JP2002207118A - Polarizing film and liquid crystal display device - Google Patents
Polarizing film and liquid crystal display deviceInfo
- Publication number
- JP2002207118A JP2002207118A JP2001000331A JP2001000331A JP2002207118A JP 2002207118 A JP2002207118 A JP 2002207118A JP 2001000331 A JP2001000331 A JP 2001000331A JP 2001000331 A JP2001000331 A JP 2001000331A JP 2002207118 A JP2002207118 A JP 2002207118A
- Authority
- JP
- Japan
- Prior art keywords
- liquid crystal
- polarizing film
- film
- absorption
- light
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Links
Abstract
Description
【０００１】[0001]
【発明の技術分野】本発明は、液晶表示装置等の視認性
や耐久性の向上に有用な耐熱性に優れる偏光フィルムに
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing film having excellent heat resistance useful for improving visibility and durability of a liquid crystal display device and the like.
【０００２】[0002]
【発明の背景】従来、ヨウ素に代えて二色性染料を基材
中に吸着配向させてなる偏光板が知られていた（特開昭
６２−１２３４０５号公報等）。斯かる偏光板は耐熱性
を向上させたものである。すなわち液晶表示装置の普及
に伴い携帯電話やＰＤＡ等の屋外使用を伴うものや、車
載用ナビゲーションや液晶プロジェクタ用のものではそ
の過酷な使用条件に耐える耐熱性が要求され、ヨウ素使
用の偏光板ではヨウ素の昇華や錯体状態の変化等で偏光
機能が大きく低下し、斯かる高温下での使用に耐えない
ためである。BACKGROUND OF THE INVENTION Heretofore, there has been known a polarizing plate obtained by adsorbing and orienting a dichroic dye in a substrate in place of iodine (Japanese Patent Application Laid-Open No. 62-123405). Such a polarizing plate has improved heat resistance. In other words, with the spread of liquid crystal display devices, those involving outdoor use such as mobile phones and PDAs, and those for vehicle-mounted navigation and liquid crystal projectors are required to have heat resistance to withstand the harsh use conditions. For polarizing plates using iodine, This is because the polarization function is greatly reduced due to sublimation of iodine, a change in the state of the complex, and the like, and the use at such a high temperature cannot be tolerated.
【０００３】しかしながら従来の二色性染料を使用した
偏光板には、その色素の吸収二色比が低いためヨウ素使
用の偏光板に比べて光透過率と偏光度の両立性に劣る難
点があった。すなわち光透過率を優先して二色性色素の
濃度を薄くするとコントラストに乏しくなり、濃度を高
めるとコントラストは向上するものの光透過率が低下し
て暗くなるため光透過率と偏光度を両立させることが難
しく、ヨウ素使用の偏光板のように光透過率と偏光度に
優れてそれらが両立したものを得ることが困難な問題点
があった。However, a polarizing plate using a conventional dichroic dye has a drawback in that the compatibility between the light transmittance and the degree of polarization is inferior to a polarizing plate using iodine due to the low absorption dichroic ratio of the dye. Was. That is, if the density of the dichroic dye is reduced with priority given to the light transmittance, the contrast becomes poor. If the density is increased, the contrast is improved, but the light transmittance is lowered and the image becomes dark, so that both the light transmittance and the degree of polarization are compatible. However, there is a problem that it is difficult to obtain a polarizer excellent in light transmittance and polarization degree, which is compatible with both, like a polarizing plate using iodine.
【０００４】[0004]
【発明の技術的課題】本発明は、光透過率と偏光度に優
れると共に、耐熱性にも優れる偏光板の開発を課題とす
る。SUMMARY OF THE INVENTION An object of the present invention is to develop a polarizing plate which is excellent in light transmittance and degree of polarization and excellent in heat resistance.
【０００５】[0005]
【課題の解決手段】本発明は、ポリマーからなる透光性
フィルム中にそのポリマーとは異種の材料からなる微小
領域を分散含有してなり、その微小領域が５０℃以上の
加熱時に液晶化する複屈折性材料とその液晶化温度で二
色性を喪失しない吸収型二色性材料との混合層からなる
ことを特徴とする偏光フィルム、及び液晶セルの片側又
は両側に前記の偏光フィルムを有することを特徴とする
液晶表示装置を提供するものである。According to the present invention, a light-transmitting film made of a polymer contains finely divided regions made of a material different from the polymer dispersed therein, and the finely divided regions become liquid crystal when heated at 50 ° C. or more. A polarizing film comprising a mixed layer of a birefringent material and an absorption type dichroic material that does not lose dichroism at its liquid crystallizing temperature, and the polarizing film on one or both sides of a liquid crystal cell. It is intended to provide a liquid crystal display device characterized by the above.
【０００６】[0006]
【発明の効果】本発明によれば、微小領域中の吸収型二
色性材料が示す吸収軸方向の振動面を有する光成分の吸
収と、透過軸方向の振動面を有する光成分の透過を介し
て直線偏光が得られるが、その際に微小領域中の複屈折
性材料が直線偏光を強く散乱する光軸（△ｎ１方向）と
直線偏光を効率よく透過する光軸（△ｎ２方向）を有す
ることに基づいてその△ｎ１方向の光軸にて強く散乱さ
れた光成分の前記吸収軸を介した吸収効率が向上し、透
過軸方向の光成分は影響を受け難い。その結果、透過軸
を介した透過光の含有割合が高まり偏光度を向上させう
ることより光透過率と耐熱性に優れる偏光フィルムの構
成にて偏光度の向上を図りコントラストを高めることが
できる。According to the present invention, the absorption of a light component having a vibration plane in the direction of the absorption axis and the transmission of a light component having a vibration plane in the direction of the transmission axis, which are exhibited by the absorption type dichroic material in the minute region, are achieved. In this case, the linearly polarized light is obtained through the optical axis (in the direction of △ n1) where the birefringent material in the minute region strongly scatters the linearly polarized light and the optical axis (in the direction of △ n2) through which the linearly polarized light is efficiently transmitted. Based on this, the absorption efficiency of the light component strongly scattered in the optical axis in the Δn1 direction through the absorption axis is improved, and the light component in the transmission axis direction is hardly affected. As a result, the content ratio of the transmitted light through the transmission axis is increased, and the degree of polarization can be improved. Therefore, the degree of polarization can be improved and the contrast can be increased with the configuration of the polarizing film having excellent light transmittance and heat resistance.
【０００７】前記において吸収型二色性材料の吸収軸と
複屈折性材料の直線偏光を強く散乱する光軸とが平行に
ある場合にはその散乱による当該吸収効率が最高とな
り、かつ吸収型二色性材料の透過軸と複屈折性材料の直
線偏光を散乱し難くてそれを効率よく透過する光軸とが
対応して平行となる結果、より偏光度の高い偏光を得る
ことができる。従って黒表示でのコントラストと白表示
での明るさに優れ、良視認性で耐熱性等の耐久性に優れ
る液晶表示装置等を形成することができる。In the above, when the absorption axis of the absorption type dichroic material and the optical axis of the birefringent material that strongly scatter linearly polarized light are parallel, the absorption efficiency due to the scattering is the highest, and the absorption type dichroic material has the highest absorption efficiency. As a result, the transmission axis of the chromatic material and the optical axis of the birefringent material, which hardly scatter linearly polarized light and efficiently transmit the same, are parallel to each other, so that polarized light with a higher degree of polarization can be obtained. Therefore, it is possible to form a liquid crystal display device or the like which is excellent in contrast in black display and brightness in white display, and has excellent visibility and durability such as heat resistance.
