Optical input using internal reflection surfaces

• US 8,810,515 B2
• Filed: 05/24/2010
• Issued: 08/19/2014
• Est. Priority Date: 05/26/2009
• Status: Active Grant

• Current Assignee: Stmicroelectronics (Research & Development) Limited (STMicroelectronics NV)
• Original Assignee: Stmicroelectronics (Research & Development) Limited (STMicroelectronics NV)
• Inventors: Reigneau, Mathieu, Findlay, Ewan, Brodie, Stuart
• Primary Examiner(s): Nguyen, Chanh
• Assistant Examiner(s): BLANCHA, JONATHAN M
• Application Number:
  US12/786,126
• Publication Number:
  US 20100302160A1
• Time in Patent Office: 1,548 Days
• Field of Search: 345/156, 345/157, 345/166, 356/71, 359/823, 250/221
• US Class Current: 345/166
• CPC Class Codes: G06F 2203/0338 Fingerprint track pad, i.e. fingerprint sensor used as pointing device tracking the fingertip image
• 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 3/03547 Touch pads, in which fingers can move on a surface
• CPC Class Codes: G06F 3/042 by opto-electronic means

Abstract

An optical navigation device for a computer application includes a radiation source capable of producing a beam of radiation, a sensor for receiving an image, and an optical element for identifying movement of the feature to thereby enable a computer action to be carried out. The optical element is formed from a single piece and includes at least one frustrated total internal reflection (F-TIR) surface capable of affecting frustrated total internal reflection of the beam of radiation in the presence of the feature to thereby generate the image.

Claims

1. An optical navigation device, comprising:

a radiation source capable of producing a beam of radiation;

a sensor for receiving an image; and

an optical element for identifying movement of a feature to thereby enable a control action to be carried out;

wherein the optical element comprises at least one biconic surface for directing radiation from the radiation source to at least one F-TIR surface, wherein the at least one biconic surface and the F-TIR surface are angled with respect to each other;

wherein the optical element comprises at least one additional planar surface for directing radiation from the F-TIR surface to the sensor, wherein the at least one additional planar surface and the F-TIR surface are angled with respect to each other;

wherein the radiation measured at the sensor is radiation which is totally internally reflected at the at least one biconic surface, the F-TIR surface, and the at least one additional planar surface;

wherein an imaged area of the F-TIR surface is stretched along a first direction corresponding to a direction of a longitudinal axis of the imaged area, and the image received on the sensor is compressed along the longitudinal axis; and

wherein radiation from the F-TIR surface is reflected off the at least one additional planar surface and focused on the sensor between a circle of least confusion and a position where spatial frequencies in a second direction appear sharper than spatial frequencies in said first direction.

2. The optical navigation device of claim 1, wherein the optical element is formed from a plastics material.

3. The optical navigation device of claim 2, wherein the optical element is formed from PMMA.

4. The optical navigation device of claim 1, wherein the feature comes in contact with an external surface of the optical element in order to produce the frustrated total internal reflection.

5. The optical navigation device of claim 1, wherein the at least one F-TIR surface has an undulating cross-section.

6. The optical navigation device of claim 5, wherein the undulating cross-section defines a contact region at which the feature can come into contact with the surface of the optical element.

7. The optical navigation device of claim 5, wherein the undulating cross-section defines an indented region which prevents reflection of scattered radiation in the optical element.

8. The optical navigation device of claim 1, wherein the at least one F-TIR surface is a domed shape.

9. The optical navigation device of claim 1, wherein movement of the feature is detected at the sensor in the form of the image.

10. The optical navigation device of claim 9, wherein the movement of the feature is measured at a predetermined rate.

11. The optical navigation device of claim 9, wherein the movement of the feature is translated to cause the control action to occur.

