JPH04291333A - Projection display device - Google Patents
Projection display deviceInfo
- Publication number
- JPH04291333A JPH04291333A JP3057149A JP5714991A JPH04291333A JP H04291333 A JPH04291333 A JP H04291333A JP 3057149 A JP3057149 A JP 3057149A JP 5714991 A JP5714991 A JP 5714991A JP H04291333 A JPH04291333 A JP H04291333A
- Authority
- JP
- Japan
- Prior art keywords
- liquid crystal
- light
- crystal display
- display device
- projection
- 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.)
- Granted
Links
- 239000004973 liquid crystal related substance Substances 0.000 claims description 57
- 239000004983 Polymer Dispersed Liquid Crystal Substances 0.000 description 12
- 238000010586 diagram Methods 0.000 description 10
- 230000005684 electric field Effects 0.000 description 9
- 230000003287 optical effect Effects 0.000 description 6
- 229920000642 polymer Polymers 0.000 description 5
- 238000000149 argon plasma sintering Methods 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000005286 illumination Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 238000003786 synthesis reaction Methods 0.000 description 3
- 230000001788 irregular Effects 0.000 description 2
- 239000003086 colorant Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000994 depressogenic effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 230000009747 swallowing Effects 0.000 description 1
Landscapes
- Projection Apparatus (AREA)
Abstract
(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.
Description
【０００１】0001
【産業上の利用分野】本発明は光の透過と散乱により表
示を行なう液晶表示素子を用いた投写型液晶表示装置に
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type liquid crystal display device using a liquid crystal display element that performs display by transmitting and scattering light.
【０００２】0002
【従来の技術】従来、光の透過と散乱を用いた液晶表示
装置として、高分子分散型液晶（ＰＤＬＣ：Ｐｏｌｙｍ
ｅｒ−Ｄｉｓｐｅｒｓｅｄ Ｌｉｑｕｉｄ Ｃｒｙｓ
ｔａｌ）を用いた調光ガラスが実用化されている。これ
は図１に示すように高分子のスポンジ状三次元網目構造
の中に低分子液晶を保持した特殊な膜である。高分子分
散型液晶は、電圧印加にともなって光散乱状態から光透
過状態へと変化するので、この性質を利用して表示装置
としても用いられている。投写型液晶表示装置では光散
乱状態を黒とし光透過状態を白と表示するのが一般的で
あり、偏光板を必要としないので明るさを上げる手段と
して期待されている。[Prior Art] Conventionally, polymer dispersed liquid crystal (PDLC) has been used as a liquid crystal display device that uses light transmission and scattering.
er-Dispersed Liquid Crys
Light control glass using tal) has been put into practical use. As shown in Figure 1, this is a special film that holds low-molecular liquid crystals within a spongy three-dimensional polymer network structure. Polymer-dispersed liquid crystals change from a light-scattering state to a light-transmitting state as voltage is applied, and this property is used as a display device. Projection type liquid crystal display devices generally display black in a light scattering state and white in a light transmitting state, and because they do not require a polarizing plate, they are expected to be a means of increasing brightness.
【０００３】0003
【発明が解決しようとする課題】しかし前述の従来技術
を投写型液晶表示装置に用いた場合、白表示は偏光板を
使用しないため従来のＴＮモ−ドの投写型液晶表示装置
に比べ明るくできる反面、黒表示の散乱光を投写レンズ
で呑込んでしまうためコントラスト比が低くなってしま
う。また投写型液晶表示装置の場合に、投射する環境の
明るさによりコントラストが支配されるため、明るい場
所においては、白表示をできるだけ明るく暗い場所にお
いては黒表示をできるだけ暗くする必要がある。[Problems to be Solved by the Invention] However, when the above-mentioned conventional technology is used in a projection type liquid crystal display device, the white display can be brighter than the conventional TN mode projection type liquid crystal display device because no polarizing plate is used. On the other hand, since the scattered light of the black display is swallowed by the projection lens, the contrast ratio becomes low. In addition, in the case of a projection type liquid crystal display device, the contrast is controlled by the brightness of the environment in which the image is projected, so it is necessary to make the white display as bright as possible in bright places and the black display as dark as possible in dark places.
