JP2013134907A - Organic electroluminescence display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic EL display device which can extract light with high efficiency and provides a display image having no bleeding, distortion, color unevenness and the like.SOLUTION: The organic EL display device is a display device which includes an organic EL element, and a phaser, a polarizer and a light emitting surface structure layer provided on a light emitting surface side of the organic EL element. The phaser and the polarizer are provided in this order from the organic EL element side. The light emitting surface structure layer has an uneven structure having a flat surface portion parallel to one surface of the organic EL element and a slope portion tilted against the flat portion on the surface on an opposite side to the organic EL element. A projected area formed by projecting the slope portion onto a plane parallel to the flat surface portion in a direction perpendicular to the flat surface portion is equal to or less than the total area of the flat surface portion.

Description

  The present invention relates to a display device. Specifically, the present invention relates to an organic electroluminescence display device (hereinafter referred to as “organic EL display device”) including an organic electroluminescence element (hereinafter referred to as “organic EL element” as appropriate).

  An organic EL device that provides an organic light emitting layer between multiple layers of electrodes to obtain light emission is an element of a display device that takes advantage of features such as high light emission efficiency, low voltage drive, light weight, and low cost instead of a liquid crystal cell. It is used as. An organic EL display device including an organic EL element has a configuration in which an organic layer capable of emitting light is sandwiched between electrodes, and generally has a hole transport layer, a light emitting layer, and an electron transport layer laminated. As the electrodes, a transparent electrode (for example, ITO) is used on the light extraction side, and a reflective electrode (for example, aluminum) is used for the opposing electrode. Electrons and holes can be injected from both electrodes into the light emitting layer through the electron transport layer and the hole transport layer, and the electrons and holes can be recombined in the light emitting layer to emit light.

  However, an organic EL display device using a reflective electrode has a problem that external light is reflected by the reflective electrode, resulting in a decrease in contrast. For this reason, there has been known a method of preventing reflection of external light at the reflective electrode by providing a circularly polarizing plate on the light emitting surface side (Patent Document 1). As the circularly polarizing plate used here, a circularly polarizing plate in which a quarter wave plate and a linearly polarizing plate are combined is exemplified, but light emission from the organic EL element is also absorbed by the circularly polarizing plate, and the luminous efficiency is improved. It has been a problem that it falls.

  On the other hand, it is known to improve the light extraction efficiency by providing various uneven structures on the light exit surface side of the organic EL element. Many studies have been made on such a concavo-convex structure, particularly in a single-sided emission type surface light source device that extracts light from one side (Patent Document 2).

Japanese Patent No. 9-127858 JP 2009-266429 A

  However, for the purpose of improving the light extraction efficiency, when an uneven structure used in a surface light source device is provided on an organic EL display device having a circularly polarizing plate, blurring, distortion, color, etc. appear on the display image such as characters. There may be unevenness. The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an organic EL display device that can extract light with high efficiency and at the same time has performance required as a display device. .

As a result of intensive studies to solve the above-described problems, the present inventors have determined that by controlling the area ratio between the flat surface portion and the slope portion of the concavo-convex structure in the organic EL display device having the concavo-convex structure on the light output surface. The present invention was completed by finding that an organic EL display device that can extract light with high efficiency and at the same time has no blurring, distortion, or color unevenness in a display image can be realized.
That is, the gist of the present invention is the following [1] to [6].

[1] A display device comprising an organic electroluminescence element and a phase shifter, a polarizer, and a light emission surface structure layer provided on the light emission surface side of the organic electroluminescence element,
The phaser and the polarizer are installed in the order of the phaser and the polarizer from the organic electroluminescence element side,
The light-emitting surface structure layer has an uneven surface having a flat surface portion parallel to one surface of the organic electroluminescence element and a slope portion inclined with respect to the flat portion on the surface opposite to the organic electroluminescence element. Has a structure,
A projected area formed by projecting the slope portion in a direction perpendicular to the flat surface portion onto a plane parallel to the flat surface portion is 1.0 times or less of the total area of the flat surface portions. An organic electroluminescence display device.

[2] Organic electroluminescence device, phase shifter, polarizer, light emitting surface structure layer in this order,
Alternatively, the organic electroluminescence display device according to [1], wherein the organic electroluminescence element, the light emitting surface structure layer, the phase shifter, and the polarizer are arranged in this order.
[3] The organic electroluminescence display device according to [1] or [2], further comprising a retardation film on the light exit surface side of the polarizer.

[4] The organic electroluminescence display device according to any one of [1] to [3], wherein the maximum height difference of the flat surface portion in the concavo-convex structure is 12 μm or less.
[5] The organic electroluminescence display device according to any one of [1] to [4], wherein the inclined surface portion is inclined at an inclination angle of 45 ° or more and less than 90 ° with respect to the flat surface portion.
[6] The organic electroluminescence display device according to any one of [1] to [5], wherein the height difference of the flat surface portion is 0.1 μm or more.

  The organic EL display device of the present invention can extract light with high efficiency, and can reduce blurring, distortion, color unevenness, and the like of an image.

FIG. 1 is a perspective view schematically showing an organic EL display device according to a first embodiment of the present invention. FIG. 2 is a diagram for explaining the organic EL display device according to the first embodiment of the present invention, in which the organic EL display device shown in FIG. 1 is cut along a plane perpendicular to the outgoing surface through line 1a-1b. It is sectional drawing which shows a cross section typically. FIG. 3 is a partial plan view schematically showing an enlarged view of a part of the light emission surface of the organic EL display device according to the first embodiment of the present invention as viewed from the thickness direction of the organic EL display device. FIG. 4 is a partial cross-sectional view schematically showing a cross section obtained by cutting the concavo-convex structure layer according to the first embodiment of the present invention along a plane that passes through the line 3a of FIG. 3 and is perpendicular to the light exit surface. FIG. 5 schematically shows a state in which the slope portion of the light exit surface of the organic EL display device according to the first embodiment of the present invention is projected onto a plane parallel to the flat surface portion in a direction perpendicular to the flat surface portion. FIG. FIG. 6 is a perspective view schematically showing an organic EL display device according to the second embodiment of the present invention. FIG. 7 is a diagram for explaining an organic EL display device according to a second embodiment of the present invention, in which the organic EL display device shown in FIG. 6 is cut along a plane perpendicular to the outgoing surface through lines 6a-6b. It is sectional drawing which shows a cross section typically. FIG. 8 is a partial plan view schematically showing an enlarged view of a part of the light emission surface of the organic EL display device according to the second embodiment of the present invention as viewed from the thickness direction of the organic EL display device. FIG. 9 is a partial cross-sectional view schematically showing a cross section of the concavo-convex structure layer according to the second embodiment of the present invention cut along a plane that passes through the line 8a of FIG. 8 and is perpendicular to the light exit surface. FIG. 10 is a top view schematically showing the surface light source device according to the third embodiment of the present invention viewed from the thickness direction. FIG. 11 is a diagram for explaining a surface light source device according to the third embodiment of the present invention. The surface light source device shown in FIG. 10 is a surface perpendicular to the light exit surface 30U that passes through the line 10a in FIG. It is sectional drawing which shows the cut | disconnected cross section. FIG. 12 is a schematic cross-sectional view for explaining an organic EL display device according to the fourth embodiment of the present invention. FIG. 13 is a schematic cross-sectional view for explaining an organic EL display device according to a fifth embodiment of the present invention. FIG. 14 is a schematic cross-sectional view for explaining an organic EL display device according to a sixth embodiment of the present invention. FIG. 15 is a schematic cross-sectional view for explaining another organic EL display device according to the sixth embodiment of the present invention. FIG. 16 is a cross-sectional view schematically showing a cross section of a concavo-convex structure layer according to another embodiment of the present invention. FIG. 17 is a cross-sectional view schematically showing a cross section of a concavo-convex structure layer according to another embodiment of the present invention. FIG. 18 is a cross-sectional view schematically showing a cross section of a concavo-convex structure layer according to another embodiment of the present invention. FIG. 19 is a diagram schematically illustrating a state of manufacturing the metal mold used in Example 1. FIG. 20 is a diagram schematically showing a cross-section of the concavo-convex structure layer in Example 1 cut along a plane perpendicular to the cutting direction.

  Hereinafter, the present invention will be described in detail with reference to embodiments and examples, but the present invention is not limited to the embodiments and examples described below, and the gist of the present invention and its equivalent scope. Any change can be made without departing from the scope of the invention. In particular, with respect to the concavo-convex structure, a mode in which the position, orientation, shape, number, and combination of the flat surface portion and the slope portion are changed can be considered as long as the effects of the present invention are not impaired.

