200827851 九、發明說明： 【發明所屬之技術領域】 特別關於一種背光模組 本發明係關於一種光學薄膜 之光學薄臈。 【先前技術】 一^年來，顯科觸快速發展，使得傳統陰極射線顯 不衣置逐漸被平面顯示裝置所取代，通常，平面顯示裝置 可為電漿顯示裝置統晶顯示裝置，並且已經應用在許多 種類之電子產品，例如筆記型電腦、電視及桌上型榮幕等 等。其中，液晶顯示裝置因具有耗電量低、發熱量少、重 量輕、以及非輻射性等優點，已經逐漸成為平面顯示裝置 的主流。 一般而言，液晶顯示装置係主要包含一液晶顯示面板 (Liquid Crystal Display Panel)以及一背光模組（Backlight200827851 IX. DESCRIPTION OF THE INVENTION: TECHNICAL FIELD OF THE INVENTION The present invention relates to an optical thin film of an optical film. [Prior Art] In the past one year, the rapid development of Xianke touch has made the conventional cathode ray display device gradually replaced by a flat display device. Generally, the flat display device can be a plasma display device, and has been applied to Many types of electronic products, such as notebook computers, televisions and desktop glory. Among them, the liquid crystal display device has gradually become the mainstream of flat display devices because of its advantages of low power consumption, low heat generation, light weight, and non-radiation. In general, a liquid crystal display device mainly includes a liquid crystal display panel (Liquid Crystal Display Panel) and a backlight module (Backlight)
Module)。其中，液晶顯示面板係主要具有兩玻璃基板、 以及一夾設於兩玻璃基板間的液晶層；而背光模組係可將 來自一光源的光線均勻地分佈至液晶顯示面板之表面。傳 統上，背光模組係以冷陰極螢光燈（Cold Cathode Fluorescent Lamp，CCFL)或發光二極體（Light Emitting Diode，LED)來作為光源。 请參照圖1 ’其係為習知技術之背光模組1之一剖面 示意圖，圖1中係以一側光式（EdgeType)之背光模組1 為例。背光模組1主要包含至少一光源11、一導光板12、 5 200827851 一反射板13、一擴散片14以及一稜鏡片15。 光源11係設置於導光板12之一侧，光源u係發出光 線並入射至導光板12。其中光源11可為至少一發光二極 體或一冷陰極螢光燈。導光板12之一侧可具有複數印刷 網點121或微結構，可用以破壞光線於導光板12内之全 反射’使得光線自導光板12之出光面122射出至擴散片 14。另外，反射板13係設置於導光板12相對出光面122 之一侧，係可將射出導光板12的光線反射回導光板12 内’以提高光線的利用率。 擴散片14及稜鏡片15係設置於導光板12之出光面 122側。其中，擴散片14主要是讓由導光板12射出的光 源更均勻分散；而稜鏡片15則是用以提高垂直於出光面 122方向之亮度，故市場上也稱之為增亮膜（Brightness Enhancing Film，BEF ) 〇 如圖2所示，其係為圖1中稜鏡片15之一放大示意 圖。習知技術中之棱鏡片15包含了一底面151以及與底 面相對之一結構面（Structural Surface) I52。而於結構面 I52上，主要是由複數個平行排列之等腰稜鏡153所構成， 各個4腰棱鏡153之間係形成^ V形溝槽（ groove) 154，也就是說溝槽的形狀並非圓角，且各個等腰 稜鏡153之高度係相同。 由於結構面152上的稜鏡圖案，係利用滾輪 作為模具’於光固膠上進行壓花（Embossing)製程後再許 紫外線固化來形成。其中，當滾輪與光固膠分離時，由於 6 200827851 稜鏡153之尺寸相當細緻，甚至達到微米級的製程精度。 因此，滚輪對應於V形溝槽154的地方較易有膠體殘留的 現象發生，不但容易影響後續加工製程之精準度，也易減 少滚輪的壽命。 有鑑於此，如何提供一種背光模組之光學薄膜，以解 決頂角易全面崩壞以及滚輪易有殘膠等問題，實為現今的 一大課題。 【發明内容】 有鑑於上述課題，本發明之目的為提供一種可解決頂 角易全面崩壞以及滾輪易有殘膠等問題之背光模組之光 學薄膜。 緣是，為達上述目的，本發明係揭露一種背光模組之 光學薄膜，係包含一稜鏡片，該稜鏡片係包含複數週期性 排列之稜鏡圖案，各該稜鏡圖案係分別具有一第一三角稜 鏡、一第一弧面稜鏡及一圓角，圓角係形成於第一三角稜 鏡與第一弧面稜鏡之間或形成於第一三角稜鏡相對於第 一弧面棱鏡之一侧。， · 承上所述，因依本發明背光模組之光學薄膜中至少具 有一三角棱鏡、一弧面棱鏡及一圓角，且圓角係形成於三 角稜鏡與弧面稜鏡之間或形成於三角稜鏡相對於弧面稜 鏡之一侧。與習知技術相比，本發明之背光模組之光學薄 膜由於具有圓角及弧面稜鏡，其中，圓角於製程中有助於 滾輪與稜鏡圖案之分離，可避免殘膠的發生。再者，弧面 200827851 _文鏡不具尖角故較二角棱鏡不易崩壞。另外，由三角稜 鏡、弧面稜鏡及圓角所構成之稜鏡圖案更可破壞稜鏡圖案 之規律性，避免於液晶顯示面板上產生條紋。再者，於實 施例中藉由三角稜鏡與弧面稜鏡的高度不相同，更可避免 於組裝液晶顯示裝置時，光學薄膜受外力而使得頂角全部 崩解的問題產生。 【實施方式】 以下將參照相關圖式，說明依本發明背光模組之光學 薄膜的複數實施例，其中相同的元件將以相同的參照符號 加以說明。 弟一實施例 首先，請參照圖3A至圖3B以說明本發明之第一實施 例背光模組之光學薄膜2。 請參照圖3A所示，背光模組之光學薄膜2係包含一 稜鏡片3。於本實施例中，背光模組之光學薄膜2更包含 一基板4，基板4係設置於稜鏡片3之一側，且基板4之 材質可為聚乙烯對苯二曱酸醋（Poly (ethylene terephthalate)，PET)，厚度可依實際設計需求而介於30μ m至250# m之間。 稜鏡片3可利用滾輪（Roller)作為模具，於基板4 上塗佈光固膠後進行壓花（Embossing)製程後，經紫外線 固化而形成。當然，稜鏡片3之製造方法並不限於此，也 可以利用滾輪壓印於具有光固膠的模具上，固化後再貼附 200827851 於基板4上。 請同時參照圖3A及圖3B所示，其中，圖3B係為圖 3A中其中一稜鏡圖案31之一放大示意圖。稜鏡片3包含 複數週期性排列之稜鏡圖案31，也就是說，各稜鏡圖案 31係重覆平行排列於基板4上，其中，各棱鏡圖案31可 具有一週期長度D，週期長度D係介於15/zm至300/zm 之間。 如圖3B所示，各稜鏡圖案31係分別具有一第一三角 稜鏡311，一第一弧面稜鏡312及一圓角313，於本實施 例中，各稜鏡圖案31之週期長度D係以52//m為例。其 中，圓角313係形成於第一三角稜鏡311與第一弧面稜鏡 312之間，藉由第一弧面稜鏡312以及圓角313之形成， 可使得稜鏡片3於製造時，減少滾輪上的殘膠形成，並可 延長濟輪的壽命。 各稜鏡圖案31之第一三角稜鏡311係具有一頂角a， 頂角a係介於75度至120度之間。且第一三角稜鏡311 具有一第一高度H1，第一弧面稜鏡312具有一第二高度 H2,圓角313具有一第三高度H3。其中，第一高度H1 係大於第二高度H2，第二高度H2係大於第三高度H3。 於本實施例中，係以頂角a為90度，第一高度H1為25 j m，第二高度H2為3.5 // m，第三高度H3為2.3 // m， 且第一高度HI、第二高度H2及第三高度H3係分別小於 0.5倍的週期長度D為例。這是因為經實驗結果發現，若 稜鏡的高度大於0.5倍的週期長度D時，則會造成稜鏡對 9 200827851 於光束之控制能力下降。 另外，第一弧面稜鏡312具有一第一曲率半徑R1，圓 角313具有一第二曲率半徑R2，第一曲率半徑R1與第二 曲率半徑R2可相同或不相同。於本實施例中，第一曲率 半徑R1約為0.5/im，第二曲率半徑R2約為0.2/zm，且 第一曲率半徑R1與第二曲率半徑R2係需小於0.75倍的 週期長度D為例。因為若第一弧面稜鏡312及圓角313的 曲率半徑Rl、R2大於0.75倍之週期長度D時，則光學薄 膜2中之稜鏡片3對於光束控制的能力則會變差，造成中 心亮度劇烈下降。 第二實施例 請參照圖4所示，於本實施例中，稜鏡圖案31仍以 一第一三角稜鏡311、一第一弧面稜鏡312及一圓角313 為例，其中，未實施例與第一實施例不同的地方主要在 於，圓角313係形成於第一三角棱鏡311相對於第一弧面 稜鏡312之一侧。 另外，本實施例之稜鏡圖案31的尺寸與第一實施例 亦不相同，在此，稜鏡圖案31之週期長度D為53# m， 第一三角稜鏡311之頂角a係為90度，第一高度HI為25 //m，第二高度H2為4//m，第三高度H3為2//m，且第 一高度H1及第二高度H2係分別小於0.5倍的週期長度 D，第一曲率半徑R1約為2/zm，第二曲率半徑R2約為 0·4 μ m，且第一曲率半徑R1與第二曲率半徑R2小於0.75 倍的週期長度D。其中，本實施例之稜鏡圖案31的作用與 200827851 功效皆與第一實施例之稜鏡圖案31相同，在此不再贅述。 第三實施例 請參照圖5所示，於本實施例中，與第一實施例及第 二實施例不同的地方主要在於，各稜鏡圖案31更具有一 第二弧面稜鏡314，換句話說，各稜鏡圖案31具有一第一 三角稜鏡311、一第一弧面稜鏡312、一第二弧面稜鏡314 ； 及一圓角313。其中，第一三角稜鏡311係位於第一弧面 稜鏡312及第二弧面稜鏡314之間，圓角313形成於第一 • 三角稜鏡311與第一弧面稜鏡312之間，然而，圓角313 的位置並非固定，圓角313亦可形成於第一三角稜鏡311 與第二弧面棱鏡314之間。另外，第二弧面稜鏡314具有 一第四高度H4及一第三曲率半徑R3，第四高度H4係小 於0.5倍的週期長度D，第三曲率半徑R3小於0.75倍的 週期長度D，且第四高度H4與第二高度H2可相同或不相 同，第一曲率半徑R1、第二曲率半徑R2及第三曲率半徑 R3可相同或不相同。 ® 另外，本實施例之稜鏡圖案31的尺寸與第一實施例 及第二實施例亦不相同，在此，稜鏡圖案31之週期長度D ‘ 為56/zm，第一三角稜鏡311之頂角a係為90度，第一高 - 度H1為25//m，第二高度H2為4/zm，第三高度H3為2 /zm，第四高度H4為4/zm，且第一高度H1、第二高度 H2、第三高度H3及第四高度H4係分別小於0.5倍的週期 長度D，第一曲率半徑R1與第三曲率半徑R3皆為2//m， 第二曲率半徑R2約為l//m，且第一曲率半徑R1、第二 11 200827851 曲率半徑R2及第三曲率半徑R3係需小於0.75倍的週期 長度D為例。於此，本實施例之稜鏡圖案31的作用與功 效皆與第一實施例及第二實施例之稜鏡圖案31相同，在 此不再贅述。 第四實施例 請參照圖6所示，於本實施例中，與第一實施例及第 二實施例不同的地方主要在於，各稜鏡圖案31更具有一 第二三角稜鏡315，換句話說，各稜鏡圖案31係具有一第 一三角稜鏡311、一第一弧面稜鏡312、一圓角313及一 第二三角稜鏡315，且第一弧面稜鏡312係形成於第一三 角稜鏡311及第二三角稜鏡315之間，圓角313形成於第 二三角稜鏡315相對於第一弧面稜鏡312之一側。