200844582200844582
I -九、發明說明： •【發明所屬之技術領域】 本發明涉及一種背光模組及其光學板，尤其涉及一種 用於液晶顯示之背光模組及其光學板。 【先前技術】 由於液a曰顯示|§面板之液晶本身不具發光特性，因而 為達到顯示效果需給液晶顯示器面板提供一面光源裝置， 如背光模組。背光模組之作用係向液晶顯示器面板供應亮 度充分且分佈均勻之面光源。 請參見圖1，所示為一種習知之背光模組1〇〇，其包括 框木101、反射板1〇2、擴散板103、稜鏡片1Q4及至少一 發光二極體105。框架101包括一底板ι〇11及複數從該底 板loii邊緣向其同一侧垂直延伸之侧壁1〇13。底板1〇11 與複數侧壁1013共同形成一腔體107。發光二極體1〇5包 括出光部1051與基部1053，基部1053與電路板(未標示） 馨相連並固定於底板1011。擴散板103與稜鏡片1〇4依次設 置於複數侧壁1013頂部。反射板102為一小框體結構，其 矸配置於框架101内部。反射板102之底部開設有與發光 二極體105相對應之通孔（未標示），發光二極體ι〇5之出 光部1051穿過相應通孔。發光二極體1〇5之基部頂 持該反射板102。 工作時，發光二極體105產生之光線被反射板1〇2反 射進入擴散板103 ’在擴散板103中被均勻擴散後光線繼 續進入稜鏡片104，在稜鏡片104之作用下，出射光線發 200844582 ^ .生：定程度之聚集，使得背光模組100在特定視角範圍内 . 之受度提南。 然而，由於發光二極體105為點光源，其到達擴散板 103上各處之距離大小不相等，位於發光二極體〗仍正上 方之擴散板103單位區域所接受光較多，位於發光極管 四周之擴散板103單位區域所接受光較少，因此容易在發 光一極體105正上方之區域形成亮區，而在其上方之四周 馨品或形成暗區’影響背光模組1〇〇之出光均勻性。為此， 通常需在發光二極體105之上方設置反射片106，以控制 毛光二極體105正上方之出光量。發光二極體1〇5與反射 片1〇6之搭配设计，可一定程度上減弱發光二極體正 上方之亮區，惟，背光模組100仍然存在出光不均之缺點。 【發明内容】 馨於上述狀況，有必要提供一種出光均勻之背光模組 及其光學板。 W 一光學板，其包括至少一光學板單元，該光學板單元 包括出光面、與該出光面相對之底面及形成於該出光面之 散射層，該底面形成有複數球形凹槽，且開設有至少—光 源容納部。 一背光模組，其包括框架、至少一側光式點先源、及光 學板；該框架包括底板及複數從該底板邊緣延伸之相互連 接之側壁，該複數侧壁與該底板形成一腔體；該至少〜 有出光部之點光源設於該底板表面；該光學板設置於兮_ 體内’該光學板包括至少一光學板單元，該光學板單元勺 6 200844582 · < _括出光面及與該出光面相對之底面，該底面形成有複數球 •形凹槽，且開設有至少一光源容納部；以及該光學板還包 括一形成於該出光面之散射層；該點光源之出光部相應設 置于該光源容納部内。 上述月光模組之光學板包括光源容納部、出光面形成 一散射層、底面形成複數球形凹槽以及點光源之出光部容 納在光源容納部。從點光源發出之光線通過光源容納部之 _内側壁直接進入光學板内部。由於光學才反之底面設置有球 ^凹杉，°卩分原來在未設有球形凹槽之光學板内全反射傳 播之光線可被其調節後從底面出射，在框架底板作用下， Ρ刀光線夕-人折射後進入散射層進行進一步散射，最後 «腔體開口均勻出射，因此背光模組之光學利用率可得到 進一步提高。由於採用側光式點光源，點光源所發射之光 線大部分於光學板内向四周傳播，點光源被轉變成面光 源。故，背光模組在採用較少之點光源數量情況下，可進 _行^低之燈箱咼度之設計；而且採用此具有散射層之導光 板之背光模組可省略習知擴散板之使用，從而背光模組可 以有效減少成本與降低厚度。 【實施方式】 下面將結合附圖及實施例對本發明之背光模組及其光 學板作進一步之詳細說明。 明芩見圖2，所不為本發明較佳實施例一之背光模組 200，其包括一框架21、一反射板22、一側光式點光源25 及塊光學板20。框架21包括一塊長方形底板211及四個 7 200844582 i - 從底板211邊緣向其同一侧垂直延伸並相互連接冬侧壁 . 213。四侧壁213與底板211共同形成一腔體217，用於收 容點光源25、反射板22及光學板20等元件。 請參見圖3，光學板20為與框架21之底板213相搭 配之矩形板，其包括一出光面202、一與出光面202相對 之底面203，以及一覆蓋出光面202之具有均勻厚度之散 射層204。底面203中央開設有一光源容納部205，而且底 面203形成複數圍繞光源容納部205之球形凹槽206。光 ® 源容納部205為從底面203向内凹陷之盲孔。該複數球形 凹槽206呈規則之陣列式排佈。每個球形凹槽206之球面 半徑R之取值範圍為0.01毫米至2毫米；每個球形凹槽206 之深度之取值範圍為大於0.01毫米且小於或等於其球面半 徑R。相鄰球形凹槽206之間距P之取值範圍為：R/2SP S4R。本實施例中，每個球形凹槽206為半球形凹槽。 散射層204由擴散油墨固化而成，其包括透明樹脂 φ 2042和均勻摻雜在透明樹脂2042中之散射粒子2044。透 明樹脂2042為擴散油墨中之清漆固化而成，優選丙烯酸樹 脂清漆。散射粒子2044以一定比例摻入擴散油墨中，其可 選自以下之一種或多種粒子：二氧化矽顆粒、聚曱基丙烯 酸曱酯顆粒和玻璃微珠等。 請再參閱圖2，侧光式點光源25優選為侧光式發光二 極體，其包括一基部253，一固定於基部253上方之出光 部251與一反射片255。點光源25通過電路板（圖未示） 固定於底板211。光學板20設置在腔體217内，其出光面 8 200844582 # . 202面向腔體217開口。點光源25之出光部251容納於光 學板20之光源容納部205内。反射片255設置在散射層 204對應點光源25正上方之位置，用於覆蓋點光源25之 頂部。反射片255之面積等於或略大於出光部251之投影 面積。反射板22開設有一對應于點光源25之出光部251 之通孔（未標示）。反射板22設置在光學板20底面203之 下方，點光源25之出光部251穿過該通孔（未標示）。 點光源25從出光部251發出之光線通過光源容納部 # 205之内侧壁直接進入光學板20内部。由於光學板20之 底面設置有球形凹槽206,部分原來在未設有球形凹槽2〇6 之光學板20内全反射傳播之光線可被其調節後從底面2〇3 出射，在反射板22之輔助作用下，此部分光線多次折射後 進入散射層204進一步散射，最後從腔體217開口均勻出 射。因此背光模組200之光學利用率也將進一步提高。更 進一步地，由於採用侧光式點光源25，點光源25所發射 之光線大部分於光學板2〇内向四周傳播，點光源被轉變成 9 面光源。因此，背光模組200在採用較少之點光源數量情 況下，可進行降低之燈箱高度之設計，從而背光模組2⑽ <以有效減少成本與降低厚度。 背光模組200還可包括一透明板（圖未示），用於封菩 腔體217之開口，也可另外增加一擴散板（圖未示）或 /棱鏡片（圖未示），用於提高該背光模組2〇〇在特定之視 角範圍内具有較高之均勻亮度。為使光束於腔體内均勻^ 光和提高光線利用率，該反射板22可進一步包括複數反身j 9 200844582 側另外需要強調：本實施例之反射板22可省略， 尤/、田框木21為高反射材料製成，或在底板211及/或側 土 213内側塗覆南反射塗層時。另外，本實施例中之光源 容納部巧可設計為貫穿出光面2〇2和底面期之通孔， /、二光原谷、、内部2〇5相搭配，點光源Μ之反射片可直 接設置於出光却9 ς 1 非點光源k必要=部。本實施例中之反射片255並 w 1 要兀件，側光式點光源25可採用其他減 等等7、、 射光束之其他設計，如於其頂部塗覆反射層 請參見圖4i 其區別僅在於光與柘 ^ 之月光杈組200相似， 散射層304為與光學板2〇不同。該光學板3〇之 點狀不規則^ 佈。本實施例中，散射層綱為網 4〇。=::广為本發明較佳實施例三之綱 九干板40與較佳實施例一之 僅在於光學板4()之底面4 ^于板20相似’其區別 實施例中，該複數球形畔條^凹槽概分佈*同。本 相互間緊密排佈。 Λ光源容納部·為中心， =見圖6,所示為本發明較佳實 5〇。光學板50與較佳實施例— 之光子板 僅在於光學板50之底面5〇3之^予板2〇相似，其區別 實施例中，該複數球形凹槽506 ^凹槽5〇6分佈不同。本 隨機分佈。 在光源容納部505之周圍 200844582 * - 球形凹槽分佈越密，採用該光學板之背光模組冬光學 ， 利用率越高。