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POWER AND COMPONENT SAVING TECHNIQUES

IP.com Disclosure Number: IPCOM000025769D
Original Publication Date: 1987-Dec-31
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 93K

Publishing Venue

Xerox Disclosure Journal

Abstract

It is not considered good practice to use incandescent bulbs to illuminate panel indicators because they tend to burn out and need replacement. LED'S are much more reliable. On the other hand, redundant bulbing is a problem since the second bulb is already old when the first bulb burns out. Among the methods to extend the life of bulbs past the planned life of the product are to run at slightly below their rated voltage. This improves life greatly and causes only a small decrease in brightness. Another method is to run the lamp at low voltage when it is supposed to be "off' in order to keep the filament warm and reduce in-rush current when it is turned on. There are two additional methods.

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XEROX DISCLOSURE JOURNAL

POWER AND COMPONENT SAVING TECHNIQUES US. C1.355/14C Craig A. Smith
Ruediger W. Knodt

Proposed Classification

Int. C1. G03g 15/00

It is not considered good practice to use incandescent bulbs to illuminate panel indicators because they tend to burn out and need replacement. LED'S are much more reliable. On the other hand, redundant bulbing is a problem since the second bulb is already old when the first bulb burns out. Among the methods to extend the life of bulbs past the planned life of the product are to run at slightly below their rated voltage. This improves life greatly and causes only a small decrease in brightness. Another method is to run the lamp at low voltage when it is supposed to be "off' in order to keep the filament warm and reduce in-rush current when it is turned on. There are two additional methods.

1. Redundant bulbs would be provided but only one bulb would be lighted. A current flow sensor would tell the processor when a bulb failed. Then the processor would switch to a brand-new bulb (and remember the failed bulb if desired). This serial redundance is a much better method than the standard parallel method.

2. The lamps are only needed when someone is looking at them, therefore, reduce lamp voltage to the point where the lamp is just visible whenever no potential user is nearby. In the extreme, some or all of the lamps could be turned "off'. Use a light (visible or IR) or acoustic sensor to tell if someone is nearby. A passive, visible light sensor would be a preferred design. Brightness would return to normal whenever someone was nearby or when any control was actuated.

The...