Display device and method for manufacturing the same

Abstract

To provide a display device having a light-emitting element with high definition and improved light extraction efficiency.SOLUTION: A display device 1 according to the present disclosure includes a first base 2, a second base 3, a light-emitting element 4, a first transparent body 5, and a second transparent body 6. The second base is stacked on the first base and has a through hole 31 penetrating in the stacking direction. The light-emitting element has an upper surface and a side surface, and is mounted on a portion exposed in a through hole in the first base. The first transparent body is provided in the through hole and seals at least the side surface of the light-emitting element. The second base is located on the first transparent body within the through hole. The second transparent body has a smaller refractive index than the first transparent body, and is thicker than the first transparent body.SELECTED DRAWING: Figure 2A

Description

[Technical field]

[0001] The present disclosure relates to a display device including self-luminous elements such as light-emitting diode (LED) elements, and a manufacturing method thereof. [Background technology]

[0002] 2. Description of the Related Art A display device as described in Patent Document 1, for example, is known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 6-54081 Summary of the Invention

[0004] The display device of the present disclosure includes a first substrate, a second substrate overlaid on the first substrate and having a through hole extending therethrough in the overlapping direction; a light emitting element having an upper surface, a side surface, and a lower surface, the light emitting element being mounted on a portion of the first base exposed in the through hole; a first transparent body provided in the through hole and sealing at least the side surface of the light emitting element; The transparent body has a refractive index smaller than that of the first transparent body, and is thicker than that of the first transparent body.

[0005] The manufacturing method of the display device of the present disclosure includes a first preparation step of preparing a first base having a mounting surface including a portion on which a light emitting element is mounted; a second preparation step of preparing a second substrate having a through hole; a mounting step of mounting a light emitting element having an upper surface, a side surface, and a lower surface on the portion of the first base; a coating step of coating a first transparent resin on the mounting surface and at least on the side surfaces of the light emitting element; a positioning step of stacking the second base on the first base on the mounting surface side so that the light emitting element is located in the through hole; a first forming step of forming a first transparent body that fixes the first base body and the second base body by curing the first transparent resin, and is located between the first base body and the second base body and in the through hole, and seals the light emitting element; a filling step of filling the through holes with a second transparent resin having a refractive index smaller than that of the first transparent resin; and a second forming step of forming a second transparent body having a thickness greater than that of the first transparent body by hardening the second transparent resin. [Brief description of the drawings]

[0006] The objects, features and advantages of the present disclosure will become more apparent from the following detailed description and drawings. [Figure 1] FIG. 1 is a plan view illustrating a display device according to an embodiment of the present disclosure. [Figure 2A] 2 is a cross-sectional view taken along the cutting line A1-A2 in FIG. 1. [Figure 2B] 2B is a cross-sectional view showing a display device according to another embodiment of the present disclosure, the cross-sectional view corresponding to FIG. 2A. [Diagram 3] 1. FIG. 3 is a cross-sectional view showing a schematic diagram of a modified example of the display device in FIG. [Figure 4] 1. FIG. 3 is a cross-sectional view showing a schematic diagram of a modified example of the display device in FIG. [Diagram 5] 1. FIG. 3 is a cross-sectional view showing a schematic diagram of a modified example of the display device in FIG. [Figure 6] 1. FIG. 3 is a cross-sectional view showing a schematic diagram of a modified example of the display device in FIG. [Figure 7] 1. FIG. 3 is a cross-sectional view showing a schematic diagram of a modified example of the display device in FIG. [Figure 8] FIG. 2B is a cross-sectional view that illustrates a modified example of the display device in FIG. 2A. [Figure 9A] FIG. 9 is a cross-sectional view illustrating a modified example of the display device in FIG. [Figure 9B] FIG. 9 is a cross-sectional view illustrating a modified example of the display device in FIG. [Figure 10A] FIG. 9 is a cross-sectional view illustrating a modified example of the display device in FIG. [Figure 10B] FIG. 9 is a cross-sectional view illustrating a modified example of the display device in FIG. [Figure 10C] FIG. 9 is a cross-sectional view illustrating a modified example of the display device in FIG. [Figure 10D] FIG. 9 is a cross-sectional view illustrating a modified example of the display device in FIG. [Figure 11A] FIG. 9 is a cross-sectional view illustrating a modified example of the display device in FIG. [Figure 11B] FIG. 9 is a cross-sectional view illustrating a modified example of the display device in FIG. [Figure 11C] FIG. 9 is a cross-sectional view illustrating a modified example of the display device in FIG. [Figure 11D] FIG. 9 is a cross-sectional view illustrating a modified example of the display device in FIG. [Figure 12] 1 is a flowchart illustrating a method for manufacturing a display device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] The configuration on which the display device of the present disclosure is based will be described. Conventionally, various display devices equipped with a plurality of self-luminous elements such as light-emitting diode elements have been proposed. Patent Document 1 discloses a display device in which a second substrate having a plurality of through holes formed therein corresponding to the plurality of light-emitting diode elements is disposed on a first substrate on which a plurality of light-emitting diode elements are arranged, and each of the plurality of light-emitting diode elements is sealed with a light-transmitting resin.

[0008] In recent years, there has been a demand for higher definition and improved light extraction efficiency in the technical field of display devices. In order to achieve higher definition and improved light extraction efficiency, conventional display devices have room for improvement in fixing the first substrate and the second substrate and sealing the light emitting elements.

[0009] Hereinafter, a display device according to an embodiment of the present disclosure will be described with reference to the accompanying drawings. Each of the drawings referred to below shows main components of the display device according to the embodiment. The display device according to the embodiment may include well-known components such as a circuit board, wiring conductors, control IC, and LSI, which are not shown.

[0010] Fig. 1 is a plan view that illustrates a display device according to an embodiment of the present disclosure, Figs. 2A and 2B are cross-sectional views taken along the cutting line A1-A2 in Fig. 1, and Figs. 3 to 6 are cross-sectional views that illustrate modified examples of the display device in Fig. 1. The cross-sectional views illustrated in Figs. 3 to 6 correspond to the cross-sectional view illustrated in Fig. 2A.

[0011] The display device 1 of the present disclosure comprises a first substrate 2 as a first base, a second substrate 3 as a second base stacked on the first substrate 2 and having a through hole 31 penetrating in the stacking direction, a light-emitting element 4 having an upper surface, a side surface and a lower surface mounted on a portion 2aa exposed in the through hole 31 in the first substrate 2, a first transparent body 5 provided in the through hole 31 and sealing at least the side surface of the light-emitting element 4, and a second transparent body 6 located on the first transparent body 5 within the through hole 31, having a smaller refractive index than the first transparent body 5 and being thicker than the first transparent body 5.

[0012] The above-mentioned configuration provides the following effects. The second transparent body 6 is located on the first transparent body 5 in the through hole 31 of the second base 3, has a smaller refractive index than the first transparent body 5, and is thicker than the first transparent body 5. The second transparent body 6 effectively functions as a light guide, so that the light emitted from the light emitting element 4 can be efficiently extracted to the outside. In addition, the light emitted from the light emitting element 4 is prevented from being totally reflected at the interface between the first transparent body 5 and the second transparent body 6, and is easily reflected at the inner circumferential surface 31a of the through hole 31. This makes it easy to efficiently extract the light emitted from the light emitting element 4 to the outside, and improves the directivity of the light emitted from the through hole 31 to the outside. In addition, the light emitting element 4 is hermetically sealed by the first transparent body 5 and the second transparent body 6, and the heat generated by the light emitting element 4 is efficiently transferred and dissipated to the second base 3 by the first transparent body 5 and the second transparent body 6, improving reliability.

[0013] The first base 2 and the second base 3 may be in the form of a plate-like body such as a substrate, a block-like body, a flexible sheet-like body, a three-dimensional structure having a non-flat surface such as a curved surface or unevenness, etc. In the following description, an example will be described in which the first base 2 is the first substrate 2 and the second base 3 is the second substrate 3. The through hole 31 also functions as a cavity (recess) that reflects the emitted light of the light-emitting element 4 at its inner circumferential surface 31a.

[0014] The light emitting element 4 has a shape having an upper surface, a side surface, and a lower surface, and may be in the shape of, for example, a cube, a rectangular parallelepiped, a cylinder, an elliptical cylinder, a triangular prism, a polygonal prism, a pyramid, or the like.

