Light tube and power supply circuit

• US 8,866,396 B2
• Filed: 02/26/2013
• Issued: 10/21/2014
• 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, Ivey, John
• Primary Examiner(s): A, Minh D
• Application Number:
  US13/777,331
• Publication Number:
  US 20130169179A1
• Time in Patent Office: 602 Days
• Field of Search: 315307-308, 315/312, 315/246, 315/247, 315/224, 315/185.R, 315/185.S, 362/249.01, 362/249.03, 362/249.02, 362/543, 362/544, 362/548
• US Class Current: 315/200.R
• 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 light tube for illumination by a power supply circuit includes a bulb portion and at least one end cap disposed on the bulb portion. A plurality of light emitting diodes is disposed inside the bulb portion for illuminating in response to electrical current to be received from the power supply circuit. The light emitting diodes are arranged in spaced-apart groupings.

Claims

1. A lighting device connectable to a socket of a light fixture, comprising:

a housing having a first end and a second end, wherein at least a portion of the housing is transparent or translucent;

an end cap disposed on one of the first end or the second end of the housing and configured to fit with the socket; and

a plurality of light emitting diodes disposed inside and extending between the first and second ends of the housing, wherein the plurality of light emitting diodes is arranged to provide light through at least a portion of the transparent or translucent portion of the housing;

wherein

a power source is electrically connected to and configured to provide power to the plurality of light emitting diodes through a pulse width modulation circuit and a current limiting circuit, the current limiting circuit comprising an inductive element coupled between the pulse width modulation circuit and at least some of the plurality of light emitting diodes.

2. The lighting device of claim 1 wherein the end cap is a first end cap disposed on the first end of the housing, the housing comprises an elongate tube and the light fixture is a fluorescent light fixture, the lighting device further comprising:

a second end cap disposed on the second end of the housing, the second end cap configured to fit with the socket.

3. The lighting device of claim 2 wherein the first end cap and the second end cap comprise a respective pair of electrical bi-pin connectors.

4. The lighting device of claim 1 wherein the current limiting circuit is a switching power supply type current limiter.

5. The lighting device of claim 1 wherein the pulse width modulation circuit and the current limiting circuit are packaged inside the housing.

6. The lighting device of claim 1 wherein the pulse width modulation circuit and the current limiting circuit are packaged inside the socket.

7. The lighting device of claim 1 wherein the power source is an AC power source or a DC power source and a rectifier is electrically connected to the AC power source to receive AC input and electrically connected to the pulse width modulation circuit to provide DC output to the pulse width modulation circuit when the power source is the AC power source.

8. The lighting device of claim 7 wherein the rectifier receives the AC input from a conventional fluorescent ballast electrically connected to the AC power source.

9. The lighting device of claim 7 wherein the power source is a DC power source in the form of a battery, the battery providing the DC output to the pulse width modulation circuit.

10. The lighting device of claim 1 wherein the pulse width modulation circuit is configured to switch DC power to the plurality of light emitting diodes on and off at a frequency that causes the light emitted from the plurality of light emitting diodes to appear, when viewed by a human eye, to shine continuously.

11. The lighting device of claim 1 wherein the pulse width modulation circuit modulates a frequency of light emitted from the plurality of light emitting diodes above a nominal variation of 120 to 100 Hz.

12. The lighting device of claim 1 wherein the pulse width modulation circuit modulates a frequency of light emitted from the plurality of light emitting diodes to provide a visible on and off cycle.

13. The lighting device of claim 1 wherein the end cap is coupled to the power source through a magnetic link.

14. The lighting device of claim 13 wherein the magnetic link comprises an inductive transmitter and an inductive receiver.

15. The lighting device of claim 1, further comprising:

a circuit board mounted within the housing, and wherein the light emitting diodes are arranged such that the radiation pattern of light emitted therefrom is centered at a 90°

angle relative to the circuit board.

16. The lighting device of claim 15 wherein the plurality of light emitting diodes are mounted on only one side of the circuit board.

17. The lighting device of claim 15 wherein the circuit board has an H-shaped cross-section when viewed from the first end of the housing.

18. A lighting device connectable to a socket of a light fixture, comprising:

a housing having a first end and a second end, wherein at least a portion of the housing is light-transmissive;

an end cap disposed on one of the first end or the second end of the housing and configured to fit with the socket; and

a plurality of light emitting diodes disposed inside and extending between the first and second ends of the housing, wherein the plurality of light emitting diodes is arranged to provide light through at least a portion of the light-transmissive portion of the housing;

a pulse width modulation circuit configured to receive power from a power source; and

a current limiting circuit comprising an inductive element coupled between the pulse width modulation circuit and at least some of the plurality of light emitting diodes.

19. The lighting device of claim 18 wherein the end cap is a first end cap disposed on the first end of the housing, the housing comprises an elongate tube and the light fixture is a fluorescent light fixture, the lighting device further comprising:

a second end cap disposed on the second end of the housing, the second end cap configured to fit with the socket, wherein the first end cap and the second end cap comprise a respective pair of electrical bi-pin connectors.

20. The lighting device of claim 18 wherein the pulse width modulation circuit and the current limiting circuit are packaged inside the housing.