Patent ID: 8780072
Filing Date: 2014-07-15
Classification: G06F

Abstract:
1. A pointer detection apparatus for detecting a pointer positioned on a conductor pattern, the 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, the pointer detection apparatus comprising: a code supplying circuit having a plurality of code strings of different codes from each other, the code supplying circuit being configured to supply predetermined ones of the code strings to the first conductors disposed in the first direction; a correlation calculation code supplying circuit configured to supply correlation calculation codes that respectively correspond to the code strings; a correlation calculation circuit configured to carry out correlation calculation between signals produced in the second conductors disposed in the second direction and the correlation calculation codes; a detection circuit configured to detect the pointer positioned on said conductor pattern based on a level curve that results from the correlation calculation, the detection circuit being further configured to: (a) apply logarithmic conversion to the level curve; (b) determine a ratio between a gradient of an edge and a peak value of the level curve to which the logarithmic conversion is applied; (c) determine the pointer to be in a first hovering state at or beyond a first distance away from the conductor pattern if the ratio is at or below a first threshold value; (d) determine the pointer to be in a second hovering state at or within the first distance away from the conductor pattern if the ratio is at or above the first threshold value and at or below a second threshold value greater than the first threshold value; and (e) determine the pointer to be in contact with the conductor pattern if the ratio is at or above the second threshold value; and a conductor selection circuit configured to select, (i) in case the detection circuit determines the pointer to be in contact with the conductor pattern, one of the first conductors to which one of the code strings is supplied, and (ii) in case the detection circuit determines the pointer to be in the first or second hovering state, a plurality of the first conductors, which are connected with each other and to which one of the code strings is simultaneously supplied, and/or a plurality of the second conductors, which are connected with each other and from which the signals are received by the correlation calculation circuit for correlation calculation, wherein the width for pointer detection formed by a plural number of the first conductors to which said one of the code strings is simultaneously supplied is less than the width for pointer detection formed by a plural number of the second conductors from which the signals are received for the correlation calculation in case the first conductors are disposed farther away from a detection surface of the apparatus than the second conductors.