然而， 第一弧面稜鏡312的位置並非固定，第一弧面稜鏡312亦 可設置於第一三角稜鏡311相對於第二三角稜鏡315。 其中，第二三角棱鏡315具有一頂角b及一第五高度 H5，且頂角b係介於75度至120度之間，第五高度H5 係小於0.5倍的週期長度D。另外，本實施例之稜鏡圖案 31的尺寸與上述該些實施例並不相同，在此，稜鏡圖案 31的週期長度D為100//m，第一三角稜鏡311及第二三 角稜鏡315之頂角a、b皆為90度，第一高度H1及第五 高度H5皆為25/zm，第二高度H2為4//m，第三高度H3 為2/zm，且第一高度H1、第二高度H2及第五高度H5係 分別小於0.5倍的週期長度D。第一曲率半徑R1約為2/z m，第二曲率半徑R2約為1/zm，且第一曲率半徑R1及 12 200827851 第二曲率半徑R2係需小於0.75倍的週期長度D為例。於 此，本實施例之稜鏡圖案31的作用與功效皆與上述該些 實施例之稜鏡圖案31相同，在此不再贅述。 第五實施例 請參照圖7所示，本實施例之稜鏡圖案31元件係與 第四實施例相同，棱鏡圖案31仍以一第一三角棱鏡311、 一第一弧面稜鏡312、一圓角313及一第二三角稜鏡315。 其中，本實施例與第四實施例不同的地方在於，第一 5瓜面 稜鏡312形成於第一三角稜鏡311及第二三角稜鏡315之 間，且圓角313形成於第一三角稜鏡311與第一弧面稜鏡 312之間。另外，本實施例之棱鏡圖案31的第一三角稜鏡 311、第一弧面稜鏡312、圓角313與第二三角稜鏡315之 參數、作用與功效皆與第四實施例相同，在此不再贅述。 接著，請參照圖8A至圖8D以說明本發明之第六實施 例背光模組之光學薄膜2。 第六實施例 請參照圖8A所示，背光模組之光學薄膜2係包含一 稜鏡片3。於本實施例中，背光模組之光學薄膜2更包含 一基板4，基板4係設置於稜鏡片3之一側。其中，基板 4之結構及功能係與第一實施例之基板4相同，在此不再 贅述。 請同時參照圖8A及圖8B所示，其中，圖8B係為圖 8A中其中一稜鏡圖案31之一放大示意圖。棱鏡片3包含 複數週期性排列之稜鏡圖案31，即各稜鏡圖案31係重覆 13 200827851 平行排列於基板4上’其中，各棱鏡圖案3 1可具有一週 期長度D，週期長度D係介於15/zm至300//m之間。於 本實施例中，各稜鏡圖案31之週期長度D係以100//m為 例。 另外，各稜鏡圖案31係分別具有一第一三角稜鏡 311，一第一弧面稜鏡312、一圓角313、一第二弧面稜鏡 314及一第二三角稜鏡315。第一三角稜鏡311及第二三角 稜鏡315係位於第一弧面稜鏡312及第二弧面稜鏡314之 間，且圓角313形成於第一三角稜鏡311與第二三角稜鏡 315之間。其中，圓角313形成的位置並非固定，當然也 可以於第一三角稜鏡311與第一弧面稜鏡312之間或於第 二三角稜鏡315與第二弧面稜鏡314之間形成圓角313。 藉由第一弧面稜鏡312、第二弧面稜鏡314及圓角313分 別形成於第一三角稜鏡311與第二三角稜鏡315之間，使 得稜鏡片3於製造時，減少滾輪上的殘膠形成，並可延長 滾輪的壽命。 另外，第一三角稜鏡311及第二三角稜鏡315係分別 具有一頂角a，b，且其係分別介於75度至120度之間，而 二頂角a，b之間的距離L1約為16// m。該等頂角a，b可 相等或不相同，於本實施例中，該等頂角a，b係相等且均 為90度，其中，頂角相同時，對於稜鏡圖案31而言可具 有較佳的光束控制能力。 承上，第一三角稜鏡311具有一第一高度H1，第一弧 面稜鏡312具有一第二高度H2,圓角313具有一第三高度 200827851 H3，第二弧面稜鏡314具有一第四高度H4，第二三角稜 鏡315具有一第五高度H5。其中，第一高度H1與第五高 度H5可相同或不相同，第二高度H2與第四高度H4可相 同或不相同，在本實施例中，係以第一高度H1與第五高 度H5相同（均為30// m)，第二高度與第四高度相同（均 、10//m)，第三高度H3為4/zm，且分別小於0·5倍的 週期長度D為例。各稜鏡圖案31係大致以圓角313之最 低高度的方向為對稱軸。 鲁 另外，於本實施例中，第一弧面棱鏡312具有一第一 曲率半徑R1，圓角313具有一第二曲率半徑R2、第二弧 面稜鏡314具有一第三曲率半徑R3,其中，第一曲率半徑 R1、第二曲率半徑R2及第三曲率半徑R3可相同或不相 同，且該等曲率半徑Rl、R2、R3皆需小於0.75倍的週期 長度D。於此，第一曲率半徑R1與第三曲率半徑R3相同 (均為5//m)，第二曲率半徑約為l//m。若該等曲率半 徑Rl、R2、R3太大，則整體結構會太平缓，使得稜鏡片 3幾乎不具有控制光束的能力；若該等曲率半徑Rl、R2、 R3相同時，則會使稜鏡片3具有較佳的光學效能，其中， ' 若該等曲率半徑Rl、R2、R3彼此不相同，則可降低稜鏡 - 圖案31的結構對稱性，以破壞稜鏡圖案31之規律性，避 免於液晶顯示面板上產生條紋。 再請參照圖8C及圖8D所示，其中，圖8C係為習知 技術中之光學薄膜15的光束視角圖，其稜鏡片上係具有 複數等腰直角三角形的稜鏡圖案，其中，橫軸代表視角， 15 200827851 縱轴代表亮度（W/sr，瓦特每立狴）。圖8D則為本實施例 之光束視角圖，比較後可知，當本實施例之該等三角稜鏡 311、315的高度小於0.5倍的週期長度D，且該等曲率半 徑Rl、R2、R3小於0·75倍之週期長度D時，稜鏡圖案可 將光束導向於45度視角内，且視角為30度以内的曲線較 習知平緩。換句話說，視角在30度以内的光均勻性較習 知結構好。此外，本實施例之中心亮度（即視角為0度時 之亮度）也可達到習知的94·3%，可見已具有產品化的潛 力。故當該等三角稜鏡311、315的高度小於0.5倍的週期 長度D，且該等曲率半徑Rl、R2、R3小於0.75倍之週期 長度D時，有極佳的光束導向能力及光均勻性。 第七實施例 請參照圖9所示，於本實施例中，與第六實施例不同 的地方主要在於，第一三角稜鏡311的第一高度Η1及第 二三角稜鏡315的第五高度Η5並不相同，第一弧面稜鏡 312的第二高度Η2與第二弧面棱鏡314的第四高度Η4也 不相同。於本實施例中，稜鏡圖案31的週期長度D為100 //m，第一三角稜鏡311的第一高度Η1為30//m、第一弧 面稜鏡312的第二高度H2約為13/zm、圓角313的第三 高度H3為20/zm、第二弧面稜鏡314的第四高度H4約為 16/zm、第二三角棱鏡315的第五高度H5為25//m，第一 三角稜鏡311及第二三角稜鏡315之頂角a、b皆為90度， 第一弧面棱鏡312之第一曲率半徑R1為5 、圓角313 之第二曲率半徑R2為l//m，第二弧面稜鏡314之第三曲 200827851 面半徑R3為10//m。於此，第一高度HI、第二高度H2、 第四高度H4及第五高度H5皆小於0.5倍的週期長度D， 且該等曲率半徑Rl、R2、R3小於0.75倍之週期長度D。 另外，因該等三角稜鏡的高度（第一高度H1及第二 高度H2)並不相同，若較高的三角稜鏡（第一三角稜鏡 311)於背光模組與液晶顯示面板組裝時，受外力壓迫導 致較高的三角稜鏡之頂角崩解破壞，則尚有另外一個較低 的三角稜鏡（第二三角稜鏡315)可正常的導引光線。如 此一來，不但可以避免光學薄膜的稜鏡頂角全面被破壞， 更有助於減少條紋（Moir6)的發生。 第八實施例 請參照圖10所示，本實施例與該等實施例不同的地 方主要在於，各稜鏡圖案31具有一第一三角稜鏡311、一 第一弧面稜鏡312、一圓角313、一第二三角.稜鏡315及 一第三三角棱鏡316，且第一弧面稜鏡312位於第一三角 稜鏡311與第三三角稜鏡316之間，圓角313係形成於第 一三角稜鏡311與第二三角稜鏡315之間。其中，圓角313 形成的位置並非固定，當然也可以於第一三角稜鏡311與 第一弧面稜鏡312之間或於第三三角稜鏡316與第一弧面 稜鏡312之間。此外，第三三角稜鏡316具有一頂角c及 一第六高度H6。 另外，稜鏡圖案31之尺寸也與前述該等實施例不同， 在此，稜鏡圖案31之週期長度D係以140μπι為例，第一 三角稜鏡311、第二三角稜鏡315及第三三角稜鏡316之 17 200827851 頂角a、b、c皆為90度，第一三角稜鏡311、第二三角稜 鏡315及第三三角稜鏡316之高度皆為24μιη，第一弧面 稜鏡312之高度為4μπι，圓角313之高度為2μπι，第一曲 率半徑R1及第二曲率半徑R2約為1/zm，且第一曲率半 徑R1及第二曲率半徑R2係需小於0.75倍的週期長度0 為例。本實施例之稜鏡圖案31的作用與功效皆與第七實 施例之稜鏡圖案31相同，在此不再贅述。 第九實施例 • 請參照圖11所示，於本實施例中，稜鏡圖案31仍以 一第一三角棱鏡311、一第一孤面棱鏡312、一圓角313、 一第二三角稜鏡315及一第三三角稜鏡316為例，其中， 本實施例與第八實施例不同的地方主要在於，圓角313形 成於第一三角稜鏡311與第二三角稜鏡315之間，第一弧 面棱鏡312係位於第三三角稜鏡316相對於第一三角稜鏡 311之一側。另外，本實施例之稜鏡圖案31的第一三角稜 鏡311、第一弧面棱鏡312、圓角313、第二三角稜鏡315 及第三三角稜鏡316之參數、作用與功效皆與第八實施例 相同，在此不再贅述。 ' 當然，除了上述實施例之外，本發明之背光模組之光 • 學薄膜中，各稜鏡圖案中之三角稜鏡之數量並不限定為 1~3個，弧面稜鏡之數量並不限定為1〜2個，圓角之數量 並不限定為1個，可依實際產品需求而設計。 综上所述，因依本發明背光模組之光學薄膜中至少具 有一三角稜鏡、一弧面稜鏡及一圓角，且圓角係形成於三 18 200827851 角稜鏡與弧面稜鏡之間或形成於三角稜鏡相對於弧面稜 鏡之一侧。與習知技術相比，本發明之背光模組之光學薄 膜由於具有圓角及弧面稜鐃，其中，圓角於製程中有助於 滾輪與稜鏡圖案之分離，<避免殘膠的發生。再者，弧面 稜鏡不具尖角故較三角稜鏡不易崩壞。另外，由三角稜 鏡、弧面稜鏡及圓角所構成之稜鏡圖案更可破壞稜鏡圖案 之規律性，避免於液晶顯示面板上產生條紋。再者，於實 施例中藉由三角稜鏡與弧面稜鏡的高度不相同，更可避免 鲁 於組裝液晶顯示裝置時，光學薄膜受外力而使得頂角全部 崩解的問題產生。 以上所述僅為舉例性，而非為限制性者。任何未脫離 本發明之精神與範疇，而對其進行之等效修改或變更，均 應包含於後附之申請專利範圍中。 【圖式簡單說明】 • 圖1係為習知技術背光模組之一示意圖； 圖2係為習知技術之稜鏡片之一示意圖； 圖係為本發明第一實施例之背光模組之光學薄膜 之一示意圖； 圖3B係為本發明第一實施例之背光模組之光學薄膜 中’其稜鏡圖案之一放大示意圖； 圖4係為本發明第二實施例之背光模組之光學薄膜 中’其棱鏡圖案之一^放大示意圖； 圖5係為本發明第三實施例之背光模組之光學薄膜 19 200827851 中，其稜鏡圖案之一放大示意圖； 圖6係為本發明第四實施例之背光模組之光學薄膜 中，其棱鏡圖案之一放大示意圖； 圖7係為本發明第五實施例之背光模組之光學薄膜 中，其稜鏡圖案之一放大示意圖； 圖8A係為本發明第六實施例之背光模組之光學薄膜 之一示意圖； 圖8B係為本發明第六實施例之背光模組之光學薄膜 中，其稜鏡圖案之一放大示意圖； 圖8C係為習知技術中之光學薄膜之一光束視角圖； 圖8D係為本發明第六實施例之背光模組之光學薄膜 之一光束視角圖； 圖9係為本發明第七實施例之背光模組之光學薄膜 中，其稜鏡圖案之一放大示意圖； 圖10係為本發明第八實施例之背光模組之光學薄膜 中，其棱鏡圖案之一放大示意圖；以及 圖11係為本發明第九實施例之背光模組之光學薄膜 中，其稜鏡圖案之一放大示意圖。 