Projection display employing switchable holographic optical elements

• US 6,424,437 B1
• Filed: 10/10/2000
• Issued: 07/23/2002
• Est. Priority Date: 10/10/2000
• Status: Expired due to Fees

• Current Assignee: Hoya Corporation
• Original Assignee: DigiLens Inc
• Inventors: Popovich, Milan M.
• Primary Examiner(s): Spyrou, Cassandra
• Assistant Examiner(s): BOUTSIKARIS, LEONIDAS
• Application Number:
  US09/685,350
• Time in Patent Office: 651 Days
• Field of Search: 359/15, 359/22, 359/23, 353/30, 353/31, 353/34, 349/5, 349/6, 349/7, 349/8
• US Class Current: 359/15
• CPC Class Codes: G02B 5/32 Holograms used as optical elements
• CPC Class Codes: H04N 5/74 Projection arrangements for image reproduction, e.g. using eidophor
• CPC Class Codes: H04N 9/3102 using two-dimensional electronic spatial light modulators micromechanical modulators as such G02B26/0833; liquid crystal modulators as such G02F1/13

Abstract

The present invention relates to an optical system for use in a projection display system. The optical system, in one embodiment, includes a first electrically switchable holographic optical element (ESHOE) and a light deflector. The first ESHOE operates between active and inactive states and includes oppositely facing front and back surfaces. In the inactive state, the first ESHOE transmits first bandwidth light received on the front surface without substantial alteration. In the active state, the first ESHOE diffracts first bandwidth light received on the front surface, the diffracted first bandwidth light emerging also from the front surface. The light deflector receives first bandwidth light diffracted by the first ESHOE. In response, the light deflector deflects this diffracted first bandwidth light. The first ESHOE and the light deflector are positioned such that first bandwidth light transmitted through the inactive first ESHOE without substantial alteration can illuminate a first surface area while first bandwidth light diffracted by the active first ESHOE and subsequently deflected by the light deflector can illuminate a second non-overlapping.

Claims

1. An apparatus comprising:

a first electrically switchable holographic optical element (ESHOE) comprising oppositely facing front and back surfaces, wherein the first ESHOE is configured to receive first bandwidth light on the front surface thereof, wherein the first ESHOE operates between active and the inactive states, wherein the first ESHOE transmits first bandwidth light received on the front surface thereof without substantial alteration when operating in the inactive state, wherein the first ESHOE diffracts first bandwidth light received on the front surface thereof when operating in the active state, wherein first bandwidth light received and diffracted by the first ESHOE emerges from the front surface;

a light deflector configured to receive first bandwidth light diffracted by the first ESHOE, wherein the light deflector is configured to deflect first bandwidth light diffracted by the first ESHOE;

wherein first bandwidth light transmitted through the inactive first ESHOE without substantial alteration is configured to illuminate a first surface area, and wherein first bandwidth light diffracted by the active first ESHOE and subsequently deflected by the light deflector is configured to illuminate a second surface area, wherein the first surface area is adjacent to the second surface area.

2. The apparatus of claim 1 further comprising an image generator for generating image light, wherein image light generated by the image generator is subsequently received by the front surface of the first ESHOE.

3. The apparatus of claim 2 wherein the image generator is configured to generate first and second light components of a composite image, wherein the second light component is generated subsequent to the generation of the first light component.

4. The apparatus of claim 3 wherein the first ESHOE operates in the inactive state when the first ESHOE receives the first light component generated by the image generator, and wherein the first ESHOE operates in the active state when the first ESHOE receives the second light component generated by the image generator.

5. The apparatus of claim 4 further comprising a display screen, wherein the display screen comprises first and second screen portions, wherein the first and second screen portions comprise the first and second surfaces areas, respectively.

6. The apparatus of claim 5 wherein the light deflector device comprises a mirror.

7. The apparatus of claim 5 wherein the light deflector comprises a holographic optical element configured to diffract light received on a front surface thereof, wherein light diffracted by the holographic optical element emerges from the front surface thereof.

8. The apparatus of claim 1 further comprising:

a first optical component for magnifying light, wherein the first optical component is in optical communication with the first ESHOE and;

a second optical component for magnifying light, wherein the second optical component is in optical communication with the light deflector.

9. The apparatus of claim 1 wherein the first ESHOE comprises a holographic recording medium that records a hologram, wherein the holographic recording medium comprises:

a monomer dipentaerythritol hydroxypentaacrylate;

a liquid crystal;

a cross-linking monomer;

a coinitiator; and

a photoinitiator dye.

10. The apparatus of claim 1 wherein the first ESHOE comprises a hologram made by exposing an interference pattern inside a polymer-dispersed liquid crystal material, the polymer-dispersed liquid crystal material comprising, before exposure:

a polymerizable monomer;

a liquid crystal;

a cross-linking monomer;

a coinitiator; and

a photoinitiator dye.

