200846716 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】 由於液晶顯示器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。背光模組之作用是向液晶顯示器面板供應亮 l度充分且分佈均勻之面光源。 請參見圖1，所示為一種習知背光模組100,其包括框 架101、反射板102、擴散板103、稜鏡片104及至少一發 光二極體105。框架101包括一底板1011及複數從該底板 1011邊緣向其同一侧垂直延伸之侧壁1013。底板1011與 複數侧壁1013共同形成一腔體1017。發光二極體105包 括出光部1051與基部1053，基部1053與電路板（未標示） 相連並固定於底板1011。擴散板103與稜鏡片104依次設 置於複數侧壁1013頂部。反射板102為一小框體結構，其 可配置於框架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105之出 光部1051穿過相應通孔。發光二極體105之基部1053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102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 生一定程度之聚集，使得背光模組在特定視角範圍内之亮 6 200846716 度提1¾。 然，由於發光二極體1〇5為點光源，其到達擴散板1〇3 上各處之距離大小不相等，位於發光二極體1〇5正上方之 擴散板103單位區域所接受光較多，位於發光極管1〇5周 圍之擴散板103單位區域所接受光較少，因此容易在發光 二極體105正上方之區域形成亮區，而在其上方之周圍區 域形成暗區，影響背光模組100之出光均勻性。另，為達 到較好的光學均勻性，背光模組進中反射板皿與擴散 板103之間通常需留有較大的混光空間，故背光模組· 存在厚度較大之缺點。 通常，發光二極體105之上方還設置反射片1〇6，以 控制發光二極體1()5正上方之出光量。發光二極體1〇5與 反射片106之搭配設計，可在一定程度上減弱發光二極體 1〇5正上方之亮區，惟，f光模組⑽仍然存在 之缺點。 【發明内容】 雲於上述狀況’有必要提供一種出 及其光學板。 -種光學板’其包括至少—光學板單元 :包括第-表面及與該第一表面相對之第二表面先早 表面形成有複數微凸起，每一微凸起 ;:：： t側面’每一侧面之水平寬度沿遠離第一表 。該第二表面形成複數球面凹槽。該第_ ; 一表面之至少一表面開設有光源容納部。 乐 -種背光模組，其包括框架、擴散板、光學板及至少 7 200846716 側光式點光源；該框架包括底板及複數從該底板邊緣延 =之=互連接之側壁，該複數侧壁與該底板形成一腔體，· •一，有出光部之侧光式點光源設於該底板表面；該 κ政板封盍該腔體；該光學板設置於該腔體内，該光學板 匕括至少-光學板單元，該光學板單元包括第一表面及與 面㈣之第二表面’該第—表面形成有複數微凸 ，母二微凸起包括至少三個相互連接之侧面，每一侧面 ,平覓度遠離第一表面之方向逐漸縮小；該第二表面 形，複數球面凹槽；該第一表面和第二表面之至少一表面 開设有光源容納部；該側光式點光源之出光部相應設置于 該光源容納部内。 上述背光模組之光學板之光學板單元包括光源容納 部、與第一表面上之複數微凸起、以及第二表面形成之複 數球面凹槽，侧光式點光源之出光部容納在光源容納部， 從側光式點光源發出<光線通過光源容納部之内側壁直接 鲁進入光學板内部。由於微凸起具有變化之表面結構，使得 光線在光學板内傳輸至微凸起時，部分原先在未設有微凸 起之光學板内全反射之光線可被微凸起調節後朝向擴散板 方向折射出射，從而增加出射光線。進一步地，由於光學 板之第二面設置有球面凹槽，部分原先在未設有球面凹= 之光學板内全反射之光線可被其調節後從第二表面出射，9 反射後，此部分光線經多次折射後朝向擴散板均句出射。 ^，背光模組之光學均句性及光學利用率也將進一步提 冋更進v地•自於採用侧光式點光源，侧光式點光源 所發射之光線大部分於光學板内向四周傳播，在光學板之 8 200846716 瀵 作用下，點光源被轉變成面光源。故，採用該光學板之背 - 光模組中不需留有較大的混光空間，背光模組厚度較小。 .【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 學板作進一步詳細說明。 請參見圖2,所示為本發明較佳實施例一之背光模組 200，其包括一框架21、——反射板22、一擴散板23、一侧 光式點光源25、及一光學板20。框架21包括一長方形底 鲁板211及四個從底板211邊緣向其同一侧垂直延伸並相互 連接之侧壁213。四侧壁213與底板211共同形成一腔體 217。擴散板23設置於複數侧壁213頂部，用於封蓋腔體 217。腔體217用於收容光學板20、反射板22及侧光式點 光源25等元件。光學板20設置在腔體217内，其出光面 202面向擴散板23。光學板20底面203之下方設置有反射 板22。反射板22開設一對應於侧光式點光源25之通孔（未 標示），侧光式點光源25之出光部251穿過該通孔（未標 m W示）。侧光式點光源25固定於底板211。侧光式點光源25 優選為侧光式發光二極體，且其出光部251容納於光學板 20之光源容納部204内。本實施例中侧光式點光源25還 包括一設於頂部之反射元件253，該反射元件253可將從 侧光式點光源25之出光部251頂部發射出之部分光線反射 至光學板20内。從侧光式點光源25發出之光線於腔體217 内充分混合後可經過擴散板23出射。 請同時參見圖3至圖5，光學板20為矩形透明板，其 底面203中心開設有光源容納部204。光源容納部204為 9 200846716 從底面203貫穿至出光面2〇2之通孔。出光面2〇2形成有 -位於光源容納部2〇4周圍之複數微凸起。底面2⑽形 ,成有位於光源各納部204周圍之複數球面凹槽206。 本貝施例中，該複數微凸起205呈規則之陣列式排 佈，母一微凸起205為正四面錐形凸起，其中兩相對侧面 之夾角Θ1之較佳取值範圍為6〇至12〇度。如圖3所示， 複數微凸起205 與X軸方向& γ軸才目平行或垂直之方向 參延伸排列，相鄰微凸起2〇5之間距優選為〇·〇25毫米至2 耄米。另，複數微凸起205還可沿Χ軸與γ軸間之任意夾 角方向排列，此種排列可進一步控制出射光之出射角^。 可以理解，微凸起205之形狀並不限於正四面錐形凸起， 其也可為其他多面錐形凸起或錐台凸起。 少如圖5所不，本實施例中，該複數球面凹槽2〇6呈矩 /車歹j母凹槽206為半球面凹槽，相鄰球面凹槽2⑽ 之間距也優選為0·025毫米至2毫米。每一球面凹槽2抓 籲之半徑及深度之較佳取值範圍為〇 〇1毫米至2毫米。 、請再參閱圖2,在實施例一之背光模組2〇〇中'，側光 式，光源25之出光部251發射出之光線通過光源容納部 之内側壁直接進入光學板2〇内部。由於微凸起2仍具 有變，之表面結構，使得光線在光學板2Q内傳輸至凸起 吩，部分原來在未設有微凸起2〇5之光學板2〇内全反 射傳播之光線可被微凸起2〇5調節後沿特定之方向折射出 射’例如將部分光線調節至垂直於擴散板23方向之正面方 從而增加正面出射之光線，避免在相鄰之側光式 點先源25之間之上方產生暗區，提高背光模！且200之出光 200846716 均勻性。進一步地，由於光學板20之底面設置有球面凹槽 -206，部分原來在未設有球面凹槽206之光學板20内全反 _ 射傳播之光線可被其調節後從底面203出射，在框架101 之輔助作用下，此部分光線多次折射後朝向擴散板23出 射。故背光模組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，侧光式點光源25所 發射之光線大部分於光學板20内向周圍傳播，故點光源被 轉變成面光源。侧光式點光源25正上方之區域將避免出現 ® 亮點，此設計使得擴散板23與光學板20間距離之縮小成 為可能，從而，減小背光模組200之厚度。 可以理解，為使得該背光模組200在特定之視角範圍 内具有較高之亮度，在擴散板23之上方還可設置一棱鏡片 24 ;為使光束於腔體内均勻混光和提高光線利用率，該反 射板22可進一步包括複數貼於框架21侧壁213之反射側 壁 223。 另，本實施例之反射板22可省略，尤其當框架21為 *高反射材料製成或于底面塗覆反射塗層時。 請參見圖6,所示為本發明較佳實施例二之光學板 30。該光學板30與較佳實施例一之光學板20相似，其不 同在於光學板30之光源容納部304為從底面303向光學板 30内部凹陷之盲孔。 請參見圖7，所示為本發明較佳實施例三之光學板 40。該光學板40與較佳實施例二之光學板30相似，其不 同在於光學板40之微凸起405之頂角以及相鄰微凸起405 形成之底部夾角均被圓角化，分別形成圓角R1和R2。R1 11 200846716 % 和R2之圓角之取值範圍優選為大於0且小於或等於1.1 - 毫米。被圓角化之微凸起405可使出射光束之出射角度之 % 變化趨於缓和，使採用光學板40之背光模組之出光均勻性 提高。 