Projection lens
US5148320A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 23, 1991 |
| Grant date | Sep 15, 1992 |
| Priority date | — |
| Expiry date | Apr 23, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/16
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A projection lens system is for projecting an enlargement, on a display screen, of an image appearing on a faceplate of a cathode ray tube. The system includes six groups. The first group from the screen end is in the form of a positive meniscus. The second group includes a weak positive lens element having a surface convex to the screen. The third group includes a negative lens element. The fourth group includes a bi-convex lens element. The fifth group includes a weak positive element. The sixth group has a negative index of refraction. Each of the second and fifth groups include a plastic lens element that has at least one aspheric surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.