Display device

Abstract

To provide a display device that can more effectively suppress occurrence of moire and has excellent visibility.SOLUTION: A display device comprises: a reflection type display device; and a direct irradiation type illumination section for applying light to the reflection type display device. The reflection type display device includes a reflection pixel electrode with a periodical pattern. The direct irradiation type illumination section is an organic electroluminescence element including a positive electrode, an organic layer, and a negative electrode having periodicity toward a visible side, and has a light scanning layer on a visible side relative to the reflection type display device and in the reflection type display device side relative to the direct irradiation type illumination section. When the pitch of the negative electrode is P1, the pitch of the reflection pixel electrode is P2, the shortest distance from the light scanning layer to the reflection pixel electrode is D1, the shortest distance from the light scattering layer to the negative electrode is D2, and the scanning angle of the light scattering layer is θ1, the following relational expression (1) and the following relational expression (2) are established: (1)P2≤2×D1×tan(θ1 / 2, (2)P1≤2×D2×tan(θ1 / 2).SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a display device. [Background technology]

[0002] Mobile devices such as smartphones that use liquid crystal display devices are used in both environments where there is strong external light, such as outdoors during the day, and environments where there is no external light, such as outdoors at night or indoors. In such usage environments, a reflective liquid crystal display device has been proposed that is capable of ensuring sufficient contrast even in environments with strong external light, such as outdoors during the day, and also capable of displaying even in environments without external light. This reflective liquid crystal display device is equipped with a sidelight-type front light in which a light source is arranged on the side of a light guide plate (for example, Patent Document 1).

[0003] A reflective LCD display device equipped with a sidelight type front light irradiates light from a side light source onto the liquid crystal side by controlling the shape of the shaped portion of the light guide plate and the refractive index of that shaped portion. However, it is not possible to completely prevent some of the refracted light within the light guide plate from leaking toward the viewer, which reduces the contrast of the LCD display.

[0004] To solve this problem, display devices have been proposed that include a direct illumination unit using an organic electroluminescence element on the viewer side, as in Patent Documents 2 and 3. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-258358 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-323303 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-154402 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when the inventors verified the relationship when the pitch between the patterns of the cathode, which is of a stripe type or a grid type in the lighting unit, is P1 and the pitch between the patterns of the pixel electrodes (or reflective pixel electrodes) is P2, there is a problem that light traveling from the lighting device toward the reflective LCD and light traveling from the LCD liquid crystal toward the lighting device (the viewing side) interfere with each other and interference fringes occur when "P1 ≠ P2", when "P1 < P2 and P1 / P2 ≠ 1 / natural number", or when "P1 > P2 and P1 / P2 ≠ natural number".

[0007] Therefore, an object of the present invention is to provide a display device that can more effectively suppress the occurrence of moiré (or interference fringes), which is periodic luminance unevenness that occurs when different periodic patterns overlap, regardless of the relationship between the pitch between the patterns of the cathode in the direct illumination unit and the pitch between the patterns of the reflective pixel electrodes, by incorporating a specific light-scattering layer inside the reflective display device or between the reflective display device and the direct illumination unit.

Means for Solving the Problem

[0008] One aspect of the present disclosure is an organic electroluminescent display comprising: a reflective display device; and a direct-type illumination unit disposed on a viewing side of the reflective display device and irradiating the reflective display device with light, wherein the reflective display device includes, facing the viewing side, a third transparent substrate, reflective pixel electrodes disposed on the viewing side surface of the third transparent substrate in a periodic pattern, and a fourth transparent substrate opposed to the third transparent substrate; and the direct-type illumination unit includes, facing the viewing side, a first transparent substrate, an anode, an organic layer, a cathode disposed on the viewing side in a periodic pattern, and a second transparent substrate opposed to the first transparent substrate. the organic layer includes an emitting layer, and is provided with a light-scattering layer on the viewing side of the fourth transparent substrate and on the reflective display device side of the first transparent substrate, and at least the following relational expressions (1) and (2) hold when the pitch between the patterns of the cathode is P1, the pitch between the patterns of the reflective pixel electrodes is P2, the shortest distance from the viewing side surface of the light-scattering layer to the viewing side surface of the reflective pixel electrodes is D1, the shortest distance from the surface of the light-scattering layer facing the reflective pixel electrodes to the surface of the cathode facing the reflective pixel electrodes is D2, and the scattering angle of light incident on the light-scattering layer is θ1. (1) P2≦2×D1×tan(θ1 / 2) (2) P1≦2×D2×tan(θ1 / 2) It is preferable that one of P1 and P2 is a natural number multiple of the other. It is preferable that one of P1 and P2 is a natural number multiple of the other. The light scattering layer is preferably an anisotropic light scattering layer in which the amount of emitted light changes depending on the angle of incidence of light. The light scattering layer is preferably an isotropic light scattering layer in which the amount of emitted light does not change depending on the angle of incidence of light. The anisotropic light-scattering layer preferably has a matrix region and a structure region that is provided in the matrix region, extends in the thickness direction of the matrix region, and has a refractive index different from that of the matrix region. The structural region is preferably a plurality of columnar structures extending in the thickness direction of the matrix region. The anisotropic light-scattering layer has a central scattering axis that is an axis of symmetry regarding light scattering, and it is preferable that the central scattering axis angle θ2, which is the angle between the normal to the anisotropic light-scattering layer and the central scattering axis, is 0° to 40°. The display device preferably has a cathode antireflection layer on the viewing side of the cathode for blocking light reflected from the cathode. [Effects of the Invention]

[0009] According to the present invention, it is possible to more effectively suppress the occurrence of moire and provide a display device with good visibility. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing a stripe pattern as an example of a cathode and a cathode antireflection layer in the technology disclosed herein, in which the display unit of the display device is viewed from the viewing side for a direct illumination unit. [Figure 2] FIG. 1 is a schematic diagram showing a grid pattern as an example of a cathode and a cathode antireflection layer in the technology disclosed herein, in which the display unit of the display device for a direct illumination unit is viewed from the viewing side. [Figure 3] FIG. 10 is a schematic diagram showing an island pattern as an example of a cathode and a cathode antireflection layer in the technology disclosed herein, in which the display unit of the display device for a direct illumination unit is viewed from the viewing side. [Figure 4] 4 is a schematic diagram illustrating the relationship in size between the cathode antireflection layer and the cathode in the AA cross section, A'-A' cross section, or A''-A'' cross section of each of the display devices shown in FIGS. 1 to 3. FIG. [Figure 5] FIG. 1 is a schematic diagram illustrating the cross-sectional structure of a display device in Example 1 of the implementation form of the present disclosure, and is a diagram illustrating the direction of travel of light within the display device, where light from a direct-type illumination unit is reflected by a reflective pixel electrode via a scattering layer and passes through the direct-type illumination unit. [Figure 6] 1 is a scattering profile for explaining the scattering angle in an anisotropic light-scattering layer according to the present disclosure. [Figure 7]1A and 1B are schematic cross-sectional and top views of an anisotropic light-scattering layer according to the present disclosure, illustrating an example of the structure of the anisotropic light-scattering layer. [Figure 8] 1 is a graph showing an example of an optical profile of an anisotropic light-scattering layer according to the present disclosure. [Figure 9] FIG. 1 is a conceptual diagram illustrating a method for creating an optical profile in an anisotropic light-scattering layer according to the present disclosure. [Figure 10] 10 is a schematic diagram illustrating a cross-sectional structure of a display device according to a second embodiment of the present disclosure. FIG. [Figure 11] FIG. 10 is a schematic diagram of a display device according to a third embodiment of the present disclosure, viewed from the viewing side, showing the relationship between (a) a cathode and an anode-connecting electrode, (b) an anode and an anode-connecting electrode, and (c) a cathode antireflection layer in x and y coordinates. [Figure 12] 12 is a schematic diagram illustrating a cross-sectional structure of the FF cross section of FIG. 11 in a display device according to a third embodiment of the present disclosure. FIG. [Figure 13] 12 is a schematic diagram illustrating a cross-sectional structure of the E-E cross section of FIG. 11 in a display device according to a third embodiment of the present disclosure. FIG. [Figure 14] 10 is a schematic diagram illustrating a cross-sectional structure of a display device according to a fourth embodiment of the present disclosure. FIG. [Figure 15] FIG. 10 is a schematic diagram illustrating a cross-sectional structure of a display device according to a fifth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described in detail, but the present disclosure is not limited to the following.

[0012] In this specification, the expression "u to v" in the description of a numerical range means that the range is from u to v, unless otherwise specified.

[0013] In this specification, expressions relating to the shape or state of an object do not indicate the strict shape or state, but indicate the shape or state to the extent that it is recognized as common general knowledge in the art. For example, the expression "parallel" does not indicate that something is strictly "parallel," but rather that it is "parallel" to the extent that it is recognized as "parallel" in the art.

[0014] In the specification, "transparent" means that the transmittance of visible light is 50% or more, preferably 80% or more, more preferably 90% or more, and even more preferably 99% or more. The transmittance of visible light can be measured using an ultraviolet-visible spectrophotometer.

[0015] <<<<Display device>>>> The display device of the present disclosure includes a reflective display device and a direct illumination unit that is arranged (stacked) on the viewing side of the reflective display device and irradiates the reflective display device with light.

[0016] In this specification, when expressed in an xyz Cartesian coordinate system, the z-axis direction indicates the direction perpendicular to the main surface of the reflective display device or direct illumination unit, and the plane having the z-axis direction as its normal direction is referred to as the xy plane. Note that the x-axis and y-axis directions are arbitrary.

[0017] The direct-type illumination unit is disposed such that the first transparent substrate side of the direct-type illumination unit (described later) faces the display unit of the reflective display device. The direct-type illumination unit is preferably disposed close to the reflective display device. If an air gap exists between the direct-type illumination unit and the reflective display device, when light emitted from the first transparent substrate enters the air gap, it is reflected by the surface of the first transparent substrate facing the reflective display device (or inside the first transparent substrate) and returns to the observer, reducing the contrast of the display unit of the display device. Therefore, if an air gap exists between the direct-type illumination unit and the reflective display device, it is preferable to eliminate the air gap by laminating a resin layer or the like having a refractive index similar to that of the first transparent substrate.

[0018] The material of the resin layer is not limited as long as it has a refractive index similar to that of the first transparent substrate, and examples thereof include polycarbonate, polymethyl methacrylate, polyethylene terephthalate, and triacetyl cellulose.

[0019] The light-scattering layer is laminated on the viewing side of a fourth transparent substrate of a reflective display device (described later) and on the reflective display device side of a first transparent substrate of a direct illumination unit. The light-scattering layer may be laminated between the reflective display device and the direct illumination unit, or may be included inside the reflective display device.

[0020] The direct illumination unit and the reflective display device can be connected and bonded (or laminated) using known methods, such as a bonding method using a pressure-sensitive adhesive (or a pressure-sensitive adhesive sheet, a pressure-sensitive adhesive layer, etc.) or an adhesive (or an adhesive sheet, a pressure-sensitive adhesive layer, etc.). There are no particular limitations on the pressure-sensitive adhesive or adhesive, as long as it is transparent, and known pressure-sensitive adhesives can be used.

[0021] <<<Direct lighting section>>> The direct-type illumination unit is an organic electroluminescence element including, facing the viewing side, a first transparent substrate, an anode, an organic layer, a cathode arranged in a periodic pattern, and a second transparent substrate facing the first transparent substrate. The organic layer includes a light-emitting layer. The direct-type illumination unit is disposed in the display device with the first transparent substrate side facing the reflective display device.

[0022] <<First Transparent Substrate and Second Transparent Substrate>> The first transparent substrate and the second transparent substrate will be described with reference to FIG. The materials for the first transparent substrate 260 and the second transparent substrate 210 are not particularly limited as long as they do not impede the effects of the disclosed technology, but glass substrates such as alkali-free glass are used.

[0023] The thickness of the first transparent substrate is preferably 0.6 mm or less, more preferably 0.3 mm or less. This allows the direct-view illumination unit to be thinner and lighter, making the entire display device lighter, thinner, shorter, and smaller. Furthermore, it also allows light emitted from the organic layer to efficiently reach the reflective display. To make the thickness of the glass substrate 0.3 mm or less, after the direct-view illumination unit is assembled (with both surfaces made of glass), the glass substrate is thinned by glass etching, glass polishing, or the like.

