JPH0572417A - Polarized light converting element - Google Patents
Polarized light converting elementInfo
- Publication number
- JPH0572417A JPH0572417A JP23671591A JP23671591A JPH0572417A JP H0572417 A JPH0572417 A JP H0572417A JP 23671591 A JP23671591 A JP 23671591A JP 23671591 A JP23671591 A JP 23671591A JP H0572417 A JPH0572417 A JP H0572417A
- Authority
- JP
- Japan
- Prior art keywords
- light
- polarized light
- polarization
- conversion element
- incident
- 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
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
- G02B27/283—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising used for beam splitting or combining
- G02B27/285—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising used for beam splitting or combining comprising arrays of elements, e.g. microprisms
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Polarising Elements (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、偏光変換素子に関し、
特に光源から出射される不定偏光光を効率良く直線偏光
光に変換することが可能な偏光変換素子に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarization conversion element,
In particular, it relates to a polarization conversion element capable of efficiently converting indefinite polarized light emitted from a light source into linearly polarized light.
【0002】[0002]
【従来の技術】偏光光を使用する機器その他の装置に
は、直線偏光光を利用するものがある。直線偏光光を利
用する装置の一例は、TN(ツイステッド・ネマティッ
ク)液晶表示素子の表示画像を、光源と投射レンズを用
いて、スクリーン上に拡大投射する投射型液晶表示装置
である。2. Description of the Related Art Some devices and other devices that use polarized light utilize linearly polarized light. An example of a device that uses linearly polarized light is a projection type liquid crystal display device that magnifies and projects a display image of a TN (twisted nematic) liquid crystal display element on a screen by using a light source and a projection lens.
【0003】従来、このような装置において、光源とし
てハロゲンランプ,キセノンランプ,メタルハライドラ
ンプ等を使用する場合、それらの光源から発生する光は
不定偏光光であり、従って、直線偏光光を得るには、偏
光素子が用いられている。Conventionally, when a halogen lamp, a xenon lamp, a metal halide lamp or the like is used as a light source in such a device, the light generated from these light sources is indefinite polarized light, and therefore, to obtain linearly polarized light. , A polarizing element is used.
【0004】一例として、このような偏光素子として
は、ポリビニルアルコールフィルムに沃素等を配向させ
て吸着させることにより偏光膜を作製し、両面に保護の
ためプラスチックシートやガラス板等を接着した構造の
偏光板が用いられている。また、二つの直角プリズムの
一方の斜面に半透膜をコートして斜面どおしを接合し、
透過光と反射光とを互いに偏光方向が直交する直線偏光
光として取り出す偏光ビームスプリッタも用いられてい
る。As an example of such a polarizing element, a polarizing film is prepared by orienting and adsorbing iodine or the like on a polyvinyl alcohol film, and a plastic sheet or glass plate is adhered on both sides for protection. A polarizing plate is used. In addition, one of the two right-angle prisms is coated with a semi-permeable membrane on one slope, and the slopes are joined together.
There is also used a polarization beam splitter that extracts transmitted light and reflected light as linearly polarized light whose polarization directions are orthogonal to each other.
【0005】しかし、このような偏光板や偏光ビームス
プリッタ等の偏光素子を、ハロゲンランプ等の光源に使
用する場合、不用な偏光成分の光を吸収、あるいは反射
してしまうため、光源からの光束の光利用効率は50%
以下と低くならざるを得なかったので、光の損失が大き
いという問題がある。この問題は、例えば使用装置が投
射型液晶表示装置の場合には、所要の明るさの投射画面
を確保しようとするときには、その光源として、より精
度の高いものの使用を要求することとなる。However, when such a polarizing element such as a polarizing plate or a polarizing beam splitter is used for a light source such as a halogen lamp, it absorbs or reflects light of an unnecessary polarization component, so that a light flux from the light source is emitted. Light utilization efficiency is 50%
Since it had to be lower than the following, there was a problem that the loss of light was large. For example, when the device used is a projection type liquid crystal display device, this requires a more accurate light source to be used as a light source when a projection screen having a required brightness is to be secured.
【0006】すなわち、既述したように、直線偏光光を
利用する装置の一例として、TN(ツイステッド・ネマ
ティック)液晶表示素子の表示画像を、光源と投射レン
ズを用いて、スクリーン上に拡大投射する投射型液晶表
示装置があるが、液晶表示素子の光の入出射面に偏光板
を配置する構成を採用した場合、光源からの光束の透過
率は偏光板だけでも40%以下になってしまう。さら
に、液晶表示素子は、液晶や透明電極等の吸収、境界面
での反射、開口率等により、偏光板を含めた素子全体の
透過率は、かなり低い値にならざるを得なかった。この
ため、明るい投射画面を得るためには、光源に輝度の高
いものを使用しなくてはならない。That is, as described above, as an example of a device using linearly polarized light, a display image of a TN (twisted nematic) liquid crystal display device is enlarged and projected on a screen by using a light source and a projection lens. Although there is a projection type liquid crystal display device, when a configuration in which a polarizing plate is arranged on the light incident / exiting surface of the liquid crystal display element is adopted, the transmittance of the light flux from the light source is 40% or less even with the polarizing plate alone. Further, in the liquid crystal display element, the transmittance of the entire element including the polarizing plate has to be a considerably low value due to absorption of liquid crystal, transparent electrodes, etc., reflection at the boundary surface, aperture ratio and the like. Therefore, in order to obtain a bright projection screen, a light source with high brightness must be used.
【0007】輝度の高い光源が要求されれば、偏光板を
使用して直線偏光光を得る場合における光利用効率が低
いという問題は、それに留まらず、使用装置の消費電力
の増大、発熱による温度上昇、それに伴う偏光板や液晶
表示素子の性能低下や劣化、温度上昇を抑えるために使
用する空冷ファンからの騒音発生等にまで波及すること
になる。If a light source with high brightness is required, the problem of low light utilization efficiency in the case of using a polarizing plate to obtain linearly polarized light is not limited to the above problem. This will affect the temperature rise, the deterioration and deterioration of the performance of the polarizing plate and the liquid crystal display element, and the noise generation from the air-cooling fan used to suppress the temperature rise.
