Total internal reflection spatial light modulation apparatus and method of fabrication thereof

• US 5,455,709 A
• Filed: 03/23/1993
• Issued: 10/03/1995
• Est. Priority Date: 03/23/1993
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Martin Marietta Corporation
• Inventors: Dula, Thomas C. III, Bailey, Alex E., Caldwell, Paul J.
• Primary Examiner(s): Nguyen, Viet Q.
• Application Number:
  US08/048,331
• Time in Patent Office: 924 Days
• Field of Search: 359/240, 359/245, 359/247, 359/246, 359/316, 359/318, 359/263
• US Class Current: 359/245
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 26/0858 the reflecting means being moved or deformed by piezoelectric means
• CPC Class Codes: G02F 1/05 with ferro-electric properties G02F1/035, G02F1/055 take precedence
• CPC Class Codes: G02F 1/195 by using frustrated reflection digital reflection using controlled total internal reflection G02F1/315
• CPC Class Codes: G09F 9/372 the positions of the elements being controlled by the application of an electric field

Abstract

Total internal light spatial light modulation apparatus includes a light source for projecting infrared light; a prism for reflecting the projected light from an internal surface therein; and an array of pixel posts made of electrostrictive material and positioned proximate a back face of the internal surface for selectively eliminating pixel areas of reflection of the projected light to form an image thereby. A multiplexer is provided to select a set of pixel posts to be electrically charged which corresponds with the image, and electrical contacts are formed on each pixel post no permit electrical charging of each selected pixel post. Method of fabricating the pixel post array, wherein each row of the pixel post array is formed as a monolithic structure, includes the steps of providing a slab of alternate layers of ferroelectric and electrically-conductive material; vapor-depositing electrical contacts on the slabs in electrical communication with the layers of electrically-conductive material at locations corresponding to the pixel posts to be fabricated; securing the slabs together in a front-to-back relationship with divider plates positioned therebetween; and cross-cutting a number of grooves through the slabs to define the pixel posts of each row.

Claims

1. A spatial light modulation apparatus for generating an image utilizing light projected from a light source, the apparatus comprising:

a prism having an input end for receiving the projected light, a boundary surface angled for total internal reflection of the projected light received through the input end, and an output end for emitting the projected light reflected from the boundary surface; and

means for eliminating total internal reflection of the projected light at selected pixel areas of the boundary surface to form the image thereby, the eliminating means including

a pixel post array including a plurality of pixel posts arranged into rows, each row of pixel posts formed as a monolithic structure from a respective slab of ferroelectric material each pixel post having a base end and an opposite free end each pixel post being configured to expand upon being energized to move the free end toward the boundary surface of the prism to eliminate total internal reflection of the projected light at the pixel area corresponding to the free end of the pixel post,

means for selecting from the pixel post array a set of pixel posts to be energized, the set of pixel posts corresponding with the image, and

means for energizing each pixel post of the selected set of pixel posts.

2. The apparatus of claim 1, wherein each pixel post of the pixel post array includes alternate adjacent transverse layers of ferroelectric material and electrically-conductive material;

and further wherein the energizing means communicates electrically with the layers of electrically-conductive material to provide an electrical charge to each adjacent layer of ferroelectric material.

3. The apparatus of claim 1, wherein divider plates are affixed to and positioned between the respective slabs to provide a spaced-apart relationship between the rows of pixel posts.

4. The apparatus of claim 1, wherein the eliminating means further includes a light-absorbing layer formed on the free end of each pixel post for absorbing the protected light at the pixel area corresponding to the free end when the free end is moved to a position proximate the boundary surface of the prism by selective expansion of the pixel post.

11. The apparatus of claim 1, wherein the ferroelectric material is an electrostrictive material.

12. The apparatus of claim 1, wherein the selecting means selects the set of pixel posts in real time for animated scene generation.

13. The apparatus of claim 1, wherein infrared light is projected from the light source.

5. A spatial light modulation apparatus for generating an image utilizing light projected from a light source, the apparatus comprising:

a prism having an input end for receiving the projected light, a boundary surface angled for total internal reflection of the projected light received through the input end, and an output end for emitting the projected light reflected from the boundary surface; and

means for eliminating total internal reflection of the projected light at selected pixel areas of the boundary surface thereby to form an image, the eliminating means including

an array of pixel posts each pixel post made of alternate adjacent transverse layers of ferroelectric material and electrically-conductive material, each pixel post having a base end and an opposite free end, the layers of ferroelectric material of each pixel post configured to expand up on being energized to move the free end toward the boundary surface of the prism to eliminate total internal reflection of the projected light at the pixel area corresponding to the free end of the pixel post,

means for selecting from the pixel post array a set of pixel posts to be energized, the set of pixel posts corresponding with the image, and

means for energizing each pixel post of the selected set of pixel posts, the energizing means communicating electrically with the layers of electrically-conductive material to provide an electrical charge to the adjacent layers of ferroelectric material.

6. The apparatus of claim 5, wherein the eliminating means further includes a light-absorbing layer formed on the free end of each pixel post for absorbing the projected light at the pixel area corresponding to the free end when the free end is moved to a position proximate the boundary surface of the prism by selective expansion of the pixel post.

7. The apparatus of claim 5, wherein the pixel post array includes a plurality of pixel posts arranged into rows of pixel posts, each row of pixel posts formed as a monolithic structure from a respective slab comprising the alternate adjacent transverse layers of ferroelectric material and electrically-conductive material;

and further wherein the energizing means includes at least one electrical contact formed on each pixel post, each electrical contact electrically communicating with the layers of electrically-conductive material to provide an electrical charge to the adjacent layers of ferroelectric material.

8. The apparatus of claim 7, wherein two electrical contacts are formed on each pixel post, one of the two electrical contacts electrically communicating with a first series of the layers of electrically-conductive material and being electrically isolated from a second series of the layers of electrically-conductive material, the other of the two electrical contacts electrically communicating with the second series of the layers of electrically-conductive material and being electrically isolated from the first series of the layers of electrically-conductive material.

9. The apparatus of claim 7, wherein divider plates are affixed to and positioned between the respective slabs to provide a spaced-apart relationship between the rows of pixel posts.

10. The apparatus of claim 5 further comprising means for cooling the pixel post array.

14. The apparatus of claim 5, wherein the ferroelectric material is an electrostrictive material.

15. The apparatus of claim 5, wherein the selecting means selects the set of pixel posts in real time for animated scene generation.

16. The apparatus of claim 5, wherein infrared light is projected from the light source.