X-Y position sensor
US4659874A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 23, 1985 |
| Grant date | Apr 21, 1987 |
| Priority date | — |
| Expiry date | Sep 23, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/0442
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
In a sketch pad embodying the present invention, the sensing pad has an array of generally parallel pairs of adjacent sensing conductors which, for the purpose of this explanation, will be condidered as extending in the horizontal or X direction. Each conductor has a generally triangular shape, with the base of the triangle at one edge of the pad and the apex at the opposite edge. The conductors in each pair are complementary, that is, their bases are at opposite edges of the pad. Preferably the stylus used with the sensing pad has an electrode at its tip to which it applies an alternating current signal at a frequency that is suitably high for capacitive coupling to the sensing pad. To ascertain the X position of the stylus on the pad, the right or left set of conductors is connected to sensing circuitry and the other of these two sets is grounded. The sensed voltage then corresponds to the X position. Specifically, if the right set of conductors is connected to the sensing circuitry and the left set is grounded, the energy coupled to the right set from the signal emitted by the stylus corresponds to the relative widths, i.e. in the Y direction, of the right set of conductors at t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.