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.

Date of Patent:
Dec. 14, 1982

Filed:

Apr. 24, 1981
Applicant:
Inventors:

Hiroaki Fukuda, Nara, JP;

Shigeki Imai, Tenri, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G09G / ;
U.S. Cl.
CPC ...
340785 ; 340812 ; 350357 ;
Abstract

A circuit for providing a constant coloring current to a plurality of segment electrodes of an electrochromic display comprises a plurality of switching elements, say, transistors respectively connected to the segment electrodes for enabling the application of the constant coloring current to the segment electrodes, and an element for changing switching timings of the switching elements. A desirable amount of charge derived from the constant coloring current is applied to the segment electrodes regardless of the presence of the variations in electrical properties of the respective switching elements. In another form of the present invention, the changing element comprises a generator for generating a constant voltage, and a modifier for modifying a value of the constant voltage. In a further form of the present invention, the sizes of the respective switching elements, say, MOS transistors can be changed so that the factor W/L (W: the width of a channel of one of the MOS transistors, and L: the length of the channel) is selected so as to be proportional to the dimensions of the corresponding segment electrodes.


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