Plane light-emitting device and display device

Abstract

To suppress decrease in light extraction efficiency without highly accurate alignment.SOLUTION: A plane light-emitting device 100 includes a light-emitting unit 110 including a plurality of light-emitting elements 112 disposed regularly on a light-emitting surface 110a, a protection layer 120 stacked on the light-emitting unit 110, a lens layer 130 stacked on the protection layer 120 and having a plurality of microlenses 160 with a convex or concave shape formed inside, and a base material layer 170 stacked on the lens layer 130. The microlenses 160 are disposed irregularly on an XY plane that is parallel to the light-emitting surface 110a. The microlenses 160 are disposed irregularly on the XY plane so that when the light-emitting elements 112 and the microlenses 160 are projected onto the XY plane, at least four or more microlenses 160 overlap at least partially.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a surface-emitting device and a display device. [Background technology]

[0002] In order to change the diffusion characteristics of light, a diffuser plate that diffuses incident light in a desired direction is used. Diffuser plates are widely used in various devices, such as display devices such as displays, projection devices such as projectors, and various lighting devices. There is a type of diffuser plate that diffuses incident light at a desired diffusion angle by utilizing the refraction of light caused by the surface shape of the diffuser plate. As a diffuser plate of this type, a microlens array type diffuser plate in which a plurality of microlenses having a size of about several tens of μm are arranged is known.

[0003] For example, Patent Document 1 discloses a configuration in which a convex microlens is arranged for each subpixel in order to improve the efficiency of extracting light from a light emitting device (hereinafter referred to as "light extraction efficiency"). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-216454 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology of Patent Document 1 has a problem that the light extraction efficiency decreases when the relative positional relationship between the microlens and the subpixel deviates from the design value. Therefore, the technology of Patent Document 1 requires highly accurate alignment between the microlens and the subpixel, which causes a problem that the alignment work becomes complicated.

[0006] Therefore, the present invention has been made in consideration of the above problems, and an object of the present invention is to provide a surface-emitting device and a display device that are capable of suppressing a decrease in light extraction efficiency without the need for highly accurate alignment. [Means for solving the problem]

[0007] In order to solve the above problems, according to one aspect of the present invention, a light-emitting section having a plurality of light-emitting elements regularly arranged on a light-emitting surface; A protective layer laminated on the light-emitting portion; a lens layer laminated on the protective layer and having a plurality of convex or concave microlenses formed therein; A substrate layer laminated on the lens layer; Equipped with the plurality of microlenses are irregularly arranged on an XY plane parallel to the light emitting surface, A surface-emitting device is provided in which the multiple microlenses are irregularly arranged on the XY plane such that when the multiple light-emitting elements and the multiple microlenses are projected onto the XY plane, at least a portion of at least four or more of the microlenses overlaps with one light-emitting element.

[0008] The light emitting element has a rectangular planar shape, The diameter of an inscribed circle inscribed in the aperture shape of each of the microlenses may be 55% or less of the short side of the light emitting element.

[0009] The lens layer is a first lens layer having a concave-convex structure formed of the plurality of microlenses on a surface thereof; a second lens layer covering the uneven structure of the surface of the first lens layer to flatten the uneven structure of the first lens layer; The above configuration may be adopted.

[0010] the second lens layer of the lens layer is laminated on the protective layer; the first lens layer of the lens layer is laminated on the second lens layer; the substrate layer is laminated on the first lens layer of the lens layer; the plurality of microlenses formed in the first lens layer are concave lenses recessed toward the base layer; The first lens layer may have a lower refractive index than the second lens layer.

[0011] the second lens layer of the lens layer is laminated on the protective layer; the first lens layer of the lens layer is laminated on the second lens layer; the substrate layer is laminated on the first lens layer of the lens layer; the plurality of microlenses formed in the first lens layer are convex lenses protruding toward the protective layer, The first lens layer may have a higher refractive index than the second lens layer.

[0012] the first lens layer of the lens layer is laminated on the protective layer; the second lens layer of the lens layer is laminated on the first lens layer; the substrate layer is laminated on the second lens layer of the lens layer; the plurality of microlenses formed in the first lens layer are convex lenses protruding toward the base layer; The first lens layer may have a higher refractive index than the second lens layer.

[0013] the first lens layer of the lens layer is laminated on the protective layer; the second lens layer of the lens layer is laminated on the first lens layer; the substrate layer is laminated on the second lens layer of the lens layer; the plurality of microlenses formed in the first lens layer are concave lenses recessed toward the protective layer, The first lens layer may have a lower refractive index than the second lens layer.

[0014] The lens layer may have a refractive index lower than that of the protective layer.

[0015] The refractive index of the base layer may be lower than the refractive index of the protective layer.

[0016] There may be no flat portion at the boundary between the adjacent microlenses.

[0017] The light emitting section, the protective layer, the lens layer, and the base layer may be directly laminated in this order.

[0018] The light emitting element may be an organic EL element.

[0019] In order to solve the above problems, according to one aspect of the present invention, There is provided a display device comprising the above-described surface-emitting device. Effect of the Invention

[0020] As described above, according to the present invention, it is possible to suppress a decrease in light extraction efficiency without high-precision alignment. [Brief description of the drawings]

[0021] [Figure 1] 1 is a cross-sectional view illustrating a schematic view of a surface-emitting device according to an embodiment of the present invention. [Diagram 2] FIG. 4 is a diagram illustrating the relationship between the refractive index of each layer and the light extraction efficiency. [Diagram 3] 11A to 11C are diagrams illustrating an effect of the microlens according to the embodiment. [Figure 4] 10A to 10C are diagrams illustrating another example of a microlens according to the embodiment. [Diagram 5] 3A and 3B are a plan view and an enlarged view showing a schematic view of a first lens layer according to the embodiment. [Figure 6]3A and 3B are an enlarged plan view and an enlarged cross-sectional view illustrating a schematic configuration of a first lens layer according to the embodiment. [Figure 7] 4 is an enlarged cross-sectional view showing a schematic view of the vicinity of a boundary of a microlens according to the embodiment; FIG. [Figure 8] 2 is a plan view that illustrates a schematic planar shape (outer shape) of a microlens when the microlens is viewed in a direction perpendicular to the surface of a base layer according to the embodiment. FIG. [Figure 9] 11 is a projection diagram showing the planar shapes of a plurality of light-emitting elements and a plurality of microlenses according to the embodiment when the light-emitting elements and a plurality of microlenses are projected onto an XY plane. FIG. [Figure 10] 13 is a flowchart showing a method for designing a microlens according to the embodiment. [Figure 11] 4 is a plan view showing the arrangement of lens center coordinates of the microlenses according to the embodiment. FIG. [Figure 12] 2 is a plan view showing an arrangement of microlenses having a rotationally symmetric aspheric shape according to the embodiment. FIG. [Figure 13] 3A and 3B are a plan view and a perspective view showing an arrangement of microlenses having a rotationally asymmetric aspheric shape according to the embodiment. [Figure 14] 11 is a perspective view showing a method for determining a reference aspheric shape of a microlens according to the embodiment. FIG. [Figure 15] 6 is a flowchart showing a method for manufacturing the surface emitting device according to the embodiment. [Figure 16] FIG. 11 is a process diagram showing step S117 according to the embodiment. [Figure 17] FIG. 11 is another process diagram showing S117 according to the embodiment. [Figure 18] 11 is a cross-sectional view illustrating another example of the surface-emitting device according to the embodiment. FIG. [Figure 19] 4 shows simulation results for Example 1 and the comparative example. [Figure 20] 4 shows simulation results for Example 2 and the comparative example. [Figure 21]4 shows the results of a simulation of the output efficiency of Examples 3 to 6. [Figure 22] 4 shows simulation results of front luminance in Examples 3 to 6. [Figure 23] 13 shows the results of a simulation of the output efficiency due to differences in sag in Examples 7 to 10. [Figure 24] 13 shows the results of a simulation of the emission efficiency due to differences in aspect ratio between Example 8 and Example 9. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same functional configurations are designated by the same reference numerals, and duplicated explanations will be omitted.

[0023] <1. Overview of surface-emitting devices> First, the overall configuration of a surface emitting device according to one embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view that typically shows a surface emitting device 100 according to this embodiment.

[0024] As shown in FIG. 1, the surface-emitting device 100 according to the present embodiment includes a light-emitting section 110, a protective layer 120, a lens layer 130, and a base layer 170. In the present embodiment, for example, the light-emitting section 110, the protective layer 120, the lens layer 130, and the base layer 170 are directly stacked in this order. However, the surface-emitting device 100 only needs to include the light-emitting section 110, the protective layer 120, the lens layer 130, and the base layer 170, and the stacking order of these layers in the surface-emitting device 100 is not limited. In addition, in the surface-emitting device 100, the light-emitting section 110, the protective layer 120, the lens layer 130, and the base layer 170 may not be directly stacked. For example, in addition to the light-emitting section 110, the protective layer 120, the lens layer 130, and the base layer 170, other layers may be stacked.

[0025] The light emitting unit 110 has a plurality of light emitting elements 112. The light emitting elements 112 constitute, for example, one subpixel. The light emitting elements 112 emit light of any one of red (R), green (G), and blue (B). The light emitting elements 112 may emit light of a wavelength other than "R", "G", and "B". For example, the light emitting elements 112 may emit white light. The plurality of light emitting elements 112 may emit light of different wavelengths from each other, or may emit light of the same wavelength from each other.

[0026] In this embodiment, one pixel (picture element) is composed of three light-emitting elements 112, for example, a light-emitting element 112 that emits "R" light, a light-emitting element 112 that emits "G" light, and a light-emitting element 112 that emits "B" light.

