Touch panel controller, electronic apparatus, capacitance detection method, and position detection method
AssigneeSharp Kabushiki Kaisha
InventorMUTSUMI HAMAGUCHI
Life of this patent
Estimating the term…
Abstract
Sense lines in a self-capacitance touch panel are multiplexed. A touch panel controller (3) includes a drive circuit (4) that drives drive lines (D0 through D(K-1)), based on a drive code series, a code multiplication unit (11) that reads multiple linear sum signals along the sense lines (S0 through S(M-1)), based on the charges of detection electrodes (E) and performs an inner product computation with a detection code series, and a detection circuit (6) that detects a capacitance or a change in the capacitance.
Claims11
A touch panel controller configured to control a touch panel that detects a capacitance or a change in the capacitance between a plurality of electrodes and a touch detection target, the electrodes being arranged at intersection points of a plurality of first signal lines and a plurality of second signal lines, the touch panel controller comprising:
- a drive circuit that turns on a first switch element between each of the electrodes and at least two of the first signal lines and drives the first signal lines a plurality of times in accordance with a first code series as a vector having elements of a number equal to a number of the first signal lines,
- a code multiplication unit that turns on a second switch element between each of the electrodes and corresponding one of the second signal lines, reads a plurality of linear sum signals responsive to charges of the electrodes along the second signal lines, and performs a plurality of times an inner product computation on a vector having as elements the linear sum signals and a second code series as a vector having elements of a number equal to a number of the second signal lines, and
- a detection circuit that detects the capacitance or the change in the capacitance by calculating a product of an inverse matrix of a matrix that is obtained by arranging a plurality of vectors, each vector representing the second code series, a matrix that is obtained by arranging vectors, each vector including the plurality of linear sum signals, and an inverse matrix of a matrix that is obtained by arranging a plurality of vectors, each vector representing the first code series.
A capacitance detection method of detecting a capacitance or a change in the capacitance between a plurality of electrodes and a touch detection target, the electrodes being arranged at intersection points of a plurality of first signal lines and a plurality of second signal lines, the capacitance detection method comprising:
- a drive step of turning on a first switch element between each of the electrodes and at least two of the first signal lines and driving the first signal lines a plurality of times in accordance with a first code series as a vector having elements of a number equal to a number of the first signal lines,
- a code multiplication step of, subsequent to the drive step, turning on a second switch element between each of the electrodes and corresponding one of the second signal lines, reading a plurality of linear sum signals responsive to charges of the electrodes along the second signal lines, and performing a plurality of times an inner product computation on a vector having as elements the linear sum signals and a second code series as a vector having elements of a number equal to a number of the second signal lines, and
- a detection step of, subsequent to the code multiplication step, detecting the capacitance or the change in the capacitance by calculating a product of an inverse matrix of a matrix that is obtained by arranging vectors, each vector representing the second code series, a matrix that is obtained by arranging vectors, each vector including the plurality of linear sum signals, and an inverse matrix of a matrix that is obtained by arranging vectors, each vector representing the first code series.
Dependencies are inferred from the claim text.