Pen coordinate reading device with pen attribute detecting function
US6744426B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 10, 2000 |
| Grant date | Jun 1, 2004 |
| Priority date | — |
| Expiry date | May 3, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/03545
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A circuit mounted in the circuit board 69 of the pen 60 includes: a CR solution circuit 69e; an LC oscillation circuit 69c; and an FSK circuit 69d. The CR oscillation circuit 69e oscillates a signal with one of a plurality of different modulation frequencies that correspond to a plurality of different attributes, such as ink colors, pen tip thickness, and the like, of the pen. The LC oscillation circuit 69c is for oscillating a carrier wave for transmitting the signal oscillated by the CR oscillation circuit 69e. The FSK circuit 69d is for PSK modulating the oscillation frequency of the LC oscillation circuit 69c in accordance with the modulation frequency of the CR oscillation circuit 69e. The receiving side measures a time period at which the frequency of the carrier wave is maintained, thereby determining the period of the modulation frequency to know the pen attributes. Because it is sufficient to receive the signal from the pen for at least one period of time thereof, it is possible to shorten the time required to recognize the pen attributes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.