可以理解，本發明光學板之複數球形凹槽之 分佈並不限於上述實施例所述，例如，該複數球形凹槽呈 緊密之陣列排佈或間隔之陣列排佈。 上述實施例中，光學板20，30，40，50都為一整體結 構。本發明之大尺寸之光學板可由複數上述整體結構之光 學板單元組合而成，或者每個光學板單元開設複數光源容 納部。除了光學板20，30，40，50之形狀為矩形外，還可 為多邊形或圓形等。 本發明之光學板單元或組合光學板可設置複數光源容 納部，配合該複數光源容納部，可採用不同顏色之侧光式 發光二極體製成白光混光背光模組，或者採用相同顏色之 侧光式發光二極體製成特定顏色之背光模組。 上述實施例中光學板20，30之散射層204，304分佈 還可以有以下變換設計。 • 如圖7所示，散射層704在出光面702之分佈為：以 光源容納孔705為圓心，複數圓環狀之散射層704間隔分 佈，且越遠離光源容納孔705，圓環狀之散射層704之徑 向厚度越大，此設計有利於提高光學板之出光均勻性。 如圖8所示，散射層804在出光面802之分佈為：以 光源容納孔805為圓心，複數網點狀之散射層804沿著圓 環形轨道間隔分佈，且越遠離光源容納孔805，網點狀之 散射層804之直徑越大面積也越大，此設計有利於提高光 學板之出光均勻性。 11 200844582 如圖9所示，散射層904在出光面902之分佈為：以 光源容納孔905為圓心，複數相同大小之網點狀之散射層 904沿著圓環形轨道間隔分佈，且越遠離光源容納孔905， 網點狀之散射層904之排佈密度越大，此設計有利於提高 光學板之出光均勻性。 綜上所述，本發明確已符合發明專利要件，爰依法提 出專利申請。惟，以上所述者僅為本發明之較佳實施例， 舉凡热悉本案技蟄之人士，於援依本案發明精神所作之等 效修飾或變化，皆應包含於以下之申請專利範圍内。、 【圖式簡單說明】 圖1係一種習知之背光模組之結構示意圖。 圖2係本發明較佳實施例一之背光 圖。 面不意 圖3係圖2所示昔本措夕求庳_I-Nine, invention description: • Technical field of the invention The present invention relates to a backlight module and an optical plate thereof, and more particularly to a backlight module for liquid crystal display and an optical plate thereof. [Prior Art] Since the liquid crystal display does not have a light-emitting property, the liquid crystal display panel needs to provide a light source device such as a backlight module in order to achieve a display effect. The function of the backlight module is to supply a surface light source with sufficient brightness and uniform distribution to the liquid crystal display panel. Referring to FIG. 1, a conventional backlight module 1A includes a frame block 101, a reflector plate 2, a diffusion plate 103, a die 1Q4, and at least one light emitting diode 105. The frame 101 includes a bottom plate 11 and a plurality of side walls 1 〇 13 extending perpendicularly from the edge of the bottom plate to the same side. The bottom plate 1〇11 and the plurality of side walls 1013 together form a cavity 107. The light-emitting diode 1〇5 includes a light-emitting portion 1051 and a base portion 1053, and the base portion 1053 is connected to a circuit board (not shown) and fixed to the bottom plate 1011. The diffusion plate 103 and the cymbal sheet 1 are sequentially disposed on top of the plurality of side walls 1013. The reflecting plate 102 is a small frame structure, and the crucible is disposed inside the frame 101. A through hole (not shown) corresponding to the light emitting diode 105 is opened at the bottom of the reflecting plate 102, and the light emitting portion 1051 of the light emitting diode ι is passed through the corresponding through hole. The base of the light-emitting diode 1〇5 holds the reflecting plate 102. During operation, the light generated by the light-emitting diode 105 is reflected by the reflecting plate 1〇2 into the diffusing plate 103. After being uniformly diffused in the diffusing plate 103, the light continues to enter the cymbal 104, and the light is emitted by the cymbal 104. 200844582 ^. Health: a certain degree of aggregation, so that the backlight module 100 is within a certain range of viewing angles. However, since the light-emitting diode 105 is a point light source, the distances of the light-emitting diodes 103 reaching the diffusion plate 103 are not equal, and the unit of the diffusing plate 103 located directly above the light-emitting diodes receives more light, and is located at the light-emitting pole. The unit area of the diffusion plate 103 around the tube receives less light, so it is easy to form a bright area in the area directly above the light-emitting body 105, and the fragrant product or the dark area around the top of the tube affects the backlight module 1〇〇 Light