← Back to Patent Explorer
US4818913A Expired / Lapsed US ⏱️ 0.0 years remaining

Aging method for thin-film electroluminescent display panel

Assignee: Sharp Corp
•
Filing: 1982-07-23
•
Granted: 1989-04-04
•
Expires: 2002-07-23
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract A method of aging a thin-film electroluminescent (EL) display element comprises the steps of applying an aging voltage to electrodes of the element, and changing the peak value of the aging voltage in accordance with the characteristics of the element which change during an aging period. An aging circuit to perform the above method is provided. In a specific example, the magnitude of the aging voltage is changed according to the relationship between the brightness of electroluminescence generated from the element and a driving voltage applied to the element. In another specific example, the magnitude of the aging voltage is changed such that the brightness of the electroluminescence is sustained to be substantially constant, thereby making operation points constant on the above characteristics.

Inventors

  • 👤 Kinishi Isaka
  • 👤 Masashi Kawaguchi
  • 👤 Hisashi Uede

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 18:03
CPC Classifications
H; H05; H05B; H05B33/00; H05B33/10

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 72 words
A circuit for aging a thin-film electroluminescent display element comprising: a constant current circuit for providing a constant current to electrode means of an element; rectangular wave generator means for providing rectangular waveform signals; and converting means for converting changes in impedance of the element during an aging procedure into changes in applied voltages so that an aging voltage applied to the element is changed in accordance with changes in said impedance.
Claim 2
Dependent Claim 72 words
A circuit for aging a thin-film electroluminescent display element comprising: a constant current circuit for providing a constant current to electrode means of an element; rectangular wave generator means for providing rectangular waveform signals; and converting means for converting changes in impedance of the element during an aging procedure into changes in applied voltages so that an aging voltage applied to the element is changed in accordance with changes in said impedance.
Claim 3
Dependent Claim 41 words
The circuit of claim 1, wherein the converting means varies said applied voltage in accordance with a formula of V=I·|Z|: wherein V: the voltage of the aging voltage I: the constant current Z: the impedance of the thin-film electroluminescent display element.
Claim 4
Dependent Claim 19 words
The circuit of claim 1, wherein the rectangular signals generated from the rectangular wave generator means are AC signals.

References Cited (Backward Citations)

US3185893A Cited
US3708708A Cited
US3731353A Cited
US4275336A Cited
US4412155A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1992-04-03 1992-10-03 1993-04-04 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1996-04-03 1996-10-03 1997-04-04 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2000-04-03 2000-10-03 2001-04-04 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag