JP6924958B1 - Planar light source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planar light source in which uneven brightness in a light emitting region is suppressed. A planar light source 100 includes a light source 130, a light source arrangement portion 121 in which a light source is arranged, and a light guide member 120 including a partition defining portion 123 including a groove 122 surrounding the light source arrangement portion. A light-reflecting partition member 140, which is arranged in the partition defining portion, is provided, and in a plan view, the transmission rate of the first portion 124 farthest from the center of the light source C in the partition defining portion is the center of the light source in the partition defining portion. Higher than the transmission of the second portion 125 closest to. [Selection diagram] Fig. 2

Description

The embodiment relates to a planar light source.

A planar light source that combines a light source and a light guide plate is widely used, for example, as a backlight for a liquid crystal display. Patent Document 1 discloses that a groove is provided in the light guide plate and a reflection member is provided in the groove in order to partition the light emitting region for each light source.

U.S. Pat. No. 7,997771

Therefore, an object of the present embodiment is to provide a planar light source in which uneven brightness in a light emitting region is suppressed.

The planar light source according to the embodiment includes a light guide member having a light source, a light source arranging portion in which the light source is arranged, and a partition defining portion including a groove surrounding the light source arranging portion, and the partition defining portion. The first portion of the compartmentalized portion, which is the farthest from the center of the light source, has the highest transmission rate from the center of the light source in the compartmentalized portion. Higher than the transmittance of the second part near.

The planar light source according to the embodiment includes a light source and an outer peripheral portion that surrounds the light source and has a light-reflecting partition member. The light source is covered with a light guide member, and the outer periphery thereof is viewed in a plan view. The transmittance of the first portion of the portion farthest from the center of the light source is higher than the transmittance of the second portion of the outer peripheral portion closest to the center of the light source.

According to this embodiment, it is possible to realize a planar light source in which uneven brightness in the light emitting region is suppressed.

It is a perspective view which shows the planar light source which concerns on 1st Embodiment. It is an enlarged plan view of the planar light source which concerns on 1st Embodiment. It is a figure which shows an example of one of the cross sections in line 3-3 of FIG. It is a figure which shows another example of the cross section in line 3-3 of FIG. It is a figure which shows one example of the cross section in line 4-4 of FIG. It is a figure which shows another example of the cross section in line 4-4 of FIG. FIG. 2 is a cross-sectional view taken along the line 4-4 of FIG. 2, which is a cross-sectional view showing an example of light emitted from a light source. FIG. 3 is a cross-sectional view taken along the line 3-3 of FIG. 2, which is a cross-sectional view showing an example of light emitted from a light source. It is a top view which shows the planar light source which concerns on 1st modification of 1st Embodiment. It is a top view which shows the planar light source which concerns on the 2nd modification of 1st Embodiment. It is a top view which shows the planar light source which concerns on 2nd Embodiment. It is a top view which shows the planar light source which concerns on 3rd Embodiment. It is a top view which shows the part of FIG. 10 enlarged. It is sectional drawing in line 12-12 of FIG. FIG. 3 is a cross-sectional view taken along the line 13-13 of FIG. 11 is a cross-sectional view taken along the line 14-14 of FIG. It is a top view which shows the planar light source which concerns on 4th Embodiment. FIG. 5 is a cross-sectional view taken along the line 16-16 of FIG. It is a top view which shows the planar light source which concerns on the modification of 4th Embodiment. FIG. 6 is a cross-sectional view taken along the line 18A-18A of FIG. 16 is a cross-sectional view taken along the line 18B-18B of FIG.

Hereinafter, for convenience of explanation, the XYZ Cartesian coordinate system is adopted in the present specification. For example, as shown in FIG. 1, the direction from the wiring board 110 toward the light guide member 120 is referred to as "Z direction". Further, the Z direction is also referred to as "upward". Further, the direction opposite to the Z direction is also referred to as "downward". One direction orthogonal to the Z direction is called the "X direction". Further, the direction orthogonal to the Z direction and the X direction is referred to as the "Y direction".

<First Embodiment>
First, the planar light source 100 according to the first embodiment will be described.
FIG. 1 is a perspective view showing a planar light source according to the present embodiment.
FIG. 2 is an enlarged plan view of the planar light source according to the present embodiment.
FIG. 3A is a diagram showing an example of a cross section in line 3-3 of FIG.
FIG. 3B is a diagram showing another example of the cross section in line 3-3 of FIG.
FIG. 4A is a diagram showing an example of a cross section taken along the line 4-4 of FIG.
FIG. 4B is a diagram showing another example of the cross section taken along the line 4-4 of FIG.

As shown in FIG. 1, the planar light source 100 includes a single wiring board 110, a light guide member 120, a light source 130, and a light-reflecting partition member 140. As shown in FIGS. 3A and 4A, the planar light source 100 further includes a light reflecting member 150, a first translucent member 160, and a first light adjusting member 170. The planar light source 100 further includes a light-reflecting sheet 180 and an adhesive sheet 190. The light-reflecting partition member 140 may be simply referred to as a "partition member 140".

Hereinafter, each part of the planar light source 100 will be described in detail. Hereinafter, as shown in FIG. 1, an example in which a plurality of light sources 130 are arranged in the X direction and the Y direction in the planar light source 100 will be described. However, the number of the light sources 130 to be arranged may be 1 or more, and is not limited to the number shown in FIG. Further, in the following, an example in which one light source member 120 having the same number of light source arrangement portions 121 as the light source 130 is arranged on one wiring board 110 in the planar light source 100 will be described. However, in the planar light source 100, a plurality of light guide members having a size smaller than that of the wiring board 110 in a plan view may be arranged so as to be arranged on one wiring board 110. When a planar light source having a large size is required, a planar light source device in which a plurality of planar light sources 100 are arranged may be created.

As shown in FIGS. 3A and 4A, the wiring board 110 covers the upper surface of the wiring layer 111 and the wiring layer 111, covers the first coating layer 112 made of the resin material, and the lower surface of the wiring layer 111, and is made of the resin material. It has a second coating layer 113 and the like. A pad 114 may be provided on the upper surface of the wiring layer 111 in a region where the electrodes 131b and 131c of the light source 130 are connected via the conductive joining member 135. The pad 114 can be, for example, a plating layer composed of a Ni layer and an Au layer.

The configuration of the wiring board 110 is not limited to this. For example, an adhesive layer (not shown) may be provided between the wiring layer 111 and the coating layers 112 and 113. Further, in FIGS. 3A and 4A, an example in which the wiring layer 111 is one layer is shown, but a plurality of wiring layers 111 are provided between the first coating layer 112 and the second coating layer 113 in the Z direction. You may. When a plurality of wiring layers 111 are provided in the Z direction, an insulating layer and an adhesive layer may be provided between two wiring layers 111 adjacent to each other in the Z direction.

The surface of the wiring board 110 includes an upper surface 110a and a lower surface 110b. The upper surface 110a and the lower surface 110b are, for example, flat surfaces and are substantially parallel to the X and Y directions.

A light guide member 120 is provided above the wiring board 110. The light guide member 120 has translucency with respect to the light emitted from the light source 130. As the material of the light guide member 120, for example, a thermoplastic resin such as acrylic, polycarbonate, cyclic polyolefin, polyethylene terephthalate, polyester, a thermosetting resin such as epoxy or silicone, glass or the like can be used.

As shown in FIG. 1, the light guide member 120 is, for example, a plate-shaped member. However, the light guide member 120 may be a layer instead of a plate-shaped member. When the light guide member 120 is a layer, the light guide member 120 may be a single layer or a plurality of layers. When the light guide member 120 is composed of a plurality of layers, each layer may be laminated with a translucent adhesive sheet. As the material of the translucent adhesive sheet, it is preferable to use the same material as the light guide member 120 so that the formation of an interface between layers can be reduced.

The surface of the light guide member 120 includes an upper surface 120a and a lower surface 120b located on the opposite side of the upper surface 120a. The upper surface 120a and the lower surface 120b are, for example, flat surfaces and are substantially parallel to the upper surface 110a of the wiring board 110.

The light guide member 120 is provided with a light source arranging portion 121. As shown in FIGS. 3A and 4A, the light source arranging portion 121 penetrates the light guide member 120 in the thickness direction (Z direction). However, the light source arranging portion 121 may be a recess provided on the lower surface 120b of the light guide member 120. As shown in FIG. 2, the shape of the light source arrangement portion 121 in a plan view may be circular or rectangular. In the case of a rectangle, the corners of the rectangle may be right angles or curved.

A light source 130 is arranged in the light source arrangement unit 121. The light source 130 is mounted on the upper surface 110a of the wiring board 110. The light source 130 includes, for example, a light emitting element 131, a second translucent member 132, a second light adjusting member 133, and a covering member 134.

The light emitting element 131 has a light emitting unit 131a and a pair of positive and negative electrodes 131b and 131c. The light emitting unit 131a includes, for example, a semiconductor growth substrate and a semiconductor laminated structure, and the semiconductor growth substrate is located above the semiconductor laminated structure. The semiconductor laminated structure includes an In _x Al _y Ga _1-x-y N (0 ≦ x, 0 ≦ y, x + y ≦ 1) layer, and emits blue light from the light emitting element 131. The electrodes 131b and 131c are joined to the wiring board 110 by a conductive joining member 135.

