JP2573383B2 - Liquid crystal display - Google Patents
Liquid crystal displayInfo
- Publication number
- JP2573383B2 JP2573383B2 JP1115690A JP1115690A JP2573383B2 JP 2573383 B2 JP2573383 B2 JP 2573383B2 JP 1115690 A JP1115690 A JP 1115690A JP 1115690 A JP1115690 A JP 1115690A JP 2573383 B2 JP2573383 B2 JP 2573383B2
- Authority
- JP
- Japan
- Prior art keywords
- liquid crystal
- crystal display
- retardation
- degrees
- retardation plate
- 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.)
- Expired - Lifetime
Links
Landscapes
- Liquid Crystal (AREA)
Description
【発明の詳細な説明】 ＜産業上の利用分野＞ 本発明は位相差板が付与されたスーパーツイスト型の
液晶表示装置に関するものである。Description: TECHNICAL FIELD The present invention relates to a super twist type liquid crystal display device provided with a retardation plate.
＜従来の技術＞ 一般に、スーパーツイスト型液晶表示装置は、イエロ
ーグリーンあるいは、ブルーに着色するが、光学補償板
をもちいることにより、色補正を行い明るく鮮明な白／
黒表示が得られる。そのため、表示品位が向上し、ワー
プロ，コンピュータなどのOA機器の表示体として利用す
ることが出来る。<Conventional Technology> Generally, a super twist type liquid crystal display device is colored yellow green or blue, but by using an optical compensator, color correction is performed and bright and clear white /
A black display is obtained. Therefore, the display quality is improved, and it can be used as a display of OA equipment such as a word processor and a computer.
色補償を施したスーパーツイスト型液晶表示装置とし
ては、２層型のスーパーツイスト型液晶表示装置があ
り、１層目（駆動用パネル）で生じた着色を２層目（光
学補償用パネル）で色補正をし、無彩色化している。こ
の構造は、単層スーパーツイスト型液晶表示装置と比較
して液晶パネルが２枚必要である為、表示装置の厚みが
厚くなり重量が増加するという問題点をもっている。As a super twist type liquid crystal display device with color compensation, there is a two-layer type super twist type liquid crystal display device, in which coloring generated in the first layer (driving panel) is changed in the second layer (optical compensation panel). The color is corrected and achromatic. Since this structure requires two liquid crystal panels as compared with a single-layer super twist type liquid crystal display device, it has a problem that the thickness of the display device is increased and the weight is increased.
この問題点を解決するために光学補償板として一軸延
伸高分子フィルムからなる位相差板を用いることによ
り、薄型で軽量なスーパーツイスト型液晶表示装置（以
下単に位相差板方式STN液晶表示装置という）が開発さ
れた。ところが位相差板は、高分子フィルムを延伸して
作られるため、フィルムの延伸方向とこれに直交する方
向とでは、光学的性質が異なり、２層型のスーパーツイ
スト型液晶表示装置に比べ、位相差板方式STN液晶表示
装置は、方位角あるいは仰角による色変化が大きい、つ
まり、視角が狭いという問題点をもつている。In order to solve this problem, a thin and lightweight super twist type liquid crystal display device (hereinafter simply referred to as a phase difference plate type STN liquid crystal display device) is used by using a retardation plate made of a uniaxially stretched polymer film as an optical compensator. Was developed. However, since the retardation film is made by stretching a polymer film, the optical properties are different between the stretching direction of the film and the direction orthogonal thereto, and the retardation plate is different from the two-layer type super twist type liquid crystal display device. The phase difference plate type STN liquid crystal display device has a problem that a color change due to an azimuth angle or an elevation angle is large, that is, a viewing angle is narrow.