【0008】従来、このような偏光板による光量損失を
低減し、光源の光利用効率を向上させる技術として、例
えば特開昭59−127019号公報に開示されている
様に、液晶シャッタ等の光学変調素子を用いるプリンタ
ヘッドにおいて、偏光ビームスプリッタ,反射ミラー,
および1/2波長板を用いた照明方法が提案されてい
る。この照明方法は、照明光束を偏光ビームスプリッタ
に入射させ、互いに偏光方向が直交する2つの直線偏光
光束に分離した後、一方の光束をそのまま液晶シャッタ
に入射させ、他方の光束については、1/2波長板で偏
光方向を90度回転させ、一方の光束の偏光方向と等し
くするとともに、反射ミラーを用いて液晶シャッタに光
束を入射させることで、照明光の光利用効率の向上を実
現している。Conventionally, as a technique for reducing the light amount loss due to such a polarizing plate and improving the light utilization efficiency of the light source, as disclosed in, for example, Japanese Patent Application Laid-Open No. 59-127019, an optical element such as a liquid crystal shutter is used. In a printer head using a modulator, a polarization beam splitter, a reflection mirror,
An illumination method using a half-wave plate has been proposed. According to this illumination method, an illumination light beam is made incident on a polarization beam splitter, separated into two linearly polarized light beams whose polarization directions are orthogonal to each other, one light beam is made incident on a liquid crystal shutter as it is, and the other light beam is 1 / By rotating the polarization direction by 90 degrees with the two-wave plate to make it equal to the polarization direction of one light flux, and by making the light flux enter the liquid crystal shutter using the reflection mirror, the light utilization efficiency of the illumination light is improved. There is.
【0009】[0009]
【発明が解決しようとする課題】しかし、従来の照明方
法を投射型液晶表示装置に適用すると、照明光の光束径
が大きいので、大きな偏光ビームスプリッタを用いるこ
とが要求され、投射装置の大きさや重さ,製造コストに
影響を与えるのみならず、偏光ビームスプリッタで分離
した2光束を再び合成する時の合成角度が大きくなると
いう問題点が生じる。2光束の合成角度が大きくなると
いう問題点は、投射型液晶表示装置において、光の透
過,反射特性に入射角依存性のある液晶表示素子や光学
素子を用いているため投射画像の画質が劣化したり、投
射レンズの口径食により投射画像が暗くなるという不具
合を生じさせる。投射レンズで口径食が生じないように
するには、大きな口径の投射レンズが必要であり、投射
装置の大型化,製造コストの上昇を伴う。また、2光束
の合成角度を小さくするには、照明光の光路を長くしな
ければならず、装置が大きくなってしまうことや、照明
光束が発散するので、結局光利用効率が向上しないこと
になる。However, when the conventional illuminating method is applied to the projection type liquid crystal display device, since the luminous flux diameter of the illuminating light is large, it is required to use a large polarization beam splitter. This not only affects the weight and manufacturing cost, but also causes a problem that the combining angle becomes large when the two light beams separated by the polarization beam splitter are combined again. The problem that the combined angle of the two light fluxes becomes large is that the image quality of the projected image is deteriorated in the projection type liquid crystal display device because the liquid crystal display element or the optical element having the incident angle dependency on the light transmission and reflection characteristics is used. Or the vignetting of the projection lens causes the projected image to become dark. In order to prevent vignetting in the projection lens, a projection lens with a large aperture is required, which causes an increase in the size of the projection device and an increase in manufacturing cost. Also, in order to reduce the combined angle of the two light fluxes, the optical path of the illumination light must be lengthened, the device becomes large, and the illumination light flux diverges, so that the light utilization efficiency is not improved. Become.
【0010】本発明の目的は、光源から出射される不定
偏光光を効率良く直線偏光光に変換することが可能であ
り、特に投射型液晶表示装置に用いる場合、偏光板や液
晶表示素子の劣化、投射画像の画質劣化,装置の大型
化、大幅な製造コストの上昇を伴わずに、投射画像の高
輝度化に有効な偏光変換素子を提供することにある。An object of the present invention is to efficiently convert indefinitely polarized light emitted from a light source into linearly polarized light, and particularly when it is used for a projection type liquid crystal display device, deterioration of a polarizing plate or a liquid crystal display element is caused. Another object of the present invention is to provide a polarization conversion element effective for increasing the brightness of a projected image without degrading the image quality of the projected image, increasing the size of the apparatus, and significantly increasing the manufacturing cost.
【0011】[0011]
【課題を解決するための手段】上記目的を達成するため
に、本発明の偏光変換素子は、光束の幅を一方向のみ半
分に縮小する光束幅変換素子と、前記光束幅変換素子か
らの出射光を互いに偏光方向が直交するp偏光光とs偏
光光の2つの直線偏光光に分離する偏光分離面を、前記
光束幅変換素子の光束幅を縮小する方向と前記s偏光光
の反射方向とが平行になるように形成した偏光ビームス
プリッタと、前記偏光分離面と互いに平行な光束反射面
を有し、前記s偏光光の反射方向に前記偏光ビームスプ
リッタと隣接して配置した光束反射素子と、前記偏光ビ
ームスプリッタで分離されたp偏光光とs偏光光とs偏
光光のどちらか一方の光路に配置した1/2波長板とを
構成要素とし、前記構成要素を単独で、または2組以上
を並列に配置して構成されることを特徴としている。In order to achieve the above object, a polarization conversion element of the present invention comprises a light flux width conversion element for reducing the width of a light flux to half in one direction and an output from the light flux width conversion element. A polarization splitting surface that splits the emitted light into two linearly polarized light beams of p-polarized light and s-polarized light whose polarization directions are orthogonal to each other is provided with a direction for reducing the luminous flux width of the luminous flux width conversion element and a reflection direction for the s-polarized light. A polarization beam splitter formed to be parallel to each other, and a light beam reflection element having a light beam reflection surface parallel to the polarization splitting surface and arranged adjacent to the polarization beam splitter in a reflection direction of the s-polarized light. , A half-wave plate disposed in the optical path of either p-polarized light, s-polarized light, or s-polarized light separated by the polarization beam splitter is used as a constituent element, and the constituent elements are used alone or in two sets. Place the above in parallel It is characterized by being made.
