Bi-directional LED-based light

• US 7,053,560 B1
• Filed: 11/17/2003
• Issued: 05/30/2006
• Est. Priority Date: 11/17/2003
• Status: Active Grant

• Current Assignee: Winnie Lai-Ling Ng
• Original Assignee: Dr. Led (Holdings), Inc.
• Inventors: Ng, James K.
• Primary Examiner(s): Lee, Wilson
• Application Number:
  US10/714,761
• Time in Patent Office: 925 Days
• Field of Search: 315/185.R, 315/185.S, 315/200.A, 315/200.R, 315/291, 315/316, 315/312, 315/324, 315/224, 315/307, 315/247, 362/800, 362/231, 362/296
• US Class Current: 315/185.00R
• CPC Class Codes: F21K 9/23 Retrofit light sources for lighting devices with a single fitting for each light source, e.g. for substitution of incandescent lamps with bayonet or threaded fittings
• CPC Class Codes: F21Y 2107/90 on two opposite sides of supports or substrates
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/3574 Emulating the electrical or functional characteristics of incandescent lamps
• CPC Class Codes: H05B 45/42 Antiparallel configurations
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

At least one pair of LEDs, preferably of the super-luminescent type, are connected in parallel but with reverse polarity in series with at least one resistor and driven by a voltage source, which may deliver unrectified alternating current. An array of m series-connected LED pairs may be included in n parallel paths. The printed circuit board in which the LED pair(s) is mounted is adapted to fit into after-market fittings originally intended to receive incandescent light bulbs. In some embodiments, contacts are formed in the edges of lateral protrusions in the PCB.

Claims

1. A lighting arrangement comprising:

a source of electrical power;

m pairs of light-emitting diodes (LEDs), each pair of LEDs including a first LED and a second LED, driven by the power source and connected in parallel in each of n parallel paths such that an anode of the first LED in each pair is electrically connected to a cathode of the second LED in the pair, and an anode of the second LED in each pair is electrically connected to a cathode of the first LED in the pair, one of each pair of LEDs thereby being forward biased to produce light regardless of the instantaneous polarity of electrical current supplied to the LED pair by the power source;

a current-limiting device, connected in series between the power source and each LED pair;

in which;

the m pairs of LEDs in each respective parallel path are connected in series;

the n parallel paths share common power connections but are otherwise electrically separated from each other such that electrical current entering each parallel path passes through the m series-connected LED pairs of only that parallel path; and

m is a predetermined positive integer; and

n is a predetermined positive integer greater than one.

2. An arrangement as in claim 1, further comprising, for each of the n parallel paths, a current-limiting device, connected in series between the power source and the m LED pairs in each respective path.

13. An arrangement as in claim 1, in which the power source supplies unrectified alternating current to each LED pair, whereby only one of the LEDs in each LED pair will be forward biased at any given moment, and heat generated by the plurality of LED pairs is reduced and heat dissipation is increased.

16. An arrangement as in claim 1, in which the LED pair comprises two LED dies mounted with reverse polarity within a single LED casing.

17. An arrangement as in claim 13, in which

a plurality of LED pairs are mounted on a single printed circuit board (PCB) base and the LEDs are separated by no more than 1 mm.

3. A lighting arrangement comprising:

a source of electrical power; and

at least one pair of light-emitting diodes (LEDs) driven by the power source, each pair of LEDs including a first LED and a second LED, and connected in parallel such that an anode of the first one LEDs in each pair is electrically connected to a cathode of the second LED in the pair, and an anode of the second LED in each pair is electrically connected to a cathode of the first LED in the pair, one of each pair of LEDs thereby being forward biased to produce light regardless of the instantaneous polarity of electrical current supplied to the LED pair by the power source;

a printed circuit board (PCB) base having front and rear surfaces and laterally extending side-edge protrusions; and

contact surfaces on edge surfaces of the protrusions;

the PCB base forming a mounting substrate for the LED pairs.

4. An arrangement as in claim 3, in which the protrusions are positioned so as to mate with at least one internal contact surface of a light fixture.

5. An arrangement as in claim 4, in which the light fixture is a screw-in fitting.

6. An arrangement as in claim 4, in which the light fixture is a bayonet fitting.

7. An arrangement as in claim 4, in which the light fixture is a flanged fitting.

8. An arrangement as in claim 4, in which the light fixture is a wedge-based fitting.

9. An arrangement as in claim 4, in which the light fixture is a standard, pre-existing, commercially available fitting designed to receive an incandescent light bulb.

10. An arrangement as in claim 4, further comprising a biasing arrangement that biases the contact surfaces of the protrusions into electrical contact with the internal contact surfaces.

11. An arrangement as in claim 4, further comprising at least one slot in the PCB base forming a region of lateral compression, the PCB base having a width equal to or slightly greater than an internal dimension of the light fixture, compression of the PCB base, upon installation of the PCB base in the fixture, creating a lateral biasing force biasing the contact surfaces of the protrusions into electrical contact with the internal contact surfaces of the fixture.

12. An arrangement as in claim 3, further comprising a separate pair of parallel-connected LEDs on the front and back surfaces of the PCB base, one LED in each pair being forward biased at the same time as a corresponding LED in the other pair, whereby front-and-back illumination is provided by the LED pairs on the single PCB substrate.

14. A lighting arrangement comprising:

a source of electrical power; and

at least one pair of light-emitting diodes (LEDs) driven by the power source, each pair of LEDs including a first LED and a second LED, and connected in parallel such that an anode of the first one LEDs in each pair is electrically connected to a cathode of the second LED in the pair, and an anode of the second LED in each pair is electrically connected to a cathode of the first LED in the pair, one of each pair of LEDs thereby being forward biased to produce light regardless of the instantaneous polarity of electrical current supplied to the LED pair by the power source;

in which;

a plurality of LED pairs are mounted on a single printed circuit board (PCB) base; and

the plurality of LED pairs include at least three pairs producing light of each of three colors, whereby objects illuminated by the arrangement appear to a viewer to be illuminated by full spectrum white light.

15. An arrangement as in claim 14, in which the colors are red, green and blue.

18. A lighting arrangement comprising:

a source of electrical power;

at least one pair of light-emitting diodes (LEDs), each pair of LEDs including a first LED and a second LED;

a current-limiting device, connected in series between the power source and each LED pair;

a printed circuit board (PCB) base having front and rear surfaces and laterally extending side-edge protrusions, the PCB base a mounting substrate for the LED pairs; and

contact surfaces formed on edge surfaces of the protrusions;

in which;

the power source supplies unrectified alternating current to each LED pair;

each LED pair is driven by the power source;

the LEDs in each pair are connected in parallel such that an anode of the first LED in each pair is electrically connected to a cathode of the second LED in the pair, and an anode of the second LED in each pair is electrically connected to a cathode of the first LED in the pair, one of each pair of LEDs thereby being forward biased to produce light regardless of the instantaneous polarity of electrical current supplied to the LED pair by the power source; and

the protrusions are positioned so as to mate with at least one internal contact surface of a fitting designed to receive an incandescent, plasma-based fluorescent or halogen bulb.