200839301 九、發明說明： 【發明所屬之技術領域】 本發明涉及一種導光板及其製備方法，尤其涉及一種用 於侧置式背光模組之導光板及其製備方法。 【先前技術】 由於液晶顯示器面板之液晶本身不具發光特性，故，爲 達到顯示效果，需給液晶顯示器面板提供一面光源裝置，如 背光模組，其作用在於向液晶顯示器面板供應亮度充分並且 分佈均勻之面光源。 請參閱圖1，一種採用習知導光板之侧置式背光模組 10,其包括導光板11、光源13、反射板15、擴散片17與棱 鏡片19。導光板11包括一出光面112、一與出光面112相 對之底面114及連接出光面112與底面114之入光面116。 導光板11之底面114形成有複數半球狀凸起之微結構118， 且該微結構118之表面爲鏡面。光源13設置於入光面116 並可將光線發射至導光板11。反射板15設置於導光板11 之底面114下方。擴散片17與棱鏡片19依次設置於導光板 11之出光面112上侧。導光板11之作用在於藉由複數微結 構118之作用破壞光線之全反射條件，以引導光線傳輸方 向，使光線由導光板11之出光面112均勻出射。反射板15 可將從導光板11之底面114出射之光線再次反射入導光板 11内，提高光線之利用率。擴散片17與棱鏡片19可使從導 光板11出射之光線具有更好之均勻性與亮度，進而提高液 晶顯示器面板之亮度與均勻性。 6 200839301 惟，由於導光板11之微結構Π8之表面爲鏡面，光線 到達微結構118時發生鏡面反射，鏡面反射可使得從導光板 11出射之光線具有較佳之視角收斂性，但出光均勻性較差。 請參閱圖2，爲改善上述導光板11出射光線均勻性較 差之缺點，習知技術另提供一種導光板21。導光板21與上 述導光板11相似，其不同係將微結構218之表面設置爲粗 糙面。這樣，光到達粗糙面發生漫反射，因而使得從導光板 21之出光面212出射之光線具有較好之均勻性。但漫反射同 時也會使得從導光板21之出光面212出射之光線之出射角 度較大，視角收斂性較差，從而導致從導光板21之出光面 212出射之光之強度較低。 【發明内容】 鑒於上述狀況，有必要提供一種同時具有較好視角收斂 性與出光均勻性之導光板及其製備方法。 一種導光板，其包括一出光面、一與該出光面相對之底 面及至少一連接該出光面與該底面之入光面，該底面形成複 數微結構，每個微結構包括鏡面部與粗糙面部，該鏡面部可 將投射到其上之光線鏡面反射，該粗糙面部可將投射到其上 之光線漫反射。 一種導光板製備方法，其包括以下步驟：加熱透明樹脂 以形成溶融導光板材料，將溶融導光板材料注入一射出成型 模具之模具模腔内，模具模腔至少一内壁形成有複數微結 構，且每一微結構包括鏡面部與粗糙面部；於模具模腔内固 化溶融導光板材料以形成導光板，該導光板之其中一表面形 7 200839301 成複數微結構，每一微結構包括鏡面部與粗糙面部。 一種導光板製備方法，其包括以下步驟：提供一透明塑 膠基板與一熱壓成型模具，該熱壓成型模具包括一模板，該 模板之一表面上形成有複數微結構，且每一微結構包括鏡面 部與粗糙面部；加熱透明塑膠基板使其軟化；模板形成有複 數微結構之表面與透明塑膠基板之一表面接觸並藉由模板 向塑膠基板施加一定壓力，以使得透明塑膠基板之表面形成 複數微結構，每一微結構包括鏡面部與粗糙面部；冷卻透明 塑膠基板製得導光板。 與習知技術相比較，所述導光板具有以下優點：導光板 之底面形成複數微結構，每個微結構包括鏡面部與粗糙面 部，鏡面部使得經過導光板之光線具有一定之視角收斂，粗 糙面部使得經過導光板之光線具有較好之均勻性，從而有效 提高整個導光板之視角收斂與出光均勻性。 【實施方式】 下面將結合附圖與複數實施例對本發明之導光板及製 備方法作進一步之詳細說明。 請一併參閱圖3與圖4，本發明較佳實施例一提供一種 導光板30。導光板30呈四方形，其包括一出光面312、一 與出光面312相對之底面314及連接出光面312與底面314 之四個入光面316。底面314形成有複數形狀相同之微結構 318，該微結構318爲棱台形凸起。複數微結構318於底面 314呈陣列排佈，且每個微結構318之端部形成表面粗糙之 粗糙面部，其侧面形成表面光滑之鏡面部。該鏡面部可將投 8 200839301 射到其上之光線鏡面反射，該粗糙面部可將投射到其上之光 線漫反射。且爲達到較佳之光學效果，該粗糙面部之面積可 爲粗糙面部與鏡面部之面積之和之30%至70%，且粗糙面部 之粗糙度大於等於0.2。可以理解，該鏡面部之面積也可爲 粗糙:面部與鏡面部之面積之和之30%至70%。 另，爲使得該導光板30具有較好之光學效果與較輕之 重量，本實施例之導光板30可選擇重量輕之透明樹脂材料 製成，如丙稀酸樹脂、聚碳酸酯、聚乙稀樹脂等。 由於導光板30之底面314形成有複數微結構318，每 個微結構318形成有鏡面部與粗糙面部，藉由鏡面部對投射 到其上之光線之鏡面反射，鏡面部使得經過導光板30之光 線具有較好之視角收斂；藉由粗糙面部對投射到其上之光線 之漫反射，粗糙面部使得經過導光板30之光線具有較好之 均勻性，從而有效提高整個導光板30之視角收斂與出光均 勻性。 可以理解，本發明之導光板也可以係五邊形、六邊形或 者其他形狀，甚至還可爲楔形。且，形成於底面之微結構也 可爲隨機排列。 請參閱圖5，本發明較佳實施例二提供一種導光板50。 該導光板50與較佳實施例一之導光板30相似，其不同在 於：導光板50之微結構518之端部形成表面光滑之鏡面部， 其侧面形成表面粗糙之粗糙面部。 請一併參閱圖6與圖7，本發明較佳實施例三提供一種 導光板60。該導光板60與較佳實施例一之導光板30相似， 200839301 其不同在於：形成於導光板60之底面614之微結構618爲 凹槽，該凹槽呈倒置棱台狀，且該凹槽之底部形成粗糙面 部，凹槽之側壁形成鏡面部。 請參閱圖8,本發明較佳實施例四提供一種導光板70。 該導光板70與較佳實施例一之導光板30相似，其不同在 於：導光板70之微結構718爲圓台形，且該微結構718之 端部形成粗糙面部，側面形成鏡面部。可以理解，粗糙面部 與鏡面部也可分別形成於微結構之侧面與端部。 請參閱圖9，本發明較佳實施例五提供一種導光板80。 該導光板80與較佳實施例一之導光板20相似，其不同在 於：導光板80呈楔形。這樣，導光板80僅具有一入光面。 可以理解，形成於導光板之底面之微結構可爲凸起或凹 槽，且其形狀除可爲棱台形與圓台形外，還可爲長條形或半 球形等其他形狀，並且，複數微結構之形狀與大小可以相 同，也可不同。鏡面部與粗糙面部於微結構上之形成位置可 作一定之變換。另，該鏡面部與粗糙面部於微結構之表面還 可爲交錯間隔排佈，無論如何，只要該微結構表面同時形成 有鏡面部與粗糙面部即可。這樣，鏡面部使得經過導光板之 光線具有較好之視角收敛’粗糖面部使得經過導光板之光線 具有較好之均勻性，從而有效提高整個導光板之視角收斂與 出光均勻性。 一種製備上述導光板30之方法，其採用射出成型模具 製備。 請參閱圖10，射出成型模具包括一第一模具301及一 200839301 第二模具303。該第一模具301具有一成型槽3011，該成型 槽3011可與該第二模具303相配合形成模具模腔。第二模 具303與第一模具301之成型槽3011相對應之區域形成有 複數凹槽狀微結構，每一微結構之形狀與上述導光板30之 底面314之微結構318形狀相對應。且每一微結構包括鏡面 部與粗糙面部，其中，鏡面部位於凹槽之侧壁，粗链面結構 位於凹槽之槽底，兩者分別用以形成導光板30之微結構318 之鏡面部與粗糙面部。 當第二模具303與第一模具301之成型槽3011相配合 形成模具模腔時，第二模具303形成有複數微結構之部分區 域成爲模具模腔之一内壁，即該内壁具有複數凹槽狀微結 構，且每一微結構包括鏡面部與粗糙面部。 製備過程中，可先加熱透明樹脂材料以形成熔融之導光 板材料’再將該溶融之導光板材料注入射出成型模具之模具 模腔，然後於模具模腔内固化熔融導光板材料以形成導光 板，該導光板之其中一表面形成複數微結構，每一微結構包 括鏡面部與粗糙面部。 