【０００８】[0008]
【発明の実施形態】本発明による偏光フィルムは、ポリ
マーからなる透光性フィルム中にそのポリマーとは異種
の材料からなる微小領域を分散含有してなり、その微小
領域が５０℃以上の加熱時に液晶化する複屈折性材料と
その液晶化温度で二色性を喪失しない吸収型二色性材料
との混合層からなるものである。その例を図１に示し
た。１が透光性フィルム、２が微小領域で、２１がその
複屈折性材料、２２がその吸収型二色性材料である。BEST MODE FOR CARRYING OUT THE INVENTION The polarizing film according to the present invention comprises a light-transmitting film made of a polymer in which fine regions made of a material different from the polymer are dispersed and contained, and the fine regions are heated at 50 ° C. or more. It is composed of a mixed layer of a birefringent material to be converted into a liquid crystal and an absorption type dichroic material that does not lose dichroism at the liquid crystal formation temperature. An example is shown in FIG. 1 is a translucent film, 2 is a minute region, 21 is the birefringent material, and 22 is the absorption type dichroic material.
【０００９】透光性フィルムを形成するポリマーとして
は、光を透過する適宜なポリマーの１種又は２種以上を
用いることができ特に限定はない。ちなみにその例とし
てはポリエステル系樹脂、ポリスチレンやアクリロニト
リル・スチレン共重合体（ＡＳポリマー類）の如きスチ
レン系樹脂、ポリエチレンやポリプロピレン、エチレン
・プロピレン共重合体やシクロ系ないしノルボルネン構
造を有するポリオレフィンの如きオレフィン系樹脂やカ
ーボネート系樹脂、アクリル系樹脂や塩化ビニル系樹
脂、セルロース系樹脂やアミド系樹脂があげられる。As the polymer forming the light-transmitting film, one or two or more of suitable polymers transmitting light can be used, and there is no particular limitation. Examples include polyester resins, styrene resins such as polystyrene and acrylonitrile-styrene copolymers (AS polymers), olefins such as polyethylene, polypropylene, ethylene-propylene copolymers, and polyolefins having a cyclo- or norbornene structure. Resins, carbonate resins, acrylic resins, vinyl chloride resins, cellulose resins and amide resins.
【００１０】またイミド系樹脂やスルホン系樹脂、ポリ
エーテルスルホン系樹脂やポリエーテルエーテルケトン
系樹脂、ポリフェニレンスルフィド系樹脂やビニルアル
コール系樹脂、塩化ビニリデン系樹脂やビニルブチラー
ル系樹脂、アリレート系樹脂やポリオキシメチレン系樹
脂、シリコーン系樹脂やウレタン系樹脂、それら熱可塑
性ポリマーのブレンド物、あるいはフェノール系やメラ
ミン系、アクリル系やウレタン系、ウレタンアクリル系
やエポキシ系やシリコーン系等の熱硬化型ないし紫外線
硬化型のポリマーなども透光性フィルムの形成に用いう
る。In addition, imide resins, sulfone resins, polyethersulfone resins, polyetheretherketone resins, polyphenylene sulfide resins, vinyl alcohol resins, vinylidene chloride resins, vinyl butyral resins, arylate resins, Oxymethylene-based resins, silicone-based resins, urethane-based resins, blends of these thermoplastic polymers, or thermosetting or ultraviolet rays such as phenol-based, melamine-based, acrylic-based, urethane-based, urethane-acrylic-based, epoxy-based, and silicone-based resins Curable polymers and the like can also be used for forming the light-transmitting film.
【００１１】透光性フィルムを形成するポリマーは、成
形歪み等による配向複屈折を生じにくいものであっても
よいし（等方性ポリマー）、生じやすいもであってもよ
い（異方性ポリマー）。可視光域での透明性に優れるポ
リマーが好ましく用いうる。また耐熱性や偏光フィルム
への加工性等の点より好ましく用いうるポリマーは、ガ
ラス転移温度が５０℃以上、就中８０℃以上、特に１２
０℃以上のポリマー、殊に加重撓み温度が８０℃以上
で、かつガラス転移温度が１１０℃以上、就中１１５℃
以上、特に１２０℃以上の熱可塑性ポリマーである。な
お前記の加重撓み温度は、ＪＩＳ Ｋ ７２０７に準
じ、１８１．４Ｎ／cm２の曲げ応力を加熱浴中の高さ１
０mmの試験片に加えながら２℃／分で伝熱媒体を昇温さ
せ、試験片の撓み量が０．３２mmに達したときの伝熱媒
体の温度にて定義される。The polymer forming the light-transmitting film may be one that is unlikely to cause alignment birefringence due to molding distortion or the like (isotropic polymer) or one that is likely to cause it (anisotropic polymer). ). A polymer having excellent transparency in the visible light region can be preferably used. Further, a polymer which can be preferably used from the viewpoint of heat resistance and processability into a polarizing film has a glass transition temperature of 50 ° C. or higher, particularly 80 ° C. or higher, and particularly 12 ° C. or higher.
0 ° C. or higher polymer, in particular, a weight deflection temperature of 80 ° C. or higher, and a glass transition temperature of 110 ° C. or higher, especially 115 ° C.
The above is a thermoplastic polymer having a temperature of 120 ° C. or more. The weight deflection temperature was 181.4 N / cm 2 according to JIS K 7207.
The temperature of the heat transfer medium is raised at a rate of 2 ° C./min while being added to the test piece of 0 mm, and is defined by the temperature of the heat transfer medium when the amount of deflection of the test piece reaches 0.32 mm.
【００１２】一方、微小領域を形成する複屈折性材料と
しては、５０℃以上、就中７５℃以上、特に１００℃以
上の加熱温度で溶融して液晶状態を呈する適宜な光透過
性のものを１種又は２種以上用いうる。斯かる複屈折性
材料を用いることにより、その加熱液晶化による配向状
態を冷却固定して透光性フィルム中に複屈折による屈折
率異方性の微小領域を形成でき、透光性フィルムと微小
領域を形成する屈折率異方性の複屈折性材料との屈折率
差に基づいて直線偏光の散乱異方性を示す耐熱性の偏光
フィルムを形成することができる。On the other hand, as the birefringent material forming the minute region, an appropriate light transmissive material which melts at a heating temperature of 50 ° C. or more, especially 75 ° C. or more, particularly 100 ° C. or more to exhibit a liquid crystal state is used. One or more kinds may be used. By using such a birefringent material, it is possible to cool and fix the alignment state by the heating liquid crystallization and form a minute region having a birefringent refractive index anisotropy in the translucent film. A heat-resistant polarizing film exhibiting linearly polarized light scattering anisotropy can be formed based on the difference in refractive index between the birefringent material having the refractive index anisotropy and the birefringent material forming the region.