[0024] The first transparent substrate and the second transparent substrate may be transparent resin substrates. A case where transparent resin substrates are used as the first transparent substrate and the second transparent substrate will be described with reference to Fig. 14. In this specification, the first transparent substrate and the second transparent substrate using a transparent resin substrate may be referred to as the first transparent resin substrate and the second transparent resin substrate, respectively. A highly heat-resistant resin substrate such as polyimide can be used as the first transparent resin substrate 265. A second thin-film sealing layer 271 is formed on the viewing side of the first transparent resin substrate 265 to prevent impurities such as moisture from entering the anode 250, the organic layer 240, and the cathode 230. A resin substrate such as polyimide or PET (polyethylene terephthalate) can be used as the second transparent resin substrate 215. The first transparent resin substrate and the second transparent resin substrate may be made of the same material or different materials. The direct-view illumination unit using the first transparent resin substrate 265 and the second transparent resin substrate 215 is manufactured as follows. A UV release agent is applied to a glass substrate, and then a resin such as polyimide is applied and cured. A thin-film sealing layer (described later) is formed on top of this, followed by the anode, organic layer, cathode, and thin-film sealing layer (described later) in that order. The second transparent resin substrate 215 is then laminated, and the device is then irradiated with ultraviolet light and the glass substrate is peeled off to complete the device. Examples of UV release agents include Coponyl manufactured by Mitsubishi Chemical Corporation.

[0025] The thickness of the resin layers of the first transparent resin substrate 265 and the second transparent resin substrate 215 is preferably 30 μm to 300 μm, and more preferably 50 μm to 150 μm, which satisfies both the requirements for lightness, thinness, smallness and strength.

[0026] <<Anode / Anode connecting electrode>> The direct illumination unit can include, in addition to the anodes, an anode connecting electrode that connects the anodes to each other. The anode and anode-connecting electrode will be described with reference to FIG. 5. An anode 250 is laminated on the viewing side (second transparent substrate 210 side) of the first transparent substrate 260, either directly or via another layer. The anode 250 may be formed in a periodic pattern, or may be formed so as to cover the entire surface of the first transparent substrate 260. When a pattern is formed as the anode 250, it may be the same pattern as that of the cathode described below, or a different pattern.

[0027] In order to prevent interfacial reflection from the anode 250 (particularly when a material with a high refractive index such as indium tin oxide or indium zinc oxide is used) with respect to the pattern of the cathode 230 and to improve the visibility of the display device, it is preferable that the pattern of the anode 250 and the pattern of the cathode 230 be similar (that is, the positions of the anode 250 and the cathode 230 on each xy plane and the shapes on the same plane be substantially identical).

[0028] The anode 250 is a transparent electrode, and its material is not particularly limited as long as it does not impair the effects of the disclosed technology, but may be, for example, indium tin oxide (ITO), indium zinc oxide (IZO), or the like.

[0029] The thickness of the anode 250 is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 10 nm to 1000 nm, and more preferably 50 nm to 500 nm.

[0030] The anode 250 can be formed by sputtering a transparent electrode material onto the surface of the first transparent substrate, or by vacuum deposition or other methods. When patterning the anode, the desired pattern can be formed by photoetching after film formation. Alternatively, a metal mask can be used during vacuum deposition to form the pattern.

[0031] When the anodes 250 are formed in a pattern such as a stripe pattern, an anode-connecting electrode 251 can be provided to connect the patterned anodes 250 to each other in order to prevent a voltage drop in the anodes 250. The anode-connecting electrode 251 can be formed from the same material and by the same manufacturing method as the cathode 230, and has the same thickness as the cathode 230.

[0032] The anode connecting electrode will be described with reference to Figs. 11 to 13. Fig. 11 shows an example of a conceptual diagram of a direct illumination unit, illustrating the structure of a third embodiment described below. Fig. 11 is a view of the anode 250, cathode 230, and anode connecting electrode 251 of the third embodiment, viewed from the viewing side. Fig. 11(b) illustrates the anode 250 and the anode connecting electrode 251, with adjacent anodes 250 formed in a stripe pattern being connected by the anode connecting electrode 251. Connecting the stripe-shaped anodes 250 by the anode connecting electrode 251 makes it possible to apply a sufficient voltage to the anodes 250, thereby preventing voltage drop.

[0033] 12 is a cross-sectional view of the display device 1b taken along the FF cross section of FIG. 11. The direct illumination unit 200 includes, from the viewing side, a first transparent substrate 260, anodes 250 arranged in a periodic striped pattern, an organic layer 240, and cathodes 230 arranged in a periodic striped pattern. The anodes 250 formed in the striped pattern are connected to each other by anode-connecting electrodes 251. The anodes 250, anode-connecting electrodes 251, organic layer 240, and cathodes 230 are covered with a first thin-film sealing layer 270. A cathode antireflection layer 220 is laminated on the viewing side of the first thin-film sealing layer 270 so as to cover the cathodes 230 and anode-connecting electrodes 251, and a second transparent substrate 210 is further laminated on the viewing side of the first thin-film sealing layer 270. The anode 250, organic layer 240, and cathode 230 are formed on the first transparent substrate 260 by vapor deposition using a metal mask, but the anode-connecting electrode 251 is formed using a metal mask with a predetermined pattern at the same time as the formation of the cathode 230. Therefore, the anode-connecting electrode 251 is made of the same material as the cathode 230, and has approximately the same thickness. Compared with ITO or IZO, which are the materials of the anode 250, Al and the like used for the cathode 230 have low electrical resistance, and therefore the anode-connecting electrode 251 can prevent a voltage drop in the voltage applied to the anode 250. This reduces the power consumption of the lighting device, and this effect becomes more pronounced the larger the area of ​​the lighting device. The cathode 230 and the anode-connecting electrode 251 are preferably thicker to reduce voltage drop, but if they are too thick, distortion of the shape occurs and material costs rise. For these reasons, the thickness is preferably 10 nm to 1000 nm, and more preferably 30 nm to 500 nm.

[0034] <<Organic layer>> The organic layer is formed on the visible side (cathode side) of the anode by a method using vacuum deposition, inkjet printing, or the like. The organic layer comprises a hole transport layer, a light-emitting layer, an electron transport layer, etc. For example, a device manufactured by Canon Tokki Corporation can be used for the vacuum deposition method, and a device manufactured by Tokyo Electron Limited can be used for inkjet printing.

[0035] The organic layer may be formed into a periodic pattern similar to that of the anode, or may be formed into a substantially uniform layer so as to cover the surface of the anode. In the case of vacuum deposition, the pattern is formed by vacuum deposition using a metal mask.

[0036] The thickness of the organic layer is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 8 nm to 2200 nm, and more preferably 10 nm to 500 nm.

[0037] The organic layer is not particularly limited as long as it includes an emitting layer, but the organic layer may have any of the following structures: a single-layer structure including only an emitting layer; a two-layer structure in which a hole transport layer and an emitting layer are stacked in this order from the anode toward the viewing side; a three-layer structure in which a hole transport layer, an emitting layer, and an electron transport layer are stacked in this order from the anode toward the viewing side; or a multilayer structure including other functional layers in addition to the three-layer structure. The other functional layers are not particularly limited as long as they do not impair the effects of the disclosed technology. For example, an electron blocking layer can be stacked between the hole transport layer and the emitting layer, or a hole blocking layer can be stacked between the emitting layer and the electron transport layer.

[0038] In a method for forming an organic layer using vacuum deposition, the organic layer can be formed by laminating the materials of each layer included in the organic layer in a desired order while vacuum depositing them. When forming a pattern in the organic layer, the pattern can be formed by using a mask during deposition. When forming a pattern on the organic layer and the anode, it is preferable that the organic layer be larger than the anode so as to cover the anode, or be larger than the cathode, in order to prevent contact between the cathode and the anode.

[0039] <Hole transport layer> The hole transport layer is used to efficiently transport holes injected from the anode toward the light-emitting layer. The material of the hole transport layer is not particularly limited, and any known material can be used as long as it is transparent and does not impair the effects of the disclosed technology. Examples of materials for the hole transport layer include triazole derivatives, oxadiazole derivatives, imidazole derivatives, carbazole derivatives, indolocarbazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, allylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers such as thiophene oligomers. These materials can be used alone or in combination in any ratio.

[0040] The thickness of the hole transport layer is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 5 nm to 1000 nm, and more preferably 5 nm to 200 nm.

[0041] <Light-emitting layer> The light-emitting layer contains a light-emitting material, and when a voltage is applied between the anode and cathode, holes and electrons injected from each electrode recombine in the light-emitting layer, causing the light-emitting material to enter an excited state. The light emitted from the excited light-emitting material is released to the outside, causing the organic electroluminescence element to emit light. The light-emitting layer may also serve as a hole transport layer. The light-emitting layer is transparent.

[0042] The material for the light-emitting layer is not particularly limited as long as it does not impair the effects of the disclosed technology, and known materials can be used, such as epidolidine, 2,5-bis[5,7-di-t-pentyl-2-benzoxazolyl]thiophene, 2,2'-(1,4-phenylenedivinylene)bisbenzothiazole, 2,2'-(4,4'-biphenylene)bisbenzothiazole, 5-methyl-2-{2-[4-(5-methyl-2-benzoxazolyl)phenyl]vinyl}benzoxazole, 2,5-bis(5-methyl-2-benzoxazolyl)thiophene, anthracene, naphthalene, phenanthrene, pyrene, chrysene, perylene, perinone, and 1,4-diphenylbutadiene. Examples of suitable oxidizing agents include benzophenone, tetraphenylbutadiene, coumarin, acridine, stilbene, 2-(4-biphenyl)-6-phenylbenzoxazole, aluminum trisoxine, magnesium bisoxine, bis(benzo-8-quinolinol)zinc, bis(2-methyl-8-quinolinolate)aluminum oxide, indium trisoxine, aluminum tris(5-methyloxine), lithium oxine, gallium trisoxine, calcium bis(5-chlorooxine), polyzinc-bis(8-hydroxy-5-quinolinolyl)methane, dilithium epindolinone, zinc bisoxine, 1,2-phthaloperinone, and 1,2-naphthaloperinone. These may be used alone or in combination in any desired ratio.

[0043] The thickness of the light-emitting layer is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 1 nm to 200 nm, and more preferably 1 nm to 100 nm.

[0044] <Electron transport layer> The electron transport layer is used to efficiently transport electrons injected from the cathode toward the light-emitting layer. The electron transport layer is transparent and can be used as a hole-blocking layer. The material of the electron transport layer is not particularly limited, and known materials can be used as long as they do not impair the effects of the disclosed technology. Examples of such materials include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethanes, anthrone derivatives, oxadiazole derivatives, azole derivatives, and azine derivatives. These materials can be used alone or in combination in any ratio.

[0045] The thickness of the electron transport layer is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 2 nm to 1000 nm, more preferably 2 nm to 500 nm, and even more preferably 5 nm to 200 nm.

[0046] <<Cathode>> The cathode is disposed on the organic layer in a periodic pattern, and is formed so as not to come into direct contact with the anode via the organic layer.

[0047] The material of the cathode is not particularly limited as long as it does not impair the effects of the disclosed technology, and any known material can be used. For example, a metal single layer of aluminum, magnesium, silver, calcium, or the like, or a metal laminate in which these metal single layers are laminated, can be used. Most of the light traveling from the light-emitting layer toward the viewing side is reflected downward by the cathode and irradiated onto the reflective display device through the transparent anode and the first transparent substrate. This minimizes the direct entry of light from the light-emitting layer into the eyes of an observer looking toward the direct illumination unit, thereby improving the visibility of the display device. The use of aluminum or silver, which have particularly high reflectivity, is particularly effective in the disclosed technology.

[0048] The cathode is preferably thicker to reduce the voltage drop, but if it is too thick, the shape may be distorted and the material costs may increase. For these reasons, the thickness is preferably 10 nm to 1000 nm, more preferably 30 nm to 500 nm.

[0049] The periodic pattern of the cathode is formed with a constant pitch. The shape of the pattern when observed from the viewing side of the cathode is not particularly limited as long as it does not impair the effects of the disclosed technology, and examples thereof include a stripe type (see FIG. 1), a lattice type (see FIG. 2), and an island type (see FIG. 3). The cathode can be formed by laminating a cathode material on an organic layer by vacuum deposition. When a pattern is to be formed on the cathode, the pattern can be formed by using a mask during deposition.

[0050] When a voltage is applied to the cathode and anode, a part of the light-emitting layer sandwiched between the cathode and anode (the anode existing on the same z-axis as the cathode) emits light. This light-emitting region of the light-emitting layer is called the light-emitting region, and the non-light-emitting region is called the non-light-emitting region.

[0051] <<Thin film sealing layer>> The direct illumination unit may include a thin-film sealing layer. In this specification, when multiple thin-film sealing layers are used in the direct illumination unit, they may be distinguished and referred to as a first thin-film sealing layer, a second thin-film sealing layer, and so on. The thin-film sealing layer is laminated to seal the cathode, anode, anode-connecting electrode, and organic layer. The thin-film sealing layer is a transparent inorganic or organic film that can block moisture penetration. Examples of materials that can be used for the inorganic film include silicon nitride, silicon dioxide, and metal oxides, while examples of materials that can be used for the organic film include curable resins such as epoxy resins. Alternatively, a laminated film in which multiple inorganic and organic films are alternately laminated can also be used.

[0052] The thickness of the thin film sealing layer is not particularly limited as long as it does not impede the effects of the disclosed technology, but is preferably 100 nm to 1000 nm.