＜発明が解決しようとする課題＞ 一軸延伸高分子フィルムが位相差板として用いられる
のはその光学異方性による。即ち、高分子フィルムの延
伸方向とこれに直交する方向では、屈折率が異なる（複
屈折性）。この屈折率異方性△ｎとフィルムの厚みｄの
積で与えられるレターデーション（△ｎ・ｄ）は、フィ
ルムを通過するときに生じる光の位相差を与える物理量
であるが、この値の仰角による変化が延伸方向とこれに
直交する方向では異なっている。例えばポリカーボネイ
トからなる位相差板では、仰角が大きくなるに従い、延
伸方向でレターデーションは減少し、これに直交する方
向では増加する性質がある。この結果、液晶表示パネル
と組み合わせたとき、法線方向では光学補償関係が完全
であっても、仰角が大きくなるにつれて位相差板のレタ
ーデーションと液晶表示パネルのレターデーションの差
が大きくなり、光学補償関係がくずれる。つまり色変化
が生じ、表示のコントラストが低下する為視角が狭くな
る。<Problems to be solved by the invention> The uniaxially stretched polymer film is used as a retardation plate due to its optical anisotropy. That is, the refractive index differs between the stretching direction of the polymer film and the direction perpendicular thereto (birefringence). The retardation (Δn · d) given by the product of the refractive index anisotropy Δn and the thickness d of the film is a physical quantity that gives a phase difference of light generated when the light passes through the film. Is different between the stretching direction and the direction perpendicular thereto. For example, a retardation plate made of polycarbonate has a property that the retardation decreases in the stretching direction and increases in the direction perpendicular thereto as the elevation angle increases. As a result, when combined with a liquid crystal display panel, even if the optical compensation relationship is perfect in the normal direction, the difference between the retardation of the retarder and the retardation of the liquid crystal display panel increases as the elevation angle increases. The compensation relationship is broken. That is, a color change occurs and the contrast of display is reduced, so that the viewing angle is narrowed.
本発明はこのような問題点を解決するものであり、薄
型、軽量で鮮明な白／黒表示が得られ、かつ広視野角が
得られる液晶表示装置を提供することを目的とする。An object of the present invention is to solve such a problem, and an object of the present invention is to provide a liquid crystal display device which is thin, lightweight, can provide clear white / black display, and has a wide viewing angle.
＜課題を解決するための手段＞ 我々は、数々検討した結果、位相差板方式STN液晶表
示装置における視角を拡大するためには、次の２つの配
置構造が有効であることを見いだした。<Means for Solving the Problems> As a result of numerous studies, we have found that the following two arrangement structures are effective in increasing the viewing angle in a phase difference plate type STN liquid crystal display device.
第１の配置は２枚の位相差板をレターデーションが相
加される様に互いの遅相軸をずらして積層する構造であ
り、第２の配置は最大屈折率方向がその膜厚方向にある
高分子フィルムと位相差板を積層する構造である。The first arrangement is a structure in which two retardation plates are stacked with their slow axes shifted so that retardation is added, and the second arrangement has a maximum refractive index direction in the film thickness direction. This is a structure in which a certain polymer film and a retardation plate are laminated.
更に第１の配置構造を詳細に検討した結果、２枚の位
相差板の積層は互いの遅相軸の交差角が30度から40度を
なすように積層し、かつ液晶表示パネルに隣接する位相
差板の遅相軸と液晶表示パネルの隣接する基板のラビン
グ軸との交差角が70度から90度であるとき、視角拡大効
果が最も大きくなるという条件を見いだした。Furthermore, the first arrangement structure was examined in detail, and as a result, the two retardation plates were laminated so that the intersection angle of their slow axes was 30 to 40 degrees, and was adjacent to the liquid crystal display panel. It has been found that when the crossing angle between the slow axis of the phase difference plate and the rubbing axis of the adjacent substrate of the liquid crystal display panel is from 70 to 90 degrees, the condition for maximizing the viewing angle is maximized.
又第２の配置構造についても配設条件を検討した結
果、最大屈折率方向がその膜厚方向にある高分子フィル
ムはその延伸方向を位相差板の遅相軸に対して45度の交
差角をなすように積層し、かつ液晶表示パネルに隣接す
る位相差板の遅相軸と液晶表示パネルの隣接する基板の
ラビング軸との交差角が70度から90度であるとき、視角
拡大効果が最も大きくなるという条件を見いだした。以
下、この最大屈折率方向が膜厚方向にある高分子フィル
ムを視角補償板と呼ぶ。In addition, as a result of studying the disposition conditions for the second disposition structure, the polymer film having the maximum refractive index direction in the film thickness direction has its stretching direction set to an intersection angle of 45 degrees with the slow axis of the retardation plate. When the crossing angle between the slow axis of the phase difference plate adjacent to the liquid crystal display panel and the rubbing axis of the substrate adjacent to the liquid crystal display panel is 70 degrees to 90 degrees, the viewing angle expanding effect is increased. We found the condition of being the largest. Hereinafter, the polymer film having the maximum refractive index direction in the film thickness direction is referred to as a viewing angle compensator.
＜作 用＞ 一軸延伸高分子フィルムが位相差板として使用される
のは、その光学異方性のためである。即ち、延伸方向の
屈折率とこれに直交する方向の屈折率が異なる性質を利
用している。<Operation> The uniaxially stretched polymer film is used as the retardation plate because of its optical anisotropy. That is, the property that the refractive index in the stretching direction is different from the refractive index in the direction perpendicular to the stretching direction is used.
