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Patent US5099178A successfully refreshed from Google Patents.
US5099178A
Expired / Lapsed
US
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Method and system for controlling the brightness of a vacuum fluorescent display
Assignee: Visteon Global Technologies Inc
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Filing: 1990-08-20
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Granted: 1992-03-24
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Expires: 2010-08-20
Abstract
Abstract A method and system for providing a wide range of variable brightness levels for a vacuum fluorescent (VF) display by changing the duty cycle of the driving signal beyond the limits of normal driving techniques by varying the frequency as well as the on-time of the driving signal. The driving signal is multiplexed by a programmed driver microcomputer to drive a plurality of grids. Consequently, by varying the frequency, the multiplex period is also varied. The driver microcomputer communicates with a host microcomputer as well as drivers and grids of the VF display to control the VF display. In addition, the driver microcomputer samples a VF filament signal to synchronize the VF display multiplex frequency with the frequency of the VF filament signal to reduce flicker at low display brightness levels. The method and system achieve a continuously variable appearance of the VF display from full bright to barely discernable.
Inventors
- 👤 Erich Bozzer
- 👤 James M. Raffa
- 👤 Thomas G. Burke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:57
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/22; G09G3/2007; G09G3/2014
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
105 words
A method for controlling the brightness of a vacuum fluorescent (VF) display, the display including anodes, grids and a filament, the method comprising the steps of: supplying an alternating current signal to the filament; generating control pulses for enabling display illumination, the control pulses having an on-time and an off-time and having a nominal frequency; and controlling the duty cycle of the control pulses to control display brightness, wherein the step of controlling includes the steps of modifying the on-time of the control pulses to provide a nominal range of display brightness and modifying the nominal frequency to expand the nominal range of display brightness.
Claim 2
Independent Claim
105 words
A method for controlling the brightness of a vacuum fluorescent (VF) display, the display including anodes, grids and a filament, the method comprising the steps of: supplying an alternating current signal to the filament; generating control pulses for enabling display illumination, the control pulses having an on-time and an off-time and having a nominal frequency; and controlling the duty cycle of the control pulses to control display brightness, wherein the step of controlling includes the steps of modifying the on-time of the control pulses to provide a nominal range of display brightness and modifying the nominal frequency to expand the nominal range of display brightness.
Claim 3
Dependent Claim
27 words
The method as claimed in claim 1 further comprising the step of coordinating the alternating current signal with the control pulses to obtain uniform perceived display brightness.
Claim 4
Dependent Claim
31 words
The method as claimed in claim 2 wherein the step of coordinating includes the step of supplying a feedback signal corresponding to the alternating current signal to modify the nominal frequency.
Claim 5
Dependent Claim
21 words
The method as claimed in claim 1 or claim 2 wherein the nominal frequency is derived from the alternating current signal.
Claim 6
Dependent Claim
17 words
The method as claimed in claim 1 wherein the control pulses are successively supplied to the grids.
Claim 7
Dependent Claim
99 words
A control system for a vacuum fluorescent (VF) display having anodes, grids and a filament, the system comprising: means for supplying an alternating current signal to the filament; means for generating control pulses for enabling display illumination wherein the control pulses have an on-time and off-time and a nominal frequency; control means for controlling the duty cycle of the control pulses to control display brightness, by modifying the on-time of the control pulses to provide a nominal range of display brightness and by modifying the nominal frequency of the control pulses to expand the nominal range of display brightness.
Claim 8
Dependent Claim
99 words
A control system for a vacuum fluorescent (VF) display having anodes, grids and a filament, the system comprising: means for supplying an alternating current signal to the filament; means for generating control pulses for enabling display illumination wherein the control pulses have an on-time and off-time and a nominal frequency; control means for controlling the duty cycle of the control pulses to control display brightness, by modifying the on-time of the control pulses to provide a nominal range of display brightness and by modifying the nominal frequency of the control pulses to expand the nominal range of display brightness.
Claim 9
Dependent Claim
26 words
The system as claimed in claim 6 further comprising means for coordinating the alternating current signal with the control pulses to obtain uniform perceived display brightness.
Claim 10
Dependent Claim
30 words
The system as claimed in claim 7 wherein said means for coordinating includes feedback means for supplying a feedback signal corresponding to the alternating current signal to the control means.
Claim 11
Dependent Claim
20 words
The system as claimed in claim 6 further comprising multiplexing means for successively supplying the control pulses to the grids.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-03-24 | 1995-09-23 | 1996-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-03-24 | 1999-09-23 | 2000-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-03-24 | 2003-09-23 | 2004-03-24 | $7700.00 | Window Closed / Lapsed |