Organic EL display device

Abstract

An organic EL display device, according to the present invention, comprising: a light-emitting element substrate in which light-emitting elements are formed at prescribed positions on a drive circuit board obtained by forming a drive circuit on a semiconductor substrate; and a color filter provided with at least red color pixels, green color pixels, and blue color pixels, at the positions corresponding to the light-emitting elements of the light-emitting element substrate in a plan view, wherein in a plan view, a light-shielding layer is formed at positions that do not overlap with the light-emitting elements and straddling the boundaries of the color pixels, and in a cross-sectional view, the surface of the light-shielding layer on the light-emitting elements side is the same as the surface of the color filter on the light-emitting elements side, or is disposed at the position of the color filter on the light-emitting elements side.

Description

[Technical Field]

[0001] The present invention relates to an organic EL display device, and more particularly to an organic EL display device with improved color reproducibility. This application claims priority from Japanese Patent Application No. 2020-191587, filed on November 18, 2020, the contents of which are incorporated by reference. [Background technology]

[0002] Known organic EL display devices include large organic EL display devices such as organic EL televisions, and small organic EL display devices used as head-mounted displays for virtual reality and the like, and display devices for smartphones.

[0003] Small organic EL display devices use a light-emitting element substrate manufactured by forming organic EL light-emitting elements on a drive circuit board, which has a drive circuit built into a semiconductor substrate such as a silicon wafer.

[0004] FIG. 2 shows an example of the cross-sectional structure of a conventional small organic EL display device (see, for example, Patent Document 1). An organic EL display device 20' uses a drive circuit board 12 in which a drive circuit is formed on a semiconductor substrate such as a silicon wafer. Light-emitting elements 11, each consisting of a red light-emitting element (red) 8, a green light-emitting element (green) 9, and a blue light-emitting element (blue) 10, are formed in portions of the drive circuit board 12 that correspond to the emitted light colors. Since the light-emitting elements deteriorate due to moisture and the like, a sealing layer 8 is formed to prevent deterioration, and a light-emitting element substrate 14 is obtained by sealing the light-emitting elements.

[0005] On the other hand, a color filter 13 is used to perform color correction of the light-emitting elements. To manufacture the color filter substrate 13, first a light-shielding layer 15' is formed on the glass substrate 1. This is generally called a black matrix, and areas where colored pixels are to be formed are formed within openings partitioned by the light-shielding layer 15'. The light-shielding layer 15' shields the boundary areas between adjacent colored pixels, thereby blocking unnecessary light and improving contrast.

[0006] Using this black matrix (light-shielding layer 15') as a reference pattern, color pixels (red) 2, color pixels (green) 3, and color pixels (blue) 4 are formed in this order to form a color filter 5, thereby obtaining a color filter substrate 13.

[0007] The light emitting element substrate 14 thus obtained and the color filter substrate 13 are bonded together via the resin layer 6' to obtain an organic EL display device 20'. The light emitting element (red) 8, light emitting element (green) 9, and light emitting element (blue) 10 of the light emitting element substrate 14 and the colored pixel (red) 2, colored pixel (green) 3, and colored pixel (blue) 4 of the color filter substrate 13 are bonded together with the same colors aligned. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 6019997 Summary of the Invention [Problem to be solved by the invention]

[0009] 2, in conventional organic EL display devices, the sealing layer 7, the resin layer 6', and the color filter 5 are interposed between the light emitting element 11 and the light-shielding layer 15' of the light emitting element substrate 14, so it is not possible to block oblique light emitted from the light emitting element 11. As a result, it is not possible to obtain an organic EL display device with high color reproducibility.