爲使得射出成型模具在拆卸與組裝時較爲容易，可將第 二模具303設計爲組合形式，即第二模具303可由一基體 3031、一第一模仁3035及一第二模仁3037組合而成。基體 3031上開設有一鑲嵌槽3033，第一模仁3035及第二模仁 3037依次設置於鑲嵌槽3033内侧。第一模仁3035表面形成 有複數粗糙面區域。第二模仁3037上形成有複數棱台形通 孔，通孔侧面爲鏡面。這樣，第一模仁3035與第二模仁3037 11 200839301 相配合時，第一模仁3035之粗糙面區域分別位於第二模仁 3037之通孔之開口處以形成凹槽之粗糙面部，通孔侧面形成 凹槽之鏡面部。另，第一模仁3035之粗糙面區域可藉由機 械加工、放電加工、喷沙或化學蝕刻等方式製得，第二模仁 3037之通孔側面可藉由機械加工製得。 可以理解，於上述射出成型模具中，依據導光板之微凸 起結構之變化，射出成型模具之凹槽也可變換爲凸起等其他 結構。可以理解，複數微結構也可設置於第一模具之成型槽 之槽底。 一種製備上述導光板60之方法，其採用熱壓成型模具 製備。 請參閱圖11，熱壓成型模具包括一模板400，模板400 之一表面形成有複數棱台狀凸起之微結構405，每一微結構 405之形狀與上述導光板60之底面614之微結構618形狀相 對應，且每一微結構405形成有鏡面部與粗糙面部。其中， 粗糙面部形成於微結構405之端部，鏡面部形成於微結構 405之侧面，用以分別形成導光板30之微結構318之粗糙面 部與鏡面部。然後，將一透明塑膠基板610加熱並使其軟化， 一般加熱溫度位於相應塑膠之玻璃態轉化溫度以上。使模板 400形成有複數微結構405之表面與透明塑膠基板610之一 表面接觸並藉由模板400向透明塑膠基板610施加一定壓 力，以使得透明塑膠基板610之表面形成複數微結構，每一 結構包括鏡面部與粗糙面部。冷卻透明塑膠基板610製得導 光板60。 12 200839301 可㈣解，於上述熱壓成型模具中，依據 =之變化，熱壓成型模具之微結構也可設置爲凹槽： 綜上料，本料符合發日轉件，錢法 p ϋ上所述者僅為本發明之較佳實施例 = 本案技藝之人士 ’衫依本發明精神所作之等效修飾或、: 化，皆應涵蓋於以下之申請專利範圍内。 ^交 【圖式簡單說明】 圖1係採用習知技術導光板之背光模組之結構示音圖。 圖2係習知技術另—導光板之剖面示意圖。“ 發明較佳實施例—之㈣板立體結構示意圖。 圖4係圖3所示導光板沿㈣線之剖面示意圖。 =ίΓ較佳實施例二之導光板立體結構示意圖。 =二：明較佳實施例三之導光板立體結構示意圖。 『係圖6所示導光板沿VII_VII線之剖面示意圖。 明較佳實施例四之導光板立體結構示意圖。 難實施例五之導光板立體結構示意圖。 圖1〇係採用射出成型模具製備圖3所示導光板之示音 圖 。圖11係採用熱壓成型模具製備圖6所示導光板之示意 【主要元件符號說明 (本發明） 30 、 50 、 60 、 70 、 80 導光板 13 200839301 出光面 312 底面 314 、 614 入光面 316 微結構 318 、 518 、 618 、 718 第一模具 301 成型槽 3011 第二模具 303 基體 3031 镶彼槽 3033 第一模仁 3035 第二模仁 3037 模板 400 微結構 405 透明塑膠基板 610 (習知） 背光模組 10 導光板 11、21 出光面 112 > 212 底面 114 入光面 116 微結構 118 、 218 光源 13 反射板 15 擴散片 17 14 19 200839301 棱鏡片 15[Technical Field] The present invention relates to a light guide plate and a method of fabricating the same, and more particularly to a light guide plate for a side-mounted backlight module and a method of fabricating the same. [Prior Art] Since the liquid crystal of the liquid crystal display panel itself has no light-emitting characteristics, in order to achieve the display effect, a liquid crystal display device, such as a backlight module, needs to be provided to the liquid crystal display panel, and the function thereof is to supply the liquid crystal display panel with sufficient brightness and uniform distribution. Surface light source. Referring to FIG. 1, a side-mounted backlight module 10 using a conventional light guide plate includes a light guide plate 11, a light source 13, a reflection plate 15, a diffusion sheet 17, and a prism lens 19. The light guide plate 11 includes a light exit surface 112, a bottom surface 114 opposite to the light exit surface 112, and a light incident surface 116 connecting the light exit surface 112 and the bottom surface 114. The bottom surface 114 of the light guide plate 11 is formed with a plurality of hemispherical convex microstructures 118, and the surface of the microstructure 118 is a mirror surface. The light source 13 is disposed on the light incident surface 116 and can emit light to the light guide plate 11. The reflector 15 is disposed below the bottom surface 114 of the light guide plate 11. The diffusion sheet 17 and the prism sheet 19 are sequentially disposed on the upper side of the light-emitting surface 112 of the light guide plate 11. The function of the light guide plate 11 is to destroy the total reflection condition of the light by the action of the plurality of micro-structures 118 to guide the light transmission direction so that the light is uniformly emitted from the light-emitting surface 112 of the light guide plate 11. The reflector 15 can reflect the light emitted from the bottom surface 114 of the light guide plate 11 into the light guide plate 11 to improve the utilization of light. The diffuser sheet 17 and the prism sheet 19 allow the light emitted from the light guide plate 11 to have better uniformity and brightness, thereby improving the brightness and uniformity of the liquid crystal display panel. 