Display device and method for manufacturing display device

Abstract

A display device (1) is provided with a first substrate (2), an insulating material (3), a light-emitting element (4), and a translucent material (5). The insulating material has an opening (OP), and the light-emitting element is positioned inside the opening. The translucent material is positioned on the light extraction side of the light-emitting element, and a part of the translucent material is positioned inside the opening. The display device has a gap (GA) between an inner surface (32) of the opening and the translucent material.

Description

Display device and method for manufacturing the same

[0001] The present disclosure relates to a display device including a light-emitting element and a method for manufacturing the display device.

[0002] Patent Document 1 describes that in a display device including a light-emitting element, a tapered reflector is formed on the light-emitting element in order to improve the efficiency of extracting light from the light-emitting element. Patent Document 1 describes that the efficiency of extracting light from the light-emitting element is improved by internally reflecting the light from the light-emitting element in the tapered reflector.

[0003] Japan Special Table No. 2019-519814

[0004] When an optical member having a high refractive index, such as the tapered reflector described in Patent Document 1, is formed on each light-emitting element, it becomes difficult to align the optical member with the light-emitting element.

[0005] A display device according to one aspect of the present disclosure comprises a first substrate, an insulating material located on the first substrate and having an opening, a light-emitting element located inside the opening, and a translucent material located on the light extraction side of the light-emitting element and with a portion located inside the opening, and has a gap between the inner surface of the opening and the translucent material.

[0006] A method for manufacturing a display device according to one aspect of the present disclosure includes preparing a first substrate, preparing a second substrate that is different from the first substrate and has light-transmitting properties, depositing an insulating material on the first substrate, forming an opening in the insulating material, forming a light-emitting element inside the opening, forming a light-transmitting material on the second substrate, the light-transmitting material having a higher refractive index than the second substrate, and arranging the light-transmitting material on the light-extraction side of the light-emitting element by bonding the first substrate and the second substrate together, wherein the arranging of the light-transmitting material includes arranging the light-transmitting material so that a portion of the light-transmitting material is located inside the opening and there is a gap between the inner surface of the opening and the light-transmitting material.

[0007] In the manufacturing process of a display device, the alignment of a light-transmitting material with respect to a light-emitting element is facilitated, the manufacturing process is simplified, and the yield is improved.

[0008] 1 is a schematic side cross-sectional view of a display device according to Embodiment 1. FIG. 2 is a schematic plan view of a display device according to Embodiment 1. FIG. 3 is an enlarged plan view of a display device according to Embodiment 1. FIG. 4 is a flowchart showing a manufacturing method of a display device according to Embodiment 1. FIG. 5 is a process cross-sectional view showing a manufacturing method of a display device according to Embodiment 1. FIG. 6 is another process cross-sectional view showing a manufacturing method of a display device according to Embodiment 1. FIG. 7 is another process cross-sectional view showing a manufacturing method of a display device according to Embodiment 1. FIG. 8 is a process cross-sectional view showing alignment of a light-transmitting material with respect to a light-emitting element in a manufacturing method of a display device according to Embodiment 1. FIG. 9 is a graph showing the relationship between the taper angle of the side surface of the light-transmitting material and the light extraction efficiency from the light-emitting element in the display devices according to each of Examples 1 to 3. FIG. 10 is a graph showing the relationship between the taper angle of the side surface of the light-transmitting material and the front brightness in the display devices according to each of Examples 1 to 3. FIG. 11 is a schematic side cross-sectional view of a display device according to Embodiment 2. FIG. 12 is a schematic side cross-sectional view of a second substrate for explaining scattering of light in a light-scattering layer according to Embodiment 2. FIG. 13 is a graph showing the relationship between the light scattering intensity in the light-transmitting material and the light extraction efficiency and front brightness from the light-emitting element in a display device according to Example 4. FIG. 14 is a graph showing the relationship between the taper angle of the side surface of the light-transmitting material and the front brightness in the display devices according to Examples 3 and 4. FIG. 15 is an enlarged plan view of a display device according to Embodiment 3. Fig. 1 is an enlarged plan view of a display device according to embodiment 4. Fig. 2 is a schematic diagram showing an example of the shape of the outer edge of an opening according to each embodiment. Fig. 3 is a graph showing the relationship between the thickness of a light-transmitting material and the efficiency of extracting light from a light-emitting element in display devices according to each of examples 5 to 8. Fig. 4 is a graph showing the relationship between the thickness of a light-transmitting material and the dimensions of the outer edge of an opening in display devices according to each of examples 5 to 8.

[0009] [Embodiment 1] <Display Device: Overview> Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that in each drawing, similar components are denoted by the same reference numerals and description thereof will be omitted.

[0010] FIG. 2 is a schematic plan view of a display device 1 according to this embodiment. The display device 1 is a device that can be used, for example, as a display for a television or a smartphone. The display device 1 includes a display unit DA and a frame unit NA formed around the periphery of the display unit DA. The display device 1 displays an image on the display unit DA by controlling light emission from each of a plurality of light-emitting elements (described later) formed in the display unit DA. Drivers and the like for driving each of the plurality of light-emitting elements of the display unit DA may be formed in the frame unit NA.

[0011] Details of the display device 1 according to this embodiment will be described with reference to Fig. 3. Fig. 3 is an enlarged plan view of the display unit DA of the display device 1, particularly an enlarged plan view of region E shown in Fig. 2. Note that the enlarged plan views of the display unit DA of the display device 1 in this disclosure, including Fig. 3, show the second substrate 6 and second electrode 43 (described later) in a see-through manner in order to more clearly show each component. Furthermore, in the enlarged plan view of the display unit DA of the display device 1, some of the components located further back than the components located in the foreground as viewed from the page are indicated by dotted or dashed lines.

[0012] 3, the display unit DA of the display device 1 according to this embodiment includes a plurality of subpixels SP, including red, green, and blue subpixels. A light-emitting element (described later) is formed in each subpixel SP, and each light-emitting element individually emits light. This allows the display device 1 to display an image by individually controlling the emission of light from the plurality of light-emitting elements in the display unit DA using, for example, a driver or the like formed in the frame portion NA.

[0013] 3, the subpixels SP are arranged in rows and columns. In particular, the subpixels SP may be arranged in a direction along each side of the display area DA. However, the positions of the subpixels SP are not limited to this, and adjacent subpixels SP in the row direction may be shifted in the column direction.

[0014] <Display Device: Stacked Structure> The structure of the display device 1, particularly the light-emitting elements provided in the display device 1 and the surrounding structure thereof, will be described in more detail with reference to Fig. 1. Fig. 1 is a schematic side cross-sectional view of the display unit DA of the display device 1, particularly a cross-sectional view taken along line II shown in Fig. 3, and is also a diagram showing a side cross-section passing through the light-emitting elements described below.

