Sony Patent | Display device and manufacturing method of display device, and electronic device

Patent: Display device and manufacturing method of display device, and electronic device

Drawings: Click to check drawins

Publication Number: 20210057499

Publication Date: 20210225

Applicant: Sony

Abstract

A display device of the present disclosure includes a plurality of recess portions provided on a pixel formation surface, and a pixel arranged in each of the plurality of recess portions, in which a light-emitting unit of the pixel is formed on a side wall and a bottom surface of each of the plurality of recess portions. A manufacturing method of a display device of the present disclosure is a manufacturing method of a display device having the above-described configuration. Furthermore, an electronic device of the present disclosure is an electronic device including a display device having the above-described configuration.

Claims

1. A display device comprising: a plurality of recess portions provided on a pixel formation surface; and a pixel arranged in each of the plurality of recess portions, wherein a light-emitting unit of the pixel is formed on a side wall and a bottom surface of each of the plurality of recess portions.

2. The display device according to claim 1, wherein the pixel includes a plurality of light-emitting units with light emission colors different from each other, and one of the plurality of light-emitting units is formed on a bottom surface of each of the plurality of recess portions.

3. The display device according to claim 2, wherein light emission colors of the plurality of light-emitting units include four colors of red, green, blue, and white, red, green, and blue light-emitting units are formed on side walls of each of the plurality of recess portions, and a white light-emitting unit is formed on the bottom surface of each of the plurality of recess portions.

4. The display device according to claim 3, wherein a light emission layer of a light-emitting unit formed on a side wall of a recess portion is formed by oblique evaporation of light emission material with respect to the side wall of the recess portion.

5. The display device according to claim 4, wherein, in oblique evaporation, an incident angle of light emission material with respect to the bottom surface of the recess portion is set to an angle at which the light emission layer is formed on the side wall and the bottom surface of the recess portion.

6. The display device according to claim 5, wherein the incident angle of the light emission material is set on a basis of a size of a side anode electrode formed on the side wall of the recess portion, and a size of a bottom anode electrode formed on the bottom surface of the recess portion.

7. The display device according to claim 2, wherein light emission colors of the plurality of light-emitting units include two colors of red, green, and blue, light-emitting units of two colors among three colors are formed on side walls of each of the plurality of recess portions, and a light-emitting unit of a remaining one color is formed on the bottom surface of each of the plurality of recess portions.

8. The display device according to claim 7, wherein a light emission layer of a light-emitting unit formed on a side wall of a recess portion is formed by oblique evaporation of light emission material with respect to the side wall of the recess portion.

9. The display device according to claim 8, wherein, in oblique evaporation, an incident angle of light emission material with respect to the bottom surface of the recess portion is set to an angle at which the light emission layer is not formed on the bottom surface of the recess portion.

10. The display device according to claim 1, wherein the light-emitting unit of the pixel includes as organic electroluminescent element.

11. A manufacturing method of a display device including a plurality of recess portions provided on a pixel formation surface, and a pixel arranged in each of the plurality of recess portions, the manufacturing method comprising: in manufacturing the display device, forming a light-emitting unit of the pixel on a side wall and a bottom surface of each of the plurality of recess portions.

12. The manufacturing method of a display device according to claim 11, wherein the pixel includes a plurality of light-emitting units with light emission colors different from each other, and one of the plurality of light-emitting units is formed on a bottom surface of each of the plurality of recess portions.

13. The manufacturing method of a display device according to claim 12, wherein light emission colors of the plurality of light-emitting units include four colors of red, green, blue, and white, red, green, and blue light-emitting units are formed on side walls of each of the plurality of recess portions, and a white light-emitting unit is formed on the bottom surface of each of the plurality of recess portions.

14. The manufacturing method of a display device according to claim 13, wherein a light emission layer of a light-emitting unit formed on a side wall of a recess portion is formed by oblique evaporation of light emission material with respect to the side wall of the recess portion.

15. The manufacturing method of a display device according to claim 14, wherein, in for a light emission layer on the side wall of the recess portion, oblique evaporation is performed at an incident angle of light emission material at which a light emission layer is formed on the bottom surface of the recess portion.

16. An electronic device comprising: a display device including a plurality of recess portions provided on a pixel formation surface, and a pixel arranged in each of the plurality of recess portions, wherein a light-emitting unit of the pixel is formed on a side wall and a bottom surface of each of the plurality of recess portions.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a display device and a manufacturing method of a display device, and an electronic device.

