JPH09160027A - Liquid crystal display device - Google Patents
Liquid crystal display deviceInfo
- Publication number
- JPH09160027A JPH09160027A JP7324625A JP32462595A JPH09160027A JP H09160027 A JPH09160027 A JP H09160027A JP 7324625 A JP7324625 A JP 7324625A JP 32462595 A JP32462595 A JP 32462595A JP H09160027 A JPH09160027 A JP H09160027A
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- Prior art keywords
- liquid crystal
- viewing angle
- angle
- crystal element
- scattering
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】この発明は液晶表示装置に関
するものである。[0001] The present invention relates to a liquid crystal display device.
【０００２】[0002]
【従来の技術】液晶表示装置としては、一般に、ＴＮ
（ツイステッドネマティック）型またはＳＴＮ（スーパ
ーツイステッドネマティック）型のものが利用されてい
る。これらの液晶表示装置は、液晶の分子を一対の基板
間においてツイスト配向させた液晶セルをはさんで表裏
一対の偏光板を配置してなる液晶素子と、この液晶素子
に光を照射する平面状光源とで構成されている。なお、
前記平面状光源としては、一般に、液晶素子の背後に配
置される、バックライトと呼ばれる光源が利用されてい
る。2. Description of the Related Art As a liquid crystal display device, TN is generally used.
(Twisted nematic) type or STN (super twisted nematic) type is used. These liquid crystal display devices include a liquid crystal element in which a pair of front and back polarizing plates are arranged with a liquid crystal cell in which liquid crystal molecules are twist-aligned between a pair of substrates, and a planar shape for irradiating the liquid crystal element with light. It is composed of a light source. In addition,
As the planar light source, a light source called a backlight, which is arranged behind a liquid crystal element, is generally used.
【０００３】ところで、上記ＴＮ型やＳＴＮ型の液晶表
示装置は、液晶素子の表示特性が表示の観察方向に応じ
て変化する。すなわち、この液晶表示装置は、表示特性
に液晶セルの液晶分子の配向状態によって決まる方向性
があり、そのため、視野角（表示を良好なコントラスト
で観察できる視角範囲）が狭いという問題をもってい
る。By the way, in the above-mentioned TN type or STN type liquid crystal display device, the display characteristics of the liquid crystal element change according to the viewing direction of the display. That is, this liquid crystal display device has a problem that the display characteristic has a directionality determined by the alignment state of the liquid crystal molecules of the liquid crystal cell, and therefore the viewing angle (the viewing angle range in which the display can be observed with good contrast) is narrow.
【０００４】これは、液晶セルのΔｎ・ｄ（液晶の屈折
率異方性Δｎと液晶層厚ｄとの積）の値が観察方向によ
って見かけ上変化するためであり、したがって、液晶セ
ルの両基板の内面にそれぞれ設けられている電極間への
印加電圧が同じであっても、つまり基板面に対する液晶
分子の立上がり角が同じであっても、光の透過率は観察
方向によって異なるから、上記液晶素子の電圧−透過率
特性には観察方向依存性がある。This is because the value of Δnd (the product of the refractive index anisotropy Δn of the liquid crystal and the thickness d of the liquid crystal layer) of the liquid crystal cell apparently changes depending on the viewing direction. Even if the applied voltage between the electrodes provided on the inner surface of the substrate is the same, that is, even if the rising angles of the liquid crystal molecules with respect to the substrate surface are the same, the light transmittance varies depending on the observation direction. The voltage-transmittance characteristic of the liquid crystal element depends on the viewing direction.
【０００５】この観察方向依存性は、前記電極間への印
加電圧が、液晶のしきい値電圧Ｖthと、液晶分子が基板
面に対してほぼ垂直に近い状態まで立上がり配向する電
圧Ｖa との間の値の電圧で、明るさに階調をもたせた階
調表示を行なわせるとき、中間調の表示の明るさが観察
方向によって大きく変化し、極端なコントラスト低下や
階調の反転を生じてしまう。The dependence on the viewing direction is that the voltage applied between the electrodes is between the threshold voltage Vth of the liquid crystal and the voltage Va at which the liquid crystal molecules rise and align to a state almost vertical to the substrate surface. When a gradation display is performed with a brightness value with a value of, the brightness of the halftone display changes significantly depending on the viewing direction, causing an extreme decrease in contrast and inversion of gradation. .
【０００６】そして、液晶素子には、コントラストが最
も高く観察される方向（以下、視角という）があり、液
晶素子の法線に対して視角がある方向から表示を観察し
たときは、ある程度の角度の範囲までは表示の明るさの
変化は比較的小さいが、前記法線に対して視角とは反対
の方向から表示を観察すると、極く狭い範囲の観察角の
変化によって表示の明るさが極端に変化して、コントラ
スト低下や階調反転を生じてしまう。The liquid crystal element has a direction in which the highest contrast is observed (hereinafter referred to as a viewing angle), and when the display is observed from a direction having a viewing angle with respect to the normal line of the liquid crystal element, a certain angle is observed. Although the change in the display brightness is relatively small up to the range, when the display is observed from the direction opposite to the viewing angle with respect to the normal line, the display brightness is extremely changed due to the change in the observation angle in an extremely narrow range. To cause a decrease in contrast and gradation inversion.
