200914940 九、發明說明： 【發明所屬之技術領域】 本發明係關於一種光學膜片（opticdsheet)、以及包含該光學膜 片之一種为光總成及一種液晶顯示器，且更具體而言，本發明係 關於一種藉由一單一膜片達成一擴散膜片（diffuser sheet)、一棱 鏡膜片（prism sheet)及一保護膜片（pr〇tect〇rsheet)之功能之光 學膜片、以及包含該光學膜片之―種背光總成及—種液晶顯示器。 【先前技術】 液晶顯示器係為-種平面顯示裝置，其利用液晶之電性及光學 特J·生,4不衫像，其中液晶具有介於液體與固體中間之特性。液晶 顯示器薄於且輕於其他顯示農置，並具有—更低之驅動電壓及更 低之功耗，故廣泛用於各種行業領域中。 因用於』7F〜像之顯不面板係為一種不能自行發光之不發光裝 置’故液晶顯示H需要使用—可單獨提供光線之背光總成。200914940 IX. INSTRUCTIONS OF THE INVENTION: TECHNICAL FIELD The present invention relates to an optical film (opticdsheet), and a light assembly comprising the optical film and a liquid crystal display, and more particularly, the present invention An optical film having a function of a diffuser sheet, a prism sheet, and a protective film by a single film, and the optical film comprising the same A kind of backlight assembly and a liquid crystal display. [Prior Art] A liquid crystal display is a type of flat display device which utilizes the electrical and optical properties of liquid crystals, and the liquid crystal has a property interposed between liquid and solid. LCD monitors are thinner and lighter than other display farms, and have a lower driving voltage and lower power consumption, so they are widely used in various industries. Since the display panel for the "7F~ image" is a non-light-emitting device that cannot emit light by itself, the liquid crystal display H needs to be used - a backlight assembly that can separately provide light.
一般而言，-背光總成包含：_燈單元；—導光㈣，用於自 導光；i散⑻，設置於該㈣元件之—上表面以擴 _ 稜鏡膜片’用於會聚自該擴散膜片發出之光線；以及 —保護膜片’用於保護該稜鏡膜片。因要分別安裝擴散 鏡膜片及保護膜片，故構成背光總成之部件數量增多、 數量增多，故很難將背光總成製丨 、σ 組裝製程之數量增多，此又=作:;更:， 高。 使-人σσ率升南，致使總體製造成本升 【發明内容】 5 200914940 本發明提供一種具多功能之光學膜片。 本發明亦提供一種包含一具多功能之光學膜片之背光總成。 本發明亦提供一種包含一具多功能之光學膜片之液晶顯示器。 根據本發明之一實施例，提供一種光學膜片，包含：一透明基 板，以及複數個三維圖案層，依序設置於該透明基板之一表面上。 該光學膜片更包含：功能珠，夾置於該透明基板之間；以及一三 維圖案層，設置於該複數個三維圖案層之最低位置上。此外，在 9又置於該複數個三維圖案層之最上位置之一三維圖案層頂上，該 光學膜片包含一預定表面粗糙度。 此外，於該光學膜片中，該複數個三維圖案層中該最上三維圖 案層包含矽酮丙烯酸酯（siHC0n acrylate)。此外，該複數個三維圖 案層具有自下部朝上部增大之一折射率。 根據本發明之另一實施例，提供一種光學膜片，包含：一透明 基板；一第一三維圖案層，設置於該透明基板之一側上；以及一 第二三維圖案層’設置於該第—三維圖案層上。 此時，該第-三維圖案層可具有凸紋之一外形，且該第二三維 圖案層包含至少一圖案，該至少一圖案係選自一稜鏡圖案、一雙 凸透鏡（lenticular)圖案、一微透鏡圖案以及一菲涅耳（Fresne〇 圖案。 此外’該第二三維圖案層包含一預定表面粗糖度於其頂部，且 該表面減度介於0.05微米至…微米之間。該第二三維圖案層 可包含石夕酮丙稀酸酯。 該光學膜片更包含複數功能珠，位於該透明基板與該第一三維 6 200914940 圖案層之間，且該等功能珠可係為光擴散珠。 在該光學臈片中，該第一三維圖案層之上表面與該第二三維圖 案層之下表面具有實質互補之形狀。 根據本發明之另一實施例，提供一種背光總成，包含：一燈單 凡；一導光元件，用於自該燈單元向上導引光線；以及如上所述 之光學膜片’設置於該導光元件之一上表面上。 根據本發明之又一實施例，提供一種液晶顯示器，包含：一顯In general, the backlight assembly comprises: a lamp unit, a light guide (four) for self-directing light, and an air diffuser (8) disposed on the upper surface of the (four) component to expand the diaphragm _ for convergence. The light emitted by the diffusing film; and the protective film 'is used to protect the diaphragm. Since the diffuser film and the protective film are separately installed, the number of components constituting the backlight assembly is increased and the number is increased, so that it is difficult to increase the number of the backlight assembly and the number of σ assembly processes, which is more: :, high. Increasing the σσ rate of the person, causing the overall manufacturing cost to rise. [Inventive content] 5 200914940 The present invention provides a multifunctional optical film. The present invention also provides a backlight assembly comprising a multi-functional optical film. The invention also provides a liquid crystal display comprising a multifunctional optical film. According to an embodiment of the present invention, an optical film comprising: a transparent substrate, and a plurality of three-dimensional pattern layers are sequentially disposed on a surface of the transparent substrate. The optical film further comprises: a functional bead sandwiched between the transparent substrates; and a three-dimensional pattern layer disposed at a lowest position of the plurality of three-dimensional pattern layers. Further, on top of the three-dimensional pattern layer which is placed at the uppermost position of the plurality of three-dimensional pattern layers, the optical film comprises a predetermined surface roughness. Further, in the optical film, the uppermost three-dimensional pattern layer of the plurality of three-dimensional pattern layers comprises siHC acrylate. Further, the plurality of three-dimensional pattern layers have a refractive index that increases from the lower portion toward the upper portion. According to another embodiment of the present invention, an optical film includes: a transparent substrate; a first three-dimensional pattern layer disposed on one side of the transparent substrate; and a second three-dimensional pattern layer disposed on the first - on a three-dimensional pattern layer. In this case, the first three-dimensional pattern layer may have one shape of the relief, and the second three-dimensional pattern layer includes at least one pattern selected from the group consisting of a 稜鏡 pattern, a lenticular pattern, and a a microlens pattern and a Fresnel pattern. Further, the second three-dimensional pattern layer comprises a predetermined surface roughness on top of the surface, and the surface reduction is between 0.05 micrometers to ... micrometers. The patterned layer may comprise a linaloic acid acrylate. The optical film further comprises a plurality of functional beads located between the transparent substrate and the first three-dimensional 6 200914940 pattern layer, and the functional beads may be light diffusion beads. In the optical cymbal, the upper surface of the first three-dimensional pattern layer and the lower surface of the second three-dimensional pattern layer have a substantially complementary shape. According to another embodiment of the present invention, a backlight assembly is provided, including: a light directing element for directing light upward from the light unit; and an optical film 'as described above disposed on an upper surface of the light guiding element. According to yet another embodiment of the present invention A liquid crystal display, comprising: a substantially
示面板’·以及如請求項16所述之f光總成，用於提供該光線至該 顯示面板。 在如上所述根據本發明之光學膜片、以及包含該光學膜片之背 光總成及液晶顯示n巾，該單—光學㈣具有域射性、聚光性 及擴散性之多種功能’且既不需要掩膜也不需要保護膜，故而在 成本降低、生產率及可加卫性方面非常優異，㈣可達成更輕、 更薄、更簡單且更小之液晶顯示器。 【實施方式】 在下文詳細說明及附圖中將詳述本發明之實施例。本發明之優 點及特徵以及達成本發明之方法將參照實施料以述明，現在將 參照附圖更全面地說明本發明之實施例。然而，本發明可實施為 諸多不同形式，而不應被視為僅限於本文所述之實_ :相反1’， 提供該等實施例旨在使本揭示内容透徹且完整，並向孰習 藝者全面傳達本發明之_。本發明僅由巾請專利範圍中所述之 定義加以界定。在本說明書中，各關中相同之參考編號指代相 同之元件。 200914940 以下’將參照第丨圖至第4圖說明根據本發明之一實施例 學膜片。 光 第1圖至第4圖係為剖視圖，其例示根據本發明一實施例之光 學膜片。 除光擴散功能以及繞射並將光線會聚至更高亮度之會聚功〜 外，根據本發明該實施例之光學膜片1〇〇、110、12〇及13〇 有一保護功能，以防止光學膜片100、110、丨20及130附近之其 他元件使其產生劃痕。 ' 如第1圖所示’光學膜片100可包含一透明基板1〇及複數個 維（以下簡稱為 「3D」）圖案層20及30。較佳地， 可於透明基板 10之一側提供一第一 3D圖案層20及一第二3D圖案層3〇 首先，透明基板10被造型為一由一無色透明合成樹脂形成之 板，以容許光線透射。形成透明基板1 〇之合成樹脂不受特別限制 而是亦可包含，舉例而言，聚對苯二曱酸乙-辟 一鮮®旨 (polyethylene-terephthalate )、聚萘二曱酸乙 酉旨 (polyethylene-naphthalate)、丙稀酸樹脂（acrylresin)、聚碳酸酉旨 (polycarbonate)、polysthylene、聚烯烴（polyolefine)、乙酸纖維 素（cellous acetate )、财氣候之聚氣乙烯（poly vinyl chloride )。在 該等材料中，具有優異透明度及高強度特性之聚對苯二曱酸乙二 醇酯或聚碳酸酯、以及具有增強之翹曲效能之聚對苯二甲酸乙二 醇醋更佳。 透明基板10之厚度不受特別限定，而是例如可為10〜1000 μιη， 且較佳為25〜600 μηι。透明基板10具有優異之機械強度及熱穩定 8 200914940 性，且具有一恰當之撓性，同時在上述厚度範 ㈣p 8透射光之損 第一 3D圖案層20設置於透明基板1〇上。用以擴散光線之第— 3D圖案層20可藉由形成凸紋而被糙化。第一 3D圖案層加之 紋形狀之突出部可藉不同方式造型成例如一之凸 ^ 一 紅轉橢圓 體、一正方棱錐（squarepyramid)以及一纖維，但本發明並 別限制為此一形狀。 、 構成第- 3D圖案層20之材料不受限定，而是可為例如丙稀酸 樹脂、聚氨基甲義（p()lyurethane)、聚醋（ρ〇ι购小氣美樹 脂、石夕基樹脂、聚醯胺酿亞胺（p〇】yamideimide)、環氧樹毅紫 外先固化樹脂。因此’可利用上述其中—種聚合物，或者可將其 中至少二種相混合。除聚合物外，第一犯圖案層可更包八二 微細無機或有機填料、-硬化劑、—增塑劑、各種句平劑 卿卜料光吸收劑、-抗氧化劑、—枯度調 及一光穩定劑。 劏 第一 3D賴料具有-相對低之折射率，例如折射率為⑸ 折=且車父佳係為以〜⑸。第一 3D圖案層2〇具有相對低之 折射率’以使自導光板人射之光線中大量之光線朝上擴散。 :卜，第，圖案層20可具有約為5·1〇〇微米之一平均厚度。 错由將第-3D圖㈣20形成為具有上述厚度 方向上有效騎聚紐。 Μ錢 此外’如第2圖所示，功能珠15 w + 3D_S 殊15可夹置於透明基板Η)與第- 2G之—表面間。此時，將功能珠以置於透明基板10 200914940 與第一 3D圖案層20之表面間包括以下二種情形：使功能珠15接 觸透明基板10，以及使功能珠15與透明基板10隔開（儘管圖未 示）。 功能珠15可例如係為一光擴散珠，用以增強光擴散功能。當功 能珠15係為一光擴散珠時’可均勻地擴散自透明基板1〇朝第一 3D圖案層20透射之光線。 當功能珠15係為光擴散珠時，光擴散珠可係為一無機填料或一 有機填料。無機填料可包括例如矽石（silica)、氫氧化鋁、氧化鋁、 氧化鋅、硫化鋇、石夕酸錢、碳酸約、以及氧化鈦，以便可使用上 述無機填料其中之一或者可混合其中之至少二者。有機填料可利 用藉由在形成以下物質之均聚物或共聚物之丙烯酸基微粒後覆蓋 另一種單體而形成之多層式多組分基微粒：胺基甲酸酯、耐綸、 石夕、三聚氰胺曱經（melamin-forumaldehyde)、苯並三聚氰二胺-曱酸（benzoguanamine-forumaldehyde )、甲基丙稀酸甲酯、丙烯 酸 、methatrile acid 、 甲基丙稀酸經乙基酯 (hydroxyethyl-methacrylate )、甲基丙稀酸經丙基酯 (hydroxypropyl-methacrylate )、丙烯醯胺（acrylamide )、經甲基 丙烯醯胺（methylolacrylamide )、曱基丙稀酸縮水甘油基醋 (glycidyl-methacrylate)、丙烯酸乙酯（ethylacrylate)、丙烯酸異 丁酉旨（isobutylacrylate)、丙稀酸正丁醋（normalbutylacrylate)以 及丙稀酸2-乙基己醋（2-ethylhyxylacrylate );烯烴基微粒，例如 聚乙烯、polysthylene及聚丙烯；以及丙稀酸基及烯烴基共聚物微 粒及均聚物微粒。 200914940 此項技術中之通常技術者易於理解，以上所述用作光擴散珠之 無機填料或有機填料僅供用於例示目的，且可代之以另一種可達 成本發明主要目的之眾所習知之材料，而非僅限於無機填料或有 機填料。 功能珠15具有呈單分散性及多分散性之微粒分佈，其形狀不受 特別限制，並可被造型為球體、紡錘體、針狀體、棒、立方體、 板、鱗狀物、及纖維。此處，最佳者係為具有優異光擴散特性之 球形珠。 舉例而言，功能珠15之一平均直徑可係為1〜100微米，且較佳 係為5〜50微米。在功能珠15之平均直徑處於上述範圍内之情況 下，其具有充分之擴散功能。此外，當功能珠可係為約10〜500重 量°/。時，例如當在第一 3D圖案層20中所用之樹脂係為100重量％ 時。 如第1圖及第2圖所示，第二3D圖案層30設置於第一 3D圖 案層20之一上表面，該上表面用以會聚光線，以增強亮度。第二 3D圖案層30之一下表面被造型為與第一 3D圖案層20之一上表 面實質互補，且其一上表面可具有各種3D圖案形狀。 第二3D圖案層30沿其上表面可具有一系列稜鏡圖案。舉例而 言，該稜鏡圖案可係為一線性排列之三角稜鏡圖案、一四角錐稜 鏡圖案或者一三角稜鏡圖案。呈上述稜鏡圖案之第二3D圖案層 30會提高一觀察者透過一顯示裝置所監視之影像之亮度。 如第3圖所示，一第二3D圖案層40在其一上表面上可具有一 雙凸透鏡圖案或一微透鏡圖案。具有雙凸透鏡圖案或微透鏡圖案 200914940 之第二3D圖案層40可同時包含擴散膜片之擴散功能與棱鏡膜片 之會聚功能。 如第4圖所示，一第二3D圖案層5〇於其一上表面可具有一菲 涅耳（Fresnel)圖案，該上表面上除上述圖案外亦可設置有不同 形狀之3D圖案。 如第1圖至第4圖所示，第二3D圖案層3〇、4〇及5〇可包含例 如矽酮丙烯酸酯（silicon acrylate)。倘若第二3D圖案層3〇、 及50包含矽酮丙烯酸酯，則由於矽本身之滑溜特性，表面摩擦係 數會較低，進而提供優異之可加工性’即使在其上面不形成一單 獨掩膜時亦不會損壞第二3D圖案層30、4〇及5〇之表面。 而且’即使不在第二3D圖案層30、4〇及5〇上提供一保護膜以 用於保護含矽酮丙烯酸酯之第二3D圖案層3〇、4〇及5〇及保護設 置於第二3D圖案層30、4〇及5〇上表面之顯示面板，第9圖之一 顯示面板220之一偏光膜亦不會受到損壞。 第二3D圖案層30、4〇及5〇之一折射率可高於第一犯圖案層 20之折射率，例如為丨,53或更高，且較佳係為i 54〜i 6。若第二 3D圖案層30、40及5〇之折射率小於i 53，則其應高於第一 3d 圖案層20之折射率。此乃因若第一 3D圖案層2〇之折射率高於第 二3D圖案層30、40及5〇之折射率，則入射於第一 3〇圖案層μ 背面之光線之-部分會自第二2〇圖案層3〇、4〇及5〇之表面完全 反射’而不入射於第二3D圖案層3〇、40及50之3D結構。 此外，第二3D圖案層3〇、4〇及5〇可具有約為5〜1〇〇微米之一 平均厚度。當第二3D圖案層30、40及5〇具有上述範圍之厚度時， 12 200914940 可在法線方向上有效地會聚光線。此外，儘管圖中未顯示，然而 右第3D圖案| 40及50分別具有具雙凸透鏡圖案、微透鏡圖案 或菲:¾耳圖案之上表面，則可於透明基板1〇之表面與第一扣圖 案層20之表面間增加功能珠〗5。 以下亦參照第5圖至第8圖說明根據本發明另一實施例之光學 、片第5圖至第8圖係為剖視圖，其例示根據本發明另一實施 例之光學膜片。 