201007296 r 九、發明說明： .【發明所屬之技術領域】 本發明涉及一種直下式背光模組，尤其涉及一種應用 於液晶顯示之直下式背光模組。 【先前技術】 液晶顯示裝置被廣泛應用於個人數位助理、筆記型電 腦、數位相機、移動電話、液晶電視等電子產品中。但由 於液晶顯示裝置本身不能發光，是以需要借助背光模組才 ©能產生顯示功能。 請參見圖1，一種直下式背光模組100，其包括框架 10，一反射板12、複數發光二極體14、一擴散板16及複 數光學片18。該複數發光二極體14設置於框架10之底板 上，複數光學片18蓋設於框架10之開口處。擴散板16間 隔設置於發光二極體14及複數光學片18之間，從而將框 架10内分割成第一和第二擴散空間19、20。擴散板16由 含有散射粒子之樹脂材料製成。複數光學片18包括棱鏡 ®片、擴散片或折射偏振膜。 使用時，由複數發光二極體14產生之光線經過第一擴 散空間19後進入擴散板16，經過擴散板16擴散後，光線 進入第二擴散空間20進行擴散，最後經過複數光學片18 之擴散或聚集作用後，於特定視角範圍内均勻出射。 從發光二極體14發出之光線雖經過多次擴散，但仍很 難避免發光二極體14光源殘影之產生。為了儘量減少光源 殘影之產生，業界通常會增大框架10之深度，即增大第一 201007296 ^和第二擴散空間19’20之高度。惟，增加框架之深度將減 .少出射光之亮度。假如相應增加發光二極體14之數量，會 增加生產成本及使用時之消耗功率。而增大㈣1()之深度 將使背光模組難以滿足薄型化設計之要求。 【發明内容】 雲於上述狀況，有必要提供—種成本低且厚度較薄之 背光模組。 ❹—種直下式背光模組，其包括__框架、複數發光二極 體、-擴散板及-光學板。複數發光二極體設置於該框架 之底板上，擴散板設置於發光二極體上方’光學板間隔設 置於擴散板之上方。擴散板包括形成於出光面之沿至少二 不同方向延伸之複數長條狀¥型脊結構，不同方向延伸之 複數長條狀v型脊結構相互交錯。光學板包括形成於出光 面之複數相互平行之長條狀弧形凸起及形成於入光面之複 數相互平行之長條狀弧形凹槽，複數長條狀弧形凹槽延伸 ❹方向與複數長條狀弧形凸起之延伸方向相交。 上述背光模組之擴散板包括形成於出光面之沿至少二 不同方向延伸之複數V型脊結構，其可增加光線於背光模 、、内之光& ’增強S線之空間擴散效果，並可使光線於一 特定視角範圍内聚集，提升背光模組之正面出光率，從而 避免光源殘影之產生。同時，光學板上之微結構使出射光 f發f進—步擴散並向特定之視角範圍内聚集，進而形成 2度=均勻性較好之面光源’而不用藉由增加發光二極 之量及框架之深度之方式提升出射光之亮度及均勻 201007296 r 度，所以本發明之背光模組之成本較低，且適用於薄型化 - 設計。 【實施方式】 下面將結合附圖及實施例對本發明之背光模組作進一 步之詳細說明。 請參見圖2，本發明實施例一之直下式背光模組200 包括一框架22、複數發光二極體24、一擴散板26、一光學 板28及複數光學片30。複數發光二極體24設置於該框架 ® 22之底板上。擴散板26設置於框架22内並位於複數發光 二極體24之上方，光學板28及複數光學片30蓋設於框架 22之開口處，複數光學片30位於光學板28上方。光學板 28與擴散板26間隔一定距離，從而將框架22分割成第一 及第二擴散空間31、32。 框架22可由具有高反射率之金屬或塑膠製成，或塗佈 有高反射率塗層之金屬或塑膠製成。 φ 請一併參見圖3，擴散板26由分散有散射粒子262之 透明材質製成。擴散板26包括入光面264及與入光面264 相對之出光面266。出光面266靠近複數發光二極體24。 擴散板26之入光面264為平滑表面。該擴散板26於 出光面266形成沿第一方向XiS伸之複數第一 V型脊結構 268、沿第二方向X2延伸之複數第二V型脊結構270、沿 第三方向X3延伸之複數第三V型脊結構272及沿第四方向 X4延伸之複數第四V型脊結構274。上述V型脊結構相互 交錯。沿第二方向X2延伸之複數第二V型脊結構270與沿 8 201007296 弟四方向x4延伸之複數第四¥型脊結構272皆通過 ::延伸之第- V型脊結構268與沿第三 之弟三V型脊結構272之間之交點。其卜該四延丄申 Hi及x4中相鄰二方向之間之夾角為 :有乂型脊結構施、270、272、274《豎直戴面之頂= 取：範圍為80度至·度’同方向上相鄰V型脊結 =中心距離可為議5毫米幻毫米。本實施例中，四延伸 向I、Χ2、χ3及x4相鄰V型脊結構之間之中心間距分 別 D^、D2、D3 與 D4 ’ 。此外，需要說 =之係·藉由調整頂角之大小，可於—絲度上調整擴散 :26之增光率及出光視角。第一、第二、第三、第四V型 =構施、謂、272、274相互交錯，而形成複數三棱雜 凹槽276,複數三稜錐凹槽276之間緊密相連，其中還有四 相互連接之具有共同連接點之三稜錐凹槽W及其相 ❹ 接之側壁形成四角星形278。複數四角絲謂呈陣列排 佈。 擴散板26之總體厚度可為〇·4毫米至4毫米。擴散板 26可由聚甲基丙烯酸曱酯、聚碳酸醋、聚苯乙稀、苯乙烯 甲基丙烯酸甲S旨共聚物中之—種或—種以上之材料推雜散 射粒子262後注塑成型而成。散射粒？如可為二氧化欽 微粒、二氧化矽微粒和丙烯酸樹脂微粒中之一種或一種以 上之混合物。製備過程中需於模具上設置與三稜錐凹槽276 相應之凸起結構，以便使擴散板26可於單次注塑過程胃中成 型。可以理解，藉由調整散射粒子262與構成透明本體之 201007296 材質之間之比例可調節擴散板26之透過率，但將擴散板％ ' 之透光率控制於80%以上為較佳選擇。 請參見圖4至圖6，光學板28包括一透明本體，其包 括出光面282及與出光面282相對之入光面284。其中，出 光面282上形成有複數交替排佈且相互平行之長條狀乂型 凸起286及長條狀弧形凸起288;入光面2料上形成有複數 相互平行之長條狀弧形凹槽290。該複數長條狀v型凸起 286及長條狀弧形凸起288之延伸方向與複數長條狀弧形 凹槽290之延伸方向相交。本實施例中，該複數長條狀v 型凸起286及長條狀孤形凸起288之延伸方向與複數長條 狀弧形凹槽290之延伸方向相互垂直，該長條狀弧形凸起 之垂直戴面為半圓弧形，該長條狀藏形凹槽之垂直 戴面為半圓弧形。可以理解，長條狀弧形凸起观盘長條 狀弧形凹槽290之垂直截面還可為橢圓弧形。 ”八 將長條狀V型凸起286之寬度記為D，頂角記為θ，高 ©度記為Hl，則〇、θ、Ηι滿足如下關係式：0.025毫米<Dq 毫米，80 度 ^$100 度，〇〇1 w 〇 /m1 卡毫米。將長條 =形凸起288之寬度記為L，半徑記為R，高度記為h2, u 、r、h2滿足如下關係式：0 025 毫米， L/GR魏’ 0.01毫米碼。通過調節d、㊀、仏、l、 長條狀v型凸起286及長條狀弧 ^起8之形狀，從而調節光學板2〇之增光率及出光視 將相鄰二長條狀弧形凹槽29〇之間距記為p，半徑記為 201007296 Γ’高度記為h’貝1] Ρ、Γ及h滿足如下關係式：0.025亳米 ’ Ρ/κ^2ρ，〇·01 亳米 。通過調節 P、 d h之數值，可調整長條狀弧形凹槽290之表面ρ 距’從而調節職數長練__㈣以料 光學板28之總體厚度可為G.4毫米至4毫米。光 28可由聚甲基丙烯酸曱醋、聚碳酸醋、聚苯乙烯、 ❹^基丙烯酸甲g旨共聚物中之-種或—種以上之材質注塑成 里而成。製備過程中需於模具上設置與長條狀v型凸起挪 和長條狀弧形凸起288相應之凹陷結構，以及與長條狀弧 形凹槽290之凸出結構，以便使光學板28可於單次 程中成型。 光學板28採用注塑成型之方式一體成型，其上之 狀v型凸起286及長條狀弧形凸起和光學板28之其他 部分一起形成，是以可使得長條狀v型凸起286及長條狀 ❹弧形凸起288具有較高之結構強度，同時還能提升長條狀v =凸起286及長條狀弧形凸起288和光學板28其他部分之 結合力，從而可避免或減少長條狀v型凸起286及長條狀 ^形凸起288於使用中被損壞之危險。