JP7425952B2 - Planar light source - Google Patents

Description

Embodiments of the present invention relate to a planar light source.

2. Description of the Related Art Light emitting modules, which are a combination of light emitting elements such as LEDs (Light Emitting Diodes) and light guide plates, are widely used as planar light sources such as backlights for liquid crystal displays, for example. Further, a planar light source in which a plurality of light guide plates are arranged adjacent to each other has been proposed. When a plurality of light guide plates are arranged with gaps between them, the presence of gaps between the light guide plates can lead to the generation of dark areas and cause uneven brightness on the light emitting surface.

Japanese Patent Application Publication No. 2012-234830 Japanese Patent Application Publication No. 2016-110727

Embodiments of the present invention aim to provide a planar light source that can reduce uneven brightness.

According to one aspect of the present invention, the planar light source includes a substrate, a first surface disposed on the substrate, a first surface located on the substrate side, and a second surface opposite to the first surface. a plurality of light guide plates, a light source disposed on the first surface side of each of the light guide plates, and a first light reflective member. The plurality of light guide plates include a first light guide plate and a second light guide plate that are adjacent to each other. The first light guide plate has a first side surface and a first end protruding from the first side surface. The second light guide plate includes a second side surface facing the first end portion across a first gap, and a second side surface that protrudes from the second side surface and overlaps the first end portion in the thickness direction of the light guide plate. It has two ends. The first light reflective member is disposed below the first side surface and below the second end, and the first light reflective member disposed below the first side surface and the first light reflective member are disposed below the first side surface and below the second end. There is a gap between the first light reflective member and the first light reflective member disposed below the two ends. Each of the first light reflective member disposed below the first side surface and the first light reflective member disposed below the second end portion has a first slope. The first inclined surface has a portion facing a side surface of the light source and another portion located above the top surface of the light source. The first end and the first side surface are continuous via a first curved surface, and the second end and the second side surface are continuous via a second curved surface.

According to the embodiments of the present invention, it is possible to provide a planar light source that can reduce uneven brightness.

FIG. 1 is a schematic plan view of a planar light source according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view taken along line II-II shown in FIG. 1. FIG. FIG. 2 is a schematic enlarged cross-sectional view showing an example of a light source arrangement part in a planar light source according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing a light source in a planar light source according to an embodiment of the present invention. It is a schematic enlarged sectional view which shows another example of the arrangement|positioning part of the light source in the planar light source of embodiment of this invention. FIG. 7 is a schematic enlarged sectional view showing another example of a portion where two light guide plates are adjacent to each other in a planar light source according to an embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings. In each drawing, the same components are designated by the same reference numerals. Note that the dimensions, shapes, etc. of the components shown in the drawings may be exaggerated for ease of understanding, and may not reflect the actual dimensions, shapes, and size relationships between the components. Further, in order to avoid overly complicating the drawings, illustration of some elements may be omitted or an end view showing only a cut surface may be used as a sectional view.

FIG. 1 is a schematic plan view of a planar light source 100 according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view taken along the line II-II shown in FIG.

The planar light source 100 of this embodiment includes a substrate 50 and a plurality of light emitting segments 1a and 1b arranged on the substrate 50. The substrate 50 has a first surface 50a and a second surface 50b opposite to the first surface 50a. A plurality of light emitting segments 1a, 1b are arranged on the first surface 50a of the substrate 50. In FIG. 1, two directions perpendicular to each other within a plane parallel to the first surface 50a of the substrate 50 are referred to as an X direction and a Y direction. For example, the plurality of light emitting segments 1a and 1b are arranged next to each other in the X direction.

Each light emitting segment 1a, 1b has a light guide plate. The light emitting segment 1a has a first light guide plate 10a, and the light emitting segment 1b has a second light guide plate 10b. The first light guide plate 10a and the second light guide plate 10b are adjacent to each other in the X direction on the substrate 50 with a gap 90 in between.

The structure of the end of the first light guide plate 10a adjacent to the second light guide plate 10b is different from the structure of the end of the second light guide plate 10b adjacent to the first light guide plate 10a. Except for these adjacent ends, the first light guide plate 10a and the second light guide plate 10b have the same structure.

