201033644 六、發明說明： 【發明所屬之技術領域】 本發明有關能明亮地且以更自然的色調（hue )照射 例如透射型影像顯示面板（transmitted image display panel)等之光擴散板（light diffusion plate)。 【先前技術】 液晶顯示裝置而言，周知有於例如具備有液晶片之液 晶面板（影像顯示部）的背面側作爲backlight (背光板） 而配置有面光源裝置（plane light source device)之構成 者。前述backlight用的面光源裝置而言，周知有於燈匣 (light box)(筐體）內配置有複數個光源之同時於光源 的前面側配置有光擴散板之構成的面光源裝置（參考曰本 專利特開2004- 1 7093 7號公報（專利文獻1 ))。 上述光擴散板而言，由於即使畫面尺寸增大仍然能製 得比較輕量者之故，在廣泛採用使光擴散粒子分散於透明 樹脂中所成者。 【發明內容】 然而，此種周知之光擴散板，往往係照射透射型影像 顯示面板等的明亮度不足、或所得照明並非爲自然的色調 者之情形，於此情形，則採用該光擴散板所構成之液晶顯 示裝置等的透射型影像顯示裝置中，有發生顯示影像之明 亮度不足，或難於獲得自然的色調之顯示影像之問題。 -5- 201033644 本發明，係鑑於如此技術背景所開發者，以提供一種 能更明亮地照明透射型影像顯示面板等之光擴散板爲目的 。又，本發明，亦以提供一種能更明亮地且以更自然的色 調照明透射型影像顯示面板等之光擴散板爲目的。 本發明人等，爲達成前述目的而專心硏究之結果發現 ，波長600nm的光的光線透射率係對照明的明亮度有影響 者，再發現於樹脂的製造過程中所添加之鋅化合物等係對 照明的色調有影響者之事實，而終於完成本發明。亦即，© 本發明提供下列手段。 [1] 一種光擴散板，其係由透明樹脂及光擴散粒子（ light diffusion particle)所成，其特徵爲：當波長 600nm 的光透射200mm的光程長（light pass length)時的光線 透射率（light transmissivity)爲 65 %以上。 [2] 如前項[1]所記載之光擴散板，其中前述透明樹脂 係含有鋅化合物之組成物，而該組成物中的鋅的含有率爲 1 50ppm 以下。 @ [3] 如前項[2]所記載之光擴散板，其中前述鋅化合物 係硬脂酸鋅。 [4] 如前項[1]至[3]之任一項所記載之光擴散板，其中 前述透明樹脂含有聚苯乙烯。 [5] 如前述[1]至[4]之任一項所記載之光擴散板，其中 前述光擴散粒子，係選自丙烯基系聚合物粒子及矽氧烷系 聚合物粒子所成群之1種以上的聚合物粒子。 [6] 如前述[1]至[5]之任一項所記載之光擴散板，其中 -6- 201033644 前述光擴散粒子的平均粒徑爲0.5至5μιη，前述透明樹脂 的折射率與前述光擴散粒子的折射率之差的絕對値爲〇.〇5 以上，而前述透明樹脂每1〇〇質量份之前述光擴散粒子的 含量爲0.1至10質量份。 [7] —種面光源裝置，其特徵爲：具備有前述[1]至[6] 之任一項所記載之光擴散板，及經配置於該光擴散板的背 面側之複數個光源》 ® [8]—種透射型影像顯示裝置，其特徵爲：具備有前述 [1]至[6]之任一項所記載之光擴散板，及經配置於該光擴 散板的背面側之複數個光源，以及經配置於前述光擴散板 的前面側之透射型影像顯示面板。 於[1]的發明中，光擴散板係由透明樹脂及光擴散粒子 所成，而前述透明樹脂，係由於當波長600nm的光透射 2 00mm的光程長時的光線透射率爲6 5 %以上之故，可成爲 能更明亮地照明透射型影像顯示面板等者。 ® 於[2]的發明中，雖然前述透明樹脂係含有鋅化合物之 組成物者，惟由於該組成物中之鋅的含有率係被設定爲 150PPm以下之故，能以更自然的色調照明透射型影像顯 示面板等。在此，「ppm」係表示質量百萬分率之單位。 於[3]的發明中，由於前述鋅化合物係硬脂酸鋅之故， 在因硬脂酸鋅潤滑劑所產生之潤滑性作用而提升成型加工 時的成型性之下，成爲能以更自然的色調進行照明者。 於[4]的發明中，由於前述透明樹脂係含有聚苯乙烯之 構成之故，透明性高且能以更自然的色調進行照明。 201033644 於[5]的發明中，由於作爲前述光擴散粒子而採用有選 自丙烯基系聚合物粒子及矽氧烷系聚合物粒子所成群之1 種以上的聚合物粒子之故，能以更明亮地且自然的色調進 行照明。 於[6]的發明中，由於前述光擴散粒子的平均粒徑爲 0.5至5μιη，前述透明樹脂之折射率與前述光擴散粒子的 折射率之差的絕對値爲〇.〇5以上，而前述透明樹脂每100 質量份的前述光擴散粒子的含量爲0.1至10質量份之故 ® ，有能使光擴散粒子充分均勻分散之同時，以較少量的光 擴散粒子使用量即可充分擴散光之優點。 於[7]的發明中，可提供能進行更明亮的照明之面光源 裝置。又，如光擴散板具備有[2]之構成時，則可提供能進 行更明亮且更自然的色調的照明之面光源裝置。 於[8]的發明中，可提供能獲得更明亮的顯示影像之透 射型影像顯示裝置。又，如光擴散板具備有[2]的構成時， 則可提供能獲得更明亮且更自然的色調的顯示影像之透射 ® 型影像顯示裝置。 [發明之最佳實施形態] 將有關本發明之透射型影像顯示裝置（30)之一實施 形態之液晶顯示裝置，表示於第1圖中。第1圖中，（30 )爲液晶顯示裝置，（1 1 )爲液晶片（light crystal cell ) ' (12) (13)爲偏光板（polarizing plate) ， （1)爲 面光源裝置（backlight )。於前述液晶片（1 1 )的上下兩 -8 - 201033644 側，分別配置有偏光板（12) (13) ’並使用此等構成構 件（11) (12) (13)而構成有作爲透射型影像顯示部之 液晶面板（20)。 再者，前述液晶片（1 1 )，係由於一對透明電極間內 封有液晶化合物所成。前述液晶面板（20 )而言’具備有 彩色濾光器（color filter)等而能顯示彩色影像者很適合 使用。又，前述液晶面板（20) ’亦可爲具備有爲調整從 鲁斜方向觀看時的對比（contrast )、色調等之用的相位差 板（phase difference plate)之構成。 前述面光源裝置（1 )，係經配置於前述液晶面板（ 20 )下側的偏光板（13 )的下面側（背面側）者。亦即’ 此種液晶顯示裝置（30)，係直下型（direct type)液晶 顯示（display)裝置。 前述面光源裝置（1)，具備有：平面觀看時爲矩形 狀而上面側（前面側）爲無蓋的薄箱型形狀的燈匣（5 ) ，及於該燈匣（5)內按互相離間之方式所配置之複數個 線狀光源（2)，以及經配置於此等複數個線狀光源（2) 的上方側（前面側）之光擴散板（3)。前述光擴散板（3 )，係對前述燈匣（5)按能遮塞其無蓋面之方式載置並 加以固定者。又，於前述燈匣（5)內面，設置有光反射 層（未圖示）。 前述光源（2 )而言，並不特別加以限定，惟例如除 冷陰極管（CCFL )、外部電極螢光管（EEFL )、平面螢 光燈（FFL )等的線狀光線之外，尙可採用發光二極體（ 201033644 LED)等的點狀光源。 前述光擴散板（3)，係由透明樹脂及光擴散板所成 ，而於透明樹脂中分散有光擴散粒子。本發明中，作爲前 述透明樹脂而採用波長600nm的光透射200mm的光程長 時的光線透射率爲65%以上之透明樹脂。 因而，如使用前述面光源裝置（1)，則能更明亮地 照明液晶面板（20 )。因此，如採用前述液晶顯示裝置（ 30)，則可發揮能獲得更明亮的顯示影像之效果。 © 又，本實施形態中，前述透明樹脂係含有鋅化合物之 組成物，而該組成物中的鋅（Zn原子）的含有率爲經設 定於1 50ppm以下。 因而，如使用前述面光源裝置（1)，則能以更自然 的色調照明液晶面板（20 )。因此，如採用前述液晶顯示 裝置（30)，則可發揮能獲得更自然的色調的顯示影像之 效果。 再者，於前述液晶顯示裝置（30)中，亦可於前述光 ® 擴散板（3 )與前述液晶面板（20 )之間配置其他的光擴 散板。又，亦可於前述光擴散板（3)與前述液晶面板（ 20 )之間配置爲明亮地照明前面側之用的光學構件。前述 光學構件而言，可例舉：美國3M社製「DBEF」（商品名 )等。 前述透明樹脂而言，無著色者很合適採用。前述透明 樹脂而言，並不特別加以限定，惟可例舉：聚苯乙烯、甲 基丙烯酸甲酯一苯乙烯共聚物、甲基丙烯酸一苯乙烯共聚 -10 - 201033644 物、馬來酸酐一苯乙烯共聚物、聚甲基丙烯酸甲酯、甲基 丙烯酸甲酯一丙烯酸酯共聚物、聚碳酸酯、聚丙烯、聚環 烯烴、環烯烴-α鏈烯烴共聚物等。其中，從吸濕性較低的 觀點來看，聚苯乙烯、聚丙烯、聚環烯烴、以及環烯烴-α 鏈烯烴共聚物很適合採用。 又，前述透明樹脂而言，採用波長600nm的光透射 2 00mm的光程長時的光線透射率爲6 5 %以上之透明樹脂。 ®如此，則可提升因透射光所得之照度（illuminance )。其 中，前述透明樹脂而言，較佳爲採用波長6 OOxim的光透射 200mm的光程長時的光線透射率爲70%以上之透明樹脂。 例如，在液相（liquid phase )中依懸浮聚合法（ suspension polymerization ) 、分散聚合法（dispersion polymerization )等方法而使原料單體進行透明樹脂之製 造時，所得透明樹脂中所殘留之溶劑，或於此溶劑中所添 加之觸媒成分、添加劑等，亦可能會作爲不純物而對波長 ~ 600nm的光的光線透射率有所影響之情形。或者，對因聚 合所得透明樹脂以各種目的少量所添加之添加劑等，亦可 能會作爲不純物而對波長600nm的光的光線透射率有所影 響。因此，本發明中所採用之「波長600nm的光透射 200mm的光程長時的光線透射率爲65%以上的透明樹脂」 ，如選擇例如：在製造過程中所使用之觸媒或添加劑等的 使用量少者、聚合後經充分洗滌者，對因聚合所得之透明 樹脂未添加有添加劑等者，對因聚合所得之透明樹脂所添 加之添加劑量少者等而採用，則可製得。 -11 - 201033644 又，前述透明樹脂而言，可爲含有鋅化合物之組成物 ，惟在此情形時前述組成物中的鋅含有率（係Zn原子的 含有率而非鋅化合物的含有率），較佳爲設定於150ppm 以下。如鋅的含有率爲1 5 Oppm以下時，則由於經抑制一 般認爲對色調有影響之鋅的含有率之故，可以更自然的色 調照射透射型影像顯示面板（20)。其中，前述組成物中 的鋅的含有率，較佳爲設定於90ppm以下，更佳爲設定於 50ppm以下，特佳爲設定於lOppm以下。 ® 前述鋅化合物而言，並不特別加以限定，惟可例舉： 硬脂酸鋅、月桂酸鋅、對第三丁基安息香酸鋅、1,2-羥基 硬脂酸鋅、肉豆蔻酸鋅（Zinc miri state)等。 由於前述硬脂酸鋅之使用而可獲得潤滑性提升效果之 故，因該硬脂酸鋅之含有，而對透明樹脂與成型加工機的 金屬面之間的摩擦之降低、成型加工機對金屬面的樹脂附 著之防止及脫模性之提升有助益。 前述鋅的含有率，係如下述方式所求得之値（就實施 © 例中的鋅的含有率亦爲同樣方式）。亦即，將含有鋅化合 物之組成物採取於白金皿上，添加硫酸後加熱以使有機物 碳化，接著將所得碳化物在電氣爐中在550 °C下使其灰化 ，並對此灰分添加鹼熔融劑以進行加熱融解。接著，使所 得之融解物溶解於硝酸及水中，並調整爲能成爲既定容積 之方式以作爲供試液，將此供試液中的Zn (元素），利 用 ICP-AES ( Thermofisher S cientific 社製的感應式偶合 電漿原子發射光譜分析裝置「iCAP6500」）加以測定。 -12- 201033644 前述光擴散粒子而言’祗要是對前述透明樹脂爲非相 溶性，且顯示與該透明樹脂不相同的折射率，且具有使穿 過光擴散板（3)之穿透光擴散之功能之粒子（包括粉末 )則並不特別加以限定’例如，可爲由無機材料所成之無 機粒子’亦可爲由有機材料所成之有機粒子。此種光擴散 粒子而Η，亦可採用經以偶合劑（coupling agent)等的表 面處理劑實施表面處理者。 構成前述無機粒子之無機材料而言，並不特別加以限 定，惟可例舉：二氧化矽、碳酸鈣、硫酸鋇、氧化鈦、氫 氧化錯、無機玻璃、雲母、滑石、白炭黑（white carbon )、氧化鎂、氧化鋅等。 構成前述有機粒子之有機材料而言，並不特別加以限 定，惟可例舉：丙烧基系聚合物、砍氧院系聚合物、苯乙 烯系聚合物等。 此等之中，從由於不純物少之故可更提升照度之同時 能使光擴散板更輕量化的觀點來看，較佳爲採用有機粒子 ，特別合適者爲丙烯基系聚合物粒子、矽氧烷系聚合物粒 子。 前述丙烯基系聚合物粒子而言，可例舉：以丙烯基系 單官能單體單元作爲主成分之聚合物，亦即含有丙烯基系 單官能單體單元50質量％以上之聚合物的粒子。含有前述 丙烯基系單官能單體單元50質量％以上之聚合物的粒子而 言，可爲單體單元的全部（100質量％ )係丙烯基系單官 能單體單元之聚合物的粒子，亦可爲丙烯基系單官能單體 -13- 201033644 及能與此進行共聚合之單官能單體的共聚物的粒子。 前述丙烯基系單官能單體而言，可例舉：丙烯酸、甲 基丙烯酸、丙烯酸酯、甲基丙烯酸酯等。前述丙烯酸酯而 言，並不特別加以限定，惟可例舉：丙烯酸甲酯、丙烯酸 乙酯、丙烯酸丁酯、丙烯酸環己酯、丙烯酸苯酯、丙烯酸 苄酯、丙烯酸2-乙基己酯、丙烯酸2-羥乙酯等。又，前述 甲基丙烯酸酯而言，並不特別加以限定，惟可例舉：甲基 丙烯酸甲酯、甲基丙烯酸乙酯、甲基丙烯酸丁酯、甲基丙 ® 烯酸環己酯、甲基丙烯酸苯酯、甲基丙烯酸苄酯、甲基丙 烯酸2-乙基己酯、甲基丙烯酸2-羥乙酯等。此等丙烯基系 單官能單體，可以單獨使用，亦可組合2種以上使用。 能與前述丙烯基系單官能單體進行共聚合之單官能單 體’係在分子內具有1個能進行自由基聚合之雙鍵，而能 以該雙鍵與丙烯基系單官能單體進行共聚合之化合物。具 體而言’例如，除苯乙烯之外，尙可舉：氯苯乙烯、溴苯 乙烯等鹵化苯乙烯類、乙烯基甲苯、α-甲基苯乙烯等烷基 © 苯乙烯等的取代苯乙烯等。再者，亦可舉丙烯腈。此等單 官能單體’可以單獨使用，亦可組合2種以上使用。 如前述丙烯基系聚合物粒子爲單體單元的全部（1〇〇 質量％)係丙烯基系單官能單體單元之聚合物的粒子之情 形’以及’丙烯基系單官能單體及能與此進行共聚合之單 官能單體的共聚物的粒子之情形，則其重量平均分子量較 佳爲50萬至500萬。 又’目I』述丙嫌基系聚合物粒子而言，亦可爲丙烯基系 -14- 201033644 單官能單體及能與此進行共聚合之多官能單體的共聚物的 粒子。此種多官能單體，係指分子內具有能與丙烯基系單 官能單體進行共聚合之雙鍵2個以上，且能以此等雙鍵與 丙烯基系單官能單體進行共聚合之化合物之意。此種多官 能單體而言，可例舉：與關於前述苯乙烯系聚合物粒子所 舉示者同樣的多元醇類的甲基丙烯酸酯類'多元醇類的丙 烯酸酯類、芳香族多官能化合物等。此等多官能單體，可 β以單獨使用，亦可組合2種以上使用。 丙稀基系單官能單體及能與此進行共聚合之多官能單 體的共聚物，係交聯結構（bridge structure)的共聚物， 而其凝膠分率（gel fraction)較佳爲10質量％以上者。 又’前述丙烯基系聚合物粒子而言，亦可爲將丙烯基 系單官能單體/能與此進行共聚合之單官能單體/同樣能進 行共聚合之多官能單體加以共聚合所得之三元系共聚物等 的粒子。 § 則述丙烯基系聚合物粒子的折射率，通常爲1.46至 1.55程度’而苯骨架（benzen skeleton)或_原子的含有 率愈大時’有顯示愈大的折射率之傾向。又，此種丙烯基 系聚合物粒子，例如可依懸浮聚合法、微懸浮聚合法（ micro suspension polymerization )、乳化聚合法（ emulsion polymerization )、分散聚合法（dispersion polymerization)等一般性聚合法製造。 前述矽氧烷系聚合物粒子，係可依例如使氯矽烷類加 水分解並縮合之方法所製造之聚合物。前述氯矽烷類而言 -15- 201033644 ’可例舉：二甲基二氯矽烷、二苯基二氯矽烷、苯基甲基 二氯矽烷、甲基三氯矽烷、苯基三氯矽烷等。前述矽氧烷 系聚合物而言，可爲經交聯者。如使其交聯時，則例如， 對矽氧烷系聚合物，使··過氧化苯甲醯、過氧化2,4 -二氯 苯甲醯、過氧化對氯苯甲醯、過氧化二茴香基、過氧化二 第三丁基-2,5-二甲基-2,5-二（第三丁基過氧化）己烷等的 過氧化物進行作用即可。又，如欲作成在末端具有矽烷醇 基之構造之情形，則使其與烷基矽烷類進行縮合交聯（© condensation bridging )。前述經交聯之矽氧烷系聚合物 ’較佳爲對每1個矽原子，結合有有機基2至3個之構造 。此種矽氧烷系聚合物，係亦稱呼爲聚矽氧橡膠、聚矽氧 樹脂之聚合物。矽氧烷系聚合物而言，較佳爲採用在常溫 下爲固體者。 前述砂氧院系聚合物粒子，例如將前述砂氧院系聚合 物加以粉碎即可製得。亦可將具有線狀有機矽氧烷嵌段（ linear organosiloxane block )之硬化性聚合物或其組成物 © 在噴霧狀態下使其硬化，藉以作成粒狀粒子而製得（參考 日本專利特開昭5 9-68 3 3 3號公報）。再者，亦可將烷基 三烷氧矽烷或者其部分加水分解縮合物在氨或胺類的水溶 液中使其加水分解縮合（hydrolysis condensation)，藉以 作成粒狀粒子而製得（參考日本專利特開昭60- 1 3 8 1 3號 公報）。 前述砂氧院系聚合物粒子，較佳爲其重量平均分子量 在50萬至500萬。又，如前述矽氧烷系聚合物爲交聯構 -16- 201033644 造之情形’其凝膠分率較佳爲1 〇質量％以上。前述矽氧烷 系聚合物粒子的折射率，通常爲1·40至1.47程度。 前述苯乙烯系聚合物粒子而言，可例舉：以苯乙烯系 單官能單體單元作爲主成分之聚合物，亦即含有苯乙烯系 單官能單體單元50質量％以上之聚合物的粒子。含有前述 苯乙烯系單官能單體單元50質量％以上之聚合物的粒子而 言’可爲單體單元的全部（100質量％)係苯乙烯系單官 ®能單體單元之聚合物的粒子，亦可爲苯乙烯系單官能單體 及能與此進行共聚合之單官能單體的共聚物的粒子。 前述苯乙烯系單官能單體，係具有苯乙烯骨架，並分 子內具有能進行自由基聚合之雙鍵1個之化合物。具體而 言，例如，除苯乙烯之外，尙可舉：取代苯乙烯。前述取 代苯乙烯而言，可例舉：氯苯乙烯、溴苯乙烯等鹵化苯乙 烯類、乙烯基甲苯、α-甲基苯乙烯等的烷基苯乙烯類等。 能與前述苯乙烯系單官能單體進行共聚合之單官能單 體，係分子內具有能進行自由基聚合之雙鍵1個，且能以 此雙鍵與苯乙烯系單官能單體進行共聚合之化合物。具體 而言，可例舉：甲基丙烯酸甲酯、甲基丙烯酸乙酯、甲基 丙烯酸丁酯、甲基丙烯酸環己酯、甲基丙烯酸苯酯、甲基 丙烯酸苄酯、甲基丙烯酸2-乙基己酯、甲基丙烯酸2-羥乙 酯等甲基丙烯酸酯類，丙烯酸甲酯、丙烯酸乙酯、丙烯酸 丁酯、丙烯酸環己酯、丙烯酸苯酯、丙烯酸苄酯、丙烯酸 2-乙基己酯、丙烯酸2-羥乙酯等丙烯酸酯類，丙烯腈等。 此等單官能單體，可以單獨使用，亦可組合2種以上使用 -17- 201033644 。其中’能與前述苯乙烯系單官能單體進行共聚合之單官 能單體而言’較佳爲採用甲基丙烯酸酯類。 如前述苯乙烯系聚合物粒子爲單體單元的全部（丨00 質量％)係苯乙烯系單官能單體單元之聚合物的粒子之情 形’以及’苯乙烯系單官能單體及能與此進行共聚合之單 官能單體的共聚物的粒子之情形，則其重量平均分子量較 佳爲50萬至500萬。 