JPH0990357A - Liquid crystal display device - Google Patents
Liquid crystal display deviceInfo
- Publication number
- JPH0990357A JPH0990357A JP7241433A JP24143395A JPH0990357A JP H0990357 A JPH0990357 A JP H0990357A JP 7241433 A JP7241433 A JP 7241433A JP 24143395 A JP24143395 A JP 24143395A JP H0990357 A JPH0990357 A JP H0990357A
- Authority
- JP
- Japan
- Prior art keywords
- liquid crystal
- crystal display
- display device
- change rate
- refractive index
- 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
Links
Landscapes
- Liquid Crystal (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、液晶表示装置に関
する。[0001] The present invention relates to a liquid crystal display device.
【０００２】[0002]
【従来の技術】一般に、液晶表示素子は配向膜を形成し
た２枚の電極基板を支持体を介して配向層が対向する様
に重ね合わせ、周辺を接着剤により封着して液晶セルを
構成し、屈折率異方性△ｎの温度変化率が０．７５（％
／℃）且つ誘電率異方性△εの温度変化率が０．８５
（％／℃）の例えばシアノ−ＰＣＨ系液晶を封入した複
屈折モ−ド（ＳＴ）液晶表示素子の構造になっている。
また、前記液晶表示素子の背面に冷陰極管のバックライ
トを具備し、前記液晶表示素子の表面温度差を可及的に
少なくするように配置して液晶表示装置が形成されてい
た。2. Description of the Related Art Generally, in a liquid crystal display device, two electrode substrates each having an alignment film formed thereon are superposed on each other with a support between them so that the alignment layers face each other, and the periphery is sealed with an adhesive to form a liquid crystal cell. However, the temperature change rate of the refractive index anisotropy Δn is 0.75 (%
/ ° C) and the temperature change rate of the dielectric anisotropy Δε is 0.85.
(% / ° C.), for example, a cyano-PCH-based liquid crystal is enclosed in a birefringence mode (ST) liquid crystal display device.
Further, a liquid crystal display device is formed by providing a backlight of a cold cathode tube on the back surface of the liquid crystal display element and arranging it so as to minimize the surface temperature difference of the liquid crystal display element.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、液晶表
示装置では、バックライトの管表面の場所による発熱温
度差が３．５Ｗ型で１３℃もあり、この温度差がそのま
ま、液晶表示素子に伝わり表示面の温度差分布となり液
晶の屈折率異方性△ｎや誘電率異方性△εの温度変化が
著しく生じ、透過率むらや閾値電圧むらが生じ図３に示
すように、表示面１のバックライト２に近接する部分に
点灯時の表示むら３を生じさせ著しく表示品位を下げて
いた。特にカラ−表示液晶装置や白黒表示液晶装置にお
いては顕著であった。本発明はこれらを解決し、表示む
らを防止し、表示品位を向上させる液晶表示装置を得る
ものである。However, in the liquid crystal display device, the heat generation temperature difference due to the location of the surface of the tube of the backlight is 3.5 ° C. and 13 ° C., and this temperature difference is transmitted to the liquid crystal display element as it is and displayed. As a result of temperature difference distribution on the surface, the liquid crystal refractive index anisotropy Δn and the dielectric anisotropy Δε change remarkably with temperature, resulting in uneven transmittance and uneven threshold voltage, as shown in FIG. Display unevenness 3 at the time of lighting was caused in a portion close to the backlight 2 and the display quality was remarkably lowered. This was particularly noticeable in color display liquid crystal devices and monochrome display liquid crystal devices. The present invention provides a liquid crystal display device that solves these problems, prevents display unevenness, and improves display quality.
【０００４】[0004]
【課題を解決するための手段】本発明は、電極を有する
基板間に液晶を封入してなる複屈折制御効果形液晶表示
素子と、この液晶表示素子の背面に光を照射するために
前記液晶表示素子に近接配置したバックライトとを具備
した液晶表示装置において、前記バックライトにより加
熱される前記液晶表示素子の表示面に生じる表面温度差
を１℃以上１０℃未満に設定する手段と、前記液晶の屈
折率異方性△ｎの温度変化率を０．５０（％／℃）以下
且つ誘電率異方性△εの温度変化率が０．７５（％／
℃）以下に設定する手段とを具備したことを特徴とする
液晶表示装置を得るものである。The present invention is directed to a birefringence control effect type liquid crystal display device in which liquid crystal is sealed between substrates having electrodes, and the liquid crystal display device for irradiating light on the back surface of the liquid crystal display device. In a liquid crystal display device comprising a backlight arranged close to a display element, a means for setting a surface temperature difference generated on the display surface of the liquid crystal display element heated by the backlight to 1 ° C. or more and less than 10 ° C., The temperature change rate of the refractive index anisotropy Δn of the liquid crystal is 0.50 (% / ° C.) or less and the temperature change rate of the dielectric anisotropy Δε is 0.75 (% /
C)) and a means for setting the liquid crystal display device to below.