[0027] The light-emitting element 112 is, for example, an organic EL element. In this case, the light-emitting element 112 includes, for example, a cathode, an electron transport layer, a light-emitting layer, a hole transport layer, and an anode. The light-emitting layer of the light-emitting element 112 includes an organic EL material. The organic EL material may be a polymer organic material such as diamine, anthracene, or a metal complex, or a low-molecular organic material. The organic EL material is, for example, tris(8-quinolinate)aluminum (Alq3).

[0028] Alternatively, the light emitting element 112 may be an inorganic EL element. In this case, the light emitting layer of the light emitting element 112 includes an inorganic EL material. The inorganic EL material is, for example, gallium nitride.

[0029] Furthermore, the light emitting element 112 may include, in addition to the light emitting layer, either or both of a color filter and a cavity structure.

[0030] The light emitting element 112 has a planar shape. The light emitting element 112 has a polygonal shape such as a rectangular shape, a triangular shape, a hexagonal shape, or a circular shape. The multiple light emitting elements 112 may have the same shape or different shapes.

[0031] Furthermore, in the light-emitting section 110, the multiple light-emitting elements 112 are regularly arranged on the light-emitting surface 110a. The light-emitting surface 110a is a flat surface of the light-emitting section 110. In other words, the multiple light-emitting elements 112 (light-emitting layers) are regularly arranged to form a flat light-emitting surface 110a.

[0032] 1, the light-emitting surface 110a may be disposed on the protective layer 120 side. Alternatively, the light-emitting surface 110a may be disposed on the opposite side of the protective layer 120. In this case, the light-emitting element 112 may have a reflection mechanism that reflects light emitted from the light-emitting layer toward the protective layer 120 side.

[0033] The protective layer 120 is laminated on the light emitting section 110. The protective layer 120 is laminated, for example, on the light emitting surface 110a of the light emitting section 110. The protective layer 120 protects the light emitting section 110. The protective layer 120 is preferably composed of a dense structure. A dense structure is a structure in which crystal lattices are regularly arranged and there are few lattice defects or amorphous regions. The protective layer 120 is composed of, for example, silicon nitride (SiN) or silicon oxide (SiO2).

[0034] The lens layer 130 is laminated on the protective layer 120. A plurality of convex or concave microlenses 160 are formed inside the lens layer 130. In this embodiment, the lens layer 130 preferably includes a first lens layer 140 and a second lens layer 150.

[0035] A concave-convex structure made up of a plurality of microlenses 160 is formed on surface 142a of first lens layer 140. The plurality of microlenses 160 formed on first lens layer 140 are, for example, concave lenses recessed towards base layer 170 as shown in FIG.

[0036] Although details will be described later, in this embodiment, the multiple microlenses 160 are irregularly arranged on an XY plane parallel to the light emitting surface 110a. The first lens layer 140 is a microlens array.

[0037] The second lens layer 150 covers the uneven structure of the surface 142 a of the first lens layer 140 in order to flatten the uneven structure of the first lens layer 140 .

[0038] In the example shown in FIG. 1, in the lens layer 130, the second lens layer 150 is laminated on the protective layer 120, and the first lens layer 140 is laminated on the second lens layer 150.

[0039] The substrate layer 170 is laminated on the lens layer 130. In the example shown in FIG. 1, the substrate layer 170 is laminated on the first lens layer 140 of the lens layer 130. The substrate layer 170 protects the lens layer 130. The substrate layer 170 may be in the form of a film or a plate. The substrate layer 170 may be in the form of a flat plate or a curved plate. The substrate layer 170 shown in FIG. 1 has, for example, a rectangular flat plate shape, but is not limited to such an example. The shape and thickness of the substrate layer 170 may be any shape and thickness depending on the shape, configuration, etc. of the surface-emitting device 100.

[0040] First lens layer 140, second lens layer 150, and base layer 170 are formed of a transparent material capable of transmitting light. First lens layer 140, second lens layer 150, and base layer 170 are formed of a material that can be considered transparent in the wavelength band of light emitted from light emitting section 110. For example, first lens layer 140, second lens layer 150, and base layer 170 may be formed of a material having a light transmittance of 70% or more in the wavelength band of visible light.

[0041] First lens layer 140, second lens layer 150, and base layer 170 may be formed of known resins such as polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polycarbonate (PC), cycloolefin copolymer (COC), cycloolefin polymer (COP), triacetylcellulose (TAC), etc. Base layer 170 may be formed of known optical glass such as quartz glass, borosilicate glass, white plate glass, etc.

[0042] <2. Refractive index of each layer> Next, the refractive indexes of the light emitting section 110, the protective layer 120, and the lens layer 130 will be described with reference to FIGS. 2 to 4. FIG. 2 is a diagram for explaining the relationship between the refractive index of each layer and the light extraction efficiency. The upper diagram (FIG. 2A) in FIG. 2 shows a surface-emitting device 10 including only the light emitting section 110 and the protective layer 120. The center diagram (FIG. 2B) in FIG. 2 shows a surface-emitting device 20 including the light emitting section 110, the protective layer 120, the first layer 22, and the second layer 24. The lower diagram (FIG. 2C) in FIG. 2 shows a surface-emitting device 100 including the light emitting section 110, the protective layer 120, and the lens layer 130. Note that the base layer 170 is not shown in FIG. 2C. FIG. 3 is a diagram for explaining the effect of the microlens 160. The upper diagram (FIG. 3A) in FIG. 3 shows a case where the refractive index n3 of the first lens layer 140 is higher than the refractive index n2 of the second lens layer 150. The lower diagram in Fig. 3 (Fig. 3B) shows a case where the refractive index n3 of first lens layer 140 is lower than the refractive index n2 of second lens layer 150. Fig. 4 is a diagram for explaining another example of microlens 160. The upper diagram in Fig. 4 (Fig. 4A) is a cross-sectional view that typically shows another surface-emitting device 100 according to this embodiment. The lower diagram in Fig. 4 (Fig. 4B) shows a case where the refractive index n3 of first lens layer 140 is higher than the refractive index n2 of second lens layer 150. Also, in Figs. 2 to 4, dashed arrows indicate light rays.

[0043] The refractive index of the light emitting section 110 is determined by the material of the light emitting layer of the light emitting element 112. The material of the light emitting layer is determined by the required light emitting characteristics. The refractive index n0 of the light emitting section 110 is, for example, 1.5 or more and 1.7 or less.

[0044] Moreover, the protective layer 120 is determined by the reliability required for the surface-emitting device 100. To ensure the reliability, the protective layer 120 is preferably configured with the above-mentioned dense structure. For this reason, the refractive index n1 of the protective layer 120 is, for example, higher than the refractive index n0 of the light-emitting section 110 (n1>n0). The refractive index n1 of the protective layer 120 is, for example, greater than 1.7 and equal to or less than 2.0, and is preferably 1.9.

[0045] As shown in FIG. 2A, in a surface-emitting device 10 having only the light-emitting section 110 and the protective layer 120, the surface 122 of the protective layer 120 is exposed to air (outside). The refractive index nA of air is about 1.0. Therefore, since the difference between the refractive index nA of air and the refractive index n1 of the protective layer 120 is large, most of the light emitted from the light-emitting section 110 and passing through the protective layer 120 is reflected at the boundary surface between the protective layer 120 and the air (surface 122 of the protective layer 120). As a result, the light emitted from the light-emitting section 110 is confined inside the protective layer 120, and the light extraction efficiency in the front direction is low. The front direction is the direction of the normal to the light-emitting surface 110a. The light extraction efficiency is the efficiency at which the light emitted by the light-emitting section 110 is released to the outside.

[0046] 2B, a surface-emitting device 20 may be considered in which a first layer 22 having a lower refractive index than the protective layer 120 is laminated on a surface 122 of the protective layer 120. The first layer 22 is a layer having a uniform thickness.

[0047] When the refractive index n2 of the first layer 22 is equal to or greater than the refractive index nA of air and less than the refractive index n1 of the protective layer 120, most of the light emitted from the light emitting section 110 and passing through the protective layer 120 can exit from the surface 122 of the protective layer 120 and pass through the first layer 22. However, depending on the refractive index n3 of the second layer 24 laminated on the first layer 22, light may be trapped inside the first layer 22 and inside the second layer 24.

[0048] Therefore, as shown in FIG. 2C, a surface-emitting device 100 is provided in which a lens layer 130 is laminated on the surface 122 of the protective layer 120. As described above, the lens layer 130 is composed of the first lens layer 140 and the second lens layer 150. The refractive index of the lens layer 130 (the refractive index n3 of the first lens layer 140 and the refractive index n2 of the second lens layer 150) is preferably equal to or lower than the refractive index n1 of the protective layer 120, and more preferably lower than the refractive index n1 of the protective layer 120. This allows most of the light emitted from the light-emitting section 110 and passing through the protective layer 120 to be extracted to the outside through the lens layer 130. The refractive index of the lens layer 130 is, for example, 1.4 or more and 1.8 or less, and preferably 1.5 or more and 1.7 or less.

[0049] 3A, in the case where the multiple microlenses 160 formed in the first lens layer 140 are concave lenses recessed toward the base layer 170, if the refractive index n3 of the first lens layer 140 is higher than the refractive index n2 of the second lens layer 150 (n3>n2), the light emitted from the second lens layer 150 is refracted in the lateral direction of the first lens layer 140 (the XY direction in FIG. 3B). This reduces the amount of light emitted from the surface 142b of the first lens layer 140. The surface 142b is the surface of the first lens layer 140 opposite to the surface 142a on which the multiple microlenses 160 are formed.

