201038978 六、發明說明： 【發明所屬之技術領域】 本發明係關於光擴散薄膜、其積層片及其製造方法。 詳細而言，係關於一種光的透過度和擴散度二種特性均優 異之光擴散薄膜，例如用於採用LED光源的照明裝置時， 除了使直進性強的LED光源之光擴散成大面積，且不看見 強光的光源點之外，更進一步，藉由已抑制其光線的透過 率度的降低度之少數LED光源，使廣面積呈現均勻的光量 〇 分布’且可達高的照度和亮度之光擴散薄膜、其積層片及 其製法。 【先前技術】 近年’ LED(發光二極管）因具有消耗能量少且使用壽命 長等特徵，從省能量之觀點而備受注目，廣泛用於室內照 明、車內照明、外燈、廣告燈及顯示裝置等之照明用光源。 惟，由L E D光源所發出的光，因直進性（指向性）高，於點 狀的狹窄範圍之照明’可有效地照明，而使用於上述般大 Ο 面積照明時’需使用大量的光源，無法有效地運用省能源 之特點，且不易具均勻的明亮度係其課題。 爲於廣面積具有均勻光量分布，必須進行各種計策。 例如具備至少一個的一次光源和板狀導光體，此導光 體係引導發自一次光源的光’且具有發自上述一次光源的 光所射入之光射入面及被引導的光所射出之光射出面，上 述導光體係於上述光射出面及其相對側的裏面之二者或一 者’具備光射出機制’且於上述光射出面及上述裏面之二 201038978 者或一者，具備至少一個的局部透鏡列形成部位，各個的 局部透鏡列形成部位，含有至少一個的局部透鏡列，此局 部透鏡列係被形成於與發自上述一次光源而射入上述光射 入端面的光中，最大強度光的射入位置的亮度分布之波峰 光的方向相異之方向，依此而揭示解決亮度不均勻之方法 (參考專利文獻1)。 又揭示一種於一端形成開口部位，其內側壁具備含有 光反射面的光源接收部位之燈罩.，和裝設於光源接收部位 〇 之發光二極管，以及裝設於開口部位前面之顯示板，將來 自發光二極管的光擴散反射且使之均勻之技術（參考專利 文獻2)。 更揭示一種面照明光源，其係具備放射光之光源、傳 送此光源的光且在其放射方向的規定位置具有放射面之光 學性透明導光體、封閉此導光體的上述放射面以外的面之 無蓋盒、以及裝設於此盒與上述導光體間的全部之內側反 射手法、和裝設於上述放射面且將來自上述光源的光，以 〇 固定比例反射之放射側反射手法（參考專利文獻3)。 上述專利文獻1〜3所揭示的方法，有光源的結構複雜 且經濟性不佳等課題。雖可因應面狀的照明，惟不易因應 例如螢光燈般之管狀照明體。 另一方面，以螢光燈爲光源之照明裝置，達到均勻的 光量分布之方法，係揭示一種使用由各種方法製得的光擴 散薄膜之方法。 例如將由微粒等形成的擴散性物質與黏合劑樹脂之混 '201038978 合物塗布而積層之方法（參考專利文獻4)、將非相溶的熱塑 性樹脂熔融擠壓而製膜之方法（參考專利文獻5、專利文獻 7等）以及於薄膜表面進行壓紋加工等賦形處理而控制表面 形狀之方法（參考專利文獻6)等。 惟，先前既知的光擴散薄膜，若使用於採用LED光源 之照明裝置時，其擴散性不佳，且無法達到充分符合市場 需求之水準。特別是，因LED光源具有強的光的指向性， 故光源點不會消失且光源周邊的光量升高（以下稱爲點消 〇 失性）。爲抑制此現象，而面臨全光線透過率降低，且照明 裝置整體的光量（以下稱爲全光量）降低之課題。 本發明者等，致力硏究於解決上述二律背反之方法發 現，降低平行光線透過率，可有效地提高點消失性，而提 高全光線透過率，可有效地提高整體之光量。 例如專利文獻5的比較例中，揭示平形光線透過率低 之例，因全光線透過率低而全光量亦低。另一方面，專利 文獻6的實例中，雖揭示一已改善全光線透過率之例，惟 ^ 因平行光線透過率升高，而點消失性不佳。 又，專利文獻7中記載全光線透過率及擴散透過率， 若透過此數値來求平行光線透過率，實例1及實例2分別 爲4.6及2· 1 % ’與專利文獻4的實例相同，平行光線透過 率高且點消失性差。 另一方面，液晶顯示裝置（LCD)因薄且輕量、低消費電 力等特徵而廣泛應用於平面板顯示器，其用途例如行動電 話、個人數位秘書（PDA) '個人電腦、電視等資訊用顯示元 201038978 件，且逐年漸增。 在液晶顯示裝置中，爲抑制從光源至面板的光傳送過 程之耗損’並提高面板上的亮度，故於液晶層的下側裝設 逆光組件。其中’從背面照射液晶層使其發光者相當普及， 惟從光源的配置方式可分類爲旁側型和即下型。 近年，逆光組件不僅使用於液晶顯示裝置，更使用於 燈具或電子看板等廣泛領域。 此逆光組件，係組合逆光和透鏡薄膜、光擴散薄膜及 Ο 亮度提升薄膜等各種的光學薄膜和擴散板等光學零件，爲 提高面板上的亮度及亮度的一致性。通常使用2~4片的零 件（參考非專利文獻1)。 例如，揭示一種爲提高亮度之透鏡薄膜（參考專利文獻 8) ° 此方法係利用透鏡的集光效果來提高亮度，故可提高 從正面觀看時之亮度，從斜角觀看時之亮度較從正面觀看 時之亮度，大幅地下降。且爲高價品。 〇 爲解決上述從斜角觀看時之亮度較從正面觀看時之亮 度大幅下降之方法，係除透鏡薄膜以外，更倂用2片的異 向性光擴散薄膜之技術（參考專利文獻9)。 一片的上述透鏡薄膜，其亮度的一致性不佳，而揭示 一種組合此透鏡薄膜和異向性的光擴散薄膜之技術（參考 專利文獻10)。 又，提議一種於上述透鏡薄膜，倂用亮度更提升的薄 膜之方法（參考專利文獻11)，惟對於降低亮度的角度依賴 201038978 性無助益。 近年，藉由提高逆光裝置的性能而具有高亮度，以及 大型電視或汽車導航用途中，亮度的角度依賴性之改善較 正面亮度的提高更被強烈需求。 又’強烈需求從減少零件來降低耗損和成本，以及裝 置的薄型化等。 在此’亦探討使單一基材薄膜具有光擴散性之試驗（參 考專利文獻12)。 Ο 惟’專利文獻12中的薄膜係擴散度小，且內面亮度均 勻性和圖形掩蔽性等不佳。 【先前技術文獻】 [專利文獻1]特開2003- 1 86427號公報 [專利文獻2]特開2003-1 86427號公報 [專利文獻3]特開2008-027886號公報 [專利文獻4]特開200卜166114號公報 [專利文獻5]特開平10-111402號公報 ^ [專利文獻6]特開2007-140447號公報 [專利文獻7]特開平09-80208號公報 [專利文獻8]特開2004-4970號公報 [專利文獻9]特開2008-256797號公報 [專利文獻10]特開2006-251395號公報 [專利文獻11]特開平09-506985號公報 [專利文獻12]特開2007-10798號公報 [非專利文獻] 201038978 [非專利文獻1]內田龍男監修「圖解電子顯示器之全部」 (工業調查會刊）P47~48 【發明内容】 解決發明之課題 本發明之目的係解決上述先前技術中的問題點，係提 供一種光透過度和擴散度二種特性均優異之光擴散薄膜， 例如用於採用led光源的照明裝置時，除了使直進性強的 led光源之光擴散成大面積，且不看見強光的光源點之 〇 外，更進一步’藉由已抑制其光線的透過率度的降低度之 少數led光源，使廣面積呈現均勻的光量分布，且可達高 的照度和亮度之光擴散薄膜及其積層片。 解決課題之手法 本發明係鑑於上述情況而有之發明，可解決上述課題 的光擴散薄膜及其積層片係由下述所構成。 1· 一種光擴散薄膜，其特徵係由至少二種的非相溶性的熱 塑性樹脂之混合物而形成，且同時符合下述（1)至（4)之 ^ 特性： (1) 全光線透過率爲66%以上， (2) 霧度爲96%以上， (3) 平行光線透過率爲2.0%以下， (4) 於發明說明書中的變角光度計，以入射角〇度測定的 透過光之擴散度比（DH/DL)爲2.0以下， (惟，DH及DL係以自動變角光度計測定的透過光的變 角光度曲線的波峰高度之一半高度的角度之寬度（半値 201038978 寬度），將光擴散薄膜的捲曲方向固定於垂直方向及水平 方向而測定，大的半値寬度作爲DH，小的半値寬度作 爲 DL)。 2. 如上述第1項之光擴散薄膜，其中DH係30度以上。 3. 如上述第1或2項之光擴散薄膜，其係依據發明說明書 之方法，將光擴散薄膜的捲曲方向固定於試驗品固定台 的上下方向和平行方向及水平方向而測定，測得的主擴 散方向的光之變曲度爲4~ 100%。 Ο 4.如上述第1至3項中任一項之光擴散薄膜，其中該至少 2種的非相溶的熱塑性樹脂之混合物中，至少1種爲聚 烯烴系樹脂而形成。 5. 如上述第4項之光擴散薄膜，其中該至少2種的非相溶 的熱塑性樹脂之混合物，係2種以上的聚烯烴系樹脂而 形成。 6. 如上述第5項之光擴散薄膜，其中該至少2種的聚烯烴 系樹脂之混合物，係包含環狀聚烯烴系樹脂及聚乙烯系 ^ 樹脂而形成。 7. 如上述第6項之光擴散薄膜，其中該環狀聚烯烴系樹脂 於2 3 0°C所測定的熔融流動率係低於0.1-1 .5，該聚乙烯 系樹脂之熔融流動率係爲5~ 1 00。 8. 如上述第5至7項中任一項之光擴散薄膜，其中該至少 2種的非相溶的熱塑性樹脂之混合物而形成的光擴散薄 膜之至少單面，層積著主要由聚烯烴樹脂所形成之表面 層。 -10- 201038978 9.如上述第8項之光擴散薄膜，其中形成該表面層之聚烯 烴系樹脂’係由含有極性基之聚烯烴樹脂而形成。 10. 如上述第9項之光擴散薄膜，其中含有極性基之聚嫌烴 樹脂，係至少含有羧基。 11. 如上述第1至4項中任一項之光擴散薄膜，其中另—種 的熱塑性樹脂，係氟系樹脂而形成。 12. 如上述第1至4項中任一項之光擴散薄膜，其中另一種 的熱塑性樹脂，係聚酯系樹脂而形成。 〇 13.如上述第12項之光擴散薄膜，其中於一方向，延伸2 倍以上。 14. 如上述第1至13項中任一項之光擴散薄膜，其中至少 單面係進行賦形處理而粗面化。 15. 如上述第1至14項中任一項之光擴散薄膜，其中於該 發明說明書中記載的變角光度計，以入射角0度所測得 的透過光的擴散度比（DH/DL)超過2.0之光擴散薄膜的 至少2片，係以與主擴散方向垂直之方向重疊而形成。 Ο 16.—種光擴散薄膜積層片，其特徵係將如上述第1至15 項中任一項之光擴散薄膜，與厚度爲0.1-5 mm、全光線 ' 透過率爲70~100%之塑膠片層積而成。 17. 如上述第1至15項中任一項之光擴散薄膜，其係使用 LED光源而成之照明裝置。 18. 如上述第16項之光擴散薄膜積層片，其係使用LED光 源而成之照明裝置。 19. 一種使用LED光源之照明裝置，其特徵係將如上述第1 -11- 201038978 至15項中任一項之光擴散薄膜裝設於使用LED光源的 照明裝置之出光部位的外面或內面。 20_—種使用LED光源之照明裝置，其特徵係將如上述第 16項之光擴散薄膜積層片裝設於使用LED光源的照明 裝置之出光部位的外面或內面。 21. —種逆光裝置，其特徵係將如上述第1至15項中任一 項之光擴散薄膜裝設於逆光組件之出射光面上。 22. —種逆光裝置，其特徵係將如上述第16項之光擴散薄 〇 膜積層片裝設於逆光組件之出射光面上。 23. —種如上述第1至15項中任一項之光擴散薄膜之製 法，其特徵係將至少二種的非相溶性的熱塑性樹脂之混 合物熔融擠壓成形。 24. 如上述第22項之光擴散薄膜之製法，其係將於擠壓機 熔融之樹脂從模頭擠壓成片狀，於冷卻輥，以壓輥來壓 接此片，使密合並冷卻固化而製膜。 發明之效果 〇 本發明的光擴散薄膜及其積層片，係光的透過度和擴 散度二種特性均優異之光擴散薄膜，特別是因直進光的透 過率小，例如用於採用LED光源的照明裝置時，除了使直 進性強的LED光源之光擴散成大面積，且不看見強光的光 源點之外，更進一步，因已抑制其光線的透過率度之降低 度，即使每單位面積的LED光源數減少，仍可具有均勻且 高之光量。因此’具有可抑制LED光源的光因直進性高而 引起僅狹窄範圍之點狀’其係即所謂採用L E D光源的照明 -12- 201038978 裝置之缺點，且可維持省能源之LED光源的特徵之優點。 相較於先前已知的光擴散薄膜，因大幅地改善擴散 性，例如使用於以螢光燈爲光源之照明裝置時，即使縮短 螢光燈與光擴散薄膜或與光擴散薄膜積層片之距離，仍具 有高度的光擴散性，因此，具有減少照明裝置的厚度或減 少螢光燈的數目之效果。又，例如使用爲液晶顯示器等顯 示裝置之光擴散薄膜時，可減少顯示面板之厚度，且可減 少一種爲提升亮度而使用的亮度提升薄膜或光擴散薄膜等 〇 光學機能調整用薄膜之數目。 本發明之光擴散薄膜及使用此之積層片，除維持上述 的光學特性之外，例如可提升耐熱性等非光學特性。 因此，可有效地使用於室內照明、內照式電子面板之 照明、影印機之光照射或液晶顯示器等顯示裝置之照明等 各種照明。 又’本發明的光擴散薄膜及使用之積層片，係使用爲 逆光裝置之光學零件時，因僅使用一片，即可附予高亮度、 〇 亮度的角度依賴性之降低、內面亮度均勻性及圖形掩蔽性 等逆光裝置用的光學材料所需具備之光學特性，故可提高 逆光裝置之經濟性。特別是附予一大優點，亦即可不使用 高價的透鏡薄膜，且解決當斜角觀看時所發生的亮度降低 等使用透鏡薄膜之課題。 本發明的逆光裝置，因具有與使用透鏡薄膜的逆光裝 置相近的高度之正面亮度，且降低亮度的角度依賴性即使 用透鏡薄膜的逆光裝置之課題，故具有抑制當使用於大型 -13- 201038978 電視時，因斜角觀看而引起的畫面的明亮度之降低之優點。 由此特點，可有效地使用爲例如汽車導航般，大多從 斜角觀看的顯示器之逆光裝置。 若使用於室內或車內照明用燈具的逆光裝置時，相較 於使用透鏡薄膜的逆光裝置，具有於廣範圍呈一致的照度 之優點。 又，本發明的逆光裝置，因僅使用一片的零件，即可 具備上述所有的特性，故具有高經濟性之優點。 0 因此，本發明的逆光裝置，可有效地使用於液晶顯示 裝置、室內照明、內照式電子面板等》 依據本發明的光擴散薄膜之製法，可符合經濟且安定 地製造具有上述特性的本發明之光擴散薄膜。 【實施方式】 實施發明之形態 (光學特性） 本發明的光擴散薄膜必須同時符合下述特性。 q (1)全光線透過率爲66%以上， (2) 霧度爲96%以上， (3) 平行光線透過率爲2.0%以下， (4) 於發明說明書中的變角光度計，以入射角0度測定的透 過光之擴散度比（DH/DL)爲2.0以下。 (惟，DH及DL係以自動變角光度計測定的透過光的變角光 度曲線的波峰高度之一半高度的角度之寬度（半値寬度）， 將光擴散薄膜的捲曲方向固定於垂直方向及水平方向而測 定，大的半値寬度作爲DH，小的半値寬度作爲DL)。 •14- 201038978 以下，DH的方向亦稱爲主擴散方向。 上述全光線透過率較佳爲68%以上，更佳爲 上。特佳爲80%以上，又更佳爲90%以上。100% 因原理上不超過100%，故100%爲上限。若全光線 低於66%，發自LED光源的光線之透過率降低，而 明時的光量降低且照明裝置的照度和亮度亦降低， 當。 \ 上述霧度較佳爲97%以上，更佳爲98%以上 〇 最佳。因原理上不超過100%，故100%爲上限。若 於96%，光擴散性降低且無法均勻地照明，故不適 了均勻地照明，必須增加LED光源數，較不符合經 上述平行光線透過率較爲1.7%以下，更佳爲 下，尤更佳爲1.2%以下。特佳爲〇~1.〇%。〇%最佳 _上不低於〇%’故〇%爲下限。若平行光線透過 2.0 %，點消失性變差，來自光源的強光的點係清 見，而無法呈均勻的照明，故不適當。 Ο 透過光的擴散度比（DH/DL)(以下簡稱爲擴散度 佳爲1.8以下。尤更佳1.6以下，特宜爲〇.7〜1.3。 擴散度比（DH/DL)超過2.0時，光擴散的異向怕 因光擴散至特定方向’面的光量亦即照度和亮度的 降低，故不適當。 上述擴散度比係依據下述方法來測定而求得。 <透過光的擴散度比之測定方法> 使用自動變角光度計（GP-200:村上色彩硏究所 70%以 最佳。 透過率 用爲照 故不適 。100% 霧度低 當。爲 濟。 1 · 5 % 以 :。因原 率超過 楚地看 比），較 三升高， 均勻性 股份公 -15- 201038978 司製）進行測定。 透過測定模式，以光線入射角：〇°(對於試驗品面，上 下、左右均成直角之角度），受光角度：一90°〜9 0° (赤道線 面上的角度），濾光器：使用ND10,光束光圈：10.5mm(VS-l 3.0)，受光光圈：9.1mm(VS-3 4.0)及變角間隔0.1度之條 件來測定，求出當變更SENSITIVITY或HIGH VOLTON之 設定而使透過光的波峰在曲線圖的40〜90%，所測得的透 過光的變角光度曲線之波峰高度的一半高度之角度的寬度 〇 (半値寬度）。 上述測定係於將光擴散薄膜的捲曲方向固定於垂直方 向及水平方向而進行’求得的較大的半値寬度作爲DH，較 小者作爲DL，求出擴散度比（DH/DL)(參考第1圖）。 當光擴散薄膜的表面粗糙度有差異時，將表面較粗糙 的面固定於受光側而進行上述測定。 又’移動受光器之面係定義爲赤道面。 本發明的光擴散薄膜係同時符合上述特性，可充分地 ® 發揮本發明之效果’且上述DH較佳爲30度以上。更佳爲 35度以上，特佳爲40度以上。若dh低於30度，則光的 擴散性降低’不易呈•均勻的照明，故不適當。爲均勻地照 明，必須增加L E D光源數，較不符合經濟。 (光之變曲度） 本發明的光之變曲度，係以下述之方法進行測定而求 得。 <光的變曲度之測定方法> -16- 201038978 使用自動變角光度計（GP-200 :村上色彩硏究所股份公 司製）進行測定。 透過測定模式，以光線入射角：0。（對於試驗品面，上 下、左右均成直角之角度），受光角度：一90°~90°(赤道線 面上的角度），濾光器：使用ND10,光束光圈：l〇.5mm(VS-l 3·〇)，受光光圏：9.1mm(VS-3 4.0)及變角間隔0.1度之條 件來測定，求出當變更SENSITIVITY或HIGH VOLTON之 設定而使透過光的波峰在曲線圖的40〜90%，所測得的透 Ο 過光的波峰之高度（H0)，以及將光線入射角變更爲60°(赤 道線面上的角度）以外，以和上述條件相同條件進行測定時 的透過光的波峰的角度0度時之高度（H60)。使用以此方法 求得的H60和H0，以下述通式算出變曲度。 光的變曲度=H60/ Η〇χ 1 00(% ) (1) 參考第2圖。 移動受光器之面係定義爲赤道面。 該光的變曲度係於主擴散方向進行測定而求得。 Ο 當逆光裝置用光擴散薄膜的表面粗糙度有差異時，固 定在與實際使用於逆光裝置時相同方向使光通過之方向， 而進行上述測定。 上述光的變曲度較佳爲6〜100%，更佳爲8〜100%。 若光的變曲度低於4%，無法充分地發揮上述本發明 的效果，故不適當。 此特性係例如當光照入逆光裝置用光擴散薄膜時，薄 膜中的光的變曲效果之程度，亦即表示以高角度照入的光 -17- .201038978 係向著正面而射出的程度之尺度。亦可爲表示集光效果之 尺度。本發明的光擴散薄膜，具有較先前既知的光擴散薄 膜或透鏡薄膜更大之變曲效果。因此，可有效地發揮本發 明之效果。 例如使用於液晶顯示器用的逆光裝置時，雖然分別使 用一片的先前既知的透鏡薄膜、光擴散薄膜（片）及光擴散 板之零件，亦可符合任一項的上述特性，惟使其具有可同 時符合全部的特性之理想特性者，係本發明之創始。 Ο 雖可附予此理想的特性之原因尙不明，惟推論係同時 符合上述多數的光學而達成。例如光的變曲度高對於亮度 之角度依賴性，以及擴散度高對於內面亮度均勻性或圖形 掩蔽性之貢獻均大。 (光擴散薄膜表面之'表面粗糙度） 本發明的光擴散薄膜，較佳爲至少單面的表面之表面 粗糙度係同向。亦即，測定光擴散薄膜的捲曲方向和與此 方向垂直的方向之平均表面粗糙度，測得的各個的平均表 ^ 面粗糙度RaV和尺&11之比，即表面粗糙度比（1^乂/1^15)較 佳爲0.83〜1.20。若不在此範圍內，例如光擴散的異向性亦 即上述擴散度比（DH/DL)升高，光量亦即照度或亮度之均句 性降低，故不適當。上述表面粗糙度比較佳爲0.91〜1.1。 (光擴散薄膜之構成） 本發明的光擴散薄膜係由至少二種的非相溶性的熱塑 性樹脂之混合物而形成。 上述至少二種的非相溶性的熱塑性樹脂的混合物之存 -18- 201038978 在形態，係連續相及分散相之各個樹脂乃獨立存在亦即海/ 島結構，亦可爲二樹脂形成共連續相之結構。藉由樹脂界 面的光之折射或散射而具有上述特性。 本發明的光擴散薄膜之薄膜厚度，無特別之限制，較 佳爲 10~ 1 000μιη。尤宜 30〜5 00 μιη。 (至少二種的非相溶性的熱塑性樹脂之混合物） 本發明中，使用於至少二種的非相溶性的熱塑性樹脂 之混合物之熱塑性樹脂，例如聚乙烯系樹脂、聚丙烯系樹 〇 脂、聚丁烯系樹脂、環狀聚烯烴系樹脂及聚甲基戊烯系樹 脂等聚烯烴系樹脂、聚酯系樹脂、丙烯酸系樹脂、聚苯乙 烯系樹脂、聚碳酸酯系樹脂、氟系樹脂及其共聚物等。 從此類熱塑性樹脂中，選擇至少二種的非相溶性（彼此 不相溶）之熱塑性樹脂即可，惟考量可安定地發揮上述特性 及經濟性，較佳爲至少一種係聚烯烴系樹脂而形成。 二種類的樹脂中，另一種樹脂較佳爲聚烯烴系樹脂、 聚酯系樹脂及氟系樹脂等。考量光學特性以外的需求特性 ^ 或經濟性等，而適當地選擇。 特別是從耐光性和經濟性之觀點，較佳爲二種類均爲 聚烯烴系樹脂。二種類均爲聚烯烴系樹脂時，其組合係無 特別之限制，惟二種類的聚烯烴系樹脂之折射率差，較佳 爲0.003~0.07之範圍。更佳爲0.005〜0.05之範圍，又更佳 0.0 1 ~ 0 · 0 2。使此折射率差在此範圍'內，可更安定地具有上 述光學特性之光擴散薄膜。例如，若折射率差超過0.0 7， 雖有助於使霧度和平行光線透過率在上述範圍內，惟全光 -19- 201038978 線透過率不易達平衡。另一方面，若低於0.003，雖易於達 成全光線透過率，惟不易達到霧度和平行光線透過率之平 衡。 因此’在上述範圍內，可同時符合上述之各種光學特 性。若不在上述範圍內，即使符合上述的混合比和熔融流 動率，亦無法符合全部特性。 符合上述折射率差的2種的聚烯烴系樹脂之種類，無 特別之限制’惟環狀聚烯烴系樹脂和聚乙烯系樹脂之組 〇 合，可符合上述特性且經濟性優異，故較適用。 環狀聚烯烴系樹脂例如降茨嫌或四環十二稀等具有環 狀聚烯烴結構者。 例如（1)依需求將降茨烯系單體的開環（共）聚物加成馬 來酸、環戊二烯而進行聚合物改良後加氫之樹脂、（2)使降 茨烯系單體進行加聚作用之樹脂、（3)降茨烯系單體和乙烯 或α -烯烴等烯烴系單體進行加聚作用之樹脂等。聚合方 法及添加氫方法係可依據一般的法而進行。 π ^ 聚乙烯系樹脂可爲單聚物，亦可爲共聚物。爲共聚物 時，其中50莫耳％以上，較佳爲乙烯成分。 此樹脂的密度和聚合方法等，亦無限制，惟較佳使用 密度爲0.909以下的共聚物。例如丙烯、丁烯、己烯及辛 烯等共聚物。聚合方法可爲芳環烯金屬衍生物催化法及非 芳環稀金屬衍生物催化法中任一種。 特別是從可安定地附予高擴散性之觀點，較佳使用乙 烯和辛烯之嵌段共聚物。此樹脂係可使用例如大武化學公 -20- 201038978 司製的 INFUSE(TM)。 使用爲上述至少二種的非相溶性之熱塑性樹脂的熱塑 性樹脂之熔融流動率，宜加上各個熱塑性樹脂的熔融流動 率之差。藉此，可更安定地附予上述光學特性。 例如上述的二種類係均使用聚烯烴系樹脂時，熔融流 動率較低的熱塑性樹脂，較佳爲於2 3 0 °C測定之熔融流動率 爲0·1~1·5以下。更佳爲0.1〜1.2，特佳0.1~1.0。低於0.1 時，因製膜的安定性降低，故不適當。相反地，若高於1 . 5 〇 以上，因上述表面粗糙度比或光擴散度比升高，且光擴散 的異向性升高等光學特性惡化，故不適當。 另一方面，熔融流動率高的熱塑性樹脂，較佳爲於 230 °C測定之熔融流動率爲5~100。更佳爲1〇〜1〇〇，特佳 15〜100。若低於5，因光擴散的異向性升高等光學特性惡 化，故不適當。相反地，若超過100時，因製膜的安定性 降低，故不適當。 至少二種的非相溶性的熱塑性樹脂之混合物，係使用 ^ 上述環狀聚烯烴系樹脂和聚乙烯系樹脂之混合物時，上述 熔融流動率低的樹脂，宜使用環狀聚烯烴系樹脂，而另一 方的熔融流動率高之樹脂，宜使用聚乙烯系樹脂。 上述至少二種的非相溶性的熱塑性樹脂之配合比例， 各個質量比較佳爲10/90~90/10，更佳爲20/80~80/20，特 佳爲 30/70〜70/30。 於上述範圍內’可同時符合上述各種的光學特性。若 不在上述範圍內’即使符合下述之內容，亦無法符合全部 -21- 201038978 特性或一部分之特性。 上述樹脂係可選自一般市售的泛用性高之樹脂，爲因 應可更安定地生產等，亦可使用特別製品。 (聚烯烴樹脂形成層之積層） 本發明中’上述至少二種的非相溶性的熱塑性樹脂之 混合物，二種類均使用聚烯烴系樹脂時，理想的實施樣態 係至少二種的聚烯烴系樹脂的混合物所形成之層的至少單 面，係主要層積聚烯烴系樹脂而成的表面層而形成。以下， Ο 將至少二種的聚烯烴系樹脂的混合物所形成之層，簡稱爲 光擴散層。 當熔融擠壓製膜時，發生於擠壓模的出口，例如稱爲 「眼垢」的發生於擠壓模的出口之樹脂劣化物而來的附著 物之現象，因可藉由上述表面層之形成而被抑制，故可長 時間且安定地連續製膜較適當。又，因可抑制當使用乙烯 和辛烯之嵌段共聚物等柔軟性聚烯烴系樹脂時所發生的光 擴散薄膜之遮蔽性，故較適當。 〇 使用於上述表層的形成之聚烯烴系樹脂，因可發揮抑 制遮蔽性之效果，宜使用結晶性之樹脂。 使用於上述表層的形成之聚烯烴系樹脂，係使用含有 極性基之聚烯烴樹脂，乃理想的實施樣態。因此作法可提 升光擴散薄膜與其他材料之黏合性，故較適當。例如在後 述的光擴散薄膜積層片之製造，因可提升與塑膠片之黏合 性，故較適當。又，廣泛使用爲光學用的材料，因可附予 與丙烯酸系樹脂或聚碳酸酯系樹脂之熱黏合性而較適用。 -22- 201038978 上述含有極性基之聚烯烴樹脂，其骨架較佳爲含有乙 烯、丙烯、丁烯、己烯、辛烯、甲基戊烯及環狀烯烴中的 至少一種之單體。 可爲使用一種類的上述單體之均聚物，亦可爲使用二 種以上的單體之共聚物。 本發明的上述含有極性基之聚烯烴樹脂，較佳爲含有 至少一種類的極性基。極性基例如羧酸基、磺酸基、膦酸 基、羥基、縮水甘油基、異氰酸酯基、胺基、醯亞胺基、 Ο 噁唑啉、酯基、醚基、羧酸金屬鹽基、磺酸金屬鹽基、膦 酸金屬鹽基、3級胺鹽基、4級胺鹽基等。可含有一種或二 種以上之此極性基。 可依據構成光擴散層的聚烯烴系樹脂之組成或密合對 象的零件之種類或所需之密合力等，適當地選擇即可，而 至少含有羧基係理想的實施樣態。 本發明中含有極性基的聚烯烴樹脂，極性基可直接導 入聚稀烴樹脂的高分子鏈中，亦可導入其他樹脂，而呈添 ^ 加、混合之狀態。依狀況，本發明的聚烯烴樹脂係於導入 分子鏈的末端或內部之例如羧酸基或羥基，使可與此類基 反應的化合物進行反應而改良，亦可使用。 本發明中，含有上述極性基的聚烯烴樹脂，係可使用 單獨一種’亦可使用配合二種以上之配合組成物。又可爲 不含極性基的聚烯烴樹脂或配合其他種類的樹脂之配合組 成物。爲配合組成物時，含有上述極性基的聚烯烴樹脂， 較佳以10質量％以上而含有。更佳爲30質量％以上。 -23- 201038978 € w ±述@性基的聚烯烴樹脂，較佳由結晶性之樹脂 而形成。較佳使用熔點爲1〇〇~18〇。(：者。 含有i:述極性基的聚烯烴樹脂，係具有上述特性者即 可’無特別之限制，例如可適當地使用市售的樹脂作爲黏 合性聚烯烴樹脂。例如阿杜曼樹脂（TM、三井化學公司製）、 毛德克樹脂（TM、三菱化學公司製）或阿杜德克斯樹脂 (TM、日本聚乙烯公司製）及蒙特法斯托樹脂（TM、住友化 學公司製）’惟不受限於此。 · 〇 藉由將由含有極性基的聚烯烴樹脂而形成之層，積層 於上述光擴散層，較只有光擴散層的單層而成之光擴散薄 膜，可更提升與其他材料之黏合性。改善薄膜的耐阻塞性 或滑動性’且改善光擴散薄膜的操作性等。亦可提供與各 種材料之熱黏合性。 (藉由賦形處理之粗面化） 本發明的光擴散薄膜，以上述方法製得的薄膜之至少 單面，宜藉由賦形處理而粗面化。 ^ 此粗面化處理係於以上述方法製得的光擴散薄膜之表 面，形成凹凸而粗面化即可，無特別之限制，亦可進行消 光加工或壓紋加工等。粗面化處理係使光擴散薄膜通過於 例如已形成凹凸（格子狀的凹凸、無規則狀的凹凸等）之輥 間，於已形成凹凸部位之輥，擠壓片狀材料而進行。 藉由上述粗面化處理而形成的表面凹凸之形成或深度 等，無特別之限制，惟，被賦形的表面凹凸宜爲不配向於 特定方向的無規則的方向性之形狀。亦即，通常採用消光 -24- 201038978 加工或梨地加工之加工方法即可。亦可採用將特殊的表面 凹凸賦形之粗面化方法。 上述粗面化處理，可爲進行於薄膜的製膜步驟之線上 處理方法，亦可爲進行於其他步驟之線外處理方法。 亦可將後述的光擴散薄膜積層片賦形而粗面化。 藉由上述賦形處理之粗面化，可改善薄膜的耐阻塞性 和滑動性，亦改善光擴散薄膜之操作性。且可提升光之擴 散度。可降低擴散度比，亦可降低光的擴散性之異向性。 Ο 本發明的光擴散薄膜之薄膜厚度，無特別之限制，較 佳爲 10~1000μπι。更佳 30~500μιη。 本發明的光擴散薄膜，係可使用一片，亦可重疊二片 以上而使用。重疊二片以上而使用時，可只重疊而使用， 亦可以黏合劑或膠黏劑黏貼而使用。 本發明亦包括一種樣態，係重疊二片以上而使用時， 每片薄膜係使用不符合上述本發明的特性之光擴散薄膜， 藉由重疊而符合上述本發明之特性。例如異向性高的數種 〇 薄膜，以主擴散方向成垂直之方向進行重叠而降低擴散度 比，且符合其他光學特性之方法，係一理想的實施樣態。 藉由此方法，可廣泛爲地抑制異向性之程度，係一種 理想之實施樣態。 本發明的光擴散薄膜，亦可與具有其他特性之光擴散 薄膜或透鏡薄膜等其他工學薄膜進行重疊而使用。採用此 種使用方法時’可只重疊而使用，亦可以黏合劑或膠黏劑 黏貼而使用。 -25- 201038978 (光擴散薄膜之製法） 本發明的光擴散薄膜之製法，只要符合上述光學特性 即可，無特別之限制，從經濟性之觀點，宜爲以熔融擠壓 成形來製膜之方法。 本發明中，爲附予光擴散性，因不需含有非熔融性微 粒，即使以熔融擠壓成形法來進行，亦可降低製膜步驟的 熔融樹脂的過濾薄膜之阻塞，具有生產性優異且製得的薄 膜之澄清度高等特點。 Ο 依據上述熔融擠壓成形法之製膜方法，無特別之限 制，例如T模頭法及吹塑法中之任一種。可爲未延伸之薄 膜，亦可進行延伸處理。 本發明的理想樣態係於擠壓機，將熔融的樹脂從模頭 擠壓成片狀，於冷卻輥，以壓輥來壓接此片，使密合並冷 卻固化而製膜。 只要符合在冷卻輥以壓輥來壓接此片而使密合即可， 其內容無特別之限制。例如亦可以比一般使用的冷卻輥更 Ο 小徑之壓輥來壓接，亦可將片擠出於徑相同的2個冷卻輥 之間，而以此2個冷卻輥進行壓接。 此方法中，亦可使用擠壓輥及/或冷卻輥表面已進行粗 面化處理之輥，同時進行上述賦形處理之粗面化。 藉由上述之處理，可提升光擴散薄膜的光擴散特性之 同向性。 本發明的光擴散薄膜的特性之一，必須於全方向同向 地光擴散。亦即，因係同向性之光擴散薄膜，不受以無延 •26- 201038978 伸地製造爲佳之限制。例如於光擴散層使用聚酯系 時，宜進行一軸延伸。藉由上述之處理，島相係被拉 延伸方向而成細長結構，顯著地提升與此島相的配向 成垂直的方向之光擴散性，可確保本發明的目標之高 性。惟，以此方法所得之光擴散薄膜，大多異向性提 且擴散度比超過本發明之範圍。因此，理想之實施樣 如上述般，將二片以上的薄膜重疊成主擴散方向成垂 而使用。 Ο 本發明的光擴散薄膜可爲單層，亦可爲2層以上 層結構。爲多層結構時，若至少一層係由上述構成而 光擴散薄膜所形成之層，則其他層亦可爲不具光擴散 簡單的透明層。又，亦可爲全層係光擴散層之構成。 爲上述多層結構時，可以多層共擠壓法來製造， 以擠壓層壓法或乾式層壓法來進行。 上述至少二種的非相溶性的熱塑性樹脂之混合物 於製膜步驟的擠壓機等，將各個熱塑性樹脂摻合，亦 ^ 先以捏合法等，於事前作成混合物之形式而使用。 (作用機制） 本發明必須同時符合上述的全光線透過率、平行 透過率、霧度、擴散度及擴散度比等多數之光學特性 於同時符合多數特性，首先係達成先前既知的光擴散 所無法達成的高度之特性。藉此，可製得適用於L E D 用的照明裝置或逆光裝置用等的高機能之光擴散薄膜 上述特性分別包括表示二律背反的舉動之特性。 樹脂 伸於 方向 擴散 高， 態係 直般 之多 成的 性之 亦可 ，可 可預 光線 。關 薄膜 光源 〇 例如 -27- 201038978 全光線透過率和其他特性係表示二律背反舉動。另一方 面，平行光線透過率、霧度及擴散度，以巨觀而言，表示 比例性的舉動之特性値，以微觀而言，尙不及成比例之關 係。因此，明確地表示對於各個特性的個別要素之貢獻， 實屬不易，惟使上述非相溶的樹脂之折射率差或熔融流動 率等樹脂特性，或各個樹脂之種類或混合比等，在上述範 圍內，藉此可安定地達成。 上述特性之一的擴散度比，因使用的製造裝置之差異 Ο 而有大的變化，致力硏究之結果，上述熔融製膜方法中， 於擠壓機將熔融的樹脂從模頭擠壓成片狀，於冷卻輥，以 壓輥來壓接此片，使密合並冷卻固化而製膜，藉此可更安 定地製造。 上述擴散度比，係深受在光擴散層的二種的非相溶樹 脂而形成之相結構的影響所支配。例如，若爲海/島結構， 受島形狀之異向度所支配。與此島形狀之異向度成比例， 而提高擴散度比。亦即，降低島形狀之異向度，亦即提高 〇 島形狀之等向性，實屬重要。 採用上述製造方法，雖提高島形狀的等向性之機制尙 不明確，惟其推論如下所述。 以熔融擠壓法擠出的片中的島成分之形狀，因在模頭 內受到分配，配向於擠壓方向之形狀變細。從模頭被擠壓 出後，於熔融狀態將片傾斜，且島形狀在擠壓方向變細， 因在此狀態下被冷卻固化，一般，因以細長地配向於擠壓 方向之形狀爲形狀而被固定化，故光擴散薄膜的擴散度比 -28 - 201038978 '升高。 惟，依據上述製造方法，於冷卻輥，以壓輥來壓 此壓接部位的入口處之片，係未固化狀態，故於壓 的入口處，形成一種貯液區（亦稱爲貯料器），使未 態的樹脂滯留於此區，於擠壓方向變細的島成分， 面張力，使回復至原本形狀的同向液滴之力作用， 異向度，變形成更同向性的形狀，因該變形的形狀 固化，故島形狀的同向性提高，其結果，光擴散度 Ο 同向性，擴散度比被安定化於上述範圍。 (光擴散薄膜積層片） 本發明的另一發明，係將由上述方法所製得的 薄膜與厚度爲0.1〜5mm且全光線透過率爲70〜100% 片層積而成之光異向擴散性薄膜積層片。 由上述方法所製得的光擴散薄膜，具有上述優 學特性，且可經濟地製得，惟在某些用途，無法符 特性以外之特性，例如耐熱性、耐熱尺寸安定性、 〇 機械特性或阻燃性等特性。藉由將透明的塑膠片與 的光擴散薄膜進行層積，可補足光學特性以外之特 符合市場要求之總合特性。 使用於本發明之透明塑膠片，能符合上述厚度 線透過率的特性即可，不限制樹脂的種類或層構成 使用於本發明的透明塑膠片之厚度，尤宜0.5~ 若薄於0.1 mm，增強效果或補足效果不佳。若超過 上，不利於經濟性且破壞柔軟性。 接時， 接部位 固化狀 係因表 而緩和 被冷卻 亦增加 光擴散 的塑膠 異的光 合光學 剛性等 本發明 性，可 和全光 等。 ，3 m m。 5mm以 -29- 201038978 使用於本發明的透明塑膠片之全光線透過率，較佳爲 80~100%。更佳85〜100% »若低於70%，無法有效地發揮 上述光擴散薄膜之特性。儘量使用全光線透過率高且爲非 擴散性者爲宜。又，亦可使用具擴散性者作爲此塑膠片而 發揮積層效果。 使用於此塑膠片之樹脂，無特別之限制，較佳使用例 如聚酯系樹脂、丙烯酸系樹脂、苯乙烯系樹脂、環狀聚烯 烴系樹脂及聚碳酸酯樹脂等用於光學用途之樹脂。 〇 上述光擴散薄膜積層片之製法，無特別之限制。例如 將光擴散薄膜與塑膠片黏貼之方法。 使用膠黏劑或黏合劑等而黏貼時，具體而言，膠黏劑 例如橡膠系膠黏劑、丙烯酸系膠黏劑、矽系膠黏劑、乙烯 系膠黏劑等。因本發明的光擴散薄膜積層片可能使用於高 溫，故較佳爲於常溫~120°c仍安定之膠黏劑。其中的丙烯 酸系膠黏劑，因低價而被廣泛使用。無論使用何種膠黏劑， 其厚度較佳爲〇.5~50μιη。 〇 黏合劑例如藉由熱或催化劑之助力而黏合之黏合劑。 具體而言，可使用例如矽系黏合劑、聚胺甲酸酯系黏合劑、 聚酯系黏合劑、環氧系黏合劑、氰丙烯酸酯系黏合劑、丙 烯酸酯系黏合劑等。因本發明的光擴散薄膜積層片可能使 用於高溫，故宜爲於常溫〜120 °c仍安定之黏合劑。其中， 環氧系黏合劑因強度、耐熱性優異，可適當地使用。氰丙 烯酸酯系黏合劑’因即效性和強度優異，故可使用於有效 率的積層片之製作。聚酯系黏合劑，因強度和加工性優異， -30- 201038978 故特別適用於積層片之製作。此類黏合劑，依據黏合方法 係分類爲熱硬化型、熱熔型、二液混合型等，宜使用可連 續生產的熱硬化型或熱熔型。無論使用何種黏合劑，其厚 度宜爲0.5〜50μιη。 以膠黏劑或黏合劑將上述塑膠片與光擴散薄膜黏貼之 方法，以使用層壓機之輥至輥或輥至片處理等來黏貼，製 得輥形狀或薄片形狀之製品。例如使用黏合劑時，於塑膠 片或光擴散薄膜中任一者塗布黏合劑，乾燥後與對象材 〇 料，以滾筒進行層壓而積層。 黏合劑的塗層方法，係依據基材或黏合劑的種類而有 多種方法，惟常被使用的有照相凹版塗料器方式、標準塗 料器方式及逆塗料器方式。照相凹版塗料器方式係將部分 含浸黏合劑之照相凹版輥滾動，使由背撐輥輸送的薄膜與 已黏附黏合劑的照相凹版輥接觸，藉以進行塗層。塗層量 係可藉由控制輥的滾動數、黏合劑的黏度等而調整。逆塗 料器方式雖類似於照相凹版塗料器方式，惟利用與其連接 〇 而裝設之儀表來調整黏附於塗層輥的黏合劑之量。 進行上述黏貼時，可依需求而加溫。又，爲具有必要 的黏合強度，可於層壓後進行熱處理。 以膠黏劑黏貼時，亦可使用雙面膠黏片。採用此法時， 宜使用光學的高透明類型之膠黏劑，無特別之限制。例如 亦可使用具有光擴散性之膠黏片。使用此膠黏片時，亦可 使膠黏層具有光擴散性。 本發明，亦可採用使上述光擴散薄膜的製造與上述光 -31 - 201038978 擴散薄膜積層片的製造成整體化之方法來進行。 亦即，亦可於上述透明的塑膠片表面，將構成上述光 擴散薄膜的熱塑性樹脂配合物熔融並擠壓而直接層壓，即 所謂擠壓來製造。亦可於此熔融擠壓層壓法之步驟內，同 時進行上述粗面化處理。 以此擠壓層壓法而進行時，爲提升光擴散薄膜與透明 塑膠片之黏合性或黏合耐久性，宜採取使用已經過增黏塗 層處理、易黏合處理之透明塑膠片等之手法。 Ο 本發明的光擴散薄膜或光擴散薄膜積層片，因具有上 述般優異的光學特性，宜使用爲採用LED光源的照明裝置 之光擴散薄膜。惟無特別之限制，例如亦可有效地使用於 採用螢光燈等LED光源以外的光源之照明裝置。例如，使 用於螢光燈光源的照明裝置時，即使拉近螢光燈與光擴散 薄膜或光擴散薄膜積層片之距離，仍具有高度的光擴散 性，因此，具有減少照明裝置之厚度和降低螢光燈數目等 效果。 Ο 本發明的光擴散薄膜或光擴散薄膜積層片，相較於先 前既知的光擴散薄膜，因大幅地改善其擴散性，當使用於 以螢光燈爲光源的LCD之亮度提升時，可降低光擴散薄膜 等光學機能調整用薄膜之片數。 (使用LED光源之照明裝置） 本發明的另一發明，係將上述的光擴散薄膜及上述的 光擴散薄膜積層片裝置於使用LED光源的照明裝置的出光 部位之外面或內面，而形成使用led光源之照明裝置。 -32- 201038978 先前既知的光擴散薄膜，通常裝置於導光板的出光部 位之外面或內面而使用。本發明的光擴散薄膜和其積層 片，若盡量離開LED光源而使用，則提升上述光擴散性和 點消失性之性能。因此，宜組入上述方法中使用LED光源 之照明裝置而使用。 光擴散薄膜和其積層片之裝置方法，無特別之限制。 例如以膠黏劑或黏合劑黏貼於出光部位的外板之外面或內 面，亦僅蓋上而裝置。若採用黏貼時，可整體使用膠黏劑 〇 或黏合劑而固定，亦可一部分地使用而固定。螢光燈般的 管狀照明裝置時，亦可將光擴散薄膜或其積層片，以沿著 此外管的內側之形式，插入其外管的內面而裝設。 亦可無外板，僅裝置本發明的光擴散薄膜或其積層片。 (用爲逆光裝置用之使用方法） 本發明的光擴散薄膜或光擴散薄膜積層片，因具有上 述般優異之光學特性，可適用爲提升逆光裝置的亮度或照 度之零件。 ® 將上述本發明的光擴散薄膜或光擴散薄膜積層片裝設 於逆光組件之出光面上而成，實爲重要之事。此時，光擴 散薄膜或光擴散薄膜積層片之裝設方法，無特別之限定。 可僅重疊而裝設，亦可以膠黏劑或黏合劑來固定。亦可以 雙面膠帶來固定。 又’亦可裝設於設在逆光裝置的上面之液晶面板之最 下面。 藉由此措施，可發揮上述本發明之效果。 -33- 201038978 (逆光組件）. 使用本發明的光擴散薄膜或光擴散薄膜積層片之逆光 組件，係於至少單面具有射出光面之組件即可，其結構等 不受任何之限制。可爲側光方式或即下方式。若爲側光方 式，其導光板之結構亦不受限制。 使用於逆光組件的反射薄膜或反射板之種類，亦不受 限制。可爲白色反射類型、金屬反射類型及其他類型中之 任一者。 Ο 使用於逆光組件之光源，亦不受限制。可爲例如電燈 泡、發光二極管（LED)、電致發光面板（EL)、冷陰極管（CCFL) 及熱陰極管（HCFL)中之任一者，亦可爲其組合者或其他光 源。 本發明的光擴散薄膜或光擴散薄膜積層片，因爲即使 僅使用一片此類零件，即可提供高亮度、降低亮度的角度 依賴性、內面亮度均勻性及圖形掩蔽性等逆光裝置所必需 具備之光學特性，故使用一片實屬重要，惟可倂用二片以 Ο 上，亦可與先前已知的透鏡薄膜或光擴散薄膜等併用。尙 可倂用其他光擴散片或光擴散板。此時，亦可倂用多數種 類的光學零件。宜依據市場需求的特性或經濟性等，適當 地選擇而使用。 實例 以下，舉實例以更具體地說明本發明，惟本發明不受 限於下述實例，在符合本發明的意旨之範圍內，可加以適 當的變更而實施，諸如此類皆包含於本發明之技術範圍。 -34- 201038978 實例中採用的測定‘評價方法，係如下所述。實例中的「份」 係指「質量份j，「％j係指「質量％」。 <全光線透過率、平行光線透過率及霧度> 使用日本電色工業股份公司製霧度測定器「NDH-2000」，依據JIS K 7136而測定。 該測定係固定於試驗品固定部位使光擴散薄膜的捲曲 方向成垂直方向，使用依此測定所得的測定値。若光擴散 薄膜的表面粗糙度有差異時，將表面較粗糙的面固定於受 〇 光側而測定。例如僅有單面進行粗面化處理之光擴散薄 膜，實際使用時，係於光通過之方向進行而測定。 <透過光之擴散度比> 使用自動變角光度計（GP-200 :村上色彩硏究所股份公 司製）進行測定。 透過測定模式，以光線入射角：〇°(對於試驗品面，上 下、左右均成直角之角度），受光角度：一90°〜90°(赤道線 面上的角度），濾光器：使用ND10,光束光圈：10.5mm(VS-l f) W 3.0)，受光光圈：9.1mm(VS-3 4.0)及變角間隔0.1度之條 件來測定，求出當變更SENSITIVITY或HIGH VOLTON之 設定而使透過光的波峰在曲線圖的4 0〜90%，所測得的透 過光的變角光度曲線之波峰高度的一半高度之角度的寬度 (半値寬度）。 上述測定係於將光擴散薄膜的捲曲方向固定於垂直方 向及水平方向而進行，求得的較大的半値寬度作爲DH，較 小者作爲DL，求出擴散度比（DH/DL)(參考第1圖）。 -35- 201038978 當光擴散薄膜的表面粗糙度有差異時，將表面較粗糙 的面固定於受光側而進行上述測定。 <光之變曲度> 使用自動變角光度計（GP-2 00 :村上色彩硏究所股份公 司製）進行測定。 透過測定模式，以光線入射角：0。（對於試驗品面，上 下、左右均成直角之角度），受光角度：一90。〜90。（赤道線 面上的角度），濾光器：使用ND10,光束光圈：10.5mm(VS-l 〇 3.0)，受光光圈：9.1 mm (VS-3 4.0)及變角間隔0.1度之條 件來測定，求出當變更SENSITIVITY或HIGH VOLTON之 設定而使透過光的波峰在曲線圖的4 0〜90%，所測得的透 過光的波峰之高度（H0)，以及將光線入射角變更爲60°(赤 道線面上的角度）以外，以和上述條件相同條件進行測定時 的透過光的波峰的角度0度時之高度（H60)。使用以此方法 求得的H60和H0，以下述通式算出變曲度。 光的變曲度=H60/ ΗΟχ 1 00(% ) (1) ® 參考第2圖。 移動受光器之面係定義爲赤道面。 該光的變曲度係於主擴散方向進行測定而求得。 當光擴散薄膜的表面粗糙度有差異時，固定在與實際 使用時相同方向使光通過之方向，而進行上述測定。 <耐光性> 使用晝光老化試驗器（思佳試驗機器公司製，S3 00) ’ 以試驗品面放射照度：78W/m2、波長範圍：3 00〜400nm、 -36- 201038978 連續照射、有降雨（60分鐘中，有12分鐘降雨）之條件，曝 露於63°C><50%RH之環境400小時，評價其色差變化（△* ab) 〇 <平均表面粗糙度比> 使用小坂硏究所股份公司製的萬能表面形狀測定器 MODEL SE - 3C，以縱向倍率：2000~10000、截止：〇.25mm、 測定長·· 8 m m、測定速虔：〇. 5 m m /分之條件進行測定。 上述測定係表示測定光擴散薄膜的捲曲方向和與此方 〇 向垂直的方向之平均表面粗糙度，所得的各個平均表面粗 糙度即RaV和RaH之比的表面粗糙度比（RaV/RaH)。此測 定係分別進行5次，再使用其平均値。 <熱塑性樹脂之熔融流動率> 依據JIS K 7210 A法，以230°c、2.16kgf之條件進行 測定。一部分樹脂係以實例之條件來測定。 <使用於採用LED光源的照明裝置時的光擴散性之評價> 使用毛萊安斯公司製的40 W晝光色透明燈罩型式的螢 ^ 光燈型led照明燈（MLT-40KC)，將光擴散薄膜或光擴散薄 膜積層片黏貼於此透明燈罩表面，於正上方5cm處，以數 位相機（KONICA MINOLTA製，蒂瑪重A700，拍攝條件·· 手動模式，快門速度1 / 1 000秒，光圈値6.3)拍攝照明燈部 位之相片，以下述基準來進行各性能評價。 (1)明亮度 以實例1的光擴散薄膜之明亮度爲基準，較此明亮度 更明亮者表示爲◎，同程度的明亮度爲〇，明亮度更差者 -37- 201038978 〇 〇 表示爲X。明亮度係以相片的白度來判定。 (2) 點消失性 於上述相片，進行以下之判定。 看不見光源之點者：◎ 稍稍看見光源之點者：〇 清楚看見光源之點者：X (3) 明亮度之擴展 於上述相片，進行以下之判定。 螢光燈型LED照明燈的外管之90%以上係發亮可見 ◎ 螢光燈型LED照明燈的外管之70〜90%係發亮可見 〇 螢光燈型LED照明燈的外管之50~69%係發亮可見 Δ 螢光燈型LED照明燈的外管之50%以下係看不見發亮 X (實例1) 使用池貝鐵工公司製 PCM45擠壓機，於樹脂溫度 250°C，將50質量份的環狀聚稀烴系樹脂（TOPAS(TM)6015 Topas Advanced Polymers 公司製 熔融流動率： 0_4 1 (23 0°C ’ 2_16kgf))和50質量份的由乙烯與辛烯形成之 嵌段共聚樹脂（大武•化學公司製INFUSE(TM)D9817.15熔 融流動率：26(23(TC，2.16kgf))熔融混合，以τ模頭擠壓， 以經過梨皮花樣加工之冷卻輥（Ra=〇.55)進行冷卻，製得厚 者 者： 者： 者 -38- 201038978 度4 0 0 μιη之光擴散薄膜。上述冷卻輥的相對面係使用鏡面 之壓輥。 製得的光擴散薄膜之特性係如第1表所示。本實例所 製得之光擴散薄膜，係全部的光學特性均優異，係高品質 的使用LED光源等各種光源的照明裝置用之光擴散薄膜。 由耐光性試驗測得之色差爲1 . 〇，其耐光性亦優異。 (實例2) 使用池貝鐵工公司製PCM45擠壓機，於樹脂溫度 O 250〇c，將35質量份的環狀聚烯烴系樹脂（TOPAS(TM)60 15 Topas Advanced Polymers 公司製 熔融流動率： 0.41(230°C，2.16kgf))和65質量份的由乙烯與辛烯形成之 嵌段共聚樹脂（大武•化學公司製INFUSE(TM)D9817.15 熔融流動率·· 29(230°C，2.16kgf))熔融混合，以T模頭擠 壓，以鏡面之冷卻輥進行冷卻，製得厚度3 00 μιη之光擴散 薄膜。上述冷卻時，使用真空盒來進行薄膜與冷卻輥之密 合。 ® 製得的光擴散薄膜之特性係如第1表所示。 本實例所製得之光擴散薄膜’相較於實例1的光擴散 薄膜，點消失性稍差，惟明亮度更佳，係高品質之光擴散 薄膜。 由耐光性試驗測得之色差爲1.0，其耐光性亦優異。 (實例3) 實例.2之方法中，除薄膜的厚度爲1 5 0 μιη以外，以和 實例2相同之方法而製得光擴散薄膜。 -39- 201038978 製得的光擴散薄膜之特性係如第1表所示。 本實例所製得之光擴散薄膜’相較於實例1的光擴散 薄膜，明亮度之擴展稍差，惟明亮度更佳，係高品質之光 擴散薄膜。 (實例4) 實例2之方法中，除薄膜的厚度爲200 μιη以外，以和 實例2相同之方法而製得光擴散薄膜。 製得的光擴散薄膜之特性係如第1表所示。本實例所 〇 製得之光擴散薄膜，具有和實例3的光擴散薄膜同等之特 性，係高品質之光擴散薄膜。 (實例5) 在實例1之方法中，除光擴散薄膜的厚度爲200μιη以 外，以和實例2相同之方法而製得光擴散薄膜。 製得的光擴散薄膜之特性係如第1表所示。 本實例所製得之光擴散薄膜，相較於實例1的光擴散 薄膜，點消失性和明亮度之擴展稍差，惟明亮度更佳，係 ^ 高品質之光擴散薄膜。 (實例6) 使用池貝鐵工公司製PCM45擠壓機，於樹脂溫度 250°C，將35質量份的環狀聚烯烴系樹脂（TOPAS(TM)6015 Topas Advanced Polymers 公司製，熔融流動率： 0.4 1 (2 3 0 °C，2.1 6kgf))和65質量份的由乙烯與辛烯形成之 無規共聚樹脂（大武•化學公司製ENGAGE(TM)8137熔融 流動率：30(1 90°C，2.16kgf))熔融混合，以T模頭擠壓， -40- 201038978 以鏡面之冷卻輥進行冷卻’製得厚度300μιη之光擴散薄 膜。上述冷卻時，使用真空盒來進行薄膜與冷卻輥之密合。 製得的光擴散薄膜之特性係如第1表所示。本實例所 製得之光擴散薄膜，具有和實例3的光擴散薄膜同等之特 性，係高品質之光擴散薄膜。 (實例7) 於真空乾燥機，以1 8 0 °c進行乾燥3小時，將8 5質量 份的充分去除水分之實際無潤滑劑之聚對苯二甲酸乙二醇 〇 酯樹脂與15質量份的普萊姆聚合物股份公司製的低密度 聚乙烯樹脂（SP1540)之混合物饋入單軸擠壓機，於280°C進 行熔融，通過過濾器、齒輪泵以除去異物，進行擠壓量的 均勻化後，在控溫於25 °C的冷卻轉筒上，由T模頭擠壓成 片狀。此時，使用直徑0.1mm的金屬線狀電極，外加靜電 使密合於冷卻轉筒，製得未延伸薄膜。其次，於長方向以 溫度103°C往長方向延伸5』倍，製得厚度爲ΙΟΟμιη的光擴 散薄膜之原版。製得的光擴散薄膜的原版之擴散度比爲 Ο 2.5。 於主擴散方向爲直交之方向，以光學用黏合劑將2片 光擴散薄膜的原版黏合而製得光擴散薄膜。黏合劑層之厚 度爲1 0 μιη。 製得的光擴散薄膜之特性係如第1表所示。本實例所 製得之光擴散薄膜，係高品質的光擴散薄膜。惟’由耐光 性試驗測得之色差變化爲3.7，相較於實例1或2的光擴散 薄膜，其耐光性稍差。 -41 - 201038978 (實例8) 使用池貝鐵工公司製PCM45擠壓機，於樹脂溫度 250°C，將50質量份的氟系樹脂（Kynar 720(PVDF)阿爾科 瑪公司製熔融流動率：10(230 °C，5kg f))和50質量份的聚 甲基戊烯系樹脂（TPX(TM)DX820三井化學公司製，溶融 流動率：110(260 °C，5kg f))熔融混合，以τ模頭擠壓，以 鏡面之冷卻輥進行冷卻，製得厚度100 μιη的光擴散薄膜之 原版。上述冷卻時，使用真空盒來進行薄膜與冷卻輥之密 Ο 合。又於單面進行電暈處理。製得的光擴散薄膜之原版， 擴散度比爲1 2.7。 於主擴散方向爲直交之方向，以光學用黏合劑將2片 光擴散薄膜的原版黏合而製得光擴散薄膜。黏合劑層之厚 度爲1 0 μιη。 製得的光擴散薄膜之特性係如第1表所示。本實例所 製得之光擴散薄膜，係高品質之光擴散薄膜。 (實例9) 0 使用池貝鐵工公司製 PCM45擠壓機，於樹脂溫度 250°C，將50質量份的氟系樹脂（Kynar 720(PVDF)阿爾科 瑪公司製熔融流動率：10(230 °C，5 kg f))和50質量份的環 狀聚烯烴系樹脂（TOPAS(TM)6013 Topas Advanced Polymers公司製熔融流動率：2 · 1 (2 3 0 °C，2.1 6 k g f))熔融 混合，以T模頭擠壓，以鏡面之冷卻輥進行冷卻’製得厚 度70μιη的光擴散薄膜之原版。上述冷卻時’使用真空盒 來進行薄膜與冷卻輥之密合。又於單面進行電暈處理。製 -42- 201038978 得的光擴散薄膜之原版，擴散度比爲Π·2。 於主擴散方向爲直交之方向，以光學用黏合劑將2片 光擴散薄膜的原版黏合而製得光擴散薄膜。黏合劑層之厚 度爲1 0 μιη » 製得的光擴散薄膜之特性係如第1表所示。本實例所 製得之光擴散薄膜，係高品質之光擴散薄膜。 (比較例1) 使用池貝鐵工公司製 PCM45擠壓機，於樹脂溫度 〇 25 0°c，將35質量份的環狀聚烯烴系樹脂（TOPAS(TM)6013 Topas Advanced Polymers 公司製，熔融流動率：2.0(230 °C， 2.16kgf))和65質量份的由乙烯與辛烯形成之嵌段共聚樹 脂（大武•化學公司製INFUSE(TM)D9817.15 熔融流動 率：26(230°C，2.16kgf))熔融混合，以T模頭擠壓，以鏡 面之冷卻輥進行冷卻，製得厚度400μιη之光擴散薄膜。上 述冷卻時，使用真空盒來進行薄膜與冷卻輥之密合。 製得的光擴散薄膜之特性係如第1表所示。本比較例 ^ 所製得之光擴散薄膜，相較於實例1的光擴散薄膜，雖明 亮度更佳，惟光擴散的異向性較高且明亮度的擴展較差’ 從具有均勻的光量之觀點，係劣質之光擴散薄膜。 (比較例2) 使用塗布機，將50質量份的平均粒徑爲3 μιη的圓球 狀之丙烯酸樹脂顆粒（東洋紡績公司製，塔伏奇古 (TM)FH-S3 00)和50質量份的聚胺甲酸酯樹脂之混合物’塗 布於厚度爲250μιη的高透明性聚酯薄膜（東洋紡績公司製 -43- 201038978 科斯摩夏因A4 3 00)之單面並進行乾燥，使乾燥後的厚度爲 25 μπι，而製得光擴散薄膜。 製得的光擴散薄膜之特性係如第1表所示。本比較例 所製得之光擴散薄膜，相較於實例1的光擴散薄膜，雖明 亮度更佳，惟點消失性和明亮度的擴展較差，係低品質之 光擴散薄膜。 (比較例3) 使用塗布機，將不與黏合劑樹脂混合且厚度爲奈米程 Ο 度的極薄片狀之二氧化矽顆粒（AGC耶思艾德克公司製珊 普拉利（TM)LFSHN050)，塗布於厚度爲2 5 0 μπι的高透明性 聚酯薄膜（東洋紡績公司製，科斯摩夏因Α4 3 00)之單面並 進行乾燥，使乾燥後的厚度爲30 μιη，而製得光擴散薄膜。 製得的光擴散薄膜之特性係如第1表所示。本比較例 所製得之光擴散薄膜，雖在點消失性和明亮度的擴展，具 有和實例4的光擴散薄膜同等之特性，惟全光線透過率較 低且明亮度較差，係低品質之光擴散薄膜。 Ο (比較例4) 使用池貝鐵工公司製PCM45擠壓機，於樹脂溫度 250°C，將50質量份的環狀聚烯烴系樹脂（TOPAS(TM)6015 T 〇 p a s A d v a n c e d Ρ ο 1 y m e r s 公司製，熔融流動率： 0.41(2301：，2.16kg f))和50質量份的由乙烯與辛烯形成之嵌 段共聚樹脂（大武•化學公司製INFUSE(TM)D9 1 00.05，熔 融流動率：2.1 (230°C，2.16kgf))熔融混合，以T模頭擠壓’ 以鏡面之冷卻輥進行冷卻，製得厚度175μηι之光擴散薄 -44 - 201038978 膜。上述冷卻時’使用真空盒來進行薄膜與冷卻輥之密合。 製得的光擴散薄膜之特性係如第1表所示。本比較例 所製得之光擴散薄膜，具有高的平行光線透過率及高的擴 散度比，點消失性和明亮度的擴展較差，係低品質之光擴 散薄膜。 (比較例5) 使用池貝鐵工公司製PCM45擠壓機，於樹脂溫度 2 5 0°C，將35質量份的環狀聚烯烴系樹脂（T〇PAS(TM)6013 〇 Topas Advanced Polymers 公司製，熔融流動率：2.1(230 °C)) 和65質量份的由乙烯與辛烯形成之嵌段共聚樹脂（大武· 化學公司製INFUSE(TM)D9817.15熔融流動率：26(230t)) 熔融混合，以T模頭擠壓，以鏡面之冷卻輥進行冷卻，製 得厚度175μιη之光擴散薄膜。上述冷卻時，使用真空盒來 進行薄膜與冷卻輥之密合。 製得的光擴散薄膜之特性係如第1表所示。本比較例 所製得之光擴散薄膜，具有高的平行光線透過率及高的擴 〇 w 散度比，點消失性和明亮度的擴展差，係低品質之光擴散 薄膜。 (比較例6) 將一種由表面經過壓紋加工的聚碳酸酯樹脂所形成的 光擴散薄膜進行特性評價。 結果如第1表所示。 本比較例所製得之光擴散薄膜，具有高的平行光線透 過率及高的擴散度比，點消失性和明亮度的擴展差，係低 -45- 201038978 品質之光擴散薄膜。 又’色差變化達9.5之高，耐光性差。 【光擴散薄膜積層片之製造】 (實例10) 將實例1至6所製得的光擴散薄膜與厚度250μιη且全 光線透過率爲92%之高透明聚酯薄膜（東洋紡績公司製，科 斯摩夏因Α43 00)，以光學雙面膠粘片來黏貼，而製成光擴 散薄膜積層片。 ¢) 任—積層片’均具有與各個的光擴散薄膜同等之光學 特性，係高品質之光擴散材料。且製得的光擴散薄膜積層 片，較實例1至6的光擴散薄膜，具有更佳的耐熱性和強 度等非光學特性。 (實例Π) 實例1的方法中’使以聚胺甲酸酯系的增黏塗層劑進 行表面處理之厚度爲2 00 μπι且全光線透過率爲88%的聚碳 酸酯片通過於壓輥側’藉此製得由聚碳酸酯片層積而成之 〇 ^ 光擴散薄膜積層片。 本實例所製得的光擴散薄膜積層片，具有和實例1的 光擴散薄膜同等之光學特性，使用爲採用LED等各種光源 的照明裝置用之光擴散材料時，係高品質。且較實例1的 光擴散薄膜’具有更佳的耐熱性和強度等非光學特性。 (實例12) 使用毛萊安斯公司製的40W白晝光透明燈罩型式的螢 光燈型LED照明燈（MLT-40KC)，以光學用的雙面膠帶，將 -46 - 201038978 實例1的光擴散薄膜及實例8的光擴散薄膜積層片黏貼於 此透明燈罩表面。可呈現一種光線擴展於整體外管且看不 見LED光源的點之螢光燈般的均勻且穩定之照明光線。 (比較例7) 實例12中，換成裝置比較例2的光擴散薄膜時，光擴 散性降低，光無法擴展於外管整體，且清楚地看見LED光 源之點。 (實例13) 〇 使用2台的熔融擠壓機，於第1的擠壓機’以35質量 份的環狀聚烯烴系樹脂（T〇PAS(TM)6013S-04 Topas Advanced Polymers 公司製，熔融流動率：2.0(230°C， 2.16kg f))和65質量份的由乙烯與辛烯形成之嵌段共聚樹 脂（大武•化學公司製 INFUSE(TM)D9817.15 熔融流動 率：26(230 °C，2.16kg f))作爲光擴散層，於第2的擠壓機， 聚丙烯系的黏合性樹脂（阿杜瑪（TM)QF551三井化學公司 製，熔融流動率：5_7(190°C ’ 2_16kgf))爲兩表層（熱密合 Ο 層），以T模頭方式熔融共擠壓後，以鏡面之冷卻輥進行冷 卻，製得總厚度400μιη之兩面係以熱密合層層積而成之光 擴散薄膜。上述冷卻時’薄膜與冷卻輥之密合係以和實例 1相同的方法來進行。即使長時間連續地製膜’亦不發生 眼垢。 製得的光擴散薄膜具有和實例1同等的光學特性’且 熱黏合性優異，藉由熱黏合於基材而提升光擴散薄膜之尺 寸安定性。 -47- 201038978 熱黏合性及尺寸安定性係以下述方法來評價。無論任 一者均爲〇。 <熱黏合性> 將厚度爲3mm的表面平滑且透明之丙烯酸板（三菱麗 陽（股）製：亞克里萊特）裝設於熱壓機的固定台上，於此丙 烯酸板上放置試驗品，更進一步，於其上覆蓋厚度爲 3mm(硬度HsA50°)的矽橡膠片，以表面溫度設定爲180°C 之加壓用壓頭，於上述的矽橡膠片上進行壓制，以49N/cm2 〇 之壓力壓住3 0秒。加熱壓黏後，於溫度23 °C、相對濕度 65%的環境下，放置30分鐘，使用東洋精機公司製「田西 隆」（UTM- III L)，以3 00mm/分的速度180度剝離時之阻 力値即爲密合力。 密合力之判定係以下述之基準來進行。201038978 VI. Description of the Invention: [Technical Field of the Invention] The present invention relates to a light-diffusing film, a laminated sheet thereof, and a method of manufacturing the same. Specifically, it relates to a light-diffusing film excellent in both light transmittance and diffusivity, for example, when used in an illumination device using an LED light source, in addition to diffusing light of a direct-intensity LED light source into a large area, Moreover, in addition to the point of the light source of the glare, the illuminance and brightness of the wide area are uniformly obtained by a small number of LED light sources that have suppressed the decrease in the transmittance of the light. Light diffusing film, laminated sheet thereof and preparation method thereof. [Prior Art] In recent years, LEDs (light-emitting diodes) have attracted attention from the viewpoint of energy saving because of their low energy consumption and long service life. They are widely used in indoor lighting, interior lighting, exterior lights, advertising lights, and displays. A light source for illumination such as a device. However, the light emitted by the LED light source is highly straightforward (directivity), and the illumination in a narrow range of dots can be effectively illuminated, and when used in the above-mentioned large-area illumination, a large number of light sources are used. It is impossible to effectively use the characteristics of energy saving, and it is not easy to have uniform brightness. In order to have a uniform light amount distribution over a wide area, various strategies must be made. For example, it is provided with at least one primary light source and a plate-shaped light guide that guides light emitted from the primary light source and emits light having a light incident from the primary light source and the guided light. a light emitting surface, wherein the light guiding system has either a light emitting mechanism on the light emitting surface and the opposite side of the light emitting surface, and the light emitting surface and the inner surface of the 201038978 or one of At least one partial lens array forming portion, each partial lens column forming portion, comprising at least one partial lens array formed in the light incident from the primary light source and incident on the light incident end surface In the direction in which the direction of the peak light of the luminance distribution of the incident position of the maximum intensity light is different, a method of solving the luminance unevenness is disclosed (refer to Patent Document 1). Further disclosed is a lamp cover having an opening portion at one end, a light receiving portion of the light source receiving portion including the light reflecting surface on the inner side wall, and a light emitting diode mounted on the receiving portion of the light source, and a display panel mounted in front of the opening portion, which will come from A technique in which light of a light emitting diode is diffused and reflected and made uniform (refer to Patent Document 2). Further, a surface illumination light source including a light source that emits light, an optical transparent light guide body that emits light of the light source and has a radiation surface at a predetermined position in the radial direction, and a radiation surface other than the radiation surface that closes the light guide body are provided a coverless box for the surface, and an inner side reflection method for mounting between the box and the light guide body, and a radiation side reflection method for mounting the light from the light source and reflecting the light from the light source at a fixed ratio Refer to Patent Document 3). The methods disclosed in the above Patent Documents 1 to 3 have problems such as a complicated structure of the light source and poor economy. Although it can be used for surface illumination, it is not easy to respond to tubular illuminations such as fluorescent lamps. On the other hand, a method of achieving a uniform light amount distribution by using a fluorescent lamp as a light source discloses a method of using a light-diffusing film obtained by various methods. For example, a method in which a mixture of a diffusing substance formed of fine particles or the like and a binder resin is applied and laminated (refer to Patent Document 4), and a method in which a non-compatible thermoplastic resin is melt-extruded to form a film (refer to Patent Literature) 5. Patent Document 7, etc.) and a method of controlling the surface shape by performing a shaping treatment such as embossing on the surface of the film (refer to Patent Document 6). However, the previously known light-diffusing film, when used in an illumination device using an LED light source, has poor diffusibility and cannot meet the level of market demand. In particular, since the LED light source has strong directivity of light, the light source point does not disappear and the amount of light around the light source increases (hereinafter referred to as dot loss). In order to suppress this phenomenon, the total light transmittance is lowered, and the amount of light (hereinafter referred to as total light amount) of the entire illumination device is lowered. The present inventors have made efforts to solve the above-mentioned method and reduce the parallel light transmittance, which can effectively improve the dot disappearance and increase the total light transmittance, thereby effectively increasing the overall light amount. For example, in the comparative example of Patent Document 5, it is revealed that the flat light transmittance is low, and the total light transmittance is low and the total light amount is also low. On the other hand, in the example of Patent Document 6, although an example in which the total light transmittance has been improved is revealed, the transmittance of the parallel light is increased, and the dot disappearance is not good. Further, in Patent Document 7, the total light transmittance and the diffuse transmittance are described. When the parallel light transmittance is obtained by passing through the number, the example 1 and the example 2 are 4.6 and 2.1% respectively, which are the same as the example of Patent Document 4. The parallel light transmittance is high and the dot disappearance is poor. On the other hand, liquid crystal display devices (LCDs) are widely used in flat panel displays due to their characteristics such as thinness, light weight, and low power consumption, and their uses are, for example, mobile phones, personal digital secretary (PDA), personal computers, televisions, and the like. Yuan 201038978 pieces, and gradually increase year by year. In the liquid crystal display device, in order to suppress the loss of the light transmission process from the light source to the panel and to increase the brightness on the panel, the backlight unit is mounted on the lower side of the liquid crystal layer. Among them, the liquid crystal layer is irradiated from the back side to make the light-emitting person quite popular, but the arrangement of the light source can be classified into a side type and a lower type. In recent years, backlight units have been used not only in liquid crystal display devices, but also in a wide range of fields such as lamps or electronic signage. The backlight unit is a combination of various optical films such as a backlight, a lens film, a light diffusing film, and a brightness enhancement film, and an optical member such as a diffusing plate, to improve the brightness and brightness of the panel. Usually, two to four pieces are used (refer to Non-Patent Document 1). For example, a lens film for improving brightness is disclosed (refer to Patent Document 8). This method uses the light collecting effect of the lens to increase the brightness, so that the brightness when viewed from the front can be improved, and the brightness when viewed from the oblique angle is higher than that of the front side. The brightness during viewing is drastically reduced. And it is a high-priced item.