1314627 九、發明說明： 【發明所屬之技術領域】 本發明係關於適用於在個人電腦及文字處理機等辦公室 自動化機器、顯示影像信號之各種監視器，例如面板監視 器、電視監視器等中所採用之顯示裝置，室内外空間之面 光源裝置中使用之顯示裝置及看板等之導光板及其製造方 法〇 【先前技術】 、透明熱可塑性樹脂，其中尤其甲基丙烯酸酯系樹脂，雖 一由於優良之透光性及機械特性至今被用在很多照明用 途，尤其近年來，被使用作爲具備照明用燈之顯示裝置等 之#光用導光板。作爲該背光之方式，通常採用將導光板 挾持於光源與液晶單元之間之所謂直下式、與將光源安裝 於導光板之邊緣之所謂邊緣光源方式2種，現在邊緣光源 方式爲主流。尤其，近年，顯示裝置之高亮度化、大型 化、薄型化之要求強烈，基於，，更明亮、更大、更薄"之商 理念開發仍在繼續，尤其強烈期望開發於邊緣光源方式 中以可冗度且具有精致的晝面之面發光裝置。 爲此，即使於光源裝置中使用之導光板，非常強烈地要 长使由在側面配設之光源燈入射之光的入射光有效率且均 一地向射出面射出之導光板。 關於藉由導光板之高亮度化之方法，至今，已揭示有數 種f術例如，揭示有藉由於導光板之中將光擴散粒子分 散此入而传到均_發光面之方法（例如，參照專利文獻1)， 106098.doc 1314627 又，揭禾有藉由採用使在違_本4 史隹導先板中包含有折射率不同之微 粒子之光散射性塑膠材料、將導光板高亮度化之方法（例 如，參照專敎獻2)n該等方絲序繁雜。 [專利文獻1 ]曰本專利特公昭39_丨丨94號公報 [專利文獻2]曰本專利特開平4_145485號公報 >若在導光板中存在異物等則由光源燈入射之光散射，使 亮度降低。又’大亮點在液晶監視器等之晝面上爲瑕麻 點。導光板之高亮度化，雖意圖藉由調配與光擴散劑粒子 及導光板折射率不同之, U之粒子之方法，惟仍未達成減小亮 點、精緻化之意圖。 【發明内容】 。本發明之目的係提供㈣於在顯示影像信號之各種監視 器’例如面板監視器、電視監視器等中所採用之顯示裝 置’在室内外空間之照明裝置中使用之顯示裝置及看板等 中之導光板及其製造方法。 本發明者們爲了解決上述課題銳意研究之結果，發現藉 由減少導光板中之亮點’可得高亮度之導光板，而完成本 發明。 即，本發明係 U] 一種背光用導光板，其包含透明熱可塑性樹脂基 板該基板係面爲光射出面、且319x150 mm的面積上 之0.1 mm2以上之尺寸的亮點的數目未達2〇點者。 [2]如上述[η之導光板’其中上述透明熱可塑性樹脂基 板係選自由甲基丙晞酸自旨系樹脂、聚碳酸醋樹脂及環狀稀 106098.doc 1314627 異戊二烯等共軛二烯所成之二烯系軟質聚合體、由原冰片 烯、環戊烯等環狀烯烴所成之環狀烯烴系軟質聚合體、由 有機聚矽氧烷系軟質聚合體、α,β-不飽和酸與其衍生物所 成之軟質聚合體、不飽和醇及胺或其醯基衍生物或縮醛所 成之軟質聚合體、環氧化合物之聚合體、氟系橡膠等。 苯乙烯系樹脂係以苯乙烯作爲必須成分之均聚物、共聚 物及由該等之聚合物與其他樹脂製得之混合物等。尤其， 以聚苯乙烯、為丙烯腈與苯乙烯之共聚合體樹脂之八8樹 月曰、為曱基丙烯酸酯與苯乙烯之共聚合體之MS樹脂爲 佳。再者’在苯乙烯系樹脂相中分布有橡膠之透明強化聚 苯乙烯亦可良好地使用。苯乙烯系樹脂之製造方法，並未 特別限定’可使用週知慣用之方法。 所謂非晶性聚酯係在由乙二醇、丙二醇、丨，4_丁二醇、 新戊一醇及己二醇等脂肪族二醇、環己烧二甲醇等脂環族 二醇 '雙苯酚、1，3-雙（2-羥基乙氧基）苯及丨，4•雙（羥基乙 氧基）苯等芳香族二羥基化合物、及選自由該等之2種以上 所成之群之二羥基化合物單體、與對苯二甲酸、間苯二甲 ^ 一甲酸酸專方香族二叛酸、草酸、己二酸、癸 二酸、琥珀酸及十一碳二酸等脂肪族二羧酸、六氫對苯二 甲酸等脂環族二羧酸、及選自由該等之2種以上所成之群 之二羧酸單體形成之聚酯中之非晶性樹脂。非晶性聚酯之 製造方法，並未特別限定，可使用週知慣用之方法。至於 作爲非晶性聚®旨可容易地獲得之市售品牌，有爲Eastman K〇dak公司之產品之KODARPETG或PCTA等。 106098.doc 1314627 製）。藉由直流電壓穩定裝置施加12 V之電壓於冷陰極 管，20分鐘點燈後，藉由於離發光面1 m之位置設置之亮 度計（CA-1000 :美能達製），測定將發光面全體分割成縱 向19χ橫向19=361之測定點的各自的亮度。隨後由所得361 點之測定值算出平均亮度。 圖1及2中’ Α表示光源（冷陰極管）、β表示燈罩、C表示 透明熱可塑性樹脂基板（導光板）、D表示光反射薄板、及e 表示光擴散薄板。 (甲基丙烯酸酯系樹脂聚合體-A之製造） 將甲基丙烯酸甲酯95 ·0重量份、丙稀酸曱酯5.〇重量份、 過氧化十二烧醯0.15重量份、正辛硫醇〇·25重量份、去離 子水130重量份及氫氧化鋁0.65重量份投入於2〇〇公升之聚 合機並攪拌混合。於反應溫度8(TC懸浮聚合15〇分鐘、繼 而於10 0 °C熟成6 0分鐘使聚合反應實質上終止。隨後，將 聚合反應液冷卻至5(TC，投入稀硫酸、清洗脫水乾燥處 理、製得熔融流率（ISO-1139-Condl3)為1·〇 g/10分鐘之甲 基丙烯酸酯系樹脂聚合體-A。採用電磁振動式篩分測定器 (三田村理研工業股份有限公司製電磁振動式AS2〇〇 DISIT)，將§式料1〇〇 g置於由公稱尺寸5 00-42 5 _3 5 5-3 00. 25〇-15〇-15〇以下之7段而成之篩之最上段篩上，以搖筛機 振動10分鐘後，稱量各篩上之甲基丙烯酸酯系樹脂聚合 體，繪出累積殘留分布曲線，求出中值直徑，平均粒徑爲 0_39 mm。 (甲基丙烯酸酯系樹脂聚合體-B之製造） 106098.doc • 16- 1314627 於由曱基丙烯酸甲酯79.9重量％、丙烯酸甲酯5.丨重量 %、及乙基苯15重量％所成之單體混合物中，添加丨，丨_雙 (第三丁基過氧基）-3,3,5-三曱基環己烷150 ppm及正辛硫醇 300 ppm’以完全混合型聚合反應機於聚合溫度滯留 時間2.0小時使聚合，連續地進行聚合至聚合轉化率5 3 %， 將聚合液連續地由聚合反應機取出，隨後以加熱板加熱至 260°C，通過加熱板之間隙使流延落下。脫揮發罐維持於 30 Torr及230°C，將聚合體與未反應單體及溶劑分離。聚 合體於擠壓機連續地以熔融狀態移送，通過擠壓機由模頭 擠壓成線狀’水冷卻（水溫度60°C之浴槽）並以切線機切 斷，製得熔融流率（130-1139-(：〇11(113)1.0§/1〇分鐘之甲基 丙烯酸酯系樹脂聚合體-B。 [實施例1] 於甲基丙稀酸醋系樹脂聚合體_A中，將調整成篩公稱尺 寸法150以下含量成5%之擠塵原料，以由具有薄板用τ型 模具（模具溫度：250。〇之150 mm<j)單軸擠壓機（機筒溫 度：自進料側 200。〇-210。〇210。(：-26(^-260。(3-240。〇與經 調節溫度之3根拋光輥軸（輥軸溫度：8〇。〇收取裝置而成之 擠壓薄板成形機，在機筒與τ型模具之間，採用SUS3製 200網目篩網，以擠壓量6〇〇 Kg/小時擠壓，製得寬1〇〇〇 mm、厚度6 mm之甲基丙烯酸酯系樹脂擠壓板（擠壓 板-A1)。由製得之擠壓板，採用圓鋸，切成寬15〇 mm '長 220 mm之尺寸，採用如圖示之亮點測定裝置測定亮點 後之結果揭示於表丨。