[0015] The first transparent body 5 seals at least the side surface of the light-emitting element 4. The upper surface of the light-emitting element 4 may be covered by the first transparent body 5 as shown in Fig. 2A, or may be exposed from the first transparent body 5 as shown in Fig. 2B. When the upper surface of the light-emitting element 4 is exposed from the first transparent body 5, for example, when the wavelength conversion member 7 is located between the first transparent body 5 and the second transparent body 6, the radiated light emitted from the upper surface of the light-emitting element 4 directly enters the wavelength conversion member 7 and is efficiently wavelength-converted.

[0016] In the case where the light-emitting element 4 is a horizontally connected type light-emitting element having a flip-chip connection on the underside, and there is a gap between the underside of the light-emitting element 4 and the first surface 2a of the first substrate 2, the underside of the light-emitting element 4 may be covered and sealed with the first transparent body 5. In the case where the light-emitting element 4 is a vertically connected type light-emitting element having a terminal of one polarity on the underside connected to an electrode of one polarity on the first surface 2a of the first substrate 2, and there is no gap between the underside of the light-emitting element 4 and the first surface 2a of the first substrate 2, the underside of the light-emitting element 4 will not be sealed with the first transparent body 5.

[0017] The display device 1 according to this embodiment includes a first substrate 2, a second substrate 3, a light emitting element 4, a first transparent body 5, and a second transparent body 6.

[0018] The first substrate 2 has a first surface (one main surface) 2a. The first surface 2a is also a mounting surface on which the light emitting element 4 is mounted. The first substrate 2 may have a shape in a plan view (i.e., when viewed from a direction perpendicular to the first surface 2a), such as a triangle, a square, a rectangle, a hexagon, a trapezoid, a circle, an ellipse, or another shape.

[0019] The first substrate 2 is made of, for example, a glass material, a ceramic material, a resin material, a metal material, a semiconductor material, or the like.

[0020] Examples of glass materials used for the first substrate 2 include borosilicate glass, crystallized glass, quartz, and soda glass. Examples of ceramic materials used for the first substrate 2 include alumina (Al2O3), aluminum nitride (AlN), silicon nitride (Si3N4), zirconia (ZrO2), and silicon carbide (SiC). Examples of resin materials used for the first substrate 2 include epoxy resin, polyimide resin, and polyamide resin. Examples of metal materials used for the first substrate 2 include aluminum (Al), titanium (Ti), beryllium (Be), magnesium (Mg) (particularly high-purity magnesium with a purity of 99.95% or more), zinc (Zn), tin (Sn), copper (Cu), iron (Fe), chromium (Cr), nickel (Ni), and silver (Ag). The metal material used for the first substrate 2 may be an alloy material. Examples of alloy materials used for the first substrate 2 include iron alloys mainly composed of iron (Fe-Ni alloy, Fe-Ni-Co (cobalt) alloy, Fe-Cr alloy, Fe-Cr-Ni alloy), aluminum alloys mainly composed of aluminum such as duralumin (Al-Cu alloy, Al-Cu-Mg alloy, Mg-Zn-Mg-Cu alloy), magnesium alloys mainly composed of magnesium (Mg-Al alloy, Mg-Zn alloy, Mg-Al-Zn alloy), titanium boronide, Cu-Zn alloy, etc. Examples of semiconductor materials used for the first substrate 2 include silicon (Si), germanium (Ge), gallium arsenide (GaAs), etc.

[0021] The first substrate 2 may have a single layer structure made of the above-mentioned glass material, ceramic material, resin material, metal material, semiconductor material, etc., or may have a multi-layer laminate structure. When the first substrate 2 has a multi-layer laminate structure, the multi-layer may be made of the same material or different materials.

[0022] The second substrate 3 is disposed on the first surface 2a of the first substrate 2, as shown in FIG. 2A, for example. The second substrate 3 has a plate-like or block-like shape. The second substrate 3 has a second surface 3a facing the first surface 2a of the first substrate 2, and a third surface 3b opposite to the second surface 3a. The third surface 3b of the second substrate 3 is a display surface from which the display device 1 emits image light. The shape of the second substrate 3 when viewed in a plane may be, for example, a triangle, a square, a rectangle, a hexagon, a trapezoid, a circle, an ellipse, or the like, or may be another shape. The first substrate 2 and the second substrate 3 may have the same shape when viewed in a plane.

[0023] The second substrate 3 is formed with a through hole 31 penetrating from the second surface 3a to the third surface 3b. The through hole 31 exposes a portion (also referred to as a mounting portion) 2aa of the first surface 2a. The through hole 31 may have a cross-sectional shape parallel to the third surface 3b of the second substrate 3, for example, a square shape, a rectangular shape, a circular shape, an elliptical shape, or other shapes. The through hole 31 may have a cross-sectional shape parallel to the third surface 3b that gradually decreases in a direction from the third surface 3b to the second surface 3a. The through hole 31 has an opening 31b that opens on the third surface 3b. The display device 1 may have a shape in which the periphery of the opening 31b surrounds the periphery of the mounting portion 2aa in a plan view. That is, the through hole 31 may be configured such that the size of the upper opening 31b is larger than the size of the lower opening. In this case, the emitted light of the light emitting element 4 can be efficiently extracted to the outside.

[0024] The second substrate 3 is made of a glass material, a ceramic material, a resin material, a metal material, a semiconductor material, or the like.

[0025] Examples of glass materials used for the second substrate 3 include borosilicate glass, crystallized glass, quartz, and soda glass. Examples of ceramic materials used for the second substrate 3 include alumina, aluminum nitride, silicon nitride, zirconia, and silicon carbide. Examples of resin materials used for the second substrate 3 include epoxy resin, polyimide resin, and polyamide resin. Examples of metal materials used for the second substrate 3 include aluminum, titanium, beryllium, magnesium (particularly high-purity magnesium with a purity of 99.95% or more), zinc, tin, copper, iron, chromium, nickel, and silver. The metal material used for the second substrate 3 may be an alloy material. Examples of alloy materials used for the second substrate 3 include iron alloys mainly composed of iron (Fe-Ni alloy, Fe-Ni-Co alloy, Fe-Cr alloy, Fe-Cr-Ni alloy), aluminum alloys mainly composed of aluminum such as duralumin (Al-Cu alloy, Al-Cu-Mg alloy, Al-Zn-Mg-Cu alloy), magnesium alloys mainly composed of magnesium (Mg-Al alloy, Mg-Zn alloy, Mg-Al-Zn alloy), titanium boronide, Cu-Zn alloy, etc. Examples of semiconductor materials used for the second substrate 3 include silicon, germanium, gallium arsenide, etc.

[0026] The second substrate 3 may have a single-layer structure made of the above-mentioned metal material, or may have a multi-layer laminate structure. When the second substrate 3 has a multi-layer laminate structure, the multi-layer may be made of the same material or different materials. The through-hole 31 may be formed by, for example, a punching method, an electric casting method (plating method), a cutting method, a laser processing method, or the like. When the second substrate 3 is made of a metal material, the through-hole 31 can be formed by, for example, a punching method, an electric casting method, or the like. When the second substrate 3 is made of a semiconductor material, the through-hole 31 can be formed by, for example, a photolithography method including a dry etching process.

[0027] When the second substrate 3 is made of a metal material or a semiconductor material, an insulator or insulating layer made of an electrically insulating material may be disposed between the first surface 2a of the first substrate 2 and the second surface 3a of the second substrate 3. This makes it possible to prevent electrodes, wiring conductors, and the like provided on the first surface 2a from shorting out with each other through the second substrate 3. Examples of electrically insulating materials used for the insulator or insulating layer include silicon oxide and silicon nitride.

[0028] The light-emitting element 4 is mounted on the mounting portion 2aa exposed in the through-hole 31 in the first substrate 2. The light-emitting element 4 is a self-luminous light-emitting element. The self-luminous light-emitting element may be, for example, a light-emitting diode (LED) element, an organic light-emitting diode (OLED) element, a semiconductor laser (LD) element, or the like. The display device 1 of this embodiment includes the light-emitting element 4 which is a light-emitting diode element. The light-emitting diode element is a two-terminal element having an anode terminal 41 and a cathode terminal 42. The light-emitting element 4 may be a micro light-emitting diode element. The micro light-emitting diode element may have a rectangular planar shape with a side length of about 1 μm to about 100 μm or about 5 μm to about 20 μm when mounted on the mounting portion 2aa.

[0029] The display device 1 has an anode electrode 12 and a cathode electrode 13. The anode electrode 12 and the cathode electrode 13 are provided on a first surface 2a of a first substrate 2, as shown in, for example, FIGS. 1 and 2. The anode electrode 12 and the cathode electrode 13 may be located on a mounting portion 2aa of the first surface 2a. The anode terminal 41 and the cathode terminal 42 of the light-emitting element 4 are electrically connected to the anode electrode 12 and the cathode electrode 13, respectively.