[1. First embodiment]
1 and 2 are diagrams for explaining an organic EL display device according to a first embodiment of the present invention. FIG. 1 is a perspective view schematically showing the display device, and FIG. It is sectional drawing which shows typically the cross section which cut | disconnected the display apparatus shown by the surface perpendicular | vertical with respect to the light emission surface through line 1a-1b.

As shown in FIG. 1, the organic EL display device 10 according to the first embodiment of the present invention is a device having a rectangular flat plate structure, and includes an organic EL element 140 and one surface of the organic EL element 140. The phaser 130, the polarizer 120, and the light exit surface structure layer 110 are provided. The organic EL element 140 includes at least a transparent electrode layer 141, a light emitting layer 142, and a reflective electrode layer 143. Furthermore, the organic EL display device 10 of the present embodiment may include components in addition to the members described above. The surface 10U is located on the outermost side of the organic EL display device 10, and light is emitted from the surface 10U to the outside of the display device 10. Therefore, the surface 10U is referred to as a “light emitting surface”.

[1-1. (Light emitting surface structure layer)
The light exit surface structure layer 110 includes a light exit surface 10U located on the outermost side of the organic EL display device 10. The light exit surface 10U is the surface opposite to the organic EL element 140 of the light exit surface structure layer 110, and the light exit surface as the organic EL display device 10, that is, when light is emitted from the organic EL display device 10 to the outside of the device. This is the light exit surface.

When viewed macroscopically, the light exit surface 10U is a surface parallel to the light emitting surface 144 of the organic EL element 140 and parallel to the main surface of the organic EL display device 10. However, since the light exit surface 10U has a concave-convex structure described later when viewed microscopically, the surface on the concave portion or the convex portion can form an angle that is not parallel to the light emitting surface 144. Therefore, in the following description, being parallel or perpendicular to the light exit surface means that it is parallel or perpendicular to the light exit surface viewed macroscopically ignoring the recesses or projections unless otherwise specified. Say. Further, the organic EL display device 10 will be described in a state where the light exit surface 10U is placed so as to be parallel to the horizontal direction and upward unless otherwise specified.
Further, the fact that the component is “parallel” or “vertical” may include an error within a range that does not impair the effects of the present invention, for example, ± 5 °.

In the present embodiment, the light exit surface structure layer 110 includes an uneven structure layer 111 and a base film layer 112.
The concavo-convex structure layer 111 is a layer located on one surface of the organic EL display device 10 (that is, the outermost layer on one light emitting surface side of the organic EL display device 10, the upper side in the drawing). A concavo-convex structure is formed on the light output surface 10U which is the surface of the concavo-convex structure layer 111. Although the concavo-convex structure will be described in detail later, the concavo-convex structure is composed of flat surface portions 113 and 114 that are parallel to the light emitting surface 144 of the organic EL element 140 and inclined surface portions 115 that are inclined with respect to the flat surface portions 113 and 114. It is comprised by.
Specifically, the light exit surface 10U of the concavo-convex structure layer 111 has a plurality of concave portions 116 having the flat surface portion 114 as a bottom surface and a slope portion 115 as a side surface, and a flat surface portion 113 corresponding to a gap portion between adjacent concave portions 116. And is configured. Here, that the slope portion is inclined with respect to the flat surface portion means that the slope portion is not parallel to the flat surface portion.

  In the present specification, since the drawings are schematic, only a small number of recesses 116 are shown on the light exit surface 10U. However, in an actual organic EL display device, one organic A much larger number of recesses can be provided on the light exit surface of the EL display device.

(Description of uneven structure)
Hereinafter, the uneven structure of the light exit surface 10U will be described in detail with reference to the drawings.
FIG. 3 is a partial plan view schematically showing an enlarged view of a part of the light exit surface 10U of the organic EL display device 10 as viewed from the thickness direction of the organic EL display device 10. FIG. 4 is a partial cross-sectional view schematically showing a cross section of the concavo-convex structure layer 111 taken along a plane that passes through the line 3a of FIG. 3 and is perpendicular to the light exit surface 10U. The line 3a is a line passing over all the flat surface portions 114 of the recesses 116 in one row. In the following description, “thickness direction” refers to the thickness direction of the organic EL display device unless otherwise specified.

  As shown in FIG. 3, the light exit surface 10 </ b> U includes a plurality of concave portions 116 and a flat surface portion 113 that is a gap portion between the concave portions 116. Each recess 116 has a shape (pyramidal trapezoidal shape) obtained by cutting the top of a regular quadrangular pyramid parallel to the bottom surface. Each recess 116 includes a rectangular flat surface portion 114 corresponding to the bottom portion thereof, and four inclined surface portions 115 extending from the four sides of the rectangle. More specifically, the flat surface portion 114 that is the bottom surface of the concave portion 116 has a square shape. Moreover, all of the four slopes 115 constituting the recess 116 have the same trapezoidal shape. Further, a boundary line 117 between the slope 115 and the flat surface 113 forms a square. That is, in the present embodiment, the recess 116 has a regular quadrangular pyramid shape.

  The recesses 116 are usually provided so that the positions are discrete. Here, the plurality of recesses 116 are arranged along two directions X and Y that are parallel to the light exit surface 10U and orthogonal to each other. Specifically, the recesses 116 are continuously arranged along two orthogonal directions X and Y with a certain interval L therebetween. In the two directions X and Y, a gap is provided between the adjacent recesses 116, and the gap constitutes the flat surface portion 113. Therefore, on the light exit surface 10U, the slope portion 115 is usually located around the flat surface portion 114, and the flat surface portion 113 is located around the slope portion 115 (and thus around the recess 116).

   FIG. 5 shows a state in which the slope 115 of the light exit surface 10U of the organic EL display device 10 is projected onto a plane 900 parallel to the flat surfaces 113 and 114 in a direction perpendicular to the flat surfaces 113 and 114. It is a projection figure shown typically. In the present embodiment, the direction perpendicular to the flat surface portions 113 and 114 coincides with the direction perpendicular to the light exit surface 10U and the direction parallel to the thickness direction of the organic EL display device 10. Further, the plane 900 parallel to the flat surface portions 113 and 114 is a plane parallel to the light exit surface 10U. However, the plane 900 parallel to the flat surface portions 113 and 114 is not a plane that the organic EL display device 10 has, but a projection plane that is set to measure the projection area of the slope portion 115. Further, in FIG. 5, the slope 115 of the light exit surface 10U of the organic EL display device 10 is projected onto a plane 900 parallel to the flat surfaces 113 and 114 in a direction perpendicular to the flat surfaces 113 and 114. The projected image 901 is shown with diagonal lines.

  As shown in FIG. 5, in the organic EL display device 10 according to the present embodiment, the slope 115 is formed in a direction perpendicular to the flat surfaces 113 and 114 and into a plane 900 parallel to the flat surfaces 113 and 114. The projected area formed by projection is usually 1.0 times or less, preferably 0.8 times or less, more preferably 0.5 times or less the total area of the flat surface portions 113 and 114. Further, the lower limit of the ratio of the projected area of the slope 115 to the total area of the flat surface portions 113 and 114 is usually 0.0001 times or more, preferably 0.0005 times or more, more preferably 0.001 times or more.

  When the light-emitting surface 10U has the uneven structure as described above, the organic EL display device 10 of the present embodiment can exhibit the following effects (i) to (iii).

  (I) In the organic EL display device 10, the light extraction efficiency from the light exit surface 10 </ b> U can be increased as compared with the case where the uneven structure is not provided. That is, even if the light that could not be extracted by internal reflection at the flat surface portions 113 and 114 can be extracted from the inclined surface portion 115, the light extraction efficiency can be improved.

  (Ii) It is possible to prevent the concavo-convex structure from being broken due to an external impact, and as a result, the mechanical strength of the light exit surface 10U can be improved. In general, when a surface has a concavo-convex structure, when an impact is applied to the surface, the force concentrates on a part of the concavo-convex structure and tends to cause breakage. However, in the organic EL display device 10 of the present embodiment, the flat surface portion 113 has a uniform and flat surface in the thickness direction (hereinafter, referred to as “height position” as appropriate), and therefore the light exit surface 10U from the outside. It is possible to prevent the force from being concentrated on a part of the concavo-convex structure layer 111 due to a force applied to or a shock. For this reason, damage to the concavo-convex structure layer 111 can be prevented, and both good light extraction efficiency and high mechanical strength of the light output surface 10U of the organic EL display device 10 can be achieved at the same time.