Each of the light emitting segments 1a, 1b has a light source 20. Although FIGS. 1 and 2 show an example in which each of the light-emitting segments 1a and 1b includes a plurality of light sources 20, each of the light-emitting segments 1a and 1b may include a single light source 20.

The light emitted by the light source 20 enters the light guide plates 10a, 10b and is guided within the light guide plates 10a, 10b. The light guide plates 10a and 10b are transparent to the light emitted by the light source 20. The light guide plates 10a, 10b have a first surface 12 located on the substrate 50 side, and a second surface 11 located on the opposite side of the first surface 12 and serving as the light emitting surface of the light emitting segments 1a, 1b.

A recess 15 is formed in a portion of the light guide plates 10a, 10b facing the light source 20 on the second surface 11 side. Examples of the recess 15 include recesses in the shape of a polygonal pyramid such as a cone, square pyramid, and hexagonal pyramid, and recesses in the shape of a truncated polygonal pyramid such as a truncated cone, a truncated quadrangular pyramid, and a truncated hexagonal pyramid. It will be done.

A first side surface 61 and a first end portion 62 are arranged in a portion of the first light guide plate 10a adjacent to the second light guide plate 10b. The first end portion 62 protrudes from the first side surface 61 toward the second light guide plate 10b. The upper surface of the first end portion 62 is flush with and continuous with the second surface 11 of the first light guide plate 10a.

A second side surface 71 and a second end portion 72 are arranged in a portion of the second light guide plate 10b adjacent to the first light guide plate 10a. The second end portion 72 protrudes from the second side surface 71 toward the first light guide plate 10a.

A light reflective member 41 is arranged on the first surface 12 of the light guide plates 10a and 10b. A light reflective member 42 is arranged below the first side surface 61 of the first light guide plate 10a and below the second end portion 72 of the second light guide plate 10b.

A light reflective member 43 is arranged between the plurality of light sources 20. The light reflective member 43 is disposed in a recess or groove formed on the second surface 12 side of the light guide plates 10a, 10b, and is in contact with the side surface of the recess or groove. The side surfaces of the recess or groove are, for example, inclined with respect to the second surface 11 or the first surface 12. The side surfaces of the recess or groove may be straight or curved in cross-sectional view. The side surface of the recess or groove can be a curved surface that is convex inward in cross-sectional view, or can be a curved surface that is concave inward. Further, the side surface of the recess or groove may include two or more curved surfaces having different curvatures in cross-sectional view.

The light guide plates 10a, 10b have a third side surface 18 that is not adjacent to other light guide plates. Furthermore, the light guide plates 10a and 10b have an inclined surface 14 formed between the third side surface 18 and the first surface 12. The inclined surface 14 is inclined with respect to the second surface 11 and the first surface 12. The inclined surface 14 and the first surface 12 are continuous, forming an obtuse angle, for example. The inclined surface 14 may be a straight line or a curved line when viewed in cross section. The inclined surface 14 can be a curved surface that is convex inward in cross-sectional view, or can be a curved surface that is concave inward. Further, the inclined surface 14 may include two or more curved surfaces having different curvatures in cross-sectional view. A light reflective member 45 is arranged on such an inclined surface 14.

The light reflective members 41, 42, 43, and 45 can be integrally formed of the same material. The light reflective members 41, 42, 43, and 45 are made of, for example, a resin material containing a light diffusing material. The light reflective members 41, 42, 43, and 45 are, for example, silicone resin or epoxy resin containing particles of titanium oxide, silica, alumina, zinc oxide, or glass as a light diffusing material.

The light emitting segment 1a having the first light guide plate 10a and the light emitting segment 1b having the second light guide plate 10b are adjacent to each other with a gap 90 in between. When arranging a plurality of light emitting segments 1a, 1b on the same substrate 50, by forming a gap 90 between the light emitting segments 1a, 1b, dimensional tolerances of the light guide plates 10a, 10b and the light reflective member 42 can be absorbed. I can do it.

Further, the gap 90 between the light emitting segments 1a and 1b allows the light guide plates 10a and 10b to expand and contract due to the influence of temperature and humidity, so that one of the light guide plates 10a (or 10b) among the adjacent light guide plates 10a and 10b It is possible to prevent the light guide plates 10a, 10b from being deformed or damaged due to pressing the other light guide plate 10b (or 10a).

