Color microdisplays and methods of manufacturing same

• US 5,940,159 A
• Filed: 04/17/1998
• Issued: 08/17/1999
• Est. Priority Date: 10/13/1995
• Status: Expired due to Fees

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Alvelda, Phillip
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): NGO, HUYEN LE
• Application Number:
  US09/062,097
• Time in Patent Office: 487 Days
• Field of Search: 349/204, 349/201, 349/202, 349/108, 349/57, 349/95, 428/1
• US Class Current: 349/202
• CPC Class Codes: G02B 2027/0132 comprising binocular systems
• CPC Class Codes: G02B 2027/0154 with movable elements
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence
• CPC Class Codes: G02F 1/136 Liquid crystal cells structurally associated with a semi-conducting layer or substrate, e.g. cells forming part of an integrated circuit G02F1/135 takes precedence
• CPC Class Codes: G02F 1/136277 formed on a semiconductor substrate, e.g. of silicon
• CPC Class Codes: G02F 2201/305 diffraction grating
• CPC Class Codes: G02F 2203/34 Colour display without the use of colour mosaic filters

Abstract

A color microdisplay utilizes diffraction gratings to provide an array of high efficiency color pixels. The microdisplay includes a semiconductor substrate and source of light disposed adjacent thereto. A cover plate may be disposed above the substrate and has a layer of conductive material on a surface of the cover plate opposite the substrate. An optically active material, such as liquid crystal material, may be disposed between the substrate and the cover plate. An array of pixels are formed on the substrate. The pixel array includes an array of diffraction grating elements. Each element includes one or more diffraction gratings. The pitch of each diffraction grating can be a function of the angle of the incident light and the desired diffraction output spectrum. An optical system directs the diffracted light from each grating through the optically active material into viewing optics.

Claims

1. A method for manufacturing a color generation device comprising:

providing a semiconductor substrate; and

forming an array of pixels on the substrate, which comprises

a) forming a planar array of diffraction grating elements, such that each pixel diffracts color components of incident light into a single order having a specific direction; and

b) forming an array of driving and addressing circuitry on the substrate.

2. The method of claim 1 wherein each diffraction grating element comprises a triad of diffraction gratings.

3. The method of claim 2 wherein each diffraction grating acts as a color filter.

4. The method of claim 1 wherein each diffraction grating element comprises a single diffraction grating.

5. The method of claim 2 further comprising blazing each diffraction grating.

6. The method of claim 4 further comprising blazing each diffraction grating.

7. The method of claim 4 wherein each diffraction grating acts as a color filter.

8. The method of claim 1 wherein the incident light is provided by a light source.

9. The method of claim 1 wherein the pitch of each diffraction grating element is a function of the angle of the incident light.

10. A method for manufacturing a color generation device comprising:

providing a semiconductor substrate;

forming an array of pixels on the substrate, which comprises forming a planar array of diffraction grating elements each having a pitch which compensates for incident uncollimated light, such that each pixel diffracts color components of incident light into a specific direction.

11. The method of claim 10 wherein an array of driving and addressing circuitry is formed on the substrate.

12. The method of claim 10, wherein an incident light is provided by a light source.

13. The method of claim 10 wherein the source comprises at least one white light source, a pseudo-white light source or tri-band light source.

14. The method of claim 10 wherein the source of light comprises multiple narrow band light sources.

15. The method of claim 10 wherein each diffraction grating element comprises a triad of diffraction gratings.

16. The method of claim 15 further comprising blazing each diffraction grating.

17. The method of claim 15 wherein each diffraction grating acts as a color filter.

18. The method of claim 10 wherein each diffraction grating element comprises a single diffraction grating.

19. The method of claim 18 further comprising blazing each diffraction grating.

20. The method of claim 18 wherein each diffraction grating acts as a color filter.