又’前述苯乙烯系聚合物粒子而言，亦可爲苯乙烯系❹ 單官能單體及能與此進行共聚合之多官能單體的共聚物的 粒子。此等多官能單體，係指分子內具有能進行自由基聚 合之雙鍵2個以上，且能以此雙鍵與苯乙烯系單官能單體 進行共聚合之化合物之意。此種多官能單體而言，可例舉 :1,4-丁二醇二甲基丙烯酸酯、新戊二醇甲基丙烯酸酯、 乙二醇二甲基丙烯酸酯、二乙二醇二甲基丙烯酸酯、四乙 二醇二甲基丙烯酸酯、丙二醇二甲基丙烯酸酯、四丙二醇 二甲基丙烯酸酯、三羥甲基丙烷三甲基丙烯酸酯、異戊四 〇 醇四甲基丙烯酸酯等多元醇類的甲基丙烯酸酯類，1，4-丁 二醇二丙烯酸酯、新戊二醇二丙烯酸酯、乙二醇二丙烯酸 酯、二乙二醇二丙烯酸酯、四乙二醇二丙烯酸酯、丙二醇 二丙烯酸酯、四丙二醇二丙烯酸酯、三羥甲基丙烷三丙烯 酸酯、異戊四醇四丙烯酸酯等多元醇類的丙烯酸酯類，二 乙烯基苯、二烯丙基苯二甲酸酯等芳香族多官能化合物等 。前述多官能單體，可以單獨使用，亦可組合2種以上使 用。 -18 - 201033644 苯乙烯系單官能單體及能與此進行共聚合之多官能單 體的共聚物，係交聯結構的共聚物，而其凝膠分率較佳爲 10質量％以上。 又，前述苯乙稀系聚合物粒子而言，亦可爲將苯乙稀 系單官能單體/能與此進行共聚合之單官能單體/同樣能進 行共聚合之多官能單體加以共聚合所得之三元系共聚物等 的粒子。 前述苯乙烯系聚合物粒子的折射率，通常爲1.53至 1·61程度，而苯骨架或鹵原子的含有率愈大時，有顯示愈 大的折射率之傾向。又，此種苯乙烯系聚合物粒子，例如 可依懸浮聚合法、微懸浮聚合法、乳化聚合法、分散聚合 法等一般聚合法製造。 前述光擴散粒子的平均粒徑，從能擴散光之同時可充 分均勻分散於透明樹脂中的觀點來看，較佳爲0.5 μιη至 5μπι，更佳範圍爲0.6μιη至3μιη。 再者，上述光擴散粒子的平均粒徑，係依如下述方式 所測定之値（實施例的光擴散粒子的平均粒徑亦同樣）。 亦即，首先，將光擴散劑（光擴散粒子）壓合固定於試料 台上，並實施碳蒸鑛（carbon deposition)以製作試料片 。將此試片採用日立製作所製的電場發射型掃描電子顯微 鏡(field emission scanning electron microscope ) rFE-SEM S-4200」，按1 0000倍至20000倍的放大倍率實施光 擴散劑的SEM (掃描式子顯微鏡）像的觀察及攝影。於所 得光擴散粒子的攝影影像中任意（按無規則方式（random -19 - 201033644 ))選出光擴散粒子40個，並從各影像利用3點圓半徑 法測定此等40個光擴散粒子的粒徑。將如此方式所求得 之40個光擴散粒子的粒徑的平均値，稱爲「平均粒徑」 。亦即，將此等40個光擴散粒子的各粒徑加以合計後， 將此合計値除以40所得之値之意。 又，從即使將光擴散粒子的使用量作成比較少量的使 用量仍能使光充分擴散之觀點來看，前述透明樹脂的折射 率與前述光擴散粒子的折射率的差値的絕對値，較佳爲作 © 成能成爲〇.〇5以上之方式，其中前述折射率的差値的絕 對値，更佳爲作成能成爲0.10以上之方式，又通常前述 折射率的差値的絕對値，則設定爲能成爲0.50以下之方 式。 前述光擴散粒子的使用量，雖視前述透明樹脂的折射 率與前述光擴散粒子的折射率的差値的絕對値之大小、或 作爲目的之光的擴散程度而有異，惟對透明樹脂100質量 份，通常爲〇_〇1至20質量份，較佳爲0.1至10質量份。 © 本發明之光擴散板（3)，係在不妨礙本發明之效果 之範圍內，可含有防帶靜電劑、防氧化劑、加工穩定劑、 紫外線吸收劑、阻燃劑等添加劑。此等添加劑，可分別以 單獨或組合2種以上使用。 第2圖之實施形態中，光擴散板（3)，在來採用由 單層所成之構成，惟亦可採用由2層以上的複層所成之 構成。 例如，前述光擴散板（3 )而言，如第3圖所示，亦 -20- 201033644 可採用由於基層（基底層）（8)的雙面經使表面層（9) (9 )層合一體化所成之構成。前述基層（8 ) ’係由透明 樹脂及光擴散粒子所成，而作爲前述透明樹脂採用當波長 600nm的光透射200mm的光程長時的光線透射率爲65% 以上之透明樹脂之層。亦可採用於前述基層（8)之單面 經使表面層（9)層合一體化之構成。 構成前述表面層（9 )之透明樹脂而言，採用例如對 β構成前述基層（8)之透明樹脂顯示相溶性者，如此透明 樹脂而言，並不特別加以限定，惟可例舉：聚苯乙烯、甲 基丙烯酸甲酯一苯乙烯共聚物、甲基丙烯酸一苯乙烯共聚 物、馬來酸酐一苯乙烯共聚物、聚甲基丙烯酸甲酯、甲基 丙烯酸甲酯一丙烯酸酯共聚物、聚碳酸酯、聚丙烯、聚環 烯烴、環烯烴一α鏈烯烴共聚物等。構成前述表面層（9) 之透明樹脂而言，可爲當波長600nm的光透射200mm的 光程長時的光線透射率在65%以上者，或者例如表面層（ 9 )的厚度（T )係較基層（8 )爲淡薄之情形，則可爲當 波長60〇nm的光透射200mm的光程長時的光線透射率在 6 5 %以下。 在使前述表面層（9)中含有紫外線吸收劑之情形， 此種紫外線吸收劑而言，並不特別加以限定，惟可例舉： 苯并三唑系紫外線吸收劑、二苯基酮系紫外線吸收劑、氰 基丙烯酸酯系紫外線吸收劑、丙二酸酯系紫外線吸收劑、 苯基草酿胺（oxalic anilide)系紫外線吸收劑等。使前述 表面層（9)中含有紫外線吸收劑之結果，即可防止因來 -21 - 201033644 自外部光及光線（2)之光中所含之紫外線等所引起之光 擴散板（3 )之劣化。 前述表面層（9)中，除前述紫外線吸收劑之外，尙 可使其含有：消光劑（matt agent )、光擴散劑（光擴散 粒子）、防帶靜電劑、防氧化劑、加工穩定劑、阻燃劑、 潤滑劑等添加劑。 前述表面層（9)的厚度（T)，通常爲ΙΟμιη至 200μιη ’ 更佳爲 20μιη 至 200μπι，特佳爲 50μπι 至 1 ΟΟμχη ( © 參考第3圖）。 又，前述光擴散板（3)的厚度（S)，通常將設定於 1mm以上（參考第2圖、第3圖）。如厚度在1mm以上 ，則可確保充分的機械性強度。又，爲確保光擴散板（3 )的輕量性起見，前述光擴散板（3)的厚度（S)，較佳 爲設定於5mm以下。 本發明之光擴散板（3)，如係第2圖般的單層構成 之情形，則例如可依擠出成型法（extrusion molding ) 、 ® 注射成型法（injection molding)等方法製造。例如，將 透明樹脂與光擴散粒子加以乾摻和（dry blending)，藉 由加熱而作爲熔融狀態後，依擠出成型法、注射成型法等 通常的成型法成型即可。亦可在製作將光擴散粒子預先與 較少量的透明樹脂一起熔融混練所得粒料（pellet )狀的 母料（master batch )後，將透明樹脂與該母料加以乾摻 和並成型。又’如係第3圖般的複層構成之情形，則可依 共擠壓成型法 （coextrusion molding)、膠接法 （ -22- 201033644 lamination )、熱黏合法（hot gluing )、溶劑黏合法（ solvent gluing)、聚合黏合法（polymerization gluing) 、鑄塑聚合法（cast polymerization )、表面塗佈法（ surface coating)等方法製造。此等製造方法只不過是舉 出其例者，本發明之光擴散板（3)，並不因此等製造方 法所製造者而有所限定。 又，本發明之光擴散板（3)，可爲其表面塗佈有防 ®帶靜電劑者。由於表面塗佈有防帶靜電劑而能防止因靜電 所引起之塵埃的附著以防止因塵埃所引起之光線透射率的 低落之故，可更長期間明亮地照明透射型影像顯示面板（ 液晶面板等）（20)。 再者，本發明之光擴散板（3 )的大小，並不特別加 以限定，係可按照例如作爲目的之面光源裝置（1 )或透 射型影像顯示裝置（30)的大小而適當加以設定者，其中 ，如作成20型（縱長30cm、橫寬40cm)以上大小所設 ® 計之光擴散板則特別合適。 有關本發明之光擴散板（3)，面光源裝置（1)以及 透射型影像顯示裝置（30)，並不因上述實施形態者而有 所限定，祗要是在在申請專利之範圍內而並不超脫本發明 之要旨者則可容許任何設計上之變更。 【實施方式】 [實施例] 其次，就本發明之具體的實施例加以說明’惟本發明 -23- 201033644 並不因此等實施例而有所特別限定。 首先，所使用之第1擠出機、第2擠出機以及T型口 模頭（T-dies)，係如下所示。 第1擠出機：螺桿直徑40mm、單軸式、附有排氣孔 (vent)、田邊塑膠社製 第2擠出機：螺桿直徑40mm、單軸式、附有排氣孔 、田邊塑膠社製 T型口模頭：2種3層多支管式T 口模頭、模唇（lip © )寬幅250mm、三高工程社製。 <原材料> (光擴散劑母料） 將聚苯乙烯（東洋苯乙烯社製「HRM40」）84質量份 、光擴散粒子（羅姆和哈斯社製「巴拉羅伊特EXL5766 j 、交聯丙烯基系聚合物粒子）14質量份、紫外線吸收劑（ 共同藥品社製「生技素譜520」）1質量份、加工穩定劑 © (住友化學社製「速美萊射GP」）1質量份加以乾摻和後 ，採用螺桿直徑65mm的雙軸擠出機在80至250°C下混練 以使其粒料化，製得粒料狀的光擴散劑母料。 (表面層用化合物（compound)) 將甲基丙烯酸甲酯一苯乙烯共聚物（新日鐵化學社製 「MS200NT」）90.9質量份、消光劑（住友化學社製「 XC1A」、交聯丙烯基系聚合物粒子、平均粒徑25μΓη)8 -24- 201033644 質量份、紫外線吸收劑（ADEKA社製「亞德卡斯達夫 L A - 3 1」）1質量份、加工穩定劑（住友化學社製「速美 萊射GP」）0.1質量份加以乾摻和後，採用螺桿直徑 65mm的雙軸擠出機在180至250°C下混練以使其粒料化 ，製得粒料狀的表面層用化合物。 <實施例1 > 將經將 DOW Chemical Company (陶氏化學社製「 STYRON 648」製造廠家處理’按鋅含有率能成爲1〇ppm 以下之方式所調整之聚苯乙烯（鋅係以聚乙烯鋅所含有） 置入260mmx 1 1 Ommx厚度5mm的鑄模內，採用熱加壓機 (hot press )(神島金屬工業所製「新道式ASF型油壓加 壓機」），在成型溫度23(TC下進行熱加壓成型（以 0.3 MPa加壓5分鐘、以2. OMPa加壓3分鐘、以13. OMP a 加壓1分鐘、冷卻5分鐘）後裁切，製得寬幅50mtnx長度 200mmx厚度5mm的透明樹脂板（參考第4圖）。就該透 明樹脂板，依後述之測定法求出T6QQ、T4Q()、Tt (光譜） 、色度X、色度y、色度差。 接著，將前述光擴散劑母料7.5質量份及前述鋅含有 率爲l〇ppm以下之聚苯乙稀（DOW Chemical Company社 製「STYRON 648」）100質量份，飼入第1擠出機的原料 槽（hopper )內，在保持排氣孔部的真空度爲1 〇〇kPa (千 帕）（錶壓）之狀態下在2 0 0至2 5 0 °C下熔融混練後，供 給於經保持在245至25 0°C之T型口模頭。 -25- 201033644 另一方面，將前述表面層用化合物飼入第2擠出機的 原料槽內，在保持排氣孔部的真空度爲lOOkPa (錶壓）之 狀態下在190至25 0°C下熔融混練後，供給於經保持在前 述24 5至250 °C之T型口模頭。 按從前述第1擠出機所供給之樹脂組成物能成爲基層 (8 )，前述第2擠出機所供給之樹脂組成物能成爲表面 層（9) (9)之方式實施共擠出成型，以製作如第3圖所 示之由厚度2.0mm (基層1.9mm、表面層0.0 5 mmx2 )的3 · 層構造的層合板所成之光擴散板（3)。 <實施例2> 除作爲透明樹脂，不用鋅含有率經調整爲1 Oppm以下 之聚乙嫌，而採用經將（DOW Chemical Company社製「 STYRON 648」製造廠家處理，按鋅含有率能成爲lOOppm 之方式所調整之聚苯乙烯（鋅係以硬脂酸鋅所含有）以外 ，其餘則作成與實施例1同樣，製得寬幅50mmx長度 © 200mmx厚度5mm的透明樹脂板之同時，製作由3層構造 之層合板所成光擴散板。 <實施例3> 除作爲透明樹脂，不用鋅含有率經調整爲1 〇PPm以下 之聚乙烯，而採用經將BASF社製「168N」製造廠家處理 ，按鋅含有率能成爲5 Op pm之方式所調整之聚乙烯（鋅係 以硬脂酸鋅所含有）以外，其餘則作成與實施例1同樣， -26- 201033644 製得寬幅50mmx長度200mmx厚度5mm的透明樹脂板之同 時，製作由3層構造之層合板所成光擴散板。 <比較例1 > 除作爲透明樹脂，不用鋅含有率經調整爲1 Oppm以下 之聚乙烯，而採用經將INEOS NOVA Chemicals社製「 Empera3 50N」製造廠家處理，按鋅含有率能成爲70ppm β之方式所調整之聚乙烯以外，其餘則作成與實施例1同樣 ，製得寬幅5〇mmx長度200mmx厚度5mm的透明樹脂板之 同時’製作由3層構造之層合板所成光擴散板。 -27- 201033644201033644 VI. Description of the Invention: [Technical Field] The present invention relates to a light diffusion plate capable of illuminating, for example, a transmitted image display panel, such as a transmissive image display panel, in a brighter and more natural hue. ). [Prior Art] A liquid crystal display device is known as a component of a surface light source device in which a back surface side of a liquid crystal panel (image display unit) including a liquid crystal panel is disposed as a backlight (backlight panel). . In the surface light source device for the backlight, a surface light source device in which a plurality of light sources are disposed in a light box (housing) and a light diffusing plate is disposed on the front side of the light source is known (refer to 曰Japanese Patent Laid-Open Publication No. 2004-197093 (Patent Document 1)). In the above-mentioned light-diffusing sheet, even if the screen size is increased, it is possible to produce a relatively light weight, and it is widely used to disperse light-diffusing particles in a transparent resin. SUMMARY OF THE INVENTION However, such a known light diffusing plate is often in a case where the brightness of the transmissive image display panel or the like is insufficient, or the obtained illumination is not a natural hue. In this case, the light diffusing plate is used. In a transmissive image display device such as a liquid crystal display device, there is a problem in that the brightness of the displayed image is insufficient or it is difficult to obtain a display image of a natural hue. The present invention has been made in view of the above circumstances, and aims to provide a light diffusing plate which can illuminate a transmissive image display panel or the like more brightly. Further, the present invention has an object of providing a light diffusing plate which can illuminate a transmissive image display panel or the like more brightly and with a more natural color tone. The inventors of the present invention have found that the light transmittance of light having a wavelength of 600 nm affects the brightness of illumination, and the zinc compound added during the manufacturing process of the resin is found to be intensive. The fact that the color tone of the illumination has an influence is finally completed. That is, the present invention provides the following means. [1] A light diffusing plate formed of a transparent resin and a light diffusion particle, characterized by light transmittance when light having a wavelength of 600 nm is transmitted through a light pass length of 200 mm. (light transmissivity) is more than 65%. [2] The