JPH11305038A - Birefringent film - Google Patents

Birefringent film

Info

Publication number
JPH11305038A
JPH11305038A JP10117112A JP11711298A JPH11305038A JP H11305038 A JPH11305038 A JP H11305038A JP 10117112 A JP10117112 A JP 10117112A JP 11711298 A JP11711298 A JP 11711298A JP H11305038 A JPH11305038 A JP H11305038A
Authority
JP
Japan
Prior art keywords
film
plasticizer
stretched
solvent
birefringent
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.)
Pending
Application number
JP10117112A
Other languages
Japanese (ja)
Inventor
Masakatsu Tagami
昌克 田上
Manabu Suezawa
学 末澤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sekisui Chemical Co Ltd
Original Assignee
Sekisui Chemical Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Sekisui Chemical Co Ltd filed Critical Sekisui Chemical Co Ltd
Priority to JP10117112A priority Critical patent/JPH11305038A/en
Publication of JPH11305038A publication Critical patent/JPH11305038A/en
Pending legal-status Critical Current

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  • Liquid Crystal (AREA)
  • Laminated Bodies (AREA)
  • Polarising Elements (AREA)

Abstract

PROBLEM TO BE SOLVED: To provide a birefringent film which has small variances in phase difference value and also has phase difference compensation effect and field angle expansion effect. SOLUTION: This film is obtained by giving a shrinkage force to a drawn film having a 0.30 wt.% or less difference in the presence amount of a solvent or plasticizer, among blocks obtained by dividing the film equally into three along the width. A superior Z-alignment coefficient is given by equally distributing the thickness-directional alignment of the film. The variance in phase difference value is made small and the superior phase difference compensation effect and field angle expansion effect are imparted.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【発明の属する技術分野】本発明は液晶表示装置に代表
される電気光学表示装置に用いられる複屈折フィルムに
関する。
The present invention relates to a birefringent film used for an electro-optical display device represented by a liquid crystal display device.

【従来の技術】近年、携帯用パーソナルコンピュータ
ー、ワープロ、モニター等における表示素子として、大
画面が可能であるとともに軽量且つ薄いという特徴を持
った液晶表示装置が用いられることが多くなってきた。
2. Description of the Related Art In recent years, a liquid crystal display device having a feature of being capable of providing a large screen and being lightweight and thin has been increasingly used as a display element in a portable personal computer, word processor, monitor and the like.

【0002】従来の液晶表示装置は液晶物質の光学異方
性を利用して、電界印加における配向を生じさせること
により光を制御する方法を採っているが、この方法を単
純に利用するだけでは、液晶表示装置は液晶分子による
複屈折で楕円偏光となり、ディスプレイが着色するとい
った問題点があった。
A conventional liquid crystal display device employs a method of controlling light by using an optical anisotropy of a liquid crystal material to generate an alignment upon application of an electric field. However, simply using this method is not sufficient. On the other hand, the liquid crystal display device has a problem that the display becomes colored due to birefringence by liquid crystal molecules and the display is colored.

【0003】この現象を回避し液晶分子の複屈折を補償
する方法として、液晶セルと偏光板との間に高分子の延
伸フィルムからなる位相差補償フィルムを介在させて、
ディスプレイの着色を防止する方法が提案され、現在市
販されているSTN型ディスプレイは殆どこの構成体で
生産されている。
As a method of avoiding this phenomenon and compensating for birefringence of liquid crystal molecules, a retardation compensation film composed of a stretched polymer film is interposed between a liquid crystal cell and a polarizing plate.
Methods have been proposed to prevent coloration of the display, and most commercially available STN-type displays are produced with this construction.

【0004】しかしながら、上記構成体のSTN型ディ
スプレイは、画面を見る角度によって表示色が反転した
り、表示光量が低下するなどの問題があり、多人数の者
が一度に同一表示画面を見ることは困難であった。
[0004] However, the STN type display having the above structure has a problem that a display color is inverted or a display light amount is reduced depending on an angle at which the screen is viewed, so that a large number of persons view the same display screen at a time. Was difficult.