【０００７】なお、液晶素子は、一般に、その画面の法
線から画面の下縁方向に傾いた方向に視角の方向がくる
ように設計されたものが用いられており、このような液
晶素子を使用する液晶表示装置は、画面の法線から画面
の下縁方向への視野角（階調反転等が生じることなく良
好に見える観察方向の角度）はある程度広いが、画面の
上縁方向への視野角が極端に狭い。The liquid crystal element is generally designed so that the direction of the viewing angle is in the direction inclined from the normal of the screen to the lower edge direction of the screen, and such a liquid crystal element is used. The liquid crystal display device used has a wide viewing angle from the normal line of the screen to the lower edge direction of the screen (the angle of the viewing direction that can be viewed well without gradation inversion, etc.), but to the upper edge direction of the screen. The viewing angle is extremely narrow.
【０００８】そこで従来から、上記液晶表示装置の視野
角を改善する手段として、画素分割法が提案されてい
る。この画素分割法には、電圧制御方式と、配向制御方
式とがある。Therefore, conventionally, a pixel division method has been proposed as a means for improving the viewing angle of the liquid crystal display device. The pixel division method includes a voltage control method and an alignment control method.
【０００９】電圧制御方式は、液晶セルの一方の基板の
電極を各画素ごとに複数の電極に分割しておき、その各
分割電極と他方の基板の電極との間にそれぞれ異なる電
圧値の駆動電圧を印加することにより、液晶分子の立上
がり角を画素の各領域において異ならせて、これらの領
域の視野角（最も高いコントラストが得られる観察方
向）を異ならせたものであり、視野角が異なる複数の領
域が合成されて観察されるようにして、電圧−透過率特
性の観察方向依存性を小さくしたものである。In the voltage control method, an electrode on one substrate of a liquid crystal cell is divided into a plurality of electrodes for each pixel, and different voltage values are driven between each divided electrode and the electrode on the other substrate. By applying a voltage, the rising angle of the liquid crystal molecules is made different in each region of the pixel, and the viewing angle (observation direction in which the highest contrast is obtained) of these regions is made different. By making a plurality of regions synthesized and observed, the dependence of the voltage-transmittance characteristic on the observation direction is reduced.
【００１０】また、配向制御方式は、各画素をそれぞれ
複数の領域に区分して、その各領域ごとに液晶分子の配
向状態を異ならせることにより、これらの領域の視野角
を異ならせ、視野角が異なる複数の領域が合成されて観
察されるようにして、電圧−透過率特性の観察方向依存
性を小さくしたものである。In the alignment control system, each pixel is divided into a plurality of regions, and the alignment state of the liquid crystal molecules is made different in each region to make the viewing angles of these regions different and By observing a plurality of regions with different values, the dependence of the voltage-transmittance characteristic on the viewing direction is reduced.
【００１１】[0011]
【発明が解決しようとする課題】しかし、上記電圧制御
方式は、各分割電極にそれぞれ異なる電圧値の駆動信号
を供給しなければならないため、液晶表示装置の駆動制
御が複雑になってしまうという問題をもっている。However, in the above-described voltage control method, it is necessary to supply drive signals having different voltage values to each of the divided electrodes, so that the drive control of the liquid crystal display device becomes complicated. Have.
【００１２】一方、配向制御方式は、電圧制御方式のよ
うな複雑な駆動制御は不要であるが、液晶セルに、液晶
分子を画素の各領域ごとに異なる配向状態で配向させる
ための配向処理を施さなければならないため、液晶セル
の製造における配向処理が複雑になって、製造コストが
高くなるという問題をもっている。On the other hand, the alignment control method does not require complicated drive control such as a voltage control method, but the liquid crystal cell is provided with an alignment process for aligning liquid crystal molecules in different alignment states for each pixel region. Since it must be performed, there is a problem that the alignment process in the production of the liquid crystal cell is complicated and the production cost is increased.
【００１３】この発明は、複雑な駆動制御や複雑な配向
処理を行なうことなく、簡単な構成で広視野角化を実現
することができる液晶表示装置を提供することを目的と
したものである。SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display device which can realize a wide viewing angle with a simple configuration without performing complicated drive control and complicated alignment processing.
【００１４】[0014]
【課題を解決するための手段】この発明は、一対の基板
間にツイスト配向させた液晶が封入された液晶セルをは
さんで表裏一対の偏光板を配置してなる液晶素子と、前
記液晶素子に光を照射する平面状光源と、前記液晶素子
の出射側に配置された２枚の拡散板と、を備え、前記２
枚の拡散板はそれぞれ、拡散板の法線を含み、特定の方
向に沿った面に対して法線から所定の角度傾いた観察角
範囲において出射光の散乱の度合が観察角に応じて変化
する特性をもっており、かつ、一方の拡散板の散乱度合
が変化する観察角範囲が液晶素子の視角の方向に０°〜
４５°の間の所定の範囲に設定され、他方の拡散板の散
乱度合が変化する観察角範囲が前記視角とは反対の方向
に１０°〜３５°の間の所定の範囲に設定されているこ
とを特徴とするものである。The present invention is directed to a liquid crystal element having a pair of front and back polarizing plates arranged with a liquid crystal cell in which a twisted liquid crystal is sealed between a pair of substrates, and the liquid crystal element. A planar light source that irradiates light onto the light source; and two diffusion plates that are arranged on the exit side of the liquid crystal element.