根據該實把例之光學臈片14〇、15〇、16〇及削實質等同於根 據本發明上述實施例之光學膜片，只是其於一第二3〇圖案層之頂 料有—預定表面粗鱗度。因此，將著重於與上文參照第】圖至 第4圖所述之本發明實施例之光學膜片之不同點來說明根據本發 明該實施例之光學膜片。 如第5圖所示，根據本發明該實施例之光學膜片140包含-透 月基板10、一第二3D圖案層2〇及一第二3D圖案層6〇。此外， 一功能珠15可夾置於透明基板與第一 3D圖案層20之一表面 間如第6圖所不。透明基板1〇、功能珠15及第一 3d圖案層別 實質等同於根據本發明上述實施例之第i圖所示光學膜片ι〇〇中 之對應者。故不再予以贅述。 -用於會聚光線以增強亮度之第三3D _案層6〇設置於第一扣 θ ”曰20之上表面。第二3D圖案層60之一下表面與第__3D i案層20之一上表面之形狀實質互補，且其一上表面可在其頂部 ”有具—預定表面粗糙度之各種3D圖案。 如第5圖及第6圖所示，第二3D圖案層⑼在其頂部可具有一 13 200914940 系列具一預定表面粗糙度之稜鏡圖案。可例如藉由研磨而在第二 3D圖案層60之頂部提供該表面粗糙度。第二3D圖案層60在其 上表面具有具預定表面粗糙度之稜鏡圖案會增強一觀察者透過一 顯示裝置所監視之影像之亮度。 如第7圖所示，一第二3D圖案層70可於其頂部設置有具一預 定表面粗糙度之一雙凸透鏡圖案或一微透鏡圖案。在其頂面上設 置有具一預定表面粗糙度之雙凸透鏡圖案或微透鏡圖案之第二3D 圖案層70可同時包含例如一擴散膜片之擴散功能與一稜鏡之會聚 功能。 如第8圖所示，一第二3D圖案層70可於其一上表面具有一具 一預定表面粗糙度之菲涅耳圖案，該上表面除上述圖案外，亦可 設置有具一預定表面粗糙度的各種形狀之3D圖案。 如第5圖至第8圖所示，在上表面具有各種形狀之預定表面粗 糙度3D圖案之第二3D圖案層60、70及80之表面粗糙度具有例 如約為0.05〜0.5微米之範圍。當第二3D圖案層60、70及80具有 上述表面粗糙度範圍時，該等表面可具有一優異之會聚力，且不 會被其他相鄰表面損壞。 而且，第二3D圖案層60、70及80中具該表面粗糙度之一面積 相對於3D圖案之一總面積之比可例如約為0.01〜10°/。。當第二3D 圖案層60、70及80中具該表面粗糙度之面積之比處於上述範圍 時，具該表面粗糙度之表面可具有優異之會聚力，且不會被其他 相鄰表面損壞。 具一預定表面粗糙度之第二3D圖案層60、70及80可增強光擴 14 200914940 散效率，乃因透過透明基板10之一背面入射之光線在透過第二犯 圖案層60、70及80向外射出時會被該表面粗糙度所形成之細微 凹凸不平所均勻擴散。 而且，類似於本發明上述實施例之光學膜片，第二3d圖案層 6〇、70及80可包含石夕酮丙稀酸醋。包含石夕酮丙稀酸醋的第二^ 圖案層60、70及80具有優異之可加工性，且具有即使在不單獨 貼附-掩臈時亦不會受職壞之表面n即使未單獨使用一 π置於第—3D圖案層6G、7G及8G上表面之保護膜來保護顯示面 板，顯示面板之一偏光膜亦不會受到損壞。 4等第一 3D圖案層60、70及80之-折射率可高於第一扣圖 案層20之折射率’例如至少為153，且較佳係為^ 6。若第 二3D圖案層60、70及80之折射率小於153，則其應高於第一 3D圖案層20之折射率。第二3D圖案層6〇、7〇及8〇可具有約為 5〜UK)微米之-平均厚度。此外，儘管圖中未顯示，然而若第二 3D圖案層70及80分別具有具雙凸透鏡圖帛、微透鏡圖案或菲涅 耳圖案之上表面，則可於透明基板1〇之表面與第一 3D圖案層2〇 之表面間增加功能珠15。 上述根據本發明另一實施例之光學膜片設置有複數個3D圖案 層，於上部3D圖案層中包含矽酮丙烯酸酯，且有選擇地具有功能 珠或表面粗糙度。因A ’該單-光學膜片可確保具有擴散功能、 會聚功能以及一保護功能。 現在’將參照第9圖來說明根據本發明—實施例之液晶顯示器。 根據本發明該實施例之一液晶顯示器2〇〇包含一背光總成 15 200914940 、一顯不面板220、上部及下部容器230及240、一中間塑膠 框（mold frame) 250 ' —下部塑膠框260、以及前罩280及後罩 290。 首先，將說明背光總成21 〇。 如第9圖所示，背光總成21〇包含：一燈單元211，用於供應光 線，一導光元件212，用於自燈單元211向上導引光線；以及一光 學膜片1〇〇，用於擴散及會聚來自導光元件212之光線。 燈單元211可包含一燈2iia及一燈反射板2nfc^舉例而言，燈 211a可係為一細長的圓柱形冷陰極熒光燈（c〇id cath〇de Flu〇rescentLamp; CCFL)e儘管圖中未顯示，然而燈以^可例如 係為一平面型熒光燈。於此種情形中，可省卻導光元件212。燈反 射板211b將來自燈2Ua之光線朝導光元件212側反射。 燈單元211可設置於導光元件212之二側上，或者儘管圖中未 顯不，燈單元211亦可設置於導光元件212之其中—側上。當燈 單元211係設置於導光元件212之二側上時，導光元件212之一 形狀可係為-平面類型之形狀。反之，若燈單元211係設置於導 光凡件212之其中—側上，則導光元件212可具有一楔形形狀。 導光元件212係由一基於塑膠之材料（例如壓克力）形成，且 在其-下表面可印刷有各種圖案，以將入射至導光元件212内側 之光線之前進方向朝顯示面板22〇側移動。 —反射板213言史置於導光元件212之一背面上，以將出射至導 光π件212之一背面之光線朝其一上表面側反射。反射板Μ]能 降低入射至顯示面22G <光線之損耗，並同時增強傳遞至導光 16 200914940 元件212上表面之光線之一致性。 設置於導光元件212上表面之光學膜片1〇〇包含一第一 3D圖案 層20及一第二3D圖案層30，依序設置於一透明基板10上。光 學膜片100可更具有位於透明基板1〇與第一 3D圖案層2〇之間的 功能珠15。此外，光學膜片1〇〇可於一第二3D圖案層4〇之頂部 具有一預定表面粗糙度。 光學膜片100沿垂直於顯示面板22〇之一方向折射及會聚透過 導光元件212射出之光線，並擴散所形成之光線，以增強光線之 亮度一致性、增大視角、並隱藏導光元件212之圖案。而且，光 學膜片100於第二3D圖案層30中包含矽酮丙烯酸酯，以便即使 在不單獨使用一掩膜或保護膜時光學膜片10之表面及相鄰部件之 表面亦不會受到損壞。 顯然，除上述光學膜片100外，亦可為背光總成21〇提供根據 本發明任-實施例之光學膜#110、120、13〇、140、15〇、16〇及 170。 用於顯示影像之顯示面板220係設置於如上文所述形成之背光 總成21〇之一上表面。顯示面板22〇包含：一第一顯示板221，具 有-濾光片，該濾光片藉由被一黑色基質所環繞之紅色、綠色及 藍色畫素使背光總成21G所供應之光、線呈現—預定顏色；一第二 顯示板222,具有排列成一矩陣之薄臈電晶體；以及一液晶層（圖 未示），形成於第一顯示板221與第二顯示板222之間。 除第-顯示板221及第二顯示板222之外，顯示面板22〇亦包 含資料及閘極印刷電路板225及226。資料及間極印刷電路板奶 17 200914940 及226係利用屬於一種撓性電路板的資料及閘極捲帶式封裝（tape carrier package ) 223及224連接至顯示面板220。此外’資料及閘 極印刷電路板225及226供應一驅動信號及一定時信號至薄膜電 晶體之一閘極線及一資料線，以控制液晶之一陣列角度以及構成 液晶層之液晶之排列週期。 儘管圖未示，然而一偏光板被設置至顯示面板220之一側，與 背光總成210相對。 上部容器230藉由裝備中間塑膠框250而固定顯示面板220,且 具有複數個耦合視窗（圖未示），中間塑膠框250利用一耦合裝置 (例如螺釘）安裝於下部容器240之上側。 下部容器240容納背光總成210,且其造型使背光總成210以例 如一矩形形狀牢牢地放置於其上面。一螺釘槽（圖未示）形成於 下部容器240之一背面上。 下部塑膠框260容置下部容器240，且複數個耦合凸起部（圖未 示）形成於下部塑膠框260之一側壁上，該複數個耦合凸起部用 於與上部容器230中所形成之耦合視窗（圖未示）相扣合。印刷 電路板罩270利用耦合裝置（例如螺釘）接地至下部容器240,以 阻擋在資料印刷電路板225中產生之短路及電波。 儘管上文係參照本發明之實例性實施例來具體顯示及說明本發 明，然而此項技術中之通常技術者將理解，在不背離由下文申請 專利範圍所界定之本發明精神及範疇之條件下，亦可在形式及細 節上對其作出各種改動。 根據本發明，在如上所述之光學膜片、以及包含該光學膜片之 18 200914940 背光總成及液晶顯示器中，—單一 早光學膜片具有反光性、平伞w 及擴散性之多種功能，且既不需 Λ m 要掩膜也不⑥要保護膜，故而在 成本降低、生產率及可加工性方 甶非㊉優異，同時可達成更輕、 更薄、更簡單且更小之液晶顯示器。 【圖式簡單說明】 藉由參照附圖詳細說明本發明之實例性實施例，本發明之上述 及其他特徵及優點將變得更加一目了然，附圖中： f 第1圖至第4圖係為剖視圖，其例示根據本發明一實施例之光 學膜片； 第5圖至第8圖係為剖視圖，其例示根據本發明另一實施例之 光學膜片；以及 第9圖係為一分解透視圖，其例示根據本發明一實施例之液晶 顯示器。 【主要元件符號說明】 透明基板 2〇 :第一 3D圖案層 40 :第二3D圖案層 60 :第二3D圖案層 80 :第二3D圖案層 110 :光學膜片 130 :光學膜片 150 :光學膜片 170 :光學膜片 15 ： 功能珠 30 ： 弟一 3D圖案層 50 ： 第二3D圖案層 70 ： 第一 3D圖案層 100 :光學膜片 120 :光學膜片 140 :光學膜片 160 :光學膜片 200 •液晶顯不器 19 200914940 210 :背光總成 211a :燈 212 :導光元件 220 :顯示面板 222 :第二顯示板 224 :閘極捲帶式封裝 226 :閘極印刷電路板 240 :下部容器 260 :下部塑膠框 280 :前罩 211 :燈單元 211b :燈反射板 213 :反射板 221 :第一顯示板 223 :資料捲帶式封裝 225 :資料印刷電路板 230 :上部容器 250 :中間塑膠框 270 :印刷電路板罩 290 :後罩 20The display panel '. and the f-light assembly as described in claim 16 are for providing the light to the display panel. In the optical film according to the present invention as described above, and the backlight assembly including the optical film and the liquid crystal display n-piece, the single-optical (four) has various functions of domain, condensing, and diffusing' and There is no need for a mask or a protective film, so it is excellent in terms of cost reduction, productivity, and maintainability. (4) A liquid crystal display that is lighter, thinner, simpler, and smaller can be achieved. [Embodiment] Embodiments of the present invention will be described in detail in the following detailed description and the accompanying drawings. The embodiments of the present invention will be described more fully hereinafter with reference to the appended claims. However, the present invention may be embodied in a number of different forms and should not be construed as limited to the details described herein: instead, the embodiments are intended to provide a thorough and complete disclosure of the present disclosure. Fully convey the invention _. The invention is defined solely by the definitions set forth in the scope of the patent application. In this specification, the same reference numerals are used to refer to the same elements. 