【0005】そこで、この問題を解決すべく視野拡大フ
ィルムを使って視野角を広げる方法が提案されており、
このような視野拡大フィルムとしては、微細なレンズ状
の窪みを設ける通常マイクロレンズシートと呼ばれるも
のや平面方向に配向した分子群と厚さ方向に配向した分
子群が混在してなる複屈折フィルム(特開平5−157
911号公報)等が例示される。
[0005] In order to solve this problem, there has been proposed a method of widening the viewing angle by using a field expansion film.
Examples of such a field-of-view expanding film include a so-called microlens sheet provided with fine lens-shaped depressions, and a birefringent film in which a group of molecules oriented in a plane direction and a group of molecules oriented in a thickness direction are mixed. JP-A-5-157
911) and the like.

【0006】上記複屈折フィルムは、フィルム中の屈折
率を直交軸方向の屈折率nx、それと垂直な屈折率n
y、厚さ方向の屈折率をnzとすると、nx>ny、
(nx−nz)/(nx−ny)=Nz(Nz:Z配向
係数)として0<Nz<1となることを特徴とするもの
であり、理論上液晶分子による複屈折位相差の補償を行
いながら、観察者が良好なコントラストでディスプレイ
を観察することが可能な、一般に視野角と呼ばれている
角度を広げる効果を有する。
In the birefringent film, the refractive index in the film is defined as a refractive index nx in the direction of the orthogonal axis, and a refractive index n perpendicular thereto.
y, if the refractive index in the thickness direction is nz, then nx> ny,
(Nx-nz) / (nx-ny) = Nz (Nz: Z orientation coefficient), where 0 <Nz <1. Theoretically, birefringence phase difference due to liquid crystal molecules is compensated. However, it has an effect of widening an angle generally called a viewing angle, which allows an observer to observe the display with good contrast.

【0007】上記複屈折フィルムの製造方法としては、
押出成形された熱可塑性樹脂をスライスし、厚さ方向に
分子配列したシートを得、それを延伸する製造方法(特
開平2−160204号公報)や、樹脂フィルムを延伸
処理する際に、その片面もしくは両面に収縮性フィルム
を貼合して延伸方向と直交する方向の収縮力を付与する
製造方法(特開平5−157911)等が提案されてい
る。
As a method for producing the above birefringent film,
The extruded thermoplastic resin is sliced to obtain a sheet in which molecules are arranged in the thickness direction, and the sheet is stretched. Alternatively, a production method has been proposed in which a shrinkable film is attached to both surfaces to impart a shrink force in a direction perpendicular to the stretching direction (Japanese Patent Application Laid-Open No. 5-157911).

【0008】しかしながら、前者の方法は、その生産性
に大きな問題があり、安価な複屈折フィルムを得ること
が出来ず、又、後者の方法は、前者のような問題点はな
いものの、収縮力付与時の温度が低い場合や収縮力を付
与する時間が短い場合には、厚み方向の配向が充分でな
く視野拡大効果を発現しないことがあり、又、場合によ
っては面内で均一な収縮が行われず、製品面内の位相差
値がばらつき、ディスプレイに色ムラが発生するといっ
た問題点を有していた。
However, the former method has a major problem in its productivity, so that an inexpensive birefringent film cannot be obtained. In addition, the latter method has no problem as in the former, but has a contraction force. When the temperature at the time of application is low or when the time for applying the contraction force is short, the orientation in the thickness direction may not be sufficient and the visual field enlarging effect may not be exhibited. However, there is a problem in that the phase difference value in the product surface varies, and color unevenness occurs on the display.

【0009】[0009]

【発明が解決しようとする課題】本発明は、上記問題点
に鑑みてなされたものであり、位相差値のバラツキが小
さいとともに優れた位相差補償効果と視野角拡大効果と
を有する複屈折フィルムを提供する。
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has been made in view of the above circumstances, and has a birefringent film having a small variation in retardation value and having an excellent phase difference compensating effect and a wide viewing angle effect. I will provide a.

