Light-emitting device

Abstract

The present invention provides a light-emitting device that can effectively suppress uneven brightness and further improve the contrast ratio between a lit area and a non-lit area. A light-emitting device comprises: a substrate (12) on which a plurality of light sources (11) are arranged; a partition member (13) having a wall portion (13A) surrounding each of the light sources 11 and having a top portion (13a) and an inclined surface (13b), wherein the area surrounded by the wall portion (13A) is regarded as a partition (C), and the partition member (13) has a plurality of partitions (C); and a diffuser (14) arranged above the light source (11), having a first convex portion (14a) surrounding the light source (11) on a surface opposite to the substrate (12) and in an area overlapping with the inclined surface (13b) when viewed from above.

Description

Technical Field

[0001] The present disclosure relates to a light emitting device. Background Art

[0002] As a direct-type backlight used for liquid crystal televisions, etc., a surface light-emitting device is known. For example, as an example of a surface light-emitting device, in a light-emitting device described in Reference Document 1, a plurality of light sources are arranged in a matrix, and above the plurality of light sources, a diffusion plate having a convex portion integrally formed with a curved protrusion is provided. Thus, when the surface light-emitting device is viewed from the display surface side, the occurrence of uneven brightness can be suppressed.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: (Japanese) Patent Publication No. 2012-221779 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, when local dimming is performed on the light source in such a light emitting device, light emitted from the light source in the lit area and scattered and guided by a diffuser or the like sometimes enters the non-lit area adjacent to the lit area, thereby reducing the contrast ratio between the non-lit area and the lit area. In addition, when viewing from the display surface side of the surface light emitting device, it is not possible to fully eliminate uneven brightness, and a countermeasure for obtaining uniform surface light emission is being sought.

[0008] The present disclosure has been made in view of the above-mentioned problems, and provides a light emitting device that can effectively suppress uneven brightness and further improve the contrast ratio between a lit area and a non-lit area.

[0009] Means for solving problems

[0010] This application includes the following inventions.

[0011] A light emitting device, comprising:

[0012] A substrate is configured with a plurality of light sources;

[0013] a partition member having a wall portion surrounding each of the light sources and having a top and an inclined surface, wherein an area surrounded by the wall portion is defined as a partition, and the partition member has a plurality of the partitions; and

[0014] The diffuser plate is disposed above the light source and has a first convex portion surrounding the light source on a surface facing the substrate and in a region overlapping the inclined surface in a plan view.

[0015] Effects of the Invention

[0016] According to the light emitting device of one embodiment of the present invention, it is possible to effectively suppress uneven brightness and further improve the contrast ratio between the lighting area and the non-lighting area. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1A This is a schematic cross-sectional view of a light emitting device according to one embodiment of the present invention.

[0018] Figure 1B yes Figure 1A Schematic top view of the light-emitting device.

[0019] Figure 1C yes Figure 1A A partially enlarged schematic cross-sectional view of the periphery of a light-emitting element of a light-emitting device.

[0020] Figure 1D It is used to illustrate Figure 1A A schematic top view showing the positional relationship between a diffuser plate and a partition member in a partition of a light-emitting device.

[0021] Figure 1E yes Figure 1A An enlarged schematic cross-sectional view of a portion near a partition member of a light-emitting device.

[0022] Figure 2A It is a schematic cross-sectional view of a light emitting device according to another embodiment of the present invention.

[0023] Figure 2B It is a schematic cross-sectional view of a light emitting device according to still another embodiment of the present invention.

[0024] Figure 2C It is used to illustrate Figure 2A And a schematic top view of the positional relationship between the diffuser plate and the partition member in one partition of the 2C light-emitting device.

[0025] Figure 2D yes Figure 2A A partially enlarged schematic cross-sectional view of a diffuser plate in a light-emitting device.

[0026] Figure 3A It is a schematic cross-sectional view of a light emitting device according to still another embodiment of the present invention.

[0027] Figure 3B It is a schematic cross-sectional view of a light emitting device according to still another embodiment of the present invention.

[0028] Figure 4 yes Figure 1A An enlarged schematic cross-sectional view of a portion near other partition components of the light-emitting device.

