JPS6333736A - Transmission type screen - Google Patents
Transmission type screenInfo
- Publication number
- JPS6333736A JPS6333736A JP61178057A JP17805786A JPS6333736A JP S6333736 A JPS6333736 A JP S6333736A JP 61178057 A JP61178057 A JP 61178057A JP 17805786 A JP17805786 A JP 17805786A JP S6333736 A JPS6333736 A JP S6333736A
- Authority
- JP
- Japan
- Prior art keywords
- screen
- angle
- mirror
- light
- incidence
- 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
- 230000005540 biological transmission Effects 0.000 title claims abstract description 16
- 230000004907 flux Effects 0.000 abstract description 6
- 230000003287 optical effect Effects 0.000 description 9
- 230000000694 effects Effects 0.000 description 3
- 238000005452 bending Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Landscapes
- Overhead Projectors And Projection Screens (AREA)
- Transforming Electric Information Into Light Information (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は投写型画像表示装置に使用して有効な透過型ス
クリーンに関するものであり、特に投写光束を斜め方向
からスクリーン上に投写する場合に有効な透過型スクリ
ーンに関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a transmission screen that is effective for use in a projection type image display device, and is particularly effective when projecting a projection light beam onto the screen from an oblique direction. This relates to a transmissive screen.
従来の技術
大画面のテレビジョン画像を得るために、比較的小さな
映像管にテレビジョン画像を映出し、投写レンズよりス
クリーン上に拡大投写する方法が従来からよく知られて
いる。現在では、映像管、投写レンズ、透過型スクリー
ンの性能向上により、キャビネット内に光学系、回路系
を配置し、透過型のスクリーンの背後から画像を投写す
る方式の投写型テレビジョン装置の進歩が口ざましい。2. Description of the Related Art In order to obtain a large-screen television image, it has been well known that the television image is projected onto a relatively small picture tube and then enlarged and projected onto the screen using a projection lens. Nowadays, improvements in the performance of picture tubes, projection lenses, and transmissive screens have led to advancements in projection television equipment, which places the optical system and circuitry inside the cabinet and projects images from behind the transmissive screen. It's annoying.
さらに最近では、この方式の投写型テレビジョン装置の
奥行を非常に薄くすることを狙って、投写レンズから出
る光束を透過型スクリーンに対してかなり斜め方向から
入射させる方法が提案されている（例えば、特開昭５７
−１０９４８１号公報）。Furthermore, recently, with the aim of making the depth of this type of projection television device extremely thin, a method has been proposed in which the light flux emitted from the projection lens enters the transmissive screen from a considerably oblique direction (for example, , Japanese Patent Publication No. 57
-109481).
このような投写型テレビジョン装置の概略構成を第５図
に示す。キャビネットｌの上部前側に透過型のスクリー
ン２が配置され、上端に平面ミラー３が配置され、下部
にフェイスプレート４を上に向けて映像管５が配置され
、映像管５の上方に投写レンズ６が配置されている。映
像管５に映出される画像が投写レンズ６の結像作用と平
面ミラー３の反射作用によりスクリーン２上に拡大投写
されるが、投写レンズ６から出る光束はスクリーン２に
対してかなり斜め方向から入射するので、平面ミラー３
の奥行方向の長さが短くなり、キャビネット１の奥行を
非常に薄くすることが可能となる。FIG. 5 shows a schematic configuration of such a projection television apparatus. A transmission screen 2 is arranged at the front of the upper part of the cabinet l, a plane mirror 3 is arranged at the upper end, a picture tube 5 is arranged at the bottom with the face plate 4 facing upward, and a projection lens 6 is arranged above the picture tube 5. is located. The image projected on the picture tube 5 is enlarged and projected onto the screen 2 by the imaging action of the projection lens 6 and the reflection action of the plane mirror 3, but the light flux coming out of the projection lens 6 is from a direction quite oblique to the screen 2. Since it is incident, the plane mirror 3
The length in the depth direction is shortened, and the depth of the cabinet 1 can be made very thin.