The light emitting unit 131a includes an n-type semiconductor layer and a p-type semiconductor layer, and a light emitting layer sandwiched between them. The light emitting layer may have a structure such as a double heterojunction or a single quantum well (SQW), or may have a structure having a group of active layers such as a multiple quantum well (MQW). good. The light emitting unit 131a is configured to be capable of emitting visible light or ultraviolet light. The light emitting portion 131a including a light emitting layer, for example _{In x Al y Ga 1-xy} N (0 ≦ x, 0 ≦ y, x + y ≦ 1) may include.

The light emitting unit 131a may have a structure including one or more light emitting layers between the n-type semiconductor layer and the p-type semiconductor layer, or may include the n-type semiconductor layer, the light emitting layer, and the p-type semiconductor layer. The structure included in order may have a structure in which the structure is repeated a plurality of times. When the light emitting unit 131a includes a plurality of light emitting layers, it may include light emitting layers having different light emitting peak wavelengths, or may include light emitting layers having the same light emitting peak wavelength. The same emission peak wavelength includes a case where there is a variation of about several nm. The combination of emission peak wavelengths between the plurality of light emitting layers can be appropriately selected. For example, when the light emitting unit 131a includes two light emitting layers, blue light and blue light, green light and green light, red light and red light, ultraviolet light and ultraviolet light, blue light and green light, blue light and red light, or , The light emitting layer can be selected by a combination of green light and red light. Each light emitting layer may include a plurality of active layers having different emission peak wavelengths, or may include a plurality of active layers having the same emission peak wavelength.

The second translucent member 132 covers, for example, the upper surface and the side surface of the light emitting portion 131a. The second translucent member 132 has translucency with respect to the light emitted by the light emitting unit 131a. The second translucent member 132 includes, for example, a base material made of a translucent material and a plurality of wavelength conversion particles dispersed in the base material.

As the material of the base material, for example, silicone resin, epoxy resin, glass, or the like can be used. As the wavelength conversion particles, for example, a phosphor can be used. The phosphor is excited by the light emitted by the light emitting element 131, and emits light having a wavelength different from the wavelength of the light emitted by the light emitting element 131. For example, as the phosphor, yttrium aluminum garnet (YAG) -based phosphor (for example, Y ₃ (Al, Ga) ₅ O ₁₂ : Ce), β-sialon phosphor (for example, (Si, Al) ₃ (O,) N) ₄ : Eu), yttrium aluminum garnet-based phosphor (for example, Lu ₃ (Al, Ga) ₅ O ₁₂ : Ce), terbium aluminum garnet-based phosphor (for example, Tb ₃ (Al, Ga)) _{5 O 12: Ce)),} α based sialon phosphor _{(e.g., Ca (Si, Al) 12} (O, N) 16: Eu), KSF phosphor _{(e.g., K 2 SiF 6: Mn)} , KSAF system Fluorescent phosphors such as phosphors (eg, K ₂ (Si, Al) F ₆ : Mn) or MGF-based phosphors, nitride phosphors (CASN-based phosphors (eg, CaAlSiN ₃ : Eu)) or SCASSN-based Fluorescent materials (eg, (Sr, Ca) AlSiN ₃ : Eu), etc.), phosphors having a perovskite structure (eg, CsPb (F, Cl, Br, I) ₃ ), quantum dot phosphors (eg, CdSe, InP). , AgInS ₂ or AgInSe ₂ ) and the like can be used. The second translucent member 132 may contain a plurality of types of phosphors. White light can be emitted from the light source 130 by combining the phosphor contained in the second translucent member 132 and the light emitting element 131 that emits blue light. Further, when the second translucent member 132 does not contain a phosphor, the blue light from the light emitting element can be emitted as the light from the light source 130.

The second light adjusting member 133 reflects a part of the light emitted from the light emitting element 131 and transmits the other part of the light emitted from the light emitting element 131. The second light adjusting member 133 covers the upper surface of the second translucent member 132. The second light adjusting member 133 is, for example, a resin containing a light-reflecting material. Specifically, as the second light adjusting member 133, a silicone resin containing titanium oxide, an epoxy resin, or the like can be used as the light-reflecting material. The second light adjusting member 133 may have one layer or two or more layers.

The covering member 134 covers the lower surface of the second translucent member 132 and the lower surface of the light emitting portion 131a. The covering member 134 is, for example, a resin containing a light-reflecting material. Specifically, as the coating member 134, a silicone resin containing titanium oxide, an epoxy resin, or the like can be used as the light-reflecting material.

As shown in FIG. 2, the shape of the light source 130 in a plan view is, for example, a quadrangle. Hereinafter, the center C of the light source 130 in a plan view is also simply referred to as “center C”. In the present embodiment, the center C is located at the intersection of the diagonal lines of the light source 130 in a plan view. Further, the center C substantially coincides with the center of the light source arranging portion 121 in a plan view.

The light source 130 may be configured not to be provided with the second light adjusting member 133. Further, the light source 130 may be configured not to be provided with the covering member 134. Further, the light source 130 may have a configuration of only the light emitting element 131, or may have a configuration in which the second light adjusting member 133 is provided on the upper surface of the light emitting element 131.

The light source 130 may include a resin containing a light-reflecting material that surrounds the side surface of the light-emitting element 131, and a translucent member that covers the upper surface of the light-emitting element 131 and the upper surface of the resin containing the light-reflecting material. This translucent member may contain a phosphor. In this case, a translucent joining member for adhering the light emitting element 131 and the translucent member may be provided between the light emitting element 131 and the translucent member.

The light source 130 described above has one light emitting element 131, but may include a plurality of light emitting elements. The plurality of light emitting elements may have the same peak wavelength or may have different peak wavelengths. As a combination of those having different peak wavelengths, for example, a light emitting element that emits red light, a light emitting element that emits blue light, and a light emitting element that emits green light can be used.

In the cross-sectional view taken along the line 4-4 of FIG. 2 (FIGS. 4A and 4B), the width of the light source 130 in the X direction can be 700 μm or more and 1000 μm or less, and the thickness of the light source 130 in the Z direction is 300 μm or more. It can be 400 μm or less. As a result, the light source 130 can be made thin. By setting the ratio of the thickness to the width of the light source 130 to 0.4 or more, it is possible to suppress a decrease in light extraction efficiency due to the thinning.

Further, the width of the light emitting element 131 in the X direction can be 350 μm or more and 550 μm or less, and the thickness of the light emitting portion 131a of the light emitting element 131 in the Z direction can be 100 μm or more and 200 μm or less. In the second translucent member 132, the width in the X direction from the side surface of the light emitting portion 131a of the light emitting element 131 to the side surface of the second translucent member 132 can be 75 μm or more and 325 μm or less. This width is more preferably 150 μm or more and 250 μm or less. This width is even more preferably 180 μm or more and 210 μm or less. As a result, the width can be increased in the X direction from the side surface of the light emitting portion 131a of the light emitting element 131 to the side surface of the second translucent member 132 with respect to the deviation from the center C of the light source 130. Therefore, even if the light emitting element 131 is deviated from the center C of the light source 130 in the X direction, the difference in chromaticity of the light emitted from both side surfaces of the light emitting element 131 can be reduced. Further, the thickness in the Z direction from the upper surface of the light emitting portion 131a to the upper surface of the second translucent member 132 can be 15 μm or more and 215 μm or less. This thickness is more preferably 50 μm or more and 150 μm or less. This thickness is even more preferably 90 μm or more and 120 μm or less. As a result, although it is thin, it is possible to secure a region that can be emitted from the side of the light source 130, so that the efficiency of extracting light from the light emitting element 131 is improved.

The light guide member 120 is provided with a groove 122 so as to surround the light source arrangement portion 121 in a plan view.

As shown in FIGS. 3A and 4A, the groove 122 is, for example, a recess provided on the upper surface 120a. The cross-sectional shape of the groove 122 is trapezoidal. Specifically, the groove 122 has a pair of side surfaces 126a and 126b that are inclined in the Z direction and face each other, and a bottom surface 126c that is located between the pair of side surfaces 126a and 126b. Since each of the pair of side surfaces 126a and 126b is inclined, the light reflected by the lower surface 120b of the light guide member 120 among the light from the light source 130 can easily pass through. Light is more easily transmitted when the pair of side surfaces 126a and 126b are inclined, as compared with the case where each of the pair of side surfaces in the groove is vertical, among the light from the light source 130, the light guide member 120. This is because the incident angle at which the light reflected by the lower surface 120b of the groove 122 is incident on the side surfaces 126a and 126b of the groove 122 becomes smaller. The surface connecting each of the pair of side surfaces 126a and 126b and the bottom surface 126c is a curved surface. However, the cross-sectional shape of the groove 122 is not limited to this. For example, the cross-sectional shape of the groove 122 may be rectangular, substantially V-shaped, substantially U-shaped, or may have a narrow opening side. Further, the groove 122 may penetrate the light guide member 120 in the Z direction, or may be a recess provided on the lower surface 120b of the light guide member 120.

