JPH0659235A - Projection type display device - Google Patents
Projection type display deviceInfo
- Publication number
- JPH0659235A JPH0659235A JP4211713A JP21171392A JPH0659235A JP H0659235 A JPH0659235 A JP H0659235A JP 4211713 A JP4211713 A JP 4211713A JP 21171392 A JP21171392 A JP 21171392A JP H0659235 A JPH0659235 A JP H0659235A
- Authority
- JP
- Japan
- Prior art keywords
- light
- polarizing
- display device
- light source
- projection type
- 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]
【産業上の利用分野】本発明は、光源から出射された光
線束が透過する偏光フィルタ、偏光板、偏光ビームスプ
リッタ等の偏光素子を備え、該光線束におけるS又はP
偏光成分を投影光として用いる投射光学系を有する投射
型表示装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a polarizing element such as a polarizing filter, a polarizing plate or a polarizing beam splitter through which a light beam emitted from a light source is transmitted.
The present invention relates to a projection type display device having a projection optical system that uses a polarization component as projection light.
【0002】[0002]
【従来の技術】かかる投射型表示装置には、例えば、光
導電型液晶ライトバルブ(LCLV素子)等を用いた液
晶表示装置がある。かかる光導電型液晶ライトバルブ
は、液晶層と光導電層との間に反射層等を設けた反射型
のものである。図1は、かかる反射型の投射型液晶表示
装置の構成の一例を示す。図において、光導電型液晶ラ
イトバルブ1の光導電層側は、CRT2のフロントフェ
イスに結合されている。CRTは、そのフロントフェイ
スに表示された像を光ファイバ層を介して導電型液晶ラ
イトバルブの光導電層に書き込む。光導電層の電位に応
じて液晶層の投影画像の濃淡が形成される。一方、メタ
ルハライドランプ等の光源3から発せられた光束は、コ
ールドミラー4、コンデンサレンズ5及び偏光板7等の
光学素子を経て、偏光ビームスプリッタ6に入射する。
この入射光のうちP偏光成分は、偏光ビームスプリッタ
6を通過する。S偏光成分は、偏光ビームスプリッタ6
で進行方向が曲げられて光導電型液晶ライトバルブ1に
入射する。2. Description of the Related Art An example of such a projection type display device is a liquid crystal display device using a photoconductive type liquid crystal light valve (LCLV element) or the like. Such a photoconductive liquid crystal light valve is of a reflective type in which a reflective layer or the like is provided between the liquid crystal layer and the photoconductive layer. FIG. 1 shows an example of the configuration of such a reflection type projection type liquid crystal display device. In the figure, the photoconductive layer side of the photoconductive liquid crystal light valve 1 is coupled to the front face of the CRT 2. The CRT writes the image displayed on its front face to the photoconductive layer of a conductive liquid crystal light valve through the optical fiber layer. The grayscale of the projected image of the liquid crystal layer is formed according to the potential of the photoconductive layer. On the other hand, the luminous flux emitted from the light source 3 such as a metal halide lamp is incident on the polarization beam splitter 6 via the cold mirror 4, the condenser lens 5, the optical elements such as the polarizing plate 7, and the like.
The P-polarized component of this incident light passes through the polarization beam splitter 6. The S-polarized component is the polarization beam splitter 6
Then, the traveling direction is bent and enters the photoconductive liquid crystal light valve 1.
【0003】ここで、光導電型液晶ライトバルブ1の液
晶層に投影画像が描かれていると、光導電型液晶ライト
バルブにおいて反射された反射光中には液晶層の像の濃
淡に応じて局部的にP偏光成分が含まれることになる。
そして、この反射光中のP偏光成分のみが偏光ビームス
プリッタ6をそのまま通過することにより、このP偏光
成分による像が投射レンズ8を介してスクリーン9上に
像が投射される。Here, when a projected image is drawn on the liquid crystal layer of the photoconductive liquid crystal light valve 1, the reflected light reflected by the photoconductive liquid crystal light valve 1 depends on the light and shade of the image of the liquid crystal layer. The P-polarized component will be locally included.