【0012】[0012]
【作用】本発明の上記構成によれば、光源からの不定偏
光光である出射光束を偏光変換素子に入射させると、そ
の入射光束は、光束幅変換素子により光束の幅を一方向
のみ半分に縮小される。縮小された光束は偏光ビームス
プリッタに入射しその偏光分離面において、p偏光成分
の光はそのまま透過し、s偏光成分の光は反射されるこ
とにより、互いに偏光方向が直交する2つの直線偏光光
に分離される。反射したs偏光光は、隣接する光束反射
素子の光束反射面で反射される。光束反射素子の光束反
射面は、偏光ビームスプリッタの偏光分離面と互いに平
行に配置しているので、s偏光光はp偏光の進行方向と
同一方向に並列して出射することになり、光束幅変換素
子で半分に縮小された入射光束は再びもとの光束幅と等
しくなる。さらに、1/2波長板は入射直線偏光光の偏
光方向を90度回転させて出射させる作用があるので、
p偏光光とs偏光光のうち1/2波長板が光路に配置さ
れた一方の直線偏光光の偏光方向は、1/2波長板を透
過することで、他方の直線偏光光の偏光方向と等しくな
る。したがって、光源からの不定偏光光を偏光変換素子
に入射させると、偏光変換素子からの出射光は、入射光
と進行方向、並びに光束幅が等しく、かつ偏光方向が特
定の方向に揃った直線偏光光に効率良く変換されること
になる。According to the above configuration of the present invention, when the outgoing light flux which is the indefinite polarized light from the light source is incident on the polarization conversion element, the incident light flux is halved in only one direction by the light flux width conversion element. It is reduced. The reduced light beam enters the polarization beam splitter, and the p-polarized component light is transmitted as it is on the polarization separation surface thereof, and the s-polarized component light is reflected, so that two linearly polarized light beams whose polarization directions are orthogonal to each other. Is separated into The reflected s-polarized light is reflected by the light flux reflecting surface of the adjacent light flux reflecting element. Since the light flux reflecting surface of the light flux reflecting element is arranged in parallel to the polarization splitting surface of the polarization beam splitter, the s-polarized light is emitted in parallel in the same direction as the traveling direction of the p-polarized light. The incident light flux reduced to half by the conversion element becomes equal to the original light flux width again. Furthermore, since the half-wave plate has the function of rotating the polarization direction of the incident linearly polarized light by 90 degrees and outputting it,
Of the p-polarized light and the s-polarized light, the polarization direction of the one linearly polarized light having the half-wave plate arranged in the optical path is the same as the polarization direction of the other linearly polarized light by passing through the half-wave plate. Will be equal. Therefore, when indefinite polarized light from the light source is incident on the polarization conversion element, the output light from the polarization conversion element is linearly polarized light in which the incident light has the same traveling direction and the same luminous flux width, and the polarization direction is aligned in a specific direction. It will be converted into light efficiently.
【0013】また、上記構成要素を2組以上を並列に配
置する構成の場合には、光束幅変換素子と偏光ビームス
プリッタの厚みを薄くすることができ、偏光変換素子の
小型,軽量化が可能になる。Further, in the case of a configuration in which two or more sets of the above-mentioned components are arranged in parallel, the thickness of the light beam width conversion element and the polarization beam splitter can be made thin, and the polarization conversion element can be made small and lightweight. become.
【0014】[0014]
【実施例】以下、本発明の実施例について図面を参照し
て説明する。Embodiments of the present invention will be described below with reference to the drawings.
【0015】図1は、本発明の第1の実施例を示す偏光
変換素子の平面図である。図1に示すように、本実施例
の偏光変換素子は、光束幅変換素子1と、偏光ビームス
プリッタ2と、光束反射素子3と、1/2波長板4とか
ら構成される。光束幅変換素子1と偏光ビームスプリッ
タ2は、光軸が同一であり、光束幅変換素子1からの出
射光11が偏光ビームスプリッタ2に入射するように配
置される。また、偏光ビームスプリッタ2は、偏光分離
面7において反射されるs偏光光13の反射方向が光束
幅変換素子1において光束幅を縮小する方向と平行にな
るように配置される。光束反射素子3は、s偏光光13
の反射方向に偏光ビームスプリッタ2と隣接し、かつ光
束反射面8が偏光分離面7と平行になるように配置され
る。1/2波長板4は、s偏光光13の光路中に配置さ
れる。FIG. 1 is a plan view of a polarization conversion element showing a first embodiment of the present invention. As shown in FIG. 1, the polarization conversion element of this embodiment includes a light flux width conversion element 1, a polarization beam splitter 2, a light flux reflection element 3, and a ½ wavelength plate 4. The light flux width conversion element 1 and the polarization beam splitter 2 have the same optical axis, and are arranged so that the emitted light 11 from the light flux width conversion element 1 enters the polarization beam splitter 2. The polarization beam splitter 2 is arranged such that the reflection direction of the s-polarized light 13 reflected by the polarization splitting surface 7 is parallel to the direction in which the light flux width is reduced in the light flux width conversion element 1. The light flux reflecting element 3 is configured to reflect the s-polarized light 13
Is arranged so as to be adjacent to the polarization beam splitter 2 in the reflection direction of and the light flux reflecting surface 8 is parallel to the polarization splitting surface 7. The half-wave plate 4 is arranged in the optical path of the s-polarized light 13.
【0016】次に図1に示した構成の、本発明に従う偏
光変換素子の原理を説明する。例えばキセノンランプや
ハロゲンランプ等の白色光源からの出射光は不定偏光光
であり、そのような出射光を偏光変換素子の入射光10
とする。入射光10は、一方向のみ屈折力のあるシリン
ドリカルレンズ5,6からなる光束幅変換素子1により
光束の幅を一方向のみ半分に縮小される。光束幅を縮小
された出射光11は、偏光ビームスプリッタ2に入射
し、偏光ビームスプリッタ2に形成された偏光分離面7
において、p偏光光はそのまま透過し、s偏光光13は
反射することにより、互いに偏光方向が直交する2つの
直線偏光光に分離される。ここでp偏光光12の偏光方
向は紙面に平行、s偏光光13の偏光方向は紙面に垂直
である。反射したs偏光光13は、隣接する光束反射素
子3の光束反射面8で反射される。光束反射面8は偏光
ビームスプリッタ2の偏光分離面7と互いに平行に配置
しているので、s偏光光13の光束反射素子3による反
射光15の進行方向は、p偏光光12の進行方向と平行
になる。したがって、偏光変換素子からの出射光14,
16は、並列して平行に出射することになり、光束幅変
換素子1で一度半分に縮小された光束の幅は、再び入射
光10の光束幅と等しくなる。さらに、1/2波長板4
は入射直線偏光光の偏光方向を90度回転させて出射さ
せる作用があるので、1/2波長板4が光路に配置され
たs偏光光13の偏光方向は、1/2波長板4を透過す
ることで、p偏光12の偏光方向と等しくなる。結果と
して、光源からの不定偏光光を偏光変換素子に入射させ
ると、偏光変換素子からの出射光14,16は、入射光
10と進行方向、並びに光束幅が等しく、かつ偏光方向
が特定の方向に揃った直線偏光光に効率良く変換される
ことになるので、本発明の構成に従えば、光源から出射
される不定偏光光を効率良く直線偏光光に変換する偏光
変換素子を得ることが可能になる。Next, the principle of the polarization conversion element according to the present invention having the configuration shown in FIG. 1 will be described. For example, the emitted light from a white light source such as a xenon lamp or a halogen lamp is indefinite polarized light, and such emitted light is incident on the polarization conversion element.
