OBJECT-SENSING DEVICE

• US 20110234537A1
• Filed: 10/28/2010
• Published: 09/29/2011
• Est. Priority Date: 03/24/2010
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: HWANG, Seong-Mo, HONG, Won-Ki, NAM, Seung-Ho, MIN, Jee-Hong, KIM, Jin-Hwan
• Granted Patent: US 9,019,238 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G06F 2203/04109 FTIR in optical digitiser, i.e. touch detection by frustrating the total internal reflection within an optical waveguide due to changes of optical properties or deformation at the touch location
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

An object-sensing device is presented. The device includes a waveguide and a substrate holding a liquid crystal layer, wherein radiation propagates through the waveguide via total internal reflection. A radiation emitting element is positioned along a radiation input surface of the waveguide, and a radiation receiving element is positioned to receive radiation exiting the waveguide. The radiation receiving element may be positioned across the waveguide from the radiation emitting element. Alternatively, the radiation receiving element may be positioned on a surface that contacts the radiation input surface of the waveguide that is optically coupled to the radiation emitting element.

Claims

1. An object-sensing display device comprising:

a waveguide and a substrate holding a liquid crystal layer, wherein radiation propagates through the waveguide via total internal reflection;

a radiation emitting element positioned along a radiation input surface of the waveguide; and

a radiation receiving element positioned to receive radiation exiting the waveguide.

2. The object-sensing display device of claim 1, further comprising a computer receiving signals from the radiation receiving element to determine a position of the object on the waveguide.

3. The object-sensing display device of claim 1, wherein the radiation receiving element is positioned along an edge of the waveguide and detects the amount of radiation that is transmitted through the waveguide via total internal reflection.

4. The object-sensing display device of claim 1, wherein the radiation receiving element is optically coupled to a surface of the waveguide that is substantially parallel to the radiation input surface.

5. The object-sensing display device of claim 1, wherein the radiation receiving element detects the amount of radiation that is scattered by an object on the waveguide.

6. The object-sensing display device of claim 5, wherein the radiation receiving element is optically coupled to a surface that contacts the radiation input surface.

7. The object-sensing display device of claim 5, wherein the radiation receiving element is optically coupled to a waveguide surface that is substantially perpendicular to the radiation input surface.

8. The object-sensing display device of claim 5, wherein the radiation receiving element is located between the waveguide and the liquid crystal layer.

9. The object-sensing display device of claim 5, wherein the radiation receiving element comprises a plurality of sensors arranged in a two-dimensional configuration.

10. the object-sensing display device of claim 9, wherein the radiation receiving element is arranged in a matrix configuration with each sensor corresponding to a pixel on the substrate.

11. The object-sensing display device of claim 1 further comprising a subsidiary layer disposed on the waveguide, the subsidiary layer having an index of refraction that is lower than that of the waveguide.

12. The object-sensing display device of claim 11, wherein the radiation receiving element is positioned on the subsidiary layer.

13. The object-sensing display device of claim 1, further comprising a black matrix layer formed on the substrate.

14. The object-sensing display device of claim 13, wherein a black matrix of the black matrix layer overlaps the radiation receiving element.

15. The object-sensing display device of claim 1, wherein the substrate comprises a thin film transistor array and pixels.

16. The object-sensing display device of claim 1, wherein the waveguide comprises one of an organic material, glass or polymethyl methacrylate (PMMA).

17. The object-sensing display device of claim 1, wherein the waveguide has a thickness of 0.5-1 mm.

18. The object-sensing display device of claim 1, wherein the radiation receiving element is one of a photodiode, a phototransistor, a charge-coupled device (CCD), and a camera.

19. The object-sensing display device of claim 1, wherein the radiation receiving element is formed on the first substrate.

20. The object-sensing display device of claim 1, wherein the radiation receiving element is formed on the substrate.

21. An object-sensing device comprising:

a waveguide that transmits radiation via total internal reflection from a first end to a second end;

a radiation emitting element positioned at a first end of the waveguide; and

a radiation receiving element positioned at a second end of the waveguide, wherein edges of the waveguide that do not correspond to the first end or the second end are free of radiation emitting element and radiation receiving element.

22. The object-sensing device of claim 21, further comprising a computer receiving signals from the radiation receiving element to determine a position of the object on the waveguide.

23. The object-sensing device of claim 21, wherein the radiation receiving element is positioned along an edge of the waveguide and detects the amount of radiation that is transmitted through the waveguide via total internal reflection.

24. The object-sensing device of claim 21, wherein the radiation receiving element is optically coupled to a surface of the waveguide that is substantially parallel to the radiation input surface.

25. The object-sensing device of claim 21 further comprising a subsidiary layer disposed on the waveguide, the subsidiary layer having an index of refraction that is lower than that of the waveguide.

26. An object-sensing display device comprising:

a waveguide that transmits radiation via total internal reflection from a first end to a second end;

a radiation emitting element positioned at a first end of the waveguide;

a radiation receiving element positioned at a second end of the waveguide, wherein edges of the waveguide that do not correspond to the first end or the second end are free of radiation emitting element and radiation receiving element;

a common electrode formed on the waveguide;

a thin film transistor array substrate having pixel electrodes formed thereon disposed on the common electrode with a liquid crystal layer between the pixel electrodes and the common electrode.

27. A computer-readable medium containing instructions for executing a method for determining the location of an object on a surface in an x-y plane, the method comprising:

obtaining data regarding intensity of radiation at various points along an x-direction;

using a rate of intensity change in the x-direction to determine the y-coordinate of the object, and the point of minimum intensity to determine the x-coordinate of the object.