US3849979A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic digital clocks
Assignee: Noritake Itron Corp
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Filing: 1973-07-24
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Granted: 1974-11-26
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Expires: 1993-07-24
Abstract
Abstract In an electronic digital clock wherein letters representing the time and a symbol PM or AM are displayed by luminous display tubes driven by an electronic driving circuit, the brightness of the luminous display tubes is varied by a photoelectric element responsive to the brightness of the ambient light.
Inventors
- 👤 M Tanji
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 02:54
CPC Classifications
G; G04; G04G; G04G9/00; G04G9/0017
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
102 words
In an electronic digital clock of the type wherein letters are displayed by luminous display tubes driven by an electronic driving circuit, the improvement which comprises each of said luminous display tubes having a cathode electrode, a grid electrode and a plurality of luminous electrodes which are arranged to display a predetermined letter and are driven by time signals produced by said electronic driving circuit, and means responsive to the brightness of the ambient light for varying the brightness of said luminous display tubes including a photoelectric element connected for each said tube to said cathode electrode to vary its bias potential.
Claim 2
Dependent Claim
102 words
In an electronic digital clock of the type wherein letters are displayed by luminous display tubes driven by an electronic driving circuit, the improvement which comprises each of said luminous display tubes having a cathode electrode, a grid electrode and a plurality of luminous electrodes which are arranged to display a predetermined letter and are driven by time signals produced by said electronic driving circuit, and means responsive to the brightness of the ambient light for varying the brightness of said luminous display tubes including a photoelectric element connected for each said tube to said cathode electrode to vary its bias potential.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-25 | 1978-05-27 | 1978-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-25 | 1982-05-27 | 1982-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-25 | 1986-05-27 | 1986-11-26 | $7700.00 | Window Closed / Lapsed |