[0050] Therefore, as shown in FIG. 3B, when the plurality of microlenses 160 formed on the first lens layer 140 are concave lenses recessed toward the substrate layer 170 side, the refractive index n3 of the first lens layer 140 is preferably lower than the refractive index n2 of the second lens layer 150 (n3 < n2). Thereby, the first lens layer 140 can condense the light emitted from the second lens layer 150 toward the surface 142b side of the first lens layer 140. The refractive index n3 of the first lens layer 140 is, for example, 1.4 or more and 1.6 or less, and preferably 1.5. The refractive index n2 of the second lens layer 150 is, for example, 1.6 or more and 1.8 or less, and preferably 1.7.

[0051] The refractive index of the substrate layer 170 is preferably lower than the refractive index n1 of the protective layer 120. Thereby, the light condensed toward the surface 142b side of the first lens layer 140 can be efficiently emitted in the front direction from the surface side of the substrate layer 170, and the light extraction efficiency in the front direction can be improved. Also, the refractive index of the substrate layer 170 may be lower or higher than the refractive index of the lens layer 130, but is preferably lower than the refractive index of the lens layer 130. Thereby, the light extraction efficiency in the front direction can be further improved. The refractive index of the substrate layer 170 is, for example, 1.3 or more and 1.9 or less, and preferably 1.6.

[0052] Also, as shown in FIG. 4, the plurality of microlenses 160 formed on the first lens layer 140 may be convex lenses protruding toward the protective layer 120 side. In this case, the refractive index n3 of the first lens layer 140 is preferably higher than the refractive index n2 of the second lens layer 150 (n3 > n2). Thereby, as shown in FIG. 4B, the first lens layer 140 can condense the light emitted from the second lens layer 150 toward the surface 142b side of the first lens layer 140.

[0053] <3. Outline of the First Lens Layer and Microlenses> The first lens layer 140 is composed of a plurality of microlenses 160 randomly arranged and deployed on the XY plane. The microlenses 160 are made of a convex structure (convex lens) or a concave structure (concave lens) having a light diffusing function, and have, for example, an aperture width D (lens diameter) of about several tens of μm and a curvature radius R of about several tens of μm.

[0054] In this embodiment, the curved shape (lens surface shape) of the lens surface of each microlens 160 has an aspheric shape, such as an ellipsoid, paraboloid, or hyperboloid, and each microlens 160 is an aspheric lens.

[0055] Moreover, according to this embodiment, the microlenses 160 are arranged at irregular positions on the XY plane parallel to the light-emitting surface 110a. For example, the microlenses 160 may be arranged at irregular positions while overlapping each other on the XY plane so that the overlap amount Ov between the adjacent microlenses 160 is within a predetermined allowable range. Furthermore, the aperture width D and the curvature radius R of each microlens 160 may vary irregularly so that the aperture width D (lens diameter) and the curvature radius R of the microlenses 160 are different from each other. In this case, the aperture width D of each microlens 160 may vary irregularly within a range of a predetermined variation rate δD based on a predetermined reference aperture width Dk (D[μm]=Dk[μm]±δD[%]). Similarly, the radius of curvature R of each microlens 160 may vary irregularly within a range of a predetermined variation rate δR based on a predetermined reference radius of curvature Rk (R [μm] = Rk [μm] ± δR [%]).

[0056] In this manner, in this embodiment, the arrangement of the multiple microlenses 160, the opening width D, the curvature radius R, and the like may be varied irregularly. As a result, the surface shapes of the multiple microlenses 160 arranged and developed on the XY plane vary irregularly and become different shapes from one another.

[0057] This allows for the realization of a highly irregular three-dimensional surface structure of the first lens layer 140 (microlens array), making it possible to control the overlapping state of the phases of the diffused light emitted from each microlens 160. This makes it possible to reduce unevenness in the intensity distribution of the diffused light due to interference and diffraction of the diffused light emitted from the multiple microlenses 160, and to distribute the diffused light uniformly. As a result, it is possible to control the cutoff property of the intensity distribution of the diffused light while having high transmittance luminance characteristics and satisfying the uniformity of the light distribution of the diffused light.

[0058] The first lens layer 140 according to this embodiment having the above-mentioned characteristics will be described in detail below.

[0059] <4. Overall configuration of the first lens layer> Next, a layout pattern of microlenses 160 in first lens layer 140 according to one embodiment of the present invention will be described with reference to Fig. 5. Fig. 5 is a plan view and an enlarged view showing a schematic view of first lens layer 140 according to this embodiment.

[0060] 5, the first lens layer 140 according to this embodiment is composed of a plurality of unit cells 144. The unit cells 144 are a basic arrangement pattern of microlenses 160. On the surface of each unit cell 144, a plurality of microlenses 160 are arranged in a predetermined layout pattern (arrangement pattern).

[0061] 5 shows an example in which the shape of unit cells 144 constituting first lens layer 140 is rectangular, particularly square. However, the shape of unit cells 144 is not limited to the example shown in Fig. 5, and may be any shape, such as an equilateral triangle or a regular hexagon, as long as it can fill light-emitting surface 110a (XY plane) of light-emitting section 110 without gaps.

[0062] When the surface of the first lens layer 140 is divided into a plurality of unit regions, the unit cells 144 correspond to the individual unit regions. In the example of FIG. 5, a plurality of square unit cells 144 are repeatedly arranged vertically and horizontally on the XY plane. The number of unit cells 144 constituting the first lens layer 140 is not particularly limited, and the first lens layer 140 may be composed of one unit cell 144, or may be composed of a plurality of unit cells 144. In the first lens layer 140, unit cells 144 having different surface structures may be repeatedly arranged, or unit cells 144 having the same surface structure may be repeatedly arranged.

[0063] As shown in the enlarged view on the right side of FIG. 5, the layout pattern (arrangement pattern) of the microlenses 160 provided in the unit cell 144 is continuous between the adjacent unit cells 144 in the arrangement direction of the unit cells 144 (in other words, the array arrangement direction). The first lens layer 140 (microlens array) is formed by arranging the unit cells 144 without gaps while maintaining the continuity of the microlenses 160 at the boundary between the adjacent unit cells 144. Here, the continuity of the microlenses 160 means that the microlenses 160 located on the outer edge of one unit cell 144 and the microlenses 160 located on the outer edge of the other unit cell 144 of two adjacent unit cells 144, 144 are continuously connected without any misalignment in planar shape or step in height.

[0064] Thus, in the first lens layer 140 according to this embodiment, the unit cells 144 (basic structure) of the microlens array are arranged without gaps while maintaining the continuity of the boundaries, thereby forming a microlens array. This makes it possible to prevent unintended problems such as diffraction, reflection, and scattering of light at the boundaries between adjacent unit cells 144, 144, and obtain desired light distribution characteristics by the first lens layer 140. Furthermore, by forming the microlens array into a structure in which the unit cells 144 are repeated, it is possible to improve the design efficiency and productivity of the microlens array.

[0065] 5. Configuration of First Lens Layer 140 Next, the configuration of first lens layer 140 according to this embodiment will be described in more detail with reference to Figs. 6 to 8. Fig. 6 is an enlarged plan view and an enlarged cross-sectional view that typically show the configuration of first lens layer 140 according to this embodiment. Fig. 7 is an enlarged cross-sectional view that typically shows the vicinity of the boundary of microlens 160 according to this embodiment. Fig. 8 is a plan view that typically shows the planar shape (outer shape) of microlens 160 when microlens 160 is viewed in plan from a direction perpendicular to surface 142b of first lens layer 140 according to this embodiment.

[0066] First lens layer 140 is provided on the surface of base layer 170 facing light emitting section 110. As shown in FIG. 6, first lens layer 140 is a collection of a plurality of microlenses 160 (single lenses) arranged on the surface of base layer 170.

[0067] The surface of the base material layer 170 on which the first lens layer 140 is provided may be, for example, a flat surface. The flat surface of the base material layer 170 is preferably parallel to the light emitting surface 110a of the light emitting section 110. Hereinafter, the flat surface of the base material layer 170 may be referred to as an XY plane. The X and Y directions in the XY plane are parallel to the surface of the base material layer 170. The X and Y directions are perpendicular to each other. The Z direction is perpendicular to the surface of the base material layer 170 (i.e., the normal direction), and corresponds to the thickness direction of the surface emitting device 100. The Z direction is perpendicular to the XY plane, the X direction, and the Y direction.

[0068] Microlens 160 is a minute optical lens on the order of several tens of μm, for example. Microlens 160 constitutes a single lens of first lens layer 140. Microlens 160 may have a concave structure (concave lens) formed so as to be recessed toward base layer 170, or may have a convex structure (convex lens) formed so as to protrude from base layer 170 to protective layer 120. In the example shown in FIGS. 6 to 8, a case will be described in which microlens 160 has a convex structure (convex lens).

[0069] The surface shape of the microlens 160 has an aspheric shape. The surface shape of the microlens 160 is not particularly limited as long as it is a curved shape that includes at least a part of an aspheric component. For example, the surface shape of the microlens 160 may be an aspheric shape that includes only an aspheric component, or may be a curved shape that includes an aspheric component and a spherical component or other curved component. For example, the surface shape of the apex side of the lens surface of the microlens 160 may be aspheric, and the surface shape of the other part may be spherical. Such a surface shape is also included in the aspheric shape of the microlens 160 according to this embodiment.

[0070] As shown in FIG. 6, it is preferable that the multiple microlenses 160 are arranged densely so that they are adjacent to each other without any gaps. In other words, it is preferable that the multiple microlenses 160 are arranged continuously so that there is no gap (flat part) at the boundary part between the adjacent microlenses 160, 160. It is preferable that the microlenses 160 are arranged on the base layer 170 without any gaps. In other words, it is preferable that the microlenses 160 are arranged so that the packing ratio of the microlenses 160 is 100%. This makes it possible to suppress a component (hereinafter also referred to as a "zero-order transmitted light component") that is transmitted as it is without being scattered at the boundary surface between the second lens layer 150 and the first lens layer 140, among the incident light that is incident from the second lens layer 150. As a result, it is possible to further improve the diffusion performance by the first lens layer 140 in which the multiple microlenses 160 are arranged adjacent to each other without any gaps.

