Firmware Methods and Devices for a Mutual Capacitance Touch Sensing Device

• US 20130321338A1
• Filed: 08/11/2013
• Published: 12/05/2013
• Est. Priority Date: 08/25/2009
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: Murphy, Thomas, Rathburn, Kevin, Leong, Keen Hun, Narasimhan, Sarangan
• Granted Patent: US 8,669,960 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 1/3215 Monitoring of peripheral devices
• CPC Class Codes: G06F 1/3262 Power saving in digitizer or tablet
• 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 2203/04108 Touchless 2D- digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface without distance measurement in the Z direction
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• 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: G06F 3/04883 for inputting data by handwriting, e.g. gesture or text

Abstract

Disclosed are various embodiments of methods and devices for operating a processor or host controller in a mutual capacitance sensing device. Methods and devices for sorting motion reports provided to a host controller or other processor in a mutual capacitance sensing device, reporting touch points to a host controller or other processor in a mutual capacitance sensing device, improving noise robustness and navigation performance in a mutual capacitance sensing device, determining a touch area of a user'"'"'s finger on a touch panel or touchpad of a mutual capacitance sensing device, and avoiding false wakeups and minimizing power consumption in a mutual capacitance sensing device having a touch panel or touchpad are described.

Claims

1. A method of determining a touch area of a user'"'"'s finger on a touch panel or touchpad in a mutual capacitance sensing device, comprising:

(a) determining, in a processor of the sensing device, which center sense cell in the touch panel or touchpad is generating a highest touch point signal level and determining such highest touch point signal level;

(b) determining touch point signal levels corresponding to cells adjacent to the center cell;

(c) for those adjacent cells where signal levels corresponding thereto meet or exceed a predetermined percentage of the highest touch point signal level, designating such cells as touch cells together with the center cell, and

(d) determining a touch area of the touch panel or touchpad on the basis of the touch cells.

2. The method of claim 1, wherein the adjacent cells are disposed vertically and horizontally to either side of the center cell.

3. The method of claim 2, further comprising determining a first value proportional to the number of horizontal touch cells having signal levels exceeding the threshold.

4. The method of claim 3, further comprising determining a second value proportional to the number of vertical touch cells having signal levels exceeding the threshold.

5. The method of claim 4, wherein the first and second values are scaled in respect of one another to produce a number representative of the touch area.