スクリーン２は、第６図に示すように、透明平板の裏面
に断面が三角形のプリズム素子７を規則正しく配列した
ものである。プリズム素子７の第１面８に入射した光＊
９は、第１面８を屈折透過した後、第２面ｌＯで全反射
して前方向に折り曲げられる。このようにして、スクリ
ーン２に対してかなり斜め方向から光線が入射しても、
プリズム素子７の光線折り曲げ作用により、スクリーン
２の正面に位置する観察者に対して明るい投写画像を提
供することができる。As shown in FIG. 6, the screen 2 has prism elements 7 each having a triangular cross section arranged regularly on the back surface of a transparent flat plate. Light incident on the first surface 8 of the prism element 7 *
After the beam 9 is refracted and transmitted through the first surface 8, it is totally reflected at the second surface 10 and bent forward. In this way, even if the light rays are incident on the screen 2 from a considerably oblique direction,
Due to the beam bending effect of the prism element 7, a bright projected image can be provided to an observer located in front of the screen 2.
発明が解決しようとする問題点
第５図に示した構成の投写型テレビジョン装置に第６図
に示すスクリーン２を用いた場合、明るい室内では画像
のコントラストが著しく低下するという問題を生じる。Problems to be Solved by the Invention When the screen 2 shown in FIG. 6 is used in the projection television apparatus having the configuration shown in FIG. 5, a problem arises in that the contrast of the image is significantly reduced in a bright room.
この問題は次の様に説明できる。This problem can be explained as follows.
第７図に示す様にスクリーン２が外光により前方上方向
から照明されると、ある入射角を持つ光線１１はスクリ
ーン２内に入射した後、プリズム素子の第２面１０で全
反射し第１面８を通過してミラー３に入射する。ミラー
３を反射した光線は再びスクリーン２に入射し、プリズ
ム素子の第１面８を通過して第２面１０を全反射して投
写光束の出射角に近い角度でスクリーン２を出射する。As shown in FIG. 7, when the screen 2 is illuminated from above by external light, the light ray 11 having a certain angle of incidence enters the screen 2 and is totally reflected by the second surface 10 of the prism element. The light passes through one surface 8 and enters the mirror 3. The light beam reflected by the mirror 3 enters the screen 2 again, passes through the first surface 8 of the prism element, is totally reflected by the second surface 10, and exits the screen 2 at an angle close to the exit angle of the projected light beam.
このような光線１１が画像形成に必要な投写光束に混じ
って観察されるので、コントラストが著しく低下する。Since such light rays 11 are observed mixed with the projection light flux necessary for image formation, the contrast is significantly reduced.
本発明はかかる点に鑑みてなされたもので、投写光束に
対して斜めに配置することによりキャビネットが非常に
コンパクトとなる透過型スクリーンでありながら、明る
い室内で観察しても画像のコントラストの良好な透過型
スクリーンを提供することを目的としている。The present invention was made in view of these points, and although it is a transmissive screen that allows the cabinet to be extremely compact by arranging it diagonally with respect to the projection light beam, it also provides good image contrast even when observed in a bright room. The purpose is to provide a transparent screen.
問題点を解決するための手段
上記問題点を解決するため、本発明の透過型スクリーン
は、透光性板の入射側面に断面が三角形状のプリズム素
子が配列され、投写光束がミラーを介して斜め方向から
入射し、前記プリズム素子の第１面で屈折透過し、第２
面で前方向に全反射した後、出射側面で屈折透過する透
過型スクリーンであって、ミラーを垂直に入出射する光
線の前記プリズム素子の第２面への入射角が全反射の臨
界角より小さくなるようにしたものである。Means for Solving the Problems In order to solve the above-mentioned problems, the transmission screen of the present invention has prism elements having a triangular cross section arranged on the incident side of a light-transmitting plate, so that the projected light beam is transmitted through a mirror. It is incident from an oblique direction, is refracted and transmitted by the first surface of the prism element, and the second
The screen is a transmissive screen that is totally reflected forward at a surface and then refracted and transmitted at an output side surface, and the incident angle of the ray entering and exiting the mirror perpendicularly to the second surface of the prism element is less than the critical angle for total reflection. It was made to be smaller.