Further, as shown in FIGS. 3B and 4B, when the groove 122 penetrates the light guide member 120 in the Z direction, the recess 181 is provided in the region of the light reflective sheet 180 located directly below the groove 122. It may have been. The side surface of the groove 122 and the side surface of the recess 181 may be flush with each other. That is, one groove may be formed from the light guide member 120 to the light reflecting sheet 180 by the groove 122 and the recess 181 penetrating the light guide member 120 in the Z direction.
In FIG. 4B, the partition member 140 is filled from the groove 122 to the recess 181. However, the present invention is not limited to this, and the surfaces of the groove 122 and the recess 181 may be covered in layers.

The pattern of the wiring layer 111 in the planar light source 100 is preferably formed so as to reduce the area overlapping the groove 122 in a plan view. Specifically, rather than arranging the wiring layer 111 so as to overlap the extending portion of the groove 122 in the same direction in the plan view, the wiring layer 111 and the extending portion of the groove 122 are arranged so as to intersect each other in the plan view. Is preferable. This makes it possible to reduce the risk of damaging the wiring layer 111 when forming the groove 122 with a cutting tool such as a dicing saw.

As shown in FIG. 2, in the planar light source 100, the grooves 122 are provided, for example, in a grid pattern. Therefore, the upper surface 120a of the light guide member 120 is divided into a plurality of light emitting regions S by the grooves 122. The shape of each light emitting region S is similar to the shape of the light source 130, for example, and is a quadrangle. In a plan view, the center C is located at the intersection of the diagonal lines of the light emitting region S. However, the grooves 122 may not be provided in a grid pattern, and the shape of each light emitting region S may not be a quadrangle. For example, the groove 122 may be provided so that each light emitting region S has a polygonal shape such as a triangle or a hexagon. Further, the center C does not have to be located at the intersection of the diagonal lines of the light emitting region S. Hereinafter, the direction in which the diagonal line of the light emitting region S extends is also referred to as “diagonal direction W”. In the case of FIG. 2, the diagonal direction W is a direction inclined by 45 degrees from the X direction (or Y direction) on the XY plane.

The groove 122 connects, for example, two first groove portions 122a extending in the Y direction, two second groove portions 122b extending in the X direction, and the first groove portion 122a and the second groove portion 122b around one light source 130. It has two joint groove portions 122c.

Hereinafter, the portion of the light guide member 120 including the groove 122 and surrounding the light emitting region S in a plan view is referred to as a “partition defining portion 123”. In the present embodiment, the groove 122 is a recess that continuously surrounds the light emitting region S and is provided on the upper surface 120a of the light guide member 120. Therefore, as shown in FIGS. 3A and 4A, the section defining portion 123 includes a groove 122 and a portion of the light guide member 120 located directly below the groove 122.

When the groove 122 continuously surrounds the light emitting region S and is a recess provided on the lower surface 120b of the light guide member 120, the partition defining portion 123 is directly above the groove 122 and the groove 122 in the light guide member 120. It consists of the part where it is located. Further, when the groove 122 continuously surrounds the light emitting region S and penetrates the light guide member 120 in the thickness direction, the partition defining portion 123 is composed of the groove 122. The form in which the groove does not continuously surround the light emitting region will be described in the second embodiment described later.

As shown in FIG. 2, the section defining portion 123 has a first extending portion 123a, a second extending portion 123b, and a connecting portion 123c. The first stretched portion 123a stretches in the Y direction, and the second stretched portion 123b stretches in the X direction. The connecting portion 123c is a portion that is connected to the first extending portion 123a and the second extending portion 123b and is extended in the X direction and the Y direction (in one section defining portion 123, it has an L shape as shown in FIG. 2). , When a plurality of division defining portions 123 are arranged, it is a cross shape). The connecting portion 123c may be a rectangular portion in which each of the first extending portion 123a and the second extending portion 123b is virtually extended and overlapped.

The first extending portion 123a is composed of a portion directly below the first groove portion 122a in the first groove portion 122a and the light guide member 120. The second extending portion 123b is composed of a second groove portion 122b and a portion directly below the second groove portion 122b in the light guide member 120. The coupling portion 123c is composed of a coupling groove portion 122c and a portion directly below the coupling groove portion 122c in the light guide member 120.

Further, the division defining portion 123 has a first portion 124 farthest from the center C and a second portion 125 closest to the center C.

The position P1 farthest from the center C in the section defining portion 123 is located at the connecting portion 123c. More specifically, the farthest position P1 is located at the angle Sc of the light emitting region S of the other planar light source 100 adjacent in the diagonal direction W in the plan view. Therefore, the first portion 124 is a portion of the partition defining portion 123 that includes the farthest position P1 and has a thickness in a direction orthogonal to the diagonal W and Z directions.

The position P2 closest to the center C in the section defining portion 123 is located, for example, in the first extending portion 123a or the second extending portion 123b. More specifically, the closest position P2 is located on the outer peripheral edge of the light emitting region S in a plan view, and is located on a straight line parallel to the X direction (or Y direction) passing through the center C in a plan view. The second portion 125 is a portion of the partition defining portion 123 that includes the closest position P2 and has a thickness in the Y direction.

A light-reflecting partition member 140 is provided in the groove 122 of the partition defining portion 123. In FIG. 2, in order to make the explanation easy to understand, the range in which the partition member 140 is provided is shown by a dot pattern. The partition member 140 is, for example, a resin containing a light-reflecting material. Specifically, as the partition member 140, a silicone resin containing titanium oxide, an epoxy resin, or the like can be used as the light-reflecting material. The content of titanium oxide can be 1% by weight or more and 70% by weight or less. The partition member 140 can be formed by a printing method, a spray method, an inkjet method, or a potting method. With the inkjet method, the partition member 140 can be arranged with high accuracy.

In the case of the potting method, the partition member is located in the midpoint region between the adjacent coupling groove portions 122c (that is, the region intersecting the straight line extending in the X direction or the Y direction from the center of the light source in the first groove portion 122a or the second groove portion 122b). 140 raw materials can be potted. When the raw material of the partition member 140 contains a particulate light-reflecting material and a liquid resin, the resin after potting is spread in the first groove portion 122a or the second groove portion 122b by lowering the viscosity of the resin. Can be done. Further, since the viscosity of the resin is low, the light-reflecting material tends to sink and is difficult to disperse. Thereby, the concentration of the light-reflecting material in the potted region (that is, near the midpoint between the adjacent coupling groove portions 122c) can be made higher than the concentration of the light-reflecting material in the region of the coupling groove portion 122c. In order to arrange the partition member 140 in a predetermined area, a mask can be provided in the area where the partition member 140 is not arranged.

The partition member 140 can cover the upper surface 120a of the light guide member 120 at the center of the first groove portion 122a and the second groove portion 122b in the stretching direction. When the brightness of the midpoint region between the coupling groove portions 122c is higher than the brightness of the region other than the midpoint region between the coupling groove portions 122c (for example, the region of the coupling groove portion 122c), in the region of the midpoint between the adjacent coupling groove portions 122c. By arranging the partition member 140 on the upper surface of the light guide member, the brightness can be suppressed. On the other hand, at the ends of the first groove portion 122a and the second groove portion 122b in the stretching direction, the partition member 140 may or may not cover the upper surface 120a of the light guide member 120. Further, the width of the partition member 140 covering the upper surface 120a of the light guide member 120 may be the same from the center to the end in the extending direction of the first groove portion and the second groove portion, or gradually or gradually narrows. You may. The width of the partition member 140 covering the upper surface 120a of the light guide member 120 may be a value within 1/10 of the distance between the adjacent first groove portions 122a (or the distance between the adjacent second groove portions 122b). can.

In the present embodiment, the cross-sectional area of the compartment member 140 in the first portion 124 is smaller than the cross-sectional area of the compartment member 140 in the second portion 125. The “cross-sectional area of the partition member 140 in the first portion 124” means the area of the partition member 140 in the cross section (cross section in line 3-3 of FIG. 2) including the center C and the position P1 farthest from the light source. Similarly, the "cross-sectional area of the partition member 140 in the second portion 125" refers to the area of the partition member 140 in the cross section including the center C and the position P2 closest to the light source (cross section in line 4-4 of FIG. 2). means. The “small cross-sectional area” includes the case where the cross-sectional area of the partition member 140 in the first portion 124 is 0 (zero).

Specifically, as shown in FIG. 2, the partition member 140 is provided in the first groove portion 122a corresponding to the first stretched portion 123a and the second groove portion 122b corresponding to the second stretched portion 123b. Therefore, as shown in FIG. 4A, the partition member 140 is provided in the groove 122 in the second portion 125. The partition member 140 may be filled so as to fill the groove 122 in the second portion 125. By filling the groove 122 with the partition member 140, the light reflectivity can be improved. When filling the partition member 140, the upper surface of the partition member 140 may be a flat surface, a convex surface, or a concave surface. The partition member 140 may be provided in the entire area of the first groove portion 122a in the Y direction and the entire area of the second groove portion 122b in the X direction. The partition member 140 may cover the surface of the first groove portion 122a or the second groove portion 122b in a layered manner in a cross-sectional view. By providing the partition member 140 in a layered manner, a part of light can be transmitted. When the partition members 140 are provided in layers, the partition member 140 provided on the bottom surface 126c of the groove 122 may be thicker than the partition member 140 provided on the side surfaces 126a and 126b of the groove 122. Further, the partition member 140 may protrude upward from the upper surface 120a of the light guide member 120.

