layer 7 and a portion located above the second protective layer 8 are removed. A first etchant is used in the etching in step S23. Oxalic acid is an example of a material for the first etchant.

[0028] The etching rate of the first protective layer 7 with the first etchant and the etching rate of the second protective layer 8 with the first etchant may each be lower than the etching rate of the first transparent film 11 with the first etchant. This reduces the risk that the first protective layer 7 and the second protective layer 8 will be removed by etching in step S23. Therefore, the protection performance of the surface of the reflective electrode 1 located under the first protective layer 7 can be improved, and the protection performance of the surface of the reflective electrode 1 located under the second protective layer 8 can also be improved.

[0029] Step S25 is a process of forming a second transparent film 12 above at least one first transparent electrode layer 4, first protective layer 7, and second protective layer 8. At least two second transparent electrode layers 5 included in the plurality of transparent electrode portions 3 are formed by photolithography in step S26, etching in step S27, and peeling and cleaning in step S28. In steps S26 to S28, a portion of the second transparent film 12 located above the second protective layer 8 is removed. A second etchant is used in the etching in step S27. Oxalic acid is an example of a material for the second etchant.

[0030] The etching rate of the second protective layer 8 with the second etchant may be set lower than the etching rate of the second transparent film 12 with the second etchant. This reduces the risk that the second protective layer 8 will be removed by the etching in step S27, thereby improving the protection performance of the surface of the reflective electrode 1 located below the second protective layer 8.

[0031] Step S29 is a process of forming a third transparent film 13 above at least two second transparent electrode layers 5 and the second protective layer 8. At least three third transparent electrode layers 6 included in the plurality of transparent electrode portions 3 are formed by etching through photolithography in step S2a, etching in step S2b, and peeling and cleaning in step S2c.

[0032] The transparent electrode portions 3 may be made of an indium oxide-based amorphous material, and the protective layers 2 may be made of an indium oxide-based polycrystalline material. The first transparent film 11, the second transparent film 12, and the third transparent film 13 may each be made of an indium oxide-based amorphous material. Examples of indium oxide-based materials include ITO, IZO, and InGaZnO-based oxide semiconductors. ITO is an abbreviation for Indium Tin Oxide. IZO is an abbreviation for Indium Zinc Oxide. This makes it easy to set the etching rate of the protective layers 2 lower than that of the first transparent film 11 and lower than that of the second transparent film 12, thereby reducing the risk of the protective layers 2 being removed by etching.

[0033] 1 shows an example in which the first subpixel 54, which has the thickest transparent electrode portion 3, emits red light, the second subpixel 55, which has the next thickest transparent electrode portion 3 after the first subpixel 54, emits green light, and the third subpixel 56, which has the thinnest transparent electrode portion 3, emits blue light. This example shows that the following configuration may also be used. In the second step S2, for each of the plurality of transparent electrode portions 3, the longer the emission wavelength corresponding to that transparent electrode portion 3, the thicker the transparent electrode portion 3 is formed. In the display device 101, the longer the emission wavelength corresponding to that transparent electrode portion 3, the thicker the transparent electrode portion 3 is. As a result of these steps, it is possible to realize a display device 101 in which each transparent electrode portion 3 has a different thickness (optical path length) corresponding to the emission color, in other words, a display device 101 that is compatible with a microcavity type display device.

[0034] Referring to Figure 2, the display device 101 is formed by at least a reflective electrode 1 formed on a TFT substrate 51 in a BP (backplane) process, and a structure in which a light-emitting functional layer 52 and an opposing electrode 53 are stacked in this order above the reflective electrode 1 in an FP (frontplane) process.

[0035] The light-emitting layer of the light-emitting functional layer 52 is a layer that has the function of recombining holes supplied from the anode side and electrons supplied from the cathode side to emit light. To efficiently generate this reaction, in addition to the light-emitting layer, multiple layers that have the roles of carrier transport and carrier injection are usually stacked above and below it in the FP process.