[0010] In view of the above circumstances, an object of the present invention is to provide an organic EL display device that has high color reproducibility by blocking oblique light emitted from a light emitting element. [Means for solving the problem]

[0011] A first aspect of the present invention is an organic EL display device comprising: a light-emitting element substrate on which light-emitting elements are formed at predetermined positions on a drive circuit substrate on which a drive circuit is formed on a semiconductor substrate; and a color filter having at least red, green, and blue colored pixels at positions corresponding to each light-emitting element on the light-emitting element substrate in a planar view. In this organic EL display device, when viewed in a plane, the light-shielding layer is formed across the boundaries of each colored pixel in a position where it does not overlap with the light-emitting element, and when viewed in a cross-section, the surface of the light-emitting element side of the light-shielding layer is positioned at the same position as the surface of the color filter facing the light-emitting element, or at a position on the light-emitting element side. The light-shielding layer has an upper portion whose upper surface is a convex curved surface, an intermediate portion provided below the upper portion and having a reverse tapered shape whose width gradually decreases downward, and a lower portion provided below the intermediate portion and having a forward tapered shape whose width gradually increases toward the light-emitting element. [Effects of the Invention]

[0013] According to the present invention, it is possible to effectively block oblique light emitted from a light emitting element, and to provide an organic EL display device with high color reproducibility. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a cross-sectional explanatory view illustrating an organic EL display device according to a first embodiment of the invention. [Figure 2] FIG. 1 is a cross-sectional view illustrating a conventional organic EL display device. [Figure 3] FIG. 4 is a cross-sectional view illustrating an organic EL display device according to a second embodiment of the invention. [Figure 4] FIG. 2 is a schematic cross-sectional view showing a light-shielding layer of the organic EL display device. [Figure 5] FIG. 10 is a schematic cross-sectional view showing a modified example of the organic EL display device. DETAILED DESCRIPTION OF THE INVENTION

[0015] An organic EL display device according to a first embodiment of the present invention will be described with reference to FIG.

[0016] The organic EL display device 20 of this embodiment is an organic EL display device comprising: a light emitting element substrate on which light emitting elements 11 are formed at predetermined positions on a drive circuit substrate 12 on which a drive circuit is formed on a semiconductor substrate; and a color filter 25 having at least a red colored pixel (colored pixel (red) 2), a green colored pixel (colored pixel (green) 3), and a blue colored pixel (colored pixel (blue) 4) at positions corresponding to each light emitting element (light emitting element (red) 8, light emitting element (green) 9, light emitting element (blue) 10) of the light emitting element substrate in a planar view.

[0017] In the organic EL display device 20 of the present invention, in a plan view, the light-shielding layer 15 is formed across the boundaries between adjacent colored pixels 2, 3, and 4, but at a position that does not overlap with the light-emitting elements 8, 9, and 10. In other words, the width of the light-shielding layer 15 is smaller than the width between adjacent light-emitting elements.

[0018] Furthermore, in a cross-sectional view, the surface of the light-shielding layer 15 facing the light-emitting element 11 is located at the same position as the surface of the color filter 25 facing the light-emitting element 11, or is disposed on the side of the light-emitting element 11. In other words, the thickness between the surface of the light-shielding layer 15 facing the light-emitting element 11 and the drive circuit board 12 is equal to or less than the thickness between the surface of the color filter 25 facing the light-emitting element 11 and the drive circuit board 12.

[0019] For example, when a sealing layer 7 is formed between the light-emitting element 11 and the color filter 25 to protect the light-emitting element 11 from moisture, etc., the light-shielding layer 15 can be formed on the surface of the sealing layer 7 on the color filter 25 side, or can be formed at a position where it is embedded in the thickness direction of the sealing layer 7.

[0020] With this configuration, light emitted from the light-emitting element 11 in a direction perpendicular to the plane of the light-emitting element 11 passes through the color filter 25 and is emitted from the glass substrate 1 without being blocked by the light-shielding layer 15. Furthermore, in the conventional configuration, the light-shielding layer 15' (see FIG. 2) was arranged on the glass substrate 1 side of the color filter 5 (at a position farther from the light-emitting element 11 by the thickness of the color filter 5), whereas in the configuration of the present invention, the light-shielding layer 15 is arranged on the light-emitting element 11 side of the color filter 25. Therefore, it becomes possible for the light-shielding layer 15 to block more of the light emitted obliquely from the light-emitting element 11 out of the light emitted from the light-emitting element (red) 8, light-emitting element (green) 9, and light-emitting element (blue) 10 of the light-emitting element 11. In other words, by blocking the oblique light that causes noise, color mixing between adjacent pixels is suppressed, and high color reproducibility can be maintained.