光學板28具有將點 發光二極體直接轉換為均勻分佈之面光源之優點。光學板 28之出光面282之長條狀v型凸起286可省略，而僅設置 、复數相互平行之長條狀紙形凸起288，長條狀弧形凸起％8 k伸方向與入光面284之複數長條狀弧形凹槽290之延 伸方向相互垂直。 11 201007296 ·' 複數光學片30可為擴散片、增光片或反射式偏光片。 - 於本實施例直下式背光模組200中，擴散板26設置於 框架22中部並可由支撐架支撐或通過黏接之方式固定於框 架22之内側壁上，光學板28蓋設於框架22之開口處。當 然，二者間之距離可視實際情況作調整，一般地，於出光 均勻度相同之情況下，框架22之深度與發光二極體24之 數量成反平方，當發光二極體24之數量較多時，框架22 之深度較小，光學板28與擴散板26間隔之距離可設置得 ®小一些，當發光二極體24之數量較少時，框架22之深度 較大，光學板28與擴散板26間隔之距離相應地設置得大 -—些 〇 使用時，發光二極體23發射出之光線經過第一空間31 擴散作用後進入擴散板26,由於擴散板26本體内具有散射 粒子262，且擴散板26之出光面266形成有複數相互交錯 之V型脊結構，射入擴散板26之光線可發生特定之折射、 @散射、反射與衍射等光學作用，從而可使從擴散板26出射 之光線發生特定之擴散，且光線自擴散板26射出後與出光 面264之爽角較小。這樣，光線進入擴散板26與光學板28 間之擴散空間32後，經過較長之光程，從而增強光線之空 間擴散效果，有利於消除光源殘影。接著，光線射入光學 板28，光學板28之入光面284之長條狀弧形凹槽290對光 線發生一定程度之擴散，然後經光學板28之出光面282上 之交錯排佈之長條狀V型凸起286及長條狀弧形凸起288, 對射出光學板28之光線發生特定之折射、反射與衍射等光 12 201007296 學作用，以使出射光線發生進一步擴散並向特定之視角範 - 圍内聚集，提升正面亮度並形成亮度均勻之面光源。 複數光學片30蓋設於光學板28上，可使出射光線更 為柔和、平缓。當然，當發光二極體24之間之間距較小時， 複數光學片30可省略。 由此可見，本發明之直下式背光模組200之擴散板26 表面之微結構可有效增加光線於直下式背光模組200内之 光程，使光線得到較佳之空間擴散，有利於減少框架22之 ®深度，然後，光學板28使出射光線發生進一步擴散並向特 定之視角範圍内聚集，從而形成亮度高且均勻性較好之面 光源。這樣，便可減弱甚至避免光源殘影，而不用通過增 加發光二極體24之數量及框架22之深度之方式提升出射 光之亮度及均勻度，所以直下式背光模組200之成本較低， 且適用於薄型化設計。 請參見圖7,所示為本發明較佳實施例二之擴散板46。 &擴散板46與擴散板26具有相似之結構，其不同在於：出 光面466形成有沿三不同方向延伸之複數長條狀V型脊結 構467、468、469，該沿不同方向延伸之複數長條狀V型 脊結構相互交錯。其中沿第一方向延伸之複數V型脊結構 467通過另外沿第二方向和第三方向延伸之複數V型脊結 構468、469之間之交點。複數長條狀V型脊結構之頂角為 50至120度。與擴散板26類似，擴散板46可使出射之光 線發生特定之擴散，光線自擴散板46射出後與入光面464 之夾角較小，這樣，光線於框架22内經過較長之光程，有 13 201007296 • 利於增強空間擴散效果。 •於本發明中，擴散板26之出光面266還可形成有沿二 不同方向延伸之複數長條狀V型脊結構，該沿不同方向延 伸之複數長條狀V型脊結構相互交錯。 請參見圖8，所示為本發明實施例三之光學板48。光 學板48與光學板28具有相似之結構，其不同在於：光學 板48出光面482形成有複數相互平行之長條狀弧形凸起 486和複數相互平行之長條狀V型凸起488。複數長條狀弧 ®形凸起486與複數長條狀V型凸起488相交。出光面482 上之長條狀弧形凸起486之延伸方向與入光面484上之長 條狀弧形凹槽490之延伸方向相交。具體於本實施例中， 複數長條狀弧形凸起486與複數長條狀V型凸起488相垂 直，且複數長條狀弧形凸起486之延伸方向與入光面484 上之長條狀弧形凹槽490之延伸方向相垂直。與光學板28 類似，光學板48可使光線發生進一步擴散並向特定之視角 &範圍内聚集。 綜上所述，本發明確已符合發明專利之要件，遂依法 提出專利申請。惟，以上所述者僅為本發明之較佳實施方 式，自不能以此限制本案之申請專利範圍。舉凡熟悉本案 技藝之人士援依本發明之精神所作之等效修飾或變化，皆 應涵蓋於以下申請專利範圍内。 【圖式簡單說明】 圖1係一種背光模組之剖面示意圖。 圖2係本發明實施例一之背光模組之剖面示意圖。 14 201007296 圖3係圖2所示背光模組之擴散板之立體圖。 圖4係圖2背光模組之光學板之立體圖。 圖5係圖4所示光學板V-V方向之剖視圖。 圖6係圖4所示光學板VI-VI方向之剖視圖。 圖7係本發明實施例二之擴散板之立體圖。 圖8係本發明實施例三之光學板之立體圖。 【主要元件符號說明】201007296 r IX. Invention Description: The present invention relates to a direct type backlight module, and more particularly to a direct type backlight module applied to a liquid crystal display. [Prior Art] Liquid crystal display devices are widely used in electronic products such as personal digital assistants, notebook computers, digital cameras, mobile phones, and LCD TVs. However, since the liquid crystal display device itself cannot emit light, it is necessary to use the backlight module to generate a display function. Referring to FIG. 1, a direct type backlight module 100 includes a frame 10, a reflecting plate 12, a plurality of light emitting diodes 14, a diffusing plate 16, and a plurality of optical sheets 18. The plurality of light-emitting diodes 14 are disposed on the bottom plate of the frame 10, and the plurality of optical sheets 18 are disposed at the openings of the frame 10. The diffusion plate 16 is interposed between the light-emitting diodes 14 and the plurality of optical sheets 18 to divide the inside of the frame 10 into the first and second diffusion spaces 19 and 20. The diffusion plate 16 is made of a resin material containing scattering particles. The plurality of optical sheets 18 include a prism sheet, a