[0030] The light emitting element 4 may be flip-chip connected to the anode electrode 12 and the cathode electrode 13. The light emitting element 4 and the anode electrode 12 and the cathode electrode 13 may be electrically and mechanically connected by flip-chip connection using a conductive connection member such as a solder ball, a metal bump, a conductive adhesive, or an anisotropic conductive film (ACF). The connection between the light emitting element 4 and the anode electrode 12 and the cathode electrode 13 is not limited to flip-chip connection. The light emitting element 4 and the anode electrode 12 and the cathode electrode 13 may be electrically connected using a conductive connection member such as a bonding wire.

[0031] When the first substrate 2 is made of a metal material or a semiconductor material, an insulating layer made of silicon oxide, silicon nitride, or the like may be disposed on at least the first surface 2a of the first substrate 2, and the anode electrode 12 and the cathode electrode 13 may be disposed on the insulating layer. This makes it possible to prevent an electrical short circuit between the anode terminal 41 and the cathode terminal 42 of the light-emitting element 4 when the light-emitting element 4 is electrically connected to the anode electrode 12 and the cathode electrode 13.

[0032] The anode electrode 12 and the cathode electrode 13 are connected to a drive circuit. The drive circuit can control the emission, non-emission, emission intensity, etc. of the light-emitting element 4. The drive circuit may be disposed, for example, on one main surface 2a of the first substrate 2, or on the other main surface 2b of the first substrate 2. The drive circuit may be disposed between a plurality of insulating layers made of silicon oxide, silicon nitride, etc., disposed on the one main surface 2a or the other main surface 2b.

[0033] The driving circuit includes a thin film transistor (TFT) and a wiring conductor. The TFT may have a semiconductor film (also called a channel) made of, for example, amorphous silicon (a-Si), low-temperature polysilicon (LTPS), or the like. The TFT may have three terminals: a gate electrode, a source electrode, and a drain electrode. The TFT functions as a switching element that switches between conduction and non-conduction between the source electrode and the drain electrode depending on a voltage applied to the gate electrode. The driving circuit may be formed using a thin film formation method such as a chemical vapor deposition (CVD) method.

[0034] The first transparent body 5 is located between the first surface 2a of the first substrate 2 and the second surface 3a of the second substrate 3. The first transparent body 5 is located within the through hole 31, and for example, as shown in Fig. 2A, is located from above the mounting portion 2aa of the first surface 2a to within the through hole 31. The first transparent body 5 fixes the first substrate 2 and the second substrate 3 to each other, and seals the light-emitting element 4.

[0035] The first transparent body 5 may be made of a transparent resin adhesive. In this case, the first transparent body 5 has an improved effect of fixing the first substrate 2 and the second substrate 3. The first transparent body 5 made of a transparent resin adhesive may be a transparent resin having adhesive properties such as epoxy resin, which is often used as a resin adhesive, or acrylic resin, polycarbonate resin, silicone resin, or the like.

[0036] The first transparent body 5 does not have to have a constant thickness, for example, as shown in Fig. 2A. For example, the second substrate 3 may be provided on the first substrate 2 with a gap therebetween, and the first transparent body 5 may extend between the first substrate 2 and the second substrate 3. In this case, the first transparent body 5, which also functions as a fixing member for fixing the first substrate 2 and the second substrate 3, extends between the first substrate 2 and the second substrate 3, and therefore the effect of fixing the first substrate 2 and the second substrate 3 is further improved.

[0037] The first transparent body 5 may be configured such that the thickness of the extension portion extending between the first substrate 2 and the second substrate 3 is thinner than the thickness of the portion inside the through hole 31. In this case, it is possible to prevent the light emitted from the light emitting element 4 from entering the adjacent through hole 31 through the extension portion. The first transparent body 5 may have a thickness of, for example, about 2 μm or more and about 15 μm or less from the portion located on the mounting portion 2aa to the inside of the through hole 31. Also, the first transparent body 5 may have a thickness of, for example, about 2 μm or more and about 5 μm or less from the portion extending between the first surface 2a and the second surface 3a. In this specification, the "thickness" may mean the thickness in a direction perpendicular to the first surface 2a of the first substrate 2.

[0038] The second substrate 3 may be provided on the first substrate 2 with no space therebetween, and the first transparent body 5 may be located only in the through-hole 31. In this case, it is possible to prevent the emitted light from the light-emitting element 4 from entering the adjacent through-hole 31.

[0039] The first transparent body 5 is made of, for example, a transparent resin (first transparent resin). The first transparent resin may be, for example, an ultraviolet curable resin, a thermosetting resin, a two-part mixed curable resin, or the like. Examples of the first transparent resin include silicone resin and epoxy resin. The first transparent body 5 may have a refractive index of, for example, about 1.4 or more and about 1.9 or less.

[0040] The first transparent body 5 may have a main body made of a first transparent resin and a plurality of light scattering particles dispersed in the main body. The light scattering particles may have a refractive index greater than that of the main body. The light scattering particles may be made of, for example, titanium oxide (TiO2), zirconia (ZrO2), or the like. The light scattering particles can scatter light coming from the outside. The light scattering particles can prevent the light coming from the outside from being incident on the first transparent body 5 and interfering with the light emitted from the light emitting element 4. As a result, the display quality of the display device 1 can be prevented from deteriorating.

[0041] The second transparent body 6 is located in the through hole 31 formed in the second substrate 3. The second transparent body 6 is located closer to the third surface 3b than the first transparent body 5. The second transparent body 6 may be in contact with the first transparent body 5. Alternatively, the first transparent body 5 and the second transparent body 6 may be separated from each other by providing another optical member between the first transparent body 5 and the second transparent body 6. The second transparent body 6 is thicker than the first transparent body 5. The second transparent body 6 may be thicker than the portion of the first transparent body 5 located from above the mounting portion 2aa to inside the through hole 31, as shown in FIG. 2A, for example. The second transparent body 6 may have a thickness exceeding half the thickness of the second substrate 3, or may have a thickness exceeding two-thirds the thickness of the second substrate 3.

[0042] The second transparent body 6 is made of a transparent resin (second transparent resin). The second transparent resin may be, for example, an ultraviolet curable resin, a thermosetting resin, a two-part mixed curable resin, or the like. Examples of the second transparent resin include silicone resin, epoxy resin, and acrylic resin. The second transparent body 6 has a smaller refractive index than the first transparent body 5. The second transparent body 6 may have a refractive index of, for example, about 1.33 or more and about 1.50 or less.

[0043] The second transparent body 6 may have a main body made of a second transparent resin and a plurality of light scattering particles dispersed in the main body. The light scattering particles may have a refractive index greater than that of the main body of the second transparent body 6. The light scattering particles may be made of, for example, silicon oxide (SiO2). The light scattering particles can scatter light coming from the outside. The light scattering particles can prevent the light coming from the outside from entering the second transparent body 6 and interfering with the light emitted from the light emitting element 4. As a result, the deterioration of the display quality of the display device 1 can be prevented.

[0044] FIG. 2A shows an example in which the upper surface (surface on the second transparent body 6 side) of the first transparent body 5 and the lower surface (surface on the first transparent body 5 side) of the second transparent body 6 are substantially parallel to the third surface 3b, but the upper surface of the first transparent body 5 may be curved concavely toward the first substrate 2. Also, the lower surface of the second transparent body 6 may be curved convexly toward the first substrate 2. According to such a configuration of the first transparent body 5 and the second transparent body 6, the optical function exhibited by the interface between the first transparent body 5 and the second transparent body 6 allows the emitted light of the light-emitting element 4 to be concentrated on a virtual line that passes through the center of the light-emitting element 4 and is perpendicular to the first surface 2a. As a result, it is possible to increase the directivity of the image light emitted from the display device 1.

[0045] In the display device 1 of this embodiment, the first transparent body 5 is located between the first substrate 2 and the second substrate 3 and in the through hole 31. The first transparent body 5 is located on the first surface 2a, is interposed between the first surface 2a and the second surface 3a, and extends into the through hole 31. Therefore, even if the pixel density of the display device 1 is increased, that is, even if the number of through holes 31 formed in the second substrate 3 is increased and the area of ​​the second surface 3a (the surface facing the first substrate 2) of the second substrate 3 is reduced, the first substrate 2 and the second substrate 3 can be firmly fixed. In this way, the display device 1 of this embodiment can be a highly reliable and high-definition display device.