[0021] Furthermore, when the light-shielding layer 15 is formed at a position where it is embedded in the sealing layer 7 in the film thickness direction, it can be formed at a position closer to the light-emitting element 11 than when the light-shielding layer 15 is formed on the surface (on the color filter 25 side) of the sealing layer 7. Therefore, it is possible to block even more obliquely emitted light. For example, when the size of the light-shielding layer 15 as seen from a certain point on the light-emitting element (red) 8 of the light-emitting element 11 is compared between when the light-shielding layer 15 is far away and when the light-shielding layer 15 is close, the size of the light-shielding layer 15 appears larger in the latter case. Therefore, when the light-shielding layer 15 is formed at a position closer to the light-emitting element 11, it is possible to block even more obliquely emitted light.

[0022] As a method for forming the light-shielding layer 15 at a position where it is embedded in the film thickness direction of the sealing layer 7, for example, the sealing layer 7 is first formed as a layer thinner than the final thickness, and then the light-shielding layer 15 is formed in that state. After that, the sealing layer 7 can be further stacked so as to embed the light-shielding layer 15.

[0023] In this way, it is possible to block more of the oblique light emitted from the light emitting element 11, and therefore it is possible to provide an organic EL display device with high color reproducibility.

[0024] (glass substrate) The glass substrate 1 need not be particularly limited as long as it is made of a colorless, transparent glass material and is chemically stable. For example, alkali-free glass, available from several glass manufacturers, can be suitably used. Because alkali-free glass contains 0.1% or less alkali components, it has the advantage of negligibly reducing or virtually eliminating the adverse effects of alkali components on semiconductor elements. It also has a low thermal expansion coefficient and excellent dimensional stability. It is also chemically stable and does not corrode or deteriorate even when exposed to various chemicals during the manufacturing process. Furthermore, it is possible to select glass that does not contain heavy metals or other components that pollute the environment.

[0025] (Color filter) Conventional color pixels can be used for the color filter 25. In particular, photolithographic color pixels can be preferably used, which are produced by applying a photosensitive color resin composition onto a substrate, drying, exposing, and developing the composition.

[0026] (light-emitting element) The light-emitting element 11 includes at least a light-emitting element (red) 8 that is a red light-emitting element, a light-emitting element (green) 9 that is a green light-emitting element, and a light-emitting element (blue) 10 that is a blue light-emitting element, thereby enabling a display device capable of full-color display. In the organic EL display device 20 of the present invention, the light-emitting element (red) 8, the light-emitting element (green) 9 that is a green light-emitting element, and the light-emitting element (blue) 10 that is a blue light-emitting element are red-emitting OLEDs (Organic Light Emitting Diodes), green-emitting OLEDs, and blue-emitting OLEDs, respectively. OLEDs are also referred to as organic EL elements.

[0027] (Drive circuit board) The drive circuit board 12 is a substrate in which a drive circuit for the OLED and connection electrodes to the OLED are formed on a semiconductor substrate. Specifically, it is a substrate in which the drive circuit for the OLED is built into a silicon wafer. OLED drive circuits differ from LCD drive circuits. In LCD displays, each pixel can be considered a capacitor. Images are displayed using a voltage holding circuit that maintains the voltage of that capacitor at a certain value or higher during a frame period. On the other hand, OLED drive circuits display images using a current holding circuit that maintains a current at a predetermined value or higher during a frame period. While voltage holding circuits used in LCD displays use at least one transistor per pixel, current holding circuits used in OLED displays use at least two transistors per pixel.

[0028] (resin layer) The resin layer 6 is an adhesive layer or a pressure-sensitive adhesive layer that bonds the color filter 25 and the glass substrate 1 together. There are no particular limitations on the resin layer 6, as long as it is made of a transparent resin and functions as an adhesive layer or a pressure-sensitive adhesive layer.

[0029] Examples of adhesives include phenol resin, urea resin, melamine resin, solventless type, solvent type, and water-based type.