200914940 Hereinafter, a diaphragm according to an embodiment of the present invention will be described with reference to FIGS. 4 to 4. Light Figures 1 through 4 are cross-sectional views illustrating an optical film according to an embodiment of the present invention. The optical films 1 〇〇, 110, 12 〇 and 13 该 according to this embodiment of the present invention have a protective function to prevent the optical film, in addition to the light diffusing function and the convergence work of diffracting and concentrating the light to a higher brightness. Other components in the vicinity of the sheets 100, 110, 丨 20 and 130 cause scratches. As shown in Fig. 1, the optical film 100 may include a transparent substrate 1 and a plurality of (hereinafter referred to as "3D") pattern layers 20 and 30. Preferably, a first 3D pattern layer 20 and a second 3D pattern layer 3 are provided on one side of the transparent substrate 10. First, the transparent substrate 10 is shaped as a board formed of a colorless transparent synthetic resin to allow Light transmission. The synthetic resin forming the transparent substrate 1 is not particularly limited but may be contained, for example, polyethylene-terephthalate, polyethylene naphthalate (polyethylene) -naphthalate), acrylresin, polycarbonate, polysthylene, polyolefine, cellous acetate, poly vinyl chloride. Among these materials, polyethylene terephthalate or polycarbonate having excellent transparency and high strength characteristics, and polyethylene terephthalate having an enhanced warpage efficiency are more preferable. The thickness of the transparent substrate 10 is not particularly limited, but may be, for example, 10 to 1000 μm, and preferably 25 to 600 μm. The transparent substrate 10 has excellent mechanical strength and thermal stability, and has an appropriate flexibility, and the first 3D pattern layer 20 is disposed on the transparent substrate 1 at the thickness of the thickness (4). The 3D pattern layer 20 for diffusing light can be roughened by forming a relief. The protrusions of the first 3D pattern layer and the grain shape may be shaped in different manners such as a convex red-elliptical body, a square pyramid, and a fiber, but the present invention is not limited to this shape. The material constituting the 3D pattern layer 20 is not limited, but may be, for example, acrylic resin, poly(p() lyurethane), poly vinegar (ρ〇ι purchased small gas US resin, Shi Xiji resin) Polyamide amine (p〇) yamideimide, epoxy tree UV curing resin. Therefore, 'the above-mentioned polymer can be used, or at least two of them can be mixed. In addition to the polymer, the first A pattern layer can be made up of eight or more fine inorganic or organic fillers, - hardeners, plasticizers, various leveling agents, light absorbers, anti-oxidants, - dryness and light stabilizers. The first 3D material has a relatively low refractive index, for example, a refractive index of (5) fold = and the car is better than ~ (5). The first 3D pattern layer 2 has a relatively low refractive index 'to make the self-light guide plate A large amount of light is diffused upward in the emitted light. The pattern layer 20 may have an average thickness of about 5·1 〇〇 micrometer. The error is formed by forming the -3D pattern (4) 20 to have the above thickness direction. Riding the New York. Paying for the money' as shown in Figure 2, the function beads 15 w + 3D_S special 15 can be clipped Placed between the transparent substrate Η) and the surface of the -2G. At this time, placing the functional beads between the transparent substrate 10 200914940 and the surface of the first 3D pattern layer 20 includes the following two cases: the functional beads 15 are brought into contact with the transparent substrate 10, and the functional beads 15 are separated from the transparent substrate 10 ( Although the figure is not shown). The functional bead 15 can be, for example, a light diffusing bead to enhance the light diffusing function. When the functional bead 15 is a light diffusing bead, the light transmitted from the transparent substrate 1 to the first 3D pattern layer 20 can be uniformly diffused. When the functional beads 15 are light diffusing beads, the light diffusing beads may be an inorganic filler