JP4428676B2 - Scattering elliptical polarizing plate and liquid crystal display device - Google Patents

Description

【００１５】
上記において広域型１／４波長板の形成に際しては耐熱性に優れ、正面と斜視で位相差特性が相違しにくいものを得る点などより、延伸フィルムの少なくとも１枚に波長６３３nmの光に対する光弾性係数が５０×１０^−１３cm^２／dyn以下、複屈折率差△ｎ1、△ｎ2の波長依存性が４００nm（△ｎ1）と５５０nm（△ｎ2）の波長光に基づいて△ｎ1／△ｎ2＜１．０５であるものを用いることが好ましい。これにより裏面の反射層を介した透過反射光における正面（垂直）と斜め方向での位相差特性の相違に基づいて生じる、正面方向での黒い均一な反射色が視角を変えた斜視により例えばやや明るい青色や淡黄色へと変化する現象などを防止ないし抑制することができる。
【００１６】
前記の光弾性係数と複屈折率差の波長依存性の容易な実現性などの点よりは、延伸フィルムを形成するポリマーとして、ポリオレフィン系、就中、環状オレフィン系や酢酸セルロース系、ポリメチルメタクリレート系のものなどが好ましく用いうる。またかかるポリマーは、１／４波長の位相差を与える延伸フィルムの形成に特に好ましく用いることができる。さらに前記した光弾性係数や複屈折率差の波長依存性を満足する延伸フィルムは、正面・斜視間の色変化の抑制などの点より単層系の１／４波長板としても好ましく用いうる。
【００１７】
一方、１／２波長の位相差を与える延伸フィルムの形成には、就中その位相差付与の加工性や高い光弾性係数の付与及び４００nm（△ｎ1）と５５０nm（△ｎ2）の波長光に基づいて複屈折率差△ｎ1、△ｎ2の波長依存性が△ｎ1／△ｎ2＞１．０５を満足する特性の付与による正面と斜視での位相差の相違の抑制、ひいては視角特性の向上などの点より、例えばポリカーボネート系やポリスルホン系、ポリエーテルスルホン系やポリアリレート系などのポリマーが特に好ましく用いうる。
【００１８】
従って前記した如く耐熱性や視角特性などに優れる広域型１／４波長板を得る点よりは、波長６３３nmの光に対する光弾性係数５０×１０^−１３cm^２／dyn以下で△ｎ1／△ｎ2＜１．０５を満足する単色光に対して１／４波長の位相差を与える延伸フィルムと、△ｎ1／△ｎ2＞１．０５を満足する単色光に対して１／２波長の位相差を与える延伸フィルムとの組合せとすることが好ましい。なお前記の光弾性係数や△ｎ1／△ｎ2を満足する延伸フィルムは、形成材料の種類や延伸条件等を制御することにより得ることができる。耐熱性の向上等の点より波長６３３nmの光に対する光弾性係数が５０×１０^−１３cm^２／dyn以下である場合の好ましい光弾性係数は、４０×１０^−１３cm^２／dyn以下、就中３０×１０^−１３cm^２／dyn以下、特に２０×１０^−１３cm^２／dyn以下である。
【００１９】
また特定の波長域、特に短波長側で異なる位相差となって１／４波長板としての位相差特性を満足しなくなることを抑制する点などより、前記の△ｎ1／△ｎ2＜１．０５を満足する場合の好ましい△ｎ1／△ｎ2（以下同じ）は、０．９５〜１．０４、就中０．９７〜１．０３、特に０．９８〜１．０２である。一方、視角特性などの点より△ｎ1／△ｎ2＞１．０５を満足する場合の好ましい△ｎ1／△ｎ2は、１．０６〜５、就中１．１〜４、特に１．１５〜３である。なお上記した１／２波長の位相差を与える延伸フィルムの場合における高い光弾性係数としてはその位相差付与の加工性などの点より６０×１０^−１３cm^２／dyn以上、就中７０×１０^−１３cm^２／dyn以上、特に８０×１０^−１３cm^２／dyn以上であることが好ましい。
【００２０】
さらに前記した複屈折率差の波長依存性の満足性や特定の波長域での位相差の相違の抑制、視角変化による着色化の防止などの点よりは（ｎx−ｎz）／（ｎx−ｎy）＝Ｎz（以下同じ）として、式：０＜Ｎz≦１、就中０．３≦Ｎz≦０．７を満足する延伸フィルムを少なくとも１枚用いることが好ましい。なお前記式中のｎxは面内における最大屈折率、ｎyはｎxに直交する方向の屈折率、及びｎzは厚さ方向の屈折率である。従って前記の式は、ｎy≦ｎz＜ｎxを意味する。延伸フィルムの厚さ方向における屈折率を制御する必要のある場合には、例えば熱収縮性フィルムの接着下にポリマーフィルムを延伸処理する方式などにより行いうる。
【００２１】
位相差板の厚さは、目的とする位相差などに応じて適宜に決定しうるが、一般には柔軟性や薄型化などの点より１〜５００μm、就中５〜４００μm、特に１０〜３００μmとされる。位相差板は、上記した例より明らかな如く１層又は２層以上の適宜な枚数を用いることができる。
【００２２】
光散乱粘着層は、光透過性の無着色粒子を分散含有して光拡散性を示す光透過性の粘着層からなり、その光拡散性が、垂直入射光の垂直透過方向に対し１０度又は３０度傾斜した方向における透過光の強度を前者Ｉ_１０、後者Ｉ_３０としたとき１００×Ｉ_３０／Ｉ_１０で定義される光拡散率に基づいて１０％以下であるものからなる。
【００２３】
光散乱粘着層の形成には、光透過性を示す適宜な粘着性物質を用いることができ、その種類について特に限定はない。ちなみに前記粘着性物質の例としてはゴム系粘着剤やアクリル系粘着剤、シリコーン系粘着剤やビニルアルキルエーテル系粘着剤、ポリビニルアルコール系粘着剤やポリビニルピロリドン系粘着剤、ポリアクリルアミド系粘着剤やセルロース系粘着剤などがあげられる。粘着性物質は、光透過性に優れるものが好ましく耐候性等も加味した場合、特にアクリル系粘着剤が好ましく用いられる。なお光散乱粘着層は必要に応じて、接着力の調節などを目的に無着色粒子を含有しない普通の透明粘着層と重畳形態に形成されていてもよい。
【００２４】
光散乱粘着層に分散含有させる光透過性の無着色粒子としては、無色透明性の適宜なものを用いうる。ちなみにその例としては、シリカやアルミナ、チタニアやジルコニア、酸化錫や酸化インジウム、酸化カドミウムや酸化アンチモン等の導電性のこともある無機系粒子、架橋又は未架橋の各種ポリマー等からなる有機系粒子などがあげられる。無着色粒子は、１種又は２種以上を用いることができる。
【００２５】