diffusion sheet or a refractive polarizing film. In use, the light generated by the plurality of light-emitting diodes 14 passes through the first diffusion space 19 and enters the diffusion plate 16. After being diffused by the diffusion plate 16, the light enters the second diffusion space 20 for diffusion, and finally passes through the diffusion of the plurality of optical sheets 18. Or after aggregating, it is uniformly emitted within a specific viewing angle range. Although the light emitted from the light-emitting diode 14 is diffused a plurality of times, it is still difficult to avoid the generation of the residual light of the light-emitting diode 14. In order to minimize the generation of residual light from the source, the industry generally increases the depth of the frame 10 by increasing the height of the first 201007296^ and the second diffusion space 19'20. However, increasing the depth of the frame will reduce the brightness of the emitted light. If the number of the light-emitting diodes 14 is increased correspondingly, the production cost and the power consumption during use are increased. Increasing the depth of (4) 1() will make it difficult for the backlight module to meet the requirements of a thin design. SUMMARY OF THE INVENTION In the above situation, it is necessary to provide a backlight module which is low in cost and thin in thickness. A direct-type backlight module includes a __frame, a plurality of light-emitting diodes, a diffusion plate, and an optical plate. The plurality of light emitting diodes are disposed on the bottom plate of the frame, and the diffusing plate is disposed above the light emitting diodes. The optical plates are spaced apart above the diffusing plate. The diffusing plate comprises a plurality of elongated strip-shaped ridge structures formed in the light exiting surface extending in at least two different directions, and the plurality of elongated v-shaped ridge structures extending in different directions are interlaced. The optical plate includes a plurality of long arc-shaped protrusions formed parallel to each other on the light-emitting surface, and a plurality of long-shaped arc-shaped grooves formed on the light-incident surface, the plurality of elongated arc-shaped grooves extending in the direction of the The extending directions of the plurality of elongated arcuate projections intersect. The diffusing plate of the backlight module includes a plurality of V-shaped ridge structures formed on the light-emitting surface extending in at least two different directions, which can increase the spatial diffusion effect of light on the backlight module, the light inside and the 'enhanced S-line, and The light can be concentrated in a specific viewing angle range, and the front light output rate of the backlight module is improved, thereby avoiding the generation of residual light of the light source. At the same time, the microstructure on the optical plate causes the emitted light f to be diffused and aggregated to a specific viewing angle range, thereby forming a surface light source of 2 degrees = uniformity without increasing the amount of light-emitting diodes. And the depth of the frame enhances the brightness of the emitted light and the uniformity of the 201007296 r, so the backlight module of the present invention has a low cost and is suitable for