LED-BASED LIGHTING SYSTEM FOR RETROFITTING FLUORESCENT LIGHTING FIXTURES IN A TRANSIT VEHICLE
First Claim
1. An LED-based lighting unit for retrofitting a fluorescent light fixture in a transit vehicle, the LED-based lighting unit comprising:
- an elongate fixture frame securably attachable within a fluorescent lighting fixture cavity of a transit vehicle, said cavity having left and right electrical sockets for supporting and providing power to a fluorescent tube light, wherein the elongate fixture frame substantially conforms to the shape of the cavity so that it fits snugly therein;
left and right pins extending from the elongate fixture frame, said left and right pins securably attaching the elongate fixture frame to the left and right sockets within the fluorescent lighting fixture cavity;
a heat conductive mounting surface on the elongate fixture frame;
a plurality of light-emitting diodes (LEDs) disposed along a length of said heat conductive mounting surface, for illuminating an interior area of the transit vehicle; and
a diffusive lens cover removably attachable to an output opening of the fluorescent lighting fixture cavity.
1 Assignment
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Accused Products
Abstract
An LED-based lighting unit for retrofitting a fluorescent light fixture in a transit vehicle has a concave frame or structure conforming to the shape of the fluorescent lighting fixture cavity, connector pins on either end of the frame for secure attachment to sockets of the fluorescent fixture, a plurality of LED modules for illuminating an area of a transit vehicle, a power adapter for receiving and converting an input power supply signal, and a diffusive lens cover. The frame may have rear fins or other features for facilitating dissipation of heat generated by the LEDs. A controller adjusts the intensity of the LEDs based on a reading from a temperature sensor and on a manual brightness setting. The change in light output may be accomplished by reducing a duty cycle of a pulse width modulated (PWM) waveform supplying the LEDs.
144 Citations
32 Claims
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1. An LED-based lighting unit for retrofitting a fluorescent light fixture in a transit vehicle, the LED-based lighting unit comprising:
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an elongate fixture frame securably attachable within a fluorescent lighting fixture cavity of a transit vehicle, said cavity having left and right electrical sockets for supporting and providing power to a fluorescent tube light, wherein the elongate fixture frame substantially conforms to the shape of the cavity so that it fits snugly therein; left and right pins extending from the elongate fixture frame, said left and right pins securably attaching the elongate fixture frame to the left and right sockets within the fluorescent lighting fixture cavity; a heat conductive mounting surface on the elongate fixture frame; a plurality of light-emitting diodes (LEDs) disposed along a length of said heat conductive mounting surface, for illuminating an interior area of the transit vehicle; and a diffusive lens cover removably attachable to an output opening of the fluorescent lighting fixture cavity. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for retrofitting a fluorescent light fixture in a transit vehicle with an LED-based lighting system, the method comprising:
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removing a fluorescent tube light from a fluorescent lighting fixture cavity in a transit vehicle, said cavity having left and right electrical sockets for supporting and providing power to the fluorescent tube light; disconnecting incoming power to said left and right electrical sockets; securably attaching an elongate fixture frame within the fluorescent lighting fixture cavity, said the elongate fixture frame substantially conforming to the shape of the cavity so that it fits snugly therein and having left and right pins extending from either end of the elongate fixture frame, said left and right pins being thereby disposed within the left and right sockets of the fluorescent lighting fixture cavity to provide support for said elongate fixture frame; and attaching a removable diffusive lens cover to an opening of the fluorescent lighting fixture cavity; wherein said elongate fixture frame comprises a heat conductive mounting surface on the elongate fixture frame and a plurality of light-emitting diodes (LEDs) disposed along a length of said heat conductive mounting surface for illuminating an interior area of the transit vehicle. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. An LED-based lighting fixture for a transit vehicle, comprising:
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an elongate fixture frame securably attachable within a concave fluorescent lighting fixture cavity of a transit vehicle, the elongate fixture frame substantially conforming to the cavity such that it fits snugly therein; a heat conductive mounting surface on the elongate fixture frame; a plurality of light-emitting diodes (LEDs) disposed along a length of said heat conductive mounting surface, for illuminating an interior area of the transit vehicle; a temperature sensor in thermal communication with said heat conductive mounting surface; and a control circuit adapted to receive a temperature reading from said temperature sensor, said control circuit adjusting a voltage signal supplied to said LEDs in order to reduce an intensity of light output from said LEDs when the temperature reading exceeds a first predetermined threshold. - View Dependent Claims (31, 32)
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Specification