請參見圖8,所示為本發明較佳實施例四組合光學板 50。該組合光學板50包括複數光學板單元52。光學板單 元52與較佳實施例一之光學板20之結構相同。複數光學 板單元52相互緊密排列，形成一較大之組合光學板50。 • 可以理解，上述本發明光學板單元之形狀可為多邊形 或圓形。光學板單元上之微凸起及球面凹槽之排佈方式包 括陣列排佈、陣列間隔排佈、隨機排佈或相對於光學板單 元之中心對稱分佈等，其中中心對稱排佈有利於光線在各 方向上均勻分散。 上述本發明光學板單元之球面凹槽還可通過改變其大 小及密度以調整光學板之出光面之光源均勻性。對於相同 大小之複數球面凹槽，可設置成等密度之排列；對於不同 ®大小之複數球面凹槽，距離光學板單元之中心較近處可設 置較小且密度較高之球面凹槽，而距離光學板單元之中心 較遠處可設置較大之且密度較低之球面凹槽。 請參見圖9，所示為本發明較佳實施例五之光學板 60，其與實施例二相似，不同在於光學板60之底面603 上之複數球面凹槽606為以光學板60之中心為圓心，沿著 圓環形軌道對稱分佈，越遠離該光學板60之中心，球面凹 槽606之直徑越大。 另，本發明光學板之微凸起和球面凹槽可互換設置於 12 200846716 出光面或底面’即在背光模组令，光源 述光學板之出光面及底面均可朝向 /為通孔之上 述，假設將本發明光學板之出光面或/==:上所 表面，與該其相對之底面或出光面定義 我為弟一 ::表面形成有複數微凸起’第二表面形成—二 綜上所述，本發明符合發明專利要件，爰依法 利申請。m所述者僅為本發明之較佳實施出^ 發明之範圍並不以上述實施方式為限，舉凡熟悉本 之人士，於爰依本案發明精神所作之等效 = 應包含於以下之申請專利範圍内。 心欠化，皆 【圖式簡單說明】 圖1係一種習知背光模組之剖示圖。 圖2係本發明較佳實施例一背光模組之剖示圖。 圖3係圖2所示背光模組之光學板之立體圖。 圖4係圖3所示光學板沿IV_IV線之剖示圖。 圖5係圖3所示光學板另一視角之立體圖。 圖6係本發明較佳實施例二光學板之剖示圖。 圖7係本發明較佳實施例三光學板之剖示圖。 圖8係本發明較佳實施例四組合光學板之立體分解 圖9係本發明較佳實施例五光學板之仰視圖。 【主要元件符號說明】 (本發明） 13 200846716 背光模組 ^ 框架 β 底板 侧壁 反射板 擴散板 侧光式點光源 出光部 ® 反射元件 (習知） 背光模組 框架 底板 側壁 Φ 腔體 反射板 光學板 20 出光面 202 底面 203 微凸起 205 球面凹槽 206 光源容納部 204 腔體 217 棱鏡片 24 反射侧壁 223 擴散板 103 稜鏡片 104 發光二極體 105 出光部 1051 基部 1053 反射片 106 14200846716 IX. Description of the invention: * [Technical field to which the invention pertains] 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 of the liquid crystal display panel itself does not have a light-emitting property, it is necessary to provide a light source device such as a backlight module to the liquid crystal display panel in order to achieve the 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 100 includes a frame 101, a reflector 102, a diffusion plate 103, a cymbal 104, and at least one light-emitting diode 105. The frame 101 includes a bottom plate 1011 and a plurality of side walls 1013 extending perpendicularly from the edge of the bottom plate 1011 toward the same side thereof. The bottom plate 1011 and the plurality of side walls 1013 together form a cavity 1017. The light-emitting diode 105 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 104 are sequentially disposed on top of the plurality of side walls 1013. The reflecting plate 102 is a small frame structure which can be 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 105 passes through the corresponding through hole. The base 1053 of the light emitting diode 105 holds the reflecting plate 102. During operation, the light generated by the LEDs 105 is reflected by the reflector 102 into the diffusion plate 103. After being uniformly diffused in the diffusion plate 103, the light continues to enter the cymbal 104. Under the action of the cymbal 104, the emitted light occurs to a certain extent. The gathering makes the backlight module brighter in the specific viewing angle range of 200846716. However, since the light-emitting diodes 1〇5 are point light sources, the distances reaching the diffusion plates 1〇3 are not equal, and the light received by the diffuser plate 103 directly above the light-emitting diodes 1〇5 is lighter. In many cases, the unit area of the diffusing plate 103 located around the light-emitting diode 1〇5 receives less light, so that it is easy to form a bright area in the area directly above the light-emitting diode 105, and a dark area is formed in the surrounding area above it. The light uniformity of the backlight module 100. In addition, in order to achieve better optical uniformity, a large light mixing space is usually required between the reflection plate and the diffusion plate 103 of the backlight module, so that the backlight module has the disadvantage of a large thickness. Usually, a reflection sheet 1〇6 is provided above the light-emitting diode 105 to control the amount of light emitted directly above the light-emitting diode 1()5. The design of the light-emitting diode 1〇5 and the reflection sheet 106 can weaken the bright area directly above the light-emitting diode 1〇5 to some