  (Iii) Due to the reason of suppressing haze when viewed from the front direction, there is no blurring or distortion of characters, and visibility is good.

  Furthermore, as shown in FIG. 4, the maximum value of the height difference H (the depth of the recess 116 in this embodiment) H between the flat surface portion 113 and the flat surface portion 114 in the light exit surface 10U is preferably 12 μm or less, and 11 μm or less. Alternatively, it can be 10 μm or less. The lower limit is usually 0.1 μm or more, and can be 0.15 μm or more or 0.2 μm or more.

  By keeping the maximum value of the height difference H of the flat surface portions 113 and 114 within such a range, the organic EL display device 10 can be viewed even when viewed from a direction (oblique direction) inclined with respect to the normal direction of the light exit surface 10U. The visibility becomes better. When the area ratio of the slope 115 is large, the haze tends to increase when the light exit surface 10U is viewed from an oblique direction. On the other hand, the ratio of the projected area of the inclined surface portion 115 to the total area (total area) of the flat surface portions 113 and 114 falls within the above range, and the maximum value of the height difference H between the flat surface portions 113 and 114 is within the above range. Since the haze can be suppressed when viewed from an oblique direction, the visibility can be maintained even when the organic EL display device 10 is viewed from the oblique direction.

  As shown in FIG. 4, the slope 115 is usually 45 ° or more, preferably 46 ° or more, more preferably 47 ° or more, and usually less than 90 °, preferably 89 ° with respect to the flat surface portions 113 and 114. In the following, it is preferable to incline at an inclination angle θ of 88 ° or less. That is, the slope 115 is a surface that is not parallel to the flat surfaces 113 and 114, but the angle θ formed by the slope 115 and the flat surfaces 113 and 114 is preferably within the above range. As described above, since the inclination angle θ of the slope 115 is large, the light extraction efficiency can be stably increased. In addition, when the inclination angle θ is large, the projected area per inclined portion 115 can be reduced when the inclination angle θ is small. Therefore, when viewed from a direction perpendicular to the light exit surface 10U, the organic EL display device The visibility of 10 can be improved. The direction perpendicular to the light exit surface 10U corresponds to the front direction of the organic EL display device 10, and it is normally assumed that the frequency of viewing the organic EL display device 10 from this front direction is high. Useful.

  Moreover, in this embodiment, although the inclination | tilt angle (theta) of all the slope parts 115 is set to the same magnitude | size, it does not specifically limit and may differ.

  The thickness T of the concavo-convex structure layer 111 may be set in an appropriate range in relation to the maximum value of the height difference H of the flat surface portions 113 and 114. For example, when a hard material that is advantageous for maintaining the durability of the concavo-convex structure layer 111 is used as the material of the concavo-convex structure layer 111, the thickness of the concavo-convex structure layer 111 is made thinner so that the flexibility of the organic EL display device 10 is improved. This is preferable because the uneven structure layer 111 can be easily handled in the manufacturing process of the organic EL display device 10. Specifically, the difference between the maximum height difference H of the flat surface portions 113 and 114 and the thickness T of the concavo-convex structure layer 111 is preferably 0 to 30 μm.

  As shown in FIG. 3, the light exit surface 10U has a shape in which a repeating structure including flat surface portions 113 and 114 and two slope portions 115 is repeatedly arranged along the two directions X and Y, respectively. For example, in the direction X, as shown in FIG. 4, a repeating structure 118 in which the flat surface portion 113, the inclined surface portion 115, the flat surface portion 114, and the inclined surface portion 115 are arranged in this order is repeatedly formed. The pitch P of such a repeating structure 118 is usually 0.1 μm or more, preferably 0.15 μm or more, more preferably 0.2 μm or more, and usually 500 μm or less, preferably 450 μm or less, more preferably 400 μm or less. . When the pitch P is equal to or greater than the lower limit of the above range, there is an advantage that the extraction efficiency is improved because the structural effect of changing the traveling direction of light appears. In addition, when the thickness of a general organic EL display device is taken into consideration when the pitch P is equal to or less than the upper limit of the above range, there is an advantage that the extraction efficiency is improved because the probability that light is reflected and refracted at the inclined surface portion is increased. There is.

The thickness T of the uneven structure layer 111 is not particularly limited, but is preferably 1 μm to 70 μm. In the present embodiment, the thickness T of the concavo-convex structure layer 111 is a distance between the surface on the base film layer 112 side where the concavo-convex structure is not formed and the flat surface portion 113.
Moreover, it is preferable that the thickness of the base film layer 112 is 20 micrometers-300 micrometers.

(Explanation of light emitting surface structure layer material)
The light exit surface structure layer 110 may be composed of a plurality of layers, but may be composed of a single layer. From the viewpoint of easily obtaining the light-emitting surface structure layer 110 having desired characteristics, it is preferable that the light-emitting surface structure layer 110 is composed of a plurality of layers. In the present embodiment, as shown in FIG. 1, the light exit surface structure layer 110 includes an uneven structure layer 111 and a base film layer 112. Thereby, the light emission surface structure layer 110 with high performance can be obtained easily.

  The concavo-convex structure layer 111 and the base film layer 112 can usually be formed of a resin composition containing a transparent resin. In the present embodiment, each layer constituting the light exit surface structure layer 110 may have a light transmittance suitable for use in an optical member. For example, the light exit surface structure layer 110 as a whole is 80% or more in total. What is necessary is just to have a light transmittance.

  The transparent resin contained in the resin composition is not particularly limited, and various resins that can form a transparent layer can be used. Examples thereof include a thermoplastic resin, a thermosetting resin, an ultraviolet curable resin, and an electron beam curable resin. Among these, thermoplastic resins are preferable because they can be easily deformed by heat, and ultraviolet curable resins have high curability and high efficiency, so that the uneven structure layer 111 can be efficiently formed.

  Examples of the thermoplastic resin include polyester, polyacrylate, and cycloolefin polymer resins. Examples of the ultraviolet curable resin include epoxy resins, acrylic resins, urethane resins, ene / thiol resins, and isocyanate resins. As these resins, those having a plurality of polymerizable functional groups can be preferably used. In addition, the said resin may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  Among them, the material of the concavo-convex structure layer 111 constituting the light exit surface structure layer 110 is high in hardness at the time of curing from the viewpoint of easily forming the concavo-convex structure of the light output surface 10U and easily obtaining scratch resistance of the concavo-convex structure. Material is preferred. Specifically, when a resin layer having a film thickness of 7 μm is formed on a substrate without a concavo-convex structure, a material having a pencil hardness of HB or higher is preferable, and a material of H or higher is more preferable. The material which becomes 2H or more is more preferable. On the other hand, as the material of the base film layer 112, in order to facilitate handling when forming the uneven structure layer 111 and handling the light exit surface structure layer 110 after forming the light exit surface structure layer 110, a certain amount of material is used. What has flexibility is preferable. By combining such materials, the light-emitting surface structure layer 110 that is easy to handle and excellent in durability can be obtained. As a result, the high-performance organic EL display device 10 can be easily manufactured.

  Such a combination of materials can be obtained by appropriately selecting the transparent resin exemplified above as the resin constituting each material. Specifically, an ultraviolet curable resin such as acrylate is used as the transparent resin constituting the material of the concavo-convex structure layer 111, while the transparent resin constituting the material of the base film layer 112 is made of an alicyclic olefin polymer. It is preferable to use a film (such as a ZEONOR film described later) or a polyester film. Further, the concavo-convex structure layer may be provided directly on the phase shifter and may be arranged in the order of organic EL element / phase shifter / unevenness structure layer / polarizer, or organic EL element / relief structure layer / phase shifter / polarizer. . Such a configuration has a large effect of improving the light extraction efficiency compared with the case where there is a concavo-convex structure layer on the viewing side of the polarizer, and at the same time, the overall thickness is reduced and the boundary between each layer is reduced. The transmittance can be increased. As described above, the concavo-convex structure layer disposed between the polarizer and the light emitting element is preferably a more isotropic material and has a thin thickness, and desirably the phase difference or the phase difference variation is within 20 nm. Preferably, it is within 10 nm, more preferably within 5 nm.

  When the light-emitting surface structure layer 110 includes the concavo-convex structure layer 111 and the base film layer 112 as in this embodiment, the refractive index of the concavo-convex structure layer 111 and the base film layer 112 may be as close as possible. . In this case, the refractive index difference between the uneven structure layer 111 and the base film layer 112 is preferably within 0.1, and more preferably within 0.05.

