201028744 六、發明說明： 【發明所屬之技術領域】 本發明係與導光板有關，特別是指一種透光率高且可 將光源所發出之光線均勻擴散之導光板。 【先前技術】 一般液晶顯示器所使用之背光模組主要包含有光源、 導光板、反射板、擴散板、增亮膜與偏光轉換膜，其中， 導光板主要功能在於導引光線方向，以提高面板光輝度及 控制亮度均勻，反射板係用來防止導光板底部之光線外 漏’以增加光的使用效率，擴散板之功能在使導光板射出 之光線擴散成一均勻之面光源。 傳統導光板係以射出成型的方法將聚甲基丙稀酸曱酯 (polymethyl methacrylate, PMMA)製成表面光滑的板塊，然 後用具尚反射率且不吸光的材料，在導光板底面用網版印 刷印上圓形或方形的擴散點，當光源置於導光板侧面時， 這些擴散點可將光線向上反射，使光線由導光板頂面射 出，惟由導光板頂面射出之光線未臻均勻，需透過擴散板 作用始能形成均勻面光源。 由於導光板與擴散板是影響背光模組光效率的重要元 件，已成為業界長期以來亟待研發改良之標的。 【發明内容】 本發明之一目的在於提供一種導光板，其透光率高， 3 201028744 同時可將光源所發出之光線均勻擴散。 為達成前揭目的，本發明所提供之導光板係包含有一 基材與多數反射微粒’該基材係由熱塑性塑膠所製成，該 等反射微粒係散佈於該基材中，其平均粒徑為 0·1μιη〜ΙΟΟμιη’該等反射微粒分別具有一核心與一殼層， 該殼層係由 Α12〇3、Β2〇3、BaC03、Bi2〇3、CaC03、Ce02、201028744 VI. Description of the Invention: [Technical Field] The present invention relates to a light guide plate, and more particularly to a light guide plate having a high light transmittance and uniformly diffusing light emitted from a light source. [Prior Art] A backlight module used in a general liquid crystal display mainly includes a light source, a light guide plate, a reflection plate, a diffusion plate, a brightness enhancement film, and a polarization conversion film. The main function of the light guide plate is to guide the light direction to improve the panel. The brightness and the control brightness are uniform, and the reflection plate is used to prevent the light leakage at the bottom of the light guide plate to increase the use efficiency of the light. The function of the diffusion plate diffuses the light emitted from the light guide plate into a uniform surface light source. Conventional light guide plates are made of polymethyl methacrylate (PMMA) into a smooth surface by injection molding, and then screened on the bottom surface of the light guide plate with a material that is still reflective and non-absorbent. A circular or square diffusion point is printed. When the light source is placed on the side of the light guide plate, the diffusion points can reflect the light upward, so that the light is emitted from the top surface of the light guide plate, but the light emitted from the top surface of the light guide plate is not evenly distributed. A uniform surface light source can be formed by the action of the diffusion plate. Since the light guide plate and the diffusion plate are important elements affecting the light efficiency of the backlight module, it has become an object of improvement for the industry for a long time. SUMMARY OF THE INVENTION An object of the present invention is to provide a light guide plate having a high light transmittance, and 3 201028744 can uniformly diffuse light emitted from a light source. In order to achieve the foregoing objective, the light guide plate provided by the present invention comprises a substrate and a plurality of reflective particles, the substrate is made of a thermoplastic plastic, and the reflective particles are dispersed in the substrate, and the average particle diameter thereof is Each of the reflective particles has a core and a shell layer, and the shell layer is composed of Α12〇3, Β2〇3, BaC03, Bi2〇3, CaC03, Ce02,