extent, but the f-light module (10) still has the disadvantages. SUMMARY OF THE INVENTION It is necessary to provide a light source and its optical plate. - an optical plate comprising: at least - an optical plate unit comprising: a first surface and a second surface opposite the first surface; the first surface is formed with a plurality of microprotrusions, each microprotrusion;:: t side The horizontal width of each side is away from the first table. The second surface forms a plurality of spherical grooves. The at least one surface of the first surface is provided with a light source receiving portion. a backlight module comprising a frame, a diffusion plate, an optical plate and at least 7 200846716 edge-light point light source; the frame comprises a bottom plate and a plurality of sidewalls extending from the edge of the substrate = interconnecting the side walls The bottom plate forms a cavity, and the light-emitting point source having the light-emitting portion is disposed on the surface of the bottom plate; the κ-political plate seals the cavity; the optical plate is disposed in the cavity, and the optical plate is disposed in the cavity Including at least an optical plate unit, the optical plate unit including a first surface and a second surface of the surface (four), the first surface is formed with a plurality of micro-convex, and the second micro-protrusion includes at least three interconnected sides, each a side surface, the flatness is gradually narrowed away from the first surface; the second surface is shaped, a plurality of spherical grooves; at least one surface of the first surface and the second surface is provided with a light source receiving portion; the side light point light source The light exiting portion is correspondingly disposed in the light source housing portion. The optical plate unit of the optical plate of the backlight module includes a light source receiving portion, a plurality of micro-protrusions on the first surface, and a plurality of spherical grooves formed on the second surface, and the light-emitting portion of the edge-light point light source is accommodated in the light source. The light is emitted from the edge-light point source. The light passes directly through the inner side wall of the light source receiving portion into the interior of the optical plate. Since the micro-protrusions have a varying surface structure, when light is transmitted to the micro-protrusions in the optical plate, part of the light originally totally reflected in the optical plate not provided with the micro-protrusions can be adjusted by the micro-protrusions to face the diffusion plate. The direction is refracted to increase the outgoing light. Further, since the second surface of the optical plate is provided with a spherical groove, a portion of the light originally totally reflected in the optical plate not provided with the spherical concave = can be adjusted and emitted from the second surface, after the reflection, the portion After repeated refracting, the light is emitted toward the diffuser. ^, the optical uniformity and optical utilization of the backlight module will be further improved. • Since the edge-light point source is used, most of the light emitted by the edge-light point source propagates around the optical plate. Under the action of 8 200846716 光学, the point source is converted into a surface source. Therefore, the backlight module of the optical board does not need to have a large mixing space, and the backlight module has a small 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. Referring to FIG. 2, a backlight module 200 according to a preferred embodiment of the present invention includes a frame 21, a reflector 22, a diffuser panel 23, a side light point source 25, and an optical panel. 