隨後由製得之擠壓板，採用圓鋸， 106098.doc •17· 1314627 切成寬241 mm、長319 mm之尺寸，採用精密研磨機（PLA-BEAUTY : MEGARO TECHNICA股份有限公司製）將切成 之板的切裁面研磨，進而實施拋光精加工成鏡面狀，隨 後，採用經實施15吋尺寸之網點分級之印刷篩網，至於油 墨使用 MAT medium SR931(MINO INTERNATIONAL LTD 製）’於導光板之一面進行網版印刷而製得導光板。將採 用如圖2所示之亮度測定裝置測定亮度之結果揭示於表1。 [比較例1] 除採用將在實施例1中作爲擠壓原料甲基丙烯酸酯系樹 脂聚合體-A之篩公稱尺寸15〇以下含量調整成20%之擠壓 原料以外’與實施例1同樣地成型擠壓薄板，製得擠壓板_ B 1。進行與實施例1同樣之測定，將所得結果揭示於表1。 [實施例2] 除採用將在甲基丙烯酸酯系樹脂聚合體_B中通過公稱尺 寸14網目金屬網之微粉量調整成〇1%之擠壓原料以外，與 實施例1同樣地成型擠壓薄板，製得擠壓板_C 1。進行與實 施例1同樣之測定’將所得結果揭示於表1。 [比較例2] 除採用將於實施例2中作爲擠壓原料之甲基丙烯酸酯系 树月a聚合體-B之通過公稱尺寸14網目金屬網之微粉量調整 成0.8°/。之擠壓原料以外，與實施例丨同樣地成型擠壓薄 板，製得擠壓板-D1。進行與實施例i同樣之測定，將所得 結果揭示於表1。 [實施例3及4] 106098.doc -18 1314627 採用比較例1及2之擠壓原料’除了代替於機筒與τ型模 具之間之SUS304製200網目篩網而採用4〇〇網目筛網以 外’與實施例1同樣地成型擠壓薄板，製得擠壓板_E1、 F1。進行與實施例1同樣之測定，將所得結果揭示於表1。 [實施例5] 採用以聚丙烯包捲匣式過濾器（神奈川機械工業股份有 限公司製P-1 76P-6-400 ’過滤能力5 μιη以上）過滤後之曱基 丙烯酸甲酯單體’於使部分聚合（聚合率2〇%)之甲基丙烯 擊 •甲®曰部分聚合體重量份中，添加琥珀酸二辛酯續酸 鈉鹽0·01重量份及2,2，-偶氮二（2,4-二甲基戊腈）(Κ〇2重量份 並使溶解後脫氣，注入於預先設定成板厚成6 mm之500 mmx500 mm之無機玻璃之鑄型中，將該鑄型於5(rc之溫水 中浸潰5小時’隨後使於U(rc之空氣浴中滯留ι20分鐘， 使聚合終止。由鑄型取出薄板，製得澆鑄板_A1。進行與 實施例1同樣之測定，將所得結果揭示於表1 β [比較例3] ® 除未將甲基丙烯酸甲酯以匣式過濾器過濾以外，與實施 例5同樣地製得澆鑄板_Β 1。進行與實施例1同樣之測定， 將所得結果揭示於表1。 [實施例6〜8及比較例4] 採用具有薄板用τ型模具（模具溫度：25 0。〇之150 mm(t) 單軸擠壓機（機筒溫度：自進給側2〇〇。〇_21〇。〇210。(：-260°C-260°C-240°C)與經調節溫度之3根拋光輥軸（輥軸溫 度：80°C )收取裝置而成之擠壓薄板成形機，將甲基丙烯 106098.doc -19- 1314627 [表2] 表2 擠壓板 再生 亮點 (個） 平均亮度 (cd/m2) 原料名 混合量 (重量份） 實施例6 擠壓板-A2 再生原料-A 20 7 2946 實施例7 擠壓板-B2 同上 50 12 2930 實施例8 擠壓板-C2 同上 80 15 2915 比較例4 擠壓板-D2 同上 150 40 2830 比較例5 擠壓板-E2 再生原料-B 50 60 2790 實施例9 擠壓板-F2 再生原料-C 50 6 2945 比較例6 擠壓板-G2 同上 150 35 2852 比較例7 擠壓板-H2 再生原料-D 50 55 2813 [表3] 表3 擠壓板 再生 免點 (個） 平均亮度 (cd/m2) 原料名 混合量 (重量份） 實施例10 擠壓板-A3 粉碎清洗品-A 20 5 2950 實施例11 擠壓板-B3 同上 50 10 2932 實施例12 擠壓板-C3 同上 80 14 2917 比較例8 擠壓板-D3 同上 150 38 2832 比較例9 擠壓板-E3 粉碎品-B 50 65 2778 實施例13 擠壓板-F3 粉碎清洗品-C 50 5 2952 比較例10 擠壓板-G3 同上 150 32 2858 比較例11 擠壓板-H3 粉碎品-D 50 62 2800 106098.doc •24· 1314627 [產業上之利用可能性] 本發明之等光板，可適宜地利用於個人電腦及文字處理 π 機等辦公室自動化機器、顯示影像信號之各種監視器，例 ^ 如於面板監視器、電視監視器等中採用之顯示裝置，室内 外空間之照明裝置中使用之顯示裝置及看板等中。 【圖式簡單說明】 圖1係揭示於本發明中之透明熱可塑性樹脂基板之亮點 評價方法之一例者。 〜 _ 圖2係揭示採用本發明之導光板之邊緣光源方式液 源裝置中之亮度評價方法之—例者。 a曰" 【主要元件符號說明】[Technical Field] The present invention relates to various types of monitors, such as panel monitors, television monitors, and the like, which are suitable for use in office automation machines such as personal computers and word processors, and display image signals. Display device used, display device used in indoor and outdoor space surface light source device, light guide plate for kanban and the like, and manufacturing method thereof [Prior Art], transparent thermoplastic resin, especially methacrylate resin, although Excellent light transmission properties and mechanical properties have been used in many lighting applications, and in recent years, it has been used as a light guide plate for light having a display device for lighting lamps. As the method of the backlight, two types of so-called direct light type in which a light guide plate is held between a light source and a liquid crystal cell and a so-called edge light source in which a light source is mounted on an edge of a light guide plate