光散乱粘着層の形成は、例えば粘着性物質と光透過性の無着色粒子の混合物をカレンダーロール法等による圧延方式、ドクターブレード法やグラビアロールコータ法等による塗工方式などの適宜な方式で偏光板や位相差板等からなる支持基材に付設する方式、あるいはその支持基材にセパレータを用いてそのセパレータ上に前記に準じ光散乱粘着層を形成してそれを偏光板や位相差板等からなる他の支持基材に移着する方式などの適宜な方式で行うことができる。
【００２６】
前記において本発明においては、無着色粒子の含有により光拡散率が１０％以下の光拡散性を示す光散乱粘着層として形成することが必要である。その光拡散率が１０％を超えると光の拡散度が過大となり、反射型液晶表示装置を照明下に視認する場合の正面（垂直）方向の明るさに乏しくなる。光の拡散性による良視認の視野角の拡大と前記正面方向の明るさとのバランスなどの点より好ましい光拡散率は、１〜９％、就中１．５〜８％、特に２〜７％である。
【００２７】
なお前記の光拡散率は、図３に例示した如く光散乱粘着層２に垂直光Ｈを入射させた場合に、その垂直入射光Ｈの垂直透過方向Ｉ_０に対し１０度傾斜した方向における透過光の強度をＩ_１０、前記Ｉ_０に対し３０度傾斜した方向における透過光の強度をＩ_３０としたとき、１００×Ｉ_３０／Ｉ_１０（％）にて定義される。
【００２８】
前記した光拡散率の達成性と接着力の制御性などの点より好ましく用いうる無着色粒子は、その平均粒径が０．５〜１０μm、就中１〜９μm、特に２〜８μmのものである。また後方散乱を抑制して透過方向に良好な拡散性をもたせる点などよりは無着色粒子の屈折率をｎ^１、粘着層の屈折率をｎ^２としたとき、式：０．０１＜┃ｎ^１−ｎ^２┃＜０．１、就中┃ｎ^１−ｎ^２┃＜０．０９、特に−０．０８＜ｎ^１−ｎ^２＜−０．０１を満足する組合せとしたものが好ましい。
【００２９】
なお光散乱粘着層に分散含有させる光透過性の無着色粒子の量は、上記した光拡散率などに基づいて適宜に決定されるが一般には、接着力を確保する点などより粘着層（固形分）１００重量部あたり、１〜２００重量部、就中５〜１５０重量部、特に８〜１００重量部の無着色粒子が用いられる。また光散乱粘着層の厚さは、目的とする光拡散率や接着力などに応じて決定しうるが一般には３００μm以下、就中１〜２００μm、特に５〜１００μmの厚さとされる。
【００３０】
本発明による散乱型楕円偏光板は、図１や図２の例の如く偏光板１と１層又は２層以上の位相差板３、３１、３２と光散乱粘着層２を具備する適宜な層形態を有するものとして形成することができる。その場合、光散乱粘着層２は、例えば図１（ａ）の如く偏光板１と位相差板３の間や図２（ａ）の如く位相差板３１、３２の間、あるいは図１（ｂ）や図２（ｂ）の如く位相差板３、３２側の外側などの適宜な位置に配置することができる。その場合、光散乱粘着層は適宜な位置に２層以上を配置することもできるが、一般には光の拡散性による良視認の視野角の拡大と正面方向の明るさとのバランスなどの点より図例の如く１層の配置が好ましい。
【００３１】
前記において散乱型楕円偏光板を形成する偏光板や位相差板は、単に重ね置いた分離状態にあってもよいが、層間の屈折率調節による反射の抑制や光学系のズレ防止、ゴミ等の異物の侵入防止などの点より図例の如くその一部、就中、全体が密着一体化状態に固着処理されていることが好ましい。その固着処理に用いる光散乱粘着層以外の透明接着層は、適宜な接着剤を用いて無着色粒子を含有しない非散乱性のものとして形成することができる。
【００３２】
前記の透明接着層としては構成部材の光学特性の変化防止などの点より接着処理時の硬化や乾燥の際に高温のプロセスを要しないものが好ましく、長時間の硬化処理や乾燥時間を要しないものが望ましい。かかる点よりは図例の如く普通の透明粘着層２１、２２が好ましく用いうる。なお光散乱粘着層又は普通の透明粘着層が表面に露出する場合には、散乱型楕円偏光板を実用に供するまでの間、その露出粘着面にセパレータなどを仮着して汚染等より保護することが好ましい。
【００３３】
散乱型楕円偏光板の形成に際しては、その片側又は両側の外表面に必要に応じて図１（ｂ）に例示した如く表面特性改善層を設けることもできる。その表面特性改善層としては、例えば表面反射の防止を目的とした反射防止層や防眩処理層、あるいは表面保護を目的としたハードコート層などがあげられる。反射防止層や防眩処理層やハードコート層は、その２層以上を重複して設けることもできる。上記した広域型１／４波長板は、優れた反射防止機能も具備するものであるがその広域型１／４波長板を用いた場合にも表面特性改善層を設けうる。
【００３４】
なお反射型液晶表示装置などでは通例、偏光板が外表面側となるように散乱型楕円偏光板が適用される。従ってその場合、前記の反射防止層等は、偏光板の外表面に設けられることとなるが、そのときには偏光板に反射防止層や防眩処理層やハードコート層の１層又は２層以上を予め設けてその偏光板を位相差板等との積層に供することもできる。
【００３５】
前記した反射防止層は、例えばフッ素系ポリマーのコート層や多層金属蒸着膜等の光干渉性の膜などとして適宜に形成することができる。また防眩処理層についても、上記した散乱層などに準じて表面反射光が拡散する適宜な方式にて形成することができる。さらにハードコート層についても、例えばシリコーン系樹脂の硬化膜などからなる適宜な硬質膜にて形成することができる。
【００３６】
本発明による散乱型楕円偏光板、特に位相差板に１／４波長板を用いたものは、偏光板から１／４波長板への透過光路で自然光を円偏光に変換することより円偏光形成板や反射防止フィルターなどとして有用であり、１／４波長板側から入射させる逆光路では円偏光を直線偏光化して偏光板に供給することより、コレステリック液晶等の円偏光分離層を用いたバックライトシステムの直線偏光形成板などとして有用である。従って本発明による散乱型楕円偏光板は、前記の機能等を利用した適宜な目的に用いうるが就中、一層の偏光板を介した偏光子・検光子兼用の偏光制御性に優れることより明るさの向上を目的に裏面への偏光板の配置を省略した反射型液晶表示装置の形成などに好ましく用いうる。
【００３７】
かかる反射型液晶表示装置に本発明による散乱型楕円偏光板を用いることにより、裏面への偏光板の配置の省略による明るさの向上を実現しつつ、白さや解像度等の視認特性に優れるものを得ることができる。特に広域型１／４波長板を用いた場合には、明るくてコントラストに優れ正面と斜視で色相違が生じにくくて視認特性や視角特性に優れると共に、耐熱性等の耐久性にも優れる反射型液晶表示装置を得ることができる。
【００３８】