20. The frame 21 includes a rectangular base plate 211 and four side walls 213 extending perpendicularly from the edge of the bottom plate 211 toward the same side and interconnected. The four side walls 213 and the bottom plate 211 together form a cavity 217. A diffuser plate 23 is provided on top of the plurality of side walls 213 for covering the cavity 217. The cavity 217 is for accommodating components such as the optical plate 20, the reflecting plate 22, and the side-light point source 25. The optical plate 20 is disposed in the cavity 217 with its light exiting surface 202 facing the diffuser plate 23. A reflecting plate 22 is disposed below the bottom surface 203 of the optical plate 20. The reflector 22 defines a through hole (not shown) corresponding to the edge light source 25, and the light exit portion 251 of the edge light source 25 passes through the through hole (not shown). The edge light point source 25 is fixed to the bottom plate 211. The edge-light point light source 25 is preferably an edge-light type light-emitting diode, and the light-emitting portion 251 is housed in the light source housing portion 204 of the optical plate 20. In this embodiment, the edge-light point source 25 further includes a reflective element 253 disposed at the top, and the reflective element 253 can reflect a portion of the light emitted from the top of the light-emitting portion 251 of the edge-light point source 25 into the optical plate 20. . The light emitted from the edge-light point source 25 is sufficiently mixed in the cavity 217 to be emitted through the diffusion plate 23. Referring to FIG. 3 to FIG. 5 at the same time, the optical plate 20 is a rectangular transparent plate, and the bottom surface 203 is provided with a light source receiving portion 204 at the center. The light source housing portion 204 is a through hole that penetrates from the bottom surface 203 to the light exit surface 2〇2. The light-emitting surface 2〇2 is formed with a plurality of micro-protrusions located around the light source housing portion 2〇4. The bottom surface 2 (10) is shaped with a plurality of spherical grooves 206 located around the respective portions 204 of the light source. In the example of the present embodiment, the plurality of micro-protrusions 205 are arranged in a regular array, and the mother-micro-protrusions 205 are regular tetrahedral protrusions, and the angle between the two opposite sides is preferably 6〇. Up to 12 degrees. As shown in FIG. 3, the plurality of micro-protrusions 205 are arranged in parallel with the X-axis direction & γ-axis in parallel or perpendicular direction, and the distance between adjacent micro-protrusions 2〇5 is preferably 〇·〇 25 mm to 2 耄. Meter. In addition, the plurality of micro-protrusions 205 can also be arranged along any angular direction between the x-axis and the gamma axis, and the arrangement can further control the exit angle of the outgoing light. It will be appreciated that the shape of the microprotrusions 205 is not limited to regular tetrahedral projections, but may be other multifaceted conical projections or frustum projections. As shown in FIG. 5, in the embodiment, the plurality of spherical grooves 2〇6 are formed as a hemispherical groove, and the distance between adjacent spherical grooves 2(10) is also preferably 0·025. Mm to 2 mm. The radius and depth of each spherical groove 2 are preferably in the range of 〇 1 mm to 2 mm. Referring to FIG. 2, in the backlight module 2 of the first embodiment, the side light, the light emitted from the light exit portion 251 of the light source 25 directly enters the inside of the optical plate 2 through the inner side wall of the light source receiving portion. Since the micro-protrusions 2 still have a variable surface structure, the light is transmitted to the raised phenules in the optical plate 2Q, and the light that is originally totally reflected and propagated in the optical plate 2 without the micro-protrusions 2〇5 can be After being adjusted by the