【００１３】ちなみに前記複屈折性材料の例としては、
加熱溶融時にネマチック相やスメクチック相等の適宜な
液晶状態を呈する主鎖型や側鎖型等の液晶型熱可塑性ポ
リマーなどがあげられる。粒径分布の均一性に優れる微
小領域の形成性や熱的安定性、フィルムへの成形性や配
向処理の容易性などの点より好ましく用いうる液晶型熱
可塑性ポリマーは、重合度が８以上、就中１０以上、特
に１５〜５０００のものである。Incidentally, examples of the birefringent material include:
A liquid crystal type thermoplastic polymer such as a main chain type or a side chain type, which exhibits an appropriate liquid crystal state such as a nematic phase or a smectic phase at the time of heating and melting, may be used. The liquid crystal type thermoplastic polymer which can be preferably used in view of the formability and thermal stability of the fine region excellent in the uniformity of the particle size distribution, the moldability into a film and the ease of the alignment treatment, has a degree of polymerization of 8 or more, In particular, it is 10 or more, especially 15 to 5000.
【００１４】また上記した耐熱性や屈折率異方性の制御
性等の点より複屈折性材料として好ましく用いうる液晶
型熱可塑性ポリマーは、ガラス転移温度が５０℃以上、
就中８０℃以上で、併用の透光性フィルムを形成するポ
リマーのガラス転移温度よりも低い温度域でネマチック
液晶相を呈するものである。ちなみにその具体例として
は、下記の一般式で表されるモノマー単位を有する側鎖
型の液晶型熱可塑性ポリマーなどがあげられる。A liquid crystal type thermoplastic polymer which can be preferably used as a birefringent material in view of the above-mentioned heat resistance and controllability of refractive index anisotropy has a glass transition temperature of 50 ° C. or more.
In particular, it exhibits a nematic liquid crystal phase in a temperature range of 80 ° C. or higher and lower than the glass transition temperature of the polymer forming the combined light-transmitting film. Incidentally, specific examples thereof include a liquid crystal type thermoplastic polymer of a side chain having a monomer unit represented by the following general formula.
【００１５】一般式： General formula:
【００１６】前記の一般式においてＸは、液晶型熱可塑
性ポリマーの主鎖を形成する骨格基であり、線状や分岐
状や環状等の適宜な連結鎖にて形成されていてよい。ち
なみにその例としては、ポリアクリレート類やポリメタ
クリレート類、ポリ−α−ハロアクリレート類やポリ−
α−シアノアクリレート類、ポリアクリルアミド類やポ
リアクリロニトリル類、ポリメタクリロニトリル類やポ
リアミド類、ポリエステル類やポリウレタン類、ポリエ
ーテル類やポリイミド類、ポリシロキサン類などがあげ
られる。In the above general formula, X is a skeletal group forming the main chain of the liquid crystal type thermoplastic polymer, and may be formed by an appropriate connecting chain such as linear, branched or cyclic. Incidentally, examples thereof include polyacrylates and polymethacrylates, poly-α-haloacrylates and poly-
α-cyanoacrylates, polyacrylamides, polyacrylonitriles, polymethacrylonitriles, polyamides, polyesters, polyurethanes, polyethers, polyimides, polysiloxanes, and the like.
【００１７】またＹは、主鎖より分岐するスペーサ基で
あり、偏光フィルムの形成性などの点より好ましいスペ
ーサ基Ｙは、例えばエチレンやプロピレン、ブチレンや
ペンチレン、ヘキシレンやオクチレン、デシレンやウン
デシレン、ドデシレンやオクタデシレン、エトキシエチ
レンやメトキシブチレンなどである。Y is a spacer group branched from the main chain. Preferred spacer groups Y in terms of, for example, the formability of a polarizing film are ethylene, propylene, butylene and pentylene, hexylene and octylene, decylene, undecylene, and dodecylene. And octadecylene, ethoxyethylene and methoxybutylene.
【００１８】一方、Ｚはネマチック配向性を付与するメ
ソゲン基であり、下記の化合物などがあげられる。 On the other hand, Z is a mesogenic group for imparting nematic orientation, and examples thereof include the following compounds.
【００１９】前記の化合物における末端置換基Ａは、例
えばシアノ基やアルキル基、アルケニル基やアルコキシ
基、オキサアルキル基や水素の１個以上がフッ素又は塩
素にて置換されたハロアルキル基やハロアルコキシ基や
ハロアルケニル基などの適宜なものであってよい。The terminal substituent A in the above compound is, for example, a cyano group, an alkyl group, an alkenyl group or an alkoxy group, an oxaalkyl group or a haloalkyl group or a haloalkoxy group in which at least one of hydrogen is substituted by fluorine or chlorine. Or a suitable one such as a haloalkenyl group.
【００２０】前記においてスペーサ基Ｙとメソゲン基Ｚ
はエーテル結合、すなわち−Ｏ−を介して結合していて
もよい。またメソゲン基Ｚにおけるフェニル基は、その
１個又は２個の水素がハロゲンで置換されていてもよ
く、その場合、ハロゲンとしては塩素又はフッ素が好ま
しい。In the above, the spacer group Y and the mesogen group Z
May be linked via an ether bond, that is, -O-. In the phenyl group in the mesogen group Z, one or two hydrogens may be substituted with a halogen. In this case, the halogen is preferably chlorine or fluorine.
【００２１】上記したネマチック配向性で側鎖型の液晶
型熱可塑性ポリマーは、前記一般式で表されるモノマー
単位を有するホモポリマーやコポリマー等の適宜な熱可
塑性ポリマーであればよく、就中モノドメイン配向性に
優れるものが好ましい。The nematic alignment side chain type liquid crystal type thermoplastic polymer may be any suitable thermoplastic polymer such as a homopolymer or a copolymer having a monomer unit represented by the above general formula. Those having excellent domain orientation are preferred.
【００２２】他方、微小領域を形成する吸収型二色性材
料としては、併用の複屈折性材料を液晶化する際にその
加熱温度で二色性を喪失しない耐熱性のものが用いられ
る。斯かる吸収型二色性材料を用いることにより、複屈
折性材料を加熱液晶化して配向処理する際にその吸収型
二色性材料も配向させてその二色性による透過軸と吸収
軸に基づて直線偏光を透過する偏光フィルムを形成する
ことができる。前記の液晶化温度で分解や変質等にて二
色性を喪失するものやヨウ素の如く昇華しやすいもので
は良好な偏光機能を有するものの形成が困難である。On the other hand, as the absorption type dichroic material that forms the minute region, a heat-resistant material that does not lose dichroism at the heating temperature when a combined birefringent material is converted into a liquid crystal is used. By using such an absorption type dichroic material, when the birefringent material is converted into a liquid crystal by heating and subjected to an alignment treatment, the absorption type dichroism material is also aligned, and the dichroic material is oriented based on the transmission axis and the absorption axis. Thus, a polarizing film that transmits linearly polarized light can be formed. It is difficult to form a material having a good polarization function if the material loses dichroism due to decomposition or deterioration at the liquid crystal formation temperature or easily sublimates such as iodine.