are generally used. In particular, in recent years, the demand for high brightness, large size, and thinness of display devices has been strong, and the development of business concepts based on, brighter, larger, and thinner continues, especially in the development of edge light sources. A surface-emitting device that is versatile and has a delicate face. For this reason, even in the light guide plate used in the light source device, it is very strong to lengthen the light guide plate in which the incident light of the light incident from the light source lamp disposed on the side surface is efficiently and uniformly emitted toward the exit surface. With regard to the method of increasing the brightness of the light guide plate, various methods have been disclosed so far, for example, to disclose a method of transmitting the light-diffusing particles into the uniform light-emitting surface by the light guide plate (for example, reference) Patent Document 1), 106098.doc 1314627 Further, the use of a light-scattering plastic material containing a fine particle having a different refractive index in a precursor plate is used to increase the brightness of the light guide plate. Methods (for example, refer to the special 2) n These lines are complicated. [Patent Document 1] Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. 4-145485. If light is present in the light guide plate, light incident from the light source lamp is scattered. The brightness is reduced. Also, the big highlight is the ramie point on the surface of the LCD monitor. Although the brightness of the light guide plate is increased, it is intended to reduce the brightness and refinement by the method of blending the particles of U with the refractive index of the light diffusing agent particles and the light guide plate. SUMMARY OF THE INVENTION The object of the present invention is to provide (d) a display device used in various monitors for displaying video signals, such as panel monitors, television monitors, etc., in display devices used in lighting devices for indoor and outdoor spaces, kanbans, and the like. Light guide plate and method of manufacturing the same. In order to solve the above problems, the inventors of the present invention have found that a light guide plate having a high luminance can be obtained by reducing the bright spots in the light guide plate, and the present invention has been completed. That is, the present invention is a light guide plate for a backlight comprising a transparent thermoplastic resin substrate, the substrate surface being a light exit surface, and the number of bright spots having a size of 0.1 mm 2 or more on an area of 319 x 150 mm is less than 2 points. By. [2] The above [η light guide plate] wherein the transparent thermoplastic resin substrate is selected from the group consisting of methacrylic acid from a resin, a polycarbonate resin, and a cyclic dilute 106098.doc 1314627 isoprene or the like. a diene-based soft polymer formed of a diene, a cyclic olefin soft polymer formed of a cyclic olefin such as norbornene or cyclopentene, or