11. The apparatus of claim 1 further comprising:

a second ESHOE in optical communication with the first ESHOE, wherein the second ESHOE comprises oppositely facing front and back surfaces, wherein the second ESHOE is configured to receive second bandwidth light on the front surface thereof, wherein the second ESHOE operates between active and the inactive states, wherein the second ESHOE transmits second bandwidth light received on the front surface thereof without substantial alteration when operating in the inactive state, wherein the first ESHOE diffracts second bandwidth light received on the front surface thereof when operating in the active state, wherein second bandwidth light received and diffracted by the second ESHOE emerges from the front surface thereof;

wherein the light deflector is configured to receive second bandwidth light diffracted by the second ESHOE, wherein the light deflector is configured to deflect second bandwidth light diffracted by the second ESHOE;

wherein second bandwidth light transmitted through the inactive second ESHOE without substantial alteration is configured to illuminate the first surface area, and wherein second bandwidth light diffracted by the active second ESHOE and subsequently deflected by the light deflector is configured to illuminate the second surface area, wherein the first bandwidth light is different from the second bandwidth light.

12. The apparatus of claim 11 further comprising:

a third ESHOE in optical communication with the first and second ESHOEs, wherein the third ESHOE comprises oppositely facing front and back surfaces, wherein the third ESHOE is configured to receive third bandwidth light on the front surface thereof, wherein the third ESHOE operates between active and the inactive states, wherein the third ESHOE transmits third bandwidth light received on the front surface thereof without substantial alteration when operating in the inactive state, wherein the first ESHOE diffracts third bandwidth light received on the front surface thereof when operating in the active state, wherein third bandwidth light received and diffracted by the third ESHOE emerges from the front surface thereof;

wherein the light deflector is configured to receive third bandwidth light diffracted by the third ESHOE, wherein the light deflector is configured to deflect third bandwidth light diffracted by the second ESHOE;

wherein third bandwidth light transmitted through the inactive third ESHOE without substantial alteration is configured to illuminate the first surface area, and wherein third bandwidth light diffracted by the active third ESHOE and subsequently deflected by the light deflector is configured to illuminate the second surface area, wherein first, second, and third bandwidth lights are different from each other.

13. An apparatus comprising:

an image generator that projects image segments of a composite image in a predetermined direction;

a display screen in optical communication with said image generator to receive and visually display said image segments projected from said image generator; and

projection optics positioned between said image generator and said display screen to selectively direct said image segments to different sections of said display screen to form said composite image on said display screen, said projection optics comprising a first reflective-type reconfigurable holographic optical element having an optical characteristic that is controllable by an electrical field applied thereto, said first reflective-type reconfigurable holographic optical element being holographically configured to diffract one of the image segments to one of said different sections of said display screen when in a diffractive state.

14. The apparatus of claim 13 wherein said first reflective-type reconfigurable holographic optical element of said projection optics is further holographically configured to magnify said one image segment by a defined power when said particular image segment is diffracted by said first reflective-type reconfigurable holographic optical element.

15. The system of claim 13 wherein said projection optics further comprises a second reflective-type reconfigurable holographic optical element, wherein said second reflective-type reconfigurable holographic optical element is holographically configured to correct aberrations introduced by said first reflective-type reconfigurable holographic optical element, wherein said second reflective-type reconfigurable holographic optical element has a controllable optical characteristic that is responsive to a second applied electrical field.

16. The apparatus of claim 13 wherein said first reflective-type reconfigurable holographic optical element is one of a plurality of reflective-type reconfigurable holographic optical elements included in said projection optics, each of said reflective-type reconfigurable holographic optical elements being holographically configured to diffract a respective one of said image segments to a respective one of said different sections of said display screen.

17. An apparatus comprising:

an image forming device for projecting an image;

a display screen comprising first and second display panels for visually displaying images projected by the image forming device;

a switchable holographic device configured to receive the projected image, wherein the switchable holographic device is switchable between active and inactive states, wherein the switchable holographic device is configured to deflect the projected image when active, and wherein the switchable holographic device is configured to transmit the projected image onto the first display panel when inactive;

a light deflector configured to receive the projected image deflected by the switchable holographic device, wherein the light deflector is configured to deflect the projected image deflected by the switchable holographic device onto the second display panel.

18. The apparatus of claim 17 wherein the switchable holographic device comprises holographically recorded interference fringes that at least partially define an optical characteristic of said switchable holographic device.

19. The apparatus of claim 18 wherein the image forming device is configured to project first and second components of a composite image, wherein the second component is generated subsequent to the generation of the first light component, and wherein the second component is generated as the switchable holographic device operates in the active state, and wherein the first component is generated as the switchable holographic device operates in the inactive state.

20. The apparatus of claim 17 wherein the switchable holographic device comprises first, second, and third switchable holograms each of which is switchable between active and inactive states, wherein the first, second, and third switchable holograms, when active, are configured to diffract first, second, and third bandwidth light components, respectively, of the projected image received by the switchable holographic device, and wherein the first, second, and third switchable holograms, when inactive, are configured to pass the first, second, and third bandwidth light components of the projected image received by the switchable holographic device without substantial diffraction.

21. The apparatus of claim 17 further comprising a lens optically positioned between the switchable holographic device and the first display panel, wherein the lens is configured to magnify the projected image transmitted through the switchable holographic device.

22. The apparatus of claim 17 wherein switchable holographic device is configured to switch between the active and inactive states in less than 150 microseconds.