Combined color and monochrome display

• US 5,278,681 A
• Filed: 05/10/1993
• Issued: 01/11/1994
• Est. Priority Date: 09/02/1992
• Status: Expired due to Fees

• Current Assignee: AT&T, Inc.
• Original Assignee: AT&T, Inc.
• Inventors: Gitlin, Richard D., Ribera, John F., Woodworth, Clark, Kollarits, Richard V.
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): MAI, HUY KIM
• Application Number:
  US08/059,867
• Time in Patent Office: 246 Days
• Field of Search: 359/45, 359/48, 359/49, 359/69, 358/31, 358/85, 358/23, 358/25, 358/17, 358/92
• US Class Current: 349/61
• CPC Class Codes: G02F 1/133622 Colour sequential illumination
• CPC Class Codes: H04N 9/3108 by using a single electronic spatial light modulator
• CPC Class Codes: H04N 9/3155 for controlling the light source light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406
• CPC Class Codes: H04N 9/3164 using multiple light sources

Abstract

The advantages of both a color display and a high-resolution monochrome display are realized in a single display system by eliminating color filters from the display screen of the display system and illuminating the display screen with either colored light or white light to provide color or high-resolution monochrome capability, respectively. Simultaneous color and high-resolution monochrome capability is realized by illuminating predetermined portions of the display screen with only colored light while illuminating different portions of the display screen with only white light.

Claims

1. A display system configured to selectively display data to a viewer as at least one of color data at a first resolution and monochrome data at a second, higher resolution, the system comprising:

diffusing means having a surface for diffusing light impinging thereon;

means for illuminating the diffusing surface of the diffusing means with light comprising a plurality of discrete colors;

a white light source for illuminating the diffusing surface of the diffusing means with white light; and

means interposed between the diffusing means and the illuminating means for modulating the intensity of the light from the illuminating means and the white light source before the light impinges on the diffuse surface, so as to display on the diffusing means color data at the first resolution and monochrome data at the second resolution.

2. The apparatus as defined in claim 1 wherein the illuminating means comprises controllably switched light sources for illuminating the diffusing surface of the diffusing means with a plurality of discrete colors in a time-multiplexed sequence.

3. The apparatus as defined in claim 1 wherein the modulating means comprises a plurality of monochrome liquid crystal cells arranged in an array of n rows and m columns, each cell of the array selectively rotating the polarization of light passing therethrough to vary the intensity of the light.

4. The apparatus as defined in claim 3 wherein the illuminating means comprises a dot projector means for projecting an array of red, blue, and green color dots onto the diffusing surface of the diffusing means, each color dot passing through a different predetermined one of the monochrome liquid crystal cells.

5. The apparatus as defined in claim 1 further comprising means for selectively energizing one of the white light source and the illuminating means.

6. The apparatus as defined in claim 1 further comprising means for selectively blocking light output from the white light source and the illuminating means such that a first portion of the diffusing means is illuminated only by light from the white light projector means and a mutually exclusive second portion of the diffusing means is illuminated only by light from the illuminating means.

7. The apparatus as defined in claim 6 wherein the blocking means comprises:

a first array comprising a plurality of liquid crystal cells, the first array being imaged on the means for modulating by the white light source; and

a second array comprising a plurality of liquid crystal cells, the second array being imaged on the means for modulating by the illuminating means.

8. A method for displaying first predetermined data to a viewer as color data at a first resolution and simultaneously displaying second predetermined data as monochrome data at a second, higher resolution, the method comprising the steps of:

illuminating a first portion of a diffuse surface of a diffusing means with light comprising a plurality of discrete colors;

illuminating a second portion of the diffuse surface with white light; and

modulating the intensity of the white light and the light comprising a plurality of discrete colors with a modulating means before the white light and the light comprising a plurality of discrete colors impinges on the diffuse surface, so as to display on the diffusing means color data at the first resolution and monochrome data at the second resolution.

9. The method as defined in claim 8 wherein the step of illuminating the first portion comprises transmitting the plurality of discrete colors in a time-multiplexed sequence.

10. The method as defined in claim 8 wherein the modulating means comprises a plurality of monochrome liquid crystal cells arranged in an array of n rows and m columns, each cell of the array selectively rotating the polarization of light passing therethrough to vary the intensity of the light.

11. The method as defined in claim 10 wherein the step of illuminating the second portion comprises outputting an array of red, blue, and green color dots onto the second portion of the diffusing means, each color dot passing through a different one of the monochrome liquid crystal cells.

12. A display system configured to selectively display data to a viewer as at least one of color data at a first resolution and monochrome data at a second, higher resolution, the system comprising:

diffusing means having a surface for diffusing light impinging thereon;

means for illuminating the diffusing surface of the diffusing means with light comprising a plurality of discrete colors;

a white light source for illuminating the diffusing surface of the diffusing means with white light;

means interposed between the diffusing means and the illuminating means for modulating the intensity of the light from the illuminating means and the white light source before the light impinges on the diffuse surface, so as to display on the diffusing means color data at the first resolution and monochrome data at the second resolution, the modulating means comprising a plurality of monochrome liquid crystal cells arranged in an array of n rows and m columns, each cell of the array selectively rotating the polarization of light passing therethrough to vary the intensity of the light; and

means for selectively blocking light output from the white light source and the illuminating means such that a first portion of the diffusing means is illuminated only by light from the white light source and a mutually exclusive second portion of the diffusing means is illuminated only by light from the illuminating means.

13. The apparatus as defined in claim 12 wherein the illuminating means comprises a dot projector means for projecting an array of red, blue, and green color dots onto the diffusing surface of the diffusing means, each color dot passing through a different predetermined one of the monochrome liquid crystal cells.

14. The apparatus as defined in claim 12 wherein the illuminating means comprises controllably switched light sources for illuminating the diffusing surface of the diffusing means with a plurality of discrete colors in a time-multiplexed sequence.

15. The apparatus as defined in claim 12 wherein the blocking means comprises:

a second array comprising a plurality of liquid crystal cells, the second array being imaged on the monochrome liquid crystal array by the white light source; and

a third array comprising a plurality of liquid crystal cells, the third array being imaged on the monochrome liquid crystal array by the illuminating means.