On the other hand, as shown in FIG. 2, the partition member 140 is not provided in the coupling groove portion 122c. That is, the partition member 140 is not provided on the coupling groove portion 122c corresponding to the coupling portion 123c, and the coupling portion 123c in the partition defining portion 123 is composed of only the light guide member 120. As shown in FIG. 3A, for example, an air layer K exists in the coupling groove portion 122c, and the entire surface of the coupling groove portion 122c is in contact with the air layer K. As described above, the cross-sectional area of the partition member 140 provided in the first portion 124 is 0 (zero), which is smaller than the cross-sectional area of the partition member 140 provided in the second portion 125. However, the cross-sectional area of the compartment member 140 of the first portion 124 may be smaller than the cross-sectional area of the compartment member 140 of the second portion 125, and the compartment member 140 may be provided in the first portion 124. In the first portion 124, the surface of the groove 122 of the light guide member 120 may be coated with an antireflection film that does not prevent the light from the light source 130 from being transmitted. As the antireflection film, for example, silicone can be used.

As described above, the cross-sectional area of the partition member 140 provided in the groove 122 in the first portion 124 is smaller than the cross-sectional area of the partition member 140 provided in the groove 122 in the second portion 125. Therefore, the transmittance of the first portion 124 is higher than the transmittance of the second portion 125. The “transmittance of the first portion 124” is the ratio of the light LA traveling toward the position P1 side farthest from the center C side in the direction orthogonal to the Z direction passing through the first portion 124. Similarly, the "transmittance of the second portion 125" is the ratio of the light LB traveling from the center C side toward the closest position P2 side in the direction orthogonal to the Z direction passing through the second portion 125. ..

When the partition member 140 is arranged in both the first portion 124 and the second portion 125, the partition member 140 of the first portion 124 is arranged in order to make the transmittance of the first portion 124 higher than that of the second portion 125. The concentration of the light-reflecting material contained in the second portion 125 may be smaller than the concentration of the light-reflecting material contained in the partition member 140 of the second portion 125.

Further, the partition member 140 may be provided in the first stretched portion 123a because the transmittance at the end portion in the Y direction is larger than the transmittance at the center in the Y direction. The partition member 140 can increase the coating amount or increase the concentration of the light-reflecting material at the center in the Y direction, and decrease the coating amount or decrease the concentration of the light-reflecting material at the end in the Y direction. .. The partition member 140 may continuously or stepwise reduce the coating amount or the concentration of the light-reflecting material from the center in the Y direction toward the end in the Y direction. The same applies to the second stretched portion 123b.

The light emitting region S can be partitioned by providing the light guide member 120 with a groove 122 surrounding the light source arranging portion 121 and providing the partition member 140 in the groove 122. However, the first portion 124, which is the farthest from the center C of the light source 130, tends to be darker than the second portion 125, which is the closest to the center C, because the distance from the light source 130 is long. Therefore, for example, when the inside of the groove 122 is uniformly filled with the partition member 140, the vicinity of the first portion 124 farthest from the center C remains dark and becomes conspicuous as a dark portion. In particular, when the light sources 130 located in the four light emitting regions S adjacent to the first first portion 124 are turned on at the same time, the first first portion 124 described above is more conspicuous as a dark portion.

On the other hand, in the present embodiment, the transmittance of the first portion 124 farthest from the light source 130 is higher than the transmittance of the second portion 125 closest to the light source 130. By increasing the transmittance of the first portion 124, the amount of light passing through the first portion 124 can be increased, so that the vicinity of the first portion 124 can be brightened. As a result, it is possible to suppress the vicinity of the first portion 124 from being conspicuous as a dark portion, and a planar light source in which the brightness unevenness in the light emitting region is suppressed can be obtained. In particular, when four adjacent light emitting regions S are arranged two-dimensionally, it is effectively suppressed from being conspicuous as a dark part when the light sources 130 located in the first first portion 124 and the adjacent four light emitting regions S are turned on at the same time. It is possible to obtain a planar light source in which uneven brightness in the light emitting region is suppressed.

As shown in FIG. 3A, a light reflective sheet 180 is provided between the wiring board 110 and the light guide member 120. The light-reflecting sheet 180 reflects a part of the light emitted from the light source 130. As the light-reflective sheet 180, a resin sheet containing a large number of voids (for example, a foamed resin sheet), a resin sheet containing a light-reflective material such as titanium oxide, or the like can be used. The light reflecting sheet 180 is provided with a through hole 180a at a position where it overlaps with the light source arranging portion 121 in a plan view.

An adhesive sheet 190 is provided between the wiring board 110 and the light-reflecting sheet 180. The adhesive sheet 190 is adhered to the wiring board 110 and the light reflective sheet 180. The adhesive sheet 190 is provided with a through hole 190a at a position where it overlaps with the light source arranging portion 121 in a plan view. An adhesive sheet may also be provided between the light guide member 120 and the light reflective sheet 180.

A light reflecting member 150 is provided, for example, on a region of the upper surface 110a of the wiring board 110 that is located in the light source arranging portion 121 and is located between the light source 130 and the adhesive sheet 190. As a result, it is possible to prevent a part of the light emitted from the light source 130 from being absorbed by the wiring board 110, and it is possible to reduce a decrease in brightness around the light source 130.

Instead of providing the light-reflecting member 150, the light-reflecting sheet 180 may extend into the light source arrangement portion 121 of the light guide member 120. The decrease in brightness around the light source 130 can be reduced, and the number of members can be reduced by not providing the light reflecting member 150. The light reflective sheet 180 preferably extends to a position overlapping the light source 130 in a plan view, that is, between the light source 130 and the wiring board 110 in a cross-sectional view.

The light reflecting member 150 surrounds the light source 130. The light-reflecting member 150 is, for example, a resin containing a light-reflective material. Specifically, as the light-reflecting member 150, a silicone resin containing titanium oxide, an epoxy resin, or the like can be used as the light-reflecting material.

The light source arranging portion 121 is filled with, for example, the first translucent member 160. The first translucent member 160 has translucency with respect to the light emitted from the light source 130. As the material of the first translucent member 160, for example, a thermosetting resin such as epoxy or silicone can be used. In particular, the material of the first translucent member 160 has the same material as the light guide member 120 or the refractive index with respect to the light emitted from the light source 130 so that the light emitted from the light source 130 is easily incident on the light guide member 120. It is preferable to use a material having a refractive index smaller than that of the light guide member 120. The first translucent member 160 may include wavelength conversion particles. When the light emission color from the light source 130 is measured after mounting the light source 130 and the light guide member 120 on the wiring substrate 110, the first translucent member 160 containing the wavelength conversion particles is provided even if the emission color deviates from the desired emission color. By providing it, it is possible to adjust it so as to obtain a desired emission color. As a result, it is not necessary to replace the light source 130, and the cost can be suppressed. Further, the light source arranging portion 121 may not be filled by the first translucent member 160 and may be hollow.

The upper surface of the first light transmissive member 160 is covered with the first light adjusting member 170. In FIGS. 3A and 4A, the first light adjusting member 170 is in contact with, for example, the first translucent member 160 and the light guide member 120, but may be in contact with only the first translucent member 160.

The first light adjusting member 170 reflects a part of the light emitted from the light source 130 and transmits the other part of the light emitted from the light source 130. The first light adjusting member 170 is, for example, a resin containing a light-reflecting material. Specifically, as the first light adjusting member 170, a silicone resin containing titanium oxide, an epoxy resin, or the like can be used as the light-reflecting material.

As shown in FIG. 2, the shape of the first light adjusting member 170 in a plan view is substantially similar to the light emitting region S and is a quadrangle. However, the shape of the first light adjusting member 170 is not limited to this. For example, the shape of the first light adjusting member 170 in a plan view does not have to be substantially similar to the light emitting region S. Further, the shape of the first light adjusting member 170 in a plan view may be a polygon such as a triangle or a hexagon, or may be a circular shape.

Next, the operation of the planar light source 100 according to the present embodiment will be described.
FIG. 5 is a cross-sectional view taken along the line 4-4 of FIG. 2, which is a cross-sectional view showing an example of light emitted from a light source.
FIG. 6 is a cross-sectional view taken along the line 3-3 of FIG. 2, which is a cross-sectional view showing an example of light emitted from a light source.

As shown in FIGS. 5 and 6, the first light L1a of the light L1 emitted from the upper surface of the light emitting element 131 passes through, for example, the second light adjusting member 133 and the first light adjusting member 170. Further, the second light L1b of the light L1 is reflected by the first light adjusting member 170 after passing through the second light adjusting member 133, and is reflected by the lower surface 120b of the light guide member 120 or the light reflecting member 150. Head. Further, the third light L1c of the light L1 is reflected by, for example, the second light adjusting member 133, and heads toward the lower surface 120b of the light guide member 120 or the light reflecting member 150.

In this way, the second light adjusting member 133 and the first light adjusting member 170 reflect a part of the light L1. As a result, in the light irradiation region of the planar light source 100, it is possible to prevent the brightness of the region located directly above the light source 130 from becoming higher than the brightness of the other regions. As a result, it is possible to suppress the occurrence of uneven brightness.