液晶表示パネルを通過した光（常光線と異常光線）の
相対位相差は位相差板を透過する時にその屈折率異方性
△ｎと膜厚ｄの積、つまりレターデーションによって打
ち消されるか、又は全波長が同位相に揃えられる事にな
る。しかし、これは表示装置を法線方向から見た場合で
あり、斜め方向から見た場合、即ち、視角特性を考える
場合位相差板の３次元的屈折率を考慮に入れなければな
らない。今、位相差板の３次元方向の屈折率をNMD（延
伸方向）,NTD（延伸方向と直交する方向）,NZD（厚み方
向）とすると、延伸方向とこれに直交する方向から見た
ときの屈折率異方性とレターデーションは、位相差板の
法線方向からの仰角をψとすると、次式で与えられる。The relative phase difference between the light (ordinary ray and extraordinary ray) that has passed through the liquid crystal display panel is canceled out by the product of the refractive index anisotropy Δn and the film thickness d, ie, the retardation, when the light passes through the phase difference plate, or All wavelengths will be aligned in phase. However, this is the case where the display device is viewed from the normal direction, and when viewed from an oblique direction, that is, when considering the viewing angle characteristics, the three-dimensional refractive index of the phase difference plate must be taken into consideration. Assuming that the three-dimensional refractive index of the retardation plate is N MD (stretching direction), N TD (direction perpendicular to the stretching direction), and N ZD (thickness direction), the retardation plate is viewed from the stretching direction and the direction perpendicular thereto. The refractive index anisotropy and the retardation are given by the following equation, where 、 is the elevation angle from the normal direction of the retardation plate.
（１）延伸方向から見たとき 屈折率異方性△NMD＝｛NMD 2NZD 2 ／（NMD 2sin2ψ＋NZD 2cos2ψ）｝1/2 −NTD 位相差RMD＝△NMD・d/cosψ （２）延伸方向と直交する方向から見たとき 屈折率異方性△NTD＝NMD−｛NTD 2NZD 2 ／（NTD 2sin2ψ＋NZD 2cos2ψ）｝1/2 位相差RTD＝△NTD・d/cosψ ３次元方向の屈折率をそれぞれ測定した上式に代入す
ると第３図が得られる。この結果より位相差板の延伸方
向ではレターデーションが減少し、延伸方向と直交する
方向ではレターデーションが増加する性質があることが
判る。(1) When viewed from the stretching direction Refractive index anisotropy △ N MD = ｛N MD 2 N ZD 2 / (N MD 2 sin 2 ψ + N ZD 2 cos 2 ψ)｝ 1/2 −N TD phase difference R MD = {N MD d / cos} (2) When viewed from the direction perpendicular to the stretching direction, refractive index anisotropy △ N TD = N MD − ｛N TD 2 N ZD 2 / (N TD 2 sin 2 ψ + N ZD 2) cos 2 ψ)｝ 1/2 phase difference R TD = △ N TD・ d / cosψ When the refractive indices in the three-dimensional directions are respectively substituted into the above equations, FIG. 3 is obtained. From this result, it can be seen that retardation decreases in the stretching direction of the retardation film and increases in the direction perpendicular to the stretching direction.
代表的な位相差板であるポリカーボネイトの場合につ
いて実際に仰角によるレターデーション変化をセナルモ
ンの方法を用いて測定した結果を第４図に示す。この結
果は上述の理論式より得られる傾向と一致している。第
４図より各仰角について方位角による変化を求めると第
５図が得られる。同様にして液晶表示パネルの方位角と
仰角によるレターデーション変化を求めた結果を第６図
に示す。FIG. 4 shows the results of actually measuring the retardation change due to the elevation angle using the method of Senarmont in the case of polycarbonate, which is a typical retardation plate. This result is consistent with the tendency obtained from the above theoretical formula. FIG. 5 is obtained by obtaining the change in azimuth angle for each elevation angle from FIG. FIG. 6 shows the result of similarly calculating the retardation change according to the azimuth and elevation of the liquid crystal display panel.
このような位相差板と液晶表示パネルを組み合わせた
表示装置を斜めから見たとき、両者のレターデーション
変化の傾向が異なるので光学補償関係はくずれ、光漏れ
や色変化が生じるので表示のコントラストが低下し、視
角が狭くなる。従って、視角を拡大するためには位相差
板の仰角によるレターデーション変化を小さくする必要
がある。When a display device combining such a retardation plate and a liquid crystal display panel is viewed obliquely, the tendency of the retardation change between the two is different, so the optical compensation relationship is broken, and light leakage and color change occur, resulting in a lower display contrast. And the viewing angle becomes narrower. Therefore, in order to increase the viewing angle, it is necessary to reduce the change in retardation due to the elevation angle of the phase difference plate.