thinning-design. [Embodiment] Hereinafter, the backlight module of the present invention will be further described in detail with reference to the accompanying drawings and embodiments. Referring to FIG. 2, the direct type backlight module 200 of the first embodiment of the present invention includes a frame 22, a plurality of light emitting diodes 24, a diffusing plate 26, an optical plate 28, and a plurality of optical sheets 30. A plurality of light emitting diodes 24 are disposed on the bottom plate of the frame ® 22. The diffuser plate 26 is disposed in the frame 22 and above the plurality of light-emitting diodes 24. The optical plate 28 and the plurality of optical sheets 30 are disposed at the opening of the frame 22, and the plurality of optical sheets 30 are located above the optical plate 28. The optical plate 28 is spaced apart from the diffuser plate 26 to divide the frame 22 into first and second diffusion spaces 31, 32. The frame 22 may be made of metal or plastic having high reflectivity or metal or plastic coated with a high reflectivity coating. φ Referring to Fig. 3 together, the diffusion plate 26 is made of a transparent material in which scattering particles 262 are dispersed. The diffuser plate 26 includes a light incident surface 264 and a light exit surface 266 opposite to the light incident surface 264. The light-emitting surface 266 is adjacent to the plurality of light-emitting diodes 24. The light incident surface 264 of the diffuser plate 26 is a smooth surface. The diffusing plate 26 forms a plurality of first V-shaped ridge structures 268 extending in the first direction XiS, a plurality of second V-shaped ridge structures 270 extending in the second direction X2, and a plurality of third extending along the third direction X3 on the light-emitting surface 266. A V-shaped ridge structure 272 and a plurality of fourth V-shaped ridge structures 274 extending in the fourth direction X4. The above V-shaped ridge structures are interlaced with each other. The plurality of second V-shaped ridge structures 270 extending in the second direction X2 and the plurality of fourth-type ridge structures 272 extending along the fourth direction x4 of the 8 201007296 pass through: the extended V-shaped ridge structure 268 and the third The intersection of the three V-shaped ridge structures 272. The angle between the two adjacent directions of the four extensions Shen and x4 is: ridge type ridge structure application, 270, 272, 274 "top of vertical wear surface = take: range is 80 degrees to · degrees 'An adjacent V-shaped ridge knot in the same direction = center distance can be 5 mm imaginary millimeter. In this embodiment, the center distance between the adjacent V-shaped ridge structures extending from I, Χ2, χ3, and x4 is D^, D2, D3, and D4', respectively. In addition, it is necessary to say that = by adjusting the size of the apex angle, the diffusion can be adjusted on the silk: 26 brightness and light viewing angle. The first, second, third, fourth V-type = structure, said, 272, 274 are interdigitated to form a plurality of triangular-shaped recesses 276, and the plurality of triangular pyramid-shaped recesses 276 are closely connected, wherein There are also four interconnected triangular pyramid grooves W having common joints and their opposite side walls forming a quadrangular star 278. The multiple squares are arranged in an array. The