Each of the diffusing plates includes the normal of the diffusing plate, and the degree of scattering of the emitted light changes according to the viewing angle in the viewing angle range inclined by a predetermined angle from the normal to the surface along the specific direction. The viewing angle range in which the scattering degree of one of the diffusion plates changes is 0 ° to the viewing angle direction of the liquid crystal element.
The viewing angle range is set to a predetermined range of 45 °, and the scattering degree of the other diffuser plate changes to a predetermined range of 10 ° to 35 ° in the direction opposite to the viewing angle. It is characterized by that.
【００１５】この発明において、前記一方の拡散板の散
乱度合が変化する観察角範囲は１５°〜４５°であるの
が望ましく、前記他方の拡散板の散乱度合が変化する観
察角範囲は５°〜３５°であるのが望ましい。In the present invention, the observation angle range in which the scattering degree of the one diffusion plate changes is preferably 15 ° to 45 °, and the observation angle range in which the scattering degree of the other diffusion plate changes is 5 °. It is desirable that the angle is ˜35 °.
【００１６】この発明によれば、液晶素子からの出射光
が、上記２枚の拡散板によって散乱され、表示をコント
ラスト低下や階調反転のない良好な状態で観察できる視
野角が、液晶素子の視角の方向にもその反対の方向にも
広くなる。According to the present invention, the light emitted from the liquid crystal element is scattered by the two diffusion plates, and the viewing angle at which the display can be observed in a good state without deterioration of contrast or gradation inversion is that of the liquid crystal element. It widens in the direction of the viewing angle and in the opposite direction.
【００１７】そして、この発明は、液晶素子の出射側に
２枚の拡散板を設けることによって視野角を広くしたも
のであるから、従来の電圧制御方式や配向制御方式のよ
うに複雑な駆動制御や複雑な配向処理を行なうことな
く、簡単な構成で広視野角化を実現することができる。Further, according to the present invention, since the viewing angle is widened by providing the two diffusion plates on the exit side of the liquid crystal element, the complicated drive control such as the conventional voltage control method and orientation control method is performed. It is possible to realize a wide viewing angle with a simple structure without performing complicated alignment processing.
【００１８】[0018]
【発明の実施の形態】以下、この発明の実施の形態を図
面を参照して説明する。図１はこの発明の一実施例を示
す液晶表示装置の側面図であり、この液晶表示装置は、
液晶素子１０と、この液晶素子に光を照射する平面状光
源として前記液晶素子１０の背後に配置されたバックラ
イト２０と、前記液晶素子１０の出射側に互いに重ねて
配置された２枚の拡散板３１，３２とからなっている。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of a liquid crystal display device showing an embodiment of the present invention.
The liquid crystal element 10, a backlight 20 arranged behind the liquid crystal element 10 as a planar light source for irradiating the liquid crystal element with light, and two diffusers arranged on the emission side of the liquid crystal element 10 so as to overlap each other. It is composed of plates 31 and 32.
【００１９】前記液晶素子１０は、液晶の分子を一対の
透明基板１２ａ，１２ｂ間においてツイスト配向させた
液晶セル１１をはさんで一対の偏光板１３，１４を配置
したものである。The liquid crystal element 10 has a pair of polarizing plates 13 and 14 sandwiching a liquid crystal cell 11 in which liquid crystal molecules are twist-aligned between a pair of transparent substrates 12a and 12b.
【００２０】なお、図示しないが、液晶セル１１の両基
板１２ａ，１２ｂの内面にはそれぞれ、透明な電極が形
成されるとともに、液晶分子を所定の方向に配向させる
ための配向膜が設けられており、前記配向膜は、両基板
１２ａ，１２ｂの近傍における液晶分子の配向方向によ
って決まる視角の方向が所望の方向になるように配向処
理されている。Although not shown, transparent electrodes are formed on the inner surfaces of both substrates 12a and 12b of the liquid crystal cell 11, and an alignment film for aligning liquid crystal molecules in a predetermined direction is provided. The alignment film is subjected to an alignment treatment so that the direction of the viewing angle determined by the alignment direction of the liquid crystal molecules in the vicinity of both substrates 12a and 12b is a desired direction.
【００２１】この液晶素子１０は、例えば、液晶セル１
１の液晶分子のツイスト角をほぼ９０°とし、一対の偏
光板１３，１４をその透過軸を互いにほぼ直交させるか
あるいはほぼ平行にして配置したＴＮ型のものであり、
この実施例では、画面に垂直で前記画面の横軸（図にお
いて紙面に垂直な方向）に沿った面Ｈに対してある程度
画面の下縁方向に傾いた方向に視角の方向がくるように
設計したものを用いている。The liquid crystal element 10 is, for example, a liquid crystal cell 1.
1 is a TN type in which the twist angle of the liquid crystal molecules is substantially 90 °, and a pair of polarizing plates 13 and 14 are arranged so that their transmission axes are substantially orthogonal to each other or substantially parallel to each other;
In this embodiment, the viewing angle is designed to be inclined to the lower edge of the screen to some extent with respect to the plane H that is perpendicular to the screen and along the horizontal axis of the screen (direction perpendicular to the paper surface in the figure). I am using what I did.
