The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Dec. 29, 1998

Filed:

May. 19, 1995
Applicant:
Inventors:

Yasuhiro Yoshida, Nara, JP;

Kengo Takahama, Nara, JP;

Takao Tagawa, Kashihara, JP;

Assignee:
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
G09G / ;
U.S. Cl.
CPC ...
345104 ; 345174 ; 345179 ; 178 1807 ; 178 1903 ;
Abstract

Provided is a coordinate detection device capable of preventing the increase of development cost and the reduction of yield and dispensing with additional investment for the existing equipment. There are provided an LCD panel having electrodes and electrodes, a magnetic field generator which outputs an AC magnetic field from a tip end of its electrode, a differential amplifier, switching circuits which sequentially select electrodes of the LCD panel and connect the electrodes to the differential amplifier, and a coordinate detection circuit which detects the coordinates of a position in which the magnetic field generator is located based on a timing at which the electrodes are selected and an output of the differential amplifier. A coordinate detection function can be achieved by means of the LCD panel having the same structure as that of the LCD panel provided specially for image display. Furthermore, there is no need to form a closed loop in the electrodes of the LCD panel, which obviates the need of providing any board opposite to four sides of the LCD panel.


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