Apparatus for determining position and writing pressure
US4488000A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 30, 1982 |
| Grant date | Dec 11, 1984 |
| Priority date | — |
| Expiry date | Sep 30, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/0433
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The disclosure is directed to an apparatus for determining position in a data space. A generally flat tablet is provided, the tablet being formed of a solid acoustically-conductive material. A movable element, such as a stylus, is adapted to be manually movable over the tablet surface, the movable element having a tapered tip which contacts the surface of the tablet. An acoustic transducer is coupled to the tip of the movable element. Fixed transducer means are coupled to the tablet. Means are provided for energizing acoustic energy to propagate in either direction between the transducer of the movable element and the fixed transducer means. The midrange frequency of the energy is selected such that the wavelength of the energy mode propagating parallel to the tablet surface is a function of the tablet thickness. Means are provided for determining the time of propagation of the acoustic energy travelling, in either direction, between the transducer of the movable element and the fixed transducer means. Each time of propagation is indicative of a coordinate position of the movable element. The pressure of the stylus tip on the tablet controls the amplitude of transmitted or received…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.