Giant liquid crystal display means

• US 5,005,950 A
• Filed: 06/15/1989
• Issued: 04/09/1991
• Est. Priority Date: 06/28/1988
• Status: Expired due to Fees

• Current Assignee: Etat Francais, Represente Par Le Ministere Des Postes, Des Telecommunications Et De L'Espace
• Original Assignee: Etat Francais Represente Par Le Ministere Des Postes
• Inventors: Morin, Francois
• Primary Examiner(s): Miller, Stanley D.
• Assistant Examiner(s): Mai, Huy K.
• Application Number:
  US07/366,587
• Time in Patent Office: 663 Days
• Field of Search: 350/333, 350/331 R, 350/334, 350/338, 350/339 F, 358/60, 358/61, 340/784
• US Class Current: 349/5
• CPC Class Codes: G09F 19/18 involving the use of optical projection means, e.g. projection of images on clouds projection apparatus per se G03B
• CPC Class Codes: G09F 9/35 being liquid crystals G09F9/302 takes precedence; liquid crystal materials C09K19/00; liquid crystal panels comprising a number of electrodes in a single cell per se G02F1/13
• CPC Class Codes: H04N 9/3147 Multi-projection systems displays in general H04N9/12; video walls G06F3/1446, G09G2300/026

Abstract

Giant liquid crystal display means. The means comprises projection modules (MP) associated with mirrors (M1, M2) and a large screen (E). The screen carries colored filters (R, G, B) and the liquid crystal displays are monochromatic. Application to the projection of large television or pictures.

Claims

1. A giant display device comprising a large translucent screen having a front face directed toward an observer and a rear face covered by a mosaic of colored filters organized in triads of primary colors, a liquid crystal display device having a mosaic of pixels, a plurality of optical projection modules comprising a white light source and optical means for projecting an image of said mosaic of pixels of said liquid crystal display device onto said mosaic of colored filters on said rear face of said screen, each pixel of said mosaic of pixels of said liquid crystal display device being optically projected by said optical projection modules on one filter of said mosaic of colored filters.

2. A giant display device according to claim 1, wherein said plurality of optical projection modules are juxtaposed in rows and columns, the images projected by said modules juxtaposed in rows and columns for forming a single image on said screen.

3. A giant display device according to claim 1, wherein said screen is constituted by a transparent support having a matte rear face.

4. A giant display device according to claim 1, wherein said screen comprises on its rear face a black matrix for separating said colored filters.

5. A giant display device according to claim 1, wherein said liquid crystal display device is of the active matrix type.

6. A giant display device according to claim 5, wherein said active matrix display is of the thin film transistor type.

7. A giant display device according to claim 5, wherein said colored filters are distributed in triangular form (R, G, B) and said liquid crystal display device comprises pixels also organized in triangular form.

8. A giant display device according to claim 1, wherein each optical projection module comprises, in front of said light source successively, a condenser, a double Fresnel lens, a first polarizer, a projection lens with an object focal plane in which is placed said liquid crystal display device, a first reflecting mirror, a second reflecting mirror, and a second polarizer, said screen being placed in the image plane of the projection lens.

9. A giant display device according to claim 8, wherein said second polarizer is placed against said rear face of said screen.

10. A giant display device according to claim 1, comprising further means for checking the light intensity projected by each projection module and means for controlling on return said intensity at an appropriate value.