Light-emitting device, display device and lighting device

Abstract

To provide a light-emitting device capable of emitting light having higher uniformity with high efficiency.SOLUTION: This light-emitting device includes: a curved substrate; light sources arranged on the substrate; wall members provided on the substrate so as to surround the light source in a plane perpendicular to a thickness direction of the substrate; wavelength conversion units including a wavelength conversion member arranged opposite the light source in the thickness direction to covert first wavelength light from the light source into second wavelength light, and a transparent member brought into direct or indirect contact with the wavelength conversion member and the wall member; and a curved optical sheet provided at an opposite side to the substrate of the wavelength conversion member. An area occupied by the wavelength conversion member is wider than an area surrounded by the wall member, and overlaps an entire area surrounded by the wall member in the thickness direction. An area occupied by the transparent member is wider than the area occupied by the wavelength conversion member. The wavelength conversion member is provided so as to cause a surface other than a surface brought into contact with the transparent member to be exposed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a light-emitting device, and a display device and a lighting device including the same. [Background technology]

[0002] Light-emitting devices using blue LEDs (Light Emitting Diodes) are used in backlights or lighting devices for liquid crystal display devices. For example, Patent Document 1 discloses a so-called direct-type backlight that generates white light by combining multiple blue LEDs arranged on a substrate with a wavelength conversion sheet that covers the entire substrate. Patent Document 2 discloses a surface light source that generates white light, in which a blue LED, a reflector, a diffusion sheet, and a phosphor layer that performs wavelength conversion are laminated in this order. Patent Document 3 also discloses a light-emitting device that converts the wavelength of light from a light-emitting element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-155999 [Patent Document 2] International Publication No. 2010 / 150516 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-140822 Summary of the Invention

[0004] In such a light emitting device, it is generally strongly desired that the light be efficiently emitted with little unevenness in brightness or color within the surface.

[0005] Therefore, it is desirable to provide a light emitting device that can emit light with high in-plane uniformity at high efficiency, and a display device and lighting device that include the same.

[0006] A light emitting device according to an embodiment of the present disclosure includes a light source, a wavelength conversion unit, and a wall member. The light source is disposed on a substrate. The wavelength conversion unit is disposed opposite the light source in the thickness direction and includes a wavelength conversion member that converts first wavelength light from the light source into second wavelength light, and a transparent member that encapsulates the wavelength conversion member. The wall member is provided on the substrate so as to surround the light source in a plane perpendicular to the thickness direction. Here, the area occupied by the wavelength conversion member is larger than the area surrounded by the wall member and overlaps with the entire area surrounded by the wall member in the thickness direction. The term "wall members arranged to surround each light source" includes wall members that are seamlessly integrated to surround the light source, as well as wall members with slits in some parts. It also includes wall members that are each made up of multiple parts that surround one light source as a whole with small gaps between them. Furthermore, a display device and a lighting device according to an embodiment of the present disclosure include the light-emitting device.

[0007] In a light-emitting device according to an embodiment of the present disclosure, a wavelength conversion member that is disposed opposite a light source and performs wavelength conversion is enclosed in a transparent member. This prevents the wavelength conversion member from coming into contact with the ambient air containing oxygen and moisture, thereby suppressing deterioration of the wavelength conversion member. Furthermore, the area occupied by the wavelength conversion member is larger than the area surrounded by the wall member and overlaps the entire area surrounded by the wall member in the thickness direction. This allows most of the first wavelength light from the light source to be converted to the second wavelength light, improving conversion efficiency.

[0008] Another light emitting device according to an embodiment of the present disclosure includes a light source, a wall member, and a wavelength conversion unit. The light source is disposed on a substrate. The wall member is provided on the substrate so as to surround the periphery of the light source in a plane perpendicular to the thickness direction. The wavelength conversion unit includes a wavelength conversion member disposed opposite the light source in the thickness direction and converting first wavelength light from the light source into second wavelength light, and a transparent member placed so as to directly or indirectly abut the wavelength conversion member and the wall member, respectively. Here, the area occupied by the wavelength conversion member is larger than the area surrounded by the wall member and overlaps the entire area surrounded by the wall member in the thickness direction. In addition, "a transparent member placed so as to abut directly or indirectly against the wavelength conversion member and the wall member, respectively" means that other members, such as adhesive, may be interposed between the wavelength conversion member and the transparent member, and between the multiple wall members and the transparent member.

[0009] In another light-emitting device according to an embodiment of the present disclosure, the wavelength conversion member occupies a larger area than the area surrounded by the wall members and overlaps the entire area surrounded by the wall members in the thickness direction, so that most of the first wavelength light from the light source is converted to second wavelength light, improving conversion efficiency. Furthermore, the transparent member is placed so as to directly or indirectly abut the wavelength conversion member and each of the wall members, ensuring high heat dissipation and suppressing deterioration of the wavelength conversion member. Furthermore, the distance between the light source and the wavelength conversion member is reduced, improving luminance efficiency.

