LIGHT REDIRECTION HOLOGRAM FOR REFLECTIVE DISPLAYS

• US 20150130896A1
• Filed: 05/08/2014
• Published: 05/14/2015
• Est. Priority Date: 11/08/2013
• Status: Abandoned Application

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Ma, Jian, Li, Kebin, Hong, John Hyunchul, Chang, Tallis Young
• Application Number:
  US14/272,913
• Publication Number:
  US 20150130896A1
• Time in Patent Office: Days
• US Class Current: 348/40
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G02B 5/0252 using holographic or diffractive means
• CPC Class Codes: G02B 5/32 Holograms used as optical elements
• CPC Class Codes: G03H 1/0005 Adaptation of holography to specific applications holographic optical element G02B5/32; holographic scanner G02B26/106; recognition using holographic mask G06V10/88; holographic memories G11B7/0065, G11C13/042
• CPC Class Codes: G03H 1/20 Copying holograms by holographic , i.e. optical means
• CPC Class Codes: G03H 2001/0077 for optical manipulation, e.g. holographic optical tweezers [HOT]
• CPC Class Codes: G03H 2001/0088 for video-holography, i.e. integrating hologram acquisition, transmission and display
• CPC Class Codes: G03H 2001/0439 for recording Holographic Optical Element [HOE] HOE per se G02B5/32
• CPC Class Codes: G03H 2222/18 RGB trichrome light

Abstract

This disclosure provides systems, methods and apparatus for enhancing the brightness and/or contrast ratio of display devices. In one aspect, the display devices can include a light redirector that is optically coupled with a diffuser. The light redirector includes a plurality of holographic features that can receive near-collimated light at non-normal angles with respect to a normal to a surface of the light redirector and redirects the received light along a direction that is substantially normal to the surface.

Claims

1. A light redirector comprising:

a light receiving surface having a surface normal and configured to receive near-collimated light from an incidence direction that is at an angle with respect to the surface normal, and wherein a direction of specular reflection is associated with the incidence direction; and

a holographic layer including a plurality of transmissive holographic light redirecting features that are configured to redirect and diffuse the received light substantially along a direction that is within ±

20 degrees with respect to the surface normal towards a side opposite the light receiving surface.

2. The light redirector of claim 1, wherein the incidence direction forms an angle between about 20 degrees and about 50 degrees with respect to the surface normal.

3. The light redirector of claim 1, wherein the holographic layer has a thickness between about 5 μ

m and about 50 μ

m.

4. The light redirector of claim 1, wherein the plurality of holographic light redirecting features are configured such that light incident from the side opposite to the light receiving surface in an angular range that is within ±

10 degrees with respect to the surface normal is not redirected by the plurality of holographic light redirecting features.

5. The light redirector of claim 1, wherein the plurality of holographic light redirecting features include volume holograms.

6. A display device including the light redirector of claim 1 disposed over a reflective display element.

7. The display device of claim 6, wherein the reflective display element includes at least one interferometric modulator.

8. The display device of claim 6, wherein the reflective display element is disposed on a first side of a substrate and the light redirector is disposed on a second side of the substrate opposite the first side.

9. The display device of claim 6, further comprising:

a processor that is configured to communicate with the display, the processor being configured to process image data; and

a memory device that is configured to communicate with the processor.

10. The display device of claim 9, further comprising a driver circuit configured to send at least one signal to the display element.

11. The display device of claim 10, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

12. The display device of claim 9, further comprising an image source module configured to send the image data to the processor.

13. The display device of claim 12, wherein the image source module includes at least one of a receiver, transceiver, and transmitter.

14. The display device of claim 9, further comprising an input device configured to receive input data and to communicate the input data to the processor.

15. The light redirector of claim 1, wherein the holographic layer functions as a light redirector and a light diffuser.

16. The light redirector of claim 1, wherein the holographic layer is a single optical element that is a light redirector and a light diffuser.

17. A light redirector comprising:

a light receiving surface having a surface normal and configured to receive near-collimated light from an incidence direction that is at an angle with respect to the surface normal, and wherein a direction of specular reflection is associated with the incidence direction; and

a layer including a plurality of transmissive means for holographically redirecting light, the transmissive light redirecting means configured to redirect and diffuse the received light substantially along a direction that is within ±

20 degrees with respect to the surface normal towards a side opposite the light receiving surface.

18. The light redirector of claim 17, wherein the plurality of transmissive light redirecting means includes a plurality of transmissive holographic features.

19. The light redirector of claim 18, wherein the transmissive holographic features include volume holograms.

20. The light redirector of claim 17, wherein the layer is a single optical element that is a light redirector and a light diffuser.

21. A method of manufacturing a light redirector, the method comprising:

providing a substrate including a light receiving surface having a surface normal and configured to receive near-collimated light from an incidence direction that is at an angle with respect to the surface normal, and wherein a direction of specular reflection is associated with the incidence direction;

disposing a plurality of transmissive holographic light redirecting features with respect to the substrate, the plurality of transmissive holographic light redirecting features configured to redirect and diffuse the received light substantially along a direction that is within ±

20 degrees with respect to the surface normal towards a side opposite the light receiving surface.

22. The method of claim 21, wherein disposing a plurality of transmissive holographic light redirecting features further comprises:

disposing a first holographic medium forward or rearward of the light receiving surface; and

forming the plurality of transmissive holographic features in the first holographic medium.

23. The method of claim 22, wherein the first holographic medium includes a photopolymer.

24. The method of claim 22, wherein the plurality of transmissive holographic features is formed by replicating a plurality of holographic features included in a master hologram on the first holographic medium using a single coherent multi-wavelength laser beam.

25. The method of claim 24, wherein the master hologram including the plurality of holographic features is recorded using two coherent laser beams incident on a second holographic medium, the two beams including multiple wavelengths in blue, green and red spectral regions.

26. The method of claim 25, wherein a diffuser is disposed in the optical path of one of the two beams.

27. The method of claim 25, wherein the plurality of holographic light redirecting features are recorded with one of the coherent laser beams being incident on the second holographic medium at different azimuthal angles.