【００２３】従って前記の吸収型二色性材料としては、
例えば上記した特開昭６２−１２３４０５号公報などに
記載された所定の耐熱性を有する適宜なものを１種又は
２種以上用いうる。偏光度に優れるものを得る点などよ
り好ましく用いうる吸収型二色性材料は、二色比が３以
上、就中６以上、特に９以上となる吸収波長帯を可視光
域に一箇所又は二箇所以上有する色素である。その色素
の例としては、アゾ系やペリレン系、アントラキノン系
やそれらの混合系等からなる特開昭５４−７６１７１号
公報に記載のものなどがあげられ通例、非水溶性であ
る。カラー偏光板もそのカラー特性に見合った吸収波長
を有する二色性色素を用いることで形成でき、２種以上
の二色性色素を併用して可視光の全域で吸収特性を示す
ニュートラルグレーの偏光板も形成することができる。Therefore, as the above-mentioned absorption type dichroic material,
For example, one or more suitable materials having a predetermined heat resistance described in JP-A-62-123405 described above can be used. Absorption-type dichroic materials that can be used more preferably, for example, in order to obtain a material having an excellent degree of polarization, have an absorption wavelength band having a dichroic ratio of 3 or more, particularly 6 or more, and particularly 9 or more in one or two positions in the visible light region. It is a dye having more than one location. Examples of the dye include azo, perylene, anthraquinone and mixtures thereof described in JP-A-54-76171, and are generally water-insoluble. A color polarizing plate can also be formed by using a dichroic dye having an absorption wavelength commensurate with its color characteristics, and a neutral gray polarized light that exhibits absorption characteristics over the entire visible light range by using two or more dichroic dyes in combination. Plates can also be formed.
【００２４】前記の二色比は、二色性色素の評価に用い
られる一般的な方法に基づく。すなわち該当の色素を適
宜な液晶、例えば市販の液晶（メルク社製、Ｅ−７）に
溶解させその溶液を用いてホモジニアス配向の液晶セル
を形成し、そのセルの偏光吸収スペクトルを測定してそ
のスペクトルにおける吸収極大波長での吸収二色比に基
づく。斯かる方法は、吸収型二色性材料の二色比が分子
自体の吸収二色性に加えてその液晶中での配向性が影響
することより、液晶中での配向性も加味した結果の得ら
れることを目的とする。The dichroic ratio is based on a general method used for evaluating dichroic dyes. That is, the dye is dissolved in an appropriate liquid crystal, for example, a commercially available liquid crystal (manufactured by Merck, E-7), and a homogenous liquid crystal cell is formed using the solution, and the polarization absorption spectrum of the cell is measured. Based on the absorption dichroic ratio at the absorption maximum wavelength in the spectrum. Such a method, the dichroic ratio of the absorption type dichroic material, in addition to the absorption dichroism of the molecule itself, because the orientation in the liquid crystal influences, as a result of taking into account the orientation in the liquid crystal It is intended to be obtained.
【００２５】本発明による偏光フィルムは、図例の如く
複屈折性材料２１と吸収型二色性材料２２との混合層か
らなる微小領域２を透光性フィルム１の中に分散含有す
るものである。その形成は例えば、透光性フィルムを形
成するポリマーの１種又は２種以上を適宜な溶剤で溶解
した溶液と、そのポリマーは溶解しない、ないし溶解し
にくい溶剤で微小領域を形成するための複屈折性材料と
吸収型二色性材料の１種又は２種以上を溶解した溶液と
を混合して、透光性フィルムを形成するポリマー中に当
該複屈折性材料と吸収型二色性材料を含む混合層が相分
離により微小領域の状態で分散したフィルムを形成した
後、必要に応じ適宜な配向処理で複屈折性材料と吸収型
二色性材料を配向させる方法などにて行うことができ
る。The polarizing film according to the present invention is such that, as shown in the figure, the light-transmissive film 1 contains minute regions 2 composed of a mixed layer of a birefringent material 21 and an absorptive dichroic material 22. is there. For example, the formation is performed by using a solution in which one or two or more polymers forming the light-transmitting film are dissolved in an appropriate solvent, and a solution for forming the microscopic region using a solvent in which the polymer is insoluble or hardly soluble. The birefringent material and the absorbing dichroic material are mixed in a polymer forming a light-transmitting film by mixing a refractive material and a solution in which one or more of the absorbing dichroic materials are dissolved. After forming a film in which the mixed layer containing is dispersed in the state of a minute region by phase separation, it can be performed by a method of orienting the birefringent material and the absorption type dichroic material by an appropriate alignment treatment as necessary. .
【００２６】前記では異種の溶剤による相溶性の相違を
利用して相分離を生じさせる方法をあげたが、偏光フィ
ルムの形成方法はそれに限定されずその形成には当該微
小領域を形成できる適宜な方法を採ることができる。従
って当該微小領域を分散含有する透光性フィルムの形成
には例えばキャスティング法や押出成形法、射出成形法
やロール成形法、流延成形法などの適宜な方式を適用す
ることができる。In the above description, a method of causing phase separation by utilizing the difference in compatibility between different solvents has been described. However, the method of forming the polarizing film is not limited to this, and the formation of the polarizing film is not limited to the above method. A method can be adopted. Therefore, an appropriate method such as a casting method, an extrusion molding method, an injection molding method, a roll molding method, a casting method, or the like can be applied to the formation of the light-transmitting film containing the minute regions dispersed therein.
【００２７】微小領域の均等分布性に優れる偏光フィル
ムを得る点などよりは、前記した相分離方式による混合
液をキャスティング法や流延成形法等にて製膜する方式
が好ましい。その場合、溶剤の組合せや混合液の粘度、
混合液展開層の乾燥速度などにより微小領域の大きさや
分布性などを制御することができる。ちなみに微小領域
の小面積化には混合液の低粘度化や混合液展開層の乾燥
速度の急速化などが有利である。From the viewpoint of obtaining a polarizing film having excellent uniform distribution of fine regions, it is preferable to form a mixed solution by the above-mentioned phase separation method by a casting method or a casting method. In that case, the combination of solvents and the viscosity of the mixture,
The size and distribution of the minute region can be controlled by the drying speed of the mixed liquid developing layer. Incidentally, in order to reduce the area of the minute region, it is advantageous to lower the viscosity of the mixed liquid and to increase the drying rate of the mixed liquid developing layer.
【００２８】透光性フィルムの厚さは、配向処理性やフ
ィルム強度、吸収型二色性材料の吸収係数に基づく偏光
性能などの点より適宜に決定することができる。一般に
は、１μm〜３mm、就中５μm〜１mm、特に１０〜５００
μmの厚さとされる。なおフィルムの形成に際しては例
えば分散剤や界面活性剤、紫外線吸収剤や難燃剤、酸化
防止剤などの適宜な添加剤を配合することができる。The thickness of the light-transmitting film can be appropriately determined from the viewpoints of alignment processing properties, film strength, and polarization performance based on the absorption coefficient of the absorption type dichroic material. Generally, 1 μm to 3 mm, especially 5 μm to 1 mm, especially 10 to 500
μm thickness. When forming the film, appropriate additives such as a dispersant, a surfactant, an ultraviolet absorber, a flame retardant, and an antioxidant can be added.