【０００４】そこで本発明はこのような問題点を解決す
るもので、その目的とするところは投写する周囲環境の
明るさの変化に対し、明るい場所においてはできるだけ
明るい表示ができ、暗い場所に於いては、よりコントラ
ストが高くできる投写型液晶表示装置を提供するところ
にある。[0004] The present invention is intended to solve these problems, and its purpose is to provide a display that is as bright as possible in a bright place, and a display that is as bright as possible in a dark place, in response to changes in the brightness of the surrounding environment. Another object of the present invention is to provide a projection type liquid crystal display device that can provide higher contrast.
【０００５】さらには、投射するスクリ−ンの反射もし
くは透過の能率（ゲイン）の違いに対しても最適なコン
トラストになるような投写型液晶表示装置を提供すると
ころにある。Another object of the present invention is to provide a projection type liquid crystal display device that can provide optimal contrast even with respect to differences in reflection or transmission efficiency (gain) of a screen onto which projection is performed.
【０００６】[0006]
【課題を解決するための手段】本発明の投写型液晶表示
装置は、光の透過もしくは散乱により表示を行なう液晶
表示素子を用いた投写型液晶表示装置において、投写レ
ンズの開口角を、投写環境の明るさもしくはスクリ−ン
のゲインに応じ角度を変える絞り機構を設けたことを特
徴とする。[Means for Solving the Problems] The projection type liquid crystal display device of the present invention uses a liquid crystal display element that performs display by transmitting or scattering light. The screen is characterized by being equipped with an aperture mechanism that changes the angle depending on the brightness of the screen or the gain of the screen.
【０００７】[0007]
【実施例】（実施例１）以下本発明の一実施例を図面に
したがって説明する。[Embodiment] (Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.
【０００８】図１は本発明の投写型液晶表示装置の液晶
表示素子（１００）の断面図で、（ａ）図が電界を印加
しない場合の光散乱状態を示すもので（ｂ）図は、電界
を印加したときの光透過状態を示す。FIG. 1 is a cross-sectional view of a liquid crystal display element (100) of a projection type liquid crystal display device according to the present invention, in which (a) shows the light scattering state when no electric field is applied, and (b) shows the state of light scattering when no electric field is applied. This shows the state of light transmission when an electric field is applied.
【０００９】液晶表示素子（１００）は、２枚の基板に
高分子分散型液晶（１０１）が挟まれて配置される。高
分子分散型液晶（１０１）は液晶及びスポンジ状高分子
からなり、電界に対しては無電界時には液晶分子が界面
に沿って配向するため例えば入射光（１０２）が液晶表
示素子（１００）に入射した場合には、高分子分散型液
晶（１０１）の分子配列は散乱状態であるため、入射側
に戻る方向の後方散乱（１０３）と、透過して散乱する
前方散乱（１０４）とに散乱方向が分かれる。又電界を
印加した場合には、電界方向に液晶分子が整列するため
に透過光（１０５）は入射光（１０２）の強度に対して
減衰することなく前方に透過する。The liquid crystal display element (100) is arranged such that a polymer dispersed liquid crystal (101) is sandwiched between two substrates. The polymer dispersed liquid crystal (101) is made of liquid crystal and a sponge-like polymer, and when there is no electric field, the liquid crystal molecules align along the interface, so that, for example, incident light (102) is directed to the liquid crystal display element (100). When incident, the molecular arrangement of the polymer dispersed liquid crystal (101) is in a scattering state, so the scattering is divided into back scattering (103) that returns to the incident side and forward scattering (104) that passes through and scatters. The direction is divided. Further, when an electric field is applied, the liquid crystal molecules are aligned in the direction of the electric field, so that the transmitted light (105) is transmitted forward without attenuating with respect to the intensity of the incident light (102).
【００１０】これらの透過光の発散強度は、強度ベクト
ル（１０６）を矢印にて表わしたように、電界印加状態
においての強度と、散乱状態での発散強度の比が液晶表
示装置のコントラストとなるため散乱光が透過光に比べ
十分小さいことが望ましい。しかし散乱状態の強度ベク
トルＩ０ は、液晶表示素子のセル厚や入射光の性質に
もよるが一般的には次の式のようになる。As shown by the arrow representing the intensity vector (106), the divergence intensity of these transmitted lights is such that the ratio of the intensity in the electric field applied state to the divergence intensity in the scattered state becomes the contrast of the liquid crystal display device. Therefore, it is desirable that the scattered light be sufficiently smaller than the transmitted light. However, the intensity vector I0 of the scattered state is generally expressed by the following equation, although it depends on the cell thickness of the liquid crystal display element and the properties of the incident light.