元件符號說明： 1 背光模組 11 光源 12 導光板 121 印刷網點 200827851Module). The liquid crystal display panel mainly has two glass substrates and a liquid crystal layer sandwiched between the two glass substrates; and the backlight module uniformly distributes light from a light source to the surface of the liquid crystal display panel. Traditionally, the backlight module uses a Cold Cathode Fluorescent Lamp (CCFL) or a Light Emitting Diode (LED) as a light source. Referring to FIG. 1 , a cross-sectional view of a backlight module 1 of the prior art is shown. FIG. 1 is an example of a backlight module 1 of an edge type. The backlight module 1 mainly includes at least one light source 11 , a light guide plate 12 , 5 200827851 , a reflection plate 13 , a diffusion sheet 14 , and a cymbal sheet 15 . The light source 11 is disposed on one side of the light guide plate 12, and the light source u emits light and enters the light guide plate 12. The light source 11 can be at least one light emitting diode or a cold cathode fluorescent lamp. One side of the light guide plate 12 may have a plurality of printed dots 121 or microstructures, which may be used to destroy the total reflection of light in the light guide plate 12 such that light is emitted from the light exit surface 122 of the light guide plate 12 to the diffusion sheet 14. In addition, the reflector 13 is disposed on one side of the light guide plate 12 opposite to the light exit surface 122, and reflects the light emitted from the light guide plate 12 back into the light guide plate 12 to improve the utilization of light. The diffusion sheet 14 and the cymbal sheet 15 are disposed on the light-emitting surface 122 side of the light guide plate 12. The diffuser 14 mainly distributes the light source emitted by the light guide plate 12 more uniformly, and the cymbal sheet 15 is used to increase the brightness perpendicular to the light exit surface 122. Therefore, the brightness enhancement film is also called a brightness enhancement film on the market. Film, BEF) As shown in FIG. 2, it is an enlarged schematic view of one of the cymbals 15 in FIG. The prism sheet 15 of the prior art includes a bottom surface 151 and a structural surface I52 opposite to the bottom surface. On the structural surface I52, it is mainly composed of a plurality of isosceles 153 arranged in parallel, and a V-shaped groove 154 is formed between each of the four waist prisms 153, that is, the shape of the groove is not Rounded corners, and the height of each isosceles 153 is the same. Since the ruthenium pattern on the structural surface 152 is formed by using an embossing process on the photo-solid glue by using a roller as a mold, ultraviolet curing is performed. Among them, when the roller is separated from the photo-curing glue, the size of the 6 200827851 稜鏡 153 is quite detailed, even reaching the micron-level process precision. Therefore, the roller corresponding to the V-shaped groove 154 is more likely to have a colloidal residual phenomenon, which not only easily affects the accuracy of the subsequent processing, but also reduces the life of the roller. In view of this, how to provide an optical film of a backlight module to solve the problem that the apex angle is easy to be completely collapsed and the roller is easy to have residual glue is a major issue today. SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide an optical film of a backlight module which can solve the problem that the top corner is easy to be completely collapsed and the roller is easy to have residual glue. In order to achieve the above object, the present invention discloses an optical film of a backlight module, which comprises a cymbal film comprising a plurality of periodically arranged 稜鏡 patterns, each of the 稜鏡 patterns having a first a triangular ridge, a first curved surface and a rounded corner, the rounded corner is formed between the first triangular ridge and the first curved surface or formed on the first triangular ridge relative to the first curved prism One side. According to the above, the optical film of the backlight module according to the present invention has at least one triangular prism, a curved prism and a rounded corner, and the rounded corner is formed between the triangular ridge and the curved surface or formed. On the side of the triangular ridge relative to the curved surface. Compared with the prior art, the optical film of the backlight module of the present invention has rounded corners and curved surface defects, wherein the rounded corners facilitate the separation of the roller and the enamel pattern during the process, thereby avoiding the occurrence of residual glue. . Furthermore, the curved surface 200827851 _ the mirror does not have a sharp corner, so it is not easy to collapse than the prism. In addition, the 稜鏡 pattern formed by the triangular prisms, the curved ridges and the rounded corners can destroy the regularity of the 稜鏡 pattern and avoid streaking on the liquid crystal display panel. Further, in the embodiment, since the heights of the triangular ridges and the curved ridges are different, it is possible to avoid the problem that the optical film is subjected to an external force and the apex angle