diffuser plate 26 may have an overall thickness of from 4 mm to 4 mm. The diffusion plate 26 may be formed by injecting and scattering the scattering particles 262 from a polymethacrylate, a polycarbonate, a polystyrene, a styrene methacrylate or a copolymer of styrene methacrylate. . Scattering particles? For example, it may be a mixture of one or more of oxidized particles, cerium oxide particles and acrylic fine particles. During the preparation process, a convex structure corresponding to the triangular pyramid groove 276 is provided on the mold so that the diffusion plate 26 can be formed in the stomach of a single injection molding process. It can be understood that the transmittance of the diffusing plate 26 can be adjusted by adjusting the ratio between the scattering particles 262 and the material of the 201007296 constituting the transparent body. However, it is preferable to control the transmittance of the diffusing plate %' to 80% or more. Referring to Figures 4-6, the optical plate 28 includes a transparent body that includes a light exiting surface 282 and a light incident surface 284 opposite the light exiting surface 282. Wherein, the light-emitting surface 282 is formed with a plurality of long strip-shaped protrusions 286 and elongated arc-shaped protrusions 288 which are alternately arranged and parallel to each other; the light-incident surface 2 is formed with a plurality of long strips parallel to each other. Shaped groove 290. The extending direction of the plurality of elongated v-shaped projections 286 and the elongated arcuate projections 288 intersects the extending direction of the plurality of elongated arcuate grooves 290. In this embodiment, the extending direction of the plurality of elongated v-shaped protrusions 286 and the elongated elongated protrusions 288 is perpendicular to the extending direction of the plurality of elongated arcuate grooves 290, and the elongated arc-shaped convex The vertical wearing surface has a semicircular arc shape, and the vertical wearing surface of the long strip-shaped concave groove has a semicircular arc shape. It can be understood that the vertical cross section of the long arcuate convex shaped viewing plate elongated arcuate groove 290 may also be an elliptical arc. "The width of the strip-shaped V-shaped projection 286 is denoted by D, the apex angle is denoted by θ, and the high degree is denoted by H1, then 〇, θ, Ηι satisfy the following relationship: 0.025 mm < Dq mm, 80 degrees ^$100 degrees, 〇〇1 w 〇/m1 card mm. The width of the long strip = shaped protrusion 288 is denoted by L, the radius is denoted by R, the height is denoted by h2, and u, r, h2 satisfy the following relationship: 0 025 Mm, L/GR Wei '0.01 mm code. By adjusting the shape of d, one, 仏, l, long v-shaped protrusion 286 and long strip arc 8 to adjust the brightness of the optical plate 2 The distance between the adjacent two long strip-shaped curved grooves 29〇 is denoted by p, the radius is recorded as 201007296 Γ 'the height is recorded as h' shell 1] Ρ, Γ and h satisfy the following relationship: 0.025 亳米' Ρ /κ^2ρ,〇·01 亳米. By adjusting the values of P and dh, the surface ρ distance of the long arc-shaped groove 290 can be adjusted to adjust the total length of the __(4) to the overall thickness of the optical plate 28. It can be from G.4 mm to 4 mm. The light 28 can be injection molded from