[0015] The display device 1 includes a first substrate 2, an insulating material 3, a light-emitting element 4, a light-transmitting material 5, and a second substrate 6. In this disclosure, unless otherwise specified, the direction from the first substrate 2 to the second substrate 6 of the display device 1 will be referred to as the "upward direction," and the direction opposite to the upward direction will be referred to as the "downward direction."

[0016] <Display Device: First Substrate> The first substrate 2 is formed across the display area DA and the frame area NA and includes a rigid substrate such as a glass substrate. The first substrate 2 may include, for example, pixel circuits including thin film transistors for individually controlling light-emitting elements corresponding to each subpixel SP. The first substrate 2 may also include a moisture-proof layer or the like for reducing the penetration of foreign matter such as moisture into the interior of the display device 1.

[0017] <Display Device: Insulating Material> The insulating material 3 is formed on the first surface 21 of the first substrate 2, which is the upper surface of the first substrate 2 in the display device 1, and may contain, for example, a resin having insulating properties such as polyimide, or silicon nitride (SiN ｘ ), silicon oxide (SiO ２ A part of the insulating material 3 is also formed at a position covering an end 41E of a first electrode 41 of the light-emitting element 4 described later. In other words, the insulating material 3 also functions as an edge cover for the light-emitting element 4.

[0018] The insulating material 3 has a plurality of openings OP. The openings OP are formed for each sub-pixel SP. The openings OP have, as their inner side surfaces, tapered surfaces 32 that slope from the upper surface 31 of the insulating material 3 toward the first substrate 2. The tapered surfaces 32 are located from the upper surface 31 of the insulating material 3 to the upper surface 41T of the first electrode 41 (described later), and form an outer edge 33 that is part of the outer edge of the openings OP at the upper surface 41T of the first electrode 41. In other words, the outer edge 33 is located on the first substrate 2 side of the openings OP. In this embodiment, the outer edge 33 has a circular shape in a plan view. Inside the outer edge 33, the surface of the first electrode 41, particularly the upper surface 41T, is exposed from the insulating material 3.

[0019] <Display Device: Light-Emitting Element> The light-emitting element 4 includes, in order from the first substrate 2 side, a first electrode 41, a light-emitting layer 42, and a second electrode 43. As described below, the first electrode 41 and the light-emitting layer 42 are formed in an island shape for each subpixel SP, and the second electrode 43 is formed common to multiple subpixels SP. The display device 1 includes a light-emitting element 4 including the first electrode 41, the light-emitting layer 42, and the second electrode 43 at a position overlapping each subpixel SP in a planar view. The light-emitting element 4 may further include a functional layer such as a charge transport layer between the first electrode 41 and the light-emitting layer 42 or between the light-emitting layer 42 and the second electrode 43. For example, as described below, the first electrode 41 is an anode and the second electrode 43 is a cathode. In this case, the light-emitting element 4 may include, in this order from the first substrate 2 side, the first electrode 41, a hole injection layer, a hole transport layer, the light-emitting layer 42, an electron transport layer, an electron injection layer, and the second electrode 43. The charge transport layer between the light-emitting layer 42 and the second electrode 43 may be only an electron injection layer.

[0020] The first electrodes 41 are located on the first surface 21 of the first substrate 2 and are formed in an island shape for each subpixel SP. Each first electrode 41 is connected to a pixel circuit (not shown) that the first substrate 2 has for each subpixel SP via a contact hole or the like formed in the first substrate 2. A voltage is applied to each first electrode 41 individually via a pixel circuit driven by a driver or the like. The first electrode 41 may be a reflective electrode and may contain, for example, Al, Cu, Au, Ag, or Mg alone or an alloy of these, which have high reflectivity for visible light. The first electrode 41 may also be an anode.

[0021] The light-emitting layer 42 is located on the upper surface 41T of the first electrode 41 and inside the opening OP. In other words, it is formed in an island shape for each subpixel SP. The light-emitting layer 42 includes a light-emitting material that emits light by excitons generated upon recombination of charges injected from each electrode by a method described below. The light-emitting layer 42 may include, as the light-emitting material, an organic light-emitting material such as an organic fluorescent material or an organic phosphorescent material, or an inorganic light-emitting material such as luminescent semiconductor nanoparticles, in other words, quantum dots. The light-emitting layer 42 may be formed to be larger than the outer edge 33 in a planar view. In particular, all layers of the light-emitting element 4, including the light-emitting layer 42, may be located on the first electrode 41 exposed through the opening OP. This prevents chipping of layers constituting the light-emitting element 4 at positions overlapping the first electrode 41 in a planar view, thereby suppressing a decrease in the light-emitting efficiency of the light-emitting element 4 due to current leakage.

[0022] The second electrode 43 faces the first electrode 41 via a functional layer including the light-emitting layer 42 and is formed at a position overlapping the light-emitting layer 42 at least in a planar view. For example, the second electrode 43 is formed commonly to a plurality of subpixels SP, and is particularly formed at a position overlapping the light-emitting layer 42, the upper surface 31 of the insulating material 3, and the tapered surface 32 of the insulating material 3 in a planar view. The second electrode 43 may be connected to an auxiliary power source (not shown) or the like, and a predetermined voltage may be applied to the second electrode 43. The second electrode 43 is a transparent electrode and may include, for example, a transparent conductor such as an oxide conductor, or a metal thin film thin enough to transmit visible light. The second electrode 43 may also include a laminate of the above-mentioned transparent conductor and a metal thin film, such as an ITO / Ag / ITO laminate film, or may have a structure in which a light-transmitting dielectric layer is laminated on a metal thin film. The second electrode 43 may be a cathode.

[0023] The display device 1 applies a voltage to each first electrode 41 individually and applies a predetermined voltage to the second electrode 43, thereby generating a potential difference between the first electrode 41 and the second electrode 43 of each light-emitting element 4. The generation of a potential difference between the first electrode 41 and the second electrode 43 causes electrons and holes to be injected from the first electrode 41 and the second electrode 43 toward the light-emitting layer 42. For example, the first electrode 41 may be an anode that injects holes into the light-emitting layer 42, and the second electrode 43 may be a cathode that injects electrons into the light-emitting layer 42. The electrons and holes injected into the light-emitting layer 42 recombine to generate excitons, and the excitons cause the light-emitting material in the light-emitting layer 42 to emit light.

[0024] A portion of the light from the light-emitting layer 42 is emitted toward the second electrode 43 and passes through the second electrode 43. A portion of the light from the light-emitting layer 42 is emitted toward the first electrode 41, is reflected by the upper surface 41T of the first electrode 41, and then passes through the second electrode 43. As a result, the light from the light-emitting layer 42 is extracted to the outside of the light-emitting element 4 from the second electrode 43 side of the light-emitting element 4.