[0053] <<Other layers of the direct lighting section>> The direct illumination unit may have other layers laminated at desired positions as needed, such as a cathode antireflection layer, a cathode antireflection polarizing plate, an antireflection layer, a protective film, a pressure-sensitive adhesive layer, an adhesive layer, etc.

[0054] <Cathode antireflection layer> The cathode antireflection layer will be described with reference to FIG. 5 . The direct illumination unit can have a cathode antireflection layer 220 covering the cathode 230 on the viewing side of the cathode 230. The cathode antireflection layer 220 is used to prevent external light from being reflected by the cathode 230. The cathode antireflection layer 220 prevents external light from being reflected from the surface of the cathode 230 to the viewer, thereby improving the visibility of the display device. Therefore, the shape of the cathode antireflection layer 220 is not particularly limited as long as it can prevent external light from being reflected by the cathode 230, but it can have the same shape as the cathode 230 or a shape slightly larger than the cathode 230.

[0055] The material of the cathode antireflection layer 220 is not particularly limited and any known material can be used as long as it does not impair the effects of the disclosed technology. For example, a black resist in which a black pigment or a black dye is mixed into a photoresist material, or chromium oxide can be used.

[0056] The thickness of the cathode antireflection layer 220 depends on the absorbance per unit thickness of the material. When the absorbance per unit thickness of the material of the cathode antireflection layer 220 is α [ / m] and the thickness is d [m], the reflected light blocking rate R [%] from the cathode 230 is expressed by the following formula: R[%]=10 α·(d / 2) ×100 α can be adjusted by the concentration of the black pigment or black dye mixed in the resist. d can be adjusted by the solids concentration during resist application and the resist application conditions. The absorbance α and thickness d per unit thickness of the cathode antireflection layer 220 are not particularly limited as long as they do not impair the effects of the disclosed technology, but are preferably within a range of the combination of absorbance α and thickness d such that the reflected light blocking rate R is 90% or more and the thickness is 50 μm or less, which allows the layer to be formed without distortion of the shape. More preferably, the thickness is within a range of the combination of absorbance α and thickness d such that the reflected light blocking rate R is 99% or more and the thickness is 50 μm or less, which allows the layer to be formed without distortion of the shape.

[0057] To enhance the light-blocking effect, the size (width or length) of the cathode antireflection layer 220 is preferably the same as or larger than that of the cathode 230, and is preferably larger than the cathode 230 by more than 0 μm and less than 10 μm. This suppresses reflection from the edge of the cathode 230, improves the antireflection effect, and allows light from the reflective display device 100 to be transmitted efficiently.

[0058] A specific description will be given based on Fig. 4. Fig. 4 is a schematic diagram illustrating the relationship between the size of the cathode antireflection section and the size of the cathode in an AA cross-sectional view of a portion of the direct illumination unit shown in Fig. 1. In other words, it is an enlarged view of the periphery of the cathode in a cross-sectional view parallel to the z-axis of the display device shown in Fig. 1. Fig. 4 shows a cathode antireflection layer 220, a cathode 230, and a first thin-film sealing layer 270. When the lengths from the edge portion of the cathode 230 to the edge portion of the cathode antireflection layer 220 are L1 and L2, respectively, and the length in the vertical direction from the cathode 230 to the cathode antireflection layer is T1, L1 and L2 preferably fall within the ranges defined by the following formulas. 5μm>L1>0 5μm>L2>0 This makes it possible to cut off light reflected in the front direction of the cathode 230 and to sufficiently transmit light from the reflective display device 100. It is more preferable that L1 and L2 each fall within the ranges defined by the following formulas. 5μm>L1>T1 5μm>L2>T1 This makes it possible to more efficiently cut off reflected light from the cathode 230, specifically cut off reflected light at an angle of 45° inside, while still allowing sufficient transmission of light from the reflective display device 100. Here, L1 and L2 may have the same length or different lengths.

[0059] <Polarizing plate for cathode antireflection> The cathode antireflection polarizing plate will be described with reference to Fig. 10. A cathode antireflection polarizing plate 290 can be used on the viewing side of the second transparent substrate 210 without forming the cathode antireflection layer 220. The cathode antireflection polarizing plate 290 is not particularly limited as long as it does not impair the effects of the disclosed technology, and a known one can be used.

[0060] The single transmittance (light transmittance of a single polarizing plate) of the cathode anti-reflection polarizing plate 290 is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 40% or more, more preferably 43% or more. The cathode anti-reflection polarizing plate 290 is arranged so that the light transmission axis thereof is preferably within ±5°, more preferably within ±1°, of parallel to the light transmission axis of the polarizing plate 110 of the reflective display device 100. This arrangement makes it possible to more efficiently cut reflected light from the cathode 230 and to sufficiently transmit light from the reflective display device 100.

[0061] <Anti-reflection layer> An anti-reflection layer can be laminated on the outermost surface of the direct illumination unit on the viewing side to prevent reflection of external light. The anti-reflection layer is not particularly limited as long as it does not impair the effects of the disclosed technology, and any known anti-reflection layer can be used.

[0062] <<About the cathode and cathode anti-reflection layer patterns>> 1 to 3 are top views of the cathode 230 of the direct illumination unit of the display device 1 (see FIG. 1), the display device 1′ (see FIG. 2), and the display device 1″ (see FIG. 3), respectively, when observed from the viewing side. In these figures, the cathode antireflection layer 220 is provided on the viewing side, but as described above, display devices having a structure without the cathode antireflection layer 220 are also included in the present invention. 1 to 3 show an example of the pattern shape of the cathode antireflection layer 220 indicated by diagonal lines and the cathode 230 present on the back side of the cathode antireflection layer 220 in the drawing.

[0063] The stripe-type cathode pattern shown in FIG. 1 is a pattern of identical straight lines arranged in parallel at equal intervals, and is arranged so as to spread out uniformly when the display unit of the display device is viewed.

[0064] The stripe-shaped cathode 230 pattern makes it easy to supply power from an external source and can reduce resistance, thereby preventing voltage drop. In Fig. 1, the cathode antireflection layer 220 is formed to cover the cathode 230. This makes it possible to efficiently suppress reflection of external light on the cathode 230.

[0065] The size of the stripes of the cathode 230 can be determined arbitrarily in accordance with the display size of the display unit.

[0066] The width of the stripes of the cathode 230 (corresponding to W1 in FIG. 1) is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less, which can suppress voltage drop and allow light from the reflective display device 100 to transmit efficiently.

[0067] The pitch P1 of the pattern of the stripe-type cathode 230 is the distance between the center lines of adjacent stripes along the longitudinal direction. Specifically, in the stripe-type cathode pattern in FIG. 1, if the center line of one stripe along the longitudinal direction is C1 and the center line of the adjacent stripe along the longitudinal direction is C2, the distance between C1 and C2 is the pitch P1. The stripe pitch P1 is 200 μm or less, preferably 100 μm or less, and more preferably 50 μm or less. By using such a stripe pitch, the cathode 230 cannot be visually recognized, and therefore, when used in the direct illumination unit 200, a display device with excellent visibility can be obtained.

[0068] The larger the light-transmitting area (the area that transmits light without the cathode 230 or cathode antireflection layer 220) of the direct illumination unit 200, the more efficiently the display light from the reflective display device can be transmitted. When the ratio of the area of ​​the light-transmitting area to the entire area of ​​the direct illumination unit 200 is defined as the aperture ratio, the aperture ratio is preferably 60% or more, more preferably 85% or more, and even more preferably 95% or more. The widths of the cathode 230 and the cathode antireflection layer 220 (the width of the cathode antireflection layer 220 is, for example, B1 in FIG. 1 ) and the pattern pitch are set so as to satisfy the above conditions.

[0069] In a direct-type illumination unit 200 employing a stripe-shaped cathode 230, each line of the cathode 230 is connected (electrically connected) at the end (end on the xy plane) of the direct-type illumination unit 200 during pattern formation, so that a voltage is applied to the entire cathode 230.

[0070] The grid-type cathode 230 pattern shown in FIG. 2 is a grid-like arrangement of cathodes 230 that are arranged perpendicular to each other, and are arranged so as to spread uniformly when the display unit of the display device is viewed.

[0071] The size of the grid of the cathode 230 can be determined arbitrarily in accordance with the display size of the display unit.

[0072] The width of one lattice (e.g., W2 in FIG. 2) and the width of another lattice (e.g., W2' in FIG. 2) in the pattern of the lattice-type cathode 230 are similarly not particularly limited as long as they do not impair the effects of the disclosed technology, and may be the same width or different widths. The width of the lattice portions (W2, W2') is not particularly limited as long as they do not impair the effects of the disclosed technology, but is preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less.

[0073] The pattern pitch P1 of the lattice cathode 230 is the distance between the center lines of adjacent lattices along the longitudinal direction. Specifically, in the pattern of the lattice cathode 230 in Fig. 2, if the center line of one lattice along the longitudinal direction is C1' and the center line of the adjacent lattice along the longitudinal direction is C2', the distance between C1' and C2' is defined as pitch P1.

[0074] In addition, in the pattern of the lattice-type cathode 230 in Figure 2, if the center line along the longitudinal direction of one lattice that is perpendicular to C1' is defined as C3' and the center line along the longitudinal direction of the adjacent lattice that is parallel to C3' is defined as C4', the distance between C3' and C4' is defined as pitch P1'. 2 are both treated as P1 in relational formulas (1) and (2) described below, but are distinguished here for clarity. Note that P1 and P1' may be the same or different.

[0075] The pitches P1 and P1' of the gratings are 200 μm or less, preferably 100 μm or less, and more preferably 50 μm or less. By using such a grating pitch, the cathode 230 cannot be recognized visually, and therefore, when used in a direct illumination unit, a display device with excellent visibility can be obtained.

[0076] The larger the light-transmitting area (the area that transmits light without the cathode 230 or the cathode antireflection layer 220) of the direct illumination unit 200, the more efficiently the display light from the reflective display device can be transmitted. When the ratio of the area of ​​the light-transmitting area to the entire area of ​​the direct illumination unit 200 is defined as the aperture ratio, the aperture ratio is preferably 60% or more, more preferably 85% or more, and further preferably 95% or more. The width of the cathode 230 and the cathode antireflection layer 220 (the width of the cathode antireflection layer 220 is, for example, B in FIG. 2 2、 B2') and the pitch of the pattern are set so that the above conditions are satisfied.

[0077] The pattern of the island-shaped cathode 230 illustrated in FIG. 3 is a pattern in which identical rectangular islands are periodically arranged, and are arranged so as to spread out uniformly when the display unit of the display device is viewed.

[0078] The width (corresponding to W3 in FIG. 3) and the length (corresponding to W3' in FIG. 3) of the rectangular island-shaped cathode 230 are not particularly limited as long as they do not impede the effects of the disclosed technology, but are preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less.

[0079] The pitch P1 of the pattern of rectangular island-shaped cathodes 230 is the distance between the centers of gravity of adjacent islands. Specifically, in the pattern of rectangular island-shaped cathodes 230 shown in Figure 3, if the center of gravity of one island is G and the centers of gravity of adjacent rectangles are G' and G'', the distance between G and G' is the pitch P1, and the distance between G and G'' is the pitch P1'. 3 are both treated as P1 in relational expressions (1) and (2) described below, but are distinguished here for clarity. Note that P1 and P1' may be the same or different.

[0080] The island pitches P1 and P1' are each 200 μm or less, preferably 100 μm or less, and more preferably 50 μm or less. By setting the island pitch at such a level, the cathode 230 cannot be visually recognized, and therefore, when used in a direct illumination unit, a display device with excellent visibility can be obtained.

[0081] The larger the light-transmitting area (the area that transmits light without the cathode 230 or the cathode antireflection layer 220) of the direct illumination unit 200, the more efficiently the display light from the reflective display device can be transmitted. When the ratio of the area of ​​the light-transmitting area to the entire area of ​​the direct illumination unit 200 is defined as the aperture ratio, the aperture ratio is preferably 60% or more, more preferably 85% or more, and further preferably 95% or more. The width of the cathode 230 and the cathode antireflection layer 220 (the width of the cathode antireflection layer 220 is, for example, B in FIG. 3) 3、 B3') and the pitch of the pattern are set so that the above conditions are satisfied.

[0082] In the direct illumination unit 200 employing an island pattern for the cathode 230, the entire surface of the cathode 230 is covered with a transparent electrode material such as ITO or IZO, or the islands are connected to each other with patterned ITO, IZO, etc. (The cathode 230 of the display unit is covered entirely, or a cathode-connecting transparent electrode such as patterned ITO or IZO is disposed.) In this case, the ITO or IZO used to connect the islands is covered with the organic layer 240 or other insulating layer so that the cathode-connecting transparent electrode is not electrically connected to the anode 250.

[0083] <<<Reflective display device>>> The reflective display device includes, facing the viewing side, a third transparent substrate, reflective pixel electrodes arranged in a periodic pattern on the viewing side surface of the third transparent substrate, and a fourth transparent substrate opposite the third transparent substrate.

