16929twf.doc/g 九、發明說明： 【發明所屬之技術領域】 本發明是有關於一種光學板片及其製造方法，且特別 是有關於一種用於背光模組之光學板片及其製造方法以及 應用此光學板片之背光模組。 【先前技術】 隨著科技的進步，視訊或影像裝置之體積日漸趨於輕 薄。因此’配合光電技術與半導體製造技術所發展之平面 式顯示器(Flat Panel Display)，例如液晶顯示器(LCD)、有 機發光顯示器（OLED)或是電漿顯示器（piasma Display Panel, PDP)，已逐漸成為顯示器產品之主流，而其中又以 液晶顯示器為目前顯示器產品的主流。 值得注意的是，由於液晶顯示面板本身並不會發光， 故必須藉由月光模組提供液晶顯示面板所需之面光源，使 知·液晶顯不器達到顯示的效果，並同時獲得足夠之亮度與 對比。因此背光模組設計的良E，實足以影響液晶顯示器 的顯示品質。 β圖1A係繪示習知—種背光模組的結構示意圖及其所 提供之面光源的亮度與位置的_圖。請參考圖1Α，習知 f t莫組_係-直下式背光模組’其包含—燈箱ii〇a、 以及多個光源12Ga。這些光源論為冷陰 料扣燈官’其細的間腿置於_ 11()a底部，而 ，政板⑽則配置於燈箱隱之出光截面ma處。這些 先源12Ga所發射出來的光線，在_擴散板m， 16929twf.doc/g 會形成一面光源，以作為液晶顯示面板所需之光源。 習知擴散板130a中具有多個光散射粒子132a，以達 到均勻擴散光線的效果。具體而言，習知的擴散板13〇a 係以射出成型方式製造，其材料通常為塑膠類，例如是聚 碳酸酯(polycarbonate, PC) ’且在此塑膠材料中摻雜有光散 射粒子132a。因此，在擴散板13〇a成型之後内部會含有 這些光散射粒子132a，且其係均勻地分布在擴散板13〇a 之中。當光源120a所發出的光線入射擴散板13如後，大 部分的光線會被光散射粒子132a散射，以達到擴散的效 果。 然而’由於習知背光模組l〇〇a所提供的面光源位於 光源120a上方之部分較其餘部分亮，且亮度相差甚多，因 此面光源的均勻度較差。 圖1B與圖1C係繪示習知另兩種背光模組的結構示意 圖及其所提供之面光源的亮度與位置的關係圖。請先參考 圖1B’為了改善上述面光源均勻度較差的現象，習知背光 模組100b中，係使用光散射粒子132b的分·布密度較高之 擴政板130b。其中’因為光散射粒子132b分布密度高的 關係，使得光源120b所提供之光線的穿透率較低，如此雖 然可以改善面光源位於光源120b上方之部分與其餘部分 之焭度差’以提高面光源之均勻度’但卻也降低了面光源 的整體亮度。 請參考圖1C，為了改善背光模組100a所提供之面光 源的均勻度較差的問題，在習知背光模組100c中，因位於 1322306 16929twf.doc/g 組作為實施例說明之，然其並非用以限定本發明之態樣。 圖2係繪示根據本發明之較佳實施例的背光模組示意 圖。明參考圖2，背光模組2〇〇例如是一直下式背光模組， 其包括一具有一出光截面212的燈箱210、多個光源220 ' 以及光學板片。其中，光源220係以適當間距配置 於燈箱210之底部，出光截面212係位於燈箱21〇上方。 光學板片230包括配置於燈箱21〇之出光截面212處的透 光基板232，以及多個配置於透光基板232内的光散射粒 φ 子234。透基板232係區分為多個位於光源22〇上方之 第一，塊236，以及多個位於相鄰兩第一區塊236之間的 第一，塊238，且各第一區塊236内之光散射粒子234的 分佈也、度大於各第二區塊238内之光散射粒子234的分佈 密度。 當光源220所提供之光線自燈箱21〇之出光截面212 入射光學板;i 230巾時’由於第—區塊236的光散射粒子 234的分布密度較高，所以使射入第一區塊236内的光線 鲁 易被散射到相鄰於第一區塊236之第二區塊238，因此光 線在位於光源220上方之第一區塊236内的穿透率較低， :、可降低月光模組200所提供之面光源位於光源上方 部分的亮度。另一方面，當光線射入第二區塊238之中時， 由=第二區塊238中的光散射粒子234之分布密度較低， 2光線的穿透率較高。如此—來，即可降低背光模組· 所提供之面光源位於光源22〇上方部分與其餘部分的亮度 差，因此背光模組200所提供之面光源的均勻度較佳。又 16929twf. doc/g 此外，相較於習知背光模組l〇〇b(如圖IB所示），在 本貫施例之背光模組2〇〇中，因第二區塊238内的光散射 粒子234分布密度較低，使得第二區塊238之光穿透率較 高，因此可以提高面光源的亮度。另外，由於在背光模組 200中，不需增加光源220與光學板片23〇的間距，所以 可在不增加整體厚度的情況下提供均勻度較佳的面光源， 以使液晶顯示裝置符合現今電子產品追求輕薄短小的趨 勢。 本發明一較佳實施例中，為了進一步提高面光源的均 勻度，可於光學板片230上再配置一光學膜片240。此光 學膜片240例如是一擴散片、一增光片或是上述之組合。 此外’在此實施例中背光模組200所使用的光源220可以 是冷陰極螢光燈管或是發光二極體陣列。透光基板232的 材質例如是塑膠類材料，如聚碳酸酯(p〇lycarb〇nate，pc)、 聚笨乙烯（poly styrene，PS)或聚曱基丙烯酸曱酯 (polymethyl methacrylate，PMMA)。 圖3是本發明一實施例之液晶顯示裝置的結構示意 圖。請參照圖3，本實施例之液晶顯示裝置300包括一液 晶顯示面板310以及配置於液晶顯示面板310旁的一背光 模組320。其中，背光模組320是用以提供液晶顯示面板 310所需之顯示光源。此外，液晶顯示面板31〇例如包括 —上基板312、一下基板314以及配置於上基板312與下 基板314之間的一液晶層316。背光模組320例如是圖2 中所繪示之背光模組200或是擴散板内的光散射粒子之分 16929twf.doc/g 佈密度係隨著與光源組之距離而有不同的變化之 式的背光模組。 ^ 由於背光模組320可在不增加整體厚度的情況 均勻度較佳的面光源’所以此液晶顯示裝置細可在不辦 加整體厚度的前提下’艇出亮度與均勻 曰 本發明另提出-種光學板片的製造方法，以實ς上述 之光散射粒子的分佈密度可隨著與純組之距離而有不同 變化的擴散板。以下將針對此光學板片的製造方法作詳細 的介紹。 圖4Α至圖4C繪示本發明一實施例之光學板片的製造 方法的步驟流程圖。請參考圖4Α至圖4C，本實施例之光 學板片的製造方法包括下列步驟： 首先，如圖4A所示，提供一透光基板41〇，其材質 例如疋聚碳酸酯或聚曱基丙烯酸曱酯之類的塑膠類材料。 接著’如圖4B所示’利用雷射光束5〇照射透光基板 410於透光基板41〇内形成光散射粒子。更詳細地說， 在t貫施中例如是以雷射光束50聚焦於透光基板410内的 特定位藉由雷射光束50的高能量促使透光基板410 内的4寺疋位置其材料結構產生變化例如形成折射率不同 於透光基板41〇原材質的局部小範圍結構，進而形成一可 使光線部分㈣部分反射的練雜子420。之後，重覆 上述之動作’以雷射光束50照射透光基板410的多個不同 位置’便能形成多個光散射粒子420,而完成光學板片400 之製作（如圖4C所示）。 16929twf.doc/g 經由適當波長的雷射光束50 ’並聚焦於透光基板4i〇 内的特定位置，可控制光散射粒子420分佈的位置。在本 實施例中所選用的雷射為超短脈衝雷射，如Nd_YAG雷 射。此外，在本實施例中可同時使用多個雷射光束5〇照射 或聚焦於透光基板410的不同位置，以同時形成多個光散 射粒子420，進而提高光學板片400的生產效率，或者使 用可程式控制的雷射加工機台來進行準確而迅速的控制， 同樣也可提高光學板片400的生產效率。 本實施例之光學板片的製作方法’其好處在於製作過 程中’藉由變換雷射光束在透光基板内的聚焦處，便可控 制光散射粒子在透光基板内的生成位置，因此可準確地控 制透光基板中不同區塊之光散射粒子的分布密度，以形成 如圖2中所述之光學板片230。 值得一提的是，本實施例之光學板片的製作方法亦可 應用於導光糾或其他光學板片⑽成所需特定區塊之光 散射粒子的分佈密度控制。 综上所述，本發明之光學板片及其製造方法以及背光 模組至少具有下列優點： 1.本發明之光學板#卜目紐射㈣的分佈密度係 與光源之距離而有不_變化，所⑽用此光學板片 2认組能在不增加整體厚度的纽下，兼顧面光源之 冗又。均句度’以提高液晶顯示裝置的顯示品質。 H於本發明之背絲_厚度不會增加所以液晶 .4不裝置的整體厚度也^會增加，其可使液㈣示裝置符 16929twf.doc/g 合現今電子產品追求輕薄短小的趨勢β 3.本發明之光學板片的製造方法，因採用雷射光束照 射透光基板以形成光散射粒子，因此可精確控制透光基板 中不同區塊之光散射粒子的分佈密度。 雖然本發明已以較佳實施例揭露如上’然其並非用以 眼定本發明’任何熟習此技藝者，在不脫離本發明之精神 和範圍内’當可作些許之更動與潤飾，因此本發明之保護 範圍當視後附之申請專利範圍所界定者為準。 [圖式簡單說明】 圖1Α係繪示習知一種背光模組的結構示意圖及其所 提供之面光源的亮度與位置的關係圖。 圖1Β與圖1C係繪示習知另兩種背光模組的結構示意 圖及其所提供之面光源的亮度與位置的關係圖。 圖2為根據本發明之較佳實施例的背光模組示意圖。 圖3是本發明一實施例之液晶顯示裝置的結構示意 圖。 圖4Α至圖4C繪示本發明一實施例之光學板片的製造 方法的步驟流程圖。 【主要元件符號說明】 50雷射光束 l〇〇a、l〇〇b、100c、200、320 :背光模組 ll〇a、ll〇b、ll〇c、210 :燈箱 112a、112b、112c、212 :出光戴面 120a、120b、120c、220 :光源 1322306 16929twf.doc/gBACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an optical sheet and a method of manufacturing the same, and more particularly to an optical sheet for a backlight module and a method of fabricating the same And a backlight module using the optical sheet. [Prior Art] With the advancement of technology, the size of video or video devices has become increasingly thin. Therefore, the flat panel display developed by optoelectronic technology and semiconductor manufacturing technology, such as liquid crystal display (LCD), organic light emitting display (OLED) or plasmas display panel (PDP), has gradually become The mainstream of display products, and among them, liquid crystal displays are the mainstream of current display products. It is worth noting that since the liquid crystal display panel itself does not emit light, the surface light source required for the liquid crystal display panel must be provided by the moonlight module, so that the liquid crystal display device can achieve the display effect and at the same time obtain sufficient brightness. And contrast. Therefore, the good design of the backlight module is enough to affect the display quality of the liquid crystal display. FIG. 1A is a schematic view showing the structure of a conventional backlight module and the brightness and position of the surface light source provided. Referring to FIG. 1A, a conventional direct-lit backlight module includes a light box ii〇a and a plurality of light sources 12Ga. These light sources are in the form of cold and sturdy buckles. The thin legs are placed at the bottom of _ 11 () a, while the political panels (10) are placed at the light-emitting section ma of the light box. The light emitted by these precursors 12Ga will form a light source on the diffusion plate m, 16929twf.doc/g, which is used as a light source for the liquid crystal display panel. The conventional diffusion plate 130a has a plurality of light-scattering particles 132a in order to achieve an effect of uniformly diffusing light. Specifically, the conventional diffusion plate 13A is manufactured by injection molding, and the material thereof is usually plastic, such as polycarbonate (PC), and the plastic material is doped with light scattering particles 132a. . Therefore, these light-scattering particles 132a are contained inside after the diffusion plate 13〇a is molded, and are uniformly distributed in the diffusion plate 13〇a. When the light emitted from the light source 120a is incident on the diffusing plate 13, for example, most of the light is scattered by the light scattering particles 132a to achieve the effect of diffusion. However, since the surface light source provided by the conventional backlight module 10a is located above the light source 120a and is brighter than the rest, and the brightness is greatly different, the uniformity of the surface light source is poor. FIG. 1B and FIG. 1C are schematic diagrams showing the relationship between the brightness of the two other backlight modules and the brightness and position of the surface light source provided therein. Referring to Fig. 1B', in order to improve the phenomenon that the uniformity of the above-mentioned surface light source is poor, the conventional backlight module 100b uses the diffusing plate 130b having a high density of the light-scattering particles 132b. Wherein 'the light transmittance of the light source 120b is low because of the high density