As shown in FIG. 5, a part of the second light L1b of the light L1, a part of the third light L1c of the light L1, and a part of the light L2 emitted from the side surface of the light emitting element 131 are, for example, light reflective. After being reflected by one or more members of the member 150, the first light adjusting member 170, and the light reflective sheet 180, the second portion 125 of the partition defining portion 123 is reached. Most of the light that reaches the second portion 125 is reflected by the partition member 140.

As shown in FIG. 6, the other part of the second light L1b of the light L1, the other part of the third light L1c of the light L1, and the other part of the light L2 emitted from the side surface of the light emitting element 131 are For example, after being reflected by one or more members of the light-reflecting member 150, the first light adjusting member 170, and the light-reflecting sheet 180, the light-reflecting member 150 reaches the first portion 124 of the partition defining portion 123. The transmittance of the first portion 124 of the partition defining portion 123 is higher than the transmittance of the second portion 125 of the partition defining portion 123. Therefore, the amount of light transmitted through the first portion 124 is larger than the amount of light transmitted through the second portion 125. As a result, it is possible to prevent the vicinity of the first portion 124 from being conspicuous as a dark portion.

The planar light source 100 can be applied to, for example, the backlight of a liquid crystal display. In a backlight in which a light emitting region S is divided for each of a plurality of light sources 130, local dimming can be performed with high accuracy by individually adjusting the output of each light source 130.

Next, the effect of this embodiment will be described.
The planar light source 100 according to the present embodiment includes a light source 130, a light guide member 120, and a partition member 140. The light guide member 120 has a light source arranging portion 121 in which the light source 130 is arranged, and a partition defining portion 123 including a groove 122 surrounding the light source arranging portion 121. The partition member 140 is provided in the partition defining portion 123. In a plan view, the transmittance of the first portion 124 farthest from the center C of the light source 130 in the partition defining portion 123 is higher than the transmittance of the second portion 125 closest to the center C of the light source 130 in the partition defining portion 123. As a result, it is possible to prevent the vicinity of the first portion 124 from being conspicuous as a dark portion. As a result, it is possible to realize the planar light source 100 in which the dark portion can be suppressed from being conspicuous in the region farthest from the light source in the partition defining portion 123 and the brightness unevenness in the light emitting region is suppressed.

Further, the cross-sectional area of the partition member 140 provided in the groove 122 in the first portion 124 is smaller than the cross-sectional area of the partition member 140 provided in the groove 122 in the second portion 125. Therefore, the transmittance of the first portion 124 can be made higher than the transmittance of the second portion 125.

Further, the first portion 124 is not provided with the partition member 140. That is, the first portion 124 is composed of only the light guide member 120. Therefore, it is possible to prevent the vicinity of the first portion 124 from being conspicuous as a dark portion.

Further, the section defining portion 123 includes a first extending portion 123a extending in the first direction (Y direction) and a first extending portion 123a.
It has a second stretched portion 123b extending in a second direction (X direction) intersecting the first direction, and a connecting portion 123c for connecting the first stretched portion 123a and the second stretched portion 123b. The first portion 124 is located at the joint portion 123c. The second portion 125 is located at the first stretched portion 123a. Therefore, it is possible to prevent the vicinity of the connecting portion 123c from being conspicuous as a dark portion.

Further, the first stretched portion 123a and the second stretched portion 123b are provided with the partition member 140, whereas the joint portion 123c is not provided with the partition member 140. Therefore, the vicinity of the connecting portion 123c can be brightened, and the conspicuousness as a dark portion can be suppressed in a wide range.

In the present embodiment, it will be described that in FIG. 2, the vicinity of the joint portion 123c located at the upper right (+ X direction, + Y direction from the light source 130) of the four joint portions 123c of the partition defining portion 123 can be suppressed from being conspicuous as a dark portion. However, if all four coupling portions 123c are the points farthest from the light source in the partition defining portion 123, it is possible to suppress the conspicuous dark portion in the vicinity of all four coupling portions 123c. The same applies to the following embodiments.

<First modification of the first embodiment>
Next, a first modification of the first embodiment will be described.
FIG. 7 is a plan view showing a planar light source according to this modification.
The planar light source 200 according to this modification is different from the planar light source 100 according to the first embodiment in the configuration of the partition member 240. In the following description, as a general rule, only the differences from the first embodiment will be described. The same applies to the first embodiment except for the matters described below.

As shown in FIG. 7, the first groove portion 122a has a first side surface 226a facing each other, a second side surface 226b, and a bottom surface 226c located between the first side surface 226a and the second side surface 226b. A partition member 240 is provided in the first groove portion 122a. The partition member 240 is, for example, a resin containing a light-reflecting material.

The partition member 240 is arranged by providing a first light reflecting portion 241 arranged with a plurality of first gaps D1 on the first side surface 226a and providing a plurality of second gaps D2 on the second side surface 226b. It also has a second light reflecting unit 242. The plurality of first gaps D1 face the second light reflecting portion 242. Further, the plurality of second gaps D2 face the first light reflecting portion 241. Similarly, the second groove portion 122b may have a first light reflecting portion 241 and a second light reflecting portion 242.
As shown in FIG. 7, the partition member 240 is also provided on the bottom surface 226c, and the first light reflecting portion 241 and the second light reflecting portion 242 may be integrated. The partition member 240 may not be arranged on the bottom surface 226c, and the first light reflecting portion 241 may be divided into a plurality of parts via the first gap D1. Similarly, the second light reflecting unit 242 may be divided into a plurality of parts via the second gap D2.
As shown in FIG. 7, the length of the first gap D1 in the Y direction may be shorter than the length of the second light reflecting portion 242 in the Y direction, or may be the same as the length of the second light reflecting portion 242 in the Y direction. good. Similarly, the length of the second gap D2 in the Y direction may be shorter than the length of the first light reflecting portion 241 in the Y direction as shown in FIG. 7, or the length of the first light reflecting portion 241 in the Y direction. May be the same as.

Next, the operation of the planar light source 200 according to this modification will be described. Hereinafter, an example will be described in which the planar light source 200 has a first light emitting region S1 and a second light emitting region S2 adjacent to the first light emitting region S1 in the X direction.

First, the action and effect when either the light source 130 located in the first light emitting region S1 or the light source 130 located in the second light emitting region S2 is turned on will be described below. Here, the case where the light source 130 located in the first light emitting region S1 is turned on will be described.

A part L4 of the light emitted from the light source 130 located in the first light emitting region S1 travels in the light guide member 120 and passes through, for example, the first gap D1. The light L4 that has passed through the first gap D1 is reflected by the second light reflecting unit 242. Therefore, it is possible to prevent the light L4 emitted from the light source 130 from being incident on the second planar light source 200b while passing through the groove 122. As a result, the groove 122 can be brightened while being partitioned by the side surface 126b of the groove 122. The groove 122 can also be brightened. Therefore, the brightness of the outer periphery of the first light emitting region S1 can be improved.

Next, the action and effect when the light source 130 located in the first light emitting region S1 and the light source 130 located in the second light emitting region S2 are turned on at the same time will be described.

A part L4 of the light emitted from the light source 130 located in the first light emitting region S1 travels in the light guide member 120 and passes through, for example, the first gap D1. The light L4 that has passed through the first gap D1 is reflected by the second light reflecting unit 242.

Similarly, a part L5 of the light emitted from the light source 130 located in the second light emitting region S2 travels in the light guide member 120 and passes through, for example, the second gap D2. The light L5 that has passed through the second gap D2 is reflected by the first light reflecting unit 241.

When the light source 130 located in the first light emitting region S1 and the light source 130 located in the second light emitting region S2 are turned on at the same time, the region (groove 122) between the first light emitting region S1 and the second light emitting region S2 is also bright. (Suppressing that the groove 122 is conspicuous as a dark portion), it is required to form a light emitting region in which the first light emitting region S1 and the second light emitting region S2 are integrated. In the present embodiment, the groove 122 located between the first light emitting region S1 and the second light emitting region S2 can also be brightened (suppressing that the groove 122 stands out as a dark portion), and the first light emitting region S1 and the first light emitting region S1 and the first A light emitting region in which the two light emitting regions S2 are integrated can be obtained.

From the above, in the case of the planar light source 200 of the modified example of the present embodiment, when only the light source 130 located in one of the adjacent light emitting regions S is turned on, the light is adjacent to the groove 122. It can be partitioned so as not to enter the light emitting region S. Further, even when the light sources 130 of the plurality of light emitting regions S are turned on at the same time, the grooves 122 located between the light emitting regions S can be brightened so as not to become dark areas.

The dimensions of each first gap D1 in the Y direction do not have to be the same. Similarly, the dimensions of each second gap D2 in the Y direction do not have to be the same. For example, the first gap D1 may become larger toward the end of the first groove portion 122a in the Y direction. Similarly, the second gap D2 may become larger toward the end of the first groove portion 122a in the Y direction. As a result, it is possible to brighten the region of the groove 122 that tends to be a dark portion (the end portion of the first groove portion 122a in the Y direction).