【０００５】液晶表示素子の使用温度２５℃〜５０℃で
のΔｎの温度変化率（％／℃）は、 （１−Δｎ（Ｔ＝50℃）／Δｎ（Ｔ＝25℃））×１０
０）／（５０−２５） で表し、図２（ａ）の破線領域範囲で表示品位が従来よ
り優れている。The temperature change rate (% / ° C.) of Δn at the operating temperature of the liquid crystal display device of 25 ° C. to 50 ° C. is (1-Δn (T = 50 ° C.) / Δn (T = 25 ° C.)) × 10
0) / (50-25), and the display quality is better than before in the range of the broken line area in FIG.
【０００６】また、Δｎの温度変化率（％／℃）は、 （１−Δε（Ｔ＝50℃）／Δε（Ｔ＝25℃））×１０
０）／（５０−２５） で表し、図２（ｂ）の破線の斜線領域範囲で表示品位が
従来より優れている。ここにＴは温度である。The temperature change rate of Δn (% / ° C.) is (1-Δε (T = 50 ° C.) / Δε (T = 25 ° C.)) × 10
0) / (50-25), and the display quality is superior to the conventional one in the range of the hatched area of the broken line in FIG. Where T is the temperature.
【０００７】これにより、バックライトからの発熱が前
記液晶表示素子に伝わっても前記液晶の屈折率異方性△
ｎや誘電率異方性△εの変化が少なく、透過率むらや閾
値電圧むらを少なくし点灯時の表示品位を上げた液晶表
示装置が得られる。As a result, even if the heat generated from the backlight is transmitted to the liquid crystal display element, the anisotropy of the refractive index of the liquid crystal Δ.
It is possible to obtain a liquid crystal display device in which the change in n and the dielectric anisotropy Δε is small, the transmittance unevenness and the threshold voltage unevenness are reduced, and the display quality at the time of lighting is improved.
【０００８】特にカラ−表示ＳＴ形ＬＣＤや白黒表示Ｓ
Ｔ形ＬＣＤでは表示むらが少なく著しく表示品位向上し
た液晶表示装置が得られた。Particularly, a color display ST type LCD and a black and white display S
With the T-type LCD, a liquid crystal display device having little display unevenness and significantly improved display quality was obtained.
【０００９】[0009]
【発明の実施の形態】以下、本発明の実施形態を参照し
て説明する。DETAILED DESCRIPTION OF THE INVENTION The embodiments of the present invention will be described below.
【００１０】図１において、例えばガラスからなる複数
個例えば２枚の基板１１、１２の一主面上にはそれぞ
れ、例えばＩＴＯ（インジウム・チン・オキサイド）か
らなる電極１３、１４が複数のストライプ形状で設けら
れ、基板の対向面で交差して例えば６４０×４００ドッ
トの画素を形成している。これらの基板１１、１２上の
電極１３、１４を覆うようにして例えばポリイミドから
なる配向膜１５、１６が形成され、これらの基板間に間
隙が生じるように例えばエポキシ樹脂からなる接着剤１
７によって保持する。In FIG. 1, a plurality of, for example, two substrates 11, 12 made of glass, for example, are provided with electrodes 13, 14 made of, for example, ITO (indium tin oxide) in a plurality of stripe shapes on one main surface. , And intersect with each other on the opposite surface of the substrate to form pixels of 640 × 400 dots, for example. Alignment films 15 and 16 made of, for example, polyimide are formed so as to cover the electrodes 13 and 14 on the substrates 11 and 12, and an adhesive 1 made of, for example, epoxy resin is formed so as to form a gap between these substrates.
Hold by 7.
