Capacitive touch screen

• US 8,754,868 B2
• Filed: 08/06/2013
• Issued: 06/17/2014
• Est. Priority Date: 12/30/2010
• Status: Active Grant

• Current Assignee: eGalax_eMPIA Technology Inc.
• Original Assignee: eGalax_eMPIA Technology Inc.
• Inventors: Chang, Chin-Fu
• Primary Examiner(s): CERULLO, LILIANA P
• Application Number:
  US13/960,109
• Publication Number:
  US 20130314376A1
• Time in Patent Office: 315 Days
• Field of Search: 345173-184, 178 1801- 2004
• US Class Current: 345/173
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 2203/04107 Shielding in digitiser, i.e. guard or shielding arrangements, mostly for capacitive touchscreens, e.g. driven shields, driven grounds
• CPC Class Codes: G06F 2203/04111 Cross over in capacitive digitiser, i.e. details of structures for connecting electrodes of the sensing pattern where the connections cross each other, e.g. bridge structures comprising an insulating layer, or vias through substrate
• 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 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• 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: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

The present invention provides a mutual capacitive multi-touch screen. The conductive strip pattern allows that, when a touch range of each external conductive object on the mutual capacitive multi-touch screen is larger than a predetermined condition, capacitive coupling between each external conductive object and first conductive strip is greater than capacitive coupling between each external conductive object and second conductive strip, such that the proportion of a driving signal flowing out of the first conductive strip via at least one first external conductive object in the external conductive objects and into the second conductive strip via at least one second external conductive object in the external conductive objects decreases as the number of second external conductive objects increases.

Claims

1. A detecting circuit, applied to a touch system including a touch panel and a display, wherein the touch panel includes a plurality of electrodes facing each other, and the electrodes including a plurality of first electrodes operatively provided with a driving signal during mutual capacitive detection and a plurality of second electrodes providing mutual capacitive coupling signals, wherein the second electrodes includes a first detecting electrode, a second detecting electrode and a third electrode parallelized continuously, and the detecting circuit executes the following operations:

detecting signals of the second electrodes to generate a plurality of differences comprising a first difference and a second difference, wherein the first difference is the difference between the signals of the first detecting electrode and the second detecting electrode, and the second difference is the difference between the signals of the second detecting electrode and the third detecting electrode,

wherein when the display updates frames during detection by the detecting circuit, the signals of the second electrodes comprises the mutual capacitive coupling signals and noises from the display, and the differences suppresses the noises.

2. The detecting circuit according to claim 1, wherein the second electrodes are capacitively coupled to the display, and the noises of the signals of the first detecting electrode, the second detecting electrode and the third detecting electrode are a first noise, a second noise and a third noise separately when the display updates frames during detection by the detecting circuit, wherein the values of the first noise and the second noise approximate to each other, and the values of the second noise and the third noise approximate to each other.

3. The detecting circuit according to claim 2, wherein the first difference is the difference between the mutual capacitive coupling signals of the first detecting electrode and the second detecting electrode after the first noise and the second noise cancel out when the detecting circuit generates the first difference by the subtraction between the signals of the first detecting electrode and the second electrode, and the second difference is the difference between the mutual capacitive coupling signals of the second detecting electrode and the third detecting electrode after the second noise and the third noise cancel out when the detecting circuit generates the second difference by the subtraction between the signals of the second detecting electrode and the third electrode, so as to suppress the noises from the display.

4. The detecting circuit according to claim 1, wherein the touch panel comprises a first insulating layer and a second insulating layer, wherein the first electrodes are located between the first insulating layer and the second insulating layer, and the second electrodes are located between the second insulating layer and the display.

5. The detecting circuit according to claim 1, wherein the area of the first electrodes outside of the intersecting area of the first electrodes and the second electrodes is larger than the area of the second electrodes outside of the intersecting area of the first electrodes and the second electrodes.