Then, only the P-polarized component in the reflected light passes through the polarization beam splitter 6 as it is, so that the image of the P-polarized component is projected on the screen 9 through the projection lens 8.
【0004】このように、これら投射型表示装置の筺体
中にメタルハライドランプ3等の高輝度な光源の下流
に、偏光ビームスプリッタ6、偏光板7等の光学素子が
配置されている。偏光ビームスプリッタの完全な偏光分
離は不可能であり、全波長用の偏光ビームスプリッタに
おいては最良でも2〜5%以上の漏れ光、即ち、偏光さ
れない余分な光が下流の光学系に達し、最終的には熱へ
変わる。偏光板7は、偏光度を上げる為に、偏光ビーム
スプリッタ6の上流に偏光板7を設け、熱対策から熱容
量の大きい偏光ビームスプリッタに貼り付けることが行
われる。As described above, the optical elements such as the polarization beam splitter 6 and the polarizing plate 7 are arranged downstream of the high-luminance light source such as the metal halide lamp 3 in the housing of these projection type display devices. Complete polarization separation of the polarization beam splitter is impossible, and in the polarization beam splitters for all wavelengths, at least 2 to 5% or more of leaked light, that is, unpolarized extra light reaches the downstream optical system, Changes to heat. In order to increase the degree of polarization, the polarizing plate 7 is provided with the polarizing plate 7 upstream of the polarizing beam splitter 6 and is attached to the polarizing beam splitter having a large heat capacity as a measure against heat.
【0005】[0005]
【発明が解決しようとする課題】しかし、偏光板や偏光
ビームスプリッタ等の光学素子は光吸収率が高く温度性
能限界があるので、高温度では使用できなくなる。さら
に、光導電型液晶ライトバルブを用いた投射型表示装置
では、その漏れ光は解像度及びコントラストの低下をも
招来する。However, since optical elements such as a polarizing plate and a polarizing beam splitter have a high light absorptivity and a temperature performance limit, they cannot be used at high temperatures. Further, in the projection type display device using the photoconductive type liquid crystal light valve, the leaked light causes deterioration of resolution and contrast.
【0006】本発明の目的は、光源から出射された光を
有効利用することができる投射型液晶表示装置を提供す
ることにある。It is an object of the present invention to provide a projection type liquid crystal display device which can effectively utilize the light emitted from the light source.
【0007】[0007]
【課題を解決するための手段】本発明の投射型表示装置
は、光源から出射された光線束が透過する偏光ビームス
プリッタを含む偏光素子を備え、該光線束におけるS又
はP偏光成分を投影光として用いる投射型表示装置であ
って、前記光線束の中心光軸上の前記光源と前記偏光素
子との間に配置され、前記中心光軸に対して対称に傾斜
し前記偏光素子に向けて凸形状となりかつ前記光線束が
入射角45度で入射する偏光板からなる偏光フィルタ
と、前記光源と前記偏光フィルタとの間に配置された位
相板と、を有することを特徴とする。A projection type display device of the present invention comprises a polarizing element including a polarizing beam splitter through which a light beam emitted from a light source passes, and an S or P polarization component in the light beam is projected onto a projection light. A projection type display device used as, arranged between the light source and the polarizing element on the central optical axis of the light flux, inclined symmetrically with respect to the central optical axis, and convex toward the polarizing element. It is characterized in that it has a polarizing filter formed of a polarizing plate having a shape and in which the light beam is incident at an incident angle of 45 degrees, and a phase plate arranged between the light source and the polarizing filter.
【0008】[0008]
【作用】本発明により、光源から出射された光を有効利
用することができるだけでなく、偏光ビームスプリッタ
への漏れ光を有効に除去し、偏光ビームスプリッタ或い
は偏光板等の光学素子の冷却を促進できる。According to the present invention, not only the light emitted from the light source can be effectively utilized, but also the leakage light to the polarization beam splitter can be effectively removed and the cooling of the optical element such as the polarization beam splitter or the polarizing plate can be promoted. it can.