【００１１】基板と接着剤によって液晶を注入するため
に一部に注入口を設け、液晶１９を入れる基板間隙を均
一にするために例えばジビニルベンゼン系からなる粒子
状の間隙支持体２０を設け、前記注入口１８より例えば
気圧差注入法によって例えば液晶の屈折率異方性△ｎの
温度変化率が０．４８（％／℃）で且つ誘電率異方性△
εの温度変化率が０．７３（％／℃）の例えばシアノＰ
ＣＨ系からなる液晶１９を封入する。An injection port is provided in a part for injecting liquid crystal with a substrate and an adhesive, and a particle-like gap support 20 made of, for example, divinylbenzene is provided in order to make the gap between the substrates into which the liquid crystal 19 is put uniform. From the injection port 18, for example, by the pressure difference injection method, the temperature change rate of the refractive index anisotropy Δn of the liquid crystal is 0.48 (% / ° C.) and the dielectric constant anisotropy Δ is obtained.
For example, cyano P having a temperature change rate of ε of 0.73 (% / ° C)
A liquid crystal 19 of CH type is enclosed.
【００１２】前記基板１１、１２を外面から挟むように
設置させた偏光板２１、２２とからなるＳＴＮ（スーパ
ーツイスト）の複屈折制御効果型液晶表示素子２３を形
成する。An STN (super twist) birefringence control effect type liquid crystal display element 23 is formed by polarizing plates 21 and 22 which are placed so as to sandwich the substrates 11 and 12 from the outside.
【００１３】さらに、液晶表示素子２３の背面外周に例
えば消費電力３Ｗ、直径３ｍｍの冷陰極管からなるバッ
クライト２４を近接配置して液晶表示装置２５を形成す
る。符号２６はバックライトの光を液晶表示素子に均一
に照射する光伝板を示す。Further, a liquid crystal display device 25 is formed by arranging a backlight 24, which is a cold cathode tube having a power consumption of 3 W and a diameter of 3 mm, close to the outer periphery of the back surface of the liquid crystal display element 23. Reference numeral 26 denotes a photoconductive plate that uniformly illuminates the liquid crystal display element with the light of the backlight.
【００１４】バックライト２４からの発熱の温度差が１
０℃で、この発熱による前記液晶表示素子２３の表面温
度差が５℃であった。このため、液晶１９に屈折率異方
性△ｎの温度変化率が０．４８（％／℃）で且つ誘電率
異方性△εの温度変化率が０．７３（％／℃）の材料を
用いたことと併せ、前記液晶表示装置２５は透過率むら
や閾値電圧むらが少なく著しく表示品位が向上した。The temperature difference of heat generated from the backlight 24 is 1
At 0 ° C., the surface temperature difference of the liquid crystal display element 23 due to this heat generation was 5 ° C. Therefore, the liquid crystal 19 has a refractive index anisotropy Δn with a temperature change rate of 0.48 (% / ° C.) and a dielectric constant anisotropy Δε with a temperature change rate of 0.73 (% / ° C.). In addition to the above, the liquid crystal display device 25 has little unevenness in transmittance and unevenness in threshold voltage, and the display quality is remarkably improved.
【００１５】なお、本発明は上記実施形態に限らず、液
晶表示素子の表示面に生じる表面温度差を１℃以上１０
℃未満に設定すること、さらに、図２に示すように
（ａ）の前記液晶の屈折率異方性△ｎの温度変化率を
０．５０（％／℃）以下且つ（ｂ）の誘電率異方性△ε
の温度変化率が０．７５（％／℃）以下に設定すること
により、表示品位の向上の効果を得ることができる。The present invention is not limited to the above-described embodiment, and the surface temperature difference occurring on the display surface of the liquid crystal display element is 1 ° C. or more and 10
The temperature change rate of the refractive index anisotropy Δn of the liquid crystal of (a) is 0.50 (% / ° C) or less and the dielectric constant of (b) is set to less than 0 ° C. Anisotropy △ ε
By setting the rate of temperature change of 0.75 (% / ° C.) or less, the effect of improving the display quality can be obtained.
【００１６】[0016]
【発明の効果】本発明は、バックライトからの発熱が液
晶表示素子に伝わって表示面の温度分布差を少なくし、
かつ液晶の屈折率異方性△ｎや誘電率異方性△εの温度
むらによる透過率むらや閾値電圧むらを少なくし、表示
品位を上げた液晶表示装置を得ることができる。According to the present invention, the heat generated from the backlight is transmitted to the liquid crystal display element to reduce the temperature distribution difference on the display surface.
