Position indicating apparatus for use in a digitizing tablet system
US4638119A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 16, 1984 |
| Grant date | Jan 20, 1987 |
| Priority date | — |
| Expiry date | Nov 16, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/03545
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A position indicating implement is disclosed having a first coil connected to a current source and a second coil inductively coupled with the first coil. A capacitor is connected in series with the second coil so that the current in the first coil induces a phase shifted current in the second coil. A tip extends from the barrel of the position indicating implement of the present invention. The tip is designed for placement on and movement over a digitizing tablet. A switch has been located near the tip so that it is easily accessible to a user's finger while holding the implement. The power source providing an alternating current to the first coil includes a digital switching circuit for producing a step function which approximates a sine wave and lacks any components at the second, third, fourth, fifth and sixth harmonics. The step function is filtered to produce a sine wave for delivery to the first coil. The switch near the tip of the implement may be used as a mouse switch so that the position indicating implement may be used as a mouse to indicate relative position rather than absolute position. Remote signaling may be accomplished by providing a switch in the circuit of the s…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.