[0025] The light-emitting element 4 includes a first electrode 41, a light-emitting layer 42, and a second electrode 43 at a position overlapping with the subpixel SP in a planar view. Furthermore, a portion of the first electrode 41 including an end portion 41E is covered with an insulating material 3, and the portions of the light-emitting layer 42 and the second electrode 43 that overlap with the first electrode 41 in a planar view are all located inside the opening OP. Therefore, in this embodiment, the light-emitting element 4 can be considered to be located inside the opening OP. Furthermore, in this embodiment, the display device 1 includes a light-emitting element 4 inside each of a plurality of openings OP, in other words, the display device 1 includes a plurality of light-emitting elements 4.

[0026] The insulating material 3 prevents a short circuit between the first electrode 41 and the second electrode 43 that occurs as the light-emitting layer 42 of each light-emitting element 4 becomes thinner. Furthermore, by covering the end 41E of the first electrode 41, the insulating material 3 reduces the effect of electric field concentration at the end 41E on charge injection into the light-emitting layer 42 when the light-emitting element 4 is driven. Furthermore, by covering the end 41E of the first electrode 41, the insulating material 3 reduces the generation of stray light associated with light emission from the periphery of the light-emitting element 4 in a planar view. Furthermore, by forming the light-emitting layer 42 inside the opening OP, the display device 1 reduces the propagation of light from the light-emitting layer 42 of a certain subpixel SP to other subpixels SP, thereby reducing the generation of stray light. When the insulating material 3 contains a material that absorbs visible light, such as a black material, the insulating material 3 not only further enhances the stray light reduction effect described above, but also reduces the reflection of external light incident on the display surface from outside the display device 1, thereby improving the visibility of the display surface. In addition, the insulating material 3 containing a material that absorbs visible light reduces the number or thickness of optical layers such as a circular polarizer provided on the light extraction side of the light-emitting element 4 to reduce external light reflection, thereby simplifying the configuration of the display device 1.

[0027] <Display Device: Light-Transmitting Material> The light-transmitting material 5 is located on the light extraction side of the light-emitting element 4, in other words, on the side of the second electrode 43 of the light-emitting element 4, and transmits at least light emitted by the light-emitting layer 42. The light-transmitting material 5 is formed on a second surface 61 of the second substrate 6, which is the lower surface of the second substrate 6 described later in the display device 1. A portion of the light-transmitting material 5 on the side of the first substrate 2 is located inside the opening OP. In particular, the light-transmitting material 5 contacts the second electrode 43 of the light-emitting element 4 inside the opening OP. In this embodiment, the display device 1 includes a light-transmitting material 5 on the light extraction side of each of the multiple light-emitting elements 4, in other words, the display device 1 includes multiple light-transmitting materials 5. The absolute refractive index of the light-transmitting material 5 may be 1.6 or more and 2.0 or less.

[0028] The light-transmitting material 5 has a bottom surface 51 on the side of the light-emitting element 4, an upper surface 52 on the side of the second substrate 6, and an outer surface 53 connecting the bottom surface 51 and the upper surface 52. In this embodiment, the bottom surface 51 and the upper surface 52 are both approximately circular, and the diameter of the bottom surface 51 is smaller than the diameter of the upper surface 52. Therefore, in this embodiment, the light-transmitting material 5 has a truncated cone shape with the bottom surface 51 side as the tip side. In this embodiment, the bottom surface 51 and the upper surface 52 are approximately parallel, and the bottom surface 51 and the second surface 61 of the second substrate 6 are also approximately parallel.

[0029] The tapered surface 32, which forms the inner surface of the opening OP, is spaced from the outer surface 53 of the light-transmitting material 5. Therefore, the display device 1 has a gap GA between the tapered surface 32 and the outer surface 53. In this embodiment, the refractive index of the gap GA is lower than that of the light-transmitting material 5. The gap GA may be a vacuum, or may contain a gas or a low-refractive material, in order to reduce the penetration of foreign matter such as moisture into the light-emitting element 4 and thereby reduce deterioration of the light-emitting element 4. The gas contained in the gap GA may contain a low-reactivity gas such as dry nitrogen, in order to reduce deterioration of the light-emitting element 4. Furthermore, the absolute refractive index of the low-refractive material contained in the gap GA may be 1.2 or more and 1.4 or less. When a low-refractive material is contained in the gap GA, the refractive index of the gap GA can be designed by designing the refractive index of the low-refractive material.

[0030] <Display Device: Second Substrate> The second substrate 6 faces the first substrate 2 and is formed across the display area DA and the frame area NA. The second substrate 6 includes a rigid substrate such as a glass substrate. The second substrate 6 is translucent and transmits at least the light from the light-emitting elements 4. The second substrate 6 may include the same material as the first substrate 2. The first substrate 2 and the second substrate 6 are bonded together via a bonding material (not shown) formed in the frame area NA or the like. The first surface 21 of the first substrate 2 and the second surface 61 of the second substrate 6 are parallel to each other. The refractive index of the second substrate 6 may be lower than the refractive index of the translucent material 5.

[0031] The first surface 21 of the first substrate 2 and the outer side surface 53 of the light-transmitting material 5 form a first angle A1 on the exterior side of the light-transmitting material 5. The first angle A1 corresponds to the taper angle of the side surface of the light-transmitting material 5. Furthermore, the first surface 21 and the tapered surface 32 that forms the inner surface of the opening OP form a second angle A2 on the interior side of the insulating material 3. In this embodiment, the first angle A1 may be larger than the second angle A2. Note that, as described above, the light-transmitting material 5 has a truncated cone shape with its tip facing the first substrate 2, and therefore the first angle A1 is an acute angle.

[0032] In this embodiment, the distance from the first surface 21 to the top surface 52 of the light-transmitting material 5 is defined as distance L1. Distance L1 corresponds to the height from the first surface 21 to the top surface of the light-transmitting material 5. Furthermore, the distance from the first surface 21 to the top surface 31 of the insulating material 3 excluding the opening OP is defined as distance L2. Distance L2 corresponds to the height from the first surface 21 to the top surface of the insulating material 3. From the viewpoint of reducing interference between the insulating material 3 and the second substrate 6, distance L1 is greater than distance L2. Furthermore, the distance from the bottom surface 51 to the top surface 52 of the light-transmitting material 5 is defined as distance L3. Distance L3 corresponds to the thickness of the light-transmitting material 5 in the light emission direction of the light-emitting element 4, in other words, the light extraction direction of the light-emitting element 4.

[0033] In order to more clearly show each part of the display device 1, the dimensions of each part shown in Fig. 1 and the like do not necessarily correspond to the dimensions of each part of the display device according to each embodiment described later. For example, the distance L3 may be larger than that shown in Fig. 1 compared to the dimensions of the opening OP in a plan view.

[0034] <Improvement of Light Extraction Efficiency> The effect of providing the display device 1 with the light-transmitting material 5 on the light extraction side of the light-emitting element 4 will be described with reference to FIG.

[0035] Light extracted from the light-emitting layer 42 of the light-emitting element 4 to the outside of the light-emitting element 4 is incident on the light-transmitting material 5. For example, of the light from the light-emitting layer 42, light LP1 emitted from the light-emitting layer 42 substantially parallel to the stacking direction of the light-emitting element 4 passes through the light-transmitting material 5 and the second substrate 6 in this order, and is extracted to the outside of the display device 1. Light reflected at the interface between the light-transmitting material 5 and the second substrate 6 may be extracted to the outside of the display device 1 by being reflected again by the upper surface 41T of the first electrode 41.