[0030] Solvent-free types include second-generation acrylic, epoxy, and hot melt, and hot melt types include EVA (ethylene vinyl acetate copolymer) and urethane.

[0031] Solvent-based types include vinyl acetate and synthetic rubber, which includes acrylic and chloroprene.

[0032] Examples of water-based types include vinyl acetate, EVA, and acrylic types. Among these adhesives, a material having excellent optical properties such as transparency can be selected and used.

[0033] Known adhesives include solvent-based, emulsion-based, hot-melt-based, and liquid-curing-based adhesives. As with adhesives, among these pressure sensitive adhesives, materials having excellent optical properties such as transparency can be selected and used.

[0034] (Sealing layer) The sealing layer 7 is formed to prevent the light emitting element 11 formed on the connection electrode for OLED formed at a predetermined position on the drive circuit board 12 from being deteriorated by moisture etc. This is because the organic semiconductor material constituting the OLED (organic EL element) which is the light emitting element 11 is deteriorated by moisture etc. in the atmosphere.

[0035] The material for the sealing layer 7 is not particularly limited as long as it is transparent and has a sealing function at a level that can prevent deterioration of the OLED, and inorganic materials, organic materials, and combinations thereof can be used.

[0036] As inorganic materials, silicon nitride (SiN X ), silicon oxide or metal oxide, etc.

[0037] The organic material may be made of a thermosetting resin or an ultraviolet curing resin.

[0038] (light shielding layer) The light-shielding layer 15 does not need to be particularly limited as long as it is made of a material that can form a matrix pattern or line pattern with an optical density (OD) of 0.8 or more, a thickness of 1.5 μm or less, a line width of 1.0 μm or less, and a pitch of 2.4 μm or less, and is capable of blocking light emitted from the light-emitting element 11.

[0039] For example, after forming a thin metal film of titanium, molybdenum, tantalum, or the like on the sealing layer 7, a photosensitive resist pattern can be formed and patterned by dry etching using a plasma etching device or a reactive ion etching device.

[0040] Alternatively, a black resist pattern can be formed by photolithography using a photosensitive black resist.

[0041] Examples of the first embodiment of the present invention will be described below. The technical concept of the present invention is not limited in any way by the specific content of the examples. Example 1 [OLED element manufacturing] A silicon substrate (drive circuit substrate) with a drive circuit built in was prepared in the pre-process of the wafer. After forming a white EL element on the silicon substrate using a known method such as vapor deposition, a silicon nitride sealing layer was coated using a CVD method to form an organic EL element substrate (light-emitting element substrate 14 in Figure 1).

[0042] Next, a colored composition was prepared in the following manner. [Preparation of Coloring Composition] (1) Black colored composition The colorants used in the colored compositions were as follows: Blue pigment: CI Pigment Blue 15:6 (LIONOL BLUE ES, manufactured by Toyocolor Co., Ltd.) Purple pigment: CI Pigment Violet 23 (LIONOGEN VIOLET RLj manufactured by Toyocolor Co., Ltd.) Yellow pigment: CI Pigment Yellow 139 (BASF PALIOTOL Yellow L 2146HDj) Each pigment was used to prepare a black colored resin composition.

[0043] ·Black colored materials A mixture of the following composition was stirred and mixed uniformly, dispersed in a sand mill using glass beads with a diameter of 1 mm for 5 hours, and then filtered through a 5 μm filter to prepare a dispersion of black pigment. Blue pigment: CI Pigment Blue 15:6 11 parts by weight Purple pigment: CI Pigment Violet 23 11 parts by weight Pigment for yellow: CIPigment Yellow 139 parts 6 parts by weight Acrylic varnish (solid content 20%) 170 parts by weight Thereafter, the mixture of the above composition was stirred and mixed to become uniform, and then filtered through a 5 μm filter to obtain a black colored material (BLK-1). Using this coloring material and other ingredients (resin, monomer, initiator, chain transfer agent, and solvent), a black photosensitive coloring composition (BLKR-1) was prepared according to the formulation shown in Table 1.

