Electromagnetic energy interference seal for light beam touch panels
US4695827A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 20, 1984 |
| Grant date | Sep 22, 1987 |
| Priority date | — |
| Expiry date | Nov 20, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2229/8633
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An electromagnetic energy interference seal arrangement is provided for use in light beam touch panel systems. The electromagnetic energy interference seal includes the use of waveguides associated with the light beam sources and detectors to improve light beam touch panel performance. The waveguide size is selected so that it operates as a waveguide above cutoff frequency for the light beams but operates as a waveguide below cutoff frequency for blocking electromagnetic energy interference. The waveguides improve the light beam signal to noise ratio since they shade the detectors from reflections and from extraneous light such as from overhead room lighting. Bonding of part of the electromagnetic energy interference seal is effected by an electrically conductive compound which enables nondestructive disassembly when required. Environmental sealing strips are provided to cover the waveguide apertures to protect against dust, liquids and other environmental contaminants.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.