As a material of a layer that is a constituent element of the light exit surface structure layer 110 such as the concavo-convex structure layer 111 and the base film layer 112, a material having light diffusibility may be used as long as visibility is not hindered.
Thereby, the light which permeate | transmits the light emission surface structure layer 110 can be diffused, maintaining visibility, and malfunctions, such as a change of the color according to an observation angle, can further be reduced.

  Examples of the light diffusing material include a material containing particles, and an alloy resin that diffuses light by mixing two or more kinds of resins. Among these, from the viewpoint that the light diffusibility can be easily adjusted, a material including particles is preferable, and a resin composition including particles is particularly preferable.

The particles may be transparent or opaque. Examples of the material of the particles include metals and metal compounds, and resins. Examples of the metal compound include metal oxides and nitrides. Specific examples of metals and metal compounds include metals having high reflectivity such as silver and aluminum; metal compounds such as silicon oxide, aluminum oxide, zirconium oxide, silicon nitride, tin-added indium oxide, and titanium oxide. be able to. On the other hand, examples of the resin include methacrylic resin, polyurethane resin, and silicone resin. In addition, the particle | grain material may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  The shape of the particles can be, for example, a spherical shape, a cylindrical shape, a cubic shape, a rectangular parallelepiped shape, a pyramid shape, a conical shape, a star shape, or the like.

  Furthermore, the resin composition can contain arbitrary components as needed. Examples of the optional component include additives such as phenol-based and amine-based degradation inhibitors; surfactant-based, siloxane-based antistatic agents; triazole-based, 2-hydroxybenzophenone-based light-resistant agents; Can be mentioned.

[1-2. Organic EL device]
The organic EL display device of the present invention includes an organic EL element including a light emitting layer. The organic EL element can be an element including two or more electrode layers and one or more light emitting layers that are provided between these electrode layers and emit light when voltage is applied from the electrodes.

  The organic EL element has a structure in which layers such as an electrode and a light-emitting layer constituting the element are formed on a substrate, and a sealing member that covers these layers is further provided and sealed with the substrate and the sealing member. It is common. Usually, the element that emits light from the substrate side here is called a bottom emission type, and the element that emits light from the sealing member side is called a top emission type. Any of these may be sufficient as the organic EL display device of this invention. In the case of the bottom emission type, a substrate for an organic EL element or a combination of such a substrate and an arbitrary layer (a layer existing between the substrate and the organic EL element) constitutes a part of the light emission efficiency improving unit. On the other hand, in the case of the top emission type, a structure on the device light exit surface side such as a sealing member constitutes a part of the light output efficiency improving portion.

In this invention, it does not specifically limit as a light emitting layer which comprises an organic EL element, A well-known thing can be selected suitably. The light-emitting material in the light-emitting layer is not limited to one type, and the light-emitting layer is not limited to one layer, and may be a single layer or a combination of a plurality of layers in order to suit the use as a light source. Thereby, light of white color (specifically, for example, a color temperature range of 3000 to 6500 K) or a color close thereto can be emitted.
In the present invention, in particular, the object is to reduce the change in color depending on the observation angle. Therefore, the light emitting layer preferably has two or more emission peaks or emits light in a wide wavelength range. Therefore, the light emitting layer is preferably one or more layers containing two or more kinds of light emitting materials. More specifically, the light emitting layer preferably emits white light.

  As a light emitting layer, it does not specifically limit but a known thing can be selected suitably. The light emitting material in the light emitting layer is not limited to one type, and two or more types may be used in combination at any ratio. In addition, the light emitting layer is not limited to one layer, and may be a single layer alone or a combination of a plurality of layers in order to be suitable for use as a light source. Thereby, light of white or a color close thereto can be emitted.

  The electrode of the organic EL element is not particularly limited, and a known one can be appropriately selected. Like the organic EL element 140 according to the first embodiment, the electrode 141 on the light exit surface structure layer 110 side is a transparent electrode, and the electrode 143 on the opposite side is a reflection electrode, so that the light exit surface structure layer 110 side is directed. An organic EL element that emits light from the light emitting surface 144 can be obtained. Further, both electrodes 141 and 143 are transparent electrodes, and further, a light emitting surface is provided by having a reflecting member or a scattering member (for example, a white scattering member disposed via an air layer) on the side opposite to the light emitting surface structure layer 110. Light emission to the surface structure layer 110 side can also be achieved.

  In addition to the light emitting layer 142, the organic EL element 140 further includes other layers (not shown) such as a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer between the electrode 141 and the electrode 143. May further be included. Further, the organic EL element 140 may further include arbitrary components such as a wiring for energizing the electrodes 141 and 143 and a peripheral structure for sealing the light emitting layer 142.

Although it does not specifically limit as a material which comprises an electrode and the layer provided among them, The following can be mentioned as a specific example.
Examples of the material for the transparent electrode include ITO (indium tin oxide).
Examples of the material for the hole injection layer include a starburst aromatic diamine compound.
Examples of the material for the hole transport layer include a triphenyldiamine derivative.
Examples of the host material for the yellow light emitting layer include triphenyldiamine derivatives, and examples of the dopant material for the yellow light emitting layer include tetracene derivatives.
Examples of the material for the green light emitting layer include pyrazoline derivatives.
Examples of the host material for the blue light emitting layer include anthracene derivatives, and examples of the dopant material for the blue light emitting layer include perylene derivatives.
Examples of the material for the red light emitting layer include a europium complex.
Examples of the material for the electron transport layer include aluminum quinoline complex (Alq).
Examples of the material for the reflective electrode include lithium fluoride and aluminum, which are sequentially laminated by vacuum film formation.

  By appropriately combining the above or other light-emitting layers, a light-emitting layer that generates a light emission color having a complementary color relationship, which is referred to as a stacked type or a tandem type, can be obtained. Thereby, it can be set as the light emitting layer which light-emits the light of the color of white or it. The combination of complementary colors can be yellow / blue, green / blue / red, or the like.

[1-3. (Phaser, Polarizer)
The organic EL display device 10 of the present embodiment includes a phase shifter 130 and a polarizer 120 between the organic EL element 140 and the light exit surface structure layer 110, and the phase shifter 130 and the polarizer 120 are arranged from the organic EL element side. It is composed in the order. With such a configuration, only linearly polarized light that matches the polarization axis of the polarizer is transmitted through the light that enters the organic EL display device from outside light. This linearly polarized light becomes circularly polarized light when passing through the phase shifter and enters the organic EL element, but when reflected by the reflective electrode, the direction of rotation is reversed to become reverse circularly polarized light, and passes through the phase shifter again. Since the linearly polarized light after passing through the phase shifter does not coincide with the polarization axis of the polarizer, it can be absorbed by the polarizer and not affected by external light.

(Polarizer)
The polarizer used in this embodiment is a linear polarizer, and as the polarizer used, for example, iodine or dichroic dye is adsorbed on a polyvinyl alcohol film and then uniaxially stretched in a boric acid bath. List polarizers such as those obtained or obtained by adsorbing or stretching iodine or a dichroic dye on a polyvinyl alcohol film and further modifying a part of the polyvinyl alcohol unit in the molecular chain to a polyvinylene unit. Can do. The polarization degree of the polarizer is preferably 98% or more, more preferably 99% or more. The thickness (average thickness) of the polarizer is preferably 5 μm to 80 μm. In addition, a protective film may be provided on at least one surface of the polarizer.

(Phaser)
As an example of the retarder used in the present embodiment, there is a ¼ wavelength plate. For example, a stretched film formed by stretching a film-like polymer can be used. As the polymer, a transparent resin can be preferably used. Examples thereof include polymethyl methacrylate, polystyrene, polycarbonate, polyether sulfone, amorphous polyethylene, triacetyl cellulose, and resins having an alicyclic structure. In addition, these may be used individually by 1 type and may be used combining two or more types by arbitrary ratios. Preferable examples include a quarter wavelength plate formed by stretching a resin film including a styrene resin layer, a quarter wavelength plate formed by stretching a resin film having an alicyclic structure, and the like.

    The retardation Re in the front direction of the quarter-wave plate (hereinafter sometimes referred to as “Re” as appropriate) is approximately a quarter wavelength of transmitted light. The retardation Re in the front direction is approximately ¼ wavelength of transmitted light. The Re value is ± 65 nm from the ¼ wavelength value of the center value in the center value of the wavelength range of transmitted light, preferably Means ± 30 nm, more preferably ± 10 nm. Since the polarization conversion function can be exhibited by having such a retardation value, the linearly polarized light emitted from the display device can be converted into circularly polarized light by the quarter wavelength plate. The quarter wavelength plate and the polarizer are preferably laminated so that the slow axis of the quarter wavelength plate and the absorption axis of the polarizer are 45 ° or 135 °.