[0046] Furthermore, in the display device 1 of the present embodiment, the refractive index of the second transparent body 6 is smaller than the refraction of the first transparent body 5. This makes it possible to prevent the emitted light of the light-emitting element 4 from being totally reflected at the interface between the first transparent body 5 and the second transparent body 6 and from being prevented from propagating to the outside, thereby improving the light extraction efficiency.

[0047] The second transparent body 6, which is thicker than the first transparent body 5, may have a higher light transmittance than the first transparent body 5. This significantly improves the total light transmittance of the first transparent body 5 and the second transparent body 6, allowing the light emitted from the light emitting element 4 to be efficiently extracted to the outside. The light transmittance of the second transparent body 6 may be more than 1 time and not more than about 2 times the light transmittance of the first transparent body 5, but is not limited to this range.

[0048] When the surface of the first transparent body 5 on the second transparent body 6 side is a concave surface (first concave surface) recessed toward the light emitting element 4 side, and the upper surface of the second transparent body 6 is a concave surface (second concave surface) recessed toward the light emitting element 4 side, the curvature of the second concave surface may be smaller than the curvature of the first concave surface. In this case, it is possible to suppress deterioration in the convergence of the light radiated to the outside from the through hole 31. In addition, since the contact area (bonding area) between the first transparent body 5 and the second transparent body 6 is increased, the bonding strength between the first transparent body 5 and the second transparent body 6 is improved.

[0049] Below, modified examples of the display device according to an embodiment of the present disclosure will be described.

[0050] The display device 1 may include a wavelength conversion member 7 located between the first transparent body 5 and the second transparent body 6, as shown in FIG. 3, for example. The wavelength conversion member 7 converts the light emitted from the light emitting element 4 into light with a wavelength different from the wavelength of the emitted light. When the light emitting element 4 is a blue LED element, the wavelength conversion member 7 may convert the blue light emitted from the light emitting element 4 into red light or green light. When the light emitting element 4 is an ultraviolet LED element, the wavelength conversion member 7 may convert the ultraviolet light emitted from the light emitting element 4 into red light, green light, or blue light.

[0051] The wavelength conversion member 7 may contain a phosphor or quantum dots. The wavelength conversion member 7 may be configured to include a body made of a light-transmitting insulating resin or a light-transmitting glass, and a phosphor or quantum dots dispersed in the body. The phosphor or quantum dots may be uniformly dispersed in the body.

[0052] The insulating resin used in the wavelength conversion member 7 may be, for example, an ultraviolet curing resin, a thermosetting resin, etc. Examples of the insulating resin used in the wavelength conversion member 7 include a fluorine-based resin, a silicone resin, an acrylic resin, an epoxy resin, and a urea resin. Examples of the glass used in the wavelength conversion member 7 include borosilicate glass, crystallized glass, quartz, and soda glass.

[0053] As the phosphor material used for the phosphor of the wavelength conversion member 7, various materials that can be excited by the emitted light of the light emitting element 4 and emit light of a wavelength different from that of the emitted light can be used. Examples of phosphors that emit red fluorescence include La2O2S:Eu and Y2O2S:Eu. Examples of phosphors that emit green fluorescence include ZnS:Cu,Al and SrGa2S4:Eu. Examples of phosphors that emit blue fluorescence include BaMgAl 10 O 12 :Eu, (Sr,Ca,Ba,Mg) 10 (PO4)6C 12 :Eu, etc. Note that "~:Eu" means that Eu is contained as a trace component. Quantum dots are particles having a diameter of about 1 nm or more and about 100 nm or less. Examples of quantum dot materials used for the quantum dots of the wavelength conversion member 7 include CdSe (cadmium selenide), CdS (cadmium sulfide), InP (indium phosphide), etc. When the wavelength conversion member 7 contains quantum dots, the color purity of the light emitted by the wavelength conversion member 7 can be improved.

[0054] The display device 1 may include a color filter 8 located between the second transparent body 6 and the wavelength conversion member 7, as shown in FIG. 4, for example. The color filter 8 is made of a resin to which a pigment or a dye has been added. The pigment used in the color filter 8 may be an organic pigment or an inorganic pigment. The resin used in the color filter 8 may be, for example, an ultraviolet curing resin, a thermosetting resin, or the like. Examples of the resin used in the color filter 8 include an acrylic resin, a polycarbonate resin, and the like.

[0055] When the light emitting element 4 emits blue light and the wavelength conversion member 7 converts the blue light into red light, the color filter 8 is configured to transmit the red light and absorb and suppress the transmission of visible light other than red light. In other words, the color filter 8 is configured to absorb the visible light that has not been converted into red light among the light emitted by the light emitting element 4. The color filter 8 only needs to absorb and suppress the transmission of visible light other than red light to an extent that is not perceptible to the human eye. This can reduce color mixing due to light other than red light, and improve the color reproducibility of the display device 1. In addition, when the light emitting element 4 emits blue light and the wavelength conversion member 7 converts the blue light into green light, the color filter 8 is configured to transmit the green light and absorb and suppress the transmission of visible light other than green light. In other words, the color filter 8 is configured to absorb the visible light that has not been converted into green light among the light emitted by the light emitting element 4. This can reduce color mixing due to light other than green light, and improve the color reproducibility of the display device 1.

[0056] When the light emitting element 4 emits ultraviolet light and the wavelength conversion member 7 converts the ultraviolet light into visible light such as red light, green light, or blue light, the display device 1 may not include the color filter 8. The light emitted from the light emitting element 4 that is not converted into visible light by the wavelength conversion member 7 is essentially ultraviolet light or near-ultraviolet light that is not visible to the human eye. Therefore, even if the display device 1 does not include the color filter 8, the color reproducibility of the display device 1 is not substantially reduced.

[0057] The wavelength conversion member 7 may be included in the first transparent body 5 and / or the second transparent body 6. When the wavelength conversion member 7 is included in the first transparent body 5, the wavelength of the light emitted from the light emitting element 4 can be directly converted, and the wavelength conversion efficiency is likely to be improved. When the wavelength conversion member 7 is included in the second transparent body 6, the wavelength of the light emitted from the light emitting element 4 can be converted via a long optical path, and the wavelength conversion efficiency is likely to be improved.

[0058] The display device 1 may be configured so that the light emitted from the light emitting element 4 is reflected at least once by the inner circumferential surface 31a of the through hole 31. This makes it possible to make the image light emitted from the third surface 3b closer to parallel light, thereby improving the directivity of the image light emitted from the display device 1.

[0059] In order to reflect the emitted light of the light-emitting element 4 at least once on the inner peripheral surface 31a, for example, the thickness of the second substrate 3 may be made thicker than the thickness of the first substrate 2. In other words, the depth of the through hole 31 may be made deeper. The display device 1 may be configured so that the emitted light of the light-emitting element 4 is reflected at least once on the inner peripheral surface 31a of the through hole 31 by appropriately designing the thickness of the second substrate 3, the shape of the through hole 31, the dimensional ratio between the through hole 31 and the light-emitting element 4, and the like, based on, for example, the intensity distribution of the emitted light of the light-emitting element 4.

[0060] The through-hole 31 may have a depth that allows at least a part of the emitted light from the light-emitting element 4 to be reflected multiple times by the inner circumferential surface 31a. In this case, the emitted light from the light-emitting element 4 is more likely to be emitted with high convergence to the outside of the second substrate 3. The depth of the through-hole 31 may be about 3 to 10 times, or about 5 to 10 times, the height of the light-emitting element 4, but is not limited to these ranges.

[0061] The light emitting element 4 may be configured such that the maximum intensity light of the emitted light is inclined with respect to the perpendicular line of the upper surface of the light emitting element 4, and the maximum intensity light is reflected multiple times by the inner peripheral surface 31a of the through hole 31. In this case, the emitted light of the light emitting element 4 is likely to be radiated to the outside of the second substrate 3 efficiently and with high convergence. The number of reflections of the maximum intensity light is from 2 to about 5 times, but is not limited to this range. The radiation direction of the maximum intensity light may be inclined with respect to the perpendicular line of the surface of the mounting portion 2aa of the light emitting element 4. As a result, the directivity of the light radiated to the outside from the through hole 31 is improved. For example, the thickness of the first substrate 2 may be about 0.2 mm to 2.0 mm, and the thickness of the second substrate 3 may be about 1.0 mm to 3.0 mm so that the maximum intensity light is reflected multiple times by the inner peripheral surface 31a of the through hole 31, but is not limited to these thickness values. The direction of the maximum intensity light may form an angle of about 30° to 60° with respect to the perpendicular line to the mounting portion 2aa, but is not limited to this angle range.

