201003236 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】 請參見圖1，所示為一種習知之直下式背光模組100， 其包括框架11與設置在該框架11内部之複數光源12、及設 置在光源12上方並蓋住框架11之擴散板13。 / 使用時，由複數光源12產生之光線進入擴散板13後被 擴散。然而，在經擴散板13擴散後，光線從擴散板13之出 射角度變得較為雜亂，使得其在特定視角範圍内之亮度不 高；並且由於光源12朝其正上方傳輸之光線較多，擴散板 13還是常常難以直接將來自光源12光線擴散均勻，使得從 擴散板13出射之光線容易產生光源殘影，即出現光強強弱 不同之區域。 f 為提高背光模組100在特定視角範圍内之亮度，以及避 免光源殘影之產生，從而提高背光模組100出射光之均勻 性，通常在擴散板13上方還設置有一光學板10與一上擴散 片14。如圖2所示，光學板10包括透明基板101及形成於透 明基板101上之稜鏡層103。棱鏡層103上具有複數長條形V 形凸起105。光學板10之長條形V形凸起105可使出射光線 發生一定程度之聚集，從而提高背光模組100在特定視角範 圍内之亮度。上擴散片14可對從光學板10出射之光線作進 一步擴散。 7 201003236 然而，光線在光學板10與上擴散片14中傳輸時，部分 光線會被吸收而造成光線損失；並且在光學板ig與: =14之間有空氣層’其會增加光線在傳㈣程中之介面二 量，增加光線傳輸之介面損失，降低光線利用率。 【發明内容】 馨於上述狀況’有必要提供一種可提高光線有效利用 率、出光均勻之背光模組及其光學板。 —種背光模組，其包括框架、光源及光學板，該 ^於該框架内，該光學板設置於該光源上方， 由、 透明本體構成，其包括第一表面及與該第_表面相對= =，該透明本體之第一表面為平面，該第二表面具有 複相互平仃之長條狀弧形凸起及複數相互 …延伸方向和該長條狀$ 一表=::表其::;=面，趙包括第 第一表面，該透明本體之第 、，·w面，該第二表面具有複數相互平行之長停狀弧 形凸起及複數相互平行之長條狀v形凸起，且該長 形凸起之延伸方向和該長條狀V形凸起之延伸方向相交。 妒凸==組中之光學板由於第二表面上之長條狀弧 ^ ^伸方向和長條狀乂形凸起之延伸方向相交，從 互父錯構成變化之曲面結構，其有利於讓射入光學板 :光線發生特定之折射、反射與衍射等光學作用，=反 使從光學板出射之光線在一特定之視角範圍聚集，與此同 201003236 時，還可使光線發生擴散，以減弱甚至避免光源殘影，提 尚背光模組之出光均勻性，避免了採用上擴散片而產生之 .介面損失，提升光線利用率。 【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。 請參見圖3至圖6，所示為本發明較佳實施例一之光學 板20,其由一透明本體構成，該透明本體包括第一表面 及與第一表面201相對之第二表面2〇3。第一表面2〇1為平 面，第二表面203具有複數相互平行之長條狀弧形凸起2〇4 和複數相互平行之長條狀V形凸起2〇5，複數長條狀弧形凸 起204之延伸方向和複數長條狀v形凸起2〇5之延伸方向相 交。本實施例中，複數長條狀弧形凸起2〇4之延伸方向和複 數長條狀V形凸起205之延伸方向相互垂直，且該長條狀弧 形凸起204之截面為半圓弧形。將相鄰兩長條狀弧形凸起 v 204之中心間距記為p，半徑記為R ;將相鄰兩長條狀v形凸 起205之中心間距記為Pi ;將長條狀弧形凸起2〇4和該長條 狀V形凸起205之高度記為η，則p、R、Pl&H滿足如下關 係式.0.025 毫米 SPS1.5 毫米，p/4‘Rg2P，0.025 毫米 $ Pi S 1毫米，〇.〇1毫米SHgR。換而言之相鄰兩柱形凸 起204之中心間距P可為〇.〇25毫米至ι.5毫米，半徑R可為 0-006毫米至3毫米，相鄰兩長條狀v形凸起2〇5之中心間距 ρι可為0.025毫米至1毫米，及長條狀弧形凸起2〇4和長條狀 V形凸起205之尚度Η可為〇.〇1毫米至3毫米。此外，該長條 9 201003236 狀V形凸起205之頂角Θ為80度至100度。另，藉由調整長條 狀V形凸起205之頂角Θ之大小，可在一定程上調整光學板 20之增光率及出光視角。 光學板20之總體厚度Τ可為0.4毫米至4毫米。光學板20 ‘可由聚甲基丙烯酸曱酯、聚碳酸酯、聚苯乙烯、苯乙烯-曱基丙烯酸甲酯共聚物中之一種或一種以上之材質注塑成 型而成。製備過程中需在模具上設置與長條狀弧形凸起204 以及長條狀V形凸起205相應之凹陷結構，以便使光學板20 可在單次注塑過程中成型。 光學板20採用注塑成型之方式一體成型，其上之長條 狀弧形凸起204及長條狀V形凸起205和光學板20之其他部 分一起形成，是以可使得長條狀孤形凸起204以及長條狀V 形凸起205具有較高之結構強度，同時還能提升長條狀弧形 凸起204以及長條狀V形凸起205和光學板20其他部分之結 合力，從而可避免或減少長條狀弧形凸起204以及長條狀V 形凸起205在使用中被損壞之危險。 為進一步驗證光學板20可對入射其中之光線起特定之 擴散作用，特別選取如表1所列之樣品進行對比測試，其結 果如圖7至圖9所示。 表1測試樣品 樣品號 樣品組成 1 發光二極體 2 發光二極體+光學板10 3 發光二極體+光學板20 10 201003236 分析圖7、圖8與圖9所示結果’發光二極體發出之光為 一中心強度高之亮點；從光學板1〇中出射之光線會形成兩 中心強度高之亮點；而從光學板20出射之光線則擴散成兩 條長度較長且亮度較均勻之光線帶。由此可見，光學板 具備產生虛擬光源和產生光線帶之優點。 請參閱圖10，所示為本發明較佳實施例二之光學板 30。光學板30與較佳實施例一之光學板2〇相似，第一表面 301為平面。其不同在於：第二表面3〇3之長條狀弧形凸起 304之截面為半橢圓形。當然，長條狀弧形凸起3〇4之截面 還可為漸擴形曲面等其他形狀。 請參見圖11，所示為本發明較佳實施例三之背光模組 200，其包括上述光學板2〇、框架21及光源22，該光源^ 位於該框架21内，該光學板2〇設置於該光源22上方。 框架21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。 C 光源22可為線光源或點光源，例如冷陰極螢光燈與發 光二極體，本實施例中為冷陰極螢光燈，該冷陰極螢光燈 之間較為緊密排佈，且該冷陰極螢光燈之延伸方向與光學 板20第二表面203上之長條狀v形凸起2〇5或長條狀弧形2 起204之延伸方向相同。 上述背光模組200中之光學板2〇之第一表面2〇1靠近光 源而第二表面203遠離光源22。自於第二表面2〇3之長條狀 弧形凸起204之延伸方向和長條狀v形凸起2〇5之延伸方向 相互垂直，從而相互交錯構成變化之曲面結構；同時，複 11 201003236 數冷陰極螢光燈緊密排佈，且該複數冷陰極營光燈之延伸 方向和光學板20第二表面203上之長條狀v形凸起2〇5或長 條狀弧形凸起204之延伸方向相同，是以有利於讓射入光學 板20之光線發生特定之折射、反射與衍射等光學作用，進 而可使從光學板20出射之光線發生特定之擴散，從而形成 亮度較均句之光亮面。由此可見，上述背光模組可以減 弱甚至避免光源殘影，提咼背光模組之出光均勻性，避免 了採用上擴散片而產生之介面損失，提升光線利用率。當 然，當光源22為點光源時，將點光源緊密排佈成陣列，可 同樣達到使用線光源之效果。 可以理解，當光源22之間的間距較大時，可於本發明 之背光模組200之光學板20和光源22之間增設一擴散板，從 而可進一步將光線擴散均勻，提升背光模組之出光均勻性。 可以理解’光學板20由於具有較好之光擴散功能，可 作為光擴散板使用。 ( 綜上所述，本發明確已符合發明專利要件，查依法提 出專利申請。