[0036] For example, assume that the light from the light-emitting layer 42 includes light LP2 emitted from the light-emitting layer 42 in a direction intersecting the stacking direction of the light-emitting elements 4. When the light LP2 is reflected at the interface between the light-transmitting material 5 and the second substrate 6, the light LP2 may head toward the outer surface 53 of the light-transmitting material 5. Here, a gap GA is located between the tapered surface 32 and the outer surface 53. Because the gap GA has a lower refractive index than the light-transmitting material 5, the light LP2 propagating toward the outer surface 53 is likely to be totally reflected at the outer surface 53. As a result, the light LP2 totally reflected at the outer surface 53 propagates again toward the second substrate 6 and is extracted to the outside of the display device 1. When the refractive index of the second substrate 6 is lower than that of the light-transmitting material 5, the display device 1 can extract to the outside only the light that is reflected at the outer surface 53 and propagates toward the second substrate 6, but that is incident at a deeper angle with respect to the interface between the light-transmitting material 5 and the second substrate 6. As a result, the display device 1 improves the light extraction efficiency from the light emitting element 4 by the light-transmitting material 5 and also improves the front brightness.

[0037] As described above, the display device 1 including the light-transmitting material 5 increases the intensity of light extracted to the second substrate 6 side from the light-emitting element 4. In particular, by providing the gap GA between the tapered surface 32 and the outer surface 53, the display device 1 further intensifies the light extracted to the outside from the light-emitting element 4. Therefore, the display device 1 further increases the efficiency of extracting light from the light-emitting element 4.

[0038] When the absolute refractive index of the light-transmitting material 5 is 1.6 or higher, the display device 1 increases the difference in refractive index between the light-transmitting material 5 and the gap GA, making it easier for light propagating from the inside of the light-transmitting material 5 toward the outer surface 53 to be totally reflected at the outer surface 53, thereby improving the light extraction efficiency from the light-emitting element 4. When the absolute refractive index of the light-transmitting material 5 is 2.0 or lower, the light-transmitting material 5 can be more easily formed from an existing light-transmitting material with a high refractive index, which is advantageous from the standpoint of facilitating production and reducing costs.

[0039] When the first angle A1 is greater than the second angle A2, in the display device 1, interference between the insulating material 3 and the light-transmitting material 5 can be reduced even when the area of ​​the outer edge 33 of the opening OP in a plan view and the area of ​​the bottom surface 51 of the light-transmitting material 5 are substantially the same. Therefore, from the viewpoint of increasing the contact area between the light-emitting element 4 and the light-transmitting material 5 and allowing more light from the light-emitting element 4 to be incident on the light-transmitting material 5, the first angle A1 may be greater than the second angle A2.

[0040] As described above, the light-transmitting material 5 according to this embodiment has a truncated cone shape. Therefore, the light-transmitting material 5 has a shape symmetrical about its centroid in a planar view. Therefore, the display device 1 including the light-transmitting material 5 according to this embodiment makes it easier to design the light-transmitting material 5 to improve its optical characteristics. Furthermore, since the light-transmitting material 5 has a truncated cone shape, the optical characteristics of the light-transmitting material 5 do not change significantly depending on the orientation from the center of the light-transmitting material 5 in a planar view. Therefore, the display device 1 allows the design of the light-transmitting material 5 to optimize the extraction efficiency regardless of the orientation of light from the light-emitting elements 4, further improving the light extraction efficiency from each light-emitting element 4.

[0041] <Manufacturing Method of Display Device> A manufacturing method of the display device 1 according to this embodiment will be described with reference to Fig. 4 to Fig. 7. Fig. 4 is a flowchart showing the manufacturing method of the display device 1. Fig. 5 to Fig. 7 are cross-sectional views showing steps in the manufacturing method of the display device 1. All of the cross-sectional views in this embodiment show a cross section of the display device 1 at a position corresponding to the cross section of the display device 1 shown in Fig. 1.

[0042] 4 , in the method for manufacturing the display device 1, first, a first substrate 2 is prepared (step S1). In step S1, the first substrate 2 is prepared with its first surface 21 facing upward. In step S1, a large-sized first substrate 2 may be prepared. In this case, in the method for manufacturing the display device 1, the first substrate 2 may be cut together with the second substrate 6 later to separate into individual display devices 1. In step S1, pixel circuits may be formed on the first substrate 2, and contact holes may be formed in the first substrate 2 to realize electrical connection between the pixel circuits and the first electrodes 41 of the light-emitting elements.

[0043] Next, the first electrodes 41 are formed on the first surface 21 of the first substrate 2 (step S2). The first electrodes 41 may be formed by depositing a thin film of a conductive material at a position on the first surface 21 that overlaps the display area DA in a plan view, and then patterning the thin film for each sub-pixel SP by dry etching or the like. In step S2, electrical connection between the pixel circuits of the first substrate 2 and the first electrodes 41 may be achieved by depositing a conductive material in the contact holes formed in the first substrate 2.

[0044] Next, the insulating material 3 is formed. In forming the insulating material 3, first, an insulating material film 34 containing the material of the insulating material 3 is formed on the first surface 21 and the upper surface 41T of the first electrode 41 (step S3). The insulating material film 34 may be formed by applying a material obtained by adding a positive photosensitive resin to polyimide or the like by a spin coating method or the like.

[0045] Next, an opening OP is formed in the insulating material film 34 in a portion that overlaps the first electrode 41 in a plan view (step S4). The opening OP may be formed by patterning using a photolithography method, in which the insulating material film 34 is exposed to light using a photomask and then washed with a developer. A tapered surface 32 is formed in the opening OP by patterning the insulating material film 34, which contains a positive photosensitive resin. Furthermore, in step S4, the opening OP is formed so that the opening OP exposes a portion of the first electrode 41 closer to the center than the end 41E. Therefore, an outer edge 33 of the opening OP is formed on the upper surface 41T of the first electrode 41. In this manner, the insulating material 3 is formed.

[0046] Next, the light-emitting layer 42 is formed (step S5). The light-emitting layer 42 may be formed by applying a light-emitting material to the inside of the opening OP using an inkjet method or the like. Since the light-emitting layer 42 is located inside the opening OP, the light-emitting layer 42 can be formed by applying different colors using an inkjet method or the like. Alternatively, the light-emitting layer 42 may be formed using a vapor deposition method, a lift-off method, a photolithography method, or the like. If the display device 1 includes light-emitting elements that emit different colors of light depending on the subpixel SP, the emission color of the light-emitting layer 42 formed by the subpixel SP may be changed in step S5. Note that a hole injection layer and a hole transport layer may be formed prior to step S5, and an electron transport layer and an electron injection layer may be formed after step S5. The formation of each of the charge transport layers described above may be performed using a conventionally known method.

