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:
Jun. 25, 1991
Filed:
Aug. 21, 1989
Masami Ikarashi, Furukawa, JP;
Kenichi Mitsumori, Furukawa, JP;
Alps Electric Co., Ltd., Tokyo, JP;
Abstract
There is provided a drive circuit for an electro-luminescence (EL) display device comprising a variable frequency oscillator circuit whose output signal frequency is externally modifiable, a voltage booster circuit for boosting the output signal of said variable frequency oscillator circuit to a predetermined level and supplying it to an EL display device as drive voltage, an impedance matching circuit whose impedance is externally modifiable and which is connected to said display device, a timing means for timing the duration of application of drive voltage to said display device and a control means for switching the output signal frequency of said variable frequency oscillator circuit and the impedance of said impedance matching circuit in accordance with said duration of voltage application. It is apparent that a drive circuit having such an arrangement as described above can effectively correct any shift of color of the light emitted from the connected EL display device and maintain the origninal color of the EL display device. Moreover, such a drive circuit for an EL display device can effectively compensate the loss of brightness of the screen of the EL display device connected therewith and hence prolong the apparent life of the display device.