LED array primary display light sources employing dynamically switchable bypass circuitry
First Claim
1. In an electrical circuit employing at least one LED or incandescent light element for illumination, the improvement comprising connecting at least one DSB element in parallel with said at least one light element so that when said light element fails, said circuit continues to pass current through said DSB to permit at least some remaining circuit components to function.
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Accused Products
Abstract
The invention comprises use of Dynamically Switchable Bypass (DSB) elements in association with one or more Light Emitting Diodes (LEDs) in arrays for illumination circuits to provide rugged, reliable lighting. The DSBs are selected from Transient Voltage Suppressors, including Silicon, Metal Oxide Varistors, and Multi Layer Varistors as well as Zener Diodes. The DSBs are not used as circuit protecting devices, but rather as alternative paths for electric current to bypass failed LEDs. Bi-directional TVSs are used as alternative electric paths for circuits using Alternating Current (AC) and parallel LED arrays that light on both phases of AC. Zener Diodes are used in parallel to, but in the opposite polarity orientation to, one or more LEDs in DC or rectified AC circuits. The inventive paired DSB/LED elements overcomes the black-out problems of prior series LED illumination systems, making possible the use of robust LEDs in illumination systems where reliability, long life, low power consumption, low heat output, resistance to shock, vibration, and humidity, and self-diagnosis are important. The DSB elements have breakdown voltages slightly higher than the LED(s) they support, so that when an LED fails, the conduction through the DSB begins. Because the conduction voltage of the DSB so nearly matches the conduction voltage of the LED(s), the remainder of the circuit continues to function as normal. The system is self-diagnostic in that any LED failure presents itself as a dark LED rather than as a whole string of dark LEDs. DSBs may be used with incandescent bulbs.
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Citations
27 Claims
- 1. In an electrical circuit employing at least one LED or incandescent light element for illumination, the improvement comprising connecting at least one DSB element in parallel with said at least one light element so that when said light element fails, said circuit continues to pass current through said DSB to permit at least some remaining circuit components to function.
- 10. In a panel illumination assembly comprising a faceplate and a circuit board disposed spaced below said faceplate, said circuit board having an array of light elements selected from LEDs and incandescent bulbs thereon oriented for illumination of pre-selected areas of said faceplate, the improvement comprising connecting at least one DSB element in parallel with at least one light element so that when said light element fails, said circuit continues to pass current through said DSB to permit other light elements in said circuit to function.
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16. Method of maintaining light output of a multi-element light element array illumination device having a lit portion, comprising the steps of:
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a) electrically connecting at least one DSB element in parallel with a preselected group of light elements of said illumination device;
b) supplying current to said light element illumination device so that said light elements are lit;
c) continuing to supply current to said light element illumination device after at least one light element fails, by passing current through said DSB element to permit other light elements of said device to remain lit;
d) thereby maintaining a substantial area of said device illuminated in proportion to the number of remaining operable light elements to the total light elements of said array.
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23. An integrated illumination device comprising a DSB element in parallel with at least one LED.
Specification