uniformity. For this reason, it is usually necessary to provide a reflection sheet 106 above the light-emitting diode 105 to control the amount of light emitted directly above the light-emitting diode 105. The combination of the light-emitting diode 1〇5 and the reflective sheet 1〇6 can weaken the bright area directly above the light-emitting diode to some extent, but the backlight module 100 still has the disadvantage of uneven light output. SUMMARY OF THE INVENTION In the above situation, it is necessary to provide a backlight module with uniform light output and an optical plate thereof. An optical plate comprising at least one optical plate unit, the optical plate unit comprising a light emitting surface, a bottom surface opposite to the light emitting surface, and a scattering layer formed on the light emitting surface, wherein the bottom surface is formed with a plurality of spherical grooves and is opened At least - the light source housing. A backlight module includes a frame, at least one optical point source, and an optical plate; the frame includes a bottom plate and a plurality of interconnecting sidewalls extending from an edge of the bottom plate, the plurality of sidewalls forming a cavity with the bottom plate The at least ~ point light source having the light exit portion is disposed on the surface of the bottom plate; the optical plate is disposed in the body _ body. The optical plate includes at least one optical plate unit, and the optical plate unit spoon 6 200844582 · < _ And a bottom surface opposite to the light-emitting surface, the bottom surface is formed with a plurality of ball-shaped grooves, and at least one light source receiving portion is opened; and the optical plate further includes a scattering layer formed on the light-emitting surface; The portion is correspondingly disposed in the light source housing. The optical plate of the moonlight module includes a light source receiving portion, a light emitting surface forming a scattering layer, a bottom surface forming a plurality of spherical grooves, and a light emitting portion of the point light source being accommodated in the light source receiving portion. The light emitted from the point source directly enters the inside of the optical plate through the inner side wall of the light source housing. Since the optical surface is opposite to the bottom surface provided with the ball ^ cedar, the light that is totally reflected in the optical plate without the spherical groove can be adjusted and then emitted from the bottom surface, under the action of the frame bottom plate, the trowel light After the eclipse is refracted, it enters the scattering layer for further scattering. Finally, the cavity opening is evenly emitted, so the optical utilization of the backlight module can be further improved. Due to the use of the edge-light point source, most of the light emitted by the point source propagates around the optical plate, and the point source is converted into a surface source. Therefore, the backlight module can adopt the design of the light box with a small number of light sources, and the backlight module with the light guide plate of the scattering layer can omit the use of the conventional diffusion plate. Therefore, the backlight module can effectively reduce the cost and reduce the thickness. [Embodiment] Hereinafter, a backlight module and an optical plate thereof according to the present invention will be further described in detail with reference to the accompanying drawings and embodiments. 