[0029] Description of symbols

[0030] 11 Light Source

[0031] 12 substrate

[0032] 13 Partition components

[0033] 13a Top

[0034] 13b Wall

[0035] 13b1 Upper inclined surface

[0036] 13b2 Lower inclined surface

[0037] 13c Bottom

[0038] 13d Through hole

[0039] 14, 34, 44 Diffuser Plate

[0040] 14a, 34a, 44a first convex part

[0041] 34b, 44b second convex part

[0042] 15 Light-emitting element

[0043] 18A, 18B conductor wiring

[0044] 19 Joint components

[0045] 20 Light reflective film

[0046] 21 Sealing member

[0047] 21a Bottom Fill

[0048] 22 Wavelength conversion sheet

[0049] 23 First Prism Sheet

[0050] 24 Second prism sheet

[0051] 25 Polarized light sheet

[0052] 26 First reflection part

[0053] 28 Covering components DETAILED DESCRIPTION

[0054] Hereinafter, the embodiments of the present disclosure will be described with reference to the accompanying drawings as appropriate. The embodiments described below embody the technical ideas of the present disclosure, and the present disclosure is not limited to the following unless otherwise specified. In addition, the contents described in one embodiment or example can also be applied to other embodiments or examples. The size, positional relationship, etc. of the components shown in the drawings are sometimes exaggerated to make the description clear.

[0055] In the present embodiment, the light extraction surface of the light source may be referred to as an upper surface, and the light extraction surface side may be referred to as an upper side.

[0056] A light emitting device according to one embodiment of the present invention is Figure 1A As shown in FIG. 1 and B, it comprises a plurality of light sources 11, a substrate 12, a partition member 13, and a diffuser 14. The plurality of light sources 11 are arranged on the substrate 12. The partition member 13 has a wall portion 13A that surrounds each of the light sources 11 and has a top 13a and an inclined surface 13b. The range (that is, area and space) surrounded by the wall portion 13A having the top 13a is defined as a partition C, and the partition member 13 has a plurality of partitions C. The diffuser 14 is arranged above the light source 11, and has a first convex portion 14a that surrounds the light source 11 in a region M that is on a surface opposite to the substrate 12 and overlaps with the inclined surface 13b when viewed from above. The light-emitting device functions as a surface-emitting light-emitting device.

[0057] In this way, by arranging the first convex portion in the area of ​​the diffuser 14 where the light emitted from the light source 11 and reflected by the inclined surface 13b of the partition member 13 is concentrated, that is, the area M overlapping the inclined surface when viewed from above, the concentrated light can be effectively dispersed. Thus, when the light-emitting device is viewed from the light extraction surface side, the brightness unevenness can be effectively suppressed. In addition, by arranging the partition member 13 at an appropriate position, the light emitted from a specific light source 11 can be prevented from intruding into the adjacent area. Thus, the intrusion of light into the adjacent area can be effectively prevented or reduced. As a result, when the adjacent area is a non-lit area, the contrast ratio can be further improved.

[0058] (Light source 11)

[0059] The light source 11 is a member that emits light, and includes, for example, a light emitting element that emits light itself, an element in which a light emitting element is sealed with a light-transmitting resin or the like, a surface-mounted light emitting device (also called an LED) in which a light emitting element is encapsulated, and the like.

[0060] For example, as the light source 11, Figure 1CAs shown, the light emitting element 15 can be covered with a sealing member 21. The light source may be an element using one light emitting element 15, or may be an element using a plurality of light emitting elements as one light source.

[0061] The light source 11 may also be an element having any light distribution characteristics, but in order to emit less uneven brightness in each partition C surrounded by the wall portion 13A of the partition member 13 described later, a wide light distribution is preferably used. In particular, each of the light sources 11 preferably has a batwing light distribution characteristic. This suppresses the amount of light emitted in the direction directly above the light source 11, widens the light distribution of each light source, and irradiates the widened light to the wall portion 13A and the bottom surface 13c, thereby suppressing uneven brightness in each partition C surrounded by the wall portion 13A.

[0062] Here, the batwing light distribution characteristic is defined as a light intensity distribution having a stronger light intensity than 0° at an angle where the absolute value of the light distribution angle is larger than 0°, when the light axis L is set to 0°. Figure 1C As shown, it is defined as a line that passes through the center of the light source 11 and intersects perpendicularly with a line on the plane of the substrate 12 described later.

[0063] In particular, as the light source 11 having the batwing light distribution characteristic, for example, Figure 1C As shown in the figure, an element using a light emitting element 15 having a light reflecting film 20 on the upper surface is used. As a result, light directed upward to the light emitting element 15 is reflected by the light reflecting film 20, and the amount of light directly above the light emitting element 15 is suppressed, so that a bat-wing light distribution characteristic can be obtained. The light reflecting film 20 can be directly formed on the light emitting element 15, so there is no need to combine a special lens for setting a bat-wing light distribution in another way, and the thickness of the light source 11 can be reduced.

