Display-integrated type tablet device capable of detecting correct coordinates at a tip end of a detection pen by detecting external noise
US5491706A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 5, 1994 |
| Grant date | Feb 13, 1996 |
| Priority date | — |
| Expiry date | Apr 5, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F11/0754
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An induction voltage signal induced at a detection electrode of a detection pen is binarized by a slice voltage "e.sub.s ". The number of pulses existing in the binary signal is counted by a counting device. The resulting count value obtained by the counting device and the number of times of electrode scanning in an x-coordinate detection period or a y-coordinate detection period are compared with each other by means of a comparator. When the number of pulses is greater, an error detection alarm signal is output by an alarm device. Thus the existence of the pulses based on the error detection signal is detected in the binary signal based on the induction voltage signal from the detection electrode to output the error detection alarm signal. The above arrangement allows the coordinates at the tip end of the detection pen to be detected in a stable and correct manner even when external noise is detected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.