The gap 90 is between the first end 62 of the first light guide plate 10a and the second side surface 71 of the second light guide plate 10b, and between the first end 62 of the first light guide plate 10a and the second side surface 71 of the second light guide plate 10b. between the first side surface 61 of the first light guide plate 10a and the second end portion 72 of the second light guide plate 10b, and between the light reflective member 42 and the second end below the first side surface 61. It is formed continuously between the portion 72 and the light reflective member 42 below.

The gap 90 includes a first portion 90a extending along the thickness direction of the light guide plates 10a, 10b above the second end 72, and a first portion 90a extending along the thickness direction of the light guide plates 10a, 10b below the first end 62. It has a second portion 90b that extends, and a third portion 90c that laterally connects the first portion 90a and the second portion 90b, and is bent. The first portion 90a and the second portion 90b do not overlap in the thickness direction of the light guide plates 10a and 10b.

The first end 62 of the first light guide plate 10a faces the second side surface 71 of the second light guide plate 10b with a gap 90 in between. The first side surface 61 of the first light guide plate 10a faces the second end 72 of the second light guide plate 10b with a gap 90 in between. The first end 62 of the first light guide plate 10a overlaps the second end 72 of the second light guide plate 10b with a gap 90 in between in the thickness direction of the light guide plates 10a and 10b. The first end 62 of the first light guide plate 10a is located above the second end 72 of the second light guide plate 10b in the thickness direction of the light guide plates 10a, 10b.

According to this embodiment, the first end 62 of the first light guide plate 10a and the second end 72 of the second light guide plate 10b overlap in the thickness direction of the light guide plates 10a and 10b, so that the light emitting surface ( In the second surface 11), it is possible to suppress a decrease in brightness in the area above the gap 90, and to reduce uneven brightness over the entire light emitting surface.

In a plan view of the light emitting surface (second surface 11) of the planar light source 100, the substrate 50, which is a non-light emitting portion (dark portion), cannot be seen through the gap 90. The substrate 50 is covered by the first end 62 of the first light guide plate 10a. The second end portion 72 of the second light guide plate 10b and the light reflective member 42 are located deep inside the opening on the second surface 11 side of the gap 90, so that the opening on the second surface 11 side of the gap 90 does not become dark.

Further, the light reflecting member 42 disposed below the first end 62 and the second end 72 reflects light upward in the area where the gap 90 is formed, so that the brightness of the area where the gap 90 is formed is increased. The decline can be suppressed.

Further, the light reflective member 43 disposed between the adjacent light sources 20 can suppress a decrease in brightness in the area between the adjacent light sources 20 and reduce uneven brightness over the entire light emitting surface.

Further, according to the present embodiment, the light source 20 is held not on the substrate 50 but on the light guide plates 10a, 10b, and the light guide plates 10a, 10b and the light source 20 are integrally configured. The light source 20 can be arranged with high positional accuracy. This also makes it possible to suppress unevenness in the luminance distribution within the light emitting surfaces of the light guide plates 10a and 10b.

A more specific configuration of the planar light source 100 will be described below.

FIG. 3 is a schematic enlarged cross-sectional view showing an example of the arrangement portion of the light source 20 in the planar light source 100. FIG. 4 is a schematic enlarged sectional view of the light source 20.

The light source 20 includes a light emitting element 21 and a translucent member 22. The translucent member 22 can include, for example, a fluorescent substance. The transmittance of the light guide plates 10a and 10b for the light emitted by the light source 20 is preferably 80% or more, and more preferably 90% or more, for example. In this specification, the light emitted by the light source 20 includes the light emitted by the light emitting element 21 and the light emitted by the phosphor included in the translucent member 22. When the light source 20 does not contain a phosphor, the light emitted by the light source 20 is the light emitted by the light emitting element 21.

As the material of the light guide plates 10a and 10b, for example, thermoplastic resin such as acrylic, polycarbonate, cyclic polyolefin, polyethylene terephthalate or polyester, thermosetting resin such as epoxy or silicone, or glass can be used.

The thickness of the light guide plates 10a and 10b is preferably, for example, 200 μm or more and 800 μm or less. The light guide plates 10a and 10b may be composed of a single layer or a laminate of a plurality of layers in the thickness direction.