[0064] The light reflecting film 20 formed on the upper surface of the light emitting element 15 may also be any one of a metal film such as silver or copper, a dielectric multilayer film (DBR film), or a combination thereof. The light reflecting film 20 preferably has an angle dependence of reflectivity with respect to the incident angle for the emission wavelength of the light emitting element 15. Specifically, the reflectivity of the light reflecting film 20 is preferably set to be lower for oblique incidence than for vertical incidence. As a result, the change in brightness directly above the light emitting element becomes slower, and it is possible to suppress the situation where the light directly above the light emitting element becomes extremely dark, such as a dark spot.

[0065] The light source 11 may be a light emitting element 15 directly mounted on a substrate with a height of 100 to 500 μm. The light reflecting film 20 may be a light emitting element with a thickness of 0.1 to 3.0 μm. Even including the sealing member 21 described later, the thickness of the light source 11 may be about 0.5 to 2.0 mm.

[0066] The plurality of light sources 11 are preferably capable of being driven independently of one another and are mounted on a substrate 12 to be described later so that dimming control (for example, local dimming or HDR) can be performed for each light source.

[0067] (Light emitting element 15)

[0068] As the light emitting element 15, a known element can be used. For example, it is preferable to use a light emitting diode as the light emitting element. As for the light emitting element, an element of any wavelength can be selected. For example, an element using a nitride semiconductor can be used as a blue or green light emitting element. In addition, GaAlAs, AlInGaP, etc. can be used as a red light emitting element. Furthermore, a semiconductor light emitting element made of materials other than these can also be used. The composition of the light emitting element used, as well as the light emitting color, size, number, etc. can be appropriately selected according to the purpose.

[0069] The light emitting element 15 can be exemplified by Figure 1C As shown in the figure, a component is flip-chip mounted via a bonding member 19 in a manner that crosses a pair of positive and negative conductor wirings 18A and 18B set on the upper surface of the substrate 12. Among them, the light-emitting element 15 can not only be flip-chip mounted, but also can be face-up mounted. The bonding member 19 is a member for fixing the light-emitting element 15 to the substrate or the conductor wiring, and insulating resins or conductive members can be listed. In the case where the light-emitting element 15 is flip-chip mounted on the substrate, a conductive member is used. Specifically, Au alloys, Ag alloys, Pd alloys, In alloys, Pb-Pd alloys, Au-Ga alloys, Au-Sn alloys, Sn alloys, Sn-Cu alloys, Sn-Cu-Ag alloys, Au-Ge alloys, Au-Si alloys, Al alloys, Cu-In alloys, mixtures of metals and fluxes, etc. can be listed.

[0070] (Sealing member 21)

[0071] The sealing member 21 covers the light emitting element for the purpose of protecting the light emitting element from the external environment and optically controlling the light output from the light emitting element. The sealing member 21 is formed of a translucent material. As the material, translucent resins such as epoxy resin, silicone resin or resins mixed with them, glass, etc. can be used. Among them, silicone resin is preferably used in consideration of light resistance and ease of forming. The sealing member 21 may also include a wavelength conversion material such as a phosphor that absorbs light from the light emitting element and emits light of a wavelength different from the output light from the light emitting element, a diffusing agent for diffusing the light from the light emitting element, a colorant corresponding to the light color of the light emitting element, etc.

[0072] As the phosphor, the diffusing agent, the coloring agent, and the like, those known in the art can be used.

[0073] The sealing member 21 may be in direct contact with the substrate 12 .

[0074] The sealing member 21 can be adjusted to a viscosity that can be printed, applied by a dispenser, etc., and hardened by heating treatment or light irradiation. The sealing member 21 may be formed into a substantially hemispherical shape, a convex shape that is longitudinally long when viewed in cross section (a shape that is longer in the Z direction than in the X direction when viewed in cross section), a flat convex shape when viewed in cross section (a shape that is longer in the X direction than in the Z direction when viewed in cross section), or a circular or elliptical shape when viewed on the upper surface.

[0075] The sealing member 21 may be disposed as an underfill 21 a between the lower surface of the light emitting element 15 and the upper surface of the substrate 12 .

[0076] (Substrate 12)

[0077] The substrate 12 is a component for mounting a plurality of light sources 11. Figure 1C As shown, on the upper surface thereof, there are conductor wirings 18A and 18B for supplying power to the light source 11 such as the light emitting element 15. A covering member 28 covers the region where no electrical connection is made among the conductor wirings 18A and 18B.