[0047] Next, the second electrode 43 is formed (step S6). The second electrode 43 may be formed by depositing a thin film of a conductive material on the insulating material 3, including the inside of the opening OP, and on the light-emitting layer 42. As a result of the above, a first stacked body LA1 including each layer from the first substrate 2 to the second electrode 43 is formed. Note that, upon completion of step S6, a light-emitting element 4 including the first electrode 41, the light-emitting layer 42, and the second electrode 43 is formed inside the opening OP. Therefore, steps S2, S5, and S6 are included in the process of forming the light-emitting element 4 inside the opening OP.

[0048] In the manufacturing method of the display device 1 according to this embodiment, aside from forming the first laminate LA1 described above, the second substrate 6 is prepared (step S7). In step S7, the second substrate 6 is prepared with the second surface 61 facing upward.

[0049] Next, a light-transmitting material 5 is formed on the second surface 61 (step S8). The light-transmitting material 5 may be formed, for example, by coating a film of a positive photosensitive resin on the second surface 61, followed by patterning using a photolithography method including exposure using a photomask and development using a developer. By patterning the material including the positive photosensitive resin, a truncated cone-shaped light-transmitting material 5 is formed on the second surface 61, with its tip facing away from the second substrate 6. Therefore, at the completion of step S8, the light-transmitting material 5 has a top surface 52 facing the second substrate 6 and a bottom surface 51 facing away from the second substrate 6. In this way, a second laminate LA2 including the light-transmitting material 5 and the second substrate 6 is formed.

[0050] After steps S6 and S8 are completed, the manufacturing method of the display device 1 according to this embodiment involves bonding the first substrate 2 and the second substrate 6 together (step S9). In step S9, for example, the second stack LA2 is placed with the light-transmitting material 5 facing downward on the first stack LA1 with the second electrode 43 facing upward. The second stack LA2 is then brought close to the first stack LA1, and the light-transmitting material 5 is aligned with the light-emitting element 4 by a method described below. The first substrate 2 and the second substrate 6 are then bonded together with a bonding material (not shown), thereby completing step S9 and the manufacturing method of the display device 1.

[0051] In addition, when the first substrate 2 and the second substrate 6 are bonded together, the light-transmitting material 5 on the second substrate 6 is disposed on the light-emitting element 4, so that the light-transmitting material 5 is placed on the light-extraction side of the light-emitting element 4. In addition, when the first substrate 2 and the second substrate 6 are bonded together, a gap GA is formed between the tapered surface 32 of the insulating material 3 and the outer surface 53 of the light-transmitting material 5. In step S9, the gap GA may be evacuated by bonding the first substrate 2 and the second substrate 6 together in a vacuum. Alternatively, in step S9, the gap GA may be filled with a gas or a low-refractive-index material, and then the gap between the first substrate 2 and the second substrate 6 may be sealed.

[0052] <Alignment of Light-Transmitting Material with Respect to Light-Emitting Element> A method for aligning the light-transmitting material 5 with respect to the light-emitting element 4 in step S9 will be described with reference to Fig. 8. Fig. 8 is a process cross-sectional view showing the method for aligning the light-transmitting material 5 with respect to the light-emitting element 4 in step S9.

[0053] For example, suppose that in step S9, when the first stacked body LA1 and the second stacked body LA2 are brought close to each other, the position of the light-transmitting material 5 relative to the light-emitting element 4 in a planar view is deviated from the appropriate position. Even in this case, as shown in step S9A in Fig. 8 , the light-transmitting material 5 is inserted inside the opening OP as long as the positional deviation of the light-transmitting material 5 relative to the light-emitting element 4 is not extremely large. In other words, the first substrate 2 and the second substrate 6 are bonded together so that at least a portion of the light-transmitting material 5 on the second substrate 6 is located inside the opening OP.

[0054] Therefore, in the display device 1 according to this embodiment, even if the position of the light-transmitting material 5 is misaligned with respect to the light-emitting element 4, the opening OP limits the position of the light-transmitting material 5. Therefore, in the step of installing the light-transmitting material 5 on the light-emitting element 4, the display device 1 makes it easier to align the light-transmitting material 5 with respect to the light-emitting element 4, simplifying the manufacturing process and improving yield. In particular, as shown in step S9A in Figure 8, in step S9 according to this embodiment, the side of the bottom surface 51 of the light-transmitting material 5 abuts against the tapered surface 32 of the opening OP or the second electrode 43 on the tapered surface 32.

[0055] In step S9, the first stacked body LA1 and the second stacked body LA2 are brought closer to each other from the state shown in step S9A due to the weight of the second stacked body LA2 or the like. As a result, the light-transmitting material 5 moves toward the center of the opening OP along the tapered surface 32, as shown in step S9B of Fig. 8. As a result, the position of the light-transmitting material 5 approaches an appropriate position relative to the light-emitting element 4, and therefore alignment of the light-transmitting material 5 with the light-emitting element 4 is achieved.

[0056] In the above-described method, the opening OP and the light-transmitting material 5 are brought into close proximity with each other and the bottom surface 51 of the light-transmitting material 5 abuts against the tapered surface 32, thereby realizing alignment of the light-transmitting material 5 with respect to the light-emitting element 4. Here, when the first angle A1 is greater than the second angle A2, the probability that the light-transmitting material 5 will abut against the tapered surface 32 increases even when there is a large misalignment of the light-transmitting material 5 with respect to the light-emitting element 4. Therefore, from the viewpoint of more appropriately aligning the light-transmitting material 5 with respect to the light-emitting element 4, the first angle A1 may be greater than the second angle A2.

[0057] In this embodiment, the light-transmitting material 5 is located on the second substrate 6. Therefore, in the display device 1 according to this embodiment, the light-transmitting material 5 can be disposed on the light-emitting elements 4 by bonding the first substrate 2 and the second substrate 6 together. Therefore, in the manufacturing method of the display device 1, the light-transmitting material 5 can be disposed on the light-emitting elements 4 in a simpler manner than a method of disposing the light-transmitting material 5 individually on the light-emitting elements 4. Furthermore, in the manufacturing method of the display device 1, the light-transmitting material 5 is formed on the second substrate 6, so that the light-transmitting material 5 can be more easily formed having an outer surface 53 that forms the first angle A1 with the first surface 21 of the first substrate 2.

[0058] In the display device 1 according to this embodiment, another configuration for improving the light extraction efficiency from the light-emitting elements 4 is to extend the first electrode 41 onto the tapered surface 32 of the insulating material 3 to form a reflective film. However, when manufacturing a display device 1 having the above configuration, it is necessary to further form an insulating film or the like to prevent the extended first electrode 41 from shorting with the second electrode 43, which complicates the structure and manufacturing process of the display device 1. By including the light-transmitting material 5 on the second substrate 6 in the display device 1, this embodiment makes it possible to manufacture a display device 1 that improves the light extraction efficiency from each light-emitting element 4 without performing a process such as forming a reflective film on the tapered surface 32.