In the example shown in FIG. 3, the light guide plates 10a and 10b have a recess 13 that opens on the first surface 12 side. A portion of the light source 20 is disposed within the recess 13 in a cross-sectional view.

As shown in FIG. 4, the light emitting element 21 includes a semiconductor stack 25 and a pair of positive and negative electrodes 23. The light emitting element 21 includes, for example, In _x Al _y Ga _1-x-y N (0≦x, 0≦y, x+y≦1) as the semiconductor stack 25, and can emit visible light or ultraviolet light. can. The light emitting element 21 is capable of emitting visible light ranging from blue to red. Further, as the plurality of light emitting elements 21 included in the planar light source 100, light emitting elements 21 that emit light of different colors may be used.

A light-transmitting member 22 is arranged on the main light-emitting surface 21a of the light-emitting element 21. The light emitting element 21 is bonded to a light-transmitting member 22 using a light-transmitting adhesive member 24 such as silicone resin. The light-transmitting adhesive member 24 may include a light-diffusing material made of particles of titanium oxide, silica, alumina, zinc oxide, glass, or a resin having a refractive index different from that of the base material of the light-transmitting adhesive member 24, for example. can be included. The translucent member 22 covers the main light emitting surface 21 a of the light emitting element 21 and extends to an area outside the side surface 21 b of the light emitting element 21 .

As the material of the translucent member 22, for example, silicone resin, epoxy resin, glass, etc. can be used. The light-transmitting member 22 uses these light-transmitting materials as a base material, and may contain a phosphor in the base material. The phosphor is excited by the light emitted by the light emitting element 21 and emits light of a wavelength different from the wavelength of the light emitted by the light emitting element 21. For example, as a phosphor, a yttrium-aluminum-garnet-based phosphor (e.g., Y ₃ (Al, Ga) ₅ O ₁₂ :Ce), a lutetium-aluminum-garnet-based phosphor (e.g., Lu ₃ (Al, Ga) ₅ O ₁₂ :Ce), terbium-aluminum-garnet phosphor (e.g., Tb ₃ (Al, Ga) ₅ O ₁₂ :Ce), β-sialon phosphor (e.g., (Si, Al) ₃ (O, N) ₄ :Eu), α-sialon phosphor (for example, Mz(Si,Al) ₁₂ (O,N) ₁₆ (0<z≦2, and M is Li, Mg, Ca, Y, and La and Ce). lanthanide elements)), nitride-based phosphors such as CASN-based phosphors (e.g., CaAlSiN ₃ :Eu) or SCASN-based phosphors (e.g., (Sr,Ca)AlSiN ₃ :Eu), KSF-based phosphors (e.g. , K ₂ SiF ₆ :Mn) or MGF-based phosphor (for example, 3.5MgO.0.5MgF ₂ .GeO ₂ :Mn), or a quantum dot phosphor can be used. . The translucent member 22 may contain multiple types of phosphors. Further, the light-transmitting member 22 may be formed by laminating a plurality of layers containing different phosphors.

The electrode 23 is arranged on the opposite side of the main light emitting surface 21a of the light emitting element 21. The side surface 21b of the light emitting element 21 is covered with a light reflective member 26. The light reflective member 26 is also arranged on the lower surface of the semiconductor stack 25 so that the surface of the electrode 23 (lower surface in FIG. 4) is exposed. The light reflective member 26 is made of, for example, a resin material containing a light diffusing material. Specifically, the light reflective member 26 is silicone resin or epoxy resin containing a light diffusing material made of particles of titanium oxide, silica, alumina, zinc oxide, glass, or the like. The light reflective member 26 can have a reflectance of 70% or more for light from the light emitting element 21.

As shown in FIG. 3, the light emitting element 21 is located closer to the first surface 12 than the transparent member 22 is. Further, the light-transmitting member 22 is located closer to the second surface 11 than the light emitting element 21 is.

A light-transmitting member 31 is provided between the side surface 13a of the recess 13 where the light source 20 is placed and the side surface of the light source 20 (in this embodiment, the side surface of the light-transmitting member 22 and the side surface of the light-reflecting member 26). It is located. The light source 20 is fixed to the light guide plates 10a and 10b by the light transmitting member 31.