[0071] In order to suppress the zero-order transmitted light component, the filling rate of the microlenses 160 on the base layer 170 is preferably 90% or more, and more preferably 100%. Here, the filling rate refers to the ratio of the area of ​​the portion on the surface (XY plane) of the base layer 170 that is occupied by the multiple microlenses 160. If the filling rate is 100%, the surface of the microlens array is formed of curved surface components and contains almost no flat surface components.

[0072] However, in the actual manufacture of the first lens layer 140, in order to continuously connect the curved surfaces of the multiple microlenses 160, the vicinity of the inflection point at the boundary between the adjacent microlenses 160, 160 may become substantially flat. In such a case, the width of the substantially flat region near the inflection point at the boundary between the microlenses 160, 160 (the width of the boundary line 162 between the microlenses 160, 160 shown in FIG. 7 and FIG. 8) is preferably 1 μm or less. This allows the zero-order transmitted light component to be sufficiently suppressed.

[0073] Furthermore, in the first lens layer 140 according to this embodiment, the microlenses 160 are irregularly (randomly) arranged on the XY plane. Here, "irregular" means that there is no substantial regularity in the arrangement of the microlenses 160 in any region of the first lens layer 140. However, even if there is some regularity in the arrangement of the microlenses 160 in a small region, the arrangement of the microlenses in any region as a whole is considered to be included in "irregular". Note that a method for irregularly arranging the microlenses 160 in the first lens layer 140 according to this embodiment will be described later.

[0074] Furthermore, lens parameters such as the aperture width D and the radius of curvature R that determine the surface shape of each microlens 160 may vary irregularly for each microlens 160. In other words, the aperture width D and the radius of curvature R of each microlens 160 may be irregularly varying values ​​rather than predetermined fixed values. The aperture width D is the width of the opening of the microlens 160 in the X or Y direction, and corresponds to the lens diameter of the microlens 160. The radius of curvature R is the radius of curvature of the curved shape of the microlens 160 in the X or Y direction.

[0075] For example, the aperture width D of each microlens 160 may vary irregularly within a range of a predetermined variation rate δD with respect to a predetermined reference aperture width Dk (D=Dk±δD%). Similarly, the curvature radius R of each microlens 160 may vary irregularly within a range of a predetermined variation rate δR with respect to a predetermined reference radius of curvature Rk (R=Rk±δR%). This allows the aperture width D and the curvature radius R to vary appropriately with respect to the predetermined reference aperture width Dk and the reference radius of curvature Rk as the center, thereby reducing unevenness in the intensity distribution of diffused light (uneven brightness, uneven color, etc.) caused by interference and diffraction of light from each microlens 160 while maintaining the desired optical characteristics (diffusion performance) of the surface-emitting device 100.

[0076] Thus, in the microlens array according to this embodiment, the radius of curvature R and the aperture width D of each microlens 160 vary irregularly within a predetermined range centered on the reference radius of curvature Rk and the reference aperture width Dk, and have variations. The phase distribution of the optical aperture of each microlens 160 differs depending on the orientation. Furthermore, on the surface (XY plane) of the base layer 170, a plurality of microlenses 160 are densely and continuously arranged so as to overlap each other, and each microlens 160 is arranged at an irregular position on the XY plane.

[0077] As a result, the surface shape (three-dimensional curved shape) and planar shape (shape projected onto the XY plane of the base layer 170) of each microlens 160 vary irregularly with respect to a predetermined reference shape. As a result, the surface shapes and planar shapes of each microlens 160 are different from one another. Therefore, the multiple microlenses 160 have various planar shapes, as shown typically in FIG. 6, and many of them are not symmetrical.

[0078] As a result, as shown in FIG. 7, the radius of curvature of the microlens 160A becomes R A Meanwhile, the radius of curvature of the microlens 160B adjacent to the microlens 160A is R B (≠R AThe radius of curvature R of the adjacent microlenses 160A and 160B is A , R B are different from each other, the boundary line 162 between the microlenses 160A and 160B is not formed only by straight lines, but is formed to include at least a part of a curve.

[0079] Specifically, as shown in Fig. 8, consider a case where the microlens 160 is viewed in plan from a normal direction (Z direction) perpendicular to the surface of the base layer 170. In this case, the outline of the planar shape of the microlens 160 (boundary line 162 between the microlens 160 and other adjacent microlenses 160) is composed of multiple curved lines with different curvatures. In this way, when the boundary line 162 between adjacent microlenses 160, 160 includes multiple curved lines with different curvatures, the regularity of the boundary between the microlenses 160, 160 is further broken, and the diffraction component of the diffused light can be further reduced.

[0080] <6. Arrangement of Microlenses for Light Emitting Element> Next, a description will be given of the arrangement of the microlenses 160 with respect to the light-emitting elements 112. Fig. 9 is a projection diagram showing the planar shapes of the light-emitting elements 112 and the microlenses 160 when the light-emitting elements 112 and the microlenses 160 according to this embodiment are projected onto the XY plane.

[0081] 9, in this embodiment, when the multiple light-emitting elements 112 and the multiple microlenses 160 are projected onto the XY plane (projection surface 114), the multiple microlenses 160 are irregularly arranged on the XY plane such that at least a portion of at least four or more microlenses overlaps with one light-emitting element 112. Also, on the projection surface 114, the four or more microlenses 160 are arranged so that at least a portion of each of the multiple light-emitting elements 112 overlaps with each other.

[0082] Furthermore, even if the relative position of the lens layer 130 in the X-direction or Y-direction with respect to the light-emitting element 112 on the XY plane is shifted from the design value within a predetermined distance, the multiple microlenses 160 are irregularly arranged on the XY plane so that at least a part of at least four or more microlenses 160 overlaps one light-emitting element 112. Therefore, each light emitted from one light-emitting element 112 is diffused by at least four or more microlenses 160. The predetermined distance is, for example, within the range of the maximum length in the planar shape of one light-emitting element 112 (for example, within the range of 20 μm). For example, when the planar shape of the light-emitting element 112 is rectangular, the maximum length in the planar shape of the light-emitting element 112 may be the length of the long side of the rectangle or the longest length of the diagonal line. For example, when the planar shape of the light-emitting element 112 is triangular or hexagonal, the maximum length in the planar shape of the light-emitting element 112 may be the longest length of the diagonal line. Furthermore, for example, when the planar shape of the light emitting element 112 is a perfect circle, the maximum length in the planar shape of the light emitting element 112 may be the length of the diameter. When the planar shape of the light emitting element 112 is an ellipse, the maximum length in the planar shape of the light emitting element 112 may be the length of the major axis.

[0083] As described above, the surface shapes of the microlenses 160 vary irregularly and are different from one another. Therefore, for each light emitting element 112, it is possible to reduce unevenness in the intensity distribution of the diffused light due to interference and diffraction of the diffused light emitted from four or more microlenses 160, and to distribute the diffused light uniformly.

[0084] Furthermore, the surface shapes of the microlenses 160 are different from one another. Therefore, even if the relative position of the lens layer 130 with respect to the light emitting element 112 is shifted, the four or more microlenses 160 having different shapes from one another can diffuse the light emitted from the light emitting element 112. Therefore, it is possible to suppress a decrease in the light extraction efficiency without aligning (positioning) the microlenses 160 and the light emitting element 112 with high accuracy.

[0085] Furthermore, as described above, since the lens layer 130 is made of resin, the lens layer 130 (microlenses 160) may shrink in the XY directions in the process of laminating the lens layer 130 on the light-emitting section 110. In such a case, the relative position of the microlenses 160 with respect to the light-emitting element 112 may deviate from the design value due to the shrinkage of the microlenses 160. Even in such a case, the surface-emitting device 100 according to this embodiment can diffuse the light emitted from the light-emitting element 112 by four or more microlenses 160 having mutually different shapes.

[0086] In order to achieve such an arrangement, it is preferable that the aperture size Sm of the microlens 160 is 55% or less of the size Sl of the planar shape of the light-emitting element 112. The aperture size Sm of the microlens 160 is, for example, the diameter of an inscribed circle 166 of the microlens 160 as shown in FIG. 9. The inscribed circle 166 is a perfect circle inscribed in the aperture shape (irregular planar shape) of the microlens 160. The size Sl of the light-emitting element 112 is, for example, the length of the shortest side among multiple sides constituting the planar shape of the light-emitting element 112. For example, as shown in FIG. 9, when the planar shape of the light-emitting element 112 is rectangular, the size Sl of the light-emitting element 112 may be the length of the short side of the rectangle.

[0087] As described above, the outline of the planar shape of microlens 160 is composed of multiple curves with different curvatures (see FIG. 8). Therefore, strictly speaking, inscribed circle 166 of microlens 160 rarely touches all of the outline of the planar shape of microlens 160. For this reason, in this embodiment, the perfect circle contained within the outline (outer edge) of microlens 160 and having the largest area is called inscribed circle 166 of microlens 160.

[0088] Furthermore, it is preferable that the lower limit of the aperture size Sm of the microlens 160 is larger than the wavelength of the light emitted by the light emitting element 112. If the aperture size Sm of the microlens 160 becomes approximately the same as the wavelength of the light emitted by the light emitting element 112, the microlens 160 will no longer function as a lens due to a wave optics diffraction phenomenon. It is preferable that the lower limit of the aperture size Sm of the microlens 160 is larger than the wavelength (700 nm) of "R (red)" light, for example.