is completely disintegrated when the liquid crystal display device is assembled. [Embodiment] Hereinafter, a plurality of embodiments of an optical film of a backlight module according to the present invention will be described with reference to the accompanying drawings, wherein the same elements will be described with the same reference numerals. First Embodiment Referring to Figures 3A to 3B, an optical film 2 of a backlight module according to a first embodiment of the present invention will be described. Referring to FIG. 3A, the optical film 2 of the backlight module includes a cymbal 3. In this embodiment, the optical film 2 of the backlight module further comprises a substrate 4, the substrate 4 is disposed on one side of the cymbal 3, and the material of the substrate 4 is polyethylene terephthalate (Poly (ethylene) Terephthalate), PET), the thickness can be between 30μm and 250# m depending on the actual design requirements. The bracts 3 can be formed by using a roller (Roller) as a mold, applying a photo-curing adhesive to the substrate 4, performing an embossing process, and curing by ultraviolet rays. Of course, the manufacturing method of the cymbal sheet 3 is not limited thereto, and it may be embossed on a mold having a photo-curing adhesive by using a roller, and then cured, and then attached to the substrate 4 on 200827851. Please refer to FIG. 3A and FIG. 3B at the same time, wherein FIG. 3B is an enlarged schematic view of one of the 稜鏡 patterns 31 in FIG. 3A. The cymbal sheet 3 includes a plurality of periodically arranged 稜鏡 patterns 31, that is, each 稜鏡 pattern 31 is repeatedly arranged in parallel on the substrate 4, wherein each prism pattern 31 can have a period length D, and a period length D is Between 15/zm and 300/zm. As shown in FIG. 3B, each of the ridge patterns 31 has a first triangular ridge 311, a first curved surface 312 and a rounded corner 313. In this embodiment, the period length D of each 稜鏡 pattern 31 is shown. Take 52//m as an example. The rounded corner 313 is formed between the first triangular ridge 311 and the first curved surface 稜鏡 312. The first curved surface 稜鏡 312 and the rounded corner 313 are formed, so that the cymbal 3 can be manufactured. Reduce the formation of residual glue on the roller and extend the life of the wheel. The first triangular turns 311 of each of the meandering patterns 31 have an apex angle a, and the apex angle a is between 75 degrees and 120 degrees. The first triangular ridge 311 has a first height H1, the first curved surface 312 has a second height H2, and the rounded corner 313 has a third height H3. The first height H1 is greater than the second height H2, and the second height H2 is greater than the third height H3. In this embodiment, the apex angle a is 90 degrees, the first height H1 is 25 jm, the second height H2 is 3.5 // m, the third height H3 is 2.3 // m, and the first height HI, the first The period height D of the two heights H2 and the third height H3 are less than 0.5 times, respectively, as an example. This is because it has been found through experiments that if the height of the crucible is greater than 0.5 times the period length D, it will cause a decrease in the controllability of the beam to the beam. Further, the first curved surface 312 has a first radius of curvature R1, and the rounded corner 313 has a second radius of curvature R2, and the first radius of curvature R1 and the second radius of curvature R2 may be the same or different. In this embodiment, the first radius of curvature R1 is about 0.5/im, the second radius of curvature R2 is about 0.2/zm, and the first radius of curvature R1 and the second radius of curvature R2 are less than 0.75 times the period length D is example. Because if the curvature radii R1, R2 of the first curved surface 312 and the rounded corner 313 are greater than 0.75 times the period length D, the ability of the cymbal 3 in the optical film 2 to control the light beam is deteriorated, resulting in central brightness. Drastically falling. Referring to FIG. 4, in the embodiment, the 稜鏡 pattern 31 is still a first triangular 稜鏡 311, a first curved surface 312, and a rounded corner 313. The difference from the first embodiment is mainly that the rounded corner 313 is formed on one side of the first triangular prism 311 with respect to the first curved surface 312. In addition, the size of the meander pattern 31 of the present embodiment is different from that of the first embodiment. Here, the period length D of the meander pattern 31 is 53#m, and the top angle a of the first triangular turn 311 is 90. Degree, the first height HI is 25 //m, the second height H2 is 4//m, the third height H3 is 2//m, and the first height H1 and the second height H2 are respectively less than 0.5 times cycle length D, the first radius of curvature R1 is about 2/zm, the second radius of curvature R2 is about 0.4 μm, and the first radius of curvature R1 and the second radius of curvature R2 are less than 0.75 times the period length D. The function of the 稜鏡 pattern 31 of the present embodiment and the effect of the 200827851 are the same as