BACKGROUND ART

[0002] As a recent display device, a flat-panel type display device has prevailed. As one of flat-panel type display devices, there is a display device that uses, as a light-emitting unit (light-emitting element) of a pixel, a so-called current drive-type electrooptic element of which light emission luminance changes in accordance with a value of current flowing in the device. As the current drive-type electrooptic element, an organic EL element that uses electro luminescence (EL) of organic material and uses a phenomenon in which light is emitted by applying an electric field to an organic thin film has been known.

[0003] An organic EL element is formed by performing evaporation film formation using organic EL material on an anode electrode. Furthermore, as one of methods of implementing color display, there is a color coding method of individually patterning elements of respective colors of red (R), green (G), and blue (B). In the case of this color coding method, it is necessary to mask an electrode opening portion of another color for each color of RGB and evaporate organic EL material. Thus, the positioning accuracy of the mask restricts a pixel pitch. From the aspect of the accuracy of the mask, it is difficult to achieve higher definition and this tendency becomes prominent as the pixel pitch becomes smaller.

[0004] Meanwhile, in the conventional pixel array, elements of the respective colors of RGB are generally formed on a flat surface parallel to a substrate surface of a backplane substrate. In contrast to this, there has been proposed a light emission device in which a plurality of polyhedral structures is formed on a substrate, a light-emitting element is formed on an inclined surface of the polyhedral structure, and pixels are arrayed in stripe (for example, refer to Patent Document 1).

CITATION LIST

Patent Document

[0005] Patent Document 1: Japanese Patent Application. Laid-Open No. 2012-129041

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

[0006] In the prior art described in Patent Document 1 described above, the polyhedral structure having an inclined surface on which a light-emitting element is formed is a protruding portion formed in a state of protruding on the substrate. In the case of the prior art in which a light-emitting element is formed on an inclined surface of the polyhedral structure being a protruding portion on the substrate, light is emitted from a light-emitting element of each color in a direction getting away from the center of the pixel, that is to say, in a diffusing direction. Thus, a decline in light takeout efficiency and view angle dependency occur.

[0007] The present disclosure aims to provide a display device that enables higher definition using a color coding method, and can enhance light takeout efficiency, and a manufacturing method of the display device, and an electronic device including the display device.

Solutions to Problems

[0008] A display device of the present disclosure for achieving the above-described purpose includes a plurality of recess portions provided on a pixel formation surface, and a pixel arranged in each of the plurality of recess portions, in which a light-emitting unit of the pixel is formed on a side wall and a bottom surface of each of the plurality of recess portions.

[0009] Furthermore, a manufacturing method of a display device for achieving the above-described purpose includes, in manufacturing the display device including a plurality of recess portions provided on a pixel formation surface, and a pixel arranged in each of the plurality of recess portions, forming a light-emitting unit of the pixel on a side wall and a bottom surface of each of the plurality of recess portions.

[0010] Furthermore, an electronic device of the present disclosure for achieving the above-described purpose includes a display device having the above-described configuration.

BRIEF DESCRIPTION OF DRAWINGS

[0011] FIG. 1 is a system configuration diagram schematically illustrating a configuration of an organic EL display device to which the technology of the present disclosure is applied.

[0012] FIG. 2 is a circuit diagram illustrating an example of a circuit configuration of a pixel (pixel circuit) in the organic EL display device to which the technology of the present disclosure is applied.

[0013] FIG. 3A is a plan view illustrating a pixel structure according to the first embodiment, and FIG. 3B is a cross-sectional view illustrating a cross-sectional structure taken along an A-A line in FIG. 3A.

[0014] FIG. 4A is a schematic diagram illustrating a state of light emission of a subpixel of G, and FIG. 4B is a schematic diagram illustrating a state of light emission of a subpixel of W.

[0015] FIG. 5 is an explanatory diagram illustrating the setting of an incident critical angle of oblique evaporation.

[0016] FIG. 6 is a plan view illustrating a pixel structure according to a second embodiment.

[0017] FIG. 7 is a process diagram (1) illustrating a flow of a process of a manufacturing method of a pixel structure according to a third embodiment.

[0018] FIG. 8 is a process diagram (2) illustrating a flow of a process of a manufacturing method of a pixel structure according to a third embodiment.