【0010】[0010]

【課題を解決するための手段】本発明の複屈折フィルム
は、所定方法により製造された延伸フィルムに所定条件
下において収縮力を付与することによって得られた複屈
折フィルムにおいて、上記収縮力を付与する前の延伸フ
ィルムを厚み方向に略三等分割して得られる各ブロック
間における溶剤又は可塑剤の全存在量の差が0.30重
量%以下であることを特徴とする。
A birefringent film according to the present invention is a birefringent film obtained by applying a shrinkage force under predetermined conditions to a stretched film produced by a predetermined method. The difference between the total amount of the solvent or the plasticizer in each block obtained by dividing the stretched film before the stretching into approximately three equal parts in the thickness direction is 0.30% by weight or less.

【0011】先ず、上記延伸フィルムは、熱可塑性樹脂
と可塑剤との混合物又は熱可塑性樹脂を溶剤に溶解後、
この溶液を流延することによってフィルムを得、得られ
たフィルムを一軸延伸することによって得られる。
First, the stretched film is prepared by dissolving a mixture of a thermoplastic resin and a plasticizer or a thermoplastic resin in a solvent,
A film is obtained by casting this solution, and the obtained film is obtained by uniaxially stretching.

【0012】上記熱可塑性樹脂としては、従来から複屈
折フィルムに用いられているものであれば、特に限定は
なく、例えば、セルロース系樹脂、塩化ビニル系樹脂、
ポリカーボネート系樹脂、アクリロニトリル系樹脂、オ
レフィン系樹脂、ポリサルフォン系樹脂、ポリエーテル
サルフォン系樹脂等の熱可塑性樹脂が挙げられる。
The thermoplastic resin is not particularly limited as long as it has been conventionally used for a birefringent film. For example, a cellulose resin, a vinyl chloride resin,
Thermoplastic resins such as polycarbonate-based resins, acrylonitrile-based resins, olefin-based resins, polysulfone-based resins, and polyethersulfone-based resins are exemplified.

【0013】上記熱可塑性樹脂には必要に応じて可塑剤
が添加されるが、可塑剤としては、従来から複屈折フィ
ルムの製造において用いられているものであれば、特に
限定されず、例えば、フタル酸系可塑剤、りん酸系可塑
剤、アジピン酸可塑剤、クエン酸系可塑剤、グリコール
酸系可塑剤等が適用でき、特に、フタル酸ジエチル、フ
タル酸ジブチル等のフタル酸系可塑剤が好適である。
又、2種類以上のこれらの可塑剤を混合して適用しても
よい。
[0013] A plasticizer is added to the above-mentioned thermoplastic resin, if necessary. The plasticizer is not particularly limited as long as it has been conventionally used in the production of a birefringent film. A phthalic acid plasticizer, a phosphoric acid plasticizer, an adipic acid plasticizer, a citric acid plasticizer, a glycolic acid plasticizer, and the like can be applied. Particularly, phthalic acid plasticizers such as diethyl phthalate and dibutyl phthalate can be used. It is suitable.
Further, two or more kinds of these plasticizers may be mixed and applied.

【0014】上記熱可塑性樹脂と上記可塑剤との混合物
又は上記熱可塑性樹脂をこれらを溶解可能な溶剤に溶解
し、得られた溶液をダイコーター、コンマコーター等の
汎用手段を用いて平滑面を有する金属ベルト、フィルム
上に均一に流延し、後乾燥させて溶剤又は可塑剤成分を
一定レベルまで揮発させて、平滑な熱可塑性樹脂フィル
ムを得る。そして、汎用の延伸手段によって、熱可塑性
樹脂フィルムを熱可塑性樹脂のガラス転移点近傍の温度
で一軸延伸して上記延伸フィルムを得る。
A mixture of the above-mentioned thermoplastic resin and the above-mentioned plasticizer or the above-mentioned thermoplastic resin is dissolved in a solvent capable of dissolving them, and the resulting solution is smoothed using a general-purpose means such as a die coater or a comma coater. It is uniformly cast on a metal belt or film having the same and then dried to evaporate a solvent or a plasticizer component to a certain level to obtain a smooth thermoplastic resin film. Then, the thermoplastic resin film is uniaxially stretched by a general-purpose stretching means at a temperature near the glass transition point of the thermoplastic resin to obtain the stretched film.