those of the first embodiment, and will not be described herein. The third embodiment is shown in FIG. 5. In this embodiment, the difference between the first embodiment and the second embodiment is mainly that each of the 稜鏡 patterns 31 has a second curved surface 314, which is changed. In other words, each of the enamel patterns 31 has a first triangular ridge 311, a first curved surface 稜鏡 312, a second curved surface 稜鏡 314, and a rounded corner 313. The first triangular ridge 311 is located between the first curved surface 312 and the second curved surface 314, and the rounded corner 313 is formed between the first triangular ridge 311 and the first curved surface 312. However, the position of the rounded corner 313 is not fixed, and the rounded corner 313 may be formed between the first triangular ridge 311 and the second curved prism 314. In addition, the second curved surface 314 has a fourth height H4 and a third radius of curvature R3, the fourth height H4 is less than 0.5 times the period length D, and the third radius of curvature R3 is less than 0.75 times the period length D, and The fourth height H4 and the second height H2 may be the same or different, and the first radius of curvature R1, the second radius of curvature R2, and the third radius of curvature R3 may be the same or different. In addition, the size of the meander pattern 31 of the present embodiment is different from that of the first embodiment and the second embodiment. Here, the period length D' of the meander pattern 31 is 56/zm, and the first triangular turn 311 The apex angle a is 90 degrees, the first height - degree H1 is 25 / / m, the second height H2 is 4 / zm, the third height H3 is 2 / zm, the fourth height H4 is 4 / zm, and the A height H1, a second height H2, a third height H3, and a fourth height H4 are respectively less than 0.5 times the period length D, and the first radius of curvature R1 and the third radius of curvature R3 are both 2//m, and the second radius of curvature R2 is about l//m, and the first radius of curvature R1, the second 11200827851 radius of curvature R2, and the third radius of curvature R3 are required to be less than 0.75 times the period length D. Here, the function and the effect of the meandering pattern 31 of the present embodiment are the same as those of the first embodiment and the second embodiment, and will not be described again. The fourth embodiment is shown in FIG. 6. In this embodiment, the difference from the first embodiment and the second embodiment is mainly that each of the 稜鏡 patterns 31 has a second triangular 稜鏡 315. In other words, each of the cymbal patterns 31 has a first triangular ridge 311, a first curved surface 312, a rounded corner 313, and a second triangular ridge 315, and the first curved surface 312 is formed in the first Between a triangular ridge 311 and a second triangular ridge 315, a rounded corner 313 is formed on one side of the second triangular ridge 315 with respect to the first curved ridge 312. However, the position of the first curved surface 稜鏡 312 is not fixed, and the first curved surface 稜鏡 312 may also be disposed at the first triangular 稜鏡 311 with respect to the second triangular 稜鏡 315. The second triangular prism 315 has a apex angle b and a fifth height H5, and the apex angle b is between 75 degrees and 120 degrees, and the fifth height H5 is less than 0.5 times the period length D. In addition, the size of the meandering pattern 31 of the present embodiment is not the same as the above embodiments. Here, the period length D of the meandering pattern 31 is 100//m, the first triangular turn 311 and the second triangular edge. The apex angles a and b of the mirror 315 are both 90 degrees, the first height H1 and the fifth height H5 are both 25/zm, the second height H2 is 4//m, and the third height H3 is 2/zm, and the first The height H1, the second height H2, and the fifth height H5 are each less than 0.5 times the period length D. The first radius of curvature R1 is about 2/z m, the second radius of curvature R2 is about 1/zm, and the first radius of curvature R1 and 12 200827851 the second radius of curvature R2 are required to be less than 0.75 times the period length D. Therefore, the function and the effect of the 稜鏡 pattern 31 of the embodiment are the same as those of the 稜鏡 pattern 31 of the above embodiments, and details are not described herein again. The fifth embodiment is shown in FIG. 7. The 稜鏡 pattern 31 element of the embodiment is the same as that of the fourth embodiment. The prism pattern 31 still has a first triangular prism 311, a first curved surface 312, and a circle. An angle 313 and a second triangular angle 315. The difference between the present embodiment and the fourth embodiment is that the first five melons 312 are formed between the first triangular ridge 311 and the second triangular ridge 315, and the rounded corners 313 are formed in the first triangle.