【００２９】前記した微小領域を形成する複屈折性材料
と吸収型二色性材料の必要に応じての配向処理は、それ
らの配向状態のバラツキを少なくして複屈折性材料から
なる領域の各光軸方向における屈折率を制御すること、
及び微小領域の吸収型二色性材料による透過軸の一致性
と吸収軸の一致性を向上させることを目的とする。斯か
る配向処理には、例えば一軸や二軸、逐次二軸やＺ軸等
による延伸処理方式や圧延方式、ガラス転移温度又は液
晶転移温度以上の温度で電場又は磁場を印加して急冷し
配向を固定化する方式や製膜時に流動配向させる方式、
等方性ポリマーの僅かな配向に基づいて複屈折性材料と
吸収型二色性材料を自己配向させる方式などの適宜な方
式の１種又は２種以上を用いるができる。従って得られ
た偏光フィルムは、延伸フィルムであってもよいし非延
伸フィルムであってもよい。The birefringent material and the absorption type dichroic material which form the above-mentioned minute regions are subjected to an alignment treatment as required to reduce the variation in their alignment state and to make each region of the birefringent material smaller. Controlling the refractive index in the optical axis direction,
It is another object of the present invention to improve the coincidence of the transmission axis and the absorption axis of the absorption type dichroic material in the minute area. Such alignment treatment, for example, uniaxial or biaxial, sequential biaxial or Z-axis stretching processing method and rolling method, quenching by applying an electric field or a magnetic field at a temperature equal to or higher than the glass transition temperature or liquid crystal transition temperature, and the alignment is performed. A method of immobilization, a method of flow orientation during film formation,
One or more appropriate methods such as a method of self-orienting the birefringent material and the absorbing dichroic material based on the slight orientation of the isotropic polymer can be used. Therefore, the obtained polarizing film may be a stretched film or a non-stretched film.
【００３０】前記において複屈折性材料が液晶型熱可塑
性ポリマーからなる場合には、例えば透光性フィルム中
に微小領域として分散分布する液晶型熱可塑性ポリマー
がネマチック相等の目的とする液晶相を呈する温度に加
熱して溶融させ、それを配向規制力の作用下に配向させ
たのち液晶転移温度未満に急冷して配向状態を固定化す
る方式などにても行うことができる。微小領域を形成す
る液晶型熱可塑性ポリマーの配向状態は、可及的にモノ
ドメイン状態にあることが光学特性のバラツキ防止など
の点より好ましい。When the birefringent material comprises a liquid crystal thermoplastic polymer in the above, for example, the liquid crystal thermoplastic polymer dispersed and distributed as fine regions in the translucent film exhibits a desired liquid crystal phase such as a nematic phase. It can also be carried out by heating to a temperature and melting it, orienting it under the action of an alignment regulating force, and then quenching it below the liquid crystal transition temperature to fix the alignment state. The orientation state of the liquid crystal type thermoplastic polymer forming the minute region is preferably in a mono-domain state as much as possible from the viewpoint of preventing variations in optical characteristics.
【００３１】前記した液晶型熱可塑性ポリマーの配向規
制力としては、例えば透光性フィルムを適宜な倍率で延
伸処理する方式による延伸力やフィルム形成時のシェア
リング力、電界や磁界などの、液晶型熱可塑性ポリマー
を配向させうる適宜な規制力を適用でき、その１種又は
２種以上の規制力を作用させて液晶型熱可塑性ポリマー
の配向処理を行うことができる。斯かる液晶型熱可塑性
ポリマーの配向処理にて通例、吸収型二色性材料の配向
処理も達成することができる。なお速やかに配向処理を
完了する点よりは一軸延伸方式等の大きな外力を付加で
きる方式が好ましい。As the alignment regulating force of the liquid crystal type thermoplastic polymer, for example, a stretching force by a method of stretching a light-transmitting film at an appropriate magnification, a sharing force at the time of film formation, an electric field and a magnetic field, etc. An appropriate regulating force capable of orienting the type thermoplastic polymer can be applied, and the liquid crystal type thermoplastic polymer can be oriented by applying one or two or more kinds of regulating force. Usually, the alignment treatment of the liquid crystal type thermoplastic polymer can also achieve the alignment treatment of the absorption type dichroic material. Note that a system that can apply a large external force, such as a uniaxial stretching system, is more preferable than a point where the alignment treatment is completed quickly.
【００３２】従って偏光フィルムにおける微小領域以外
の透光性フィルム部分は、複屈折性を示してもよいし、
等方性であってもよい。偏光フィルムの全体が複屈折性
を示すものは、フィルム形成用のポリマーに配向複屈折
性のものを用いて上記した製膜過程における分子配向な
どにより得ることができ、必要に応じ例えば延伸処理等
の公知の配向手段を加えて複屈折性を付与ないし制御す
ることができる。また微小領域以外の部分が等方性の偏
光フィルムは、例えばフィルム形成用のポリマーに等方
性のものを用いて、そのフィルムを当該ポリマーのガラ
ス転移温度以下の温度領域で延伸処理する方式などによ
り得ることができる。Therefore, the light-transmitting film portion other than the minute region in the polarizing film may exhibit birefringence,
It may be isotropic. The polarizing film as a whole exhibits birefringence, can be obtained by molecular orientation in the above-described film forming process using a polymer for film formation having an orientation birefringence, and if necessary, for example, stretching treatment or the like. The birefringence can be imparted or controlled by adding known orientation means. In addition, a polarizing film having an isotropic portion other than the minute region is, for example, a method of stretching the film in a temperature region equal to or lower than the glass transition temperature of the polymer by using an isotropic polymer for forming the film. Can be obtained by
【００３３】好ましい偏光フィルムは、微小領域を形成
する複屈折性材料が透光性フィルムと０．０３以上、就
中０．０５以上、特に０．１０以上の最大屈折率差△ｎ
１となる光軸と、その光軸に直交して透光性フィルムと
の屈折率差△ｎ２が等しく、かつその△ｎ２が前記△ｎ
１の５０％以下、就中３０％以下、特に０．０３以下の
可及的に小さいものである二方向の光軸を有するもので
ある。これにより最大屈折率差△ｎ１を示す光軸方向に
対応する偏光が強く散乱され、屈折率差△ｎ２を示す光
軸方向に対応する偏光はその偏光状態を維持して効率よ
く透過し、斯かる散乱異方性に基づいて偏光度と光透過
率に優れる偏光フィルムとすることができる。A preferred polarizing film has a maximum refractive index difference Δn of 0.03 or more, more preferably 0.05 or more, especially 0.10 or more than that of the light transmitting film.
1 and the refractive index difference Δn2 between the optical axis perpendicular to the optical axis and the translucent film, and Δn2 is the Δn
It has a bidirectional optical axis which is as small as 50% or less, especially 30% or less, especially 0.03 or less of 1. Thereby, the polarized light corresponding to the optical axis direction indicating the maximum refractive index difference Δn1 is strongly scattered, and the polarized light corresponding to the optical axis direction indicating the refractive index difference Δn2 is transmitted efficiently while maintaining its polarization state. Based on the scattering anisotropy, a polarizing film having excellent polarization degree and light transmittance can be obtained.
【００３４】また偏光度と光透過率に優れる偏光フィル
ムを得る点よりは、微小領域を形成する吸収型二色性材
料の吸収軸と複屈折性材料の△ｎ１を示す光軸方向とが
可及的に平行関係となるように配向していることが好ま
しい。これにより前記の△ｎ１を示す光軸方向に対応し
て強く散乱された偏光がその散乱による光路長の増大で
吸収に関する見かけ厚さが増大し吸収型二色性材料の吸
収軸を介して効率よく吸収することができる。In addition, rather than obtaining a polarizing film excellent in the degree of polarization and light transmittance, the absorption axis of the absorption type dichroic material forming the minute region and the direction of the optical axis indicating Δn1 of the birefringent material are better. Preferably, they are oriented so as to be as parallel as possible. As a result, the strongly scattered polarized light corresponding to the direction of the optical axis indicating Δn1 increases the apparent path length due to the increase in the optical path length due to the scattering, and the efficiency increases through the absorption axis of the absorption type dichroic material. Can be well absorbed.
【００３５】前記した散乱と吸収による偏光度と光透過
率の関係は以下のモデルにて説明することができる。す
なわち吸収型二色性材料が一方向に配向した偏光板の平
行透過率Ｘと偏光度Ｐは、その二つの主透過率を第一主
透過率Ｋ１（透過率が最大となる方向）、第二主透過率
Ｋ２（透過率が最小となる方向）として、Ｘ＝０．５×
（Ｋ１２＋Ｋ２２）、Ｐ＝（Ｋ１−Ｋ２）／（Ｋ１＋Ｋ
２）で表すことができる。その場合に本発明においては
吸収型二色性材料による吸収が吸収係数と光路長に比例
することより、第一主透過率Ｋ１（△ｎ２を示す光軸方
向に対応する直線偏光透過率）は変わらないとし、△ｎ
１を示す光軸方向に対応して散乱された偏光の光路長の
増大をα倍、かつ散乱による偏光の解消はないものとし
て第二主透過率Ｋ２’（△ｎ１を示す光軸方向に対応す
る直線偏光透過率）はＫ２’＝１０αｌｏｇＫ２となる
ことから、当該平行透過率Ｘ’と偏光度Ｐ’は、Ｘ’＝
０．５×（Ｋ１２＋Ｋ２’２）、Ｐ’＝（Ｋ１−Ｋ
２’）／（Ｋ１＋Ｋ２’）にて表されることとなる。The relationship between the degree of polarization due to scattering and absorption and the light transmittance can be explained by the following model. That is, the parallel transmittance X and the degree of polarization P of the polarizing plate in which the absorption type dichroic material is oriented in one direction are obtained by dividing the two main transmittances into the first main transmittance K1 (the direction in which the transmittance becomes maximum) and the second main transmittance. X = 0.5 × as the main transmittance K2 (the direction in which the transmittance becomes minimum)
(K1 2 + K2 2), P = (K1-K2) / (K1 + K
It can be represented by 2). In that case, in the present invention, since the absorption by the absorption type dichroic material is proportional to the absorption coefficient and the optical path length, the first main transmittance K1 (the linearly polarized light transmittance corresponding to the optical axis direction indicating Δn2) is: No change, 変 n
The increase in the optical path length of the scattered polarized light corresponding to the optical axis direction indicating α is α times, and the second main transmittance K2 ′ (corresponding to the optical axis direction indicating △ n1) K2 ′ = 10 αlog K2, the parallel transmittance X ′ and the degree of polarization P ′ are X ′ =
0.5 × (K1 2 + K2 ′ 2 ), P ′ = (K1−K
2 ′) / (K1 + K2 ′).
【００３６】よってα倍の光路長の増大にて偏光度や平
行透過率を向上させることができる。ちなみに平行透過
率０．３２１、偏光度０．９０、Ｋ１：０．８０、Ｋ
２：０．０４の特性を示す偏光板の形成に用いた吸収型
二色性材料を用いて本発明による偏光フィルムを形成し
た場合、当該αを２倍として前記式より平行透過率が
０．３２０で偏光度が０．９９６のものとすることがで
きる。また偏光度０．９０を維持した場合には色素濃度
を薄くして平行透過率が０．４０６のものとすることが
できる。Thus, the degree of polarization and the parallel transmittance can be improved by increasing the optical path length by α times. Incidentally, the parallel transmittance is 0.321, the degree of polarization is 0.90, K1: 0.80, K
When the polarizing film according to the present invention is formed using the absorption type dichroic material used for forming the polarizing plate exhibiting the characteristic of 2: 0.04, the α is doubled and the parallel transmittance is determined to be 0. At 320, the degree of polarization can be 0.996. When the polarization degree is maintained at 0.90, the dye concentration can be reduced to achieve a parallel transmittance of 0.406.
【００３７】前記の特性は、前記の理論式による計算上
のものであり実際には作業精度等によるＫ１の変化（減
少）や散乱による偏光の解消、表面反射や後方散乱など
で偏光機能は前記式による特性よりも通例の場合、若干
低下する。なお前記式より、散乱による光路長（α）が
大きくなるほど、また吸収型二色性材料の二色比が大き
いほど偏光機能を向上させうることがわかる。なおα
は、上記した△ｎ１を大きくするほど高い数値とするこ
とができる。The above-mentioned characteristics are calculated by the above-mentioned theoretical formula. Actually, the polarization function is changed by the change (decrease) of K1 due to work accuracy and the like, the elimination of polarization due to scattering, the surface reflection and the back scattering, etc. In the usual case, the characteristic is slightly lower than the characteristic according to the equation. From the above equation, it can be seen that the larger the optical path length (α) due to scattering and the larger the dichroic ratio of the absorption type dichroic material, the more the polarization function can be improved. Note that α
Can be set to a higher value as Δn1 is increased.
【００３８】偏光フィルムにおける微小領域は、前記散
乱効果等の均質性などの点より可及的に均等に分散分布
していることが好ましい。微小領域の大きさ、特に散乱
方向である△ｎ１を示す光軸方向の長さは、散乱の強さ
に影響する。可視光域の波長で強く散乱させる点より
は、微小領域の長さを複屈折性材料の△ｎ１を示す光軸
方向に基づいて０．０５〜５００μm、就中０．１〜２
５０μm、特に０．５〜１００μmとすることが好まし
い。斯かる長さが０．０５μm未満では可視光域の光を
散乱させる機能に乏しくなり、５００μmを超えるとフ
ィルム強度が低下したり、微小領域中での複屈折性材料
の配向制御が困難となりやすい。It is preferable that the minute regions in the polarizing film are distributed and distributed as uniformly as possible from the viewpoint of homogeneity such as the scattering effect. The size of the minute region, particularly the length in the optical axis direction indicating Δn1, which is the scattering direction, affects the intensity of scattering. Rather than strongly scattering at wavelengths in the visible light range, the length of the minute region is 0.05 to 500 μm, especially 0.1 to 2, based on the optical axis direction indicating Δn1 of the birefringent material.
