LED light string and arrays with improved harmonics and optimized power utilization

• US 20040201988A1
• Filed: 05/06/2004
• Published: 10/14/2004
• Est. Priority Date: 02/12/1999
• Status: Abandoned Application

• Current Assignee: Fiber Optic Designs Incorporated
• Original Assignee: Fiber Optic Designs Incorporated
• Inventors: Allen, David
• Application Number:
  US10/839,335
• Publication Number:
  US 20040201988A1
• Time in Patent Office: Days
• US Class Current: 362/249
• CPC Class Codes: F21S 4/10 with light sources attached to loose electric cables, e.g. Christmas tree lights
• CPC Class Codes: F21W 2121/00 Use or application of lighting devices or systems for decorative purposes, not provided for in codes F21W2102/00 – F21W2107/00
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H05B 45/36 Circuits for reducing or suppressing harmonics, ripples or electromagnetic interferences [EMI]
• 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]

Abstract

An AC driven LED light string assembly is provided possessing reduced harmonic distortion and improved electrical efficiency when one or more series blocks of LED lamps is employed. In one embodiment, there is provided an LED light string employing a capacitor coupled in parallel across the light string AC input, or end connector terminals. According to another embodiment, LED light strings are to be manufactured with a substantially equal number of light strings produced with all LEDs in forward bias (anode first) and reverse bias (cathode first). This allows true randomness when large numbers of single series block LED light strings are connected in an end-to-end manner. It is possible to apply this concept to single LED lamps having two chips where one chip is powered in reverse bias to the second chip; thereby providing self-canceling harmonics within the single LED lamp.

Claims

1. A light string comprising:

a predetermined number of light emitting diodes (LEDs) and sockets forming individual electrical components electrically coupled in series to form at least one series block, each electrical component defining individual alternating current average drive voltages, the at least one series block having a first electrical component and a last electrical component;

an alternating current electrical power supply having an average supply voltage;

means for reducing harmonic distortion in said at least one series block.

2. The light string of claim 1, wherein said means for reducing harmonic distortion comprises a capacitor electrically connected in parallel across one of the alternating current power supply and an end connector terminal.

3. The light string of claim 1, wherein said means for reducing harmonic distortion comprises an arrangement of said individual electrical components where a first set of said individual electrical components is oriented in a forward bias position and a second set of said individual electrical components is oriented in a reverse bias position, said first set being substantially equal in number to said second set.

4. The light string of claim 3, wherein said first set and said second set are coupled in series within a single series block of said at least one series block.

5. The light string of claim 3, wherein said first set and said second set define individual series blocks electrically connected to improve power utilization and reduce harmonic distortion.

6. The light string of claim 1, wherein said means for reducing harmonic distortion comprises an arrangement of said individual electrical components where at least one first set of said individual electrical components is oriented in a positive forward bias position and at least one second set of said individual electrical components is oriented in a negative reverse bias position to at least partly cancel a harmonic effect of said at least one first set.

7. The light string of claim 6, wherein said at least one first set is substantially equal in number to said at least one second set.

8. The light string of claim 6, wherein said at least one first set differs equal in number from said at least one second set by one.

9. The light string of claim 6, wherein said means for reducing harmonic distortion further comprises a capacitor electrically connected in parallel across one of the alternating current power supply and an end connector terminal.

10. The light string of claim 1, wherein the supply voltage (V_rms) follows the following relationship in order to determine the predetermined number of LEDs:

11. The light string of claim 10, where, when, all N_m diodes in the m-th series block are of the same type, each with V_rms, then V_m<

N_mV_avg.

12. The light string of claim 1, further comprising a lamp holder having a keyed offset, the lamp holder fixedly attached to each LED, and

a lamp base having a notch adapted to receive the keyed offset of the lamp holder, thereby mechanically orienting and aligning each LED by its polarity.

13. The light string of claim 14, wherein the lamp base further comprises a base keyed offset and a lamp assembly holder, the lamp assembly holder having a notch adapted to receive the base keyed offset.

14. The light string of claim 3, wherein said arrangement comprises a substantial equal number of chips within each light emitting diodes in reverse bias to each other, thereby providing self-canceling harmonics within the single LED lamp.

25. A method for testing the polarity of the light string of claim 1, comprising the steps of:

illuminating LEDs of said at least one series block oriented in a positive forward bias position;

modifying a number of LEDs in said light string to include additional LEDS oriented in a negative reverse bias position to thereby reduce harmonic distortion of said light string.

15. A light string comprising:

a predetermined number of light emitting diodes (LEDs) and sockets forming individual electrical components electrically coupled in series to form at least one series block, each electrical component defining individual alternating current average drive voltages, the at least one series block having a first electrical component and a last electrical component;

an alternating current electrical power supply having an average supply voltage;

at least one additional circuitry component electrically connected to said at least one series block, said at least one additional circuitry component reducing harmonic distortion and improve power utilization in said at least one series block.

16. The light string of claim 15, wherein said means for reducing harmonic distortion comprises a capacitor electrically connected in parallel across one of the alternating current power supply and an end connector terminal.

17. The light string of claim 15, wherein said means for reducing harmonic distortion comprises an arrangement of said individual electrical components where a first set of said individual electrical components is oriented in a forward bias position and a second set of said individual electrical components is oriented in a reverse bias position, said first set being substantially equal in number to said second set.

18. The light string of claim 17, wherein said first set and said second set are coupled in series within a single series block of said at least one series block.

19. The light string of claim 17, wherein said first set and said second set define individual series blocks electrically connected to improve power utilization and reduce harmonic distortion.

20. The light string of claim 15, wherein said means for reducing harmonic distortion comprises an arrangement of said individual electrical components where at least one first set of said individual electrical components is oriented in a forward bias position and at least one second set of said individual electrical components is oriented in a reverse bias position to at least partly cancel a harmonic effect of said at least one first set.

21. The light string of claim 20, wherein said at least one first set is substantially equal in number to said at least one second set.

22. The light string of claim 20, wherein said at least one first set differs equal in number from said at least one second set by one.

23. The light string of claim 20, wherein said means for reducing harmonic distortion further comprises a capacitor electrically connected in parallel across one of the alternating current power supply and an end connector terminal.

24. The light string of claim 17, wherein said arrangement comprises a substantial equal number of chips within each light emitting diodes in reverse bias to each other, thereby providing self-canceling harmonics within the single LED lamp.