201007283 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，因此其需要借助背光模組 ©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。複數發光二極體14設置在框架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，在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 6 201007283 和第二擴散空間19’20之高度。然而，增加框架之深度將 減少出射光之焭度。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，而增大框架10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】 於上述狀'兄’有必要提供-種成本低且厚度較薄之 成光模組。 « ❹ 一^直下式背光模組，其包括—框架、複數發光二極 f、一擴散板及—光學板。複數發光二極體設置在框架之 =上’擴散板位於發光二極體上方，光學板間隔設置在 Ϊ =上二擴散板包括第一表面及與第-表面相對之 之第二表面，光學板3 及與第-表面相對 ❹ 之第表面為平面，擴散板包括形成於第二表面之沿至少 =同方向延伸之複數長條狀v型脊結構， 複型脊結構相互交錯。光學板包括形⑽第二= 行之長條狀弧形凸起，以及形成於第二表面之 伸方向鱼、條狀弧形凹槽’複數長條狀弧形凹槽延 β /、稷數長條狀弧形凸起之延伸方向相交。 鐾於上述情況，背光模組之擴散板包 面之沿至少二不同方向延伸之複數成：第-表 了光線在背光模組内之光程，增強光線之空口 加 有利於消除光源殘影。同時，光學板上之二::光 7 201007283 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，而不用藉由增加發光二極 體之數量及框架之深度之方式提升出射光之亮度及均勻 度，故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設置在框架22 之底板上。擴散板26設於框架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。光學板28與擴散板26間隔一定之距離，從而 形成一擴散空間31。 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。 請一併參見圖3，擴散板26由分散有散射粒子262之 透明材料製成。擴散板26包括第一表面264及與第一表面 264相對之第二表面266。第二表面266靠近複數發光二極 體24。 擴散板26之第一表面264為平滑表面。擴散板26在 第二表面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、 201007283 =方向X3延伸之複數第三¥型脊結構奶及沿第四方 延伸之複數第四v型脊結構274。上述v型脊結構相 -、VL^’曰{第二方向X2延伸之複數第二V型脊結構270與 ，一 方向乂4延伸之複數第四乂型脊結構272皆通過沿第 Ζ方向\延伸之第一 ν型脊結構⑽與沿第三方向&延 之第二V型脊結構272之間之交點。其中四方向U2、 .2及Χ4相鄰兩方向之間之夾角為45度。上述所有V型脊 ❹結構之豎直截面之頂角之取值範圍為8〇度至度，同方 =相鄰V型脊結構之間之中心距離可為G.G25毫米至土 宅米。本實施例中’四方向Χι、χ2、&及&相鄰v型脊 結構之間之中心距離分別為Di、A、D3與D4，且 DpDp如2=如4。此外，需要說明的是：藉由調整頂角之 大小，可在一定程度上調整擴散板26之增光率及出光視 角。第一、第二、第三、第四V型脊結構268、27〇、272、 274相互交錯，而形成複數三稜錐凹槽276，複數三稜錐凹 ❷槽276之間緊费相連，其中還有四相互連接之具有共同連 接點之三稜錐凹槽276及其相互連接之侧壁形成四角星形 278。複數四角星278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可由聚曱基丙烯酸曱酯、聚碳酸酯、聚笨乙烯、苯乙烯_ 曱基丙烯酸曱酯共聚物中之一種或一種以上之材料摻雜散 射粒子262後注塑成型而成。散射粒子262可為二氧化鈦 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。製備過程中需在模具上設置與三稜錐凹槽276 201007283 相應之凸起結構，以便使擴散板26可在單次注塑過程中成 型。可以理解，藉由調整散射粒子262與構成透明本體之 材料之間之比例可調節擴散板26之透過率，但將擴散板26 之透光率控制在80%以上為較佳選擇。 〇 請參見圖4至圖6,光學板28包括一透明本體，透明 本體包括第一表面282及與第一表面282相對之第二表面 284 ^第二表面284位於靠近複數發光二極體24之一側。 第一表面282形成有複數交替排佈且相互平行之長條狀ν 型凸起286及長條狀弧形凸起288。第二表面284形成有複 數相互平行之長條狀弧形凹槽29〇。複數長條狀ν型凸起 遍或長條狀弧形凸起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，複數長條狀ν型 ,起=或長條狀弧形凸起288之延伸方向與複數長條狀 弧形凹槽之延伸方向相互垂直。長條狀弧形凸起288 之垂直截面為半圓弧形，長條妝 ❹ 為半圓弧形。可以理解，==凹槽290之垂直截面 I條狀弧起288與長條狀弧 θ +直截面還可為橢圓弧形。 將長條狀v型凸起286之寬产 右^ α ^ 度記為Η!;則D、θ、Η滿足如又° ，頂角記為θ，高201007283 IX. Description of the Invention: [Technical Field] The present invention relates to a direct-lit backlight module, and more particularly to a direct-lit backlight module for 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 spaced apart between the light-emitting diodes 14 and the plurality of optical sheets 18 to divide the inside of the frame 10 into first and second diffusion spaces 19, 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 6 201007283 and the second diffusion space 19'20. However, increasing the depth of the frame will reduce the intensity of the outgoing light. If the number of the light-emitting diodes 14 is increased correspondingly, the production cost and the power consumption during use are increased, and increasing the depth of the frame 10 makes it difficult for the backlight module to meet the requirements of the thin design. " [Summary] It is necessary to provide a light-emitting module with low cost and thin thickness in the above-mentioned 'brother'. « ❹ A direct-lit backlight module, which includes a frame, a plurality of light-emitting diodes f, a diffuser plate, and an optical plate. The plurality of light emitting diodes are disposed on the frame=the upper diffusing plate is located above the light emitting diodes, and the optical plates are spaced apart