light-diffusing sheet according to the above [1], wherein the transparent resin contains a composition of a zinc compound, and the content of zinc in the composition is 1 50 ppm or less. [3] The light diffusing plate according to [2], wherein the zinc compound is zinc stearate. [4] The light diffusing plate according to any one of [1] to [3] wherein the transparent resin contains polystyrene. [5] The light-diffusing sheet according to any one of [1] to [4] wherein the light-diffusing particles are selected from the group consisting of propylene-based polymer particles and siloxane-based polymer particles. One or more kinds of polymer particles. [6] The light-diffusing sheet according to any one of [1] to [5] wherein the light-diffusing particles of -6 to 201033644 have an average particle diameter of 0.5 to 5 μm, and the refractive index of the transparent resin and the light The absolute 差 of the difference in refractive index of the diffusing particles is 〇. 5 or more, and the content of the light-diffusing particles per 10,000 parts by mass of the transparent resin is 0.1 to 10 parts by mass. [7] The light source device according to any one of [1] to [6], wherein the light diffusing plate according to any one of [1] to [6], and a plurality of light sources disposed on a back side of the light diffusing plate" A light-diffusing sheet according to any one of the above [1] to [6], wherein the light-diffusing sheet according to any one of the above [1] to [6] is disposed on the back side of the light-diffusing sheet The light source and the transmissive image display panel disposed on the front side of the light diffusing plate. In the invention of [1], the light diffusing plate is made of a transparent resin and a light diffusing particle, and the transparent resin is a light transmittance of 65 % or more when light having a wavelength of 600 nm is transmitted for an optical path length of 200 mm. Therefore, it is possible to illuminate a transmissive image display panel and the like more brightly. In the invention of [2], the transparent resin contains a composition of a zinc compound, and since the content of zinc in the composition is set to 150 ppm or less, the transmission can be transmitted in a more natural color tone. Image display panel, etc. Here, "ppm" means a unit of mass parts per million. In the invention of [3], since the zinc compound is zinc stearate, it is more natural to improve the moldability during molding processing due to the lubricity effect by the zinc stearate lubricant. The tone of the illuminator. In the invention of [4], since the transparent resin contains a structure of polystyrene, transparency is high and illumination can be performed in a more natural color tone. In the invention of the above [5], it is possible to use one or more types of polymer particles selected from the group consisting of propylene-based polymer particles and siloxane-based polymer particles as the light-diffusing particles. Illuminate in brighter, more natural tones. In the invention of [6], the average particle diameter of the light-diffusing particles is 0.5 to 5 μm, and the absolute value of the difference between the refractive index of the transparent resin and the refractive index of the light-diffusing particles is 〇.5 or more. The transparent resin is contained in an amount of 0.1 to 10 parts by mass per 100 parts by mass of the light-diffusing particles, and the light-diffusing particles can be sufficiently uniformly dispersed, and the light-diffusing particles can be sufficiently diffused with a small amount of light-diffusing particles. The advantages. In the invention of [7], a surface light source device capable of brighter illumination can be provided. Further, when the light diffusing plate is provided with the configuration [2], it is possible to provide a surface light source device capable of performing illumination with a brighter and more natural color tone. In the invention of [8], a transmissive image display device capable of obtaining a brighter display image can be provided. Further, when the light diffusing plate has the configuration of [2], it is possible to provide a transmissive ® type image display device capable of obtaining a brighter and more natural color tone. BEST MODE FOR CARRYING OUT THE INVENTION A liquid crystal display device according to one embodiment of the transmissive image display device (30) of the present invention is shown in Fig. 1. In Fig. 1, (30) is a liquid crystal display device, (1 1 ) is a liquid crystal cell '(12) (13) is a polarizing plate, and (1) is a surface light source device (backlight) . On the upper and lower sides -8 - 201033644 of the liquid crystal panel (1 1 ), polarizing plates (12) (13)' are disposed, and the constituent members (11) (12) (13) are used as the transmissive type. The liquid crystal panel (20) of the image display unit. Further, the liquid crystal cell (1 1 ) is formed by sealing a liquid crystal compound between a pair of transparent electrodes. It is preferable that the liquid crystal panel (20) is provided with a color filter or the like to display a color image. Further, the liquid crystal panel (20)' may be configured to have a phase difference plate for adjusting contrast, color tone, and the like when viewed from a oblique direction. The surface light source device (1) is disposed on the lower surface side (back surface side) of the polarizing plate (13) on the lower side of the liquid crystal panel (20). That is, the liquid crystal display device (30) is a direct type liquid crystal display device. The surface light source device (1) includes a lamp box (5) having a rectangular shape when viewed in plan and a thin box shape having no cover on the upper side (front side), and is spaced apart from each other in the lamp holder (5). A plurality of linear light sources (2) arranged in a manner, and a light diffusing plate (3) disposed on an upper side (front side) of the plurality of linear light sources (2). The light diffusing plate (3) is placed and fixed to the lamp holder (5) so as to be able to cover the uncovered surface. Further, a light reflecting layer (not shown) is provided on the inner surface of the lamp cymbal (5). The light source (2) is not particularly limited, but may be, for example, a linear light source such as a cold cathode tube (CCFL), an external electrode fluorescent tube (EEFL), or a flat fluorescent lamp (FFL). A point light source such as a light-emitting diode (201033644 LED) is used. The light diffusing plate (3) is made of a transparent resin and a light diffusing plate, and light diffusing particles are dispersed in the transparent resin. In the present invention, as the above-mentioned transparent resin, a light having a wavelength of 600 nm and a light transmittance of 200 mm or more of a transparent resin having a light transmittance of 65% or more is used. Therefore, if the above-described surface light source device (1) is used, the liquid crystal panel (20) can be illuminated more brightly. Therefore, if the liquid crystal display device (30) is used, the effect of obtaining a brighter display image can be exhibited. Further, in the present embodiment, the transparent resin contains a composition of a zinc compound, and the content of zinc (Zn atom) in the composition is set to 1,500 ppm or less. Therefore, if the above-described surface light source device (1) is used, the liquid crystal panel (20) can be illuminated with a more natural color tone. Therefore, if the liquid crystal display device (30) is used, the effect of obtaining a display image with a more natural hue can be exhibited. Further, in the liquid crystal display device (30), another light diffusion plate may be disposed between the light diffusion plate (3) and the liquid crystal panel (20). Further, an optical member for brightly illuminating the front side may be disposed between the light diffusing plate (3) and the liquid crystal panel (20). The optical member may be, for example, "DBEF" (trade name) manufactured by 3M Company of the United States. For the aforementioned transparent resin, it is suitable for use without coloring. The transparent resin is not particularly