[0010] According to a light-emitting device as an embodiment of the present disclosure, it is possible to improve conversion efficiency while suppressing deterioration of the wavelength conversion member. Therefore, it is possible to efficiently emit light with little in-plane unevenness in brightness or color. Therefore, a display device using this light-emitting device can exhibit excellent display performance, such as color reproducibility. Furthermore, an illumination device using this light-emitting device can provide more uniform illumination of an object. Note that the effects of the present disclosure are not limited to these, and may include any of the effects described below. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view illustrating an example of the overall configuration of a light emitting device according to a first embodiment of the present disclosure. [Figure 2] 2 is an enlarged perspective view showing the configuration of the light-emitting unit shown in FIG. 1. FIG. [Figure 3] 2 is a cross-sectional view illustrating a configuration of a main part of the light emitting device shown in FIG. [Figure 4] 4 is an enlarged cross-sectional view showing the configuration of the light-emitting section shown in FIG. 3. FIG. [Figure 5] 1. FIG. 4 is a cross-sectional view illustrating a configuration of a first modified example of the light-emitting section illustrated in FIG. [Figure 6] 1. FIG. 4 is a cross-sectional view illustrating a configuration of a second modified example of the light-emitting section illustrated in FIG. [Figure 7] 1. FIG. 4 is a cross-sectional view illustrating a configuration of a third modified example of the light-emitting section illustrated in FIG. [Figure 8] FIG. 10 is a cross-sectional view illustrating an example of a main configuration of a light emitting device according to a second embodiment of the present disclosure. [Figure 9] FIG. 10 is a perspective view illustrating an appearance of a display device according to a third embodiment of the present disclosure. [Figure 10] FIG. 10 is an exploded perspective view of the main body shown in FIG. 9. [Figure 11] FIG. 11 is an exploded perspective view of the panel module shown in FIG. [Figure 12A] 1 is a perspective view illustrating the appearance of a tablet terminal device equipped with a display device of the present disclosure. [Figure 12B] FIG. 10 is a perspective view illustrating the appearance of another tablet terminal device equipped with a display device of the present disclosure. [Figure 13] 1 is a perspective view illustrating the appearance of a first lighting device including a light-emitting device according to the present disclosure. [Figure 14] FIG. 10 is a perspective view illustrating the appearance of a second lighting device including the light-emitting device of the present disclosure. [Figure 15] FIG. 10 is a perspective view illustrating the appearance of a third lighting device including the light-emitting device of the present disclosure. [Figure 16A] FIG. 10 is a characteristic diagram showing a chromaticity distribution immediately above a wavelength conversion unit in Experimental Example 1-1. [Figure 16B] FIG. 10 is a characteristic diagram showing a chromaticity distribution immediately above a wavelength conversion unit in Experimental Example 1-2. [Figure 16C] FIG. 10 is a characteristic diagram illustrating a chromaticity distribution immediately above a wavelength conversion unit in Experimental Example 1-3. [Figure 17] FIG. 10 is a characteristic diagram showing, by curves, changes in chromaticity immediately above the wavelength conversion unit in Experimental Examples 1-1 and 1-3. [Figure 18A] FIG. 10 is a characteristic diagram showing the chromaticity distribution after passing through an optical sheet in Experimental Example 1-1. [Figure 18B] FIG. 10 is a characteristic diagram illustrating a chromaticity distribution after passing through an optical sheet in Experimental Example 1-2. [Figure 18C] FIG. 10 is a characteristic diagram illustrating a chromaticity distribution after passing through an optical sheet in Experimental Example 1-3. [Figure 19] FIG. 10 is a characteristic diagram showing, by curves, changes in chromaticity after passing through an optical sheet in Experimental Examples 1-1 and 1-3. [Figure 20] FIG. 10 is a cross-sectional view illustrating a configuration example of a light-emitting device according to a fourth modification of the present disclosure. [Figure 21] FIG. 10 is a perspective view illustrating a configuration example of a light-emitting section according to a fifth modified example of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The description will be made in the following order. 1. First embodiment and its modifications 10 is an example of a light emitting device having a wavelength conversion unit in which a wavelength conversion member is enclosed inside a transparent member. 2. Second embodiment 10 is an example of a light emitting device in which a wavelength conversion member is placed on a holder via a transparent member. 3. Third embodiment (display device; liquid crystal display device) 4. Display device application examples 5.Application examples of lighting equipment 6. Experimental Example 7. Other Modifications

[0013] <1. First embodiment> [Configuration of light-emitting device 1] FIG. 1 is a perspective view illustrating an example of the overall configuration of a light-emitting device 1 according to a first embodiment of the present disclosure. FIG. 2 is a perspective view illustrating an enlarged view of a light-emitting unit 11, which is a main part of the light-emitting device 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1. FIG. 4 is a cross-sectional view illustrating a further enlarged view of one light-emitting unit 11. The light-emitting device 1 is used, for example, as a backlight that illuminates a transmissive liquid crystal panel from behind, or as a lighting device for indoor use. As shown in FIG. 1, the light-emitting device 1 includes, for example, a plurality of light-emitting units 11 arranged in a matrix on a substrate 10, and a single optical sheet 50 commonly disposed opposite the plurality of light-emitting units 11. Note that FIG. 1 illustrates an example in which the plurality of light-emitting units 11 are arranged along both the X-axis direction and the Y-axis direction, which are orthogonal to each other; however, the present disclosure is not limited thereto.

[0014] In this specification, the distance direction between the substrate 10 and the optical sheet 50 is defined as the Z-axis direction (front-to-back direction or thickness direction), the up-down direction on the main surfaces (widest surfaces) of the substrate 10 and the optical sheet 50 is defined as the X-direction, and the left-to-right direction is defined as the Y-direction.

[0015] (Configuration of light-emitting unit 11) 2 to 4, the configuration of the light-emitting section 11 will be described in detail. Each of the plurality of light-emitting sections 11 has a light-emitting element 12, a holder 20, and a wavelength conversion unit 30. Here, the light-emitting element 12 is a specific example corresponding to the "light source" in the present disclosure, the holder 20 is a specific example corresponding to the "wall member" in the present disclosure, and the wavelength conversion unit 30 is a specific example corresponding to the "wavelength conversion unit" in the present disclosure.

[0016] The light-emitting elements 12 are arranged in a matrix on the surface 10S of the substrate 10. The light-emitting elements 12 are point light sources, and specifically, are constituted by LEDs (Light Emitting Diodes). The light-emitting elements 12 have an optical axis CL that coincides with, for example, the Z-axis direction. The light-emitting elements 12 face, for example, the back surface 30S2 (see FIG. 4) of the wavelength conversion unit 30. The light-emitting elements 12 may have a package structure in which a light-emitting layer is encapsulated in a resin layer, or may be flip-chip LEDs (light-emitting diodes) in which the light-emitting layer is exposed.