a variety of materials such as polymethyl methacrylate vinegar, polycarbonate, polystyrene, and styrene-based acrylic copolymer. In the preparation process, a concave structure corresponding to the long v-shaped convex projection and the long arc-shaped convex protrusion 288 is disposed on the mold, and the protruding structure with the long curved concave groove 290 is provided on the mold. In order to allow the optical plate 28 to be formed in a single pass. The optical plate 28 is integrally formed by injection molding, and the v-shaped projections 286 and the elongated arc-shaped projections thereon are combined with other portions of the optical plate 28. The formation is such that the long v-shaped protrusions 286 and the elongated curved protrusions 288 have a higher structural strength, and at the same time, the elongated strip v = protrusions 286 and the elongated arc-shaped protrusions can be raised. The bonding force between 288 and other portions of the optical plate 28 can avoid or reduce the risk of the long v-shaped protrusions 286 and the elongated shaped protrusions 288 being damaged in use. The optical plate 28 has a point-emitting light The pole body is directly converted into a uniform distributed surface light source. The long v-shaped protrusion 286 of the light-emitting surface 282 of the optical plate 28 can be omitted, and only the long strip-shaped paper-shaped protrusions 288 which are parallel to each other are arranged, and the strips are long. The extension of the arcuate projection %8 k and the extension of the plurality of elongated arcuate grooves 290 of the light incident surface 284 The directions are perpendicular to each other. 11 201007296 ·' The plurality of optical sheets 30 can be a diffusion sheet, a brightness enhancement sheet or a reflective polarizer. - In the direct type backlight module 200 of the present embodiment, the diffusion plate 26 is disposed in the middle of the frame 22 and can be supported by the support frame. Supported or fixed to the inner side wall of the frame 22 by means of bonding, the optical plate 28 is covered at the opening of the frame 22. Of course, the distance between the two can be adjusted according to the actual situation, generally, the uniformity of light emission is the same. In this case, the depth of the frame 22 is inversely squared from the number of the light-emitting diodes 24. When the number of the light-emitting diodes 24 is large, the depth of the frame 22 is small, and the distance between the optical plate 28 and the diffusion plate 26 can be set. When the number of the light-emitting diodes 24 is small, the depth of the frame 22 is large, and the distance between the optical plate 28 and the diffusion plate 26 is correspondingly set to be large - when used, the light-emitting diodes are used. The emitted light enters the diffusing plate 26 after being diffused through the first space 31. Since the diffusing plate 26 has scattering particles 262 in the body, and the light emitting surface 266 of the diffusing plate 26 is formed with a plurality of V-shaped ridge structures interlaced with each other. The light of the diffusing plate 26 can undergo specific optical effects such as refraction, @scattering, reflection, and diffraction, so that the light emitted from the diffusing plate 26 can be specifically diffused, and the light is emitted from