[0019] FIG. 9 is a process diagram (3) illustrating a flow of a process of a manufacturing method of a pixel structure according to a third embodiment.

[0020] FIG. 10 is a process diagram (4) illustrating a flow of a process of a manufacturing method of a pixel structure according to a third embodiment.

[0021] FIG. 11 is a process diagram (5) illustrating a flow of a process of a manufacturing method of a pixel structure according to a third embodiment.

[0022] FIG. 12A is a plan view illustrating a pixel structure according to the fourth embodiment, and FIG. 12B is a cut portion end surface diagram taken along a B-B line in FIG. 12A.

[0023] FIG. 13 is a schematic diagram illustrating a state of light emission of subpixel of B.

[0024] FIG. 14 is a plan view illustrating a pixel structure according to a fifth embodiment, and FIGS. 14A, 14B, and 14C illustrate another example of a shape of a side anode electrode.

[0025] FIG. 15 is a process diagram (1) illustrating a flow of a process of a manufacturing method of a pixel structure according to a sixth embodiment.

[0026] FIG. 16 is a process diagram (2) illustrating a flow of a process of a manufacturing method of a pixel structure according to the sixth embodiment.

[0027] FIG. 17A is a front view of a digital still camera of a lens-interchangeable single-lens reflex type according to Specific Example 1 of an electronic device of the present disclosure, and FIG. 17B is a rear view of the digital still camera.

[0028] FIG. 18 is an external view illustrating an example of a head-mounted display according to Specific Example 2 of an electronic device of the present disclosure.

MODE FOR CARRYING OUT THE INVENTION

[0029] Hereinafter, a mode for carrying out the technology of the present disclosure (hereinafter, will be described as an “embodiment”) will be described using the drawings. The technology of the present disclosure is not limited to an embodiment, and various numerical values, materials, and the like in the embodiment are exemplifications. In the following description, the same components or components having the same function are assigned the same reference numerals, and the redundant description will be omitted. Note that the description will be given in the following order.

1. Display Device of Present Disclosure and Manufacturing Method of The Same, and Electronic Device, and Overall Description

2. Display Device to Which Technology of Present Disclosure Is Applied

[0030] 2-1. System Configuration

[0031] 2-2. Pixel Circuit

[0032] 2-3. Color Coding Method

3. Embodiment of Present Disclosure

[0033] 3-1. First Embodiment (Example in Which Pixel includes Subpixels of Four Colors of RGBW)

[0034] 3-2. Second Embodiment (Modified Example of First Embodiment: Another Example of Shape of Recess Portion)

[0035] 3-3. Third Embodiment (Example of Manufacturing Method of Pixel Structure According to First Embodiment)

[0036] 3-4. Fourth Embodiment (Example in which Pixel Includes Subpixels of Three Colors of RGB)

[0037] 3-5. Fifth Embodiment (Modified Example of Fourth Embodiment: Another Example of Shape of Side Anode Electrode)

[0038] 3-6. Sixth Embodiment (Example of Manufacturing Method of Pixel Structure According to Fourth Embodiment)

4. Modified Example

5. Electronic Device of Present Disclosure

[0039] 5-1. Specific Example 1 (Example of Digital Still Camera)

[0040] 5-2. Specific Example 2 (Example of Head-Mounted Display)

6. Configuration That Can Be Employed in Present Disclosure

Display Device of Present Disclosure and Manufacturing Method of The Same, and Electronic Device, and Overall Description

[0041] In the display device of the present disclosure and a manufacturing method of the same, and an electronic device, a pixel has a configuration including a plurality of light-emitting units with light emission colors different from each other. Then, one of the plurality of light-emitting units is formed on the bottom surface of each of a plurality of recess portions.

[0042] In the display device of the present disclosure and a manufacturing method of the same, and the electronic device that include the above-described preferable configuration, light emission colors of a plurality of light-emitting units include four colors of red, green, blue, and white, red, green, and blue light-emitting units are formed on side walls of each of a plurality of recess portions, and a white light-emitting unit is formed on the bottom surface of each of the plurality of recess portions.

[0043] Moreover, in the display device of the present disclosure and a manufacturing method of the same, and the electronic device that include the above-described preferable configuration, a light emission layer of a light-emitting unit formed on the side wall of the recess portion can be formed by oblique evaporation of light emission material with respect to the side wall of the recess portion. Then, in the oblique evaporation, an incident angle of light emission material with respect to the bottom surface of the recess portion is preferably set to an angle at which the light emission layer is formed on the side wall and the bottom surface of the recess portion. Furthermore, an incident angle of the light emission material can be set on the basis of a size of the side anode electrode formed on the side wall of the recess portion, and a size of a bottom anode electrode formed on the bottom surface of the recess portion.