[0017] The holder 20 is provided on the surface 10S of the substrate 10 so as to surround one light-emitting element 12 in an XY plane perpendicular to the Z-axis direction, forming an air layer between the light-emitting element 12 and the wavelength conversion unit 30. That is, the light-emitting element 12 is provided on the surface 10S of the substrate 10 at an opening located at the center of the holder 20. The center position of the holder 20 in the XY plane may coincide with the optical axis CL, for example. The holder 20 may have a shape that surrounds the light-emitting element 12 as a whole without any gaps, or may have a slit formed in part of itself and be partially interrupted. The holder 20 may also be composed of multiple separate parts that collectively surround one light-emitting element 12 with small gaps between them. Furthermore, in the present embodiment, one light-emitting element 12 is provided for one light-emitting unit 11, and the light-emitting element 12 is surrounded by the holder 20, but the present disclosure is not limited thereto. For example, a plurality of light emitting elements 12 may be provided for one light emitting section 11 , and the plurality of light emitting elements 12 may be surrounded by the holder 20 .

[0018] The holder 20 includes an inner wall surface 21 facing the light-emitting element 12 and an upper surface 22 located on the opposite side from the substrate 10. The inner wall surface 21 is a reflective surface that reflects the first wavelength light from the light-emitting element 12, and is inclined so as to move away from the light-emitting element 12 as it extends from the substrate 10 toward the wavelength conversion unit 30. Therefore, the area of ​​the region R21U surrounded by the upper edge 21TU of the inner wall surface 21 in the XY plane is larger than the area of ​​the region R21B surrounded by the lower edge 21TB of the inner wall surface 21 in the XY plane. In other words, the area of ​​the region R21 in the XY plane of the space surrounded by the inner wall surface 21 of the holder 20 gradually increases as it extends from the substrate 10 toward the wavelength conversion unit 30.

[0019] The holder 20 is formed, for example, by cutting out a plate-shaped member, or by injection molding or hot press molding. A highly thermally conductive material having a thermal conductivity higher than that of the wavelength conversion unit 30 is desirable as the constituent material of the holder 20. Specifically, a metal material containing at least one of aluminum (Al) and copper (Cu) can be used. Alternatively, the constituent material of the holder 20 can be a thermoplastic resin in addition to a metal material. Examples of the thermoplastic resin include polycarbonate resin, acrylic resin such as PMMA (polymethyl methacrylate resin), polyester resin such as PET (polyethylene terephthalate), amorphous copolymer polyester resin such as MS (copolymer of methyl methacrylate and styrene), polystyrene resin, and polyvinyl chloride resin. Furthermore, as in the light-emitting unit 11A as a first modified example shown in FIG. 5, a thin film 21F made of a highly reflective material, such as a silver vapor deposition film, an aluminum vapor deposition film, or a multilayer reflective film, may be formed on the inner wall surface 21 of the holder 20. This is because the reflectance of the inner wall surface 21 is improved, and the light emitting efficiency of the light emitting device 1 is further improved. Note that the high reflectance material refers to a material having a reflectance higher than the reflectance of the transparent member 32 of the wavelength conversion unit 30, for example.

[0020] In this light emitting device 1, the holder 20 including the inclined inner wall surface 21 is provided, so that the first wavelength light emitted from the light emitting element 12 is reflected by the inner wall surface 21 and then travels toward the wavelength conversion unit 30. Therefore, the inner wall surface 21 of the holder 20 can tilt the first wavelength light emitted from the light emitting element 12 in an oblique direction (a direction inclined with respect to the Z-axis direction) toward the front direction (+Z direction), contributing to an improvement in front brightness.

[0021] In the light emitting device 1, the dimension W21 in the X-axis and Y-axis directions of the region R21U is, for example, 3.5 mm, and the angle that the inner wall surface 21 forms with respect to the surface 10S of the substrate 10 is, for example, 45°. The height H20 (dimension in the Z-axis direction) of the holder 20 is, for example, 0.55 mm. Furthermore, the dimension W12 in the X-axis and Y-axis directions of the light emitting element 12 is, for example, 1 mm, and the height H12 of the light emitting point of the light emitting element 12 is, for example, 0.3 mm.

[0022] The upper surface 22 of the holder 20 is in direct or indirect contact with a rear surface 30S2 (described later) of the wavelength conversion unit 30. This allows the holder 20 to function as a holder for holding the wavelength conversion unit 30. The phrase "the upper surface 22 of the holder 20 is in direct contact with the rear surface 30S2 of the wavelength conversion unit 30" refers to a state in which the upper surface 22 and the rear surface 30S2 are directly joined together without any other member interposed therebetween, for example, by fusion or welding. The phrase "the upper surface 22 of the holder 20 is in direct contact with the rear surface 30S2 of the wavelength conversion unit 30" refers to a state in which the upper surface 22 and the rear surface 30S2 are indirectly joined together with any other member interposed therebetween, such as an adhesive or a pressure-sensitive adhesive.

[0023] The wavelength conversion unit 30 is disposed between the light emitting element 12 and the optical sheet 50 in the Z-axis direction, and includes a wavelength conversion member 31 and a transparent member 32 that contains the wavelength conversion member 31. The wavelength conversion unit 30 is disposed so as to face the light emitting element 12 surrounded by the holder 20 in the Z-axis direction, i.e., so as to cover the area directly above the light emitting element 12. The wavelength conversion unit 30 converts the wavelength of light (first wavelength light) incident on the back surface 30S2 from the light emitting element 12 in the wavelength conversion member 31, and emits second wavelength light (converted light) from the front surface 30S1, thereby improving, for example, color development characteristics.