And Incident light 10 has its luminous flux width reduced to half in one direction by a luminous flux width conversion element 1 including cylindrical lenses 5 and 6 having a refractive power in only one direction. The outgoing light 11 having the reduced luminous flux width is incident on the polarization beam splitter 2, and the polarization splitting surface 7 formed on the polarization beam splitter 2
In, the p-polarized light is transmitted as it is, and the s-polarized light 13 is reflected to be separated into two linearly polarized lights whose polarization directions are orthogonal to each other. Here, the polarization direction of the p-polarized light 12 is parallel to the paper surface, and the polarization direction of the s-polarized light 13 is perpendicular to the paper surface. The reflected s-polarized light 13 is reflected by the light flux reflecting surface 8 of the adjacent light flux reflecting element 3. Since the light flux reflecting surface 8 is arranged in parallel with the polarization splitting surface 7 of the polarization beam splitter 2, the traveling direction of the s-polarized light 13 reflected by the light flux reflecting element 3 is the same as that of the p-polarized light 12. Become parallel. Therefore, the outgoing light 14 from the polarization conversion element,
The light beams 16 are emitted in parallel in parallel, and the width of the light beam once reduced to half by the light beam width conversion element 1 becomes equal to the light beam width of the incident light 10 again. Furthermore, 1/2 wavelength plate 4
Has a function of rotating the polarization direction of the incident linearly polarized light by 90 degrees and emitting the same, the polarization direction of the s-polarized light 13 having the half-wave plate 4 arranged in the optical path is transmitted through the half-wave plate 4. By doing so, it becomes equal to the polarization direction of the p-polarized light 12. As a result, when the indefinite polarized light from the light source is incident on the polarization conversion element, the outgoing lights 14 and 16 from the polarization conversion element have the same traveling direction and the same luminous flux width as the incident light 10, and the polarization direction is a specific direction. Therefore, according to the configuration of the present invention, it is possible to obtain a polarization conversion element that efficiently converts indefinite polarized light emitted from a light source into linearly polarized light. become.
【0017】図1に示した構成は、光束幅変換素子1と
して2枚のシリンドリカルレンズ5,6を用い、また1
/2波長板4をs偏光光13の光路中に配置した場合の
態様の一例を示したものであり、以下、これについて更
に具体的に説明する。The configuration shown in FIG. 1 uses two cylindrical lenses 5 and 6 as the light beam width conversion element 1, and
1 shows an example of a mode in which the / 2 wavelength plate 4 is arranged in the optical path of the s-polarized light 13, which will be described more specifically below.
【0018】図1の構成において使用した光束幅変換素
子1、偏光ビームスプリッタ2、光束反射素子3、1/
2波長板4は、それぞれ具体的には次のようなものであ
る。The light flux width conversion element 1, the polarization beam splitter 2, the light flux reflection element 3, 1 / used in the configuration of FIG.
The two wave plates 4 are specifically as follows.
【0019】光束幅変換素子1としては、2枚のシリン
ドリカルレンズ5,6を用いた。シリンドリカルレンズ
5は平凸レンズ、シリンドリカルレンズ6は平凹レンズ
であり、焦点距離の比が2:1で、ガリレオ型の配置に
より出射光11の光束幅を、入射光10の光束幅の半分
に縮小した。すなわち、入射光10の光束径50mmφ
に対し、シリンドリカルレンズ5の入射面の大きさは5
0×50mm、焦点距離は150mm、シリンドリカル
レンズ6の入射面の大きさは25×50mm、焦点距離
は−75mmであり、シリンドリカルレンズ5,6の主
点間距離を75mmに配置することにより、光束幅25
mmの出射光11を得た。As the light flux width conversion element 1, two cylindrical lenses 5 and 6 were used. The cylindrical lens 5 is a plano-convex lens and the cylindrical lens 6 is a plano-concave lens. The focal length ratio is 2: 1, and the luminous flux width of the outgoing light 11 is reduced to half the luminous flux width of the incident light 10 by the Galileo type arrangement. .. That is, the luminous flux diameter of the incident light 10 is 50 mmφ
On the other hand, the size of the incident surface of the cylindrical lens 5 is 5
0 × 50 mm, the focal length is 150 mm, the size of the entrance surface of the cylindrical lens 6 is 25 × 50 mm, the focal length is −75 mm, and the principal point distance between the cylindrical lenses 5 and 6 is set to 75 mm Width 25
Output light 11 of mm was obtained.
【0020】偏光ビームスプリッタ2は、2個の直角プ
リズムの一方の斜面に誘電体多層膜からなる半透膜をコ
ートすることで偏光分離面7を形成し、斜面どおしを接
合した構造であり、特に、可視光領域の波長の不定偏光
光に対して、十分にp偏光光12とs偏光光13とに分
離できる性能を有するものを用いた。その消光比、すな
わち透過光のp偏光成分とs偏光成分の光の強度比は、
100:1以上であった。入射面の大きさは25×50
mm、厚さは25mmであり、入射面、および出射面に
は誘電体多層膜からなる反射防止膜を施した。The polarization beam splitter 2 has a structure in which a polarization separating surface 7 is formed by coating a semi-permeable film made of a dielectric multilayer film on one slope of two right-angle prisms, and the slopes are joined together. In particular, the one having the ability to sufficiently separate the p-polarized light 12 and the s-polarized light 13 with respect to the indefinite polarized light having the wavelength in the visible light region was used. The extinction ratio, that is, the intensity ratio of the p-polarized component and the s-polarized component of the transmitted light is
It was 100: 1 or more. The size of the entrance surface is 25 x 50
The thickness was 25 mm, the thickness was 25 mm, and an antireflection film made of a dielectric multilayer film was applied to the entrance surface and the exit surface.
【0021】光束反射素子3は、ガラス基板にアルミニ
ウムを蒸着し、表面に誘電体多層膜からなる増反射コー
トを施したアルミ表面鏡を用いた。As the light flux reflecting element 3, an aluminum surface mirror was used in which aluminum was vapor-deposited on a glass substrate and the surface was subjected to an increased reflection coating made of a dielectric multilayer film.
【0022】1/2波長板4は、特に可視光領域の光に
対し有効に作用するように、ポリビニルアルコールフィ
ルムを延伸し、所望の複屈折性を持たせ、保護ガラスで
挟んだものを使用した。1/2波長板4の光の入出射面
には、誘電体多層膜からなる反射防止膜を施した。The half-wave plate 4 is formed by stretching a polyvinyl alcohol film so as to have a desired birefringence and sandwiching it between protective glasses so as to effectively act on light in the visible light range. did. An antireflection film made of a dielectric multilayer film is applied to the light incident / emission surface of the half-wave plate 4.
