Sawtooth shaped front screen
US4012115A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 10, 1975 |
| Grant date | Mar 15, 1977 |
| Priority date | — |
| Expiry date | Jul 10, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B21/60
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A transparent front projection screen is disclosed having a plurality of ridges on the back thereof interrupted by flat portions and a plurality of curved sawtooth shaped ridges on the front thereof. The back ridges serve as a prism like element for reflecting the light by internal reflection which is incident thereon from predetermined directions. The flat surfaces on the back of the screen pass light incident from certain undesired directions. The sawtooth shaped ridges on the front of the screen serve as elements for developing a vertical spread of light but eliminates front face reflection problems. The disclosure also teaches the proper location of a projector when used with a transparent front projection screen as described above.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.