【0009】[0009]
【実施例】図2は本発明による実施例の投射型表示装置
を示す。この投射表示装置は、光源3と該光源から出射
された光を受光する偏光ビームスプリッタ6の間、受光
面近傍に配置された偏光フィルタ20を有している。偏
光フィルタ20は、入射光束の中心光軸に対して対称で
かつ略45度傾斜した一対の偏光板であって偏光ビーム
スプリッタに向けて凸形状となった偏光板で20bを有
している。さらに、この投射表示装置は、光源3と偏光
フィルタ20との間に配置された位相板21を有してい
る。この表示装置における他の構成部材は図1の同一符
号に示すものと同一である。偏光ビームスプリッタ6の
更に受光面近傍に配置された偏光板7は、偏光度を上げ
るため設けられている。このように所望のP偏光成分を
投影光として用いるために偏光ビームスプリッタ6上流
において予め偏光度を上げるので偏光フィルタ20はプ
リポラライザともいう。FIG. 2 shows a projection type display device according to an embodiment of the present invention. This projection display device has a polarization filter 20 disposed between a light source 3 and a polarization beam splitter 6 that receives light emitted from the light source, and near the light receiving surface. The polarization filter 20 is a pair of polarizing plates that are symmetrical with respect to the central optical axis of the incident light beam and are inclined at about 45 degrees, and have a convex shape 20b toward the polarizing beam splitter. Further, this projection display device has a phase plate 21 arranged between the light source 3 and the polarization filter 20. Other components in this display device are the same as those shown in the same reference numerals in FIG. A polarizing plate 7 arranged further near the light receiving surface of the polarization beam splitter 6 is provided to increase the degree of polarization. Since the degree of polarization is increased upstream of the polarization beam splitter 6 in order to use the desired P-polarized component as the projection light in this way, the polarization filter 20 is also called a prepolarizer.
【0010】図3に示すように、かかる偏光フィルタ2
0の偏光板20bは、例えば入射光束の中心光軸を含む
平面に対して対称的な傾斜受光面を有する形状をしてい
る。これは、2枚の長方形の偏光板を、その各一辺縁部
にて当該平面内で接着することで形成できる。このよう
に、偏光板20bは、偏光ビームスプリッタ6の受光面
の光源側すなわち、光線の入射側に設置される。As shown in FIG. 3, such a polarization filter 2
The zero polarizing plate 20b has, for example, a shape having an inclined light receiving surface symmetrical with respect to a plane including the central optical axis of the incident light beam. This can be formed by adhering two rectangular polarizing plates in the plane at each one edge portion thereof. Thus, the polarizing plate 20b is installed on the light source side of the light receiving surface of the polarization beam splitter 6, that is, on the light incident side.
【0011】偏光板20bは、例えば図4に示すよう
に、ガラス平板10及びその両面に成膜された偏光膜1
1からなる。所定膜厚の偏光膜11には、屈折率が2.
25程度と高いTiO2,ZnS,ZrO2が用いられ
る。偏光膜11は各々同一膜厚dの一対の層であり、n
>ng(n=偏光膜11の屈折率,ng=ガラス平板1
0の屈折率)であり、かつn・d≒550/4nmであ
ることが好ましい。ガラス平板10の両面に偏光膜11
を成膜したのは、偏光度を上げるためである。The polarizing plate 20b is, for example, as shown in FIG. 4, a glass flat plate 10 and a polarizing film 1 formed on both surfaces thereof.
It consists of 1. The polarizing film 11 having a predetermined thickness has a refractive index of 2.
TiO 2 , ZnS, and ZrO 2 that are as high as 25 are used. The polarizing film 11 is a pair of layers each having the same film thickness d, and n
> Ng (n = refractive index of the polarizing film 11, ng = glass flat plate 1
(Refractive index of 0) and n · d≈550 / 4 nm. Polarizing films 11 on both sides of the glass plate 10
Was formed in order to increase the degree of polarization.