【0023】さて、図1の偏光変換素子において、光源
からの不定偏光光が偏光変換素子に入射したとすると、
前記原理説明で述べたように、入射光10は、シリンド
リカルレンズ5,6からなる光束幅変換素子1により光
束の幅を一方向のみ半分に縮小される。光束幅を縮小さ
れた出射光11は、偏光ビームスプリッタ2で、p偏光
光12とs偏光光13の、互いに偏光方向が直交する2
つの直線偏光光に分離される。ここでp偏光光12の偏
光方向は紙面に平行、s偏光光13の偏光方向は紙面に
垂直である。p偏光光12はそのまま偏光変換素子を出
射し、出射光14を得る。s偏光光13は、隣接する光
束反射素子3で反射され、その反射光15の進行方向
は、p偏光光12の進行方向と平行になる。さらに、反
射光15の偏光方向は、1/2波長板4を透過すること
で、p偏光12の偏光方向と等しくなり、偏光変換素子
からの出射光16を得る。Now, in the polarization conversion element of FIG. 1, if indefinite polarized light from the light source enters the polarization conversion element,
As described in the above description of the principle, the incident light 10 has its luminous flux width reduced to half in only one direction by the luminous flux width conversion element 1 including the cylindrical lenses 5 and 6. The outgoing light 11 having the reduced luminous flux width is polarized by the polarization beam splitter 2 and the polarization directions of the p-polarized light 12 and the s-polarized light 13 are orthogonal to each other.
It is split into two linearly polarized lights. Here, the polarization direction of the p-polarized light 12 is parallel to the paper surface, and the polarization direction of the s-polarized light 13 is perpendicular to the paper surface. The p-polarized light 12 is emitted from the polarization conversion element as it is, and emitted light 14 is obtained. The s-polarized light 13 is reflected by the adjacent light beam reflection element 3, and the traveling direction of the reflected light 15 is parallel to the traveling direction of the p-polarized light 12. Furthermore, the polarization direction of the reflected light 15 becomes equal to the polarization direction of the p-polarized light 12 by passing through the half-wave plate 4, and the emitted light 16 from the polarization conversion element is obtained.
【0024】結果として、偏光変換素子からの出射光1
4,16は、入射光10と進行方向、並びに光束幅が等
しく、かつ偏光方向が特定の方向、ここでは紙面に平行
な方向に揃った直線偏光光に変換される。以上の過程に
おいて、光の損失は、媒質の吸収や散乱によって生じ
る、わずかな量である。このように、直線偏光光を得る
場合に本発明に従う図1の偏光変換素子を用いることに
より、効率良く直線偏光光を得ることが可能になる。As a result, the output light 1 from the polarization conversion element 1
4 and 16 are converted into linearly polarized light whose traveling direction is the same as that of the incident light 10 and whose luminous flux width is the same, and whose polarization direction is aligned in a specific direction, which is a direction parallel to the paper surface here. In the above process, the light loss is a slight amount caused by absorption and scattering of the medium. Thus, by using the polarization conversion element of FIG. 1 according to the present invention to obtain linearly polarized light, it is possible to efficiently obtain linearly polarized light.
【0025】図2は、本発明の第2の実施例を示す偏光
変換素子の平面図である。図2に示すように、本実施例
の偏光変換素子は、光束幅変換素子21と、偏光ビーム
スプリッタ22と、光束反射素子23と、1/2波長板
24とを構成要素20とし、その構成要素20を4組並
列に配置して構成される。各構成要素の配置は、1/2
波長板24が偏光ビームスプリッタ22で分離されたp
偏光光の光路に配置していることを除き、第1の実施例
と同様である。FIG. 2 is a plan view of a polarization conversion element showing the second embodiment of the present invention. As shown in FIG. 2, the polarization conversion element of the present embodiment has a light flux width conversion element 21, a polarization beam splitter 22, a light flux reflection element 23, and a ½ wavelength plate 24 as constituent elements 20, and its configuration. It is configured by arranging four sets of the elements 20 in parallel. Arrangement of each component is 1/2
The wave plate 24 is separated by the polarization beam splitter 22 from p
It is similar to the first embodiment except that it is arranged in the optical path of polarized light.
【0026】図2に示した構成は、光束反射素子23と
して直角プリズムを用い、また1/2波長板24をp偏
光光の光路中に配置した場合の態様の一例を示したもの
であり、以下、これについて更に具体的に説明する。The configuration shown in FIG. 2 shows an example of a mode in which a right-angle prism is used as the light flux reflecting element 23 and a ½ wavelength plate 24 is arranged in the optical path of p-polarized light. Hereinafter, this will be described more specifically.
【0027】図2の構成要素20に使用した光束幅変換
素子21,偏光ビームスプリッタ22,光束反射素子2
3,1/2波長板24は、それぞれ具体的には次のよう
なものである。A light flux width conversion element 21, a polarization beam splitter 22, and a light flux reflection element 2 used in the constituent element 20 of FIG.
The 3, 1/2 wave plate 24 is specifically as follows.
【0028】光束幅変換素子21としては、第1の実施
例と同様に2枚のシリンドリカルレンズ25,26を用
いた。本実施例においては、入射光の光束径80mmφ
に対し、4組の各構成要素には、それぞれ20mm幅の
光束が入射することになる。シリンドリカルレンズ25
の入射面の大きさは20×80mm、焦点距離は60m
m、シリンドリカルレンズ26の入射面の大きさは10
×80mm、焦点距離は−30mmであり、シリンドリ
カルレンズ25,26の主点間距離を30mmに配置す
ることにより、光束幅10mmの出射光を得た。As the luminous flux width conversion element 21, two cylindrical lenses 25 and 26 are used as in the first embodiment. In this embodiment, the luminous flux diameter of the incident light is 80 mmφ.
On the other hand, a light flux with a width of 20 mm is incident on each of the four sets of constituent elements. Cylindrical lens 25
The size of the entrance surface is 20 x 80 mm, and the focal length is 60 m
m, the size of the incident surface of the cylindrical lens 26 is 10
By setting the distance between the principal points of the cylindrical lenses 25 and 26 to be 30 mm, the emitted light having a luminous flux width of 10 mm was obtained.
【0029】偏光ビームスプリッタ22は、第1の実施
例と同様の性能を有するものを用いた。入射面の大きさ
は10×80mm、厚さは10mmである。入射面には
誘電体多層膜からなる反射防止膜を施した。The polarization beam splitter 22 used has the same performance as that of the first embodiment. The incident surface has a size of 10 × 80 mm and a thickness of 10 mm. An antireflection film made of a dielectric multilayer film was applied to the incident surface.
【0030】光束反射素子23は、直角プリズムを用い
た。光束反射面は直角プリズムの斜面であり、内部全反
射を利用する形態で使用した。出射面には、反射防止膜
を施した。偏光ビームスプリッタ22とは屈折率の整合
をとって接着したが、この方法に限らず、偏光ビームス
プリッタ22の一方のプリズムを図の形状で一体化して
研磨製作することも可能である。As the light flux reflecting element 23, a rectangular prism is used. The light flux reflecting surface is an inclined surface of a right angle prism and was used in a form utilizing total internal reflection. An antireflection film was applied to the emission surface. The polarizing beam splitter 22 and the polarizing beam splitter 22 are adhered to each other while matching the refractive index, but the present invention is not limited to this method, and one prism of the polarizing beam splitter 22 can be integrally manufactured in the shape shown in the figure for polishing.