a soft polyorganosiloxane-based soft polymer, α, β- A soft polymer formed of an unsaturated acid and a derivative thereof, a soft polymer formed from an unsaturated alcohol and an amine or a mercapto derivative or an acetal, a polymer of an epoxy compound, or a fluorine-based rubber. The styrene resin is a homopolymer, a copolymer, and a mixture of the polymer and other resins, which are styrene as an essential component. In particular, it is preferred that the polystyrene, the copolymer resin of acrylonitrile and styrene, and the copolymer of methacrylate and styrene are MS resins. Further, the transparent reinforced styrene in which rubber is distributed in the styrene resin phase can be preferably used. The method for producing the styrene resin is not particularly limited, and a conventionally known method can be used. The amorphous polyester is an aliphatic diol such as ethylene glycol, propylene glycol, hydrazine, 4-butanediol, neopentyl alcohol or hexanediol, or an alicyclic diol such as cyclohexane or diethanol. An aromatic dihydroxy compound such as phenol, 1,3-bis(2-hydroxyethoxy)benzene and anthracene, 4•bis(hydroxyethoxy)benzene, or a group selected from the group consisting of two or more of these Dihydroxy compound monomer, with terephthalic acid, isophthalic acid, monocarboxylic acid, aromatic bismuth, oxalic acid, adipic acid, azelaic acid, succinic acid and undecanedioic acid An alicyclic dicarboxylic acid such as a carboxylic acid or a hexahydroterephthalic acid, or an amorphous resin selected from the group consisting of polyesters of a dicarboxylic acid monomer of a group of two or more of them. The method for producing the amorphous polyester is not particularly limited, and a conventionally known method can be used. As a commercially available brand which is easily available as an amorphous poly®, there are KODARPETG or PCTA which are products of Eastman K〇dak Co., Ltd. 106098.doc 1314627)). A voltage of 12 V was applied to the cold cathode tube by a DC voltage stabilizing device, and after the light was turned on for 20 minutes, the entire light-emitting surface was measured by a luminance meter (CA-1000: manufactured by Minolta) which was placed at a position of 1 m from the light-emitting surface. The respective brightnesses of the measurement points divided into the longitudinal direction 19 and the lateral direction 19=361 are divided. The average brightness was then calculated from the measured value of 361 points obtained. In Figs. 1 and 2, Α denotes a light source (cold cathode tube), β denotes a lamp cover, C denotes a transparent thermoplastic resin substrate (light guide plate), D denotes a light-reflecting sheet, and e denotes a light-diffusing sheet. (Production of methacrylate-based resin polymer-A) 95 parts by weight of methyl methacrylate, 5% by weight of isopropyl acrylate, 0.15 parts by weight of decyl peroxide, and n-octyl sulfide 25 parts by weight of alcohol oxime, 130 parts by weight of deionized water, and 0.65 parts by weight of aluminum hydroxide were placed in a 2 liter liter polymerization machine and