6 200839301 However, since the surface of the microstructure Π 8 of the light guide plate 11 is a mirror surface, specular reflection occurs when the light reaches the microstructure 118. The specular reflection can make the light emitted from the light guide plate 11 have better viewing angle convergence, but the light uniformity is poor. . Referring to FIG. 2, in order to improve the shortcoming of the uniformity of the light emitted from the light guide plate 11, the prior art further provides a light guide plate 21. The light guide plate 21 is similar to the above-described light guide plate 11, and the difference is that the surface of the microstructure 218 is set to a rough surface. Thus, the light reaches the rough surface and diffusely reflects, so that the light emitted from the light exit surface 212 of the light guide plate 21 has a good uniformity. However, the diffuse reflection also causes the light emitted from the light exiting surface 212 of the light guide plate 21 to have a large angle of exit, and the viewing angle is poor, so that the intensity of the light emitted from the light exiting surface 212 of the light guide plate 21 is low. SUMMARY OF THE INVENTION In view of the above circumstances, it is necessary to provide a light guide plate having good viewing angle convergence and uniformity of light emission and a preparation method thereof. A light guide plate includes a light emitting surface, a bottom surface opposite to the light emitting surface, and at least one light incident surface connecting the light emitting surface and the bottom surface, the bottom surface forming a plurality of microstructures, each of the microstructures including a mirror surface and a rough surface The mirror face mirrors the light projected onto it, and the rough face diffuses the light projected onto it. A method for preparing a light guide plate, comprising the steps of: heating a transparent resin to form a molten light guide plate material, injecting a molten light guide plate material into a mold cavity of an injection molding die, wherein at least one inner wall of the mold cavity is formed with a plurality of microstructures, and Each of the microstructures includes a mirror surface and a rough surface; the molten light guide plate material is solidified in the mold cavity to form a light guide plate, and one of the surface shapes of the light guide plate 7 200839301 is a plurality of microstructures, each of which includes a mirror face and a rough surface Face. A method for preparing a light guide plate, comprising the steps of: providing a transparent plastic substrate and a hot press forming mold, the hot press forming mold comprising a template having a plurality of microstructures formed on one surface thereof, and each microstructure comprises The mirror surface and the rough surface; the transparent plastic