[0024] The wavelength conversion member 31 contains a phosphor (fluorescent substance) such as a fluorescent pigment or fluorescent dye, or a light-emitting body having a wavelength conversion effect, such as quantum dots. The wavelength conversion member 31 is, for example, a resin containing a fluorescent substance or a light-emitting body processed into a sheet shape.

[0025] The wavelength conversion member 31 is excited by first wavelength light from the light-emitting element 12 that passes through the back surface 30S2 and enters the wavelength conversion member 31 from the back surface 31S. The wavelength conversion member 31 converts the wavelength of the first wavelength light based on the principle of fluorescence or the like, and emits second wavelength light having a wavelength (second wavelength) different from the first wavelength from the front surface 31S1. Here, the first wavelength and the second wavelength are not particularly limited. For example, in the case of a display device application, the first wavelength light may be blue light (e.g., wavelength of about 440 to 460 nm), and the second wavelength light may be red light (e.g., wavelength of 620 to 750 nm) or green light (e.g., wavelength of 495 to 570 nm). That is, if the light-emitting element 12 is a blue light source, the wavelength conversion member 31 converts the blue light into red light or green light.

[0026] The wavelength conversion member 31 preferably contains quantum dots. Quantum dots are particles with a major axis of approximately 1 nm to 100 nm and have discrete energy levels. Since the energy state of quantum dots depends on their size, it is possible to freely select the emission wavelength by changing the size. Furthermore, the emission light of quantum dots has a narrow spectral width. The color gamut can be expanded by combining light with such sharp peaks. Therefore, by using quantum dots as a wavelength conversion material, it is possible to easily expand the color gamut. Furthermore, quantum dots have high responsiveness, allowing for efficient use of the light from the light-emitting element 12. In addition, quantum dots are highly stable. Quantum dots are, for example, compounds of Group 12 and Group 16 elements, compounds of Group 13 and Group 16 elements, or compounds of Group 14 and Group 16 elements, such as CdSe, CdTe, ZnS, CdS, PdS, PbSe, or CdHgTe.

[0027] In the XY plane, the region R31 occupied by the wavelength conversion member 31 is larger than the region R21U surrounded by the upper edge 21TU of the holder 20, and overlaps with the entire region R21U surrounded by the holder 20 in the Z-axis direction (see FIG. 4). That is, the edge of the wavelength conversion member 31 in the XY plane extends beyond the upper edge 21TU of the holder 20. This prevents the first wavelength light from the light emitting elements 12 from directly entering the optical sheet 50 without passing through the wavelength conversion member 31. That is, all of the first wavelength light from the light emitting elements 12 enters the wavelength conversion member 31 via the transparent member 32, undergoes wavelength conversion, and then travels toward the optical sheet 50. As a result, brightness and color unevenness are sufficiently reduced.

[0028] In the light emitting device 1, the dimension W31 in the X-axis direction and the Y-axis direction of the region R31 occupied by the wavelength converting member 31 is, for example, 3 mm, and the dimension W32 in the X-axis direction and the Y-axis direction of the region R32 occupied by the transparent member 32 is, for example, 3.8 mm. The thickness H31 of the wavelength converting member 31 is, for example, 0.2 mm, and the thickness H32 of the transparent member 32 is, for example, 0.5 mm.

[0029] The transparent member 32 seals the wavelength conversion member 31 to protect it from contact with the outside air containing oxygen and moisture, and is made of a transparent material such as glass or resin. The wavelength conversion member 31 functions as an effective part that converts the wavelength of light from the light emitting element 12, whereas the transparent member 32 can be said to be an ineffective part that transmits the incident light without converting the wavelength of the incident light.

[0030] The wavelength conversion unit 30 is placed on the upper surface 22 of the holder 20. That is, as described above, the back surface 30S2 of the wavelength conversion unit 30 (transparent member 32) directly or indirectly abuts against the upper surface 22 of the holder 20, so that the wavelength conversion unit 30 is held by the holder 20. In this light emitting device 1, a plurality of wavelength conversion members 31 (wavelength conversion units 30) are provided, each divided for each light emitting section 11. Therefore, compared with, for example, a single wavelength conversion sheet that extends over the entire surface 10S of the substrate 10, the amount of material used is reduced, which is advantageous in terms of cost reduction and weight reduction.

[0031] Furthermore, in the light emitting device 1, as in the light emitting section 11B as a second modified example shown in FIG. 6, a low-reflection layer 33 having a reflectance lower than that of the inner wall surface 21 may be provided so as to cover the rear surface 30S2. The first wavelength light that reaches the rear surface 30S2 directly from the light emitting element 12 or that reaches the rear surface 30S2 after being reflected by the inner wall surface 21 is less likely to be reflected by the rear surface 30S2. This is to reduce the amount of first wavelength light emitted from the light emitting element 12 that is wavelength converted by the wavelength conversion member 31.

[0032] 7, the light emitting device 1 may be provided with a wavelength-selective reflective layer 34 so as to cover the rear surface 30S2. This is because it is possible to remove light components in unnecessary wavelength ranges and select light components in desired wavelength ranges to be incident on the wavelength conversion member 31.

[0033] The optical sheet 50 is provided opposite the surface 30S1 of the wavelength conversion unit 30, and includes, for example, a diffusion plate, a diffusion sheet, a lens film, a polarization separation sheet, etc. By providing such an optical sheet 50, it becomes possible to direct the light emitted obliquely from the light emitting element 12 or the wavelength conversion unit 30 toward the front, thereby further increasing the front brightness.