第１の配置構造、即ち２枚の位相差板を積層する構造
では第５図に示されたように仰角に対するレターデーシ
ョン変化が最も小さい方位が延伸方向に対して30度から
40度ずれた方位に存在するので、一方の位相差板の遅相
軸（ポリカーボネイトの場合は延伸方向）をこの変化の
最も小さい方位に合わせるように積層すれば、仰角に対
するレターデーション変化を小さくすることが出来る。
これは２枚の位相差板を互いの遅相軸の交差角が30度か
ら40度で積層するということに他ならない。In the first arrangement structure, that is, the structure in which two retardation plates are stacked, the azimuth in which the change in retardation with respect to the elevation angle is the smallest from 30 degrees to the stretching direction as shown in FIG.
Since retardation exists in an orientation shifted by 40 degrees, the retardation change with respect to the elevation angle can be reduced by laminating the retardation axis of one of the retardation plates (the stretching direction in the case of polycarbonate) so as to match the orientation with the smallest change. I can do it.
This is nothing but the fact that two retardation plates are stacked at an intersection angle of the slow axis of each other of 30 to 40 degrees.
一方、第２の配置構造のおいて、視角補償板の仰角に
対するレターデーション変化を計算によって求めた結果
を第７図に示す。延伸方向とこれに直交する方向のレタ
ーデーション変化は位相差板とは逆に延伸方向で増加
し、これに直交する方向では減少する。この特徴を生か
し位相差板の仰角に対するレターデーション変化を相殺
するように視角補償板を配設すれば良い。この場合、延
伸による視角補償板の面内残余レターデーションがある
ので、その影響を最小限にするため位相差板の遅相軸と
の交差角を45度にする。これは最大屈折率方向が膜厚方
向にある高分子フィルム、即ち視角補償板の延伸方向と
位相差板の遅相軸との交差角を45度にして積層するとい
う事に他ならない。On the other hand, FIG. 7 shows a result obtained by calculating a change in retardation with respect to the elevation angle of the viewing angle compensating plate in the second arrangement structure. The retardation change in the stretching direction and the direction perpendicular to the stretching direction increases in the stretching direction contrary to the retardation plate, and decreases in the direction perpendicular to the retardation plate. A viewing angle compensating plate may be provided to take advantage of this feature so as to cancel the change in retardation with respect to the elevation angle of the phase difference plate. In this case, since there is residual retardation in the plane of the viewing angle compensating plate due to stretching, the crossing angle of the retardation plate with the slow axis is set to 45 degrees in order to minimize the influence. This is nothing more than laminating the polymer film having the maximum refractive index direction in the film thickness direction, that is, the crossing angle between the stretching direction of the viewing angle compensator and the slow axis of the retardation plate is 45 degrees.
ここで、これら２つの視角改良構造を位相差板方式ST
N液晶表示装置に適用する場合、まず基本となる位相差
板システムを決める必要がある。我々はシュミレーショ
ンによって高いコントラスト比が得られるシステムを求
めたところ、位相差板は１枚より２枚使用した方が良
く、２枚使用する場合はSTN液晶表示パネルの前面及び
背面にそれぞれ少なくとも１枚以上配設した方が良いと
いうことを見いだした。この基本システムにたいして２
つの視角改良構造を組み合わせる構成として次の５つが
提案できる。Here, these two viewing angle improving structures are referred to as phase difference plate type ST.
When applied to an N liquid crystal display device, it is first necessary to determine a basic retardation plate system. We found a system that can obtain a high contrast ratio by simulation. It is better to use two retarders than one, and when using two retarders, at least one retarder should be used on the front and back of the STN LCD panel. I found that it was better to arrange them. 2 for this basic system
The following five can be proposed as a configuration combining the two viewing angle improving structures.
液晶表示パネルの前面あるいは背面どちらか一方に第
１の配置構造を採用する。他方は位相差板１枚を配設す
る。The first arrangement structure is employed on either the front or the back of the liquid crystal display panel. The other is provided with one retardation plate.
液晶表示パネルの前面あるいは背面どちらか一方に第
２の配置構造を採用する。他方は位相差板１枚を配設す
る。The second arrangement structure is adopted on either the front surface or the back surface of the liquid crystal display panel. The other is provided with one retardation plate.
液晶表示パネルの前面及び背面に第１の配置構造を採
用する。The first arrangement structure is adopted on the front and back of the liquid crystal display panel.
液晶表示パネルの前面及び背面に第２の配置構造を採
用する。A second arrangement structure is employed on the front and back of the liquid crystal display panel.