Next, the effect of this modification will be described.
In this modification, the groove 122 of the section defining portion 123 has a first side surface 126a and a second side surface 126b facing each other. The partition member 240 is provided with a plurality of first light reflecting portions 241 arranged with a first gap D1 between them on the first side surface 126a, and a second gap D2 between them on the second side surface 126b. It has a plurality of second light reflecting units 242 arranged. The first gap D1 faces one of the plurality of second light reflecting portions 242. The second gap D2 faces one of the plurality of first light reflecting portions 241. As a result, when the light sources 130 in the plurality of light emitting areas S are turned on at the same time, the grooves 122 located between the light emitting areas S can be brightened so as not to become dark areas. Further, when only the light source 130 located in one of the adjacent light emitting regions S is turned on, the groove 122 can be used to partition the light so that the light does not enter the adjacent light emitting region S.

<Second variant of the first embodiment>
Next, a second modification of the first embodiment will be described.
FIG. 8 is a plan view showing a planar light source according to this modification.
The planar light source 300 according to this modification is different from the planar light source 100 according to the first embodiment in the configuration of the groove 322.

A groove 322 surrounding the light source arranging portion 121 is provided on the upper surface 120a of the light guide member 120. The groove 322 connects two first groove portions 322a extending in the Y direction, two second groove portions 322b extending in the X direction, and the first groove portion 322a and the second groove portion 322b around one light source 130, for example. It has two joint groove portions 322c and.

The side surface 326c of the groove in the connecting portion 323c connecting the side surface 326a of the groove in the first extending portion 323a and the side surface 326b of the groove in the second extending portion 323b is curved in a plan view. The side surface 326a of the first groove portion 322a and the side surface 326b of the second groove portion 322b are connected by the side surface 326c of the coupling groove portion 322c, and the side surface 326c of the coupling groove portion 322c is a curved surface that is convex toward the direction away from the light source 130. be. Therefore, the shape of the light emitting region S in a plan view is a substantially quadrangle with rounded corners. In this modification, the coupling groove portion 322c is a portion that is coupled to the first groove portion 322a and the second groove portion 322b and is extended in the X direction and the Y direction (in one section defining portion 323, as shown in FIG. 8). It is L-shaped, and is cross-shaped when a plurality of partition defining portions 323 are arranged.

Since the side surface 326c of the coupling groove portion 322c is curved, the light passing through the side surface 326c of the coupling groove portion 322c is refracted and collected. Therefore, it is possible to improve the brightness in the vicinity of the coupling groove portion 322c and suppress the vicinity of the coupling groove portion 322c from being conspicuous as a dark portion.

The section defining portion 323 includes a groove 322 and a portion of the light guide member 120 located directly below the groove 322. Specifically, the section defining portion 323 has a first extending portion 323a, a second extending portion 323b, and a connecting portion 323c. The first extending portion 323a is composed of a first groove portion 322a and a portion directly below the first groove portion 322a in the light guide member 320. The second extending portion 323b is composed of a second groove portion 322b and a portion directly below the second groove portion 322b in the light guide member 120. The coupling portion 323c is composed of a coupling groove portion 322c and a portion directly below the coupling groove portion 322c in the light guide member 120.

Further, the section defining portion 323 has a first portion 324 farthest from the center C and a second portion 325 closest to the center C.

The position P1 farthest from the center C in the partition defining portion 323 is located at the apex St of the corner of the light emitting region S of the other planar light source 300 adjacent in the diagonal direction W. Therefore, the first portion 324 is a portion including the farthest position P1 of the section defining portion 323 and having a thickness in a direction orthogonal to the diagonal directions W and Z directions.

The position P2 closest to the center C in the partition defining portion 323 is located on the outer peripheral edge of the light emitting region S and on a straight line parallel to the X direction (or Y direction) passing through the center C in a plan view. Therefore, the second portion 325 is a portion having a thickness in the Y direction, including the closest position P2 of the section defining portion 323.

The partition member 140 is provided, for example, in a portion of the first groove portion 322a excluding both ends in the Y direction and a portion of the second groove portion 322b excluding both ends in the X direction. The partition member 140 is not provided in the joint groove portion 322c. Therefore, the transparency of the first portion 324 is higher than that of the second portion 325.

Next, the effect of this modification will be described.
Similar to the first embodiment, in this modification as well, the transmittance of the first portion 324 is higher than the transmittance of the second portion 325. Therefore, it is possible to prevent the vicinity of the first portion of the light irradiation region of the planar light source 300 from being conspicuous as a dark portion.

Further, the side surface 326c of the coupling groove portion 322c connecting the side surface 326a of the groove 322 in the first extending portion 323a and the side surface 326b of the groove 322 in the second extending portion 323b is curved in a plan view. Therefore, the light emitted from the surface 326c is condensed. Therefore, it is possible to further suppress the vicinity of the connecting portion 323c from being conspicuous as a dark portion.

<Second embodiment>
Next, the second embodiment will be described.
FIG. 9 is a plan view showing a planar light source according to the present embodiment.
The planar light source 400 according to the present embodiment is different from the planar light source 100 according to the first embodiment in the configuration of the groove 422.

The upper surface 120a of the light guide member 120 is provided with a groove 422 that discontinuously surrounds the light source arrangement portion 121. The groove 422 has, for example, two first groove portions 422a extending in the Y direction and two second groove portions 422b extending in the X direction around one light source arrangement portion 121. No groove is provided between the Y-direction end of the first groove 422a and the X-direction end of the second groove 422b. That is, in the present embodiment, the light guide member 120 is not provided with the coupling groove portion 122c.

The upper surface 120a of the light guide member 120 is divided into a plurality of light emitting regions S by the groove 422. In the light emitting region S, the end faces of the two first groove portions 422a, the two second groove portions 422b, and the first groove portion 422a in the Y direction of the upper surface 120a are virtually extended in the Y direction to form the second groove portion 422b. This is a region surrounded by an extension portion 422c in which the end face in the X direction is virtually extended in the X direction and both intersect.

The section defining portion 423 includes a groove 422, a portion of the light guide member 120 located directly below the groove 422, and a portion of the light guide member 120 that overlaps with the extension portion 422c in a plan view. Further, the section defining portion 423 has a first portion 424 farthest from the center C and a second portion 425 closest to the center C.

The position P1 farthest from the center C in the partition defining portion 423 is located on the angle Sc of the light emitting region S of the other planar light source 100 adjacent in the diagonal direction. Therefore, the first portion 424 is a portion of the section defining portion 423 that includes the farthest position P1 and has a thickness in a direction orthogonal to the diagonal directions W and Z directions.

The position P2 closest to the center C in the partition defining portion 423 is located on the outer peripheral edge of the light emitting region S and on a straight line parallel to the X direction (or Y direction) passing through the center C in a plan view. Therefore, the second portion 425 is a portion of the section defining portion 423 that includes the closest position P2 and has a thickness in the Y direction.

The partition member 140 is filled in, for example, the first groove portion 422a and the second groove portion 422b. The groove 422 and the partition member 140 are not provided in the joint portion 423c. Therefore, the transmittance of the first portion 424 is higher than the transmittance of the second portion 425.

Next, the effect of this modification will be described.
In this modification, the groove 122 is not provided in the first portion 424. Therefore, it is possible to further suppress the vicinity of the first portion from being conspicuous as a dark portion.

<Third embodiment>
Next, a third embodiment will be described.
FIG. 10 is a plan view showing a planar light source according to the present embodiment.
FIG. 11 is an enlarged plan view showing a part of FIG. 10.
FIG. 12 is a cross-sectional view taken along the line 12-12 of FIG.
FIG. 13 is a cross-sectional view taken along the line 13-13 of FIG.
FIG. 14 is a cross-sectional view taken along the line 14-14 of FIG.
The planar light source 500 according to the present embodiment is different from the planar light source 100 according to the first embodiment in the configuration of the groove 522.

As shown in FIG. 10, the upper surface 120a of the light guide member 120 is provided with a groove 522 that continuously surrounds the light source arranging portion 121. The groove 522 combines, for example, two first groove portions 522a extending in the Y direction, two second groove portions 522b extending in the X direction, and a first groove portion 522a and a second groove portion 522b around one light source arrangement portion 121. It has four connecting groove portions 522c and the like.

As shown in FIG. 11, the width (dimension in the X direction) of the first groove portion 522a is maximum at a position where the position in the Y direction is the same as the position P2 closest to the light source 130, and at both ends in the Y direction. It is the minimum. Similarly, the width (dimension in the Y direction) of the second groove portion 522b is maximum at a position where the position in the X direction is the same as the position closest to the light source 130, and is minimum at both ends in the X direction.

As shown in FIG. 12, the depth of the groove 522 (dimension in the Z direction) is maximized in, for example, the first groove portion 522a or the second groove portion 522b. More specifically, the depth of the groove 522 becomes maximum at the center position of the first groove portion 522a in the Y direction or the center position of the second groove portion 522b in the X direction. Further, the depth of the groove 522 is minimized in, for example, the coupling groove portion 522c. More specifically, the depth of the groove 522 is minimized at the center position of the coupling groove portion 522c in the X direction or the Y direction. As described above, the width and depth of the groove 522 do not have to be constant. The width and depth of the groove 522 can be changed by adjusting, for example, the depth at which a cutting tool such as a tapered dicing saw is inserted into the light guide member 120.