[0034] [Actions and Effects of Light-Emitting Device 1] In the light emitting device 1, the light emitting element 12 of the light emitting section 11 is a point light source, and therefore the first wavelength light emitted from the light emitting element 12 spreads in all directions by 360° from the light emitting center of the light emitting element 12. The first wavelength light emitted from the light emitting element 12 is directly incident on the rear surface 30S2 of the wavelength conversion unit 30, or is reflected by the inner wall surface 21 of the holder 20 and then incident on the rear surface 30S2. The first wavelength light incident on the wavelength conversion unit 30 is converted to second wavelength light by the wavelength conversion member 31 and then emitted from the front surface 30S1, and finally passes through the optical sheet 50 to be observed as emitted light.

[0035] In the light-emitting device 1 of this embodiment, the wavelength conversion member 31, which is disposed opposite the light-emitting element 12 and performs wavelength conversion, is enclosed in the transparent member 32. This prevents the wavelength conversion member 31 from coming into contact with the outside air containing oxygen and moisture, thereby suppressing deterioration of the wavelength conversion member 31. Furthermore, the region R31 occupied by the wavelength conversion member 31 is wider than the region R21U surrounded by the holder 20 and overlaps with the entire region R21U in the thickness direction. This allows most of the first wavelength light from the light-emitting element 12 to be converted to the second wavelength light without leakage, thereby suppressing color unevenness and improving the conversion efficiency of each light-emitting unit 11. This also improves color unevenness and luminous efficiency of the light-emitting device 1 as a whole.

[0036] In the light emitting device 1 of this embodiment, the wavelength conversion unit 30 is placed on the upper surface 22 so as to be in direct or indirect contact with the holder 20, so that heat from the wavelength conversion member 31 is easily absorbed by the holder 20 via the transparent member 32 and released to the outside. This ensures high heat dissipation and suppresses deterioration of the wavelength conversion member 31 due to overheating. Furthermore, compared to when the wavelength conversion unit 30 is spaced apart from the holder 20, the distance between the light emitting element 12 and the wavelength conversion member 31 is narrower, so improved luminance efficiency can be expected.

[0037] In the light emitting device 1 of the present embodiment, the holder 20 has a reflecting function of reflecting the first wavelength light from the light emitting element 12 toward the wavelength conversion unit 30, as well as a holding function of holding the wavelength conversion unit 30. This results in a more compact configuration, which is advantageous for miniaturization, high integration, and cost reduction.

[0038] In this way, the light emitting device 1 can improve conversion efficiency while suppressing deterioration of the wavelength conversion member 31. Therefore, light can be efficiently emitted with little in-plane unevenness in brightness or color. Therefore, a display device using this light emitting device 1 can exhibit excellent display performance, such as color reproducibility. Furthermore, an illumination device using this light emitting device 1 can provide more uniform illumination to an object.

[0039] <2. Second embodiment> [Configuration of light-emitting device 2] 8 is an enlarged cross-sectional view showing a main part of a light emitting device 2 according to a second embodiment of the present disclosure. The light emitting device 2 has a wavelength conversion unit 30A instead of the wavelength conversion unit 30. In the wavelength conversion unit 30A, the wavelength conversion member 31 is not sealed with a transparent member 32, but is placed on a sheet-like or plate-like transparent member 35. The transparent member 35 has a front surface 35S1 on which the wavelength conversion member 31 is placed, and a back surface 35S2 that directly or indirectly abuts against the upper surface 22 of the holder 20. Except for these points, the light emitting device 2 has the same configuration as the light emitting device 1 according to the first embodiment.

[0040] [Action and effect of light-emitting device 2] In such a light emitting device 2, the region R31 occupied by the wavelength conversion member 31 is also larger than the region R21U surrounded by the holder 20 and overlaps with the entire region R21U in the thickness direction. Therefore, most of the first wavelength light from the light emitting element 12 is converted into the second wavelength light without leakage, thereby improving the conversion efficiency of each light emitting section 11 while suppressing the occurrence of color unevenness. Therefore, the color unevenness and light emitting efficiency of the light emitting device 2 as a whole are also improved.

[0041] In the light emitting device 2, the wavelength conversion unit 30A is placed on the upper surface 22 so as to be in direct or indirect contact with the holder 20, so that heat from the wavelength conversion member 31 is easily absorbed by the holder 20 via the transparent member 35 and released to the outside. This ensures high heat dissipation and suppresses deterioration of the wavelength conversion member 31 due to overheating. Furthermore, compared to when the wavelength conversion unit 30 is spaced apart from the holder 20, the distance between the light emitting element 12 and the wavelength conversion member 31 is narrower, which is expected to improve luminance efficiency.

[0042] In the light emitting device 2 of the present embodiment, the holder 20 has a reflecting function of reflecting the first wavelength light from the light emitting element 12 toward the wavelength conversion unit 30, as well as a holding function of holding the wavelength conversion unit 30. This results in a more compact configuration, which is advantageous for miniaturization, high integration, and cost reduction.

[0043] Thus, the light emitting device 2 is expected to have the same effects as the light emitting device 1.

[0044] <3. Third Embodiment> 9 shows the appearance of a display device 101 according to a third embodiment of the present technology. This display device 101 includes a light-emitting device 1 and is used, for example, as a thin television device, and has a configuration in which a flat main body 102 for displaying images is supported by a stand 103. Note that the display device 101 is used as a floor-mounted type by placing it on a horizontal surface such as a floor, shelf, or stand with the stand 103 attached to the main body 102, but it can also be used as a wall-mounted type with the stand 103 detached from the main body 102.

