OPTICAL NAVIGATION DEVICE

• US 20100302159A1
• Filed: 05/24/2010
• Published: 12/02/2010
• Est. Priority Date: 05/26/2009
• Status: Active Grant

• Current Assignee: STMicroelectronics Limited (STMicroelectronics NV)
• Original Assignee: STMicroelectronics Limited (STMicroelectronics NV)
• Inventors: Brodie, Douglas Stuart, Findlay, Ewan
• Granted Patent: US 8,525,789 B2
• Time in Patent Office: Days
• 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 includes an optical transmission element, operable in use to transmit light from an illumination source to a sensor via a mousing surface, and a housing unit. The optical transmission element may have an alignment shaft. Ideally the optical transmission element and housing unit are assembled to a substrate by snap-fit. The alignment shaft ensures that the optics are properly aligned to the substrate and the light source and sensor thereon.

Claims

1. An optical navigation device comprising:

an optical transmission element which provides a mousing surface and which, in use, transmits radiation from an illumination source to a sensor via said mousing surface, and

a housing element for providing a housing for said illumination source, sensor and optical transmission element.

2. The optical navigation device of claim 1 wherein said mousing surface is of a type that is operable by moving a digit over the mousing surface such that the digit'"'"'s movement is detectable.

3. The optical navigation device of claim 1 wherein the optical transmission element and housing element are attachable together to a base by snap-fitting the optical transmission element and housing element and base together without the need of adhesive or similar.

4. The optical navigation device of claim 3 wherein said optical transmission element comprises a shaft extending from a center of its underside for aligning the optical transmission element to the base.

5. The optical navigation device of claim 4 wherein said optical transmission element is provided with a first attachment mechanism such that, when said optical transmission element is pushed into said main housing element and partly through at least one aperture in said base, said first attachment mechanism cooperates with said base so as to lock said base and optical transmission element and housing element together.

6. The optical navigation device of claim 5 wherein said first attachment mechanism is operable to deform to allow it to be pushed through said at least one aperture in said base, a part of said first attachment mechanism then being operable to abut against the underside of said base to lock said optical transmission element, and said main housing element, in place.

7. The optical navigation device of claim 5 wherein said first attachment mechanism is located at or near the bottom end of said shaft thereby, in use, aligning said optical transmission element to the lower surface of the base.

8. The optical navigation device of claim 5 wherein said first attachment mechanism is located at one or more points separate from said shaft, said shaft comprising at its end at least one abutment for abutting against the upper surface of said base, thereby aligning said optical transmission element to said upper surface of the base.

9. The optical navigation device of claim 5 arranged such that a force is required to push said first attachment mechanism through the base and lock, the assembled device thereafter remaining under tension.

10. The optical navigation device of claim 9 wherein said force is resultant from the main housing element or a gasket located between the main housing element.

11. The optical navigation device of claim 9 wherein a kinematic coupling is provided between said optical transmission element and said base.

12. The optical navigation device of claim 4 further comprising a second attachment mechanism for attaching together optical transmission element and housing element prior to final assembly to a base, said attachment being effected by pushing said optical transmission element into said main housing element until said second attachment mechanism actuates so as to hold the optical transmission element and housing element together.

13. The optical navigation device of claim 12 wherein said second attachment mechanism is located on an intermediate point of said shaft.

14. The optical navigation device of claim 1 wherein said optical transmission element is formed from a single piece of material, preferably plastic.

15. The optical navigation device of claim 14 wherein said single piece of material comprises input and output lenses.

16. The optical navigation device of claim 15 wherein said main housing element comprises integrally an optical stop which forms an aperture for one of said lenses, preferably the output lens.

17. The optical navigation device of claim 1 wherein said housing element comprises walls which prevent light from said illumination source being transmitted to said sensor other than via said optical transmission element.