substrate is heated to soften; the surface of the template formed with the plurality of microstructures is in contact with one surface of the transparent plastic substrate, and a certain pressure is applied to the plastic substrate by the template, so that the surface of the transparent plastic substrate forms a plurality Microstructure, each microstructure includes a mirror surface and a rough surface; and a transparent transparent plastic substrate to obtain a light guide plate. Compared with the prior art, the light guide plate has the following advantages: the bottom surface of the light guide plate forms a plurality of micro structures, each of the microstructures includes a mirror surface and a rough surface, and the mirror surface makes the light passing through the light guide plate have a certain angle of view convergence and roughness. The face makes the light passing through the light guide plate have better uniformity, thereby effectively improving the viewing angle convergence and the light uniformity of the entire light guide plate. [Embodiment] Hereinafter, a light guide plate and a production method of the present invention will be further described in detail with reference to the accompanying drawings and the embodiments. Referring to FIG. 3 and FIG. 4 together, a preferred embodiment of the present invention provides a light guide plate 30. The light guide plate 30 has a square shape and includes a light exit surface 312, a bottom surface 314 opposite to the light exit surface 312, and four light incident surfaces 316 connecting the light exit surface 312 and the bottom surface 314. The bottom surface 314 is formed with a plurality of microstructures 318 having the same shape, and the microstructures 318 are prismatic projections. The plurality of microstructures 318 are arranged in an array on the bottom surface 314, and the ends of each of the microstructures 318 form a rough surface having a rough surface, and the sides thereof form a mirror surface having a smooth surface. The mirror face can be specularly reflected by the light hitting it on 200839301, which diffuses the light that is projected onto it. And in order to achieve a better optical effect, the rough surface may have an area of 30% to 70% of the sum of the areas of the rough surface and the mirror surface, and the roughness of the rough surface is 0.2 or more. It can be understood that the area of the mirror face can also be rough: 30% to 70% of the sum of the area of the face and the mirror face. In addition, in order to make the light guide plate 30 have better optical effect and lighter weight, the light guide plate 30 of the embodiment can be made of a light-weight transparent resin material, such as acrylic resin, polycarbonate, and polyethylene. Dilute resin, etc. Since the bottom surface 314 of the light guide plate 30 is formed with a plurality of microstructures 318, each of the microstructures 318 is formed with a mirror surface and a rough surface. The mirror surface reflects the specular reflection of the light projected thereon, and the mirror surface passes through the light guide plate 30. The light has a good viewing angle convergence; the rough surface makes the light passing through the light guide plate 30 have better uniformity by the diffuse reflection of the light projected onto the rough surface, thereby effectively