[0059] <Evaluation of Optical Characteristics of Display Device> Display devices according to Examples 1 to 3 were fabricated, and the optical characteristics of each display device were evaluated.

[0060] The display devices according to each example all have the same configuration as the display device 1 according to this embodiment. In Examples 1, 2, and 3, the distance L3 is 2 μm, 3 μm, and 4 μm, respectively. In each example, the absolute refractive index of the light-transmitting material 5 is 1.8, the absolute refractive index of the second substrate 6 is 1.5, and the diameter of the outer edge 33 in a planar view is 30 μm. The peak wavelength of the light emitted by the light-emitting element 4 according to each example is 455 nm.

[0061] For each of the display devices according to Examples 1 to 3, the optical characteristics were measured by varying the first angle A1 from 20° to 45° in 5° increments. FIGS. 9 and 10 are graphs showing the measured optical characteristics of the display devices according to each Example. FIG. 9 is a graph showing the relationship between the first angle A1 and the light extraction efficiency from the light-emitting element 4 for the display devices according to each Example. In the graph of FIG. 9 , the horizontal axis represents the first angle A1 (unit: °), and the vertical axis represents the light extraction efficiency of the light-emitting element 4 (arbitrary units). FIG. 10 is a graph showing the relationship between the first angle A1 and the front luminance of the display device according to each Example. In the graph of FIG. 9 , the horizontal axis represents the first angle A1 (unit: °), and the vertical axis represents the front luminance (arbitrary units). In the graphs of FIGS. 9 and 10 , the data for Examples 1, 2, and 3 are indicated by dotted lines, dashed lines, and solid lines, respectively.

[0062] The graph in FIG. 9 shows that in each example, the light extraction efficiency from the light-emitting element 4 of each display device is high when the first angle A1 is around 25°, regardless of the distance L3. Furthermore, the graph in FIG. 10 shows that in each example, the front luminance of the display device is high when the first angle A1 is around 35°, regardless of the distance L3. From the perspective of improving the front luminance of the display device 1, the first angle A1 according to this embodiment may be between 30° and 40°. In particular, improving the front luminance of the display device 1 is advantageous from the perspective of reducing the power consumption and extending the life of the display device 1. Furthermore, the graphs in FIGS. 9 and 10 show that in each example, the light extraction efficiency from the light-emitting element 4 of each display device and the front luminance tend to increase as the distance L3 increases.

[0063] [Embodiment 2] <Light scattering layer> A display device according to another embodiment will be described with reference to Fig. 11. Fig. 11 is a schematic side cross-sectional view of a display device 11 according to this embodiment, showing a cross section at the same position as the cross section shown in Fig. 1.

[0064] The display device 11 according to this embodiment has the same configuration as the display device 1 according to the previous embodiment, except that it includes a second substrate 7 instead of the second substrate 6. The second substrate 7 includes a light-transmitting layer 71 and a light-scattering layer 72.

[0065] The light-transmitting layer 71 is, for example, a rigid light-transmitting plate-like member such as a glass substrate, and may contain the same material as the second substrate 6. A light-transmitting material 5 is formed on a second surface 73 of the light-transmitting layer 71 on the first substrate 2 side.

[0066] The light-scattering layer 72 is a plate-like member having both light-transmitting and light-scattering properties, and is formed on the side of the light-transmitting layer 71 opposite the first substrate 2 side. The light-scattering layer 72 may contain, for example, the same material as the light-transmitting layer 71 with light-scattering particles added. The display device 1 may also include a circular polarizer adhered to the display surface side of the second substrate 7. In this case, the light-scattering layer 72 may be an adhesive layer for adhering the circular polarizer to the light-transmitting layer 71, or may contain a material with light-scattering particles added to the adhesive. Alternatively, the light-scattering layer 72 may be formed by polishing the surface of the light-transmitting layer 71 on the display surface side, and may have unevenness formed by the polishing. The light-scattering layer 72 scatters at least light from the light-emitting elements 4.

[0067] <Light Scattering in Light Scattering Layer> The manner in which the light scattering layer 72 scatters light from the light emitting element 4 will be described with reference to Fig. 12. Fig. 12 is a schematic diagram of a cross section of the second substrate 7 for explaining the scattering of light in the light scattering layer 72. In particular, Fig. 12 shows a cross section of the second substrate 7 in the vicinity of an interface 7B between the light transmitting layer 71 and the light scattering layer 72.

[0068] As shown in Fig. 12, assume that light LP3 from the light-emitting element 4 is incident from the light-transmitting layer 71 side of the second substrate 7. In this case, light LP3 is scattered at least on the light-scattering layer 72 side of the interface 7B. For example, as shown in Fig. 12, light LP3 is decomposed into light having components such as light LP5 in addition to light LP4, which has the strongest component. Note that refraction may occur between light LP3 and light LP4 due to the difference in refractive index between the light-transmitting layer 71 and the light-scattering layer 72, and the propagation directions of light LP3 and light LP4 may not coincide.

[0069] In this embodiment, light incident on the light scattering layer 72 is Gaussian scattered. When the angle from the light in the direction of the Gaussian scattered transmitted light is θ, the luminous intensity P(θ) of the light in a direction inclined by θ from the direction of the transmitted light is expressed by the following equation:

[0070] In the above formula, P ０ is the luminous intensity of the transmitted light in the transmitted light direction, and σ is the standard deviation of the Gaussian distribution (unit: °). From the above formula, the larger σ is, the stronger the Gaussian scattering in the light scattering layer 72 is.

[0071] <Evaluation of Display Device Having Light-Scattering Layer> A display device according to Example 4 was fabricated and the optical characteristics of the display device were evaluated.

[0072] The display device according to Example 4 has the same configuration as the display device 11 according to this embodiment. In particular, the display device according to Example 4 has the same configuration as the display device according to Example 3, except that the display device according to Example 4 includes a second substrate 7 instead of the second substrate 6.

[0073] In the display device of Example 4, the optical characteristics were measured by varying the σ value of Gaussian scattering in the light-scattering layer 72 from 0° to 30° in 5° increments. FIG. 13 is a graph showing the relationship between σ and the light extraction efficiency from the light-emitting element 4 and the front luminance of the display device of Example 4. In other words, FIG. 13 is a graph showing the relationship between the light scattering intensity in the light-transmitting material 5 and the light extraction efficiency and front luminance of the light-emitting element 4. In the graph of FIG. 13 , the horizontal axis represents σ (unit: °), the left vertical axis represents the light extraction efficiency from the light-emitting element 4 (arbitrary units), and the right vertical axis represents the front luminance (arbitrary units). In the graph of FIG. 13 , the solid line represents the light extraction efficiency from the light-emitting element 4, and the dotted line represents the front luminance.

