Capacitance sensing apparatus and method, and touch screen apparatus

• US 8,976,149 B2
• Filed: 09/10/2012
• Issued: 03/10/2015
• Est. Priority Date: 07/09/2012
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Inventors: Kwon, Yong Il, Lee, Sang Ho, Park, Tah Joon, Hong, Kyung Hee
• Primary Examiner(s): Pervan, Michael
• Assistant Examiner(s): Lee, Andrew
• Application Number:
  US13/607,919
• Publication Number:
  US 20140009431A1
• Time in Patent Office: 911 Days
• Field of Search: 345173-178, 178 1801- 1907
• US Class Current: 345/174
• 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 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

There is provided a capacitance sensing apparatus including: a driving circuit unit sequentially applying a driving signal to each of a plurality of first electrodes; a sensing circuit unit including a first integrating circuit detecting a first change in capacitance generated in a plurality of second electrodes by the driving signal and a second integrating circuit connected to another first electrode adjacent to the first electrode to which the driving signal is applied; and an operating unit connected to the sensing circuit unit to determine a touch input, wherein the second integrating circuit detects a second change in capacitance generated due to noise in the another first electrode, and the operating unit determines the touch input based on the first and second changes in capacitance.

Claims

1. A capacitance sensing apparatus comprising:

a driving circuit unit to sequentially apply a driving signal to each of a plurality of first electrodes including a first electrode;

a sensing circuit unit including a first integrating circuit to detect a first change in capacitance generated in at least one of a plurality of second electrodes by the driving signal and a second integrating circuit connected to another first electrode of the plurality of first electrodes adjacent to the first electrode to which the driving signal is applied; and

an operating unit connected to the sensing circuit unit to determine a touch input,

the second integrating circuit detects a second change in capacitance generated due to noise, which is created by the driving signal being applied to the first electrode, in the another first electrode, and

the operating unit determines the touch input based on the first change in capacitance, which is generated in the at least one of the plurality of second electrodes, and the second change in capacitance, which is generated in the another first electrode.

2. The capacitance sensing apparatus of claim 1, wherein the first integrating circuit includes a variable capacitor and a non-inverting amplifier, the variable capacitor being controlled to allow an output value of the non-inverting amplifier to be 0 when noise is not introduced thereto.

3. The capacitance sensing apparatus of claim 1, wherein the second integrating circuit inverts and integrates the second change in capacitance.

4. The capacitance sensing apparatus of claim 1, further comprising a controlling unit performing a control operation such that the driving signal is sequentially applied to the plurality of first electrodes and the second integrating circuit is connected to the another first electrode adjacent to the first electrode to which the driving signal is applied.

5. The capacitance sensing apparatus of claim 1, wherein the detected second change in capacitance in the another first electrode, which is generated due to noise created by the driving signal being applied to the first electrode, is detected during a period when no driving signal is applied to the another first electrode.

6. The capacitance sensing apparatus of claim 1, wherein the sensing circuit unit further includes a subtractor calculating a voltage difference between an output voltage of the first integrating circuit and an output voltage of the second integrating circuit.

7. The capacitance sensing apparatus of claim 6, wherein the operating unit determines the touch input based on an output signal of the subtractor.

8. A capacitance sensing method comprising:

applying a driving signal to a first electrode of a plurality of first electrodes;

generating a first output voltage from a first change in capacitance generated in a plurality of second electrodes by the driving signal;

generating a second output voltage from a second change in capacitance generated due to noise in another first electrode of the plurality of first electrodes which is adjacent to the first electrode to which the driving signal is applied;

calculating a voltage difference between the first output voltage and the second output voltage; and

determining a touch input based on the calculated voltage difference.

9. The capacitance sensing method of claim 8, wherein the generating of the first output voltage is performed by non-inverting and integrating the first change in capacitance.

10. The capacitance sensing method of claim 8, wherein the generating of the first output voltage further includes controlling a variable capacitor to allow the first output voltage to be 0 when noise is not introduced thereto.

11. The capacitance sensing method of claim 8, wherein the generating of the second output voltage is performed by inverting and integrating the second change in capacitance.

12. A touch screen apparatus comprising:

a panel unit including a plurality of driving electrodes and a plurality of sensing electrodes;

a driving circuit unit applying a driving signal to each of the plurality of driving electrodes;

a sensing circuit unit sensing changes in capacitance generated in intersections between the plurality of driving electrodes to which the driving signal is applied and the plurality of sensing electrodes; and

a controlling unit controlling operations of the driving circuit unit and the sensing circuit unit,

the sensing circuit unit including first and second integrating circuits, the first integrating circuit detecting a first change in capacitance generated in the plurality of sensing electrodes by the driving signal and the second integrating circuit detecting a second change in capacitance generated due to noise in another driving electrode adjacent to the driving electrode to which the driving signal is applied.

13. The touch screen apparatus of claim 12, wherein the first integrating circuit includes a variable capacitor and a non-inverting amplifier, the variable capacitor being controlled to allow an output value of the non-inverting amplifier to be 0.

14. The touch screen apparatus of claim 12, wherein the sensing circuit unit calculates a voltage difference between an output voltage of the first integrating circuit and an output voltage of the second integrating circuit to generate an output signal to be input to the controlling unit.

15. The touch screen apparatus of claim 12, wherein the controlling unit performs a control operation so that the second integrating circuit is connected to the another driving electrode adjacent to the driving electrode to which the driving signal is applied.