Method, Device, and System for Detecting Transmitter Approaching or Touching Touch Sensitive Display

• US 20150130734A1
• Filed: 11/10/2014
• Published: 05/14/2015
• Est. Priority Date: 11/08/2013
• Status: Active Grant

• Current Assignee: eGalax_eMPIA Technology Inc.
• Original Assignee: eGalax_eMPIA Technology Inc.
• Inventors: CHANG, CHIN-FU, YEH, SHANG-TAI
• Granted Patent: US 9,910,529 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• 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 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/038 Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry
• CPC Class Codes: G06F 3/0383 Signal control means within the pointing device
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04162 for exchanging data with external devices, e.g. smart pens, via the digitiser sensing hardware
• 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 3/0445 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

Abstract

A method is provided for detecting a transmitter approaching or touching a touch sensitive display. The transmitter transmits an electrical signal which is mixed from a plurality of signals having different frequencies. The display includes a liquid crystal layer between pixel electrodes and common electrodes and a plurality of second electrodes. The common electrodes include a plurality of first electrodes. A plurality of sensing points is located in the intersections of the plurality of first electrodes and the plurality of second electrodes. The method includes: calculating the total signal strength of a received signal with respect to each of the first electrodes; calculating the total signal strength of a received signal with respect to each of the second electrodes; calculating a relative position between the transmitter and the display according to the calculated total signal strengths of the received signals with respect to each of the first and second electrodes.

Claims

1. A method for detecting a transmitter approaching or touching a touch sensitive display, the transmitter transmitting an electrical signal mixed from a plurality of frequencies, the touch sensitive display including a liquid crystal layer disposed between pixel electrodes and common electrodes and a plurality of second electrodes, wherein the common electrodes include a plurality of first electrodes and a plurality of sensing points are formed at intersections of the first and second electrodes;

the method including the following steps of;

calculating the total signal strength of a received signal with respect to each of the first electrodes;

calculating the total signal strength of a received signal with respect to each of the second electrodes; and

calculating a relative position between the transmitter and the touch sensitive display according to the calculated total signal strengths of the received signals with respect to each of the first electrodes and the second electrodes.

2. The method of claim 1, wherein the common electrodes excluding the plurality of first electrodes are coupled to a direct-current (DC) potential to form a shielding region.

3. The method of claim 2, wherein when the common electrodes excluding the plurality of first electrodes are coupled to the DC potential, the total signal strength of the received signal with respect to each of the second electrodes is not calculated.

4. The method of claim 1, further comprising:

during blanking intervals of scanning performed by the touch sensitive display, calculating the total signal strength of the received signal with respect to each of the second electrodes.

5. The method of claim 1, further comprising:

during blanking intervals of scanning performed by the touch sensitive display, calculating the total signal strength of the received signal with respect to each of the first electrodes.

6. The method of claim 1, wherein the plurality of first electrodes are arranged in parallel to each other and parallel to horizontal pixel lines to be scanned by the liquid crystal layer and the order in which the total signal strength of the electrical signal received by each of the first electrodes is calculated is opposite to the order in which the liquid crystal performs the scanning.

7. The method of claim 6, further comprising:

determining if a horizontal pixel line being scanned is in an interference range of at least one first electrode; and

if the result of the determination is true, then suspending the calculations of the total signal strength of the electrical signal received by the at least one first electrode.

8. A touch processing device for detecting a transmitter approaching or touching a touch sensitive display, wherein the transmitter transmits an electrical signal mixed from a plurality of frequencies, and the touch sensitive display includes a liquid crystal layer disposed between pixel electrodes and common electrodes and a plurality of second electrodes, wherein the common electrodes include a plurality of first electrodes and a plurality of sensing points are formed at intersections of the first and second electrodes, the touch processing device being configured for:

calculating the total signal strength of a received signal with respect to each of the first electrodes;

calculating the total signal strength of a received signal with respect to each of the second electrodes; and

calculating a relative position between the transmitter and the touch sensitive display according to the calculated total signal strengths of the received signals with respect to each of the first electrodes and the second electrodes.

9. The touch processing device of claim 8, wherein the common electrodes excluding the plurality of first electrodes are coupled to a direct-current (DC) potential to form a shielding region.

10. The touch processing device of claim 9, wherein when the common electrodes excluding the plurality of first electrodes are coupled to the DC potential, the total signal strength of the received signal with respect to each of the second electrodes is not calculated.

11. The touch processing device of claim 8, further configured for calculating the total signal strength of the received signal with respect to each of the second electrodes during blanking intervals of scanning performed by the touch sensitive display.

12. The touch processing device of claim 8, further configured for calculating the total signal strength of the received signal with respect to each of the first electrodes during blanking intervals of scanning performed by the touch sensitive display.

13. The touch processing device of claim 8, wherein the plurality of first electrodes are arranged in parallel to each other and parallel to horizontal pixel lines to be scanned by the liquid crystal layer, and the order in which the total signal strength of the electrical signal received by each of the first electrodes is calculated is opposite to the order in which the liquid crystal performs the scanning.

14. The touch processing device of claim 13, further configured for:

determining if a horizontal pixel line being scanned is in an interference range of at least one first electrode; and

if the result of the determination is true, then suspending the calculations of the total signal strength of the electrical signal received by the at least one first electrode.

15. A touch sensitive display system for detecting a transmitter approaching or touching a touch sensitive display, wherein the transmitter transmits an electrical signal mixed from a plurality of frequencies, the touch sensitive display system comprising:

the touch sensitive display including;

a liquid crystal layer disposed between pixel electrodes and common electrodes; and

a plurality of second electrodes, wherein the common electrodes include a plurality of first electrodes and a plurality of sensing points are formed at intersections of the first and second electrodes; and

a touch processing device connected to the touch sensitive display, the touch processing device being configured for;

calculating the total signal strength of a received signal with respect to each of the first electrodes;

calculating the total signal strength of a received signal with respect to each of the second electrodes; and

calculating a relative position between the transmitter and the touch sensitive display according to the calculated total signal strengths of the received signals with respect to each of the first electrodes and the second electrodes.

16. The touch sensitive display system of claim 15, further comprising the transmitter.