Sensing methods for touch sensing devices

• US 8,665,231 B2
• Filed: 11/29/2010
• Issued: 03/04/2014
• Est. Priority Date: 11/29/2010
• Status: Active Grant

• Current Assignee: InnoLux Corporation
• Original Assignee: InnoLux Corporation
• Inventors: Edwards, Martin John, Ayres, John Richard
• Primary Examiner(s): SHENG, TOM V
• Application Number:
  US12/955,118
• Publication Number:
  US 20120133594A1
• Time in Patent Office: 1,191 Days
• Field of Search: 345/173, 345/174, 178 1803- 1807
• US Class Current: 345/173
• 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 3/04182 Filtering of noise external to the device and not generated by digitiser components
• 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

Abstract

A sensing method for a touch sensing device is provided. In one embodiment, for one set of interlaced receiving electrode and transmitting electrodes of the touch sensing device, an integrator coupled to the receiving electrode is reset only one time. In another embodiment, for each group of sensing electrodes, an integrator coupled to the sensing electrodes is reset only one time. Accordingly, the rate at which the touch sensing array is sensed may be increased. Noise reduced by the process of resetting the integrator due to charge injection effects may be decreased.

Claims

1. A sensing method for a touch sensing device which comprises a touch sensing array and an integrator, wherein the touch sensing array comprises a plurality of first sensing electrodes disposed successively, and the sensing method comprises:

resetting the integrator;

measuring output signals corresponding to the first sensing electrodes, wherein the step of measuring the output signals corresponding to the first sensing electrodes comprises;

pre-charging a previous first sensing electrode among the first sensing electrodes to a first voltage;

connecting the previous first sensing electrode to the integrator;

measuring an output voltage of the integrator to obtain a previous first integration value;

pre-charging a current first sensing electrode among the first sensing electrodes, to a second voltage;

connecting the current first sensing electrode to the integrator;

measuring the output voltage of the integrator to obtain a current first integration value; and

calculating the difference between the previous first integration value and the current first integration value to obtain the output signal corresponding to the current first sensing electrode; and

measuring the output voltage of the integrator to obtain a first reference value after the integrator is reset,

wherein the step of measuring output signals corresponding to the first sensing electrodes further comprising;

calculating the difference between the first reference value and the previous first integration value to obtain the output signal corresponding to the previous first sensing electrode.

2. The sensing method as claimed in claim 1, wherein relative to a virtual earth voltage of the integrator, polarities of the first voltage and the second voltage are inverse.

3. The sensing method as claimed in claim 1, wherein the previous first sensing electrode is the first one among the successively disposed first sensing electrodes.

4. The sensing method as claimed in claim 1, wherein the step of measuring the output signals corresponding to the first sensing electrodes further comprises:

determining whether there is a following first sensing electrode among the first sensing electrodes which is next to the current first sensing electrode;

if there is a following first sensing electrode, pre-charging the following first sensing electrode to the first voltage;

connecting the following first sensing electrode to the integrator;

measuring the output voltage of the integrator to obtain a following first integration value; and

calculating the difference between the current first integration value and the following first integration value to obtain the output signal corresponding to the following first sensing electrode.

5. The sensing method as claimed in claim 4, wherein in the step of measuring output signals corresponding to the first sensing electrodes, if there is no further first sensing electrode, the sensing method further comprises:

resetting the integrator again; and

measuring output signals corresponding to second electrodes of the touch sensing panel, wherein the second electrodes disposed successively and interlacing with the first electrodes,

wherein the step of measuring the output signals corresponding to the second sensing electrodes comprises;

pre-charging a previous second sensing electrode among the second sensing electrodes to one of the first and second voltages;

connecting the previous second sensing electrode to the integrator;

measuring the output voltage of the integrator to obtain a previous second integration value;

pre-charging a current second sensing electrode among the second sensing electrodes to the other of the first and second voltages;

connecting the current second sensing electrode to the integrator;

measuring the output voltage of the integrator to obtain a current second integration value; and

calculating the difference between the previous second integration value and the current second integration value to obtain the output signal corresponding to the current second sensing electrode.

6. The sensing method as claimed in claim 5, wherein the step of measuring the output signals corresponding to the second sensing electrodes further comprises:

determining whether there is a following second sensing electrode among the second sensing;

if there is a following second sensing electrode, pre-charging the following second sensing electrode to the one of the first and second voltages which the previous second sensing electrode is pre-charged to;

connecting the following second sensing electrode to the integrator;

measuring the output voltage of the integrator to obtain a following second integration value; and

calculating the difference between the current second integration value and the following second integration value to obtain the output signal corresponding to the following second sensing electrode.

7. The sensing method as claimed in claim 1, wherein when an object touches the touch sensing device, a location of the object on the touch sensing array can be detected according to the output signals.

8. The measurement method as claimed in claim 1, wherein the second voltage is different from the first voltage or the second voltage is the same with the first voltage.

9. A sensing method for a touch sensing device which comprises a touch sensing array and an integrator, wherein the touch sensing array comprises a plurality of first sensing electrodes disposed successively, and the sensing method comprises:

resetting the integrator;

measuring output signals corresponding to the first sensing electrodes, wherein the step of measuring the output signals corresponding to the first sensing electrodes comprises;

pre-charging a previous first sensing electrode among the first sensing electrodes to a first voltage;

connecting the previous first sensing electrode to the integrator;

measuring an output voltage of the integrator to obtain a previous first integration value;

pre-charging a current first sensing electrode among the first sensing electrodes, to a second voltage;

connecting the current first sensing electrode to the integrator;

measuring the output voltage of the integrator to obtain a current first integration value; and

calculating the difference between the previous first integration value and the current first integration value to obtain the output signal corresponding to the current first sensing electrode,

wherein the step of measuring the output signals corresponding to the first sensing electrodes further comprises;

determining whether there is a following first sensing electrode among the first sensing electrodes which is next to the current first sensing electrode;

if there is a following first sensing electrode, pre-charging the following first sensing electrode to the first voltage;

connecting the following first sensing electrode to the integrator;

measuring the output voltage of the integrator to obtain a following first integration value; and

calculating the difference between the current first integration value and the following first integration value to obtain the output signal corresponding to the following first sensing electrode,

wherein in the step of measuring output signals corresponding to the first sensing electrodes, if there is no further first sensing electrode, the sensing method further comprises;

resetting the integrator again; and

measuring output signals corresponding to second electrodes of the touch sensing panel, wherein the second electrodes disposed successively and interlacing with the first electrodes,

wherein the step of measuring the output signals corresponding to the second sensing electrodes comprises;

pre-charging a previous second sensing electrode among the second sensing electrodes to one of the first and second voltages;

connecting the previous second sensing electrode to the integrator;

measuring the output voltage of the integrator to obtain a previous second integration value;

pre-charging a current second sensing electrode among the second sensing electrodes to the other of the first and second voltages;

connecting the current second sensing electrode to the integrator;

measuring the output voltage of the integrator to obtain a current second integration value; and

calculating the difference between the previous second integration value and the current second integration value to obtain the output signal corresponding to the current second sensing electrode,

wherein the sensing method further comprises;

after the step of resetting the integrator again, measuring the output voltage of the integrator to obtain a second reference value,

wherein the step of measuring output signals corresponding to the second sensing electrodes further comprises;

calculating the difference between the second reference value and the previous second integration value to obtain the output signal corresponding to the previous second sensing electrode.