In addition, it is possible to obtain a liquid crystal display device with improved display quality by reducing unevenness of transmittance and unevenness of threshold voltage due to temperature unevenness of refractive index anisotropy Δn and dielectric anisotropy Δε of liquid crystal.
【図１】本発明の実施形態の液晶表示装置の断面図であ
る。FIG. 1 is a sectional view of a liquid crystal display device according to an embodiment of the present invention.
【図２】本発明の実施形態の点灯表示品位を説明刷るも
ので、（ａ）は表示品位と、液晶の屈折率異方性△ｎの
温度変化率の関係を示す特性図、（ｂ）は表示品位と、
誘電率異方性△εの温度変化率の関係を示す特性図であ
る。2A and 2B are explanatory diagrams of a lighting display quality according to an embodiment of the present invention. FIG. 2A is a characteristic diagram showing a relationship between a display quality and a temperature change rate of a refractive index anisotropy Δn of a liquid crystal, and FIG. Is the display quality,
It is a characteristic view which shows the relationship of the temperature change rate of dielectric constant anisotropy (DELTA) (epsilon).
【図３】従来の液晶表示装置による温度むらの表示品位
を示した図である。FIG. 3 is a diagram showing display quality of temperature unevenness in a conventional liquid crystal display device.
１１、１２：基板 １３、１４：電極 １９： 液晶 ２３： 液晶表示素子 ２４ バックライト ２５ 液晶表示装置 11, 12: Substrate 13, 14: Electrode 19: Liquid crystal 23: Liquid crystal display element 24 Backlight 25 Liquid crystal display device
Claims (1)
る複屈折制御効果形液晶表示素子と、この液晶表示素子
の背面に光を照射するために前記液晶表示素子に近接配
置したバックライトとを具備した液晶表示装置におい
て、前記バックライトにより加熱される前記液晶表示素
子の表示面に生じる表面温度差を１℃以上１０℃未満に
設定する手段と、前記液晶の屈折率異方性△ｎの温度変
化率を０．５０（％／℃）以下且つ誘電率異方性△εの
温度変化率を０．７５（％／℃）以下に設定する手段と
を具備したことを特徴とする液晶表示装置。1. A birefringence control effect type liquid crystal display device, in which liquid crystal is sealed between substrates having electrodes, and a backlight arranged close to the liquid crystal display device for irradiating the back surface of the liquid crystal display device with light. And a means for setting the surface temperature difference generated on the display surface of the liquid crystal display element heated by the backlight to 1 ° C. or more and less than 10 ° C., and the refractive index anisotropy Δ of the liquid crystal. n is set to 0.50 (% / ° C.) or less and the dielectric anisotropy Δε is set to 0.75 (% / ° C.) or less. Liquid crystal display device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7241433A JPH0990357A (en) | 1995-09-20 | 1995-09-20 | Liquid crystal display device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7241433A JPH0990357A (en) | 1995-09-20 | 1995-09-20 | Liquid crystal display device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0990357A true JPH0990357A (en) | 1997-04-04 |
Family
ID=17074238
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7241433A Pending JPH0990357A (en) | 1995-09-20 | 1995-09-20 | Liquid crystal display device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0990357A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11237632A (en) * | 1998-02-24 | 1999-08-31 | Sharp Corp | Fluorescence type liquid crystal display device |
| US7268841B2 (en) * | 2002-07-04 | 2007-09-11 | Seiko Epson Corporation | Display device and electronic equipment having the same comprising a region for reflecting a polarized light and a region for absorbing the polarized light |
| US9030461B2 (en) | 2006-02-10 | 2015-05-12 | Koninklijke Philips N.V. | Large area thin film circuits employing current driven, illumination enhanced, devices |
-
1995
- 1995-09-20 JP JP7241433A patent/JPH0990357A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11237632A (en) * | 1998-02-24 | 1999-08-31 | Sharp Corp | Fluorescence type liquid crystal display device |
| US7268841B2 (en) * | 2002-07-04 | 2007-09-11 | Seiko Epson Corporation | Display device and electronic equipment having the same comprising a region for reflecting a polarized light and a region for absorbing the polarized light |
| US9030461B2 (en) | 2006-02-10 | 2015-05-12 | Koninklijke Philips N.V. | Large area thin film circuits employing current driven, illumination enhanced, devices |
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