液晶表示パネルの前面あるいは背面どちらか一方は第
１の配置構造を、他方は第２の配置構造を採用する。One of the front and rear surfaces of the liquid crystal display panel employs the first arrangement structure, and the other employs the second arrangement structure.
視角拡大効果としては第１の配置構造の方が大きいの
でこれら５つの構成を比較すると、＜＜＜＜
の順に広くなるが、の構成は位相差板を４枚使用する
のでON時の透過率が低下して位相差板方式STN液晶表示
装置の特徴である明るい表示が損なわれてしまう。従っ
て、高コントラスト比で明るい表示という従来の特徴を
生かしたまま視角拡大効果が得られのはの構成とな
る。すなわち、第１の配置構造と第２の配置構造を組み
合わせた本発明の構成のことである。Since the first arrangement structure has a larger viewing angle enlargement effect, when these five configurations are compared, <<<<<<
However, in this configuration, since four retardation plates are used, the transmittance at the time of ON is reduced, and a bright display characteristic of the STN liquid crystal display device of the retardation plate type is impaired. Therefore, the configuration which can obtain the viewing angle expanding effect while utilizing the conventional feature of bright display with a high contrast ratio is obtained. That is, the configuration of the present invention in which the first arrangement structure and the second arrangement structure are combined.
＜実施例＞ 以下第１図乃至第２図に従って本発明の一実施例を説
明する。<Embodiment> An embodiment of the present invention will be described below with reference to FIGS.
高分子材料でその主鎖方向に直交する方向に分極をも
つ材料、例えばPMMA（ポリメタクリル酸メチル）,EMMA
（エチレンメタクリル酸）,PS（ポリスチレン）は、延
伸によるフィルム形成でその厚み方向に最大屈折率方向
をもつ高分子フィルムとなる。これは本発明に使用され
る視角補償板となる。以下、ポリスチレンを使用した場
合の実施例について述べる。Polymer materials that have polarization in the direction perpendicular to the main chain direction, such as PMMA (polymethyl methacrylate), EMMA
(Ethylene methacrylic acid) and PS (polystyrene) form a polymer film having a maximum refractive index direction in the thickness direction by forming a film by stretching. This is the viewing angle compensator used in the present invention. Hereinafter, an example in which polystyrene is used will be described.
第１図は本発明の実施例による液晶表示装置の分解断
面図である。FIG. 1 is an exploded sectional view of a liquid crystal display according to an embodiment of the present invention.
1,2は偏光板で、単体透過率42％，偏光度99.99％のニ
ュートラルグレイタイプの偏光板を用い、3,4,5は一軸
延伸高分子フィルム（ポリカーボネイト）からなる厚み
50μの位相差板の各々のレターデーション値は200nm,20
0nm,400nmである。６はポリスチレンフィルムからなる
視角補償板で面内のレターデーション値は50nm、厚み方
向のレターデーション値は90nmである。7,8はガラス基
板であり、そのうえには透明電極ITO9,10が形成されて
いる。更にそのうえに11,12の有機配向膜が形成され、
液晶層13が240度捩れ構造をとるようにラビング配向処
理されている。Numerals 1 and 2 are polarizing plates, each using a neutral gray type polarizing plate with a single transmittance of 42% and a degree of polarization of 99.99%. Thicknesses of 3, 4 and 5 are made of uniaxially stretched polymer film (polycarbonate).
The retardation value of each of the 50μ retardation plates is 200 nm, 20
0 nm and 400 nm. Reference numeral 6 denotes a viewing angle compensator made of a polystyrene film. The in-plane retardation value is 50 nm, and the retardation value in the thickness direction is 90 nm. Reference numerals 7 and 8 denote glass substrates on which transparent electrodes ITO9 and ITO10 are formed. Furthermore, 11,12 organic alignment films are formed thereon,
The liquid crystal layer 13 is subjected to a rubbing alignment treatment so as to have a 240-degree twist structure.
液晶層13の液晶材料としては、正の誘電異方性を有す
るネマティック液晶、例えばフェニイルシクロヘキサン
（PCH）系液晶に捩れ方向を規制するためにカイラルド
ーパントとしてコレステリックノナネイト（CN）を1.45
wt％添加した混合液晶を用いる。混合液晶の屈折率異方
性△ｎは0.123であり、液晶層13の厚みは7.5μｍに設定
する。As a liquid crystal material of the liquid crystal layer 13, cholesteric nonaneate (CN) is used as a chiral dopant for controlling nematic liquid crystal having positive dielectric anisotropy, for example, phenylylcyclohexane (PCH) -based liquid crystal in order to control a twist direction.