The light-transmitting member 31 is transparent to the light emitted by the light source 20, and is made of, for example, the same resin as the material of the light guide plates 10a, 10b, or a resin with a small difference in refractive index from the material of the light guide plates 10a, 10b. be able to.

It is preferable that there is no space such as an air layer between the side surface of the light source 20 and the light transmitting member 31 and between the side surface 13a of the recess 13 and the light transmitting member 31. Since there is no air layer between the side surface of the light-transmitting member 22 of the light source 20 and the light guide plates 10a, 10b, the difference in refractive index between the light-transmitting member 22 and the light guide plates 10a, 10b is reduced by the air layer. can be made smaller than when there is an intervening member, and light can be easily guided from the light-transmitting member 22 into the light guide plates 10a and 10b.

By arranging a material having a different refractive index from the light guide plates 10a, 10b inside the recesses 15 formed on the second surface 11 side of the light guide plates 10a, 10b, the light irradiated onto the interface with the side surfaces of the recesses 15 is A part of the light can be reflected to the side of the light source 20. A light reflective member 44 is disposed inside the recess 15 in this embodiment. The light reflective member 44 can diffusely reflect a part of the light emitted directly above the light source 20 and transmit the other part. Moreover, the light reflective member 44 can be arranged so as to cover part or all of the side surface of the recess 15. Further, the side surface of the recess 15 may be a straight line or a curved line when viewed in cross section. The side surface of the recess 15 can be a curved surface that is convex inward in cross-sectional view, or can be a curved surface that is concave inward. Further, the side surface of the recess 15 may include two or more curved surfaces having different curvatures in cross-sectional view.

It is preferable that the recessed part 15 is arranged at a position overlapping with the recessed part 13 on the first surface 12 side where the light source 20 is arranged in a plan view. It is preferable that the center of the recess 15 and the center of the recess 13 coincide in plan view. Note that in this specification, a plan view refers to a plan view viewed from the second surface 11 side, which is the light emitting surface of the light emitting segments 1a and 1b.

The light-reflecting member 41 in this embodiment is arranged below the light-transmitting member 31 and is not arranged on the side surface of the light-transmitting member 22 containing the phosphor. A side surface of the light-transmitting member 22 is covered with a light-transmitting member 31.

Wiring 51 is arranged on the lower surface of light reflective member 41 . The wiring 51 is connected to the electrode 23 of the light emitting element 21. The wiring 51 is separated between the pair of electrodes 23.

A substrate 50 is bonded to the wiring 51. The board 50 is, for example, a flexible wiring board. The substrate 50 includes at least an insulating base material 52 and a wiring layer 53. An insulating base material 52 is arranged between the wiring 51 and the wiring layer 53.

The wiring 51 and the wiring layer 53 are connected, for example, via a conductive member that penetrates the insulating base material 52. An insulating film 55 is arranged on the surface of the wiring layer 53. In order to improve the insulation between the electrodes 23 of the light source 20, an insulating film 32 is disposed on the surface of the light reflective member 26 located between the electrodes 23.

The light reflective member 44 disposed in the concave portion 15 facing the light source 20 allows the light emitted upward from the light source 20 to pass therethrough appropriately, while diffusing it downward and in the lateral direction. That is, the light reflective member 44 has an extremely high brightness in the area directly above the light emitting device 20 on the light emitting surfaces (second surfaces 11) of the light emitting segments 1a and 1b compared to the brightness in the area not directly above the light source 20. You can prevent it from happening.

The light emitted from the light source 20 toward the first surface 12 is reflected upward by the light reflective member 41, and the brightness of the light extracted from the second surface 11, which is a light emitting surface, can be improved.

The light reflective member 26 disposed on the side surface of the light emitting element 21 suppresses light that enters the light guide plates 10a and 10b from the light emitting element 21 without passing through the light transmitting member 22 containing fluorescent material.

The light reflective member 41 and the light reflective member 26 can suppress exposure of the insulating base material 52 of the substrate 50 near the light source 20 to the light of the light emitting element 21, and can prevent deterioration of the insulating base material 52. .

In the area between the light reflective member 41 on the first surface 12 and the second surface 11, reflection on the light reflective member 41 and total reflection on the second surface 11 are repeated, and the light source 2 The light from the light guide plates 10a, 10b is guided within the light guide plates 10a, 10b toward the ends of the light guide plates 10a, 10b. A part of the light directed toward the second surface 11 is extracted from the second surface 11 to the outside of the light guide plates 10a and 10b.