[0044] Alternatively, in the display device of the present disclosure and a manufacturing method of the same, and the electronic device that include the above-described preferable configuration, light emission colors of a plurality of light-emitting units include two colors of red, green, and blue, light-emitting units of two colors among three colors are formed on side walls of each of a plurality of recess portions, and a light-emitting unit of a remaining one color is formed on the bottom surface of each of the plurality of recess portions.

[0045] Moreover, in the display device of the present disclosure and a manufacturing method of the same, and the electronic device that include the above-described preferable configuration, a light emission layer of a light-emitting unit formed on the side wall of the recess portion can be formed by oblique evaporation of light emission material with respect to the side wall of the recess portion. Then, in the oblique evaporation, an incident angle of light emission material with respect to the bottom surface of the recess portion is preferably set to an angle at which the light emission layer is not formed on the bottom surface of the recess portion.

[0046] Moreover, in the display device of the present disclosure and a manufacturing method of the same, and the electronic device that include the above-described preferable configuration, a light-emitting unit of a pixel can have a configuration of including an organic electroluminescence element.

Display Device to which Technology of Present Disclosure is Applied

[0047] A display device to which the technology of the present disclosure is applied is an active matrix type display device that controls current flowing in an electrooptic element, using an active element provided in the same pixel circuit as the electrooptic element, such as an insulated gate field effect transistor, for example. As an insulated gate field effect transistor, typically, a metal oxide semiconductor (MOS) transistor and a thin film transistor (TIT) can be exemplified.

[0048] Here, as an example, the description will be given using an example of an active matrix type organic EL display device that uses a current drive type electrooptic element such as an organic EL element, for example, that changes in light emission luminance in accordance with a value of current flowing in a device, as a light-emitting unit (light emitting element) of a pixel circuit.

System Configuration

[0049] FIG. 1 is a system configuration diagram schematically illustrating a configuration of an organic EL display device to which the technology of the present disclosure is applied. As illustrated in FIG. 1, an organic EL display device 10 according to this application example has a configuration including a pixel allay portion 30 including a plurality of pixels 20 including an organic EL element that is two-dimensionally arrayed in a matrix shape, and a peripheral circuit portion that drives each pixel 20 of the pixel allay portion 30.

[0050] The organic EL display device 10 according to this application example is a display device that supports color display. Then, the pixel 20 is a main pixel serving as a unit for forming a color image, and each includes a plurality of subpixels having light emission colors different from each other. As an example, the pixel 20 includes four subpixels including a subpixel 20r that emits red (R) light, a subpixel 20g that emits green (G) light, a subpixel 20b that emits blue (13) light, and a subpixel 20w that emits white (W) light.

[0051] The subpixels 20r, 20g, 20b, and 20w are arranged in a grid, for example. In the grid arrangement, the array of the subpixels 20r, 20g, 20b, and 20w is not limited to a color array illustrated in FIG. 1. Hereinafter, the subpixels 20r, 20g, 20b, and 20w will be sometimes collectively referred to as a subpixel 20s.

[0052] The peripheral circuit portion includes, for example, a writing scanning unit 40 mounted on the same display panel 70 as the pixel allay portion 30, a drive scanning unit. 50, a signal output unit 60, and the like, and drives each of the subpixels 20s of the pixel allay portion 30. Note that a configuration in which a part or all of the writing scanning unit 40, the drive scanning unit 50, and the signal output unit 60 are provided on the outside of the display panel 70 can be employed.

[0053] As a substrate of the display panel 70, an insulative transparent substrate such as a glass substrate can be used, or a semiconductor substrate such as a silicon substrate can also be used. An organic EL display device that uses a semiconductor substrate such as a silicon substrate, as a substrate of the display panel 70 is referred to as a so-called micro display (compact display), and is preferably used as an electronic viewfinder of a digital still camera, a display unit of a head-mounted display, or the like.