2 is a backlight module 200 according to a preferred embodiment of the present invention, which includes a frame 21, a reflector 22, a side light point source 25, and a block optical plate 20. The frame 21 includes a rectangular bottom plate 211 and four 7 200844582 i - extending from the edge of the bottom plate 211 to the same side and interconnecting the winter side walls 213. The four side walls 213 and the bottom plate 211 together form a cavity 217 for accommodating elements such as the point source 25, the reflecting plate 22, and the optical plate 20. Referring to FIG. 3, the optical plate 20 is a rectangular plate matched with the bottom plate 213 of the frame 21, and includes a light emitting surface 202, a bottom surface 203 opposite to the light emitting surface 202, and a scattering having a uniform thickness covering the light surface 202. Layer 204. A light source receiving portion 205 is defined in the center of the bottom surface 203, and the bottom surface 203 forms a plurality of spherical recesses 206 surrounding the light source receiving portion 205. The light source housing 205 is a blind hole that is recessed inward from the bottom surface 203. The plurality of spherical grooves 206 are arranged in a regular array. The spherical radius R of each of the spherical grooves 206 ranges from 0.01 mm to 2 mm; the depth of each of the spherical grooves 206 ranges from greater than 0.01 mm and less than or equal to its spherical radius R. The distance P between adjacent spherical grooves 206 ranges from R/2SP S4R. In this embodiment, each spherical groove 206 is a hemispherical groove. The scattering layer 204 is formed by curing a diffusion ink comprising a transparent resin φ 2042 and scattering particles 2044 uniformly doped in the transparent resin 2042. The transparent resin 2042 is formed by curing a varnish in a diffusing ink, preferably an acrylic resin varnish. The scattering particles 2044 are incorporated into the diffusion ink in a ratio which may be selected from one or more of the following particles: cerium oxide particles, polydecyl methacrylate particles, glass beads, and the like. Referring to FIG. 2, the edge-light point source 25 is preferably an edge-lit LED, and includes a base 253, a light-emitting portion 251 and a reflection sheet 255 fixed to the base 253. The point light source 25 is fixed to the bottom plate 211 through a circuit board (not shown). The optical plate 20 is disposed in the cavity 217, and its light exit surface 8 200844582 # . 202 faces the cavity 217 opening. The light exit portion 251 of the point light source 25 is housed in the light source housing portion 205 of the optical plate 20. The reflection sheet 255 is disposed at a position directly above the point source 15 of the scattering layer 204 for covering the top of the point source 25. The area of the reflection sheet 255 is equal to or slightly larger than the projection area of the light exit portion 251. The reflecting plate 22 defines a through hole (not shown) corresponding to the light exit portion 251 of the point source 25. The reflecting plate 22 is disposed below the bottom surface 203 of the optical plate 20, and the light exit portion 251 of the point light source 25 passes through the through hole (not shown). The light emitted from the light exit portion 251 by the point light source 25 directly enters the inside of the optical plate 20 through the inner side wall of the light source housing portion #205. Since the bottom surface of the optical plate 20 is provided with a spherical recess 206, a portion of the light that has been totally reflected and propagated in the optical plate 20 not provided with the spherical recess 2〇6 can be adjusted and then emitted from the