【0031】1/2波長板24は、第1の実施例と同様
の性能を有するものを用いた。出射面には、誘電体多層
膜からなる反射防止膜を施した。1/2波長板24と偏
光ビームスプリッタ22とは屈折率の整合をとって接着
した。As the half-wave plate 24, one having the same performance as that of the first embodiment was used. An antireflection film made of a dielectric multilayer film was applied to the emission surface. The half-wave plate 24 and the polarization beam splitter 22 are adhered to each other with matching refractive indexes.
【0032】本実施例の偏光変換素子は、以上の光束幅
変換素子21,偏光ビームスプリッタ22,光束反射素
子23,1/2波長板24とからなる構成要素20を、
4組並列に配置して構成した。したがって、入射光の光
束径80mmφに対し、偏光変換素子の入射面の大きさ
は80×80mmであり、光軸方向の長さは50mmで
あった。The polarization conversion element of the present embodiment includes a constituent element 20 composed of the light flux width conversion element 21, the polarization beam splitter 22, the light flux reflection element 23, and the ½ wavelength plate 24 described above.
Four sets were arranged in parallel. Therefore, the size of the incident surface of the polarization conversion element was 80 × 80 mm, and the length in the optical axis direction was 50 mm with respect to the luminous flux diameter of 80 mmφ of the incident light.
【0033】さて、図2の偏光変換素子において、光源
からの不定偏光光が偏光変換素子に入射した場合、光束
は各構成要素の入射面を断面とする光束に分割される
が、説明を簡単にするため、構成要素20に入射した光
束に着目し、以下、その光路を用いて説明する。Now, in the polarization conversion element of FIG. 2, when indefinite polarized light from the light source enters the polarization conversion element, the light beam is divided into light beams having the incident surface of each component as a cross section. In order to achieve the above, attention is paid to the luminous flux that has entered the constituent element 20, and the optical path thereof will be used in the following description.
【0034】構成要素20に入射した光束は、第1の実
施例で述べたように、シリンドリカルレンズ25,26
からなる光束幅変換素子21により光束の幅を一方向の
み半分に縮小される。光束幅を縮小された出射光は、偏
光ビームスプリッタ22で、p偏光光とs偏光光の、互
いに偏光方向が直交する2つの直線偏光光に分離され
る。ここでp偏光光の偏光方向は紙面に平行、s偏光光
の偏光方向は紙面に垂直である。s偏光光は、隣接する
光束反射素子23で反射され、その反射光の進行方向が
p偏光光の進行方向と平行になり、構成要素20を出射
する。p偏光光は、1/2波長板24を透過すること
で、その偏光方向がs偏光光の偏光方向と等しくなり、
構成要素20から出射する。The luminous flux incident on the constituent element 20 is, as described in the first embodiment, cylindrical lenses 25 and 26.
The beam width conversion element 21 made of reduces the beam width by half in only one direction. The emitted light with the reduced luminous flux width is separated by the polarization beam splitter 22 into two linearly polarized lights of p-polarized light and s-polarized light whose polarization directions are orthogonal to each other. Here, the polarization direction of the p-polarized light is parallel to the paper surface, and the polarization direction of the s-polarized light is perpendicular to the paper surface. The s-polarized light is reflected by the adjacent light flux reflecting element 23, the traveling direction of the reflected light becomes parallel to the traveling direction of the p-polarized light, and exits the constituent element 20. The p-polarized light is transmitted through the half-wave plate 24 so that its polarization direction becomes equal to that of the s-polarized light,
Emitted from the component 20.
【0035】結果として、構成要素20からの出射光
は、入射光と進行方向、並びに光束幅が等しく、かつ偏
光方向が特定の方向、ここでは紙面に垂直な方向に揃っ
た直線偏光光に変換される。As a result, the light emitted from the constituent element 20 is converted into linearly polarized light whose traveling direction is the same as that of the incident light, and whose luminous flux width is equal, and whose polarization direction is aligned in a specific direction, here, the direction perpendicular to the paper surface. To be done.
【0036】他の構成要素に入射した光束についても、
構成要素20に入射した光束と同様に、それらの出射光
は、入射光と進行方向、並びに光束幅が等しく、かつ偏
光方向が特定の方向、ここでは紙面に垂直な方向に揃っ
た直線偏光光に変換される。With respect to the luminous flux incident on the other components,
Similar to the luminous flux incident on the constituent element 20, the emitted light thereof is a linearly polarized light whose traveling direction is equal to that of the incident light, and the luminous flux width is equal, and the polarization direction is aligned in a specific direction, here, a direction perpendicular to the paper surface. Is converted to.
【0037】以上の過程において、光の損失は、媒質の
吸収や散乱によって生じる、わずかな量である。このよ
うに、直線偏光光を得る場合に本発明に従う図2の偏光
変換素子を用いることにより、効率良く直線偏光光を得
ることが可能になる。また、第2の実施例の構成によれ
ば、偏光変換素子の光軸方向の長さを、入射光束の直径
よりも短くでき、さらに光束幅変換素子と偏光ビームス
プリッタの厚みを薄くすることができるので、偏光変換
素子の小型,軽量化,低コスト化が可能になる。In the above process, the light loss is a slight amount caused by absorption and scattering of the medium. As described above, by using the polarization conversion element of FIG. 2 according to the present invention to obtain linearly polarized light, it is possible to efficiently obtain linearly polarized light. Further, according to the configuration of the second embodiment, the length of the polarization conversion element in the optical axis direction can be made shorter than the diameter of the incident light beam, and the thickness of the light beam width conversion element and the polarization beam splitter can be reduced. Therefore, it is possible to reduce the size, weight and cost of the polarization conversion element.
【0038】以上、第1および第2の実施例の説明にお
いて、光束幅変換素子として、焦点距離の比が2:1の
2枚の平凸シリンドリカルレンズをケプラー型の配置に
した構成や、プリズムの屈折を利用して光束の幅を半分
にする構成のものも用いることができる。シリンドリカ
ルレンズは、片面または両面を球面、または非球面に加
工したものや、屈折率分布型のレンズ等も使用でき、そ
れらの組合せにより光束幅変換素子を構成しても良い。
光束反射素子として、アルミ表面鏡や直角プリズムの他
にも、銀等の金属または誘電体多層膜を蒸着した表面鏡
や、偏光ビームスプリッタ等も用いることができる。1
/2波長板としては、この他に、位相差板を2枚以上重
ねた構造のものや、複屈折性のある光学結晶、配向処理
を施した2枚のガラス基板で液晶を挟んだ構造の液晶セ
ル等も用いることができる。また、出射光の偏光度をさ
らに向上させるために、出射光の光路に偏光板を挿入し
ても良い。この場合、偏光板に入射する光は、あらかじ
め直線偏光化されているので、偏光板の光の吸収は少な
く、光利用効率の低下、熱の発生、並びに、それに伴う
性能の劣化は少ない。In the above description of the first and second embodiments, as the light beam width converting element, two plano-convex cylindrical lenses having a focal length ratio of 2: 1 are arranged in a Kepler-type arrangement, or a prism. It is also possible to use a structure in which the width of the light flux is halved by utilizing the refraction of. As the cylindrical lens, one having one surface or both surfaces processed into a spherical surface or an aspherical surface, a gradient index lens, or the like can be used, and the light flux width conversion element may be configured by a combination thereof.