limited, and examples thereof include polystyrene, methyl methacrylate monostyrene copolymer, monostyrene methacrylate copolymer-10 - 201033644, and maleic anhydride monophenylene. Ethylene copolymer, polymethyl methacrylate, methyl methacrylate monoacrylate copolymer, polycarbonate, polypropylene, polycycloolefin, cycloolefin-α-olefin copolymer, and the like. Among them, polystyrene, polypropylene, polycycloolefin, and cyclic olefin-α-olefin copolymer are suitable for use from the viewpoint of low hygroscopicity. Further, the transparent resin is a transparent resin having a light transmittance of 65% or more when a light having a wavelength of 600 nm is transmitted through an optical path length of 200 mm. ® thus enhances the illuminance of transmitted light. Among them, the transparent resin is preferably a transparent resin having a light transmittance of 70% or more when a light having a wavelength of 600 Å is transmitted through an optical path length of 200 mm. For example, when a raw material monomer is produced into a transparent resin by a method such as suspension polymerization or dispersion polymerization in a liquid phase, the solvent remaining in the obtained transparent resin, or Catalyst components, additives, and the like added to the solvent may also affect the light transmittance of light having a wavelength of ~600 nm as an impurity. Alternatively, an additive or the like added in a small amount for various purposes due to polymerization of the transparent resin may affect the light transmittance of light having a wavelength of 600 nm as an impurity. Therefore, the "transparent resin having a light transmittance of 65% or more in the optical path length of 200 mm when the light having a wavelength of 600 nm is used in the present invention" is used, for example, the amount of the catalyst or the additive used in the manufacturing process is selected. In the case where the amount of the additive to be added to the transparent resin obtained by the polymerization is small, the amount of the additive to be added to the transparent resin obtained by the polymerization is not sufficient, and it can be obtained. -11 - 201033644 Further, the transparent resin may be a composition containing a zinc compound, but in this case, the zinc content (the content of Zn atoms rather than the content of the zinc compound) in the composition is It is preferably set to 150 ppm or less. When the content of zinc is 1 5 Oppm or less, the content of zinc which is generally considered to have an influence on the color tone is suppressed, so that the transmissive image display panel (20) can be irradiated more naturally. The content of zinc in the composition is preferably set to 90 ppm or less, more preferably 50 ppm or less, and particularly preferably set to 10 ppm or less. ® The zinc compound is not particularly limited, but may, for example, be zinc stearate, zinc laurate, zinc tributyl benzoate, zinc 1,2-hydroxystearate, zinc myristate (Zinc miri state) and so on. Due to the use of the above-mentioned zinc stearate, the lubricity-improving effect can be obtained, and the friction between the transparent resin and the metal surface of the molding machine is lowered by the inclusion of the zinc stearate, and the molding machine is metal-resistant. The prevention of the adhesion of the surface and the improvement of the mold release property are helpful. The content of zinc described above is obtained by the following method (the same applies to the content of zinc in the example of application). That is, the composition containing the zinc compound is taken on a white gold dish, heated with sulfuric acid to heat the organic matter, and then the obtained carbide is ashed at 550 ° C in an electric furnace, and a base is added to the ash. The molten material is melted by heating. Then, the obtained melt was dissolved in nitric acid and water, and adjusted to a predetermined volume to serve as a test solution, and Zn (element) in the test solution was measured by ICP-AES (Induction by Thermo Fisher Scientific) The coupled photoelectron atomic emission spectrometer "iCAP6500" was measured. -12- 201033644 The light-diffusing particles are incompatible with the transparent resin and exhibit a refractive index different from that of the transparent resin, and have diffused light passing through the light diffusing plate (3). The functional particles (including powder) are not particularly limited. For example, the inorganic particles formed by the inorganic material may be organic particles made of an organic material. Such a light-diffusing particle may be used as a surface treatment agent by a surface treatment agent such as a coupling agent. The inorganic material constituting the inorganic particles is not particularly limited, and examples thereof include cerium oxide, calcium carbonate, barium sulfate, titanium oxide, oxyhydroxide, inorganic glass, mica, talc, and white carbon black (white). Carbon ), magnesium oxide, zinc oxide, and the like. The organic material constituting the organic particles is not particularly limited, and examples thereof include a propylene-based polymer, a chopping-house polymer, and a styrene-based polymer. Among these, from the viewpoint that the light diffusing plate can be made lighter while the illuminance is increased due to less impurities, it is preferable to use organic particles, and particularly suitable are propylene-based polymer particles and helium oxygen. Alkane polymer particles. The propylene-based polymer particles may be a polymer having a propylene-based monofunctional monomer unit as a main component, that is, a polymer containing 50% by mass or more of a propylene-based monofunctional monomer unit. . The particles containing the polymer of 50% by mass or more of the propylene-based monofunctional monomer unit may be particles of a polymer of the propylene-based monofunctional monomer unit in all (100% by mass) of the monomer unit. It may be a particle of a copolymer of a propylene-based monofunctional monomer-13-201033644 and a monofunctional monomer copolymerizable therewith. The propylene-based monofunctional monomer may, for example, be acrylic acid, methacrylic acid, acrylate or methacrylate. The acrylate is not particularly limited, and may, for example, be methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate or 2-ethylhexyl acrylate. 2-hydroxyethyl acrylate or the like. Further, the methacrylate is not particularly limited, and examples thereof include methyl methacrylate, ethyl methacrylate, butyl methacrylate, and methyl hexyl hexacarboxylate. Phenyl acrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate, and the like. These acryl-based monofunctional monomers may be used singly or in combination of two or more. The monofunctional monomer capable of copolymerizing with the aforementioned propylene-based monofunctional monomer has one double bond capable of radical polymerization in the molecule, and can be carried out with the double bond and the propylene-based monofunctional monomer. Copolymerized compound. Specifically, 'for example, in addition to styrene, a substituted styrene such as a halogenated styrene such as chlorostyrene or bromostyrene, an alkyl group such as vinyl toluene or α-methylstyrene, or a styrene may be mentioned. Wait. Further, acrylonitrile can also be mentioned. These monofunctional monomers ' may be used singly or in combination of two or more. The propylene-based polymer particles are in the case of all of the monomer units (1% by mass) of the particles of the polymer of the propylene-based monofunctional monomer unit, and the 'acryl-based monofunctional monomer and energy In the case of the particles of the copolymer of the monofunctional monomer copolymerized, the weight average molecular weight is preferably from 500,000 to 5,000,000. Further, the propylene base polymer particles may be particles of a copolymer of a propylene group -14 - 201033644 monofunctional monomer and a polyfunctional monomer copolymerizable therewith. Such a polyfunctional monomer means two or more double bonds capable of copolymerizing with a propylene-based monofunctional monomer in the molecule, and