Apparatus and method for additive/subtractive pixel arrangement in color mosaic displays

• US 4,886,343 A
• Filed: 06/20/1988
• Issued: 12/12/1989
• Est. Priority Date: 06/20/1988
• Status: Expired due to Term

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Johnson, Michael J.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Gallivan, Richard
• Application Number:
  US07/211,827
• Time in Patent Office: 540 Days
• Field of Search: 350/335, 350/339 F, 350/337, 350/349, 350/333, 340/765, 340/784, 340/805
• US Class Current: 349/78
• CPC Class Codes: G02F 1/13475 in which at least one liquid crystal cell or layer is doped with a pleochroic dye, e.g. GH-LC cell G02F1/13476 takes precedence

Abstract

A liquid crystal display unit is described in which a first panel of pixel elements is used to control red and green portions of a displayed image using an additive technique while a second panel, having pixels aligned with the first panel pixels, controls the blue portion of the image through subtractive techniques. The resulting display system can provide enhanced brightness, resolution and color characteristics. The display system makes use of the fact that the eye is less sensitive to blue radiation for several visual parameters. As a result of the decreased sensitivity, the second (blue) panel can operate with less stringent requirements.

Claims

1. A liquid crystal display system comprising:

first panel means for controlling transmission of red and green image components therethrough; and

second panel means for controlling transmission of blue image components therethrough, said second panel components being aligned with said red and green image components.

2. The liquid crystal display system of claim 1 wherein said first panel means controls said red and green image components by additive spatial proximity techniques and wherein said second panel means controls said blue image components by subtractive techniques.

3. The liquid crystal display system of claim 2 wherein image resolution is determined by said red and green image components.

4. The liquid crystal display system of claim 2 wherein said first panel includes a first plurality of controllable liquid crystal pixel units for controlling transmission of red color components therethrough and wherein said first panel includes a second plurality of controllable liquid crystal pixel units for controlling transmission of green color components therethrough.

5. The liquid crystal display unit of claim 4 wherein said second panel includes a third plurality of controllable liquid crystal pixel units, each of said third plurality of pixel units aligned with a plurality of first panel pixel units.

6. The liquid crystal display unit of claim 5 wherein brightness parameters of an image are controlled by said first panel pixel units.

7. The liquid crystal display unit of claim 6 wherein said first, second and third pluralities of pixel units are controlled using matrix addressing techniques.

8. The method of displaying an image, said method comprising the steps of:

controllably transmitting blue image components through a second panel in response to white light applied thereto; and

controllably transmitting red and green image components through a first panel, said second panel receiving light from said second panel.

9. The method of displaying an image of claim 8 wherein said first and said second panel include liquid crystal pixel units, a first plurality of pixel units of said first panel controlling transmission of red image components, a second plurality of pixel units of said first panel controlling transmission of red image components, the method further comprising the step of visually integrating light through proximate red pixel units and green pixel units.

10. The method of displaying an image of claim 9 further comprising the step of controlling transmission of light through pixel units of said first panel by address control networks.

11. The method of displaying an image of claim 10 wherein pixel units of said second panel are at least as large as pixel units of said first panel, said method further comprising the step of aligning said first and said second panel so radiation transmitted through a pixel unit of said second panel is transmitted through a plurality of pixel units of said first panel.

12. The method of displaying an image of claim 11 further comprising the step of controlling a brightness of said image by controlling an amount of radiation transmitted by said first panel.

13. The method of displaying an image of claim 12 further comprising the step of controlling image resolution by a structure of said red and green pixel units.

14. A liquid crystal display system for providing an image, said system comprising:

a source of optical radiation;

a second panel including first plurality of pixel units responsive to control signals for transmitting blue color components of said image along with red and green components of said optical radiation; and

a first panel having a second and third plurality of pixel units responsive to control signals, said second plurality of pixels transmitting blue radiation and red color image components in response to radiation transmitted through said second panel, said third plurality of pixel units transmitting blue radiation and green color image components in response to radiation transmitted through said second panel.

15. The liquid crystal display system of claim 14 wherein a brightness of said image is controlled by radiation through said first panel.

16. The liquid crystal display system of claim 14 wherein said second panel pixel units are at least as large as said first panel pixel units, a second panel pixel unit transmitting radiation transmitted by a plurality of pixel units of said first panel.

17. The liquid crystal display system of claim 16 wherein said second panel includes a dichroic material and a liquid crystal material along with a first plurality of control elements and said first panel includes a liquid crystal material, a mosaic of red/blue and green/blue filters and a first and second plurality of control elements.

18. The liquid crystal display system of claim 17 wherein colors of said image are obtained by combining radiation transmitted through a plurality of proximate first panel pixel units.

19. The liquid crystal display system of claim 18 wherein image resolution is determined by said first panel pixel units.

20. The liquid crystal display system of claim 19 wherein a white color is provided by activating neighboring green and red pixel units.