DIRECTIONAL BACKLIGHT

• US 20140300960A1
• Filed: 06/19/2014
• Published: 10/09/2014
• Est. Priority Date: 05/31/2012
• Status: Active Grant

• Current Assignee: LEIA SPV LLC
• Original Assignee: Leia Inc.
• Inventors: Santori, Charles M., Fattal, David A., Fiorentino, Marco, Brug, James A., Peng, Zhen
• Granted Patent: US 9,459,461 B2
• Time in Patent Office: Days
• US Class Current: 359/462
• CPC Class Codes: G02B 27/4205 having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant
• CPC Class Codes: G02B 30/33 involving directional light or back-light sources
• CPC Class Codes: G02B 6/003 Lens or lenticular sheet or layer
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources

Abstract

A directional backlight is disclosed. The directional backlight has a plurality of light sources to generate a plurality of input planar lightbeams. The plurality of input planar lightbeams illuminates a directional backplane that has a plurality of directional pixels to scatter the plurality of input planar lightbeams into a plurality of directional lightbeams. Each directional lightbeam has a direction and angular spread controlled by characteristics of a directional pixel in the plurality of directional pixels. The directional backlight can be used to generate a 3D image by specifying the characteristics of the directional pixels in the directional backplane.

Claims

1. A directional backlight, comprising:

a plurality of light sources to generate a plurality of input planar lightbeams; and

a directional backplane having a plurality of directional pixels to scatter the plurality of input planar lightbeams into a plurality of directional lightbeams, each directional lightbeam having a direction and angular spread controlled by characteristics of a directional pixel in the plurality of directional pixels.

2. The directional backlight of claim 1, wherein the plurality of light sources comprises a plurality of narrow-bandwidth light sources.

3. The directional backlight of claim 2, wherein the plurality of light sources comprises a plurality of LEDs from the group consisting of:

a single-color LED;

multiple single-color LEDs;

three color LEDs; and

three color LED strips.

4. The directional backlight of claim 3, wherein the three color LEDs comprise a red LED, a green LED, and a blue LED.

5. The directional backlight of claim 3, wherein the three color LED strips comprise a red LED strip, a green LED strip, and a blue LED strip.

6. The directional backlight of claim 1, further comprising a plurality of lens components disposed between the plurality of light sources and the directional backplane.

7. The directional backlight of claim 6, wherein a lens component from the plurality of lens components comprises a lens component from the group consisting of:

a cylindrical lens;

an aspheric condenser lens combined with a cylindrical lens; and

a microlens.

8. The directional backlight of claim 6, further comprising a plurality of optical baffles between the plurality of LEDs and the plurality of lenses.

9. The directional backlight of claim 1, wherein the directional backplane is substantially planar.

10. The directional backlight of claim 1, wherein each directional pixel in the plurality of directional pixels comprises patterned gratings with a plurality of substantially parallel and slanted grooves.

11. The directional backlight of claim 10, wherein the characteristics of a directional pixel comprise a grating length, a grating width, a grating orientation, a grating pitch, and a duty cycle.

12. The directional backlight of claim 11, wherein the pitch and orientation of a directional pixel control the direction of a directional lightbeam scattered by the directional pixel.

13. The directional backlight of claim 11, wherein the length and width of a directional pixel control the angular spread of a directional lightbeam scattered by a directional pixel.

14. A method for generating a 3D image with a directional backlight, comprising:

specifying a plurality of characteristics for a plurality of directional pixels, each directional pixel composed of a patterned grating having substantially parallel and slanted grooves;

fabricating a directional backplane with the plurality of directional pixels arranged thereon;

illuminating the directional backplane with light from a plurality of light sources; and

generating the 3D image with directional lightbeams scattered by the plurality of directional pixels in the directional backplane.

15. The method of claim 14, wherein each directional lightbeam is controlled by the characteristics of a directional pixel.

16. The method of claim 14, wherein the characteristics of a directional pixel comprise a grating length, a grating width, a grating orientation, a grating pitch, and a duty cycle.

17. The method of claim 16, wherein the pitch and orientation of a directional pixel control the direction of a directional lightbeam scattered by the directional pixel.

18. The method of claim 16, wherein the length and width of a directional pixel control the angular spread of a directional lightbeam scattered by the directional pixel.

19. A directional backlight to generate a 3D image, comprising:

a plurality of color LED strips to generate a plurality of input planar lightbeams; and

a polygonal directional backplane having a plurality of directional pixels to scatter the plurality of input planar lightbeams into a plurality of directional lightbeams, each directional lightbeam having a direction and angular spread controlled by characteristics of a directional pixel in the plurality of directional pixels.

20. The directional backlight of claim 19, wherein the polygonal directional backplane comprises a triangular directional backplane.

21. The directional backlight of claim 19, wherein the polygonal directional backplane comprises a hexagonal directional backplane and each color LED strip is disposed on alternating sides of the hexagonal directional backplane.