方法 In order to solve the above-mentioned method of reducing the brightness when viewed from the oblique angle as compared with the front view, the technique of using two anisotropic light-diffusing films in addition to the lens film is used (refer to Patent Document 9). A piece of the above lens film has poor uniformity in brightness, and discloses a technique of combining the lens film and the anisotropic light-diffusing film (refer to Patent Document 10). Further, a method of using a thin film having a higher brightness in the above lens film has been proposed (refer to Patent Document 11), but it is not helpful to reduce the brightness depending on the angle of 201038978. In recent years, high brightness has been achieved by improving the performance of backlights, and in large television or car navigation applications, the improvement in the angular dependence of brightness has been strongly demanded by the increase in frontal brightness. Also, there is a strong demand to reduce wear and tear and reduce the thickness of the device. Here, a test for imparting light diffusibility to a single base film is also discussed (refer to Patent Document 12). The film of Patent Document 12 has a small degree of diffusion, and the inner surface brightness uniformity and pattern masking property are not good. [Patent Document 1] JP-A-2003-186886 (Patent Document 3) JP-A-2008-027886 (Patent Document 4) [Patent Document 5] JP-A-2007-140447 [Patent Document 7] Japanese Laid-Open Patent Publication No. Hei 09-80208 (Patent Document 8) Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. [Non-patent document] 201038978 [Non-Patent Document 1] Uchida Natsuo, "All of the Graphical Electronic Display" (Industrial Survey) P47~48 [Disclosure] The object of the present invention is to solve the above-mentioned prior The problem in the technology is to provide a light diffusing film which is excellent in both light transmittance and diffusivity, for example, when used in a lighting device using a LED light source, in addition to diffusing light of a straight-light led light source into a large area. And don’t see the source of the glare Further, the light-diffusing film and its laminated sheet which have a uniform light amount distribution and a high illuminance and brightness can be obtained by a small number of LED light sources which have suppressed the reduction in the transmittance of light. Means for Solving the Problems The present invention has been made in view of the above circumstances, and a light-diffusing film and a laminated sheet thereof which can solve the above problems are constituted as follows. A light-diffusing film characterized by being a mixture of at least two kinds of incompatible thermoplastic resins, and simultaneously satisfying the following characteristics (1) to (4): (1) total light transmittance 66% or more, (2) Haze is 96% or more, (3) Parallel light transmittance is 2.0% or less, (4) Variable angle photometer in the specification of the invention, diffusion of transmitted light measured by incident angle The ratio (DH/DL) is 2.0 or less, (however, DH and DL are the width of one-half height of the peak height of the variable angle luminosity curve of the transmitted light measured by the automatic variable angle photometer (half 値 201038978 width), The curling direction of the light-diffusing film was measured by fixing it in the vertical direction and the horizontal direction, and a large half-turn width was taken as DH, and a small half-turn width was taken as DL). 2. The light diffusing film according to item 1 above, wherein the DH is 30 degrees or more. 3. The light-diffusing film according to the above item 1 or 2, wherein the curling direction of the light-diffusing film is fixed to the vertical direction and the parallel direction and the horizontal direction of the test article fixing table according to the method of the invention, and the measured The curvature of the main diffusion direction is 4 to 100%. The light-diffusing film according to any one of the above-mentioned items, wherein at least one of the at least two kinds of incompatible thermoplastic resins is formed of a polyolefin resin. 5. The light-diffusing film of item 4, wherein the mixture of at least two kinds of incompatible thermoplastic resins is formed by using two or more kinds of polyolefin-based resins. 6. The light-diffusing film according to the above item 5, wherein the mixture of the at least two polyolefin resins comprises a cyclic polyolefin resin and a polyethylene resin. 7. The light-diffusing film of item 6, wherein the cyclic polyolefin resin has a melt flow rate of less than 0.1 to 1.5 as measured at 230 ° C, and a melt flow rate of the polyethylene resin The system is 5~1 00. 8. The light-diffusing film according to any one of the above items 5 to 7, wherein at least one side of the light-diffusing film formed by the mixture of the at least two kinds of incompatible thermoplastic resins is mainly composed of polyolefin a surface layer formed of a resin. The light-diffusing film of the above item 8, wherein the polyolefin resin forming the surface layer is formed of a polyolefin resin containing a polar group. 10. The light-diffusing film according to item 9 above, wherein the polyisocyanic resin containing a polar group contains at least a carboxyl group. 11. The light-diffusing film according to any one of items 1 to 4 above, wherein the other thermoplastic resin is formed of a fluorine-based resin. 12. The light-diffusing film according to any one of items 1 to 4 above, wherein the other thermoplastic resin is formed of a polyester resin. 〇 13. The light diffusing film according to item 12 above, wherein the light diffusing film is extended by more than 2 times in one direction. The light-diffusing film according to any one of items 1 to 13, wherein at least one side is subjected to a shaping treatment to be roughened. The light-diffusing film according to any one of items 1 to 14, wherein the variable angle photometer described in the specification of the invention has a diffused light ratio (DH/DL) measured by an incident angle of 0 degrees. At least two of the light-diffusing thin films exceeding 2.0 are formed by overlapping in a direction perpendicular to the main diffusion direction. Ο 16. A light-diffusing film laminated sheet characterized by a light-diffusing film according to any one of items 1 to 15 above, having a thickness of 0.1 to 5 mm and a total light transmittance of 70 to 100%. The plastic sheets are laminated. 17. The light-diffusing film according to any one of items 1 to 15, which is an illumination device using an LED light source. 18. The light-diffusing film laminate according to item 16 above, which is an illumination device using an LED light source. An illuminating device using an LED light source, characterized in that the light diffusing film according to any one of the above-mentioned items 1 to 201038978 to 15 is installed on the outer surface or the inner surface of a light-emitting portion of an illumination device using an LED light source . An illumination device using an LED light source, characterized in that the light-diffusing film laminate of the above item 16 is mounted on the outer or inner surface of the light-emitting portion of the illumination device using the LED light source. A backlighting device characterized in that the light-diffusing film according to any one of items 1 to 15 above is mounted on the light-emitting surface of the backlight unit. 22. A backlighting device characterized in that the light-diffusing thin film laminate of the above item 16 is mounted on the exit surface of the backlight assembly. A method of producing a light-diffusing film according to any one of items 1 to 15, which is characterized in that a mixture of at least two kinds of incompatible thermoplastic resins is melt-extruded. 24. The method for producing a light diffusing film according to item 22 above, wherein the resin melted in the extruder is extruded from a die into a sheet shape, and the sheet is pressed by a pressure roller on a cooling roll to be densely combined and cooled. Curing to form a film. Advantageous Effects of Invention The light-diffusing film of the present invention and the laminated sheet thereof are light-diffusing films excellent in both light transmittance and diffusivity, particularly in that the transmittance of straight-through light is small, for example, for use in an LED light source. In the illuminating device, in addition to diffusing the light of the LED light source having a strong straightness into a large area and not seeing the light source point of the strong light, further, since the degree of decrease in the transmittance of the light is suppressed, even per unit area The number of LED sources is reduced and still has a uniform and high amount of light. Therefore, 'there is a point that the light of the LED light source can be suppressed from being straight due to the high straightness, which is the so-called illumination of the LED light source -12-201038978 device, and can maintain the characteristics of the energy-saving LED light source. advantage. Compared with the previously known light diffusing film, the distance between the fluorescent lamp and the light diffusing film or the light diffusing film laminated sheet is shortened even when the diffusing property is greatly improved, for example, when used in a lighting device using a fluorescent lamp as a light source. It still has a high degree of light diffusivity and, therefore, has the effect of reducing the thickness of the illumination device or reducing the number of fluorescent lamps. Further, for example, when a light-diffusing film which is a display device such as a liquid crystal display is used, the thickness of the display panel can be reduced, and the number of films for optical function adjustment such as a brightness enhancement film or a light-diffusing film used for improving the brightness can be reduced. The light-diffusing film of the present invention and the laminated sheet using the same can maintain non-optical properties such as heat resistance, in addition to maintaining the above optical characteristics. Therefore, it can be effectively used for various illuminations such as indoor illumination, illumination of an internal illumination type electronic panel, light irradiation of a photocopier, or illumination of a display device such as a liquid crystal display. Further, when the light-diffusing film of the present invention and the laminated sheet to be used are optical components used as a backlight device, high-luminance, a decrease in the angular dependence of the brightness, and uniformity of the inner surface brightness can be imparted by using only one sheet. The optical characteristics required for the optical material for the backlight device such as the pattern masking property can improve the economic efficiency of the backlight device. In particular, it is advantageous to use a lens film without using a high-priced lens film, and to solve the problem of using a lens film such as a decrease in brightness which occurs when viewing at an oblique angle. The backlight device of the present invention has a front luminance of a height close to that of a backlight device using a lens film, and has a problem of reducing the angular dependence of luminance, that is, a backlight device using a lens film, and therefore has a suppression when used in a large scale -13-201038978 When the television is used, the brightness of the picture is reduced due to the oblique angle viewing. With this feature, it is possible to effectively use a backlight of a display which is mostly viewed from an oblique angle, such as a car navigation. When used in a backlight of an indoor or interior lighting fixture, it has an advantage of uniform illumination over a wide range compared to a backlight using a lens film. Further, since the backlight unit of the present invention can provide all of the above characteristics by using only one single component, it has an advantage of high economic efficiency. Therefore, the backlight device of the present invention can be effectively used in a liquid crystal display device, an indoor illumination, an internal illumination type electronic panel, etc., according to the method for producing a light-diffusing film according to the present invention, and can economically and stably manufacture a book having the above characteristics. The light diffusing film of the invention. [Embodiment] Embodiments of the invention (Optical characteristics) The light-diffusing film of the present invention must simultaneously satisfy the following characteristics. q (1) The total light transmittance is 66% or more, (2) The haze is 96% or more, (3) The parallel light transmittance is 2.0% or less, (4) The variable angle photometer in the invention specification is incident. The diffused light transmittance ratio (DH/DL) measured at an angle of 0 degree is 2.0 or less. (However, DH and DL are the width (half width) of one half height of the peak height of the variable angle illuminance curve of the transmitted light measured by the automatic variable angle photometer, and the curling direction of the light diffusion film is fixed to the vertical direction and the horizontal direction. The direction is determined by the width of the large half-turn as DH and the width of the small half-turn as DL). •14- 201038978 Below, the direction of DH is also called the main diffusion direction. The above total light transmittance is preferably 68% or more, and more preferably. It is particularly good for 80% or more, and more preferably 90% or more. 100% is not more than 100% in principle, so 100% is the upper limit. If the total light is less than 66%, the transmittance of the light from the LED light source is lowered, and the amount of light at the time of the decrease is lowered and the illuminance and brightness of the illumination device are also lowered. The above haze is preferably 97% or more, more preferably 98% or more. 最佳 Optimum. Since the principle does not exceed 100%, 100% is the upper limit. If it is 96%, the light diffusibility is lowered and it is not possible to illuminate uniformly. Therefore, it is not suitable for uniform illumination. It is necessary to increase the number of LED light sources, and it is less than 1.7% of the above parallel light transmittance, and more preferably, even more. Good is 1.2% or less. It is especially good for 〇~1.〇%. 〇% is best _ is not lower than 〇%', so 〇% is the lower limit. If the parallel light passes through 2.0%, the point disappearance deteriorates, and the point of the strong light from the light source is clear, and it cannot be uniformly illuminated, so it is not appropriate.扩散 The diffusivity ratio of transmitted light (DH/DL) (hereinafter referred to as the diffusivity is preferably 1.8 or less, especially preferably 1.6 or less, particularly preferably 〇.7 to 1.3. When the diffusivity ratio (DH/DL) exceeds 2.0, The anisotropy of light diffusion is not suitable because the amount of light diffused to the specific direction 'lights, that is, the illuminance and the brightness, is not appropriate. The above diffusion ratio is determined by the following method. <Measurement method of diffuse transmittance ratio of transmitted light> Using an automatic variable angle photometer (GP-200: Murakami Color Research Institute 70% is the best. The transmittance is used for the sake of discomfort. 100% haze is low. For the economy. 1 · 5 % to: Because the original rate exceeds the Chu to see the ratio), the increase is higher than the third, the uniformity of the shares -15-201038978 system system) for the determination. Through the measurement mode, the angle of incidence of light: 〇 ° (for the test surface, the angle of the right and left, right and left at right angles), the angle of light: a 90 ° ~ 90 ° (angle on the equatorial line), the filter: Using ND10, beam aperture: 10.5mm (VS-l 3.0), light-receiving aperture: 9.1mm (VS-3 4.0) and variable angular separation of 0.1 degrees, determine the change when SENSITIVITY or HIGH VOLTON is changed. The peak of the light is 40 to 90% of the graph, and the measured width 〇 (half width) of the height of the height of the peak of the variable angle luminosity curve of the transmitted light. The above measurement is performed by fixing the curl direction of the light-diffusing film in the vertical direction and the horizontal direction to obtain a large half-width which is obtained as DH, and the smaller one is DL, and obtaining a diffusion ratio (DH/DL) (Reference) Figure 1). When the surface roughness of the light-diffusing film differs, the surface having a rough surface is fixed to the light-receiving side to perform the above measurement. Further, the face of the moving light receiver is defined as the equatorial plane. The light-diffusing film of the present invention satisfies the above characteristics at the same time, and can sufficiently exhibit the effect of the present invention, and the DH is preferably 30 or more. More preferably, it is 35 degrees or more, and particularly preferably 40 degrees or more. If dh is less than 30 degrees, the diffusibility of light is lowered, and it is not easy to provide uniform illumination, which is not appropriate. In order to illuminate evenly, it is necessary to increase the number of L E D sources, which is less economical. (Variation of Light) The degree of curvature of the present invention was measured by the following method. <Measurement method of the degree of curvature of light> -16-201038978 The measurement was carried out using an automatic variable angle photometer (GP-200: manufactured by Murakami Color Research Institute Co., Ltd.). Through the measurement mode, the incident angle of light is 0. (For the test surface, the angle is at right angles up and down, left and right), light receiving angle: 90°~90° (angle on the equator line), filter: ND10, beam aperture: l〇.5mm (VS -l 3·〇), measured by the condition of 9.1 mm (VS-3 4.0) and the angular separation of 0.1 degree, and the peak of the transmitted light is determined by changing the setting of SENSITIVITY or HIGH VOLTON. 