Pointing member, position detection apparatus and position detection method capable of detecting position of and pressure applied to pointing member

摘要

Methods and apparatus are provided to further facilitate detection not only of a position on a position detector pointed to by a pointing member, but also of information other than the position information such as pen pressure applied to the pointing member, in a position detection apparatus of the electrostatic coupling type. In one embodiment, a pointing member includes a first electrode substantially in the form of a rod, a substantially cylindrical second electrode disposed in such a manner as to surround the first electrode, and a transmission signal production section for producing a signal of a first frequency f1 and another signal of a second frequency f2 different from the first frequency f1 and controlling a phase difference between the signals in response to pressure applied to the pointing member. On a position detector side, the signal of the first frequency f1 is used for position detection of the pointing member, and the phase difference is used for detection of information other than the position information such as pen pressure on the pointing member. Alternatively, a pulse signal having a pulse width corresponding to pressure applied to the pointing member is produced, and on the position detector side, the position, pen pressure and so forth are detected from the pulse signal and the pulse width.

主权项

1. A position detection apparatus, comprising:
a pointing member which, in operation, transmits a signal for position pointing; and a position detector including a sensor section that is configured to be pointed to at a position thereof by said pointing member and to receive the signal for position pointing transmitted from said pointing member; wherein said position detector is configured to detect the position on said sensor section pointed to by said pointing member based on the signal for position pointing received by said sensor section; wherein said pointing member includes a transmission signal production section including two different frequency signal production sections which, in operation, respectively produce a signal of a first frequency and a signal of a second frequency that is different from the first frequency for frequency multiplexed transmission in a time-staggered but partially overlapping manner wherein the signal of the first frequency is indicative of a start timing of a time difference and the signal of the second frequency is indicative of an end timing of the time difference; wherein the transmission signal production section includes a delay setting circuit comprising a variable capacitor parallel to a periodic switch, the variable capacitor having one end coupled to a predetermined voltage through a resistor, the variable capacitor having capacitance that varies according to a pressing force applied to said pointing member when said pointing member points to the position on said sensor section, and the transmission signal production section, in operation, controls the time difference based on a time required to charge the variable capacitor to a defined threshold voltage; wherein the delay setting circuit, when the periodic switch is in an OFF state, charges the variable capacitor and causes the first frequency signal production section to produce the signal of the first frequency and, when the defined threshold voltage is reached, causes the second frequency signal production section to produce the signal of the second frequency to introduce the time difference between the signal of the first frequency and the signal of the second frequency and, when the periodic switch is in an ON state, discharges the variable capacitor; wherein said position detector detects the position on said sensor section pointed to by said pointing member based on at least one of the signal of the first frequency and the signal of the second frequency; and wherein said position detector detects the pressing force applied to said pointing member when said pointing member points to the position on said sensor section based on the time difference between the signal of the first frequency and the signal of the second frequency.