POINTER DETECTION APPARATUS AND POINTER DETECTION METHOD
First Claim
1. A pointer detection apparatus, comprising:
- (a) a conductor pattern including a plurality of first conductors disposed in a first direction and a plurality of second conductors disposed in a second direction which crosses the first direction;
(b) a code string signal production circuit configured to produce a plurality of signals based on a plurality of code strings, each having the same code string and a phase different from each other;
(c) a transmission conductor selection circuit configured to selectively supply the plurality of signals produced by the code string signal production circuit to the plurality of first conductors, so as to supply each of the plurality of signals to at least two of the first conductors;
(d) a reception conductor selection circuit configured to selectively receive signals from the plurality of second conductors generated in response to the plurality of signals supplied to the plurality of first conductors;
(e) a signal detection circuit configured to detect a signal corresponding to a variation of capacitance between the conductor pattern and a pointer, based on the signals from the plurality of second conductors received via the reception conductor selection circuit;
(f) an analog to digital conversion circuit configured to convert the signal output from the signal detection circuit into a digital signal comprising a word string formed of a plurality of bits;
(g) a correlation detection circuit configured to determine correlation values between a plurality of code strings provided for correlation and the digital signal comprising a word string formed of a plurality of bits output from the analog to digital conversion circuit;
(h) a memory circuit configured to store the correlation values successively output from the correlation detection circuit; and
(i) a position calculation circuit configured to calculate a position on the conductor pattern pointed to by the pointer based on the correlation values.
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Accused Products
Abstract
A pointer detection apparatus includes a conductor pattern with first conductors disposed in a first direction and second conductors disposed in a second direction that crosses the first direction, and a code string signal production circuit for producing signals based on orthogonal code strings with phases different from each other and supplying the produced signals to the first conductors. The apparatus also includes a signal detection circuit connected to the second conductors for detecting a signal corresponding to a variation of electrostatic capacitance between the conductor pattern and a pointer, an analog to digital conversion (ADC) circuit for converting the signal output from the signal detection circuit into a digital signal comprising a word string of multiple bits, and a correlation detection circuit for determining correlation values between the code strings and the word string. The apparatus also includes a memory for storing correlation values successively output from the correlation detection circuit, wherein the pointer is detected based on the correlation values.
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Citations
25 Claims
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1. A pointer detection apparatus, comprising:
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(a) a conductor pattern including a plurality of first conductors disposed in a first direction and a plurality of second conductors disposed in a second direction which crosses the first direction; (b) a code string signal production circuit configured to produce a plurality of signals based on a plurality of code strings, each having the same code string and a phase different from each other; (c) a transmission conductor selection circuit configured to selectively supply the plurality of signals produced by the code string signal production circuit to the plurality of first conductors, so as to supply each of the plurality of signals to at least two of the first conductors; (d) a reception conductor selection circuit configured to selectively receive signals from the plurality of second conductors generated in response to the plurality of signals supplied to the plurality of first conductors; (e) a signal detection circuit configured to detect a signal corresponding to a variation of capacitance between the conductor pattern and a pointer, based on the signals from the plurality of second conductors received via the reception conductor selection circuit; (f) an analog to digital conversion circuit configured to convert the signal output from the signal detection circuit into a digital signal comprising a word string formed of a plurality of bits; (g) a correlation detection circuit configured to determine correlation values between a plurality of code strings provided for correlation and the digital signal comprising a word string formed of a plurality of bits output from the analog to digital conversion circuit; (h) a memory circuit configured to store the correlation values successively output from the correlation detection circuit; and (i) a position calculation circuit configured to calculate a position on the conductor pattern pointed to by the pointer based on the correlation values. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method for detecting a pointer by a pointer detection apparatus having a conductor pattern that includes a plurality of first conductors disposed in a first direction and a plurality of second conductors disposed in a second direction which crosses the first direction, the method comprising:
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producing a plurality of signals based on a plurality of code strings, each having the same code string and a phase different from each other; selectively supplying the plurality of signals to the plurality of first conductors of the conductor pattern, so as to supply each of the plurality of signals to at least two of the first conductors; selectively switching those second conductors from which signals are to be received; detecting a signal corresponding to a variation of capacitance between the conductor pattern and a pointer based on the signals received from the selectively switched second conductors; converting the detected signal into a digital signal comprising a word formed of a plurality of bits; determining correlation values between the code strings provided for correlation and the digital signal comprising a word formed of a plurality of bits obtained by the conversion; storing the correlation values; and detecting the pointer based on the correlation values.
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Specification