Digitizer and position encoders and calibration system for same
US4575581A · kind A · utility
Inventor
Key dates
| Filing date | Feb 6, 1984 |
| Grant date | Mar 11, 1986 |
| Priority date | — |
| Expiry date | Feb 6, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/045
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Digitizer incorporates two novel position encoders. One position encoder comprises means for periodic spatial calibration against an accurate pattern of reference marks, thereby improving accuracy to the limit of resolution. Optionally, it also includes temperature and humidity compensation. Superior accuracy is achieved without tight tolerance requirements for mechanical components. The same technique can be used for error detection in digital motion control. The other position encoder, used primarily for menu data entry, is based on a discrete resistor array, combined with pulse position modulation of array columns. Its main advantage is simplicity and low cost. The digitizer is ergonomically designed, so that the operator can digitize coordinates with the left hand while inputing from the menu with the right hand.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.