Capacitive touch panel and method for acquiring capacitance values
A method for acquiring capacitance of a capacitive touch panel includes acquiring a selected capacitance value at a selected point among a plurality of points at which a plurality of capacitances are present, in the capacitive touch panel, determining the selected capacitance value as a reference capacitance value, and performing a multi-driving using a balanced code, and acquiring a capacitance value from at least one point among the plurality of points using the reference capacitance value.
1. A method of acquiring capacitance values for a capacitive touch panel, the method comprising:
acquiring a selected capacitance value for a selected point from among a plurality of points respectively exhibiting a plurality of capacitances;
determining the selected capacitance value as a reference capacitance value; and
performing multi-driving using a balanced code to acquire a capacitance value from at least one point among the plurality of points using the reference capacitance value, wherein:
the balanced code is a code excluding at least one row or at least one column having a non-zero sum of all entries in a Hadamard matrix,
a sum of all entries included in the balanced code is zero, and
the number of rows included in the balanced code is different from the number of columns included in the balanced code.
2. The method according to claim 1 , wherein the performing of multi-driving comprises:
applying the balanced code as an input signal to the capacitive touch panel to acquire an equation having a plurality of capacitance values as variables; and
applying the reference capacitance value to the equation to acquire at least one capacitance value from among the plurality of capacitance values.
3. The method according to claim 1 , wherein the selected point is determined based on generation of low ground mass (LGM) noise.
4. The method according to claim 1 , wherein the selected capacitance value for the selected point is acquired by performing a single-driving.
5. The method according to claim 2 , wherein an input line of the capacitive touch panel comprises a first input line to an Mth input line, and an output line of the capacitive touch panel comprises a first output line to an Nth output line, and
the selected point is respectively associated with at least one line of the first output line to the Nth output line, where ‘M’ and ‘N’ are integers greater than 1.
6. The method according to claim 5 , wherein the balanced code is a code excluding one of a first row and a first column in the Hadamard matrix having M rows and M columns.
7. The method according to claim 5 , wherein the multi-driving comprises a first multi-driving performed by selecting P lines among the first input line to the Mth input line as a first group, wherein P is an integer greater than 1 and less than M.
8. The method according to claim 7 , wherein the balanced code is a code excluding one of a first row and a first column in the Hadamard matrix having P rows and P columns.
9. The method according to claim 7 , wherein the multi-driving further comprises a second multi-driving performed by selecting Q lines among the first input line to the Mth input line, except for the selected P lines, as a second group, wherein Q is an integer of 2 greater than 1 and less than (M-P).
10. The method according to claim 9 , wherein one of capacitance values from at least one point acquired by performing the first multi-driving is again determined as the reference capacitance value, and a capacitance value from at least one point among the plurality of points belonging to the Q lines is acquired using the again determined reference capacitance value.
11. A capacitive touch panel including a first input line to an Mth input line as an input line for sensing a touch input, and a first output line to an Nth output line as an output line, the capacitive touch panel comprising:
a reference capacitance setting unit configured to acquire a selected capacitance value at a selected point among a plurality of points respectively exhibiting a plurality of capacitances, and to determine the selected capacitance value as a reference capacitance value; and
a multi-driving execution unit configured to perform multi-driving using a balanced code to acquire a capacitance value from at least one point among the plurality of points using the reference capacitance value, wherein:
‘M’ and ‘N’ are integers greater than 1,
the balanced code is a code excluding at least one row or at least one column having a non-zero sum of all entries in a Hadamard matrix,
a sum of all entries included in the balanced code is zero, and
the number of rows included in the balanced code is different from the number of columns included in the balanced code.
12. The capacitive touch panel according to claim 11 , wherein the multi-driving execution unit performs multi-driving using the balanced code as an input signal to the capacitive touch panel to acquire an equation having a plurality of capacitance values as variables, and applies the reference capacitance value to the equation to acquire at least one capacitance value among the plurality of capacitance values.
13. The capacitive touch panel according to claim 11 , wherein the reference capacitance setting unit determines the selected point based on generation of low ground mass (LGM) noise.
14. The capacitive touch panel according to claim 11 , wherein the selected point is respectively associated with at least one line of the first output line to the Nth output line, and ‘M’ and ‘N’ are integers greater than 1.
15. The capacitive touch panel according to claim 14 , wherein the multi-driving comprises a first multi-driving performed by selecting P lines among the first input line to the Mth input line as a first group, and
the balanced code is a code excluding one of a first row and a first column in the Hadamard matrix having P rows and P columns, wherein P is an integer greater than 1 and less than M.
16. The capacitive touch panel according to claim 15 , wherein the multi-driving further comprises a second multi-driving process performed by selecting Q lines among the first input line to the Mth input line, except for the selected P lines, as a second group, wherein Q is an integer greater than 1 and less than (M-P).
17. The capacitive touch panel according to claim 16 , wherein one of capacitance values from at least one point acquired by performing the first multi-driving is again determined as the reference capacitance value, and a capacitance value from at least one point among the plurality of points belonging to the Q lines is acquired using the again determined reference capacitance value, when the second multi-driving is performed.
18. A method of acquiring capacitance values for a capacitive touch panel, the method comprising:
selecting a low ground mass (LGM) point exhibiting minimal LGM noise from among a plurality of points;
acquiring a LGM capacitance value for the LGM point and setting the LGM capacitance value as a reference capacitance value; and
performing multi-driving to acquire a capacitance value from at least one point among the plurality of points using the reference capacitance value by applying a balanced code as an input signal to the capacitive touch panel to acquire an equation having a plurality of capacitance values as variables, and applying the reference capacitance value to the equation to acquire at least one capacitance value from among the plurality of capacitance values, wherein:
the balanced code is a code excluding at least one row or at least one column having a non-zero sum of entries in a Hadamard matrix,
a sum of all entries included in the balanced code is zero, and
the number of rows included in the balanced code is different from the number of columns included in the balanced code.