[0044] (2) Red colored composition The following colorants were used in the red colored composition. Red pigment: CI Pigment Red 254 (BASF Ilgarfor Red B-CF) Yellow pigment: CI Pigment Yellow 139 (Paliotrol Yellow L 2146HD manufactured by BASF) Using each pigment, a red colored resin composition was prepared.

[0045] ·Red colored material A mixture of the following composition was stirred and mixed uniformly, dispersed in a sand mill using glass beads with a diameter of 1 mm for 5 hours, and then filtered through a 5 μm filter to prepare a dispersion of red pigment. Red pigment: CI Pigment Red 254 78 parts by weight Yellow pigment: CI Pigment Yellow 139 22 parts by weight Acrylic varnish (solid content 20%) 215 parts by weight Thereafter, the mixture of the above composition was stirred and mixed to become uniform, and then filtered through a 5 μm filter to obtain a red colored material (R-1). Using this coloring material and other components (resin, monomer, initiator, chain transfer agent, and solvent), a red photosensitive coloring composition (RR-1) was prepared according to the formulation shown in Table 1.

[0046] (3) Green colored composition The following colorants were used in the red colored composition. Green pigment: CI Pigment Green 58 (DIC FASTOGEN GREEN A110) Yellow pigment: CI Pigment Yellow 185 (BASF Palitrol Yellow L1155) A green colored resin composition was prepared using each pigment.

[0047] ·Green coloring material A mixture of the following composition was stirred and mixed uniformly, dispersed in a sand mill using glass beads with a diameter of 1 mm for 5 hours, and then filtered through a 5 μm filter to prepare a dispersion of a green pigment. Green pigment: CI Pigment Green 58 65 parts by weight Yellow pigment: CI Pigment Yellow 185 35 parts by weight Acrylic varnish (solid content 20%) 215 parts by weight Thereafter, the mixture of the above composition was stirred and mixed to become uniform, and then filtered through a 5 μm filter to obtain a green colored material (G-1). Using this coloring material and other ingredients (resin, monomer, initiator, chain transfer agent, and solvent), a green photosensitive coloring composition (GR-1) was prepared according to the formulation shown in Table 1.

[0048] (4) Blue colored composition The following colorants were used in the blue colored composition. Blue pigment: CI Pigment Blue 15:6 (LIONOL BLUE ES, manufactured by Toyocolor Co., Ltd.) Purple pigment: CI Pigment Violet 23 (LIONOGEN VIOLET RLj manufactured by Toyocolor Co., Ltd.) Using each pigment, a blue colored resin composition was prepared.

[0049] ·Blue colored material A mixture of the following composition was stirred and mixed uniformly, then dispersed in a sand mill using glass beads with a diameter of 1 mm for 5 hours, and then filtered through a 5 μm filter to prepare a dispersion of a blue pigment. Blue pigment: CIPigment Blue 15:6 63 parts by weight Purple pigment: CI Pigment Violet 23 37 parts by weight Acrylic varnish (solid content 20%) 215 parts by weight Thereafter, the mixture of the above composition was stirred and mixed to become uniform, and then filtered through a 5 μm filter to obtain a blue colored material (B-1). Using this coloring material and other components (resin, monomer, initiator, chain transfer agent, and solvent), a blue photosensitive coloring composition (BR-1) was prepared according to the formulation shown in Table 1.

[0050] [Table 1]

[0051] [Fabrication of color filters and organic EL displays] A transparent resin composition for a planarizing film was applied to the sealing layer of the prepared organic EL element substrate using a spinner so that the film thickness after curing would be 0.1 μm. The composition was then cured by heating in a heating oven at 100°C for 10 minutes to form a planarizing film (not shown in FIG. 1).

[0052] Next, a black photosensitive resin composition was applied onto the planarizing film using a spinner so that the film thickness after curing would be 0.5 μm, and the composition was exposed to ultraviolet light through a photomask with a desired pattern, developed with an alkali, washed with water, and dried to form a temporary coating that covered the non-light-emitting portions (or non-light-emitting portions) of the OLED element. The composition was then heated in a heating oven at 80°C for 10 minutes to be cured, forming a light-shielding layer (or BM: black matrix).