【0012】ここで、2枚の長方形の偏光膜のついたガ
ラス平板からなる偏光板20bの場合、投射型表示装置
において、図3に示す偏光板20bの図面の上方または
下方からへ空気を送るファン、空気経路等の送風手段を
配置すれば、偏光板20bを冷却できる。本実施例にお
いては、図5に示すように、偏光フィルタ20の偏光板
20bの形状は、光源3に向けて開放する即ち偏光ビー
ムスプリッタ6に向けて凸形状となり光軸に対して45
°傾斜した偏光板20bとする。本実施例においては、
メタルハライドランプ等の光源3とプリポラライザ20
との間に位相差を与える透明体即ち位相板21を設置す
る。この位相板21には例えば1/4波長板などがあ
る。また、位相板21としては光を施光させる液晶を用
いた液晶シャッターなどでも良い。本実施例において
は、1/4波長板21に直線偏光を角度θ=45°(直
線偏光の入射光線の電界ベクトルの振動方向と1/4波
長板の主断面とがなす角度)で入射させた場合、もし角
度θが−45°であるとすると、射出光線は逆回転の円
偏光となり、また伝搬の方向を逆にすると、すなわち円
偏光の光線を1/4波長板に入射させると、その射出光
線は直線偏光に変換される、ことを用いている。Here, in the case of the polarizing plate 20b made of a glass flat plate having two rectangular polarizing films, in the projection type display device, air is sent from above or below the drawing of the polarizing plate 20b shown in FIG. The polarizing plate 20b can be cooled by arranging a blowing means such as a fan or an air passage. In the present embodiment, as shown in FIG. 5, the polarizing plate 20b of the polarizing filter 20 has a shape that is open toward the light source 3, that is, convex toward the polarizing beam splitter 6, and is 45 with respect to the optical axis.
The polarizing plate 20b is inclined. In this embodiment,
Light source 3 such as metal halide lamp and pre-polarizer 20
A transparent body that gives a phase difference, that is, a phase plate 21 is installed. The phase plate 21 is, for example, a quarter wave plate. Further, the phase plate 21 may be a liquid crystal shutter using a liquid crystal that emits light. In this embodiment, linearly polarized light is made incident on the quarter-wave plate 21 at an angle θ = 45 ° (the angle formed by the vibration direction of the electric field vector of the incident light of linearly polarized light and the main cross section of the quarter-wave plate). In this case, if the angle θ is −45 °, the emitted light beam becomes circularly polarized light in the reverse rotation, and if the direction of propagation is reversed, that is, if the circularly polarized light beam is incident on the ¼ wavelength plate, The emitted light is converted into linearly polarized light.
【0013】したがって、図5において、メタルハライ
ドランプ光源3から出射した自然光は後方のリフレクタ
32によって、ほぼ平行光となり、下流へ向かう。その
後λ/4波長板21を通り、プリポラライザ20へ達す
る。プリポラライザ20では前述の作用により、偏光分
離され、光学系に対し、有効なP偏光は多く透過し、そ
のまま下流の光学系へ向かう。それに対し、不要なP偏
光成分は、図示の如くプリポラライザ20の偏光板20
bで2回反射され、再び光源方向に戻る。このP偏光成
分光は1/4波長板を通過することにより、π/2の位
相差を与えられ円又は楕円偏光となる。Therefore, in FIG. 5, the natural light emitted from the metal halide lamp light source 3 becomes substantially parallel light by the rear reflector 32 and travels downstream. After that, the light passes through the λ / 4 wave plate 21 and reaches the prepolarizer 20. In the prepolarizer 20, due to the above-mentioned action, the polarized light is separated, and a large amount of effective P-polarized light is transmitted to the optical system, and goes to the downstream optical system as it is. On the other hand, the unnecessary P-polarized component is the polarizing plate 20 of the prepolarizer 20 as shown in the figure.
