Capacitive sensing apparatus
US9077345B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 8, 2009 |
| Grant date | Jul 7, 2015 |
| Priority date | — |
| Expiry date | Aug 27, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K2217/96079
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A capacitive sensing apparatus is described that incorporates a light guide having a light scattering means for illumination of the apparatus. The apparatus has a capacitive sensor mounted on a substrate that provides a capacitive sensing area for generating an electric field that emanates from the apparatus. A light source is arranged in optical communication with the light scattering means via the light guide. This arrangement acts to mitigate the effects of interference between the capacitive sensor and the light source. When an opaque substrate is employed an air gap is located between the substrate and the light guide so as to provide a substantially uniform illumination across the light guide. Appropriate selection of the refractive indices of the light guide, ng, and a transparent substrate, ns, provides the same desired uniform illumination in alternative embodiments. The capacitive sensing apparatus finds particular application within a touch sensitive display.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.