distribution of the light scattering particles 132b, so that the difference between the portion of the surface light source located above the light source 120b and the rest of the light source can be improved to improve the surface. The uniformity of the light source' also reduces the overall brightness of the surface source. Please refer to FIG. 1C. In order to improve the uniformity of the surface light source provided by the backlight module 100a, in the conventional backlight module 100c, the group is located at 1322306 16929 twf.doc/g as an embodiment, but it is not It is used to define the aspect of the invention. 2 is a schematic view of a backlight module in accordance with a preferred embodiment of the present invention. Referring to FIG. 2, the backlight module 2 is, for example, a direct-type backlight module, which includes a light box 210 having a light-emitting section 212, a plurality of light sources 220', and an optical sheet. The light source 220 is disposed at the bottom of the light box 210 at an appropriate pitch, and the light exiting section 212 is located above the light box 21〇. The optical sheet 230 includes a light transmitting substrate 232 disposed at the light exiting section 212 of the light box 21, and a plurality of light scattering particles φ 234 disposed in the light transmitting substrate 232. The through substrate 232 is divided into a plurality of first ones located above the light source 22A, a block 236, and a plurality of first blocks 238 located between the adjacent two first blocks 236, and each of the first blocks 236 The distribution of the light scattering particles 234 is also greater than the distribution density of the light scattering particles 234 in each of the second blocks 238. When the light provided by the light source 220 is incident on the optical plate from the light exiting section 212 of the light box 21; i is 230, because the light scattering particles 234 of the first block 236 have a higher distribution density, so that the first block 236 is injected. The inner ray is easily scattered to the second block 238 adjacent to the first block 236, so that the light has a lower penetration rate in the first block 236 above the light source 220, which can reduce the moonlight mode. The surface light source provided by group 200 is located at the upper portion of the light source. On the other hand, when light is incident into the second block 238, the distribution density of the light-scattering particles 234 in the second block 238 is lower, and the transmittance of the light is higher. In this way, the backlight module can be reduced. The surface light source provided is located at a position above the light source 22 与 and the rest of the brightness difference, so that the uniformity of the surface light source provided by the backlight module 200 is better. 16929twf. doc/g In addition, compared with the conventional backlight module l〇〇b (shown in FIG. 1B), in the backlight module 2〇〇 of the present embodiment, due to the second block 238 The light scattering particles 234 have a low distribution density, so that the light transmittance of the second block 238 is high, so that the brightness of the surface light source can be improved. In addition, since the distance between the light source 220 and the optical plate 23〇 is not increased in the backlight module 200, a surface light source with better uniformity can be provided without increasing the overall thickness, so that the liquid crystal display device conforms to the present day. Electronic products are pursuing a trend of lightness and shortness. In an embodiment of the invention, in order to further improve the uniformity of the surface light source, an optical film 240 may be disposed on the optical plate 230. The optical film 