40 to 90%, the measured height of the peak of the light passing through (H0), and the change of the incident angle of the light to 60° (the angle on the equatorial plane), when measured under the same conditions as the above conditions The height (H60) at which the angle of the peak of the transmitted light is 0 degrees. Using the H60 and H0 obtained by this method, the degree of curvature was calculated by the following formula. The degree of curvature of light = H60 / Η〇χ 1 00 (%) (1) Refer to Figure 2. The plane of the moving receiver is defined as the equatorial plane. The degree of curvature of the light is determined by measuring in the main diffusion direction. Ο When there is a difference in the surface roughness of the light-diffusing film for the backlight unit, the above measurement is performed by fixing the direction in which the light passes in the same direction as that actually used in the backlight unit. The degree of curvature of the above light is preferably from 6 to 100%, more preferably from 8 to 100%. If the degree of curvature of light is less than 4%, the effects of the present invention described above cannot be sufficiently exerted, which is not appropriate. This characteristic is, for example, the degree of the effect of the distortion of light in the film when it is incident on the light diffusing film for the backlight unit, that is, the degree of the degree of light emitted from the high angle -17-.201038978 toward the front side. . It can also be a scale indicating the effect of collecting light. The light-diffusing film of the present invention has a larger bending effect than the previously known light-diffusing film or lens film. Therefore, the effects of the present invention can be effectively exerted. For example, when used in a backlight device for a liquid crystal display, a piece of a previously known lens film, a light diffusing film (sheet), and a light diffusing plate member may be used, respectively, to satisfy the above-described characteristics of any one of them. It is the founding of the present invention that meets the desirable characteristics of all of the features at the same time.尙 Although the reason for attaching this ideal characteristic is unknown, the inference is achieved by meeting the above-mentioned majority of optics. For example, the high degree of curvature of light is dependent on the angle of brightness, and the high degree of diffusion contributes to the uniformity of the inner surface brightness or the masking property. (Surface roughness of the surface of the light-diffusing film) The light-diffusing film of the present invention preferably has a surface roughness of at least one surface which is in the same direction. That is, the average surface roughness of the curling direction of the light-diffusing film and the direction perpendicular to the direction is measured, and the ratio of the average surface roughness RaV to the ruler & 11 measured, that is, the surface roughness ratio (1) is measured. ^乂/1^15) is preferably from 0.83 to 1.20. If it is out of this range, for example, the anisotropy of light diffusion, that is, the above-described diffusivity ratio (DH/DL), the amount of light, that is, the uniformity of illuminance or brightness, is not appropriate. The above surface roughness is preferably from 0.91 to 1.1. (Configuration of Light-Diffusing Film) The light-diffusing film of the present invention is formed by a mixture of at least two kinds of incompatible thermoplastic resins. Between the above-mentioned at least two kinds of incompatible thermoplastic resins -18- 201038978 In the form, the respective resins of the continuous phase and the dispersed phase are independently present, that is, the sea/island structure, and the two resins may form a co-continuous phase. The structure. The above characteristics are exhibited by the refraction or scattering of light at the resin interface. The film thickness of the light-diffusing film of the present invention is not particularly limited, and is preferably from 10 to 1 000 μm. Especially suitable 30~5 00 μιη. (A mixture of at least two kinds of incompatible thermoplastic resins) In the present invention, a thermoplastic resin used in a mixture of at least two kinds of incompatible thermoplastic resins, such as a polyethylene resin, a polypropylene resin, and a poly a polyolefin resin such as a butylene resin, a cyclic polyolefin resin or a polymethyl pentene resin, a polyester resin, an acrylic resin, a polystyrene resin, a polycarbonate resin, a fluorine resin, and Its copolymer and the like. From such a thermoplastic resin, at least two kinds of incompatible (incompatible with each other) thermoplastic resin may be selected, but the above characteristics and economical properties can be stably achieved, and at least one polyolefin-based resin is preferably formed. . Among the two types of resins, the other resin is preferably a polyolefin resin, a polyester resin, a fluorine resin or the like. Consider the demand characteristics other than optical characteristics ^ or economical, etc., and choose appropriately. In particular, from the viewpoint of light resistance and economy, it is preferred that both of them are polyolefin-based resins. When both types are polyolefin-based resins, the combination is not particularly limited, and the difference in refractive index between the two types of polyolefin-based resins is preferably in the range of 0.003 to 0.07. More preferably, it is in the range of 0.005 to 0.05, and more preferably 0.0 1 to 0 · 0 2 . When this refractive index difference is within this range, the light-diffusing film having the above optical characteristics can be more stably obtained. For example, if the refractive index difference exceeds 0.0 7, it helps to make the haze and parallel light transmittance within the above range, but the full light -19-201038978 line transmittance is not easy to reach equilibrium. On the other hand, if it is less than 0.003, it is easy to achieve total light transmittance, but it is difficult to achieve a balance between haze and parallel light transmittance. Therefore, within the above range, various optical characteristics as described above can be simultaneously satisfied. If it is out of the above range, even if the above mixing ratio and melt flow rate are satisfied, it is impossible to satisfy all the characteristics. The type of the polyolefin-based resin which is in contact with the above-mentioned refractive index difference is not particularly limited. The combination of the cyclic polyolefin-based resin and the polyethylene-based resin can satisfy the above characteristics and is excellent in economy, so that it is suitable. . The cyclic polyolefin-based resin is, for example, a cyclic polyolefin structure such as a tetracycline or a tetracyclic quinone. For example, (1) a ring-opening (co)polymer of a decene-based monomer is added to maleic acid or cyclopentadiene to carry out polymer-modified hydrogenation, and (2) a deuterated system is used. A resin in which a monomer is subjected to addition polymerization, a resin in which (3) a decylene-based monomer, and an olefin-based monomer such as ethylene or an α-olefin are subjected to addition polymerization. The polymerization method and the method of adding hydrogen can be carried out in accordance with a general method. The π ^ polyethylene resin may be a single polymer or a copolymer. In the case of a copolymer, it is 50 mol% or more, preferably an ethylene component. The density of the resin, the polymerization method, and the like are also not limited, but a copolymer having a density of 0.909 or less is preferably used. For example, copolymers such as propylene, butene, hexene and octene. The polymerization method may be any one of an aromatic cycloolefin metal derivative catalytic method and a non-aromatic ring rare metal derivative catalytic method. Particularly, from the viewpoint of stably attaching high diffusibility, a block copolymer of ethylene and octene is preferably used. For this resin, for example, INFUSE(TM) manufactured by Daewoo Chemical Co., Ltd. -20-201038978 can be used. The melt flow rate of the thermoplastic resin which is at least two kinds of incompatible thermoplastic resins is preferably added to the difference in melt flow rate of each of the thermoplastic resins. Thereby, the above optical characteristics can be attached more stably. For example, when a polyolefin resin is used in both of the above-mentioned types, the thermoplastic resin having a low melt flow rate preferably has a melt flow rate of from 0.1 to 1.5 or less measured at 270 °C. More preferably 0.1 to 1.2, and particularly preferably 0.1 to 1.0. When it is less than 0.1, the stability of the film formation is lowered, which is not appropriate. On the other hand, when it is more than 1.5 〇 or more, the surface roughness ratio or the light diffusivity ratio is increased, and the optical characteristics such as an increase in the anisotropy of light diffusion are deteriorated, which is not preferable. On the other hand, the thermoplastic resin having a high melt flow rate preferably has a melt flow rate of 5 to 100 as measured at 230 °C. More preferably 1〇~1〇〇, especially good 15~100. If it is less than 5, the optical characteristics such as an increase in the anisotropy of light diffusion are deteriorated, which is not appropriate. On the other hand, when it exceeds 100, the stability of the film formation is lowered, which is not appropriate. When a mixture of at least two kinds of incompatible thermoplastic resins is used as a mixture of the above cyclic polyolefin resin and a polyethylene resin, a cyclic polyolefin resin is preferably used as the resin having a low melt flow rate. A polyethylene resin is preferably used as the resin having a high melt flow rate. The blending ratio of the at least two kinds of incompatible thermoplastic resins is preferably from 10/90 to 90/10, more preferably from 20/80 to 80/20, particularly preferably from 30/70 to 70/30. Within the above range, the various optical characteristics described above can be simultaneously met. If it is not within the above range, even if it meets the following, it will not be able to meet all of the features of -21- 201038978 or some of its characteristics. The above resin may be selected from resins which are generally commercially available and which are highly versatile, and may be used in a more stable manner, and a special product may be used. (Layer of Polyolefin Resin Formation Layer) In the present invention, when a mixture of at least two kinds of incompatible thermoplastic resins is used, and both types of polyolefin resin are used, it is preferable that at least two kinds of polyolefin systems are used. At least one side of the layer formed of the mixture of the resins is formed by laminating a surface layer mainly composed of a polyolefin resin. Hereinafter, a layer formed of a mixture of at least two kinds of polyolefin resins is simply referred to as a light diffusion layer. When melt-extruded to form a film, it occurs at the exit of the extrusion die, for example, a phenomenon called "eye stain" which occurs as a result of the deterioration of the resin at the exit of the extrusion die, because the surface layer can be used Since it is suppressed by formation, it is suitable for continuous film formation for a long time and stability. Further, since it is possible to suppress the shielding property of the light-diffusing film which occurs when a flexible polyolefin-based resin such as a block copolymer of ethylene or octene is used, it is suitable.聚烯烃 The polyolefin-based resin formed on the surface layer described above is preferably a crystalline resin because it has an effect of suppressing the shielding property. The polyolefin resin to be used for the formation of the above surface layer is preferably a polyolefin resin containing a polar group. Therefore, it is suitable to improve the adhesion of the light-diffusing film to other materials. For example, in the production of a light-diffusing film laminate as described later, it is suitable because it can improve the adhesion to a plastic sheet. Further, it is widely used as an optical material, and it is preferably used because it can be attached to an acrylic resin or a polycarbonate resin. -22- 201038978 The above-mentioned polyolefin resin containing a polar group preferably has a skeleton of at least one of ethylene, propylene, butylene, hexene, octene, methylpentene and a cyclic olefin. A homopolymer of the above-mentioned monomers of one type may be used, or a copolymer of two or more kinds of monomers may be used. The above polar group-containing polyolefin resin of the present invention preferably contains at least one kind of polar group. Polar groups such as carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, hydroxyl groups, glycidyl groups, isocyanate groups, amine groups, oxime imido groups, oxazolines, ester groups, ether groups, metal carboxylates, sulfonates An acid metal salt group, a phosphonic acid metal salt group, a tertiary amine salt group, a 4-grade amine salt group, and the like. It may contain one or more of these polar groups. The composition of the polyolefin-based resin constituting the light-diffusing layer, the type of the component to be in contact with the object, the desired adhesion, and the like may be appropriately selected, and at least the carboxyl group-based embodiment is preferably used. In the polyolefin resin containing a polar group in the present invention, the polar group may be directly introduced into the polymer chain of the polyolefin resin, or may be introduced into another resin to be added and mixed. Depending on the situation, the polyolefin resin of the present invention may be modified by, for example, a carboxylic acid group or a hydroxyl group introduced into the terminal or the inside of the molecular chain to react with a compound reactive with such a group, and may be used. In the present invention, the polyolefin resin containing the above-mentioned polar group may be used singly or in combination of two or more kinds thereof. Further, it may be a polyolefin resin containing no polar group or a combination of other types of resins. When the composition is blended, the polyolefin resin containing the above polar group is preferably contained in an amount of 10% by mass or more. More preferably, it is 30% by mass or more. -23- 201038978 € w The polyolefin resin of the @-based group is preferably formed of a crystalline resin. Preferably, the melting point is from 1 〇〇 to 18 〇. (A) The polyolefin resin containing i: the polar group is not particularly limited as long as it has the above characteristics. For example, a commercially available resin can be suitably used as the binder polyolefin resin. For example, an aduman resin ( TM, manufactured by Mitsui Chemicals Co., Ltd., Maudeke Resin (TM, manufactured by Mitsubishi Chemical Corporation) or Adudecex Resin (TM, manufactured by Nippon Polyethylene Co., Ltd.) and Montesto Resin (TM, manufactured by Sumitomo Chemical Co., Ltd.) 