[0036] A structure utilizing the microcavity effect is used to efficiently extract light emitted from the light-emitting layer of the light-emitting functional layer 52 and to enhance color purity. This structure optimizes the optical path length between the reflective electrode 1 and the counter electrode 53 according to the emission wavelength. The optical path length between the reflective electrode 1 and the counter electrode 53 can be controlled by the number of layers between the reflective electrode 1 and the counter electrode 53 and the thickness of each layer. For example, when adjusting in the FP process, the thickness of the hole transport layer can be varied for each emitted color. For example, when adjusting in the BP process, the transparent electrode unit 3 is formed on the reflective electrode 1, and the number of transparent electrode layers constituting the transparent electrode unit 3 and the thickness of each transparent electrode layer can be varied for each emitted color. The microcavity effect is caused by multiple reflections between the reflective electrode 1 and the counter electrode 53. In addition to the aforementioned optical path length control, the reflectivity of the reflective electrode 1 also plays a role in affecting its efficiency. Therefore, adjustment methods in the BP process, which involve processing on the reflective electrode 1, can be problematic due to a decrease in reflectivity caused by deterioration due to exposure of the reflective electrode 1.

[0037] This embodiment can be interpreted as proposing a structure in which a protective layer 2 is provided between a reflective electrode 1 and a transparent electrode portion 3 for adjusting the optical path length, as an improvement to the microcavity effect in the BP process. The display device 101 has a plurality of sub-pixels in which a reflective electrode 1, a protective layer 2, a transparent electrode portion 3, a light-emitting functional layer 52, and a counter electrode 53 are stacked in this order, and each of the plurality of sub-pixels is designed to have an optical path length corresponding to the emitted color.

[0038] In particular, if the protective layer 2 is not formed on the reflective electrode 1 of the third subpixel 56, it will be exposed twice to oxalic acid or the like during etching. However, if the protective layer 2 is formed, the surface of the reflective electrode 1 is protected, thereby reducing the risk of the reflectivity of the reflective electrode 1 changing unintentionally.

[0039] The thickness of the protective film 10 formed in step S12 may be 5 nm or more and 20 nm or less. In steps S13 to S15, the photoresist for forming the plurality of reflective electrodes 1 and the photoresist for forming the plurality of protective layers 2 may be shared.

[0040] Before the annealing treatment in step S16, the material of the plurality of protective layers 2 may be an indium oxide-based amorphous material, which makes it possible to easily perform the steps before step S15.

[0041] Since the plurality of reflective electrodes 1 and the plurality of protective layers 2 can be formed at the same time, it is not necessary to increase the number of photolithography steps and etching steps in association with the formation of the plurality of protective layers 2 .

[0042] The thickness of the first transparent electrode layer 4, the thickness of the second transparent electrode layer 5, and the thickness of the third transparent electrode layer 6 can each be adjusted according to the emission wavelength corresponding to the transparent electrode portion 3. For example, the thickness of the first transparent electrode layer 4 may be 60 nm, the thickness of the second transparent electrode layer 5 may be 30 nm, and the thickness of the third transparent electrode layer 6 may be 60 nm. In this case, the thickness of the transparent electrode portion 3 is 150 nm in the first sub-pixel 54, 90 nm in the second sub-pixel 55, and 60 nm in the third sub-pixel 56.

[0043] Second Embodiment FIG. 13 is a cross-sectional view showing a schematic configuration of a plurality of reflective electrodes 1, a plurality of protective layers 2, and a plurality of transparent electrode portions 3 according to a second embodiment of the present disclosure.

[0044] In the second step S2, the width W14 of the target transparent electrode portion 14, which is any one of the plurality of transparent electrode portions 3, may be formed to be smaller than the width W15 of the target reflective electrode 15 corresponding to the target transparent electrode portion 14 among the plurality of reflective electrodes 1. In addition, in the second step S2, the width W14 may be formed to be smaller than the width W16 of the target protective layer 16 corresponding to the target transparent electrode portion 14 among the plurality of protective layers 2.

[0045] The width W14 of the target transparent electrode portion 14, which is one of the plurality of transparent electrode portions 3, may be smaller than the width W15 of the target reflective electrode 15 corresponding to the target transparent electrode portion 14 among the plurality of reflective electrodes 1. In addition, the width W14 may be smaller than the width W16 of the target protective layer 16 corresponding to the target transparent electrode portion 14 among the plurality of protective layers 2.