【0015】ここで、熱可塑性樹脂フィルムを得るに際
して行った乾燥だけでは、熱可塑性樹脂フィルムは、そ
の表層部から中央部となるにしたがって上記溶剤又は可
塑剤の全存在量が増加しており、この溶剤又は可塑剤の
全存在量の不均一が原因となって上記熱可塑性樹脂フィ
ルムはその厚み方向に弾性率に差を生じている(熱可塑
性樹脂フィルムの中央部は低弾性率となっている一方、
熱可塑性樹脂フィルムの表層部は高弾性率となってい
る)。
[0015] Here, only by drying performed when obtaining the thermoplastic resin film, the total amount of the solvent or the plasticizer increases in the thermoplastic resin film from the surface layer portion to the center portion, Due to the non-uniformity of the total amount of the solvent or the plasticizer, the thermoplastic resin film has a difference in elastic modulus in its thickness direction (the central portion of the thermoplastic resin film has a low elastic modulus. While
The surface layer of the thermoplastic resin film has a high elastic modulus).

【0016】このような厚み方向に弾性率に差を有する
延伸フィルムを後述する収縮性フィルムによって収縮さ
せた場合、上記弾性率の差が原因となって、得られる複
屈折フィルムに厚み方向に均一な配向を付与することが
できず、Z配向係数が充分な数値を示さないことがあ
る。
When such a stretched film having a difference in elastic modulus in the thickness direction is shrunk by a shrinkable film described later, the resulting birefringent film has a uniform thickness in the thickness direction due to the difference in elasticity. In some cases, a proper orientation cannot be provided, and the Z orientation coefficient may not show a sufficient numerical value.

【0017】そこで、本発明では、収縮力を付与する前
の延伸フィルムの厚み方向における上記溶剤又は可塑剤
の全存在量の差を一定以下、詳しくは、収縮力を付与す
る前の延伸フィルムを厚み方向に略三等分割して得られ
る各ブロック間における溶剤又は可塑剤の全存在量、即
ち、可塑剤を含まない場合は溶剤の全存在量、可塑剤を
含む場合には溶剤と可塑剤との全存在量の差を0.30
重量%以下、好ましくは0.20重量%以下とし、延伸
フィルムの厚さ方向の弾性率を略均一化した上で、延伸
フィルムに所定方向の収縮力を付与している。
Therefore, in the present invention, the difference between the total amount of the solvent or the plasticizer in the thickness direction of the stretched film before the application of the shrinkage force is set to a certain value or less, more specifically, the stretched film before the application of the shrinkage force. The total amount of the solvent or plasticizer between the blocks obtained by dividing approximately three in the thickness direction, that is, the total amount of the solvent when no plasticizer is contained, and the solvent and the plasticizer when the plasticizer is contained. 0.30
% By weight, preferably 0.20% by weight or less, and after making the elastic modulus in the thickness direction of the stretched film substantially uniform, a contraction force in a predetermined direction is applied to the stretched film.

【0018】上記延伸フィルムを厚み方向に略三等分割
して得られる各ブロック間における溶剤又は可塑剤の全
存在量の差を0.30重量%以下とする方法としては、
特に限定されるものではないが、例えば、遠赤外線、マ
イクロ波等の電磁波を照射する方法等が挙げられる。
A method for reducing the difference in the total amount of the solvent or plasticizer between the blocks obtained by dividing the stretched film into approximately three equal parts in the thickness direction to 0.30% by weight or less is as follows.
Although not particularly limited, for example, a method of irradiating electromagnetic waves such as far infrared rays and microwaves may be used.