improving the viewing angle convergence of the entire light guide plate 30. Light uniformity. It will be appreciated that the light guide of the present invention may also be pentagon, hexagonal or other shape, and may even be wedge shaped. Moreover, the microstructures formed on the bottom surface may also be randomly arranged. Referring to FIG. 5, a preferred embodiment 2 of the present invention provides a light guide plate 50. The light guide plate 50 is similar to the light guide plate 30 of the preferred embodiment, except that the end portion of the microstructure 518 of the light guide plate 50 forms a mirror surface having a smooth surface, and the side surface thereof forms a rough surface having a rough surface. Referring to FIG. 6 and FIG. 7, a preferred embodiment 3 of the present invention provides a light guide plate 60. The light guide plate 60 is similar to the light guide plate 30 of the first embodiment. The difference is that the microstructure 618 formed on the bottom surface 614 of the light guide plate 60 is a groove, and the groove has an inverted prism shape, and the groove The bottom portion forms a rough surface, and the side walls of the groove form a mirror surface. Referring to FIG. 8, a preferred embodiment 4 of the present invention provides a light guide plate 70. The light guide plate 70 is similar to the light guide plate 30 of the first embodiment except that the microstructure 718 of the light guide plate 70 is in the shape of a truncated cone, and the end portion of the microstructure 718 forms a rough surface, and the side surface forms a mirror surface. It will be understood that the rough face and the mirror face may also be formed on the sides and ends of the microstructure, respectively. Referring to FIG. 9, a preferred embodiment 5 of the present invention provides a light guide plate 80. The light guide plate 80 is similar to the light guide plate 20 of the first embodiment except that the light guide plate 80 has a wedge shape. Thus, the light guide plate 80 has only one light incident surface. It can be understood that the microstructure formed on the bottom surface of the light guide plate may be a protrusion or a groove, and the shape may be other shapes such as an elongated shape or a hemispherical shape, in addition to a prismatic shape and a truncated cone shape, and a plurality of micro shapes. The shape and size of the structure may be the same or different. The formation position of the mirror surface and the rough surface on the microstructure can be changed. Further, the mirror surface and the rough surface may be arranged at a staggered interval on the surface of the microstructure, in any case, as long as the microstructure surface is simultaneously formed with a mirror surface and a rough surface. In this way, the mirror surface allows the light passing through the light guide plate to have a better viewing angle convergence. The rough sugar surface has a better uniformity of light passing through the light guide plate, thereby effectively improving the viewing angle convergence and light uniformity of the entire light guide plate. A method of preparing the above-described light guide plate 30, which is prepared by using an injection molding die. Referring to FIG. 10, the injection molding die includes a first die 301 and a 200839301 second die 303. The first mold 