図４に前記した反射型液晶表示装置の例を示した。５が散乱型楕円偏光板であり、その偏光板１が外表面側となるように配置されている。また６が液晶セルであり、液晶６２を封止材６５を介して封入するセル基板６１，６３の視認背面側（裏面側）の基板６３におけるセルの内部側に、光反射性金属などからなる反射層兼用の電極６４が付設されている。図例ではセル内部に反射層兼用の電極６４を設けたものを示したが、本発明においては上記した散乱型楕円偏光板を用いる点を除いて特に限定はなく、例えば偏光板をセルの表裏に配置するものの如く電極をＩＴＯなどからなる透明電極として、視認背面側のセル基板６３の外側に反射層を設けた形態のものなどのように、従来に準じたものとして形成することができる。
【００３９】
なお前記の反射型又はそれ以外の液晶表示装置の形成に際しては、例えば光拡散板、プリズムシートやレンズシートの如き光路制御板、導光板等のバックライトや偏光分離板などの従来に準じた適宜な光学部材を適宜に配置しうるが、前記した反射型のものとする場合には本発明による散乱型楕円偏光板及びそれを液晶セルに接着するための接着層以外の偏光板や位相差板は、装置の薄型化や散乱型楕円偏光板の機能阻害を防止する点などより配置しないことが好ましい。
【００４０】
前記において本発明による散乱型楕円偏光板は、液晶セル上への位相差板等の順次積層方式や予め積層一体化したものの液晶セル上への配置方式などの適宜な方式で形成することができる。作業効率や光学特性の精度などの点よりは、予め積層一体化した散乱型楕円偏光板を用いる方式が好ましい。散乱型楕円偏光板や液晶表示装置を形成する偏光板や位相差板、光散乱粘着層や接着層等の各部品は、例えばサリチル酸エステル系化合物やベンゾフェノン系化合物、ベンゾトリアゾール系化合物やシアノアクリレート系化合物、ニッケル錯塩系化合物等の紫外線吸収剤で処理されたものの如く紫外線吸収能をもたせたものであってもよい。
【００４１】
【実施例】
参考例１
屈折率１．５９、厚さ５０μmのポリカーボネートフィルムを１５０℃で２．５％延伸処理し、複屈折光に基づいて波長５５０nmの光に対して１／４波長の位相差を与えるＮzが１の延伸フィルムを得た。
【００４２】
参考例２
参考例１に準じ、５％の延伸処理条件として、複屈折光に基づいて波長５５０nmの光に対して１／２波長の位相差を与える光弾性係数が９０×１０^−１３cm^２／dyn、△ｎ1／△ｎ2が１．１６で、Ｎzが１の延伸フィルムを得た。
【００４３】
実施例１
屈折率（ｎ^１）が１．４３、平均粒径が４μmの光透過性無着色粒子をアクリル系粘着剤に混合してセパレータ上に塗工することにより、屈折率（ｎ^２）１．４７、厚さ２５μmの透明なアクリル系粘着層内に前記の無着色粒子を３３重量％の割合で分散含有する光散乱粘着層を得た。この光散乱粘着層を参考例１で得た延伸フィルムの片面に付設し、その粘着層を介し反射防止層付きの防眩偏光板（日東電工社製、ＮＰＦ−ＥＧ１４２５ＤＵＡＧ３０ＡＲＳ、以下同じ）と圧着積層して散乱型楕円偏光板を得た。なお偏光板の吸収軸と延伸フィルムの光軸（延伸軸）の交差角は、４５度とした。
【００４４】
実施例２
参考例１で得た延伸フィルムに代えて参考例２で得た延伸フィルムを用いると共に、その延伸フィルムの露出側に厚さ２５μmの非散乱型アクリル系粘着剤を介し参考例１で得た延伸フィルムを光軸を交差させて圧着積層して散乱型楕円偏光板を得た。なお偏光板の吸収軸に対する光軸の交差角は、参考例１の延伸フィルムが１２度、参考例２の延伸フィルムが６９度である。
【００４５】
実施例３
参考例２の延伸フィルムと偏光板の間の粘着層を非散乱型アクリル系粘着層とすると共に、参考例１の延伸フィルムの露出側に光散乱粘着層を設けたほかは実施例２に準じて散乱型楕円偏光板を得た。
【００４６】
比較例
光散乱粘着層として、屈折率（ｎ^１）が１．６３、平均粒径が６μmの光透過性無着色粒子を屈折率（ｎ^２）１．４７、厚さ２５μmの透明なアクリル系粘着層内に１８重量％の割合で分散含有するものを用いたほかは実施例１に準じて、散乱型楕円偏光板を得た。
【００４７】
評価試験
光拡散率
実施例１、比較例で得た光散乱粘着層の本発明にて定義される光拡散率を調べると共に、その光散乱粘着層を鏡面反射板上に接着して拡散光を入射させ、その正面（法線）方向の明るさを標準白色板の反射強度と比較した。なお光散乱粘着層は、鏡面反射板に強力に接着した。
【００４８】
偏光制御性（広帯域性）
実施例、比較例で得た散乱型楕円偏光板を鏡面反射板の上に置き、その反射板を介した透過反射光の正面での反射色を目視観察して、偏光子・検光子兼用の偏光の制御性を調べ、次の基準で評価した。
Ａ：反射色が黒い場合
Ｂ：反射色が青い場合
Ｃ：反射色が明るくて青い場合
【００４９】
視認（視角）特性
実施例、比較例で得た散乱型楕円偏光板において偏光板を除去した構造のものを鏡面反射板の上に置き、その反射板を介した透過反射光の正面と斜め４５度での反射色を目視観察し、次の基準で評価した。
Ａ：正面、斜視共に明るい場合
Ｂ：正面は明るいが斜視の明るさが不足する場合
Ｃ：正面、斜視共に明るさが不足する場合
【００５０】
解像性
実施例、比較例で得た散乱型楕円偏光板において偏光板を除去した構造のものを文字を印刷した鏡面反射板の上に置き、その反射板を介した透過反射光の正面と斜め４５度での反射色による文字を目視観察し、次の基準で評価した。
Ａ：正面、斜視共に文字に滲みがなく、良好に判読できる場合
Ｂ：正面は文字に滲みがないが斜視は文字の滲みで判読不良の場合
Ｃ：正面、斜視共に文字の滲みで判読不良の場合
【００５１】
前記の結果を次表に示した。

【図面の簡単な説明】
【図１】散乱型楕円偏光板例の断面図
【図２】他の散乱型楕円偏光板例の断面図
【図３】光拡散率の算出説明図
【図４】反射型液晶表示装置例の断面図
【符号の説明】
５：散乱型楕円偏光板
１：偏光板 ２：光散乱粘着層 ３、３１、３２：位相差板
４：表面特性改善層
６：液晶セル（６４：反射層を兼ねる電極）[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a scattering-type elliptically polarizing plate suitable for forming a liquid crystal display device having an excellent balance between light transmittance and diffusibility and excellent visibility such as brightness.
