Capacitive sensing device and capacitive sensing method

• US 10,048,813 B2
• Filed: 05/04/2015
• Issued: 08/14/2018
• Est. Priority Date: 12/19/2014
• Status: Active Grant

• Current Assignee: Imagination Broadway Ltd., Salt International Corp.
• Original Assignee: Imagination Broadway Ltd., Salt International Corp.
• Inventors: Lee, Shang-Li
• Primary Examiner(s): Chatly, Amit
• Application Number:
  US14/702,894
• Publication Number:
  US 20160179285A1
• Time in Patent Office: 1,198 Days
• Field of Search: 345173-178
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• 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 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 5/003 Details of a display terminal, the details relating to the control arrangement of the display terminal and to the interfaces thereto specific for a CRT G09G1/165; for a flat panel G09G3/2092

Abstract

A capacitive sensing method includes detecting present measured values of plural reference points selected from plural sensing points, generating a present difference value according to the present measured values of the reference points and one or more reference measured values, obtaining a selected adjustment factor according to a relation setting and the present difference value, detecting present measured values of the sensing points, generating plural position signals of the sensing points according to the present difference values of the sensing points, adjusting the position signals according to the selected adjustment factor, and controlling the output of the adjusted position signals according to a reference signal. The sensing points are defined by electrodes intersected with one another and configured to form an array. The reference points are located at the periphery of the array. The relation setting is the relationship between signal difference values and adjustment factors.

Claims

1. A capacitive sensing method, comprising:

detecting present measured values of a plurality of reference points selected from a plurality of sensing points, wherein the sensing points are defined by electrodes intersected with one another and the sensing points are configured to form an array, and wherein the reference points are located at the periphery of the array;

generating a present difference value according to the present measured values of the reference points and at least one reference measured value;

obtaining a selected adjustment factor according to a relation setting and the present difference value, wherein the relation setting is the relationship between signal difference values and adjustment factors;

detecting present measured values of the sensing points;

generating a plurality of position signals of the sensing points according to the present measured values of the sensing points;

adjusting the position signals according to the selected adjustment factor;

controlling the output of the adjusted position signals according to a reference signal; and

adjusting a detecting frequency of the present measured values of the reference points according to comparison of the present difference value and a first threshold.

2. The capacitive sensing method according to claim 1, wherein the step of detecting present measured values of a plurality of reference points selected from a plurality of sensing points further comprises:

driving at least one electrode located at a first side of the array and at least one electrode located at a second side of the array from the electrodes, wherein the first side is opposite to the second side; and

measuring at least one electrode located at a third side of the array and at least one electrode located at a fourth side of the array from the electrodes to obtain the present measured values of the reference points, wherein the third side is opposite to the fourth side.

3. The capacitive sensing method according to claim 1, wherein the step of detecting present measured values of a plurality of reference points selected from a plurality of sensing points further comprises:

driving and measuring at least one electrode located at at least one side of the array to obtain the present measured values of the reference points.

4. The capacitive sensing method according to claim 1, wherein the electrodes comprise a plurality of first electrodes and a plurality of second electrodes intersected with the first electrodes, and wherein the step of detecting present measured values of a plurality of reference points selected from a plurality of sensing points further comprises:

driving at least one of the first electrodes located at a first side of the array and at least one of the first electrodes located at a second side of the array, wherein the first side is opposite to the second side; and

measuring a number of the second electrodes to obtain the present measured values of the reference points.

5. The capacitive sensing method according to claim 4, wherein any two of the measured second electrodes are spaced by at least one unmeasured second electrode.

6. The capacitive sensing method according to claim 1, wherein the electrodes comprise a plurality of first electrodes and a plurality of second electrodes intersected with the first electrodes, and wherein the step of detecting present measured values of a plurality of reference points selected from a plurality of sensing points further comprises:

driving at least one of the first electrodes located at a first side of the array and at least one of the first electrodes located at a second side of the array, wherein the first side is opposite to the second side;

measuring at least one of the second electrodes to obtain present measured values of some of the reference points;

driving at least one of the second electrodes located at a third side of the array and a least one of the second electrodes located at a fourth side, wherein the third side is opposite to the fourth side; and

measuring at least one of the first electrodes to obtain present measured values of the rest reference points.

7. The capacitive sensing method according to claim 6, wherein any two of the measured first electrodes is spaced by at least one unmeasured first electrode, and wherein any two of the measured second electrodes is spaced by at least one unmeasured second electrode.

8. The capacitive sensing method according to claim 1, wherein the array is divided into a sensing area and an invalid area located at the periphery of the sensing area, and the reference points are located in the invalid area.

9. The capacitive sensing method according to claim 1, wherein the step of adjusting the detecting frequency of the present measured values of the reference points according to comparison of the present difference value and the first threshold comprises:

comparing the present difference value with the first threshold;

increasing the detecting frequency of the present measured values of the reference points when the present difference value is greater than the first threshold.

10. The capacitive sensing method according to claim 1, wherein the step of adjusting the detecting frequency of the present measured values of the reference points according to comparison of the present difference value and the first threshold comprises:

comparing the present difference value with the first threshold;

increasing the detecting frequency of the present measured values of the reference points and reset a count value when the present difference value is greater than the first threshold;

accumulating the count value when the present difference value is not greater than the first threshold;

decreasing the detecting frequency of the present measured values of the reference points and reset the count value when the count value is greater or equal to a predetermined value; and

retaining the same detecting frequency of the present measured values of the reference points when the count value is not reached to the predetermined value.