[0078] The material of the substrate 12 can be any material as long as it can insulate and separate at least one pair of conductor wirings 18A and 18B. For example, ceramics, resins, composite materials, etc. can be cited. As ceramics, for example, alumina, mullite, forsterite, glass ceramics, nitrides (for example, AlN), carbides (for example, SiC), LTCC, etc. can be cited. As resins, phenolic resins, epoxy resins, polyimide resins, BT resins, polyphthalamide (PPA), polyethylene terephthalate (PET), etc. can be cited. As composite materials, the above-mentioned resins mixed with glass fibers, SiO 2 、TiO 2 、Al 2 O 3 Materials with inorganic fillers such as glass fiber reinforced resin (glass epoxy resin), metal substrates with insulating layers formed on metal components, etc.

[0079] The thickness of the substrate 12 can be appropriately selected, and the substrate 12 may be a flexible circuit board that can be manufactured in a roll-to-roll manner or a rigid substrate. The rigid substrate may be a thin rigid substrate that can be bent.

[0080] The conductor wirings 18A and 18B may be formed of any material as long as they are conductive members, and materials generally used as wiring layers of circuit boards, etc. may be used. A plating film, a light reflecting film, etc. may be formed on the surface of the conductor wirings.

[0081] The cover member 28 is preferably formed of an insulating material. The material may be the same as the material exemplified as the substrate material. The cover member can prevent light leakage or absorption by using a material containing a white filler or the like in the above-mentioned resin, thereby improving the light extraction efficiency of the light emitting device.

[0082] (Partition component 13)

[0083] Partition component 13 such as Figure 1A , 1B As shown in 1D and the like, there is a wall portion 13A that surrounds each of the light sources 11 and has a top 13a and an inclined surface 13b. The range (region and space) surrounded by the wall portion 13A including the top 13a is set as a partition C, and the partition member 13 is a member having a plurality of partitions C. In addition, the top 13a can be regarded as the boundary of adjacent partitions C when viewed from above.

[0084] The partition member 13 preferably has a bottom surface 13c in the partition C. In other words, the partition member 13 includes the bottom surface 13c and the wall portion 13A to form the partition C. The bottom surface 13c has a through hole 13d disposed substantially in the center of the partition C. Figure 1A As shown in the figure, it is preferred to arrange the light source 11 in the through hole 13d. The shape and size of the through hole 13d may be such that the light source 11 is fully exposed, and it is preferred to set the outer edge of the through hole 13d to be located only near the light source 11. Thus, when the partition member 13 is reflective, the light from the light source can be reflected even on the bottom surface 13c, and the light extraction efficiency can be improved.

[0085] The top 13a is the highest part of the wall 13A, and is preferably formed by at least two walls 13A surrounding the adjacent area. The top 13a may be a plane, but is preferably in the shape of an ridge formed by at least two walls 13A surrounding the adjacent area. Figure 1A As shown in FIG. 1 and FIG. 2 , the longitudinal cross-section of at least two wall portions 13A constituting the top 13a preferably forms an acute triangle, more preferably an acute isosceles triangle. The acute angle of the acute triangle or acute isosceles triangle, i.e., the angle of the top (in Figure 1E α) is preferably set to be greater than 30° and less than 90°, for example. By setting it to such a range, the space and area occupied by the partition member 13 can be reduced, the height of the partition member 13 can be reduced, and the light-emitting device can be miniaturized and thinned.

[0086] The pitch P between the tops 13a of the partition members 13 can be appropriately adjusted according to the size of the light source used, the size and performance of the intended light emitting device, etc. For example, it is 1 mm to 50 mm, preferably 5 mm to 20 mm, and more preferably 6 mm to 15 mm.

[0087] The inclined surface 13b of the wall portion 13A surrounding the light source 11 is preferably formed of a surface inclined so as to widen upward from the bottom surface 13c and the vicinity of the upper surface of the substrate 12. Figure 1E In the embodiment, γ) can be, for example, 45° to 60°. Figure 4 As shown, the inclined surface may also include an upper inclined surface 13b1 (U) and a lower inclined surface 13b2 (L) having different inclination angles in the vertical direction. The angles of these inclined surfaces can be appropriately set within the above range. For example, the angle of the upper inclined surface 13b1 (in Figure 1E The angle equal to γ) may also be smaller than the angle of the lower inclined surface 13b2, but it is preferably as follows Figure 4 As shown, the angle of the upper inclined surface 13b1 is larger than the angle of the lower inclined surface 13b2.

[0088] The height of the partition member 13 itself, that is, the length from the lower surface of the bottom surface 13c of the partition member 13 to the top 13a is 8 mm or less, preferably about 1 mm to 4 mm in the case of a thinner light emitting device, and the distance to the diffuser 14 is set to about 8 mm or less, preferably about 2 mm to 4 mm in the case of a thinner light emitting device. Thus, the backlight unit including the optical components such as the diffuser 14 can be made very thin.