[0084] The reflective display device may be a known one such as an active or passive reflective liquid crystal display device; an EPD (electrophoretic display); or the like. A reflective display device using an active reflective liquid crystal display device includes, facing the viewing side, a TFT (thin film transistor) substrate as a third transparent substrate, a plurality of reflective pixel electrodes arranged in a periodic pattern, a display layer made of a liquid crystal layer, and a counter substrate as a fourth transparent substrate made of glass or the like arranged on the viewing side of the display layer. Hereinafter, the third transparent substrate may be referred to as the TFT substrate, and the fourth transparent substrate may be referred to as the counter substrate.

[0085] <<Third and Fourth Transparent Substrates>> The third transparent substrate is formed of a glass substrate such as borosilicate glass. In an active-drive reflective display device, TFT (thin film transistor) elements and the like are formed on the glass substrate. The fourth transparent substrate is made of glass such as borosilicate glass, and a color filter, transparent electrodes, etc. are formed on the liquid crystal layer (display layer) side of the glass substrate depending on the application and method. The fourth transparent substrate is sometimes called the opposing substrate.

[0086] <<Reflective pixel electrode>> When the reflective display device is a reflective liquid crystal display device, a reflective pixel electrode is arranged for each pixel on the TFT substrate side where the TFTs are formed. Since the pixels are arranged in a periodic pattern, the reflective pixel electrodes are also arranged in a periodic pattern. In this case, the distance between adjacent reflective pixel electrodes is defined as the pitch P2 of the reflective pixel electrode pattern. As in the example of a patterned cathode, there are multiple pairs of adjacent reflective pixel electrodes, so there may be multiple P2s (e.g., P2 and P2') just as there are P1 and P1' in the example of the cathode. Aluminum (Al) or silver (Ag) is used as a material for the reflective pixel electrodes. When the reflective display device is an EPD, the portion corresponding to the reflective pixel electrode in the reflective liquid crystal device may be a display electrode made of ITO or other metal with low reflectance.

[0087] <<Display layer>> A liquid crystal layer serving as a display layer is laminated between the TFT substrate and the counter substrate, and the transmission and blocking of light passing through the display layer can be controlled by turning on / off the applied voltage. The liquid crystal layer is not particularly limited as long as it does not impair the effects of the disclosed technology, but TN liquid crystal, STN liquid crystal, vertical alignment (VA) liquid crystal, etc. can be used. When the reflective display device is an EPD, the display layer is an EP microcapsule layer.

[0088] <<<Light scattering layer>>> The display device of the present disclosure includes a light-scattering layer, which will be described in detail below with reference to FIGS.

[0089] The light scattering layer scatters light emitted by the light-emitting layer of the organic layer in the direct illumination section and irradiates it toward the reflective pixel electrodes of the reflective display device, thereby improving the visibility of the display device and more effectively suppressing the occurrence of moire, resulting in a display device with good visibility.

[0090] In the reflective display device, the light scattering layer is laminated on the viewing side of the fourth transparent substrate 120 of the reflective display device and on the reflective display device side of the first transparent substrate of the direct illumination unit.

[0091] In Figure 5, the light scattering layer is laminated between the polarizing plate 110 and the opposing substrate 120, but the position is not limited to this and the light scattering layer may be laminated as part of the reflective display device 100, as part of the direct illumination unit 200, or may be disposed between the reflective display device 100 and the direct illumination unit 200.

[0092] The light scattering layer may be either an anisotropic light scattering layer or an isotropic light scattering layer.

[0093] Here, the anisotropic light scattering layer is a light scattering layer in which the amount of emitted light changes depending on the angle of incidence of light.

[0094] The isotropic light scattering layer is a light scattering layer in which the amount of emitted light does not change depending on the angle of incident light.

[0095] The light-scattering layer has a scattering angle θ1, which represents the angle at which light incident on the light-scattering layer is scattered as it leaves the light-scattering layer. The scattering angle θ1 is calculated by measuring the amount of diffusely transmitted light exiting the light-scattering layer when light is incident at different angles in one direction relative to the normal to the main surface of the light-scattering layer, and then calculating the diffuse transmittance. The calculated diffuse transmittance is then plotted for each incident light angle to create a graph. From this graph, the angular width between two points at half the maximum value of the diffuse transmittance (full width at half maximum, FWMH) is defined as the scattering angle θ1 (see FIG. 6; details will be described later).

[0096] As for the light scattering layer, the scattering angle θ1 is not particularly limited as long as it satisfies the relational expressions (1) and (2) described below.

[0097] Furthermore, the anisotropic light-scattering layer does not backscatter the light emitted from the direct illumination unit, thereby improving the contrast of the display device. In an isotropic light-scattering layer using typical spherical particles, incident light is refracted multiple times inside the particles, or light refracted in a direction different from the incident light angle is incident on another particle and refracted thereafter, which tends to result in light returning in the direction of the incident light angle (backscattering). On the other hand, in an anisotropic light-scattering layer, multiple columnar structures or needle-like particles are oriented within the layer, so backscattering does not occur, or if it does occur, it is relatively minimal. In particular, in a phase-separated anisotropic light-scattering layer, the refractive index changes continuously, which can further suppress backscattering.

[0098] 5 shows a cross-sectional view of the display device 1 having the stripe-type cathode 230 pattern shown in FIG. 1. The thick black arrows in the figure indicate that light E1 emitted from the light-emitting layer 242 is scattered by the light-scattering layer 300 having a scattering angle θ1, and the scattered light has a spread of 2×D1×tan(θ1 / 2). Light E2 reflected by the reflective pixel electrode is scattered again by the light-scattering layer 300 having a scattering angle θ1, and the scattered light has a spread of 2×D2×tan(θ1 / 2). Figure 5 also shows the pattern pitch P1 of the cathode 230, the pattern pitch P2 of the reflective pixel electrode 140, the shortest distance D1 from the surface of the light-scattering layer 300 on the viewing side to the surface of the reflective pixel electrode 140 on the viewing side, and the shortest distance D2 from the surface of the light-scattering layer 300 on the reflective pixel electrode 140 side to the surface of the cathode 230 on the reflective pixel electrode 140 side.

[0099] 6 is a graph showing an example of measurement results (scattering intensity curves) obtained by measuring the intensity (scattering intensity) of light emitted from the light-scattering layer 300 at different angles relative to the normal direction of the main surface of the light-scattering layer. The horizontal axis represents the angle relative to the normal direction of the main surface of the light-scattering layer 300, with the normal direction being defined as 0°. The vertical axis represents the relative value of the measured light intensity (with the maximum scattering intensity obtained by measurement being defined as 1). The angle at half-width of this scattering intensity curve is defined as the scattering angle θ1.

[0100] A display device using a light-scattering layer according to the present disclosure can more effectively suppress the occurrence of moire (periodic brightness unevenness or stripes that occur when different periodic patterns overlap) in the display of the display device by satisfying at least the following relational expressions (1) and (2): (1) P2≦2×D1×tan(θ1 / 2) (2) P1≦2×D2×tan(θ1 / 2) That is, in the display device of Patent Documents 2 and 3, when it is not "P1 = P2", which is the condition for interference fringes to occur in the display of the display device, when it is not "P1 < P2 and P1 / P2 = 1 / natural number", or when it is not "P1 > P2 and P1 / P2 = natural number", or when it is "P1 = P2", which is the condition for no interference fringes to occur in the display of the display device, when it is "P1 < P2 and P1 / P2 = 1 / natural number", or when it is "P1 > P2 and P1 / P2 = natural number", in any of these cases, a display device without interference fringes in the display unit can be obtained. Note that it is preferable to satisfy both the relational expression (1) and the relational expression (2) from the viewpoint of improving visibility.

[0101] <<Anisotropic light scattering layer>> Hereinafter, the anisotropic light scattering layer will be described in detail. The anisotropic light scattering layer has anisotropy in which the amount of emitted light changes depending on the incident light angle of light (either the polar angle, the azimuth angle, or both, hereinafter may be simply referred to as the incident light angle). In particular, the anisotropic light scattering layer has the property that the linear transmittance, which is (the amount of transmitted light in the linear direction of the incident parallel light) / (the amount of incident parallel light) × 100, changes depending on the incident light angle of light. Note that the scattering angle θ1 of the anisotropic light scattering layer can be adjusted mainly by adjusting the structural region of the anisotropic light scattering layer.

[0102] The anisotropic light scattering layer has a matrix region and a structural region provided in the matrix region, extending in the thickness direction of the matrix region, and having a different refractive index from the matrix region.

[0103] The structure of the anisotropic light scattering layer will be described. The structure of the anisotropic light scattering layer is not particularly limited as long as it does not inhibit the effects of the present disclosure technology. For example, it has a structural region with a different refractive index from the matrix region in the matrix region. Specifically, as the structural region, those in which particles are dispersed (for example, the anisotropic scattering sheet disclosed in JP-A-2006-251395, the anisotropic light scattering film disclosed in JP-A-2004-361656, etc.) and those in which a plurality of columnar structures extending in the thickness direction can be cited. An anisotropic light-scattering layer having a plurality of columnar structures as the structural region will be described below.

[0104] FIG. 7(a) is a conceptual diagram of a cross section perpendicular to the main surface of the anisotropic light-scattering layer, and FIG. 7(b) is a conceptual diagram of a cross section perpendicular to the column axes of multiple columnar structures in the anisotropic light-scattering layer. The anisotropic light-scattering layer 300 has a matrix region 310 and a plurality of columnar structures 320 provided in the matrix region 310 and having a refractive index different from that of the matrix region 310, and the plurality of columnar structures 320 are oriented and extend in the thickness direction from one surface (main surface) of the anisotropic light-scattering layer to the other surface (main surface) (see Figure 7(a)).

[0105] FIG. 7 shows a case where the aspect ratio of a plurality of pillar structures 320, which will be described later, is high. When the aspect ratio is low (for example, 1 or more and less than 2), if light parallel to the axial direction of the columnar structures is irradiated, the transmitted light is scattered isotropically. On the other hand, when the aspect ratio is high (for example, 2 or more), if light parallel to the axial direction is irradiated, the transmitted light is scattered anisotropically according to the aspect ratio.

[0106] The difference in refractive index is not particularly limited as long as the difference is such that at least a part of the parallel light incident on the anisotropic light-scattering layer is reflected at the interface between the matrix region and the plurality of columnar structures. It is known that these regions are formed when the material forming the anisotropic light-scattering layer is cured.

[0107] <Columnar structure 320> The length of the multiple columnar structures 320 in the column axis direction is not particularly limited, and may extend from one surface of the anisotropic light-scattering layer to the other surface, or may be a length that does not reach from one surface to the other surface.

[0108] The polar angle (hereinafter, this polar angle may be referred to as the columnar structure angle) formed between the normal direction (defined as 0°) of the main surface of the anisotropic light-scattering layer and the extending direction of the columnar structures 320 is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 0° to 40°, more preferably 0° to 25°, even more preferably 0° to 10°, and particularly preferably 0°. By setting the columnar structure angle in this manner, it is possible to sufficiently diffuse the light from the direct illumination unit 200.

[0109] The angle of the columnar structures can be adjusted by changing the direction of the irradiated light in the process of photocuring the uncured resin composition layer to form multiple columnar structures, thereby adjusting the axial angle of the multiple columnar structures within a desired range.

[0110] The cross section of the plurality of columnar structures perpendicular to the column axis can have a shape having a minor axis and a major axis.

[0111] The shape of the cross section perpendicular to the column axis of the plurality of columnar structures is not particularly limited and may be, for example, a circle, an ellipse, or a polygon. In the case of a circle, the minor axis and the major axis are equal, in the case of an ellipse, the minor axis is the length of the minor axis and the major axis is the length of the major axis, and in the case of a polygon, the shortest length connecting two vertices of the polygon can be the minor axis and the longest length can be the major axis.

[0112] The lower limit of the average value (average minor diameter) of the minor diameters of the plurality of columnar structures (for example, SA shown in FIG. 7(b)) is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 0.5 μm or more, more preferably 0.8 μm or more, and even more preferably 1.0 μm or more. On the other hand, the upper limit of the average minor diameter of the plurality of columnar structures is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 1.6 μm or less, more preferably 1.4 μm or less. By setting the average minor diameter in this manner, it is possible to exhibit appropriate scattering properties. The lower limit and upper limit of the average minor diameter of the plurality of columnar structures can be combined as appropriate.

[0113] The lower limit of the average value (average major axis) of the major axes of the plurality of columnar structures (for example, LA shown in FIG. 7(b)) is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 4.5 μm or more, more preferably 5.0 μm or more, and even more preferably 5.5 μm or more. On the other hand, the upper limit of the average major axis of the plurality of columnar structures is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 15.0 μm or less, more preferably 14.0 μm or less, and even more preferably 12.0 μm or less. By setting the average major axis in this manner, it is possible to increase the linear light transmittance of the anisotropic light-scattering layer. The lower and upper limits of the average major axis of the plurality of columnar structures can be combined as appropriate.

[0114] The aspect ratio of the plurality of columnar structures is calculated as the ratio of the average major axis to the average minor axis (average major axis / average minor axis). The aspect ratio of the plurality of columnar structures is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 5. By setting the aspect ratio in this manner, sufficient light scattering properties can be obtained.

