JPH03241312A - Reflection type liquid crystal light valve - Google Patents
Reflection type liquid crystal light valveInfo
- Publication number
- JPH03241312A JPH03241312A JP2038766A JP3876690A JPH03241312A JP H03241312 A JPH03241312 A JP H03241312A JP 2038766 A JP2038766 A JP 2038766A JP 3876690 A JP3876690 A JP 3876690A JP H03241312 A JPH03241312 A JP H03241312A
- Authority
- JP
- Japan
- Prior art keywords
- light
- liquid crystal
- polarized light
- incident
- crystal layer
- 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
- 239000004973 liquid crystal related substance Substances 0.000 title claims abstract description 49
- 230000010287 polarization Effects 0.000 claims abstract description 19
- 239000000758 substrate Substances 0.000 claims description 4
- 239000011159 matrix material Substances 0.000 claims description 2
- 230000007423 decrease Effects 0.000 abstract description 7
- 230000003247 decreasing effect Effects 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 6
- 238000004458 analytical method Methods 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
Landscapes
- Liquid Crystal (AREA)
- Projection Apparatus (AREA)
- Devices For Indicating Variable Information By Combining Individual Elements (AREA)
- Transforming Electric Information Into Light Information (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明は、投写型表示装置等に使用する反射型液晶ライ
トバルブの偏光検光方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polarization analysis method for a reflective liquid crystal light valve used in a projection display device or the like.
［従来の技術］
従来の反射型液晶パネルを用いたライトパルプに於ける
偏光と検光の方法は、特開昭６３−２２８８８７号公報
の第１図に示されるような偏光ビームスプリッタ−を用
いる方法であった。[Prior Art] A conventional method of polarizing and analyzing light pulp using a reflective liquid crystal panel uses a polarizing beam splitter as shown in FIG. 1 of Japanese Patent Application Laid-Open No. 63-228887. It was a method.
［発明が解決しようとする課Ｈ］
しかしこの方法では、偏光ビームスプリッタ−の偏光度
に入射光の角度依存性があるために、入射光の平行性が
悪いと出射変調光のコントラストが著しく低下するとい
う問題点があり、またこのライトバルブを用いて投写型
カラー表示装置を構成した場合偏光ビームスプリッタ−
が３個必要になるので大型で高価なものになるという問
題点がある。そこで本発明はこの様な問題点を解決する
もので、その目的とするところは、コントラストの入射
光角度依存性が少なく小型で安価な反射型液晶ライトバ
ルブを提供することにある。[Problem H to be solved by the invention] However, in this method, since the degree of polarization of the polarizing beam splitter is dependent on the angle of the incident light, if the parallelism of the incident light is poor, the contrast of the output modulated light will be significantly reduced. There is also the problem that when a projection type color display device is constructed using this light valve, a polarizing beam splitter is required.
Since three are required, there is a problem that it becomes large and expensive. SUMMARY OF THE INVENTION The present invention is intended to solve these problems, and it is an object of the present invention to provide a small, inexpensive reflective liquid crystal light valve whose contrast is less dependent on the angle of incident light.
［課題を解決するための手段］
本発明の反射型液晶ライトバルブは、反射型液晶光変調
パネルと偏光検光器により構成され、前記反射型液晶光
変調パネルは、それぞれが独立に入射光を変調するマト
リックス状に配置された画素より成り、またそれぞれの
画素はおもに可視光を透過する電極を有する第１の共通
基板と可視光を反射する反射電極を有する第２の共通基
板とそれらにより挟持された液晶層とにより成り、また
前記偏光検光器が前記反射型光変調パネル側に配置され
たλ／４波長板と偏光板により構成され、入射光の変調
は前記両電極間の印加電圧によって前記液晶層のリタデ
ーションを変化させることで行なわれることを特徴とす
る。[Means for Solving the Problems] A reflective liquid crystal light valve of the present invention includes a reflective liquid crystal light modulation panel and a polarization analyzer, and each of the reflective liquid crystal light modulation panels independently receives incident light. It consists of pixels arranged in a matrix that modulates, and each pixel is sandwiched between a first common substrate having an electrode that mainly transmits visible light, and a second common substrate having a reflective electrode that reflects visible light. The polarization analyzer is composed of a λ/4 wavelength plate and a polarizing plate arranged on the side of the reflective light modulation panel, and the modulation of the incident light is performed by applying a voltage between the two electrodes. This is carried out by changing the retardation of the liquid crystal layer.
