Electrostatically actuatable light modulating device

• US 5,062,689 A
• Filed: 08/21/1990
• Issued: 11/05/1991
• Est. Priority Date: 08/21/1990
• Status: Expired due to Fees

• Current Assignee: Dale R. Koehler
• Original Assignee: Dale R. Koehler
• Inventors: Koehler, Dale R.
• Primary Examiner(s): Arnold, Bruce Y.
• Assistant Examiner(s): Phan, James
• Application Number:
  US07/570,539
• Time in Patent Office: 441 Days
• Field of Search: 350/269, 350/384, 350/385, 350/96.13, 350/96.14, 350/266, 350/271, 350/272, 350/311, 350/319, 350/322
• US Class Current: 359/230
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 5/005 Diaphragms for cameras G03B9/02
• CPC Class Codes: G09F 9/372 the positions of the elements being controlled by the application of an electric field
• CPC Class Codes: H04N 9/3108 by using a single electronic spatial light modulator

Abstract

The electrostatically actuatable light modulator utilizes an opaque substrate plate patterned with an array of aperture cells, the cells comprised of physically positionable dielectric shutters and electrostatic actuators. With incorporation of a light source and a viewing screen, a projection display system is effected. Inclusion of a color filter array aligned with the aperture cells accomplishes a color display. The system is realized in terms of a silicon based manufacturing technology allowing fabrication of a high resolution capability in a physically small device which with the utilization of included magnification optics allows both large and small projection displays.

Claims

1. An electrostatically actuatable light modulating device comprising:

a substrate plate patterned with an array of light passing apertures; and

,

a co-located array of shuttering cells to spatially control light transmission through the aperture array, each of the cells comprising;

a mechanically positionable shutter means;

an electrostatic field actuator means to forcibly move the shutter means;

a position dependent mechanical restoring force means acting on said shutter means and in opposition to said electrostatic field actuator means; and

,

an electrical switch element means which is uniquely addressable within the array, to provide electrical energy to said electrostatic field actuator means.

2. The device according to claim 1 wherein the shutter means is a mechanically positionable opaque dielectric.

3. The device according to claim 1 wherein the shutter means is a slotted shutter physically aligned to a slotted aperture array.

4. The device according to claim 1 wherein the shutter means is a wedged Fabry-Perot interferometer.

5. The device according to claim 1 wherein the electrical switch element means is a diode.

6. The device according to claim 1 wherein the electrical switch element means is a transistor.

7. The device according to claim 1 wherein the electrostatic field actuator means is a charge-based drive circuit.

8. The device according to claim 1 wherein the electrostatic field actuator means is a voltage-based drive circuit and a storage capacitor.

9. The device according to claim 1 wherein the position-dependent restoring force means is a mechanical spring element.

10. The device according to claim 1 wherein the position-dependent restoring force means is an electrostatic force element.

11. The device specified in claim 1, in combination with a light source, an optical system for concentrating light onto the modulating device and a viewing screen for displaying spatial images transmitted by the modulating device.

12. The combination specified in claim 11, in combination with a tristimulus color filter positionally aligned to the light modulator to produce color images.

13. The combination specified in claim 12, in combination with a second optical system for projecting magnified color images.

14. The combination specified in claim 13, in combination with an infrared filter or mirror interposed between light source and modulator to reduce heating of the modulator array.

15. The combination specified in claim 11, in combination with a second optical system for projecting magnified images.

16. The combination specified in claim 15, in combination with an infrared filter or mirror interposed between light source and modulator to reduce heating of the modulator array.