【0019】次に、上記の如く厚み方向の溶剤又は可塑
剤の全存在量の差を一定以下とした上記延伸フィルムの
片面又は両面に収縮性フィルムを貼着し、この収縮性フ
ィルムを上記延伸方向と直交する方向に収縮させ、上記
延伸フィルムに上記延伸方向と直交する方向に収縮力を
付与することによって複屈折フィルムを得る。
Next, a shrinkable film is adhered to one or both sides of the stretched film in which the difference in the total amount of the solvent or plasticizer in the thickness direction is not more than a certain value as described above, and this shrinkable film is stretched by the stretching method. The film is shrunk in a direction perpendicular to the direction, and a contraction force is applied to the stretched film in a direction perpendicular to the stretching direction to obtain a birefringent film.

【0020】上記収縮性フィルムとしては、所定温度範
囲において一定方向に収縮するものであれば、特に限定
されず、例えば、ポリカーボネート系樹脂、ポリエステ
ル系樹脂、ポリスチレン系樹脂、ポリエチレン系樹脂、
ポリプロピレン系樹脂、ポリ塩化ビニル系樹脂、ポリ塩
化ビニリデン系樹脂等からなる一軸延伸フィルムや二軸
延伸フィルム等が挙げられる。
The shrinkable film is not particularly limited as long as it shrinks in a predetermined direction within a predetermined temperature range. Examples of the shrinkable film include a polycarbonate resin, a polyester resin, a polystyrene resin, and a polyethylene resin.
Examples include a uniaxially stretched film and a biaxially stretched film made of a polypropylene resin, a polyvinyl chloride resin, a polyvinylidene chloride resin, and the like.

【0021】上記延伸フィルムの片面又は両面に上記収
縮性フィルムを貼着する方法は、汎用の手段が用いら
れ、延伸フィルムや収縮性フィルム自体の粘着力を利用
する方法や粘着剤等の剥離可能な接着手段を用いればよ
い。
The method of attaching the above-mentioned shrinkable film to one or both sides of the above-mentioned stretched film employs a general-purpose means, such as a method utilizing the adhesive force of the stretched film or the shrinkable film itself, and a method of peeling off an adhesive or the like. Any suitable bonding means may be used.

【0022】しかる後、片面又は両面に収縮性フィルム
が貼着された延伸フィルムを加熱して収縮性フィルムを
収縮させることによって、延伸フィルムに延伸方向と直
交する方向に作用する収縮力を付与して、これを収縮さ
せて、平面方向に配向した分子群と厚さ方向に配向した
分子群とが混在してなる複屈折フィルムを得ることがで
きる。
Thereafter, the stretched film having the shrinkable film adhered to one or both sides is heated to shrink the shrinkable film, thereby applying a shrink force acting on the stretched film in a direction perpendicular to the stretching direction. By shrinking this, a birefringent film in which a group of molecules oriented in a plane direction and a group of molecules oriented in a thickness direction are mixed can be obtained.

【0023】厚み方向に略三等分割して得られる各ブロ
ック間における溶剤又は可塑剤の全存在量の差を0.3
0重量%以下とした延伸フィルムは、その厚み方向に弾
性率が略均一化されており、延伸フィルムに付与される
収縮力を厚み方向に略均一に作用させることができる。
The difference in the total amount of the solvent or plasticizer between the blocks obtained by substantially equal division in the thickness direction is 0.3
The stretched film having 0% by weight or less has a substantially uniform elastic modulus in the thickness direction, and can apply the shrinkage force applied to the stretched film substantially uniformly in the thickness direction.