can be copolymerized with the propylene-based monofunctional monomer by such a double bond. The meaning of the compound. The polyfunctional monomer may, for example, be a methacrylate-based polyhydric alcohol acrylate or aromatic polyfunctional compound similar to the above-mentioned styrene polymer particles. Compounds, etc. These polyfunctional monomers may be used singly or in combination of two or more. The copolymer of an acryl-based monofunctional monomer and a polyfunctional monomer copolymerizable therewith is a copolymer of a bridge structure, and the gel fraction thereof is preferably 10 More than mass%. Further, the propylene-based polymer particles may be obtained by copolymerizing a propylene-based monofunctional monomer/a monofunctional monomer copolymerizable with the same/copolymerizable polyfunctional monomer. A particle such as a ternary copolymer. § The refractive index of the propylene-based polymer particles is usually from about 1.46 to 1.55', and the larger the content of the benzen skeleton or the _ atom, the more the refractive index tends to be exhibited. Further, such propylene-based polymer particles can be produced, for example, by a general polymerization method such as suspension polymerization, micro suspension polymerization, emulsion polymerization, or dispersion polymerization. The above-mentioned siloxane polymer-based polymer particles can be produced, for example, by a method in which a chlorodecane is hydrolyzed and condensed. The chlorodecanes -15-201033644' may, for example, be dimethyldichlorodecane, diphenyldichlorodecane, phenylmethyldichlorodecane, methyltrichlorodecane or phenyltrichlorodecane. The above siloxane polymer may be a crosslinked person. For example, when it is crosslinked, for example, a paraxane-based polymer, such as benzamidine peroxide, 2,4-dichlorobenzidine peroxide, p-chlorobenzothymidine peroxide, or peroxide A peroxide such as an anisyl group or a dibutylbutyl-2,5-dimethyl-2,5-di(t-butylperoxy)hexane may be used. Further, in the case where a structure having a stanol group at the terminal is to be formed, it is condensed and crosslinked with a alkyl decane (© condensation bridging). The crosslinked rhodium-based polymer ' is preferably a structure in which two to three organic groups are bonded per one deuterium atom. Such a decane-based polymer is also referred to as a polymer of a polyoxyxene rubber or a polyoxymethylene resin. The siloxane model is preferably one which is solid at normal temperature. The aerobic system polymer particles are obtained by, for example, pulverizing the aerobic system polymer. A curable polymer having a linear organosiloxane block or a composition thereof can be obtained by hardening it in a spray state to form a granulated particle (refer to Japanese Patent Laid-Open No. 5 9-68 3 3 Bulletin 3). Further, an alkyltrialkoxide or a partially hydrolyzed condensate thereof may be obtained by subjecting it to a hydrolytical condensation in an aqueous solution of ammonia or an amine to prepare a granulated particle (refer to Japanese Patent Special). Kai Zhao 60- 1 3 8 1 3 bulletin). The aerobic polymer polymer particles preferably have a weight average molecular weight of from 500,000 to 5,000,000. In the case where the azeosiloxane-based polymer is a crosslinked structure of -16 to 201033644, the gel fraction is preferably 1% by mass or more. The refractive index of the above siloxane polymer particles is usually from about 1.40 to 1.47. The styrene polymer particles may be a polymer containing a styrene-based monofunctional monomer unit as a main component, that is, a polymer containing 50% by mass or more of a styrene-based monofunctional monomer unit. . The particles containing the polymer of 50% by mass or more of the styrene-based monofunctional monomer unit may be particles of a polymer of all of the monomer units (100% by mass) of the styrene-based mono-functional monomer unit. It may also be a particle of a copolymer of a styrene-based monofunctional monomer and a monofunctional monomer copolymerizable therewith. The styrene-based monofunctional monomer has a styrene skeleton and a compound having one double bond capable of undergoing radical polymerization in the molecule. Specifically, for example, in addition to styrene, hydrazine may be mentioned instead of styrene. The above-mentioned substituted styrene may, for example, be a halogenated styrene such as chlorostyrene or bromostyrene, an alkylstyrene such as vinyltoluene or α-methylstyrene, or the like. The monofunctional monomer copolymerizable with the styrene-based monofunctional monomer has one double bond capable of radical polymerization in the molecule, and can be co-polymerized with the styrene-based monofunctional monomer. Polymerized compound. Specifically, methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, methacrylic acid 2- Ethyl acrylate such as ethyl hexyl ester or 2-hydroxyethyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethyl acrylate An acrylate such as hexyl ester or 2-hydroxyethyl acrylate, acrylonitrile or the like. These monofunctional monomers may be used singly or in combination of two or more kinds -17- 201033644. Among them, a monofunctional monomer which can be copolymerized with the above styrene-based monofunctional monomer is preferably a methacrylate. The styrene-based polymer particles are all of the monomer units (丨00% by mass) of the particles of the polymer of the styrene-based monofunctional monomer unit, and the 'styrene-based monofunctional monomer and can be used here. In the case of the particles of the copolymer of the copolymerized monofunctional monomer, the weight average molecular weight thereof is preferably from 500,000 to 5,000,000. Further, the styrene polymer particles may be particles of a copolymer of a styrene-based monofunctional monomer and a polyfunctional monomer copolymerizable therewith. Such a polyfunctional monomer means a compound having two or more double bonds capable of undergoing radical polymerization in the molecule and capable of copolymerizing the double bond with a styrene monofunctional monomer. Such a polyfunctional monomer may, for example, be 1,4-butanediol dimethacrylate, neopentyl glycol methacrylate, ethylene glycol dimethacrylate or diethylene glycol dimethacrylate. Acrylate, tetraethylene glycol dimethacrylate, propylene glycol dimethacrylate, tetrapropylene glycol dimethacrylate, trimethylolpropane trimethacrylate, isovaleryl tetramethacrylate Polyols such as methacrylates, 1,4-butanediol diacrylate, neopentyl glycol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, tetraethylene glycol Acrylates of polyhydric alcohols such as acrylate, propylene glycol diacrylate, tetrapropylene glycol diacrylate, trimethylolpropane triacrylate, and isopentaerythritol tetraacrylate, divinylbenzene, diallyl benzene An aromatic polyfunctional compound such as a formate or the like. These polyfunctional monomers may be used singly or in combination of two or more. -18 - 201033644 A copolymer of a styrene-based monofunctional monomer and a polyfunctional monomer copolymerizable therewith is a copolymer of a crosslinked structure, and the gel fraction thereof is preferably 10% by mass or more. Further, the styrene-based polymer particles may be a styrene-based monofunctional monomer/a monofunctional monomer copolymerizable therewith/a polyfunctional monomer which can be copolymerized in the same manner. The particles of the obtained ternary copolymer or the like are polymerized. The refractive index of the styrene polymer particles is usually about 1.53 to 1.61, and the larger the content of the benzene skeleton or the halogen atom, the higher the refractive index tends to be. Further, such styrene polymer particles can be produced, for example, by a general polymerization method such as a suspension polymerization method, a microsuspension polymerization method, an emulsion polymerization method or a dispersion polymerization method. The average particle diameter of the light-diffusing particles is preferably from 0.5 μm to 5 μm, and more preferably from 0.6 μm to 3 μm from the viewpoint of being able to uniformly disperse uniformly