Method for calibration of capacitive touch screen and capacitive touch apparatus

1. A method for calibration of a capacitive touch screen, the method comprising:

when a capacitive touch screen powers up, obtaining a temporary reference capacitance value of a touch detection point of the capacitive touch screen;

obtaining a first difference between a backup reference capacitance value of the touch detection point and the temporary reference capacitance value of the touch detection point; and

determining a reference capacitance value of the touch detection point according to the first difference and a first preset threshold, wherein the first preset threshold is a value greater than zero, and wherein determining the reference capacitance value of the touch detection point comprises:

in response to the first difference being less than the first preset threshold, adopting the temporary reference capacitance value as the reference capacitance value;

in response to the first difference being greater than the first preset threshold,

obtaining a detected capacitance value of the touch detection point;

obtaining a second difference between the detected capacitance value of the touch detection point and the temporary reference capacitance value of the touch detection point;

when the second difference is less than a second preset threshold, updating the reference capacitance value of the touch detection point to be the temporary reference capacitance value; and

when the second difference is greater than the second preset threshold, obtaining a third difference between the second difference and the first difference and determining the reference capacitance value of the touch detection point according to the third difference and a third preset threshold; and

using the reference capacitance value to detect a touch on the capacitive touch screen.

2. The method according to claim is claim 1 , wherein determining the reference capacitance value of the touch detection point according to the third difference and the third preset threshold comprises:

when the third difference is less than the third preset threshold, updating the reference capacitance value of the touch detection point to be the backup reference capacitance value; and

when the third difference is greater than the third preset threshold, updating the reference capacitance value of the touch detection point to be the detected capacitance value.

3. The method according to claim 2 , further comprising:

updating reference capacitance values of other touch detection points of the touch screen to be the temporary reference capacitance value, if the second difference is less than the second preset threshold;

updating reference capacitance values of other touch detection points of the touch screen to be the backup reference capacitance value, if the third difference is less than the third preset threshold; and

updating reference capacitance values of other touch detection points of the touch screen to be the detected capacitance value, if the third difference is greater than the third preset threshold.

4. The method according to claim 2 , further comprising:

updating the backup reference capacitance value of the touch detection point to be the temporary reference capacitance value when the second difference is less than the second preset threshold; and

updating the backup reference capacitance value to be the detected capacitance value when the third difference is greater than the third preset threshold.

5. The method according to claim 4 , further comprising:

updating reference capacitance values of other touch detection points of the touch screen to be the temporary reference capacitance value, if the second difference is less than the second preset threshold;

updating reference capacitance values of other touch detection points of the touch screen to be the backup reference capacitance value, if the third difference is less than the third preset threshold; and

updating reference capacitance values of other touch detection points of the touch screen to be the detected capacitance value, if the third difference is greater than the third preset threshold.

6. A capacitive touch apparatus comprising:

a capacitive touch screen; and

a processor configured to:

when the capacitive touch screen powers up, obtain a temporary reference capacitance value of a touch detection point of the capacitive touch screen and a first difference between a backup reference capacitance value of the touch detection point and the temporary reference capacitance value of the touch detection point;

obtain a reference capacitance value of the touch detection point according to the first difference and a first preset threshold; and

use the reference capacitance value to detect a touch on the capacitive touch screen;

wherein a value of the first preset threshold is not zero, and wherein obtaining the reference capacitance value of the touch detection point comprises:

in response to the first difference being less than the first preset threshold, adopting the temporary reference capacitance value as the reference capacitance value;

in response to the first difference being greater than the first preset threshold,

obtaining a detected capacitance value of the touch detection point;

obtaining a second difference between the detected capacitance value of the touch detection point and the temporary reference capacitance value of the touch detection point;

in response to the second difference being less than a second preset threshold, updating the reference capacitance value of the touch detection point to be the temporary reference capacitance value; and

in response to the second difference being greater than the second preset threshold, obtaining a third difference between the second difference and the first difference and determining the reference capacitance value of the touch detection point according to the third difference and a third preset threshold.

7. The touch apparatus according to claim 6 , wherein the processor is configured to determine the reference capacitance value of the touch detection point according to the third difference and the third preset threshold by:

updating the reference capacitance value of the touch detection point to be the backup reference capacitance value when the third difference is less than the third preset threshold; and

updating the reference capacitance value of the touch detection point to be the detected capacitance value when the third difference is greater than the third preset threshold.

8. The touch apparatus according to claim 7 , wherein the processor is further configured to:

update reference capacitance values of other touch detection points of the touch screen to be the temporary reference capacitance value, when the second difference is less than the second preset threshold;

update reference capacitance values of other touch detection points of the touch screen to be the backup reference capacitance value, when the third difference is less than the third preset threshold; and

update reference capacitance values of other touch detection points of the touch screen to be the detected capacitance value, when the third difference is greater than the third preset threshold.

9. The touch apparatus according to claim 7 , wherein the processor is further configured to:

update the backup reference capacitance value to be the temporary reference capacitance value, when the second difference is less than the second preset threshold; and

update the backup reference capacitance value to be the detected capacitance value, when the third difference is greater than the third preset threshold.

10. The touch apparatus according to claim 9 , wherein the processor is further configured to:

update reference capacitance values of other touch detection points of the touch screen to be the temporary reference capacitance value, when the second difference is less than the second preset threshold;

update reference capacitance values of other touch detection points of the touch screen to be the backup reference capacitance value, when the third difference is less than the third preset threshold; and

update reference capacitance values of other touch detection points of the touch screen to be the detected capacitance value, when the third difference is greater than the third preset threshold.