【００２２】すなわち、この液晶素子１０は、画面の横
軸に対して、液晶セル１１の入射側基板１２ａの近傍に
おける液晶分子の配向方向を出射側から見て右回りにほ
ぼ４５°の方向、出射側基板１２ａの近傍における液晶
分子の配向方向を出射側から見て左回りにほぼ４５°の
方向とし、液晶の分子を、入射側基板１２ａから出射側
基板１２ａに向かい出射側から見て右回りにほぼ９０°
のツイスト角でツイスト配向させるとともに、入射側お
よび出射側の偏光板１３，１４を、その透過軸が前記液
晶セル１１の入射側および出射側基板１２ａ，１２ｂの
近傍における液晶分子の配向方向に対してほぼ平行させ
るかまたはほぼ直交させて設けたものであり、この液晶
素子１０の視角の方向は、画面に垂直で前記横軸に沿っ
た面Ｈに対してある程度画面の下縁方向に傾いた方向に
ある。That is, in the liquid crystal element 10, with respect to the horizontal axis of the screen, the alignment direction of the liquid crystal molecules in the vicinity of the incident side substrate 12a of the liquid crystal cell 11 is a direction of about 45 ° clockwise when viewed from the emission side, The alignment direction of the liquid crystal molecules in the vicinity of the emission side substrate 12a is set to a direction of approximately 45 ° counterclockwise when viewed from the emission side, and the liquid crystal molecules are directed from the incidence side substrate 12a to the emission side substrate 12a and viewed from the emission side to the right. Around 90 °
In addition to the twist orientation at the twist angle of, the incident-side and exit-side polarizing plates 13 and 14 have their transmission axes with respect to the orientation directions of liquid crystal molecules in the vicinity of the incident-side and exit-side substrates 12a and 12b of the liquid crystal cell 11. Are provided substantially parallel to each other or substantially orthogonal to each other, and the direction of the viewing angle of the liquid crystal element 10 is inclined to the lower edge direction of the screen to some extent with respect to the plane H which is perpendicular to the screen and is along the horizontal axis. In the direction.
【００２３】また、上記バックライト２０は、液晶素子
１０の入射側偏光板１３の背後に、前記液晶素子１０の
表示領域全体に対向させて配置された導光板２１と、こ
の導光板２１の両側の端面にそれぞれ対向させて配置さ
れた光源ランプ２２と、前記導光板２１および光源ラン
プ２２の背後に設けられたリフレクタ２３とからなって
いる。The backlight 20 includes a light guide plate 21 arranged behind the incident side polarization plate 13 of the liquid crystal element 10 so as to face the entire display area of the liquid crystal element 10, and both sides of the light guide plate 21. And a reflector 23 provided behind the light guide plate 21 and the light source lamp 22, respectively.
【００２４】一方、上記２枚の拡散板３１、３２は、い
ずれも、拡散板の法線を含み、特定の方向に沿った面に
対して、法線から所定の角度傾いた観察角範囲において
出射光の散乱の度合が観察角に応じて変化する特性をも
った光学フィルムからなっている。On the other hand, each of the two diffuser plates 31 and 32 includes the normal line of the diffuser plate, and is in an observation angle range inclined by a predetermined angle from the normal line with respect to a plane along a specific direction. The optical film has a characteristic that the degree of scattering of emitted light changes depending on the observation angle.
【００２５】この光学フィルムは、光の散乱特性に入射
角依存性を有するものであり、特定の方向に沿いかつフ
ィルム面に対してある角度で交差する平面を光学的な基
準面とすると、この基準面に沿って入射する光はほとん
ど散乱させずに高い透過率で透過させ、前記平面に対し
てある角度範囲の入射角で入射する光は、その入射角が
大きくなるのにともなって大きな散乱率で拡散させる特
性をもっている。This optical film has an incident angle dependency on the light scattering property, and when a plane along a specific direction and intersecting the film surface at an angle is used as an optical reference plane, this Light incident along the reference plane is transmitted with a high transmittance with almost no scattering, and light incident at an incident angle within a certain angle range with respect to the plane is largely scattered as the incident angle increases. It has the property of diffusing at a rate.
【００２６】上記拡散板３１，３２に用いた光学フィル
ムは、上記基準面が、フィルム面に垂直で特定の方向に
沿った面に対してある程度傾いているものであり、この
拡散板３１，３２の入射角による散乱率の変化は、拡散
板面に垂直で特定の方向に沿った面を境にして、一方の
方向と反対の方向とで互いに異なっている。The optical films used for the diffusing plates 31 and 32 are such that the reference plane is inclined to some extent with respect to the plane perpendicular to the film surface and along a specific direction. The change in the scattering rate depending on the incident angle of is different between one direction and the opposite direction with the surface perpendicular to the diffusion plate surface and along a specific direction as a boundary.
