Pointing device utilizing a photodetector array

• US 5,907,152 A
• Filed: 06/19/1997
• Issued: 05/25/1999
• Est. Priority Date: 10/05/1992
• Status: Expired due to Term

• Current Assignee: Logitech Europe S A (Logitech International SA)
• Original Assignee: Logitech, Inc. (Logitech International SA)
• Inventors: Bidiville, Marc, Dandliker, Rene
• Primary Examiner(s): Westin, Edward P.
• Assistant Examiner(s): Lee, John R.
• Application Number:
  US08/878,661
• Time in Patent Office: 705 Days
• Field of Search: 250/221, 250/222.1, 250/229, 250/214.1, 250/214 R, 250/215, 250/231.12, 250/231.13, 250/231.14, 250/231.16, 250/231.18, 250/208.2 , 250/208.5, 250/559.23, 345/156, 345/157, 345/158, 345/159, 345/163, 345/164, 345/165, 345/166, 345/167, 356/375, 356/376
• US Class Current: 250/221
• CPC Class Codes: G06F 3/0317 in co-operation with a patterned surface, e.g. absolute position or relative movement detection for an optical mouse or pen positioned with respect to a coded surface
• CPC Class Codes: G06F 3/03543 Mice or pucks G06F3/03541 takes precedence
• CPC Class Codes: G06F 3/03547 Touch pads, in which fingers can move on a surface
• CPC Class Codes: G06F 3/03549 Trackballs G06F3/03541 takes precedence
• CPC Class Codes: G06F 3/0383 Signal control means within the pointing device

Abstract

An optical detection system particularly suited to us as a pointing device uses a photodetector array capable of generating a quasi-sinusoidal signal in response to illumination with an image of appropriate size. The detection system can use either coherent or non-coherent light, and existing textures in standard materials such as paper or printed patterns.

Claims

1. An optical detection system comprising:

an aperture;

a lens positioned near said aperture, for receiving a light signal reflected from a surface and though said aperture, for focusing said light signal to form a focused light signal;

a fist detection system for detecting displacement along a first dimension, comprising;

a comb pbotodetector array, optically matched with said lens and said aperture, for receiving said focused light signal, said focused light signal having light and dark portions representing a pattern caused by said light signal reflecting off of the surface, said comb photodetector having first, second, third, fourth, fifth, sixth, seventh, and eighth elements, said first and fifth elements are coupled to generate a first comb signal, said second and sixth elements are coupled to generate a second comb signal, said third and seventh elements are coupled to generate a third comb signal, and said fourth and eighth elements are coupled to generate a fourth comb signal;

a generation unit, for combining said first and second comb signals to generate a first quasi-sinusoidal signal, for combining said third and fourth comb signals to generate a second quasi-sinusoidal signal, wherein said first and second quasi-sinusoidal signals are analog quasi-sinusoidal signals;

a displacement detection unit, for determining a frequency of said first and second sinusoidal signals, said frequency of said first sinusoidal signal representing a displacement of said pattern along said first dimension, said frequency of said second sinusoidal signal representing a direction of said displacement of said pattern along said first dimension.

2. The system of claim 1, wherein said pattern is one of a speckle pattern and a surface pattern.

3. The system of claim 1, further comprising:

a light source, for transmitting a light signal toward said surface.

4. The system of claim 3, wherein said light signal is coherent.

5. The system of claim 3, wherein said light signal is not coherent.

6. The system of claim 1;

wherein said displacement detection unit includes;

a first comparator for counting crossings of said first sinusoidal signal through a predetermined value; and

a second comparator for counting crossings of said second sinusoidal signals through a predetermined value.

7. The system of claim 6, wherein said first and second comparators utilize hysterisis when counting crossings through said predetermined value.

8. The system of claim 1, wherein said comb photodetector includes at least twelve of said elements.

9. The system of claim 1, further comprising:

a second detection system, positioned to detect a displacement along a second dimension, different from said first dimension.