【0024】従って、得られる複屈折フィルムは、その
厚み方向の配向が均一で優れたZ配向係数を有し位相差
補償効果と視野角拡大効果に優れているとともに面内に
おける位相差値のばらつきが少ない。又、延伸フィルム
への収縮力付与も短時間且つ低温度で行うことができ
る。
Accordingly, the obtained birefringent film has a uniform orientation in the thickness direction, has an excellent Z-orientation coefficient, is excellent in phase difference compensation effect and viewing angle widening effect, and has a variation in in-plane retardation value. Less is. Also, the application of shrinkage force to the stretched film can be performed in a short time and at a low temperature.

【0025】[0025]

【実施例】(延伸フィルムの作製)ポリサルフォン樹脂
(帝人アモコエンジニアリングプラスチックス株式会社
製商品名「ユーデルP−3500」)100重量部とフ
タル酸ジブチル3重量部とをアニソールに濃度40重量
%となるように溶解させ、クロムメッキした平滑なスチ
ールベルト上にウエットの厚みが200μmとなるよう
に流延し、180℃で10分乾燥後巻取り、ポリサルフ
ォン樹脂フィルムを得た。そして、得られたポリサルフ
ォン樹脂フィルムをテンター延伸機にてその長さが1.
5倍となるように一軸延伸した。なお、得られた延伸フ
ィルムの厚みは60μmであった。そして、得られた延
伸フィルムに遠赤外線を照射しないものと遠赤外線を1
0分間又は20分間照射したものの双方を作製した。
EXAMPLES (Preparation of Stretched Film) 100 parts by weight of polysulfone resin (trade name "Udel P-3500" manufactured by Teijin Amoco Engineering Plastics Co., Ltd.) and 3 parts by weight of dibutyl phthalate in anisole at a concentration of 40% by weight. It was cast on a chrome-plated smooth steel belt so that the wet thickness was 200 μm, dried at 180 ° C. for 10 minutes, and wound up to obtain a polysulfone resin film. Then, the length of the obtained polysulfone resin film is set to 1.
The film was uniaxially stretched so as to be 5 times. In addition, the thickness of the obtained stretched film was 60 μm. Then, the obtained stretched film is not irradiated with far infrared rays,
Both were illuminated for 0 or 20 minutes.

【0026】上記遠赤外線照射しなかった延伸フィルム
と上記遠赤外線を照射した延伸フィルムの夫々の一部を
採取し厚み方向に三等分割し、これら夫々を塩化メチレ
ンに溶解し、ガスクロマトグラフィ(島津製作所製 G
C−14A)を用いて、それぞれに残留したアニソール
及びフタル酸ジブチルの量を測定し、残留アニソールと
残留フタル酸ジブチルの総量を表1に示した。
A portion of each of the stretched film not irradiated with the far infrared ray and the stretched film irradiated with the far infrared ray is sampled, divided into three equal parts in the thickness direction, and dissolved in methylene chloride. Manufacturing G
Using C-14A), the amounts of the remaining anisole and dibutyl phthalate were measured, and the total amount of the remaining anisole and dibutyl phthalate was shown in Table 1.

【0027】[0027]

【表1】 [Table 1]

【0028】(収縮性フィルムの作製)ポリカーボネー
ト樹脂(帝人化成株式会社製商品名「パンライトC−1
400)のペレットを準備し、これを塩化メチレンに溶
解後、流延法により製膜し、得られたフィルムをテンタ
ー延伸機によって一軸延伸し、150℃前後で一定方向
にのみ収縮する収縮性フィルムを得た。この収縮性フィ
ルムの一面にアクリル系粘着剤を30μmの厚さで層着
した。
(Preparation of shrinkable film) Polycarbonate resin (trade name "PANLITE C-1" manufactured by Teijin Chemicals Ltd.)
Prepare a pellet of 400), dissolve it in methylene chloride, form a film by a casting method, uniaxially stretch the obtained film by a tenter stretching machine, and shrink in only a certain direction at about 150 ° C. I got An acrylic pressure-sensitive adhesive was layered on one surface of the shrinkable film to a thickness of 30 μm.