【００２７】図２は、一方の拡散板３１の散乱特性を示
しており、この拡散板３１は、拡散板面に垂直で特定の
方向に沿った面ｈ1 の方向を観察角０°の方向とし、こ
の垂直面ｈ1 を境にして一方の方向（図において下方
向）からの出射光の観察角を＋の角度、他方の方向（図
において上方向）からの出射光の観察角を−の角度とし
たとき、０°〜＋４５°の間の所定の範囲において出射
光の散乱の度合が観察角に応じて変化する特性をもって
いる。FIG. 2 shows the scattering characteristic of one diffuser plate 31. In this diffuser plate 31, the direction of the plane h1 perpendicular to the diffuser plate surface and along a specific direction is the observation angle 0 °. , The viewing angle of the outgoing light from one direction (downward in the figure) is + angle, and the viewing angle of the outgoing light from the other direction (upward in the figure) is − angle with respect to the vertical plane h1. In this case, the degree of scattering of the emitted light changes in accordance with the observation angle in a predetermined range between 0 ° and + 45 °.
【００２８】この一方の拡散板３１の散乱度合が変化す
る観察角範囲ψ1 は、＋１５°〜＋４５°（図２におい
て斜線を施した範囲）に設定するのが望ましく、またそ
の観察角度範囲ψ1 の中でヘイズ率（拡散板面に対して
所定の角度の方向における透過光と散乱光との強度比）
が７０％〜９０％に変化するのが望ましい。The observation angle range ψ1 in which the scattering degree of the one diffusion plate 31 changes is preferably set to + 15 ° to + 45 ° (the hatched range in FIG. 2), and the observation angle range ψ1 Haze ratio (ratio of intensity of transmitted light and scattered light in the direction of a predetermined angle to the diffuser plate surface)
Is preferably 70% to 90%.
【００２９】このように、散乱度合が変化する観察角範
囲ψ1 （拡散領域）を＋１５°〜＋４５°に設定した拡
散板３１は、上記垂直面ｈ1 に対して＋１５°の方向の
範囲の観察角では出射角の散乱がほとんどなく、観察角
が＋１５°以上になると、観察角が大きくなるのにとも
なって散乱の度合が急激に大きくなり、観察角が＋４５
°を越えると、観察角が大きくなっても散乱の度合はほ
とんど変化しなくなる。As described above, the diffusion plate 31 in which the observation angle range ψ 1 (diffusion region) in which the scattering degree changes is set to + 15 ° to + 45 ° has the observation angle in the range of + 15 ° with respect to the vertical plane h1. When the observation angle is + 15 ° or more, there is almost no scattering of the exit angle, and the degree of scattering rapidly increases as the observation angle increases, and the observation angle becomes + 45 °.
When the angle exceeds °, even if the observation angle becomes large, the degree of scattering hardly changes.
【００３０】そして、上記一方の拡散板３１は、その拡
散領域を液晶素子１０の視野角の端にほぼ一致させて配
置する。この実施例では前記拡散板３１を、図１のよう
に、その特定の方向に沿った垂直面ｈ1 を、液晶素子１
０の横軸に沿った面、つまり、液晶素子１０の画面に垂
直でかつ視角方向を含む面と直交する面Ｈに一致させる
とともに、＋の観察角方向を液晶素子１０の視角の方向
に向けた状態で、前記液晶素子１０の出射側偏光板１４
の表面（出射面）に接着しており、これにより、拡散板
３１の拡散領域が液晶素子１０の視野角の端にほぼ一致
する。The one diffusion plate 31 is arranged such that its diffusion region substantially coincides with the end of the viewing angle of the liquid crystal element 10. In this embodiment, as shown in FIG. 1, the diffuser plate 31 has a vertical surface h1 along a specific direction thereof,
The plane along the horizontal axis of 0, that is, the plane H perpendicular to the screen of the liquid crystal element 10 and orthogonal to the plane including the viewing angle direction, is made coincident, and the + observation angle direction is directed to the viewing angle direction of the liquid crystal element 10. In this state, the exit side polarization plate 14 of the liquid crystal element 10 is
Is adhered to the surface (emission surface) of the liquid crystal panel, so that the diffusion region of the diffusion plate 31 substantially coincides with the end of the viewing angle of the liquid crystal element 10.
【００３１】また、図３は、他方の拡散板３２の散乱特
性を示しており、この拡散板３２は、拡散板面に垂直で
特定の方向に沿った面ｈ2 の方向を観察角０°の方向と
し、この垂直面ｈ2 を境にして一方の方向（図において
下方向）からの出射光の観察角を＋の角度、他方の方向
（図において上方向）からの出射光の観察角を−の角度
としたとき、＋１０°〜−３５°の間の所定の範囲にお
いて出射光の散乱の度合が観察角に応じて変化する特性
をもっている。FIG. 3 shows the scattering characteristics of the other diffusing plate 32. This diffusing plate 32 has a viewing angle of 0 ° in the direction of the plane h2 perpendicular to the diffusing plate surface and along a specific direction. Direction, the observation angle of the emitted light from one direction (downward in the figure) is +, and the observation angle of the emitted light from the other direction (upward in the figure) is-. The angle has a characteristic that the degree of scattering of the emitted light changes according to the observation angle in a predetermined range between + 10 ° and −35 °.
【００３２】この他方の拡散板３２の散乱度合が変化す
る観察角範囲ψ2 （拡散領域）は、−５°〜−３５°
（図３において斜線を施した範囲）に設定するのが望ま
しく、またその観察角度範囲ψ2 の中でヘイズ率が７０
％〜９０％に変化するのが望ましい。The observation angle range ψ 2 (diffusion region) in which the scattering degree of the other diffusion plate 32 changes is −5 ° to −35 °.