or an organic filler. The inorganic filler may include, for example, silica, aluminum hydroxide, aluminum oxide, zinc oxide, barium sulfide, alumite, carbonic acid, and titanium oxide, so that one of the above inorganic fillers may be used or may be mixed therein. At least two. The organic filler may be a multi-layered multi-component base particle formed by covering another monomer after forming an acrylic-based fine particle of a homopolymer or a copolymer of the following substance: urethane, nylon, Shi Xi, Melamin-forumaldehyde, benzoguanamine-forumaldehyde, methyl methacrylate, acrylic acid, methatrile acid, methyl acrylate acid (hydroxyethyl-) Methacrylate ), hydroxypropyl-methacrylate, acrylamide, methylolacrylamide, glycidyl-methacrylate, Ethyl acrylate, isobutyl acrylate, normalbutyl acrylate, and 2-ethylhyxylacrylate; olefin-based particles, such as polyethylene, polysthylene, and Polypropylene; and acrylic acid and olefin-based copolymer microparticles and homopolymer microparticles. 200914940 It will be readily understood by those of ordinary skill in the art that the inorganic or organic fillers used as light diffusing beads described above are for illustrative purposes only and may be replaced by another conventional one which is cost effective to the primary object of the invention. Materials, not just inorganic or organic fillers. The functional beads 15 have a monodisperse and polydisperse particle distribution, the shape of which is not particularly limited, and can be shaped into a sphere, a spindle, a needle, a rod, a cube, a plate, a scale, and a fiber. Here, the best one is a spherical bead having excellent light diffusion characteristics. For example, one of the functional beads 15 may have an average diameter of from 1 to 100 μm, and preferably from 5 to 50 μm. In the case where the average diameter of the functional beads 15 is within the above range, it has a sufficient diffusion function. In addition, when the functional beads can be about 10 to 500 weights /. For example, when the resin used in the first 3D pattern layer 20 is 100% by weight. As shown in Figures 1 and 2, the second 3D pattern layer 30 is disposed on an upper surface of the first 3D pattern layer 20 for concentrating light to enhance brightness. The lower surface of one of the second 3D pattern layers 30 is shaped to be substantially complementary to the upper surface of one of the first 3D pattern layers 20, and an upper surface thereof may have various 3D pattern shapes. The second 3D pattern layer 30 may have a series of meandering patterns along its upper surface. For example, the 稜鏡 pattern may be a linearly arranged triangular 稜鏡 pattern, a quadrangular pyramid mirror pattern or a triangular 稜鏡 pattern. The second 3D pattern layer 30 in the above-described 稜鏡 pattern enhances the brightness of an image that is monitored by an observer through a display device. As shown in Fig. 3, a second 3D pattern layer 40 may have a lenticular lens pattern or a microlens pattern on an upper surface thereof. The second 3D pattern layer 40 having the lenticular pattern or the microlens pattern 200914940 can simultaneously include the diffusion function of the diffusion film and the convergence function of the prism film. As shown in Fig. 4, a second 3D pattern layer 5 may have a Fresnel pattern on one of its upper surfaces, and a 3D pattern of a different shape may be provided on the upper surface in addition to the above pattern. As shown in Figures 1 to 4, the second 3D pattern layers 3, 4 and 5 may comprise, for example, silicon acrylate. If the second 3D pattern layers 3, and 50 contain an fluorenone acrylate, the surface friction coefficient will be lower due to the slippery nature of the ruthenium itself, thereby providing excellent processability even if a separate mask is not formed thereon. The surface of the second 3D pattern layers 30, 4, and 5 is also not damaged. And 'even if a protective film is not provided on the second 3D pattern layers 30, 4, and 5, for protecting the second 3D pattern layer 3〇, 4〇, and 5〇 containing the fluorenone acrylate, and the protection is provided in the second The display panel of the upper surface of the 3D pattern layer 30, 4 〇 and 5 ,, one of the display panels of FIG. 9 shows that the polarizing film of one of the panels 220 is not damaged. The refractive index of one of the second 3D pattern layers 30, 4, and 5 may be higher than the refractive index of the first pattern layer 20, for example, 丨, 53 or higher, and is preferably i 54 to i 6 . If the refractive index of the second 3D pattern layers 30, 40 and 5 is less than i 53, then it should be higher than the refractive index of the first 3d pattern layer 20. Therefore, if the refractive index of the first 3D pattern layer 2〇 is higher than the refractive index of the second 3D pattern layer 30, 40, and 5〇, the portion of the light incident on the back surface of the first 3〇 pattern layer μ will be from the first The surface of the 2 〇 pattern layer 3 〇, 4 〇 and 5 完全 is completely reflected 'not incident on the 3D structure of the second 3D pattern layers 3 〇, 40 and 50. Further, the second 3D pattern layers 3, 4, and 5 may have an average thickness of about 5 to 1 〇〇 micrometer. When the second 3D pattern layers 30, 40, and 5 have a thickness in the above range, 12 200914940 can effectively converge light in the normal direction. In addition, although not shown in the figure, the right 3D patterns | 40 and 50 respectively have a lenticular lens pattern, a microlens pattern or a phenanthrene: 3⁄4 ear pattern upper surface, and the surface of the transparent substrate 1 与 and the first buckle A function bead 5 is added between the surfaces of the pattern layer 20. 