Projector with auto focus device
US7165849B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 3, 2004 |
| Grant date | Jan 23, 2007 |
| Priority date | — |
| Expiry date | May 11, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/3185
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image displayed on a liquid crystal panel is projected on a projection surface by a projection lens such that the optical axis of the projection lens is perpendicular to the projection surface. An optical axis of a distance measurement light and an optical axis of a light receiving lens are each inclined a specified angle with respect to the optical axis of the projection lens to be not perpendicular to the projection surface so as to reduce noise caused by specularly reflected light that otherwise would be detected by the distance measurement unit when a highly reflective whiteboard is utilized as the projection surface. The distance measurement unit is formed by unitizing a light emitting element, a light emitting lens, the light receiving lens, and a light receiving element, and the distance measurement unit is held with the projection lens by a common holder.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.