05936599 is referenced by 222 patents and cites 41 patents.

An LED array circuit includes a number of series connected LED pairs, each pair including two parallel connected oppositely polarized LEDS. The array is coupled to a standard AC voltage source in series with an inductor L having Q>5 and a reactance which is equivalent to the resistance of a current limiting resistor. The use of an inductor in place of a resistor increases the efficiency of the array to approximately 80%. The efficiency of the array is increased even further by coupling a capacitor parallel to the array and by tuning the inductor and capacitor to the frequency of the AC voltage source. According to one embodiment of the invention, a somg;e retro-fittable unit is provided wherein an inductor, a capacitor, and an array of LEDs are contained in a housing having substantially the same size and shape as a standard incandescent bulb or the lens/filter used in a traffic signal display. According to another embodiment of the invention, a single module is provided with a plurality of LED arrays, with each LED array having its own capacitor coupled in parallel thereto, and its own series coupled switch. The module is coupled to and across the AC voltage source, with one node of the module coupled to the AC voltage source by an inductor.

Title
AC powered light emitting diode array circuits for use in traffic signal displays
Application Number
379973
Publication Number
5936599
Application Date
May 13, 1998
Publication Date
August 10, 1999
Inventor
Welles Reymond
380 Hitchock Rd, #84, Waterbury, 06705
CT, US
Agent
Thomas A Gallagher
David S Jacobson
David P Gordon
IPC
G09G 3/36
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