the diffusing plate 26 and the light emitting surface 264 is cool. The angle is small. Thus, after the light enters the diffusion space 32 between the diffusing plate 26 and the optical plate 28, a long optical path is passed, thereby enhancing the spatial diffusion effect of the light, which is advantageous for eliminating the residual image of the light source. Then, the light is incident on the optical plate 28, and the long arc-shaped groove 290 of the light-incident surface 284 of the optical plate 28 diffuses the light to a certain extent, and then is staggered by the staggered arrangement on the light-emitting surface 282 of the optical plate 28. The strip-shaped V-shaped protrusions 286 and the elongated arc-shaped protrusions 288 have a specific effect of refracting, reflecting and diffracting the light emitted from the optical plate 28, so that the emitted light is further diffused and directed to a specific one. The angle of view - gathered inside, enhances the front brightness and forms a uniform surface light source. The plurality of optical sheets 30 are placed on the optical plate 28 to make the outgoing light softer and gentler. Of course, when the distance between the light-emitting diodes 24 is small, the plurality of optical sheets 30 can be omitted. Therefore, the microstructure of the surface of the diffusing plate 26 of the direct type backlight module 200 of the present invention can effectively increase the optical path of the light in the direct type backlight module 200, so that the light is diffused in a better space, which is beneficial to reducing the frame 22 The depth of the optical plate 28 then causes the emitted light to be further diffused and concentrated to a specific viewing angle range, thereby forming a surface light source having high brightness and uniformity. In this way, the light source afterimage can be weakened or even avoided, and the brightness and uniformity of the outgoing light are increased by increasing the number of the light emitting diodes 24 and the depth of the frame 22, so the cost of the direct type backlight module 200 is low. And suitable for thin design. Referring to FIG. 7, a diffusion plate 46 according to a second embodiment of the present invention is shown. The diffusion plate 46 has a similar structure to the diffusion plate 26, except that the light-emitting surface 466 is formed with a plurality of elongated V-shaped ridge structures 467, 468, 469 extending in three different directions, and the plurality of extending in different directions The long strip-shaped V-ridge structures are interlaced. The plurality of V-shaped ridge structures 467 extending in the first direction pass through intersections between the plurality of V-shaped ridge structures 468, 469 that extend in the second and third directions. The apex angle of the plurality of elongated V-shaped ridge structures is 50 to 120 degrees. Similar to the diffuser plate 26, the diffuser plate 46 can specifically diffuse the emitted light, and the angle between the light emitted from the diffuser plate 46 and the light incident surface 464 is small, so that the light passes through the optical path in the frame 22 for a long time. There are 13 201007296 • Conducive to enhancing the spatial diffusion effect. In the present invention, the light-emitting surface 266 of the diffuser plate 26 may be formed with a