Coordinates input apparatus
US4902858A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 10, 1988 |
| Grant date | Feb 20, 1990 |
| Priority date | — |
| Expiry date | Nov 10, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/046
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A system for detecting the types and statuses of position designating devices is incorporated in a coordinates input apparatus having a tablet constituting a coordinates input section, a plurality of position designating devices of different types, and a position detecting circuit for driving the tablet and detecting positions at which coordinates are input by the position designating devices. The system has an antenna coil disposed around a coordinates input range of the tablet, and a tuning circuit disposed in each of the position designating devices for transmitting radio waves in response to an external signal at an individual frequency determined in accordance with the type of the corresponding position designating device. An AC signal of predetermined frequencies is applied to the antenna coil so that it transmits radio waves. The types and statuses of the position designating devices are detected by judging the condition of the position designating circuits from signals within the antenna coil while the transmission of the radio waves is suspended. With this system, the types and statuses of a plurality of position designating devices can be detected without having to connec…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.