301 has a molding groove 3011, and the molding groove 3011 can cooperate with the second mold 303 to form a mold cavity. The region of the second mold 303 corresponding to the molding groove 3011 of the first mold 301 is formed with a plurality of groove-like microstructures each having a shape corresponding to the shape of the microstructure 318 of the bottom surface 314 of the light guide plate 30. And each of the microstructures includes a mirror surface and a rough surface, wherein the mirror surface is located on the sidewall of the groove, and the thick chain surface structure is located at the groove bottom of the groove, and the two are respectively used to form the mirror surface of the microstructure 318 of the light guide plate 30. With a rough face. When the second mold 303 cooperates with the molding groove 3011 of the first mold 301 to form a mold cavity, the second mold 303 is formed with a partial region of the plurality of microstructures as an inner wall of the mold cavity, that is, the inner wall has a plurality of grooves Microstructures, and each microstructure includes a mirror face and a rough face. During the preparation process, the transparent resin material may be heated to form a molten light guide plate material. The molten light guide plate material is injected into the mold cavity of the injection molding die, and then the molten light guide plate material is solidified in the mold cavity to form a light guide plate. One of the surfaces of the light guide plate forms a plurality of microstructures, and each of the microstructures includes a mirror surface and a rough surface. In order to make the injection molding die easier in disassembly and assembly, the second die 303 can be designed in a combined form, that is, the second die 303 can be combined by a base 3031, a first die 3035 and a second die 3037. to make. A mounting groove 3033 is defined in the base body 3031. The first mold core 3035 and the second mold core 3037 are sequentially disposed inside the mounting groove 3033. The surface of the first mold core 3035 is formed with a plurality of rough surface areas. A plurality of prismatic through holes are formed in the second mold core 3037, and the side faces of the through holes are mirror surfaces. Thus, when the first mold core 3035 is engaged with the second mold core 3037 11 200839301, the rough surface area of the first mold core 3035 is respectively located at the opening of the through hole of the second mold core 3037 to form a rough surface of the groove, the through hole The mirror surface of the groove is formed on the side. Alternatively, the rough surface area of the first mold core 3035 can be obtained by mechanical processing, electrical discharge machining, sand blasting or chemical etching, and the through hole side of the second mold core 3037 can be obtained by mechanical processing. It can be understood that in the above-mentioned injection molding die, depending on the change of the micro-convex structure of the light guide plate, the groove of the injection molding die can be converted into other structures such as projections. It will be understood that the plurality of microstructures may also be disposed at the bottom of the groove of the forming groove of the first mold. A method of preparing the above-described light guide plate 60, which is prepared by a