タッチパネル・システムの位置測定装置

Japanese Patent JPH061429

B2

A capacitive touch panel system (10) having a faceplate (14) with an electrically conductive layer (20) of a consistent resistivity employs a position measurement apparatus (12) to generate an address signal indicative of a position (46) on the faceplate in contact with a stylus (48). The position measurement apparatus includes a position measurement signal source (56) that generates a square-wave measurement signal of a frequency that varies in a substantially random manner. The position measurement signal is applied to a first pair of opposed electrodes (36) and (40) and a second pair of opposed electrodes (38) and (42) positioned along respective side margins (26, 30, 28, and 32) of the faceplate. The resistivity of the conductive layer establishes effective resistances of Rx and Ry between the respective first and second pairs of electrodes. Position measurement subcircuits (54a-54d) are locked-in with the random measurement signal frequencies to measure currents drawn through the electrodes whenever the stylus contacts the conductive layer, thereby to form an address signal indicative of the location at which the stylus contacts the faceplate. The random measurement signal frequencies reduce the susceptibility of the position measurement apparatus to electromagnetic noise and distributes over a relatively broad bandwidth the electromagnetic noise generated by the position measurement apparatus.

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JPH09305296	COORDINATE INPUT DEVICE
JP2003058319	TRANSPARENT TOUCH PANEL AND ITS MANUFACTURING METHOD

ROBAATO DEII MEDOZU
ROJAA JEE MATSUKOI

JP14926689A

January 05, 1994

June 12, 1989

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TEKTRONIX INC

G06F3/045; G06F3/041; G06K11/06; (IPC1-7): G06F3/033; G06F3/03

JPS6358529A

松隈 秀盛

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