from each other. The upper diffusing plate includes a first surface and a second surface opposite to the first surface, the optical plate 3 and the first surface opposite to the first surface is a plane, and the diffusion plate comprises a plurality of elongated v-shaped ridge structures formed on the second surface extending along at least = the same direction, and the complex ridge structures are interlaced. The optical plate comprises a strip-shaped arc-shaped protrusion of the shape (10) second=row, and a fish-shaped strip-shaped groove formed in the extending direction of the second surface, and a plurality of long strip-shaped curved grooves extending β/, the number of turns The extending directions of the elongated arcuate projections intersect. In the above case, the diffuser panel of the backlight module extends in at least two different directions: the first surface shows the optical path of the light in the backlight module, and the air-enhanced light is added to facilitate the elimination of the residual image of the light source. At the same time, the second layer on the optical plate:: light 7 201007283 line is further diffused and gathered in a specific viewing angle range, thereby forming a surface light source with high brightness and uniformity without increasing the number of light emitting diodes and The depth of the frame enhances the brightness and uniformity of the emitted light, so the backlight module of the present invention has a low cost and is suitable for a thin 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. The plurality of light emitting diodes 24 are disposed on the bottom plate of the frame 22. The diffuser plate 26 is disposed within 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. The optical plate 28 is spaced apart from the diffusion plate 26 by a certain distance to form a diffusion space 31. The frame 22 may be made of metal or plastic having high reflectivity or metal or plastic coated with a high reflectivity coating. 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 first surface 264 and a second surface 266 opposite the first surface 264. The second surface 266 is adjacent to the plurality of light emitting diodes 24. The first surface 264 of the diffuser panel 26 is a smooth surface. The diffusion plate 26 forms a plurality of first V-shaped ridge structures 268 extending in the first direction XiS on the second surface 266, a plurality of second V-shaped ridge structures 270 extending in the second direction X2, 201007283 = a plurality of third directions extending in the direction X3 The ridge structure milk and the plurality of fourth v-shaped ridge structures 274 extending along the fourth side. The v-shaped ridge structure phase-, VL^' 曰 {the second direction X2 extending the plurality of second V-shaped ridge structures 270 and the plurality of fourth ridge-type ridge structures 272 extending in one direction 乂4 are all along the second direction. The intersection of the first v-shaped ridge structure (10) extending and the second V-shaped ridge structure 272 extending in the third direction & The angle between the two directions U2, .2 and Χ4 in the four directions is 45 degrees. The apex angle of the vertical section of all the V-shaped ridge structures described above ranges from 8 degrees to degrees, and the center distance between the adjacent V-ridge structures can be G.G25 mm to the house-meter. In the present embodiment, the center distances between the four directions Χι, χ2, & and & adjacent v-ridge structures are Di, A, D3 and D4, respectively, and DpDp is 2 = 4, for example. In addition, it should be noted that the brightness enhancement and the exit angle of the diffuser plate 26 can be adjusted to some extent by adjusting the size of the apex angle. The first, second, third, and