[0074] From the graph in Figure 13, it can be seen that in Example 4, the smaller σ is, the higher the light extraction efficiency from the light-emitting element 4 is.Furthermore, from the graph in Figure 13, it can be seen that in Example 4, when σ is around 15°, the front brightness of the display device is high.

[0075] Next, in the display device according to Example 4, the first angle A1 was changed from 20° to 45° in 5° increments, and the front luminance of the display device was measured and compared with that of the display device according to Example 3. FIG. 14 is a graph showing the relationship between the first angle A1 and the front luminance of the display device according to Examples 3 and 4. In the graph of FIG. 14, the horizontal axis represents the first angle A1 (unit: degrees), and the vertical axis represents the front luminance (arbitrary units). In the graph of FIG. 14, the data for Example 3 is shown by a dotted line, and the data for Example 4 is shown by a solid line. In this measurement, the σ value of Gaussian scattering in the light scattering layer 72 of the display device according to Example 4 was set to 15°, at which the front luminance of the display device increased in the above-mentioned measurement.

[0076] 13 shows that the display device according to Example 4 has a relatively high front luminance over a wide range of the first angle A1 from 20° to 40° compared to the display device according to Example 3. From the viewpoint of improving the front luminance of the display device 11, the first angle A1 according to this embodiment may be 20° or more and 40° or less.

[0077] The first angle A1 varies depending on the shape of the light-transmitting material 5. In particular, when the light-transmitting material 5 is manufactured by photolithography or the like, manufacturing errors often occur in the shape of the light-transmitting material 5, and the error in the first angle A1 may become large. The display device 11 according to this embodiment can maintain a relatively high front brightness even when an error occurs in the shape of the light-transmitting material 5 and, as a result, the first angle A1 deviates from the designed value.

[0078] [Embodiment 3] <Another Example of First Electrode> A display device according to another embodiment will be described with reference to Fig. 15. Fig. 15 is an enlarged plan view of the display device 12 according to this embodiment, showing an enlarged view of the same position as that shown in Fig. 3.

[0079] The display device 12 according to this embodiment differs in configuration from the display devices according to the above-described embodiments in that the light-emitting elements 4 include a first electrode 44 instead of the first electrode 41. The first electrode 44 has the same configuration as the first electrode 41 except for its shape in a plan view. The first electrode 44 is formed at a position that overlaps with a plurality of openings OP in a plan view. Therefore, in this embodiment, the first electrode 41 is common to the plurality of light-emitting elements 4.

[0080] In this embodiment, all of the light-emitting elements 4 that share the first electrode 41 are included in the same sub-pixel SP. Note that, although the first electrode 41 is common to three adjacent light-emitting elements 4 in Fig. 15 , this is not limiting, and the first electrode may be common to at least two adjacent light-emitting elements 4.

[0081] Except for the above, the display device 12 according to this embodiment has the same configuration as the display devices according to the above-described embodiments. The display device 12 according to this embodiment can simultaneously drive multiple light-emitting elements 4, each of which includes a common first electrode 41, simply by applying a voltage to the first electrode 41. Therefore, the display device 12 can reduce the number of drive circuits required to extract light from each subpixel SP, thereby simplifying the structure or manufacturing process. Furthermore, by providing multiple openings OP in each subpixel SP, the display device 12 increases the ratio of the area from which light from each light-emitting element 4 can be obtained to the area of ​​each light-emitting element 4 in a planar view. This allows the display device 12 to reduce the current density applied to the light-emitting element 4 to achieve a predetermined luminance in each subpixel SP, thereby extending the life of the light-emitting element 4.

[0082] In the present embodiment, the outer edges 33 of the multiple openings OP that the display device 12 has in one subpixel SP may all be circular. This allows the display device 12 to place a truncated cone-shaped light-transmitting material 5 inside each opening OP, and for the reasons described above, allows the current density applied to each light-emitting element 4 to be reduced while improving the light extraction efficiency from each light-emitting element 4.

[0083] [Embodiment 4] <Another Example of Opening> A display device according to another embodiment will be described with reference to Fig. 16. Fig. 16 is an enlarged plan view of a display device 13 according to this embodiment, showing an enlarged view of the same position as that shown in Fig. 3.

[0084] The display device 13 according to this embodiment differs from the display devices according to the above-described embodiments in that the shape of the opening OP in plan view is different. For example, as shown in Fig. 16, the opening OP according to this embodiment has an outer edge 35 instead of the outer edge 33. The shape of the outer edge 35 in plan view is a rounded rectangle.

[0085] The display device 13 according to this embodiment is different from the display devices according to the above-described embodiments in terms of the shape of the light-emitting element 4 in a planar view. For example, the light-emitting element 4 according to this embodiment includes a first electrode 44. In this case, each layer of the light-emitting element 4 according to this embodiment may have a substantially rectangular shape along the longitudinal direction of the first electrode 44 in a planar view. Therefore, the light-emitting region of the light-emitting element 4 according to this embodiment is expanded to match the shape of the outer edge 35, compared to the light-emitting region of the light-emitting element 4 according to the above-described embodiments.

[0086] Furthermore, the display device 13 according to this embodiment is different from the display devices according to the above-described embodiments in the shape of the light-transmitting material 5 in a plan view. For example, the light-transmitting material 5 according to this embodiment may have a bottom surface 51 and a top surface 52 each having a rounded rectangular shape, and may have a truncated cone shape with a tip on the bottom surface 51 side.

[0087] Except for the above, the display device 13 according to this embodiment has the same configuration as the display devices according to the above-described embodiments.

[0088] <Specific Example of Shape of Opening> The relationship between the shape of the opening OP and the thickness of the light-transmitting material 5 will be considered below. Fig. 17 is a schematic diagram showing an example of the shape of the outer edge of the opening OP in each embodiment of the present disclosure. In particular, Fig. 17 shows the shape of the outer edge of the opening OP in a plan view.

[0089] As shown in FIG. 17 , the outer edge of the opening OP may be an outer edge 33 that is circular in plan view, or an outer edge 35 that is rectangular in plan view. Alternatively, as shown in FIG. 17 , the outer edge of the opening OP may be an outer edge 36 that is elliptical in plan view, or an outer edge 37 that is rectangular in plan view. In the display devices according to each embodiment, the shape of the outer edge of the opening OP in plan view can be appropriately selected depending on the design of the light-emitting element 4, the light-transmitting material 5, etc. Note that the shape of the outer edge of the opening OP in plan view does not have to be, for example, a perfect circle, an ellipse, a rectangle, or a rounded rectangle. For example, the shape of the outer edge of the opening OP in plan view may deviate from a circular shape due to, for example, manufacturing errors.

[0090] The dimensions of the opening OP in the present disclosure may be, for example, the dimensions of the outer edge of the opening OP in a planar view. For example, the dimension L4 of the outer edge 33 of the opening OP may be the diameter of the outer edge 33 in a planar view. The dimension L5 of the outer edge 35 of the opening OP may be the length in the short direction of the outer edge 35 in a planar view. The dimension L6 of the outer edge 36 of the opening OP may be the minor axis of the outer edge 36 in a planar view. The dimension L7 of the outer edge 37 of the opening OP may be the length in the short direction of the outer edge 37 in a planar view.