[0115] The average minor axis and the average major axis of the plurality of columnar structures can be calculated as the number average values ​​of the minor axis SA and the major axis LA measured for 20 arbitrarily selected columnar structures by observing a cross section perpendicular to the column axis of the plurality of columnar structures (specifically, a cross section near the center of the thickness of the anisotropic light-scattering layer) with an optical microscope.

[0116] (scatter center axis) The anisotropic light-scattering layer has a central scattering axis, which is an axis of symmetry regarding light scattering. The central scattering axis and the orientation direction (extension direction) of the columnar structures are parallel to each other. Note that the central scattering axis and the orientation direction of the columnar structures being parallel to each other need only satisfy the law of refractive index (Snell's law), and do not necessarily have to be strictly parallel.

[0117] Snell's law states that when light is incident on the interface between a medium with a refractive index n3 and a medium with a refractive index n4, the relationship n3 sin θ3 = n4 sin θ4 holds between the incident light angle θ3 and the refraction angle θ4. For example, if n3 = 1 (refractive index of air) and n4 = 1.51 (refractive index of the anisotropic light-scattering layer), when the incident light angle is 30°, the orientation direction (refraction angle) of the structure region is approximately 19°. Even if the incident light angle and refraction angle differ in this way, as long as they satisfy Snell's law, they are included in the concept of parallel light.

[0118] The scattering central axis refers to the direction that coincides with the incident light angle of light at which the light scattering properties are approximately symmetrical across the incident light angle when the incident light angle into the anisotropic light-scattering layer is changed. The scattering central axis angle θ2, which is the incident light angle at this time, is the angle at the approximately central portion (the central portion of the diffusion region) between the minimum values ​​in an optical profile (described below) that is obtained by measuring the amount of linear transmitted light through the anisotropic light-scattering layer, calculating the linear transmittance, and plotting the linear transmittance for each incident light angle. The scattering central axis angle θ2 is also the angle (polar angle) between the normal to the anisotropic light-scattering layer and the scattering central axis.

[0119] The scattering central axis angle θ2 can be adjusted by changing the direction of the irradiated light beam in the process of photocuring the uncured resin composition layer to form multiple columnar structures, thereby adjusting the axial angle of the multiple columnar structures within a desired range.

[0120] The scattering central axis angle θ2 of the anisotropic light-scattering layer is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 0° to 40°, more preferably 0° to 25°, even more preferably 0° to 10°, and particularly preferably 0°. By setting the scattering central axis angle θ2 in this manner, it is possible to sufficiently diffuse the light from the direct illumination unit 200.

[0121] (optical profile) Fig. 8 is a graph showing an example of an optical profile of an anisotropic light-scattering layer in which the scattering central axis angle θ2 is 0°. The optical profile refers to a curve showing the incident light angle dependency of light scattering properties. As shown in Fig. 8, the anisotropic light-scattering layer has incident light angle dependency of light scattering properties, in which the linear transmittance changes depending on the incident light angle of light.

[0122] The optical profile can be created, for example, as follows. As shown in FIG. 9 , the anisotropic light-scattering layer is disposed between a light source 10 and a detector 20. In this embodiment, the incident light angle is defined as 0° when the irradiated light I from the light source 10 is incident from the normal direction of the main surface of the anisotropic light-scattering layer. The anisotropic light-scattering layer is disposed so that it can be rotated arbitrarily around a line V as the rotation axis, while the light source 10 and the detector 20 are fixed. That is, according to this method, a sample (anisotropic light-scattering layer) is disposed between the light source 10 and the detector 20, and the amount of linear transmitted light that passes through the sample and enters the detector 20 is measured while changing the angle around the line V on the sample surface as the rotation axis. The line V is defined as an orientation perpendicular to the tilt orientation of the light irradiation angle during the manufacture of the anisotropic light-scattering layer (in other words, an orientation perpendicular to the tilt orientation of the structural region of the anisotropic light-scattering layer). The linear transmittance is then calculated from the amount of linear transmitted light, and this linear transmittance is plotted for each angle to create an optical profile. This evaluation method makes it possible to evaluate the range of angles at which incident light is mainly scattered.

[0123] Although the optical profile does not directly express light scattering (or light diffusion), if we interpret it as meaning that a decrease in linear transmittance results in an increase in scattered transmittance, it can be said that it generally indicates light scattering.

[0124] A typical isotropic light scattering layer exhibits a mountain-shaped optical profile that peaks at an incident light angle of approximately 0°. In contrast, for example, the optical profile graph of an anisotropic light-scattering layer in which the scattering central axis angle θ2 is 0° in Figure 8 shows a valley-shaped optical profile in which the linear transmittance is small at incident light angles around 0° (-20° to +20°), and the linear transmittance increases as the absolute value of the incident light angle increases.

[0125] Thus, the anisotropic light-scattering layer has the property that incident light is strongly scattered in the incident light angle range close to the scattering central axis, but scattering weakens and the linear transmittance increases in a larger incident light angle range.

[0126] (Linear transmittance) As described above, the anisotropic light-scattering layer has a property that the linear transmittance, which is (amount of transmitted light in the linear direction of incident light) / (amount of incident light) × 100, changes depending on the angle of incident light, and the linear transmittance in the present invention is obtained by measuring the amount of linear transmitted light when creating an optical profile.

[0127] (Linear transmittance at an incident light angle of 0°) The upper limit of the linear transmittance of the anisotropic light-scattering layer at an incident light angle of 0° is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 40% or less, 25% or less, 10% or less, or 5% or less. By setting the linear transmittance at an incident light angle of 0° in this manner, the occurrence of moire can be more effectively suppressed and visibility can be improved.

[0128] (Maximum linear transmittance) As shown in FIG. 8, the linear transmittance of light incident on the anisotropic light-scattering layer at an incident light angle at which the linear transmittance is maximized is referred to as the maximum linear transmittance. The maximum linear transmittance of the anisotropic light-scattering layer is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 60% or less. By setting the maximum linear transmittance in this manner, the occurrence of moire can be more effectively suppressed and visibility can be improved.

[0129] (Minimum linear transmittance) As shown in FIG. 8, the linear transmittance of light incident on the anisotropic light-scattering layer at an incident light angle at which the linear transmittance is minimum is referred to as the minimum linear transmittance. The minimum linear transmittance of the anisotropic light-scattering layer is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 10% or less. By setting the minimum linear transmittance in this manner, the occurrence of moire can be more effectively suppressed and visibility can be improved.

[0130] (diffusion region, non-diffusion region) Furthermore, as shown in Figure 8, the angular range of two incident light angles for a linear transmittance intermediate between the maximum linear transmittance and the minimum linear transmittance is called the diffusion region (the width of this diffusion region is the "diffusion width"), and the incident light angle range excluding this is called the non-diffusion region (transmission region).

[0131] The linear transmittance can be adjusted by the refractive index of the material of the anisotropic light-scattering layer (the difference in refractive index when multiple resins are used), the thickness of the coating film, and curing conditions such as UV irradiance and temperature during structure formation.

[0132] (Haze value) The haze value (total haze) of the anisotropic light-scattering layer is an index showing the scattering properties of the anisotropic light-scattering layer. As the haze value increases, the scattering properties of the anisotropic light-scattering layer increase. The method for measuring the haze value is not particularly limited, and can be measured by a known method, for example, according to JIS K7136:2000 "Method for determining haze of plastics - transparent materials."

[0133] The lower limit of the haze value of the anisotropic light-scattering layer is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 40% or more, more preferably 60% or more, and even more preferably 80% or more.

[0134] The haze value of the anisotropic light-scattering layer can be adjusted by the refractive index of the material of the anisotropic light-scattering layer (the difference in refractive index if multiple resins are used), the thickness of the coating film, and curing conditions such as UV irradiance and temperature during structure formation.

[0135] (Thickness) The thickness of the anisotropic light-scattering layer is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 10 μm to 200 μm, more preferably 15 μm to 150 μm, and even more preferably 20 μm to 100 μm. By setting the thickness in this manner, it becomes easier to simultaneously suppress the occurrence of moire due to light diffusion and reduce image blur (improvement of visibility) by reducing the thickness. Note that the thickness of the anisotropic light-scattering layer in the present invention is the number average of values ​​measured at a total of five locations, including four locations near the four corners and one location near the center, on the main surface of the anisotropic light-scattering layer.

[0136] <Method for manufacturing anisotropic light-scattering layer> The anisotropic light-scattering layer can be manufactured according to a known method, and the manufacturing method is not particularly limited. The anisotropic light-scattering layer can be manufactured by referring to the methods and raw materials described in, for example, JP 2021-162733 A, JP 2006-119241 A, and International Publication No. WO2014 / 084361.

[0137] As a process for forming an anisotropic light-scattering layer, the following process is disclosed as a known method. Step 1-1: Step of Providing an Uncured Resin Composition Layer on a Substrate Step 1-2: Obtaining parallel light from a light source or using linear light as a light source Step 1-3 (optional step): A step of directing parallel light rays into a directional diffusion element to obtain directional light rays. Step 1-4: A step of irradiating the uncured resin composition layer with light to cure the uncured resin composition layer

[0138] In step 1-3, the shape (aspect ratio, minor axis SA, major axis LA, etc.) of the plurality of columnar structures in the anisotropic light-scattering layer can be adjusted by adjusting the spread of directional light, etc.

[0139] In step 1-4, the angle of the plurality of columnar structures and the scattering central axis angle θ2 of the anisotropic light-scattering layer can be adjusted by adjusting the angle at which light rays are incident on the uncured resin composition layer.

[0140] <<Isotropic light scattering layer>> Examples of the isotropic light-scattering layer include those whose surfaces are processed into an uneven or dotted shape, and those in which particles are dispersed in the layer. The scattering angle θ1 of the isotropic light-scattering layer can be adjusted by changing the thickness of the isotropic light-scattering layer, the size and distribution of the surface shape, and the size, distribution, density, and reflection characteristics of the reflective particles.

[0141] <<<<<Examples of Implementation>>>> Below, specific examples of embodiments relating to the display device of the present disclosure will be described, but the display device of the present disclosure is not limited to these. In the following explanation, the display device of Fig. 5 will be described in detail as Example 1 of Embodiment, and the display devices of Figs. 10 to 15, which are Example 2 to Example 5 of Embodiment, will be described mainly focusing on the differences from Example 1 of Embodiment. Therefore, the explanations for parts not provided in Figs. 10 to 15 are the same as the explanations for the corresponding parts in Fig. 5.

[0142] <<<Embodiment Example 1>>> A first embodiment of the display device of the present disclosure will be described with reference to Fig. 5. Fig. 5 is a cross-sectional view of the display device shown in Fig. 1 taken along the line AA. As shown in Fig. 5, the first embodiment includes a reflective display device 100 having a display unit, a light-scattering layer 300 contained in the reflective display device 100, and a direct illumination unit 200 disposed on the viewing side of the display unit of the reflective display device 100 and irradiating light onto the reflective display device 100. Fig. 5 shows an example in which a reflective liquid crystal display device is used as the reflective display device 100.

[0143] The direct illumination unit 200 is disposed so that the first transparent substrate 260 side of the direct illumination unit 200 faces the display unit of the reflective display device 100. The direct illumination unit 200 is preferably disposed close to the reflective display device 100.

[0144] If an air layer exists between the direct illumination unit 200 and the reflective display device 100, when light emitted from the first transparent substrate 260 enters the air layer, it is reflected by the surface of the first transparent substrate 260 facing the reflective display device 100 and returns to the viewer, thereby reducing the contrast of the display unit of the display device 1. Therefore, it is preferable to eliminate the air layer by laminating a resin layer or the like having the same refractive index as the first transparent substrate 260 between the direct illumination unit 200 and the reflective display device 100. In FIG. 5, a second resin layer 261 is laminated between the first transparent substrate 260 and the polarizing plate 110 of the reflective display device 100.

[0145] The direct-type illumination unit 200 is an organic electroluminescence element including a first transparent substrate 260, a second transparent substrate 210 facing the first transparent substrate 260, an anode 250 stacked on the viewing side of the first transparent substrate 260, an organic layer 240 stacked on the viewing side of the anode 250, and a cathode 230 stacked on the viewing side of the organic layer 240 and arranged in a periodic pattern. The direct-type illumination unit 200 in FIG. 5 also includes a first thin-film sealing layer 270 formed to cover a portion corresponding to the display surface, and a cathode antireflection layer 220 covering the viewing-side surface of the cathode 230 via the first thin-film sealing layer 270. Also, in FIG. 5, the organic layer 240 is illustrated as being composed of an electron transport layer 241, a light-emitting layer 242, and a hole transport layer 243.

[0146] The reflective display device 100 includes a TFT substrate 150 provided on the display unit side of the reflective display device 100, a counter substrate 120 arranged to face the TFT substrate 150, a display layer 130 made of a liquid crystal layer provided between the TFT substrate 150 and the counter substrate 120, and reflective pixel electrodes 140 arranged in a periodic pattern on the viewing side surface of the TFT substrate 150. The counter substrate 120 is provided with a counter electrode (not shown).

