Sensing method for a capacitive touch system

• US 8,350,824 B2
• Filed: 03/31/2009
• Issued: 01/08/2013
• Est. Priority Date: 04/02/2008
• Status: Active Grant

• Current Assignee: Elan Microelectronics Corporation
• Original Assignee: Elan Microelectronics Corporation
• Inventors: Hung, Tse-Lun, Huang, Jung-Shou, Tsai, Hsin-Shieh
• Primary Examiner(s): Boddie, William L
• Assistant Examiner(s): THOMPSON, CHRISTOPHER D
• Application Number:
  US12/385,095
• Publication Number:
  US 20090251429A1
• Time in Patent Office: 1,379 Days
• Field of Search: None
• US Class Current: 345/174
• CPC Class Codes: G06F 3/04164 Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/044 by capacitive means

Abstract

A capacitive touch system uses at least two touch integrated circuits to simultaneously scan a touch panel, each of the touch integrated circuits only for scanning a portion of the traces of the touch panel. Therefore, the capacitive touch system can maintain a good frame rate, even the touch panel is a large scale touch panel. Sensing methods are provided to determine a sensed value for a boundary trace which is the last one of the traces connected to a first touch integrated circuit and prior to the first one of the traces connected to a second touch integrated circuit.

Claims

1. A sensing method for a capacitive touch system including a touch panel having a plurality of first traces and a plurality of second traces, of which the first one of the plurality of second traces is next to the last one of the plurality of first traces, the sensing method comprising the steps of:

(A) scanning the plurality of first traces by a first touch integrated circuit and the plurality of second traces by a second touch integrated circuit, each of the plurality of first traces except the last one thereof providing a first ADC value, each of the plurality of second traces providing a second ADC value;

(B) selecting at least one from the first ADC values and at least one from the second ADC values; and

(C) calculating with the selected ADC values to determine a sensed value for the last one of the plurality of first traces.

2. The sensing method of claim 1, wherein the step C comprises averaging the selected ADC values to obtain an average thereof as the sensed value for the last one of the plurality of first traces.

3. The sensing method of claim 1, wherein the step C comprises low-pass filtering the selected ADC values to determine the sensed value for the last one of the plurality of first traces.