稜鏡 311 is between the first curved surface 稜鏡 312. In addition, the parameters, functions, and effects of the first triangular ridge 311, the first curved surface 312, the rounded corner 313, and the second triangular ridge 315 of the prism pattern 31 of the present embodiment are the same as those of the fourth embodiment. This will not be repeated here. Next, an optical film 2 of a backlight module according to a sixth embodiment of the present invention will be described with reference to Figs. 8A to 8D. Sixth Embodiment Referring to Fig. 8A, the optical film 2 of the backlight module includes a cymbal 3. In the embodiment, the optical film 2 of the backlight module further comprises a substrate 4, and the substrate 4 is disposed on one side of the cymbal 3. The structure and function of the substrate 4 are the same as those of the substrate 4 of the first embodiment, and will not be described herein. Please refer to FIG. 8A and FIG. 8B at the same time, wherein FIG. 8B is an enlarged schematic view of one of the 稜鏡 patterns 31 in FIG. 8A. The prism sheet 3 includes a plurality of periodically arranged 稜鏡 patterns 31, that is, each 稜鏡 pattern 31 is repeated 13 200827851 is arranged in parallel on the substrate 4 ', wherein each prism pattern 31 can have a period length D, and the period length D is Between 15/zm and 300//m. In the present embodiment, the period length D of each of the meandering patterns 31 is exemplified by 100/m. In addition, each of the ridge patterns 31 has a first triangular ridge 311, a first curved surface 312, a rounded corner 313, a second curved surface 314, and a second triangular yoke 315. The first triangular ridge 311 and the second triangular ridge 315 are located between the first curved surface 稜鏡 312 and the second curved surface 稜鏡 314, and the rounded corners 313 are formed on the first triangular ridge 311 and the second triangular ridge Between mirrors 315. The position where the rounded corners 313 are formed is not fixed. Of course, the first triangular turns 311 and the first curved surface 稜鏡 312 or between the second triangular 稜鏡 315 and the second curved 稜鏡 314 may be formed. Rounded corner 313. The first curved surface 稜鏡 312, the second curved surface 稜鏡 314 and the rounded corner 313 are respectively formed between the first triangular 稜鏡 311 and the second triangular 稜鏡 315, so that the cymbal 3 is reduced in manufacturing. The residual glue is formed and the life of the roller can be extended. In addition, the first triangular ridge 311 and the second triangular ridge 315 respectively have a apex angle a, b, and the distance between the two apex angles a, b is between 75 degrees and 120 degrees, respectively. L1 is approximately 16//m. The apex angles a, b may be equal or different. In this embodiment, the apex angles a, b are equal and both are 90 degrees. When the apex angles are the same, the 稜鏡 pattern 31 may have Better beam control capabilities. The first triangular ridge 311 has a first height H1, the first curved surface 312 has a second height H2, the rounded corner 313 has a third height 200827851 H3, and the second curved surface 314 has a The fourth height H4, the second triangular angle 315 has a fifth height H5. The first height H1 and the fifth height H5 may be the same or different, and the second height H2 and the fourth height H4 may be the same or different. In the embodiment, the first height H1 is the same as the fifth height H5. (all 30//m), the second height is the same as the fourth height (all, 10//m), the third height H3 is 4/zm, and the period length D which is less than 0.5 times each is taken as an example. Each of the meandering patterns 31 is substantially symmetrical about the direction of the lowest height of the rounded corners 313. In addition, in the embodiment, the first curved prism 312 has a first radius of curvature R1, the rounded corner 313 has a second radius of curvature R2, and the second curved surface 314 has a third radius of curvature R3. The first radius of curvature R1, the second radius of curvature R2, and the third radius of curvature R3 may be the same or different, and the radius of curvatures R1, R2, and R3 all need to be less than 0.75 times the period length D. Here, the first radius of curvature R1 is the same as the third radius of curvature R3 (both 5/m), and the second radius of curvature is about l//m. If the curvature radii R1, R2, R3 are too large, the overall structure will be too gentle, so that the cymbal 3 has almost no ability to control the light beam; if the curvature radii R1, R2, and R3 are the same, the cymbal will be made 3 has better optical performance, wherein 'if the radius of curvature R1, R2, R3 are different from each other, the structural symmetry of the 稜鏡-pattern 31 can be reduced to destroy the regularity of the 稜鏡 pattern 31, avoiding Stripes are produced on the liquid crystal display panel. Referring to FIG. 8C and FIG. 8D , FIG. 8C is a perspective view of a beam of the optical film 15 in the prior art, wherein the cymbal has a 稜鏡 pattern of a plurality of isosceles right triangles, wherein the horizontal axis Representative perspective, 15 200827851 The vertical axis represents brightness (W/sr, watts per stand). FIG. 8D is a perspective view of the beam of the present embodiment. After comparison, it can be seen