fourth V-shaped ridge structures 268, 27, 272, and 274 are interdigitated to form a plurality of triangular pyramid grooves 276, and the plurality of triangular pyramid recesses 276 are tightly charged. Connected, there are also four interconnected triangular pyramid grooves 276 having common joints and their interconnected side walls forming a four-pointed star 278. The plurality of four-pointed stars 278 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 doping the scattering particles 262 with one or more materials selected from the group consisting of polydecyl methacrylate, polycarbonate, polystyrene, and styrene-mercapto acrylate copolymer. The scattering particles 262 may be a mixture of one or more of titanium dioxide particles, cerium oxide particles, and acrylic resin particles. During the preparation process, a convex structure corresponding to the triangular pyramid groove 276 201007283 is provided on the mold so that the diffusion plate 26 can be formed in 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 constituting the transparent body, but it is preferable to control the light transmittance of the diffusing plate 26 to 80% or more. Referring to FIGS. 4-6, the optical plate 28 includes a transparent body including a first surface 282 and a second surface 284 opposite the first surface 282. The second surface 284 is located adjacent to the plurality of LEDs 24. One side. The first surface 282 is formed with a plurality of strip-shaped v-shaped projections 286 and elongated arc-shaped projections 288 which are alternately arranged and parallel to each other. The second surface 284 is formed with a plurality of elongated arcuate grooves 29 平行 which are parallel to each other. The plurality of elongated v-shaped projections extend in a direction in which the extending direction of the plurality of elongated arcuate projections intersects the extending direction of the plurality of elongated arcuate grooves 290. In this embodiment, the extending direction of the plurality of strip-shaped ν-shaped, up- or elongated arc-shaped projections 288 and the extending direction of the plurality of elongated arc-shaped grooves are perpendicular to each other. The long arc-shaped projection 288 has a semi-circular cross section and a long arc shape of a semi-circular shape. It can be understood that == vertical section of the groove 290. The strip-shaped arc 288 and the strip-shaped arc θ + the straight section can also be an elliptical arc. The wide yield of the long v-shaped protrusion 286 is recorded as Η!; then D, θ, Η satisfy as ° and the apex angle is θ, high
^毫米，⑽度…1〇〇度，〇 '隱5毫未=D 長條狀弧形凸起288之寬产^ 〜心毫米。將 米，2L ’ 0.01 · 〇.025 毫米咖.5 毫 之數值，可調。藉由調節D、e、札、 °長條狀V型凸起286及長條 201007283 從而調節光學板28之增光率及出 狀弧形凸起288之形狀， 光視角。 相鄰一長條狀狐形凹肖29〇之間距記為p，半n r’高度記為h1P、Qh滿足如下關係式：〇似毫米 f5毫米，p/4W2P’o.(n毫米㈣Γ。藉由調節p、 r及h之數值，可調整長條狀㈣凹槽謂之表面曲率及間 距，從而調節對複數長條狀弧形凹槽29〇對入射光之擴散 效果。 、 ❹ 光學板28之總體厚度可為〇·4毫米至4毫米。光學板 28可由聚甲基丙烯酸甲g|、聚碳酸自旨、聚笨乙婦、苯乙稀- 甲基丙烯酸甲醋共聚物中之一種或一種以上之材料注塑成 型而成。製備過程中需在模具上設置與長條狀¥型凸起· 和長條狀弧形凸起288相應之凹陷結構，以及與長條 形凹槽290之凸出結構，以便使光學板“可在單次注塑過 程中成型。 ❹ 光學板28採用注塑成型之方式一體成型，其上之長條 狀V型凸起286及長條狀弧形凸起288和光學板28之其他 部分一起形成，因此可使得長條狀v型凸起286及長條狀 弧形凸起288具有較高之結構強度，同時還能提升長條狀v 型凸起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 弧形凸起288在使用中被損壞之危險。光學板28具有將點 光源直接轉換為均勻分佈之面光源之作用。光學板之第 一表面282之長條狀V型凸起286可省略，而僅設置複數 11 201007283 相互平行之長條狀弧形凸起288,長條狀弧形凸起288之延 伸方向與第二表面284之複數長條狀弧形凹槽290之延伸 方向相互垂直。 ' 複數光學片30可為擴散片、增光片或反射式偏光片。 • 在直下式背光模組200中，擴散板26之第一表面264 靠近發光二極體24,其與發光二極體24頂部間之距離為小 於或等於3毫米。擴散板26可由支撐架支撐，或藉由粘接 之方式固定於框架22之内側壁上。光學板28間隔設置於 ®擴散板26之上方，在本實施例中，光學板28與擴散板26 之間之間距大於或等於10毫米。當然，二者間之距離可實 際情況作調整，一般地，在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一些。 使用時，可讓第二表面266靠近發光二極體作為入光 面而第一表面264遠離發光二極體作為出光面。由於擴散 板26本體内具有散射粒子262，且擴散板26之第二表面 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射出後與第·表面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31後，經過較 12 201007283 長之光程’從而增強紐之空間擴散效果，有利 源殘影。