Pointer, position detection apparatus and position detection method

摘要

A position detection apparatus of the electrostatic coupling type is provided, to detect not only a position of a pointer but also information other than the position information such as, for example, pointer pressure or side switch information. The pointer transmits two codes such that a pressure applied to a pen tip is associated with a time difference between the two codes. A position detector carries out a correlation matching operation between signals generated in reception conductors and correlation calculation codes corresponding to the two codes, to thereby detect a position on a sensor section pointed to by the pointer from a result of the correlation matching operation and based on at least one of the codes. The position detector further includes a pressure calculation circuit for detecting pressure applied to the pointer, which is associated with the time difference between the two codes, from the result of the correlation matching operation calculated by the correlation matching operation and based on the two codes.

主权项

1. A position detection apparatus, comprising:
a pointer including a transmission signal production section, which is configured to produce a signal based on two predetermined codes that are time-staggered but are partially overlapping timewise, whose binary sequences are identifiable thorough a correlation operation, wherein one of the binary sequences is indicative of a start timing of a time difference and the other of the binary sequences is indicative of an end timing of the time difference, and wherein the time difference is introduced between the two codes that is indicative of a variable pressure applied to said pointer by controlling production timings of said two binary sequences, the pointer being configured to transmit the signal produced by said transmission signal production section; a sensor section including a plurality of first conductors disposed in a predetermined direction and a plurality of second conductors disposed in a direction crossing with the predetermined direction and configured to receive the signal transmitted from said pointer; a correlation operation circuit configured to carry out a correlation operation between signals generated in conductors which form the plurality of first conductors and conductors which form the plurality of second conductors and predetermined correlation calculation codes corresponding to the two codes; a position calculation circuit configured to detect a position on said sensor section pointed to by said pointer, based on a result of the correlation operation calculated by said correlation operation circuit and based on at least one of the two codes; and a pressure calculation circuit configured to detect the pressure applied to the pointer in accordance with the time difference between the two codes, based on the result of the correlation operation calculated by said correlation operation circuit and based on the two codes.