System and method for noise reduction in touch screen system
US6624835B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 9, 2001 |
| Grant date | Sep 23, 2003 |
| Priority date | — |
| Expiry date | Jun 24, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/045
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
There is disclosed a system and method for noise reduction in touch screen systems. A touch screen system comprises an analog to digital converter capable of converting to digital signals analog signals from at least one analog resistive film in a touch screen. The analog signal is indicative of a location on the touch screen. The invention comprises an apparatus for reducing noise in a touch screen comprising a microcontroller coupled to said analog to digital converter. The microcontroller receives a synchronization trigger signal, and in response to receiving the synchronization trigger signal, waits to receive digital signals from the analog to digital converter until the expiration of a period of time in which noise associated with the synchronization trigger signal has occurred. A method for reducing common mode noise is disclosed that actively senses and removes the ground return offset from the analog signals of the touch screen. Common mode noise is reduced by removing common mode noise from touch screen data signals by holding the touch screen data signals in a sample and hold circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.