[0089] The thickness of the partition member 13 may be constant or may vary depending on the location, but the partition member 13 constituting the upper inclined surface is preferably thinner than the partition member 13 constituting the lower inclined surface. The thickness of the partition member 13 may be, for example, 100 μm to 300 μm.

[0090] The shape of the partition C formed by the partition member 13 surrounding the light source 11, that is, the shape of the area partitioned by the wall portion 13A, can be, for example, circular, elliptical, etc. in a plan view, but in order to efficiently arrange the multiple light sources, it is preferably a polygon such as a triangle, a quadrilateral, or a hexagon. As a result, it is easy to divide the light-emitting area into an arbitrary number of partitions by the wall portion 13A according to the area of ​​the light-emitting surface of the surface light-emitting device, and the light-emitting area can be arranged with high density. The number of partitions C divided by the wall portion 13A can be set arbitrarily, and the shape and arrangement of the wall portion 13A, the number of partitions C, etc. can be changed according to the desired size of the light-emitting device.

[0091] The partition member 13 can be configured according to the number and position of the light source 11 arranged on the substrate 12, so that when viewed from above, for example, three partitions C are adjacent and the ends of the three tops are concentrated at one point, such as Figure 1B There are various shapes such as a shape in which four sections C are adjacent to each other and four tops are concentrated as shown, a shape in which six sections C are adjacent to each other and six tops are concentrated at one point, etc.

[0092] The partition member 13 is preferably arranged on the substrate 12, and the lower surface of the bottom surface 13c of the partition member 13 and the upper surface of the substrate 12 are preferably fixed. In particular, it is preferred to fix the periphery of the through hole 13d using a light-reflective adhesive member so that the emitted light from the light source 11 does not enter between the substrate 12 and the partition member 13. For example, it is more preferred to arrange the light-reflective adhesive member in a chain along the outer edge of the through hole 13d. The adhesive member may also be a double-sided tape, a hot-melt adhesive sheet, or a resin adhesive such as a thermosetting resin and a thermoplastic resin. These adhesive members preferably have a high flame retardancy. Among them, the partition member 13 may also be fixed to the substrate 12 by screws, etc.

[0093] The partition member 13 is preferably a reflective member. Thus, the light emitted from the light source 11 can be efficiently reflected by the wall portion 13A and the bottom surface 13c. In particular, when the wall portion 13A is inclined as described above, the light emitted from the light source 11 is irradiated to the wall portion 13A, and the light can be reflected upward. Therefore, even when the adjacent partition C is not lit, the contrast ratio can be further improved. In addition, the light can be reflected upward more efficiently.

[0094] The partition member 13 may be formed by using a resin containing a reflective material composed of metal oxide particles such as titanium oxide, aluminum oxide, silicon oxide, etc., or may be formed by using a resin without a reflective material and then providing a reflective material on the surface. Preferably, the reflectivity of the emitted light from the light source 11 is set to be 70% or more.

[0095] The partition member 13 can be formed by molding using a mold, a molding method based on light shaping, etc. As a molding method using a mold, a molding method such as injection molding, push molding, compression molding, vacuum molding, pressure molding, and stamping molding can be applied. For example, by vacuum molding using a reflective sheet formed of PET or the like, a partition member 13 in which the bottom surface 13c and the wall portion 13A are integrally formed can be formed.

[0096] The partition member 13 arranges a plurality of partitions C in a row direction, a column direction or a matrix. Figure 1BAs shown, it is possible to arrange five light sources 11 in the X direction and five in the Y direction, with a total of 25 light sources 11 arranged in a matrix on a substrate, with each light source 11 surrounded by a wall portion 13A, defining 25 partitions C that are roughly square when viewed from the upper surface, and a through hole 13d for placing the light source 11 on the bottom surface 13c approximately in the center of the partition C.

[0097] (Diffuser plate 14)

[0098] The diffuser 14 is a component that diffuses the incident light and allows it to pass through, and preferably, one diffuser 14 is arranged above the plurality of light sources 11. The diffuser 14 has a first convex portion 14a that surrounds the light source 11 on the surface opposite to the substrate 12 and in the region M that overlaps with the inclined surface 13b when viewed from above. As described above, in the case where the inclined surface 13b has an upper inclined surface and a lower inclined surface, it is preferred that the first convex portion is provided in the region that overlaps with the upper inclined surface when viewed from above. In other words, the first convex portion may also be arranged in the central portion of the region M that overlaps with the inclined surface 13b when viewed from above, but is preferably biased toward being close to the top 13a. In the present application specification, encirclement may also mean completely surrounding the light source 11 continuously, or may mean being divided into a plurality of portions to surround the light source 11.