[0062] In the second substrate 3, the inner circumferential surface 31a of the through hole 31 may be a mirror surface. This can increase the reflectance of the light emitted from the light-emitting element 4 at the inner circumferential surface 31a, and reduce the loss of the light emitted from the light-emitting element 4 when it is reflected at the inner circumferential surface 31a. As a result, the efficiency of extracting the light emitted from the light-emitting element 4 to the outside of the device can be improved, and an image with high brightness can be displayed.

[0063] The inner circumferential surface 31a of the through hole 31 may be subjected to mirror finishing, for example, by electrolytic polishing, chemical polishing, or the like. The inner circumferential surface 31a of the through hole 31 may have a surface roughness Ra of, for example, about 0.01 μm or more and about 0.1 μm or less. The inner circumferential surface 31a may have a reflectance to visible light of, for example, about 85% or more and about 95% or less.

[0064] 5, the display device 1 may include a light reflecting film 9 provided on the inner circumferential surface 31a of the through hole 31. This can increase the reflectance of light in the through hole 31 and reduce the loss caused when the light emitted from the light emitting element 4 is reflected inside the through hole 31, regardless of the material constituting the second substrate 3, the surface roughness Ra of the inner circumferential surface 31a, etc. As a result, the display device 1 can improve the efficiency of extracting light emitted from the light emitting element 4 to the outside of the device, and can display an image with high brightness.

[0065] The light reflecting film 9 may be made of, for example, a metal material, etc. Examples of the metal material used for the light reflecting film 9 include aluminum, silver, and gold.

[0066] The light reflecting film 9 may be formed on the inner circumferential surface 31a of the through hole 31 by a thin film forming method such as a CVD method, a vapor deposition method, a plating method, or the like, or may be formed by a film forming method such as a thick film forming method in which a resin paste containing particles including aluminum, silver, gold, or the like is baked and solidified. The light reflecting film 9 may be formed on the inner circumferential surface 31a of the through hole 31 by a bonding method in which a film containing aluminum, silver, gold, or the like or a film of the above alloy is bonded. A protective film may be provided on the outer surface of the light reflecting film 9 to suppress a decrease in reflectance due to oxidation of the light reflecting film 9.

[0067] The third surface 3b of the second substrate 3 may be roughened by blasting or the like. By roughening the third surface 3b, the surface area of ​​the third surface 3b can be increased. As a result, heat generated by the light-emitting element 4 can be transferred or conducted to the second substrate 3, and can be effectively dissipated to the outside from the third surface 3b of the second substrate 3.

[0068] Furthermore, by roughening the third surface 3b, light coming from the outside (external light) can be diffusely reflected at the third surface 3b, thereby preventing the reflected external light from interfering with the image light emitted from the display device 1. As a result, deterioration in the display quality of the display device 1 can be prevented.

[0069] The display device 1 may include a light absorbing film 10 provided on the third surface 3b of the second substrate 3, as shown in Fig. 5, for example. The light absorbing film 10 can absorb external light incident on the third surface 3b. As a result, reflection of external light on the third surface 3b can be reduced, and interference of reflected external light with image light emitted from the display device 1 can be suppressed. As a result, deterioration of the display quality of the display device 1 can be suppressed.

[0070] The light absorbing film 10 may be formed, for example, by applying a photocurable or thermosetting resin material containing a light absorbing material to the third surface 3b of the second substrate 3 and curing the resin material. The light absorbing material may be, for example, an inorganic pigment. The inorganic pigment may be, for example, a carbon-based pigment such as carbon black, a nitride-based pigment such as titanium black, or a metal oxide-based pigment such as Cr-Fe-Co, Cu-Co-Mn (manganese), Fe-Co-Mn, or Fe-Co-Ni-Cr.

[0071] The light absorbing film 10 may have an uneven structure on the surface for absorbing incident light. For example, the light absorbing film 10 may be a black film formed by mixing a black pigment such as carbon black into a base material such as silicone resin, and the uneven structure may be formed on the surface of the black film. In this case, the light absorption property is significantly improved. The arithmetic mean roughness of the uneven structure may be about 10 μm to 50 μm, or about 20 μm to 30 μm. The uneven structure may be formed by, for example, a transfer method or the like.

[0072] The display device 1 may be configured to include a plurality of pixels 11. Each pixel 11 may have sub-pixels 11R, 11G, and 11B, for example, as shown in FIG.

[0073] The sub-pixel 11R may be configured to emit red light. The sub-pixel 11R may include a light-emitting element 4 that emits blue light, and a wavelength conversion member 7R that converts the blue light emitted by the light-emitting element 4 into red light. The wavelength conversion member 7R may be provided in the through-hole 31 and located on the surface of the first transparent body 5 on the third surface 3b side, as shown in FIG. 6, for example. The sub-pixel 11R may have a color filter 8R that transmits only red light. The color filter 8R may be located closer to the third surface 3b than the wavelength conversion member 7R.

[0074] The sub-pixel 11G may be configured to emit green light. The sub-pixel 11G may include a light-emitting element 4 that emits blue light, and a wavelength conversion member 7G that converts the blue light emitted by the light-emitting element 4 into green light. The wavelength conversion member 7G may be provided in the through-hole 31 and located on the surface of the first transparent body 5 on the third surface 3b side, as shown in FIG. 6, for example. The sub-pixel 11G may have a color filter 8G that transmits only green light. The color filter 8G may be located closer to the third surface 3b than the wavelength conversion member 7G.

[0075] The sub-pixel 11B may be configured to emit blue light. The sub-pixel 11G may be configured to include a light-emitting element 4 that emits blue light.

[0076] The display device 1 configured as above enables full-color display. Moreover, the display device 1 configured as above can perform full-color display using only blue LED elements. As a result, it is possible to reduce unevenness in the display image caused by different light-emitting characteristics of the different types of light-emitting diode elements, and to reduce the manufacturing cost of the display device 1.

[0077] The display device 1 capable of full-color display may be configured as follows.

[0078] The display device 1 has sub-pixels 11R, 11G, and 11B, as shown in FIG. 7, for example. The sub-pixel 11R includes a light-emitting element 4 that emits ultraviolet light, and a wavelength conversion member 7R that converts the ultraviolet light emitted by the light-emitting element 4 into red light. The wavelength conversion member 7R is provided in the through-hole 31, as shown in FIG. 7, for example, and is located on the surface of the first transparent body 5 on the third surface 3b side. The sub-pixel 11G includes a light-emitting element 4 that emits ultraviolet light, and a wavelength conversion member 7G that converts the ultraviolet light emitted by the light-emitting element 4 into green light. The wavelength conversion member 7G is provided in the through-hole 31, as shown in FIG. 7, for example, and is located on the surface of the first transparent body 5 on the third surface 3b side. The sub-pixel 11B includes a light-emitting element 4 that emits ultraviolet light, and a wavelength conversion member 7B that converts the ultraviolet light emitted by the light-emitting element 4 into blue light. Wavelength conversion member 7B is provided in through-hole 31, for example, as shown in FIG. 7, and is located on the surface of first transparent body 5 on the third surface 3b side.

[0079] The display device 1 configured as above enables full-color display and makes it possible to omit the color filter 8. Moreover, the display device 1 configured as above can perform full-color display using only ultraviolet LED elements. As a result, it is possible to reduce unevenness in the display image caused by different light-emitting characteristics of each type of light-emitting diode element, and to reduce the manufacturing cost of the display device 1.

[0080] Fig. 8 is a cross-sectional view showing a modified example of the display device of Fig. 2A. Figs. 9A, 9B, 10A-10D, and 11A-11D are cross-sectional views showing a modified example of the display device of Fig. 8. Figs. 9A, 9B, 10A-10D, and 11A-11D show an enlarged view of part A of Fig. 8. Figs. 8, 9A, 9B, 10A-10D, and 11A-11D omit anode terminal 41, cathode terminal 42, anode electrode 12, and cathode electrode 13.

[0081] In the display device 1 of FIG. 8, the second substrate 3 is provided on the first substrate 2 with a gap therebetween, and the first transparent body 5 extends between the first substrate 2 and the second substrate 3, with the thickness of the extension 5e being thinner than the thickness of the portion inside the through-hole 31. The light absorbing film 10 is located on the third surface 3b of the second substrate 3. In this case, the first substrate 2 and the second substrate 3 are firmly joined and fixed by the extension 5e of the first transparent body 5. Also, it is possible to prevent the emitted light of the light emitting element 4 from entering the adjacent through-hole 31.