【００１１】Ｉ０ ＝ＫＩｃｏｓθ
Ｋ；反射係数
図２は、本発明の投射型液晶表示装置の投写レンズと液
晶ライトバルブの構成を示した構成図である。[0011]I0=KIcosθ
K: Reflection coefficient FIG. 2 is a block diagram showing the structure of the projection lens and liquid crystal light valve of the projection type liquid crystal display device of the present invention.
【００１２】液晶を用いた投射型液晶表示装置の投写レ
ンズの仕様は、一般的には主光線が光軸に対して平行で
あるテレセントリックのレンズを用いている。[0012] The projection lens of a projection type liquid crystal display device using liquid crystal generally uses a telecentric lens whose chief ray is parallel to the optical axis.
【００１３】このレンズの場合に開口比のＦ値は、小さ
いほど開口角が大きく明るいレンズであるが、液晶表示
素子に高分子分散型液晶を用いた場合においては、散乱
状態の画像の非選択状態の時の光の散乱光は、投写レン
ズの開口角（呑込み角）が大きいほど光を呑込んでしま
うためコントラストが低下する。In the case of this lens, the smaller the F value of the aperture ratio, the larger the aperture angle, and the brighter the lens becomes. However, when a polymer dispersed liquid crystal is used for the liquid crystal display element, non-selection of images in the scattering state The contrast of the scattered light in this state decreases because the larger the aperture angle (swallowing angle) of the projection lens is, the more light is swallowed.
【００１４】図２（ａ）に示すように投写レンズ（１３
０）の開口角（１３５）は、液晶ライトバルブ（１３１
）に対してほぼ垂直な主光線（１３２）を有するレンズ
で、液晶の画素電極（図示してない。）に結像されてい
る。As shown in FIG. 2(a), the projection lens (13
The aperture angle (135) of 0) is the same as that of the liquid crystal light valve (131
) with a principal ray (132) that is focused on a pixel electrode (not shown) of the liquid crystal.
【００１５】このレンズの場合の開口比Ｆ値は、絞り機
構（１３３）により変えることが可能で、図２（ａ）の
Ｆ値はおよそ２．５の値であり、開口角（１３５）は２
３度で図２（ｂ）のＦ値はおよそ５．５であり、開口角
（１３５）は１０．５度である。この開口角は、液晶表
示装置の黒表示の散乱光に対し、角度が小さいほどコン
トラストは高くなる。The aperture ratio F value of this lens can be changed by the diaphragm mechanism (133), and the F value in FIG. 2(a) is approximately 2.5, and the aperture angle (135) is 2
At 3 degrees, the F value in FIG. 2(b) is approximately 5.5, and the aperture angle (135) is 10.5 degrees. The smaller the aperture angle, the higher the contrast with respect to the scattered light of black display of the liquid crystal display device.
【００１６】図３は本発明の投写型表示装置の投写光学
系の構成図である。高分子分散型液晶からなる三枚の液
晶ライトバルブ（２００）を用いている。投写光源（２
０１）の光を色分離系（２０２）において三原色に分離
し、それぞれの色ごとに三枚の液晶ライトバルブ（２０
０）で変調し、再び色合成系（２０３）によりフルカラ
ーに合成され、投写レンズ（２０４）により拡大投写さ
れ、スクリーン（２０５）上に画像表示が行われる。色
分離系（２０２）及び色合成系（２０３）はそれぞれ二
枚のダイクロイックミラーと反射ミラーから構成されて
おり、波長特性は任意に決めることができる。絞り機構
（２０６）は、図２にに示した絞り量の連続的に可変可
能な絞り機構で周囲環境の光量に対して可変させる。FIG. 3 is a block diagram of the projection optical system of the projection display apparatus of the present invention. Three liquid crystal light valves (200) made of polymer dispersed liquid crystal are used. Projection light source (2
01) is separated into three primary colors in a color separation system (202), and three liquid crystal light valves (20
0), are synthesized again in full color by a color synthesis system (203), enlarged and projected by a projection lens (204), and an image is displayed on a screen (205). The color separation system (202) and the color synthesis system (203) each consist of two dichroic mirrors and a reflection mirror, and the wavelength characteristics can be arbitrarily determined. The diaphragm mechanism (206) is a diaphragm mechanism that can continuously vary the amount of aperture shown in FIG. 2, and is variable in accordance with the amount of light in the surrounding environment.
【００１７】なお、液晶ライトバルブ（２００）はＴＦ
Ｔや、ＭＩＭ方式のアクティブ素子を用いたものや時分
割駆動等のマトリクスアドレス駆動方式に有効で、光や
熱によるアドレス駆動方式にも有効である。[0017] The liquid crystal light valve (200) is a TF
This method is effective for matrix address driving methods such as those using T, MIM type active elements, and time-division driving, and is also effective for address driving methods using light or heat.
【００１８】図４は、本発明の投写型液晶表示装置の周
囲環境に対するコントラストやスクリ−ンのゲインに対
して自動補正の可能な投写型液晶表示装置の実施例を示
すもので、図４（ａ）は構成図、図４（ｂ）は絞り機構
の回路図である。FIG. 4 shows an embodiment of a projection type liquid crystal display device according to the present invention, which is capable of automatically correcting the contrast with respect to the surrounding environment and the gain of the screen. 4(a) is a configuration diagram, and FIG. 4(b) is a circuit diagram of the aperture mechanism.
【００１９】照明光（４００）は、一般的に天井照明が
多く、投写型液晶表示装置の本体（４０１）に取り付け
られた光センサ（４０２）は上部に向けて取り付けられ
ている。 光センサ（４０２）はフォトトランジスタ
やフォトダイオ−ド等から構成されたセンサで、センス
アンプ（４０３）に接続され、照明光の明るさに比例し
た電気信号に変換され、モ−タコントロ−ル回路（４０
４）に入力される。このモ−タコントロ−ル回路はモ−
タ（４０５）に接続され、投写レンズの絞り機構（４０
６）の絞り量を環境の明るさに対して、明るいときは絞
りを解放方向にコントロ−ルし、暗いときには、絞りを
絞る方向にコントロ−ルする。The illumination light (400) generally comes from ceiling lighting, and the optical sensor (402) attached to the main body (401) of the projection type liquid crystal display device is attached toward the top. The optical sensor (402) is a sensor composed of a phototransistor, a photodiode, etc., and is connected to a sense amplifier (403), which converts it into an electrical signal proportional to the brightness of the illumination light, and sends it to the motor control circuit. (40
4) is input. This motor control circuit
is connected to the aperture mechanism (405) of the projection lens.
6) The amount of aperture is controlled in the direction of opening the aperture when the environment is bright, and the amount of aperture is controlled in the direction of closing the aperture when it is dark.
【００２０】スクリ−ン（４０８）は、反射型スクリ−
ンであるがこの反射面の加工方法や形状によりスクリ−
ンゲインが異なるため、このスクリ−ンゲインに対して
投写レンズの絞り量を換えるためゲイン調整つまみ（４
０７）によりゲインを設定する。このゲイン調整摘み（
４０７）は、センスアンプ（４０３）のバイアス電圧を
コントロ−ルする可変抵抗（４０９）に接続され、スク
リ−ンゲインに対してモ−タをコントロ−ルする。The screen (408) is a reflective screen.
However, depending on the processing method and shape of this reflective surface, the screen
Since the screen gain is different, use the gain adjustment knob (4) to change the aperture amount of the projection lens for this screen gain.
07) to set the gain. This gain adjustment knob (
407) is connected to a variable resistor (409) that controls the bias voltage of the sense amplifier (403), and controls the motor with respect to the screen gain.
【００２１】本実施例では液晶表示素子に高分子分散型
液晶を用いたが、この高分子分散型液晶はスポンジ状高
分子の内部に不連続な状態で液晶が存在し、その基本動
作は、例えば日経エレクトロニクス１９９０年６月１１
日号１０２頁に示されるように粒状の液晶の屈折率をス
ポンジ状高分子に合わせておく。すると電圧が印加され
ないときは、界面に沿って液晶分子が配向し光の入射方
向の屈折率が異なるため、反射を繰り返し光は散乱する
。また電圧が印加されるときは、液晶分子が光の入射方
向に配向し屈折率が等しくなるため光が透過する。In this embodiment, a polymer-dispersed liquid crystal was used for the liquid crystal display element. In this polymer-dispersed liquid crystal, liquid crystal exists in a discontinuous state inside a sponge-like polymer, and its basic operation is as follows. For example, Nikkei Electronics June 11, 1990
As shown on page 102 of the issue, the refractive index of the granular liquid crystal is matched to that of the sponge-like polymer. Then, when no voltage is applied, the liquid crystal molecules are aligned along the interface and the refractive index in the direction of light incidence is different, so the light is repeatedly reflected and scattered. Furthermore, when a voltage is applied, the liquid crystal molecules are aligned in the direction of light incidence and the refractive index becomes equal, allowing light to pass through.