作用
上記構成によれば、出射側面よりスクリーンに入射し、
プリズム素子の第２面で全反射し、ミラーで反射して再
びスクリーンに入射し、投写光束に近い角度で出射しよ
うとする外光は、プリズム素子の第２面への入射角がミ
ラーへの往路或いは復路いずれか一方で必ず全反射の臨
界より小さく゛ なり、プリズム素子の第２面を屈折透
過するので、投写光束に近い角度で出射する外光はなく
なる。Effect According to the above configuration, the light enters the screen from the exit side,
External light that is totally reflected on the second surface of the prism element, reflected on the mirror, enters the screen again, and exits at an angle close to the projected light flux is determined by the fact that the angle of incidence on the second surface of the prism element is Either the outgoing or returning path is always smaller than the critical value of total reflection and is refracted and transmitted through the second surface of the prism element, so that no external light exits at an angle close to the projected light beam.
従って、明るい室内で観察しても画像のコントラストの
良好な透過型スクリーンを提供できる。Therefore, it is possible to provide a transmission screen with good image contrast even when observed in a bright room.
実施例
本発明による透過型スクリーンの一実施例について添付
図面を参照しながら説明する。Embodiment An embodiment of a transmission screen according to the present invention will be described with reference to the accompanying drawings.
第１図は本発明の一実施例における透過型スクリーンの
中心部における要部断面図を示したもので、１２は透光
性板、１３はプリズム素子である！光性板１２の入射側
面には断面が三角形状のプリズム素子１３が規則正しく
配列され、プリズム素子１３は屈折面としての第１面１
４と全反射面としての第２面１５とで構成されている。FIG. 1 shows a sectional view of essential parts at the center of a transmission screen according to an embodiment of the present invention, where 12 is a light-transmitting plate and 13 is a prism element! Prism elements 13 having a triangular cross section are regularly arranged on the incident side of the optical plate 12, and the prism elements 13 have a first surface 1 as a refractive surface.
4 and a second surface 15 as a total reflection surface.
出射側面は投写光束が屈折透過する部分に屈折面として
の第３面１６を有している。The exit side surface has a third surface 16 as a refracting surface in a portion where the projected light beam is refracted and transmitted.
透光性板の屈折率は約１．４９２ 、プリズム素子１３
の頂角は約４５°、中心軸１７に対するプリズム素子１
３の第１面１４の傾斜角は約２００、出射側面の第３面
１６の傾斜角は約６０°、プリズム素子１３のピンチは
０．５鰭、中心軸１７に対するミラー３の傾斜角は約１
７．５ ＠である。The refractive index of the transparent plate is approximately 1.492, and the prism element 13
The apex angle of the prism element 1 with respect to the central axis 17 is approximately 45°.
The angle of inclination of the first surface 14 of the mirror 3 is about 200 degrees, the angle of inclination of the third surface 16 of the exit side is about 60 degrees, the pinch of the prism element 13 is 0.5 degrees, and the angle of inclination of the mirror 3 with respect to the central axis 17 is about 60 degrees. 1
7.5 @.
本発明の作用を以下に説明する。The operation of the present invention will be explained below.
第」図に示すように、透過型スクリーンの入射側面に入
射した投写光束は、プリズム素子の第１面１４で屈折透
過し第２面１５で全反射し、出射側面の第３面１６の部
分を屈折透過した後スクリーンにほぼ垂直に出射する。As shown in Figure 1, the projected light flux that has entered the entrance side of the transmission screen is refracted and transmitted through the first surface 14 of the prism element, is totally reflected at the second surface 15, and is reflected at the third surface 16 of the exit side. After being refracted and transmitted, it is emitted almost perpendicularly to the screen.
第７図に示す従来のスクリーンの場合に、出射側面から
スクリーン２に入射しミラー３で反射されて再びスクリ
ーン２に入射する光線の代表例を第２図に示す。第２図
において一点鎖線１８は、ミラー３に垂直に入出射する
、つまりミラーへの入射光路と反射光路が同じであるよ
うな光線を表す。In the case of the conventional screen shown in FIG. 7, FIG. 2 shows a typical example of a light ray that enters the screen 2 from the exit side, is reflected by the mirror 3, and then enters the screen 2 again. In FIG. 2, a dashed line 18 represents a light ray that enters and exits the mirror 3 perpendicularly, that is, the optical path of incidence on the mirror and the optical path of reflection are the same.