micro-protrusions 2〇5, it is refracted in a specific direction, for example, the partial light is adjusted to be perpendicular to the front side of the diffusion plate 23 to increase the light emitted from the front side, and avoid the adjacent side light source. A dark area is created between the top to improve the backlight mode! And 200 out of light 200846716 uniformity. Further, since the bottom surface of the optical plate 20 is provided with a spherical groove-206, a portion of the light originally transmitted in the optical plate 20 not provided with the spherical groove 206 can be adjusted and then emitted from the bottom surface 203. With the aid of the frame 101, this portion of the light is refracted multiple times and then exits toward the diffuser plate 23. Therefore, the optical utilization rate of the backlight module 200 will be further improved. Further, since the side-light point source 25 is used, most of the light emitted from the side-light point source 25 propagates around the optical panel 20, so that the point source is converted into a surface source. The area directly above the side-light point source 25 will avoid the occurrence of a ® bright spot. This design makes it possible to reduce the distance between the diffusion plate 23 and the optical plate 20, thereby reducing the thickness of the backlight module 200. It can be understood that in order to make the backlight module 200 have a high brightness in a specific viewing angle range, a prism sheet 24 may be disposed above the diffusion plate 23; in order to uniformly mix the light beam in the cavity and improve light utilization. The reflector 22 may further include a plurality of reflective sidewalls 223 attached to the sidewall 213 of the frame 21. Further, the reflecting plate 22 of the present embodiment can be omitted, especially when the frame 21 is made of a highly reflective material or a reflective coating is applied to the bottom surface. Referring to Figure 6, there is shown an optical plate 30 in accordance with a second preferred embodiment of the present invention. The optical plate 30 is similar to the optical plate 20 of the first embodiment except that the light source receiving portion 304 of the optical plate 30 is a blind hole that is recessed from the bottom surface 303 toward the inside of the optical plate 30. Referring to Figure 7, there is shown an optical plate 40 of a preferred embodiment of the present invention. The optical plate 40 is similar to the optical plate 30 of the second embodiment except that the apex angle of the micro protrusions 405 of the optical plate 40 and the bottom angle formed by the adjacent micro protrusions 405 are rounded to form a circle. Angles R1 and R2. The range of the rounded corners of R1 11 200846716 % and R2 is preferably greater than 0 and less than or equal to 1.1 mm. The rounded micro-protrusions 405 tend to moderate the change in the exit angle of the outgoing beam, thereby improving the uniformity of light output from the backlight module using the optical plate 40. Referring to Figure 8, there is shown a composite optical panel 50 of a preferred embodiment of the present invention. The combined optical plate 50 includes a plurality of optical plate units 52. The optical plate unit 52 has the same structure as the optical plate 20 of the preferred embodiment 1. The plurality of optical plate units 52 are closely arranged to each other to form a larger combined optical plate 50. • It will be understood that the shape of the optical plate unit of the present invention described above may be polygonal or circular. The arrangement of the micro-protrusions and the spherical grooves on the optical plate unit includes array arrangement, array spacing, random arrangement or symmetric distribution with respect to the center of the optical plate unit, wherein the central symmetric arrangement facilitates light The