[0002]
BACKGROUND OF THE INVENTION
Conventionally, there has been known a reflection type liquid crystal display device in which an electrode 64 serving also as a light reflection layer is provided inside the liquid crystal cell 6 as illustrated in FIG. Since it is necessary to improve the display luminance with the colorization of the liquid crystal display, the object is achieved by reducing the light absorption loss by omitting the polarizing plate. In that case, for the polarizing plate on the viewing side, there is a method of adhering with a light diffusive pressure-sensitive adhesive layer containing light diffusibility by containing particles having different refractive indexes for the purpose of improving the viewing angle and brightness. It was taken. However, if the diffusibility is enhanced while satisfying the adhesive processability with excellent reliability, there is a problem that the transmittance decreases due to an increase in backscattering, the brightness and visibility are lowered, and it is difficult to balance them.
[0003]
[Technical Problem of the Invention]
An object of the present invention is to develop a scattering-type elliptically polarizing plate that can form a reflective liquid crystal display device that is excellent in brightness and visibility while satisfying adhesive processing properties that are excellent in reliability.
[0004]
[Means for solving problems]
  The present invention comprises a polarizing plate, a retardation plate having one or more layers, and light-transmitting uncolored particles.Adhesive layerA light-scattering adhesive layer comprising a laminate having a light-transmitting light-scattering adhesive layer that is dispersed and exhibits light diffusivityThe content of the uncolored particles is 8 to 100 parts by weight per 100 parts by weight of the adhesive layer (solid content) (except that the content of the uncolored particles is 5 to 30 parts by weight), The refractive index of the uncolored particles is n ¹ , The refractive index of the adhesive layer is n ² -0.08 <n ¹ -N ² <−0.01 is satisfied,The light diffusibility indicates the intensity of transmitted light in a direction inclined by 10 degrees or 30 degrees with respect to the perpendicular transmission direction of perpendicular incident light.₁₀The latter I₃₀100 × I₃₀/ I₁₀A scattering type elliptically polarizing plate characterized in that it is 10% or less based on the light diffusivity defined in the above, and a reflective type liquid crystal display comprising the scattering type elliptically polarizing plate on the viewing side of the liquid crystal cell A device is provided.
[0005]
【The invention's effect】
According to the present invention, it is possible to obtain a scattering-type elliptically polarizing plate that can be reliably bonded with the light-scattering adhesive layer and has an excellent balance between light transmittance and diffusivity based on the light diffusivity. Can be used to obtain a liquid crystal display device excellent in brightness and visibility, particularly a reflective liquid crystal display device excellent in brightness in the front direction. Further, since the adhesive layer also serves as the light diffusing layer, it is possible to avoid the necessity of disposing a separate light diffusing plate, and it is possible to reduce the thickness and weight by omitting the liquid crystal display member.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The scattering-type elliptically polarizing plate according to the present invention comprises a light-transmitting light-scattering pressure-sensitive adhesive layer exhibiting light-diffusing properties by dispersing and containing light-transmitting non-colored particles and a polarizing plate, one or more retardation plates. The intensity of transmitted light in the direction in which the light-scattering adhesive layer is tilted by 10 degrees or 30 degrees with respect to the perpendicular transmission direction of the normal incident light is₁₀The latter I₃₀100 × I₃₀/ I₁₀Based on the light diffusivity defined in (1), the light diffusivity is 10% or less. Examples thereof are shown in FIGS. Reference numeral 1 is a polarizing plate, 2 is a light scattering adhesive layer, 3, 31, 32 are retardation plates, 5 is a scattering elliptical polarizing plate, 21 and 22 are ordinary adhesive layers, and 4 is a surface property improving layer.
[0007]
A suitable polarizing plate can be used, and there is no particular limitation. In general, for example, a film of a hydrophilic polymer such as polyvinyl alcohol, partially formalized polyvinyl alcohol, or partially saponified ethylene / vinyl acetate copolymer is adsorbed with iodine and / or dichroic dye, and stretched. A polarizing film made of a polyene-oriented film such as a dehydrated polyvinyl alcohol product or a dehydrochlorinated polyvinyl chloride product is used. The thickness of the polarizing film is usually 5 to 80 μm, but is not limited thereto.
[0008]
The polarizing plate may be one in which one side or both sides of a polarizing film is covered with a transparent protective layer or the like. Such a transparent protective layer or the like may have various purposes such as reinforcing the polarizing film, improving heat resistance, and protecting the polarizing film from humidity or the like. The transparent protective layer can be formed as an appropriate resin coating layer, a resin film laminate layer, or the like. Therefore, any polarizing plate used for forming a conventional liquid crystal display device can be used.
[0009]
On the other hand, as a retardation plate, for example, a phase difference characteristic such as a half wavelength or a quarter wavelength with respect to monochromatic light, or a compensation for a phase difference due to the birefringence of a liquid crystal cell is used. Any suitable material exhibiting phase difference characteristics can be used. Accordingly, the retardation plate is made of, for example, polycarbonate, polyester, polysulfone, polyethersulfone, polystyrene, polyolefin, polyvinyl alcohol, cellulose acetate, polyacrylic, such as polyvinyl chloride or polymethyl methacrylate, A film made of an appropriate polymer such as an arylate, polyamide, polyimide, or polyvinylidene chloride is stretched by an appropriate method such as uniaxial or biaxial, or an appropriate liquid crystal film, etc. Good.