破ｖＡ１９はスクリーンの最上部に一点鎖線の光線１８
より垂直に近い角度で入射し、ミラー３で反射した後ス
クリーンの最下部から一点鎖線の光線１８より大きい角
度で出射する光線を表す。スクリーンのどの部分に入射
する外光もこの光線より小さい角度で入射すると、ミラ
ー３で反射された後スクリーンには戻らずスクリーン下
部のキャビネット１或いは投写レンズ６の方向に進む。Break vA19 is the dashed line ray 18 at the top of the screen.
It represents a ray that enters at an angle closer to perpendicular, is reflected by mirror 3, and then exits from the bottom of the screen at an angle larger than the ray 18 indicated by the dashed-dotted line. If external light enters any part of the screen at an angle smaller than this ray, it will not return to the screen after being reflected by the mirror 3, but will proceed toward the cabinet 1 or the projection lens 6 below the screen.
破線１９はまた、前途の光路を全く逆に進みスクリーン
の最下部に一点ｕｉ線の光線１８より大きい角度で入射
し、ミラー３で反射した後スクリーンの最上部から一点
鎖線の光線１８より小さい角度で出射する光線も表す。The dashed line 19 also travels in the opposite direction in the forward optical path and enters the bottom of the screen at an angle larger than the ray 18 of the one-point ui line, and after being reflected by the mirror 3, it enters the bottom of the screen at an angle smaller than the ray 18 of the one-dot chain line from the top of the screen. It also represents the rays emitted by .
スクリーンのどの部分に入射する外光もこの光線より大
きい角度で入射すると、ミラー３で反射された後スクリ
ーン上部のキャビネット１の内壁に入射するか或いはミ
ラー３！こ入射せず直接キャビネット１の内壁に入射す
る。If external light is incident on any part of the screen at an angle greater than this ray, it will be reflected by the mirror 3 and then incident on the inner wall of the cabinet 1 above the screen, or the mirror 3! The light does not enter directly into the inner wall of the cabinet 1.
以上より、ミラー３で反射してスクリーン２に戻る光線
の入射角度は、スクリーンの最上部に入射する破線の光
線１９の入射角度からスクリーンの最下部で出射する破
線の光線１９の出射角度の範囲内であり、この範囲外の
入射角度を持つ光線はスクリーンのどの部分に入射して
もスクリーン２に戻らないことが分かる。From the above, the incident angle of the light ray reflected by the mirror 3 and returning to the screen 2 is the range from the incident angle of the light ray 19 indicated by the broken line that enters at the top of the screen to the exit angle of the light ray 19 indicated by the broken line that exits at the bottom of the screen. It can be seen that light rays having an incident angle outside this range will not return to the screen 2 even if they are incident on any part of the screen.
またミラー３で反射してスクリーン２に戻る光線のスク
リーン２への入射角或いは出射角のいずれかは必ず一点
鎖線の光′！ｆｌＡ１８の入射角に等しいか或いは大き
いことも分かる。スクリーン２への入射角が大きくなる
と、プリズム素子の第２面１５への入射角は小さくなる
ので、ミラー３で反射してスクリーン２に戻る光線の第
２面への入射角は必ず一点鎖線の光線１８の入射角に等
しいか或いは小さいことになる。Also, either the incident angle or the exit angle of the ray of light reflected by the mirror 3 and returned to the screen 2 on the screen 2 is always indicated by the dashed-dotted line '! It can also be seen that the angle of incidence is equal to or larger than the angle of incidence of flA18. As the angle of incidence on the screen 2 becomes larger, the angle of incidence on the second surface 15 of the prism element becomes smaller. Therefore, the angle of incidence on the second surface of the light beam reflected by the mirror 3 and returned to the screen 2 is always the same as the one-dot chain line. It will be equal to or smaller than the angle of incidence of the light ray 18.