It is reflected twice at b and returns to the light source again. The P-polarized component light passes through the quarter-wave plate and is given a phase difference of π / 2 to be circularly or elliptically polarized light.
【0014】この戻る光はリフレクタ32によってメタ
ルハライドランプ3の線光源へ集光されて戻り、メタル
ハライドランプ3の線光源近傍に設けられた反射膜33
で再び反射され、リフレクタ32から、また1/4波長
板21を通る。ここで再びπ/2の位相差が与えられ、
この光線は最初の振動方向を90°まげられる形とな
る。これにより、はじめはプリポラライザ20でカット
されたP偏光成分の光が有効となる。The returning light is condensed and returned by the reflector 32 to the linear light source of the metal halide lamp 3, and the reflecting film 33 provided near the linear light source of the metal halide lamp 3.
Is reflected again, and passes from the reflector 32 and again through the quarter-wave plate 21. Here, the phase difference of π / 2 is given again,
This ray has a shape in which the initial vibration direction can be bent by 90 °. As a result, the P-polarized light component cut by the prepolarizer 20 is initially effective.
【0015】このように、プリポラライザ20の偏光板
20bへの光線束の入射角が45°近傍になるように、
偏光板20bの形状は、光源3に向けて開放する中心光
軸に対して45°傾斜させることが望ましい。これによ
り偏光特性も良く、忠実にP偏光成分の光線がリフレク
タ32に戻る。実験の結果、偏光板20bの入射角を4
5°の他40°及び50°に変化させた場合でも、図6
に示すように、部分偏光における不要なS偏光の反射率
が約80%と高く、透過すべきP偏光の反射率が数%以
下との良好な結果を得た。このように、得られる部分偏
光におけるP偏光の反射率及びS偏光の反射率の差は大
きく、さらにS偏光を再度投影光として用いることがで
きる。In this way, the incident angle of the light beam on the polarizing plate 20b of the prepolarizer 20 is set to be near 45 °,
The shape of the polarizing plate 20b is preferably inclined by 45 ° with respect to the central optical axis opened toward the light source 3. As a result, the polarization characteristic is also good, and the ray of the P-polarized component returns to the reflector 32 faithfully. As a result of the experiment, the incident angle of the polarizing plate 20b was set to 4
Even when the angle is changed to 40 ° and 50 ° in addition to 5 °, FIG.
As shown in (1), the reflectance of the unnecessary S-polarized light in the partially polarized light was as high as about 80%, and the favorable reflectance of the P-polarized light to be transmitted was several% or less. As described above, the difference between the reflectance of P-polarized light and the reflectance of S-polarized light in the obtained partial polarized light is large, and the S-polarized light can be used again as the projection light.
【0016】プリポラライザ20において、偏光板20
bへの光線束の入射角を45°とする場合、偏光板20
bの周囲は屈折率の低い空気で満たすことなく、偏光板
20bを囲む透明筐体内に屈折率n=1.5程度の液体
20aを充填し偏光板20bの包囲することが好まし
い。偏光特性を向上させるためである。又、偏光板20
bを冷却できるためである。In the prepolarizer 20, the polarizing plate 20
When the incident angle of the light beam on b is 45 °, the polarizing plate 20
It is preferable that the surrounding of b is not filled with air having a low refractive index, and the liquid 20a having a refractive index of n = 1.5 is filled in the transparent casing surrounding the polarizing plate 20b to surround the polarizing plate 20b. This is to improve the polarization characteristics. Also, the polarizing plate 20
This is because b can be cooled.
【0017】図7は具体的に、RGB(赤緑青)発光の
3本のCRTを用いた投写型表示装置を示す。該装置
は、R、G及びGのCRT2、それぞれに対応するLC
LV素子1、全反射ミラーM、G反射ミラーMG、B反
射ミラーMB、液体偏光プリズム6、ズームレンズ8、
偏光板7、プリポラライザ20、位相差板21、IRカ
ットフィルタ31、リフレクタ32、メタルハライドラ
ンプ3を備えている。FIG. 7 specifically shows a projection type display device using three CRTs that emit RGB (red, green and blue) light. The apparatus includes R, G, and G CRTs 2 and LCs corresponding to the respective CRTs 2.