It is desirable to set it in the range (hatched in FIG. 3), and the haze ratio is 70 in the observation angle range ψ 2.
% To 90% is desirable.
【００３３】このように、散乱度合が変化する観察角範
囲ψ1 を−５°〜−３５°に設定した拡散板３１は、上
記垂直面ｈ2 に対して−５°の方向の範囲の観察角では
出射角の散乱がほとんどなく、−の角度方向の観察角が
−５°以上になると、観察角が大きくなるのにともなっ
て散乱の度合が急激に大きくなり、−の角度方向の観察
角が−３５°を越えると、観察角が大きくなっても散乱
の度合はほとんど変化しなくなる。As described above, the diffusion plate 31 in which the observation angle range ψ 1 in which the scattering degree changes is set to −5 ° to −35 ° has an observation angle in the range of −5 ° with respect to the vertical plane h2. When there is almost no scattering of the emission angle and the observation angle in the − angular direction becomes −5 ° or more, the degree of scattering rapidly increases as the observation angle increases, and the observation angle in the − angular direction becomes − If it exceeds 35 °, the degree of scattering hardly changes even if the observation angle becomes large.
【００３４】そして、上記他方の拡散板３２は、その拡
散領域を液晶素子１０の視野角の端にほぼ一致させて配
置する。この実施例では前記拡散板３１を、図１のよう
に、その特定の方向に沿った垂直面ｈ2 を、液晶素子１
０の画面に垂直でかつ視角方向を含む面と直交する面Ｈ
に一致させるとともに、−の観察角方向を前記液晶素子
１０の視角の方向とは反対の方向に向けた状態で、上記
一方の拡散板３１の表面に接着しており、これにより、
拡散板３２の拡散領域が液晶素子１０の視野角の端にほ
ぼ一致する。The other diffusion plate 32 is arranged so that its diffusion region substantially coincides with the end of the viewing angle of the liquid crystal element 10. In this embodiment, as shown in FIG. 1, the diffuser plate 31 has a vertical surface h2 along a specific direction thereof,
A plane H that is perpendicular to the screen of 0 and is orthogonal to the plane including the viewing angle direction
And is adhered to the surface of the one diffusing plate 31 in a state in which the viewing angle direction of − is directed in the direction opposite to the viewing angle direction of the liquid crystal element 10, and thereby,
The diffusion area of the diffusion plate 32 substantially coincides with the edge of the viewing angle of the liquid crystal element 10.
【００３５】この液晶表示装置は、バックライト２０か
ら液晶素子１０に照射されてこの液晶素子１０の表面側
に出射する光を、上述した２枚の拡散板３１，３２によ
って散乱させるようにしたものである。In this liquid crystal display device, light emitted from the backlight 20 to the liquid crystal element 10 and emitted to the surface side of the liquid crystal element 10 is scattered by the above-mentioned two diffusion plates 31 and 32. Is.
【００３６】この液晶表示装置においては、まず、一方
の拡散板３１の散乱度合が変化する観察角範囲を０°〜
＋４５°の間の所定の範囲（この実施例では＋１５°〜
＋４５°）に設定し、この一方の拡散板３１をその＋の
観察角方向を液晶素子１０の視角の方向に向けて設けて
いるため、液晶素子１０からの視角方向への出射光が前
記一方の拡散板３１によって散乱され、表示をコントラ
スト低下や階調反転のない良好な状態で観察できる視野
角が、液晶素子１０がもっている視野角よりも、さらに
視角方向に広くなる。In this liquid crystal display device, first, the observation angle range in which the degree of scattering of one diffusion plate 31 changes is 0 ° to.
A predetermined range between + 45 ° (+ 15 ° to + 15 ° in this embodiment)
(+ 45 °) and the one diffusion plate 31 is provided with its + viewing angle direction facing the viewing angle direction of the liquid crystal element 10, so that the light emitted from the liquid crystal element 10 in the viewing angle direction is The viewing angle that is scattered by the diffuser plate 31 and allows the display to be observed in a good state without a reduction in contrast and gradation inversion is wider than the viewing angle of the liquid crystal element 10 in the viewing angle direction.
【００３７】また、この液晶表示装置においては、他方
の拡散板３２の散乱度合が変化する観察角範囲を＋１０
°〜−３５°の間の所定の範囲（この実施例では−５°
〜−３５°）に設定し、この他方の拡散板３２をその−
の観察角方向を液晶素子１０の視角の方向とは反対の方
向に向けて設けているため、液晶素子１０からの視角方
向とは反対の方向への出射光が前記他方の拡散板３３に
よって散乱され、表示をコントラスト低下や階調反転の
ない良好な状態で観察できる視野角が、液晶素子１０が
もっている視野角に比べて、視角方向とは反対の方向に
も広くなる。Further, in this liquid crystal display device, the observation angle range in which the scattering degree of the other diffusion plate 32 changes is +10.
A predetermined range between ° and -35 ° (-5 ° in this example)
To -35 °), and the other diffusion plate 32 is set to-
Since the observation angle direction of is directed toward the direction opposite to the viewing angle direction of the liquid crystal element 10, the light emitted from the liquid crystal element 10 in the direction opposite to the viewing angle direction is scattered by the other diffusion plate 33. As a result, the viewing angle at which the display can be observed in a good state without deterioration in contrast or gradation inversion is wider in the direction opposite to the viewing angle direction than the viewing angle of the liquid crystal element 10.