18. The optical navigation device of claim 1 wherein said optical navigation device incorporates an integral switch.

19. The optical navigation device of claim 18 wherein said switch is located below said base.

20. The optical navigation device of claim 18 wherein said optical navigation device is operable such that said optical transmission element is the actuator interface to operate the switch.

21. The optical navigation device of claim 20 wherein said switch is a domed switch.

22. An optical navigation device comprising:

a main housing element and an optical transmission element,

said optical transmission element being operable in use to transmit light from an illumination source to a sensor via a mousing surface,

said optical transmission element comprising an alignment shaft which, when assembling said optical transmission element and said main housing element to a base, is operable to align said optical transmission element to said base.

23. The optical navigation device of claim 22 wherein said mousing surface is of a type that is operable by moving a digit over the mousing surface such that the digit'"'"'s movement is detectable.

24. The optical navigation device of claim 22 wherein said optical transmission element is formed from a single piece of material, preferably plastic.

25. The optical navigation device of claim 22 wherein said optical transmission element comprises input and output lenses.

26. The optical navigation device of claim 25 wherein said main housing element comprises integrally an optical stop which forms an aperture for one of said lenses, preferably the output lens.

27. The optical navigation device of claim 25 wherein said alignment is such that input and output lenses provided on said optical transmission element are aligned with said illumination source and sensor, said illumination source and sensor being comprised with the base.

28. The optical navigation device of claim 22 comprising a first attachment mechanism operable to hold together said main housing element and said optical transmission element to said base by snap-fitting said elements and base together without the need of adhesive or similar.

29. The optical navigation device of claim 28 wherein said first attachment mechanism is operable, during assembly, to be pushed through said main housing element and at least partly through at least one aperture in said base, until said first attachment means cooperates with said base so as to lock both the main housing element and optical transmission element together to said base.

30. The optical navigation device of claim 29 wherein said snap fitting should be such that a force is required to push said first attachment mechanism through the base to lock, the assembled device remaining under tension.

31. The optical navigation device of claim 30 wherein said force is provided by the main housing element or a gasket located between the main housing element and the base.

32. The optical navigation device of claim 30 wherein a kinematic coupling is provided between said optical transmission element and said base.

33. The optical navigation device of claim 28 wherein said alignment shaft comprises said first attachment mechanism at its end such that, when assembled, said first attachment mechanism abuts against the underside of said base thereby aligning said optical transmission element to the lower surface of the base.

34. The optical navigation device of claims 28 wherein said first attachment mechanism is located at one or more points separate from said shaft, said shaft comprising at its end at least one abutment for abutting against the upper surface of said base, thereby aligning said optical transmission element to said upper surface of the base.

35. The optical navigation device of claim 22 wherein said alignment shaft extends from a center of the underside of said optical transmission element.

36. The optical navigation device of claim 22 further comprising a second attachment mechanism for attaching together the main housing element and optical transmission element prior to final assembly, said attachment being effected by pushing said optical transmission element into said main housing element until said second attachment mechanism actuates so as to hold the main housing element and optical transmission element together.

37. The optical navigation device of claim 36 wherein said second attachment mechanism is located at an intermediate point on said alignment shaft.

38. The optical navigation device of claim 22 wherein said optical navigation device incorporates an integral switch.

39. The optical navigation device of claim 38 wherein said switch is located below said base.

40. The optical navigation device of claim 38 wherein said optical navigation device is operable such that said optical transmission element is the actuator interface to operate the switch.

41. The optical navigation device of claim 40 wherein said switch is a domed switch.

42. The optical navigation device of claim 22 comprising a frustrated total internal reflection (F-TIR) device wherein an object contacting the mousing surface frustrates the total internal reflection of said light in said optical transmission element.

43. An optical navigation device comprising:

an optical transmission element which provides a mousing surface and which, in use, transmits radiation from an illumination source to a sensor via said mousing surface, and

a main housing element, for providing a housing for said illumination source, sensor and optical transmission element such that said illumination source and sensor are housed separately from said optical transmission element.