Position detecting apparatus

• US 4,617,515 A
• Filed: 02/22/1985
• Issued: 10/14/1986
• Est. Priority Date: 02/22/1984
• Status: Expired due to Fees

• Current Assignee: Wacom Co Limited (Wacom)
• Original Assignee: Wacom Co Limited (Wacom)
• Inventors: Taguchi, Yoshinori, Yamanami, Tsuguya
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Mueller, R.
• Application Number:
  US06/704,223
• Time in Patent Office: 599 Days
• Field of Search: 33/1 M, 324/208, 324/207, 382/3, 340/365 L, 178/18, 178/19, 178/20
• US Class Current: 178/18.07
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

Disclosed is a position detecting apparatus which has a position detecting section having elongated magnetic bodies and a plurality of exciting lines and a plurality of detecting lines which are arranged alternately such as to cross the magnetic bodies orthogonally thereto. A driving power source is adapted to apply A.C. voltage of a predetermined frequency to the exciting lines. A position appointing magnetism generator applies a local magnetic bias to the magnetic bodies. The position appointed by the position appointing magnetism generator is detected through the detection of the voltages induced in the detecting lines. According to this arrangement, the position appointing magnetism generator can be handled easily because it is not connected to any stationary part of the apparatus, and the position can be detected at a high precision without being affected by external induction and noises and without producing noise which would affect nearby devices.

Claims

1. A position detecting apparatus comprising:

a position detecting section having elongated magnetic bodies and a plurality of exciting lines and a plurality of detecting lines which are arranged alternately such as to cross said magnetic bodies orthogonally thereto;

a driving power source adapted to apply A.C. voltage of a predetermined frequency to said exciting lines;

a position appointing magnetism generator for applying a local magnetic bias to said magnetic bodies; and

a detecting means for detecting the position appointed by said position appointing magnetism generator by detecting the voltages induced in said detecting lines.

2. A position detecting apparatus comprising:

an X-direction position detecting section having a plurality of elongated magnetic bodies arranged substantially in parallel, and a plurality of exciting lines and detecting lines which are arranged alternately such as to orthogonally cross said elongated magnetic bodies;

a Y-direction position detecting section having a construction similar to that of said X-direction position detecting section and superposed thereto;

a driving current source adapted to apply A.C. currents of a predetermined frequency to the exciting lines in said X- and Y-direction position detecting sections;

a position appointing magnetism generator adapted for applying local magnetic bias to said magnetic bodies of said X- and Y-direction position detecting sections;

X- and Y-direction signal selecting means connected to said detecting lines of said X- and Y-direction position detecting sections; and

a processing means for computing the coordinate position appointed by said position appointing magnetism generator from the induced voltage derived from said X- and Y-direction signal selecting means.

3. A position detecting apparatus according to claim 2, wherein said exciting lines of said X- and Y-direction position detecting sections are arranged such that the polarities of the magnetic fluxes formed by said exciting lines or the polarities of the electric currents formed in said exciting lines are inverted for every other magnetic body or every two or more magnetic bodies.

4. A position detecting apparatus according to claim 2 or 3, wherein said detecting lines of said X- and Y-direction position detecting sections are arranged such that the polarities of the magnetic fluxes formed by said detecting lines or the polarities of the electric currents formed in said detecting lines are inverted for every other magnetic body or every two or more magnetic bodies.

5. A position detecting apparatus according to claims 2 or 3, wherein either the X- and Y-direction exciting lines or the X- and Y-direction detecting lines or, alternatively, both of the X- and Y-directions exciting lines and X- and Y-direction detecting lines corresponding to X- and Y-direction magnetic bodies disposed at both ends of respective parallel rows and arranged closely to said magnetic bodies as compared with other exciting and/or detecting lines.

6. A position detecting apparatus according to claims 2 or 3, wherein said exciting lines are arranged more densely at both longitudinal ends of said magnetic bodies of said X- and Y-direction position detecting sections than at other portions of said magnetic bodies.