plurality of elongated V-shaped ridge structures extending in two different directions, and the plurality of elongated V-shaped ridge structures extending in different directions are interlaced with each other. Referring to FIG. 8, an optical plate 48 according to a third embodiment of the present invention is shown. The optical plate 48 has a similar structure to the optical plate 28, except that the light-emitting surface 482 of the optical plate 48 is formed with a plurality of elongated arc-shaped projections 486 which are parallel to each other and a plurality of elongated V-shaped projections 488 which are parallel to each other. A plurality of elongated arc-shaped protrusions 486 intersect the plurality of elongated strip-shaped V-shaped protrusions 488. The extending direction of the elongated arcuate projection 486 on the light exiting surface 482 intersects the extending direction of the elongated arcuate recess 490 on the light incident surface 484. Specifically, in the embodiment, the plurality of elongated arc-shaped protrusions 486 are perpendicular to the plurality of elongated V-shaped protrusions 488, and the extending direction of the plurality of elongated arc-shaped protrusions 486 is longer than the length of the light-incident surface 484. The direction in which the strip-shaped curved grooves 490 extend is perpendicular. Similar to the optical plate 28, the optical plate 48 allows the light to be further diffused and concentrated toward a particular viewing angle & In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the present invention are intended to be included within the scope of the following claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view of a backlight module. 2 is a cross-sectional view of a backlight module according to Embodiment 1 of the present invention. 14 201007296 Figure 3 is a perspective view of the diffuser plate of the backlight module shown in Figure 2. 4 is a perspective view of the optical plate of the backlight module of FIG. 2. Figure 5 is a cross-sectional view of the optical plate shown in Figure 4 in the V-V direction. Figure 6 is a cross-sectional view taken along line VI-VI of the optical plate shown in Figure 4. Figure 7 is a perspective view of a diffuser plate according to a second embodiment of the present invention. Figure 8 is a perspective view of an optical plate according to a third embodiment of the present invention. [Main component symbol description]
直下式背光模組 200 框架 22 發光二極體 24 擴散板 26 ' 46 散射粒子 262 入光面 264 ' 464 出光面 266> 466 第一 V型脊結構 268 、 467 第二V型脊結構 270、468 第三V型脊結構 272 、 469 第四V型脊結構 274 三棱錐凹槽 276 四角星形 278 光學板 28、48 出光面 282'482 入光面 284 ' 484 長條狀V型凸起 286'488 長條狀弧形凸起 288 、 486 長條狀弧形凹槽 290、490 光學片 30 第一擴散空間 31 第二擴散空間 32 15Direct type backlight module 200 Frame 22 Light-emitting diode 24 Diffusion plate 26' 46 Scattering particles 262 Light-incident surface 264 '464 Light-emitting surface 266> 466 First V-shaped ridge structure 268, 467 Second V-shaped ridge structure 270, 468 Third V-shaped ridge structure 272, 469 Fourth V-shaped ridge structure 274 Triangular pyramid groove 276 Square star 278 Optical plate 28, 48 Light-emitting surface 282'482 Light-incident surface 284 '484 Long-shaped V-shaped protrusion 286' 488 strip-shaped curved protrusions 288, 486 elongated arcuate grooves 290, 490 optical sheet 30 first diffusion space 31 second diffusion space 32 15