[0099] In the case where the shape of the partition C, i.e., the shape of the area partitioned by the wall portion 13A, is a polygon such as a triangle, a quadrilateral, or a hexagon when viewed from above, it is preferably formed along the shape. Figure 1B As shown, when the wall portion 13A constituting one partition is arranged in a quadrilateral shape so as to surround the light source 11 in a plan view, the first convex portion 14a is arranged in a quadrilateral ring shape in a continuous or divided manner.

[0100] The height (thickness, in mm) of the first convex portion 14a Figure 1E In the example, T) can be set to the thickness of the thinnest part of the diffuser plate constituting one partition (for example, Figure 1E The width of the first convex portion 14a is 5% to 30%, preferably 9% to 20%. Figure 1E The W) in the above-mentioned area M may be 10% to 90%, preferably 20% to 70%, of the width of the area M. For example, in terms of the thickness of the diffuser 14, the thickness t of the thinnest portion in the partition is 0.2 mm to 5 mm, preferably 0.5 mm to 2 mm, the height T of the first protrusion 14a is 0.05 mm to 2 mm, preferably 0.1 mm to 0.6 mm, and the width W of the first protrusion 14a may be 0.1 mm to 1 mm, preferably 0.2 mm to 0.7 mm.

[0101] The first convex portion 14a may also be in various shapes such as a dome, a ridge, a column, a frustum, etc., but preferably has a bilaterally symmetrical cross-sectional shape along the center line of the first convex portion, such as Figure 1E As shown in FIG. 1 , it is more preferable to have a bilaterally symmetrical dome shape.

[0102] The diffuser plate 14 is preferably arranged substantially parallel to the substrate 12. For example, the surface of the light extraction surface side of the diffuser plate 14 may have projections and depressions, but it is more preferable that the surface is flat and substantially parallel to the substrate 12. In the case of projections and depressions, for example, the projections and depressions may be 0.01 mm to 0.1 mm. The projections and depressions may diffuse incident light.

[0103] The diffuser 14 can be made of a material that absorbs little visible light, such as polycarbonate resin, polystyrene resin, acrylic resin, polyethylene resin, etc. The diffuser 14 may be made of materials having different refractive indices dispersed therein to diffuse incident light.

[0104] As the material having different refractive indexes, for example, a material can be selected from polycarbonate resin, acrylic resin, and the like and used.

[0105] The thickness of the diffuser plate 14 and the degree of light diffusion can be appropriately set, and commercially available materials such as a light diffuser sheet and a diffuser film can be used.

[0106] For example, Figures 2A to 2D As shown, in addition to the first protrusions 34a and 44a, the diffuser plates 34 and 44 may also have second protrusions 34b and 44b on the surface opposite to the substrate 12 and in the area overlapping with the light source 11 when viewed from above. The planar shape of the second protrusions 34b and 44b may also be arranged only in the area overlapping with the light source, or in a shape corresponding thereto, and the area overlapping with the light source can be arranged in the center and set to a similar shape corresponding to the area. As the planar shape of the second protrusion, for example, a circular, polygonal or rounded polygonal shape can be listed. In addition, the position of the outer edge of the second protrusion when viewed from above can be set to a position that surrounds the light source with an area of ​​more than 110%, for example, when the area of ​​the area overlapping with the light source is set to 100%. The outer edge of the second protrusion is preferably separated from the first protrusion. Among them, it is preferred that the second protrusions 34b and 44b are arranged in the center of the area overlapping with the light source 11, and have a similar shape corresponding to the area, and have a shape that is closer to the first protrusion as the distance D from the first protrusion increases, such as Figure 2C As shown in FIG. 1 , the outer edge is more preferably circular. For example, the size of the second convex portion when viewed from above can be listed as a diameter (in Figure 2DIn the example, WW) is 10% to 80% of the pitch P, and may be 30% to 70%. Specifically, it may be 0.3 mm to 35 mm, preferably 1.5 mm to 15 mm, and more preferably 1.8 mm to 10 mm. The distance D may be, for example, 0 mm to 4 mm, and preferably 1 mm to 3 mm.

[0107] The second convex portion 34b, 44b is preferably thickest in the area overlapping with the light source, and more preferably thickest just above the center of the light source. For example, various shapes such as bowl, cone, truncated cone, and column are exemplified, but preferably the cone or truncated cone is thickest at the center or approximately the center of the light source. In this case, the surface from the center or approximately the center of the light source toward its periphery may be a curve convex toward the substrate side when viewed in cross section, or may be a shape such as Figure 2A The curve shown is concave toward the light extraction surface (in Figure 2A , 2D , 34b), or Figure 2B The straight line shown (in Figure 2B In addition, the cross-sectional shape of the second protrusion passing through the thickest film is preferably a bilaterally symmetrical shape.

