The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 16, 1997
Filed:
Aug. 24, 1995
Hiroshi Ando, Ibaraki, JP;
Hiroki Kinugawa, Kusatsu, JP;
Masahiko Sasada, Takatsuki, JP;
Minoru Miyata, Suita, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
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.