[0045] 10 is an exploded view of the main body 102 shown in FIG. 9. The main body 102 has, for example, a front exterior member (bezel) 111, a panel module 112, and a rear exterior member (rear cover) 113, in this order from the front side (viewer side). The front exterior member 111 is a frame-shaped member that covers the front peripheral edge of the panel module 112, and a pair of speakers 114 are arranged below it. The panel module 112 is fixed to the front exterior member 111, and a power supply board 115 and a signal board 116 are mounted on the rear surface of the panel module 112, and a mounting bracket 117 is fixed to the rear surface of the panel module 112. The mounting bracket 117 is used to attach a wall-mount bracket, boards, etc., and the stand 103. The rear exterior member 113 covers the rear and side surfaces of the panel module 112.

[0046] Fig. 11 is an exploded view of the panel module 112 shown in Fig. 10. The panel module 112 has, for example, from the front side (viewer side), a front housing (top chassis) 121, a liquid crystal panel 122, a frame-shaped member (middle chassis) 123, an optical sheet 50, a light-emitting device 1 in which a plurality of light-emitting units 11 are arranged on a substrate 10, a rear housing (back chassis) 124, and a timing controller substrate 127 in this order.

[0047] The front housing 121 is a frame-shaped metal part that covers the front peripheral edge of the liquid crystal panel 122. The liquid crystal panel 122 has, for example, a liquid crystal cell 122A, a source substrate 122B, and a flexible substrate 122C such as a COF (Chip On Film) that connects these together. The frame-shaped member 123 is a frame-shaped resin part that holds the liquid crystal panel 122 and the optical sheet 50. The rear housing 124 is a metal part made of iron (Fe) or the like that houses the liquid crystal panel 122, the frame-shaped member 123, and the light emitting device 1. A timing controller board 127 is also mounted on the rear surface of the rear housing 124.

[0048] In this display device 101, an image is displayed by selectively transmitting light from the light emitting device 1 through the liquid crystal panel 122. As described in the first embodiment, the display device 101 is provided with the light emitting device 1 having excellent light emitting efficiency and improved in-plane color uniformity, and therefore the display quality of the display device 101 is improved.

[0049] In the above embodiment, the display device 101 is described as being equipped with the light-emitting device 1 according to the first embodiment, but the display device 101 may be equipped with the light-emitting device 2 according to the second embodiment instead of the light-emitting device 1.

[0050] <4. Examples of display device applications> Hereinafter, an example of application of the above-described display device 101 to electronic devices will be described. Examples of electronic devices include television devices, digital cameras, notebook personal computers, portable terminal devices such as mobile phones, and video cameras. In other words, the above-described display device can be applied to electronic devices in all fields that display externally input video signals or internally generated video signals as images or videos.

[0051] Fig. 12A shows the appearance of a tablet terminal device to which the display device 101 of the above embodiment is applied. Fig. 12B shows the appearance of another tablet terminal device to which the display device 101 of the above embodiment is applied. Each of these tablet terminal devices has, for example, a display unit 210 and a non-display unit 220, and the display unit 210 is configured by the display device 101 of the above embodiment.

[0052] <5. Application examples of lighting equipment> 13 and 14 show the appearance of a tabletop lighting device to which the light emitting device 1 of the above embodiment and the like are applied. This lighting device has, for example, a lighting unit 843 attached to a support 842 provided on a base 841, and this lighting unit 843 is composed of the light emitting device 1 and the like. By making the substrate 10 and the optical sheet 50 and the like curved, the lighting unit 843 can be made into any shape, such as a cylindrical shape as shown in FIG. 13 or a curved surface shape as shown in FIG. 14.

[0053] 15 shows the appearance of an indoor lighting device to which the light emitting device 1 of the above embodiment and the like are applied. This lighting device has lighting units 844 configured with the light emitting device 1 and the like. The lighting units 844 are arranged in an appropriate number and at appropriate intervals on a ceiling 850A of a building. Note that the lighting units 844 are not limited to being installed on the ceiling 850A, but can also be installed in any location such as a wall 850B or a floor (not shown) depending on the application.

[0054] In these lighting devices, illumination is provided by light from the light emitting device 1 or the like. Here, the lighting quality is improved because the lighting device 1 or the like has excellent light emitting efficiency and improved uniformity of the in-plane luminance distribution.

[0055] 6. Experimental Example (Experimental Examples 1-1 to 1-3) Samples of the light-emitting device 1 including the light-emitting section 11 described in the first embodiment were fabricated, and the state of color unevenness was compared. Specifically, the light-emitting element 12 in one light-emitting section 11 in the light-emitting device 1 was turned on, and the chromaticity distribution directly above the wavelength conversion unit 30 was measured. The results are shown in FIGS. 16A to 16C and 17, respectively. FIGS. 16A to 16C are characteristic diagrams showing chromaticity distribution in the XY plane, and correspond to Experimental Examples 1-1 to 1-3, respectively. In FIGS. 16A to 16C, the horizontal axis represents the position in the X-axis direction, and the vertical axis represents the position in the Y-axis direction. FIG. 17 is a characteristic diagram showing the change in chromaticity in the X-axis direction as a curve. In FIG. 17, the horizontal axis represents the distance (mm) from the optical axis CL in the X-axis direction, and the vertical axis represents chromaticity.

[0056] Furthermore, for each sample of the light-emitting device 1, 25 light-emitting units 11 were arranged at 11 mm intervals (5 columns x 5 rows), and all of the light-emitting units 11 were turned on to measure the chromaticity distribution of the light transmitted through the optical sheet 50. The results are shown in FIGS. 18A to 18C and 19, respectively. FIGS. 18A to 18C are characteristic diagrams showing the chromaticity distribution in the XY plane, and correspond to Experimental Examples 1-1 to 1-3, respectively. In FIGS. 18A to 18C, the horizontal axis represents the position in the X-axis direction, and the vertical axis represents the position in the Y-axis direction. FIG. 19 is a characteristic diagram showing the change in chromaticity in the X-axis direction as a curve. In FIG. 19, the horizontal axis represents the distance (mm) from the optical axis CL in the X-axis direction, and the vertical axis represents chromaticity.