in the transparent resin while diffusing light. Further, the average particle diameter of the light-diffusing particles is measured by the following method (the average particle diameter of the light-diffusing particles of the examples is also the same). That is, first, a light diffusing agent (light diffusing particles) is press-fitted to a sample stage, and carbon deposition is performed to prepare a sample piece. This test piece was subjected to a field emission scanning electron microscope (RFE-SEM S-4200) manufactured by Hitachi, Ltd., and the SEM of the light diffusing agent was performed at a magnification of 10,000 times to 20,000 times. Microscope) observation and photography. In the photographic image of the obtained light-diffusing particles, 40 light-diffusing particles were randomly selected (in random manner (random -19 - 201033644)), and the particles of the 40 light-diffusing particles were measured from each image by a 3-point circular radius method. path. The average enthalpy of the particle diameters of the 40 light-diffusing particles obtained in this manner is referred to as "average particle diameter". That is, after the total particle diameters of the 40 light-diffusing particles are totaled, the total is divided by 40. Moreover, the absolute enthalpy of the difference between the refractive index of the transparent resin and the refractive index of the light-diffusing particle is obtained from the viewpoint that the amount of the light-diffusing particles used is relatively small, and the light can be sufficiently diffused.佳为作成成成成〇5〇 or more, wherein the absolute 値 of the difference in refractive index is more preferably a form of 0.10 or more, and usually the absolute 値 of the difference in refractive index is It is set to be 0.50 or less. The amount of use of the light-diffusing particles differs depending on the absolute value of the difference between the refractive index of the transparent resin and the refractive index of the light-diffusing particles, or the degree of diffusion of the intended light, but the transparent resin 100 The parts by mass are usually from 1 to 20 parts by mass, preferably from 0.1 to 10 parts by mass. The light diffusing plate (3) of the present invention may contain an antistatic agent, an antioxidant, a processing stabilizer, an ultraviolet absorber, a flame retardant or the like insofar as it does not impair the effects of the present invention. These additives may be used alone or in combination of two or more. In the embodiment of Fig. 2, the light diffusing plate (3) is formed of a single layer, but it may be formed of two or more layers. For example, in the foregoing light diffusing plate (3), as shown in FIG. 3, also -20-201033644, the surface layer (9) (9) may be laminated due to the double-sided surface of the base layer (base layer) (8). The composition of integration. The base layer (8)' is made of a transparent resin and light-diffusing particles, and a layer of a transparent resin having a light transmittance of 65% or more when the light having a wavelength of 600 nm is transmitted for an optical path length of 200 mm is used as the transparent resin. It is also possible to adopt a configuration in which the surface layer (9) is laminated and integrated on one side of the base layer (8). The transparent resin constituting the surface layer (9) exhibits compatibility with, for example, a transparent resin constituting the base layer (8), and the transparent resin is not particularly limited, but may be exemplified by polyphenylene. Ethylene, methyl methacrylate monostyrene copolymer, monostyrene methacrylate copolymer, maleic anhydride monostyrene copolymer, polymethyl methacrylate, methyl methacrylate monoacrylate copolymer, poly Carbonate, polypropylene, polycycloolefin, cycloolefin-α-olefin copolymer, and the like. The transparent resin constituting the surface layer (9) may have a light transmittance of 65% or more when the light having a wavelength of 600 nm is transmitted for an optical path length of 200 mm, or for example, the thickness (T) of the surface layer (9) is higher than the base layer. (8) In the case of a thin condition, the light transmittance when the light having a wavelength of 60 〇 nm is transmitted for an optical path length of 200 mm may be 65 % or less. In the case where the surface layer (9) contains an ultraviolet absorber, the ultraviolet absorber is not particularly limited, and examples thereof include a benzotriazole-based ultraviolet absorber and a diphenylketone-based ultraviolet absorber. An absorbent, a cyanoacrylate ultraviolet absorber, a malonate ultraviolet absorber, an oxalic anilide ultraviolet absorber, or the like. As a result of the ultraviolet absorbing agent contained in the surface layer (9), it is possible to prevent the light diffusing plate (3) caused by ultraviolet rays contained in the light from the external light and the light (2) from 21 to 201033644. Deterioration. In the surface layer (9), in addition to the ultraviolet absorber, the ruthenium may contain: a matt agent, a light diffusing agent (light diffusing particles), an antistatic agent, an antioxidant, a processing stabilizer, Additives such as flame retardants and lubricants. The thickness (T) of the surface layer (9) is usually ΙΟμηη to 200μηη', more preferably 20μηη to 200μπι, and particularly preferably 50μπι to 1 ΟΟμχη (refer to Fig. 3). Further, the thickness (S) of the light diffusing plate (3) is usually set to 1 mm or more (refer to Figs. 2 and 3). If the thickness is 1 mm or more, sufficient mechanical strength can be ensured. Further, in order to ensure the light weight of the light diffusing plate (3), the thickness (S) of the light diffusing plate (3) is preferably set to 5 mm or less. In the case where the light-diffusing sheet (3) of the present invention has a single-layer structure as shown in Fig. 2, for example, it can be produced by a method such as extrusion molding or injection molding. For example, the transparent resin and the light-diffusing particles are dry blended, and after being heated, they are melted, and then molded by a usual molding method such as an extrusion molding method or an injection molding method. Alternatively, a master batch obtained by melt-kneading the light-diffusing particles together with a relatively small amount of a transparent resin may be prepared, and then the transparent resin and the master batch may be dry-blended and molded. In the case of the composite layer structure as shown in Fig. 3, it can be coextrusion molding, bonding method (-22-201033644 lamination), hot gluing, solvent adhesion. (solvent gluing), polymerization gluing, cast polymerization, surface coating, etc. These manufacturing methods are merely examples, and the light diffusing plate (3) of the present invention is not limited by the manufacturer of the manufacturing method. Further, the light diffusing plate (3) of the present invention may be coated with an antistatic agent. Since the surface is coated with an antistatic agent to prevent the adhesion of dust due to static electricity to prevent the light transmittance due to dust from being lowered, the transmissive image display panel can be brightly illuminated for a longer period of time (liquid crystal panel) Etc) (20). Further, the size of the light diffusing plate (3) of the present invention is not particularly limited, and may be appropriately set in accordance with, for example, the size of the intended surface light source device (1) or the transmissive image display device (30). Among them, a light diffusing plate made of a size of 20 or more (length 30 cm, width 40 cm) or more is particularly suitable. The light diffusing plate (3) of the present invention, the surface light source device (1) and the transmissive image display device (30) are not limited by the above embodiments, and are intended to be within the scope of the patent application. Any design changes may be tolerated without departing from the gist of the invention. [Embodiment] [Embodiment] Next, a specific embodiment of the present invention will be described. However, the present invention -23-201033644 is not particularly limited as