Cr203、CoO、Co304、CuO、Dy2〇3、Er203、Eu203、Fe203、 Ga203、Ge203、Gd203、Hf02、Ho203、：ln2〇3、k203、La203、 Li2C03、MgO、MgC03、Mn203、Mn304、Mo03、Nb205、 Nd203、NiO、PbO、Pb304、PqOh、Sb203、Si02、Sm203、 Sn02、SrC03、Ta205、Tb407、Te02、W03、V205、Y203、Cr203, CoO, Co304, CuO, Dy2〇3, Er203, Eu203, Fe203, Ga203, Ge203, Gd203, Hf02, Ho203, :ln2〇3, k203, La203, Li2C03, MgO, MgC03, Mn203, Mn304, Mo03, Nb205 , Nd203, NiO, PbO, Pb304, PqOh, Sb203, SiO2, Sm203, Sn02, SrC03, Ta205, Tb407, Te02, W03, V205, Y203,
Yb2〇3、ZnO 或 Zr02 所製成。 【實施方式】 為了更暸解本發明之特點所在，茲舉以下一較佳實施 例並配合圖式說明如下，其中： 第一圖係本發明一較佳實施例之示意圖。 請參閱第一圖，本發明一較佳實施例所提供之導光板 10係包含有一基材12與多數反射微粒14。 該基材12係由熱塑性塑膠所製成，例如甲基丙烯酸樹 脂(methyl methacrylate resin)、聚氯乙烯(polyvinyl chloride) 或聚苯乙烯(polystyrene)’其中，該甲基丙烯酸樹脂係包含 有聚甲基丙稀酸甲醋(polymethyl methacrylate)、聚曱基丙 烯酸乙酯、聚曱基丙烯酸丙酯、聚甲基丙烯酸丁酯或聚甲 4 201028744 基丙稀酸戊g旨。 該等反射微粒14係呈球形且均勻地散佈於該基材12 中，依據HORIBA LB-500高濃度超微粒徑分佈分析儀 (dynamic light scattering submicron particle size distribution analyzer)之分析結果，該等反射微粒14之平均粒徑約 3μιη〜5μπι，該等反射微粒14分別具有一核心16與一殼層 18，該核心16係由Si〇2所製成，該殼層18則由八12〇3所 製成’该殼層之平均厚度約ΐ.5μηι〜2.5μιη，該等反射微粒 ® 之重量約為該導光板10重量之1 %。 實際製造時，係先將研磨完成之反射微粒14均勻分散 至曱基丙烯酸甲酯寡聚物中，再利用澆注方式成型，同時 在適當之溫度下令曱基丙烯酸曱酯進一步聚合形成聚甲基 丙烯酸曱酯(ΡΜΜΑ)’即可形成内部具有多數反射微粒14 之導光板10。 由於本發明之導光板10内部具有多數反射微粒14， ❹ 當光線由導光板側面或底面進入時，光線被該等反射微粒 14朝各方向反射’而於導光板頂面形成一均勻之面光源， 使該導光板兼具擴散光線之功能，若光源20設於導光板 10侧邊，則導光板10底側可設一反射板22，用以避免光 線由導光板10底部漏出’如第一圖所示；再者，且由於該 等反射微粒14之粒徑極小，幾乎不影響該導光板之透光 率’由肉眼完全看不出與純ΡΜΜΑ板之差異。藉此，本發 明之導光板可取代傳統導光板與擴散板之組合，降低傳統 導光板與擴散板間之光損，並提高輝度與均勻度。 5 201028744 基於本發明之精神，導光板之成分、反射微粒之成分 或大小均可加以變化，進一步之實驗顯示：反射微粒之平 均粒徑在Ο.ίμιη〜ΙΟΟμηι均可，以較佳，該殻屏 之平均厚度在0·05μιη〜50μιη亦可，該殼層可由其他金屬氧 化物如 B203、BaC03、Bi203、CaC03、Ce02、Cr2〇3、CoC)、Made of Yb2〇3, ZnO or Zr02. BRIEF DESCRIPTION OF THE DRAWINGS In order to better understand the features of the present invention, the following description of the preferred embodiments and the accompanying drawings. Referring to the first drawing, a light guide plate 10 according to a preferred embodiment of the present invention comprises a substrate 12 and a plurality of reflective particles 14. The substrate 12 is made of a thermoplastic plastic, such as a methyl methacrylate resin, a polyvinyl chloride or a polystyrene, wherein the methacrylic resin contains polymethyl Polymethyl methacrylate, polyethyl methacrylate, propyl methacrylate, polybutyl methacrylate or polymethyl 4 201028744 propyl acrylate. The reflective particles 14 are spherical and uniformly dispersed in the substrate 12, and are reflected according to the analysis results of the HORIBA LB-500 dynamic light scattering submicron particle size distribution analyzer. The particles 14 have an average particle diameter of about 3 μm to 5 μm, and the reflective particles 14 have a core 16 and a shell 18, respectively. The core 16 is made of Si〇2, and the shell 18 is made of eight 12〇3. The average thickness of the shell layer is about 55. 