CAPACITIVE SENSING DEVICE
First Claim
Patent Images
1. A capacitive sensing device comprising:
- a plurality of driving electrodes formed in a column direction;
at least one sensing electrode formed in a row direction, such that capacitance is formed between the sensing electrode and the plurality of driving electrodes;
a multi-driving unit configured to simultaneously apply respective driving signals to N driving electrodes;
a sensing unit configured to obtain a sensed signal from the at least one sensing electrode, a value of the sensed signal depending on the capacitance; and
a control unit configured to encode the driving signals to be applied from the multi-driving unit to the N driving electrodes to have respective waveform patterns by setting signs represented by an N×
N driving matrix, and to decode the sensed signal obtained from the sensing unit using a decoding matrix corresponding to the driving matrix, whereby obtaining distribution of the capacitance formed between the driving electrodes and the at least one sensing electrode,wherein the driving matrix is obtained from an Hadamard matrix having rows and columns exceeding N, respectively, by removing a row and a column in which an absolute value of a sum of the signs in a row direction and a column direction respectively, is greatest.
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Abstract
A driving signal is applied to a plurality of driving electrodes using the driving matrix illustrated in FIG. 5A obtained by removing a row in which a sum of codes is greatest and a column having a transposition relationship with the row in a Hadamard matrix. Distribution of capacitance in intersection portions between a sensing electrode and a plurality of driving electrodes can be obtained using an inverse matrix of the driving matrix illustrated in FIG. 5B. Further, when decoding is performed using an extended matrix obtained by replacing “0” with “−1” in FIG. 5B, it is possible to average noise and to improve an S/N ratio.
26 Citations
10 Claims
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1. A capacitive sensing device comprising:
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a plurality of driving electrodes formed in a column direction; at least one sensing electrode formed in a row direction, such that capacitance is formed between the sensing electrode and the plurality of driving electrodes; a multi-driving unit configured to simultaneously apply respective driving signals to N driving electrodes; a sensing unit configured to obtain a sensed signal from the at least one sensing electrode, a value of the sensed signal depending on the capacitance; and a control unit configured to encode the driving signals to be applied from the multi-driving unit to the N driving electrodes to have respective waveform patterns by setting signs represented by an N×
N driving matrix, and to decode the sensed signal obtained from the sensing unit using a decoding matrix corresponding to the driving matrix, whereby obtaining distribution of the capacitance formed between the driving electrodes and the at least one sensing electrode,wherein the driving matrix is obtained from an Hadamard matrix having rows and columns exceeding N, respectively, by removing a row and a column in which an absolute value of a sum of the signs in a row direction and a column direction respectively, is greatest. - View Dependent Claims (2, 3, 4, 5, 10)
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6. A capacitive sensing device comprising:
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a plurality of driving electrodes formed in a column direction; at least one sensing electrode formed in a row direction, such that capacitance is formed between the sensing electrode and the plurality of driving electrodes; a multi-driving unit configured to simultaneously apply respective driving signals to N driving electrodes; a sensing unit configured to obtain a sensed signal from the at least one sensing electrode, a value of the sensed signal depending on the capacitance; and a control unit configured to encode the driving signals to be applied from the multi-driving unit to the N driving electrodes to have respective waveform patterns by setting signs represented by an N×
N driving matrix, and to decode the sensed signal obtained from the sensing unit using a decoding matrix corresponding to the driving matrix, whereby obtaining distribution of the capacitance formed between the driving electrodes and the at least one sensing electrode,wherein the decoding matrix is an extended matrix obtained by replacing a sign “
0”
with a sign “
1”
or “
−
1”
in an inverse matrix of the driving matrix. - View Dependent Claims (7, 8, 9)
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Specification