such. First, the first extruder, the second extruder, and the T-dies used are as follows. The first extruder: a screw diameter of 40 mm, a single-axis type, a vent, and a second extruder made by Tanabe Plastics Co., Ltd.: screw diameter 40 mm, single-axis type, with vent hole, Tanabe Plastics Co., Ltd. T-die die: 2 kinds of 3-layer multi-tube T-die, lip (lip ©) width 250mm, manufactured by Sangao Engineering Co., Ltd. <Materials> (Light diffusing agent masterbatch) 84 parts by mass of polystyrene ("HRM40" manufactured by Toyo Styrene Co., Ltd.) and light-diffusing particles ("Barra Royt EXL5766 j, manufactured by Roma and Haas" 14 parts by mass of the cross-linked propylene-based polymer particles, and 1 part by mass of the ultraviolet absorber ("Biochemicals Spectrum 520" manufactured by Kyoritsu Co., Ltd.), processing stabilizers ("Summer Chemicals GP" manufactured by Sumitomo Chemical Co., Ltd.) After 1 part by mass was dry blended, it was kneaded by a twin-screw extruder having a screw diameter of 65 mm at 80 to 250 ° C to pelletize it to obtain a pellet-shaped light diffusing agent master batch. (a compound for a surface layer) 90.9 parts by mass of a methyl methacrylate monostyrene copolymer ("MS200NT" manufactured by Nippon Steel Chemical Co., Ltd.), a matting agent ("XC1A" manufactured by Sumitomo Chemical Co., Ltd., a crosslinked propylene group) Polymer particles, average particle size 25μΓη) 8 -24- 201033644 parts by mass, UV absorber ("Adekasdav LA-3" manufactured by ADEKA Co., Ltd.), 1 part by mass, processing stabilizer (manufactured by Sumitomo Chemical Co., Ltd.) After the dry blending was carried out in 0.1 mass parts, a 200-mm screw twin-screw extruder was used to knead at 180 to 250 ° C to pelletize it to obtain a pellet-like surface layer. Compound. <Example 1 > Polystyrene adjusted by the DOW Chemical Company ("STYRON 648" manufactured by The Dow Chemical Co., Ltd." in a zinc content of 1 〇 ppm or less It is contained in a mold of 260 mm x 1 1 Ommx and a thickness of 5 mm, and a hot press ("New Road type ASF type hydraulic press" manufactured by Shinto Metal Industry Co., Ltd.) is used at a molding temperature of 23 (Temperature pressurization was carried out under TC (pressing at 0.3 MPa for 5 minutes, pressing at 2. OMPa for 3 minutes, pressing with 1. OMP a for 1 minute, cooling for 5 minutes), and then cutting to obtain a width of 50 mtnx. 200 mm x a transparent resin plate having a thickness of 5 mm (refer to Fig. 4). The transparent resin plate was subjected to measurement methods described below to obtain T6QQ, T4Q(), Tt (spectrum), chromaticity X, chromaticity y, and chromaticity difference. Then, 7.5 parts by mass of the light diffusing agent masterbatch and 100 parts by mass of polystyrene ("STYRON 648" manufactured by DOW Chemical Co., Ltd.) having a zinc content of 1 〇 ppm or less were fed to the first extruder. In the hopper, the vacuum in the vent hole is 1 kPa (kPa) (gauge) In the state of melt-kneading at 200 to 250 ° C, it is supplied to a T-die which is maintained at 245 to 25 ° C. -25- 201033644 On the other hand, the aforementioned surface layer is compounded with a compound. In the raw material tank of the second extruder, after the vacuum degree of the vent hole portion is maintained at 100 kPa (gauge pressure), the mixture is melted and kneaded at 190 to 205 ° C, and then supplied to the above-mentioned 24 5 to T-die die at 250 ° C. The resin composition supplied from the first extruder can be a base layer (8), and the resin composition supplied from the second extruder can be a surface layer (9) (9) A co-extrusion molding was carried out to produce a light-diffusing sheet made of a laminate having a thickness of 2.0 mm (base layer 1.9 mm, surface layer 0.05 mm×2) as shown in Fig. 3 ( 3). <Example 2> In addition to being a transparent resin, it is not necessary to adjust the zinc content to a concentration of 10 ppm or less, and it is treated by a manufacturer of "STYRON 648" manufactured by DOW Chemical Company, and the zinc content can be obtained. A polystyrene sheet having a width of 50 mm x length of 200 mm x a thickness of 5 mm was produced in the same manner as in Example 1 except that polystyrene adjusted in a manner of 100 ppm was used (zinc is contained in zinc stearate). The light-diffusing board formed by the laminate of the three-layer structure. <Example 3> In addition to the transparent resin, the polyethylene having a zinc content of 1 〇 ppm or less is not used, and the 168N manufacturer manufactured by BASF Co., Ltd. is used, and the zinc content can be 5 Op pm. The polyethylene adjusted in the manner (zinc is contained in zinc stearate) was prepared in the same manner as in Example 1, and -26-201033644 was obtained by producing a transparent resin sheet having a width of 50 mm x a length of 200 mm and a thickness of 5 mm. The light-diffusing board formed by the laminate of the three-layer structure. <Comparative Example 1 > In addition to the transparent resin, the polyethylene having a zinc content of 1 Oppm or less was not used, and the product of the "empera 3 50N" manufactured by INEOS NOVA Chemicals Co., Ltd. was used, and the zinc content was 70 ppm. In the same manner as in the first embodiment, a polyethylene resin having a width of 5 mm, a length of 200 mm, and a thickness of 5 mm was produced, and a light-diffusing sheet made of a laminate having a three-layer structure was produced. . -27- 201033644
4>< i m tog — -⑼ m 14- CO 卜 o oo ?; tl 翻 〇 〇 〇 〇 _ Μ 0.01 g 0.01 s ¢1 〇 o >s m CN m 0.331 T-H <N CO 〇\ cs 迎 〇 〇 o lilii m 施 πυ Μ X m m m ΓΊ m to m 〇\ CN ¢3 c5 ο o o § S 77.6 77.5 81.7 46.6 m R \q (N 寸 OS ^ v〇 oo S3 2 8 in 00 »n s I 3 Ά 〇 透明樹脂 W 蚺 Φ N 敬 z$ 〇 〇 騷 m tlmil w K) K) K) Κ) 鋰 m 擗 擀 被 擗 嵌 嵌 m «-π CN m m 辑 辑 揭 Κ κ JJ 201033644 就如上述方式所得各透明樹脂板，依下％ '測@ s，$ 出T6G。、T4G()、Tt (光譜）、色度X、色度y、色度差。又 ，就如上述方式所得各光擴散板，依下述評價法，求出光 線透射率（Tt)及平均亮度差。將此等結果，表示於表1 中〇 <波長600nm的光在光程長200mm當中之光的光線透射率 β的測定法•波長4〇〇nm的光在光程長20〇mm當中之光的 光線透射率的測定法•透明樹脂板的光線透射率（Tt)的 測定法> 將所得透明樹脂板（寬幅50mmx長度200mmx厚度 5mm)的4個側面（51)使用硏磨機（朝日美加樂社製「 普拉彼蒂1 000」）加以硏磨以製作測定試驗片（50)(參 考第4圖）。就該測定試驗片，採用日立製作所製塑膠特 性測定系統（係由U-4000型光譜光度計及大型試料室積 分球（integrated sphere)附屬裝置所構成者），以測定 波長600nm的光透射200mm的光程長時的光線透射率（ T60。）。又，同樣方式，測定當波長4〇〇nm的光透射 200mm的光程長時的光線透射率（Too )。又，同樣測定 在200mm的光程長當中之光線透射率Tt (波長3 80至 78Onm的光的光線透射率的算術平均値）。 <色度 X及色度 y的測定法·色度差（chromaticity difference)之算出法> -29- 201033644 就上述測定試驗片採用日立製作所製塑膠特性測定系 統（係由U-4000型光譜光度計及大型試料室積分球附屬 裝置所構成者），以測定透射光的色度X及色度y。光譜 光度計的光源色度爲X = 0.3100、y=〇.3161，而藉由此「光 源色度」與「透射光的色度」的色度差{(Δχ) 2+(Ay) 2}1/2而評價該透明樹脂的色度（是否自然的色調）。亦即 ，如該色度差愈小，則愈能使來自光源之光以更自然的色 調朝向前方照明。 ® <成型性評價法> 如藉由熱加壓成型而製作透明樹脂板時，則將無對熱 加壓機的金屬面的樹脂附著，且脫模性亦良好者作爲「〇 」，將有對熱加壓機的金屬面的樹脂附著，且脫模型亦不 佳者作爲「X」。4>< im tog — -(9) m 14- CO 卜 o oo ?; tl 〇〇〇〇 〇〇〇〇 g 0.01 g 0.01 s ¢1 〇o >sm CN m 0.331 TH <N CO 〇\ cs 〇o lilii m πυ Μ X mmm ΓΊ m to m 〇\ CN ¢3 c5 ο oo § S 77.6 77.5 81.7 46.6 m R \q (N inch OS ^ v〇oo S3 2 8 in 00 »ns I 3 Ά 〇 Transparent resin W 蚺Φ N 敬 z $ 〇〇 m m tlmil w K) K) K) Κ) Lithium m 擗擀 is embedded in the m «-π CN mm Collection κ JJ 201033644 As obtained above Transparent resin board, according to % 'test @ s, $ out of T6G. , T4G (), Tt (spectrum), chromaticity X, chromaticity y, chromaticity difference. Further, as in each of the light-diffusing sheets obtained as described above, the optical transmittance (Tt) and the average luminance difference were obtained by the following evaluation methods. These results are shown in Table 1. The measurement of the light transmittance β of light with a wavelength of 600 nm in the optical path length of 200 mm • The light having a wavelength of 4 〇〇 nm is in the optical path length of 20 〇 mm. Method for Measuring Light Transmittance of Light • Method for Measuring Light Transmittance (Tt) of Transparent Resin Plate> Four side faces (51) of the obtained transparent resin plate (width 50 mm x length 200 mm x thickness 5 mm) were used using a honing machine ( The "Purabiti 1 000" manufactured by Asahi Mejiale Co., Ltd. was honed to prepare a test piece (50) (refer to Fig. 4). For the measurement test piece, a plastic property measurement system (manufactured by a U-4000 spectrophotometer and a large-scale integrated sphere attachment device) manufactured by