[1-4. Other layers]
In the present invention, a support substrate may be provided between the phase retarder, the polarizer and the organic EL element. As an example of the material constituting the support substrate, a transparent material is usually used. Examples of the material include glass and resin. In addition, the material of a support substrate may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios. In the present invention, the transparent material can be a material having a total light transmittance of 80% or more when a member such as a support substrate is formed. The refractive index of the material constituting the support substrate is not particularly limited, but is preferably 1.4 to 2.0. Although the thickness of a support substrate is not specifically limited, It is preferable that it is 0.1 mm-5 mm.

  The organic EL display device 10 of the present embodiment may include an adhesive layer between each layer. The adhesive that is the material of the adhesive layer is not only a narrowly-defined adhesive (a so-called hot-melt adhesive having a shear storage modulus of 1 to 500 MPa at 23 ° C. and does not exhibit tackiness at room temperature). A pressure-sensitive adhesive having a shear storage modulus at 1 ° C. of less than 1 MPa is also included. More specifically, a transparent material having a refractive index close to that of each layer can be used as appropriate. More specifically, an acrylic adhesive or a pressure-sensitive adhesive can be used. The thickness of the adhesive layer is preferably 5 μm to 100 μm.

  The organic EL display device 10 of the present embodiment may include a sealing substrate. The sealing substrate may be provided so as to be in direct contact with the outside of the electrode 143 on the surface opposite to the light emitting surface 144 of the organic EL element. Further, an arbitrary substance such as a filler or an adhesive may be present between the electrode 143 and the sealing substrate, or a void may be present. As long as there is no inconvenience such as greatly impairing the durability of the light emitting layer 142, air or other gas may be present in the space, or the space may be evacuated. As the sealing substrate, any member capable of sealing the organic EL element 140 can be used. For example, the same member as the above-mentioned support substrate can be used.

  In the organic EL display device of this embodiment, a color filter may be provided between the organic EL light emitting element and the phase shifter. The color filter includes a red filter R that splits red, a green filter G that splits green, and a blue filter B that splits blue into blue. The transparent electrode and the reflective electrode may be formed to correspond to the pixels of each color. it can. The uneven structure layer in that case may be changed in shape according to each pixel. In particular, when the concavo-convex structure layer is changed for each color and arranged on the viewing side of the polarizer, the light distribution is not similar to Lambertian, and the concavo-convex is preferentially corresponding to at least one or two color pixels. A structural layer is preferably formed. By adopting such a configuration, it is possible to efficiently suppress color unevenness. On the other hand, when the concavo-convex structure layer is changed for each color and disposed between the polarizer and the organic EL light emitting element, the light is not condensed more in front from the viewpoint of increasing the front luminance or the extraction efficiency while suppressing color unevenness. It is preferable that the concavo-convex structure layer is preferentially formed corresponding to the pixels of the light distribution color.

[1-4. Production method〕
Although the manufacturing method of the organic EL display device 10 is not particularly limited, for example, the step of laminating each layer constituting the organic EL element 140 on the phase retarder side of the laminate of the phase retarder 130 and the polarizer 120, and the uneven structure layer 111 And a step of preparing the light exit surface structure layer 110 having the base film layer 112 and a step of attaching the prepared light exit surface structure layer 110 to the polarizer side of the laminate of the phase shifter 130 and the polarizer 120. Can be manufactured. The steps are not limited in order as long as the desired organic EL display device 10 is obtained.

The light-emitting surface structure layer 110 having the concavo-convex structure layer 111 and the base film layer 112 is manufactured by, for example, preparing a mold such as a mold having a desired shape, and using this mold as a layer for forming the concavo-convex structure layer 111. It can be performed by transferring to As a more specific method,
(Method 1) Unprocessed light-emitting surface structure layer having a layer of the resin composition A constituting the base film layer 112 and a layer of the resin composition B constituting the uneven structure layer 111 (an uneven structure has not yet been formed) And a method of forming an uneven structure on the surface of the raw light-emitting surface structure layer on the resin composition B side; and (Method 2) On the base film layer 112, the resin composition B in a liquid state And a method of forming the concavo-convex structure layer 111 by applying a mold to the applied layer of the resin composition B and curing the resin composition B in that state.

In Method 1, the raw light-emitting surface structure layer can be obtained by, for example, extrusion molding in which the resin composition A and the resin composition B are coextruded. An uneven structure can be formed by pressing a mold having a desired surface shape onto the surface of the raw light-emitting surface structure layer on the resin composition B side.
More specifically, a long unprocessed light-emitting surface structure layer is continuously formed by extrusion, and the unprocessed light-emitting surface structure layer is pressed with a transfer roll and a nip roll having a desired surface shape, thereby Continuous production can be performed efficiently. The pinching pressure between the transfer roll and the nip roll is preferably several MPa to several tens of MPa. The temperature at the time of transfer is preferably Tg or more (Tg + 100 ° C.) or less, where Tg is the glass transition temperature of the resin composition B. The contact time between the unprocessed light exit surface structure layer and the transfer roll can be adjusted by the film feed speed, that is, the roll rotation speed, and is preferably 5 seconds or more and 600 seconds or less.

  In Method 2, as the resin composition B constituting the concavo-convex structure layer 111, it is preferable to use a composition that can be cured by energy rays such as ultraviolet rays. The resin composition B is applied on the base film layer 112 and in a state where the mold is applied, the resin composition B is positioned on the back side of the application surface (the side opposite to the surface on which the resin composition B is applied). By irradiating energy rays such as ultraviolet rays from a light source to cure the resin composition B, and then peeling off the mold, the coating film of the resin composition B is used as the concavo-convex structure layer 111 to obtain the light exit surface structure layer 110. be able to.

[1-5. (Description of main advantages)
Since the organic EL display device 10 of the present embodiment is configured as described above, the light emitted from the light emitting surface 144 of the organic EL element 140 passes through the light emitting surface structure layer 110 and exits from the light emitting surface 10U. At this time, since the light exit surface 10U has a concavo-convex structure including the flat surface portions 113 and 114 and the slope portion 115, light can be extracted from the light exit surface 10U with high efficiency. Further, the shape of the light-emitting surface structure layer is characteristic, and there is little color unevenness, blurring, and distortion in a display object (characters, etc.) and excellent visibility.

[2. Second embodiment]
In the first embodiment, a concave portion is provided on the light output surface, and the concave-convex structure having the flat surface portion and the slope portion is configured by the concave portion. However, for example, a convex portion may be provided instead of the concave portion. Hereinafter, the example is demonstrated using drawing.

   6 to 9 are views for explaining an organic EL display device according to the second embodiment of the present invention. FIG. 6 is a perspective view schematically showing an organic EL display device. FIG. 7 is a cross-sectional view schematically showing a cross section of the organic EL display device shown in FIG. 6 cut along a plane that passes through the line 6a-6b and is perpendicular to the surface direction of the light exit surface. FIG. 8 is a partial plan view schematically showing an enlarged view of a part of the light emission surface of the organic EL display device as viewed from the thickness direction of the organic EL display device. FIG. 9 is a partial cross-sectional view schematically showing a cross section of the concavo-convex structure layer taken along a plane that passes through the line 8a of FIG. 8 and is perpendicular to the light exit surface.

  As shown in FIGS. 6 to 9, the organic EL display device 20 according to the second embodiment of the present invention is the same as that of the first embodiment except that the uneven structure layer 211 is provided instead of the uneven structure layer 111. This is the same as the organic EL display device 10. That is, the organic EL display device 20 according to the second embodiment has the same configuration as that of the first embodiment except that the shape of the light exit surface 20U that is the surface of the uneven structure layer 211 is different in the light exit surface structure layer 210. doing.

  The uneven structure of the light exit surface 20U is a shape obtained by inverting the unevenness of the uneven structure of the light exit surface 10U according to the first embodiment, and the flat surface portion 213, the flat surface portion 214, and the inclined surface portion 215 are the same as in the first embodiment. These correspond to the flat surface portion 113, the flat surface portion 114, and the slope portion 115, respectively. For this reason, the light exit surface 20U has a convex portion 216 instead of the concave portion 116, and the convex portion 216 has a shape obtained by cutting the top of a regular quadrangular pyramid parallel to the bottom surface. In addition, each of the convex portions 216 has a flat surface portion 214 parallel to the light emitting surface 144 as an upper surface, and has an inclined surface portion 215 inclined with respect to the flat surface portion 214 as a side surface. Further, a gap is provided between adjacent recesses 216, and this gap constitutes a flat surface portion 213 parallel to the light emitting surface 144.

