Light tube and power supply circuit

• US 9,803,806 B2
• Filed: 12/08/2016
• Issued: 10/31/2017
• Est. Priority Date: 02/11/2000
• Status: Expired due to Fees

• Current Assignee: Ilumisys Incorporated (Altair Engineering Incorporated)
• Original Assignee: Ilumisys Incorporated (Altair Engineering Incorporated)
• Inventors: Timmermans, Jos, Raymond, Jean C., Ivey, John
• Primary Examiner(s): Ton, Anabel
• Application Number:
  US15/373,349
• Publication Number:
  US 20170089520A1
• Time in Patent Office: 327 Days
• CPC Class Codes: B60Q 3/80 Circuits; Control arrangements for dashboards B60Q3/16; for mass transit vehicles B60Q3/47
• CPC Class Codes: F21K 9/272 Details of end parts, i.e. the parts that connect the light source to a fitting; Arrangement of components within end parts F21K9/278 takes precedence
• CPC Class Codes: F21K 9/275 Details of bases or housings, i.e. the parts between the light-generating element and the end caps; Arrangement of components within bases or housings F21K9/278 takes precedence
• CPC Class Codes: F21K 9/278 Arrangement or mounting of circuit elements integrated in the light source
• CPC Class Codes: F21K 9/60 Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
• CPC Class Codes: F21K 9/66 Details of globes or covers forming part of the light source
• CPC Class Codes: F21K 9/90 Methods of manufacture
• CPC Class Codes: F21S 4/28 rigid, e.g. LED bars
• CPC Class Codes: F21V 15/015 Devices for covering joints between adjacent lighting devices; End coverings
• CPC Class Codes: F21V 19/003 Fastening of light source holders, e.g. of circuit boards or substrates holding light sources
• CPC Class Codes: F21V 19/008 of straight tubular light sources, e.g. straight fluorescent tubes, soffit lamps
• CPC Class Codes: F21V 23/00 Arrangement of electric circuit elements in or on lighting devices characterised by cooling arrangements F21V29/508
• CPC Class Codes: F21V 23/009 the casing being inside the housing of the lighting device
• CPC Class Codes: F21V 23/02 the elements being transformers, impedances or power supply units, e.g. a transformer with a rectifier
• CPC Class Codes: F21V 23/023 Power supplies in a casing F21V23/003 takes precedence
• CPC Class Codes: F21V 23/06 the elements being coupling devices , e.g. connectors
• CPC Class Codes: F21V 3/02 characterised by the shape
• CPC Class Codes: F21Y 2103/10 comprising a linear array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 25/13 the devices being of a type provided for in group H01L33/00
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H05B 45/10 : Controlling the intensity of the light
• CPC Class Codes: H05B 45/14 : using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/325 : Pulse-width modulation [PWM]
• CPC Class Codes: H05B 45/3578 : Emulating the electrical or functional characteristics of discharge lamps
• CPC Class Codes: H05B 45/3725 : Switched mode power supply [SMPS]
• CPC Class Codes: H05B 47/10 : Controlling the light source
• CPC Class Codes: Y02B 20/30 : Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

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.

Claims

1. A method for providing a light tube for mounting within a conventional fluorescent light tube socket, the method comprising:

disposing the plurality of light emitting diodes on a rigid support structure;

disposing the support structure and plurality of light emitting diodes within an tubular housing comprising a transmissive cover for the light emitting diodes;

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 provide power to the plurality of light emitting diodes during operation of the light tube;

disposing a pair of end caps at opposite ends of the bulb portion, each end cap configured to fit with the conventional fluorescent light tube socket; and

packaging at least a portion of the power supply circuit inside at least one of the end caps.

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 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.

8. The method of claim 7, wherein the rectifier is arranged to provide the DC output to a pulse width modulator during operation of the light tube.

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

10. The method of claim 9, further comprising electrically connecting the power supply circuit to the bi-pin connector of at least one end cap.

11. 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.

12. The method of claim 11, wherein covering the rigid support structure comprises disposing the support structure within the tubular housing comprising the transmissive cover for the light emitting diodes.

13. The method of claim 12, 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.

14. The method of claim 13, 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.

15. The method of claim 13, 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.

16. The method of claim 13, wherein the planar portion is integral with the sidewalls.

17. The method of claim 13, wherein the sidewalls are generally perpendicular to the planar portion.

18. The method of claim 11, wherein the support structure comprises a circuit board and the light emitting diodes are mounted on a surface of the circuit board.

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

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

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

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

23. 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.