Opaque adapter for overhead projector
US4930886A · kind A · utility
0Cited by
7References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 8, 1988 |
| Grant date | Jun 5, 1990 |
| Priority date | — |
| Expiry date | Dec 8, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S353/04
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An opaque adapter for an overhead projector uses a hood with clamshell doors to provide generous access to the projector stage during transparency projection and efficient light shielding during opaque projection. The clamshell doors are oriented upon hinges slanted to the vertical so as to rise away from the stage when opened. Spring devices offset the gravitational forces on the doors, allowing rapid motor actuation with very little power. Dual dichroic optics maintain a cool stage despite high light intensity, and internal baffles further increase brightness.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.