[0054] In the pixel allay portion 30, for an array of the subpixel 20s in m rows and n columns, scanning lines 31 (31.sub.1 to 31.sub.m) and drive lines 32 (32.sub.1 to 32.sub.m) are laid for each pixel row along a row direction (array direction of pixels in a pixel row/horizontal direction). Moreover, for the array of subpixels 20s in m rows and n columns, signal lines 33 (33.sub.1 to 33.sub.n) are laid for each pixel column along a column direction (array direction of pixels in a pixel column/vertical direction).

[0055] The scanning line 31.sub.1 to 31.sub.m are respectively connected to output ends of corresponding rows of the writing scanning unit 40. The drive line 32.sub.1 to 32.sub.m are respectively connected to output ends of corresponding rows of a drive scanning unit 50. The signal line 33.sub.1 to 33.sub.n are respectively connected to output ends of corresponding columns of the signal output unit 60.

[0056] The writing scanning unit 40 includes a shift register circuit, an address decoder, and the like. The writing scanning unit 40 performs so-called linear sequential scanning of sequentially scanning the subpixels 20s of the pixel allay portion 30 for each row by sequentially supplying writing scanning signals WS (WS.sub.1 to WS.sub.m) to the scanning lines 31 (31.sub.1 to 31.sub.m) in writing a signal voltage of a video signal into each of the subpixels 20s of the pixel allay portion 30.

[0057] Similarly to the writing scanning unit 40, the drive scanning unit 50 includes a shift register circuit, an address decoder, and the like. The drive scanning unit 50 performs control of light emission/light non-emission (extinction) of the subpixels 20s by supplying light emission control signals DS (DS.sub.1 to DS.sub.m) to the drive lines 32 (32.sub.1 to 32.sub.m) in synchronization with linear sequential scanning performed by the writing scanning unit 40.

[0058] The signal output unit 60 selectively outputs a signal voltage of a video signal (hereinafter, will be sometimes simply described as a “signal voltage”) V.sub.sig that corresponds to luminance information supplied from a signal supply source (not illustrated), and a reference voltage V.sub.ofs. Here, the reference voltage V.sub.ofs is a voltage corresponding to a voltage on which the signal voltage V.sub.sig of the video signal is based. (for example, voltage corresponding to a black level of the video signal), or a voltage in the vicinity thereof. The reference voltage V.sub.ofs is used as an initialization voltage in performing a correction operation.

[0059] The signal voltage V.sub.sig/reference voltage V.sub.ofs selectively output from the signal output unit 60 is written into the subpixels 20s of the pixel allay portion 30 via the signal lines 34 (34.sub.1 to 34.sub.n) for each pixel row selected by linear sequential scanning performed by the writing scanning unit 40. In other words, the signal output unit 60 employs a drive configuration of linear sequential writing of writing the signal voltage V.sub.sig for each pixel row (line).

Pixel Circuit

[0060] FIG. 2 is a circuit diagram illustrating an example of a circuit configuration of a pixel (pixel circuit) in the organic EL display device 10 to which the technology of the present disclosure is applied. A light-emitting unit of the subpixel 20s includes an organic EL element 21. The organic EL element 21 is an example of a current drive type electrooptic element having light emission luminance changing in accordance with a value of current flowing in the device.

[0061] As illustrated in FIG. 2, the subpixel 20s includes the organic EL element 21, and a drive circuit (pixel drive circuit) that drives the organic EL element 21 by flowing current in the organic EL element 21. A cathode electrode of the organic EL element 21 is connected to a common power source line 34 laid in common to all the subpixels 20s. In the drawing, C.sub.el denotes equivalent capacitance of the organic EL element 21.

[0062] A drive circuit unit that drives the organic EL element 21 has a configuration including a drive transistor 22, a sampling transistor 23, a light emission control transistor 24, a holding capacitance 25, and an auxiliary capacitance 26. Here, it is assumed that the organic EL element 21 and the drive circuit thereof are not formed on an insulating material such as a glass substrate but on a semiconductor substrate such as a silicon substrate, and the drive transistor 22 employs a configuration of using a P-channel type transistor.

[0063] Furthermore, in this example, the sampling transistor 23 and the light emission control transistor 24 also employ a configuration of using a P-channel type transistor similarly to the drive transistor 22. Accordingly, the drive transistor the sampling transistor 23, and the light emission control transistor 24 have a four-terminal configuration including source/gate/drain/back gate instead of a three-terminal configuration including source/gate/drain. A source voltage V.sub.dd is applied to a back gate.