[0091] <Relationship Between Thickness of Light-Transmitting Material and Light Extraction Efficiency> Display devices according to Examples 5 to 8 were fabricated and the optical characteristics of each display device were evaluated.

[0092] The display devices according to the respective examples have the same configuration as the display device according to Example 1, except for the dimensions of the outer edge 33 of the opening OP. In Examples 5, 6, 7, and 8, the dimensions of the outer edge 33 are 5 μm, 10 μm, 20 μm, and 30 μm, respectively.

[0093] In the display devices according to Examples 5 and 6, the distance L3, in other words the thickness of the light-transmitting material 5 in the light extraction direction of the light-emitting element 4, was changed, and the light extraction efficiency from the light-emitting element 4 of each display device was measured. Figure 18 is a graph showing the relationship between the distance L3 and the light extraction efficiency from the light-emitting element 4 in the display devices according to each Example. In the graph of Figure 18, the horizontal axis represents the distance L3 (unit: μm), and the vertical axis represents the light extraction efficiency (arbitrary units) from the light-emitting element 4. In the graph of Figure 18, an interpolated line is shown for the data of each Example.

[0094] 18 shows that the distance L3 that maximizes the light extraction efficiency from the light-emitting element 4 of the display device according to each example varies depending on the dimension of the outer edge 33. Based on this, the relationship between the dimension of the outer edge 33 and the distance L3 in order to further increase the light extraction efficiency from the light-emitting element 4 of the display device according to each example will be considered below.

[0095] Fig. 19 is a graph showing the relationship between distance L3 and the dimension of outer edge 33 in each of the display devices according to Examples 5 to 8. In the graph of Fig. 19, the solid line represents the dimension of outer edge 33 and distance L3 at which the light extraction efficiency from light-emitting element 4 of the display device according to each Example is maximized. Also, in the graph of Fig. 19, the dashed line represents the dimension of outer edge 33 and distance L3 at which the light extraction efficiency from light-emitting element 4 of the display device according to each Example is 95% of the maximum value.

[0096] 19 , in each example, the distance L3 at which the light extraction efficiency from the light-emitting element 4 of the display device is maximized is proportional to the dimension of the outer edge 33. Furthermore, by setting the ratio of the distance L3 to the dimension of the outer edge 33 within a predetermined range, the light extraction efficiency from the light-emitting element 4 of the display device can be made close to the maximum value. From the above measurement results, in the display devices according to each of Examples 5 to 8, by setting the distance L3 to be 0.16 to 0.33 times the dimension of the outer edge 33, the light extraction efficiency from the light-emitting element 4 can be made 95% or more of the maximum value.

[0097] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

[0098] REFERENCE SIGNS LIST 1 display device 2 first substrate 3 insulating material 4 light emitting element 5 light-transmitting material 6 second substrate OP opening GA gap 32 tapered surface (inner surface of opening) 33 outer edge 41 first electrode 42 light emitting layer 43 second electrode 53 outer surface (of light-transmitting material) 72 light scattering layer A1 first angle A2 second angle

Claims

1. A display device comprising: a first substrate; an insulating material located on said first substrate and having an opening; a light-emitting element located inside said opening; and a light-transmitting material located on the light extraction side of the light-emitting element and with a portion of the material located inside said opening, wherein there is a gap between the inner surface of the opening and the light-transmitting material.

2. A display device as described in claim 1, wherein a first angle formed between a first surface, which is the surface of the first substrate facing the light-emitting element, and the outer side of the translucent material on the outer side of the translucent material is an acute angle and is larger than a second angle formed between the first surface and the inner side of the opening on the inner side of the insulating material.

3. The display device according to claim 2, wherein the first angle is greater than or equal to 30° and less than or equal to 40°.

4. A display device according to claim 1 or 2, further comprising a second substrate opposed to the first substrate, having light-transmitting properties and a refractive index lower than that of the light-transmitting material, the light-transmitting material being positioned on the second substrate.

5. The display device according to claim 4, wherein the second substrate includes a light scattering layer for scattering light from the light emitting element.

6. A display device according to claim 5, wherein a first angle formed between the surface of the first substrate facing the light-emitting element and the outer surface of the translucent material on the outer side of the translucent material is equal to or greater than 20° and equal to or less than 40°.

7. A display device as described in any one of claims 1 to 6, wherein the light-emitting element includes a first electrode located on the first substrate, a second electrode opposite the first electrode, and a light-emitting layer located between the first electrode and the second electrode, and extracts light from the light-emitting layer to the side of the second electrode, the insulating material covers an end of the first electrode, and a part of the surface of the first electrode is exposed from the opening.

8. The display device according to claim 7, wherein the light-emitting layer is located inside the opening.

9. A display device as described in claim 7 or 8, comprising a plurality of the light-emitting elements and a plurality of the light-transmitting materials, the insulating material having a plurality of the openings, each of the light-emitting elements being located inside each of the openings, each of the light-transmitting materials being located on the light extraction side of each of the light-emitting elements, and the first electrode being common to at least two of the light-emitting elements adjacent to each other.

10. A display device as described in any one of claims 1 to 9, wherein the length from the surface of the first substrate on the side of the light-emitting element to the top surface of the translucent material is greater than the length from the surface of the first substrate on the side of the light-emitting element to the top surface of the insulating material.

11. The display device according to any one of claims 1 to 10, wherein the absolute refractive index of the light-transmitting material is 1.6 or more and 2.0 or less.

12. A display device according to any one of claims 1 to 11, wherein a vacuum is present between the inner surface of the opening and the translucent material, or a gas or a low refractive index material is present between the inner surface of the opening and the translucent material.

13. A display device according to any one of claims 1 to 12, wherein, in a plan view, the outer edge of the opening on the side of the first substrate is circular, elliptical, rounded square, or rectangular.

14. The display device according to claim 13, wherein the length of the light-transmitting material in the light extraction direction of the light-emitting element is 0.16 to 0.33 times the diameter, short diameter, or length in the short side direction of the outer edge in a plan view.

15. The display device according to any one of claims 1 to 14, wherein the light-transmitting material is in the shape of a truncated cone.

16. A method for manufacturing a display device, comprising: preparing a first substrate; preparing a second substrate different from the first substrate and having light-transmitting properties; forming an insulating material on the first substrate; forming an opening in the insulating material; forming a light-emitting element inside the opening; forming a light-transmitting material on the second substrate, the light-transmitting material having a higher refractive index than the second substrate; and arranging the light-transmitting material on the light extraction side of the light-emitting element by bonding the first substrate and the second substrate together, wherein the arrangement of the light-transmitting material includes arranging the light-transmitting material so that a portion of the light-transmitting material is located inside the opening and there is a gap between the inner surface of the opening and the light-transmitting material.

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