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:
Apr. 26, 1977
Filed:
Feb. 20, 1974
Ryuichi Kaneko, Ikuta, Tama, Kawasaki, JA;
Minori Yokozawa, Misono, Sagamihara, JA;
Shigemitsu Suzuki, Higashi-Shinozaki, Edogawa, Tokyo, JA;
Takeo Kamegaya, Kyodo, Setagaya, Tokyo, JA;
Other;
Abstract
A pulse width luminance modulation system for driving a gas discharge panel in line at a time. The driving circuit for the discharge cell comprises a CR time constant element in order to enlarge the contrast range of the picture to be displayed. The discharge cell is caused to produce glow discharge when the pulse width of the pulse width modulation driving pulse is wider than a certain value depending on the CR time constant to produce normal pulse width luminance modulation of the glow discharge, and the discharge cell is caused to produce instantaneous irradiation of which the intensity is dependent on a stored charge in the capacitive element C of the CR element when the driving pulse width is narrower than the certain value so as to widen the low luminance range and by suitably selecting the value of the CR element for obtaining continuity of the two luminance characteristics, and further the input signal for making luminance modulation is applied with a correction in order to make the .gamma. value of the luminance characteristic of the discharge cell a close approximation to that of a cathode ray tube after converting the input signal to a pulse code modulated signal for obtaining an easy .gamma. correction in the low luminance range.