5 to 8 are views, respectively, showing an optical sheet according to another embodiment of the present invention, and Figs. 5 to 8 are cross-sectional views illustrating an optical film according to another embodiment of the present invention. The optical cymbal 14 〇, 15 〇, 16 〇 and shaving according to the actual example are substantially equivalent to the optical film according to the above embodiment of the present invention, except that the top surface of the second 〇 pattern layer has a predetermined surface Thick scale. Accordingly, the optical film according to this embodiment of the present invention will be described focusing on differences from the optical film of the embodiment of the present invention described above with reference to Figs. 4 to 4. As shown in Fig. 5, the optical film 140 according to this embodiment of the present invention comprises a vapor-permeable substrate 10, a second 3D pattern layer 2A, and a second 3D pattern layer 6A. Further, a functional bead 15 can be sandwiched between the transparent substrate and one of the surfaces of the first 3D pattern layer 20 as shown in Fig. 6. The transparent substrate 1 , the functional beads 15 and the first 3d pattern layer are substantially equivalent to the counterparts in the optical film ι 第 according to the above-described embodiment of the present invention. Therefore, it will not be repeated. a third 3D layer 6 for collecting light to enhance brightness is disposed on the upper surface of the first buckle θ 曰 20. One of the lower surface of the second 3D pattern layer 60 and one of the __3D i layer 20 The shape of the surface is substantially complementary, and an upper surface thereof may have a variety of 3D patterns of predetermined surface roughness at its top. As shown in Figures 5 and 6, the second 3D pattern layer (9) may have a 13 200914940 series of ruthenium patterns having a predetermined surface roughness. The surface roughness can be provided on top of the second 3D pattern layer 60, for example by grinding. The second 3D pattern layer 60 having a predetermined surface roughness on its upper surface enhances the brightness of an image that is observed by an observer through a display device. As shown in Fig. 7, a second 3D pattern layer 70 may be provided on its top with a lenticular lens pattern or a microlens pattern having a predetermined surface roughness. The second 3D pattern layer 70 provided on the top surface thereof with a lenticular lens pattern or a microlens pattern having a predetermined surface roughness can simultaneously contain, for example, a diffusion function of a diffusion film and a convergence function. As shown in FIG. 8, a second 3D pattern layer 70 may have a Fresnel pattern having a predetermined surface roughness on an upper surface thereof, and the upper surface may be provided with a predetermined surface in addition to the pattern. A 3D pattern of various shapes of roughness. As shown in Figs. 5 to 8, the surface roughness of the second 3D pattern layers 60, 70 and 80 having a predetermined surface roughness 3D pattern of various shapes on the upper surface has a range of, for example, about 0.05 to 0.5 μm. When the second 3D pattern layers 60, 70, and 80 have the above-described range of surface roughness, the surfaces may have an excellent converging force and are not damaged by other adjacent surfaces. Moreover, the ratio of the area of one of the surface roughnesses of the second 3D pattern layers 60, 70 and 80 to the total area of one of the 3D patterns may be, for example, about 0.01 to 10 °/. . When the ratio of the area of the second 3D pattern layers 60, 70, and 80 having the surface roughness is in the above range, the surface having the surface roughness can have excellent converging force without being damaged by other adjacent surfaces. The second 3D pattern layers 60, 70, and 80 having a predetermined surface roughness can enhance the dispersion efficiency of the light diffusion 14 200914940 because the light incident through the back surface of the transparent substrate 10 passes through the second pattern layer 60, 70, and 80. When it is emitted outward, it is uniformly diffused by the unevenness of the surface roughness. Moreover, similar