Optical Position Sensing System and Optical Position Sensor Assembly with Convex Imaging Window

• US 20090237376A1
• Filed: 04/23/2009
• Published: 09/24/2009
• Est. Priority Date: 01/07/2008
• Status: Active Grant

• Current Assignee: Smart Technologies ULC (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Next Holdings Ltd. (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Bridger, Simon James
• Granted Patent: US 8,405,637 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G02B 7/02 for lenses supports for magnifying lenses G02B25/002
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

An optical position sensing system includes a bezel surrounding a display, a position sensor assembly, and a processor for calculating touch locations. Prismatic film may be applied to the bezel. Each optical position sensor assembly includes a body. A lens holder holds an imaging window on a first side and a single element aspherical lens on a second side. The imaging window has an inside face shaped to form a shallow convex surface. The lens holder is mounted to a front face of the body such that the lens is aligned with an opening in the body. An optical sensor is mounted to a rear face of the body and aligned with the opening. A radiation source is positioned within the body above the lens holder and behind an illumination window. A light path separator is positioned between the illumination window and the imaging window.

Claims

1. An optical position sensor assembly, comprising:

a body having a front face and a rear face and an opening therethrough;

a lens holder having a first side and a second side, wherein the first side comprises an imaging window having an inside face that is shaped to form a shallow convex surface, wherein the second side holds a single element aspherical lens such that the lens is aligned with the imaging window, and wherein the lens holder is mounted to the front face of the body such that the lens is aligned with the opening;

an optical sensor mounted to the rear face of the body and positioned such that it is aligned with the opening; and

a radiation source positioned within the body above the lens holder and behind an illumination window.

2. The optical position sensor assembly of claim 1, further comprising a light path separator positioned between the illumination window and the imaging window, such that a path of radiation emitted by the radiation source is optically separated from a view path of the optical sensor.

3. The optical position sensor assembly of claim 2, wherein the light path separator comprises a flexible printed circuit board for driving the radiation source.

4. The optical position sensor assembly of claim 2, wherein the light path separator is an integral component of the lens holder.

5. The optical position sensor assembly of claim 1, wherein the imaging window is dyed to pass a wavelength of radiation emitted by the radiation source and to reject other wavelengths of radiation.

6. The optical position sensor assembly of claim 5, wherein the imaging window is dyed with an optical notch dye.

7. The optical position sensor assembly of claim 1, wherein the lens has an f-theta characteristic.

8. The optical position sensor assembly of claim 1, further comprising an aperture between the second side of the lens holder and the lens.

9. The optical position sensor assembly of claim 1, further comprising an aperture between the lens and the optical sensor.

10. The optical position sensor assembly of claim 1, wherein the lens position is fixed and the focus of the lens is adjusted by changing the position of the optical sensor relative to the body.

11. The optical position sensor assembly of claim 1, wherein the radiation source and the optical sensor are mounted to a flexible printed circuit board.

12. The optical position sensor assembly of claim 1, wherein the body includes one or more alignment features for mounting the optical position sensor assembly to a flat surface.

13. The optical position sensor assembly of claim 1, wherein the optical sensor is encapsulated with an encapsulant;

and

wherein the encapsulant is shaped to form a lensed surface.

14. The optical position sensor assembly of claim 13, wherein the lensed surface is convex in a long axis of a photodiode area of the optical sensor.

15. An optical position sensing system, comprising:

a display;

a bezel surrounding the display;

at least one position sensor assembly for emitting radiation to cause illumination of the bezel and for generating data signals representing detected variations in said illumination;

a processor for processing said data signals to calculate a location of a touch relative to the display; and

wherein each optical position sensor assembly comprises;

a body having a front face and a rear face and an opening therethrough,

a lens holder having a first side and a second side, wherein the first side comprises an imaging window having an inside face that is shaped to form a shallow convex surface and the second side holds a single element aspherical lens that is aligned with the imaging window, and wherein the lens holder is mounted to the front face of the body such that the lens is aligned with the opening,

an optical sensor mounted to the rear face of the body and positioned such that it is aligned with the opening, and

a radiation source positioned within the body above the lens holder and behind an illumination window.

16. The optical position sensing system of claim 15, further comprising a light path separator positioned between the illumination window and the imaging window, such that a path of radiation emitted by the radiation source is optically separated from a view path of the optical sensor.

17. The optical position sensing system of claim 16, wherein the light path separator comprises a flexible printed circuit board for driving the radiation source.

18. The optical position sensing system of claim 16, wherein the light path separator is an integral component of the lens holder.

19. The optical position sensing system of claim 15, further comprising reflectors mounted to a face of the bezel that is perpendicular to a viewing area of the display.

20. The optical position sensing system of claim 19, wherein the reflectors comprise retroreflective material.

21. The optical position sensing system of claim 20, wherein the retroreflective material comprises a prismatic film.

22. The optical position sensing system of claim 15, wherein the at least one optical position sensor assembly is mounted to an overlay that is positioned over the display.

23. The optical position sensing system of claim 15, wherein the imaging window is dyed to pass a wavelength of radiation emitted by the radiation source and to reject other wavelengths of radiation.

24. The optical position sensing system of claim 23, wherein the imaging window is dyed with an optical notch dye.

25. The optical position sensing system of claim 15, wherein the lens has an f-theta characteristic.

26. The optical position sensing system of claim 15, further comprising an aperture between the second side of the lens holder and the lens.

27. The optical position sensing system of claim 15, further comprising an aperture between the lens and the optical sensor.

28. The optical position sensing system of claim 15, wherein the lens position is fixed and the focus of the lens is adjusted by changing the position of the optical sensor relative to the body.

29. The optical position sensing system of claim 15, wherein the radiation source and the optical sensor are mounted to a flexible printed circuit board.

30. The optical position sensing system of claim 15, wherein the body includes one or more alignment features for mounting the optical position sensor assembly to a flat surface.

31. The optical position sensing system of claim 15, wherein the optical sensor is encapsulated with an encapsulant;

and

wherein the encapsulant is shaped to form a lensed surface.

32. The optical position sensing system of claim 31, wherein the lensed surface is convex in a long axis of a photodiode area of the optical sensor.