[0108] The thickness of the diffuser plate at the thickest portion of the second protrusions 34b and 44b (in Figure 2D In the example, TT) can be set to the thickness of the thinnest part of the diffuser plate constituting one partition (for example, Figure 1E as well as Figure 2D In the embodiment of FIG. 1 , the thickness TT of the diffuser plate at the thickest portion of the second protrusion 34 is 2 mm to 5 mm, preferably 2 mm to 3.5 mm.

[0109] (Other components)

[0110] The light emitting device of this embodiment may include a reflective member and the like.

[0111] (Reflection component)

[0112] For example, the diffuser 14 may also be on the upper surface, such as Figure 3A As shown, a first reflecting portion 26 is disposed above the light source 11, preferably directly above the light source 11. The first reflecting portion 26 may also be as shown in FIG. Figure 3BAs shown, it is arranged on the surface opposite to the substrate of the diffuser plate 14. In the area above the light source 11, especially in the area directly above, the distance between the diffuser plate 14 and the light source 11 becomes the shortest. Therefore, the brightness in this area becomes higher. The shorter the distance between the diffuser plate 14 and the light source 11, the more significant the brightness unevenness of the area directly above the area where the light source 11 is not configured becomes. Therefore, by arranging the first reflective portion 26 on the surface of the diffuser plate 14, a part of the highly directional light of the light source 11 is reflected and returned to the direction of the light source 11, thereby reducing the brightness unevenness.

[0113] The first reflecting portion 26 can be formed of a material containing a light reflecting material. For example, a resin containing a light reflecting material and / or an organic solvent can be cited. As the light reflecting material, for example, metal oxide particles such as titanium oxide, aluminum oxide, and silicon oxide can be cited. The resin and the organic solvent can be appropriately selected in consideration of the metal oxide particles used, the characteristics required for the manufactured light-emitting device, and the like. Among them, as the resin, it is preferred to use a light-transmitting and light-curing resin with acrylic resin, epoxy resin, etc. as the main component.

[0114] The first reflecting portion 26 may further contain a pigment, a light absorbing material, a fluorescent substance, etc. in the material constituting the first reflecting portion 26 .

[0115] The first reflection part 26 can be formed in various shapes or patterns such as predetermined stripes or islands. The first reflection part 26 can be formed by any method known in the art such as printing, inkjet, or spray.

[0116] The thickness of the first reflection portion may be, for example, 10 μm to 100 μm.

[0117] The light emitting device may also include at least one selected from the group consisting of a wavelength conversion sheet, a prism sheet, and a polarizing sheet for converting light from the light source into light of a different wavelength above the diffusion plate. Figure 3B As shown, optical components such as wavelength conversion sheet 22, prism sheet (first prism sheet 23 and second prism sheet 24), polarizing sheet 25 are directly or indirectly arranged above the diffuser 14 at a predetermined distance or on the upper surface of the diffuser 14, and a liquid crystal panel is further arranged thereon, so that a surface-emitting light-emitting device used as a direct-type backlight light source can be provided. The stacking order of these optical components can be set arbitrarily.

[0118] (Wavelength conversion sheet 22)

[0119] The wavelength conversion sheet 22 may be disposed on either the upper surface or the lower surface of the diffuser 14, but is preferably disposed on the upper surface or the lower surface of the diffuser 14. Figure 3BAs shown, it is arranged on the upper surface. The wavelength conversion sheet 22 absorbs a part of the light emitted from the light source 11, and emits light of a wavelength different from the wavelength of the light emitted from the light source 11. For example, the wavelength conversion sheet 22 can be configured as a light-emitting device that absorbs a part of the blue light from the light source 11 and emits yellow light, green light and / or red light, and emits white light. The wavelength conversion sheet 22 is separated from the light-emitting element of the light source 11, so it is possible to use phosphors with poor resistance to heat or light intensity that are difficult to use near the light-emitting element. Thereby, the performance of the backlight as a light-emitting device can be improved. The wavelength conversion sheet 22 has a sheet shape or a layer shape, and contains the above-mentioned phosphors, etc.

[0120] (First prism sheet 23 and second prism sheet 24)

[0121] The first and second prism sheets 23 and 24 have a shape in which a plurality of prisms extending in a predetermined direction are arranged on their surfaces. For example, when the plane of the sheet is viewed two-dimensionally in the x direction and the y direction at right angles to the x direction, the first prism sheet 23 can have a plurality of prisms extending in the y direction, and the second prism sheet 24 can have a plurality of prisms extending in the x direction. The prism sheet can refract light incident from various directions in the direction toward the display panel opposite to the light-emitting device. As a result, the light emitted from the light-emitting surface of the light-emitting device can be emitted mainly in a direction perpendicular to the upper surface, thereby improving the brightness when the light-emitting device is viewed from the front.