[0089] Furthermore, in consideration of the manufacturing process of the first lens layer 140 (microlens array), the lower limit of the aperture size Sm of the microlens 160 is preferably 7.5 μm. This makes it possible to prevent the lens shape from becoming “rounded” and to prevent deviation from the designed shape.

[0090] Moreover, it is preferable that the aperture size Sm of 50% or more of the microlenses 160 among the many microlenses 160 formed in the first lens layer 140 is 55% or less of the size Sl of the light-emitting element 112. It is more preferable that the aperture size Sm of all the microlenses 160 is 55% or less of the size Sl of the light-emitting element 112. However, this is not limited to such an example, and for example, the aperture size Sm of some of the microlenses 160 among the multiple microlenses 160 formed in the first lens layer 140 may be 55% or less of the size Sl of the light-emitting element 112.

[0091] 9, at least two or more microlenses 160 may be arranged so that their centers P overlap with one light-emitting element 112 on the projection surface 114. This makes it possible to suppress a decrease in light extraction efficiency without highly accurate alignment between the microlenses 160 and the light-emitting element 112. The center P of the microlens 160 is, for example, the center of an inscribed circle 166, the center of gravity of the planar shape of the microlens 160, or the lens center coordinates pn described later.

[0092] Furthermore, the opening area of ​​the microlens 160 may be 30% or less of the planar area of ​​the light emitting element 112. This makes it possible to suppress a decrease in light extraction efficiency without aligning the microlens 160 and the light emitting element 112 with high accuracy.

[0093] Furthermore, the aperture size Sm of the microlens 160 may be, for example, the diameter of the circumscribing circle of the microlens 160.

[0094] Furthermore, when the planar shape of the light emitting element 112 is a square, the size Sl of the light emitting element 112 may be the length of one side of the square. Furthermore, when the planar shape of the light emitting element 112 is a polygon, the size Sl of the light emitting element 112 may be, for example, the shortest diagonal of the diagonal of the polygon. Furthermore, when the planar shape of the light emitting element 112 is a circle, the size Sl of the light emitting element 112 may be, for example, the diameter of the circle. When the planar shape of the light emitting element 112 is an ellipse, the size Sl of the light emitting element 112 may be, for example, the minor axis of the ellipse.

[0095] <7. Microlens design method> Next, a method for designing a microlens according to this embodiment will be described with reference to Fig. 10 to Fig. 14. Fig. 10 is a flowchart showing the method for designing a microlens according to this embodiment.

[0096] (S10) Setting the lens center coordinates 10, first, the lens center coordinate pn of each microlens 160 is set on the surface 142a (on the XY plane) of the first lens layer 140. The lens center coordinate pn is the coordinate on the XY plane of the center point of each microlens 160. When setting the lens center coordinate pn, it is preferable that the multiple lens center coordinates pn are set at irregular positions so that the intervals between the multiple lens center coordinates pn on the XY plane are distributed within a preset range.

[0097] 11, a plurality of lens center coordinates pn (xpn, ypn) are set on the XY plane of a unit cell 144 of the first lens layer 140 whose size is set in advance. Note that n is the number of installed microlenses 160 (n=1, 2, 3, . . .). The plurality of lens center coordinates pn (xpn, ypn) are arranged on the XY plane such that the intervals between the plurality of lens center coordinates pn are within a preset range.

[0098] 12, an adjustment process may be performed on the overlap amount Ov between adjacent microlenses 160, 160, if necessary. By this adjustment process, the lens center coordinates pn are adjusted so that the overlap amount Ov between adjacent microlenses 160, 160 on the XY plane falls within a preset allowable range (for example, equal to or less than a preset value), and the lens center coordinates pn of the multiple microlenses 160 are irregularly arranged.

[0099] 12, first, the x and y coordinates of the lens center coordinates pn and the lens radius r of the newly placed microlens 160 are determined by random numbers. Next, the overlap amount Ov between the planar shape of each microlens 160 already placed and the planar shape of the newly placed microlens 160 is calculated. The overlap amount Ov is the overlap width between the planar shapes of two adjacent microlenses 160, 160, and can be calculated by the following formula (1).

[0100] Ov = ri + rj - ((xi - xj) 2 +(yi-yj) 2 ) 0.5 (1) In the formula (1), the parameters are as follows: Ov: Amount of overlap between adjacent microlenses 160, 160 xi, yi: lens center coordinates pi of one microlens 160 ri: radius of one microlens 160 xj, yj: lens center coordinates pj of the other microlens 160 rj: radius of the other microlens 160

[0101] In this way, when a new microlens 160 is arranged on the XY plane, the overlap amount Ov with the already arranged microlens 160 is calculated, and if the overlap amount Ov is within a preset allowable range, the new microlens 160 is arranged. Conversely, if the calculated overlap amount Ov is outside the allowable range (for example, if it exceeds the upper limit of the allowable range or is less than the lower limit of the allowable range), the new microlens 160 is not arranged. It is preferable to determine the allowable range in advance according to the optical characteristics required for the first lens layer 140 (microlens array), etc.

[0102] In this manner, as shown in FIG. 12, the lens center coordinates pn of the microlenses 160 may be irregularly arranged on the XY plane, while the overlap amount Ov may be adjusted within the allowable range. This allows the microlenses 160 to be arranged at irregular positions on the XY plane, while overlapping each other with an appropriate overlap amount Ov. Therefore, the occurrence of flat parts that do not become lens surfaces between the adjacent microlenses 160, 160 can be suppressed, and the occurrence of zero-order diffracted light that passes through the flat parts of the boundary surface between the second lens layer 150 and the first lens layer 140 can be suppressed. In addition, the unevenness of the intensity distribution of the diffused light due to interference and diffraction of the diffused light emitted from the multiple microlenses 160 can be reduced. Furthermore, since the microlenses 160, 160 do not overlap each other excessively, the moldability and feasibility of the microlens array structure are not impaired.

[0103] (S12) Lens parameter setting Next, lens parameters of each microlens 160 are set as shown in Fig. 10. The lens parameters are parameters that determine the surface shape (lens surface shape) of the microlens 160. The lens parameters are preferably set irregularly within a preset variation range.

[0104] When the lens surface shape is a reference aspheric shape that is rotationally symmetric about the optical axis, such as an ellipsoid (the surface of a spheroid whose axis of rotation is the direction of the optical axis), a paraboloid, a hyperboloid, etc. (see FIG. 12), the lens parameters include, for example, the aperture width D (lens diameter) of the microlens 160 and the radius of curvature R of the apex of the microlens 160.

[0105] The aperture width D and the radius of curvature R of each microlens 160 may be set to values ​​that vary irregularly so that the aperture width D and the radius of curvature R of the multiple microlenses 160 are different from each other. In this case, the aperture width D may be set to a value that varies irregularly within a range of a predetermined variation rate δD with a predetermined reference aperture width Dk as a reference (D=Dk±δD%). Similarly, the radius of curvature R of each microlens 160 may be set to a value that varies irregularly within a range of a predetermined variation rate δR with a predetermined reference radius of curvature Rk as a reference (R=Rk±δR%). In this way, by varying the aperture width D and the radius of curvature R, which are lens parameters, the lens surface shapes (rotationally symmetric reference aspheric shapes) of the multiple microlenses 160 can be varied to set them to different aspheric shapes.

[0106] On the other hand, as shown in FIG. 13, when the lens surface shape is an aspheric shape that is rotationally asymmetric around the optical axis 164 and has anisotropy, such as an anamorphic shape or a torus shape, the lens parameters may be parameters used in a function (z=f(d)) that defines the aspheric shape. In this case, the value z in the height direction of the lens surface shape is expressed as a function (z=f(d)) of a distance d from the lens center coordinate pn on the XY plane. The distance d may include a distance dx in the X direction from the lens center coordinate pn on the XY plane and a distance dy in the Y direction. The position z in the height direction of the lens surface shape can be determined by a function using the distances dx and dy (z=f(dx, dy)). By irregularly varying the parameters included in the function (z=f(d)) that represents such a lens surface shape, the lens surface shapes (rotationally asymmetric aspheric shapes) of the multiple microlenses 160 can be varied to set them to different aspheric shapes.

[0107] When the lens surface shape is a reference aspheric shape (e.g., an ellipsoid, a paraboloid, a hyperboloid, etc.) that is rotationally symmetric about the optical axis 164, the planar shape of the microlens 160 is, for example, a circle as shown in Fig. 12. On the other hand, when the lens surface shape is a reference aspheric shape (e.g., an anamorphic shape, a torus shape) that is rotationally asymmetric about the optical axis 164, the planar shape of the microlens 160 is, for example, an ellipse or a shape that approximates an ellipse as shown in Fig. 13.

[0108] Whether the lens surface shape is a reference aspheric shape that is rotationally symmetric about the optical axis 164 or a reference aspheric shape that is rotationally asymmetric about the optical axis 164, the aperture width D is set so that at least a portion of at least four or more microlenses 160 overlaps with one light-emitting element 112 on the projection surface 114.

[0109] (S14) Determining the lens surface shape Next, the lens surface shape of each microlens 160 is determined based on the lens parameters set in S12. Specifically, as shown in Fig. 14, the Z coordinate position representing the surface shape of each microlens 160 is calculated based on the lens parameters set above, and the lens surface shape of the microlens 160 is set. Then, the height position in the Z direction of the set lens surface shape is adjusted so that the size (e.g., aperture width D) on the XY plane of the set lens surface shape matches the size of the parameter set in S12 above (e.g., aperture width D set in S12 above). Then, the horizontal cross section of the lens surface shape in the XY plane after the height position adjustment is set as a cross section at the position z = 0.

