Holographic illumination system

• US 6,317,228 B2
• Filed: 03/14/2001
• Issued: 11/13/2001
• Est. Priority Date: 09/14/1999
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: DigiLens Inc
• Inventors: Popovich, Milan M., Storey, John J., Waldern, Jonathan D.
• Primary Examiner(s): Schuberg, Darren
• Assistant Examiner(s): BOUTSIKARIS, LEONIDAS
• Application Number:
  US09/805,817
• Publication Number:
  US 20010019434A1
• Time in Patent Office: 244 Days
• Field of Search: 359/15, 359/22, 359/24, 359/13, 353/30, 353/31, 353/74, 349/201, 349/202
• US Class Current: 359/15
• CPC Class Codes: G02B 5/32 Holograms used as optical elements
• CPC Class Codes: G02F 1/13342 Holographic polymer dispersed liquid crystals
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence

Abstract

Disclosed is an apparatus and method of illuminating an image display via an electrically switchable holographic optical element. The method includes a first electrically switchable holographic optical element (ESHOE) receiving illumination light. The first ESHOE comprises oppositely facing front and back surfaces. The first ESHOE diffracts a first component (e.g., p-polarized blue light) of the illumination light while transmitting the remaining components of the illumination light without substantial alteration. An image display is provided and receives the diffracted first component. In response to receiving the diffracted first component, the image display emits image light. The first ESHOE receives and transmits this image light without substantial alteration. In one embodiment, the diffracted first component emerges from the first ESHOE at the back surface thereof, and the first ESHOE receives the image light at the back surface thereof so that the image light is received by the first ESHOE in a direction substantially parallel to a direction at which the diffracted first component emerges from the back surface of the first ESHOE.

Claims

1. A method comprising:

a first electrically switchable holographic optical element (ESHOE) receiving illumination light;

the first ESHOE diffracting a first component of the illumination light while transmitting the remaining components of the illumination light without substantial alteration;

an image display receiving the diffracted first component;

image light emitting from the image display in response to the image display receiving the diffracted first component;

the first ESHOE receiving and transmitting the image light without substantial alteration.

2. The method of claim 1 wherein the first ESHOE comprises oppositely facing front and back surfaces, wherein the diffracted first component emerges from the first ESHOE at the back surface thereof, wherein the first ESHOE receives the image light at the back surface thereof, wherein the image light is received by the first ESHOE in a direction substantially parallel to a direction at which the diffracted first component emerges from the back surface of the first ESHOE.

3. The method of claim 2 wherein the first ESHOE receives the illumination light at the front surface thereof, wherein the image light emerges from the first ESHOE at the front surface thereof, wherein a non-zero angle is defined between the illumination light received by the first ESHOE and the image light emerging from the first ESHOE.

4. The method of claim 1, wherein the first ESHOE operates between an active state and an inactive state, wherein the first ESHOE, when operating in the active state, diffracts the first component of the illumination light while transmitting the remaining components of the illumination light without substantial alteration, wherein the first ESHOE, when active, transmits the image light without substantial alteration, and wherein the first ESHOE, when operating in the inactive state, transmits the illumination light including the first component thereof without substantial alteration.

5. The method of claim 1 further comprising the image display reflecting and modulating the diffracted first component to produce the image light.

6. The method of claim 5 wherein the image display modulates the diffracted first component in accordance with image information provided to the image display.

7. The method of claim 1 further comprising the image display reflecting and modifying the diffracted first component to produce the image light, wherein the image display modifies the diffracted first component in accordance with image information provided to the image display device.

8. The method of claim 5 wherein the image light has a polarization state that is orthogonal to the polarization state of the first diffracted light.

9. The method 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 method 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. An apparatus comprising:

a first electrically switchable holographic optical element (ESHOE) for receiving illumination light, wherein the first ESHOE is configured to diffract a first component of the illumination light while transmitting the remaining components of the illumination light without substantial alteration;

an image display for receiving the diffracted first component, wherein the image display is configured to emit image light in response to the image display receiving the diffracted first component;

wherein the first ESHOE is configured to receive and transmit the image light without substantial alteration.

12. The apparatus of claim 11 wherein the first ESHOE comprises oppositely facing front and back surfaces, wherein the diffracted first component emerges from the first ESHOE at the back surface thereof, wherein the first ESHOE is configured to receive the image light at the back surface thereof, wherein the image light is received by the first ESHOE in a direction substantially parallel to a direction at which the diffracted first component emerges from the back surface of the first ESHOE.

13. The apparatus of claim 12 wherein the first ESHOE is configured to receive the illumination light at the front surface thereof, wherein the image light emerges from the first ESHOE at the front surface thereof, wherein a non-zero angle is defined between the illumination light received by the first ESHOE and the image light emerging from the first ESHOE.

14. The apparatus of claim 11 wherein the first ESHOE operates between an active state and an inactive state, wherein the first ESHOE, when operating in the active state, diffracts the first component of the illumination light while transmitting the remaining components of the illumination light without substantial alteration, wherein the first ESHOE, when active, transmits the image light without substantial alteration, and wherein the first ESHOE, when operating in the inactive state, transmits the illumination light including the first component thereof without substantial alteration.

15. The apparatus of claim 11 wherein the image display is configured to reflect and modulate the diffracted first component to produce the image light.

16. The apparatus of claim 15 wherein the image display is configured to modulate the diffracted first component in accordance with image information provided to the image display.

17. The apparatus of claim 15 wherein the image display is configured to reflect and modify the diffracted first component to produce the image light, wherein the image display is configured to modify the diffracted first component in accordance with image information provided to the image display device.

18. The apparatus of claim 15 wherein the image light has a polarization state that is orthogonal to the polarization state of the first diffracted light.

19. The apparatus of claim 11 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.

20. The apparatus of claim 11 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.

21. An apparatus comprising:

an image display;

a light source;

a first switchable holographic optical element (SHOE) disposed between said image display and said light source, wherein said first SHOE operates between active and inactive states, wherein said first SHOE, when operating in the active state, is configured to diffract light of a first bandwidth from said light source to said image display, and wherein said first SHOE is configured to transmit without substantial alteration light of the first bandwidth from said image display into an output direction; and

a second SHOE disposed between said image display and said light source, wherein said second SHOE operates between active and inactive states, wherein said second SHOE is configured to diffract light of a second bandwidth from said light source to said image display, and wherein said second SHOE is configured to transmit without substantial alteration light of the second bandwidth from said image display into the output direction;

wherein the first bandwidth is different from the second bandwidth.