12. The optical navigation device of claim 1, wherein the control action is applied to control a computer device.

13. A device, comprising:

an optical navigation device, comprising;

a radiation source capable of producing a beam of radiation;

a sensor for receiving an image;

an optical element for identifying movement of a feature to thereby enable a control action to be carried out;

wherein the optical element is formed from a single piece construction and includes at least one frustrated total internal reflection (F-TIR) surface capable of causing frustrated total internal reflection of the beam of radiation in the presence of the feature to thereby generate the image which is capable of being translated into said control action;

wherein the optical element comprises at least one biconic surface for directing radiation from the radiation source to the at least one F-TIR surface, wherein the at least one biconic surface and the at least one F-TIR surface are angled with respect to each other;

wherein the optical element comprises at least one folded surface for directing radiation from the at least one F-TIR surface to the sensor, wherein the at least one folded surface and the at least one F-TIR surface are angled with respect to each other; and

wherein the radiation measured at the sensor is radiation which is totally internally reflected at the at least one biconic surface, the at least one F-TIR surface and the at least one folded surface.

14. The device of claim 13 wherein the device is one of a mobile telephone or a computer.

15. The device of claim 14, wherein an imaged area on the at least one F-TIR surface is rectangular and stretched in one particular direction, wherein a longitudinal axis of the imaged area includes an angle of 80°

to 100 with the longitudinal axis of the computer or the mobile telephone or an axis perpendicular to the longitudinal axis of the computer device or the mobile telephone.

16. The device of claim 15, wherein the longitudinal axis of the imaged area is perpendicular or parallel to the longitudinal axis of the mobile telephone.

17. The device of claim 15, wherein the longitudinal axis of the imaged area is parallel to an axis connecting the radiation source and the sensor.

18. The device of claim 15, wherein the imaged area is located at the center of the at least one F-TIR surface.

19. The device of claim 15, wherein the optical navigation device comprises at least one prism in form of a trapezoid, wherein the imaged area in operation of the optical navigation device is formed on a longer basis side of the at least one prism.

20. The device of claim 15, wherein a focus at which the imaged area is focused between one member of a group comprising a circle of least confusion and a position in which the imaged area is sharper in a direction perpendicular to the horizontal axis of the imaged area.

21. An optical device, comprising:

a first surface adapted to receive an input beam of radiation;

a second surface adapted to output an image;

a third surface to which a feature to be detected is applied;

an optical element having an outer surface defined at least in part by the first, second and third surfaces, the optical element further comprising;

a) a frustrated total internal reflection (F-TIR) surface associated with the third surface;

b) a first internal reflecting surface comprising a biconic surface adapted to reflect the input beam of radiation received at the first surface towards the frustrated total internal reflection (F-TIR) surface; and

c) a second internal reflecting surface comprising a planar or folded surface adapted to reflect the image on frustrated total internal reflection (F-TIR) surface for output at the second surface.

22. The optical device of claim 21, wherein the third surface and associated F-TIR surface have an undulating cross-section.

23. The optical device of claim 22, wherein the undulating cross-section includes a domed feature contact region and an indented region surrounding the domed feature.

24. The optical device of claim 21, wherein the third surface and associated F-TIR surface have a domed shape.

25. The optical device of claim 21 wherein presence of the feature applied to the third surface causes frustrated total internal reflection of the received beam of radiation to thereby generate the image.

26. The optical device of claim 21 wherein the single piece optical element further includes a projection forming a clip for snap-fit connection to a support structure.

27. The optical device of claim 21, wherein an imaged area on the F-TIR surface is rectangular and wherein a longitudinal axis of the rectangular imaged area is parallel to an axis connecting between the first and second surfaces.

28. The optical device of claim 27, wherein the imaged area is located at a center of the F-TIR surface.

29. The optical device of claim 21, wherein the single piece optical element comprises at least one prism in form of a trapezoid, wherein an imaged area in operation of the optical device is formed on a longer basis side of the at least one prism.

30. The optical device of claim 29, wherein a point at which the imaged area is focused is located between a circle of last confusion and a position in which the imaged area is sharper in a direction perpendicular to the horizontal axis of the imaged area.

31. The optical device of claim 21, wherein the optical element further comprises an additional internal reflecting surface adapted to receive the input beam reflected by the fly-eye lens and reflect the input beam toward the F-TIR surface.

32. The optical device of claim 31, wherein the input beam is totally internally reflected by the additional internal reflecting surface.