[0110] As described above, according to the design method of the microlens 160 of this embodiment, the parameters (e.g., the aperture width D, the radius of curvature R, etc.) that define the lens surface shape are irregularly varied. Furthermore, it is preferable that the multiple microlenses 160 are arranged so as to overlap each other without gaps, and that there is no flat portion at the boundary between the adjacent microlenses 160. This makes it possible to provide each microlens 160 with different diffusion characteristics while continuously arranging multiple microlens arrays on the XY plane without gaps. The microlens array having such a configuration has small macro light amount fluctuations that depend on the lens surface structure and small light amount changes due to diffracted light, and has a variety of light distribution controllability with high uniformity.

[0111] Furthermore, according to the method for designing the microlenses 160 according to this embodiment, the aperture width D is varied irregularly and set so that at least four or more microlenses 160 at least partially overlap one light-emitting element 112 on the projection surface 114. This makes it possible to eliminate the need for highly accurate positioning of the light-emitting section 110 and the first lens layer 140 when manufacturing the surface-emitting device 100.

[0112] <8. Manufacturing method of surface-emitting device> Next, a method for manufacturing the surface-emitting device 100 according to this embodiment will be described with reference to Fig. 15. Fig. 15 is a flowchart showing the method for manufacturing the surface-emitting device 100 according to this embodiment. Fig. 16 is a process diagram showing S117 according to this embodiment. Fig. 17 is another process diagram showing S117 according to this embodiment. Fig. 18 is a cross-sectional view diagrammatically showing another example of the surface-emitting device 100 according to this embodiment.

[0113] 15, in the method for manufacturing the surface-emitting device 100 according to this embodiment, first, a substrate (a substrate of a master or a substrate layer 170 of the surface-emitting device 100) is cleaned (step S101). The substrate may be, for example, a roll-shaped substrate such as a glass roll, or a flat substrate such as a glass wafer or a silicon wafer.

[0114] Next, a resist is formed on the surface of the substrate after cleaning (step S103). For example, a resist layer can be formed by using a resist made of a metal oxide. Specifically, a resist layer can be formed on a roll-shaped substrate by spraying or dipping the resist. On the other hand, a resist layer can be formed on a flat substrate by subjecting the resist to various coating processes. As the resist, a positive photoreactive resist or a negative photoreactive resist can be used. A coupling agent can be used to increase the adhesion between the substrate and the resist.

[0115] Furthermore, the resist layer is exposed using a pattern corresponding to the shape of the first lens layer 140 (microlens array) (step S105). For this exposure process, a known exposure method such as exposure using a grayscale mask, multiple exposure by overlapping multiple grayscale masks, or laser exposure using a picosecond pulse laser or a femtosecond pulse laser may be appropriately applied.

[0116] Thereafter, the exposed resist layer is developed (S107). A pattern is formed in the resist layer by this development process. The development process can be carried out by using an appropriate developer depending on the material of the resist layer. For example, when the resist layer is formed of a resist using a metal oxide, the resist layer can be alkaline developed by using an inorganic or organic alkaline solution.

[0117] Next, the developed resist layer is used for sputtering or etching (S109), completing a master disk having the shape of a microlens array formed on its surface (S111). Specifically, a glass master can be manufactured by glass etching a glass substrate using the patterned resist layer as a mask. Alternatively, a metal master can be manufactured by Ni sputtering or nickel plating (NED treatment) on the patterned resist layer to form a nickel layer to which the pattern is transferred, and then peeling off the substrate. For example, a metal master can be manufactured by forming a nickel layer to which the resist pattern is transferred by Ni sputtering with a film thickness of about 50 nm, or nickel plating (for example, Ni sulfamate bath) with a film thickness of 100 μm to 200 μm, or the like.

[0118] Furthermore, the master master (e.g., a glass master master, a metal master master) completed in S111 above is used to transfer (imprint) a pattern onto a resin film or the like, thereby creating a soft mold with an inverted shape of the microlens array formed on its surface (S113).

[0119] Thereafter, the pattern of the microlens array is transferred to a substrate layer 170 such as a glass substrate or a film substrate using a soft mold, to manufacture a diffuser plate 50 in which a first lens layer 140 is laminated on the substrate layer 170 as shown in Fig. 16 (S115). Note that, although the multiple microlenses 160 formed in the first lens layer 140 are convex lenses in the example shown in Fig. 16, the multiple microlenses 160 formed in the first lens layer 140 may be concave lenses (see Fig. 1).

[0120] Then, in S117, as shown in FIG. 16, an uncured resin composition 60 is supplied to a surface of the light-emitting plate 52 on the side of the protective layer 120, in which the protective layer 120 is laminated on the light-emitting section 110. The uncured resin composition 60 is an uncured product of the resin constituting the second lens layer 150. When the plurality of microlenses 160 formed in the first lens layer 140 are convex lenses, the uncured resin composition 60 is selected so that the refractive index of the first lens layer 140 is higher than that of the second lens layer 150. When the plurality of microlenses 160 formed in the first lens layer 140 are concave lenses, the uncured resin composition 60 is selected so that the refractive index of the first lens layer 140 is lower than that of the second lens layer 150.

[0121] Next, the surface 142a of the first lens layer 140 of the diffusion plate 50 is opposed to the uncured resin composition 60 formed on the light-emitting plate 52, and the diffusion plate 50 and the light-emitting plate 52 are brought close to each other, so that the uncured resin composition 60 is spread between the first lens layer 140 of the diffusion plate 50 and the protective layer 120 of the light-emitting plate 52. As a result, a layer 62 of the uncured resin composition 60 (hereinafter referred to as the "uncured resin layer 62") is formed between the first lens layer 140 of the diffusion plate 50 and the protective layer 120 of the light-emitting plate 52, and the diffusion plate 50 and the light-emitting plate 52 are bonded together by the uncured resin layer 62. Then, the uncured resin layer 62 is cured, so that the cured uncured resin layer 62 forms the second lens layer 150, and the surface-emitting device 100 according to this embodiment is manufactured.

[0122] In the above, an example has been described in which a soft mold is manufactured (S113) using a master (S111), and then the diffusion plate 50 is manufactured (S115) by transfer using the soft mold. However, the present invention is not limited to this example, and a master (e.g., an inorganic glass master) on which an inverted shape of a microlens array is formed may be manufactured, and the diffusion plate 50 may be manufactured by imprinting using the master. For example, the diffusion plate 50 can be manufactured by applying an acrylic photocurable resin to a base material made of PET (PolyEthylene Terephthalate) or PC (PolyCarbonate), transferring the pattern of the master to the applied acrylic photocurable resin, and curing the acrylic photocurable resin with UV light.

[0123] On the other hand, when manufacturing the diffusion plate 50 by directly processing the glass substrate (substrate layer 170) itself, following the development process in step S107, a dry etching process is performed on the substrate layer 170 using a known compound such as CF4 (S119), and then an uncured resin layer is formed and cured (S121), thereby manufacturing the surface-emitting device of this embodiment.

[0124] It should be noted that the manufacturing method shown in FIG. 15 is merely one example, and the manufacturing method of the surface emitting device is not limited to the above example.

[0125] 17, in S115, a soft mold or a master disk may be used to transfer a pattern of a microlens array to the protective layer 120 of the light-emitting plate 52, thereby manufacturing a laminate 70 in which a first lens layer 140 is laminated on the protective layer 120 of the light-emitting plate 52. Note that in the example shown in Fig. 17, the multiple microlenses 160 formed in the first lens layer 140 are convex lenses, but as shown in Fig. 18, the multiple microlenses 160 formed in the first lens layer 140 may be concave lenses.

[0126] In this case, in S117, uncured resin composition 60 is supplied to the surface of base material layer 170. When the plurality of microlenses 160 formed in first lens layer 140 are convex lenses, uncured resin composition 60 is selected so that the refractive index of first lens layer 140 is higher than the refractive index of second lens layer 150. When the plurality of microlenses 160 formed in first lens layer 140 are concave lenses, uncured resin composition 60 is selected so that the refractive index of first lens layer 140 is lower than the refractive index of second lens layer 150.

[0127] Next, the surface 142a of the first lens layer 140 of the laminate 70 is opposed to the uncured resin composition 60 formed on the base material layer 170, and the base material layer 170 and the laminate 70 are brought close to each other, so that the uncured resin composition 60 is spread between the base material layer 170 and the first lens layer 140 of the laminate 70. As a result, an uncured resin layer 62 is formed between the base material layer 170 and the first lens layer 140 of the laminate 70, and the base material layer 170 and the laminate 70 are bonded together by the uncured resin layer 62. Then, the uncured resin layer 62 is cured, so that the cured uncured resin layer 62 forms the second lens layer 150, and another surface-emitting device 100 according to this embodiment is manufactured.

[0128] Thus, as shown in Figures 17 and 18, the first lens layer 140 of the lens layer 130 of another surface-emitting device 100 is laminated on the protective layer 120, the second lens layer 150 of the lens layer 130 is laminated on the first lens layer 140, and the base layer 170 is laminated on the second lens layer 150 of the lens layer 130.

[0129] In this case, the protective layer 120 itself may be directly processed to produce the laminate 70 in which a plurality of microlenses 160 are formed on the surface of the protective layer 120 .

[0130] In S115, it is preferable that the diffusion plate 50 or the laminate 70 is manufactured so that the microlenses 160 are convex lenses, which can improve the ease of manufacturing the master disc.

[0131] <9. Application examples of surface-emitting devices> Next, application examples of the surface emitting device 100 according to this embodiment will be described.

[0132] The surface-emitting device 100 as described above can be used as various devices depending on the wavelength of light emitted by each of the multiple light-emitting elements 112. For example, a display device including the surface-emitting device 100 can be made by regularly arranging three light-emitting elements 112, namely, a light-emitting element 112 that emits "R" light, a light-emitting element 112 that emits "G" light, and a light-emitting element 112 that emits "B" light.

[0133] The surface emitting device 100 can also be used as a laser light source device, a lighting device, or a black light.

[0134] <10. Summary> The surface-emitting device 100 according to the present embodiment has been described above. According to the present embodiment, a surface-emitting device 100 is provided that includes a light-emitting section 110 having a plurality of light-emitting elements 112 regularly arranged on a light-emitting surface 110a, a protective layer 120 laminated on the light-emitting section 110, a lens layer 130 laminated on the protective layer 120 and having a plurality of convex or concave microlenses 160 formed therein, and a base material layer 170 laminated on the lens layer 130, in which the plurality of microlenses 160 are irregularly arranged on an XY plane parallel to the light-emitting surface 110a, and when the plurality of light-emitting elements 112 and the plurality of microlenses 160 are projected onto the XY plane, the plurality of microlenses are irregularly arranged on the XY plane such that at least a portion of at least four or more microlenses 160 overlaps with one light-emitting element 112. This makes it possible to suppress a decrease in light extraction efficiency without aligning (positioning) the microlenses 160 and the light-emitting elements 112 with high accuracy.

[0135] Moreover, in this embodiment, the light emitting element 112 has a rectangular planar shape, and the diameter of an inscribed circle 166 inscribed in the opening shape of each microlens 160 is preferably 55% or less of the short side of the light emitting element 112. This makes it possible to easily arrange at least four or more microlenses 160 so that at least a portion of each of the light emitting elements 112 overlaps with each other on the projection surface 114. Therefore, it is possible to further suppress the decrease in light extraction efficiency without aligning the microlenses 160 and the light emitting element 112 with high accuracy.

[0136] In addition, in this embodiment, the lens layer 130 is preferably composed of a first lens layer 140 having a concave-convex structure formed of a plurality of microlenses 160 on its surface 142a, and a second lens layer 150 covering the concave-convex structure on the surface 142a of the first lens layer 140 in order to flatten the concave-convex structure of the first lens layer 140. This makes it easy to realize a three-dimensional surface structure of a highly irregular microlens array, so that the overlapping state of the phases of the diffused light emitted from each microlens 160 can be controlled. Therefore, it is possible to reduce unevenness in the intensity distribution of the diffused light due to interference and diffraction of the diffused light emitted from the plurality of microlenses 160, and to distribute the diffused light uniformly. As a result, it is possible to control the cutoff property of the intensity distribution of the diffused light while having a high transmittance luminance characteristic and satisfying the uniformity of the light distribution of the diffused light.

[0137] In this embodiment, second lens layer 150 of lens layer 130 is laminated on protective layer 120, first lens layer 140 of lens layer 130 is laminated on second lens layer 150, and base layer 170 is laminated on first lens layer 140 of lens layer 130, and a plurality of microlenses 160 formed in first lens layer 140 are concave lenses recessed toward base layer 170, and it is preferable that the refractive index of first lens layer 140 is lower than the refractive index of second lens layer 150. This allows first lens layer 140 to efficiently focus light emitted from second lens layer 150 on the surface 142b side of first lens layer 140.

[0138] In this embodiment, second lens layer 150 of lens layer 130 is laminated on protective layer 120, first lens layer 140 of lens layer 130 is laminated on second lens layer 150, and base layer 170 is laminated on first lens layer 140 of lens layer 130, and a plurality of microlenses 160 formed in first lens layer 140 are convex lenses protruding toward protective layer 120, and it is preferable that the refractive index of first lens layer 140 is higher than the refractive index of second lens layer 150. This allows first lens layer 140 to efficiently focus light emitted from second lens layer 150 on the surface 142b side of first lens layer 140.

[0139] In this embodiment, first lens layer 140 of lens layer 130 is laminated on protective layer 120, second lens layer 150 of lens layer 130 is laminated on first lens layer 140, and base layer 170 is laminated on second lens layer 150 of lens layer 130, and a plurality of microlenses 160 formed in first lens layer 140 are convex lenses protruding toward base layer 170, and it is preferable that the refractive index of first lens layer 140 is higher than the refractive index of second lens layer 150. This allows first lens layer 140 to efficiently collect light emitted from protective layer 120 on the surface 142b side of first lens layer 140.

[0140] In this embodiment, first lens layer 140 of lens layer 130 is laminated on protective layer 120, second lens layer 150 of lens layer 130 is laminated on first lens layer 140, and base layer 170 is laminated on second lens layer 150 of lens layer 130, and a plurality of microlenses 160 formed in first lens layer 140 are concave lenses recessed toward protective layer 120, and it is preferable that the refractive index of first lens layer 140 is lower than the refractive index of second lens layer 150. This allows first lens layer 140 to efficiently collect light emitted from protective layer 120 on the surface 142b side of first lens layer 140.

[0141] Moreover, in this embodiment, the refractive index of lens layer 130 is preferably lower than the refractive index of protective layer 120. This allows most of the light emitted from light emitting section 110 and passing through protective layer 120 to be extracted in the front direction through lens layer 130.

[0142] In this embodiment, the refractive index of the base layer 170 is preferably lower than the refractive index of the protective layer 120. This allows most of the light emitted from the light emitting section 110 and passing through the protective layer 120 to be extracted in the front direction through the base layer 170.

[0143] In this embodiment, it is preferable that the lens layer 130 has no flat portion at the boundary between adjacent microlenses 160. This makes it possible to suppress the zero-order transmitted light component of the incident light from the second lens layer 150.

[0144] In this embodiment, it is preferable that the light emitting section 110, the protective layer 120, the lens layer 130, and the base layer 170 are directly laminated in this order. This allows most of the light emitted from the light emitting section 110 to be efficiently extracted in the front direction through the base layer 170.

[0145] In the present embodiment, the light-emitting element 112 is preferably an organic EL element. This allows the thickness of the surface-emitting device 100 to be thin. In addition, the surface-emitting device 100 can be made flexible. In addition, the surface-emitting device 100 can omit a backlight. Furthermore, the surface-emitting device 100 can have high contrast and color reproducibility. In addition, the surface-emitting device 100 can reduce energy consumption. EXAMPLES

[0146] Next, a surface emitting device according to an embodiment of the present invention will be described. Note that the following embodiment is merely an example for illustrating the effects and feasibility of the surface emitting device according to the present invention, and the present invention is not limited to the following embodiment.

[0147] A ray tracing simulation was performed using a model of the surface-emitting device 100. As the surface-emitting device 100, a model including a light-emitting section 110, a protective layer 120, a lens layer 130, and a base layer 170 was assumed.

[0148] The light-emitting unit 110 had one light-emitting element 112. A Lambertian radiation surface light source made of an organic EL material was assumed as the light-emitting element 112. The shape of the light-emitting element 112 was a square planar shape. The thickness of the light-emitting element 112 was set to zero, and the size was set to 20 [μm] × 20 [μm].

[0149] The protective layer 120 is laminated directly on the light emitting section 110 (light emitting element 112), and light having Lambertian characteristics is emitted from the light emitting element 112 into the protective layer 120. In addition, silicon nitride (refractive index n1=1.9) is set as the material of the protective layer 120, and the thickness is set to 1 [μm].

[0150] The lens layer 130 was made up of a first lens layer 140 and a second lens layer 150. A UV curable resin (refractive index n2=1.7) was used as the material for the second lens layer 150. A plurality of concave microlenses 160 recessed toward the base layer 170 were formed in the first lens layer 140. A UV curable resin (refractive index n3=1.5) was used as the material for the first lens layer 140. The thickness of the lens layer 130 was set to 15 [μm], and the size was set to 400 [μm]×400 [μm].

[0151] The aperture width D of each microlens 160 formed inside the lens layer 130 was irregularly varied within a range of about ±10% with respect to a reference aperture width Dk. Similarly, the curvature radius R of each microlens 160 was irregularly varied within a range of about ±10% with respect to a reference curvature radius Rk. Furthermore, the multiple microlenses 160 were irregularly arranged on an XY plane parallel to the light emitting surface 110a. The filling rate of the microlenses 160 was set to 100%. The surface shape of the microlenses 160 was a spheroid with the planar shape (circle) of the microlenses 160 as the bottom and the lens sag as the height.

[0152] The base material layer 170 was laminated directly on the first lens layer 140. The material of the base material layer 170 was set to PET (refractive index=1.6), and the thickness was set to 100 μm.

[0153] Using a model of the surface-emitting device 100 configured in this manner, the effect of the microlens 160, the change in emission efficiency and change in front brightness due to the relative positional shift of the lens layer 130 with respect to the light-emitting element 112, and the change in emission efficiency due to the aspect ratio (lens opening / sag) were confirmed by simulation.

[0154] <Angle Dependence of Emitted Light with and without Microlens 160> As examples 1 and 2, a simulation was performed on the profile of emitted light when lens layer 130 was laminated on light emitting element 112. As a comparative example, a simulation was performed on the profile of emitted light when lens layer 130 was not laminated on light emitting element 112.

[0155] In the microlens 160 of the first embodiment, the aperture size Sm was set to 6.0 [μm] and the lens sag was set to 2.8 [μm]. In the microlens 160 of the second embodiment, the aperture size Sm was set to 7.5 [μm] and the lens sag was set to 3.5 [μm].

[0156] Fig. 19 shows the simulation results of Example 1 and Comparative Example. Fig. 20 shows the simulation results of Example 2 and Comparative Example. In Fig. 19 and Fig. 20, the vertical axis indicates the intensity [W / str] of the emitted light (light power per unit solid angle), and the horizontal axis indicates the emission angle.