[0046] Each of these allows the edge of the target protective layer 16 to be covered by the bank 58, thereby improving the coverage of the bank 58.

[0047] Third Embodiment FIG. 14 is a cross-sectional view showing a schematic configuration of a plurality of reflective electrodes 1, a plurality of protective layers 2, and a plurality of transparent electrode portions 3 according to a third embodiment of the present disclosure.

[0048] In the second step S2, the width W14 of the target transparent electrode portion 14, which is any one of the plurality of transparent electrode portions 3, may be formed to be larger than the width W15 of the target reflective electrode 15 corresponding to the target transparent electrode portion 14 among the plurality of reflective electrodes 1. In addition, the width W14 may be formed to be larger than the width W16 of the target protective layer 16 corresponding to the target transparent electrode portion 14 among the plurality of protective layers 2. In the second step S2, the side surface of the target reflective electrode 15 and the side surface of the target protective layer 16 may be covered by the target transparent electrode portion 14.

[0049] The width W14 of the target transparent electrode portion 14, which is any one of the plurality of transparent electrode portions 3, may be larger than the width W15 of the target reflective electrode 15 corresponding to the target transparent electrode portion 14 among the plurality of reflective electrodes 1. In addition, the width W14 may be larger than the width W16 of the target protective layer 16 corresponding to the target transparent electrode portion 14 among the plurality of protective layers 2. In the display device 101, the side surface of the target reflective electrode 15 and the side surface of the target protective layer 16 may be covered by the target transparent electrode portion 14.

[0050] As a result of these, the target transparent electrode portion 14 can protect the target reflective electrode 15 and the target protective layer 16, and damage to the target reflective electrode 15 and the target protective layer 16 caused by stagnation before the formation of the bank 58, etc. can be reduced.

[0051] In the display device 101 according to the third embodiment of the present disclosure, the distance between two adjacent subpixels can be determined by the transparent electrode portion 3 rather than the reflective electrode 1, which has a large side shift during wet etching, which is advantageous for achieving high definition.

[0052] Fourth Embodiment FIG. 15 is a flowchart showing main steps in a method for manufacturing a display device 101 according to a fourth embodiment of the present disclosure.

[0053] In the first step S1, the temperature of the material of the protective film 10 during deposition may be set to 150° C. or higher. This makes it possible to omit the annealing treatment in step S16. The "high temperature condition" in step S12 indicates that the temperature of the material of the protective film 10 during deposition is a high temperature of 150° C. or higher.

[0054] In the manufacturing method of the display device 101 according to the fourth embodiment of the present disclosure, a film obtained by crystal growth is used, so that the protective layer 2 can be formed thin, which is advantageous for reducing costs and realizing a tapered shape.

[0055] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

[0056] REFERENCE SIGNS LIST 1 Reflective electrode 2 Protective layer 3 Transparent electrode portion 4 First transparent electrode layer 5 Second transparent electrode layer 6 Third transparent electrode layer 7 First protective layer 8 Second protective layer 9 Reflective film 10 Protective film 11 First transparent film 12 Second transparent film 13 Third transparent film 14 Transparent electrode portion of interest 15 Reflective electrode of interest 16 Protective layer of interest 101 Display device

Claims

1. A method for manufacturing a microcavity type display device, comprising: a first step of forming a plurality of reflective electrodes and a plurality of protective layers respectively positioned on the plurality of reflective electrodes; and a second step of forming a plurality of transparent electrode portions having thicknesses different from one another, wherein in the second step, the plurality of transparent electrode portions are formed above the plurality of protective layers.

2. A method for manufacturing a display device as described in claim 1, wherein the plurality of protective layers include a first protective layer and a second protective layer, and in the second step, a first transparent film is formed above the plurality of protective layers, and a portion of the first transparent film located above the first protective layer and a portion located above the second protective layer are removed by etching using a first etchant, thereby forming at least one first transparent electrode layer included in the plurality of transparent electrode portions.

3. A method for manufacturing a display device as described in claim 2, wherein the etching rate of the first protective layer with the first etchant and the etching rate of the second protective layer with the first etchant are each lower than the etching rate of the first transparent film with the first etchant.