10. The system of claim 9, wherein said second detection system comprises:

a second comb photodetector array, optically matched with said lens and said aperture, for receiving said focused light signal, said focused light signal having light and dark portions representing a second pattern caused by said light signal reflecting off of the surface, said second comb photodetector having a plurality of elements wherein every fourth element is connected to generate fifth, sixth, seventh, and eighth comb signals;

a second generation unit, for combining said fifth and sixth comb signals to generate a third quasi-sinusoidal signal, for combining said seventh and eighth comb signals to generate a fourth quasi-sinusoidal signal, wherein said third and fourth quasi-sinusoidal signals are quasi-sinusoidal signals;

a second displacement detection unit, for determining a frequency of said third and fourth sinusoidal signals, said frequency of said third sinusoidal signal representing a displacement of said second pattern along said second dimension, said frequency of said fourth sinusoidal signal representing a direction of said displacement of said pattern along said second dimension.

11. The system of claim 10, wherein said first and second patterns are the same.

12. An method for detecting movement of a pattern across a photodetector array, comprising the steps of:

receiving a light signal at the photodetector array, said light signal reflected off of a surface and passing though an aperture and a lens, said photodetector array optically matched with said lens and said aperture, said light signal having light and dark portions representing a pattern caused by said light signal reflecting off of the surface said photodetector array having first, second, third, fourth, fifth, sixth, seventh, and eighth elements;

combining a signal from said first and fifth elements to generate a first comb signal;

combining a signal from said second and sixth elements to generate a second comb signal;

combining a signal from said third and seventh elements to generate a third comb signal;

combining a signal from said fourth and eighth elements to generate a fourth comb signal;

combining said first and second comb signals to generate a first quasi-sinusoidal signal;

combining said third and fourth comb signals to generate a second quasi-sinusoidal signal, wherein said first and second quasi-sinusoidal signals are analog quasi-sinusoidal signals; and

determining a frequency of said first and second sinusoidal signals, said frequency of said first sinusoidal signal representing a displacement of said pattern along a first dimension, said frequency of said second sinusoidal signal representing a direction of said displacement of said pattern along said first dimension.

13. The method of claim 12, wherein said pattern is one of a speckle pattern and a surface pattern.

14. The method of claim 12, further comprising the step of:

transmitting a coherent light signal toward said surface.

15. The method of claim 12, further comprising the step of:

transmitting a non-coherent light signal toward said surface.

16. The method of claim 12, wherein said determining step includes the steps of:

counting crossings of said first sinusoidal signal through a predetermined value; and

counting crossings of said second sinusoidal signals through a predetermined value.

17. The method of claim 12, wherein said comb photodetector includes at least twelve of said elements.

18. The method of claim 12, further comprising the step of:

detecting a displacement along a second dimension, different from said first dimension, comprising the steps of;

receiving said light signal at a second photodetector array, said second photodetector array optically matched with said lens and said aperture, said light signal having light and dark portions representing a second pattern caused by said light signal reflecting off of the surface said second photodetector array having a plurality of elements;

combining a signal from every fourth element of said second photodetector array to generate fifth, sixth, seventh, and eighth comb signals;

combining said fifth and sixth comb signals to generate a third quasi-sinusoidal signal;

combining said seventh and eighth comb signals to generate a fourth quasi-sinusoidal signal, wherein said third and fourth quasi-sinusoidal signals are quasi-sinusoidal signals; and

determining a frequency of said third and fourth sinusoidal signals, said frequency of said third sinusoidal signal representing a displacement of said second pattern along said second dimension, said frequency of said fourth sinusoidal signal representing a direction of said displacement of said pattern along said second dimension.

19. The method of claim 18, wherein said first and second patterns are the same.

20. An method for detecting movement of a pattern across a photo detection means, comprising:

photo detection means, for receiving a light signal reflected off of a surface and passing through an aperture and a lens, said photodetector means optically matched with said lens and said aperture, said light signal having light and dark portions representing a pattern caused by said light signal reflecting off of a surface, said photodetector means having a plurality of elements;

first combining means, for combining a signal from said first and fifth elements to generate a first comb signal, for combining a signal from said second and sixth elements to generate a second comb signal, for combining a signal from said third and seventh elements to generate a third comb signal and for combining a signal from said fourth and eighth elements to generate a fourth comb signal;

second combining means, for combining said first and second comb signals to generate a first quasi-sinusoidal signal;

third combining means, for combining said third and fourth comb signals to generate a second quasi-sinusoidal signal, wherein said first and second quasi-sinusoidal signals arc quasi-sinusoidal signals; and

determining means, for determining a frequency of said first and second sinusoidal signals, said frequency of said first sinusoidal signal representing a displacement of said pattern along a first dimension, said frequency of said second sinusoidal signal representing a direction of said displacement of said pattern along said first dimension.