[0053] Next, a green photosensitive resin composition was applied onto the light-shielding layer using a spinner so that the film thickness after curing would be 1.0 μm, and the composition was exposed to ultraviolet light through a photomask with the desired pattern, developed with an alkali, washed with water, and dried to temporarily form a green layer (G) with a pixel size of 2.4 μm × 2.4 μm. The green layer (G) was then cured by heating at 80°C for 10 minutes in a heating oven.

[0054] Next, in the same manner as in the formation of the green layer (G), a red photosensitive resin composition was applied using a spinner so that the film thickness after curing would be 1.0 μm, and the red layer (R) was temporarily formed with a pixel size of 2.4 μm × 2.4 μm through UV exposure, alkali development, water washing, and drying processes using a photomask with the desired pattern. The red layer (R) was then heated in a heating oven at 80 °C for 10 minutes to be cured, forming the red layer (R).

[0055] Next, in the same manner as in the formation of the green layer (G), a red photosensitive resin composition was applied using a spinner so that the film thickness after curing would be 1.0 μm, and then the resulting blue layer (B) was temporarily formed after UV exposure through a photomask with the desired pattern, alkali development, water washing, and drying processes, with a pixel size of 2.4 μm × 2.4 μm. The blue layer (B) was then cured by heating at 80 ° C for 10 minutes in a heating oven, completing the formation of the color filter.

[0056] Furthermore, a cover glass was attached to the color filter using a sealant, Structbond XMF-T-107 (manufactured by Sumitomo Chemical Co., Ltd.), to prepare an organic EL display device.

[0057] <Comparative Example 1> An organic EL display device was produced in the same manner as in Example 1, except that no light-shielding layer was formed and the thicknesses of the red, green, and blue layers of the color filter were set to 1.2 μm.

[0058] <Color reproducibility evaluation> The organic EL display devices prepared in Example 1 and Comparative Example 1 were placed next to each other, and when only red, only green, and only blue were simultaneously displayed, the vividness of the red, green, and blue colors was compared visually. As a result, the organic EL display device prepared in Example 1 clearly displayed more vivid red, green, and blue. Therefore, it was found that the organic EL display device prepared in Example 1 had better color reproducibility. This is thought to be because the position of the light-shielding layer was closer to the light-emitting element, which blocked more of the obliquely emitted light from the light-emitting element and reduced the light that passed through adjacent pixels, thereby suppressing color mixing.

[0059] A second embodiment of the present invention will be described with reference to Figures 3 and 4. In the following description, components common to those already described will be assigned the same reference numerals and duplicated description will be omitted.

[0060] 3 is a schematic cross-sectional view showing an organic EL display device 30 according to this embodiment. The organic EL display device 30 differs from the first embodiment only in that it includes a light-shielding layer 50 instead of the light-shielding layer 15. The shape of the light-shielding layer 50 in a plan view is generally similar to that of the light-shielding layer 15, but the shape of a cross section (widthwise cross section) perpendicular to the extension direction of the light-shielding layer 50 is significantly different.

[0061] 4 shows an enlarged cross-sectional shape of the light-shielding layer 50. The light-shielding layer 50 has a lower portion 53, a middle portion 52, and an upper portion 51 from the sealing layer 7 side. The upper surface of the upper portion 51 in cross section has a curved shape, more specifically, a substantially hemispherical shape, with the highest point being the middle portion in the width direction. The cross-sectional shape of the intermediate portion 52 is tapered (hereinafter referred to as "reverse tapered") so that the width gradually decreases from the boundary with the upper portion 51 toward the lower portion 53. The cross-sectional shape of the lower portion 53 is tapered (hereinafter referred to as a "forward tapered shape") such that the width gradually increases from the boundary with the intermediate portion 52 toward the sealing layer 7.

[0062] The width of the middle portion 52 is greatest at the connection with the upper portion 51, and the value W1 (maximum width of the middle portion, maximum width of the upper portion) is approximately the same as the maximum width of the upper portion 51. The width dimension of the intermediate portion 52 is smallest at the connection portion with the lower portion 53, and the value W2 (minimum width of the intermediate portion) is approximately the same as the minimum width dimension of the lower portion 53. The width dimension of the lower portion 53 is greatest at the lower end portion in contact with the sealing layer 7, and the value W3 (maximum width of the lower portion) is smaller than the above-mentioned W1.