惟，以上所述者僅為本發明之較佳實施例， 舉凡熟悉本案技藝之人士，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剖面示意圖。 圖2係圖1所示背光模組之光學板之立體圖。 圖3是本發明較佳實施例一所示光學板之立體示意圖。 圖4係圖3所示光學板之另一方向之立體圖。 12 201003236 圖5係圖3所示光學板之沿V-V線之剖視圖。 圖6係圖3所示光學板沿VI-VI線之剖視放大圖。 圖7係測試樣品1之光強測試圖。 圖8係測試樣品2之光強測試圖。 * 圖9係測試樣品3之光強測試圖。 圖10係本發明較佳實施例二之光學板之剖面示意圖。 圖11係本發明較佳實施例三之背光模組之示意圖。 【主要元件符號說明】 光學板 20、30 第一表面 201 ' 301 第二表面 203 、 303 長條狀孤形凸起 204 ' 304 長條狀V形凸起 205 背光模組 200 框架 21 光源 22 13201003236 IX. Description of the Invention: [Technical Field] 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] Referring to Figure 1, there is shown a conventional direct type backlight module 100 comprising a frame 11 and a plurality of light sources 12 disposed inside the frame 11, and disposed above the light source 12 and covering the frame 11 Diffusion plate 13. / When in use, light generated by the complex light source 12 enters the diffusion plate 13 and is diffused. However, after being diffused through the diffusion plate 13, the angle of light exiting from the diffusion plate 13 becomes more disordered, so that the brightness thereof is not high in a specific viewing angle range; and since the light source 12 transmits more light directly above it, diffusion It is often difficult for the plate 13 to directly diffuse the light from the light source 12 uniformly, so that the light emitted from the diffusing plate 13 is liable to cause image sticking of the light source, that is, a region where the intensity of light is different. f In order to improve the brightness of the backlight module 100 in a specific viewing angle range, and to avoid the generation of residual light of the light source, thereby improving the uniformity of the light emitted by the backlight module 100, an optical plate 10 and an upper portion are usually disposed above the diffusion plate 13. Diffusion sheet 14. As shown in Fig. 2, the optical plate 10 includes a transparent substrate 101 and a ruthenium layer 103 formed on the transparent substrate 101. The prism layer 103 has a plurality of elongated V-shaped projections 105 thereon. The elongated V-shaped projections 105 of the optical plate 10 cause a certain degree of convergence of the outgoing light, thereby increasing the brightness of the backlight module 100 over a particular viewing angle. The upper diffusion sheet 14 can further diffuse the light emitted from the optical plate 10. 7 201003236 However, when light is transmitted in the optical plate 10 and the upper diffusion sheet 14, part of the light is absorbed to cause light loss; and there is an air layer between the optical plates ig and :=14, which increases the light transmission (4) The interface between the two in the process increases the interface loss of light transmission and reduces the light utilization rate. SUMMARY OF THE INVENTION It is necessary to provide a backlight module and an optical plate thereof which can improve the effective utilization of light and uniform light emission. a backlight module comprising a frame, a light source and an optical plate, wherein the optical plate is disposed above the light source, and comprises a transparent body, the first surface and the first surface opposite to the first surface =, the first surface of the transparent body is a plane, the second surface has a plurality of strip-shaped arcuate protrusions and a plurality of mutual extension directions and the strip shape: a