The light guided to the inclined surface 14 shown in FIG. 2 of the light guide plates 10a, 10b is reflected toward the second surface 11 by the light reflective member 45 disposed on the inclined surface 14, and It is possible to improve the brightness of the light extracted from the second surface 11 at the end of the surface.

FIG. 5 is a schematic enlarged sectional view showing another example of the arrangement portion of the light source 20 in the planar light source according to the embodiment of the present invention.

The light guide plates 10a and 10b shown in FIG. 5 have a through hole 113 that penetrates from the recess 15 on the second surface 11 side to the first surface 12. The through hole 113 is continuous with the recess 15. The recess 15 and the through hole 113 penetrate from the second surface 11 to the first surface 12. The light source 20 is arranged in the through hole 113.

A light-transmitting member 131 is disposed between the side surface 113a of the through-hole 113 and the side surface of the light source 20 (in this embodiment, the side surface of the light-transmitting member 22 and the side surface of the light-reflecting member 26). There is. The light source 20 is fixed to the light guide plates 10a and 10b by this light transmitting member 131.

The light transmitting member 131 is transparent to the light emitted by the light source 20, and is made of, for example, the same resin as the material of the light guide plates 10a, 10b, or a resin having a small difference in refractive index from the material of the light guide plates 10a, 10b. be able to.

There is no space such as an air layer between the side surface of the light source 20 and the light transmitting member 131 and between the side surface 113a of the penetrating portion 113 and the light transmitting member 131. Since there is no air layer between the side surface of the transparent member 22 of the light source 20 and the light guide plates 10a, 10b, the air layer compensates for the difference in refractive index between the transparent member 22 and the light guide plates 10a, 10b. It can be made smaller than in the case where the light guide plates 10a and 10b are taken from the light transmitting member 22, and the efficiency of taking in light from the light transmitting member 22 to the light guide plates 10a and 10b can be improved.

A light reflective member 46 is disposed on the upper surface of the light transmitting member 22, which is the upper surface of the light source 20. The light-transmitting member 131 is also arranged between the light-reflecting member 46 and the light-reflecting member 44 so as to cover the light-reflecting member 46 .

A light reflective member 41 is arranged on the first surface 12 of the light guide plates 10a and 10b. The light-reflecting member 41 is also arranged below the light-transmitting member 131 and on the side of the light-reflecting member 26 of the light source 20, and is not arranged on the side of the light-transmitting member 22 containing the phosphor. A side surface of the light-transmitting member 22 is covered with a light-transmitting member 131.

The light reflective member 44 and the light reflective member 46 transmit the light emitted upward from the light source 20 appropriately, and diffuse it downward and in the lateral direction. That is, the light reflective member 44 and the light reflective member 46 have extremely high brightness in the area directly above the light source 20 on the light emitting surface (second surface 11) compared to the brightness in the area not directly above the light source 20. can be suppressed.

FIG. 6 is a schematic enlarged sectional view showing another example of a portion where two light guide plates (a first light guide plate 10a and a second light guide plate 10b) are adjacent to each other in a planar light source according to an embodiment of the present invention.

The first end 62 and the first side surface 61 of the first light guide plate 10a are continuous with each other via the first curved surface 63. The second end 72 and the second side surface 71 of the second light guide plate 10b are continuous with each other via the second curved surface 73.

By forming a curved surface between the first end 62 and the first side surface 61, light can be easily guided from inside the first light guide plate 10a to the first end 62. By forming a curved surface between the second end 72 and the second side surface 71, light can be easily guided from inside the second light guide plate 10b to the second end 72. Furthermore, by appropriately setting the curvature of the first curved surface 63 and the curvature of the second curved surface 73, it is possible to reduce the difference in brightness between regions on both sides of the gap 90, which are located on both sides of the gap 90.

Although FIGS. 1 and 2 show a configuration in which two light emitting segments 1a and 1b are arranged side by side, a planar light source may be constructed by arranging three or more light emitting segments next to each other with a gap in between. In that case as well, the end portions of one light guide plate and the end portions of the other light guide plate of adjacent light emitting segments overlap in the thickness direction of the light guide plate, as described above, and a decrease in brightness in the gap is suppressed.