that when the heights of the triangular ridges 311 and 315 of the embodiment are less than 0.5 times the period length D, and the curvature radii R1, R2, and R3 are smaller than When the period length D is 0.75 times, the 稜鏡 pattern can guide the light beam within a 45-degree angle of view, and the curve with a viewing angle of 30 degrees is gentler than conventional. In other words, the light uniformity of the viewing angle within 30 degrees is better than the conventional structure. In addition, the center luminance of the present embodiment (i.e., the luminance when the viewing angle is 0 degrees) can also reach the conventional 94.3%, which shows that it has the potential for productization. Therefore, when the heights of the triangular ridges 311 and 315 are less than 0.5 times the period length D, and the curvature radii R1, R2, and R3 are less than 0.75 times the period length D, the beam guiding ability and the light uniformity are excellent. . Referring to FIG. 9 in the seventh embodiment, in the present embodiment, the difference from the sixth embodiment is mainly in that the first height Η1 of the first triangular 稜鏡 311 and the fifth height of the second triangular 稜鏡 315 are The Η5 is not the same, and the second height Η2 of the first curved surface 312 is different from the fourth height Η4 of the second curved prism 314. In this embodiment, the period length D of the meander pattern 31 is 100 //m, the first height Η1 of the first triangular ridge 311 is 30//m, and the second height H2 of the first curved surface 312 is about 13/zm, the third height H3 of the rounded corner 313 is 20/zm, the fourth height H4 of the second curved surface 314 is about 16/zm, and the fifth height H5 of the second triangular prism 315 is 25// m, the apex angles a and b of the first triangular 稜鏡 311 and the second triangular 稜鏡 315 are both 90 degrees, the first radius of curvature R1 of the first curved prism 312 is 5, and the second radius of curvature R2 of the rounded corner 313 For l//m, the third curved surface of the second curved surface 稜鏡314, 200827851, has a radius R3 of 10/m. Here, the first height HI, the second height H2, the fourth height H4, and the fifth height H5 are all less than 0.5 times the period length D, and the curvature radii R1, R2, and R3 are less than 0.75 times the period length D. In addition, since the heights of the triangular ridges (the first height H1 and the second height H2) are not the same, if the higher triangular ridges (the first triangular ridges 311) are assembled in the backlight module and the liquid crystal display panel, When the external force is pressed to cause the top corner of the higher triangular sag to disintegrate and break, there is another lower triangular 稜鏡 (the second triangular 稜鏡 315) to guide the light normally. As a result, not only can the dome angle of the optical film be completely destroyed, but also the occurrence of streaks (Moir6) can be reduced. The eighth embodiment is shown in FIG. 10 , and the difference between the embodiment and the embodiments is mainly that each of the 稜鏡 patterns 31 has a first triangular 稜鏡 311 , a first curved surface 稜鏡 312 , and a rounded corner . 313, a second triangle 稜鏡315 and a third triangular prism 316, and the first curved surface 稜鏡 312 is located between the first triangular 稜鏡 311 and the third triangular 稜鏡 316, and the rounded corner 313 is formed in the first A triangular 稜鏡 311 and a second triangular 稜鏡 315. The position where the rounded corners 313 are formed is not fixed. Of course, it may be between the first triangular ridge 311 and the first curved ridge 312 or between the third triangular ridge 316 and the first curved ridge 312. Further, the third triangular ridge 316 has a vertex angle c and a sixth height H6. In addition, the size of the 稜鏡 pattern 31 is also different from the foregoing embodiments. Here, the period length D of the 稜鏡 pattern 31 is exemplified by 140 μπι, the first triangular 稜鏡 311, the second triangular 稜鏡 315, and the third Triangle 316 316 200827851 The top angles a, b, and c are all 90 degrees, and the heights of the first triangle 311, the second triangle 315, and the third triangle 316 are 24 μm, and the first arc surface is The height of the mirror 312 is 4 μm, the height of the rounded corner 313 is 2 μm, the first radius of curvature R1 and the second radius of curvature R2 are about 1/zm, and the first radius of curvature R1 and the second radius of curvature R2 are less than 0.75 times. The cycle length 0 is taken as an example. The function and effect of the 稜鏡 pattern 31 of this embodiment are the same as those of the 稜鏡 pattern 31 of the seventh embodiment, and will not be described herein. Ninth Embodiment In addition, as shown in FIG. 11, in the present embodiment, the 稜鏡 pattern 31 still has a first triangular prism 311, a first orphan prism 312, a rounded corner 313, and a second triangular ridge 315. And a third triangular crucible 316 is taken as an example, wherein the difference between the embodiment and the eighth embodiment is mainly that the rounded corner 313 is formed between the first