# US 9,752,736 B2 · Light tube and power supply circuit

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- Number: US 9,752,736 B2
- Document ID: US9752736B2
- Status: Granted
- Kind: B2
- Application number: 15/373,356
- Filed: 2016-12-08
- Published: 2017-04-20
- Granted: 2017-09-05
- Earliest claimed: 2000-02-11
- Assignees: iLumisys, Inc.
- Applicants: iLumisys, Inc.
- Inventors: Jos Timmermans; Jean C. Raymond; John Ivey
- Web page: https://patentgrep.com/patent/US9752736B2

## CPC

- H05B 47/10: Controlling the light source
- B60Q 3/80: Circuits; Control arrangements (for dashboards B60Q3/16; for mass transit vehicles B60Q3/47)
- 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)
- 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)
- F21K 9/278: Arrangement or mounting of circuit elements integrated in the light source
- F21K 9/60: Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
- F21K 9/66: Details of globes or covers forming part of the light source
- F21K 9/90: Methods of manufacture
- F21S 4/28: rigid, e.g. LED bars
- F21V 3/02: characterised by the shape
- F21V 15/015: Devices for covering joints between adjacent lighting devices; End coverings
- F21V 19/003: {Fastening of light source holders, e.g. of circuit boards or substrates holding light sources}
- F21V 23/00: Arrangement of electric circuit elements in or on lighting devices {(characterised by cooling arrangements F21V29/508)}
- F21V 23/009: {the casing being inside the housing of the lighting device}
- F21V 23/02: the elements being transformers, impedances {or power supply units, e.g. a transformer with a rectifier}
- F21V 23/023: {Power supplies in a casing (F21V23/003 takes precedence)}
- F21V 23/06: the elements being coupling devices {, e.g. connectors}
- H05B 45/14: using electrical feedback from LEDs or from LED modules
- H05B 45/3578: Emulating the electrical or functional characteristics of discharge lamps
- H05B 45/3725: Switched mode power supply [SMPS]
- F21V 19/008: {of straight tubular light sources, e.g. straight fluorescent tubes, soffit lamps}
- F21Y 2103/10: comprising a linear array of point-like light-generating elements
- F21Y 2115/10: Light-emitting diodes [LED]
- H05B 45/10: Controlling the intensity of the light
- H05B 45/325: Pulse-width modulation [PWM]
- H10W 90/00: Package configurations
- Y02B 20/30: Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- B60Q: ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
- F21K: NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
- F21S: NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
- F21V: FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- F21Y: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## 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

### Claim 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, the rigid support structure comprising spaced-apart sidewalls forming 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;
disposing the support structure and plurality of light emitting diodes within a tubular housing comprising a transmissive cover for the light emitting diodes, wherein at least a portion of the sidewalls contact an interior surface of the tubular housing; 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.

### Claim 2 (depends on 1)

The method of claim 1, wherein disposing the plurality of light emitting diodes relative to the light transmissive cover comprises covering the light emitting diodes with the light transmissive cover of the tubular housing.

### Claim 3 (depends on 2)

The method of claim 2, wherein the portion of the sidewalls contact the light transmissive cover when the support structure is disposed within the tubular housing.

### Claim 4 (depends on 1)

The method of claim 1, 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.

### Claim 5 (depends on 1)

The method of claim 1, wherein the planar portion is integral with the sidewalls.

### Claim 6 (depends on 1)

The method of claim 1, wherein the sidewalls are generally perpendicular to the planar portion.

### Claim 7 (depends on 1)

The method of claim 1, wherein the support structure comprises a circuit board and the light emitting diodes are mounted on a surface of the circuit board.

### Claim 8 (depends on 1)

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.

### Claim 9 (depends on 1)

The method of claim 1, further comprising connecting a power supply circuit to the plurality of light emitting diodes and disposing the power supply circuit within the light tube.

### Claim 10 (depends on 9)

The method of claim 9, 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.

### Claim 11 (depends on 9)

The method of claim 9, 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.

### Claim 12 (depends on 11)

The method of claim 11, 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.

### Claim 13 (depends on 9)

The method of claim 9, 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.

### Claim 14 (depends on 9)

The method of claim 9, wherein at least some components of the power supply circuits are disposed within at least one of the end caps.

### Claim 15 (depends on 9)

The method of claim 9, 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.

### Claim 16 (depends on 15)

The method of claim 15, wherein the rectifier is arranged to provide the DC output to a pulse width modulator during operation of the light tube.

### Claim 17 (depends on 1)

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

### Claim 18 (depends on 17)

The method of claim 17, further comprising connecting a power supply circuit to the plurality of light emitting diodes and electrically connecting the power supply circuit to the bi-pin connector of at least one end cap.

### Claim 19 (depends on 1)

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

### Claim 20 (depends on 1)

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

### Claim 21 (depends on 1)

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

### Claim 22 (depends on 1)

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

### Claim 23 (depends on 1)

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.