The configuration of the light source 20 is not limited to the configuration shown in FIG. 4. The translucent member 22 containing phosphor may be arranged to cover the side surface of the light emitting element 21. The light-transmitting member 22 does not need to contain phosphor. A member having a light-transmitting property and a light-reflecting property may be placed on the light-transmitting member 22. The light source 20 may be configured from the light-emitting element 21 that does not include the light-transmitting member 22 and the light-reflecting member 26. In such a light source 20, a member having translucency and light reflection properties may be arranged on the light emitting element 21.

A first inclined surface inclined with respect to the second surface 11 or the first surface 12 is formed at an end portion of the first light guide plate 10a adjacent to the second light guide plate 10b, and the first light guide plate 10a of the second light guide plate 10b is A second inclined surface inclined with respect to the second surface 11 or the first surface 12 may be formed at the end adjacent to the second inclined surface, and the first inclined surface and the second inclined surface may be opposed to each other with a gap in between. In particular, it is preferable that the first inclined surface and the second inclined surface face each other in parallel. Even in such a configuration, the first inclined surface of the first light guide plate 10a and the second inclined surface of the second light guide plate 10b overlap in the thickness direction of the light guide plates 10a and 10b, so that the light emitting surface (second In a plan view looking at the surface 11), the substrate 50, which is a non-light emitting part (dark part), cannot be seen through the gap between the adjacent light guide plates 10a and 10b. Thereby, it is possible to suppress a decrease in brightness in the area above the gap between the adjacent light guide plates 10a and 10b, and to reduce uneven brightness over the entire light emitting surface.

The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. All forms that can be implemented by appropriately modifying the design based on the above-described embodiments of the present invention by those skilled in the art also belong to the scope of the present invention as long as they encompass the gist of the present invention. In addition, it is understood that various changes and modifications can be made by those skilled in the art within the scope of the idea of the present invention, and these changes and modifications also fall within the scope of the present invention. .

1a, 1b... Light emitting segment, 10a, 10b... Light guide plate, 11... Second surface, 12... First surface, 14... Inclined surface, 18... Third side surface, 20... Light source, 50... Substrate, 61... First side surface , 62... First end, 63... First curved surface, 71... Second side surface, 72... Second end, 73... Second curved surface, 90... Gap, 100... Planar light source

Claims (6)

A substrate and
a plurality of light guide plates arranged on the substrate, each having a first surface located on the substrate side and a second surface opposite to the first surface;
a light source disposed on the first surface side of each of the light guide plates;
a first light reflective member;
Equipped with
The plurality of light guide plates include a first light guide plate and a second light guide plate that are adjacent to each other,
The first light guide plate has a first side surface and a first end protruding from the first side surface,
The second light guide plate includes a second side surface facing the first end portion across a first gap, and a second side surface that protrudes from the second side surface and overlaps the first end portion in the thickness direction of the light guide plate. having two ends;
The first light reflective member is disposed below the first side surface and below the second end,
There is a gap between the first light reflective member disposed below the first side surface and the first light reflective member disposed below the second end,
Each of the first light reflective member disposed below the first side surface and the first light reflective member disposed below the second end portion has a first slope,
The first inclined surface has a part facing the side surface of the light source and another part located above the position of the top surface of the light source,
The first end portion and the first side surface are continuous via a first curved surface,
A planar light source in which the second end portion and the second side surface are continuous via a second curved surface. The planar light source according to claim 1, wherein the second end of the second light guide plate faces the first side surface of the first light guide plate with a second gap in between. The planar light source according to claim 1 or 2, wherein the second end of the second light guide plate overlaps the first end of the first light guide plate with a third gap in between. A plurality of the light sources are arranged on at least one of the first light guide plate and the second light guide plate,
The planar light source according to claim 1, further comprising a second light reflective member disposed between the plurality of light sources. At least one of the first light guide plate and the second light guide plate has a third side surface that is not adjacent to another light guide plate, and a second inclined surface formed between the third side surface and the first surface. A planar light source according to any one of claims 1 to 4. The planar light source according to claim 5 , further comprising a third light reflective member disposed on the second inclined surface.

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