bottom surface 2〇3, in the reflecting plate. Under the auxiliary action of 22, the portion of the light is refracted multiple times and then enters the scattering layer 204 to be further scattered, and finally uniformly emerges from the opening of the cavity 217. Therefore, the optical utilization of the backlight module 200 will be further improved. Further, since the edge light source 25 is used, most of the light emitted from the point source 25 propagates around the optical plate 2, and the point source is converted into a 9-side source. Therefore, the backlight module 200 can reduce the height of the light box when a small number of point sources are used, so that the backlight module 2 (10) <RTIgt; effectively reduces cost and thickness. The backlight module 200 may further include a transparent plate (not shown) for sealing the opening of the chamber 217, or an additional diffusion plate (not shown) or a prism sheet (not shown) for The backlight module 2 is improved to have a higher uniform brightness within a specific viewing angle range. In order to make the light beam uniform in the cavity and improve the light utilization rate, the reflector 22 may further include a plurality of reflexes. The side of the reflector is further emphasized. The reflector 22 of the embodiment may be omitted, in particular, the framed wood 21 Made of a highly reflective material, or coated with a south reflective coating on the inside of the bottom plate 211 and/or the side soil 213. In addition, the light source accommodating portion in the embodiment can be designed to penetrate through the light-emitting surface 2〇2 and the through-hole of the bottom surface, /, the two-light original valley, and the inner 2〇5, and the reflective sheet of the point light source can be directly set. In the light, it is 9 ς 1 non-point source k necessary = part. In this embodiment, the reflection sheet 255 and the w 1 are required to be used, and the edge-light point source 25 can adopt other design such as the reduction beam 7, etc., such as coating the reflective layer on the top thereof, please refer to FIG. 4i. It is only in the case that the light is similar to the moonlight group 200 of 柘^, and the scattering layer 304 is different from the optical plate 2〇. The optical plate 3 has a dot-like irregularity. In this embodiment, the scattering layer is a mesh. =:: is generally the third embodiment of the present invention. The dry plate 40 and the preferred embodiment 1 are only in the bottom surface 4 of the optical plate 4 (the same as the plate 20). In a different embodiment, the plurality of spheres The sidebars ^ grooves are roughly distributed * same. This is closely arranged with each other. The light source housing portion is centered, as shown in Fig. 6, which is a preferred embodiment of the present invention. The optical plate 50 is similar to the photonic plate of the preferred embodiment only in the bottom surface 5〇3 of the optical plate 50. In the different embodiments, the plurality of spherical grooves 506^the grooves 5〇6 are differently distributed. . This random distribution. Around the light source housing portion 505 200844582 * - The denser the spherical groove distribution, the higher the utilization rate of the backlight module using the optical plate. It will be understood that the distribution of the plurality of spherical grooves of the optical sheet of the present invention is not limited to that described in the above embodiments, for example, the plurality of spherical grooves are arranged in a tight array arrangement or an array of spaces. In the above embodiment, the optical plates 20, 