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:
Jan. 03, 1978
Filed:
Mar. 29, 1976
William H Ryan, Toledo, OH (US);
Owens-Illinois, Inc., Toledo, OH (US);
Abstract
A circuit and method for obtaining gray scale in gas discharge display panels which uses only one discharge site per resolution element, does not require extensive electronic memory and provides a continuous, broad intensity range. A video signal is sampled at predetermined time intervals and the samples are stored as potentials proportional to the magnitude of the video signal at the moment of sampling. Trigger signals are then generated from the samples, each trigger signal having a wave form with at least one dimension proportional to the potential of the associated sample. A maintain voltage is applied to all elements of the matrix display panel which has a magnitude somewhat less than the lower limit of the bistable region in which gas discharge panels are normally operated. Thus, a site cannot be turned 'on' in the normal sense of initiating a sequence of discharges which continues indefinitely. However, the application of the trigger voltage can initiate a sequence of discharges which continues for a substantial number of cycles before dying out. The number of cycles for which the discharge sequence persists depends on the magnitude and duration of the addressing trigger voltage. If the panel is operated in a refresh mode (the addressing pulses are applied repetitively), the average brightness of the light emitted may be controlled by varying the magnitude of the trigger pulse voltage to obtain a luminance range of more than 30 to one. This gray scale method may be used to address a matrix display panel with video information using a line-at-a-time addressing with red, green and blue phosphors.