It is preferably 50 μm, particularly preferably 0.5 to 100 μm. When the length is less than 0.05 μm, the function of scattering light in the visible light region is poor, and when the length exceeds 500 μm, the film strength is reduced, and it is easy to control the orientation of the birefringent material in the minute region. .
【００３９】前記した微小領域の寸法制御性等の点より
も上記した相分離による偏光フィルムの形成方法が好ま
しい。なお斯かる相分離方法によるとき微小領域は、通
例ドメインの状態で偏光フィルム中に存在するが、その
場合も含めて△ｎ２を示す光軸方向の長さについては特
に限定はない。偏光フィルム中に占める微小領域の割合
は、△ｎ１を示す光軸方向の散乱性などの点より適宜に
決定しうるが、一般にはフィルム強度なども踏まえて
０．１〜９０重量％、就中１〜７０重量％、特に５〜５
０重量％とされる。The method of forming a polarizing film by the above-described phase separation is more preferable than the above-described controllability of the size of the minute region. In addition, when such a phase separation method is used, the minute region usually exists in the polarizing film in a state of a domain, but the length in the optical axis direction indicating Δn2 including the case is not particularly limited. The proportion of the minute area in the polarizing film can be appropriately determined from the viewpoint of scattering in the optical axis direction indicating Δn1, but is generally 0.1 to 90% by weight in consideration of the film strength and the like. 1 to 70% by weight, especially 5 to 5
0% by weight.
【００４０】本発明による偏光フィルムは、従来の偏光
子に準じた各種の目的に用いることができる。就中、耐
熱性に優れることより屋外使用や車載等を目的とする液
晶表示装置の形成などに好ましく用いることができる。
液晶表示装置は、従来に準じて液晶セルの片側又は両側
に偏光フィルムを配置することにより形成することがで
きる。The polarizing film according to the present invention can be used for various purposes according to a conventional polarizer. Especially, since it is excellent in heat resistance, it can be preferably used for forming a liquid crystal display device for outdoor use, vehicle mounting, and the like.
The liquid crystal display device can be formed by disposing a polarizing film on one side or both sides of a liquid crystal cell according to the related art.
【００４１】偏光フィルムは、単層物として用いること
もできるし、同種物又は異種物の２層以上を重畳したも
のとして用いることもできる。重畳に際しては吸収軸が
上下の層で可及的に一致するようにすることが好まし
い。また偏光フィルムは、その片側又は両側に必要に応
じて従来の偏光板に準じた透明保護層を設けて実用に共
することもできるが、薄型化の点よりは透明保護層を設
けることなく用いることが好ましい。本発明による偏光
フィルムは、透明保護層を有しない状態にても耐久性に
優れている。The polarizing film can be used as a single-layered material or as a laminate of two or more layers of the same or different types. At the time of superposition, it is preferable that the absorption axes be as coincident as possible in the upper and lower layers. Further, the polarizing film can be provided with a transparent protective layer according to a conventional polarizing plate on one or both sides thereof, if necessary, for practical use.However, it is used without providing a transparent protective layer from the viewpoint of thinning. Is preferred. The polarizing film according to the present invention has excellent durability even without a transparent protective layer.
【００４２】液晶表示装置の形成に際しては、必要に応
じて液晶セルと偏光フィルムの間に一層又は二層以上の
位相差板を配置することもできる。その場合、偏光フィ
ルムと位相差板を予め接着層等を介し接着積層したもの
として用いることもできる。斯かる接着処理は、液晶表
示装置等の組立効率の向上や光軸のズレ防止、各界面へ
の異物等の侵入防止などを目的とする。接着処理には例
えばホットメルト系や粘着系などの適宜な接着剤を用い
うる。また前記の積層体には位相差板以外の適宜な光学
部品を付加することもできる。従って液晶表示装置で
は、偏光フィルムや位相差板等のその他の光学部品が接
着層を介して液晶セルと接着積層されて一体化している
ことが好ましい。In forming the liquid crystal display device, one or more retardation plates may be disposed between the liquid crystal cell and the polarizing film as necessary. In this case, the polarizing film and the retardation plate may be used in a state where they are bonded and laminated in advance via an adhesive layer or the like. Such an adhesion treatment aims at improving the assembly efficiency of the liquid crystal display device or the like, preventing the optical axis from being displaced, and preventing foreign substances or the like from entering each interface. For the bonding treatment, for example, a suitable adhesive such as a hot-melt type or an adhesive type can be used. Further, an appropriate optical component other than the retardation plate can be added to the laminate. Therefore, in the liquid crystal display device, it is preferable that other optical components such as a polarizing film and a phase difference plate are bonded and laminated to the liquid crystal cell via the bonding layer to be integrated.
【００４３】前記の位相差板としては例えば１／４波長
板や１／２波長板、一軸や二軸等による延伸フィルムタ
イプやさらに厚さ方向にも分子配向させた傾斜配向フィ
ルムタイプ、液晶タイプ、視野角や複屈折による位相差
を補償するタイプ、それらを積層したタイプのものなど
の各種のものを用いうる。また前記の光学部品について
も特に限定はなく、例えば導光板等のバックライトや反
射板、反射防止膜や防眩層、多層膜やコレステリック液
晶層等からなる偏光分離板などの適宜なものであってよ
い。Examples of the retardation plate include a １ ／ wavelength plate, a 波長 wavelength plate, a uniaxially or biaxially stretched film type, an obliquely oriented film type in which molecules are oriented in the thickness direction, and a liquid crystal type. Various types such as a type for compensating a phase difference due to a viewing angle and a birefringence, and a type in which they are laminated can be used. The optical component is not particularly limited, and may be an appropriate one such as a backlight such as a light guide plate, a reflection plate, an antireflection film or an antiglare layer, or a polarization separation plate composed of a multilayer film or a cholesteric liquid crystal layer. May be.
【００４４】[0044]
【実施例】実施例１ ポリビニルアルコール（ＰＶＡ）８５０部(重量部、以
下同じ)を含有する１０重量％水溶液と下式１で表され
る液晶型熱可塑性ポリマー１００部、及び市販の吸収型
二色性色素（Ｍ８６：三井化学社製）５０部を含有する
１０重量％トルエン溶液をホモミキサーにて撹拌混合
し、キャスト法にて厚さ８０μmのフィルムを得た後そ
の水とトルエンの両溶媒を十分に乾燥させたフィルムを
１６０℃で２倍に延伸処理し急冷して偏光フィルムを得
た。EXAMPLE 1 A 10% by weight aqueous solution containing 850 parts (parts by weight, hereinafter the same) of polyvinyl alcohol (PVA), 100 parts of a liquid crystal type thermoplastic polymer represented by the following formula 1, and a commercially available absorption type A 10% by weight toluene solution containing 50 parts of a coloring dye (M86: manufactured by Mitsui Chemicals, Inc.) was stirred and mixed with a homomixer to obtain a film having a thickness of 80 μm by a casting method. Was stretched twice at 160 ° C. and quenched to obtain a polarizing film.