Hitachi, Ltd. was used to measure light having a wavelength of 600 nm and a transmission of 200 mm. Light transmittance (T60.) when the optical path is long. Further, in the same manner, the light transmittance (Too) when the light having a wavelength of 4 〇〇 nm was transmitted for an optical path length of 200 mm was measured. Further, the light transmittance Tt (the arithmetic mean 値 of the light transmittance of light having a wavelength of 3 80 to 78 Onm) in the optical path length of 200 mm was also measured. <Measurement of chromaticity X and chromaticity y and calculation method of chromaticity difference> -29- 201033644 The above-mentioned measurement test piece was subjected to a plastic characteristic measurement system manufactured by Hitachi, Ltd. (by U-4000 type spectrum) A photometer and a large sample chamber integrating sphere attachment device are used to measure the chromaticity X and chromaticity y of the transmitted light. The chromaticity of the source of the spectrophotometer is X = 0.3100, y = 〇.3161, and the chromaticity difference between the "source chromaticity" and the "chromaticity of transmitted light" {(Δχ) 2+(Ay) 2} The chromaticity (whether or not the natural color tone) of the transparent resin was evaluated 1/2. That is, as the chromaticity difference is smaller, the light from the light source is illuminated toward the front with a more natural color tone. ® <Formability Evaluation Method> When a transparent resin sheet is produced by hot press molding, the resin on the metal surface of the heat press machine is not adhered, and the mold release property is also good as "〇". There is a resin attached to the metal surface of the hot press machine, and the model is also inferior as "X".
<光擴散板的光線透射率（Tt)之測定法> G 就所得光擴散板，採用村上色彩技術硏究所製的透射 •反射率計HR-100型，並依據JIS K7136以測定光線透 射率（Tt)。 (平均亮度差（average luminance difference)(與比較 例1的亮度差）之評價法> 將如上述方式所得之光擴散板，按擠出方向（MD( 機器方向）方向）成爲長11 0mm、與此垂直相交之方向成 -30- 201033644 爲寬110mm之方式裁切爲正方形之方式，製得評價試驗 片。接著，從20吋型的液晶電視拆卸液晶面板，各種光 學薄膜以及光擴散板後，將此光擴散板的中央部，挖出 llOmmx 11 Omm的正方形狀，並於此挖取部分安裝上述光 擴散板（實施例品、比較例品）的評價試驗片，使其頂接 於前述拆卸後的燈匣（於內部按互相離間之方式配置有複 數支螢光燈）的邊框部的前面之狀態下配置固定以堵塞燈 ®匣的無蓋面。然後，於此光擴散板的前面側層合市售的光 擴散薄膜2片，再於其前面側層合亮度提升薄膜（美國 3M社製「DBEF (反射型偏光薄膜」）1片，在點亮螢光 燈之狀態下，採用亮度測定計（阿伊•系統（股）製「 Eye Scale-3W」、多點亮度計（multipoint luminance meter))以測定其亮度。 再者，前述亮度測定，係如下述方式實施者。亦即， 於恆溫恆濕（溫度25.0°C、濕度50· 0%)的暗房內的地板 β面上，按將其前面側作爲上面（按背面能頂接於地板面之 方式）配置液晶電視，並按能拍攝液晶電視的前面的全面 之方式於液晶電視的上方位置，往朝下之方向配置攝影機 。此時，從液晶電視的前面至攝影機的距離作成120.0cm ，將亮度測定計的測定條件設定爲SPEED (感光速度）： 1 /250、GAIN (增益）：3、光圏：16，並將液晶電視的前 面的全範圍指定爲測定光點（measurement spot)以分別 測定在各測定光點（51 x5 1=2601處）的亮度，並將此等 亮度的平均値作爲平均亮度（Cd/m2(新燭光/公尺2))。 201033644 平均亮度差（％)={(實施例的平均亮度）-(比較例1的平 均亮度）}/(比較例1的平均亮度） 藉由從上述計算式所求得之平均亮度差（％)而加以 評價。 由表1可知，由於本發明之實施例1至3的光擴散板 ，係透明樹脂的1'6〇〇在65%以上之故，較1'6〇〇在30.9%之 比較例1的光擴散板之平均亮度爲高，因而能更明亮地照 明例如透射型影像顯示面板等。 © 再者，由於實施例1至3的光擴散板，係透明樹脂（ 聚苯乙烯）中的鋅的含有率在15 Oppm以下之故，色度差 小，能以更自然的色調照明例如透射型影像顯示面板等。 其中，由於透明樹脂中的鋅的含有率在5〇ppm以下之實施 例1及實施例3的光擴散板，係色度差特小之故’能以更 加自然的色調照明透射型影像顯示面板等。 [產業上之利用可能性] ® 本發明之光擴散板，係很適合採用爲面光源裝置用的 光擴散板者，惟並不特別加以限定於此種用途。又，本發 明之面光源裝置，係很適合採用爲透射型影像顯示裝置用 的backlight者，惟並不特別加以限定於此種用途。 【圖式簡單說明】 第1圖，係表示有關本發明之透射型影像顯示裝置的 一實施形態之模式圖 -32- 201033644 第2圖’係表示有關本發明之光擴散板的一實施形態 之剖面圖。 第3圖’係表示有關本發明之光擴散板的另一實施形 態之剖面圖。 第4圖，係在光程長200mm中的波長6〇〇nm的光的 光線透射率之測定法的說明圖。 ®【主要元件符號說明】 1 :面光源裝置 2 :光源 3 :光擴散板 20:透射型影像顯示面板 30:透射型影像顯示裝置（液晶顯示裝置） ❹ -33-<Measurement of Light Transmittance (Tt) of Light-Diffusing Plate> G For the light-diffusing sheet obtained, a transmission/reflectance meter HR-100 manufactured by Murakami Color Technology Co., Ltd. was used, and light was measured in accordance with JIS K7136. Transmittance (Tt). (Evaluation method of average luminance difference (difference from luminance of Comparative Example 1)> The light diffusion plate obtained as described above was formed to have a length of 11 mm in the extrusion direction (MD (machine direction) direction). The direction perpendicular to this is -30-201033644 and the width is 110 mm. The test piece is obtained by cutting into a square. Then, the liquid crystal panel, various optical films, and the light diffusing plate are removed from the 20-inch LCD TV. The central portion of the light-diffusing sheet was dug out of a square shape of 11 mm × 11 mm, and an evaluation test piece of the light-diffusing sheet (example product, comparative example) was attached to the portion to be attached thereto. The front side of the frame portion of the detached lamp 匣 (the plurality of fluorescent lamps are disposed inside each other) is fixed to block the uncovered surface of the lamp 匣. Then, the front side of the light diffusing plate Two sheets of a commercially available light-diffusing film were laminated, and a brightness-enhancing film ("DBEF (reflective polarizing film)" manufactured by 3M Company, USA) was laminated on the front side thereof, and light was used in the state of lighting the fluorescent lamp. The degree meter (Ayen System Co., Ltd. "Eye Scale-3W", multipoint luminance meter) is used to measure the brightness. The brightness measurement is performed as follows. , on the floor β surface in a dark room with constant temperature and humidity (temperature 25.0 ° C, humidity 50·0%), the LCD TV is placed with the front side as the top (the back side can be connected to the floor surface), and Set the camera in the direction of the upper side of the LCD TV, and set the camera in the downward direction. At this time, the distance from the front of the LCD TV to the camera is set to 120.0 cm, and the measurement conditions of the brightness meter are set. For SPEED: 1 / 250, GAIN: 3, aperture: 16, and specify the full range of the front of the LCD TV as the measurement spot to measure each measurement spot ( The brightness of 51 x 5 1 = 2601), and the average 値 of these brightnesses is taken as the average brightness (Cd/m2 (new candle light / meter 2)). 201033644 Average brightness difference (%) = {(the average brightness of the embodiment) )-(Comparative Example 1 Luminance)}/(the average luminance of Comparative Example 1) was evaluated by the average luminance difference (%) obtained from the above calculation formula. As is apparent from Table 1, the light diffusion sheets of Examples 1 to 3 of the present invention are known. The 1'6〇〇 of the transparent resin is 65% or more, and the average brightness of the light diffusing plate of Comparative Example 1 is higher than that of 1'6〇〇 at 30.9%, so that, for example, a transmissive image can be illuminated more brightly. Display panel, etc. © In the light diffusing plate of Examples 1 to 3, the content of zinc in the transparent resin (polystyrene) is 15 Oppm or less, and the chromaticity difference is small, so that it can be more natural. Hue illumination such as a transmissive image display panel or the like. In the light diffusing plates of Examples 1 and 3 in which the content of zinc in the transparent resin is 5 〇 ppm or less, the chromaticity difference is extremely small, so that the transmissive image display panel can be illuminated with a more natural color tone. Wait. [Industrial Applicability] The light diffusing plate of the present invention is suitably used as a light diffusing plate for a surface light source device, but is not particularly limited to such use. Further, the surface light source device of the present invention is suitably used as a backlight for a transmissive image display device, but is not particularly limited to such use. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing an embodiment of a transmissive image display device according to the present invention. Fig. 32-201033644 Fig. 2 is a view showing an embodiment of a light diffusing plate according to the present invention. Sectional view. Fig. 3 is a cross-sectional view showing another embodiment of the light diffusing plate of the present invention. Fig. 4 is an explanatory view showing a method of measuring the light transmittance of light having a wavelength of 6 〇〇 nm in an optical path length of 200 mm. ® [Main component symbol description] 1 : Surface light source device 2 : Light source 3 : Light diffusing plate 20 : Transmissive image display panel 30 : Transmissive image display device (liquid crystal display device ) ❹ -33-