parties are evenly dispersed. The spherical groove of the above-described optical plate unit of the present invention can also adjust the light source uniformity of the light exiting surface of the optical plate by changing its size and density. For a plurality of spherical grooves of the same size, an arrangement of equal density can be set; for a plurality of spherical grooves of different sizes, a smaller and denser spherical groove can be disposed closer to the center of the optical plate unit, and A larger, lower density spherical groove can be provided at a distance from the center of the optical plate unit. Referring to FIG. 9, there is shown an optical plate 60 according to a fifth embodiment of the present invention, which is similar to the second embodiment except that the plurality of spherical grooves 606 on the bottom surface 603 of the optical plate 60 are at the center of the optical plate 60. The center of the circle is symmetrically distributed along the circular orbital track, and the further away from the center of the optical plate 60, the larger the diameter of the spherical groove 606. In addition, the micro-protrusions and the spherical recesses of the optical plate of the present invention are interchangeably disposed on the light-emitting surface or the bottom surface of the 12 200846716, that is, in the backlight module, the light-emitting surface and the bottom surface of the optical plate of the light source can be oriented toward/through the through hole. It is assumed that the surface of the optical plate of the present invention or the surface of the upper surface of the optical plate or the surface of the light-emitting surface is defined as the same as the surface: the surface is formed with a plurality of micro-protrusions, the second surface is formed - the second surface As described above, the present invention complies with the requirements of the invention patent, and is applied according to law. The above is only the preferred embodiment of the present invention. The scope of the invention is not limited to the above embodiments. For those who are familiar with the present invention, the equivalent of the invention according to the spirit of the present invention should be included in the following patent application. Within the scope. Heart simplification, both [Simplified illustration of the drawings] Figure 1 is a cross-sectional view of a conventional backlight module. 2 is a cross-sectional view of a backlight module in accordance with a preferred embodiment of the present invention. 3 is a perspective view of an optical plate of the backlight module shown in FIG. 2. Figure 4 is a cross-sectional view of the optical plate of Figure 3 taken along line IV_IV. Figure 5 is a perspective view of another view of the optical plate shown in Figure 3. Figure 6 is a cross-sectional view of an optical plate in accordance with a preferred embodiment of the present invention. Figure 7 is a cross-sectional view of a third optical plate in accordance with a preferred embodiment of the present invention. Figure 8 is a perspective exploded view of a four-part optical plate in accordance with a preferred embodiment of the present invention. Figure 9 is a bottom plan view of a fifth optical plate in accordance with a preferred embodiment of the present invention. [Main component symbol description] (Invention) 13 200846716 Backlight module ^ Frame β bottom plate side reflector diffuser side light point light source light exiting section —— Reflecting element (known) Backlight module frame bottom side wall Φ cavity reflector Optical plate 20 light-emitting surface 202 bottom surface 203 micro-protrusion 205 spherical groove 206 light source accommodating portion 204 cavity 217 prism sheet 24 reflection side wall 223 diffusion plate 103 104 104 light-emitting diode 105 light-emitting portion 1051 base 1053 reflection sheet 106 14