table:: ; = face, Zhao includes a first surface, the first surface of the transparent body, the · w surface, the second surface has a plurality of long parallel arc-shaped protrusions parallel to each other and a plurality of parallel strip-shaped v-shaped protrusions And the extending direction of the elongated protrusion intersects with the extending direction of the elongated V-shaped protrusion. The convexity of the = convex == group is due to the fact that the long arc-like arc on the second surface intersects with the extending direction of the long ridge-shaped bulge, and the curved surface structure is changed from the mutual father's fault, which is advantageous for Injecting into the optical plate: the optical effect of specific refraction, reflection and diffraction of the light, such that the light emitted from the optical plate is concentrated in a specific viewing angle range, and in the same time 201003236, the light can be diffused to weaken Even avoiding the residual image of the light source, the uniformity of the light output of the backlight module is improved, and the interface loss caused by the upper diffusion sheet is avoided, and the light utilization efficiency is improved. [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. 3 to FIG. 6, there is shown an optical plate 20 according to a preferred embodiment of the present invention. The optical plate 20 is composed of a transparent body including a first surface and a second surface opposite to the first surface 201. 3. The first surface 2〇1 is a plane, and the second surface 203 has a plurality of long arc-shaped protrusions 2〇4 parallel to each other and a plurality of long strip-shaped V-shaped protrusions 2〇5 which are parallel to each other, and a plurality of strip-shaped curved shapes The extending direction of the projection 204 intersects with the extending direction of the plurality of elongated v-shaped projections 2〇5. In this embodiment, the extending direction of the plurality of elongated arc-shaped protrusions 2〇4 and the extending direction of the plurality of elongated strip-shaped V-shaped protrusions 205 are perpendicular to each other, and the section of the elongated arc-shaped protrusions 204 is a semi-arc shape. The center-to-space spacing of two adjacent strip-shaped arcuate protrusions v 204 is denoted by p, and the radius is denoted by R; the center-to-center spacing of two adjacent strip-shaped v-shaped protrusions 205 is denoted as Pi; The height of the protrusion 2〇4 and the elongated V-shaped protrusion 205 is denoted by η, and p, R, Pl & H satisfy the following relationship: 0.025 mm SPS1.5 mm, p/4'Rg2P, 0.025 mm $ Pi S 1 mm, 〇.〇 1 mm SHgR. In other words, the center-to-center spacing P of the adjacent two cylindrical protrusions 204 may be 〇25 mm to ι.5 mm, the radius R may be 0-006 mm to 3 mm, and the adjacent two long strip-shaped v-convex The center pitch ρι of 2〇5 may be 0.025 mm to 1 mm, and the length of the elongated arc-shaped protrusion 2〇4 and the elongated V-shaped protrusion 205 may be 〇1 mm to 3 mm. . Further, the apex angle 该 of the strip 9 201003236-shaped V-shaped projection 205 is 80 degrees to 100 degrees. Further, by adjusting the size of the apex angle 长 of the long V-shaped projection 205, the brightness enhancement and the viewing angle of the optical plate 20 can be adjusted