[0082] FIG. 9A shows a configuration in which the second surface 3a of the second substrate 3, which is the surface of the second substrate 3 facing the first substrate 2 in the configuration of FIG. 8, is a rough surface having many fine irregularities. In this case, the bonding area of ​​the extension portion 5e is increased, and the first substrate 2 and the second substrate 3 are more firmly bonded and fixed by the extension portion 5e of the first transparent body 5. In addition, even if the emitted light of the light-emitting element 4 enters the extension portion 5e, it is scattered by the fine irregularities of the second surface 3a, and it is possible to further prevent the light from entering the adjacent through-hole 31. FIG. 9B shows a configuration in which the first surface 2a of the first substrate 2, which is the surface of the first substrate 2 facing the second substrate 3 in the configuration of FIG. 8, is a rough surface having many fine irregularities. In this case, the same effect as the configuration of FIG. 9A is also achieved.

[0083] When the second surface 3a of the second substrate 3 is a rough surface, the arithmetic mean roughness of the second surface 3a may be about 50 nm to 1000 nm, or may be about 100 nm to 1000 nm, but is not limited to these ranges. The same applies when the first surface 2a of the first substrate 2 is a rough surface.

[0084] FIG. 10A shows a configuration in which a recess 3o is disposed at a portion of the lower end of the inner circumferential surface 3h of the through hole 31 formed in the second substrate 3 in the configuration of FIG. 8 that contacts the first transparent body 5. In this case, the bonding area of ​​the first transparent body 5 increases, and the first substrate 2 and the second substrate 3 are more firmly bonded and fixed by the first transparent body 5. There may be a plurality of recesses 3o in the circumferential direction and / or depth direction of the inner circumferential surface 3h, or the recesses 3o may be groove-shaped formed over the entire circumference of the inner circumferential surface 3h in the circumferential direction. In these cases, the bonding area of ​​the first transparent body 5 increases further, and the first substrate 2 and the second substrate 3 are more firmly bonded and fixed by the first transparent body 5.

[0085] 10B shows a configuration in which a step 3d is disposed at a corner of the lower end of the through hole 31 formed in the second substrate 3 in the configuration of FIG. 8. In this case, the bonding area of ​​the first transparent body 5 increases, and the first substrate 2 and the second substrate 3 are more firmly bonded and fixed by the first transparent body 5. The step 3d may be formed over the entire circumference in the circumferential direction of the inner circumferential surface 3h. In this case, the bonding area of ​​the first transparent body 5 increases further, and the first substrate 2 and the second substrate 3 are more firmly bonded and fixed by the first transparent body 5.

[0086] FIG. 10C shows a configuration in which a recess 3o is disposed on the second surface 3a of the second substrate 3 in the configuration of FIG. 8. In this case, the bonding area of ​​the first transparent body 5 is increased, and the first substrate 2 and the second substrate 3 are bonded and fixed more firmly by the first transparent body 5. In addition, even if the emitted light of the light-emitting element 4 enters the extension portion 5e, it is scattered by the recess 3o of the second surface 3a, and it is possible to further suppress the light from entering the adjacent through-hole 31. The recess 3o may be formed in a plurality of portions on the second surface 3a so as to surround the light-emitting element 4 in a plan view, or may be formed in a groove shape. In these cases, the bonding area of ​​the first transparent body 5 is further increased, and the first substrate 2 and the second substrate 3 are bonded and fixed more firmly by the first transparent body 5. In addition, even if the emitted light of the light-emitting element 4 enters the extension portion 5e, it is scattered by the recess 3o of the second surface 3a, and it is possible to further suppress the light from entering the adjacent through-hole 31. Furthermore, the recess 3o may be disposed on an edge portion of the second surface 3a close to the light emitting element 4. In this case, even if the emitted light of the light emitting element 4 enters the extension portion 5e, the light is scattered by the recess 3o located close to the light emitting element 4, and therefore, the light can be further prevented from entering the adjacent through hole 31.

[0087] FIG. 10D shows a configuration in which a recess 2o is arranged on the first surface 2a of the first substrate 2 in the configuration of FIG. 8. In this case, the bonding area of ​​the first transparent body 5 is increased, and the first substrate 2 and the second substrate 3 are bonded and fixed more firmly by the first transparent body 5. In addition, even if the emitted light of the light-emitting element 4 enters the extension portion 5e, it is scattered by the recess 2o of the first surface 2a, and it is possible to further suppress it from entering the adjacent through hole 31. The recess 2o may be formed in a plurality of numbers on the first surface 2a so as to surround the light-emitting element 4 in a plan view, or may be formed in a groove shape. In these cases, the bonding area of ​​the first transparent body 5 is further increased, and the first substrate 2 and the second substrate 3 are bonded and fixed more firmly by the first transparent body 5. In addition, even if the emitted light of the light-emitting element 4 enters the extension portion 5e, it is scattered by the recess 2o of the first surface 2a, and it is possible to further suppress it from entering the adjacent through hole 31. Furthermore, the recess 2o may be disposed at a portion of the first surface 2a close to the light emitting element 4. In this case, even if the emitted light from the light emitting element 4 enters the extension portion 5e, the light is scattered by the recess 2o located close to the light emitting element 4, and therefore, the light can be further prevented from entering the adjacent through hole 31.

[0088] 11A shows a configuration in which, in the configuration of FIG. 8, a convex portion 3t is disposed at a portion in contact with the first transparent body 5 at the lower end of the inner circumferential surface 3h of the through hole 31 formed in the second substrate 3. In this case, the bonding area of ​​the first transparent body 5 increases, and the first substrate 2 and the second substrate 3 are bonded and fixed more firmly by the first transparent body 5. The convex portion 3t may be multiple in the circumferential direction and / or depth direction of the inner circumferential surface 3h, or may be in the form of a bank formed around the entire circumference of the inner circumferential surface 3h in the circumferential direction. In these cases, the bonding area of ​​the first transparent body 5 increases further, and the first substrate 2 and the second substrate 3 are bonded and fixed more firmly by the first transparent body 5.

[0089] 11B shows a configuration in which a convex portion 3t is disposed at a corner of the lower end of the through hole 31 formed in the second substrate 3 in the configuration of FIG. 8. In this case, the bonding area of ​​the first transparent body 5 increases, and the first substrate 2 and the second substrate 3 are more firmly bonded and fixed by the first transparent body 5. The convex portion 3t may be formed in a bank shape over the entire circumference in the circumferential direction of the inner circumferential surface 3h. In this case, the bonding area of ​​the first transparent body 5 increases further, and the first substrate 2 and the second substrate 3 are more firmly bonded and fixed by the first transparent body 5.

[0090] FIG. 11C shows a configuration in which a convex portion 3t is arranged on the second surface 3a of the second substrate 3 in the configuration of FIG. 8. In this case, the bonding area of ​​the first transparent body 5 is increased, and the first substrate 2 and the second substrate 3 are bonded and fixed more firmly by the first transparent body 5. Furthermore, even if the emitted light of the light-emitting element 4 enters the extension portion 5e, it is scattered by the convex portion 3t of the second surface 3a, and it is possible to further prevent the light from entering the adjacent through-hole 31. The convex portion 3t may be formed in a plurality of portions on the second surface 3a so as to surround the light-emitting element 4 in a plan view, or may be formed in a bank shape. In these cases, the bonding area of ​​the first transparent body 5 is further increased, and the first substrate 2 and the second substrate 3 are bonded and fixed more firmly by the first transparent body 5. Furthermore, even if the emitted light of the light-emitting element 4 enters the extension portion 5e, it is scattered by the convex portion 3t of the second surface 3a, and it is possible to further prevent the light from entering the adjacent through-hole 31. Furthermore, the protrusion 3t may be disposed on an edge portion of the second surface 3a close to the light emitting element 4. In this case, even if the emitted light from the light emitting element 4 enters the extension portion 5e, the light is scattered by the protrusion 3t located close to the light emitting element 4, and therefore, the light can be further prevented from entering the adjacent through hole 31.