240 is, for example, a diffusion sheet, a brightness enhancement sheet or a combination thereof. In addition, the light source 220 used in the backlight module 200 in this embodiment may be a cold cathode fluorescent lamp tube or a light emitting diode array. The material of the transparent substrate 232 is, for example, a plastic material such as polycarbonate (polystyrene), polystyry (PS) or polymethyl methacrylate (PMMA). Fig. 3 is a view showing the configuration of a liquid crystal display device according to an embodiment of the present invention. Referring to FIG. 3, the liquid crystal display device 300 of the present embodiment includes a liquid crystal display panel 310 and a backlight module 320 disposed adjacent to the liquid crystal display panel 310. The backlight module 320 is a display light source required for providing the liquid crystal display panel 310. Further, the liquid crystal display panel 31 includes, for example, an upper substrate 312, a lower substrate 314, and a liquid crystal layer 316 disposed between the upper substrate 312 and the lower substrate 314. The backlight module 320 is, for example, the backlight module 200 illustrated in FIG. 2 or the light scattering particles in the diffusion plate. The density of the light scattering particles varies according to the distance from the light source group. Backlight module. ^ Since the backlight module 320 can uniformly uniform the surface light source without increasing the overall thickness, the liquid crystal display device can be used without the overall thickness, and the invention is further proposed. A method for producing an optical sheet is characterized in that the distribution density of the light-scattering particles described above can vary depending on the distance from the pure group. The manufacturing method of this optical sheet will be described in detail below. 4A to 4C are flow charts showing the steps of a method of manufacturing an optical sheet according to an embodiment of the present invention. Referring to FIG. 4A to FIG. 4C, the manufacturing method of the optical sheet of the embodiment includes the following steps. First, as shown in FIG. 4A, a transparent substrate 41 is provided, which is made of, for example, tantalum polycarbonate or polyacrylic acid. Plastic materials such as oxime esters. Next, as shown in Fig. 4B, the light-transmitting substrate 410 is irradiated with the laser beam 5 to form light-scattering particles in the light-transmitting substrate 41. In more detail, the specific position of the laser beam 50 focused on the transparent substrate 410 is caused by the high energy of the laser beam 50 to promote the material structure of the 4 temples in the transparent substrate 410. A change occurs, for example, to form a local small-range structure having a refractive index different from that of the transparent substrate 41, thereby forming a train 420 that partially reflects the light portion (four). Thereafter, by repeating the above-described operation 'the plurality of different positions ' of the light-transmitting substrate 410 irradiated with the laser beam 50, a plurality of light-scattering particles 420 can be formed, and the fabrication of the optical sheet 400 is completed (as shown in Fig. 4C). 