【0029】(実施例1〜6)上記遠赤外線を照射した
延伸フィルムの一面に上記収縮性フィルムをその一面に
層着したアクリル系粘着剤を介して積層一体化して積層
体を得た。なお、延伸フィルムの一面に収縮性フィルム
を積層する際、延伸フィルムの延伸方向と収縮性フィル
ムの収縮方向とが互いに直交する方向となるようにし
た。
(Examples 1 to 6) The above-mentioned shrinkable film was laminated and integrated on one surface of the stretched film irradiated with far-infrared rays via an acrylic pressure-sensitive adhesive layered on one surface thereof to obtain a laminate. When laminating the shrinkable film on one side of the stretched film, the stretching direction of the stretched film and the shrinking direction of the shrinkable film were set to be orthogonal to each other.

【0030】次に、この積層体を表2に示した温度に保
持した炉内に表2に示した時間だけ滞留させて、収縮性
フィルムを一定方向に収縮させて、延伸フィルムにその
延伸方向と直交する方向に収縮力を付与し複屈折フィル
ムを得た。
Next, the laminate is kept in a furnace maintained at the temperature shown in Table 2 for the time shown in Table 2 so that the shrinkable film is shrunk in a certain direction. A birefringent film was obtained by applying a shrinking force in a direction perpendicular to the direction.

【0031】得られた複屈折フィルムのZ配向係数及び
面内における位相差値のばらつきを以下に示した方法で
測定しその結果を表2に示した。
The Z-orientation coefficient and the in-plane variation of the retardation value of the obtained birefringent film were measured by the following methods, and the results are shown in Table 2.

【0032】(Z配向係数の測定)得られた複屈折フィ
ルムのZ配向係数を自動複屈折計(王子計測機器株式会
社製商品名「KOBRA-21ADH 」)を用いて測定した。
(Measurement of Z-Orientation Coefficient) The Z-orientation coefficient of the obtained birefringent film was measured using an automatic birefringence meter (trade name “KOBRA-21ADH” manufactured by Oji Scientific Instruments).

【0033】(位相差値のばらつき)得られた複屈折フ
ィルムの任意の箇所を50cm四方に切取り、自動複屈
折計(王子計測機器株式会社製商品名「KOBRA-21ADH
」)を用いて面内の位相差値を測定し、最大値と最小
値の差を位相差値のばらつきとして測定した。
(Variation in retardation value) An arbitrary portion of the obtained birefringent film was cut into a square of 50 cm, and an automatic birefringence meter (trade name “KOBRA-21ADH” manufactured by Oji Scientific Instruments) was used.
)), The in-plane retardation value was measured, and the difference between the maximum value and the minimum value was measured as a variation in the retardation value.

【0034】[0034]

【表2】 [Table 2]

【0035】(比較例1〜5)上記遠赤外線を照射しな
かった延伸フィルムの一面に上記収縮性フィルムをその
一面に層着したアクリル系粘着剤を介して積層一体化し
て積層体を得た。なお、延伸フィルムの一面に収縮性フ
ィルムを積層する際、延伸フィルムの延伸方向と収縮性
フィルムの収縮方向とが互いに直交する方向となるよう
にした。
(Comparative Examples 1 to 5) A laminate was obtained by laminating and integrating the above-mentioned shrinkable film on one surface of the stretched film which was not irradiated with the far-infrared ray via an acrylic adhesive having one surface thereof layered. . When laminating the shrinkable film on one side of the stretched film, the stretching direction of the stretched film and the shrinking direction of the shrinkable film were set to be orthogonal to each other.

【0036】次に、この積層体を表3に示した温度に保
持した炉内に表3に示した時間だけ滞留させて、収縮性
フィルムを一定方向に収縮させて、延伸フィルムにその
延伸方向と直交する方向に収縮力を付与し複屈折フィル
ムを得た。
Next, the laminate is kept in a furnace maintained at the temperature shown in Table 3 for the time shown in Table 3 to cause the shrinkable film to shrink in a certain direction and to be stretched into a stretched film in the stretching direction. A birefringent film was obtained by applying a shrinking force in a direction perpendicular to the direction.

