Prism plate for efficiently emitting light flux within a predetermined range, and liquid crystal indicator and indicator illumination method using the same
US5467417A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 8, 1993 |
| Grant date | Nov 14, 1995 |
| Priority date | — |
| Expiry date | Sep 8, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S385/901
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An information indicator suitable for information processors such as personal computers, word processors and the like includes a light source, a scattering plate which scatters light from the light source, an indicator plate irradiated with scattered light from the scattering plate, and a prism plate operatively arranged with respect to the scattering plate and the indicator plate and having a prism-like protuberance structure formed at a side thereof. The prism plate is so disposed that the prism-like protuberance structure faces the scattering plate, and the angle 2.theta. constituting the prism-like protuberance structure is defined by the formula, 2.theta.>2/3.times.(.pi./2+2.times.arcsin (n'/n)), in this inequality, n is the refractive index of said prism plate medium, and n' is the refractive index of a material in which the prism plate is arranged.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.