[0147] 5, the light-scattering layer 300 is laminated between the polarizing plate 110 and the counter substrate 120, but the position is not limited to this, and in the display device 1, the light-scattering layer 300 is laminated on the viewing side of the liquid crystal layer 130 and on the reflective display device 100 side of the anode 250 of the direct illumination unit 200. The light-scattering layer 300 may be laminated as part of the reflective display device 100, may be laminated as part of the direct illumination unit 200, or may be disposed between the reflective display device 100 and the direct illumination unit 200.

[0148] In the display device 1, when the pattern pitch of the cathode 230 is P1, the pitch between the patterns of the reflective pixel electrodes 140 is P2, the distance from the viewing side surface of the light scattering layer 300 to the viewing side surface of the reflective pixel electrode 140 is D1, the shortest distance from the surface of the light scattering layer 300 facing the reflective pixel electrode 140 to the surface of the cathode 230 facing the reflective pixel electrode 140 is D2, and the scattering angle of the light scattering layer 300 is θ1, the relationship between the light scattering layer 300 and the reflective pixel electrode 140 is expressed by the following equations (1) and (2). (1) P2≦2×D1×tan(θ1 / 2) (2) P1≦2×D2×tan(θ1 / 2)

[0149] The operation of the display device 1 described above will be described with reference to FIG. 5 . When a voltage is applied between the cathode 230 and the anode 250 of the direct illumination unit 200, electrons are injected from the cathode 230 into the electron transport layer 241. At the same time, holes (positive holes) are injected from the anode 250 into the hole transport layer 243. At this time, electrons are generated on the anode 250 side of the cathode 230, and hole injection occurs only on the surface of the anode 250 on the viewer side when the cathode 230 is orthogonally projected onto the anode 250 along the z axis. The electrons injected into the electron transport layer 241 are transported in the direction opposite to the z direction within the region of the electron transport layer 241 sandwiched between the cathode 230 and the anode 250, and reach the light-emitting layer 242. The holes injected into the hole transport layer 243 are transported in the z direction within the region of the hole transport layer 243 sandwiched between the cathode 230 and the anode 250, and reach the light-emitting layer 242. The electrons and holes that reach the light-emitting layer 242 recombine in the region between the cathode 230 and the anode 250 in the light-emitting layer 242, exciting the light-emitting material of the light-emitting layer 242. The excited light-emitting material emits light from the light-emitting layer 242 in the z direction and in the direction opposite to the z direction. The light emitted in the z direction is reflected by the cathode 230 toward the reflective display device. Therefore, it does not reach the eyes of a viewer on the viewing side of the display device. The light E1 emitted in the direction opposite to the z direction is polarized by the polarizer 110, scattered by the light-scattering layer 300, passes through the counter substrate 120 and the liquid crystal layer 130, and reaches the reflective pixel electrode 140. The reflective pixel electrode 140 reflects the light E1 that reaches it toward the viewing side. Light E2 reflected by the reflective pixel electrode 140 passes through the liquid crystal layer 130 and the counter substrate 120, is scattered by the light-scattering layer 300, is polarized by the polarizer 110, and passes through the direct-type illumination unit 200 to enter the viewer's eye. When the light E2 reflected by the reflective pixel electrode 140 passes through the gap between adjacent cathode antireflection layers 220, the light E2 passes through the direct-type illumination unit 200. When an isotropic light-scattering layer is used as the light-scattering layer 300, and at least the relationship between P1 and the pitch P2 of the reflective pixel electrodes 140 is satisfied, the display device 1 can more effectively suppress the occurrence of moiré, resulting in a display device with superior visibility. Therefore, by adjusting θ1, the occurrence of moiré can be more effectively suppressed even when P1, P2, and D2 are arbitrarily set, thereby increasing the design flexibility of the display device 1. From the above, the display device of the present disclosure does not generate interference fringes even when "P1 = P2", which is said to cause interference fringes in the display devices disclosed in Patent Documents 2 and 3, or when "one of P1 and P2 is not a natural number multiple of the other". It should be noted that when considering the relationship between P1 and P2 in the case where there are multiple P1 and P2 (for example, when the pattern of the cathode 230 and the pattern of the reflective pixel electrode 140 are not similar in shape), as will be described later, the relational expression is considered for P1 and P2 that are in the same plane. For example, in the case of FIG. 5, the relationship between P1 and P2 that exist in the cross section of the display device shown in FIG. 5 is considered. When P1 and P2 are not in the same plane, it is considered that the case where "one of P1 and P2 is not a natural number multiple of the other" holds.

[0150] The direct-type illumination unit 200 is an electroluminescence element that includes a first transparent substrate 260, a second transparent substrate 210 facing the first transparent substrate 260, an anode 250 laminated on the viewing side of the first transparent substrate 260, an organic layer 240 laminated on the viewing side of the anode 250, and a cathode 230 arranged in a periodic pattern on the viewing side of the organic layer 240. The direct-type illumination unit 200 is disposed in the display device 1 with the first transparent substrate 260 side facing the display unit of the reflective display device 100. An anti-reflection layer 280 is laminated on the outermost surface on the viewing side of the direct-type illumination unit 200 to prevent reflection of external light.

[0151] An anode 250 is laminated directly or via another layer on the viewing side (second transparent substrate 210 side) of the first transparent substrate 260. The anode 250 may be formed as a periodic pattern at a position corresponding to the cathode 230 arranged in a periodic pattern (a position on the xy plane on the viewing side surface of the first transparent substrate 260 corresponding to a position on the xy plane on the surface on which the cathode 230 is laminated), or may be formed as a layer so as to cover the entire surface of the first transparent substrate 260.

[0152] The organic layer 240 can be laminated directly on the viewing side (cathode 230 side) of the anode 250, or via other layers such as a hole injection layer, a transparent protective layer, etc. The organic layer 240 and other layers such as the hole injection layer and the transparent protective layer may form a periodic pattern similar to the anode 250, or may be formed as a substantially uniform layer so as to cover the entire surface of the anode 250.

[0153] The organic layer 240 has a three-layer structure in which a hole transport layer 243, a light-emitting layer 242, and an electron transport layer 241 are stacked in this order from the anode 250 side. The organic layer 240 may include other layers such as an electron injection layer as necessary.

[0154] The light-emitting layer 242 contains a light-emitting material, and when a voltage is applied between the anode 250 and the cathode 230, holes and electrons injected from each electrode recombine in the light-emitting layer 242, causing the light-emitting material to enter an excited state. The light emitted from the excited light-emitting material is released to the outside, causing the organic electroluminescence element to emit light.

[0155] The hole transport layer 243 is used to efficiently transport holes injected from the anode 250 toward the light emitting layer 242 .

[0156] The electron transport layer 241 is used to efficiently transport electrons injected from the cathode 230 toward the light-emitting layer 242 .

[0157] The cathode 230 is disposed in a periodic pattern on the viewing side surface of the organic layer 240. The cathode 230 is formed so as to be laminated on the surface of the organic layer 240.

[0158] The periodic pattern of the cathode 230 is formed with a constant pitch. The shape of the pattern of the cathode 230 observed from the viewing side is not particularly limited as long as it does not impair the effects of the disclosed technology, and examples thereof include a stripe type shown in FIG. 1, a grid type shown in FIG. 2, and an island type shown in FIG. 3. FIGS. 1 to 3 show top views of the display units of a display device 1, a display device 1′, and a display device 1″, respectively, when observed from the viewing side. (Hereinafter, when the term “display device 1” is used without any specific notice, it can be read as “display device 1′” or “display device 1″”). FIGS. 1 to 3 illustrate the pattern shapes of the cathode antireflection layer 220 indicated by diagonal lines and the cathode 230 present on the depth side of the cathode antireflection layer 220 in the drawings. When a voltage is applied to the cathode 230 and the anode 250, a part of the light-emitting layer 242 sandwiched between the cathode 230 and the anode 250 directly below it (the anode 250 existing on the same z-axis as the cathode 230, see FIG. 5) emits light. Therefore, when viewing the display device 1 from the viewing side, the part where the cathode 230 exists is the part that emits light (hereinafter referred to as the light-emitting region), and the part where the cathode 230 does not exist is the part that does not emit light (hereinafter referred to as the non-light-emitting region).

[0159] The direct illumination unit 200 can cover the viewer-side surface of the cathode 230 with a cathode antireflection layer 220. The cathode antireflection layer 220 is used to prevent external light from being reflected by the cathode. The cathode antireflection layer 220 prevents external light from being reflected from the cathode surface to the viewer, thereby increasing the contrast of the display device 1. For this reason, the cathode antireflection layer 220 may be patterned similarly to the cathode 230 as shown in FIGS. 1 to 3, or may be larger than the cathode 230. The cathode antireflection layer 220 is produced by applying a black pigment resist, which is a photoresist resin material containing a black pigment such as graphite, or a black dye resist, which is a photoresist resin material containing a black dye, onto the first thin-film encapsulating layer 270 by spin coating or the like, and then forming a required pattern by exposure and development processes. The cathode antireflection layer 220 can also be formed from an inorganic film such as a chromium oxide layer. For example, after forming a chromium oxide film by sputtering, a required pattern is formed by a series of photolithography processes including resist application, exposure, development, etching of the chromium oxide, and resist removal. The thickness of such a light-reflecting layer or light-absorbing layer is preferably 1 to 50 μm, more preferably 1 to 5 μm, when a black pigment resist or black dye resist is used, and is preferably 100 to 5000 nm, more preferably 100 to 500 nm, when an inorganic film such as chromium oxide is used. By forming the layer as thin as possible within the range that allows anti-reflection, the dimensional accuracy of patterning can be improved.

[0160] The reflective display device 100 includes a TFT substrate 150 provided on the display side of the reflective display device 100, a counter substrate 120 arranged opposite the TFT substrate 150, a display layer 130 (here, the display layer 130 is a liquid crystal layer) provided between the TFT substrate 150 and the counter substrate 120, a reflective pixel electrode 140 arranged in a periodic pattern on the viewing side surface of the TFT substrate 150, and a polarizing plate 110 laminated on the viewing side of the counter substrate 120.

[0161] The TFT substrate 150 is a transparent substrate, and thin film transistors (TFTs) (not shown) for switching each pixel are formed on the visible side of the TFT substrate 150. The TFTs are covered with an interlayer insulating film (not shown), and reflective pixel electrodes 140 made of a reflective material are formed on the interlayer insulating film as pixel electrodes corresponding to each TFT. The reflective pixel electrodes 140 are connected to the drain or source of the corresponding TFT through contact holes (not shown) formed in the interlayer insulating film.

[0162] The reflective pixel electrode 140 is arranged for each pixel, and although not shown, each pixel may adopt, for example, a stripe arrangement or a mosaic arrangement.

[0163] The counter substrate 120 is a transparent substrate, and a transparent electrode (not shown) is formed on its surface (on the TFT substrate 150 side).

[0164] A display layer 130 (here, the display layer 130 is a liquid crystal layer) is laminated between the TFT substrate 150 and the opposing substrate 120, and the orientation of the liquid crystal in the display layer 130 (here, the display layer 130 is a liquid crystal layer) is controlled by adjusting the voltage applied between the transparent electrode and the reflective pixel electrode 140.

[0165] The polarizing plate 110 is laminated on the viewing side of the counter substrate 120 .

[0166] The light-scattering layer 300 scatters the light emitted from the light-emitting layer 242 of the organic electroluminescence element and uniformly irradiates the light onto the reflective pixel electrodes 140 of the reflective display device 100, thereby improving the visibility of the display device 1. Furthermore, by adjusting the scattering angle θ1 of the light-scattering layer 300, the occurrence of moire can be efficiently suppressed, resulting in a display device 1 with better visibility.

[0167] The light scattering layer 300 is laminated on the viewing side of the display layer 130 of the reflective display device 100 (here, the display layer 130 is a liquid crystal layer) and on the reflective display device 100 side of the anode 250 of the direct illumination unit 200.

[0168] The light-scattering layer 300 may be either an isotropic light-scattering layer or an anisotropic light-scattering layer. The light-scattering layer 300 has a scattering angle θ1, which satisfies the relational expressions (1) and (2). From the viewpoint of not scattering back the light irradiated from the direct illumination unit 200 and improving the contrast of the display device 1, an anisotropic light-scattering layer is preferred. The thickness of the first transparent substrate is preferably 0.6 mm or less, more preferably 0.3 mm or less. This allows the direct-view illumination unit to be thinner and lighter, making the entire display device lighter, thinner, shorter, and smaller. It also allows light emitted from the organic layer to efficiently reach the reflective display. To make the thickness of the glass substrate 0.3 mm or less, after the direct-view illumination unit is assembled (with both surfaces made of glass), the glass substrate is thinned by glass etching, glass polishing, or the like. The distance between the light-emitting layer 242 and the reflective pixel electrode 140 is preferably 1.4 mm or less, and more preferably 1.0 mm or less. This allows the thickness and weight of the direct-view illumination unit to be reduced, making the entire display device lighter, thinner, shorter, and smaller. Furthermore, the light emitted from the organic layer can be efficiently transmitted to the reflective display. In this case, the light-scattering layer 300 may be either an anisotropic scattering layer or an isotropic scattering layer, or may be omitted.