ところで本−実施例においては、ミラー３に垂直に入出
射する光線のプリズム素子の第２面１５への入射角が全
反射の臨界角よりに小さくなるようなスクリーン構造と
しているので、ミラー３で反射してスクリーンに戻る総
ての光線に対して、スクリーンへ入射する時或いはミラ
ー３で反射してスクリーンへ再入射する時のいずれかの
時にプリズム素子の第２面１５への入射角が全反射の臨
界より小さくなる。従って本−実施例においては第２図
に示すような光路を辿ってスクリーンを出射し、著しく
画像のコントラストを低下させる光線はなくなる。By the way, in this embodiment, the screen structure is such that the angle of incidence of the light beam perpendicularly entering and exiting the mirror 3 on the second surface 15 of the prism element is smaller than the critical angle of total reflection. For all the light rays that are reflected and return to the screen, the angle of incidence on the second surface 15 of the prism element is the same either when the light rays are incident on the screen or when they are reflected by the mirror 3 and re-enter the screen. It becomes smaller than the criticality of reflection. Therefore, in this embodiment, there is no light ray that exits the screen following the optical path shown in FIG. 2 and significantly reduces the contrast of the image.
第３図に示すように、投写光束の出射角に近い角度でス
クリーンへ入射する外光は、第２面への入射角が臨界角
より小さくとはならず全反射するが、ミラー３で反射さ
れて再びスクリーンへ入射した際には第２面への入射角
は臨界より小さくなり、この面を屈折透過し、一つ下の
プリズム素子へ入射した後スクリーン前方へ出射するが
、その大部分は同図に示すように、下方向に強く屈折す
る為、スクリーン正面の観察方向には出射せず、画像の
コントラストを著しく低下させることはない。As shown in Figure 3, external light that enters the screen at an angle close to the exit angle of the projected light beam is totally reflected as the angle of incidence on the second surface is not smaller than the critical angle, but it is reflected by mirror 3. When it enters the screen again, the angle of incidence on the second surface becomes smaller than the critical value, it is refracted and transmitted through this surface, enters the prism element one below, and then exits to the front of the screen, but most of it As shown in the figure, since the light is strongly refracted downward, it does not go out in the viewing direction in front of the screen, and the contrast of the image does not deteriorate significantly.
第４図に示すように、更に大きな角度でスクリーンへ入
射する外光は、第２図への入射角が臨界角より小さくな
り、第２面１５を屈折透過しスクリーンへは戻ってこす
、画像のコントラストを著しく低下させることはない。As shown in FIG. 4, external light that enters the screen at an even larger angle becomes smaller than the critical angle, is refracted and transmitted through the second surface 15, and returns to the screen. The contrast will not be significantly reduced.
映像管からの光線の入射角は第５図から理解されるよう
にスクリーンの上部及び下部では中心部での値から僅か
に変わるので、中心軸１７に対するプリズム素子１３の
第１面１４の傾斜角を変える等すると良好な画像が得ら
れる。As can be seen from FIG. 5, the angle of incidence of the light ray from the picture tube changes slightly at the top and bottom of the screen from the value at the center, so the angle of inclination of the first surface 14 of the prism element 13 with respect to the central axis 17 is A good image can be obtained by changing the .
発明の効果
以上述べたごとく本発明によれば、投写光束に対して斜
めに配置することによりキャビネットが非常にコンパク
トとなる透過型スクリーンでありながら、ミラーに垂直
に入出射する光線のブリズム素子の第２面への入射角が
全反射の臨界角より小さくなるようにスクリーンの厚さ
、プリズム素子の構造等を選択して、画像のコントラス
トを著しく低下させる外光はスクリーンへの入射時或い
はミラー反射後の再入射時のいずれかの時にプリズム素
子の第２面への入射角が全反射の臨界角より小さくなり
、観察方向に出射しないので、コントラストの良好な画
像が得られるという効果がある。Effects of the Invention As described above, according to the present invention, although it is a transmissive screen in which the cabinet can be made very compact by arranging it diagonally with respect to the projected light beam, the brism element of the light beam entering and exiting the mirror perpendicularly The thickness of the screen, the structure of the prism element, etc. are selected so that the angle of incidence on the second surface is smaller than the critical angle of total internal reflection, and external light that significantly reduces the contrast of the image is removed when it is incident on the screen or on the mirror. At some point during re-incidence after reflection, the angle of incidence on the second surface of the prism element becomes smaller than the critical angle for total reflection, and the light does not emerge in the observation direction, resulting in an image with good contrast being obtained. .