stirred and mixed. The polymerization reaction was substantially terminated at a reaction temperature of 8 (TC suspension polymerization for 15 minutes, followed by aging at 100 ° C for 60 minutes. Subsequently, the polymerization reaction solution was cooled to 5 (TC, charged with dilute sulfuric acid, washed and dried, and dried, A methacrylate-based resin polymer-A having a melt flow rate (ISO-1139-Condl3) of 1·〇g/10 minutes was produced. An electromagnetic vibration type sieve measuring device (electromagnetic vibration by Mitamura Riken Industrial Co., Ltd.) was used. AS2〇〇DISIT), the § formula 1〇〇g is placed in the 7th section of the 7th section of the nominal size 5 00-42 5 _3 5 5-3 00. 25〇-15〇-15〇 On the upper sieve, after shaking for 10 minutes with a sieve shaker, the methacrylate resin mixture on each sieve was weighed, and the cumulative residue distribution curve was drawn to obtain a median diameter with an average particle diameter of 0-39 mm. Manufacture of acrylate-based resin polymer-B) 106098.doc • 16- 1314627 A single sheet made of methyl methacrylate 79.9 wt%, methyl acrylate 5. wt%, and ethyl benzene 15 wt% In the mixture, 丨,丨_bis(t-butylperoxy)-3,3,5-trimethylcyclohexane 150 ppm N-octyl mercaptan 300 ppm' was polymerized in a complete mixing type polymerization machine at a polymerization temperature retention time of 2.0 hours, continuously polymerized to a polymerization conversion ratio of 53%, and the polymerization liquid was continuously taken out from the polymerization reactor, followed by heating. The plate was heated to 260 ° C, and the casting was dropped by the gap between the heating plates. The devolatilization tank was maintained at 30 Torr and 230 ° C to separate the polymer from the unreacted monomer and solvent. The polymer was continuously used in the extruder. The molten state is transferred, extruded by a die into a linear 'water cooling (water temperature 60 ° C bath) by an extruder and cut by a tangential machine to obtain a melt flow rate (130-1139-(:〇11( 113) 1.0 § / 1 minute methacrylate-based resin polymer-B. [Example 1] In the methyl acrylate vinegar-based resin polymer _A, it is adjusted to a sieve nominal size method of 150 or less. 5% of the dust-removing material is used to make a single-axis extruder with a thin plate with a τ-type mold (mold temperature: 250 〇 150 mm < j) (barrel temperature: from the feed side 200. 〇-210. 〇 210. (: -26 (^-260. (3-240. 3 with adjusted temperature of 3 polishing roller shafts (roller shaft temperature: 8 The squeezing sheet forming machine made of the 〇-receiving device is extruded between the barrel and the τ-type mold using a SUS3 200 mesh screen and extruded at a pressure of 6 〇〇Kg/hr to obtain a width of 1 〇〇.