to the optical film of the above embodiment of the present invention, the second 3d pattern layers 6?, 70 and 80 may comprise linaloacetic acid vinegar. The second pattern layers 60, 70, and 80 containing the sulphuric acid vinegar have excellent workability, and have a surface n which is not damaged even when not separately attached-masked, even if not separately The display panel is protected by a protective film placed on the upper surface of the 3D pattern layers 6G, 7G, and 8G, and the polarizing film of one of the display panels is not damaged. The refractive index of the first 3D pattern layers 60, 70, and 80 may be higher than the refractive index of the first pattern layer 20, for example, at least 153, and is preferably ^6. If the refractive indices of the second 3D pattern layers 60, 70 and 80 are less than 153, they should be higher than the refractive index of the first 3D pattern layer 20. The second 3D pattern layers 6〇, 7〇 and 8〇 may have an average thickness of about 5 to UK) microns. In addition, although not shown in the drawing, if the second 3D pattern layers 70 and 80 respectively have a lenticular lens pattern, a microlens pattern or a Fresnel pattern upper surface, the surface of the transparent substrate 1 can be first and Functional beads 15 are added between the surfaces of the 3D pattern layer 2 . The above optical film according to another embodiment of the present invention is provided with a plurality of 3D pattern layers containing an fluorenone acrylate in the upper 3D pattern layer, and optionally having functional beads or surface roughness. Because of the A' single-optical diaphragm, it has a diffusion function, a convergence function, and a protection function. A liquid crystal display according to the present invention will now be described with reference to Fig. 9. According to the embodiment of the present invention, the liquid crystal display 2 includes a backlight assembly 15 200914940, a display panel 220, upper and lower containers 230 and 240, and an intermediate plastic frame 250' - a lower plastic frame 260. And a front cover 280 and a rear cover 290. First, the backlight assembly 21 将 will be explained. As shown in FIG. 9, the backlight assembly 21A includes: a lamp unit 211 for supplying light, a light guiding member 212 for guiding light upward from the lamp unit 211, and an optical film 1〇〇, For diffusing and concentrating light from the light guiding element 212. The lamp unit 211 can include a lamp 2iia and a lamp reflector 2nfc. For example, the lamp 211a can be an elongated cylindrical cold cathode fluorescent lamp (CCFL), although not shown in the figure. Displayed, however, the lamp can be, for example, a flat fluorescent lamp. In this case, the light guiding element 212 can be omitted. The lamp reflecting plate 211b reflects the light from the lamp 2Ua toward the light guiding element 212 side. The lamp unit 211 may be disposed on both sides of the light guiding member 212, or the lamp unit 211 may be disposed on the side of the light guiding member 212, although not shown. When the lamp unit 211 is disposed on both sides of the light guiding member 212, one of the light guiding members 212 may be shaped like a plane type. On the other hand, if the lamp unit 211 is disposed on the side of the light guide member 212, the light guiding member 212 may have a wedge shape. The light guiding member 212 is formed of a plastic-based material (for example, acryl), and various patterns can be printed on the lower surface thereof to advance the light incident on the inner side of the light guiding member 212 toward the display panel 22. Side movement. The reflecting plate 213 is placed on the back surface of one of the light guiding elements 212 to reflect the light emitted to the back surface of one of the light guiding members 212 toward the upper surface side thereof. The reflector Μ] reduces the loss of light incident on the display surface 22G <RTIgt;</RTI> and simultaneously enhances the uniformity of light transmitted to the upper surface of the component 212. The optical film 1A disposed on the upper surface of the light guiding element 212 includes a first 3D pattern layer 20 and a second 3D pattern layer 30, which are sequentially disposed on a transparent substrate 10. The optical film 100 may further have functional beads 15 between the transparent substrate 1 and the first 3D pattern layer 2''. Further, the optical film 1 may have a predetermined surface roughness on top of a second 3D pattern layer 4''. The optical film 100 refracts and condenses light emitted through the light guiding element 212 in a direction perpendicular to one direction of the display panel 22, and diffuses the formed light to enhance the brightness uniformity of the light, increase the viewing angle, and hide the light guiding element. 