Light tube and power supply circuit

Patent metadata

Field	Value
Publication number	US-9970601-B2
Application number	US-201615372082-A
Country	US
Kind code	B2
Filing date	Dec 7, 2016
Priority date	Feb 11, 2000
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

A replacement light tube for replacing a fluorescent light tube includes a bulb portion extending between a first end and a second end, the bulb portion comprising a support structure, a plurality of white light emitting diodes (LEDs) and an elongate light-transmissive cover. The support structure has a first surface extending between the first end and the second end. The plurality of LEDs are supported by the first surface and arranged between the first end and the second end. The elongate light-transmissive cover extends between the first end and the second end and over the first surface of the support structure. A first end cap and a second end cap are disposed on the first end and the second end, respectively, each configured to fit with a socket for a fluorescent light tube. A power supply circuit is configured to provide power to the plurality of LEDs. The plurality of LEDs are arranged to emit light through the elongate light-transmissive cover and at least a portion of the power supply circuit is packaged inside at least one of the end caps.

First claim

What is claimed is:

1. A method for providing a light tube for mounting within a conventional fluorescent light tube socket, the method comprising:
disposing a plurality of light emitting diodes within a tubular housing comprising a light transmissive cover;
connecting a power supply circuit to the plurality of light emitting diodes, the power supply circuit being configured to receive power from a power source and regulate an intensity of light emitted from the plurality of light emitting diodes during operation of the light tube;
disposing the power supply circuit within the light tube; and
disposing a pair of end caps at opposite ends of the tubular housing, each end cap configured to fit with the conventional fluorescent light tube socket.

2. The method of claim 1 , wherein the power supply circuit is configured to regulate the intensity of light emitted from the plurality of light emitting diodes to compensate for voltage fluctuations from the power source during operation of the light tube.

3. The method of claim 1 , wherein the power supply circuit is configured to regulate the intensity of light emitted from the plurality of light emitting diodes to compensate for ambient temperature changes during operation of the light tube.

4. The method of claim 1 , wherein the power supply circuit comprises a pulse width modulator configured to receive the power from the power source and provide regulated power to the light emitting diodes by pulse-width modulating the received power during operation of the light tube.

5. The method of claim 4 , wherein the power supply circuit comprises a current limiter having an inductive element electrically coupled between the pulse width modulator and at least some of the plurality of light emitting diodes, the current limiter configured to receive power from the pulse width modulator and to transmit power to the at least some of the plurality of light emitting diodes during operation of the light tube.

6. The method of claim 1 , wherein the power supply circuitry is configured to switch power to the plurality of light emitting diodes on and off at a frequency and to cause the light emitted from the plurality of light emitting diodes to appear, when viewed by a human eye, to shine continuously during operation of the light tube.

7. The method of claim 1 , wherein at least some components of the power supply circuits are disposed within at least one of the end caps.

8. The method of claim 1 , wherein the power supply circuit comprises a rectifier configured to receive alternating current (AC) input and to provide direct current (DC) output during operation of the light tube.

9. The method of claim 8 , wherein the rectifier is arranged to provide the DC output to a pulse width modulator during operation of the light tube.

10. The method of claim 1 , wherein each end cap comprises a bi-pin connector for connecting with the conventional fluorescent light tube socket.

11. The method of claim 10 , further comprising electrically connecting the power supply circuit to the bi-pin connector of at least one end cap.

12. The method of claim 1 , wherein disposing the plurality of light emitting diodes relative to the light transmissive cover comprises disposing the plurality of light emitting diodes on a rigid support structure and covering the light emitting diodes with the light transmissive cover of the tubular housing.

13. The method of claim 12 , wherein covering the rigid support structure comprises disposing the support structure within the tubular housing comprising the transmissive cover for the light emitting diodes.

14. The method of claim 13 , wherein the rigid support structure comprises spaced-apart sidewalls defining a channel and a planar portion having a first surface extending in the channel formed by the sidewalls, the light emitting diodes being disposed on the first surface.

15. The method of claim 14 , wherein at least a portion of the sidewalls contact an interior surface of the tubular housing when the support structure is disposed within the tubular housing.

16. The method of claim 14 , wherein, when disposed within the tubular housing, the support structure divides the tubular housing into a first space in which the plurality of light emitting diodes are housed and a second space defined by the planar portion, the sidewalls and the interior surface of the tubular housing.

17. The method of claim 14 , wherein the planar portion is integral with the sidewalls.

18. The method of claim 14 , wherein the sidewalls are generally perpendicular to the planar portion.

19. The method of claim 12 , wherein the support structure comprises a circuit board and the light emitting diodes are mounted on a surface of the circuit board.

20. The method of claim 1 , wherein the light emitting diodes are arranged along an axis extending between the end caps.

21. The method of claim 1 , wherein the light emitting diodes are white light emitting diodes.

22. The method of claim 1 , wherein the light transmissive cover is a tube formed from a transparent or translucent material.

23. The method of claim 1 , wherein the tubular housing is a cylindrical tube.

24. The method of claim 1 , wherein the light emitting diodes comprises a first light emitting diode and a second light emitting diode, the first light emitting diode being the light emitting diode closest to an end of the rigid support structure and the second light emitting diode being the next closest to the end of the rigid support structure, the first and second light emitting diodes being are disposed such that a shortest distance between the first light emitting diode and the second light emitting diode is less than a shortest distance between the first light emitting diode and the end of the rigid support structure.

Assignees

• Ilumisys Inc

Inventors

• Timmermans Jos
• Raymond Jean C
• Ivey John

Classifications

• H10W90/00

  Package configurations · CPC title

• F21K9/90

  Methods of manufacture · CPC title

• F21V23/02

  the elements being transformers, impedances {or power supply units, e.g. a transformer with a rectifier} · CPC title

• F21V19/008

  of straight tubular light sources, e.g. straight fluorescent tubes, soffit lamps · CPC title

• B60Q3/80

  Circuits; Control arrangements (for dashboards B60Q3/16; for mass transit vehicles B60Q3/47) · CPC title