LV element 1, total reflection mirror M, G reflection mirror MG, B reflection mirror MB, liquid polarization prism 6, zoom lens 8,
A polarizing plate 7, a prepolarizer 20, a retardation plate 21, an IR cut filter 31, a reflector 32, and a metal halide lamp 3 are provided.
【0018】[0018]
【発明の効果】本発明によれば、光源から出射された光
線束が透過する偏光ビームスプリッタを含む偏光素子を
備え、該光線束におけるS又はP偏光成分を投影光とし
て用いる投射型表示装置において、光線束の中心光軸上
の光源と偏光素子との間に配置され、中心光軸に対して
対称に傾斜し偏光素子に向けて凸形状となりかつ光線束
が入射角45度で入射する偏光板からなる偏光フィルタ
と、光源と偏光フィルタとの間に配置された位相板と、
を有するので、光源から出射された光を有効利用するこ
とができるだけでなく、偏光素子の冷却をなすことがで
きる。According to the present invention, there is provided a projection type display device comprising a polarizing element including a polarizing beam splitter through which a light beam emitted from a light source is transmitted, and an S or P polarization component in the light beam is used as projection light. Polarized light which is arranged between the light source on the central optical axis of the light bundle and the polarizing element, is inclined symmetrically with respect to the central optical axis and has a convex shape toward the polarizing element, and the light bundle is incident at an incident angle of 45 degrees. A polarization filter made of a plate, a phase plate arranged between the light source and the polarization filter,
Therefore, not only the light emitted from the light source can be effectively used but also the polarizing element can be cooled.
【図1】反射型の投射型液晶表示装置の概略図である。FIG. 1 is a schematic view of a reflective projection type liquid crystal display device.
【図2】本実施例の反射型の投射型液晶表示装置の概略
図である。FIG. 2 is a schematic view of a reflective projection type liquid crystal display device of the present embodiment.
【図3】投射型表示装置における偏光ビームスプリッタ
及び入射光束の中心光軸に対して対称的に45度傾斜し
た偏光板を有する偏光フィルタの斜視図である。FIG. 3 is a perspective view of a polarization filter having a polarization beam splitter and a polarizing plate that is symmetrically inclined by 45 degrees with respect to a central optical axis of an incident light beam in a projection display device.
【図4】偏光板の拡大部分断面図である。FIG. 4 is an enlarged partial sectional view of a polarizing plate.
【図5】本実施例における偏光フィルタ及び該中心光軸
に対して傾斜受光面を有する偏光板への入射光束の様子
を示す概略図である。FIG. 5 is a schematic view showing a state of an incident light flux on a polarizing filter and a polarizing plate having a light receiving surface inclined with respect to the central optical axis in the present embodiment.
【図6】本発明による偏光フィルタの入射波長に対する
反射率の特性を示すグラフである。FIG. 6 is a graph showing characteristics of reflectance with respect to an incident wavelength of the polarization filter according to the present invention.
【図7】本実施例の投射型液晶表示装置の概略斜視図で
ある。FIG. 7 is a schematic perspective view of a projection type liquid crystal display device of this embodiment.