A mixed liquid crystal with wt% added is used. The refractive index anisotropy Δn of the mixed liquid crystal is 0.123, and the thickness of the liquid crystal layer 13 is set to 7.5 μm.
第２図は本実施例の各部材の配設条件を示す図であ
る。P1は表側偏光板１の吸収軸方向で12時方向から３時
方向へ40度、P2は偏光板１に隣接する位相差板３の遅相
軸方向で12時方向から３時方向へ55度、P3はガラス基板
７に隣接する位相差板４の遅相軸方向で12時方向から３
時方向へ25度の角度をなす。この場合、積層された位相
差板3,4の遅相軸の交差角は30度になっている。P4,P5は
上側ガラス基板７、下側ガラス基板８の液晶分子配向軸
（ラビング軸）で時計方向に240度捩れた関係になって
いる。P6は下側ガラス基板８に隣接する位相差板５の遅
相軸方向で12時方向から９時方向へ25度、P7は視角補償
板６の延伸方向でP6とは45度の角度をなす。P8は下側偏
光板２の吸収軸方向で12時方向から９時方向へ75度の角
度になっている。FIG. 2 is a diagram showing conditions for disposing each member of the present embodiment. P1 is 40 degrees from the 12 o'clock direction to the 3 o'clock direction in the absorption axis direction of the front polarizing plate 1, and P2 is 55 degrees from the 12 o'clock direction to the 3 o'clock direction in the slow axis direction of the phase difference plate 3 adjacent to the polarizing plate 1. , P3 are 3 ° from the 12 o'clock direction in the slow axis direction of the retardation plate 4 adjacent to the glass substrate 7.
Make a 25 degree angle to the hour. In this case, the intersection angle of the slow axes of the laminated retardation plates 3 and 4 is 30 degrees. P4 and P5 are 240 degrees twisted clockwise in the liquid crystal molecule alignment axis (rubbing axis) of the upper glass substrate 7 and the lower glass substrate 8. P6 is a slow axis direction of the retardation plate 5 adjacent to the lower glass substrate 8 and is 25 degrees from 12:00 to 9 o'clock, and P7 is a direction of extension of the viewing angle compensator 6 and forms an angle of 45 degrees with P6. . P8 is at an angle of 75 degrees from the 12 o'clock direction to the 9 o'clock direction in the absorption axis direction of the lower polarizing plate 2.
第８図は本実施例と従来例の12時−６時方向を含む平
面で見た視角−コントラスト特性図である。ａの特性曲
線は本実施例、ｂの特性曲線は従来例を示している。白
黒表示が反転する、即ち、コントラスト比Coが1.0以下
になる視角範囲で比較した場合、従来例が52度なのに対
して本実施例では94度と約1.8倍に拡大する。ここで従
来例とはSTN液晶表示パネルの前面、背面に各々１枚の
位相差板を配設したものを言う。FIG. 8 is a view angle-contrast characteristic diagram of the present embodiment and the conventional example viewed on a plane including the 12: 00-6 o'clock direction. The characteristic curve a indicates the present embodiment, and the characteristic curve b indicates the conventional example. When the black-and-white display is inverted, that is, when compared in a viewing angle range where the contrast ratio Co is 1.0 or less, the conventional example is 52 degrees, whereas in the present embodiment, it is 94 degrees, which is about 1.8 times larger. Here, the conventional example refers to one in which one retardation plate is provided on each of the front and back surfaces of the STN liquid crystal display panel.
＜発明の効果＞ 以上本発明によれば、２枚の位相差板の積層構造と視
角補償板と位相差板の積層構造をSTN液晶表示パネルの
前面、背面に各々配設することによって、従来の位相差
板方式白黒液晶表示装置がもっていた仰角による色変
化、白黒表示の反転という現象による視角の狭さという
欠点を解消し、高コントラスト比で広視野角の白黒液晶
表示装置を実現出来、特に1024×768ドット、1120×800
ドット等の高精細で大型のディスプレイに適しており、
ワークステーション等への展開が可能となる。又、白黒
表示が安定していることからカラー表示においても視角
による表示色変化が最小となり、表示品位を著しく向上
させることが出来る。<Effects of the Invention> As described above, according to the present invention, the laminated structure of the two retardation plates and the laminated structure of the viewing angle compensating plate and the retardation plate are disposed on the front and back surfaces of the STN liquid crystal display panel, respectively. The disadvantage of the phase difference plate type black and white liquid crystal display device of having a narrow viewing angle due to the color change due to the elevation angle and the phenomenon of inversion of the black and white display can be resolved, and a black and white liquid crystal display device with a high contrast ratio and a wide viewing angle can be realized. Especially 1024 × 768 dots, 1120 × 800
Suitable for high-definition, large-sized displays such as dots,
It can be deployed to workstations and the like. Further, since the monochrome display is stable, the display color change due to the viewing angle is minimized even in the color display, and the display quality can be remarkably improved.