4. A method for manufacturing a display device as described in claim 2 or 3, wherein in the second step, a second transparent film is formed above the at least one first transparent electrode layer, the first protective layer, and the second protective layer, and a portion of the second transparent film located above the second protective layer is removed by etching using a second etchant, thereby forming at least two second transparent electrode layers included in the multiple transparent electrode portions.

5. The method for manufacturing a display device according to claim 4, wherein the etching rate of the second protective layer with the second etchant is set lower than the etching rate of the second transparent film with the second etchant.

6. A method for manufacturing a display device as described in claim 4 or 5, wherein in the second step, a third transparent film is formed above the at least two second transparent electrode layers and the second protective layer, and at least three third transparent electrode layers included in the plurality of transparent electrode portions are formed by etching.

7. A method for manufacturing a display device according to claim 3 or 5, wherein the material of the plurality of transparent electrode portions is an indium oxide-based amorphous material, and the material of the plurality of protective layers is an indium oxide-based polycrystalline material.

8. A method for manufacturing a display device according to any one of claims 1 to 7, wherein in the second step, for each of the plurality of transparent electrode portions, the longer the emission wavelength corresponding to the transparent electrode portion, the thicker the transparent electrode portion is formed.

9. A method for manufacturing a display device according to any one of claims 1 to 8, wherein in the first step, a reflective film is formed, a protective film is formed on the reflective film, and the reflective film and the protective film are patterned together to form the plurality of reflective electrodes and the plurality of protective layers together.

10. The method for manufacturing a display device according to claim 9, wherein in the first step, the temperature of the material of the protective film during deposition is set to 150° C. or higher.

11. A method for manufacturing a display device described in any one of claims 1 to 10, wherein in the second step, the width of a target transparent electrode portion, which is one of the plurality of transparent electrode portions, is formed to be smaller than the width of a target reflective electrode among the plurality of reflective electrodes that corresponds to the target transparent electrode portion, and smaller than the width of a target protective layer among the plurality of protective layers that corresponds to the target transparent electrode portion.

12. A method for manufacturing a display device described in any one of claims 1 to 10, wherein in the second step, the width of a target transparent electrode portion, which is one of the plurality of transparent electrode portions, is formed to be larger than the width of a target reflective electrode among the plurality of reflective electrodes that corresponds to the target transparent electrode portion, and larger than the width of a target protective layer among the plurality of protective layers that corresponds to the target transparent electrode portion.

13. The method for manufacturing a display device according to claim 12, wherein in the second step, the side surfaces of the target reflective electrode and the target protective layer are covered with the target transparent electrode portion.

14. A microcavity type display device comprising: a plurality of reflective electrodes; a plurality of protective layers respectively positioned on the plurality of reflective electrodes; and a plurality of transparent electrode portions having thicknesses different from one another, wherein the plurality of transparent electrode portions are each positioned above the plurality of protective layers.

15. The display device according to claim 14, wherein the material of the plurality of transparent electrode portions is an indium oxide-based amorphous material, and the material of the plurality of protective layers is an indium oxide-based polycrystalline material.

16. The display device according to claim 14 or 15, wherein, for each of the plurality of transparent electrode portions, the longer the emission wavelength corresponding to the transparent electrode portion, the thicker the transparent electrode portion is.

17. A display device according to any one of claims 14 to 16, wherein the width of a target transparent electrode portion, which is one of the plurality of transparent electrode portions, is smaller than the width of a target reflective electrode among the plurality of reflective electrodes that corresponds to the target transparent electrode portion, and is smaller than the width of a target protective layer among the plurality of protective layers that corresponds to the target transparent electrode portion.

18. A display device according to any one of claims 14 to 16, wherein the width of a target transparent electrode portion, which is one of the plurality of transparent electrode portions, is greater than the width of a target reflective electrode among the plurality of reflective electrodes that corresponds to the target transparent electrode portion, and is also greater than the width of a target protective layer among the plurality of protective layers that corresponds to the target transparent electrode portion.

19. The display device according to claim 18, wherein the target transparent electrode portion covers a side surface of the target reflective electrode and a side surface of the target protective layer.

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