[0057] Here, the dimension W31 of the wavelength conversion member 31 was 3.8 mm in Experimental Example 1-1, 4.0 mm in Experimental Example 1-2, and 3.5 mm in Experimental Example 1-3 (see FIG. 4). Other conditions were the same in Experimental Examples 1-1 to 1-3. Specifically, the wavelength conversion unit 30 had a thickness H31 of 0.2 mm and a thickness H32 of 0.5 mm. Quantum dots were used for the wavelength conversion member 31, and glass was used for the transparent member 32. The holder 20 had a dimension W21 of 3.5 mm, a height H20 of 0.55 mm, and an angle of the inner wall surface 21 relative to the surface 10S of the holder 20 of 30°. The light-emitting element 12 used was a blue LED package with a dimension W12 of 1 mm and a height H12 of the light-emitting point of 0.3 mm. Furthermore, the distance OD from the surface 10S of the substrate 10 to the rear surface of the optical sheet 50 (the surface facing the light-emitting unit 11) was 10 mm.

[0058] 16C and 17 (curve 17C3), in Experimental Example 1-3, it was confirmed that blue light leaked from near the edge of wavelength conversion member 31. This is thought to be because the dimension W31 of region R31 and the dimension W21 of region R21U were the same. In other words, this is because part of the blue light from light-emitting element 12 was transmitted through transparent member 32 covering the edge of wavelength conversion member 31 and emitted from surface 30S1 without being wavelength-converted.

[0059] 16A and 17 (curve 17C1), in Experimental Examples 1-1 and 1-2, leakage of blue light was not visible even near the edge of wavelength conversion member 31. This is because the dimension W31 of region R31 was larger than the dimension W21 of region R21U, and region R31 occupied by wavelength conversion member 31 overlapped with the entire region R21U.

[0060] 18A to 18C and 19, color unevenness in the XY plane after light passes through optical sheet 50 including a diffuser plate is reduced more in Experimental Examples 1-1 and 1-2 than in Experimental Example 1-3. In Fig. 19, curve 19C1 corresponds to Experimental Example 1-1, and curve 19C3 corresponds to Experimental Example 1-3.

[0061] Thus, it was confirmed that the present disclosure can sufficiently reduce color unevenness.

[0062] <7. Other Modifications> Although the present disclosure has been described above with reference to the embodiments and modified examples, the present disclosure is not limited to the above-described embodiments, etc., and various modifications are possible. For example, the materials and thicknesses of the layers described in the above-described embodiments are not limited, and other materials and thicknesses may be used.

[0063] (Fourth Modification) In addition, in the above-described embodiments, the wavelength conversion unit 30 is directly or indirectly brought into contact with the holder 20. However, as in the light-emitting device 3 shown in FIG. 20, the wavelength conversion unit 30 may be placed on a transparent member 36, and the transparent member 36 may be spaced apart from the upper surface 22 of the holder 20.

[0064] (Fifth Modification) In addition, in the above-described embodiments, the planar shape of the wavelength conversion unit 30 and the planar shapes of the outer edge and opening of the holder 20 are square, but the present technology is not limited to this. For example, as in the light-emitting section 11D shown in FIG. 21 , the planar shape of the wavelength conversion unit 30 and the planar shapes of the outer edge and opening of the holder 20 may be circular. Alternatively, they may be polygonal other than a rectangle, such as a hexagon. In this case, the planar shapes of all the light-emitting sections in the light-emitting device may be the same shape, or several different shapes.

[0065] Furthermore, for example, in the above embodiments, the configurations of the light emitting devices 1 to 3 and the display device 101 (television device) have been specifically described, but it is not necessary to include all of the components, and other components may also be included.

