Methods for coping with non-uniform phosphor aging in dual mode television receivers
US4670784A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 7, 1986 |
| Grant date | Jun 2, 1987 |
| Priority date | — |
| Expiry date | Jul 7, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/0122
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Methods and apparatus for solving the problem of non-uniform phosphor aging of the screen of a dual mode television receiver having the capability of displaying the picture image in two different aspect ratios, for example, 4:3 and 5:3. In one embodiment, the entire screen is illuminated during display of a 4:3 aspect ratio image on the central area of the screen so as to effect uniformity of aging over the entire screen. Alternatively, the areas at either side of the central 4:3 aspect ratio image area are not illuminated during display of 4:3 aspect ratio images but are, instead, post-aged following a period of display of such images. Another solution is to electrically compensate for the faster aging of the central 4:3 aspect ratio are of the screen when viewing 5:3 aspect ratio pictures.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.