  Therefore, also on the light exit surface 20U of the present embodiment, the projected area of the inclined surface portion 215 is usually 0.1 times or less the total area of the flat surface portions 213 and 214, as in the first embodiment. In addition, the maximum value of the height difference H between the flat surface portions 213 and 214 in the uneven structure of the light exit surface 20U is 12 μm or less, and the inclined surface portion 215 has an inclination angle θ of 45 ° or more and less than 90 ° with respect to the flat surface portions 213 and 214. Inclined. In FIG. 9, reference numeral “218” represents a repeating unit including the flat surface portion 213, the inclined surface portion 215, the flat surface portion 214, and the inclined surface portion 215.

  Since the organic EL display device 20 of the present embodiment is configured as described above, light emitted from the light emitting surface 144 of the organic EL element 140 is emitted from the light emitting surface 20U, and light emitted from the light emitting surface 145 is emitted from the light emitting surface. It will emit light from 10D. At this time, light can be extracted with high efficiency. Further, the same effects as in the first embodiment can be achieved.

[3. Third Embodiment]
In the first to second embodiments, the concave portions and the convex portions and the slope portions included in the concave portions or the convex portions are arranged along two directions that are parallel to the light output surface and orthogonal to each other. May be arranged along two non-orthogonal directions, may be arranged along three or more directions, or may be arranged randomly. Hereinafter, the example is demonstrated using drawing.

  10 and 11 are diagrams for explaining the organic EL display device according to the third embodiment of the present invention, and FIG. 10 schematically shows the state of the organic EL display device viewed from the thickness direction. 11 is a top view, and FIG. 11 is a cross-sectional view showing a cross section of the organic EL display device shown in FIG. 10 cut along a plane that passes through the line 10a in FIG. 10 and is perpendicular to the light exit surface 30U.

  As shown in FIGS. 10 and 11, the organic EL display device 30 according to the third embodiment of the present invention is the same as that of the first embodiment except that the uneven structure layer 311 is provided instead of the uneven structure layer 111. This is the same as the organic EL display device 10. That is, the organic EL display device 30 according to the third embodiment has the same configuration as that of the first embodiment except that the shape of the light exit surface 30U that is the surface of the uneven structure layer 311 constituting the light exit surface structure layer 310 is different. Have.

  A plurality of concave portions 316 having a shape (conical truncated cone shape) obtained by cutting the top of the cone parallel to the bottom surface is formed on the light exit surface 30U that is the surface of the uneven structure layer 311. Since it has a truncated cone shape, the concave portion 316 has a flat surface portion 314 parallel to the light emitting surface 144 as a bottom surface and an inclined surface portion 315 inclined with respect to the flat surface portion 314 as a side surface. Further, on the light exit surface 30U, the recesses 316 are continuously arranged along three in-plane directions parallel to the lines 10a, 10b, and 10c at a constant interval. Here, the lines 10a, 10b and 10c are at an angle of 60 ° to each other. Accordingly, a gap is provided between the adjacent recesses 313 along the lines 10 a, 10 b, and 10 c, and this gap constitutes a flat surface portion 313 that is parallel to the light emitting surface 144.

  Further, also on the light exit surface 30U of the present embodiment, the projected area of the inclined surface portion 315 is usually 0.1 times or less the total area of the flat surface portions 313 and 314, as in the first embodiment. In addition, the maximum height difference between the flat surface portions 313 and 314 in the uneven structure of the light exit surface 30U is 12 μm or less, and the inclined surface portion 315 is inclined with respect to the flat surface portions 313 and 314 at an inclination angle of 45 ° or more and less than 90 °. ing.

  Since the organic EL display device 30 of the present embodiment is configured as described above, light emitted from the light emitting surface 144 of the organic EL element 140 is emitted from the light emitting surface 30U, and light can be extracted with high efficiency. Further, the same effects as in the first embodiment can be achieved.

[4. Fourth Embodiment]
In the first to third embodiments, the dimensions of the recesses or protrusions formed on the same light exit surface are made constant, and the dimensions of the flat surface part and the slope part of the uneven structure are also made constant, but the dimensions are not uniform. Thus, a dimensional difference may be provided. In particular, if a dimensional difference exceeding the difference that causes interference between one or both of the outgoing light emitted from the outgoing surface and the reflected light reflected by the outgoing surface is provided, rainbow unevenness due to the interference of one or both of the outgoing light and reflected light is provided. Can be suppressed. For example, it is preferable that the difference in height of the flat surface portion corresponding to the depth or height of the concave portion or the convex portion has the dimensional difference. Hereinafter, examples of such an uneven structure will be described with reference to the drawings.

  FIG. 12 is a cross-sectional view schematically showing a cross section of the concavo-convex structure layer according to the fourth embodiment of the present invention. As shown in FIG. 12, the light exit surface 40U that is the surface of the concavo-convex structure layer 411 according to the fourth embodiment of the present invention includes a concave portion 416 having a flat surface portion 414 as a bottom surface and a slope portion 415 as a side surface, and a flat surface portion 417. A plurality of concave portions 419 having a bottom surface as a bottom surface and a slope portion 418 as a side surface are provided. Further, a gap is provided between the recesses 416 and 419, and this gap constitutes a flat surface portion 413.

  In the light exit surface 40U of the present embodiment, the projected areas of the slope portions 415 and 418 are usually 0.1 times or less the total area of the flat surface portions 413, 414 and 417, as in the first embodiment. Further, the maximum value of the height difference of the flat surface portions 413, 414 and 417 in the uneven structure of the light exit surface 40U is 12 μm or less, and the slope portions 415 and 418 are 45 ° or more and less than 90 ° with respect to the flat surface portions 413, 414 and 417. It is inclined at an inclination angle of.

  Here, the depth of the concave portion 416 (that is, the height difference between the flat surface portion 413 and the flat surface portion 414) H416 is smaller than the depth of the concave portion 419 (that is, the height difference between the flat surface portion 413 and the flat surface portion 417) H419. It has become. In this case, if there is a dimensional difference H419-H416 exceeding the difference between the depth H416 of the concave portion 416 and the depth H419 of the concave portion 419 that causes interference of one or both of the emitted light and the reflected light, the rainbow unevenness due to the interference. Can be suppressed. At this time, the dimensional difference H419-H416 may be a dimensional difference exceeding the difference that causes interference of the emitted light, but the reflected light tends to have a greater influence on the rainbow unevenness than the emitted light. It is preferable that the size difference exceeds a difference that causes interference of reflected light, and it is more preferable that the size difference exceeds a difference that causes interference of both outgoing light and reflected light. More specifically, when there is no dimensional difference described above, interference occurs between the light reflected by the flat surface portions 413, 414, and 417 on the upper surface of the uneven structure layer 411 and the light reflected by the lower surface of the uneven structure layer 411. And rainbow unevenness occurred. However, by providing the surface concavo-convex structure with the predetermined dimensional difference, interference between reflected lights can be suppressed, and rainbow unevenness on the light exit surface 40U can be suppressed.

  The dimensional difference exceeding the difference that causes the interference is, for example, interference of outgoing light emitted from the organic EL element 140, for example, usually 0.62 times or more of the center wavelength of outgoing light, preferably 1 Dimensional difference more than 5 times. By providing this dimensional difference, the occurrence of rainbow unevenness can be suppressed. The upper limit of the dimensional difference is not particularly limited, but is preferably 60 times or less of the center wavelength of the emitted light.

  The above numerical range is confirmed from the knowledge shown below. In other words, in a structural layer designed in such a manner that all the depths of the recesses are made uniform, if an error of 170 nm or more occurs in the depth of the recesses, interference occurs and rainbow unevenness appears. It has been found that the generation of rainbow unevenness can be suppressed by daringly providing a dimensional difference that is twice or more the minimum value. Further, in the structure layer designed in such a manner that all the depths of the recesses are made uniform, if a variation of σ1 nm (≈60 nm) with a standard deviation occurs in the depth of the recesses, interference occurs and rainbow unevenness appears. = 360 nm) It is known that the generation of rainbow unevenness can be suppressed by intentionally providing a dimensional difference of not less than 360 nm. Based on the above two findings, it can be shown that the dimensional difference exceeding the difference that causes interference of the emitted light is 0.62 or more times the center wavelength of the light emitted from the organic EL display device.