[0091] FIG. 11D shows a configuration in which a convex portion 2t is arranged on the first surface 2a of the first substrate 2 in the configuration of FIG. 8. In this case, the bonding area of ​​the first transparent body 5 is increased, and the first substrate 2 and the second substrate 3 are bonded and fixed more firmly by the first transparent body 5. In addition, even if the emitted light of the light-emitting element 4 enters the extension portion 5e, it is scattered by the convex portion 2t of the first surface 2a, and it is possible to further suppress the light from entering the adjacent through-hole 31. The convex portion 2t may be formed in a plurality of portions on the first surface 2a so as to surround the light-emitting element 4 in a plan view, or may be formed in a bank shape. In these cases, the bonding area of ​​the first transparent body 5 is further increased, and the first substrate 2 and the second substrate 3 are bonded and fixed more firmly by the first transparent body 5. In addition, even if the emitted light of the light-emitting element 4 enters the extension portion 5e, it is scattered by the convex portion 2t of the first surface 2a, and it is possible to further suppress the light from entering the adjacent through-hole 31. Furthermore, the protrusion 2t may be disposed at a portion of the first surface 2a close to the light-emitting element 4. In this case, even if the light emitted from the light-emitting element 4 enters the extension portion 5e, the light is scattered by the protrusion 2t located close to the light-emitting element 4, and therefore, the light can be further prevented from entering the adjacent through-hole 31.

[0092] The display device 1 of the present disclosure may be a transparent display device in which the first substrate 2 and the second substrate 3 are made of a transparent material such as a flexible transparent resin material. In this case, it can be installed on a wall surface of a building, vehicle, aircraft, ship, etc. that has a non-flat surface such as a curved surface. The display device 1 may also be a flexible double-sided display type transparent display device. In this case, it can be installed on a transparent member such as a window glass of a building, vehicle, aircraft, ship, etc., and can display images on both the front side and the back side. The image on the front side and the image on the back side may be the same or different.

[0093] The manufacturing method of the display device 1 of the present disclosure includes a first preparation step of preparing a first substrate 2 having a mounting surface (first surface) 2a including a portion 2aa on which a light-emitting element 4 is mounted, a second preparation step of preparing a second substrate 3 having a through hole 31, a mounting step of mounting a light-emitting element 4 having an upper surface, a side surface and a lower surface on the portion 2aa of the first substrate 2, a coating step of coating a first transparent resin on the mounting surface 2a and at least the side surface of the light-emitting element 4, and a mounting step of mounting the second substrate 3 on the first substrate 2 on the mounting surface 2a side, with the light-emitting element 4 positioned within the through hole 31. The method includes a positioning step of overlapping the first substrate 2 and the second substrate 3 so as to be aligned in a direction perpendicular to the substrate 2, a first forming step of fixing the first substrate 2 and the second substrate 3 by curing the first transparent resin and forming a first transparent body 5 that is located between the first substrate 2 and the second substrate 3 and in the through hole 31 and seals the light emitting element 4, a filling step of filling the through hole 31 with a second transparent resin having a smaller refractive index than the first transparent resin, and a second forming step of forming the second transparent body 6 that is thicker than the first transparent body 5 by curing the second transparent resin. With this configuration, a high-definition display device 1 with excellent reliability and light extraction efficiency can be manufactured.

[0094] The arrangement step may include a pressing operation for pressing the second substrate 3 relatively against the first substrate 2. In this case, as in the configuration of FIG. 8, by adjusting the pressing force, it is easy to make the thickness of the extension 5e of the first transparent body 5 thinner than the thickness of the portion of the through hole 31 of the first transparent body 5. In addition, by increasing the pressing force, the extension 5e of the first transparent body 5 can be eliminated. In the pressing operation, the second substrate 3 may be made movable relative to the first substrate 2 while the first substrate 2 is placed on a jig such as a mounting table, and the second substrate 3 may be pressed against the first substrate 2 whose position is fixed. In addition, the first substrate 2 may be made movable relative to the second substrate 3 while the second substrate 3 is suspended on a suspension device or the like, and the first substrate 2 may be pressed against the second substrate 3 whose position is fixed. In addition, the first substrate 2 and the second substrate 3 may be made movable and pressed against each other.

[0095] A method for manufacturing a display device according to an embodiment of the present disclosure will be described below. Fig. 12 is a flowchart illustrating a method for manufacturing a display device according to an embodiment of the present disclosure.

[0096] The manufacturing method of the display device of this embodiment includes a first preparation process S1, a second preparation process S2, a mounting process S3, a coating process S4, a placement process S5, a first formation process S6, a filling process S7, and a second formation process S8.

[0097] The first preparation step S1 is a step of preparing the first substrate 2. The first substrate 2 can be produced using the above-mentioned glass material, ceramic material, resin material, metal material, semiconductor material, etc. In this step, an anode electrode 12 and a cathode electrode 13 may be formed in a portion (mounting portion) 2aa on the first surface 2a of the first substrate 2 where the light emitting element 4 is mounted. In addition, in this step, electrodes, wiring conductors, driving circuits, etc. for driving the light emitting element 4 may be formed on at least one of the one main surface 2a and the other main surface 2b of the first substrate 2.

[0098] The second preparation step S2 is a step of preparing the second substrate 3. The second substrate 3 can be made using the above-mentioned glass material, ceramic material, resin material, metal material, semiconductor material, etc. The through hole 31 penetrating the second substrate 3 from the second surface 3a to the third surface 3b can be formed by a punching method, an electric casting method (plating method), a cutting method, a laser processing method, a photolithography method including a dry etching step, etc. In this step, the inner peripheral surface 31a of the through hole 31 may be mirror-finished, or a light-reflecting film may be formed on the inner peripheral surface 31a. In addition, in this step, the third surface 3b of the second substrate 3 may be roughened, or a light-absorbing film may be formed on the third surface 3b.

[0099] The order of performing the first preparation step S1 and the second preparation step S2 is not limited to the order shown in Fig. 12. The first preparation step S1 may be performed after the second preparation step S2, or the first preparation step S1 and the second preparation step S2 may be performed simultaneously.

[0100] The mounting step S3 is a step of mounting the light emitting element 4 on the portion 2aa of the first substrate 2. In this step, the light emitting element 4 may be flip-chip connected to the anode electrode 12 and the cathode electrode 13 formed in the mounting portion 2aa.

[0101] The application step S4 is a step of applying a first transparent resin onto the first surface 2a of the first substrate 2 and onto the light-emitting element 4 mounted in the mounting portion 2aa. The first transparent resin can be applied using a coating method such as a dispenser or a slit coater.

[0102] The arrangement step S5 is a step of relatively positioning the first substrate 2 and the second substrate 3. In this step, the first substrate 2 and the second substrate 3 are relatively positioned such that the first surface 2a of the first substrate 2 faces the second surface 3a of the second substrate 3 and the light emitting element 4 is positioned within the through hole 31. It is sufficient that at least a portion of the light emitting element 4 is positioned within the through hole 31.

[0103] The first formation step S6 is a step of forming a first transparent body 5 by curing the first transparent resin. The first transparent body 5 fixes the first substrate 2 and the second substrate 3 to each other and seals the light emitting element 4. The first transparent resin can be cured by ultraviolet irradiation, heating, mixing of two liquids, etc. according to its polymerization characteristics or curing characteristics.

[0104] The filling step S7 is a step of filling the through-hole 31 with a second transparent resin having a smaller refractive index than the first transparent resin. In this step, the second transparent resin is discharged into the through-hole 31 from the third surface 3b side of the second substrate 3 using a device such as a dispenser or a slit coater, and is deposited on the first transparent body 5. In this step, the second transparent resin may be filled up to a height position from above the first transparent body 5 to the third surface 3b, or may be filled up to a height position from above the first transparent body 5 between the third surface 3b and the surface of the first transparent body 5 on the third surface 3b side.

[0105] The second formation step S8 is a step of forming the second transparent body 6 by curing the second transparent resin applied onto the first transparent body 5. The second transparent resin can be cured by ultraviolet irradiation, heating, mixing of two liquids, or the like according to its polymerization characteristics or curing characteristics.

[0106] By the above-mentioned manufacturing method, for example, a display device 1 as shown in FIGS. 1 and 2 can be manufactured.

[0107] In the method for manufacturing a display device, a wavelength conversion portion forming step may be performed between the first forming step S6 and the filling step S7.

[0108] The wavelength conversion part forming process is a process of forming the wavelength conversion member 7 located on the surface of the first transparent body 5 on the third surface 3b side. In this process, an insulating resin having phosphors or quantum dots dispersed therein is discharged from the third surface 3b side of the second substrate 3 into the through-hole 31 using a device such as an inkjet or a dispenser, and is deposited on the first transparent body 5. The insulating resin may be an ultraviolet curing resin or a thermosetting resin. The insulating resin deposited on the first transparent body 5 is then cured by a method such as ultraviolet irradiation or heating according to its polymerization characteristics or curing characteristics. The wavelength conversion member 7 can be formed by such a method.