【００３８】図１において、θは、上記液晶表示装置の
視野角を示しており、例えば、液晶素子１０の視野角θ
0 が、視角の方向に約４５°、視角方向とは反対の方向
に約１５°であり、一方の拡散板３１の散乱度合が変化
する観察角範囲が＋１５°〜＋４５°、他方の拡散板３
２の散乱度合が変化する観察角範囲が−５°〜−３５°
の場合、上記液晶表示装置の視野角θは、視角の方向に
５５°〜６５°、視角方向とは反対の方向に３５°〜４
５°である。In FIG. 1, θ indicates the viewing angle of the liquid crystal display device, for example, the viewing angle θ of the liquid crystal element 10.
0 is about 45 ° in the viewing angle direction and about 15 ° in the direction opposite to the viewing angle direction, and the observation angle range in which the scattering degree of one diffusion plate 31 changes is + 15 ° to + 45 ° and the other diffusion plate. Three
The observation angle range in which the scattering degree of 2 changes is −5 ° to −35 °
In this case, the viewing angle θ of the liquid crystal display device is 55 ° to 65 ° in the viewing angle direction and 35 ° to 4 ° in the direction opposite to the viewing angle direction.
5 °.
【００３９】すなわち、この液晶表示装置の視野角θ
は、液晶素子１０の視野角θ0 に比べて、視角の方向に
１０°〜２０°程度、視角方向とは反対の方向に２０°
〜３０°程度広くなっている。That is, the viewing angle θ of this liquid crystal display device
Is about 10 ° to 20 ° in the viewing angle direction and 20 ° in the direction opposite to the viewing angle direction as compared with the viewing angle θ 0 of the liquid crystal element 10.
It is about 30 ° wider.
【００４０】そして、上記液晶表示装置は、液晶素子１
０の出射側に２枚の拡散板３１，３２を設けることによ
って視野角を広くしたものであるから、従来の電圧制御
方式や配向制御方式のように複雑な駆動制御や複雑な配
向処理を行なうことなく、簡単な構成で広視野角化を実
現することができる。The liquid crystal display device has the liquid crystal element 1
Since the viewing angle is widened by providing the two diffusion plates 31 and 32 on the emission side of 0, complicated drive control and complicated alignment processing like the conventional voltage control method and orientation control method are performed. It is possible to realize a wide viewing angle with a simple configuration without any need.
【００４１】なお、上述したように、一方の拡散板３１
の散乱度合が変化する観察角範囲は＋１５°〜＋４５°
であるのが望ましく、また、他方の拡散板３２の散乱度
合が変化する観察角範囲は−５°〜−３５°であるのが
望ましいが、一方の拡散板３１の散乱度合が変化する観
察角範囲は＋１５°〜＋４５°の間の所定の範囲であ
り、他方の拡散板３２の散乱度合が変化する観察角範囲
が＋１０°〜−３５°の間の所定の範囲であれば、視野
角を、液晶素子１０の視角の方向とその反対の方向とに
広くすることができる。As described above, one diffusion plate 31
The observation angle range in which the degree of scattering changes is + 15 ° to + 45 °
It is desirable that the observation angle range in which the scattering degree of the other diffusion plate 32 changes is −5 ° to −35 °, but the observation angle in which the scattering degree of the one diffusion plate 31 changes. The range is a predetermined range between + 15 ° and + 45 °, and if the observation angle range in which the scattering degree of the other diffusion plate 32 changes is a predetermined range between + 10 ° and −35 °, the viewing angle is changed. , The viewing angle of the liquid crystal element 10 and the opposite direction can be widened.
【００４２】また、上記実施例では、２枚の拡散板３
１，３２を互いに重ねて、液晶素子１０の出射側偏光板
１４の表面に配置しているが、この拡散板３１，３２
は、その一方または両方を、前記出射側偏光板１４と液
晶セル１１との間に配置してもよい。In the above embodiment, the two diffusion plates 3 are used.
1, 32 are placed on the surface of the exit side polarization plate 14 of the liquid crystal element 10 so as to overlap each other.
One or both of them may be arranged between the emission side polarization plate 14 and the liquid crystal cell 11.
【００４３】さらに、上記実施例では、液晶素子１０に
光を照射する平面状光源として、光源ランプ２２からの
光を導光板２１により液晶素子１０に向けて照射する構
成のバックライト２０を用いたが、この平面状光源は、
例えばエリクトロルミネセンスパネル等でもよいし、ま
た平面状光源からの照射光は、ミラー等を備えた屈折光
路を経て液晶素子１０に入射させるようにしてもよい。Further, in the above-described embodiment, the backlight 20 having a structure in which the light from the light source lamp 22 is directed toward the liquid crystal element 10 by the light guide plate 21 is used as the planar light source for irradiating the liquid crystal element 10 with light. However, this planar light source
For example, an electroluminescence panel or the like may be used, or the irradiation light from the planar light source may be incident on the liquid crystal element 10 via a refracting optical path provided with a mirror or the like.