【００２２】また高分子分散型液晶はＰＮＬＣ（Ｐｏｌ
ｙｍｅｒ−Ｎｅｔｗｏｒｋ Ｌｉｑｕｉｄ Ｃｒｙｓ
ｔａｌ）で置き換えてもよい。これは液晶層に高分子の
ネットワークを組んだ構造で、液晶が連続な状態で存在
し、液晶分子配向の不規則性を利用する。電圧印加しな
い状態では液晶分子の配向が不規則なため光は散乱し、
電圧印加状態では配向が均一となり光は透過する。Furthermore, the polymer dispersed liquid crystal is PNLC (Pol
ymer-Network Liquid Crys
tal). This has a structure in which a polymer network is assembled in the liquid crystal layer, where the liquid crystal exists in a continuous state and takes advantage of the irregular orientation of the liquid crystal molecules. When no voltage is applied, the orientation of liquid crystal molecules is irregular, so light is scattered.
When a voltage is applied, the orientation is uniform and light is transmitted.
【００２３】[0023]
【発明の効果】以上述べたように本発明によれば、光の
透過もしくは散乱により表示を行なう液晶表示素子を用
いた投写型液晶表示装置において、投写レンズの開口角
を、投写環境の明るさ、もしくはスクリ−ンのゲインに
応じ角度を変える絞り機構を設けたことにより、明るい
環境に於いてはより白方向の画像を明るく確認すること
ができ、また暗室などの暗い部屋に於いては、最も重要
であるコントラストを絞り機構により高めることができ
黒表示側をできるだけ沈めた良品質な画像を提供するこ
とが出来る。As described above, according to the present invention, in a projection type liquid crystal display device using a liquid crystal display element that performs display by transmitting or scattering light, the aperture angle of the projection lens is adjusted depending on the brightness of the projection environment. Or, by installing an aperture mechanism that changes the angle according to the screen gain, it is possible to see a brighter image in the white direction in a bright environment, and in a dark room such as a dark room. The most important contrast can be increased by the diaphragm mechanism, and a high-quality image with the black display side depressed as much as possible can be provided.
【００２４】また本実施例は反射型スクリ−ンの実施例
を示したが、背面投写型のリア型スクリ−ンにおいても
同様の効果が得られる。Further, although this embodiment shows an example of a reflective screen, similar effects can be obtained with a rear projection type screen.
【図１】本発明の投写型液晶表示装置を構成する液晶表
示素子の一実施例を示す断面図で、（ａ）図は電界を印
加しない場合の断面図、（ｂ）図は電界を印加した場合
の断面図である。FIG. 1 is a cross-sectional view showing one embodiment of a liquid crystal display element constituting a projection type liquid crystal display device of the present invention, in which (a) is a cross-sectional view when no electric field is applied, and (b) is a cross-sectional view when an electric field is applied. FIG.
【図２】本発明の投写型液晶表示装置を構成する投写レ
ンズと液晶ライトバルブの構成を示した光線追跡図で、
（ａ）図はＦ値が２．５の光線追跡図、（ｂ）図は、Ｆ
値が５．５の光線追跡図である。FIG. 2 is a ray tracing diagram showing the configuration of a projection lens and a liquid crystal light valve that constitute the projection type liquid crystal display device of the present invention.
(a) The figure is a ray tracing diagram with an F value of 2.5, (b) the figure is F
It is a ray tracing diagram with a value of 5.5.
【図３】本発明の投写型液晶表示装置を液晶表示素子を
三枚用いて、フルカラーとした場合の投写光学系の構成
図である。FIG. 3 is a configuration diagram of a projection optical system when the projection type liquid crystal display device of the present invention is made full color by using three liquid crystal display elements.