[0109] In the manufacturing method of the display device, after the wavelength conversion portion forming step, a color filter forming step may be performed before the filling step S7. The color filter forming step is a step of forming a color filter 8 located on the surface of the wavelength conversion member 7 on the third surface 3b side. In this step, a resin to which a pigment or a dye is added is discharged into the through hole 31 from the third surface 3b side of the second substrate 3 using a device such as an inkjet or a dispenser, and is deposited on the wavelength conversion member 7. The resin may be an ultraviolet curing resin or a thermosetting resin. Thereafter, the resin deposited on the wavelength conversion member 7 is cured by a method such as ultraviolet irradiation or heating according to its polymerization characteristics or curing characteristics. The color filter 8 can be formed by such a method.

[0110] As described above, according to the display device of the present disclosure, the second transparent body is located on the first transparent body in the through hole of the second base body, has a smaller refractive index than the first transparent body, and is thicker than the first transparent body, so that the light emitted from the light emitting element can be efficiently extracted to the outside. In addition, the directivity of the light radiated to the outside from the through hole is improved. In addition, the light emitting element is hermetically sealed by the first transparent body and the second transparent body, and the heat generated by the light emitting element is efficiently transferred to the second base body and dissipated by the first transparent body and the second transparent body, so that the reliability is improved. Therefore, it is possible to provide a high-definition display device with excellent reliability and light extraction efficiency. In addition, according to the manufacturing method of the display device of the present disclosure, it is possible to manufacture a high-definition display device with excellent reliability and light extraction efficiency.

[0111] Although each embodiment of the present disclosure has been described in detail above, the present disclosure is not limited to the above-described embodiments, and various modifications and improvements are possible within the scope of the gist of the present disclosure. It goes without saying that all or part of the components of each of the above-described embodiments can be appropriately combined within the scope of not being inconsistent.

[0112] The present disclosure can be implemented with the following configurations (1) to (15).

[0113] (1) a first substrate; a second substrate overlaid on the first substrate and having a through hole extending therethrough in the overlapping direction; a light emitting element having a top surface and a side surface, the light emitting element being mounted on a portion of the first base that is exposed in the through hole; a resin material provided in the through hole and sealing the light emitting element; the second substrate is provided on the first substrate with a gap therebetween, A portion of the resin material extends between the first base and the second base.

[0114] (2) The light-emitting element housing structure according to the above configuration (1), wherein the resin material is made of a transparent resin adhesive.

[0115] (3) The light-emitting element housing structure according to the above configuration (1) or (2), wherein the light-emitting element is hermetically sealed within the through hole by the resin material and another resin material located on the resin material, having a smaller refractive index than the resin material, and being thicker than the resin material.

[0116] (4) The light-emitting element housing structure according to any one of the above configurations (1) to (3), wherein the thickness of the extension portion of the resin material extending between the first base and the second base is thinner than the thickness of the portion within the through hole.

[0117] (5) The light-emitting element housing structure according to any one of the above configurations (1) to (4), wherein the second base has a rough surface facing the first base.

[0118] (6) The light-emitting element housing structure according to any one of the above configurations (1) to (5), wherein the first base has a rough surface facing the second base.

[0119] (7) The light-emitting element housing structure according to the above configuration (3), further comprising a wavelength conversion member located between the resin material and the other resin material.

[0120] (8) The light-emitting element housing structure according to the above-mentioned configuration (7), wherein the wavelength conversion member contains a phosphor or a quantum dot.

[0121] (9) The light-emitting element housing structure according to the above configuration (7) or (8), further comprising a color filter located between the wavelength conversion member and the other resin material.

[0122] (10) The light-emitting element housing structure according to any one of the above configurations (1) to (9), wherein the upper surface of the light-emitting element is exposed from the resin material.

[0123] (11) The light-emitting element housing structure according to any one of the above configurations (1) to (10), wherein the through hole has a depth that causes at least a part of the emitted light from the light-emitting element to be reflected multiple times on the inner peripheral surface.

[0124] (12) The light emitting element has an emission light with a maximum intensity inclined with respect to a perpendicular line to the upper surface, The light-emitting element housing structure according to the above-mentioned configuration (11), wherein the maximum intensity light is reflected multiple times on the inner peripheral surface of the through hole.

[0125] (13) The light-emitting element housing structure according to any one of the above configurations (1) to (12), further comprising a light-reflecting film provided on an inner circumferential surface of the through hole.

[0126] (14) The second substrate has a surface opposite to the first substrate as a display surface, The light-emitting element housing structure according to any one of the above configurations (1) to (13), further comprising a light-absorbing film located on the display surface.

[0127] (15) The light-emitting element housing structure according to any one of the above configurations (1) to (14), wherein the light-emitting element is a horizontal connection type light-emitting element having a bottom surface side flip-chip connected. [Industrial Applicability]

[0128] The display device of the present disclosure can be applied to various electronic devices, such as automobile route guidance systems (car navigation systems), ship route guidance systems, aircraft route guidance systems, instrument indicators for vehicles such as automobiles, instrument panels, smartphone terminals, mobile phones, tablet terminals, personal digital assistants (PDAs), video cameras, digital still cameras, electronic organizers, electronic books, electronic dictionaries, personal computers, copiers, game console terminals, televisions, product display tags, price display tags, industrial programmable display devices, car audio, digital audio players, facsimiles, printers, automated teller machines (ATMs), vending machines, medical display devices, digital display wristwatches, smart watches, guidance display devices installed in stations and airports, and advertising signage (digital signage). [Explanation of symbols]

[0129] 1 Display device 2 First base (first board) 2a 1st surface (one main surface, mounting surface) 2aa part (implementation part) 2b Other main surface 2o Recess 2t protrusion 3 Second base (second board) 3a 2nd side 3b 3rd side 3h Inner surface 3o Recess 3t convex part 31 Through hole 31a Inner surface 31b opening 4 Light emitting element 41 Anode terminal 42 Cathode terminal 5 1st transparent body 5e Extension 6 Second transparent body 7,7R,7G,7B Wavelength conversion material 8,8R,8G color filters 9 Light reflective film 10 Light absorbing film 11 pixels 11R, 11G, 11B subpixels 12 Anode electrode 13 Cathode electrode

Claims

1. A first substrate; a second substrate overlaid on the first substrate and having a through hole extending therethrough in a direction of overlay; a light emitting element having a top surface and a side surface, the light emitting element being mounted on a portion of the first base exposed in the through hole; a resin material provided in the through hole and sealing the light emitting element; the second base is provided on the first base with a gap therebetween, A portion of the resin material extends between the first base and the second base.

2. The light-emitting element housing structure according to claim 1 , wherein the resin material is made of a transparent resin adhesive.

3. The light-emitting element housing structure described in claim 1 or 2, wherein the light-emitting element is hermetically sealed within the through hole by the resin material and another resin material located on the resin material, having a smaller refractive index than the resin material, and being thicker than the resin material.

4. The light-emitting element housing structure according to claim 1 , wherein the resin material has an extension portion extending between the first base and the second base that has a thickness smaller than a thickness of a portion inside the through hole.

5. The light-emitting element housing structure according to claim 1 , wherein the second base has a rough surface facing the first base.

6. The light-emitting element housing structure according to claim 1 , wherein the first base has a rough surface facing the second base.

7. The light-emitting element housing structure according to claim 3 , further comprising a wavelength conversion member located between the resin material and the other resin material.

8. The light-emitting element housing structure according to claim 7 , wherein the wavelength conversion member contains a phosphor or a quantum dot.

9. The light-emitting element housing structure according to claim 7 , further comprising a color filter located between the wavelength conversion member and the other resin material.

10. 10. The light-emitting element housing structure according to claim 7, wherein the upper surface of the light-emitting element is exposed from the resin material.

11. 11. The light-emitting element housing structure according to claim 1, wherein the through hole has a depth that causes at least a part of the emitted light from the light-emitting element to be reflected multiple times on the inner peripheral surface.

12. The light emitting element has an emission light with a maximum intensity inclined with respect to a perpendicular line to the upper surface, The light-emitting element housing structure according to claim 11 , wherein the maximum intensity light is reflected multiple times on the inner peripheral surface of the through hole.

13. The light-emitting element housing structure according to any one of claims 1 to 12, further comprising a light-reflecting film provided on an inner peripheral surface of the through hole.

14. the second substrate has a surface opposite to the first substrate as a display surface, The light-emitting element housing structure according to any one of claims 1 to 13, further comprising a light-absorbing film located on the display surface.

15. 15. The light-emitting element housing structure according to claim 1, wherein the light-emitting element is a horizontal connection type light-emitting element having a bottom surface connected by flip-chip bonding.

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