[0169] <<<Embodiment Example 2>>> 10, the second embodiment includes a reflective display device 100 having a display unit (not shown), a light scattering layer 300, a direct illumination unit 200 that is arranged on the viewing side of the display unit of the reflective display device 100 and irradiates the reflective display device 100 with light, and a cathode anti-reflection polarizer 290 that prevents reflection from the cathode 230 of the direct illumination unit 200. Note that this example shows a reflective liquid crystal device as the reflective display device 100.

[0170] The direct illumination unit 200 is disposed so that the first transparent substrate 260 side of the direct illumination unit 200 faces the display unit of the reflective display device 100 .

[0171] In order to eliminate the air gap between the direct illumination unit 200 and the reflective display device 100, a second resin layer 261 is laminated between the first transparent substrate 260 and the polarizing plate 110 of the reflective display device 100.

[0172] The direct-type illumination unit 200 is an organic electroluminescence element including a first transparent substrate 260, a second transparent substrate 210 facing the first transparent substrate 260, an anode 250 laminated on the viewing side of the first transparent substrate 260, an organic layer 240 laminated on the viewing side of the anode 250, and a cathode 230 laminated on the viewing side of the organic layer 240 and arranged in a periodic pattern. A first thin-film sealing layer 270 is formed on the viewing side of the cathode 230 so as to cover the portion corresponding to the display surface, and the second transparent substrate 210 is further disposed via a first resin layer 211. The first thin-film sealing layer 270 and the second transparent substrate 210 are bonded together with an acrylic adhesive. A cathode anti-reflection polarizer 290 is disposed on the viewing side of the second transparent substrate 210 as a means for preventing reflection from the cathode 230 of the direct-type illumination unit 200. An anti-reflection layer 280 is laminated on the outermost surface on the viewing side of the direct illumination unit 200 to prevent reflection of external light.

[0173] The reflective display device 100 comprises a TFT substrate 150 provided on the display side of the reflective display device 100, a counter substrate 120 arranged opposite the TFT substrate 150, a display layer 130 (here, the display layer 130 is a liquid crystal layer) provided between the TFT substrate 150 and the counter substrate 120, reflective pixel electrodes 140 arranged in a periodic pattern on the viewing side surface of the TFT substrate 150, and an optical compensation film (not shown) and a polarizing plate laminated on the viewing side of the counter substrate 120.

[0174] The light scattering layer 300 is laminated between the polarizing plate 110 and the opposing substrate 120, but is not limited to this position, and may be laminated on the viewing side of the liquid crystal layer 130 and on the reflective display device 100 side of the anode 250 of the direct illumination section 200.

[0175] In the second embodiment, the cathode antireflection layer 220 is not formed, and a cathode antireflection polarizing plate 290 is disposed on the viewing side of the second transparent substrate 210. The cathode antireflection polarizing plate 290 is not particularly limited as long as it does not impair the effects of the disclosed technology, and any known polarizing plate can be used. The single transmittance (light transmittance of a single polarizing plate) of the cathode anti-reflection polarizing plate 290 is not particularly limited as long as it does not impair the effects of the disclosed technology, but is preferably 40% or more, more preferably 43% or more, and even more preferably 45% or more. The cathode anti-reflection polarizing plate 290 is arranged so that the light transmission axis thereof is preferably within ±5°, more preferably within ±1°, of parallel to the light transmission axis of the polarizing plate 110 of the reflective display device 100. This arrangement makes it possible to more efficiently cut reflected light from the cathode 230 and to sufficiently transmit light from the reflective display device 100. In the second embodiment, the formation of the cathode antireflection layer 220 is omitted, thereby simplifying the manufacturing process of the direct illumination unit 200 and preventing reflection of external light from the cathode 230 .

[0176] <<<Embodiment Example 3>>> A third embodiment will be described with reference to Figures 11 to 13. As shown in Figure 12, the third embodiment includes a reflective display device 100 having a display unit (not shown), a light-scattering layer 300, and a direct illumination unit 200 that is arranged on the viewing side of the display unit of the reflective display device 100 and irradiates the reflective display device 100 with light, and the anode 250 of the direct illumination unit 200 is patterned periodically, and an anode-connecting electrode 251 is formed to prevent a voltage drop in the patterned anode 250. Note that this example shows a reflective liquid crystal display device as the reflective display device 100.

[0177] The direct illumination unit 200 is disposed so that the first transparent substrate 260 side of the direct illumination unit 200 faces the display unit of the reflective display device 100 .

[0178] The anode 250 uses a material with a higher refractive index than other layers, such as ITO or IZO, and periodic patterning of the anode 250 is effective in preventing reflection at the interface of the anode 250 and improving visibility. However, ITO and IZO have relatively high electrical resistance, and when a pattern is formed, voltage drop, in which the applied voltage decreases, becomes an issue. In the third embodiment, this issue is resolved by providing an anode-connecting electrode 251.

[0179] FIG. 11 is a view of the anode 250, cathode 230, and anode connecting electrode 251 of the third embodiment, as viewed from the viewing side. FIG. 11(b) illustrates the anode 250 and the anode connecting electrode 251, with adjacent striped anodes 250 connected by the anode connecting electrode 251. As shown in FIG. 11(b), the anode 250 has a slightly wider width at the portion that contacts the anode connecting electrode 251 compared to other portions, facilitating contact. Connecting adjacent striped anodes 250 by the anode connecting electrode 251, which is made of the same material as the cathode 230, such as Al, which has low electrical resistance, makes it possible to apply a sufficient voltage to the anode 250 and prevents voltage drop. The larger the display screen, the greater this effect becomes.

[0180] 12 is a cross-sectional view of the display device 1b taken along the FF cross section of FIG. 11. The direct-illumination unit 200 includes, from the viewing side, a first transparent substrate 260, anodes 250 arranged in a periodic striped pattern, an organic layer 240, and cathodes 230 arranged in a periodic striped pattern. Adjacent anodes 250 in the striped pattern are connected by an anode-connecting electrode 251. Furthermore, a first thin-film sealing layer 270 is formed on the viewing side of the cathodes 230, the organic layer 240, the anodes 250, and the anode-connecting electrode 251. A cathode antireflection layer 220 is laminated on the viewing side of the first thin-film sealing layer 270 so as to cover the cathodes 230 and the anode-connecting electrode 251. A second transparent substrate 210 is laminated on the viewing side via a first resin layer 211. An antireflection layer 280 is laminated on the viewing side of the second transparent substrate 210. The organic layer 240 may be formed to cover the entire display surface, but it is preferable to form it in a pattern to efficiently transmit light from the reflective display device. When the organic layer 240 is patterned, it is formed so that it is wider than the cathode 230 to prevent contact between the cathode 230 and the anode 250. Fig. 11(a) shows a pattern of the simultaneously formed cathode 230 and anode-connecting electrode 251 as viewed from the viewing side, and Fig. 11(c) shows a pattern of the cathode antireflection layer 220 as viewed from the viewing side. Fig. 13 is an E-E cross-sectional view of the third embodiment in Fig. 11.

[0181] The anode 250, organic layer 240, and cathode 230 are formed on the first transparent substrate 260 by vapor deposition using a metal mask, but the anode-connecting electrode 251 is formed using a metal mask with a predetermined pattern at the same time as the formation of the cathode 230. Therefore, the anode-connecting electrode 251 is made of the same material as the cathode 230, and has approximately the same thickness. Compared with ITO or IZO, which are the materials of the anode 250, Al and the like used for the cathode 230 have low electrical resistance, and therefore the anode-connecting electrode 251 can prevent a voltage drop in the voltage applied to the anode 250. This reduces the power consumption of the lighting device, and this effect becomes more pronounced the larger the area of ​​the lighting device. The cathode 230 and the anode-connecting electrode 251 are preferably thicker to reduce voltage drop, but if they are too thick, distortion of the shape occurs and material costs rise. For these reasons, the thickness is preferably 10 nm to 1000 nm, and more preferably 30 nm to 500 nm.

[0182] The reflective display device 100 comprises a TFT substrate 150 provided on the display side of the reflective display device 100, a counter substrate 120 arranged opposite the TFT substrate 150, a display layer 130 (here, the display layer 130 is a liquid crystal layer) provided between the TFT substrate 150 and the counter substrate 120, reflective pixel electrodes 140 arranged in a periodic pattern on the viewing side surface of the TFT substrate 150, and an optical compensation film (not shown) and a polarizing plate laminated on the viewing side of the counter substrate 120.

[0183] The light-scattering layer 300 is formed between the reflective display device 100 and the direct illumination unit 200. The light-scattering layer 300 is bonded to the first transparent substrate 260 via a second resin layer 261. Although not shown, a resin layer is also formed between the light-scattering layer 300 and the polarizing plate 110 to prevent the formation of an air layer.

[0184] <<<Embodiment Example 4>>> A fourth embodiment will be described with reference to Fig. 14. As shown in Fig. 14, the fourth embodiment includes a reflective display device 100 having a display unit (not shown), a light scattering layer 300, and a direct illumination unit 200 that is arranged on the viewing side of the display unit of the reflective display device 100 and irradiates the reflective display device 100 with light, and the direct illumination unit 200 uses a first transparent resin substrate 265 and a second transparent resin substrate 215. An example is shown in which a reflective liquid crystal display device is used as the reflective display device 100.

[0185] The direct illumination unit 200 is disposed so that the first transparent resin substrate 265 of the direct illumination unit 200 faces the display unit of the reflective display device 100 .

[0186] In the fourth embodiment, a resin substrate is used for the direct illumination unit 200, thereby realizing a light and thin direct illumination unit 200 and a thin and lightweight display device 1c. In addition, the resin substrate allows for easy adjustment of the refractive index, which can improve the efficiency of light utilization from the organic layer.

[0187] The direct-type illumination unit 200 in the fourth embodiment is an organic electroluminescence element including a first transparent resin substrate 265, a second transparent resin substrate 215 facing the first transparent resin substrate 265, a second thin-film sealing layer 271 laminated on the viewing side of the first transparent resin substrate 265, an anode 250 arranged on the viewing side of the second thin-film sealing layer 271 to form a periodic pattern, an organic layer 240 laminated on the viewing side of the anode 250, a cathode 230 arranged on the viewing side of the organic layer 240 to form a periodic pattern, and an anode connecting electrode 251 connecting adjacent anodes 250 to each other. Furthermore, a first thin-film sealing layer 270 is formed on the viewing side of the cathode 230, the organic layer 240, the anode 250, and the anode-connecting electrode 251, and a cathode antireflection layer 220 is laminated on the viewing side of the first thin-film sealing layer 270 so as to cover the cathode 230 and the anode-connecting electrode 251, and a second transparent resin substrate 215 is laminated via a first resin layer 211. An antireflection layer 280 is laminated on the viewing side of the second transparent resin substrate 215.

[0188] The shapes of the anode 250, the cathode 230, the anode-connecting electrode 251, and the cathode antireflection layer 220 in the fourth embodiment as viewed from the viewing side are the same as those shown in FIG. 11, and the shapes of the anode 250, the cathode 230, the anode-connecting electrode 251, and the cathode antireflection layer 220 in FIG. 14 are the same as the structure of the FF cross section in FIG. 11. The organic layer 240 may be formed to cover the entire display surface, but it is preferable to form it in a pattern in order to efficiently transmit light from the reflective display device. When the organic layer 240 is patterned, it is formed so that it is wider than the cathode 230, thereby preventing contact between the cathode 230 and the anode 250.

[0189] The first transparent resin substrate and the second transparent resin substrate will be described with reference to FIG. In the fourth embodiment, a highly heat-resistant polyimide is used for the first transparent resin substrate 265. This is because high temperatures are required to form the anode 250, the organic layer 240, the cathode 230, and the like. A second thin-film sealing layer 271 is formed on the viewing side of the first transparent resin substrate 265 to prevent impurities such as moisture from entering the anode 250, the organic layer 240, and the cathode 230. Although polyimide is used for the second transparent resin substrate 215, the second transparent resin substrate 215 may have lower heat resistance than the first transparent resin substrate 265 because it is laminated after the anode 250, the organic layer 240, the cathode 230, and the like are formed.