甲基mm, thickness 6 mm methacrylate resin extrusion plate (extruded plate-A1). The extruded plate is made of a circular saw and cut into a width of 15 mm mm and a length of 220 mm. The results of the bright spot measurement device after measuring the bright spots are disclosed in Table 丨. Subsequently, the obtained extruded plate was cut into a width of 241 mm and a length of 319 mm using a circular saw, 106098.doc •17· 1314627, and cut by a precision grinding machine (PLA-BEAUTY: MEGARO TECHNICA Co., Ltd.) The cut surface of the board was ground and then polished to a mirror-like shape. Subsequently, a printing screen having a 15 吋 size dot grading was used, and the ink was used in a MAT medium SR931 (manufactured by MINO INTERNATIONAL LTD). One side of the screen is screen printed to produce a light guide plate. The results of measuring the brightness using the brightness measuring device shown in Fig. 2 are disclosed in Table 1. [Comparative Example 1] The same procedure as in Example 1 was carried out except that the content of the sieve having the nominal size of the methacrylate-based resin polymer-A of the first embodiment was adjusted to 20% or less. The extruded sheet was formed to obtain a pressed plate _ B 1 . The same measurement as in Example 1 was carried out, and the results obtained are shown in Table 1. [Example 2] Extrusion molding was carried out in the same manner as in Example 1 except that the amount of the fine powder of the mesh metal mesh of the nominal size of 14 was adjusted to 〇1% in the methacrylate-based resin polymer_B. Thin plate, made of extruded plate _C 1. The same measurement as in Example 1 was carried out. The results obtained are shown in Table 1. [Comparative Example 2] The amount of fine powder passing through the nominal size 14 mesh metal mesh was adjusted to 0.8 °/ except that the methacrylate-based a polymer-B which will be used as the extrusion raw material in Example 2 was used. An extruded sheet was molded in the same manner as in Example 以外 except the extruded material, to obtain a pressed sheet-D1. The same measurement as in Example i was carried out, and the results obtained are shown in Table 1. [Examples 3 and 4] 106098.doc -18 1314627 The extrusion raw materials of Comparative Examples 1 and 2 were used instead of the SUS304 200 mesh screen between the barrel and the τ-type mold, and a 4-inch mesh screen was used. The extruded sheets were molded in the same manner as in Example 1 to obtain extruded sheets _E1 and F1. The same measurement as in Example 1 was carried out, and the results obtained are shown in Table 1. [Example 5] A methyl methacrylate monomer filtered by a polypropylene-coated sputum filter (P-1 76P-6-400 'filtering capacity 5 μιη or more) manufactured by Kanagawa Machinery Co., Ltd.) was used. Adding partially polymerized (polymerization rate: 2% by weight) to the part by weight of the methyl acrylate/methyl hydrazine partial polymer, adding 0.2 parts by weight of dioctyl succinate sodium salt and 2,2,-azo two (2,4-dimethylvaleronitrile) (2 parts by weight of ruthenium and degassed after dissolution, and injected into a mold of 500 mm x 500 mm of inorganic glass previously set to a thickness of 6 mm, the mold It was immersed in 5 (r warm water for 5 hours) and then allowed to stand in U (rc air bath for 10 minutes to terminate the polymerization. The thin plate was taken out from the mold to obtain a cast plate _A1. The same procedure as in Example 1 was carried out. The measurement results are shown in Table 1 β [Comparative Example 3] ® A cast plate _Β 1 was obtained in the same manner as in Example 5 except that methyl methacrylate was not filtered through a 匣 filter. 