  For the same reason, in the interference between transmitted light and reflected light, the dimensional difference exceeding the difference that causes interference is usually 0.62 times or more, preferably 1.5 times or more the center wavelength of transmitted light and reflected light. And a dimensional difference of usually 60 times or less. However, normally, since transmitted light and reflected light are natural light and include light having an arbitrary wavelength, it is difficult to determine the center wavelength of the reflected light. Therefore, in view of the fact that the light that causes rainbow unevenness is visible light, the above-mentioned dimensional difference may be set as the center wavelength of light that normally reflects the center wavelength of visible light of 550 nm.

  Furthermore, even when the concavo-convex structure has a dimensional difference as in this embodiment, light can be extracted with high efficiency, and further, the same effect as in the first embodiment can be obtained.

  The same effect can be obtained even when the above-described dimensional difference is provided in the elements other than the height difference of the flat surface portion. For example, if there is a dimensional difference in one or more elements of the group of elements such as the difference in level of the flat surface portion, the interval between the concave or convex portions, the pitch of the repetitive structure, the rainbow unevenness can be similarly suppressed. .

[5. Fifth embodiment]
In the first embodiment, the light exit surface structure layer 110 is disposed on the light exit surface side of the polarizer 120. However, the light exit surface structure layer 110 is disposed on the light exit surface side of the organic EL element directly or via a layer such as a sealing layer or an adhesive layer. May be. Hereinafter, the example is demonstrated using drawing.

  FIG. 13: is sectional drawing which showed typically the cross section explaining the organic electroluminescent display apparatus 50 which concerns on 5th embodiment of this invention. As shown in FIG. 13, the light emitting surface structure layer 510 is laminated on the light emitting surface side of the organic EL element 140, and the organic EL element 140, the light emitting surface structure layer 510, the phase shifter 130, and the polarizer 120 are in this order. Is the same as in the first embodiment. With such a configuration, the light extraction efficiency of the organic EL element can be further improved. The bonding between the structural layer 511 and the phase shifter 130 is not particularly limited, but a material that does not impair visibility (specifically, an olefin-based adhesive layer such as an acrylic-based material, or various photosensitive resins such as acrylates and methacrylates). Used) and a thick adhesive layer 520. Even with such a configuration, the same effect as the first embodiment can be obtained, and the light extraction effect can be improved. In order to further improve the light extraction efficiency, a configuration in which the refractive index decreases from the light emitting layer toward the light emitting surface structure layer is preferable.

[6. Sixth embodiment]
In 1st embodiment, although it was the structure provided with the phase retarder 130, the polarizer 120, and the light emission surface structure layer 110 in one surface of this organic EL element, the polarizer 120 and the light emission surface structure Further, a retardation film (¼ wavelength plate) 160 may be provided between the layer 110 and the layer 110. FIG. 14 is a cross-sectional view schematically showing an organic EL display device 60 corresponding to this implementation.
With this configuration, the light emitted from the light exit surface becomes circularly polarized light. The reason for further providing a retardation film (quarter wave plate) is, for example, for a display for 3D stereoscopic display. When viewing 3D stereoscopic video through polarized glasses, the display is affected even if the viewer tilts his / her head. There is an advantage that there is no.

  Further, in consideration of the second embodiment, as shown in FIG. 15, the light emitting surface structure layer 310 is laminated on the light emitting surface side of the organic EL element 140, and the organic EL element 140, the light emitting surface structure layer 310, the phaser 130, A configuration in which the polarizer 120 and the retardation film 160 are in this order can also be considered. The relationship between the slow axes of the two retardation films may be orthogonal or parallel.

[7. Others]
Although the embodiment of the organic EL display device of the present invention has been described, the present invention may be further modified.
For example, in the above-described embodiment, the polarizer or the light exit surface structure layer is provided so as to be in direct contact with the light emission surface, but the light exit surface structure layer may be provided on the light emission surface via another layer. Examples of the other layer include a gas barrier layer that protects the organic EL element from the outside air and moisture, and an ultraviolet cut layer that blocks ultraviolet rays.

  In addition, for example, in the above-described embodiment, the light exit surface structure layer is composed of a concavo-convex structure layer and a base film layer. However, the light exit surface structure layer is composed of layers smaller than these. Alternatively, on the contrary, an optional layer may be further included in addition to these layers. For example, a coating layer may be further provided on the surface of the concavo-convex structure layer, and this may define the concavo-convex structure on the light exit surface.

Further, for example, the position, orientation, shape, number, and combination of the flat surface portion and the slope portion are not limited to those in the embodiment, and may be changed.
As a specific example, the flat surface portion may be provided in one step as shown in FIG. 16 in addition to providing the height position in two steps as in the above-described embodiment. FIG. 16 is a cross-sectional view schematically showing a cross section of the concavo-convex structure layer according to the embodiment of the present invention. In the concavo-convex structure layer 811 shown in FIG. 16, a slope portion 815 is provided as a side surface of the conical recess 816, and a flat surface portion 813 is provided with the height position aligned in the gap between the adjacent recesses 816. In this way, even when the height position of the flat surface portion is aligned in one step, the flat surface portion 813 and the inclined surface portion 815 are formed by keeping the projected area of the inclined surface portion 815 within a predetermined range with respect to the area of the flat surface portion 813. Light can be extracted with high efficiency from the exit surface 80U.

  Also, for example, as shown in FIG. 17, the height position of the flat surface portion may be arranged in three or more stages. FIG. 17 is a cross-sectional view schematically showing a cross section of a concavo-convex structure layer according to another embodiment of the present invention. In the concavo-convex structure layer 911 shown in FIG. 17, the concave portion 916 includes flat surface portions 914 and 917 and inclined surface portions 915 and 918. Further, as a bottom surface, a slope portion 915 is provided around the flat surface portion 914, a flat surface portion 917 is provided around the slope portion 915, a slope portion 918 is provided around the flat surface portion 9917, and a gap between adjacent recesses 916 is provided. Is provided with a flat surface portion 913. Thus, even when the height position of the flat surface portion is aligned in a plurality of steps of three or more steps, the projected area of the slope portions 915 and 918 is kept within a predetermined range with respect to the total area of the flat surface portions 913, 914 and 917. The light can be extracted with high efficiency from the light exit surface 900U having the flat surface portions 913, 914 and 917 and the slope portions 915 and 918. In addition, when aligning the height position of a flat surface part in multiple steps | paragraphs of 3 steps or more, the maximum value of the height difference of the flat surface part of a thickness direction becomes a dimension shown with the code | symbol HMAX in FIG.

  Further, in addition to making the slope portion a flat plane as in the above-described embodiment, it may be a curved surface as shown in FIG. FIG. 18 is a cross-sectional view schematically showing a cross section of a structural layer according to another embodiment of the present invention. In the concavo-convex structure layer 1011 shown in FIG. 18, a flat surface portion 1014 is provided as the bottom surface of the concave portion 1016, and has a curved surface shape in which the inclination angle gradually increases or decreases as the distance from the flat surface portion 1014 increases around the flat surface portion 1014. A slope portion 1015 is provided, and a flat surface portion 1013 is provided around the slope portion 1015. Thus, even when the slope portion is a curved surface, the flat surface portions 1013 and 1014 and the slope portion can be obtained by keeping the projected area of the slope portion 1015 within a predetermined range with respect to the total area of the flat surface portions 1013 and 1014. Light can be extracted with high efficiency from the light exit surface 1000U having 1015.

  Therefore, the shape of the concave and convex portions formed on the light exit surface can have various shapes such as a truncated pyramid shape, a truncated cone shape, a partial spherical shape, and a combination thereof. In addition, the shape of the bottom surface of the truncated pyramid shape may be a triangle, pentagon, hexagon, quadrangle other than a square, or the like.

  Further, in the above-described embodiment, the concave portions or the convex portions distributed over the entire surface of the light exit surface are shown as those having only the same shape distributed, but the light exit surface has different concave portions or convex portions. May be mixed, and a recessed part and a convex part may be mixed. For example, concave portions or convex portions having different sizes may be mixed, concave and convex portions having a truncated pyramid shape and a truncated cone shape may be mixed, or inclined portions having different inclination angles may be mixed.

  In addition, for example, in the above-described embodiment, the width of the concave portion and the convex portion, and the interval between the adjacent concave portions and the interval between the convex portions are constant, but the width of the concave portion and the convex portion is narrow. A thing and a wide thing may be mixed, and the space | interval of adjacent recessed parts and the location where the space | interval of convex parts is narrow, and a wide location may be mixed.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the examples shown below, and may be arbitrarily changed without departing from the gist of the present invention and its equivalent scope. May be implemented.