'But it is not limited to this. · By layer which is formed of a polyolefin resin containing a polar group, it is laminated on the light-diffusing layer, and the light-diffusion film which is a single layer of the light-diffusion layer can be improved. Adhesion to other materials. Improves the film's resistance to clogging or slidability' and improves the operability of the light-diffusing film. It also provides thermal adhesion to various materials. (Roughening by shaping treatment) In the light-diffusing film of the invention, at least one side of the film obtained by the above method is preferably roughened by a shaping treatment. ^ The roughening treatment is performed on the surface of the light-diffusing film obtained by the above method to form Bump The roughening is not particularly limited, and it may be subjected to matte processing, embossing, etc. The roughening treatment is performed by, for example, forming a concave-convex (lattice-like irregularities, irregular irregularities, etc.). The roll is formed by pressing the sheet material on the roll having the uneven portion. The formation or depth of the surface unevenness formed by the roughening treatment is not particularly limited, but the shaped surface is formed. The concavity and convexity is preferably a shape of irregular directionality which is not aligned in a specific direction. That is, a processing method of extinction-24-201038978 processing or pear processing is usually used. It is also possible to use a rough surface which is formed by special surface irregularities. The above-described roughening treatment may be an in-line processing method performed in a film forming step of a film, or an off-line processing method performed in other steps. The light diffusing film laminated sheet described later may be shaped and thickened. By the roughening of the above-mentioned shaping treatment, the blocking resistance and the slidability of the film can be improved, the operability of the light-diffusing film can be improved, and the light diffusion degree can be improved. The film ratio of the light diffusing film of the present invention is not particularly limited, and is preferably 10 to 1000 μm, more preferably 30 to 500 μm. The light diffusing film of the present invention. It can be used in one piece or in two or more layers. When two or more sheets are used in combination, they can be used only by overlapping, and can also be used by sticking adhesive or adhesive. The present invention also includes a form and system. When two or more sheets are used in combination, each of the films is a light-diffusing film which does not conform to the characteristics of the present invention, and is overlapped to conform to the characteristics of the present invention. For example, several kinds of ruthenium films having high anisotropy are mainly diffused. The method of overlapping the directions in the vertical direction to reduce the diffusion ratio and conforming to other optical characteristics is an ideal implementation mode. By this method, the degree of anisotropy can be widely suppressed, which is an ideal implementation. Style. The light-diffusing film of the present invention may be used by being superposed on another work film such as a light-diffusing film or a lens film having other characteristics. When using this method of use, it can be used only by overlapping, and it can also be used by sticking adhesive or adhesive. -25- 201038978 (Manufacturing method of light-diffusing film) The method for producing the light-diffusing film of the present invention is not particularly limited as long as it satisfies the above optical characteristics, and is preferably formed by melt extrusion molding from the viewpoint of economy. method. In the present invention, in order to impart light diffusibility, it is possible to reduce the clogging of the filter film of the molten resin in the film forming step by performing the melt extrusion molding method without containing the non-melting fine particles, and it is excellent in productivity. The resulting film has a high degree of clarity. Ο There is no particular limitation on the film forming method by the above melt extrusion molding method, for example, any of the T die method and the blow molding method. It can be an unextended film or extended. The preferred aspect of the present invention is in an extruder in which a molten resin is extruded from a die into a sheet shape, and the sheet is pressed against a cooling roll by a press roll to form a film by compacting and cooling. The content is not particularly limited as long as it conforms to the pressure roller in the chill roll to press the sheet to make it tight. For example, it may be pressed by a press roll of a smaller diameter than a commonly used chill roll, or may be extruded between two chill rolls of the same diameter and crimped by the two chill rolls. In this method, it is also possible to use a roll having a roughening treatment on the surface of the squeezing roller and/or the chill roll, and at the same time, roughening the above-described shaping treatment. By the above treatment, the isotropic property of the light diffusion characteristics of the light-diffusing film can be improved. One of the characteristics of the light-diffusing film of the present invention must be diffused in the same direction in the same direction. That is, because of the isotropic light-diffusing film, it is not limited by the extension of the 26-201038978 extension. For example, when a polyester system is used for the light diffusion layer, one-axis stretching is preferred. By the above-described treatment, the island phase is elongated in the direction in which it is stretched, and the light diffusibility in the direction perpendicular to the alignment of the island phase is remarkably enhanced, and the object of the present invention can be ensured. However, the light-diffusing film obtained by this method is mostly anisotropic and has a diffusion ratio exceeding the range of the present invention. Therefore, in the preferred embodiment, as described above, two or more films are stacked so that the main diffusion direction is drooped and used.光 The light-diffusing film of the present invention may be a single layer or a layer structure of two or more layers. In the case of a multilayer structure, if at least one layer is formed of the above-described layer formed of a light-diffusing film, the other layer may be a transparent layer which is simple without light diffusion. Moreover, it may be a structure of a full-layer light-diffusion layer. In the case of the above multilayer structure, it can be produced by a multilayer co-extrusion method, and it can be carried out by extrusion lamination or dry lamination. The above mixture of at least two kinds of incompatible thermoplastic resins is blended in an extruder or the like of the film forming step, and each of the thermoplastic resins is blended, and then used as a mixture in advance by kneading or the like. (Mechanism) The present invention must simultaneously satisfy the above-mentioned various optical characteristics such as total light transmittance, parallel transmittance, haze, diffusivity, and diffusivity ratio, and at the same time conform to most characteristics, firstly, the previously known light diffusion cannot be achieved. The height of the characteristics achieved. Thereby, a high-performance light-diffusing film suitable for use in an illumination device or a backlight device for L E D can be obtained. The above characteristics each include a characteristic indicating a behavior of a bipolar back. The resin is stretched in the direction of high diffusion, and the state is as straight as it is, and it can be pre-light. Off film source 〇 For example -27- 201038978 Total light transmittance and other characteristics indicate a double-reverse action. On the other hand, parallel light transmittance, haze and diffusivity, in terms of macroscopic view, indicate the characteristics of proportional behavior, and in microscopic terms, it is not as close as proportional. Therefore, it is not easy to clearly express the contribution to the individual elements of the respective characteristics, but the resin characteristics such as the refractive index difference or the melt flow rate of the above-mentioned incompatible resin, or the type or mixture ratio of each resin, etc. Within the scope, it can be achieved with stability. The diffusion ratio of one of the above characteristics is greatly changed due to the difference in the manufacturing apparatus used, and as a result of the investigation, in the above-described melt film forming method, the molten resin is extruded from the die into the extruder. In the form of a sheet, the sheet is pressure-bonded to a chill roll, and the sheet is pressure-sealed and solidified to form a film, whereby it can be produced more stably. The above diffusion ratio is governed by the influence of the phase structure formed by the two kinds of incompatible resins of the light diffusion layer. For example, if it is a sea/island structure, it is governed by the anisotropy of the shape of the island. It is proportional to the anisotropy of the island shape and increases the diffusion ratio. That is, it is important to reduce the anisotropy of the shape of the island, that is, to improve the isotropic nature of the shape of the island. With the above manufacturing method, although the mechanism for improving the isotropic property of the island shape is not clear, the inference is as follows. The shape of the island component in the sheet extruded by the melt extrusion method is distributed in the die, and the shape in the direction of extrusion is tapered. After being extruded from the die, the sheet is inclined in a molten state, and the shape of the island is tapered in the extrusion direction, and is cooled and solidified in this state, and generally, the shape is elongated in the direction of the extrusion direction. However, it is immobilized, so the diffusivity of the light-diffusing film is higher than that of -28 - 201038978 '. However, according to the above manufacturing method, the sheet at the inlet of the pressure-bonding portion is pressed by the pressure roller on the chill roll, and is in an uncured state, so that a liquid storage area (also referred to as a hopper) is formed at the inlet of the pressure. ), the unreacted resin is retained in this zone, and the island component which is thinned in the extrusion direction, the surface tension, causes the force of the same direction droplets to return to the original shape, and the anisotropy is changed to become more isotropic. Since the shape is solidified by the shape of the deformation, the isotropy of the island shape is improved, and as a result, the light diffusivity is the same, and the diffusivity is stabilized in the above range. (Light-diffusing film laminated sheet) Another invention of the present invention is a light-diffusion diffusing property obtained by the above method and having a thickness of 0.1 to 5 mm and a total light transmittance of 70 to 100%. Film laminate. The light-diffusing film obtained by the above method has the above-mentioned excellent characteristics and can be economically produced, but in some applications, it cannot satisfy characteristics other than characteristics, such as heat resistance, heat-resistant dimensional stability, mechanical properties or Characteristics such as flame retardancy. By laminating a transparent plastic sheet with a light diffusing film, it is possible to complement the general characteristics of the market in addition to the optical characteristics. The transparent plastic sheet used in the present invention can conform to the above-mentioned characteristics of the thickness line transmittance, and does not limit the type or layer composition of the resin to be used in the thickness of the transparent plastic sheet of the present invention, and is preferably 0.5 to thinner than 0.1 mm. Enhancement or complement is not effective. If it is exceeded, it is not economical and detracts from softness. In the case of the connection, the curing state of the joint portion is moderated by the surface, and the plasticity of the plastic which is cooled and the light diffusion is increased. , 3 m m. 5mm to -29- 201038978 The total light transmittance of the transparent plastic sheet used in the present invention is preferably 80 to 100%. More preferably 85 to 100% » If it is less than 70%, the characteristics of the above light-diffusing film cannot be effectively exerted. It is advisable to use a high total light transmittance and non-diffusion. Further, it is also possible to use a diffuser as the plastic sheet to exert a laminated effect. The resin to be used for the plastic sheet is not particularly limited, and a resin for optical use such as a polyester resin, an acrylic resin, a styrene resin, a cyclic polyolefin resin, or a polycarbonate resin is preferably used.制 The method for producing the light-diffusing film laminate is not particularly limited. For example, a method of adhering a light diffusing film to a plastic sheet. When it is pasted with an adhesive or a binder, specifically, an adhesive such as a rubber-based adhesive, an acrylic adhesive, a silicone adhesive, or a vinyl adhesive. Since the light-diffusing film laminate of the present invention may be used at a high temperature, it is preferably an adhesive which is stable at a normal temperature of ~120 ° C. Among them, acrylic acid adhesives are widely used because of low prices. Regardless of the type of adhesive used, the thickness is preferably from 55 to 50 μm.黏 Adhesives are adhesives that are bonded, for example, by the aid of heat or a catalyst. Specifically, for example, an anthraquinone-based adhesive, a polyurethane-based adhesive, a polyester-based adhesive, an epoxy-based adhesive, a cyanoacrylate-based adhesive, an acrylate-based adhesive, or the like can be used. Since the light-diffusing film laminate of the present invention may be used for high temperature, it is preferably an adhesive which is stable at a normal temperature of ~120 °C. Among them, the epoxy-based adhesive is excellent in strength and heat resistance and can be suitably used. Since the cyanoacrylate-based binder is excellent in immediate effect and strength, it can be used for the production of an efficient laminated sheet. Polyester adhesive is excellent for strength and workability, -30- 201038978, so it is especially suitable for the production of laminated sheets. Such adhesives are classified into a heat-curing type, a hot-melt type, a two-liquid mixing type according to the bonding method, and a heat-hardening type or a hot-melt type which can be continuously produced is preferably used. Regardless of the binder used, the thickness is preferably 0.5 to 50 μm. The method of adhering the above-mentioned plastic sheet to a light-diffusing film with an adhesive or a binder is carried out by using a roll-to-roller or a roll-to-sheet treatment of a laminator to obtain a roll-shaped or sheet-shaped article. For example, when a binder is used, a binder is applied to either the plastic sheet or the light-diffusing film, dried, and then coated with a target material, and laminated by a roll. The coating method of the adhesive is various depending on the type of the substrate or the adhesive, and the gravure coater method, the standard applicator method, and the reverse coater method are often used. The gravure coater method rolls a gravure roll partially impregnated with a binder so that the film conveyed by the backing roll comes into contact with the gravure roll to which the adhesive has adhered, thereby performing coating. The amount of coating can be adjusted by controlling the number of rolls of the rolls, the viscosity of the adhesive, and the like. Although the reverse coater method is similar to the gravure coater method, the meter attached to the 〇 is used to adjust the amount of the adhesive adhered to the coating roll. When the above paste is applied, it can be heated according to the demand. Further, in order to have the necessary adhesive strength, heat treatment may be performed after lamination. When pasting with an adhesive, a double-sided adhesive sheet can also be used. When using this method, an optically high transparent type of adhesive should be used without particular limitation. For example, a light diffusing adhesive sheet can also be used. When the adhesive sheet is used, the adhesive layer can also be made to have light diffusibility. The present invention can also be carried out by integrating the production of the above-mentioned light-diffusing film with the production of the above-mentioned light-31 - 201038978 diffusion film laminated sheet. In other words, the thermoplastic resin composition constituting the light-diffusing film may be melted and extruded on the surface of the transparent plastic sheet to be directly laminated, that is, produced by extrusion. The above-described roughening treatment can also be carried out in the step of the melt extrusion lamination method. When the extrusion lamination method is carried out, in order to improve the adhesion or adhesion durability of the light-diffusing film and the transparent plastic sheet, it is preferable to adopt a method of using a transparent plastic sheet which has been subjected to an adhesion-adhesive coating treatment and is easy to be bonded.光 The light-diffusing film or the light-diffusing film laminated sheet of the present invention is preferably a light-diffusing film using an illumination device using an LED light source because of the excellent optical characteristics as described above. However, there is no particular limitation, and for example, it can be effectively used for an illumination device using a light source other than an LED light source such as a fluorescent lamp. For example, when used in an illumination device of a fluorescent light source, even if the distance between the fluorescent lamp and the light diffusing film or the light diffusing film laminated sheet is pulled, the light diffusing property is high, and therefore, the thickness and the thickness of the lighting device are reduced. The number of fluorescent lights and other effects.