over a certain distance. The optical plate 20 may have an overall thickness Τ of 0.4 mm to 4 mm. The optical plate 20 is formed by injection molding of one or more of polymethyl methacrylate, polycarbonate, polystyrene, and styrene-methyl methacrylate copolymer. During the preparation process, a recessed structure corresponding to the elongated arcuate projections 204 and the elongated V-shaped projections 205 is provided on the mold so that the optical sheet 20 can be formed in a single injection molding process. The optical plate 20 is integrally formed by injection molding, and the long arc-shaped protrusions 204 and the elongated V-shaped protrusions 205 on the upper surface of the optical plate 20 are formed together with other portions of the optical plate 20 to form an elongated shape. The protrusions 204 and the elongated V-shaped protrusions 205 have a higher structural strength, and at the same time, can enhance the bonding force of the elongated arc-shaped protrusions 204 and the elongated V-shaped protrusions 205 and other portions of the optical plate 20. Thereby, the risk of the elongated arcuate projections 204 and the elongated V-shaped projections 205 being damaged in use can be avoided or reduced. In order to further verify that the optical plate 20 can specifically diffuse light incident thereon, a sample as listed in Table 1 is specifically selected for comparison test, and the results are shown in Figs. 7 to 9. Table 1 Test sample Sample No. Sample composition 1 Light-emitting diode 2 Light-emitting diode + optical plate 10 3 Light-emitting diode + optical plate 20 10 201003236 Analysis of the results shown in Figure 7, Figure 8 and Figure 9 'Light-emitting diode The emitted light is a bright spot with a high central intensity; the light emerging from the optical plate 1〇 forms a bright spot with two centers of high intensity; and the light emitted from the optical plate 20 is diffused into two longer lengths and a uniform brightness. Light band. It can be seen that the optical plate has the advantages of generating a virtual light source and generating a light band. Referring to Figure 10, 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 2A of the preferred embodiment, and the first surface 301 is planar. The difference is that the long arc-shaped projection 304 of the second surface 3〇3 has a semi-elliptical cross section. Of course, the cross section of the elongated arcuate projection 3〇4 may be other shapes such as a gradually expanding curved surface. Referring to FIG. 11, a backlight module 200 according to a third embodiment of the present invention includes the optical plate 2, the frame 21, and the light source 22. The light source is located in the frame 21, and the optical plate is disposed. Above the light source 22. The frame 21 may be made of metal or plastic having high reflectivity or metal or plastic coated with a high reflectivity coating. The C light source 22 can be a line source or a point source, such as a cold cathode fluorescent lamp and a light emitting diode. In this embodiment, a cold cathode fluorescent lamp is arranged closely, and the cold cathode fluorescent lamp is arranged closely. The direction in which the cathode fluorescent lamp extends is the same as the direction in which the elongated v-shaped projections 2〇5 or the elongated arcs 2204 on the