Lens systems for projection televisions
US7019793B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 3, 2004 |
| Grant date | Mar 28, 2006 |
| Priority date | — |
| Expiry date | Aug 3, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/7408
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Projection lens systems for use with cathode ray tube (CRT) projection televisions are provided which have positive first lens units (U1) and negative second lens units (U2) where the negative second lens units are customized in terms of at least one optical property for at least two of the colors of light produced by the CRTs with which the units are used. The at least one optical property is not spectral transmission, although the second lens units can also be customized for spectral transmission. As illustrated in FIGS. 1B–1F and FIGS. 8B–8F, such customization of a non-transmissive property provides an effective and cost effective approach for improving the color performance of CRT projection lens systems. Constructions for the positive first lens unit which improve image contrast and reduce manufacturing costs are also provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.