1 光導電型液晶ライトバルブ 2 CRT 3 メタルハライドランプ 4 コールドミラー 5 コンデンサレンズ 7 偏光板 6 偏光ビームスプリッタ 8 投射レンズ 9 スクリーン 20 偏光フィルタ 21 位相差板 1 Photoconductive Liquid Crystal Light Valve 2 CRT 3 Metal Halide Lamp 4 Cold Mirror 5 Condenser Lens 7 Polarizing Plate 6 Polarizing Beam Splitter 8 Projection Lens 9 Screen 20 Polarizing Filter 21 Phase Difference Plate
Claims (3)
光ビームスプリッタを含む偏光素子を備え、該光線束に
おけるS又はP偏光成分を投影光として用いる投射型表
示装置であって、 前記光線束の中心光軸上の前記光源と前記偏光素子との
間に配置され、前記中心光軸に対して対称に傾斜し前記
偏光素子に向けて凸形状となりかつ前記光線束が入射角
45度で入射する偏光板からなる偏光フィルタと、 前記光源と前記偏光フィルタとの間に配置された位相板
と、を有することを特徴とする投射型表示装置。1. A projection type display device comprising a polarizing element including a polarizing beam splitter through which a light beam emitted from a light source passes, wherein the S or P polarization component in the light beam is used as projection light. Is disposed between the light source and the polarizing element on the central optical axis of the optical element, is symmetrically inclined with respect to the central optical axis, has a convex shape toward the polarizing element, and the ray bundle is incident at an incident angle of 45 degrees. And a phase plate arranged between the light source and the polarizing filter.
を特徴とする請求項1記載の投射型表示装置。2. The projection type display device according to claim 1, wherein the periphery of the polarizing plate is filled with a liquid.
をそれぞれ成膜したことを特徴とする請求項1記載の投
射型表示装置。3. The projection type display device according to claim 1, wherein the polarizing plate is formed by forming polarizing films on both surfaces of a glass plate.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4211713A JPH0659235A (en) | 1992-08-07 | 1992-08-07 | Projection type display device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4211713A JPH0659235A (en) | 1992-08-07 | 1992-08-07 | Projection type display device |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0659235A true JPH0659235A (en) | 1994-03-04 |
Family
ID=16610371
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP4211713A Pending JPH0659235A (en) | 1992-08-07 | 1992-08-07 | Projection type display device |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0659235A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5934778A (en) * | 1998-03-10 | 1999-08-10 | Nec Corporation | Optical system for liquid crystal projector |
-
1992
- 1992-08-07 JP JP4211713A patent/JPH0659235A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5934778A (en) * | 1998-03-10 | 1999-08-10 | Nec Corporation | Optical system for liquid crystal projector |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7255444B2 (en) | Optical unit and projection-type image display apparatus using the same | |
US6340230B1 (en) | Method of using a retarder plate to improve contrast in a reflective imaging system | |
US5327270A (en) | Polarizing beam splitter apparatus and light valve image projection system | |
US6795243B1 (en) | Polarizing light pipe | |
US5453859A (en) | Polarization beam splitter and projection display apparatus | |
US7575325B2 (en) | Image displaying apparatus and color separating-combining optical system | |
JPH09281904A (en) | Improved projection system | |
JP4040484B2 (en) | Polarization separation optical system, projection display optical system, projection image display apparatus, and image display system | |
JPH07113709B2 (en) | Projection display device | |
JP2002031782A (en) | Projector | |
JPH06175123A (en) | Reflection type liquid crystal display device | |
JPH04184429A (en) | Polarizing light source and projection type liquid crystal display device using it | |
US7145719B2 (en) | Optical cores and projection systems containing the optical core | |
JP2009505141A (en) | Contrast enhancement for liquid crystal projection systems | |
JPH0572417A (en) | Polarized light converting element | |
JP3060720B2 (en) | Polarizing device and projection display device using the polarizing device | |
JP2003202558A (en) | Picture display device | |
US6123424A (en) | Optical system for use in an image projector | |
JPH0659235A (en) | Projection type display device | |
JPH05323117A (en) | Polarizing device and projection type display device using same | |
JP5625416B2 (en) | Liquid crystal device and projection display device | |
JP2828451B2 (en) | Liquid crystal projector, polarizer used for the same, and polarizing microscope using the polarizer | |
JPH05232433A (en) | Polarized light converting element and projection type liquid crystal display device | |
JPH0566368A (en) | Polarized light illumination device and projection display device using the same | |
US11754882B2 (en) | Optical compensation device and liquid crystal display device |