接著，光線射人光學板28，光學板28之声 284之長條狀弧形凹槽對光線發生一定程度之擴^妙 後經光學板28之第—表面282上之交錯排佈之長條狀μ 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，提升正面齐 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、平緩。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2〇0之擴散板％ 表面之微結構可有效增加光線在直下式背光模組2〇〇内之 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 ❹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，而不用藉由增 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’故直下式背光模組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：第二 表面466形成有沿三不同方向延伸之複數長條狀v型脊結 構’沿不同方向延伸之複數長條狀V型脊結構相互交錯。 13 201007283 其中沿一方向延伸之複數v型脊結構通過另外沿二不同方 向延伸並相交之複數v型脊結構之間之交點。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 ' 射出後與第一表面464之夾角較小。這樣，光線在框架22 内經過較長之光程，有利於增強空間擴散效果。 • 在實施例二中，擴散板46之第二表面466還可形成有 ♦ 沿二不同方向延伸之複數長條狀V型脊結構，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第一表面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垂直相交，從而將 長條狀弧形凸起486分隔為複數半圓柱狀凸起。第一表面 ❹482上之長條狀弧形凸起486之延伸方向與第二表面484 上之長條狀弧形凹槽490之延伸方向相交。具體在本實施 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之延伸方向與第二表 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 14 201007283 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。 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】 直下式背光模組 100、200 框架 10、22 反射板 12 發光二極體 14 擴散板 16 光學片 18 第一擴散空間 19 第二擴散空間 20 發光二極體 24 擴散板 26、46 散射粒子 262 第一表面 264 ' 464 第二表面 266、466 第一 V型脊結構 268 第二V型脊結構 270 第三V型脊結構 272 第四V型脊結構 274 三棱錐凹槽 276 四角星形 278 光學板 28、48 第一表面 282、482 第二表面 284 、 484 15 201007283 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 擴散空間 31^mm, (10) degrees...1 degree, 〇 'Hidden 5 毫==D Long strip-shaped curved protrusions 288 wide yield ^ ~ heart mm. The meter, 2L ’ 0.01 · 〇.025 mm coffee. 5 millimeters, can be adjusted. The optical viewing angle of the optical plate 28 and the shape of the arcuate projection 288 are adjusted by adjusting the D, e, Z, and the long strip-shaped V-shaped projections 286 and the strips 201007283. The distance between adjacent one-length foxes is 29, and the height of half-n r' is recorded as h1P, and Qh satisfies the following relationship: 毫米 mm f5 mm, p/4W2P'o. (n mm (four) Γ. By adjusting the values of p, r and h, the surface curvature and spacing of the long strips (four) grooves can be adjusted, thereby adjusting the diffusion effect of the complex strip-shaped arcuate grooves 29 on the incident light. ❹ Optical plate The overall thickness of 28 may be from 4 mm to 4 mm. The optical plate 28 may be one of polymethyl methacrylate, polycarbonate, polystyrene, styrene-methyl methacrylate copolymer. Or more than one type of material is injection-molded. In the preparation process, a concave structure corresponding to the long strip-shaped protrusions and the long strip-shaped convex protrusions 288 is disposed on the mold, and the elongated groove 290 is The structure is convex so that the optical plate can be formed in a single injection molding process. 光学 The optical plate 28 is integrally formed by injection molding, and the long V-shaped projections 286 and the elongated arc-shaped projections 288 thereon are formed. Formed together with other portions of the optical plate 28, thereby enabling the elongated v-shaped projections 286 and strips The shaped protrusions 288 have a higher structural strength, and at the same time, can enhance the bonding force of the long v-shaped protrusions 286 and the elongated curved protrusions 288 and other portions of the optical plate 28, thereby avoiding or reducing the strip shape. The v-shaped projections 286 and the elongated arcuate projections 288 are in danger of being damaged in use. The optical plate 28 has the function of converting the point source directly into a uniformly distributed surface source. The strip of the first surface 