Touch pad for handheld device

• US 8,552,990 B2
• Filed: 08/01/2007
• Issued: 10/08/2013
• Est. Priority Date: 11/25/2003
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Marriott, Greg, Bar-Nahum, Guy, Bollinger, Steven
• Primary Examiner(s): Liang, Regina
• Application Number:
  US11/882,422
• Publication Number:
  US 20080012837A1
• Time in Patent Office: 2,260 Days
• Field of Search: 345173-179, 178 1801- 1811
• US Class Current: 345/173
• 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 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/04886 by partitioning the display area of the touch-screen or the surface of the digitising tablet into independently controllable areas, e.g. virtual keyboards or menus

Abstract

A touch pad system is disclosed. The system includes mapping the touch pad into native sensor coordinates. The system also includes producing native values of the native sensor coordinates when events occur on the touch pad. The system further includes filtering the native values of the native sensor coordinates based on the type of events that occur on the touch pad. The system additionally includes generating a control signal based on the native values of the native sensor coordinates when a desired event occurs on the touch pad.

Claims

1. A method comprising:

identifying a current object location relative to a touch surface,

determining an amount of movement of an object relative to the touch surface by calculating a difference between the current object location and a prior object location,

converting the current object location into a logical device unit when the calculated amount of movement is greater than or equal to a threshold value, and

filtering the calculated amount of movement when the calculated amount of movement is less than the threshold value so that the current object location is unaffected by the calculated amount of movement.

2. The method of claim 1, wherein the touch surface is circular.

3. The method of claim 2, wherein the touch surface is divided into a plurality of logical device units distributed around the touch surface in a clock-like manner.

4. The method of claim 1, wherein the logical device unit corresponds to a button function.

5. The method of claim 1, wherein the logical device unit corresponds to a movement direction on a display screen.

6. The method of claim 1, comprising implementing one or more functions on a media player based on the logical device unit.

7. The method of claim 1, wherein the threshold is determined by the following equation:

threshold (T)=C*(native sensor resolution of the touch surface/logical device resolution of the touch surface),

wherein the native sensor resolution represents the maximum number of different object locations detectable by sensors associated with the touch surface, the logical device resolution represents the number of logical device units associated with the touch surface, and C represents the width border area between clusters of sensors associated with the touch surface that define one logical device unit.

8. The method of claim 7, wherein C has a value between 0 and 0.5.

9. The method of claim 1, comprising storing the current object location for subsequent processing, the current user object location acting as the last object location in subsequent processing.

10. The method of claim 1, comprising generating a message for a host device, the message including the logical device unit, the logical device unit being used by the host device to move a control object in a specified manner.

11. A touch pad assembly, comprising:

a touch pad comprising one or more sensors configured to detect a current location and a prior location, and

a controller configured to (i) determine an amount of movement of an object relative to the touch pad by calculating a difference between the current location and the prior location, (ii) output the current location to a host device when the calculated amount of movement is greater than or equal to a threshold value, and (iii) filter the calculated amount of movement when the calculated amount of movement is less than the threshold value so that the current object location is unaffected by the calculated amount of movement.

12. The touch pad assembly of claim 11, wherein the controller is configured to output the current location to a host device by converting the current object location into a logical device unit and outputting the logical device unit to the host device.

13. The touch pad assembly of claim 12, wherein the touch pad is divided into a plurality of logical device units distributed around the touch pad in a clock-like manner.

14. The touch pad assembly of claim 13, wherein the touch pad is circular.

15. The touch pad assembly of claim 12, wherein the logical device unit corresponds to a movement direction on a display screen.

16. A method comprising:

mapping a touch pad into native sensor coordinates,

producing a native value associated with a native sensor coordinate when at least one of several different types of events occur on the touch pad,

filtering the native value based on the type of event,

generating a control signal based on the native value when a desired event occurs on the touch pad,

wherein the step of filtering comprises determining whether the native value is associated with a noise event or an actual event, filtering a noise event and passing an actual event to a host device, thereby reducing or preventing noise events from reaching the host device.

17. The method as recited in claim 16, wherein the control signal includes the native value if it is determined that the event is an actual event.

18. The method as recited in claim 16, comprising:

adjusting the native value into a new value if it is determined that the event is an actual event, and

including the new value in the control signal.

19. The method as recited in claim 18, wherein the new value and the native value are described using identical units.

20. The method as recited in claim 18, wherein the new value and the native value are described using different units.