第１図は本発明による実施例の液晶表示装置の断面図、
第２図は本発明による実施例の各部材の配設条件を示す
図、第３図は位相差板の仰角によるレターデーション変
化を計算によって求めた図、第４図は実測した位相差板
の仰角によるレターデーション変化を示す図である。第
５図は位相差板の全方位に対するレターデーシヨンの変
化率を示す図、第６図はSTN液晶表示パネル（240度ツイ
スト）の全方位に対するレターデーシヨンの変化率を示
す図である。第７図は視角補償板の仰角に対するレター
デシヨン変化を計算によって求めた図である。第８図は
本発明の実施例と従来例の視角−コントラスト特性の比
較図である。 1,2……偏光板、3,4,5……位相差板（一軸延伸高分子フ
ィルム）、６……視角補償板、7,8……ガラス基板、9,1
0……透明電極、11,12……、13……液晶層。FIG. 1 is a sectional view of a liquid crystal display device according to an embodiment of the present invention,
FIG. 2 is a diagram showing the arrangement conditions of each member of the embodiment according to the present invention, FIG. 3 is a diagram obtained by calculating a change in retardation due to the elevation angle of the phase difference plate, and FIG. 4 is a diagram of the measured phase difference plate. FIG. 6 is a diagram illustrating a change in retardation due to an elevation angle. FIG. 5 is a diagram showing the change rate of the retardation in all directions of the retardation plate, and FIG. 6 is a diagram showing the change rate of the retardation in all directions of the STN liquid crystal display panel (240 ° twist). FIG. 7 is a diagram in which a change in the letter decision with respect to the elevation angle of the viewing angle compensator is obtained by calculation. FIG. 8 is a comparison diagram of viewing angle-contrast characteristics between the embodiment of the present invention and the conventional example. 1,2 ... Polarizing plate, 3,4,5 ... Retardation plate (uniaxially stretched polymer film), 6 ... Viewing angle compensator, 7,8 ... Glass substrate, 9,1
0: transparent electrode, 11, 12, ..., 13: liquid crystal layer.
Claims (2)
からなる位相差板をパネルの前面及び背面に配設したス
ーパーツイスト型の液晶表示装置において、前記光学補
償板のいずれか一方は２枚の位相差板の積層構造からな
り、他方は最大屈折率方向がその膜厚方向にある高分子
フィルムと位相差板の積層構造からなることを特徴とす
る液晶表示装置。1. A super twist type liquid crystal display device in which a retardation plate made of a uniaxially stretched polymer film is disposed on the front and back surfaces of a panel as an optical compensator, wherein one of the optical compensators is two sheets. A liquid crystal display device comprising a laminated structure of a retardation plate, and the other comprising a laminated structure of a polymer film and a retardation plate whose maximum refractive index direction is in the thickness direction thereof.
において、２枚の位相差板の積層は互いの遅相軸の交差
角が30度から40度をなし、かつ液晶表示パネルに隣接す
る位相差板の遅相軸と液晶表示パネルの隣接する基板の
ラビング軸との交差角が70度から90度であり、一方最大
屈折率方向が膜厚方向にある高分子フィルムと位相差板
の積層は、位相差板の遅相軸と高分子フィルムの延伸方
向が45度の交差角をなすように配設し、かつ液晶表示パ
ネルに隣接する位相差板の遅相軸と液晶表示パネルの隣
接する基板のラビング軸との交差角が70度から90度であ
ることを特徴とする液晶表示装置。2. A liquid crystal display device according to claim 1, wherein the two retardation plates have a crossing angle of 30 ° to 40 ° with respect to the slow axis of each other, and the liquid crystal display panel has The intersection angle between the slow axis of the adjacent retardation plate and the rubbing axis of the adjacent substrate of the liquid crystal display panel is 70 degrees to 90 degrees, while the phase difference between the polymer film and the maximum refractive index direction is in the film thickness direction. The lamination of the plates is arranged so that the slow axis of the retardation plate and the stretching direction of the polymer film make an intersection angle of 45 degrees, and the slow axis of the retardation plate adjacent to the liquid crystal display panel and the liquid crystal display A liquid crystal display device, wherein the crossing angle between the rubbing axis of the substrate adjacent to the panel is 70 degrees to 90 degrees.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1115690A JP2573383B2 (en) | 1990-01-19 | 1990-01-19 | Liquid crystal display |
| US07/564,769 US5126866A (en) | 1989-08-11 | 1990-08-09 | Liquid crystal display with a plurality of phase difference plates the slow axes of which form an angle of 20 to 40 degrees |
| KR1019900012297A KR940006983B1 (en) | 1989-08-11 | 1990-08-10 | Liquid crystal display device |
| EP90308844A EP0412844B1 (en) | 1989-08-11 | 1990-08-10 | Liquid crystal display |
| DE69025670T DE69025670T2 (en) | 1989-08-11 | 1990-08-10 | Liquid crystal display |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1115690A JP2573383B2 (en) | 1990-01-19 | 1990-01-19 | Liquid crystal display |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03215826A JPH03215826A (en) | 1991-09-20 |