[0010]
A quarter-wave plate is preferably used from the viewpoint of compensating for the phase difference caused by the liquid crystal cell. The quarter-wave plate may give a quarter-wave phase difference to monochromatic light. However, high-contrast black-and-white display and high-color purity color by advanced compensation of the phase difference by the liquid crystal cell. Rather than achieving the display, it is preferable to function as a quarter-wave plate in a wide wavelength range such as the visible light range and exhibit a compensation effect in a wide wavelength range. That is, in general, a single-layer retardation plate made of a stretched film or the like has a wavelength difference that varies depending on the wavelength and exhibits wavelength dispersion, and a wavelength range that can function as a quarter-wave plate is narrow. In some cases, it is not possible to sufficiently compensate over the range. In such a case, a material that functions as a quarter-wave plate in a wide wavelength range is preferably used.
[0011]
The one that functions as a quarter-wave plate in the wide wavelength range, that is, the wide-band quarter-wave plate is, for example, a stretched film that gives a half-wave phase difference to monochromatic light and a quarter-wave plate. A plurality of stretched films giving a phase difference can be obtained as a laminated body in which the optical axes are crossed. According to this, the wavelength dispersion of the phase difference defined by the product (Δnd) of the birefringence difference (Δn) and the thickness (d) can be superposed or adjusted through the laminated stretched film and arbitrarily controlled. In addition, it is possible to obtain a wave plate that exhibits a ¼ wavelength phase difference over a wide wavelength range such as the entire visible light range while suppressing the chromatic dispersion while controlling the phase difference as a whole to a predetermined value.
[0012]
The number of laminated stretched films is arbitrary in the wide-area quarter-wave plate. From the viewpoint of light transmittance and the like, the lamination of 2 to 5 sheets is common. Moreover, the arrangement position of the stretched film which gives the phase difference of 1/2 wavelength and the stretched film which gives the phase difference of 1/4 wavelength are also arbitrary. By the way, taking the case of using one stretched film that gives a phase difference of 1/4 wavelength and arranging it at the light exit side end of the wide-band type 1/4 wavelength plate, the crossing angle of the optical axes of each stretched film and each The relationship of the polarization direction (θ) transmitted through the stretched film is expressed by the following equation.
[0013]
That is, the number of stretched films that give a half-wave phase difference is n, and they are represented by λ / 2 (1, 2,... N), and the polarization direction of the incident linearly polarized light is the reference (0 °) The stacking angle of each λ / 2 (1, 2,... N) is θ₁, Θ₂... θ_nThen, stacking angle = 2 (θ₁+ Θ₂+ ... + θ_n-1) + Θ_n
Direction of polarized light transmitted through each λ / 2 plate = 2 (θ₁+ Θ₂+ ... + θ_n)
A circularly polarized light can be obtained by laminating a stretched film, which is expressed by the following formula and gives a retardation of a quarter wavelength, at an angle of 45 degrees.
[0014]
The above-mentioned relationship is shown in the following table by taking as an example the case where three stretched films (λ / 2 (1, 2, 3)) giving a half-wave retardation are used. In addition, (lambda) / 4 represents the stretched film which gives the phase difference of 1/4 wavelength.

[0015]
In the above, at the time of forming a wide-band quarter-wave plate, photoelasticity with respect to light having a wavelength of 633 nm is obtained on at least one stretched film from the viewpoint that it has excellent heat resistance and is not easily different in phase difference characteristics between the front and the perspective. The coefficient is 50 × 10^-13cm²/ Dyn or less, and those whose birefringence difference Δn1, Δn2 has a wavelength dependency of Δn1 / Δn2 <1.05 based on wavelength light of 400 nm (Δn1) and 550 nm (Δn2) Is preferred. As a result, the black uniform reflected color in the front direction, which is generated based on the difference in phase difference characteristics between the front (vertical) and the oblique direction in the transmitted reflected light through the reflective layer on the back surface, is somewhat The phenomenon of changing to bright blue or light yellow can be prevented or suppressed.
[0016]
From the viewpoint of easy feasibility of wavelength dependency of the photoelastic coefficient and birefringence difference, the polymer for forming the stretched film is polyolefin, especially cyclic olefin, cellulose acetate, polymethyl methacrylate. A system or the like can be preferably used. Further, such a polymer can be particularly preferably used for forming a stretched film giving a quarter-wave retardation. Further, the stretched film satisfying the wavelength dependency of the photoelastic coefficient and birefringence difference described above can be preferably used as a single-layer quarter-wave plate from the viewpoint of suppressing color change between the front and the perspective.
[0017]
On the other hand, for the formation of a stretched film that gives a phase difference of ½ wavelength, the workability for imparting the phase difference, the application of a high photoelastic coefficient, and the wavelength light of 400 nm (Δn1) and 550 nm (Δn2) are used. On the basis of the difference in birefringence difference Δn 1 and Δn 2 satisfying the wavelength dependency of Δn 1 / Δn 2> 1.05, suppressing the difference in phase difference between the front and the perspective, and thus improving the viewing angle characteristic, etc. In view of the above, for example, a polymer such as polycarbonate, polysulfone, polyethersulfone, or polyarylate can be particularly preferably used.
[0018]
Therefore, the photoelastic coefficient for light having a wavelength of 633 nm is 50 × 10, rather than obtaining a wide-range quarter-wave plate excellent in heat resistance and viewing angle characteristics as described above.^-13cm²For a monochromatic light satisfying Δn1 / Δn2 <1.05 at less than / dyn and for a monochromatic light satisfying Δn1 / Δn2> 1.05 It is preferable to use a combination with a stretched film that gives a retardation of ½ wavelength. A stretched film that satisfies the photoelastic coefficient and Δn1 / Δn2 can be obtained by controlling the type of forming material, stretching conditions, and the like. The photoelastic coefficient for light having a wavelength of 633 nm is 50 × 10 5 from the viewpoint of improving heat resistance.^-13cm²A preferable photoelastic coefficient in the case of / dyn or less is 40 × 10^-13cm²/ Dyn or less, especially 30 × 10^-13cm²/ Dyn or less, especially 20 × 10^-13cm²/ Dyn or less.