In this way, when the depth of the groove 522 is different at each position in the X direction and each position in the Y direction, the wiring layer 111 in the wiring board 110 should avoid directly below the portion of the groove 522 where the depth is maximum. It may be provided. According to such a configuration, it is possible to prevent the wiring layer 111 from being damaged when the groove 522 is formed by a cutting tool such as a dicing saw.

As shown in FIG. 11, the section defining portion 523 includes a groove 522 and a portion of the light guide member 120 located directly below the groove 522. The section defining portion 523 has a first stretched portion 523a, a second stretched portion 523b, and a connecting portion 523c. The first extending portion 423a is composed of a first groove portion 522a and a portion directly below the first groove portion 522a in the light guide member 120. The second extending portion 523b includes a second groove portion 522b and a portion directly below the second groove portion 522b in the light guide member 120. The coupling portion 523c is composed of a coupling groove portion 522c and a portion directly below the coupling groove portion 522c.

Further, the section defining portion 523 has a first portion 524 farthest from the center C and a second portion 525 closest to the center C.

The position P1 farthest from the center C of the section defining portion 523 is located on the angle Sc of the light emitting region S of the other planar light source 500 adjacent in the diagonal direction W. Therefore, the first portion 524 is a portion of the section defining portion 523 that includes the farthest position P1 and has a thickness in the diagonal direction and in the direction orthogonal to the Z direction.

The position P2 closest to the center C in the section defining portion 523 is located on the outer peripheral edge of the light emitting region S and on a straight line parallel to the X direction (or Y direction) passing through the center C in a plan view. Therefore, the second portion 525 is a portion of the section defining portion 523 that includes the closest position P2 and has a thickness in the Y direction.

As shown in FIGS. 13 and 14, the depth of the groove 522 in the cross section of the first portion 524 is smaller than the depth of the groove 522 in the cross section of the second portion 525. The “depth of the groove 522 in the cross section of the first portion 524” refers to the maximum value d1 of the depth of the groove 522 in the cross section of the first portion 524 shown in FIG. The “depth of the groove 522 in the cross section of the second portion 525” refers to the maximum value d2 of the depth of the groove 522 in the cross section of the first portion 524 shown in FIG.
The “cross section of the first portion 524” means a cross section including the center C of the light source 130 and the farthest position P1 (cross section at line 13-13 in FIG. 11). The “cross section of the second portion 525” means a cross section including the center C of the light source 130 and the position P2 closest to the center C (cross section at line 14-14 in FIG. 11).

Further, as shown in FIGS. 13 and 14, the distance W1 between the opposite side surfaces of the groove 522 in the first portion 524 is smaller than the distance W2 between the opposite side surfaces of the groove 522 in the second portion 525. The "distance W1 between the opposite side surfaces of the groove 522 in the first portion 524" is a distance at which the distance between the opposite side surfaces of the groove 522 in the first portion 524 is maximized, as shown in FIG. The "distance W2 between the opposite side surfaces of the groove 522 in the second portion 525" is, as shown in FIG. 14, the distance at which the distance between the opposite side surfaces of the groove 522 in the second portion 525 is maximized. The distance means a distance in a direction orthogonal to the Z direction.

Therefore, the cross-sectional area of the groove 522 in the first portion 524 is smaller than the cross-sectional area of the groove 522 in the second portion 525. Therefore, for example, even if the first groove portion 522a, the second groove portion 522b, and the coupling groove portion 522c are filled with the partition member 140, the transmittance of the first portion 524 is higher than that of the second portion 525. The “cross-sectional area of the groove 522 in the first portion 524” means the area of the groove 522 in the cross section including the center C and the position P1 closest to the light source (cross section in lines 13-13 of FIG. 11). The “cross-sectional area of the groove 522 in the second portion 525” means the area of the groove 522 in the cross section including the center C and the position P2 closest to the light source (cross section in line 14-14 of FIG. 11).

Next, the effect of this embodiment will be described.
In the present embodiment, the depth of the groove 522 in the cross section of the first portion 524 is smaller than the depth of the groove 522 in the cross section of the second portion 525. Therefore, it is possible to prevent the vicinity of the first portion 524 from being conspicuous as a dark portion.

Further, the distance W1 between the opposite side surfaces of the groove 522 in the cross section of the first portion 524 is smaller than the distance W2 between the opposite side surfaces of the groove 522 in the cross section of the second portion 525. Therefore, it is possible to prevent the vicinity of the first portion 524 from being conspicuous as a dark portion.

Further, the cross-sectional area of the groove 522 in the first portion 524 is smaller than the cross-sectional area of the groove 522 in the second portion 525. Thereby, the transmittance of the first portion 524 can be made higher than the transmittance of the second portion 525.

In the above embodiment, both the width and the depth of the groove 522 are changed, but only the width may be changed or only the depth may be changed.

<Fourth Embodiment>
Next, a fourth embodiment will be described.
FIG. 15 is a plan view showing a planar light source according to the present embodiment.
FIG. 16 is a cross-sectional view taken along the line 16-16 of FIG.
The planar light source 600 according to the present embodiment is different from the planar light source 100 according to the first embodiment in that it does not include a partition defining portion.

As shown in FIG. 15, in the planar light source 600, a partition member 641 is provided so as to discontinuously surround the light source 130 mounted on the wiring board 110. As shown in FIG. 16, the partition member 641 is provided on, for example, the light-reflecting sheet 180, and is in contact with the light-reflective sheet 180.

As shown in FIG. 15, the partition member 641 has two first reflecting portions 641a extending in the Y direction and two second reflecting portions 641b extending in the X direction around one light source 130. The first reflecting portion 641a and the second reflecting portion 641b are separated from each other, and a partition member 641 is provided between the end portion of the first reflecting portion 641a in the Y direction and the end portion of the second reflecting portion 641b in the X direction. Not provided. Hereinafter, a portion surrounded by the first reflecting portion 641a adjacent to each other in the Y direction and the second reflecting portion 641b adjacent to each other in the X direction and not provided with the partition member 641 is also referred to as a “gap of the partition member 641”.

The partition member 641 is, for example, a resin containing a light-reflecting material. Specifically, as the partition member 641, a silicone resin containing titanium oxide, an epoxy resin, or the like can be used as the light-reflecting material.

As shown in FIGS. 15 and 16, the light guide member 620 is provided so as to cover the light source 130 and the partition member 641. The light guide member 620 is filled inside the outer peripheral portion 640 including the partition member 641 described later (that is, the region corresponding to the light emitting region S described later), and seals the light source 130. Further, the light guide member 620 is also filled in the gap of the partition member 641. Further, the light guide member 620 is provided directly above the partition member 641. However, the light guide member 620 may not be filled in the gap of the partition member 641 or may not be provided directly above the partition member 641.

Hereinafter, the frame-shaped portion including the partition member 641 and surrounding the light source 130 is referred to as an “outer peripheral portion 640”, and the region surrounded by the outer peripheral portion 640 is referred to as a “light emitting region S”. In this embodiment, the partition member 641 discontinuously surrounds the light source 130. Therefore, the outer peripheral portion 640 virtually extends the end faces of the first reflecting portion 641a, the second reflecting portion 641b, and the first reflecting portion 641a in the Y direction in the Y direction, and the second reflecting portion 641b is in the X direction. The end face is virtually extended in the X direction, and is composed of an extension portion 641c at which the two intersect. In the present embodiment, the extension portion 641c is filled with the light guide member 620.

Further, the outer peripheral portion 640 has a first portion 624 farthest from the center C and a second portion 625 closest to the center C.

The position P1 of the outer peripheral portion 640 farthest from the center C is located on the corner Sc of the extension portion 641c. Therefore, the first portion 624 is a portion of the outer peripheral portion 640 that includes the farthest position P1 and has a thickness in a direction orthogonal to the diagonal W and Z directions.

The position P2 closest to the center C in the outer peripheral portion 640 is on the surface of the first reflecting portion 641a in contact with the light guide member 620, and is on a straight line parallel to the X direction (or Y direction) passing through the center C in a plan view. Located in. Therefore, the second portion 625 is a portion of the outer peripheral portion 640 that includes the closest position P2 and has a thickness in the Y direction.

The first portion 624 is not provided with the partition member 641, whereas the second portion 625 is provided with the partition member 641. Therefore, the transmittance of the first portion 424 is higher than the transmittance of the second portion 625.

Next, the effect of this embodiment will be described.
The planar light source 600 according to the present embodiment includes a light source 130 and an outer peripheral portion 640 that surrounds the light source 130 and includes a partition member 641. The light source 130 is covered with a light guide member 620. In a plan view, the transmittance of the first portion 624 farthest from the center C of the light source 130 in the outer peripheral portion 640 is higher than the transmittance of the second portion 625 closest to the center C of the light source 130 in the outer peripheral portion 640. As a result, it is possible to prevent the vicinity of the first portion 624 of the light irradiation region of the planar light source 600 from being conspicuous as a dark portion. As a result, it is possible to realize a planar light source 600 that can suppress the dark portion from being conspicuous in the portion of the outer peripheral portion 640 farthest from the light source 130.

