Position information input apparatus and method
US6963331B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 2000 |
| Grant date | Nov 8, 2005 |
| Priority date | — |
| Expiry date | Mar 14, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/0386
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The invention aims to provide a coordinate input apparatus having high detection reliability and high efficiency and to control the influence of ambient light using a simple structure. The apparatus detects a light spot flashing on and off in a predetermined cycle and incident at a desired position on a coordinate input screen, and includes a detection device having photoelectric conversion elements corresponding to N pixels for detecting a light spot coordinate. The difference between signals from photoelectric elements in light emission state and in light non-emission state at each N pixel is found, and the smaller of the difference signals of the m-th pixel having the maximum difference signal is set as a threshold value. Effective pixels are identified based on the threshold value, and the coordinate is calculated by using the difference data of the selected effective pixels.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.