Stylus position detection system for optical touch panel
US5107253A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 13, 1989 |
| Grant date | Apr 21, 1992 |
| Priority date | — |
| Expiry date | Nov 13, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/0421
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A detection circuit (30, 32) for carrying out a rapid search technique for locating the position of a stylus (12) relative to a display screen (10). A microprocessor (34) and related components select a group of light detectors (20, 28) that are positioned near the display screen (10). The summed output current of the selected group of detectors (20, 28) is monitored to determine whether the output of any detector in the selected group is reduced because of the presence of a stylus (12). Whenever the selected group shows such reduction in output current, that selected groups is divided into two subgroups. The subgroup having reduced current output due to the presence of the stylus (12) is further divided until the particular detector(s) having reduced output current is found, the position of the detector is correlated to the location of the stylus (12) relative to the screen (10).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.