Further, in the outer peripheral portion 640, the partition member 641 is not provided in the first portion 624. Therefore, it is possible to prevent the vicinity of the first portion 624 from being conspicuous as a dark portion.

<Modified example of the fourth embodiment>
Next, a modified example of the fourth embodiment will be described.
FIG. 17 is a plan view showing a planar light source according to this modification.
FIG. 18A is a cross-sectional view taken along the line 18A-18A of FIG.
FIG. 18B is a cross-sectional view taken along the line 18B-18B of FIG.
The planar light source 700 according to the present embodiment is different from the planar light source 600 according to the fourth embodiment in the configuration of the partition member 741.

As shown in FIG. 16, in the planar light source 700, a partition member 741 surrounding the light source 130 is provided. A light guide member 620 is provided directly above the partition member 741. However, the light guide member 620 may not be provided directly above the partition member 741.

The partition member 741 includes a plurality of first reflecting portions 741a extending in the Y direction and in contact with the light guide member 620, a connecting portion 741c connecting adjacent first reflecting portions 741a in the Y direction, and a plurality of connecting portions 741c extending in the X direction. It has a second reflecting portion 741b.

As shown in FIG. 18A, the thickness (dimension in the Z direction) of the connecting portion 741c is smaller than the thickness of the first reflecting portion 741a. As shown in FIG. 18B, the second reflecting portion 741b is arranged, for example, between adjacent connecting portions 741c. The thickness of the connecting portion 741c is smaller than the thickness of the second reflecting portion 741b. The thickness of the first reflecting portion 741a is substantially the same as the thickness of the second reflecting portion 741b.

The partition member 741 is, for example, a resin containing a light-reflecting material. Specifically, as the partition member 741, a silicone resin containing titanium oxide, an epoxy resin, or the like can be used as the light-reflecting material.

As shown in FIG. 17, the outer peripheral portion 740 includes two first reflecting portions 741a, two second reflecting portions 641b, and four connecting portions 741c, and the end surface of the first reflecting portion 741a in the Y direction is Y. It is composed of an extension portion that virtually extends in the direction, virtually extends the end face of the second reflecting portion 741b in the X direction in the X direction, and intersects the two. In the present embodiment, the extension portion is provided with a connecting portion 741c and a light guide member 620.

Further, the outer peripheral portion 640 has a first portion 724 farthest from the center C and a second portion 725 closest to the center C.

The position P1 of the outer peripheral portion 740 farthest from the center C is located at the corner of the connecting portion 741c. Therefore, the first portion 724 is a portion including the farthest position P1 and having a thickness in the diagonal direction and the direction orthogonal to the Z direction.

The position P2 closest to the center C of the outer peripheral portion 740 is a straight line on the surface of the first reflecting portion 741a in contact with the light guide member 620 and parallel to the X direction (or Y direction) passing through the center C in a plan view. Located on top. Therefore, the second portion 725 is, for example, a portion of the outer peripheral portion 740 that includes the closest position P2 and has a thickness in the Y direction.

As described above, the thickness of the connecting portion 741c is smaller than the thickness of the first reflecting portion 741a and the thickness of the second reflecting portion 741b. Therefore, the thickness of the partition member 741 in the first portion 724 is smaller than the thickness of the partition member 741 in the second portion 725. Therefore, the cross-sectional area of the partition member 741 in the cross section including the center C and the farthest position P1 is smaller than the cross-sectional area of the section member 741 in the cross section including the center C and the nearest position P2. Therefore, the transmittance of the first portion 724 is higher than the transmittance of the second portion 725.

Next, the effect of this modification will be described.
In the planar light source 700 according to this modification, the thickness of the partition member 741 in the first portion 724 is smaller than the thickness of the partition member 741 in the second portion 725. As a result, it is possible to prevent the vicinity of the first portion 724 from being conspicuous as a dark portion.

Further, the cross-sectional area of the partition member 741 in the cross section including the center C and the farthest position P1 is smaller than the cross-sectional area of the section member 741 in the cross section including the center C and the closest position P2. As a result, the transmittance of the first portion 724 can be made higher than the transmittance of the second portion 725.

In the above-mentioned plurality of embodiments and modifications, an example in which the division defining portion or the outer peripheral portion has a grid pattern has been described. However, the partitioning portion or the outer peripheral portion does not have to be in a grid pattern. For example, the partition defining portion or the outer peripheral portion may be provided so that the light emitting region is a polygon other than a quadrangle such as a triangle or a hexagon.

The present invention can be used, for example, for a backlight.

100, 200, 300, 400, 500, 600, 700: Plane light source 110: Wiring substrate 110a: Top surface 110b: Bottom surface 111: Wiring layer 112, 113: Coating layer 114: Pad 120, 320, 620: Light guide member 120a : Upper surface 120b: Lower surface 121: Light source arrangement portion 122, 322, 422, 522: Groove 122a, 322a, 422a, 522a: First groove portion 122b, 322b, 422b, 522b: Second groove portion 122c, 322c, 522c: Coupling groove portion 123 , 323, 423, 523: Partition control part 123a, 323a, 423a, 523a: First extension part 123b, 323b, 423b, 523b: Second extension part 123c, 323c, 423c, 523c: Joint part 124, 324, 424, 524, 624, 724: 1st part 125, 325, 425, 525, 625, 725: 2nd part 126a, 126b, 226a, 226b, 326a, 326b: Side surface 126c, 226c: Bottom surface 130: Light source 131: Light emitting element 131a : Light source 131b, 131c: Electrode 132: Second light-transmitting member 133: Second light adjusting member 134: Coating member 135: Joining member 140, 240, 641, 741: Partition member 150: Light-reflecting member 160: No. 1 Light-transmitting member 170: First light adjusting member 180: Light-reflecting sheet 180a: Through hole 190: Adhesive sheet 190a: Through hole 241: First light-reflecting part 242: Second light-reflecting part 326c: Side surface of coupling groove part 422c: Extension 640, 740: Outer circumference 641a, 741a: First reflection 641b, 741b: Second reflection 641c: Extension 741c: Connection C: Light source center D1: First gap D2: Second gap K : Air layer L1, L1a, L1b, L1c, L2, L4, L5, LA, LB: Light S, S1, S2: Light source Sc: Angle St: Apex W: Diagonal d1: Groove in the cross section of the first part Depth d2: Depth of groove in the cross section of the second part W1: Distance between opposite sides of the groove in the cross section of the first part W2: Distance between opposite sides of the groove in the cross section of the second part

Claims (13)

Light source and
A light guide member having a light source arranging portion in which the light source is arranged and a partition defining portion including a groove surrounding the light source arranging portion.
A light-reflecting partition member arranged in the partition defining portion,
With
In a plan view, the transmittance of the first portion farthest from the center of the light source in the partition defining portion in the direction from the light source to the first portion is the second closest to the center of the light source in the partition defining portion. A planar light source having a higher transmittance than the part in the direction from the light source to the second part. The planar light source according to claim 1, wherein the cross-sectional area of the partition member in the first portion is smaller than the cross-sectional area of the partition member in the second portion. The planar light source according to claim 1 or 2, wherein the partition member is not provided in the first portion. The division regulation part
The first stretched portion extending in the first direction and
A second extending portion extending in the second direction intersecting the first direction,
A joint portion that connects the first stretched portion and the second stretched portion,
Have,
The first part is located at the joint and
The planar light source according to any one of claims 1 to 3, wherein the second portion is located in the first stretched portion or the second stretched portion. The planar light source according to claim 4, wherein the partition member is not provided in the joint portion. The surface according to claim 4 or 5, wherein the side surface of the groove in the joint portion connecting the side surface of the groove in the first stretched portion and the side surface of the groove in the second stretched portion is curved in a plan view. Light source. The planar light source according to any one of claims 1 to 6, wherein the depth of the groove in the cross section of the first portion is smaller than the depth of the groove in the cross section of the second portion. The method according to any one of claims 1 to 7, wherein the distance between the opposite side surfaces of the groove in the cross section of the first portion is smaller than the distance between the opposite side surfaces of the groove in the cross section of the second portion. Planar light source. The planar light source according to any one of claims 1 to 8, wherein the cross-sectional area of the groove in the first portion is smaller than the cross-sectional area of the groove in the second portion. The planar light source according to any one of claims 1 to 9, wherein the first portion is not provided with the groove. The groove of the section defining portion has a first side surface and a second side surface facing each other.
The partition member
A first light reflecting portion arranged with a plurality of first gaps provided on the first side surface,
A second light reflecting portion arranged with a plurality of second gaps provided on the second side surface,
Have,
The plurality of first gaps face the second light reflecting portion, and the plurality of first gaps face each other.
The planar light source according to any one of claims 1 to 10, wherein the plurality of second gaps face the first light reflecting portion. Light source and
An outer peripheral portion that surrounds the light source and has a light-reflecting partition member,
With
The light source is covered with a light guide member, and the light source is covered with a light guide member.
In a plan view, the transmittance of the first portion of the outer peripheral portion farthest from the center of the light source in the direction from the light source toward the first portion is the transmittance of the second portion of the outer peripheral portion closest to the center of the light source. , A planar light source having a higher transmittance in the direction from the light source to the second portion. The planar light source according to claim 12, wherein the partition member is not provided in the first portion of the outer peripheral portion.

Images