16929 twf.doc/g The position at which the light-scattering particles 420 are distributed can be controlled via a laser beam 50' of a suitable wavelength and focused at a specific position within the light-transmitting substrate 4i. The laser selected for use in this embodiment is an ultrashort pulse laser such as a Nd_YAG laser. In addition, in the embodiment, a plurality of laser beams 5 同时 can be simultaneously used to illuminate or focus on different positions of the transparent substrate 410 to simultaneously form a plurality of light scattering particles 420, thereby improving the production efficiency of the optical sheet 400, or The use of a programmable laser processing machine for accurate and rapid control also increases the productivity of the optical sheet 400. The method for fabricating the optical sheet of the present embodiment has the advantage that the position of the light-scattering particles in the transparent substrate can be controlled by changing the focus of the laser beam in the transparent substrate during the manufacturing process. The distribution density of light-scattering particles of different blocks in the light-transmitting substrate is accurately controlled to form an optical sheet 230 as described in FIG. It is worth mentioning that the method of fabricating the optical sheet of the present embodiment can also be applied to the distribution density control of the light-scattering particles of the light-guiding or other optical sheets (10) into a desired specific block. In summary, the optical sheet of the present invention, the manufacturing method thereof and the backlight module have at least the following advantages: 1. The optical density of the optical sheet of the present invention (4) is different from the distance of the light source. (10) The optical plate 2 can be recognized by the optical plate 2 without paying attention to the overall thickness, and the surface light source is redundant. The uniformity degree is used to improve the display quality of the liquid crystal display device. H in the back yarn of the present invention _ thickness will not increase, so the overall thickness of the liquid crystal. 4 does not increase, which can make the liquid (four) display device 16929twf.doc / g nowadays electronic products pursue a light and short trend β 3 In the method for manufacturing an optical sheet of the present invention, since the light-transmitting substrate is irradiated with a laser beam to form light-scattering particles, the distribution density of light-scattering particles in different blocks in the light-transmitting substrate can be precisely controlled. While the present invention has been described in its preferred embodiments, the present invention is not intended to be limited to the invention, and the invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing the structure of a conventional backlight module and the relationship between the brightness and position of the surface light source provided. FIG. 1A and FIG. 1C are diagrams showing the structure of two other backlight modules and the relationship between the brightness and the position of the surface light source provided. 2 is a schematic diagram of a backlight module in accordance with a preferred embodiment of the present invention. Fig. 3 is a view showing the configuration of a liquid crystal display device according to an embodiment of the present invention. 4A to 4C are flow charts showing the steps of a method of manufacturing an optical sheet according to an embodiment of the present invention. [Description of main component symbols] 50 laser beams l〇〇a, l〇〇b, 100c, 200, 320: backlight modules 11〇a, 11〇b, 11〇c, 210: light boxes 112a, 112b, 112c, 212: light-emitting wearing surface 120a, 120b, 120c, 220: light source 1322306 16929twf.doc/g
130a、130b、130c、230、400 :光學板片 132a、132b、132c、234、420 :光散射粒子 232、410 :透光基板 236 :第一區塊 238:第二區塊 _ 240 :光學膜片 300 :液晶顯示裝置 310 .液晶顯不面板 312 :上基板 314 :下基板 316 :液晶層 15130a, 130b, 130c, 230, 400: optical sheets 132a, 132b, 132c, 234, 420: light scattering particles 232, 410: light transmissive substrate 236: first block 238: second block _ 240: optical film Sheet 300: Liquid crystal display device 310. Liquid crystal display panel 312: upper substrate 314: lower substrate 316: liquid crystal layer 15