[0066] It should be noted that the effects described in this specification are merely examples and are not limited to those described, and other effects may also be achieved. Furthermore, the present technology may have the following configurations. (1) a light source disposed on the substrate; a wavelength conversion unit disposed opposite each of the light sources in the thickness direction, the wavelength conversion unit including a wavelength conversion member that converts first wavelength light from the light sources into second wavelength light, and a transparent member that contains the wavelength conversion member; a wall member provided on the substrate so as to surround the light source in a plane perpendicular to the thickness direction; and The area occupied by the wavelength conversion member is wider than the area surrounded by the wall member and overlaps with the entire area surrounded by the wall member in the thickness direction. Light-emitting device. (2) The wall member directly or indirectly abuts against the wavelength conversion unit and holds the wavelength conversion unit. The light emitting device according to (1) above. (3) Further, the light source includes a light diffusing member that covers the plurality of light sources in common, The wavelength conversion unit is disposed between the plurality of light sources and the light diffusing member in the thickness direction. The light emitting device according to (1) or (2) above. (4) the wall member has an inner wall surface that reflects the first wavelength light from the light source, The inner wall surface is inclined so as to be farther away from the light source as it goes from the substrate toward the wavelength conversion unit. The light emitting device according to any one of (1) to (3) above. (5) The wall member includes a highly thermally conductive material having a thermal conductivity higher than that of the wavelength converting unit. The light emitting device according to any one of (1) to (4) above. (6) The highly thermally conductive material includes at least one of aluminum and copper. The light-emitting device according to (5) above. (7) the wall member has an inner wall surface that reflects the first wavelength light from the light source, The inner wall surface is a surface of a highly reflective material having a reflectance higher than that of the wavelength conversion unit. The light emitting device according to any one of (1) to (6) above. (8) The highly reflective material includes at least one of aluminum and silver. The light-emitting device according to (7) above. (9) The light source is a flip-chip LED (light-emitting diode). The light emitting device according to any one of (1) to (8) above. (10) An air gap is provided between the light source and the wavelength conversion unit. The light emitting device according to any one of (1) to (9) above. (11) The wavelength conversion member includes quantum dots. The light emitting device according to any one of (1) to (10) above. (12) the wall member has an inner wall surface that reflects the first wavelength light from the light source, A low-reflection layer having a reflectance lower than that of the inner wall surface is provided on a light incident surface of the wavelength conversion unit facing the light source. The light emitting device according to any one of (1) to (11) above. (13) A wavelength selective reflection layer is provided on a light incident surface of the wavelength conversion unit facing the light source. The light emitting device according to any one of (1) to (12) above. (14) All of the first wavelength light from the light source passes through the transparent member and enters the wavelength conversion member. The light emitting device according to any one of (1) to (13) above. (15) a light source disposed on the substrate; a wall member provided on the substrate so as to surround the periphery of the light source in a plane perpendicular to the thickness direction; a wavelength conversion unit including: a wavelength conversion member disposed opposite the light source in the thickness direction and configured to convert first wavelength light from the light source into second wavelength light; and a transparent member placed so as to be in direct or indirect contact with the wavelength conversion member and the wall member, respectively; and The area occupied by the wavelength conversion member is wider than the area surrounded by the wall member and overlaps with the entire area surrounded by the wall member in the thickness direction. Light-emitting device. (16) a liquid crystal panel and a light emitting device on the rear side of the liquid crystal panel, The light emitting device comprises: a plurality of light sources disposed on a substrate; a plurality of wavelength conversion units arranged to face each of the plurality of light sources in a thickness direction, each including a wavelength conversion member that converts first wavelength light from the plurality of light sources into second wavelength light, and a transparent member that contains the wavelength conversion member; a plurality of wall members provided on the substrate so as to surround each of the plurality of light sources in a plane perpendicular to the thickness direction; and The area occupied by the wavelength conversion member is wider than the area surrounded by the wall member and overlaps with the entire area surrounded by the wall member in the thickness direction. have Display device. (17) A light emitting device is provided, The light emitting device comprises: a plurality of light sources disposed on a substrate; a plurality of wavelength conversion units arranged to face each of the plurality of light sources in a thickness direction, each including a wavelength conversion member that converts first wavelength light from the plurality of light sources into second wavelength light, and a transparent member that contains the wavelength conversion member; a plurality of wall members provided on the substrate so as to surround each of the plurality of light sources in a plane perpendicular to the thickness direction; and The area occupied by the wavelength conversion member is wider than the area surrounded by the wall member and overlaps with the entire area surrounded by the wall member in the thickness direction. have Lighting equipment.

[0067] This application claims priority based on Japanese Patent Application No. 2016-60359, filed on March 24, 2016, in the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0068] Those skilled in the art will recognize that various modifications, combinations, subcombinations, and variations may occur depending on design requirements and other factors, and are intended to be within the scope of the appended claims and their equivalents.

Claims

1. a plurality of light sources disposed on a substrate; one or more wavelength conversion members including quantum dots, arranged facing the plurality of light sources in a thickness direction; a plurality of wall members provided on the substrate so as to surround the light source; and a first region occupied by the one or more wavelength converting members is larger than a second region surrounded by the plurality of wall members; at least a portion of the first wavelength light in a first wavelength range from the plurality of light sources is converted to second wavelength light in a second wavelength range; The plurality of wall members are in indirect contact with the one or more wavelength converting members. Light-emitting device.

2. A plurality of light sources arranged on a substrate; one or more wavelength conversion members including quantum dots, arranged facing the plurality of light sources in a thickness direction; a plurality of wall members provided on the substrate so as to surround the light source; one or more wavelength converting units each including the one or more wavelength converting members and one or more transparent members; and a first region occupied by the one or more wavelength converting members is larger than a second region surrounded by the plurality of wall members; at least a portion of the first wavelength light in a first wavelength range from the plurality of light sources is converted to second wavelength light in a second wavelength range; The upper surface of each of the plurality of wall members is in indirect contact with the rear surface of each of the one or more wavelength converting units. Light-emitting device.

3. the first region overlaps with the entire second region in the thickness direction; 3. The light emitting device according to claim 1.

4. The wavelength conversion element further includes one or more wavelength conversion units each including one or more wavelength conversion members and one or more transparent members. The light emitting device according to claim 1 .

5. The light source further includes a single light diffusing member that commonly covers the plurality of light sources.

3. The light emitting device according to claim 1.

6. The plurality of wall members include inner wall surfaces that reflect the first wavelength light from the light source. The light emitting device according to claim 4.

7. The inner wall surface is inclined so as to be farther away from the light source as it goes from the substrate toward the wavelength conversion unit. The light emitting device according to claim 6.

8. The wall member includes a highly thermally conductive material having a thermal conductivity higher than that of the one or more wavelength converting units. The light emitting device according to claim 4 .

9. The highly thermally conductive material includes at least one of aluminum and copper. The light emitting device according to claim 8.

10. Heat from the one or more wavelength converting members is absorbed by the wall members via the one or more transparent members. The light emitting device according to claim 4 .

11. The one or more transparent members protect the one or more wavelength converting members from moisture. The light emitting device according to claim 3 .

12. The plurality of wall members have a property of reflecting light. The light-emitting device according to claim 1 or 2.

13. A light-reflecting film is vapor-deposited on the wall members. The light-emitting device according to claim 1 or 2.

14. The wall members are provided with a multilayer reflective film. The light-emitting device according to claim 1 or 2.

15. The optical sheet may further be disposed on a surface of the at least one wavelength conversion unit opposite to a surface facing the plurality of light sources. The light emitting device according to claim 2 or 4.

16. The optical sheet is a polarization separation sheet.

16. The light emitting device according to claim 15.

17. The optical sheet is a diffusion sheet.

16. The light emitting device according to claim 15.

Images