Scanning liquid-crystal display backlight

Patent metadata

Field	Value
Publication number	US-2015277551-A1
Application number	US-201414224850-A
Country	US
Kind code	A1
Filing date	Mar 25, 2014
Priority date	Mar 25, 2014
Publication date	Oct 1, 2015
Grant date	—

Abstract

A display includes an optical waveguide with opposing front and back faces, an injection optic, and volume hologram arranged on or within the waveguide. The injection optic is configured to inject light into the waveguide at a variable injection angle, which influences the reflection angle at which the light reflects from the front and back faces on propagating through the waveguide. The hologram is configured to release, in a predetermined direction, a portion of the light from the waveguide when excited at a predetermined reflection angle.

First claim

1 . A display comprising:
an optical waveguide with opposing front and back faces; an injection optic configured to inject light into the waveguide at a variable injection angle, the injection angle influencing a reflection angle at which the light reflects from the front and back faces on propagating through the waveguide; and arranged on or within the waveguide, a hologram configured to release a portion of the light from the waveguide when excited at a predetermined reflection angle.

2 . The display of claim 1 , wherein the hologram is arranged on the front or back face of the waveguide.

3 . The display of claim 1 , wherein the waveguide includes an edge face adjacent the front and back faces, and wherein the injection optic is configured to inject the light into the edge face.

4 . The display of claim 3 , wherein the controlled angle is an elevation angle.

5 . The display of claim 1 , wherein the waveguide includes a plurality of display zones with a different injection optic provided for each zone.

6 . The display of claim 5 , wherein the hologram is one of a plurality of volume holograms superposed in a light-extraction layer arranged on or within the waveguide, and wherein each volume hologram is configured to release the light in a predetermined, different direction when excited at a corresponding reflection angle.

7 . The display of claim 1 , wherein each volume hologram is a Bragg grating.

8 . The display of claim 6 , wherein the plurality of volume holograms extends across all of the display zones.

9 . The display of claim 1 , wherein the injection optic includes red, green, and blue lasers emitting onto a movable mirror, and wherein the injection angle is controlled via deflection of the mirror.

10 . The display of claim 1 , wherein the hologram is a grating hologram, wherein the waveguide is one of a plurality of stacked waveguides each supporting a different grating hologram, and wherein each grating hologram is configured to release the light in a predetermined, different direction.

11 . The display of claim 10 wherein the variable injection angle determines which of the plurality of waveguides receives the light from the injection optic.

12 . A display comprising:
an optical waveguide with opposing front and back faces; an injection optic configured to inject light into the waveguide at a variable injection angle, the injection angle influencing a reflection angle at which the light reflects from the front and back faces while propagating through the waveguide; arranged on or within the waveguide, a hologram configured to release a portion of the light from the waveguide when excited at a predetermined reflection angle; a liquid-crystal layer with an array of pixels positioned in front of the waveguide, the liquid-crystal layer controlling a transmission of the light through each pixel of the array; a camera configured to acquire an image of a viewer of the display; and a display-directing engine configured to control the injection angle based on the image, so that a direction of release of the light from the waveguide is toward a pupil of the viewer.

13 . The display of claim 12 , wherein the camera is a depth camera configured to resolve distance to the pupil.

14 . The display of claim 12 , further comprising a pupil-tracking engine configured to compute coordinates of the pupil, wherein the coordinates of the pupil include distance to the pupil.

15 . The display of claim 12 , wherein the waveguide includes a plurality of zones with a different injection optic provided for each zone.

16 . The display of claim 15 , wherein the display zones run vertical, and wherein the injection angle is responsive to a horizontal position of the pupil relative to the display.

17 . The display of claim 15 , wherein the display zones run horizontal, and wherein the injection angle is responsive to a vertical position of the pupil relative to the display.

18 . Enacted in a computer system having a display, a method to concentrate light into a pupil of a viewer of the display, the method comprising:
acquiring an image of the viewer; recognizing a position of the pupil based on the image; computing a direction for release of light based on the position of the pupil; and injecting light into the waveguide at a variable injection angle to cause the light to reflect from front and back faces of the waveguide at a reflection angle that excites one of a plurality of holograms, the excited hologram being configured to release the light in the computed direction for release.

19 . The method of claim 18 , wherein the waveguide includes plurality of zones, wherein light is injected into the waveguide at a different angle for each zone, and wherein the pupil is one of a plurality of pupils of one or more viewers of the display, the method further comprising:
providing, for each pupil, a time window during which the light is injected into the waveguide at an injection angle to cause excitation of the hologram that concentrates light toward that pupil.

20 . The method of claim 18 , wherein the waveguide includes plurality of zones, and wherein light is injected into the waveguide at a different angle for each zone, the method further comprising deactivating a display zone from which light cannot be directed into the pupil.

Assignees

• Microsoft Corp

Inventors

• Travis Adrian

Classifications

• G02F1/133621

  providing coloured light (G02F1/133617, G02F1/133533 take precedence) · CPC title

• G02B6/0035 Primary

  provided on the surface of the light guide or in the bulk of it · CPC title

• G02B6/0068

  Arrangements of plural sources, e.g. multi-colour light sources · CPC title

• G02B6/0066

  characterised by the light source being coupled to the light guide · CPC title

• G06F3/013 Primary

  Eye tracking input arrangements (G06F3/015 takes precedence) · CPC title