212 pattern. Moreover, the optical film 100 contains an fluorenone acrylate in the second 3D pattern layer 30 so that the surface of the optical film 10 and the surface of the adjacent member are not damaged even when a mask or a protective film is not used alone. . It is apparent that in addition to the optical film 100 described above, the optical films #110, 120, 13A, 140, 15A, 16A and 170 according to any of the embodiments of the present invention may be provided for the backlight assembly 21A. The display panel 220 for displaying an image is disposed on one of the upper surfaces of the backlight assembly 21 formed as described above. The display panel 22A includes a first display panel 221 having a filter that supplies the backlight assembly 21G with light by red, green, and blue pixels surrounded by a black matrix. The line presents a predetermined color; a second display panel 222 having a thin germanium transistor arranged in a matrix; and a liquid crystal layer (not shown) formed between the first display panel 221 and the second display panel 222. In addition to the first display panel 221 and the second display panel 222, the display panel 22A also includes data and gate printed circuit boards 225 and 226. Data and Interpolar Printed Circuit Board Milk 17 200914940 and 226 are connected to display panel 220 using data and gate carrier packages 223 and 224 belonging to a flexible circuit board. In addition, the data and gate printed circuit boards 225 and 226 supply a driving signal and a timing signal to one of the gate lines and a data line of the thin film transistor to control the array angle of the liquid crystal and the arrangement period of the liquid crystals constituting the liquid crystal layer. . Although not shown, a polarizing plate is disposed to one side of the display panel 220 opposite to the backlight assembly 210. The upper container 230 is fixed to the display panel 220 by being equipped with an intermediate plastic frame 250, and has a plurality of coupling windows (not shown). The intermediate plastic frame 250 is mounted on the upper side of the lower container 240 by a coupling device (for example, a screw). The lower container 240 houses the backlight assembly 210 and is shaped such that the backlight assembly 210 is firmly placed thereon, for example, in a rectangular shape. A screw groove (not shown) is formed on the back surface of one of the lower containers 240. The lower plastic frame 260 houses the lower container 240, and a plurality of coupling protrusions (not shown) are formed on one side wall of the lower plastic frame 260, and the plurality of coupling protrusions are formed in the upper container 230. The coupling window (not shown) is engaged. The printed circuit board cover 270 is grounded to the lower container 240 by means of coupling means (e.g., screws) to block short circuits and electric waves generated in the data printed circuit board 225. Although the present invention has been specifically shown and described with reference to the exemplary embodiments of the present invention, it will be understood by those skilled in the art In the following, various changes can be made in the form and details. According to the present invention, in the optical film as described above, and the 18 200914940 backlight assembly and the liquid crystal display including the optical film, the single early optical film has various functions of light reflection, flat umbrella w and diffusibility. There is no need to cover the film or protect the film, so the cost reduction, productivity and processability are not excellent, and a lighter, thinner, simpler and smaller liquid crystal display can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will become more apparent from the detailed description of exemplary embodiments of the invention. A cross-sectional view illustrating an optical film according to an embodiment of the present invention; FIGS. 5 to 8 are cross-sectional views illustrating an optical film according to another embodiment of the present invention; and FIG. 9 is an exploded perspective view A liquid crystal display according to an embodiment of the present invention is exemplified. [Description of Main Element Symbols] Transparent Substrate 2: First 3D Pattern Layer 40: Second 3D Pattern Layer 60: Second 3D Pattern Layer 80: Second 3D Pattern Layer 110: Optical Film 130: Optical Film 150: Optical Diaphragm 170: Optical film 15: Functional bead 30: Brother-3D pattern layer 50: Second 3D pattern layer 70: First 3D pattern layer 100: Optical film 120: Optical film 140: Optical film 160: Optical Diaphragm 200 • Liquid crystal display 19 200914940 210 : Backlight assembly 211a : Lamp 212 : Light guiding element 220 : Display panel 222 : Second display panel 224 : Gate tape and reel package 226 : Gate printed circuit board 240 : Lower container 260: lower plastic frame 280: front cover 211: lamp unit 211b: lamp reflector 213: reflector 221: first display panel 223: data tape package 225: data printed circuit board 230: upper container 250: middle Plastic frame 270: printed circuit board cover 290: rear cover 20