1 In the same measurement, the results obtained are shown in Table 1. [Examples 6 to 8 and Comparative Example 4] A mold having a τ type having a thin plate was used. Temperature: 25 0. 150 mm (t) single-axis extruder (barrel temperature: 2〇〇 from the feed side. 〇_21〇. 〇210. (:-260°C-260°C-240 °C) Extrusion sheet forming machine with three polishing roller shafts (roller shaft temperature: 80 °C) with adjusted temperature, methacrylic 106098.doc -19- 1314627 [Table 2] Table 2 Extrusion plate regeneration highlights (units) Average brightness (cd/m2) Raw material name mixing amount (parts by weight) Example 6 Extrusion plate - A2 Recycled raw material - A 20 7 2946 Example 7 Extrusion plate - B2 Same as above 50 12 2930 Example 8 Extruded plate - C2 Same as above 80 15 2915 Comparative Example 4 Extruded plate - D2 Same as above 150 40 2830 Comparative Example 5 Extruded plate - E2 Recycled raw material - B 50 60 2790 Example 9 Extruded plate - F2 Recycled raw material - C 50 6 2945 Comparative Example 6 Extruded plate - G2 Same as above 150 35 2852 Comparative Example 7 Extruded plate - H2 Recycled raw material - D 50 55 2813 [Table 3] Table 3 Renewal of extruded plate (point) Average brightness (cd /m2) Raw material name mixing amount (parts by weight) Example 10 Extrusion plate - A3 Crushing cleaning product - A 20 5 2950 Example 11 Extrusion plate - B3 Same as above 50 10 2932 Example 12 Extrusion plate - C3 Same as above 80 14 2917 Comparative Example 8 Extrusion plate - D3 Same as above 150 38 2832 Comparative Example 9 Extrusion plate - E3 Pulverized product - B 50 65 2778 Example 13 Extrusion plate - F3 Crushing cleaning product - C 50 5 2952 Comparative Example 10 Extrusion plate - G3 Ibid. 150 32 2858 Comparative Example 11 Extruded plate - H3 pulverized product - D 50 62 2800 106098.doc • 24· 1314627 [Industrial use possibility] The optical plate of the present invention can be suitably used for personal computers and characters Office automation equipment such as a π machine, and various monitors for displaying video signals, such as display devices used in panel monitors, television monitors, etc., display devices and kanbans used in lighting devices for indoor and outdoor spaces. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing an example of a method for evaluating a bright spot of a transparent thermoplastic resin substrate in the present invention. ~ _ Fig. 2 is a view showing a method of evaluating the brightness in the liquid source device using the edge light source of the light guide plate of the present invention. a曰" [Main component symbol description]
A B C D E 光源（冷陰極管） 燈罩 透明熱可塑性樹脂基板(導光板） 光反射薄板 光擴散薄板A B C D E light source (cold cathode tube) lampshade transparent thermoplastic resin substrate (light guide plate) light reflective sheet light diffusing sheet
106098.doc •25-106098.doc •25-