Force-based input device

• US 20060279553A1
• Filed: 04/11/2006
• Published: 12/14/2006
• Est. Priority Date: 06/10/2005
• Status: Active Grant

• Current Assignee: QSI Incorporated (Quanta Services Incorporated)
• Original Assignee: QSI Incorporated (Quanta Services Incorporated)
• Inventors: Mullins, James R., Elwell, James K., Soss, David A.
• Granted Patent: US 7,903,090 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/04142 the force sensing means being located peripherally, e.g. disposed at the corners or at the side of a touch sensing plate

Abstract

Disclosed is an input device comprising (a) a base support, having a periphery and a plurality of apertures formed therein to define a circumscribed or circumscribing input pad configured to displace under the applied force; (b) a plurality of isolated beam segments, defined by the plurality of apertures, and operable to receive resultant forces distributed to the isolated beam segments by the displacement of the input pad; (c) at least two sensors, disposed along each isolated beam segment, and configured to measure the forces transmitted from the input pad to the periphery and to output a signal corresponding to the applied force. One or more processing means operable with the plurality of sensors may be utilized to receive the signal and to determine at least one of a location and/or magnitude of the applied force acting on the input pad.

Claims

1. An input device suitable for determining location and magnitude of an applied force, comprising:

a) a base support having a periphery and a plurality of apertures formed near the periphery to define an input pad configured to displace under the applied force;

b) a plurality of isolated beam segments defined by the plurality of apertures and operable to receive resultant forces distributed to the isolated beam segments by the displacement of the input pad; and

c) at least one sensor operable with each isolated beam segment to measure the strain within the respective isolated beam segment occurring as a result of various stresses being created by the displacement of the input pad in response to the applied force and transmitted to the periphery, the at least one sensor also being configured to output a signal corresponding to the applied force and the measured strain to be used to determine a location of the applied force.

2. The input device of claim 1, further comprising processing means operable with the at least one sensor to receive the signal and to determine at least one of the location and a magnitude of the applied force acting on the input pad.

3. The input device of claim 1, wherein the plurality of apertures comprise elongated slots extending through the base support.

4. The input device of claim 1, wherein the plurality of apertures comprise a geometric configuration selected from a linear configuration, a curved configuration, a spline configuration, and any combination of these.

5. The input device of claim 1, wherein the at least one sensor comprises a strain gauge associated with each isolated beam segment that functions to measure a strain differential across the isolate beam segment.

6. The input device of claim 1, wherein each of the at least one sensors located on each of the isolated beam segments are located in a common sensor plane with respect to one another.

7. The input device of claim 6, wherein the sensor plane is parallel to a plane of the input pad.

8. The input device of claim 1, wherein the input pad further comprises:

a) a large central aperture, disposed in the base support; and

b) a removable force panel, disposed in the large aperture, configured to receive the applied force, and transmit resultant forces to the base support.

9. The input device of claim 1, wherein the plurality of apertures are through-slots in the base support, the apertures being configured to control the path of forces that are transmitted from the input pad to the periphery of the base support.

10. The input device of claim 1, wherein the plurality of isolated beam segments further comprise:

an inner juncture, formed with the input pad;

a periphery juncture, formed with the periphery of the base support, wherein the inner juncture and periphery juncture function to concentrate the stresses induced on the base support from the applied force within the isolated beam segments by deflecting in opposite directions.

11. The input device of claim 1, wherein the base support comprises a first side and a second side, each configured to receive an applied force thereon.

12. The input device of claim 1, wherein the base support comprises a geometry selected from the group consisting of a polygonal geometry, an arbitrary geometry, and any combination of these.

13. The input device of claim 1, wherein the at least one sensor is selected from the group consisting of a strain gauge, a capacitance sensor, a liquid level sensor, piezoelectric transducers, and a laser sensor.

14. The input device of claim 1, wherein the at least one sensor comprises a strain gauge located along each of the isolated beam segments, the strain gauges being configured to measure a strain differential across the beam segment upon deflection.

15. The input device of claim 1, wherein the plurality of apertures define a rectangular input pad and isolated beam segments near corners of, and parallel to, sides of the input pad.

16. The input device of claim 1, wherein the plurality of apertures define a rectangular input pad and isolated beam segments near corners of, and at an oblique angle to, sides of the input pad.

17. The input device of claim 1, wherein the plurality of apertures define a rectangular input pad and isolated beam segments near a center of, and parallel to, sides of the input pad.

18. The input device of claim 1, wherein the plurality of apertures extend parallel to sides of the input pad between two sensors and orthogonally to sides of the input pad at the two sensors.

19. The input device of claim 1, wherein the plurality of apertures comprise a change in width that corresponds to each of the isolated beam segments.

20. The input device of claim 1, wherein the plurality of apertures define a rectangular input pad including two adjacent isolated beam segments near corners of the input pad.

21. The input device of claim 1, wherein the plurality of apertures comprise a stress concentrating notch that corresponds to each of the at least one sensors located on each of the isolated beam segments.