6. A touch system, comprising:

a display;

a touch panel, comprising a plurality of electrodes facing each other, and the electrodes including a plurality of first electrodes operatively provided with a driving signal during mutual capacitive detection and a plurality of second electrodes providing mutual capacitive coupling signals, wherein the second electrodes includes a first detecting electrode, a second detecting electrode and a third electrode parallelized continuously;

a detecting circuit, detecting signals of the second electrodes to generate a plurality of differences comprising a first difference and a second difference, wherein the first difference is the difference between the signals of the first detecting electrode and the second detecting electrode, and the second difference is the difference between the signals of the second detecting electrode and the third detecting electrode,

wherein when the display updates frames during detection by the detecting circuit, the signals of the second electrodes comprises the mutual capacitive coupling signals and the noises from the display, and the differences suppresses the noises.

7. The touch system according to claim 6, wherein the second electrodes are capacitively coupled to the display, and the noises of the signals of the first detecting electrode, the second detecting electrode and the third detecting electrode are a first noise, a second noise and a third noise separately when the display updates frames during detection by the detecting circuit, wherein the values of the first noise and the second noise approximate to each other, and the values of the second noise and the third noise approximate to each other.

8. The touch system according to claim 7, wherein the first difference is the difference between the mutual capacitive coupling signals of the first detecting electrode and the second detecting electrode after the first noise and the second noise cancel out when the detecting circuit generates the first difference by the subtraction between the signals of the first detecting electrode and the second electrode, and the second difference is the difference between the mutual capacitive coupling signals of the second detecting electrode and the third detecting electrode after the second noise and the third noise cancel out when the detecting circuit generates the second difference by the subtraction between the signals of the second detecting electrode and the third electrode, so as to suppress the noises from the display.

9. The touch system according to claim 6, wherein the touch panel comprises a first insulating layer and a second insulating layer, wherein the first electrodes are located between the first insulating layer and the second insulating layer, and the second electrodes are located between the second insulating layer and the display.

10. The touch system according to claim 6, wherein the area of the first electrodes outside of the intersecting area of the first electrodes and the second electrodes is larger than the area of the second electrodes outside of the intersecting area of the first electrodes and the second electrodes.

11. A detecting method, executed by a detecting circuit of a touch system which further comprises a touch panel and a display, wherein the touch panel includes a plurality of electrodes facing each other, and the electrodes including a plurality of first electrodes operatively provided with a driving signal during mutual capacitive detection and a plurality of second electrodes providing mutual capacitive coupling signals, wherein the second electrodes includes a first detecting electrode, a second detecting electrode and a third electrode parallelized continuously, and the detecting method comprises:

detecting signals of the second electrodes to generate a plurality of differences comprising a first difference and a second difference, wherein the first difference is the difference between the signals of the first detecting electrode and the second detecting electrode, and the second difference is the difference between the signals of the second detecting electrode and the third detecting electrode,

wherein when the display updates frames during detection by the detecting circuit, the signals of the second electrodes comprises the mutual capacitive coupling signals and the noises from the display, and the differences suppresses the noises.

12. The detecting method according to claim 11, wherein the second electrodes are capacitively coupled to the display, and the noises of the signals of the first detecting electrode, the second detecting electrode and the third detecting electrode are a first noise, a second noise and a third noise separately when the display updates frames during detection by the detecting circuit, wherein the values of the first noise and the second noise approximate to each other, and the values of the second noise and the third noise approximate to each other.

13. The detecting method according to claim 12, wherein the first difference is the difference between the mutual capacitive coupling signals of the first detecting electrode and the second detecting electrode after the first noise and the second noise cancel out when the detecting circuit generates the first difference by the subtraction between the signals of the first detecting electrode and the second electrode, and the second difference is the difference between the mutual capacitive coupling signals of the second detecting electrode and the third detecting electrode after the second noise and the third noise cancel out when the detecting circuit generates the second difference by the subtraction between the signals of the second detecting electrode and the third electrode, so as to suppress the noises from the display.

14. The detecting method according to claim 11, wherein the touch panel comprises a first insulating layer and a second insulating layer, wherein the first electrodes are located between the first insulating layer and the second insulating layer, and the second electrodes are located between the second insulating layer and the display.

15. The detecting method according to claim 11, wherein the area of the first electrodes outside of the intersecting area of the first electrodes and the second electrodes is larger than the area of the second electrodes outside of the intersecting area of the first electrodes and the second electrodes.