second surface 203 of the optical plate 20 extend. The first surface 2〇1 of the optical plate 2〇 in the backlight module 200 is close to the light source and the second surface 203 is away from the light source 22. The extending direction of the long arc-shaped protrusions 204 from the second surface 2〇3 and the extending direction of the long v-shaped protrusions 2〇5 are perpendicular to each other, thereby interlacing to form a curved surface structure; 201003236 The number of cold cathode fluorescent lamps are closely arranged, and the extending direction of the plurality of cold cathode camping lamps and the elongated v-shaped protrusions 2〇5 or elongated arc-shaped protrusions on the second surface 203 of the optical plate 20 The extension direction of the 204 is the same, which is to facilitate the specific reflection, reflection and diffraction of the light incident on the optical plate 20, thereby allowing the light emitted from the optical plate 20 to be specifically diffused, thereby forming a uniform brightness. The bright side of the sentence. It can be seen that the backlight module can reduce or even avoid the residual image of the light source, improve the uniformity of the light output of the backlight module, avoid the interface loss caused by the upper diffusion sheet, and improve the light utilization efficiency. Of course, when the light source 22 is a point source, the point sources are arranged closely in an array, which also achieves the effect of using a line source. It can be understood that when the distance between the light sources 22 is large, a diffusion plate can be added between the optical plate 20 and the light source 22 of the backlight module 200 of the present invention, so that the light can be further diffused evenly, and the backlight module can be improved. Light uniformity. It is understood that the optical plate 20 can be used as a light diffusing plate because of its good light diffusing function. (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 a preferred embodiment of the present invention, and those who are familiar with the skill of the present invention are in the spirit of the invention. The equivalent modifications or variations are to be included in the following patent application. [Simplified Schematic] FIG. 1 is a schematic cross-sectional view of a conventional backlight module. FIG. 2 is an optical diagram of the backlight module shown in FIG. Figure 3 is a perspective view of the optical plate of the preferred embodiment of the present invention. Figure 4 is a perspective view of the optical plate of Figure 3 in another direction. 12 201003236 Figure 5 is an optical plate of Figure 3. Fig. 6 is a cross-sectional enlarged view of the optical plate shown in Fig. 3 taken along line VI-VI. Fig. 7 is a light intensity test chart of test sample 1. Fig. 8 is a light intensity test chart of test sample 2. Figure 9 is a cross-sectional view of an optical plate according to a preferred embodiment of the present invention. Figure 11 is a schematic view of a backlight module according to a preferred embodiment of the present invention. Explanation of symbols] Optical plates 20, 30 A surface 201 '301 second surface 203, 303 elongated arc-shaped protrusions 204' 304 elongated V-shaped protrusions 205 of the backlight light source module 200 of the frame 21 22 13