30, 40, 50 are all of a unitary structure. The large-sized optical plate of the present invention may be composed of a plurality of optical plate units of the above-described overall structure, or a plurality of light source receiving portions may be provided for each of the optical plate units. In addition to the shape of the optical plates 20, 30, 40, 50 being rectangular, it may be polygonal or circular. The optical plate unit or the combined optical plate of the present invention may be provided with a plurality of light source accommodating portions, and the light source illuminating diodes of different colors may be used to form the white light mixed light backlight module, or the same color may be used. The edge-lit LEDs are made into a backlight module of a specific color. The distribution of the scattering layers 204, 304 of the optical plates 20, 30 in the above embodiment may also have the following conversion design. As shown in FIG. 7 , the distribution of the scattering layer 704 on the light-emitting surface 702 is as follows: the light source receiving hole 705 is centered, and the plurality of annular scattering layers 704 are spaced apart, and the farther away from the light source receiving hole 705, the circular scattering The greater the radial thickness of layer 704, this design is advantageous for improving the light uniformity of the optical plate. As shown in FIG. 8 , the distribution of the scattering layer 804 on the light-emitting surface 802 is as follows: the light source receiving holes 805 are centered, and the plurality of dot-like scattering layers 804 are spaced along the circular orbit, and the farther away from the light source receiving holes 805, the dots The larger the diameter of the scattering layer 804 is, the larger the area is. This design is advantageous for improving the light uniformity of the optical plate. 11 200844582 As shown in FIG. 9 , the distribution of the scattering layer 904 on the light-emitting surface 902 is: centered on the light source receiving hole 905 , and a plurality of dot-like scattering layers 904 of the same size are spaced along the circular orbit and are further away from the light source. The arrangement density of the receiving hole 905 and the dot-like scattering layer 904 is larger, and this design is advantageous for improving the light uniformity of the optical plate. In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. The above is only the preferred embodiment of the present invention, and those skilled in the art will be included in the following claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic structural view of a conventional backlight module. Figure 2 is a backlight view of a preferred embodiment of the present invention. Unsatisfactory Figure 3 is a picture of Figure 2
示意圖。 圖： 意圖。 圖7至圖9係本發明之光學板之散射層 之各種分佈 12 200844582schematic diagram. Figure: Intent. 7 to 9 are various distributions of scattering layers of the optical plate of the present invention 12 200844582
主要元件符號說明】 背光模組 200,300 光學板 20,30,40,50 框架 21 反射板 22 側光式點光源 25 出光面 202 底面 203,403,503 散射層 204,304 光源容納部 205,405,505 球形凹槽 206,406,506 底板 211 側壁 213 腔體 217 透明樹脂 2042 散射粒子 2044 基部 253 出光部 251 反射片 255 13Main component symbol description] Backlight module 200,300 Optical plate 20, 30, 40, 50 Frame 21 Reflector 22 Side light point light source 25 Light exit surface 202 Bottom surface 203, 403, 503 Scattering layer 204, 304 Light source receiving portion 205, 405, 505 Spherical groove 206, 406, 506 Base plate 211 Side wall 213 cavity Body 217 transparent resin 2042 scattering particles 2044 base 253 light exit portion 251 reflection sheet 255 13