[Example 1]
(Manufacture of light-emitting surface uneven structure layer 1)
UV curing based on urethane acrylate on roll film substrate (trade name “ZEONOR FILM”, manufactured by Nippon Zeon Co., Ltd., alicyclic structure-containing polymer resin film, thickness 100 μm, refractive index 1.53) A resin (refractive index of 1.54) was applied to form a coating film, and a metal mold was pressed onto the coating film. In this state, ultraviolet rays were irradiated at 1.5 mJ / cm ² to cure the coating film, and an uneven structure layer (thickness 12 μm) having an uneven structure was formed. The metal mold for creating the concavo-convex structure uses a cutting tool 1 having an apex angle of 15 ° and a tip width of 5 μm to place the repeating unit shown in FIG. And then cut along a direction perpendicular to the direction. Cutting was performed at a constant cutting pitch P. Moreover, the depth of the groove | channel formed by cutting was changed into five steps of H1-H5, and it cut repeatedly using the five groove | channels formed in this way as a repeating unit. In the present embodiment, the cutting pitch P is set to 35 μm, and the depths H1 to H5 of the grooves included in the repeating unit are 6.4 μm for H1, 6.7 μm for H2, 7 μm for H3, 7.3 μm for H4, and H5 was set to 7.6 μm. The widths W1 to W5 of the five grooves thus formed were 6.69 μm for W1, 6.76 μm for W2, 6.84 μm for W3, 6.92 μm for W4, and 7.00 μm for W5. .

  FIG. 20 is a diagram schematically showing a cross section of the concavo-convex structure layer obtained in Example 1 cut along a plane perpendicular to the cutting direction. As shown in FIG. 20, the surface of the resulting concavo-convex structure layer 3 is formed with a concavo-convex structure having a number of quadrangular pyramid-shaped concave portions corresponding to the grooves formed in the metal mold, and around the concave portions. A plurality of flat surfaces having different height positions and pitches were provided. On the surface of the concavo-convex structure layer 3 on which the concavo-convex structure was formed, the average inclination angle of the inclined portion with respect to the flat surface portion was 82.5 °. The ratio of the projected area of the slope portion to the total area (total area) of the flat surface portion was 0.1, and the maximum height difference of the flat surface portion was 7.6 μm. In addition, the average value of the length of the base of the quadrangular frustum-shaped concave portion was 30 μm, and the average value of the depth was 7 μm.

(Manufacture of organic EL display device 1)
On the light emitting surface of GALAXY S II SC-02C (manufactured by Samsung Electronics Co., Ltd.), an organic EL display, a quarter wave plate (manufactured by Zeon Corporation, product name “obliquely stretched ZEONOR film”), polarizing plate (manufactured by Sanlitz, product Name “HLC2-5618S”, thickness 180 μm), and light emitting surface uneven structure layer 1 in this order such that the transmission axis of the polarizing plate and the slow axis of the quarter-wave plate are 45 °. (Acrylic resin, refractive index 1.49, manufactured by Nitto Denko Corporation, CS9621), and an organic EL display device having a layer structure of transparent organic EL display-adhesive layer-film substrate-light emitting surface structure layer 1 was obtained.
The obtained organic EL display device 1 was energized to emit light, and the visibility of the organic EL display device 1 was visually confirmed. It was clearly visible with no blurring or distortion of letters, and had excellent visibility.

[Example 2]
(Manufacture and evaluation of organic EL display device 2)
A light emitting surface structure layer was prepared in the same manner as in Example 1 except that the uneven structure layer was prepared so that the ratio of the projected area of the slope portion to the total area (total area) of the flat surface portion of the uneven structure layer was 0.5. In the same manner as in Example 1, an organic EL display device 2 was produced.
The obtained organic EL display device 2 was energized to emit light, and the visibility of the organic EL display device 2 was visually confirmed. The characters were clearly visible with no blurring or distortion, and visibility was excellent.

Example 3
(Manufacture and evaluation of organic EL display device 3)
A light emitting surface structure layer was prepared in the same manner as in Example 1 except that the uneven structure layer was prepared so that the ratio of the projected area of the slope portion to the total area (total area) of the flat surface portion of the uneven structure layer was 1.0. In the same manner as in Example 1, an organic EL display device 3 was prepared.
The obtained organic EL display device 3 was energized to emit light, and the visibility of the organic EL display device 3 was visually confirmed. Although there was blurring and distortion of the characters, the characters could be read.

[Comparative Example 1]
(Manufacture and evaluation of organic EL display device 4)
A light emitting surface structure layer was prepared in the same manner as in Example 1 except that the uneven structure layer was prepared so that the ratio of the projected area of the slope portion to the total area (total area) of the flat surface portion of the uneven structure layer was 1.5. In the same manner as in Example 1, an organic EL display device 4 was produced.
The obtained organic EL display device 4 was energized to emit light, and the visibility of the organic EL display device 3 was visually confirmed. Characters were blurred or distorted and the characters were unclear.

  The organic EL display device of the present invention can extract light with high efficiency and has excellent visibility without blurring, distortion, color unevenness, or the like in the display image.

DESCRIPTION OF SYMBOLS 10 Organic EL display apparatus 10U Light emission surface 110 Light emission surface structure layer 111 Uneven structure layer 112 Base film layer 113 Flat surface part 114 Flat surface part 115 Slope part 116 Recessed part 117 Boundary line between the slope part 115 and the flat surface part 118 Repetitive unit 120 Polarization Child 130 phaser 140 organic EL element 141 transparent electrode layer 142 light emitting layer 143 reflective electrode layer 144 light emitting surface 160 retardation film 20 organic EL display device 20U light emitting surface 210 light emitting surface structural layer 211 uneven structure layer 213 flat surface portion 214 flat surface portion 215 Slope portion 216 Convex portion 218 Repeat unit 30 Organic EL display device 30U Light emission surface 310 Light emission surface structure layer 311 Concavity and convexity structure layer 313 Flat surface portion 314 Flat surface portion 315 Concavity portion 316 Concavity 40U Light emission surface 411 Concavity and convexity structure layer 413 Flat surface portion 414 Flat surface portion 415 Slope portion 416 Recessed portion 417 Flat surface portion 418 Slope portion 419 Recessed portion 50 Organic EL display device 510 Light emitting surface structure layer 511 Concavity and convexity structure layer 512 Base film layer 520 Adhesive layer 60 Organic EL display device 70 Organic EL display device 811 Uneven structure layer 813 Flat surface portion 815 Slope portion 816 Recessed surface 900U Light exit surface 900U Light exit surface 911 Uneven structure layer 913 Flat surface portion 914 Flat surface portion 915 Slope portion 916 Recess 917 Flat surface portion 918 Slope portion 1000U Uneven structure surface 1014 Uneven structure surface 1014 Surface 1015 Slope 1016 Recess

Claims (6)

A display device comprising an organic electroluminescence element and a phase shifter, a polarizer, and a light emission surface structure layer on the light emission surface side of the organic electroluminescence element,
The phaser and the polarizer are installed in the order of the phaser and the polarizer from the organic electroluminescence element side,
The light-emitting surface structure layer has an uneven surface having a flat surface portion parallel to one surface of the organic electroluminescence element and a slope portion inclined with respect to the flat portion on the surface opposite to the organic electroluminescence element. Has a structure,
A projected area formed by projecting the slope portion in a direction perpendicular to the flat surface portion onto a plane parallel to the flat surface portion is 1.0 times or less of the total area of the flat surface portions. An organic electroluminescence display device. Organic electroluminescence device, phase shifter, polarizer, light emitting surface structure layer in this order,
The organic electroluminescence display device according to claim 1, wherein the organic electroluminescence device is arranged in the order of an organic electroluminescence element, a light emitting surface structure layer, a phase shifter, and a polarizer.   The organic electroluminescence display device according to claim 1, further comprising a retardation film on a light exit surface side of the polarizer.   The organic electroluminescence display device according to any one of claims 1 to 3, wherein a maximum value of a height difference of the flat surface portion in the concavo-convex structure is 12 µm or less. The slope portion is inclined at an inclination angle of 45 ° or more and less than 90 ° with respect to the flat surface portion,
The organic electroluminescent display apparatus as described in any one of Claims 1-4.   The organic electroluminescence display device according to claim 1, wherein a difference in height of the flat surface portion is 0.1 μm or more.

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