TOUCH PAD WITH FORCE SENSORS AND ACTUATOR FEEDBACK

• US 20110141052A1
• Filed: 12/10/2009
• Published: 06/16/2011
• Est. Priority Date: 12/10/2009
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Kessler, Patrick, Coelho, Marcelo H., Puskarich, Paul, Cieplinski, Avi, Kerr, Duncan, Bernstein, Jeffrey Traer, Pance, Aleksandar, Degner, Brett W.
• Granted Patent: US 8,633,916 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: A63B 2022/0092 for training agility or co-ordination of movements
• CPC Class Codes: G06F 1/1613 for portable computers cooling arrangements therefor G06F1/203; constructional details or arrangements for pocket calculators, electronic agendas or books G06F15/0216; constructional details of portable telephone sets: with several bodies H04M1/0202
• CPC Class Codes: G06F 1/1662 Details related to the integrated keyboard
• CPC Class Codes: G06F 1/1692 the I/O peripheral being a secondary touch screen used as control interface, e.g. virtual buttons or sliders
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• CPC Class Codes: G06F 3/016 Input arrangements with force or tactile feedback as computer generated output to the user
• CPC Class Codes: G06F 3/0227 Cooperation and interconnection of the input arrangement with other functional units of a computer G06F3/023 - G06F3/037 take precedence
• CPC Class Codes: G06F 3/03547 Touch pads, in which fingers can move on a surface
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0414 using force sensing means to determine a position
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04

Abstract

Electronic devices may use touch pads that have touch sensor arrays, force sensors, and actuators for providing tactile feedback. A touch pad may be mounted in a computer housing. The touch pad may have a rectangular planar touch pad member that has a glass layer covered with ink and contains a capacitive touch sensor array. Force sensors may be mounted under each of the four corners of the rectangular planar touch pad member. The force sensors may be used to measure how much force is applied to the surface of the planar touch pad member by a user. Processed force sensor signals may indicate the presence of button activity such as press and release events. In response to detected button activity or other activity in the device, actuator drive signals may be generated for controlling the actuator. The user may supply settings to adjust signal processing and tactile feedback parameters.

Claims

1. A track pad that receives input from an external object, comprising:

a touch pad member having a touch pad sensor array that gathers touch sensor array signals indicative of a given location at which the external object has touched the touch pad member;

a plurality of force sensors each of which is connected to the touch pad member at a different location, wherein the force sensors produce force output signals indicative of how forcefully the external object is pressing on the touch pad member; and

an actuator that laterally actuates the touch pad member.

2. The track pad defined in claim 1 wherein the touch pad sensor array comprises a capacitive touch sensor having an array of capacitive electrodes.

3. The track pad defined in claim 2 wherein each of the plurality of force sensors comprises a piezoelectric force sensor and wherein the touch pad member is mounted at a fixed location within a computer housing by the plurality of force sensors.

4. The track pad defined in claim 1 wherein the actuator comprises at least one coil of wire, wherein the touch pad member is substantially planar and lies in a plane, and wherein the actuator imparts lateral in-plane movement to the touch pad member.

5. The track pad defined in claim 1 wherein the touch pad member is substantially planar and has edges and wherein actuator comprises a solenoid with a plunger that imparts movement to one of the edges.

6. The track pad defined in claim 1 wherein the touch pad member comprises a rigid substantially planar structure that has an edge and wherein the actuator is coupled to the edge and moves the touch pad member by imparting lateral in-plane force to the edge.

7. The track pad defined in claim 1, wherein the actuator comprise an electromagnetic actuator that is controlled by a drive signal, wherein the touch pad member comprises a rigid touch pad member that lies in a plane, wherein the touch pad member has left, right, rear, and front edges, wherein the left and right edges are shorter than the rear and front edges, wherein the actuator is coupled to a selected one of the left edge and the right edge, and wherein the actuator moves the touch pad member horizontally within the plane without moving the touch pad member vertically out of the plane.

8. The track pad defined in claim 7 wherein the touch pad member comprises a rigid rectangular member that is globally actuated by the actuator and wherein the plurality of force sensors comprises four force sensors each of which is located at a respective corner of the touch pad member and each of which produces a separate analog force output signal indicative of how forcefully the external object is pressing on the touch pad member.

9. The track pad defined in claim 8 further comprising flexible pads coupled to each of the four force sensors.

10. The track pad defined in claim 9 wherein the flexible pads comprise gel.

11. The track pad defined in claim 10 wherein the force sensors comprise piezoelectric force sensors.

12. An electronic device comprising:

storage and processing circuitry; and

a track pad coupled to the storage and processing circuitry, wherein the track pad has an active surface and a touch pad member that extends across substantially all of the active surface, a touch sensor array coupled to the touch pad member, force sensors coupled to the touch pad member that produce force sensor signals indicative of how forcefully an external object is pressing on the touch pad member, and an actuator coupled to the touch pad member that produces tactile feedback by moving the touch pad member in response to the force sensor signals, wherein the storage and processing circuitry is configured to use the touch sensor array to detect gesturing activity on the track pad and is configured to momentarily inhibit movement of the touch pad member by the actuator in response to detecting the gesturing activity.

13. The electronic device defined in claim 12 wherein the touch pad member has four edges and lies substantially in a plane and wherein the actuator is coupled to one of the edges and moves the touch pad member substantially within the plane.