As the light flux reflecting element, a surface mirror having a metal such as silver or a dielectric multilayer film deposited thereon, a polarization beam splitter, or the like can be used in addition to the aluminum surface mirror and the rectangular prism. 1
In addition to this, as the / 2 wavelength plate, a structure in which two or more retardation plates are stacked, an optical crystal having birefringence, or a structure in which a liquid crystal is sandwiched between two glass substrates that have been subjected to an alignment treatment A liquid crystal cell or the like can also be used. Further, in order to further improve the polarization degree of the emitted light, a polarizing plate may be inserted in the optical path of the emitted light. In this case, since the light incident on the polarizing plate is linearly polarized in advance, the light absorption by the polarizing plate is small, and the light utilization efficiency is reduced, heat is generated, and the performance is not deteriorated.
【0039】[0039]
【発明の効果】以上説明したように、本発明によれば、
光源から出射される不定偏光光を効率良く直線偏光光に
変換することが可能な偏光変換素子を得ることができ
た。As described above, according to the present invention,
A polarization conversion element capable of efficiently converting indefinite polarized light emitted from a light source into linearly polarized light can be obtained.
【0040】特に投射型液晶表示装置に用いる場合、照
明光の光束径が大きいため従来例で問題となった、偏光
ビームスプリッタの大きさも小型にすることができ、素
子全体の大きさも、従来例と本発明の第2の実施例とを
比較すると、例えば入射光束径80mmφの場合、光軸
方向の長さが62.5%、外形の堆積が42.0%、重
量は18.1%になり小型,軽量化が実現できた。ま
た、本発明では、偏光ビームスプリッタで分離した光束
を再び合成する必要がないため、入射角依存性のある液
晶表示素子や光学素子を用いても投射画像の画質が劣化
することはなく、投射レンズの口径食による問題も生じ
なかった。さらに、効率良く直線偏光光を得ることがで
きるので、装置の低消費電力化が可能であり、発熱によ
る悪影響等も避けられるという効果もあった。すなわ
ち、本発明によれば、投射型液晶表示装置において、偏
光板や液晶表示素子の劣化、投射画像の画質劣化、装置
の大型化、大幅な製造コストの上昇を伴わずに、投射画
像の高輝度化に有効な偏光変換素子を得ることができ
た。Particularly when used in a projection type liquid crystal display device, the size of the polarization beam splitter, which has been a problem in the conventional example due to the large luminous flux diameter of the illumination light, can be made small, and the size of the entire element is also reduced. Comparing with the second embodiment of the present invention, for example, when the incident light beam diameter is 80 mmφ, the length in the optical axis direction is 62.5%, the outer shape deposition is 42.0%, and the weight is 18.1%. Therefore, it was possible to realize smaller size and lighter weight. Further, in the present invention, since it is not necessary to combine the light beams separated by the polarization beam splitter again, even if a liquid crystal display element or an optical element having an incident angle dependency is used, the image quality of the projected image is not deteriorated, and the projection image is projected. There was no problem due to vignetting of the lens. Furthermore, since it is possible to efficiently obtain linearly polarized light, it is possible to reduce the power consumption of the device, and it is possible to avoid the adverse effect of heat generation. That is, according to the present invention, in the projection type liquid crystal display device, the projection image can be displayed at a high image quality without deterioration of the polarizing plate or the liquid crystal display element, deterioration of the image quality of the projection image, increase in size of the device, and significant increase in manufacturing cost. It was possible to obtain a polarization conversion element that is effective for increasing the brightness.
【0041】なお、本発明に従う偏光変換素子は、投射
型液晶表示装置のみならず、偏光光を使用する機器や装
置に対して有効である。The polarization conversion element according to the present invention is effective not only for projection type liquid crystal display devices but also for devices and devices that use polarized light.
【図面の簡単な説明】[Brief description of drawings]
【図1】本発明の第1の実施例を示す偏光変換素子の平
面図である。FIG. 1 is a plan view of a polarization conversion element showing a first embodiment of the present invention.
【図2】本発明の第2の実施例を示す偏光変換素子の平
面図である。FIG. 2 is a plan view of a polarization conversion element showing a second embodiment of the present invention.