[0019]
In addition, the above-mentioned Δn1 / Δn2 <1.05 is achieved because it is possible to suppress a phase difference that is different in a specific wavelength region, particularly on a short wavelength side, and the phase difference characteristic as a quarter-wave plate is not satisfied. Δn1 / Δn2 (hereinafter the same) is preferably 0.95 to 1.04, more preferably 0.97 to 1.03, and particularly 0.98 to 1.02. On the other hand, the preferable Δn1 / Δn2 in the case of satisfying Δn1 / Δn2> 1.05 from the viewpoint of viewing angle characteristics, etc. is 1.06-5, especially 1.1-4, especially 1.15-3. It is. In addition, as a high photoelastic coefficient in the case of the stretched film which gives the phase difference of 1/2 wavelength mentioned above, 60 * 10 from the point of the workability of the phase difference provision, etc.^-13cm²/ Dyn or more, especially 70 × 10^-13cm²/ Dyn or more, especially 80 × 10^-13cm²/ Dyn or more is preferable.
[0020]
Further, in terms of satisfaction of the wavelength dependency of the above-described birefringence difference, suppression of a difference in phase difference in a specific wavelength range, prevention of coloring due to a change in viewing angle, and the like, (nx−nz) / (nx−ny). ) = Nz (hereinafter the same), it is preferable to use at least one stretched film satisfying the formula: 0 <Nz ≦ 1, especially 0.3 ≦ Nz ≦ 0.7. In the above formula, nx is the maximum in-plane refractive index, ny is the refractive index in the direction perpendicular to nx, and nz is the refractive index in the thickness direction. Therefore, the above equation means ny ≦ nz <nx. When it is necessary to control the refractive index in the thickness direction of the stretched film, it can be performed, for example, by a method of stretching a polymer film under the adhesion of a heat-shrinkable film.
[0021]
The thickness of the phase difference plate can be appropriately determined according to the target phase difference and the like, but generally from 1 to 500 μm, especially from 5 to 400 μm, especially from 10 to 300 μm from the viewpoint of flexibility and thinning. Is done. As is clear from the above example, the retardation plate can be used in an appropriate number of one layer or two or more layers.
[0022]
The light scattering pressure-sensitive adhesive layer is composed of a light-transmitting pressure-sensitive adhesive layer that contains light-transmitting non-colored particles in a dispersed manner and exhibits light diffusivity. The intensity of transmitted light in the direction inclined by 30 degrees is expressed by the former I.₁₀The latter I₃₀100 × I₃₀/ I₁₀And 10% or less based on the light diffusivity defined by.
[0023]
For the formation of the light-scattering adhesive layer, an appropriate adhesive substance exhibiting light transmittance can be used, and the type thereof is not particularly limited. By the way, examples of the above-mentioned adhesive substances include rubber adhesives, acrylic adhesives, silicone adhesives, vinyl alkyl ether adhesives, polyvinyl alcohol adhesives, polyvinyl pyrrolidone adhesives, polyacrylamide adhesives and cellulose. System adhesives and the like. The adhesive substance is preferably excellent in light transmittance, and an acrylic adhesive is particularly preferably used in consideration of weather resistance and the like. In addition, the light-scattering adhesive layer may be formed in a superimposed form with an ordinary transparent adhesive layer that does not contain uncolored particles for the purpose of adjusting the adhesive force, if necessary.
[0024]
As the light-transmitting non-colored particles dispersed and contained in the light-scattering adhesive layer, appropriate colorless and transparent particles can be used. Examples include inorganic particles that may be conductive such as silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, and antimony oxide, and organic particles composed of various crosslinked or uncrosslinked polymers. Etc. One type or two or more types of non-colored particles can be used.
[0025]
The light-scattering adhesive layer is formed by an appropriate method such as a rolling method using a calender roll method or a coating method using a doctor blade method or a gravure roll coater method, for example, a mixture of an adhesive substance and light-transmitting uncolored particles. A method of attaching to a support substrate composed of a polarizing plate, a retardation plate, or the like, or using a separator on the supporting substrate, forming a light scattering adhesive layer on the separator according to the above, and applying the light scattering adhesive layer to the polarizing plate or retardation plate It can carry out by suitable methods, such as the method of transferring to the other support base material which consists of etc.
[0026]
In the present invention, in the present invention, it is necessary to form a light-scattering adhesive layer exhibiting light diffusivity with a light diffusivity of 10% or less due to the inclusion of non-colored particles. When the light diffusivity exceeds 10%, the degree of light diffusion becomes excessive, and the brightness in the front (vertical) direction when the reflective liquid crystal display device is viewed under illumination is poor. The light diffusivity is more preferably 1 to 9%, especially 1.5 to 8%, especially 2 to 7% in terms of the balance between the wide viewing angle due to light diffusibility and the brightness in the front direction. It is.
[0027]
The light diffusivity is the vertical transmission direction I of the vertical incident light H when the vertical light H is incident on the light scattering adhesive layer 2 as illustrated in FIG.₀The intensity of transmitted light in a direction inclined 10 degrees with respect to I₁₀, I₀The intensity of transmitted light in the direction inclined by 30 degrees with respect to I₃₀100 × I₃₀/ I₁₀(%)
[0028]
The non-colored particles that can be preferably used in view of the achievement of the light diffusivity and the controllability of the adhesive force are those having an average particle size of 0.5 to 10 μm, especially 1 to 9 μm, especially 2 to 8 μm. is there. In addition, the refractive index of the non-colored particles is set to n from the point of suppressing the backscattering and providing good diffusibility in the transmission direction.¹, The refractive index of the adhesive layer is n²The formula: 0.01 <┃n¹-N²┃ <0.1, n¹-N²┃ <0.09, especially -0.08 <n¹-N²A combination satisfying <−0.01 is preferable.
[0029]
The amount of light-transmitting non-colored particles to be dispersed and contained in the light-scattering adhesive layer is appropriately determined based on the above-described light diffusivity and the like. Min) 1 to 200 parts by weight, in particular 5 to 150 parts by weight, in particular 8 to 100 parts by weight of uncolored particles are used per 100 parts by weight. The thickness of the light-scattering pressure-sensitive adhesive layer can be determined according to the desired light diffusivity and adhesive force, but is generally 300 μm or less, in particular 1 to 200 μm, and particularly 5 to 100 μm.
[0030]
The scattering-type elliptically polarizing plate according to the present invention is a suitable layer comprising a polarizing plate 1, one or more retardation plates 3, 31, 32 and a light scattering adhesive layer 2 as in the examples of FIGS. 1 and 2. It can be formed as having a form. In that case, the light scattering adhesive layer 2 is formed between the polarizing plate 1 and the retardation plate 3 as shown in FIG. 1A, between the retardation plates 31 and 32 as shown in FIG. ) And FIG. 2 (b), it can be arranged at an appropriate position such as the outer side of the phase difference plates 3 and 32. In that case, two or more light scattering adhesive layers can be arranged at an appropriate position, but in general, the light scattering adhesive layer is shown in terms of the balance between the wide viewing angle due to light diffusibility and the brightness in the front direction. A single layer arrangement is preferred as in the example.