22. The input device of claim 1, wherein each of the isolated beam segments has a subsurface hole extending at least partially through the isolated beam segment near each of the at least one sensors.

23. The input device of claim 1, wherein the isolated beam segments further comprise at least two holes associated therewith, each hole located on an opposite side of the isolated beam segment and being configured to concentrate stresses in the isolated beam segment, wherein each hole extends into the isolated beam segment toward the at least one sensor.

24. The input device of claim 1, further comprising two parallel sensors disposed at a first end of each isolated beam segment, and two parallel sensors disposed at a second, opposite end of each isolated beam segment.

25. The input device of claim 1, further comprising sealing means configured to seal and protect the touch pad and its component parts from foreign objects, moisture, and debris.

26. An input device configured to receive an applied force, the input device comprising:

a) a first structural element supported in a fixed position;

b) a second structural element operable with the first structural element, and dynamically supported to be movable with respect to the first structural element to define an input pad configured to displace under the applied force;

c) a plurality of isolated beam segments joining said first and second structural elements, said isolated beam segments being operable to transfer forces between the first and second structural elements, and to receive resultant forces distributed to the isolated beam segments by the displacement of the input pad; and

d) at least one sensor operable with each isolated beam segment to measure the strain within the respective isolated beam segment occurring as a result of various stresses transmitted to the isolated beam segments by the displacement of the input pad in response to the applied force, each of the sensors also being configured to output a signal corresponding to the applied force and the measured strain to be used to determine a location of the applied force.

27. The input device of claim 26, wherein the first structural element comprises a outer mounting surface, and the second structural element comprises the input pad as circumscribed by the outer mounting surface and an inner mounting surface.

28. The input device of claim 26, wherein the first structural element comprises an inner mounting surface, and the second structural element comprises the input pad as positioned about the periphery of the input device, wherein an outer mounting surface and the inner mounting surface are circumscribed by the input pad.

29. An input device configured to receive an applied force, the input device comprising:

a) a base support having a periphery and a plurality of grooves formed at the periphery and extending only partially through the base support, the grooves being configured to define an input pad movable with respect to the base support, the input pad being configured to displace under the applied force;

b) a plurality of isolated beam segments defined by the plurality of grooves and operable to receive resultant forces distributed to the isolated beam segments by the displacement of the input pad; and

c) at least one sensor operable with each isolated beam segment to measure the strain within the respective isolated beam segment occurring as a result of various stresses being created by the displacement of the input pad in response to the applied force and transmitted to the periphery, the at least one sensor also being configured to output a signal corresponding to the applied force and the measured strain to be used to determine a location of the applied force.

30. A method for making a touch pad device, comprising the steps of:

a) providing a base support capable of receiving an applied force;

b) forming apertures through peripheral locations on the base support to define an input pad and a plurality of isolated beam segments operable to receive resultant forces distributed to the isolated beam segments by the displacement of the input pad;

c) providing a plurality of sensors along each of the isolated beam segments to measure the strain within the plurality of isolated beam segments occurring as a result of various stresses created by the displacement of the input pad and transmitted to the peripheral locations in response to the applied force, and to output a signal corresponding to the applied force to be used to determine the location of said applied force.

31. The method of claim 30, further comprising providing processing means for processing the output signal from the sensors to determine at least one of the location and a magnitude of the applied force.

32. A method for determining at least one of location and magnitude of a force applied to an input pad, the method comprising:

a) providing a base support having a periphery and a plurality of isolated beam segments formed by a plurality of apertures at the periphery that define an input pad configured to displace in response to the force, the isolated beam segments having located thereon at least one sensor;

b) measuring the strain within the plurality of isolated beam segments, which strain occurs as a result of various stresses created by the displacement of the input pad in response to the force as applied thereto;

c) generating an output signal from each of the sensors, the output signal corresponding to the measured strain; and

d) processing the output signal from the at least two sensors to determine the location of the force applied to the input pad.

33. The method of claim 32, further comprising processing the output signal from the at least two sensors to determine the magnitude of the force applied to the input pad

34. A method for determining at least one of location and magnitude of a force applied to an input pad, the method comprising:

a) providing a first structural element;

b) providing a second structural element operable with the first structural element to define a plurality of apertures, and dynamically supporting one of said first and second structural elements with respect to the other, which is fixedly supported, to define an input pad configured to displace under the applied force, the plurality of apertures defining a plurality of isolated beam segments operable to transfer forces between the first and second structural elements, and to receive resultant forces distributed to the isolated beam segments by the displacement of the input pad;

c) measuring the strain within the plurality of isolated beam segments, which strain occurs as a result of various stresses transmitted to the isolated beam segments by the displacement of the input pad in response to the applied force;

d) generating an output signal corresponding to the measured strain; and

e) processing the output signal to determine the location of the force applied to the input pad.

35. The method of claim 34, further comprising processing the output signal to determine the magnitude of the force applied to the input pad.