1,21 光束幅変換素子 2,22 偏光ビームスプリッタ 3,23 光束反射素子 4,24 1/2波長板 5,6,25,26 シリンドリカルレンズ 7 偏光分離面 8 光束反射面 10 入射光 11,14,16 出射光 12 p偏光光 13 s偏光光 15 反射光 20 構成要素 1, 21 Light flux width conversion element 2, 22 Polarization beam splitter 3, 23 Light flux reflection element 4, 24 1/2 wavelength plate 5, 6, 25, 26 Cylindrical lens 7 Polarization separation surface 8 Light flux reflection surface 10 Incident light 11, 14 , 16 Emitted light 12 p-polarized light 13 s-polarized light 15 reflected light 20 components
Claims (1)
幅変換素子と、 前記光束幅変換素子からの出射光を互いに偏光方向が直
交するp偏光光とs偏光光の2つの直線偏光光に分離す
る偏光分離面を、前記光束幅変換素子の光束幅を縮小す
る方向と前記s偏光光の反射方向とが平行になるように
形成した偏光ビームスプリッタと、 前記偏光分離面と互いに平行な光束反射面を有し、前記
s偏光光の反射方向に前記偏光ビームスプリッタと隣接
して配置した光束反射素子と、 前記偏光ビームスプリッタで分離されたp偏光光とs偏
光光のどちらか一方の光路に配置した1/2波長板とを
構成要素とし、 前記構成要素を単独で、または2組以上を並列に配置し
て構成されることを特徴とする偏光変換素子。1. A light flux width conversion element for reducing the width of a light flux to half in one direction, and two linearly polarized light beams, p-polarized light and s-polarized light, whose polarization directions are orthogonal to each other. A polarization beam splitting surface for splitting light into light is formed so that a direction in which the light flux width of the light flux width conversion element is reduced and a reflection direction of the s-polarized light are parallel to each other; Light-reflecting element having a light-reflecting surface that is adjacent to the polarization beam splitter in the reflection direction of the s-polarized light, and one of p-polarized light and s-polarized light separated by the polarization beam splitter. And a half-wave plate arranged in the optical path of 1. as a constituent element, and the constituent element is configured alone or by arranging two or more sets in parallel.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3236715A JP2830534B2 (en) | 1991-09-18 | 1991-09-18 | Polarization conversion element |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3236715A JP2830534B2 (en) | 1991-09-18 | 1991-09-18 | Polarization conversion element |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH0572417A true JPH0572417A (en) | 1993-03-26 |
JP2830534B2 JP2830534B2 (en) | 1998-12-02 |
Family
ID=17004703
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP3236715A Expired - Lifetime JP2830534B2 (en) | 1991-09-18 | 1991-09-18 | Polarization conversion element |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP2830534B2 (en) |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1997034173A1 (en) * | 1996-03-12 | 1997-09-18 | Seiko Epson Corporation | Polarized light separator, method of manufacturing the same, and projection display |
EP0830626A2 (en) * | 1995-04-24 | 1998-03-25 | Polycom, Inc. | High efficiency homogeneous polarization converter |
US5764412A (en) * | 1994-10-15 | 1998-06-09 | Fujitsu Limited | Polarization separation/conversion device for polarized lighting apparatus and projection display unit |
EP0889351A1 (en) * | 1996-10-30 | 1999-01-07 | Seiko Epson Corporation | Projection display and illuminating optical system therefor |
US5986809A (en) * | 1997-06-06 | 1999-11-16 | Seiko Epson Corporation | Polarization conversion element, polarization illuminator, display using the same illuminator, and projection type display |
US6147802A (en) * | 1994-12-28 | 2000-11-14 | Seiko Epson Corporation | Polarization luminaire and projection display |
EP1031870A3 (en) * | 1999-02-23 | 2001-09-05 | Seiko Epson Corporation | Illumination system and projector |
USRE39951E1 (en) | 1996-06-25 | 2007-12-25 | Seiko Epson Corporation | Polarization conversion element, polarization illuminator, display using the same illuminator, and projector |
JP2009069809A (en) * | 2007-08-22 | 2009-04-02 | Epson Toyocom Corp | Polarization conversion element and method for manufacturing polarization conversion element |
US7965035B2 (en) | 2005-10-11 | 2011-06-21 | Seiko Epson Corporation | Light-emitting device, method for manufacturing light-emitting device, and image display apparatus |
US8279523B2 (en) | 2007-08-22 | 2012-10-02 | Seiko Epson Corporation | Polarization conversion element and method for manufacturing the same |
US10955107B1 (en) | 2017-08-09 | 2021-03-23 | Koito Manufacturing Co., Ltd. | Vehicle headlight |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH04310903A (en) * | 1991-04-09 | 1992-11-02 | Canon Inc | Plate like polarizing element, polarized light conversion unit equipped with same element, and image projection device equipped with same unit |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2580104B2 (en) | 1984-10-09 | 1997-02-12 | ソニー株式会社 | Projection type display device |
-
1991
- 1991-09-18 JP JP3236715A patent/JP2830534B2/en not_active Expired - Lifetime
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH04310903A (en) * | 1991-04-09 | 1992-11-02 | Canon Inc | Plate like polarizing element, polarized light conversion unit equipped with same element, and image projection device equipped with same unit |
Cited By (23)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5764412A (en) * | 1994-10-15 | 1998-06-09 | Fujitsu Limited | Polarization separation/conversion device for polarized lighting apparatus and projection display unit |
US6310723B1 (en) | 1994-12-28 | 2001-10-30 | Seiko Epson Corporation | Polarization luminaire and projection display |
EP1063555A3 (en) * | 1994-12-28 | 2002-03-13 | Seiko Epson Corporation | Polarization luminaire and projector using it |
US6445500B1 (en) | 1994-12-28 | 2002-09-03 | Seiko Epson Corporation | Polarization luminaire and projection display |
US6411438B1 (en) | 1994-12-28 | 2002-06-25 | Seiko Epson Corporation | Polarization luminaire and projection display |
US6344927B1 (en) | 1994-12-28 | 2002-02-05 | Seiko Epson Corporation | Polarization luminaire and projection display |
US6147802A (en) * | 1994-12-28 | 2000-11-14 | Seiko Epson Corporation | Polarization luminaire and projection display |
US6667834B2 (en) | 1994-12-28 | 2003-12-23 | Seiko Epson Corporation | Polarization luminaire and projection display |
US7119957B2 (en) | 1994-12-28 | 2006-10-10 | Seiko Epson Corporation | Polarization luminaire and projection display |
EP0830626A2 (en) * | 1995-04-24 | 1998-03-25 | Polycom, Inc. | High efficiency homogeneous polarization converter |
EP0830626A4 (en) * | 1995-04-24 | 1998-12-02 | Polycom Inc | High efficiency homogeneous polarization converter |
WO1997034173A1 (en) * | 1996-03-12 | 1997-09-18 | Seiko Epson Corporation | Polarized light separator, method of manufacturing the same, and projection display |
USRE39951E1 (en) | 1996-06-25 | 2007-12-25 | Seiko Epson Corporation | Polarization conversion element, polarization illuminator, display using the same illuminator, and projector |
EP0889351A4 (en) * | 1996-10-30 | 2002-04-17 | Seiko Epson Corp | Projection display and illuminating optical system therefor |
EP0889351A1 (en) * | 1996-10-30 | 1999-01-07 | Seiko Epson Corporation | Projection display and illuminating optical system therefor |
US5986809A (en) * | 1997-06-06 | 1999-11-16 | Seiko Epson Corporation | Polarization conversion element, polarization illuminator, display using the same illuminator, and projection type display |
US6154320A (en) * | 1997-06-06 | 2000-11-28 | Seiko Epson Corporation | Polarizing conversion device, polarizing illuminations device, and display apparatus and projector using the devices |
US6513953B1 (en) | 1999-02-23 | 2003-02-04 | Seiko Epson Corporation | Illumination system and projector |
EP1031870A3 (en) * | 1999-02-23 | 2001-09-05 | Seiko Epson Corporation | Illumination system and projector |
US7965035B2 (en) | 2005-10-11 | 2011-06-21 | Seiko Epson Corporation | Light-emitting device, method for manufacturing light-emitting device, and image display apparatus |
JP2009069809A (en) * | 2007-08-22 | 2009-04-02 | Epson Toyocom Corp | Polarization conversion element and method for manufacturing polarization conversion element |
US8279523B2 (en) | 2007-08-22 | 2012-10-02 | Seiko Epson Corporation | Polarization conversion element and method for manufacturing the same |
US10955107B1 (en) | 2017-08-09 | 2021-03-23 | Koito Manufacturing Co., Ltd. | Vehicle headlight |
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