triangular crucible 311 and the second triangular crucible 315, first The curved prism 312 is located on one side of the third triangular ridge 316 with respect to the first triangular ridge 311. In addition, the parameters, functions, and effects of the first triangular ridge 311, the first curved prism 312, the rounded corner 313, the second triangular ridge 315, and the third triangular ridge 316 of the 稜鏡 pattern 31 of the embodiment are all The eighth embodiment is the same and will not be described again. Of course, in addition to the above embodiments, in the optical film of the backlight module of the present invention, the number of triangular ridges in each 稜鏡 pattern is not limited to one to three, and the number of curved ridges is It is not limited to 1 to 2, and the number of rounded corners is not limited to one, and can be designed according to actual product requirements. In summary, the optical film of the backlight module according to the present invention has at least one triangular ridge, one curved surface and one rounded corner, and the rounded corners are formed on the three 18 200827851 corners and curved surfaces. Interposed or formed on one side of the triangular ridge relative to the curved surface. Compared with the prior art, the optical film of the backlight module of the present invention has rounded corners and curved edges, wherein the rounded corners are used in the process to facilitate the separation of the roller and the enamel pattern, < avoiding residual glue. occur. Moreover, the curved surface does not have a sharp corner, so it is not easy to collapse even if it is triangular. In addition, the 稜鏡 pattern formed by the triangular prisms, the curved ridges and the rounded corners can destroy the regularity of the 稜鏡 pattern and avoid streaking on the liquid crystal display panel. Further, in the embodiment, the heights of the triangular ridges and the curved ridges are different, and it is possible to avoid the problem that the optical film is subjected to an external force and the apex angle is completely disintegrated when the liquid crystal display device is assembled. The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the present invention are intended to be included in the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a backlight module of the prior art; FIG. 2 is a schematic diagram of a conventional technique; FIG. 2 is an optical diagram of a backlight module according to a first embodiment of the present invention; FIG. 3B is an enlarged schematic view showing one of the 稜鏡 patterns of the optical film of the backlight module of the first embodiment of the present invention; FIG. 4 is an optical film of the backlight module of the second embodiment of the present invention; FIG. 5 is an enlarged schematic view showing one of the 稜鏡 patterns in the optical film 19 200827851 of the backlight module according to the third embodiment of the present invention; FIG. 6 is a fourth embodiment of the present invention. FIG. 7 is an enlarged schematic view showing one of the prism patterns in the optical film of the backlight module according to the fifth embodiment of the present invention; FIG. 8A is an enlarged view of the 稜鏡 pattern in the optical film of the backlight module according to the fifth embodiment of the present invention; A schematic diagram of an optical film of a backlight module according to a sixth embodiment of the present invention; FIG. 8B is an enlarged schematic view showing one of the enamel patterns of the optical film of the backlight module of the sixth embodiment of the present invention; FIG. 8D is a perspective view of a light beam of an optical film of a backlight module according to a sixth embodiment of the present invention; FIG. 9 is an optical diagram of a backlight module according to a seventh embodiment of the present invention; FIG. 10 is an enlarged schematic view showing one of prism patterns in an optical film of a backlight module according to an eighth embodiment of the present invention; and FIG. 11 is a ninth embodiment of the present invention. In the optical film of the backlight module, one of the 稜鏡 patterns is enlarged. Component symbol description: 1 backlight module 11 light source 12 light guide plate 121 printing network point 200827851
122 出光面 13 反射板 14 擴散片 15 稜鏡片 151 底面 152 結構面 153 等腰稜鏡 154 V形溝槽 2 光學薄膜 3 稜鏡片 31 稜鏡圖案 311 第一三角稜鏡 312 第一弧面稜鏡 313 圓角 314 第二三角稜鏡 315 第二弧面稜鏡 316 第三三角稜鏡 4 基板 a，b，c 頂角 D 週期長度 HI 第一高度 H2 第二高度 H3 第二南度 H4 第四高度 21 200827851 H5 第五高度 H6 第六高度 LI 距離 R1 第一曲率半徑 R2 第二曲率半徑 R3 第三曲率半徑 22122 Light-emitting surface 13 Reflector 14 Diffuser 15 Flip 151 Bottom 152 Structure 153 Isosceles 稜鏡 154 V-shaped groove 2 Optical film 3 31 31 稜鏡 pattern 311 First triangular 稜鏡 312 First curved surface 稜鏡313 Rounded corner 314 Second triangular 稜鏡 315 Second curved surface 稜鏡 316 Third triangular 稜鏡 4 Substrate a, b, c Top angle D Period length HI First height H2 Second height H3 Second south degree H4 Fourth Height 21 200827851 H5 Fifth height H6 Sixth height LI Distance R1 First radius of curvature R2 Second radius of curvature R3 Third radius of curvature 22