Liquid crystal projection display system

• US 6,309,071 B1
• Filed: 08/04/1999
• Issued: 10/30/2001
• Est. Priority Date: 08/04/1999
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Florence, James M., Huang, Austin L.
• Primary Examiner(s): DOWLING, WILLIAM C
• Application Number:
  US09/366,943
• Time in Patent Office: 818 Days
• Field of Search: 353/8, 353/20, 353/31, 353/84, 349/9, 349/8, 348/742, 348/743
• US Class Current: 353/31
• CPC Class Codes: H04N 9/3111 for displaying the colours sequentially, e.g. by using sequentially activated light sources sequential projection in colour photography G03B33/08
• 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

Abstract

A projection display system comprises a light source that generates non-polarized light having at least two polarization states and having a first color component, a second color component, and a third color component. At least one color selection device selectively transmits at different times one of the second and third color components. The system has at least four polarized light modulators, two of the light modulators each generating a respective image associated with each respective polarization state of the first color component, and two of the light modulators each generating a respective image associated with a respective polarization state of one of the second and third color components transmitted by the color selection device. The system also has a projection lens for projecting the images from the polarized light modulators. Alternative projection display systems are disclosed, together with a method for projecting color images.

Claims

1. A projection display system comprising:

(a) a light source that generates generally non-polarized light having a first color component, a second color component, and a third color component;

(b) at least one color selection device that selectively transmits at different times one of said first and second color components, and said first and third color components;

(c) at least two pair of polarized light modulators, one of said pair of light modulators generating respective images associated with respective polarization states of said first color component, and the other of said pair of light modulators generating respective images associated with respective polarization states of one of said second and third color components in cooperation with said at least one color selection device; and

(d) a projection lens for projecting said images from said polarized light modulators.

2. The projection display system of claim 1 wherein a portion of one of said color components overlaps a portion of another of said color components.

3. The projection display system of claim 1 wherein each of said color components is free from overlapping another of said color components.

4. The projection display system of claim 1 wherein said color selection device is a color wheel.

5. The projection display system of claim 1 wherein said color selection device is an optical switch.

6. The projection display system of claim 1, further comprising a selective color component rotator, said color component rotator being located at at least one of (1) between said light source and said at least two pair of polarized light modulators and (2) between said at least two pair of polarized light modulators and said projection lens.

7. The projection display system of claim 1 wherein said color selection device transmits said second color component for a first time period, said color selection device transmits said third color component for a second time period, and said first time period is different than said second time period.

8. The projection display system of claim 1, further comprising drive electronics synchronized to said color selection device.

9. The projection display system of claim 8 wherein said drive electronics drives said two pair of polarized light modulators at different respective frame rates.

10. A projection display system comprising:

(a) a light source that generates non-polarized light having at least a first color component and a second color component;

(b) at least one color selection device that selectively transmits at different times said second color component and said at least one color selection device transmits said first color component;

(c) at least four polarized light modulators, two of said light modulators each generating a respective image associated with a respective polarization state of said first color component, and two of said light modulators each generating a respective image associated with a respective polarization state of said second color component; and

(d) a projection lens for projecting said images from said polarized light modulators.

11. The projection display device of claim 10 wherein said color selection device is a color wheel.

12. The projection display system of claim 10 wherein said color selection device is an optical switch.

13. The projection display device of claim 10, further comprising a selective color component rotator, said color component rotator being located at at least one of (1) between said light source and said at least two pair of polarized light modulators and (2) between said at least two pair of polarized light modulators and said projection lens.

14. A projection display system, comprising:

(a) a light source that generates non-polarized light having a plurality of color components;

(b) a color selection device that selectively transmits different ones of said plurality of color components at different times;

(c) a polarization separator having a first optical path for light based upon the combination of at least the color of the light and a first polarization state of the light and a second optical path for light based upon the combination of at least the color of the light and a second polarization state of the light, each of said optical paths producing respective images for each of said plurality of color components; and

(d) a projection lens for projecting said images.

15. The projection display system of claim 14 wherein said color selection device is a color wheel.

16. The projection display system of claim 14 wherein said color selection device is an optical switch.

17. The projection display device of claim 14 wherein each optical path further comprises a selective color component rotator, said color component rotator being located at at least one of (1) between said light source and said at least two pair of polarized light modulators and (2) between said at least two pair of polarized light modulators and said projection lens.

18. The projection display system of claim 14 wherein each optical path further comprises a plurality of polarized light modulators.

19. A method for projecting color images, comprising:

(a) generating light that has at least two polarization states and a first color component, a second color component, and a third color component;

(b) selectively transmitting at different times said second and third color components, and transmitting said first color component;

(c) generating a respective image associated with each respective polarization state of said first color component, and generating at different times a respective image associated with each respective polarization state of said second and third color components simultaneously with at least one of said respective image associated with each respective polarization state of said first color component; and

(d) projecting said images through a projection lens.

20. The method of claim 19 wherein light of a first polarization state is transmitted along a first optical path and light from a second polarization state is transmitted along a second optical path.

21. The method of claim 19, further comprising the step of selectively changing one color component from a first polarization state to a second polarization state while maintaining another color component in said first polarization state.

22. The method of claim 19 wherein a color wheel selectively transmits said second and third color components.

23. The method of claim 19 wherein an optical switch selectively transmits said second and third color components.