光 The light-diffusing film or the light-diffusing film laminated sheet of the present invention can be reduced in comparison with the previously known light-diffusing film by greatly improving the diffusibility thereof when used for brightness enhancement of an LCD using a fluorescent lamp as a light source The number of films for optical function adjustment such as a light-diffusing film. (An illuminating device using an LED light source) According to another aspect of the invention, the light diffusing film and the light diffusing film laminated sheet described above are formed on the outer surface or the inner surface of a light-emitting portion of an illuminating device using an LED light source. Lighting device for led light source. -32- 201038978 A previously known light-diffusing film is usually used on the outer surface or the inner surface of the light-emitting portion of the light guide plate. When the light-diffusing film of the present invention and the laminated sheet thereof are used as far as possible from the LED light source, the light diffusing property and the point disappearing property are improved. Therefore, it is preferable to use the illumination device using the LED light source in the above method. The method of dispersing the light-diffusing film and the laminated sheet thereof is not particularly limited. For example, an adhesive or an adhesive is adhered to the outer surface or the inner surface of the outer panel of the light-emitting portion, and only the device is covered. If it is pasted, it can be fixed by using an adhesive 〇 or a binder as a whole, or it can be partially used and fixed. In the case of a fluorescent lamp-like tubular illumination device, the light-diffusing film or its laminated sheet may be inserted into the inner surface of the outer tube along the inner side of the tube. It is also possible to install only the light-diffusing film of the present invention or a laminated sheet thereof without an outer sheet. (Usage method for use as a backlight unit) The light-diffusing film or the light-diffusing film layered sheet of the present invention can be suitably used as a member for improving the brightness or illuminance of the backlight unit because of the above-described excellent optical characteristics. ® It is important to attach the above-described light-diffusing film or light-diffusing film laminate of the present invention to the light-emitting surface of the backlight unit. In this case, the method of mounting the light-diffusing film or the light-diffusing film laminate is not particularly limited. They can be installed only by overlapping, or they can be fixed by adhesive or adhesive. It can also be fixed with double-sided tape. Further, it may be mounted on the lowermost portion of the liquid crystal panel provided on the upper surface of the backlight unit. By this measure, the effects of the present invention described above can be exerted. -33- 201038978 (Backlighting module). The backlight unit using the light-diffusing film or the light-diffusing film laminated sheet of the present invention may be a member having an emitting surface on at least one side, and the structure and the like are not limited at all. It can be side light or down. In the case of the side light mode, the structure of the light guide plate is also not limited. The type of reflective film or reflector used in the backlight assembly is also not limited. It can be any of a white reflection type, a metal reflection type, and the like.光源 The light source used for the backlight unit is also not limited. It may be, for example, any of an electric bulb, a light emitting diode (LED), an electroluminescent panel (EL), a cold cathode tube (CCFL), and a hot cathode tube (HCFL), or a combination thereof or other light source. The light-diffusing film or the light-diffusing film laminated sheet of the present invention is required to provide a high-brightness, a decrease in brightness angle dependency, an inner surface brightness uniformity, and a pattern masking property, etc., even if only one such component is used. The optical characteristics are important, but it is important to use two sheets, or to use them together with previously known lens films or light diffusing films.其他 Other light diffusers or light diffusers can be used. In this case, most types of optical parts can be used. It should be appropriately selected and used according to the characteristics of the market demand or economy. The following examples are intended to describe the present invention in more detail, but the present invention is not limited by the following examples, and may be appropriately modified within the scope of the gist of the present invention, and the like is included in the technology of the present invention. range. -34- 201038978 The measurement 'evaluation method used in the examples is as follows. "Parts" in the example means "mass share j," "%j means "% by mass". <Total Light Transmittance, Parallel Light Transmittance, and Haze> The haze meter "NDH-2000" manufactured by Nippon Denshoku Industries Co., Ltd. was used in accordance with JIS K 7136. This measurement was carried out by fixing the test piece fixing portion so that the curling direction of the light-diffusing film was perpendicular, and the measurement enthalpy obtained by the measurement was used. When the surface roughness of the light-diffusing film differs, the surface having a rough surface is fixed to the light-receiving side and measured. For example, a light-diffusing film having only one side roughening treatment is measured in the direction in which light passes in actual use. <Diffraction ratio of transmitted light> The measurement was carried out using an automatic variable angle photometer (GP-200: manufactured by Murakami Color Research Co., Ltd.). Through the measurement mode, the angle of incidence of light: 〇 ° (for the test surface, the angle of the right and left, right and left at right angles), the angle of light: a 90 ° ~ 90 ° (angle on the equator line), filter: use ND10, beam aperture: 10.5mm (VS-l f) W 3.0), measured by the aperture: 9.1mm (VS-3 4.0) and the angular separation of 0.1 degrees, find the setting of SENSITIVITY or HIGH VOLTON The peak of the transmitted light is measured at 40 to 90% of the graph, and the measured width of the height of the peak of the variable angle illuminance curve of the transmitted light is half the width (half width). The above measurement is performed by fixing the curling direction of the light-diffusing film in the vertical direction and the horizontal direction, and the obtained half-width is a DH, and the smaller is DL, and the diffusion ratio (DH/DL) is obtained (Reference). Figure 1). -35- 201038978 When the surface roughness of the light-diffusing film differs, the above-described measurement is carried out by fixing the rough surface to the light-receiving side. <Variation of light> The measurement was carried out using an automatic variable angle photometer (GP-2 00: Murakami Color Research Co., Ltd.). Through the measurement mode, the incident angle of light is 0. (For the test surface, the angle is upright, left and right at right angles), the angle of acceptance: one 90. ~90. (angle on the equator line), filter: using ND10, beam aperture: 10.5mm (VS-l 〇 3.0), receiving aperture: 9.1 mm (VS-3 4.0) and varying angular spacing of 0.1 degrees Find the height (H0) of the measured peak of the transmitted light by changing the SENSITIVITY or HIGH VOLTON setting so that the peak of the transmitted light is 40 to 90% of the graph, and change the incident angle of the light to 60°. The height (H60) at the angle of 0° of the peak of the transmitted light when measured under the same conditions as the above conditions, except for the angle on the equatorial plane. Using the H60 and H0 obtained by this method, the degree of curvature was calculated by the following formula. Light distortion = H60 / ΗΟχ 1 00 (%) (1) ® Refer to Figure 2. The plane of the moving receiver is defined as the equatorial plane. The degree of curvature of the light is determined by measuring in the main diffusion direction. When the surface roughness of the light-diffusing film differs, the above measurement is carried out by fixing the direction in which light passes in the same direction as in actual use. <Light resistance> Using a calendering aging tester (S3 00, manufactured by Sikai Testing Instruments Co., Ltd.) 'Emission radiance of the test surface: 78 W/m 2 , wavelength range: 00 to 400 nm, -36 to 201038978, continuous irradiation, There are rainfall conditions (12 minutes of rain in 60 minutes), exposed to 63 ° C ><50% RH environment for 400 hours, evaluation of color change (Δ* ab) 〇 <Average surface roughness ratio> The universal surface shape measuring instrument MODEL SE - 3C manufactured by Ogata Research Co., Ltd. was used, and the longitudinal magnification: 2000 to 10000, cutoff: 〇.25 mm, measurement length · 8 mm, measurement Speed measurement: 〇. 5 mm / min. The above measurement system is a surface roughness ratio (RaV/RaH) which is a ratio of RaV to RaH of each of the obtained average surface roughness measured by measuring the curl direction of the light-diffusing film and the average surface roughness in the direction perpendicular thereto. This measurement was performed 5 times separately, and the average enthalpy was used. <Melting flow rate of thermoplastic resin> The measurement was carried out under the conditions of 230 ° C and 2.16 kgf in accordance with JIS K 7210 A. A part of the resin is determined by the conditions of the examples. <Evaluation of Light Diffusivity When Using Illumination Device Using LED Light Source> Using a 40 W neon light transparent lamp cover type fluorescent lamp type led illumination lamp (MLT-40KC) manufactured by Maurice Adhere the light-diffusing film or the light-diffusing film laminate to the surface of the transparent lamp cover, 5 cm directly above, with a digital camera (KONICA MINOLTA, Tima A700, shooting conditions, manual mode, shutter speed 1 / 1 000 sec. , Aperture 値 6.3) Photographs of the parts of the illumination were taken, and each performance evaluation was performed on the basis of the following criteria. (1) The brightness is based on the brightness of the light-diffusing film of Example 1, and the brightness is brighter than that of ◎, the brightness of the same degree is 〇, and the brightness is worse -37-201038978 〇〇 X. Brightness is determined by the whiteness of the photo. (2) Point disappearance In the above photo, the following judgment is made. Those who can't see the light source: ◎ Those who see the light source slightly: 〇 See the light source clearly: X (3) The brightness is extended to the above photos, and the following judgment is made. More than 90% of the outer tube of the fluorescent lamp type LED illuminator is visible. ◎ 70~90% of the outer tube of the fluorescent lamp type LED illuminator is visible. The outer tube of the illuminating type LED illuminating lamp is visible. 50~69% is bright visible Δ 50% of the outer tube of the fluorescent lamp type LED illuminator is not visible and bright X (Example 1) PCM45 extruder made by Chibei Iron Works Co., Ltd., at a resin temperature of 250 ° C 50 parts by mass of a cyclic polyolefin resin (melt flow rate by TOPAS (TM) 6015 Topas Advanced Polymers, Inc.: 0_4 1 (23 0 ° C '2_16 kgf)) and 50 parts by mass of ethylene and octene Block copolymer resin (GFUSE (TM) D9817.15 melt flow rate: 26 (23 (TC, 2.16kgf)) melt-mixed, extruded with a τ die, cooled by a pear skin pattern The roller (Ra=〇.55) is cooled to obtain a thicker one: the: -38- 201038978 degree 4 0 0 μηη light diffusing film. The opposite surface of the above cooling roll is a mirror press roll. The characteristics of the light-diffusing film are shown in Table 1. The light-diffusing film obtained in this example is excellent in all optical properties. A light-diffusing film for illuminating devices using various light sources such as LED light sources. The color difference measured by the light resistance test is 1. 〇, and its light resistance is also excellent. (Example 2) PCM45 extruder manufactured by Chiba Iron Works Co., Ltd. 35 parts by mass of a cyclic polyolefin resin (melt flow rate by TOPAS (TM) 60 15 Topas Advanced Polymers Co., Ltd.: 0.41 (230 ° C, 2.16 kgf)) and 65 parts by mass at a resin temperature of O 250 〇c The block copolymer resin formed of ethylene and octene (INFUSE (TM) D9817.15, manufactured by Daewoo Chemical Co., Ltd., melt flow rate · 29 (230 ° C, 2.16 kgf)) was melt-mixed and extruded by a T die. The film is cooled by a mirror-finished cooling roll to obtain a light-diffusing film having a thickness of 300 μm. In the above cooling, a vacuum box is used to adhere the film to the cooling roll. The characteristics of the obtained light-diffusing film are as shown in Table 1. The light-diffusing film produced in this example has a slightly worse dot disappearance than the light-diffusing film of Example 1, but has a better brightness and is a high-quality light-diffusing film. The color difference measured by the light resistance test. It is 1.0, and its light resistance is also excellent. (Example 3) In the method of Example 2, a light-diffusing film was obtained in the same manner as in Example 2 except that the film had a thickness of 150 μm. -39- 201038978 The characteristics of the light-diffusing film obtained were as shown in Table 1. The light-diffusing film produced in this example has a slightly less brightness extension than the light-diffusing film of Example 1, but has a better brightness and is a high-quality light-diffusing film. (Example 4) In the method of Example 2, a light-diffusing film was obtained in the same manner as in Example 2 except that the thickness of the film was 200 μm. The characteristics of the obtained light-diffusing film are shown in Table 1. The light-diffusing film obtained in the present example has the same characteristics as the light-diffusing film of Example 3, and is a high-quality light-diffusing film. (Example 5) In the method of Example 1, a light-diffusing film was obtained in the same manner as in Example 2 except that the thickness of the light-diffusing film was 200 μm. The characteristics of the obtained light-diffusing film are shown in Table 1. The light-diffusing film obtained in this example has a slightly worse spread of dot disappearance and brightness than the light-diffusing film of Example 1, but has a better brightness and is a high-quality light-diffusing film. (Example 6) 35 parts by mass of a cyclic polyolefin-based resin (TOPAS (TM) 6015 Topas Advanced Polymers, manufactured by Sigma-Aldrich Co., Ltd., PCM45 extruder, melt flow rate: 0.4 1 (2 3 0 ° C, 2.1 6 kgf)) and 65 parts by mass of a random copolymer resin formed of ethylene and octene (ENGAGE (TM) 8137 melt flow rate: 30 (1 90 ° C, manufactured by Daewoo Chemical Co., Ltd.) 2.16 kgf)) melt-mixed, extruded by T-die, -40-201038978 Cooled with a mirror-finished cooling roll to obtain a light-diffusing film having a thickness of 300 μm. At the time of the above cooling, the vacuum box is used to adhere the film to the cooling roll. The characteristics of the obtained light-diffusing film are shown in Table 1. The light-diffusing film obtained in this example has the same characteristics as the light-diffusing film of Example 3, and is a high-quality light-diffusing film. (Example 7) Drying at 180 ° C for 3 hours in a vacuum dryer, and 85 parts by mass of the actual lubricant-free polyethylene terephthalate resin and 15 parts by mass were sufficiently removed. The mixture of low-density polyethylene resin (SP1540) made by Prem Polymers Co., Ltd. is fed into a single-axis extruder, melted at 280 ° C, passed through a filter and a gear pump to remove foreign matter, and the amount of extrusion is performed. After homogenization, it was extruded into a sheet shape by a T die on a cooling drum controlled at 25 °C. At this time, a metal wire electrode having a diameter of 0.1 mm was used, and static electricity was applied to adhere to the cooling drum to obtain an unstretched film. Next, in the longitudinal direction, the film was stretched 5 times in the longitudinal direction at a temperature of 103 ° C to obtain an original film of a light-diffusing film having a thickness of ΙΟΟ μηη. The diffused ratio of the original plate of the obtained light-diffusing film was Ο 2.5. In the direction in which the main diffusion direction is orthogonal, the original sheets of the two light-diffusing films are bonded by an optical adhesive to obtain a light-diffusing film. The thickness of the adhesive layer is 10 μmη. The characteristics of the obtained light-diffusing film are shown in Table 1. The light diffusing film produced in this example is a high quality light diffusing film. However, the change in chromatic aberration measured by the light resistance test was 3.7, which was slightly inferior in light resistance to the light-diffusing film of Example 1 or 2. -41 - 201038978 (Example 8) Using a PCM45 extruder manufactured by Chiba Iron Works Co., Ltd., 50 parts by mass of a fluorine-based resin (Kynar 720 (PVDF) Alcoma) melt flow rate at a resin temperature of 250 ° C: 10 (230 ° C, 5 kg f)) and 50 parts by mass of polymethylpentene resin (TPX (TM) DX820 manufactured by Mitsui Chemicals Co., Ltd., melt flow rate: 110 (260 ° C, 5 kg f)) was melt-mixed to The τ die was