[0064] Nevertheless, because the sampling transistor 23 and the light emission control transistor 24 are switching transistors functioning as switch elements, the sampling transistor 23 and the light emission control transistor 24 are not limited to P-channel type transistors. Accordingly, the sampling transistor 23 and the light emission control transistor 24 may be N-channel type transistors or may have a configuration in which P-channel type transistors and N-channel type transistors mixedly exist.

[0065] In the subpixel 20s having the above-described configuration, the sampling transistor 23 performs writing into the holding capacitance 25 by sampling the signal voltage V.sub.sig of the video signal supplied from the signal output unit 60 through the signal line 33. The light emission control transistor 24 is connected between a node of the source voltage V.sub.dd and a source electrode of the drive transistor 22, and controls light emission/light non-emission of the organic EL element 21 under the driving performed in accordance with the light emission control signal DS.

[0066] The holding capacitance 25 is connected between a gate electrode and a source electrode of the drive transistor 22. The holding capacitance 25 holds the signal voltage V.sub.sig of the video signal written into by the sampling performed by the sampling transistor 23. The drive transistor 22 drives the organic EL element 21 by flowing drive current corresponding a voltage held by the holding capacitance 25, in the organic EL element 21.

[0067] The auxiliary capacitance 26 is connected between the source electrode of the drive transistor 22 and a node with a fixed potential such as, for example, the node of the source voltage V.sub.dd. The auxiliary capacitance 26 has a function of suppressing a variation in source potential of the drive transistor 22 when the signal voltage V.sub.sig of the video signal is written into, and has a function of setting a gate-source voltage V.sub.gs of the drive transistor 22 to a threshold voltage V.sub.th of the drive transistor 22.

Color Coding Method

[0068] In the organic EL display device 10 having the above-described configuration, the organic EL element 21 is formed by performing evaporation film formation using organic EL material being light emission material on an anode electrode using a color coding method, which is one of coloring methods. Because the color coding method coats the subpixels 20s (20r, 20g, 20b, and 20w) with different colors, and causes the organic EL element 21 of each color to emit light, the color coding method has a larger advantages from the aspect of light emission efficiency and light takeout efficiency as compared with a method of using a color filter.

[0069] Nevertheless, in the case of the color coding method, because it is necessary to mask an electrode opening portion of another color for each color of the subpixels 20s, and evaporate organic EL material, the positioning accuracy of the mask restricts a pixel pitch. Thus, from the aspect of the accuracy of the mask, it is difficult to achieve higher definition and this tendency becomes prominent as the pixel pitch becomes smaller.

Embodiment of Present Disclosure

[0070] In view of the foregoing, in an embodiment of the present disclosure, for enabling higher definition using the color coding method, a so-called stereoscopic arrangement structure of the pixel 20 in which a plurality of recess portions is provided on a pixel formation surface, and the pixel 20 is arranged in each of the plurality of recess portions is employed. At this time, the organic EL element 21 being a light-emitting unit of the pixel 20 is formed for each of the subpixels 20s (20r, 20g, 20b, 20w) using the side wall and the bottom surface (bottom portion) of each of the plurality of recess portions. Here, the light emission colors of the organic EL element 21 are four colors of RGBW, but the light emission colors are not limited to these. For example, the light emission colors may be three colors of RGB, or all colors can be set to white for the purpose of achieving higher luminance.

[0071] Hereinafter, a specific embodiment of the present embodiment for enabling higher definition using the color coding method will be described.

First Embodiment

[0072] The first embodiment is an example in which the pixel 20 includes the subpixels 20r, 20g, 20b, and 20w of four colors of RGBW. FIG. 3A illustrates a plan view of a pixel structure according to the first embodiment, and FIG. 3B illustrates a cross-sectional view taken along an A-A line in FIG. 3A. Here, it is assumed that the organic EL element 21 and the drive circuit thereof are formed on a semiconductor substrate such as a silicon substrate.

[0073] Generally, a circuit layer on which the drive circuit is formed is stacked on the semiconductor substrate, an interlayer insulating film 81 illustrated in FIG. 3B is formed on the circuit layer, and the pixel 20 is formed on the interlayer insulating film 81. In other words, the top surface of the interlayer insulating film 81 becomes a pixel formation surface, and the pixel 20 is formed on the pixel formation surface.