［作用］
本発明の上記構成によれば、偏光板とλ／４波長板によ
り構成される偏光検光器を通過した先は円偏光となり反
射型液晶パネルに入射する。この液晶パネルが捻れネマ
ティック方式の場合、電圧無印加では入射円偏光は液晶
層を通った後反射電極に於てほぼ直線偏光となって反射
され、再び液晶層を通って入射時と同じ回転方向の円偏
光に変換されるので、偏光検光器により直線偏光となっ
て出射する。液晶層に電圧を印加していくとあるしきい
値電圧から液晶層のリタデーションが減少し始めるので
、それに伴って出射光が徐々に減少しついには出射しな
くなる。このとき液晶パネルに入射する円偏光は、その
まま反射電極に到達して反射され逆回りの円偏光となっ
て偏光検光器に入射するので偏光板によってすべて吸収
される。[Function] According to the above configuration of the present invention, the light that passes through the polarization analyzer composed of the polarizing plate and the λ/4 wavelength plate becomes circularly polarized light and enters the reflective liquid crystal panel. When this liquid crystal panel is of the twisted nematic type, when no voltage is applied, the incident circularly polarized light passes through the liquid crystal layer and is reflected as almost linearly polarized light at the reflective electrode, and then passes through the liquid crystal layer again in the same rotational direction as when it was incident. Since the light is converted into circularly polarized light, it is emitted as linearly polarized light by a polarization analyzer. As a voltage is applied to the liquid crystal layer, the retardation of the liquid crystal layer starts to decrease from a certain threshold voltage, and accordingly, the emitted light gradually decreases and eventually ceases to be emitted. At this time, the circularly polarized light incident on the liquid crystal panel reaches the reflective electrode as it is, is reflected, becomes circularly polarized light in the opposite direction, and enters the polarization analyzer, where it is completely absorbed by the polarizing plate.
［実施例］
第１図は、本発明に於ける反射型液晶ライトバルブの構
成を示す構成図であり、偏光板１２の偏光軸とλ／４波
長板１３の光軸は、互いに４５゛の角度をなすように配
置されている。入射光１１は偏光板１２を通過して直線
偏光となった後λ／４波長板１３を通って円偏光となり
反射型液晶パネル１４に入射する。そしてこの反射型液
晶パネル１４が捻れネマティック方式の場合、電圧無印
加では入射円偏光は液晶層を通った後反射電極に於てほ
ぼ直線偏光となって反射され、再び液晶層を通って入射
時と同じ回転方向の円偏光に変換されるので、λ／４波
長板１３を通って入射時と同じ偏光面を持つ直線偏光と
なって偏光板１２を透過する。液晶層に電圧を印加して
いくとあるしきい値電圧から液晶層のリタデーションが
減少し始めるので、それに伴って偏光板１２を透過する
光の量が徐々に減少しついには透過しなくなる。このと
き液晶パネル１４に入射する円偏光は、そのまま反射電
極に到達して反射され逆回りの円偏光となってλ／４波
長板１３を通過し入射時と直交する直線偏光となるので
偏光板１２によってすべて吸収される。従って反射型液
晶パネル１４の各画素に対し画像情報を印加電圧の変化
として入力すると、その印加電圧に対応して変調されて
反射された光束はλ／４波長板１３と偏光板１２によっ
て検光されると画像情報を明暗として含むことになる。[Example] FIG. 1 is a block diagram showing the structure of a reflective liquid crystal light valve according to the present invention, and the polarization axis of the polarizing plate 12 and the optical axis of the λ/4 wavelength plate 13 are at an angle of 45 degrees They are arranged at an angle. The incident light 11 passes through a polarizing plate 12 to become linearly polarized light, and then passes through a λ/4 wavelength plate 13 to become circularly polarized light and enters a reflective liquid crystal panel 14 . When the reflective liquid crystal panel 14 is of a twisted nematic type, when no voltage is applied, the incident circularly polarized light passes through the liquid crystal layer and is reflected as almost linearly polarized light at the reflective electrode. Since the light is converted into circularly polarized light with the same rotational direction, it passes through the λ/4 wavelength plate 13 and becomes linearly polarized light having the same polarization plane as that at the time of incidence, and is transmitted through the polarizing plate 12. As a voltage is applied to the liquid crystal layer, the retardation of the liquid crystal layer starts to decrease from a certain threshold voltage, so that the amount of light that passes through the polarizing plate 12 gradually decreases and eventually stops passing through the polarizing plate 12. At this time, the circularly polarized light incident on the liquid crystal panel 14 reaches the reflective electrode as it is, is reflected, becomes circularly polarized light in the opposite direction, passes through the λ/4 wavelength plate 13, and becomes linearly polarized light orthogonal to the incident light, so the polarizing plate All are absorbed by 12. Therefore, when image information is input to each pixel of the reflective liquid crystal panel 14 as a change in applied voltage, the reflected light flux is modulated according to the applied voltage and is analyzed by the λ/4 wavelength plate 13 and the polarizing plate 12. In this case, image information will be included as brightness and darkness.