| JP2573383B2 true JP2573383B2 (en) | 1997-01-22 |
Family
ID=11770165
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1115690A Expired - Lifetime JP2573383B2 (en) | 1989-08-11 | 1990-01-19 | Liquid crystal display |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2573383B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020050614A1 (en) * | 2018-09-04 | 2020-03-12 | 주식회사 엘지화학 | Device having variable transmittance |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04194820A (en) * | 1990-11-22 | 1992-07-14 | Sharp Corp | Liquid crystal display device |
| KR100294680B1 (en) * | 1993-06-07 | 2001-09-17 | 구본준, 론 위라하디락사 | Structure of film compensating type liquid crystal display |
| US5737047A (en) * | 1995-03-27 | 1998-04-07 | Casio Computer Co., Ltd. | Color liquid crystal display device with optical axes of retardation polarization plates set in an opposite direction of twist direction of LC molecules |
| JP3292809B2 (en) * | 1996-09-25 | 2002-06-17 | 松下電器産業株式会社 | Color liquid crystal display device |
| CN1161642C (en) * | 1997-05-09 | 2004-08-11 | 夏普公司 | Laminated phase plate and liquid crystal display comprising the plate |
| KR20040027216A (en) * | 2002-09-27 | 2004-04-01 | 삼성전자주식회사 | A OCB mode liquid crystal display and a driving method of the same |
-
1990
- 1990-01-19 JP JP1115690A patent/JP2573383B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020050614A1 (en) * | 2018-09-04 | 2020-03-12 | 주식회사 엘지화학 | Device having variable transmittance |
| US11391991B2 (en) | 2018-09-04 | 2022-07-19 | Lg Chem, Ltd. | Transmittance-variable device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03215826A (en) | 1991-09-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5249071A (en) | Liquid crystal display having positive and negative uniaxially oriented polymer films | |
| US5142393A (en) | Electro-optical liquid crystal device with compensator having negative optical anisotropy | |
| JPH02289824A (en) | Liquid crystal display element | |
| JPH09101515A (en) | Liquid crystal display device | |
| US5291323A (en) | Liquid crystal display device with positive and negative compensating films each with its optical axis parallel to the surface | |
| US8085370B2 (en) | Single-polarizer reflective bistable twisted nematic (BTN) liquid crystal display device | |
| EP0478383B1 (en) | Liquid crystal display apparatus | |
| JP2796210B2 (en) | Liquid crystal display | |
| JP2573383B2 (en) | Liquid crystal display | |
| KR20010072055A (en) | Improving the angle of view of a lcd screen by novel birefringent film stacking | |
| JP3712833B2 (en) | Reflective liquid crystal display | |
| Seiberle et al. | Multidomain LCDs and complex optical retarders generated by photo-alignment | |
| JP2892101B2 (en) | Full color liquid crystal display | |
| JP2695671B2 (en) | Liquid crystal display | |
| JP4553702B2 (en) | Liquid crystal display | |
| JP2659810B2 (en) | Liquid crystal display | |
| JPH06265875A (en) | Liquid crystal display device | |
| JPH01304422A (en) | Liquid crystal device | |
| JPH06230368A (en) | Phase difference plate and liquid crystal display device formed by using the same | |
| JP3031842B2 (en) | Liquid crystal display device | |
| JP3001767B2 (en) | Liquid crystal display | |
| JP2571631B2 (en) | Liquid crystal display | |
| JPH0519251A (en) | Liquid crystal display device | |
| JPH03269412A (en) | Liquid crystal display device | |
| JP2008020929A (en) | Liquid crystal display |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20071024 Year of fee payment: 11 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20081024 Year of fee payment: 12 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20081024 Year of fee payment: 12 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 13 Free format text: PAYMENT UNTIL: 20091024 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 13 Free format text: PAYMENT UNTIL: 20091024 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 14 Free format text: PAYMENT UNTIL: 20101024 |
|
| EXPY | Cancellation because of completion of term | ||
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101024 Year of fee payment: 14 |