Light guide, line-illuminating device, and image-scanning device
US7076148B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 25, 2005 |
| Grant date | Jul 11, 2006 |
| Priority date | — |
| Expiry date | May 25, 2025 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S385/901
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A light guide, a line-illuminating device, and an image-scanning device are provided which are excellent in uniformity of the light amount. A light-reflecting portion comprised of tubular concave surfaces becomes a reflecting surface having tubular convex surfaces when seen from the inside of the light guide. With such structure, even when the incident angle of light from a light source unit slightly displaces, the reflection angle in the tubular convex surfaces significantly changes. In an irregular surface having a triangular shape, as in a conventional example, the incident angle becomes almost uniform in the area far from the light source unit, and thereby the reflection angle also becomes uniform. Consequently, it is difficult to achieve uniform reflection in the main-scanning direction. However, with the tubular concave surfaces, light is reflected uniformly toward the upper surface as a light-emitting surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.