第２図は本発明による反射型液晶ライトバルブを用いた
モノクロームの投写型表示装置の構成を示す図であり、
偏光検光器２４は第１図における偏光板１２とλ／４波
長板１３により構成されている。光源装置２１から出射
した光束は、コリメートレンズ２３の焦点から僅かにず
れた位置に配置されたミラー２２に集光しコリメートレ
ンズ２３の方向に反射される。コリメートレンズ２３を
通過した光は平行光となり、偏光検光器２４と反射型液
晶パネル１４により構成されるライトバルブにより変調
と反射が行なわれた後、コリメートレンズ２３によって
ミラー２２から少しずれた位置に集光する。そして投写
レンズ２６を通ってスクリーン２７に結像する。なお、
偏光検光器２４は、その法線方向がレンズ２３の光軸と
僅かの角度を成すように配置されており、その表面反射
光はミラー２２に集光するので、表示画面のコントラス
ト比が偏光検光器２４の表面反射光によって低下すると
いうことはない。FIG. 2 is a diagram showing the configuration of a monochrome projection display device using a reflective liquid crystal light valve according to the present invention.
The polarization analyzer 24 is composed of the polarizing plate 12 and the λ/4 wavelength plate 13 shown in FIG. The light beam emitted from the light source device 21 is focused on a mirror 22 disposed at a position slightly shifted from the focal point of the collimating lens 23, and is reflected in the direction of the collimating lens 23. The light passing through the collimating lens 23 becomes parallel light, which is modulated and reflected by a light valve made up of a polarization analyzer 24 and a reflective liquid crystal panel 14, and is then moved to a position slightly shifted from the mirror 22 by the collimating lens 23. The light is focused on. Then, it passes through the projection lens 26 and forms an image on the screen 27 . In addition,
The polarization analyzer 24 is arranged so that its normal direction forms a slight angle with the optical axis of the lens 23, and the light reflected from its surface is focused on the mirror 22, so that the contrast ratio of the display screen is equal to that of the polarized light. It does not decrease due to the light reflected from the surface of the analyzer 24.
第３図は、カラー表示の場合の構成例を示す構成図であ
り、反射型液晶ライトバルブ３１Ｒ，３１Ｇ、３１Ｂは
本発明によるもので、第１図に示したように偏光板１２
．λ／４波長波長板１辰９場合はコリメートレンズ２３
によってほぼ平行にされた光束が、ダイクロイックプリ
ズム３２によって三原色に色分解される。モして各色に
対応する反射型液晶ライトバルブ３１Ｒ，３１Ｇ，３１
Ｂによって変調反射された光束は、ダイクロイックプリ
ズム３２によって色合成された後、コリメートレンズ２
３，投写レンズ２６を通ってスクリーン２７に結像する
。FIG. 3 is a configuration diagram showing an example of the configuration for color display, and the reflective liquid crystal light valves 31R, 31G, and 31B are according to the present invention, and the polarizing plate 12 is
．． If λ/4 wavelength plate 1 x 9, collimating lens 23
The luminous flux made almost parallel by the dichroic prism 32 is separated into three primary colors. Reflective liquid crystal light valves 31R, 31G, 31 corresponding to each color
The light beam modulated and reflected by B is color-combined by the dichroic prism 32, and then passes through the collimating lens 2.
3. The image is formed on the screen 27 through the projection lens 26.
［発明の効果］
以上述べたように本発明によれば反射型液晶ライトバル
ブの偏光検光手段として、偏光板とλ／４波長板を組み
合わせた薄型のものを用いるため、反射型液晶ライトバ
ルブが小型となり、また変調光が入射光と逆方向に出射
されるので、これを用いて投写型カラー表示装置を構成
すると光源光の色分解と色合成が一つのダイクロイック
プリズムによって行えるので、超小型の投写型カラー表
示装置を構成することができる。また偏光板を用いてい
るため、偏光度の入射角依存性が少なく、高いコントラ
スト比の表示が得られる。[Effects of the Invention] As described above, according to the present invention, a thin type combining a polarizing plate and a λ/4 wavelength plate is used as a polarization analysis means for a reflective liquid crystal light valve. is small, and the modulated light is emitted in the opposite direction to the incident light, so if this is used to configure a projection color display device, color separation and color synthesis of the light source light can be performed with a single dichroic prism, making it ultra-compact. A projection type color display device can be constructed. Furthermore, since a polarizing plate is used, the dependence of the degree of polarization on the incident angle is small, and a display with a high contrast ratio can be obtained.