【図４】本発明の投写型液晶表示装置の周囲環境に対す
るコントラストや、スクリ−ンのゲインに対して自動補
正の可能な投写型液晶表示装置の実施例を示すもので、
図４（ａ）は構成図、図４（ｂ）は絞り機構の回路図で
ある。FIG. 4 shows an embodiment of the projection type liquid crystal display device of the present invention, which can automatically correct the contrast with respect to the surrounding environment and the gain of the screen.
FIG. 4(a) is a configuration diagram, and FIG. 4(b) is a circuit diagram of the aperture mechanism.
１００・・・液晶表示素子 １０１・・・高分子分散型液晶 １０２・・・入射光 １０３・・・後方散乱 １０４・・・全方散乱 １０５・・・透過光 １０６・・・強度ベクトル １３０・・・投写レンズ １３１・・・液晶ライトバルブ １３２・・・主光線 １３３・・・絞り機構 １３５・・・開口角 ２０１・・・投射光源 ２０２・・・色分離系 ２０３・・・色合成系 ２０５・・・スクリ−ン ４００・・・照明光 ４０１・・・本体 ４０２・・・光センサ ４０３・・・センスアンプ ４０４・・・モ−タコントロ−ル回路 ４０５・・・モ−タ ４０７・・・ゲイン調整摘み ４０９・・・可変抵抗 100...Liquid crystal display element 101...Polymer dispersed liquid crystal 102...Incoming light 103...Backscatter 104...All scattering 105...Transmitted light 106...Intensity vector 130...projection lens 131...LCD light bulb 132...chief ray 133...Aperture mechanism 135...Aperture angle 201...Projection light source 202...Color separation system 203...Color synthesis system 205...Screen 400...Illumination light 401...Main body 402... Optical sensor 403...Sense amplifier 404...Motor control circuit 405...Motor 407...Gain adjustment knob 409...variable resistance
Claims (1)
なう液晶表示素子を用いた投写型液晶表示装置において
、投写レンズの開口角を、投写環境の明るさもしくはス
クリ−ンのゲインに応じ角度を変える絞り機構を設けた
ことを特徴とする投写型液晶表示装置。Claim 1: In a projection type liquid crystal display device using a liquid crystal display element that performs display by transmitting or scattering light, the aperture angle of the projection lens is changed depending on the brightness of the projection environment or the gain of the screen. A projection type liquid crystal display device characterized by being provided with an aperture mechanism.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3057149A JP2953084B2 (en) | 1991-03-20 | 1991-03-20 | Projection display device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3057149A JP2953084B2 (en) | 1991-03-20 | 1991-03-20 | Projection display device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04291333A true JPH04291333A (en) | 1992-10-15 |
| JP2953084B2 JP2953084B2 (en) | 1999-09-27 |
Family
ID=13047514
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3057149A Expired - Lifetime JP2953084B2 (en) | 1991-03-20 | 1991-03-20 | Projection display device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2953084B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5519518A (en) * | 1993-12-27 | 1996-05-21 | Kabushiki Kaisha Toshiba | Display apparatus with a variable aperture stop means on each side of the modulator |
| US5597223A (en) * | 1993-12-27 | 1997-01-28 | Kabushiki Kaisha Toshiba | Display apparatus |
| WO2001019092A1 (en) * | 1999-09-02 | 2001-03-15 | Koninklijke Philips Electronics N.V. | Method of and device for generating an image having a desired brightness |
| US6923546B2 (en) * | 2001-01-12 | 2005-08-02 | Canon Kabushiki Kaisha | Projection optical system and projection type display apparatus using the same |
-
1991
- 1991-03-20 JP JP3057149A patent/JP2953084B2/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5519518A (en) * | 1993-12-27 | 1996-05-21 | Kabushiki Kaisha Toshiba | Display apparatus with a variable aperture stop means on each side of the modulator |
| US5597223A (en) * | 1993-12-27 | 1997-01-28 | Kabushiki Kaisha Toshiba | Display apparatus |
| WO2001019092A1 (en) * | 1999-09-02 | 2001-03-15 | Koninklijke Philips Electronics N.V. | Method of and device for generating an image having a desired brightness |
| US6923546B2 (en) * | 2001-01-12 | 2005-08-02 | Canon Kabushiki Kaisha | Projection optical system and projection type display apparatus using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2953084B2 (en) | 1999-09-27 |
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