Transparent screen having intermittent portions for reducing reflection from ambient light
US3966301A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 16, 1975 |
| Grant date | Jun 29, 1976 |
| Priority date | — |
| Expiry date | Oct 16, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B21/602
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A front projection screen manufactured from transparent material is disclosed. The back side of the screen includes a plurality of prism-like elements so that light incident upon the screen from a preferred direction is totally reflected by the screen, while light incident upon the screen from other directions will pass therethrough. The parallel ridges are intermittently interrupted by repeating surfaces formed parallel to the plane of the front surface of the screen. The sides of the prism-like elements on the back surface of the screen are curved to provide dispersion in a horizontal plane, while the front surface of the screen has segments of cylindrical columns formed thereon perpendicular to the prism-like elements to form an angular light spread in a vertical plane. The repeating surfaces formed on the back surface of the screen, and interrupting the plurality of parallel ridges thereon, permits ambient light directed from non-preferred directions to either be passed through the screen without reflection, or to be absorbed thereby, so that this light is not reflected back thereby. These repeating surfaces preferably, in the former case, comprise repeating planar surfaces, an…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.