[0190] The direct illumination unit 200 using the first transparent resin substrate 265 and the second transparent resin substrate 215 is manufactured as follows. A polyimide film (first transparent resin substrate 265) is formed on the glass substrate by applying a UV release agent (a resin whose adhesive strength decreases when exposed to UV light) and polyimide resin using a spin coater or similar device and drying the applied material. A second thin-film encapsulating layer 271 (SiO2) is then formed on the formed polyimide film (first transparent resin substrate 265) using a sputtering device. Furthermore, ITO (anode 250), organic layer 240, aluminum (cathode 230, anode connection electrode 251), and first thin-film encapsulating layer 270 are successively formed by vapor deposition using a metal mask. A vapor deposition device manufactured by Tokki Corporation or similar can be used for this successive vapor deposition formation. A black resist is then applied using a spin coater or similar device, followed by exposure and development processes to form a cathode antireflection layer 220. A PET film with an antireflection layer formed thereon is then attached via the first resin layer 211 to form a second transparent resin substrate 215 and an antireflection layer 280. In this state, the polyimide film (first transparent resin substrate 265) remains formed on the glass substrate, but finally, an ultraviolet irradiation device is used to peel off the glass substrate from the polyimide film (first transparent resin substrate 265), completing the direct-type illumination unit 200 using the first transparent resin substrate 265 and the second transparent resin substrate 215.

[0191] The reflective display device 100 comprises a TFT substrate 150 provided on the display side of the reflective display device 100, a counter substrate 120 arranged opposite the TFT substrate 150, a display layer 130 (here, the display layer 130 is a liquid crystal layer) provided between the TFT substrate 150 and the counter substrate 120, reflective pixel electrodes 140 arranged in a periodic pattern on the viewing side surface of the TFT substrate 150, and an optical compensation film (not shown) and a polarizing plate laminated on the viewing side of the counter substrate 120.

[0192] The light-scattering layer 300 is formed between the reflective display device 100 and the direct illumination unit 200. The light-scattering layer 300 is bonded to the first transparent substrate 260 via a second resin layer 261. Although not shown, a resin layer is also formed between the light-scattering layer 300 and the polarizing plate 110 to prevent the formation of an air layer.

[0193] <<<Embodiment Example 5>>> A fifth embodiment will be described with reference to Fig. 15. As shown in Fig. 15, the fifth embodiment includes a reflective display device 100 having a display unit (not shown), a light scattering layer 300, and a direct illumination unit 200 that is arranged on the viewing side of the display unit of the reflective display device 100 and irradiates the reflective display device 100 with light, in which a first transparent resin substrate 265 and a second transparent resin substrate 215 are used for the direct illumination unit 200, and an EPD (electrophoretic display) is used as the reflective display device 100.

[0194] The direct illumination unit 200 is disposed so that the first transparent substrate 260 side of the direct illumination unit 200 faces the display unit of the reflective display device 100 .

[0195] The direct-type illumination unit 200 in the fifth embodiment is an organic electroluminescence element including a first transparent resin substrate 265, a second transparent resin substrate 215 facing the first transparent resin substrate 265, a second thin-film sealing layer 271 laminated on the viewing side of the first transparent resin substrate 265, an anode 250 arranged on the viewing side of the second thin-film sealing layer 271 to form a periodic pattern, an organic layer 240 laminated on the viewing side of the anode 250, and a cathode 230 arranged on the viewing side of the organic layer 240 to form a periodic pattern. Furthermore, a first thin-film sealing layer 270 is formed on the viewing side of the cathode 230, the organic layer 240, the anode 250, and the anode-connecting electrode 251, and a cathode antireflection layer 220 is laminated on the viewing side of the first thin-film sealing layer 270 so as to cover the cathode 230 and the anode-connecting electrode 251, and a second transparent resin substrate 215 is laminated via a first resin layer 211. An antireflection layer 280 is laminated on the viewing side of the second transparent resin substrate 215.

[0196] The reflective display device 100 includes a TFT substrate 150 provided on the display unit side of the reflective display device 100, a counter substrate 120 arranged to face the TFT substrate 150, an EP (electrophoretic) microcapsule layer 131 (display layer) provided between the TFT substrate 150 and the counter substrate 120, and a display electrode 141 arranged in a periodic pattern on the viewing side surface of the TFT substrate 150. The display electrode 141 is made of ITO, Al, or the like. The display electrode 141 may have a reflective function, but does not necessarily have to have a reflective function.

[0197] The light scattering layer 300 is laminated between the polarizing plate 110 and the opposing substrate 120, but is not limited to this position, and may be laminated on the viewing side of the display layer (liquid crystal layer 130) and on the reflective display device 100 side of the anode 250 of the direct illumination section 200.

[0198] In the fifth embodiment, a display device 1d uses an EPD for the reflective display device 100, thereby providing a display device with excellent visibility regardless of the surrounding environment. Furthermore, in the display device 1d, an EPD is used for the reflective display device 100, and a transparent resin substrate is adopted for the direct irradiation section, thereby providing a thin, lightweight reflective display device (or display device) with excellent visibility regardless of the surrounding environment. [Example]

[0199] Specific examples are given below, but the present invention is not limited to these. For each evaluation, an organic electroluminescence element (referred to as direct-type lighting unit-1) having the layered structure shown in Fig. 5 was used as the direct-type lighting unit. The configuration of the direct-type lighting unit is summarized below. First transparent substrate (260 in Figure 5): 300 μm thick (material: glass substrate) Second transparent substrate (210 in Figure 5): 300 μm thick (material: glass substrate) Anode (250 in Figure 5): 300 nm thick layered anode (material: ITO) Organic layer (240 in FIG. 5, consisting of an electron transport layer 241, a light-emitting layer 242, and a hole transport layer 243): thickness 200 μm (manufactured by Idemitsu Kosan Co., Ltd.) First thin-film encapsulation layer (270 in Figure 5): Thickness 600 nm (material of thin-film encapsulation layer: SiO2) Cathode (230 in Figure 5): Thickness 300 nm (Material: Aluminum) Cathode pattern shape: Pitch (P1) 200 μm, pattern width 20 μm, stripe shape First resin layer (211 in Figure 5): Thickness 20 μm (Material: Acrylic resin) Cathode anti-reflection layer (220 in Figure 5): Thickness 20 μm (Material: Black resist, manufactured by Tokyo Ohka Kogyo Co., Ltd.) Cathode anti-reflection layer pattern: L1 and L2 are 2 μm for the cathode pattern Anti-reflection layer (280 in Figure 5): 28 μm thick LR film (material: triacetyl cellulose) Second resin layer (261 in Figure 5): Thickness 100 μm (Material: Acrylic adhesive)

[0200] For each evaluation, a reflective liquid crystal display device (referred to as reflective LCD-1) having the layered structure shown in Figure 5 was used as the reflective display device. The configuration of the reflective display device is summarized below. Polarizing plate (110 in Figure 5): NPF series (manufactured by Nitto Denko Corporation) Fourth transparent substrate (120 in Figure 5): 300 μm thick (material: alkali-free glass) Liquid crystal layer (display layer) (130 in Figure 5): 5 μm thick (Merck) Third transparent substrate (150 in Figure 5): 300 μm thick (material: alkali-free glass) Reflective pixel electrode (140 in Figure 5): rectangular shape, 106.5 μm long x 35.5 μm wide, 300 nm thick (material: aluminum) Pattern shape of reflective pixel electrode: pitch (P2) 106.5 μm, island shape (same arrangement as in Figure 3, P1 and P1' are P2 and P2', respectively. Also, P2 = P2')

[0201] Light-scattering layers (light-scattering layer-1 to light-scattering layer-5) were prepared with reference to International Publication No. WO2020 / 203643. The anisotropic light-scattering layer was prepared with reference to the description of the anisotropic light-diffusing layer in the international application, and the isotropic light-scattering layer was prepared with reference to the description of the isotropic light-diffusing layer in the international application. Additionally, ultraviolet light, which is a parallel beam of light, was used to prepare the anisotropic light-scattering layer. The parameters of the light scattering layer used in each evaluation are shown in Table 1.

[0202] <Display device configuration> Table 2 shows the combinations of direct illumination units, reflective display devices, and light-scattering layers for display devices-1 to -6 used in the evaluation. Table 2 also shows the values ​​of P1, P2, D1, D2, 2×D1×tan(θ1 / 2), and 2×D2×tan(θ1 / 2) for display devices-1 to -6. D1 and D2 were adjusted by adjusting the thickness of the light-scattering layer.

[0203] <Measurement of each parameter of the light scattering layer> (Scattering angle θ1, scattering central axis angle θ2, linear transmittance at incident angle 0°, maximum linear transmittance, minimum linear transmittance) The scattering angle θ1, scattering central axis angle θ2, linear transmittance at an incident angle of 0°, maximum linear transmittance, and minimum linear transmittance of optical scattering layer-1 to light scattering layer-5 were measured by creating an optical profile of each optical scattering layer using the method described above, and reading each numerical value from the created optical profile (graph). The results are shown in Table 1.

[0204] (Haze value (Hz)) The measurement was carried out according to the method described in JIS K7136:2000 "Determination of haze of plastics - transparent materials."

[0205] <Evaluation of Display Devices of Examples and Comparative Examples> Display devices 1 to 6 were divided into examples and comparative examples, and the presence and strength of moiré and the visibility of the display devices were checked with the naked eye. Regarding the visibility evaluation, display devices where moiré was visible were rated as "poor," and among display devices where moiré was not visible, display devices where image blur was relatively strong were rated as "good," and display devices where image blur was weakly visible were rated as "very good." These results are shown in Table 3.

[0206] [Table 1]

[0207] [Table 2]

[0208] [Table 3] [Explanation of symbols]

[0209] 1, 1', 1'', 1a, 1b, 1c, 1d display device, 10 light source, 20 detector, 100 reflective display device, 110 polarizer, 120 fourth transparent substrate (counter substrate), 130 liquid crystal layer (display layer), 131 EP microcapsule layer (display layer), 140 reflective pixel electrode, 141 display electrode, 150 third transparent substrate (TFT substrate), 200 direct illumination unit, 210 second transparent substrate, 211 first resin layer, 215 second transparent substrate made of resin (second transparent resin substrate), 220 cathode anti-reflection layer, 230 cathode, 240 organic layer, 241 electron transport layer, 242 light-emitting layer, 243 hole transport layer, 250 anode, 251 anode connecting electrode, 260 first transparent substrate, 261 Second resin layer, 265: First transparent substrate made of resin (first transparent resin substrate), 270: First thin film sealing layer, 271: Second thin film sealing layer, 280: Anti-reflection layer, 290: Polarizer for cathode anti-reflection, 300: Light scattering layer, 310: Matrix region, 320: Structure region, I: Irradiation light, V: Straight line (rotation axis).

Claims

1. a direct illumination unit that is arranged on the viewing side of the reflective display device and that irradiates light onto the reflective display device; the reflective display device includes, facing a viewer side, a third transparent substrate, reflective pixel electrodes arranged in a periodic pattern on a surface of the third transparent substrate on the viewer side, and a fourth transparent substrate facing the third transparent substrate; the direct illumination unit is an organic electroluminescence element including, facing a viewing side, a first transparent substrate, an anode, an organic layer, a cathode arranged to form a periodic pattern, and a second transparent substrate facing the first transparent substrate; the organic layer includes an emitting layer, a light scattering layer disposed closer to the viewer than the fourth transparent substrate and closer to the reflective display device than the first transparent substrate; The pitch between the cathode patterns is P １ , the pitch between the patterns of the reflective pixel electrodes is P ２ , the shortest distance from the surface of the light scattering layer on the viewing side to the surface of the reflective pixel electrode on the viewing side is D １ , the shortest distance from the surface of the light scattering layer on the reflective pixel electrode side to the surface of the cathode on the reflective pixel electrode side is D ２ The scattering angle of the light incident on the light scattering layer is θ １ and (2) are satisfied. (1)P ２ ≦2×D １ ×tan(θ) １ / 2) (2)P １ ≦2×D ２ ×tan(θ) １ / 2)

2. The P １ and the above P ２ 2. The display device according to claim 1, wherein one of said and said is a natural number multiple of the other.

3. The P １ and the above P ２ 2. The display device according to claim 1, wherein one of the above is not a natural number multiple of the other.

4. 4. The display device according to claim 1, wherein the light scattering layer is an anisotropic light scattering layer in which the amount of emitted light changes depending on the angle of incidence of light.

5. 4. The display device according to claim 1, wherein the light scattering layer is an isotropic light scattering layer in which the amount of emitted light does not change depending on the angle of incidence of light.

6. 5. The display device according to claim 4, wherein the anisotropic light-scattering layer has a matrix region and a structural region provided within the matrix region, extending in a thickness direction of the matrix region, and having a refractive index different from that of the matrix region.

7. 7. The display device according to claim 6, wherein the structural region is a plurality of columnar structures extending in a thickness direction of the matrix region.

8. The anisotropic light-scattering layer has a scattering central axis that is an axis of symmetry regarding light scattering, and a scattering central axis angle θ that is an angle formed between a normal to the anisotropic light-scattering layer and the scattering central axis. ２ 5. The display device according to claim 4, wherein the angle is 0° to 40°.

9. 5. The display device according to claim 4, further comprising a cathode anti-reflection layer on the viewer side of the cathode for blocking light reflected from the cathode.

10. 6. The display device according to claim 5, further comprising a cathode anti-reflection layer on the viewer side of the cathode for blocking light reflected from the cathode.

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