第工図は本発明に於ける反射型液晶ライトバルブの構成
を示す構成図である。
第２図は本発明の反射型液晶ライトバルブを用いたモノ
クロームの投写型液晶表示装置の構成例を示す構成図で
ある。
第３図は本発明の反射型液晶ライトバルブを用いた投写
型カラー液晶表示装置の構成例を示す構成図である。
１２・・・偏光板
１３・・・λ／４波長板
１４・・−・−反射型液晶パネル
２１・・・光源装置
２３・・・コリメートレンズ
２６・・・投写レンズ
２ ７ ・
３ ２ ・
・スクリーン
・ダイクロイックプリズム
以 上
出願人 セイコーエプソン株式会社
代理人 弁理士 鈴木喜三部 化１名
第１図
第２図The fourth drawing is a configuration diagram showing the configuration of a reflective liquid crystal light valve in the present invention. FIG. 2 is a configuration diagram showing an example of the configuration of a monochrome projection type liquid crystal display device using the reflective type liquid crystal light valve of the present invention. FIG. 3 is a configuration diagram showing an example of the configuration of a projection type color liquid crystal display device using the reflective type liquid crystal light valve of the present invention. 12...Polarizing plate 13...λ/4 wavelength plate 14...-Reflective liquid crystal panel 21...Light source device 23...Collimating lens 26...Projection lens 27 3 2 . Screen dichroic prism and above Applicant Seiko Epson Co., Ltd. Agent Patent attorney Kizobe Suzuki 1 person Figure 1 Figure 2
Claims (2)
され、前記反射型液晶光変調パネルは、それぞれが独立
に入射光を変調するマトリックス状に配置された画素よ
り成り、またそれぞれの画素はおもに可視光を透過する
電極を有する第１の共通基板と可視光を反射する反射電
極を有する第２の共通基板とそれらにより挟持された液
晶層とにより成り、また前記偏光検光器が前記反射型光
変調パネル側に配置されたλ／４波長板と偏光板により
構成され、入射光の変調は前記両電極間の印加電圧によ
って前記液晶層のリタデーシヨンを変化させることで行
なわれることを特徴とする反射型液晶ライトバルブ。(1) Consisting of a reflective liquid crystal light modulation panel and a polarization analyzer, the reflective liquid crystal light modulation panel consists of pixels arranged in a matrix, each of which modulates incident light independently, and each pixel The polarization analyzer is mainly composed of a first common substrate having an electrode that transmits visible light, a second common substrate having a reflective electrode that reflects visible light, and a liquid crystal layer sandwiched therebetween; It is composed of a λ/4 wavelength plate and a polarizing plate arranged on the reflective light modulation panel side, and modulation of incident light is performed by changing the retardation of the liquid crystal layer by applying a voltage between the two electrodes. Reflective liquid crystal light valve.
射円偏光を前記反射電極に於てほぼ直線偏光に変換する
捻れネマティック方式の液晶パネルであることを特徴と
する請求項（１）記載の反射型液晶ライトバルブ。(2) The reflective liquid crystal light modulation panel is a twisted nematic type liquid crystal panel that converts incident circularly polarized light into substantially linearly polarized light at the reflective electrode when no voltage is applied. Reflective LCD light bulb.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2038766A JPH03241312A (en) | 1990-02-20 | 1990-02-20 | Reflection type liquid crystal light valve |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2038766A JPH03241312A (en) | 1990-02-20 | 1990-02-20 | Reflection type liquid crystal light valve |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03241312A true JPH03241312A (en) | 1991-10-28 |
Family
ID=12534412
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2038766A Pending JPH03241312A (en) | 1990-02-20 | 1990-02-20 | Reflection type liquid crystal light valve |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03241312A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5222395A (en) * | 1990-06-15 | 1993-06-29 | Oval Engineering Co., Ltd. | Thermal type flowmeter |
| KR100344880B1 (en) * | 1997-02-18 | 2003-01-15 | 다이니폰 인사츠 가부시키가이샤 | Polarization light splitting film, backlight system and liquid crystal display |
-
1990
- 1990-02-20 JP JP2038766A patent/JPH03241312A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5222395A (en) * | 1990-06-15 | 1993-06-29 | Oval Engineering Co., Ltd. | Thermal type flowmeter |
| KR100344880B1 (en) * | 1997-02-18 | 2003-01-15 | 다이니폰 인사츠 가부시키가이샤 | Polarization light splitting film, backlight system and liquid crystal display |
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