[0157] 19 and 20, in the comparative example not including the lens layer 130, a part of the light emitted from the light emitting element 112 is trapped inside the protective layer 120 having a high refractive index, and propagates in the XY directions. For this reason, it can be seen that in the comparative example, less light is emitted in the front direction (±90 degrees or less).

[0158] In contrast, in Example 1 and Example 2, which include lens layer 130, it was confirmed that the emission profile of the light emitted from light emitting element 112 changed, and more light was emitted in the front direction (±90 degrees or less) than in the comparative example. From this result, it was found that microlens 160 can reduce the confinement of light (waveguide mode loss) inside protective layer 120 and increase the light emitted in the front direction.

[0159] <Effect of difference in aperture size Sm of microlens 160 on position deviation> The microlenses 160 of Examples 3 to 6 were set. The lens layer 130 on which the microlenses 160 of Examples 3 to 6 were formed was moved in the X direction or Y direction from a reference position with respect to the light emitting surface 110a (XY plane) of the light emitting element 112, and the emission efficiency and the front brightness were simulated. The emission efficiency indicates the ratio of the total light intensity [W / str] emitted from the light emitting element 112 to the total light intensity [W / str] radiated in a range of ±45 degrees with the normal line of the light emitting element 112 as an axis. The emission efficiency indicates the intensity of light emitted approximately in the front direction. The front brightness is the intensity [W / str] of light emitted in the normal direction of the light emitting element 112. The positional deviation from the reference position (0 [μm]) was set to 3 [μm], 5 [μm], 8 [μm], and 11 [μm].

[0160] In Example 3, the opening size Sm was set to 6.0 [μm]. In Example 4, the opening size Sm was set to 10.5 [μm]. In Example 3, the opening size Sm was set to 12.0 [μm]. In Example 3, the opening size Sm was set to 13.0 [μm].

[0161] Fig. 21 shows the simulation results of the output efficiency of Examples 3 to 6. Fig. 22 shows the simulation results of the front luminance of Examples 3 to 6. In Figs. 21 and 22, the horizontal axis indicates the moving distance [μm]. In Fig. 21, the vertical axis indicates the output efficiency. In Fig. 22, the vertical axis indicates the front luminance [W / str].

[0162] As shown in FIG. 21, in Example 3 (aperture size Sm = 6.0 [μm]), Example 4 (aperture size Sm = 10.5 [μm]), and Example 5 (aperture size Sm = 12.0 [μm]), it was confirmed that the emission efficiency hardly changed regardless of the movement distance.

[0163] On the other hand, in Example 6 (opening size Sm=13.5 μm), it was confirmed that the emission efficiency increased as the movement distance increased.

[0164] As shown in FIG. 22, in Example 3 (opening size Sm=6.0 μm) and Example 4 (opening size Sm=10.5 μm), it was confirmed that the front luminance hardly changed regardless of the movement distance.

[0165] On the other hand, in Example 5 (opening size Sm=12.0 [μm]) and Example 6 (opening size Sm=13.5 [μm]), it was confirmed that the front luminance varied by moving from the reference position (0 [μm]).

[0166] From the above results, it was found that by setting the aperture size Sm of the microlens 160 to 10.5 [μm] or less for the light emitting element 112 of 20 [μm] × 20 [μm], the emission efficiency and front luminance hardly change even if the lens layer 130 is misaligned with respect to the light emitting element 112. As a result, it was confirmed that by setting the aperture size Sm of the microlens 160 to 55% or less of the short side of the light emitting element 112, the emission efficiency, front luminance, and radiance distribution can be made uniform without aligning the microlens 160 and the light emitting element 112 with high accuracy.

[0167] <Effect of lens sag on output efficiency of Micro Lens 160> The microlenses 160 of Examples 7 to 10 were set. The emission efficiency was simulated when the lens sag (the height of the apex of the lens) of the microlenses 160 of Examples 7 to 10 was changed.

[0168] In Example 7, the opening size Sm was set to 6.0 [μm]. In Example 8, the opening size Sm was set to 7.5 [μm]. In Example 9, the opening size Sm was set to 9.0 [μm]. In Example 10, the opening size Sm was set to 10.5 [μm].

[0169] Fig. 23 shows the results of a simulation of the output efficiency due to differences in lens sag in Examples 7 to 10. Fig. 24 shows the results of a simulation of the output efficiency due to differences in aspect ratio in Examples 8 and 9. In Figs. 23 and 24, the vertical axis indicates the output efficiency. In Fig. 23, the horizontal axis indicates the lens sag [μm]. In Fig. 24, the vertical axis indicates the aspect ratio. The aspect ratio is the ratio of the aperture size Sm to the lens sag (lens sag / aperture size Sm).

[0170] 23, it was confirmed that the output efficiency improves as the lens sag increases, regardless of the aperture size Sm. This shows that if the lens sag (=height) of the microlens 160 is small, the bending performance of the lens decreases, and the effect of improving the output efficiency by the microlens 160 decreases.

[0171] 24, it was confirmed that the output efficiency increases as the aspect ratio increases, regardless of the aperture size Sm. For example, when the aspect ratio is 0.8 or more, the output efficiency is 16% or more, which is an improvement over the output efficiency (14%) in the case where the lens layer 130 is not provided.

[0172] In order to reduce the change in the radiation characteristics of the light emitted from the light emitting element 112 caused by the relative positional deviation between the light emitting element 112 and the microlens 160, it is preferable that the aperture size Sm of the microlens 160 is small. However, if the aperture size Sm of the microlens 160 is made too small, the lens shape may become "rounded" due to the constraints of the manufacturing process of the first lens layer 140 (microlens array), and deviation from the designed shape may easily occur. For this reason, the aperture size Sm of the microlens 160 is preferably 7.5 [μm] or more. For this reason, it has been confirmed that the lens sag of the microlens 160 is preferably 6.0 [μm] or more due to the aspect ratio requirement.

[0173] Although the preferred embodiment of the present invention has been described in detail above with reference to the accompanying drawings, the present invention is not limited to such an example. It is clear that a person having ordinary knowledge in the technical field to which the present invention pertains can conceive of various modified or altered examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present invention. [Explanation of symbols]

[0174] 100 Surface-emitting device 110 Light emitting part 110a Light emitting surface 112 Light emitting element 114 Projection plane 120 protective layer 130 Lens Layer 140 First lens layer 142a surface 150 Second lens layer 160 Micro Lens 170 Base material layer

Claims

1. a light-emitting section having a plurality of light-emitting elements regularly arranged on a light-emitting surface; A protective layer laminated on the light-emitting portion; a lens layer laminated on the protective layer and having a plurality of convex or concave microlenses formed therein; A substrate layer laminated on the lens layer; Equipped with the plurality of microlenses are irregularly arranged on an XY plane parallel to the light emitting surface, A surface-emitting device, wherein the plurality of microlenses are irregularly arranged on the XY plane so that when the plurality of light-emitting elements and the plurality of microlenses are projected onto the XY plane, at least a portion of at least four or more of the microlenses overlaps with one light-emitting element.

2. The light emitting element has a rectangular planar shape, The surface emitting device according to claim 1 , wherein a diameter of an inscribed circle inscribed in the aperture shape of each of the microlenses is 55% or less of a short side of the light emitting element.

3. The lens layer is a first lens layer having a concave-convex structure formed on a surface thereof and including the plurality of microlenses; a second lens layer covering the uneven structure of the surface of the first lens layer to flatten the uneven structure of the first lens layer; 3. The surface emitting device according to claim 1, comprising:

4. the second lens layer of the lens layer is laminated on the protective layer; The first lens layer of the lens layer is laminated on the second lens layer, the substrate layer is laminated on the first lens layer of the lens layer; the plurality of microlenses formed in the first lens layer are concave lenses recessed toward the base layer; The surface emitting device of claim 3 , wherein the refractive index of the first lens layer is lower than the refractive index of the second lens layer.

5. the second lens layer of the lens layer is laminated on the protective layer; The first lens layer of the lens layer is laminated on the second lens layer, the substrate layer is laminated on the first lens layer of the lens layer; the plurality of microlenses formed in the first lens layer are convex lenses protruding toward the protective layer, The surface emitting device of claim 3 , wherein the refractive index of the first lens layer is higher than the refractive index of the second lens layer.

6. the first lens layer of the lens layer is laminated on the protective layer; The second lens layer of the lens layer is laminated on the first lens layer, the substrate layer is laminated on the second lens layer of the lens layer; the plurality of microlenses formed in the first lens layer are convex lenses protruding toward the base layer; The surface emitting device of claim 3 , wherein the refractive index of the first lens layer is higher than the refractive index of the second lens layer.

7. the first lens layer of the lens layer is laminated on the protective layer; The second lens layer of the lens layer is laminated on the first lens layer, the substrate layer is laminated on the second lens layer of the lens layer; the plurality of microlenses formed in the first lens layer are concave lenses recessed toward the protective layer, The surface emitting device of claim 3 , wherein the refractive index of the first lens layer is lower than the refractive index of the second lens layer.

8. The surface emitting device according to claim 1 , wherein the lens layer has a refractive index lower than a refractive index of the protective layer.

9. The surface emitting device according to claim 1 , wherein the refractive index of the base layer is lower than the refractive index of the protective layer.

10. The surface emitting device according to claim 1 , wherein no flat portion exists at boundaries between the plurality of adjacent microlenses.

11. The surface emitting device according to claim 1 , wherein the light emitting portion, the protective layer, the lens layer, and the base layer are directly laminated in this order.

12. The surface emitting device according to claim 1 , wherein the light emitting element is an organic electroluminescence (EL) element.

13. A display device comprising the surface emitting device according to claim 1 .

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