[0063] The organic EL display device 30 according to this embodiment can effectively block oblique light emitted from the light-emitting elements, similar to the first embodiment. Furthermore, by providing the light-shielding layer 50 having the above-described configuration, the following advantageous effects can be achieved. First, because the upper surface of the upper portion 51 has a convex curved cross-sectional shape, when the colored resin composition that will become the color filter 25 after the formation of the light-shielding layer 50 is applied, the liquid composition is less likely to remain on the light-shielding layer 50, and the composition flows suitably into the openings of the light-shielding layer. As a result, the coatability of the colored resin composition is improved.

[0064] Next, since the intermediate portion 52 is inversely tapered and the maximum width W3 of the lower portion 53 is smaller than the width W1, the opening size of the light-shielding layer is larger on the lower side closer to the light-emitting element. As a result, more light from the light-emitting element can be guided to the color filter 25, improving the light extraction efficiency.

[0065] Furthermore, since lower portion 53 has a forward tapered shape, the contact area with sealing layer 7 is increased compared to a straight shape in which the width dimension does not change. As a result, adhesion to sealing layer 7 is improved, and peeling from sealing layer 7 is suitably suppressed.

[0066] The light-shielding layer 50 can be easily produced by using a black photoreactive resist. First, a photoreactive resist is applied onto the sealing layer 7 to form a resist layer.

[0067] Next, this resist layer is exposed using a mask patterned to correspond to the planar shape of the light-shielding layer 50. At this time, the light rays (e.g., i-line rays with a wavelength of 365 nm) that harden the resist are irradiated more strongly at the center of the mask opening than at the periphery. As a result, the resist is sufficiently hardened at the center of the mask opening, while the effect is somewhat weaker at the periphery. When this is developed, the upper surface of the resist layer is removed relatively more near the periphery of the mask opening, resulting in the upper surface of the upper portion 51 becoming a convex spherical surface.

[0068] Because the resist is black, the amount of light reaching the resist layer decreases the closer to the bottom. Because of this, and because the light is stronger in the center than in the periphery, the width of the middle portion gradually decreases toward the bottom. As a result, the middle portion 52 has a reverse tapered shape. Furthermore, during the development process, due to factors such as the surface tension of the developer, the developer does not sufficiently reach the bottom of the light-shielding layer. As a result, the lower portion 53 has a forward tapered shape.

[0069] The light-shielding layer 50 can be manufactured by the above procedure. Post-baking may be performed as necessary. A suitable example of the black photoreactive resist described above is the photosensitive coloring composition described in JP 2020-71433 A. This composition cures at a relatively low temperature of 100°C or less. Therefore, even when a light-shielding layer is formed directly on a layer that seals the OLED, as in this embodiment, post-baking can be performed with little damage to the OLED located underneath.

[0070] In order to preferably exert the above-mentioned various effects, it is effective to make the cross-sectional shape of the light-shielding layer into a predetermined form. Regarding the effect brought about by the upper portion 51, the radius of curvature r (see FIG. 4) of the upper surface of the upper portion 51 is preferably 0.3 to 0.6 times the above W1. Regarding the effect brought about by the intermediate portion 52, it is preferable that W2 be 0.4 times or more and 0.6 times or less than W1. Regarding the effect provided by the lower portion 53, it is preferable that W3 be 0.5 to 0.7 times W1 and larger than W2.

[0071] An example of the second embodiment will be described. Example 2 A light-shielding layer having an upper portion, a middle portion, and a lower portion was produced by performing exposure and development under different conditions using BLKR-1 similar to that used in Example 1. The other points were the same as those in Example 1, and an organic EL display device according to Example 2 was produced. The organic EL display device according to Example 2 was cut to expose the widthwise cross section of the light-shielding layer, which was then photographed with a scanning electron microscope (SEM). Using the multiple images obtained, the dimensions of each part in the cross-sectional shape of the light-shielding layer were measured, and the results were as follows: The radius of curvature r of the upper surface was between 0.33 and 0.53 times W1. W2 was between 0.47 and 0.53 times W1. W3 was between 0.59 and 0.69 times that of W1. From the above, it was confirmed that the light-shielding layer according to the second embodiment can actually be manufactured.