5 η 〜 2.5 μιη, and the weight of the reflective particles о is about 1% by weight of the light guide plate 10. In actual production, the polished reflective particles 14 are uniformly dispersed into the methyl methacrylate oligomer, and then formed by casting, and the decyl acrylate is further polymerized at a suitable temperature to form polymethacrylic acid. The oxime ester (ΡΜΜΑ) can form a light guide plate 10 having a plurality of reflective particles 14 therein. Since the light guide plate 10 of the present invention has a plurality of reflective particles 14 inside, when the light enters from the side or the bottom surface of the light guide plate, the light is reflected by the reflective particles 14 in all directions to form a uniform surface light source on the top surface of the light guide plate. The light guide plate has the function of diffusing light. If the light source 20 is disposed on the side of the light guide plate 10, a reflector 22 may be disposed on the bottom side of the light guide plate 10 to prevent light from leaking from the bottom of the light guide plate 10. As shown in the figure; and because the particle size of the reflective particles 14 is extremely small, the transmittance of the light guide plate is hardly affected by the naked eye. Therefore, the light guide plate of the present invention can replace the combination of the conventional light guide plate and the diffusion plate, reduce the light loss between the conventional light guide plate and the diffusion plate, and improve the brightness and uniformity. 5 201028744 According to the spirit of the present invention, the composition of the light guide plate and the composition or size of the reflective particles can be changed. Further experiments show that the average particle diameter of the reflective particles is Ο. ίμιη~ΙΟΟμηι, preferably, the shell The average thickness of the screen may be from 0.05 μm to 50 μm, and the shell layer may be made of other metal oxides such as B203, BaC03, Bi203, CaC03, Ce02, Cr2〇3, CoC).
Co304、CuO、Dy203、Er2〇3、Eu203、Fe203、Ga2〇3、Ge2〇3、 Gd203、Hf02、Ho203、In2〇3、K203、La203、Li2C03、MgO、 MgC03、Mn203、Mn3〇4、Mo03、Nb205、Nd203、NiO、Co304, CuO, Dy203, Er2〇3, Eu203, Fe203, Ga2〇3, Ge2〇3, Gd203, Hf02, Ho203, In2〇3, K203, La203, Li2C03, MgO, MgC03, Mn203, Mn3〇4, Mo03, Nb205, Nd203, NiO,
PbO、Pb304、PgOh、Sb203、Si02、Sm203、Sn02、SrC03、 Ta205、Tb407、Te02、W03、V205、Y203、Yb203、ZnO 或Zr02所製成。該核心則可由Si02、Ti02或與該殼層相 同材質所製成，該等反射微粒之重量可為該導光板重量之 0.1〜20%。舉凡此等易於思及之變化，均應為本發明申請 專利範圍所涵蓋。 ❹ 6 201028744 【圖式簡單說明】 第一圖係本發明一較佳實施例之示意圖。 【主要元件符號說明】 10導光板 12基材 14反射微粒 16核心 18殼層 20光源 22反射板PbO, Pb304, PgOh, Sb203, SiO2, Sm203, Sn02, SrC03, Ta205, Tb407, Te02, W03, V205, Y203, Yb203, ZnO or Zr02. The core may be made of SiO 2 , TiO 2 or the same material as the shell layer, and the weight of the reflective particles may be 0.1 to 20% by weight of the light guide plate. Any changes that are easy to think of should be covered by the scope of the patent application. ❹ 6 201028744 BRIEF DESCRIPTION OF THE DRAWINGS The first drawing is a schematic view of a preferred embodiment of the present invention. [Main component symbol description] 10 light guide plate 12 base material 14 reflective particles 16 core 18 shell layer 20 light source 22 reflector
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