閲
第１改は本発明の一実施例における透過型スクリーンの
構成を示す要部断面図、第２図は従来の透過型スクリー
ンで問題となっている光線の代表的光路を説明する断面
図、第３図及び第４図は第１図の透過型スクリーンにお
ける前方よりスクリーンに入射する光線の光路を説明す
る断面図、第５図は投写型テレビジョン装置の構成を示
す断面図、第６図は第５図に示した投写型テレビジョン
装置に用いる従来の透過型スクリーンの構成を示す断面
図、第７図は第６図に示した従来の透過型スクリーンで
画像のコントラストを著しく低下させる光線の光路を説
明するための要部断面図である。
１２・・・・・・透光性板、１３・・・・・・プリズム
素子、１４・・・・・・プリズム素子の第１面、１５・
・・・・・プリズム素子の第２面、１６・・・・・・出
射側面の第３面。
代理人の氏名 弁理士 中尾敏男 はか１名第１０
第 ２ 図
嘉３図
第４図
第５図
第６図
第７図The first revision is a sectional view of a main part showing the configuration of a transmission screen in an embodiment of the present invention, and FIG. 2 is a sectional view illustrating a typical optical path of a light ray, which is a problem in a conventional transmission screen. 3 and 4 are cross-sectional views illustrating the optical path of light rays entering the screen from the front in the transmission screen of FIG. 1, FIG. 5 is a cross-sectional view showing the configuration of the projection television apparatus, and FIG. 5 is a sectional view showing the configuration of a conventional transmission screen used in the projection television apparatus shown in FIG. 5, and FIG. 7 is a sectional view showing the structure of the conventional transmission screen shown in FIG. FIG. 2 is a cross-sectional view of a main part for explaining an optical path of FIG. 12... Translucent plate, 13... Prism element, 14... First surface of prism element, 15.
...Second surface of the prism element, 16...Third surface of the exit side. Name of agent Patent attorney Toshio Nakao 1 person No. 10 No. 2 No. 3 No. 4 No. 5 No. 6 No. 7
Claims (1)
配列され、投写光束がミラーを介して斜め方向から入射
し、前記プリズム素子の第１面で屈折透過し、第２面で
前方向に全反射した後、出射側面で屈折透過する透過型
スクリーンであって、前記ミラーに垂直に入出射しよう
とする光線の前記第２面への入射角が全反射の臨界角よ
り小さくなるようにした透過型スクリーン。Prism elements with a triangular cross section are arranged on the incident side of the light-transmitting plate, and the projected light beam enters from an oblique direction via a mirror, is refracted and transmitted by the first surface of the prism element, and is reflected in the forward direction by the second surface. A transmission screen that undergoes total reflection and refraction and transmission at the exit side surface, the screen being such that the angle of incidence of the light beam that is about to enter and exit the mirror perpendicularly to the second surface is smaller than the critical angle for total reflection. transparent screen.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61178057A JPS6333736A (en) | 1986-07-29 | 1986-07-29 | Transmission type screen |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61178057A JPS6333736A (en) | 1986-07-29 | 1986-07-29 | Transmission type screen |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6333736A true JPS6333736A (en) | 1988-02-13 |
Family
ID=16041851
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61178057A Pending JPS6333736A (en) | 1986-07-29 | 1986-07-29 | Transmission type screen |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6333736A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2864853A1 (en) * | 2004-01-07 | 2005-07-08 | Thomson Licensing Sa | OPTICAL PLATE AND PROJECTION DISPLAY DEVICE USING SUCH PLATE |
-
1986
- 1986-07-29 JP JP61178057A patent/JPS6333736A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2864853A1 (en) * | 2004-01-07 | 2005-07-08 | Thomson Licensing Sa | OPTICAL PLATE AND PROJECTION DISPLAY DEVICE USING SUCH PLATE |
| WO2005066711A1 (en) * | 2004-01-07 | 2005-07-21 | Thomson Licensing | Overhead projection screen |
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