Patent ID: 8581861

Claim:
A pointer position 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 orthogonal code signals, each having a predetermined time difference from each other, based on a code string having an orthogonal characteristic, each of the plurality of orthogonal code signals being configured to be supplied as a unit to the conductor pattern; (c) a transmission conductor selection circuit configured to selectively supply the plurality of orthogonal code signals produced by the code string signal production circuit to the plurality of first conductors, by supplying each of the plurality of orthogonal code signals to at least two of the first conductors simultaneously for a length of the signal, to increase a reception signal level due to said each of the plurality of orthogonal code signals so as to expand a detection range for the pointer; (d) a reception conductor selection circuit configured to selectively receive signals from the plurality of second conductors generated in response to the plurality of orthogonal code signals supplied to the plurality of first conductors; (e) a signal detection circuit configured to detect a signal corresponding to a variation of capacitance caused 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 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 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.