14. The electronic device defined in claim 13 wherein the storage and processing circuitry comprises force signal processing circuitry that process the force sensor signals to produce press and release data indicative of when a user has pressed and released a finger contacting the touch pad member.

15. The electronic device defined in claim 14 wherein the force sensors comprise piezoelectric sensors.

16. The electronic device defined in claim 14 further comprising:

a plurality of flexible pads, each of the flexible pads being coupled to a respective one of the force sensors.

17. The electronic device defined in claim 16 further comprising:

housing structures, wherein the plurality of flexible pads are mounted to the housing structures.

18. The electronic device defined in claim 17 wherein the housing structures include a computer housing wall to which the flexible pads are attached.

19. The electronic device defined in claim 17 further comprising coupling structures coupled between the actuator and the touch pad member.

20. The electronic device defined in claim 19 wherein the coupling structures comprise an elongated metal member.

21. The electronic device defined in claim 20 wherein the elongated metal member has portions comprising a bend.

22. The electronic device defined in claim 19 wherein the coupling structures comprise a mechanical linkage.

23. The electronic device defined in claim 22 wherein the mechanical linkage comprises at least one member and at least one pivot about which the member rotates.

24. The electronic device defined in claim 12 wherein the storage and processing circuitry is configured to receive user-defined force signal processing settings.

25. The electronic device defined in claim 12 wherein the touch sensor array produces touch data and wherein the storage and processing circuitry is configured to receive first user-defined settings that control how the storage and processing circuitry processes the force sensor signals and is configured to receive second user-defined settings that control how the storage and processing circuitry processes the force sensor signals.

26. A method of operating a computer track pad that has a touch pad member with a touch sensor array, force sensors connected to the touch pad member, and an actuator, comprising:

with the touch sensor array, determining a location of an external object in contact with the touch pad member of the track pad;

with each of the force sensors, measuring how much force is applied to the touch pad member of the track pad with the external object; and

with the actuator, imparting global movement to the touch pad member of the track pad based at least partly on data gathered with the force sensors.

27. The method defined in claim 26 wherein the actuator is driven by actuator drive signals to impart the movement to the touch pad member of the track pad, the method further comprising:

gathering user-defined driver settings; and

when imparting movement to the touch pad member of the track pad, generating the actuator drive signals based at least partly on the user-defined driver settings.

28. The method defined in claim 27 wherein the user-defined driver settings include settings specifying use of asymmetric actuator drive signals having faster rise times than fall times.

29. The method defined in claim 27 wherein the user-defined driver settings include settings specifying use of asymmetric actuator drive signals having faster fall times than rise times.

30. The method defined in claim 29 wherein the user-defined driver settings further include settings specifying use of symmetric actuator drive signals having substantially equal rise and fall times.

31. The method defined in claim 29 wherein there are four of the force sensors each of which is located under a respective corner of the touch pad member of the track pad, wherein the force sensor signals comprise analog force sensor signals, and wherein measuring how much force is applied to the touch pad member of the track pad comprises:

gathering separate analog force sensor signals from each of the four force sensors; and

combining the analog force sensor signals that have been gathered.

32. The method defined in claim 31 wherein combining the analog force sensor signals comprises digitally averaging the analog force sensor signals.

33. A computer track pad system, comprising:

a rigid rectangular touch pad member that includes a capacitive touch sensor array and that has four corners;

four force sensors, each force sensor being coupled to a respective one of the four corners;

at least one actuator that is connected to an edge of the rigid rectangular touch pad member by a coupling member and that imparts movement to all of the rigid rectangular touch pad member in response to actuator drive signals; and

circuitry that processes touch sensor data from the capacitive touch sensor array and analog force data from the force sensors and that produces the actuator drive signals for the actuator based on the touch sensor data from the capacitive touch sensor array and based on the analog force data from the force sensors.

34. The computer track pad system defined in claim 33 wherein each of the four force sensors produces a corresponding analog force signal and wherein the circuitry is configured to process the analog force signals from the four force sensors to produce an average force signal.

35. The computer track pad system defined in claim 34 wherein the circuitry is configured to identify button press and button release activity by processing the average force signal and wherein the button press and button release activity is indicative of forces applied to the rigid rectangular touch member by a user.

36. The computer track pad system defined in claim 35 wherein the circuitry is configured to produce the corresponding actuator drive signals in response to identifying the button press and button release activity.

37. The computer track pad system defined in claim 36 wherein the circuitry is configured to inhibit production of the corresponding actuator drive signals in response to identifying the button press and button release activity when the circuitry detects simultaneous gesture activity with the capacitive touch sensor array.

38. The computer track pad system defined in claim 33 wherein the force sensors include polymer-metal composite force sensors.

39. The computer track pad system defined in claim 33 wherein the force sensors include material that exhibits a change in resistance when force is applied to the force sensors.

40. The computer track pad system defined in claim 33 wherein the force sensors include electrodes that exhibit capacitance changes when force is applied to the force sensors.

41. The computer track pad system defined in claim 33 wherein the force sensors include strain gauges.

42. The computer track pad system defined in claim 33 wherein the rigid rectangular touch pad member comprises:

a rectangular planar layer of glass; and

a layer of opaque ink covering at least one surface of the layer of glass that prevents light from passing through the layer of glass.