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:
Oct. 30, 1984
Filed:
Jun. 02, 1982
Michitaka Osawa, Yokohama, JP;
Hitoshi Maekawa, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A gamma correction circuit is provided with a first circuit including a first linear element and a first non-linear element connected in series in the above order and a second circuit including a second non-linear element and a second linear element connected in series in the above order. A first connection point is located between the first linear element and the second non-linear element and a second connection point is located between the first non-linear element and the second linear element. A current source for converting a video signal voltage into a current output is connected to the second connection point. Two common collector (or common drain) transistors have their collectors (or their drains) connected to a power supply line. The input terminals of these transistors are connected to the connection point between the first linear element and the first non-linear element and to the connection point between the second non-linear element and the second linear element respectively, and the output terminals are connected to each other through a resistor. In order to decrease the junction capacitance of the transistors as the video signal voltage level increases, a voltage regulator circuit is connected between the power supply line and the first connection point.