Electrically switchable field of view for embedded light sensor

• US 8,072,442 B2
• Filed: 02/09/2010
• Issued: 12/06/2011
• Est. Priority Date: 02/09/2010
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Baum, Alexandra, Yu, Jing, Suckling, James Rowland, Brown, Christopher James, Castagner, Jean-Luc Laurent
• Primary Examiner(s): DHARIA, PRABODH M
• Application Number:
  US12/702,972
• Publication Number:
  US 20110193822A1
• Time in Patent Office: 665 Days
• Field of Search: 345/55, 345/72, 345 87-104, 345173-178, 345/204, 348/252, 348/332, 349/12, 349/14, 349/61, 349/106, 349/156, 349/1, 349/11, 349/193, 359/265, 359/267, 359601-604, 359/453, 359/499
• US Class Current: 345/175
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/042 by opto-electronic means

Abstract

A display device for detecting light includes a display surface, at least one light sensitive element arranged behind the display surface, and a liquid crystal element arranged between the display surface and the at least one light sensitive element. The liquid crystal element is operative to polarization shift light incident on the at least one light sensitive element based on an orientation of the plurality of molecules. The display device further includes at least one electrode operative to change an orientation of the plurality of molecules. The at least one electrode is patterned to define a geometry of at least one field of view of the at least one light sensitive element. A controller is electrically coupled to the at least one electrode, wherein the controller is configured to apply a voltage to the at least one electrode to effect selection of the at least one field of view.

Claims

1. A display device for detecting light, comprising:

a liquid crystal display element including at least one electrode patterned thereon; and

at least one light sensitive element arranged behind the liquid crystal display element, wherein the at least one electrode, in conjunction with a voltage applied to the liquid crystal display element via the at least one electrode, is operative to change an optical transmission characteristic of the liquid crystal display element to define at least one field of view of the at least one light sensitive element relative to light transmitted through the liquid crystal display element, and

wherein the at least one electrode is patterned to define a geometry of the at least one field of view of the at least one light sensitive element.

2. The display device according to claim 1, wherein the liquid crystal display element is operative to polarization shift light incident on the at least one light sensitive element.

3. The device according to claim 1, further comprising a controller electrically coupled to the at least one electrode, the controller configured to apply a voltage to the at least one electrode to effect selection of the at least one field of view.

4. The device according to claim 1, further comprising an in-cell polarizing element arranged in the liquid crystal element.

5. The device according to claim 4, wherein the liquid crystal element is arranged over the in-cell polarizing element.

6. The device according to claim 4, wherein the in-cell polarizing element is arranged within the liquid crystal element.

7. The device according to claim 1, further comprising at least one electronic layer, wherein the at least one light sensitive element is embedded within the at least one electronic layer.

8. The device according to claim 1, further comprising a polarizing element arranged over the liquid crystal element, the polarizing element configured to linearly polarize light incident on the at least one light sensitive element.

9. The device according to claim 1, further comprising a polarizing element arranged under the liquid crystal element, the polarizing element configured to linearly polarize light incident on the at least one light sensitive element.

10. The device according to claim 1, wherein the at least one electrode is arranged such that a position and shape of the at least one electrode relative to the at least one light sensitive element induces the field of view of the at least one light sensitive element toward a predetermined direction.

11. The device according to claim 1, wherein when the liquid crystal element is in a first state, incident polarized light is either transmitted through the liquid crystal element and impinges on a surface of the at least one light sensitive element, or the incident polarized light blocked from passing through the liquid crystal element, wherein the at least one light sensitive element generates a scaled signal corresponding to a light input pixel.

12. The device according to claim 1, wherein the at least one electrode is patterned in a rectangular, square, circular, or elliptical shape.

13. The device according to claim 1, wherein the at least one electrode is a ground electrode and positioned adjacent to an edge of another electrode.

14. The device according to claim 13, wherein the ground electrode is patterned in a rectangular, square, circular, or elliptic shape.

15. The device according to claim 1, wherein the at least one electrode comprises a plurality of electrodes patterned in distinct regions above the at least one light sensitive element.

16. The device according to claim 15, wherein the distinct regions are electrically isolated from one another, and distinct fields of view of the at least one light sensitive element are electrically selectable based on a voltage applied to one or more of the distinct regions.

17. The device according to claim 16, wherein switching of each field of view is made on a pixel-by-pixel basis.

18. The device according to claim 1, wherein the at least one light sensitive element comprises a color filter.

19. The device according to claim 18, wherein adjacent light sensitive elements of the plurality of light sensitive elements have fields of view that co-extend to fields of view of adjacent light sensitive elements.

20. The device according to claim 1, further comprising an optical element arranged over the at least one light sensitive element, the optical element configured to modify a direction of the field of view of the at least one light sensitive element to be normal to a surface of the display device.

21. The device according to claim 20, wherein the optical element comprises a lens array.

22. The device according to claim 1, further comprising an optical element arranged over the at least one light sensitive element, the optical element configured to modify a direction of the field of view of the at least one light sensitive element to be at an angle to the normal of a surface of the display device.

23. The device according to claim 22, wherein the optical element comprises a lens.

24. The device according to claim 1, wherein the light sensitive element is responsive to non-homogeneous light.

25. The device according to claim 1, wherein the at least one electrode is patterned such that only incident light from a distinct field of view of the at least one light sensitive element impinges on a predetermined area of the at least one light sensitive element, and the incident light is contained within a total internal refraction limit such that the incident light does not impinge on another part of the at least one light sensitive element associated with a different field of view.

26. The device according to claim 1, further comprising a reflective electrode arranged over the at least one electrode, the reflective electrode patterned to include an aperture arranged over the at least one electrode.

27. The device according to claim 1, further comprising an infrared light source arranged below the at least one light sensitive element so as to transmit infrared radiation through the liquid crystal element and illuminate objects above a surface of the display device such that scattered infrared radiation is incident on the at least one light sensitive element.

28. The device according to claim 1, wherein the at least one electrode is arranged over the at least one light sensitive element.

29. The device according to claim 1, further comprising a light source, wherein the at least one light sensitive element is arranged between the light source and the liquid crystal display element.

30. A display device for detecting light incident within an electrically selectable field of view, comprising:

at least one electronic layer including at least one light sensitive element;

a liquid crystal element arranged over the at least one light sensitive element and including a plurality of molecules, wherein the liquid crystal element is operative to polarization shift light incident on the at least one light sensitive element based on an orientation of the plurality of molecules; and

at least one electrode operative to change an orientation of the plurality of molecules, the at least one electrode patterned to define a geometry of a field of view of the at least one light sensitive element,

wherein light passing through the at least one electronic layer undergoes polarization-by-reflection, and a field of view of the at least one light sensitive element is bounded by the angular dependence of the polarization-by-reflection.