Orthogonal frequency scan scheme in touch system
First Claim
1. A low-latency touch sensitive device, comprising:
- a. a plurality of first conductors and second conductors being arranged such that;
i. each of the conductors of the plurality of first conductors are located proximate to each of the conductors of the plurality of second conductors, such thatii. when the touch sensitive device is not being touched, a first level of signal is coupled between them, andiii. when the touch sensitive device is being touched, a second level of signal is coupled between them;
b. signal generator operatively connected to the plurality of first conductors, the signal generator adapted to simultaneously generate a plurality of unique frequency orthogonal signals from a set of unique frequency orthogonal signals having constant spacing (Δ
f) therebetween, and wherein a highest frequency of the plurality of unique frequency orthogonal signals is less than twice the lowest frequency in the plurality of unique frequency orthogonal signals, each unique frequency orthogonal signal being orthogonal to each of the other unique frequency orthogonal signals;
c. signal decoder operatively connected to the plurality of second conductors, the signal decoder adapted to detect a level for each of the plurality of unique orthogonal signals on each of the plurality of second conductors received during a plurality of sequential measurement periods (τ
), the measurement periods (τ
) being equal to, or greater than, the reciprocal of the constant spacing (Δ
f) between the plurality of unique frequency orthogonal frequencies;
d. touch event locator for determining coordinates of a touch event based, at least in part, on the detected level for each of the plurality of unique orthogonal signals on each of the plurality of second conductors.
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Abstract
System and processes for transmitting orthogonal frequencies on a touch sensor are provided. In one example process, the rows of the sensor panel can have signals transmitted thereon having orthogonal frequencies. The orthogonal frequencies can be separated by a frequency spacing (Δf) that is at least the reciprocal of a measurement period τ (e.g., an integration time) of the touch sensor. Touch events cause and correspond to signals on the columns, which can be received by a receive system including appropriate amplifiers. The orthogonal frequencies can be detected by the receiver with a Fourier Transform or filter bank. Separate digitization and signal processing can be implemented for every column. The receiver can measure the quantity of each of the orthogonal transmitted signals present on each column, identifying the rows in touch with each column and may also provide additional (e.g., qualitative) information concerning the touch.
9 Citations
18 Claims
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1. A low-latency touch sensitive device, comprising:
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a. a plurality of first conductors and second conductors being arranged such that; i. each of the conductors of the plurality of first conductors are located proximate to each of the conductors of the plurality of second conductors, such that ii. when the touch sensitive device is not being touched, a first level of signal is coupled between them, and iii. when the touch sensitive device is being touched, a second level of signal is coupled between them; b. signal generator operatively connected to the plurality of first conductors, the signal generator adapted to simultaneously generate a plurality of unique frequency orthogonal signals from a set of unique frequency orthogonal signals having constant spacing (Δ
f) therebetween, and wherein a highest frequency of the plurality of unique frequency orthogonal signals is less than twice the lowest frequency in the plurality of unique frequency orthogonal signals, each unique frequency orthogonal signal being orthogonal to each of the other unique frequency orthogonal signals;c. signal decoder operatively connected to the plurality of second conductors, the signal decoder adapted to detect a level for each of the plurality of unique orthogonal signals on each of the plurality of second conductors received during a plurality of sequential measurement periods (τ
), the measurement periods (τ
) being equal to, or greater than, the reciprocal of the constant spacing (Δ
f) between the plurality of unique frequency orthogonal frequencies;d. touch event locator for determining coordinates of a touch event based, at least in part, on the detected level for each of the plurality of unique orthogonal signals on each of the plurality of second conductors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification