METHOD AND APPARATUS FOR SENSING PROXIMITY TOUCH

• US 20110017525A1
• Filed: 07/20/2010
• Published: 01/27/2011
• Est. Priority Date: 07/21/2009
• Status: Abandoned Application

• Current Assignee: Core River Semiconductor Co., Ltd.
• Original Assignee: Core River Semiconductor Co., Ltd.
• Inventors: KWAK, Hyun-soo, KIM, Yoon-ki
• Application Number:
  US12/840,244
• Publication Number:
  US 20110017525A1
• Time in Patent Office: Days
• US Class Current: 178/18.06
• CPC Class Codes: G06F 2203/04101 2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• 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 3/044 by capacitive means

Abstract

Method and apparatus for sensing a proximity touch by accumulating delays generated by the proximity touch for at least a predetermined number of times. Compared to general touches, a proximity touch generates a smaller size of delay than the minimum size that a sensor can sense, so it is difficult for conventional touch sensors to sense a proximity touch. Accordingly, for detection of a proximity touch, the proximity touch should generate a larger size of delay than the minimum size that a touch sensor can sense, and to this end, delays generated by a proximity touch are accumulated for at least a predetermined number of times. Then, the accumulated delays are compared with the minimum size that the sensor can sense so as to determine whether there is a proximity touch.

Claims

1. A proximity touch sensor comprising:

an input module for receiving input from outside of the sensor, the input module being configured to include a capacitor and changing the capacitance of the capacitor according to the input;

a comparator for comparing the voltage changed by the capacitance with a reference voltage and reversing its output signal when the voltage changed by the capacitance is equal to the reference voltage, the output signal of the comparator being used as a first clock signal;

a first counter for counting the number of the first clock signal and outputting a signal when the counted result matches a sensing number;

a second counter for counting the number of a second clock signal until it receives the output signal of the first counter; and

a touch determining module for determining the input as a touch based on the output of the second counter.

2. The sensor of claim 1, further comprising a current supplying module for supplying current to the sensor, the current supplying module changing its phase according to the output signal of the comparator.

3. The sensor of claim 1, further comprising a current limiting module for determining the signal period of the sensor.

4. The sensor of claim 3, wherein the current limiting module comprises a resistor, and reduces the noise of the sensor by changing the resistance of the resistor.

5. The sensor of claim 1, further comprising a sensing number generator for generating a sensing number, the sensing number being a number which can be set according outside conditions or the delay condition of the sensor system.

6. The sensor of claim 1, further comprising a clock generator for generating the second clock signal counted by the second counter.

7. The sensor of claim 1, further comprising a sensor enabling module for enabling the sensor, the sensor enabling module being disabled by the first counter.

8. The sensor of claim 1, wherein the comparator is Schmit trigger.

9. The sensor of claim 1, wherein the touch determining module sets the number of the counted second clock signal as a reference value when there is no input from the outside of the sensor, and determines an input from the outside of the sensor as touch when the number of the counted second clock signal exceeds the reference value.

10. A proximity touch sensor comprising:

an input module for receiving input from outside of the sensor, the input module being configured to include a capacitor and changing the capacitance of the capacitor according to the input;

a comparator for comparing the voltage changed by the capacitance with a reference voltage and reversing its output signal when the voltage changed by the capacitance is equal to the reference voltage, the output signal of the comparator being used as a first clock signal;

a first counter for counting the number of the first clock signal and outputting a signal when the counted result matches a sensing number;

a sensing number generator configured to generate the sensing number, wherein the sensing number is a number which can be set according the condition of the outer sensor system or the delay condition of the inner sensor system;

a second counter for counting the number of a second clock signal until it receives the output signal of the first counter;

a clock generator for generating the second clock signal counted by the second counter; and

a touch determining module for determining the input as a touch based on the output of the second counter.

11. The sensor of claim 10, further comprising a current supplying module for supplying current to the sensor, the current supplying module changing its phase according to the output signal of the comparator.

12. The sensor of claim 10, further comprising a current limiting module for determining the signal period of the sensor, wherein the current limiting module comprises a resistor, and reduces the noise of the sensor by changing the resistance of the resistor.

13. The sensor of claim 10, further comprising a sensor enabling module for enabling the sensor, the sensor enabling module being disabled by the first counter.

14. The sensor of claim 10, wherein the comparator is Schmit trigger.

15. The sensor of claim 10, wherein the touch determining module sets the number of the counted second clock signal as a reference value when there is no input from the outside of the sensor, and determines an input from the outside of the sensor as touch when the number of the counted second clock signal exceeds the reference value.

16. A method for sensing proximity touch comprising:

receiving an input;

changing the capacitance of a capacitor by the input;

accumulating delay time for the capacitor to discharge for at least a predetermined number, the delay time being determined by the change of the capacitance; and

determining the input as a touch when the accumulated delay time is greater than or equal to a predetermined time.

17. The method of claim 16, wherein the predetermined number is a number which can be set according outside conditions or the delay condition of the sensor system.

18. The method of claim 16, wherein the predetermined time is an accumulated delay time for the capacitor to discharge for at least the predetermined number, when there is no input from the outside of the sensor.