POINTING DEVICES

• US 20110057906A1
• Filed: 09/03/2010
• Published: 03/10/2011
• Est. Priority Date: 09/09/2009
• Status: Active Grant

• Current Assignee: STMicroelectronics Limited (STMicroelectronics NV)
• Original Assignee: STMicroelectronics Limited (STMicroelectronics NV)
• Inventors: Raynor, Jeffrey, Laflaquiere, Arnaud
• Granted Patent: US 8,723,816 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G06F 2203/0339 Touch strips, e.g. orthogonal touch strips to control cursor movement or scrolling; single touch strip to adjust parameter or to implement a row of soft keys
• CPC Class Codes: G06F 3/03547 Touch pads, in which fingers can move on a surface

Abstract

A touch pad uses a plurality of optical mouse type sensors. The sensors are optimized for detection of motion along the predominant direction of a user'"'"'s finger as the finger is moved around the touch pad. A first one of the sensors functions to optically sense motion in a first direction, while a second one of the sensors functions to optically sense motion in a second, different, direction. The first and second directions are oriented a closed, for example, circular, path.

Claims

1. A touch pad pointing device comprising:

a mousing surface defining a closed path for a user pointer;

at least one optical mouse sensor oriented in a first direction;

at least one optical mouse sensor oriented in a second, different, direction; and

a detector provided to detect direction of motion of a user pointer along the closed path and to detect speed of motion on the basis of a motion detection output from the at least one optical mouse sensor oriented in the first direction and the at least one optical mouse sensor oriented in the second direction.

2. The touch pad pointing device of claim 1, wherein the closed path is in the shape of a circle.

3. The touch pad pointing device of claim 1, wherein at least four sensors are provided, defining at least four angularly equidistant touch zones.

4. The touch pad pointing device of claim 1, wherein the sensors and the mousing surface operate to provide frustrated total internal reflection.

5. The touch pad pointing device of claim 3, wherein each of the sensors has the same address and a system controller is provided that has four separate ports.

6. The touch pad pointing device of claim 5, wherein the ports are I2C or SPI interfaces.

7. The touch pad pointing device of claim 1, wherein the sensors have the same address and a system controller has a single port and a bus multiplexer.

8. The touch pad pointing device of claim 1, wherein each of the sensors has different or programmable addresses and can share the same bus.

9. The touch pad pointing device of claim 1, wherein the detector comprises an optical proximity detector configured to detect both direction of motion and speed of motion.

10. The touch pad pointing device of claim 1, wherein at least one of the sensors comprises a photodetector with a linear array of pixels.

11. The touch pad pointing device of claim 1, wherein reset periods of at least two of the sensors are offset, such that a first sensor is held in reset during an entire time period while a radiation source is illuminating a second sensor.

12. The touch pad pointing device of claim 11, wherein the first sensor is held in reset during an entire integration time period of the second sensor.

13. The touch pad pointing device of claim 11, wherein the first and second sensors are neighbors in the array.

14. The touch pad pointing device of claim 11, wherein the offset timing is carried out between two groups of sensors.

15. The touch pad pointing device of claim 1, wherein touch zones for each sensor are elongated in a direction of a predominant direction of motion of a user pointer for each sensor.

16. The touch pad pointing device of claim 1, wherein the sensor arrays have a non-square aspect ratio.

17. The touch pad pointing device of claim 1, wherein individual pixels have a non-square aspect ratio.

18. A method of sensing motion of a user pointer on a touch pad pointing device comprising:

optically sensing motion in a first direction at a first point along a closed path;

optically sensing motion in a second, different, direction at a second, different, point along the closed path;

wherein the closed path is defined by a mousing surface of the touch pad pointing device;

detecting a direction of motion of a user pointer along the closed path on the basis of a motion detection output from said at least one optical mouse sensor oriented in the first direction and said at least one optical mouse sensor oriented in the second direction; and

detecting the speed of motion of the user pointer along the closed path on the basis of a motion detection output from said at least one optical mouse sensor oriented in the first direction and said at least one optical mouse sensor oriented in the second direction.

19. The method of claim 18, wherein the closed path is in the shape of a circle.

20. The method of claim 18, further comprising optically sensing motion in at least four different directions at different detection points along the closed path, the detection points being angularly equidistant.

21. The method of claim 18, wherein the step of optically sensing motion comprises detecting a frustrated total internal reflection signal.

22. The method of claim 18, wherein the detection is carried out using an optical proximity detector.

23. The method of claim 18, wherein reset periods of at least two of the sensors are offset, such that a first sensor is held in reset during an entire time period while a radiation source is illuminating a second sensor.

24. The method of claim 23, wherein the first sensor is held in reset during an entire integration time period of the second sensor.

25. The method of claim 24, wherein the offset timing is carried out between two groups of sensors.

26. A touch pad pointing device, comprising:

a mousing surface defining a closed curved path for a user pointer;

a first optical frustrated total internal reflection sensor having a movement detection direction oriented in a first direction tangential to the closed curved path and positioned at a first location along the closed path;

a second optical frustrated total internal reflection sensor having a movement detection direction oriented in a second direction tangential to the closed path and positioned at a second, different, location along the closed curved path.

27. The device of claim 26 wherein each optical frustrated total internal reflection sensor comprising a plurality of sensor pixels arranged in an array.

28. The device of claim 27 wherein means are provided to detect the direction of motion of the user pointer along the closed curved path and/or to detect the speed of motion of the user pointer along the closed curved path, on the basis of a motion detection output from each of the optical frustrated total internal reflection sensors.

29. The device of claim 28, wherein the means to detect comprises an optical proximity detector.