282 of the optical plate The V-shaped protrusions 286 can be omitted, and only the elliptical arc-shaped protrusions 288 which are parallel to each other in the plural number 11 201007283 are provided, and the extending direction of the elongated arc-shaped protrusions 288 and the plurality of long curved shapes of the second surface 284 The extending direction of the grooves 290 is perpendicular to each other. The plurality of optical sheets 30 may be a diffusion sheet, a brightness enhancement sheet or a reflective polarizer. • In the direct type backlight module 200, the first surface 264 of the diffusion plate 26 is adjacent to the light emitting diode. 24, the distance from the top of the light-emitting diode 24 is less than or equal to 3 mm. The diffuser plate 26 may be supported by the support frame or fixed to the inner side wall of the frame 22 by bonding. The optical plates 28 are spaced apart from each other. Above the diffusion plate 26, in this embodiment The distance between the optical plate 28 and the diffuser plate 26 is greater than or equal to 10 mm. Of course, the distance between the two can be adjusted in practice. Generally, the depth of the frame 22 and the light-emitting diode are the same when the uniformity of light output is the same. The number of the bodies 24 is inversely squared. 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 smaller, when the light-emitting diodes 24 are When the number is small, the depth of the frame 22 is large, and the distance between the optical plate 28 and the diffuser plate _ 26 is correspondingly set larger. In use, the second surface 266 can be made close to the light-emitting diode as the light-incident surface. A surface 264 is remote from the light emitting diode as a light exiting surface. Since the diffusion plate 26 has scattering particles 262 in the body, and the second surface 266 of the diffusion plate 26 is formed with a plurality of V-shaped ridge structures interlaced with each other, the light incident on the diffusion plate 26 can undergo specific refraction, scattering, reflection, diffraction, and the like. The optical action causes the light emitted from the diffusing plate 26 to be specifically diffused, and the angle of the light from the diffusing plate 26 to the surface 264 is small. Thus, the light enters the diffusion space 31 between the diffuser plate 26 and the optical plate 28, and after a longer optical path than the 12 201007283, the space diffusion effect of the New Zealand is enhanced, which is advantageous for the residual image. Then, the light is incident on the optical plate 28, and the long arc-shaped groove of the sound 284 of the optical plate 28 is extended to some extent by the staggered arrangement on the first surface 282 of the optical plate 28. The protrusions 286 and the elongated arc-shaped protrusions 288 have optical effects such as specific refraction, reflection and diffraction on the light emitted from the optical plate 28, so that the emitted light is further diffused and concentrated in a specific viewing angle range. Improve the front uniformity and form a uniform light source with uniform brightness. 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. It can be seen that the microstructure of the diffusing plate of the direct-type backlight module 2〇0 of the present invention can effectively increase the optical path of the light in the direct-type backlight module 2, so that the light is better dispersed, which is advantageous. In order to reduce the depth of the frame 22, the optical plate 28 then causes the emitted light to be further diffused and concentrated in a particularly wide range of viewing angles to form a surface light source having high brightness and uniformity. In this way, the light source image can be reduced