[0074] The pixel structure according to the first embodiment has a configuration in which a plurality of recess portions 82 corresponding to the number of pixels 20 is provided on the top surface of the interlayer insulating film 81, which is a pixel formation surface, and the pixel 20 including the subpixels 20r, 20g, 20b, and 20w of four colors of RGBW is arranged in each of the plurality of recess portions 82. In other words, the pixel structure according to the first embodiment has a stereoscopic arrangement structure in which the pixel 20 including the subpixels 20r, 20g, 20b, and 20w of four colors of RGBW is arranged in each of the plurality of recess portions 82.

[0075] In a planar view, the plurality of recess portions 82 has a substantially circular shape, for example, and has a configuration divided into three in a circumferential direction. In the present embodiment, the side wall (side surface) of the recess portion 82 is a vertical surface vertical to the pixel formation surface. Here, the “vertical surface” includes a case of a substantially vertical surface in addition to a case of a strictly vertical surface, and the existence of various variations generated in design or manufacturing is allowed. Nevertheless, the side wall needs not be always a vertical surface, and may be an inclined surface inclining in a direction in which an opening of the recess portion 82 widens.

[0076] In the pixel structure according to the first embodiment, the use of the side wall and the bottom surface (bottom portion) of the recess portion 82 enables the pixel 20 including the subpixels 20r, 20g, 20b, and 20w of RGBW to be arranged in one recess portion 82. Specifically, the respective organic EL elements 21 of the subpixels 20r, 20g, and 20b of RGB are formed on the three-divided side walls of the recess portion 82, and the organic EL element 21 of the subpixel 20w of W is formed on the bottom surface of the recess portion 62.

[0077] FIG. 3B illustrates cross-sectional structures of the subpixel 20g of G, the subpixel 20r of R, and the subpixel 20w of W. Respective anode electrodes 83g and 63r of the subpixels 20g and 20r are buried in the side wall of the recess portion 82 as side anode electrodes, and an anode electrode 83w of the subpixel 20w is buried in the bottom surface of the recess portion 82 as a bottom anode electrode. As material of an anode electrode, for example, metal material such as aluminum (Al) or a stacked layer of indium tin oxide (ITO) and silver (Ag) can be used.

[0078] Then, in the pixel structure according to the first embodiment, a film is formed using organic EL material being light emission material on a side anode electrode by oblique evaporation. Arrows illustrated in FIG. 3A respectively indicate film formation directions of RGB by oblique evaporation. In the case of the present embodiment, for example, film formation of each color is performed using organic EL material in the order of G, R, and B.

[0079] First of all, a film of an organic EL layer 84g of G is formed on an anode electrode 83g of G by oblique evaporation. Therefore, the subpixel 20g of G is formed. At, this time, in the oblique evaporation, by setting an incident angle of organic EL material being light emission material to an optimum angle, the film of the organic EL layer 84g of G can be formed also on the anode electrode 83w of W on the bottom surface of the recess portion 82. The details of the incident angle of the organic EL material will be described later.

[0080] Next, a film of an organic EL layer 84r of R is formed on an anode electrode 83r of R by oblique evaporation. Therefore, the subpixel 20r of R is formed. At this time, by the oblique evaporation, the film of the organic EL layer 84r of R is formed on the organic EL layer 84g of G formed on the bottom surface of the recess portion 82.

[0081] Lastly, a film of an organic EL layer 84b of B is formed on an anode electrode 83b of B by oblique evaporation. Therefore, the subpixel 20b of B is formed. At this time, by the oblique evaporation, the film of the organic EL layer 84b of 3 is formed on the organic EL layer 84r of R formed on the bottom surface of the recess portion 82.

[0082] Furthermore, by the above-described three-times oblique evaporation of GRB, on the anode electrode 83w of W on the bottom surface of the recess portion 82, the organic EL layer 84g of G, the organic EL layer 84r of R, and the organic EL layer 84b of B are stacked. As a result, on the bottom surface of the recess portion 82, the subpixel 20w of W including the stacked layer of the organic EL layer 84g of G, the organic EL layer 84r of R, and the organic EL layer 84b of B is formed.

[0083] Then, a cathode electrode 85 including a transparent electrode is formed on the organic EL layer 84g of G, the organic EL layer 84r of R, and the organic EL layer 84b of B as a common electrode among all the pixels 20. As a material of the cathode electrode 85, for example, a material such as ITO, indium zink oxide (IZO), or zinc oxide (ZnO) can be used. A protection film 86 is formed on the cathode electrode 85.

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