System and method for determining touch positions based on passively-induced position-dependent electrical charges
US8183875B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 26, 2008 |
| Grant date | May 22, 2012 |
| Priority date | — |
| Expiry date | Dec 23, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/04166
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Systems and methods determine the position of a touch on a surface of a device, such as a touch-sensitive device, by using passively-induced position-dependent electrical charges. In such a method, the position of a touching implement is determined on the sensing surface of a device. The method includes charging the sensing surface during a first time period by connecting all four corners of the sensing surface to a reference voltage, and over a second time period discharging two adjacent corners of the sensing surface into an integrator capacitor while connecting the two opposite corners to ground. The first and second time periods together form a charge/discharge cycle that is repeated a plurality of times, after which an output of the integrator capacitor is measured. This sequence is performed for each of the four pairs of adjacent corners of the sensing surface, resulting in four integrator capacitor output measurements, each of the four measurements being associated with a different sensing surface edge. The position of the touching implement on the sensing surface is then calculated using the four charge measurements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.