Automatic brightness limiter automatic control circuit, contrast limiter control circuit, luminance/color difference signal processor and video display apparatus
US5699127A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 24, 1995 |
| Grant date | Dec 16, 1997 |
| Priority date | — |
| Expiry date | Aug 24, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/0122
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The object of the present invention is to easily compensate automatic brightness limiting performance and automatic contrast limiting performance even if a picture is displayed with a different aspect ratio and to prevent deterioration of picture quality such as gradation and sharpness. A picture display apparatus includes (1) an automatic brightness limiter (ABL) circuit including a comparison circuit for varying an EHT compensation starting point, an ABL gain control circuit for varying a slope of the EHT characteristic versus the APL, an ABL comparison voltage generator, a DAC for adjusting an ABL compensation starting point and a DAC for adjusting an ABL gain and (2) an automatic contrast limiter (ACL) circuit including another comparison circuit for varying an EHT compensation starting point, an ACL gain control circuit for varying a slope of the EHT characteristic versus the APL, an ACL comparison voltage generator, a DAC for adjusting an ACL compensation starting point and a DAC for adjusting an ACL gain.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.