[0031]
In the above, the polarizing plate and the retardation plate that form the scattering-type elliptical polarizing plate may be simply separated from each other. However, the reflection is suppressed by adjusting the refractive index between layers, the optical system is prevented from being displaced, dust, etc. From the standpoint of preventing the entry of foreign matter, it is preferable that a part, especially the whole, is fixedly adhered in a tightly integrated state as shown in the figure. The transparent adhesive layer other than the light scattering pressure-sensitive adhesive layer used for the fixing treatment can be formed as a non-scattering material containing no uncolored particles using an appropriate adhesive.
[0032]
The transparent adhesive layer is preferably one that does not require a high-temperature process for curing or drying during the adhesion process, from the viewpoint of preventing changes in the optical properties of the constituent members, and does not require a long curing process or drying time. Things are desirable. From this point, ordinary transparent adhesive layers 21 and 22 can be preferably used as shown in the figure. If the light scattering adhesive layer or the ordinary transparent adhesive layer is exposed on the surface, a separator is temporarily attached to the exposed adhesive surface until it is practically used to protect it from contamination. It is preferable.
[0033]
When forming the scattering-type elliptically polarizing plate, a surface property improving layer can be provided on the outer surface of one side or both sides as shown in FIG. Examples of the surface property improving layer include an antireflection layer and an antiglare layer for the purpose of preventing surface reflection, and a hard coat layer for the purpose of surface protection. Two or more antireflection layers, antiglare treatment layers and hard coat layers can be provided in duplicate. The above-described wide-area type quarter-wave plate also has an excellent antireflection function, but even when the wide-area type quarter-wave plate is used, a surface property improving layer can be provided.
[0034]
In a reflective liquid crystal display device or the like, a scattering type elliptically polarizing plate is usually applied so that the polarizing plate is on the outer surface side. Therefore, in this case, the antireflection layer or the like is provided on the outer surface of the polarizing plate. At that time, the polarizing plate is provided with one or more layers of the antireflection layer, the antiglare treatment layer, and the hard coat layer. The polarizing plate may be provided in advance and used for lamination with a retardation plate or the like.
[0035]
The antireflection layer described above can be suitably formed as a light interference film such as a coating layer of a fluorine-based polymer or a multilayer metal vapor deposition film. The antiglare layer can also be formed by an appropriate method in which the surface reflected light diffuses in accordance with the scattering layer described above. Further, the hard coat layer can be formed of an appropriate hard film made of, for example, a cured film of a silicone resin.
[0036]
The scattering-type elliptically polarizing plate according to the present invention, particularly one using a quarter wave plate as a retardation plate, forms circularly polarized light by converting natural light into circularly polarized light in the transmission light path from the polarizing plate to the quarter wave plate. It is useful as a plate or antireflection filter. In the reverse optical path that is incident from the quarter-wave plate side, circularly polarized light is linearly polarized and supplied to the polarizing plate, so that a back surface using a circularly polarized light separating layer such as cholesteric liquid crystal is used. It is useful as a linear polarization plate for a light system. Therefore, although the scattering-type elliptically polarizing plate according to the present invention can be used for an appropriate purpose utilizing the above-mentioned functions, it is brighter than being excellent in polarization controllability for both a polarizer and an analyzer through a single polarizing plate. For the purpose of improving the thickness, it can be preferably used for the formation of a reflective liquid crystal display device in which the arrangement of the polarizing plate on the back surface is omitted.
[0037]
By using the scattering-type elliptically polarizing plate according to the present invention for such a reflective liquid crystal display device, it is possible to improve the brightness by omitting the arrangement of the polarizing plate on the back surface and to have excellent visual characteristics such as whiteness and resolution. Obtainable. In particular, when a wide-range quarter-wave plate is used, it is bright and has excellent contrast, and it is less likely to cause a color difference between the front and perspective, and has excellent visual characteristics and viewing angle characteristics, as well as durability such as heat resistance. A liquid crystal display device can be obtained.
[0038]
FIG. 4 shows an example of the reflection type liquid crystal display device described above. Reference numeral 5 denotes a scattering-type elliptically polarizing plate, and the polarizing plate 1 is disposed on the outer surface side. Reference numeral 6 denotes a liquid crystal cell, which is made of a light-reflecting metal or the like on the inner side of the cell in the substrate 63 on the rear side (back side) of the cell substrates 61 and 63 in which the liquid crystal 62 is sealed through the sealing material 65. An electrode 64 also serving as a reflective layer is attached. In the example shown in the figure, the electrode 64 also serving as a reflective layer is provided inside the cell. However, in the present invention, there is no particular limitation except that the above-described scattering type elliptical polarizing plate is used. The electrode can be formed as a transparent electrode made of ITO or the like, as in the case of the above, and can be formed in accordance with the conventional case, such as a configuration in which a reflective layer is provided on the outside of the cell substrate 63 on the viewing back side.
[0039]
When forming the reflection type or other liquid crystal display devices, for example, a light diffusing plate, an optical path control plate such as a prism sheet or a lens sheet, a backlight such as a light guide plate, or a polarization separation plate, as appropriate according to the prior art. However, in the case of the reflection type, the scattering type elliptical polarizing plate according to the present invention and a polarizing plate and a retardation plate other than the adhesive layer for adhering it to the liquid crystal cell It is preferable not to arrange them because the thickness of the apparatus is reduced or the function of the scattering-type elliptically polarizing plate is prevented.
[0040]
In the above, the scattering-type elliptically polarizing plate according to the present invention can be formed by an appropriate method such as a sequential lamination method such as a retardation plate on a liquid crystal cell, or an arrangement method in which a previously laminated and integrated material is placed on a liquid crystal cell. . From the viewpoint of work efficiency and accuracy of optical characteristics, a method using a scattering-type elliptically polarizing plate laminated and integrated in advance is preferable. Each component such as a scattering-type elliptically polarizing plate, a polarizing plate, a retardation plate, a light scattering adhesive layer and an adhesive layer forming a liquid crystal display device includes, for example, salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, and cyanoacrylate compounds. It may have a UV-absorbing ability such as a compound or a nickel complex salt-based compound treated with an UV absorber.
[0041]
【Example】
Reference example 1
A polycarbonate film having a refractive index of 1.59 and a thickness of 50 μm is stretched by 2.5% at 150 ° C., and Nz is 1 which gives a phase difference of ¼ wavelength to light having a wavelength of 550 nm based on birefringent light. A stretched film was obtained.