or even avoided, without increasing the brightness and uniformity of the emitted light 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 lower. And suitable for thin design. Referring to FIG. 7, a diffusion plate 46 according to Embodiment 2 of the present invention is shown. The diffuser plate 46 has a similar structure to the diffuser plate 26, except that the second surface 466 is formed with a plurality of long strip-shaped V-shaped ridge structures extending in three different directions, and a plurality of long strip-shaped V-shaped ridge structures extending in different directions. Intertwined. 13 201007283 wherein a plurality of v-shaped ridge structures extending in one direction pass through intersections between a plurality of v-shaped ridge structures that additionally extend in two different directions and intersect. The apex angle of the plurality of long V-shaped ridge structures is 50 to 120 degrees. Similar to the diffuser plate 26, the diffusing plate 46 allows a specific diffusion of the emitted light, and the angle between the light emitted from the diffuser plate 46' and the first surface 464 is small. Thus, the light passes through the longer optical path within the frame 22, which is advantageous for enhancing the spatial diffusion effect. In the second embodiment, the second surface 466 of the diffuser plate 46 may be formed with a plurality of strip-shaped V-shaped ridge structures extending in two different directions, and the plurality of strip-shaped V-shaped ridge structures extending in different directions ® are mutually staggered. 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 first surface 482 of the optical plate 48 is formed with a plurality of elongated arcuate projections 486 which are parallel to each other and a plurality of elongated V-shaped projections 488 which are parallel to each other. . The plurality of elongated arcuate projections 486 intersect perpendicularly with the plurality of elongated V-shaped projections 488 to divide the elongated arcuate projections 486 into a plurality of semi-cylindrical projections. The direction in which the elongated arcuate projections 486 on the first surface ❹ 482 extend intersects the direction in which the elongated arcuate recesses 490 on the second surface 484 extend. Specifically, in the embodiment, the plurality of elongated arcuate protrusions 486 are perpendicular to the plurality of elongated V-shaped protrusions 488, and the extending direction of the plurality of elongated arcuate protrusions 486 is longer than the length of the second 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 over a specific 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 is only the preferred embodiment of the present invention 14 201007283, and it is not possible to limit the scope of the patent application in this case. 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. 3 is a perspective view of the diffusion plate of the backlight module shown in FIG. 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] Direct type backlight module 100, 200 Frame 10, 22 Reflector 12 Light-emitting diode 14 Diffusion plate 16 Optical sheet 18 First diffusion space 19 Second diffusion space 20 Light-emitting diode 24 Diffusion plate 26 , 46 scattering particles 262 first surface 264 464 second surface 266, 466 first V-shaped ridge structure 268 second V-shaped ridge structure 270 third V-shaped ridge structure 272 fourth V-shaped ridge structure 274 triangular pyramid groove 276 Four-pointed star 278 optical plate 28, 48 first surface 282, 482 second surface 284, 484 15 201007283 elongated V-shaped protrusion 286, 488 elongated arc-shaped protrusion 288, 486 long curved groove 290, 490 optical sheet 30 diffusion space 31
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