
US Patent No: 5,081,451
Number of patents in Portfolio can not be more than 2000
Display system for use in vehicle
Stats
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Jan 14, 1992
Issued date -
Oct 17, 1989
filing date -
07/422,526
serial no -
Expired
status
Importance
Abstract
A display system for a vehicle is provided with a fluorescent display tube. An anode control circuit outputs a control signal for selecting one or more of anode electrodes of the display tube to output a first control signal in response to which the selected anode electrodes are supplied with a positive voltage to cause the flourescent display tube to make a display. A display condition judging circuit judges whether or not the anode control circuit is outputting the first control signal. A brightness judging circuit judges whether the surroundings of the fluorescent display tube are bright or dark. A filament control circuit outputs a second control signal for energizing a filament of the display tube when said display condition judging circuit judges that the anode control circuit is outputting the first control signal and/or when the brightness judging circuit judges that the surroundings of the display tube are bright. The filament control circuit ceases to output the second control signal when the anode control circuit does not output the first control signal and at the same time when the brightness judging circuit judges that the surroundings of the display tube are dark.
First Claim
Related Publications
International Classification(s)
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Cited Art
| Patent Info | (Count) | # Cites | Year |
|---|---|---|---|
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| 4,697,122 Slow acting photo lamp control | 26 | 1986 | |
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| 4,682,084 High intensity discharge lamp self-adjusting ballast system sensitive to the radiant energy or heat of the lamp | 42 | 1985 | |
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| 4,358,713 Brightness control device for light emitting display of electronic meter | 21 | 1980 | |
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| 4,868,459 Method of and circuit for brightness and temperature-dependent control of an LCD illuminator | 27 | 1987 | |