extruded and cooled by a mirror-finished cooling roll to obtain a master of a light-diffusing film having a thickness of 100 μm. In the above cooling, a vacuum box is used to perform a close coupling of the film and the cooling roll. Corona treatment is performed on one side. The original version of the obtained light-diffusing film had a diffusivity ratio of 1 2.7. In the direction in which the main diffusion direction is orthogonal, the original sheets of the two light-diffusing films are bonded by an optical adhesive to obtain a light-diffusing film. The thickness of the adhesive layer is 10 μmη. The characteristics of the obtained light-diffusing film are shown in Table 1. The light diffusing film produced in this example is a high quality light diffusing film. (Example 9) 0 Using a PCM45 extruder manufactured by Chiba Iron Works Co., Ltd., 50 parts by mass of a fluorine-based resin (Kynar 720 (PVDF) Alcoma melt flow rate: 10 (230 °) at a resin temperature of 250 °C C, 5 kg f)) and 50 parts by mass of a cyclic polyolefin resin (melt flow rate: 2 · 1 (2 3 0 ° C, 2.1 6 kgf) manufactured by TOPAS (TM) 6013 Topas Advanced Polymers) The film was extruded by a T die and cooled by a mirror cooling roll to obtain a master of a light diffusing film having a thickness of 70 μm. At the time of the above cooling, the vacuum box was used to adhere the film to the cooling roll. Corona treatment is performed on one side. -42- 201038978 The original version of the light diffusing film obtained has a diffusivity ratio of Π·2. In the direction in which the main diffusion direction is orthogonal, the original sheets of the two light-diffusing films are bonded by an optical adhesive to obtain a light-diffusing film. The thickness of the adhesive layer was 10 μm. The characteristics of the obtained light-diffusing film were as shown in Table 1. The light diffusing film produced in this example is a high quality light diffusing film. (Comparative Example 1) 35 parts by mass of a cyclic polyolefin resin (TOPAS (TM) 6013 Topas Advanced Polymers, manufactured by the PCM45 extruder manufactured by Chiba Iron Works Co., Ltd., melt flow Rate: 2.0 (230 ° C, 2.16 kgf)) and 65 parts by mass of a block copolymer resin formed of ethylene and octene (INFUSE(TM) D9817.15 manufactured by Daewoo Chemical Co., Ltd. Melt flow rate: 26 (230 ° C , 2.16 kgf)) melt-mixed, extruded by a T die, and cooled by a mirror-finished cooling roll to obtain a light-diffusing film having a thickness of 400 μm. At the time of the above cooling, the vacuum box is used to adhere the film to the cooling roll. The characteristics of the obtained light-diffusing film are shown in Table 1. The light-diffusing film obtained in the comparative example is better in brightness than the light-diffusing film of Example 1, but the light-diffusing anisotropy is high and the brightness is poorly expanded' from the viewpoint of having a uniform light amount. , is a poor quality light diffusion film. (Comparative Example 2) 50 parts by mass of spherical acrylic resin particles having an average particle diameter of 3 μm (Taikoki (TM) FH-S3 00, manufactured by Toyobo Co., Ltd.) and 50 parts by mass were used. The mixture of the polyurethane resin was applied to one side of a highly transparent polyester film (manufactured by Toyobo Co., Ltd. - 43-201038978 Cosmosha A4 3 00) having a thickness of 250 μm and dried to make it dry. A light diffusion film was obtained with a thickness of 25 μm. The characteristics of the obtained light-diffusing film are shown in Table 1. The light-diffusing film obtained in this comparative example was superior in light transmittance to the light-diffusing film of Example 1, but had a poor spread of dot disappearance and brightness, and was a low-quality light-diffusing film. (Comparative Example 3) A highly flake-shaped cerium oxide particle (AGC Yersley) sapphire (TM) LFSHN050 which was not mixed with a binder resin and had a thickness of nanometer diameter using a coater ), which was applied to a single side of a highly transparent polyester film (manufactured by Toyobo Co., Ltd., Cosmosha Α 4 3 00) having a thickness of 250 μm and dried to have a thickness of 30 μm after drying. Light diffusing film. The characteristics of the obtained light-diffusing film are shown in Table 1. The light-diffusing film obtained in the comparative example has the same characteristics as the light-diffusing film of Example 4 in that the dot-dissipation property and the brightness are expanded, but the total light transmittance is low and the brightness is poor, and the quality is low. Light diffusing film. Ο (Comparative Example 4) 50 parts by mass of a cyclic polyolefin resin (TOPAS(TM) 6015 T 〇pas A dvanced Ρ ο 1 ymers) was used at a resin temperature of 250 ° C using a PCM45 extruder manufactured by Chiba Iron Works Co., Ltd. Company system, melt flow rate: 0.41 (2301:, 2.16kg f)) and 50 parts by mass of block copolymer resin formed of ethylene and octene (INFUSE(TM) D9 100.05, manufactured by Daiwa Chemical Co., Ltd., melt flow rate : 2.1 (230 ° C, 2.16 kgf)) melt-mixed, extruded with a T-die 'cooled with a mirror-finished cooling roll to obtain a light-diffusing thin film of thickness 175 μηι-44 - 201038978. At the time of the above cooling, the vacuum film was used to adhere the film to the cooling roll. The characteristics of the obtained light-diffusing film are shown in Table 1. The light-diffusing film obtained in this comparative example has a high parallel light transmittance and a high diffusion ratio, and has poor dot-disappearance and brightness expansion, and is a low-quality light-diffusing film. (Comparative Example 5) 35 parts by mass of a cyclic polyolefin resin (T〇PAS(TM) 6013 〇Topas Advanced Polymers Co., Ltd.) was used at a resin temperature of 250 ° C using a PCM45 extruder manufactured by Chiba Iron Works Co., Ltd. , melt flow rate: 2.1 (230 ° C)) and 65 parts by mass of a block copolymer resin formed of ethylene and octene (fabric flow rate of INFUSE (TM) D9817.15 manufactured by Daewoo Chemical Co., Ltd.: 26 (230 t)) The mixture was melt-mixed, pressed with a T die, and cooled by a mirror-finished cooling roll to obtain a light-diffusing film having a thickness of 175 μm. In the above cooling, a vacuum box is used to adhere the film to the cooling roll. The characteristics of the obtained light-diffusing film are shown in Table 1. The light-diffusing film obtained in this comparative example has a high parallel light transmittance and a high spread undulation ratio, and has a poor spread of dot disappearance and brightness, and is a low-quality light-diffusing film. (Comparative Example 6) A light-diffusing film formed of a polycarbonate resin having an embossed surface was subjected to property evaluation. The results are shown in Table 1. The light-diffusing film obtained in this comparative example has a high parallel light transmittance and a high diffusivity ratio, and has a spread of dot disappearance and brightness, and is a low-45-201038978 quality light-diffusing film. Moreover, the change in color difference is as high as 9.5, and the light resistance is poor. [Production of Light-Diffusing Film Laminate Sheet] (Example 10) The light-diffusing film obtained in Examples 1 to 6 and a transparent polyester film having a thickness of 250 μm and a total light transmittance of 92% (Coomamo, manufactured by Toyobo Co., Ltd.) Xiain Α 43 00), adhered with an optical double-sided adhesive sheet to form a light-diffusing film laminate. ¢) The enamel-laminated sheets each have the same optical characteristics as the respective light-diffusing films, and are high-quality light-diffusing materials. Further, the obtained light-diffusing film laminate sheets have better non-optical properties such as heat resistance and strength than the light-diffusing films of Examples 1 to 6. (Example Π) In the method of Example 1, a polycarbonate sheet having a thickness of 200 μm and a total light transmittance of 88% which was surface-treated with a polyurethane-based tackifying coating agent was passed through a pressure roller. The side ' thereby producing a 扩散^ light-diffusing film laminated sheet formed by laminating polycarbonate sheets. The light-diffusing film laminated sheet obtained in the present example has optical characteristics equivalent to those of the light-diffusing film of Example 1, and is high in quality when used as a light-diffusing material for an illumination device using various light sources such as LEDs. Further, the light-diffusing film ' of Comparative Example 1 has better non-optical properties such as heat resistance and strength. (Example 12) Using a 40W white light transparent shade type fluorescent lamp type LED illumination lamp (MLT-40KC) manufactured by Maurice, the light diffusion of Example 1 of -46 - 201038978 was carried out with optical double-sided tape. The film and the light-diffusing film laminate of Example 8 were adhered to the surface of the transparent cover. It is possible to present a uniform and stable illumination of light that illuminates the entire outer tube and does not see the point of the LED source. (Comparative Example 7) In the example 12, when the light-diffusing film of the device of Comparative Example 2 was replaced, the light diffusibility was lowered, the light could not be spread over the entire outer tube, and the point of the LED light source was clearly seen. (Example 13) 〇 Using a two-stage melt extruder, 35 parts by mass of a cyclic polyolefin resin (T〇PAS(TM) 6013S-04 Topas Advanced Polymers Co., Ltd., melted in the first extruder' Flow rate: 2.0 (230 ° C, 2.16 kg f)) and 65 parts by mass of a block copolymer resin formed of ethylene and octene (INFUSE(TM) D9817.15 by Dawu Chemical Co., Ltd. Melt flow rate: 26 (230 °C, 2.16kg f)) as a light diffusion layer, in the second extruder, polypropylene-based adhesive resin (Adam (TM) QF551 Mitsui Chemicals Co., Ltd., melt flow rate: 5-7 (190 ° C ' 2_16kgf)) is a two-layer layer (heat-sealing layer), which is melt-co-extruded by a T-die method and then cooled by a mirror-finished cooling roll to obtain a two-sided system having a total thickness of 400 μm, which is laminated with a heat-adhesive layer. A light diffusing film. The adhesion of the film to the cooling roll at the time of the above cooling was carried out in the same manner as in Example 1. Eye stains do not occur even if the film is continuously formed for a long time. The obtained light-diffusing film had the same optical characteristics as in Example 1 and was excellent in thermal adhesiveness, and the dimensional stability of the light-diffusing film was improved by heat bonding to the substrate. -47- 201038978 Thermal adhesion and dimensional stability were evaluated by the following methods. Either one is awkward. <Hot Adhesiveness> A smooth and transparent acrylic plate having a thickness of 3 mm (manufactured by Mitsubishi Rayon Co., Ltd.: Acrylic) was placed on a fixing table of a hot press, and placed on the acrylic plate. Further, the test piece was further covered with a ruthenium rubber sheet having a thickness of 3 mm (hardness HsA50°), and pressed at a surface temperature of 180 ° C, and pressed on the above-mentioned ruthenium rubber sheet to 49 N/ The pressure of cm2 is pressed for 30 seconds. After heating and pressure-bonding, it was left to stand at a temperature of 23 ° C and a relative humidity of 65% for 30 minutes, and when it was peeled off at a speed of 300 deg/min using UTC-III L manufactured by Toyo Seiki Co., Ltd. The resistance is the adhesion. The determination of the adhesion is performed on the basis of the following criteria.
密合力爲0.1N/15mm以上：〇 密合力係低於0.1N/15mm : X <尺寸安定性> ^ 依據上述熱黏合性評價法’將光擴散薄膜熱黏合於丙 烯酸板之試驗品，在調溫於8 0 °C的烘箱中，靜置240小時， 加溫處理後’測定光擴散薄膜的縱及橫方向之尺寸安定 性，與加溫處理前的個別尺寸進行比較，以下述之基準來 判定。 由加溫處理而來的尺寸變化，無論於任—方向，皆低 於0· 1 %者：〇 由加溫處理而來的尺寸變化，至少於任一方爲0. i %以 -48- 201038978 上者：χ (實例14) 實例13的方法中，將第2擠壓機的擠壓樹脂改爲聚丙 烯系的黏合性樹脂（阿杜瑪（TM)QF551三井化學公司製 熔融流動率：5.7(190°C))，並使用聚丙烯系樹脂 FS2011DG3(住友化學公司製，住友諾普蘭（TM))以外，以 和實例13相同之方法而製得光擴散薄膜。 製得的光擴散薄膜，其光擴散特性優異，即使長時間 〇 連續地製膜，亦不發生眼垢。惟，相較於實例1 3所製得的 光擴散薄膜，其熱黏合較差。 (實例15〜18) 使用實例1、5、7及18製得的各個光擴散薄膜，以下 述方法來測定使用於液晶顯示裝置用逆光裝置時之正面亮 度、亮度依賴性及圖形掩蔽性。結果如第2表所示。 無論任一實例所製得的光擴散薄膜，皆具有如各個實 例中敘述之優異特性，且具有高的光的變曲度，藉由使用 Θ —片的光擴散薄膜，即具有高的正面亮度，且亮度的角度 依賴性少，更具有優異的圖形掩蔽性，係高品質的提升液 晶顯示裝置用逆光裝置的亮度之零件。 <使用於液晶顯示裝置用逆光裝置時之正面亮度> 分別裝設3根冷陰極管於長徑側（橫方向）的兩側之1 9英吋 的導光板型（使用白色反射薄膜的網眼型）之逆光組件的射出光 側的丙烯酸板上，將40mmx60mm角（60mm側爲横方向）的評價 試驗品裝設（重疊而裝設，試驗品因捲邊等而露出時，以膠帶來 -49- 201038978 固定其四角）於幾近其中央部位’裝設已切下30mm><50mm 角（5 0mm側爲橫方向）之黑色遮光紙’使切下部位的中心係 評價試驗品的中心部位’於暗室測定亮度。黑色的遮光紙 係覆蓋整體逆光組件之尺寸而固定’不露出光而測定。逆 光組件係水平地裝設而測定。 此亮度係使用脫普康技術股份公司製的脫普康分光放 射計SR-3A，以測定角度2度，在與逆光組件表面的距離 爲40cm，而評價用試驗品的中心在正下方之位置進行測 〇 定。 本測定中，評價用試驗品係裝設於主擴散方向與冷陰 極管的長方向成垂直之方向而測定。 <使用於液晶顯示裝置用逆光裝置時的亮度之角度依賴性> 除了將脫普康分光放射計SR - 3A裝設在使脫普康分 光放射計SR — 3 A與評價用試驗品的中心之角度係3 5度傾 斜於相對於逆光組件的表面之垂線的位置之外，以和上述 正面亮度相同之方法來測定亮度。以上述正面亮度除以此 ^ 亮度之値係角度依賴性。此値愈大，亮度的角度依賴性愈 優異。1. 〇最佳" <使用於液晶顯示裝置用逆光裝置時之圖形掩蔽性> 在上述正面亮度的測定中，於亮著逆光之狀態，以肉 眼觀察開口部位，並進行下述之判定。 完全看不見導光板的網眼時：〇 稍微地看見導光板的網眼時：△The adhesion is 0.1 N/15 mm or more: the 〇 adhesion is less than 0.1 N/15 mm: X < dimensional stability> ^ According to the above thermal adhesion evaluation method, the light diffusion film is thermally bonded to the test piece of the acrylic plate, In an oven adjusted to 80 ° C, it was allowed to stand for 240 hours. After the heating treatment, the dimensional stability of the light-diffusing film in the longitudinal and transverse directions was measured, and compared with the individual dimensions before the heating treatment, the following Benchmark to determine. The dimensional change caused by the warming treatment, regardless of the direction of the direction, is less than 0.1%. The dimensional change caused by the heating process is at least 0. i% to -48- 201038978 The above method: χ (Example 14) In the method of Example 13, the extrusion resin of the second extruder was changed to a polypropylene-based adhesive resin (Alumina (TM) QF551 Mitsui Chemicals Co., Ltd. melt flow rate: 5.7 (190 ° C)) A light-diffusing film was obtained in the same manner as in Example 13 except that polypropylene resin FS2011DG3 (manufactured by Sumitomo Chemical Co., Ltd., Sumitomo Nopland (TM)) was used. The obtained light-diffusing film is excellent in light-diffusing properties, and does not cause eye stains even if it is continuously formed over a long period of time. However, compared to the light-diffusing film prepared in Example 13, the thermal adhesion was poor. (Examples 15 to 18) Using the respective light-diffusing films obtained in Examples 1, 5, 7, and 18, the front luminance, the luminance dependency, and the pattern concealing property when used in a backlight for a liquid crystal display device were measured by the following methods. The results are shown in Table 2. The light-diffusing film produced by any of the examples has excellent characteristics as described in the respective examples, and has a high degree of light curvature, and has a high front luminance by using a light diffusion film of a sheet. Moreover, the angle dependence of brightness is small, and the image masking property is excellent, and it is a part which improves the brightness of the backlight of the liquid crystal display device with high quality. <Front Brightness When Used in Backlighting Device for Liquid Crystal Display Device> Each of the three cold cathode tubes is provided with a light guide plate type of 9 吋 on both sides of the long diameter side (lateral direction) (using a white reflective film) In the acrylic plate on the light-emitting side of the backlight unit of the mesh type, an evaluation test piece having an angle of 40 mm x 60 mm (horizontal direction on the 60 mm side) is mounted (overlapped, and the test piece is exposed by curling or the like, and tape is used. -49- 201038978 Fixing the four corners) The black shading paper that has been cut 30mm><50mm angle (the 50mm side is the horizontal direction) is placed near the center of the area. The central part 'measures brightness in the dark room. The black shading paper was measured to cover the size of the entire backlight assembly and was fixed 'not exposed to light. The retroreflective elements were measured horizontally and mounted. This brightness was measured using a Depotcon Spectroradiometer SR-3A manufactured by O&P Technology Co., Ltd. to measure an angle of 2 degrees, and the distance from the surface of the backlight unit was 40 cm, and the center of the evaluation test product was directly below. Make measurements. In this measurement, the evaluation test product was mounted in a direction in which the main diffusion direction was perpendicular to the longitudinal direction of the cold cathode tube. <Angle dependence of brightness when used in a backlight unit for a liquid crystal display device> In addition to mounting the Opulcon spectroradiometer SR-3A on the sample material for evaluation and test of the Opulcon spectroradiometer SR-3A The angle of the center is measured by the same method as the above-described front luminance, except that the angle of 35 degrees is inclined to the position perpendicular to the surface of the backlight unit. The above-mentioned front luminance is divided by the angle dependence of the luminance of the ^ luminance. The larger the 値, the better the angular dependence of brightness. 1. 〇Best "<Graphic masking property when used in a backlight device for a liquid crystal display device> In the measurement of the front luminance, the opening portion is visually observed in a state of backlighting, and the following is performed. determination. When the mesh of the light guide plate is completely invisible: 时 When the mesh of the light guide plate is slightly seen: △
清楚地看見導光扳的網眼時：X -50- 201038978 (比較例8) ’ 使用比較例4所製得的光擴散薄膜，以和實例1 5 ~ 1 8 相同之方法，測定當使用於液晶顯示裝置用逆光裝置時之 正面亮度、亮度的角度依賴性及圖形掩蔽性。結果如第2 表所示。 本比較例所製得的光擴散薄膜，其圖形掩蔽性差。 (比較例9) 使用市售的微透鏡薄膜，以和實例15〜18相同之方 〇 法，測定當使用於液晶顯示裝置用逆光裝置時之正面亮 度、亮度的角度依賴性及圖形掩蔽性。結果如第2表所示。 此微透鏡雖具有高的正面亮度，惟亮度的角度依賴性 差。且，僅使用一片的此微透鏡時，圖形掩蔽性亦差。 (比較例1〇) 使用一種用於市售的逆光裝置且以圓珠塗層法而製造 之光擴散薄膜，以和實例1 1 8相同之方法，測定當使用 於液晶顯示裝置用逆光裝置時之正面亮度、亮度的角度依 Ο 賴性及圖形掩蔽性。結果如第2表所示。 僅使用一片的此光擴散薄膜時，亮度的角度依賴性及 圖形掩蔽性差。 (比較例11) 用於正面亮度及亮度的角度依賴性的測定之逆光組件 中，所組入的上擴散薄膜/稜鏡透鏡薄膜/下擴散薄膜而形 成之光學薄膜套組，使用此套組，以和實例1 1及1 2相同 之方法’測定當使用於液晶顯示裝置用逆光裝置時之正面 -51- 201038978 亮度、亮度的角度依賴性及圖形掩蔽性。結果如第2表所 7p\ ° 此薄膜套組雖正面亮度及圖形掩蔽性優異，惟亮度的 角度依賴性差。且因片數多，亦不利於經濟性。 (實例19及20) 實例1及5之光擴散薄膜，係以下述方法來測定當使 用於液晶顯示裝置用逆光裝置時之內面亮度均勻性。結果 如第3表所示。 〇 無論任一實例之光擴散薄膜，其平均亮度皆高，且內 面亮度均勻性亦高，係高品質的逆光裝置用之光擴散薄膜。 <使用於液晶顯示裝置用逆光裝置時之內面亮度均勻性> 將20英吋且裝設12根冷陰極管之正下方式的逆光組 件之光擴散丙烯酸板更換成透明丙烯酸板，將A-4尺寸的 試驗品放置在此透明丙烯酸板上幾近中央部位處，以膠帶 來固定4個角，使用海蘭特公司製的高機能亮度&色度計 測系統（RISA)，於暗室以點亮逆光組件之狀態，測定試驗 0 品的中央部位於100x220頂盒的面積之亮度。亮度係測定 最大亮度、最小亮度、亮度。內面亮度均勻性係以上述方 法中求得的最小亮度/最大亮度之比來表示。此値愈小，則 亮度斑愈小。 上述冷陰極管係裝設成使冷陰極管的長方向即爲逆光 組件的長方向（橫方向）而使用。亮度測定裝置係裝設於試 驗品的幾近中心部位的正上方，且透明丙烯酸板表面與亮 度計射入光面的距離爲1 2 0 c m之位置而測定。 -52- .201038978 逆光組件係裝設於水平而測定。 本測定中，評價用試驗品係裝設於主擴散方向與冷陰 極管的長方向成垂直之方向而測定。 (比較例12) 不裝設光擴散薄膜而測定內面亮度均勻性。結果如第 3表所示。 最大亮度係顯著地提高，且內面亮度均勻性亦明顯地 增大。表示上述實例之薄膜具有大的光學特性控制效果。 Ο (比較例13〜15) 分別使用於比較例8〜10之光擴散薄膜，係進行內面亮 度均勻性之測定。結果如第3表所示。 使用於比較例8之光擴散薄膜，雖具有高的最大亮 度，惟內面亮度均勻性低，僅一片的光擴散薄膜，則性能 不足。 使用於比較例9和10之薄膜，相較於上述實例之光擴 散薄膜，其最大亮度雖明顯地提高，惟內面亮度均勻性低， Ο 僅一片的光擴散薄膜，則性能不足。 (比較例16) 更換爲逆光裝置用光擴散薄膜，用於內面亮度均勻性 測定之逆光組件中，所組入的上擴散薄膜/稜鏡透鏡薄膜/ 下擴散薄膜而形成之光學薄膜套組，測定其內面亮度均勻 性。結果如第3表所示。 最大亮度雖高’惟內面亮度均勻性差。且薄膜的片數 多，不利於經濟性。 -53- 201038978 οο (撇I濉) 明亮度 之擴展 ◎ ◎ 〇 〇 〇 〇 〇 〇 ◎ X X 〇 X X X 11 ◎ 〇 〇 〇 〇 〇 〇 〇 ◎ ◎ X 〇 X X X 明亮度 〇 ◎ ◎ ◎ ◎ ◎ 〇 ◎ 〇 〇 ◎ X ◎ 〇 ◎ 表面粗糙度比 (RaH/RaL) 〇 o 〇 y—t 〇 vn rn T-^ o o r"H 寸 ΓΟ o (N o 擴散度比 (DH/DL) in <η V-H cn p o i-H 'T^ 1-H 卜 cs o l—H q —— m <ri (N q Q Os 卜 CO vn m vo CN 00 <N (N i〇 m fN 00 X Q cn 00 cn Ό r^i to CN yn ?: 寸 m 00 OS 00 Cn| (N o 00 霧度 (%) CN cK o v£> 00 On 00 Os 00 oo Q\ in 00 ON 寸 od ON 〇i OS t-H s； o cK σ\ q οί (N i〇 ON o irl OS m Os ΓΟ § 平行光線透 過率(％) ό o (N r-H CN »—H 00 oo r-H 00 o On rn o T—l o 00 τ·~Η o cn 卜 od m ^ 鹱S o o 寸 vd 00 VO rsi o (N vq T*~< 00 CN 〇\ o cn i o od in to g o o in oo cn d as 實例1 實例2 實例3 實例4 ί 實例5 實例6 實例7 實例8 實例9 比較例1 比較例2 比較例3 比較例4 比較例5 比較例6 -寸w-1- 201038978When the mesh of the light guide plate is clearly seen: X -50- 201038978 (Comparative Example 8) ' Using the light diffusing film prepared in Comparative Example 4, the same method as in Examples 15 to 18 is used for the measurement when used. The front luminance, the angular dependence of the luminance, and the pattern concealing property of the backlight device for a liquid crystal display device. The results are shown in Table 2. The light-diffusing film obtained in this comparative example had poor pattern masking property. (Comparative Example 9) Using a commercially available microlens film, the front side brightness, the angular dependence of the brightness, and the pattern concealing property when used in a backlight unit for a liquid crystal display device were measured in the same manner as in Examples 15 to 18. The results are shown in Table 2. Although this microlens has a high front luminance, the angular dependence of luminance is poor. Moreover, when only one of the microlenses is used, the pattern masking property is also poor. (Comparative Example 1) Using a light-diffusing film manufactured by a bead coating method using a commercially available backlight device, the same method as in Example 1 18 was used to measure when used in a backlight for a liquid crystal display device. The front brightness and brightness are dependent on the image and the masking property. The results are shown in Table 2. When only one of the light diffusing films is used, the angular dependence of the brightness and the pattern masking property are inferior. (Comparative Example 11) The optical film set formed by the upper diffusing film/稜鏡 lens film/lower diffusing film incorporated in the backlight assembly for measuring the angle dependence of front luminance and brightness, using this set In the same manner as in Examples 1 1 and 1 2, the front side of the backlight device for liquid crystal display device was measured - 51 - 201038978, and the angle dependence of brightness and brightness and the pattern masking property were measured. The result is as shown in Table 2, 7p\°. This film set is excellent in frontal brightness and pattern masking, but the angle dependence of brightness is poor. And because of the large number of films, it is not conducive to economics. (Examples 19 and 20) The light-diffusing films of Examples 1 and 5 were measured for the uniformity of the inner surface brightness when used in a backlight for a liquid crystal display device by the following method. The results are shown in Table 3. 〇 The light diffusing film of any of the examples has a high average brightness and a high uniformity of internal brightness, and is a light diffusing film for high-quality backlights. <Inner surface brightness uniformity when used in a backlight device for a liquid crystal display device> A light-diffusing acrylic plate of a backlight unit of 20 inches and equipped with 12 cold cathode tubes is replaced with a transparent acrylic plate. The test piece of A-4 size was placed at the center of the transparent acrylic plate, and four corners were fixed with tape. The high-performance brightness & colorimetric measurement system (RISA) manufactured by Hailant was used in the dark room. In the state in which the backlight unit is illuminated, the brightness of the area of the center portion of the test product located at 100 x 220 top boxes is measured. Brightness is measured by maximum brightness, minimum brightness, and brightness. The inner surface brightness uniformity is expressed by the ratio of the minimum brightness/maximum brightness obtained in the above method. The smaller the flaw, the smaller the brightness spot. The cold cathode tube is installed such that the long direction of the cold cathode tube is the longitudinal direction (lateral direction) of the backlight unit. The brightness measuring device was mounted directly above the center portion of the test piece, and the surface of the transparent acrylic plate was measured at a distance of 1 2 0 c m from the light incident surface of the light meter. -52- .201038978 The backlight assembly is measured at the level. In this measurement, the evaluation test product was mounted in a direction in which the main diffusion direction was perpendicular to the longitudinal direction of the cold cathode tube. (Comparative Example 12) The inner surface brightness uniformity was measured without installing a light diffusion film. The results are shown in Table 3. The maximum brightness is significantly improved, and the brightness uniformity of the inner surface is also significantly increased. The film showing the above example has a large optical property control effect. Ο (Comparative Examples 13 to 15) The light-diffusing films of Comparative Examples 8 to 10 were used to measure the uniformity of the inner surface brightness. The results are shown in Table 3. The light-diffusing film used in Comparative Example 8 had a high maximum brightness, but the inner surface brightness uniformity was low, and only one piece of the light-diffusing film had insufficient performance. The films used in Comparative Examples 9 and 10 exhibited a markedly higher maximum brightness than the above-mentioned examples of the light-diffusing film, but the inner surface brightness uniformity was low, and only one piece of the light-diffusing film was insufficient in performance. (Comparative Example 16) An optical film set formed by replacing an upper diffusing film/稜鏡 lens film/lower diffusing film into a backlight assembly for measuring the uniformity of brightness of the inner surface by replacing the light diffusing film for a backlight unit , the brightness uniformity of the inner surface was measured. The results are shown in Table 3. The maximum brightness is high, but the brightness of the inner surface is poor. Moreover, the number of films is large, which is not economical. -53- 201038978 οο (撇I濉) Extension of brightness ◎ ◎ 〇〇〇〇〇〇 ◎ XX 〇 XXX 11 ◎ 〇〇〇〇〇〇〇 ◎ ◎ X 〇 XXX Brightness 〇 ◎ ◎ ◎ ◎ ◎ 〇 ◎ 〇〇◎ X ◎ 〇◎ Surface roughness ratio (RaH/RaL) 〇o 〇y—t 〇vn rn T-^ oo r"H inch ΓΟ o (N o diffusion ratio (DH/DL) in <η VH cn po iH 'T^ 1-H 卜 cs ol—H q —— m < ri (N q Q Os 卜 CO vn m vo CN 00 <N (N i〇m fN 00 XQ cn 00 cn Ό r ^i to CN yn ?: inch m 00 OS 00 Cn| (N o 00 haze (%) CN cK ov£> 00 On 00 Os 00 oo Q\ in 00 ON inch od ON 〇i OS tH s; o cK σ\ q οί (N i〇ON o irl OS m Os ΓΟ § Parallel light transmittance (%) ό o (N rH CN »—H 00 oo rH 00 o On rn o T-lo 00 τ·~Η o Cn od m ^ 鹱S oo inch vd 00 VO rsi o (N vq T*~< 00 CN 〇\ o cn io od in to goo in oo cn d as instance 1 instance 2 instance 3 instance 4 ί instance 5 instance 6 Example 7 Example 8 Example 9 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 - inch w-1- 201038978
圖形掩 蔽性 〇 〇 〇 〇 < X < 〇 亮度的角度 依賴性* »-Η 0.76 00 0.45 35度亮度 (Cd/m2) 1410 _1 1410 1340 1400 1480 1 1350 1300 〇 正面亮度 (Cd/m2) 1410 1412 1350 ι_ 1 1400 1480 1770 1620 1650 變曲度 Ο Ον 〇 (N 1 擴散度比 (DH/DL) CS ΙΟ CO ΓΟ 1 Q ο ON v〇 1 Q 00 v〇 00 〇 r—H 1 霧度 (%) 98.5 97.5 97.1 94.3 94.4 os 1 平行光線透 過率(％) ν〇 ο (Ν 00 卜 VO yn 卜 m 1 全光線透 mm%) ο 81.6 67.7 00 85.3 60.9 60.5 1 實例15 實例16 實例17 實例18 比較例8 比較例9 比較例10 比較例11 v〇 201038978 οο (嗽e濉) If 廣i 0.94 0.84 0.13 0.78 c5 0.47 0.75 平均亮度 (Cd/m2) 6897 6510 4878 6773 8497 7254 11167 最小亮度 (Cd/m2) 6604 5889 1873 5990 6198 4940 9428 最大亮度 (Cd/m2) 7094 7040 14489 7690 12382 1 ；10583 1 12529 使用光擴散薄膜 實例1 實例5 無光擴散薄膜 比較例8 比較例9 比較例10 經i 糊魃 實例19 實例20 比較例12 比較例13 比較例14 比較例15 比較例16 -9ς- 201038978 應用於產業之可能性 本發明的光擴散薄膜及其積層片，係光的透過度和擴 散度二種特性均優異之光擴散薄膜，特別是因直進光的透 過率小，例如用於採用LED光源的照明裝置時，除了使直 進性強的LED光源之光擴散成大面積，且不看見強光的光 源點之外，更進一步，因已抑制其光線的透過率度之降低 度，即使每單位面積的LED光源數減少，仍可具有均勻且 高之光量。因此，具有可抑制LED光源的光因直進性高而 Ο 引起僅可於點狀的狹窄範圍明亮，即所謂採用LED光源的 照明裝置之缺點，且可維持省能源之LED光源的特徵之優 點。 相較於先前既知的光擴散薄膜，因大幅地改善擴散 性，例如使用於以螢光燈爲光源之照明裝置時，即使縮短 螢光燈與光擴散薄膜或與光擴散薄膜積層片之距離，仍具 有高度的光擴散性，因此，具有減少照明裝置的厚度或減 少螢光燈的數目之效果。又，例如使用爲液晶顯示器等顯 Ο 示裝置之光擴散薄膜時，可減少顯示面板之厚度，且可減 少一種爲提升亮度而使用的亮度提升薄膜或光擴散薄膜等 光學機能調整用薄膜之數目。 本發明之光擴散薄膜及使用此之積層片，除維持上述 的光學特性之外，例如可提升耐熱性等非光學特性。 因此’可有效地使用於室內照明、內照式電子面板之 照明、影印機之光照射或液晶顯示器等顯示裝置之照明等 各種照明。 -57- 201038978 又’本發明的光擴散薄膜及使用之積層片，係使用爲 逆光裝置之光學零件時，因僅使用一片，即可附予高亮度、 亮度的角度依賴性之降低、內面亮度均勻性及圖形掩蔽性 等逆光裝置用的光學材料所需具備之光學特性，故可提高 逆光裝置之經濟性。特別是附予一大優點，亦即可不使用 高價的透鏡薄膜’且解決當斜角觀看時所發生的亮度降低 等使用透鏡薄膜之課題。 本發明的逆光裝置，因具有與使用透鏡薄膜的逆光裝 Ο 置相近的高度之正面亮度，且降低亮度的角度依賴性即使 用透鏡薄膜的逆光裝置之課題，故具有抑制當使用於大型 電視時，因斜角觀看而引起的畫面的明亮度之降低之優點。 因此特點，可有效地使用爲例如汽車導航般，大多從 斜角觀看的顯示器之逆光裝置。 若使用於室內或車內照明用燈具的逆光裝置時，相較 於使用透鏡薄膜的逆光裝置，具有於廣範圍呈一致的照度 之優點。 〇 又，本發明的逆光裝置，因僅使用一片的零件，即可 具備上述所有的特性，故具有高經濟性之優點。 因此，本發明的逆光裝置，可有效地使用於液晶顯# ，裝置、室內照明、內照式電子面板等。 依據本發明的光擴散薄膜之製法，可符合經濟且安$ 地製造具有上述特性的本發明之光擴散薄膜。 因此，對產業界的貢獻大。 -58- 201038978 【圊式簡單說明】 第1圖係擴散度計算方法之輔助圖。 第2圖係變曲度計算方法之輔助圖。 【主要元件符號說明】 〇Graphic masking 〇〇〇〇 < X < 角度 Angle dependence of brightness * »-Η 0.76 00 0.45 35 degree brightness (Cd/m2) 1410 _1 1410 1340 1400 1480 1 1350 1300 〇 Front brightness (Cd/m2) 1410 1412 1350 1 1 1 1 1 1 1 1 1 1 1 1 1 1 (%) 98.5 97.5 97.1 94.3 94.4 os 1 Parallel light transmittance (%) ν〇ο (Ν 00 卜 VO yn 卜 m 1 full light penetration mm%) ο 81.6 67.7 00 85.3 60.9 60.5 1 Example 15 Example 16 Example 17 Example 18 Comparative Example 8 Comparative Example 9 Comparative Example 10 Comparative Example 11 v〇201038978 οο (嗽e濉) If 广i 0.94 0.84 0.13 0.78 c5 0.47 0.75 Average brightness (Cd/m2) 6897 6510 4878 6773 8497 7254 11167 Minimum brightness (Cd /m2) 6604 5889 1873 5990 6198 4940 9428 Maximum brightness (Cd/m2) 7094 7040 14489 7690 12382 1 ; 10583 1 12529 Example of using light diffusing film 1 Example 5 Light diffusing film Comparative example 8 Comparative example 9 Comparative example 10 Paste Example 19 Example 20 Comparative Example 12 Comparative Example 13 Comparative Example 14 Comparative Example 15 Comparative Example 16 -9ς- 201038978 Application to the Industry The light-diffusing film of the present invention and the laminated sheet thereof are light-diffusing films excellent in both light transmittance and diffusivity. It is because the transmittance of the straight-through light is small. For example, when it is used for an illumination device using an LED light source, in addition to diffusing the light of the direct-intensity LED light source into a large area and not seeing the light source of the strong light, further The degree of decrease in the transmittance of the light has been suppressed, and even if the number of LED light sources per unit area is reduced, the light amount can be uniform and high. Therefore, the light having the LED light source can be suppressed from being highly straightforward and can only be caused by The point-like narrow range is bright, that is, the disadvantage of the so-called illumination device using the LED light source, and the advantages of the characteristics of the energy-saving LED light source can be maintained. Compared with the previously known light diffusing film, when the diffusing property is greatly improved, for example, when used in a lighting device using a fluorescent lamp as a light source, even if the distance between the fluorescent lamp and the light diffusing film or the light diffusing film laminated sheet is shortened, It still has a high degree of light diffusivity and, therefore, has the effect of reducing the thickness of the illumination device or reducing the number of fluorescent lamps. Further, for example, when a light-diffusing film which is a display device such as a liquid crystal display is used, the thickness of the display panel can be reduced, and the number of optical function adjusting films such as a brightness enhancement film or a light diffusion film used for improving the brightness can be reduced. . The light-diffusing film of the present invention and the laminated sheet using the same can maintain non-optical properties such as heat resistance, in addition to maintaining the above optical characteristics. Therefore, it can be effectively used for various illuminations such as indoor illumination, illumination of an internal illumination type electronic panel, light irradiation of a photocopier, or illumination of a display device such as a liquid crystal display. -57- 201038978 In addition, when the optical diffusing film of the present invention and the laminated sheet to be used are optical components which are backlighting devices, high brightness and brightness are reduced in angle dependence by using only one sheet. The optical characteristics required for the optical material for the backlight unit such as brightness uniformity and pattern masking property can improve the economic efficiency of the backlight unit. In particular, it is advantageous to use a lens film which does not use a high-priced lens film, and to solve the problem of using a lens film such as a decrease in brightness which occurs when viewing at an oblique angle. The backlight unit of the present invention has a front luminance of a height close to that of a backlight unit using a lens film, and reduces the angular dependence of luminance, that is, a backlight device using a lens film. Therefore, it is suppressed when used in a large-sized television. The advantage of reducing the brightness of the picture caused by the oblique angle viewing. Therefore, it is possible to effectively use a backlight of a display which is mostly viewed from an oblique angle, such as a car navigation. When used in a backlight of an indoor or interior lighting fixture, it has an advantage of uniform illumination over a wide range compared to a backlight using a lens film. Further, since the backlight unit of the present invention has all of the above characteristics by using only one piece of the member, it has an advantage of high economic efficiency. Therefore, the backlight device of the present invention can be effectively used for liquid crystal display, devices, indoor illumination, internal illumination type electronic panels, and the like. According to the method for producing a light-diffusing film of the present invention, the light-diffusing film of the present invention having the above characteristics can be produced economically and economically. Therefore, the contribution to the industry is great. -58- 201038978 [Simple description of the 圊 type] Figure 1 is an auxiliary diagram of the calculation method of the diffusion degree. Figure 2 is an auxiliary diagram of the calculation method of the degree of curvature. [Main component symbol description] 〇
-59--59-