[0072] Although the embodiments and examples of the present invention have been described above, the specific configuration is not limited to these embodiments, and configuration changes and combinations within the scope of the gist of the present invention are also included. Some examples of changes are shown below, but these are not all inclusive, and other changes are also possible. Two or more of these changes may be combined as appropriate.

[0073] 3 shows an example in which the upper ends of the light-shielding layer and the color filters are at approximately the same height, but this is not essential, and it is sufficient if the surface of the light-shielding layer facing the light-emitting elements is at the same position as the surface of the color filters facing the light-emitting elements, or is closer to the light-emitting elements. Therefore, a light-shielding layer 50A lower than the color filters 25 may be provided, as in a modified organic EL display device 30A shown in FIG.

[0074] The light-shielding layer and color filter of this embodiment are not limited to those formed directly on the light-emitting element substrate, as in the above-described embodiment. For example, a substrate made of a resin film or the like may be prepared, and the light-shielding layer and colored pixels may be formed on this substrate. By bonding such a color filter substrate to the light-emitting element substrate with an adhesive or the like, it can be used as a component of a display device other than an organic EL display device. In this case, as long as the light-shielding layer extends across the thickness of the color filter, whether the upper or lower side of the light-shielding layer faces the light source, the oblique light blocking effect is roughly the same. Because the color filter substrate is not near light-emitting elements during the manufacturing process, black resist, which is post-baked at high temperatures, can be used as the light-shielding layer material without any problems. [Explanation of symbols]

[0075] 1. Glass substrate 2 Colored pixel (red) (red colored pixel) 3 Colored pixel (green) (green colored pixel) 4 Colored pixel (blue) (blue colored pixel) 6 Resin layer 7 Sealing layer 8 light-emitting element (red) 9 Light-emitting element (green) 10 Light-emitting element (blue) 11 Light-emitting element 12 Drive circuit board 13 Color filter substrate 14 Light emitting element substrate 15, 50, 50A Light-shielding layer 20, 30, 30A organic EL display device 25 Color Filters

Claims

1. An organic EL display device comprising: a light emitting element substrate on which light emitting elements are formed at predetermined positions on a drive circuit substrate on which a drive circuit is formed on a semiconductor substrate; and a color filter including at least red, green, and blue colored pixels at positions corresponding to each light emitting element on the light emitting element substrate in a plan view, a light-shielding layer is formed across the boundaries of the colored pixels in a position where it does not overlap with the light-emitting element in a plan view; In a cross-sectional view, a surface of the light-shielding layer facing the light-emitting element is disposed at the same position as a surface of the color filter facing the light-emitting element or at a position facing the light-emitting element, The light-shielding layer is an upper portion having a convex curved upper surface; a reverse tapered intermediate portion provided below the upper portion and gradually decreasing in width as it extends downward; a forward tapered lower portion provided below the intermediate portion and having a width gradually increasing toward the light emitting element; Organic EL display device.

2. The radius of curvature of the curved surface is 0.3 to 0.6 times the maximum dimension in the width direction of the intermediate portion, The organic electroluminescence display device according to claim 1 .

3. The minimum width of the intermediate portion is 0.4 to 0.6 times the maximum width of the intermediate portion. The organic electroluminescence display device according to claim 1 .

4. The maximum width of the lower portion is smaller than the maximum width of the upper portion. The organic electroluminescence display device according to claim 1 .

5. The maximum width of the lower portion is 0.5 to 0.7 times the maximum width of the upper portion. The organic electroluminescence display device according to claim 4 .

6. a sealing layer is further provided between the light-emitting element and the color filter, A part of the light-shielding layer is embedded in the sealing layer. The organic electroluminescence display device according to claim 1 .

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