hot press molding die. Referring to FIG. 11, the hot press molding die includes a template 400. The surface of one of the templates 400 is formed with a plurality of prismatic protrusions 405, and the shape of each microstructure 405 and the microstructure of the bottom surface 614 of the light guide plate 60. The 618 shapes correspond, and each microstructure 405 is formed with a mirror face and a rough face. Wherein, a rough surface is formed at an end of the microstructure 405, and a mirror surface is formed on a side of the microstructure 405 for respectively forming a rough surface and a mirror surface of the microstructure 318 of the light guide plate 30. Then, a transparent plastic substrate 610 is heated and softened, and the heating temperature is generally above the glass transition temperature of the corresponding plastic. The surface of the template 400 formed with the plurality of microstructures 405 is in contact with a surface of the transparent plastic substrate 610 and a certain pressure is applied to the transparent plastic substrate 610 by the template 400, so that the surface of the transparent plastic substrate 610 forms a plurality of microstructures, each structure. Includes mirror face and rough face. The light guide plate 60 is formed by cooling the transparent plastic substrate 610. 12 200839301 (4) Solution, in the above hot press forming mold, according to the change of =, the microstructure of the hot press forming mold can also be set as a groove: the top material, the material conforms to the daily transfer, the money method p ϋ The invention is only a preferred embodiment of the present invention. The equivalent modifications or modifications made by the person skilled in the art of the present invention are intended to be included in the following claims. ^交 [Simplified description of the drawings] Figure 1 is a structural diagram of the backlight module using a conventional technology light guide plate. 2 is a schematic cross-sectional view of a light guide plate according to a conventional technique. FIG. 4 is a schematic cross-sectional view of the light guide plate shown in FIG. 3 along the (four) line. FIG. 4 is a schematic view showing the three-dimensional structure of the light guide plate according to the second preferred embodiment. 3 is a schematic view showing the three-dimensional structure of the light guide plate shown in FIG. 6. A schematic view showing the three-dimensional structure of the light guide plate of the fourth embodiment. 1〇 is a sound-emitting diagram of the light guide plate shown in FIG. 3 by using an injection molding die. FIG. 11 is a schematic diagram of preparing a light guide plate shown in FIG. 6 by using a hot press molding die. [Main component symbol description (invention) 30, 50, 60 70, 80 light guide plate 13 200839301 light emitting surface 312 bottom surface 314, 614 light incident surface 316 microstructure 318, 518, 618, 718 first mold 301 molding groove 3011 second mold 303 base 3031 inlaid groove 3033 first mold core 3035 The second mold 3037 template 400 microstructure 405 transparent plastic substrate 610 (conventional) backlight module 10 light guide plate 11, 21 light emitting surface 112 > 212 bottom surface 114 into Smooth surface 116 Microstructure 118, 218 Light source 13 Reflector 15 Diffusion sheet 17 14 19 200839301 Prism sheet 15