【００４５】式１： Equation 1:
【００４６】前記の偏光フィルムは、ＰＶＡからなる透
光性フィルム中に、当該液晶型熱可塑性ポリマーと当該
吸収型二色性色素の混合物からなる微小領域が分散分布
すると共に、その微小領域中で液晶型熱可塑性ポリマー
と吸収型二色性色素が延伸方向に配向したものであり、
△ｎ１が０．１８で、その光軸に直交する二方向の光軸
における△ｎ２がいずれの場合も０．０１であった。ま
た吸収型二色性色素の吸収軸と液晶型熱可塑性ポリマー
の△ｎ１を示す光軸方向とがほぼ一致していた。さらに
偏光顕微鏡観察による位相差に基づく着色にて、分散分
布する微小領域（液晶型熱可塑性ポリマー）の平均サイ
ズを見積もった結果、液晶型熱可塑性ポリマーの△ｎ１
を示す光軸方向に基づいて約７μmであった。In the polarizing film described above, a fine region comprising a mixture of the liquid crystal type thermoplastic polymer and the absorption type dichroic dye is dispersed and distributed in a translucent film made of PVA. Liquid crystal type thermoplastic polymer and absorption type dichroic dye are oriented in the stretching direction,
△ in n 1 is 0.18, in the two directions of the optical axis perpendicular to the optical axis △ n 2 was 0.01 in any case. Further, the absorption axis of the absorption type dichroic dye and the optical axis direction indicating Δn1 of the liquid crystal type thermoplastic polymer almost coincided. Furthermore, by coloring based on the phase difference by observation with a polarizing microscope, the average size of the minute regions (liquid crystal type thermoplastic polymer) dispersed and distributed was estimated. As a result, Δn1 of the liquid crystal type thermoplastic polymer was obtained.
Was about 7 μm based on the optical axis direction.
【００４７】前記の偏光フィルムについて分光光度計に
よりその吸収極大波長（５１０nm）における平行透過率
と偏光度を調べた。その結果、市販の高透過高偏光度タ
イプの耐熱性染料系偏光板よりも高透過率、かつ高偏光
度であった。The parallel transmittance and the degree of polarization of the above polarizing film at the maximum absorption wavelength (510 nm) were examined by a spectrophotometer. As a result, the transmissivity and the degree of polarization were higher than those of a commercially available high-transmission high-polarization type heat-resistant dye-based polarizing plate.
【図１】実施例の断面図FIG. 1 is a sectional view of an embodiment.
１：透光性フィルム ２：微小領域 ２１：複屈折性材料 ２２：吸収型二色性材料 1: translucent film 2: minute area 21: birefringent material 22: absorption type dichroic material
Claims (10)
のポリマーとは異種の材料からなる微小領域を分散含有
してなり、その微小領域が５０℃以上の加熱時に液晶化
する複屈折性材料とその液晶化温度で二色性を喪失しな
い吸収型二色性材料との混合層からなることを特徴とす
る偏光フィルム。1. A birefringent material comprising a light-transmitting film made of a polymer in which minute regions made of a material different from the polymer are dispersed and contained, and the minute regions become liquid crystal when heated at 50 ° C. or more. A polarizing film comprising a mixed layer with an absorption-type dichroic material that does not lose dichroism at the liquid crystalization temperature.
複屈折性材料が透光性フィルムと０．０３以上の最大屈
折率差△ｎ１となる光軸と、その光軸に直交して透光性
フィルムとの屈折率差△ｎ２が等しく、かつその△ｎ２
が前記△ｎ１の５０％以下である二方向の光軸を有する
偏光フィルム。2. The optical system according to claim 1, wherein the birefringent material forming the minute region has a maximum refractive index difference Δn1 of 0.03 or more with respect to the light-transmitting film and an optical axis perpendicular to the optical axis. The refractive index difference Δn2 from the optical film is equal and the refractive index difference Δn2
Is a polarizing film having optical axes in two directions that is 50% or less of Δn1.
吸収型二色性材料の吸収軸と複屈折性材料の△ｎ１を示
す光軸方向とが平行関係となるように配向してなる偏光
フィルム。3. The polarized light according to claim 2, wherein the absorption axis of the absorption type dichroic material forming the minute region and the optical axis direction indicating Δn1 of the birefringent material have a parallel relationship. the film.
さが複屈折性材料の△ｎ１を示す光軸方向に基づいて
０．０５〜５００μmである偏光フィルム。4. The polarizing film according to claim 2, wherein the length of the minute region is 0.05 to 500 μm based on the optical axis direction indicating Δn1 of the birefringent material.
する複屈折性材料が透光性フィルムを形成するポリマー
のガラス転移温度よりも低い温度域でネマチック液晶相
を呈するガラス転移温度５０℃以上の液晶型熱可塑性ポ
リマーからなる偏光フィルム。5. The glass transition temperature according to claim 1, wherein the birefringent material forming the minute region exhibits a nematic liquid crystal phase in a temperature range lower than the glass transition temperature of the polymer forming the light-transmitting film. A polarizing film comprising the above liquid crystal type thermoplastic polymer.
が加重撓み温度８０℃以上、ガラス転移温度１１０℃以
上の熱可塑性ポリマーからなる偏光フィルム。6. The polarizing film according to claim 1, wherein the light-transmitting film is made of a thermoplastic polymer having a weight deflection temperature of 80 ° C. or higher and a glass transition temperature of 110 ° C. or higher.
する吸収型二色性材料が可視光域に二色比が３以上とな
る少なくとも一箇所の吸収波長帯を有する色素からなる
偏光フィルム。7. The polarizing film according to claim 1, wherein the absorption type dichroic material forming the minute region is a dye having at least one absorption wavelength band having a dichroic ratio of 3 or more in a visible light region. .
に記載の偏光フィルムを有することを特徴とする液晶表
示装置。8. A liquid crystal cell on one or both sides.
A liquid crystal display device comprising the polarizing film according to item 1.
ルムの間に一層又は二層以上の位相差板を有する液晶表
示装置。9. The liquid crystal display device according to claim 8, comprising one or more phase retarders between the liquid crystal cell and the polarizing film.
ムが接着層を介して液晶セル又は位相差板と接着積層さ
れてなる液晶表示装置。10. The liquid crystal display device according to claim 8, wherein the polarizing film is adhered and laminated to a liquid crystal cell or a retardation plate via an adhesive layer.
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|---|---|---|---|
| JP2001000331A JP4614407B2 (en) | 2001-01-05 | 2001-01-05 | Polarizing film and liquid crystal display device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001000331A JP4614407B2 (en) | 2001-01-05 | 2001-01-05 | Polarizing film and liquid crystal display device |
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| Publication Number | Publication Date |
|---|---|
| JP2002207118A true JP2002207118A (en) | 2002-07-26 |
| JP4614407B2 JP4614407B2 (en) | 2011-01-19 |
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|---|---|---|---|
| JP2001000331A Expired - Fee Related JP4614407B2 (en) | 2001-01-05 | 2001-01-05 | Polarizing film and liquid crystal display device |
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| Country | Link |
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