US 6,459,218 B2 · Inductively powered lamp unit

Abstract

An inductively powered lamp unit 806 is fixed onto a substrate and over a position where a primary inductive loop 803 is spread apart (as at 807). At such sites, a horizontal (or at least parallel to the surface of the substrate) component of alternating magnetic flux is available. The conductors of the loop 802-803 can be inserted in a slit 804 cut into the substrate. The spreading apart of the conductors may be ensured with a spreader 808. A power supply 801 may be a resonant supply operating at 40 kHz. The lamp unit 806 does use a resonant pickup coil which can be shorted so as to minimize coupling, and provide supply regulation. The lamp unit can be controlled by signals transmitted over the primary loop. Applications include roadway markers and fire escape egress indicators, and underwater lighting.

Claims7

Dependent claims

A method of supplying electricity to a discrete lamp unit, comprising the steps of:

forming a hole in stationary material;
positioning in the hole wiring capable of generating an alternating inductive magnetic field outside the hole when an alternating electrical current is passed through the wiring;
covering the wiring in the hole;
and
positioning remote from the wiring the discrete lamp unit which is adapted to provide illumination when energized inductively with an induced alternating electrical current generated by the inductive magnetic field.

2 more elements

A loosely coupled, self-illuminated cat's eye, roadway marking system, comprising:

a power supply for producing an alternating current at at least one selected frequency;
an inductive power distribution cable connected to the power supply, said inductive power distribution cable being a loop with two conductors positioned one above the other in a substantially vertical slit in a roadway to be marked;
and
at least one road warning lamp unit located above or close to said power distribution cable, each lamp unit comprising,
a housing having at least one window for transmitting light,
one or more light emitting diodes for radiating light, and collection means to collect loosely coupled inductively transferred power from an external alternating primary magnetic field from the inductive power distribution cable operating at the at least one selected frequency, said collection means comprising a resonant circuit within the housing having a resonant period corresponding to a selected frequency and including at least one inductance and at least one capacitance, the at least one inductance having a winding adapted to be intersected by a portion of the alternating magnetic field and thereby being for collecting power as a secondary current,
means for limiting the maximum amount of secondary current circulating in the resonant circuit,
means for transferring power at an output from the resonant circuit to the lamp or lamps, and
means for controlling the power provided to the lamp or lamps.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application

09/780,517Filed 12 Feb 2001 · continuation

Priority

NZ 26400013 Jul 1994

Published

US 2002/0008973 A124 Jan 2002

Granted

1 Oct 2002

Term ends

Not estimatedThe source records don’t support an estimate.

Classification20 codes

F21S 8/032
Of surface-mounted type: the surface being a floor or like ground surface, e.g. pavement
E01F 9/559
Low discrete bodies, e.g. marking blocks, studs or flexible vehicle-striking members: illuminated
F21S 4/28
With light sources held by or within elongate supports: rigid, e.g. LED bars
F21V 23/02
Arrangement of electric circuit elements in or on lighting devices: the elements being transformers, impedances or power supply units, e.g. a…

Inductively powered lamp unit

Life of this patent

Inductively powered lamp unit

Life of this patent

Abstract

Claims7