Control of directional display

Patent metadata

Field	Value
Publication number	US-9740034-B2
Application number	US-201415028694-A
Country	US
Kind code	B2
Filing date	Oct 14, 2014
Priority date	Oct 14, 2013
Publication date	Aug 22, 2017
Grant date	Aug 22, 2017

Abstract

Disclosed is a light guiding valve apparatus including an imaging directional backlight, an illuminator array and an observer tracking system arranged to achieve control of an array of illuminators which may provide a directional display to an observer over a wide lateral and longitudinal viewing range, wherein the luminous intensity of optical windows presented to the observer as viewing windows is controlled dependent on the lateral and longitudinal position or speed of an observer. Further an optical window control system may comprise detection of an observer's hand. An image control system may comprise a method to provide an image that can be switched from a first mode with a first brightness into a second mode with a high brightness region and low brightness region, where the brightness of the second low brightness region is matched to the first brightness.

First claim

The invention claimed is:

1. A directional backlight apparatus comprising:
a directional backlight comprising
a waveguide comprising first and second, opposed guide surfaces for guiding input light along the waveguide, and
an array of light sources arranged to generate the input light at different input positions in a lateral direction across the waveguide,
the waveguide further comprising a reflective end for reflecting the input light back through the waveguide, the second guide surface being arranged to deflect light after reflection from the reflective end as output light through the first guide surface, and the waveguide being arranged to direct the output light into optical windows in output directions that are distributed in the lateral direction in dependence on the input position of the input light; and
a sensor system arranged to detect a position of a head of an observer; and
a control system arranged to selectively operate a group of adjacent light sources to direct light into a corresponding group of adjacent optical windows, in a manner in which the identity of the light sources in the group varies, and for a given group of light sources the luminous flux of the light sources varies, in accordance with the detected position of the head of the observer.

2. A directional backlight apparatus according to claim 1 , wherein the luminous flux of the light sources varies across a transitional range of the detected position of the head of the observer.

3. A directional backlight apparatus according to claim 2 , wherein a new light source is operated as a member of the group of adjacent light sources with a luminous flux that increases as the detected position of the head of the observer moves towards the output direction corresponding to the new light source.

4. A directional backlight apparatus according to claim 3 , wherein a light source is operated at an end of the group of adjacent light sources opposite from the new light source with a luminous flux that decreases as the detected position of the head of the observer moves towards the output direction corresponding to the new light source.

5. A directional backlight apparatus according to claim 2 , wherein, across ranges of the detected position of the head of the observer intermediate to the transitional ranges, the identity and luminous flux of the light sources in the group does not vary.

6. A directional backlight apparatus according to claim 1 , wherein the first guide surface is arranged to guide light by total internal reflection and the second guide surface comprises a plurality of light extraction features oriented to direct light guided through the waveguide in directions allowing exit through the first guide surface as the output light and intermediate regions between the light extraction features that are arranged to guide light through the waveguide.

7. A directional backlight apparatus according to claim 6 , wherein the second guide surface has a stepped shape comprising facets, that are said light extraction features, and the intermediate regions.

8. A directional backlight apparatus according to claim 6 , wherein the light extraction features have positive optical power in the lateral direction.

9. A directional backlight apparatus according to claim 1 , wherein
the first guide surface is arranged to guide light by total internal reflection and the second guide surface is substantially planar and inclined at an angle to direct light in directions that break that total internal reflection for outputting light through the first guide surface, and
a deflection element extending across the first guide surface of the waveguide is arranged to deflect light towards the normal to the first guide surface.

10. A directional backlight apparatus according to claim 1 , wherein the reflective end has positive optical power in the lateral direction.

11. A display apparatus comprising:
a backlight apparatus according to any claim 1 ; and
a transmissive spatial light modulator arranged to receive the output light from the first guide surface of the waveguide and to modulate it to display an image.

12. A display apparatus according to claim 11 , being an autostereoscopic display apparatus wherein the control system is further arranged to control the spatial light modulator to display temporally multiplexed left and right images and synchronously to selectively operate groups of adjacent light sources to direct the displayed left and right images into respective groups of adjacent optical windows in positions corresponding to left and right eyes of an observer.

13. A directional display apparatus comprising:
a directional display device capable of directing output light selectively into optical windows of a set of optical windows in output directions that are distributed across the display device; and
a control system arranged to control the display device to direct the output light into at least one selected optical window of the set,
the directional display apparatus being arranged to sense a disposition of a hand of an observer, the control system being arranged to change the control of the display device in response to the sensed disposition of the hand of the observer.

14. A directional display apparatus according to claim 13 , wherein the control system is arranged to shift the at least one selected optical window across the set in response to the directional display apparatus sensing movement of the hand of the observer across the display device in the direction in which the output directions are distributed.

15. A directional display apparatus according to claim 14 , wherein the control system is arranged to change the brightness of the at least one selected optical window in response to the directional display apparatus sensing movement of the hand of the observer across the display device in a direction perpendicular to the direction in which the output directions are distributed.

16. A directional display apparatus according to claim 13 , wherein the control system is arranged to change the number of optical windows that are selected in response to the directional display apparatus sensing a change in separation of fingers of the hand of the observer.

17. A directional display apparatus according to claim 13 , wherein the directional display device is a touch-sensitive directional display device that is arranged to sense the disposition of the hand of the observer in proximity to the directional display device.

18. A directional display apparatus according to claim 13 , further comprising:
an image sensor system arranged to sense the disposition of the hand of the observer.

19. A directional display apparatus according to claim 13 , wherein the directional display device comprises:
a directional backlight capable of directing output light selectively into said optical windows; and
a transmissive spatial light modulator arranged to receive the output light from the directional backlight and to modulate it to display an image.

20. A directional display apparatus according to claim 19 , wherein the directional backlight comprises:
a waveguide comprising first and second, opposed guide surfaces for guiding input light along the waveguide; and
an array of light sources arranged to generate the input light at different input positions in a lateral direction across the waveguide,
the waveguide further comprising a reflective end for reflecting input light back through the waveguide, the second guide surface being arranged to deflect light a

Assignees

• Reald Spark Llc

Inventors

• Woodgate Graham J
• Robinson Michael G
• Hill Adrian J

Classifications

• H04N13/366

  using viewer tracking · CPC title

• H04N13/32

  using arrays of controllable light sources; using moving apertures or moving light sources · CPC title

• G02F1/13338

  Input devices, e.g. touch panels · CPC title

• H04N13/398

  Synchronisation thereof; Control thereof · CPC title

• H04N13/312

  the parallax barriers being placed behind the display panel, e.g. between backlight and spatial light modulator [SLM] · CPC title