TOUCH SENSOR CHIP, TOUCH SENSING APPARATUS INCLUDING THE SAME, AND METHOD OF CONTROLLING NOISE OF TOUCH PANEL

• US 20130293511A1
• Filed: 05/07/2013
• Published: 11/07/2013
• Est. Priority Date: 05/07/2012
• Status: Active Grant

• Current Assignee: Melfas Incorporated
• Original Assignee: Melfas Incorporated
• Inventors: NAM, Sung-Sik
• Granted Patent: US 9,164,635 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• 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

Abstract

Provided are a touch sensor chip, a touch sensing apparatus including the same, and a method of controlling noise of a touch panel. The touch sensing apparatus includes: an electronic device which is driven by a clock signal; a touch panel which is placed adjacent to the electronic device and receives a touch signal; and a touch sensor chip which transmits a driving signal to the touch panel and hops a frequency of the driving signal by a hopping interval if a noise level at the frequency of the driving signal is equal to or higher than a noise threshold, wherein the hopping interval is set based on an exciting frequency of the touch sensor chip.

Claims

1. A touch sensing apparatus comprising:

an electronic device which is driven by a clock signal;

a touch panel which is placed adjacent to the electronic device and receives a touch signal; and

a touch sensor chip which transmits a driving signal to the touch panel and hops a frequency of the driving signal by a hopping interval if a noise level at the frequency of the driving signal is equal to or higher than a noise threshold,

wherein the hopping interval is set based on an exciting frequency of the touch sensor chip.

2. The touch sensing apparatus of claim 1, wherein the noise level is the magnitude of noise measured in a state where the driving signal is not transmitted to the touch panel.

3. The touch sensing apparatus of claim 2, wherein the electronic device is a display panel, and the touch panel is placed on a surface of the display panel.

4. The touch sensing apparatus of claim 3, wherein the hopping interval is smaller than a frequency of the clock signal of the display panel.

5. The touch sensing apparatus of claim 4, wherein the hopping interval is 5 to 43 kHz.

6. The touch sensing apparatus of claim 1, wherein the hopping interval is a minimum frequency interval that can be set by the touch sensor chip.

7. The touch sensing apparatus of claim 6, wherein the exciting frequency of the touch sensor chip is 200 to 1000 kHz, and the hopping interval is 1 to 2% of the exciting frequency of the touch sensor chip.

8. The touch sensing apparatus of claim 6, wherein if the noise level at a frequency to which the frequency of the driving signal was hopped by the hopping interval is equal to or higher than the noise threshold, the touch sensor chip re-hops the frequency of the driving signal by the hopping interval.

9. The touch sensing apparatus of claim 8, wherein the touch sensor chip re-hops the frequency of the driving signal within a range of +10 to −

10% of the exciting frequency of the touch sensor chip.

10. The touch sensing apparatus of claim 1, wherein the touch sensor chip does not hop the frequency of the driving signal if a touch on the touch panel occurs during a first time period from a time when the noise level becomes equal to or higher than the noise threshold and hops the frequency of the driving signal by the hopping interval if a touch on the touch panel does not occur during the first time period from the time when the noise level becomes equal to or higher than the noise threshold.

11. The touch sensing apparatus of claim 1, wherein the touch sensor chip does not hop the frequency of the driving signal during the second time period from the time when the touch on the touch panel is released.

12. The touch sensing apparatus of claim 10, wherein the each of the first time period and the second time period is a time period corresponding to 15 to 45 frames.

13. A touch sensor chip comprising:

a driving signal transmission unit which transmits a driving signal to a touch panel;

a touch determination unit which determines the occurrence of a touch and the location of the touch based on a touch signal received from the touch panel; and

a noise calculation unit which calculates a noise level at a frequency based on the touch signal; and

a frequency hopping unit which hops a frequency of the driving signal if the noise level at the frequency of the driving signal is equal to or higher than a noise threshold,

wherein the hopping interval is set based on an exciting frequency of the touch sensor chip.

14. The touch sensor chip of claim 13, wherein noise is generated by an electronic device outside the touch sensor chip, and the noise level is the magnitude of noise measured in a state where the driving signal is not transmitted to the touch panel.

15. The touch sensor chip of claim 13, wherein the hopping interval is a minimum frequency interval that can be set by the touch sensor chip.

16. The touch sensor chip of claim 15, wherein the hopping interval is 1 to 2% of the exciting frequency of the touch sensor chip, and the exciting frequency of the touch sensor chip is 200 to 1000 kHz.

17. The touch sensor chip of claim 15, wherein the frequency hopping unit re-hops the frequency of the driving signal if the noise level at a frequency to which the frequency of the driving signal was hopped by the hopping interval is equal to or higher than the noise threshold.

18. The touch sensor chip of claim 17, wherein the frequency hopping unit re-hops the frequency of the driving signal within a range of +10 to −

10% of the exciting frequency of the touch sensor chip.

19. The touch sensor chip of claim 13, wherein the frequency hopping unit does not hop the frequency of the driving signal if a touch on the touch panel occurs during a first time period from a time when the noise level becomes equal to or higher than the noise threshold and hops the frequency of the driving signal by the hopping interval if a touch on the touch panel does not occur during the first time period from the time when the noise level becomes equal to or higher than the noise threshold.

20. The touch sensor chip of claim 13, wherein the frequency hopping unit does not hop the frequency during the second time period from the time when the touch on the touch panel is released.

21. A method of controlling noise of a touch panel, the method comprising:

measuring a noise level at a frequency of a driving signal of a touch panel; and

hopping the frequency of the driving signal by a hopping interval which is set based on an exciting frequency of a touch sensor chip if the noise level is equal to or higher than a noise threshold.

22. The method of claim 21, wherein the measuring of the noise level comprises measuring the noise level at the frequency of the driving signal in a state where the driving signal is not transmitted to the touch panel.

23. The method of claim 21, further comprising:

not hopping the frequency of the driving signal if a touch on the touch panel occurs during a first time period from a time when the noise level becomes equal to or higher than the noise threshold; and

hopping the frequency of the driving signal by the hopping interval if a touch on the touch panel does not occur during the first time period from the time when the noise level becomes equal to or higher than the noise threshold.

24. The method of claim 21, further comprising:

not hopping the frequency of the driving signal during the second time period from the time when the touch on the touch panel is released.