【0037】得られた複屈折フィルムのZ配向係数及び
面内における位相差値のばらつきを実施例1と同様の方
法で測定しその結果を表3に示した。
The Z-orientation coefficient and in-plane variation of the retardation value of the obtained birefringent film were measured in the same manner as in Example 1. The results are shown in Table 3.

【0038】[0038]

【表3】 [Table 3]

【0039】[0039]

【発明の効果】本発明の複屈折フィルムは、厚み方向に
略三等分割して得られる各ブロック間における溶剤又は
可塑剤の存在量の差が0.30重量%以下とした延伸フ
ィルムに収縮力を付与して得られたものであるので、フ
ィルムの厚み方向の配向が均一に分布しており、優れた
Z配向係数を有し、位相差値のばらつきが小さいととも
に優れた位相差補償効果と視野角拡大効果とを有する。
The birefringent film of the present invention shrinks to a stretched film in which the difference in the amount of the solvent or plasticizer between the blocks obtained by substantially equally dividing in the thickness direction is 0.30% by weight or less. Since it is obtained by applying a force, the orientation in the thickness direction of the film is uniformly distributed, has an excellent Z-orientation coefficient, has a small variation in retardation value, and has an excellent retardation compensation effect. And a viewing angle expanding effect.

Claims (1)

【特許請求の範囲】[Claims] 【請求項1】 熱可塑性樹脂と可塑剤との混合物又は熱
可塑性樹脂を溶剤に溶解後、この溶液を流延することに
よってフィルムを得、得られたフィルムを一軸延伸した
後、該延伸フィルムの片面又は両面に収縮性フィルムを
貼着し、この収縮性フィルムを上記延伸方向と直交する
方向に収縮させ、上記延伸フィルムに上記延伸方向と直
交する方向に収縮力を付与することによって得られる平
面方向に配向した分子群と厚さ方向に配向した分子群と
が混在してなる複屈折フィルムにおいて、上記延伸方向
と直交する方向に収縮力を付与する前の延伸フィルムを
厚み方向に略三等分割して得られる各ブロック間におけ
る溶剤又は可塑剤の全存在量の差が0.30重量%以下
であることを特徴とする複屈折フィルム。
A film is obtained by dissolving a mixture of a thermoplastic resin and a plasticizer or a thermoplastic resin in a solvent, casting the solution, and uniaxially stretching the obtained film. A plane obtained by attaching a shrinkable film to one or both sides, shrinking the shrinkable film in a direction perpendicular to the stretching direction, and applying a shrinking force to the stretched film in a direction orthogonal to the stretching direction. In a birefringent film in which a molecule group oriented in the direction and a molecule group oriented in the thickness direction are mixed, the stretched film before imparting a contraction force in a direction perpendicular to the stretching direction is substantially three or more in the thickness direction. A birefringent film, wherein the difference in the total amount of the solvent or plasticizer between the blocks obtained by division is 0.30% by weight or less.
JP10117112A 1998-04-27 1998-04-27 Birefringent film Pending JPH11305038A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP10117112A JPH11305038A (en) 1998-04-27 1998-04-27 Birefringent film

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP10117112A JPH11305038A (en) 1998-04-27 1998-04-27 Birefringent film

Publications (1)

Publication Number Publication Date
JPH11305038A true JPH11305038A (en) 1999-11-05

Family

ID=14703725

Family Applications (1)

Application Number Title Priority Date Filing Date
JP10117112A Pending JPH11305038A (en) 1998-04-27 1998-04-27 Birefringent film

Country Status (1)

Country Link
JP (1) JPH11305038A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9268076B2 (en) 2007-04-18 2016-02-23 Tosoh Corporation Optical compensation layer, optical compensation film, and processes for producing these

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9268076B2 (en) 2007-04-18 2016-02-23 Tosoh Corporation Optical compensation layer, optical compensation film, and processes for producing these

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