[0042]
Reference example 2
According to Reference Example 1, as a stretching treatment condition of 5%, a photoelastic coefficient that gives a phase difference of ½ wavelength with respect to light having a wavelength of 550 nm based on birefringent light is 90 × 10^-13cm²A stretched film having / dyn, Δn1 / Δn2 of 1.16 and Nz of 1 was obtained.
[0043]
Example 1
Refractive index (n¹) Is 1.43 and the average particle diameter is 4 μm, and light-transmitting non-colored particles are mixed with an acrylic pressure-sensitive adhesive and coated on a separator to obtain a refractive index (n²1) A light-scattering pressure-sensitive adhesive layer in which the uncolored particles were dispersed and contained at a ratio of 33% by weight in a transparent acrylic pressure-sensitive adhesive layer having a thickness of 1.47 and 25 μm was obtained. This light-scattering adhesive layer is attached to one side of the stretched film obtained in Reference Example 1, and an antiglare polarizing plate with an antireflection layer (manufactured by Nitto Denko Corporation, NPF-EG1425DUAG30ARS, the same applies hereinafter) is laminated by pressure through the adhesive layer. Thus, a scattering-type elliptically polarizing plate was obtained. The crossing angle between the absorption axis of the polarizing plate and the optical axis (stretching axis) of the stretched film was 45 degrees.
[0044]
Example 2
The stretched film obtained in Reference Example 1 was used in place of the stretched film obtained in Reference Example 1, and the stretched film obtained in Reference Example 1 was passed through a non-scattering acrylic adhesive having a thickness of 25 μm on the exposed side of the stretched film. The film was pressed and laminated with the optical axes crossed to obtain a scattering-type elliptically polarizing plate. The crossing angle of the optical axis with respect to the absorption axis of the polarizing plate is 12 degrees for the stretched film of Reference Example 1 and 69 degrees for the stretched film of Reference Example 2.
[0045]
Example 3
Scattering according to Example 2 except that the adhesive layer between the stretched film of Reference Example 2 and the polarizing plate is a non-scattering acrylic adhesive layer and a light scattering adhesive layer is provided on the exposed side of the stretched film of Reference Example 1. A mold elliptically polarizing plate was obtained.
[0046]
Comparative example
Refractive index (n¹) Is 1.63 and the average particle size is 6 μm.²) A scattering-type elliptically polarizing plate was obtained in the same manner as in Example 1 except that a transparent acrylic adhesive layer having a thickness of 1.47 and a thickness of 25 μm was dispersed and contained at a ratio of 18% by weight.
[0047]
Evaluation test
Light diffusivity
Example 1 In addition to examining the light diffusivity defined in the present invention of the light scattering adhesive layer obtained in Example 1 and Comparative Example, the light scattering adhesive layer was adhered onto the specular reflector, and diffused light was incident thereon. The brightness in the (normal) direction was compared with the reflection intensity of a standard white plate. The light scattering adhesive layer was strongly bonded to the specular reflector.
[0048]
Polarization controllability (broadband)
The scattering-type elliptically polarizing plate obtained in Examples and Comparative Examples is placed on a specular reflection plate, and the reflected color in front of the transmitted / reflected light passing through the reflection plate is visually observed to be used as a polarizer / analyzer. The controllability of polarized light was examined and evaluated according to the following criteria.
A: When the reflection color is black
B: When the reflection color is blue
C: When the reflected color is bright and blue
[0049]
Visual (visual angle) characteristics
In the scattering elliptical polarizing plate obtained in Examples and Comparative Examples, the structure in which the polarizing plate is removed is placed on a specular reflection plate, and the reflected color at an angle of 45 degrees with the front of the transmitted reflected light through the reflection plate. Were visually observed and evaluated according to the following criteria.
A: When both front and perspective are bright
B: When the front is bright but the perspective is not bright enough
C: When brightness is insufficient for both front and perspective
[0050]
Resolution
In the scattering-type elliptical polarizing plate obtained in Examples and Comparative Examples, the structure with the polarizing plate removed is placed on a specular reflecting plate on which characters are printed, and 45 degrees oblique to the front of the transmitted reflected light through the reflecting plate. The characters with the reflected color in were visually observed and evaluated according to the following criteria.
A: When there is no bleeding in the front and perspective, and it can be read well
B: When there is no bleeding on the front, but the perspective is blurred due to bleeding
C: In the case of poor reading due to bleeding of characters on the front and perspective
[0051]
The results are shown in the following table.

[Brief description of the drawings]
FIG. 1 is a sectional view of an example of a scattering-type elliptically polarizing plate.
FIG. 2 is a cross-sectional view of another example of a scattering-type elliptically polarizing plate.
FIG. 3 is an explanatory diagram of calculation of light diffusivity.
FIG. 4 is a sectional view of an example of a reflective liquid crystal display device.
[Explanation of symbols]
5: Scattering elliptical polarizing plate
1: Polarizing plate 2: Light scattering adhesive layer 3, 31, 32: Retardation plate
4: Surface property improvement layer
6: Liquid crystal cell (64: Electrode also serving as a reflective layer)

Claims (3)

A laminate comprising a polarizing plate, a retardation plate of one layer or two or more layers, and a light-transmitting light-scattering adhesive layer exhibiting light diffusibility by dispersing light-transmitting uncolored particles in the adhesive layer , In the light scattering adhesive layer , the content of the uncolored particles is 8 to 100 parts by weight per 100 parts by weight of the adhesive layer (solid content) (however, the content of the uncolored particles is 5 to 30 parts by weight). Except for the above), when the refractive index of the non-colored particles is n ¹ and the refractive index of the adhesive layer is n ² , −0.08 <n ¹ −n ² <−0.01 is satisfied, and light diffusibility is satisfied . However, when the intensity of the transmitted light in the direction inclined by 10 degrees or 30 degrees with respect to the vertical transmission direction of the normal incident light is defined as the former I ₁₀ and the latter I ₃₀ , the light diffusivity defined by 100 × I ₃₀ / I ₁₀ is obtained. A scattering-type elliptically polarizing plate characterized by being 10% or less based on the above.   The scattering-type elliptically polarizing plate according to claim 1, wherein the light scattering adhesive layer is located between the polarizing plate and the retardation plate, between two or more retardation plates, or outside the retardation plate side.   A reflective liquid crystal display device comprising the scattering-type elliptically polarizing plate according to claim 1 on the viewing side of a liquid crystal cell.

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