【００４４】[0044]
【発明の効果】この発明によれば、液晶素子からの出射
光が、上記２枚の拡散板によって散乱され、表示をコン
トラスト低下や階調反転のない良好な状態で観察できる
視野角が、液晶素子の視角の方向にもその反対の方向に
も広くなる。According to the present invention, the light emitted from the liquid crystal element is scattered by the above-mentioned two diffusion plates, and the viewing angle at which the display can be observed in a good state without deterioration in contrast or gradation inversion is It widens in the direction of the viewing angle of the element and in the opposite direction.
【００４５】そして、この発明は、液晶素子の出射側に
２枚の拡散板を設けることによって視野角を広くしたも
のであるから、従来の電圧制御方式や配向制御方式のよ
うに複雑な駆動制御や複雑な配向処理を行なうことな
く、簡単な構成で広視野角化を実現することができる。Further, according to the present invention, since the viewing angle is widened by providing the two diffusion plates on the exit side of the liquid crystal element, the complicated drive control such as the conventional voltage control method and orientation control method is performed. It is possible to realize a wide viewing angle with a simple structure without performing complicated alignment processing.
【図１】この発明の一実施例を示す液晶表示装置の側面
図。FIG. 1 is a side view of a liquid crystal display device showing an embodiment of the present invention.
【図２】一方の拡散板の散乱特性を示す図。FIG. 2 is a diagram showing a scattering characteristic of one diffusion plate.
【図３】他方の拡散板の散乱特性を示す図。FIG. 3 is a diagram showing a scattering characteristic of the other diffusion plate.
１０…液晶素子 １１…液晶セル １３，１４…偏光板 ２０…バックライト（平面状光源） ３１，３２…拡散板 ｈ1 ，ｈ2 …拡散板面に垂直で特定の方向に沿った面 Reference numeral 10 ... Liquid crystal element 11 ... Liquid crystal cell 13, 14 ... Polarizing plate 20 ... Backlight (planar light source) 31, 32 ... Diffusion plate h1, h2 ...
Claims (2)
封入された液晶セルをはさんで表裏一対の偏光板を配置
してなる液晶素子と、 前記液晶素子に光を照射する平面状光源と、 前記液晶素子の出射側に配置された２枚の拡散板と、を
備え、 前記２枚の拡散板はそれぞれ、拡散板の法線を含み、特
定の方向に沿った面に対して法線から所定の角度傾いた
観察角範囲において出射光の散乱の度合が観察角に応じ
て変化する特性をもっており、 かつ、一方の拡散板の散乱度合が変化する観察角範囲が
液晶素子の視角の方向に０°〜４５°の間の所定の範囲
に設定され、他方の拡散板の散乱度合が変化する観察角
範囲が前記視角とは反対の方向に１０°〜３５°の間の
所定の範囲に設定されていることを特徴とする液晶表示
装置。1. A liquid crystal element having a pair of front and back polarizing plates arranged with a liquid crystal cell in which twisted liquid crystal is sealed between a pair of substrates, and a planar light source for irradiating the liquid crystal element with light. And two diffuser plates arranged on the exit side of the liquid crystal element, each of the two diffuser plates including a normal line of the diffuser plate and normal to a plane along a specific direction. The degree of scattering of the emitted light changes according to the observation angle in the observation angle range inclined by a predetermined angle from the line, and the observation angle range in which the scattering degree of one diffusion plate changes is the viewing angle range of the liquid crystal element. Direction is set to a predetermined range between 0 ° and 45 °, and the viewing angle range in which the scattering degree of the other diffusion plate changes is a predetermined range between 10 ° and 35 ° in the direction opposite to the viewing angle. A liquid crystal display device characterized by being set to.
範囲は１５°〜４５°であり、他方の拡散板の散乱度合
が変化する観察角範囲は５°〜３５°であることを特徴
とする請求項１に記載の液晶表示装置。2. An observation angle range in which the scattering degree of one diffusion plate changes is 15 ° to 45 °, and an observation angle range in which the scattering degree of the other diffusion plate changes is 5 ° to 35 °. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is a liquid crystal display device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7324625A JPH09160027A (en) | 1995-12-13 | 1995-12-13 | Liquid crystal display device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7324625A JPH09160027A (en) | 1995-12-13 | 1995-12-13 | Liquid crystal display device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09160027A true JPH09160027A (en) | 1997-06-20 |
Family
ID=18167915
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7324625A Pending JPH09160027A (en) | 1995-12-13 | 1995-12-13 | Liquid crystal display device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09160027A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002099474A1 (en) * | 2001-06-01 | 2002-12-12 | Daicel Chemical Industries, Ltd. | Light diffusion film, surface illuminant device and liquid crystal display device |
| JP2005099484A (en) * | 2003-09-25 | 2005-04-14 | Toshiba Matsushita Display Technology Co Ltd | Liquid crystal display |
-
1995
- 1995-12-13 JP JP7324625A patent/JPH09160027A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002099474A1 (en) * | 2001-06-01 | 2002-12-12 | Daicel Chemical Industries, Ltd. | Light diffusion film, surface illuminant device and liquid crystal display device |
| US6917396B2 (en) | 2001-06-01 | 2005-07-12 | Daicel Chemical Industries, Ltd. | Light diffusion film, plane light source device and liquid crystal display apparatus for enhancing a constant luminance and diffusing a light |
| JP2005099484A (en) * | 2003-09-25 | 2005-04-14 | Toshiba Matsushita Display Technology Co Ltd | Liquid crystal display |
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