[0122] (Polarizing sheet 25)

[0123] The polarizing sheet 25 can selectively transmit light in a polarization direction consistent with the polarization direction of a polarizing plate arranged on the backlight side of a display panel, such as a liquid crystal display panel, and reflect polarization in a direction perpendicular to the polarization direction toward the first and second prism sheets 23 and 24. A portion of the polarized light returned from the polarizing sheet 25 is reflected again by the first and second prism sheets 23 and 24, the wavelength conversion sheet 22, and the diffusion plate 14. At this time, the polarization direction changes, for example, the polarized light is converted into the polarization direction of the polarizing plate of the liquid crystal display panel, and is incident on the polarizing sheet 25 again and emitted to the display panel. In this way, the polarization direction of the light emitted from the light emitting device can be made consistent, and the light in the polarization direction effective for improving the brightness of the display panel can be efficiently emitted. The polarizing sheet 25, the first and second prism sheets 23 and 24, etc. can use commercially available sheets as optical components for backlight.

[0124] Industrial Availability

[0125] The light emitting device of the present invention can be used in various light emitting devices such as a backlight light source of a display device and a light source of a lighting device.

Claims

1. A light emitting device, wherein: have: A substrate is configured with a plurality of light sources; A partition member having a wall portion surrounding each of the light sources and having a top and an inclined surface, wherein an area surrounded by the wall portion is defined as a partition, and a plurality of the partitions are provided; as well as The diffuser is arranged above the light source, and has a first protrusion that surrounds the light source in a rectangular manner when viewed from above, on a surface opposite to the substrate and in an area that overlaps only with the inclined surface when viewed from above, and has a second protrusion that is circular and has an outer edge that surrounds the light source when viewed from above, in an area that overlaps with the light source when viewed from above.

2. The light emitting device according to claim 1, wherein: The first protrusion has a thickness of 10% to 30% of the thinnest thickness of the diffuser plate.

3. The light emitting device according to claim 1, wherein: The first convex portion has a bilaterally symmetrical cross-sectional shape along a center line of the first convex portion.

4. The light emitting device according to any one of claims 1 to 3, wherein: The one partition is a quadrilateral in a plan view, and the first protrusion is a quadrilateral ring in the one partition in a plan view.

5. The light emitting device according to any one of claims 1 to 3, wherein: The inclined surface includes an upper inclined surface and a lower inclined surface having different inclination angles in the vertical direction, and includes the first convex portion in a region overlapping the upper inclined surface in a plan view.

6. The light emitting device according to any one of claims 1 to 3, wherein: The outer edge of the second convex portion is separated from the first convex portion.

7. The light emitting device according to claim 6, wherein: The second protrusion has a thickness of 400% to 600% of the thinnest thickness of the diffuser plate.

8. The light emitting device according to claim 6, wherein: The second convex portion has the thickest film right above the center of the light source.

9. The light emitting device according to claim 8, wherein: The cross-sectional shape of the second convex portion passing through the thickest film is bilaterally symmetrical.

10. The light emitting device according to any one of claims 1 to 3, wherein: The diffusion plate further includes a wavelength conversion sheet thereon.

11. The light emitting device according to any one of claims 1 to 3, wherein: The maximum thickness of the second protrusion is greater than the maximum thickness of the first protrusion.

12. The light emitting device according to any one of claims 1 to 3, wherein: The thickness of the second convex portion gradually decreases from a position directly above the light source toward the periphery.

13. A light emitting device, wherein: have: A substrate is configured with a plurality of light sources; A partition member, comprising a wall portion surrounding each of the light sources and having a top and an inclined surface, wherein an area surrounded by the wall portion is regarded as a partition, and a plurality of the partitions are provided; as well as A diffuser plate is arranged above the multiple light sources, and has multiple first protrusions arranged on the first surface of the diffuser plate facing the substrate, each of the first protrusions is arranged only in an area overlapping with each of the inclined surfaces of the wall portion when viewed from above, each of the first protrusions surrounds each of the multiple light sources in a quadrilateral manner when viewed from above, and has a circular second protrusion whose outer edge surrounds the light source when viewed from above in the area overlapping with the light source when viewed from above.

14. The light emitting device according to claim 13, wherein: The first surface of the diffuser plate has a flat surface surrounding each of the first protrusions.

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