WO2009156969A2

WO2009156969A2 - An led lamp

Info

Publication number: WO2009156969A2
Application number: PCT/IB2009/052769
Authority: WO
Inventors: Otto Horlacher
Original assignee: Otto Horlacher
Priority date: 2008-06-27
Filing date: 2009-06-26
Publication date: 2009-12-30
Also published as: ZA201000936B; WO2009156969A3

Abstract

The invention provides an MR16 compatible LED lamp. The lamp has a power line connectable to the transformer of an existing MR16 installation and having suitable LED electronic control circuitry provided therein spaced apart from the lamp. A releasable clip-set connection in the power line is provided between the lamp and the control circuitry. The lamp has a heat sink suitably configured to fit into an MR16 fixture and the power line extends through the heat sink and through a printed circuit board. The heat sink is made of anodized aluminum. The lamp has a collimator with a lens remote from the printed circuit board and secured in relation to the printed circuit board by a screw-threaded connector extending through the lens. In one embodiment, the heat sink includes a protrusion having a pair of oppositely disposed parallel grooves, transverse to the length of the protrusion to engage between flexibly resilient fingers of a clip in an MR16 fixture. The invention extends to an MR16 lighting installation which includes a power supply connected through a transformer to a power line leading to a light fixture, the power line having suitable LED electronic control circuitry provided therein spaced apart from the fixture.

Description

AN LED LAMP

FIELD OF THE INVENTION

This invention relates to a light emitting diode (LED) lamp and more particularly to such a lamp which is interchangeable with lamps known in the lighting industry as "MR16". The lamps to which the invention relates will be referred to as "MR16 compatible LED lamps".

BACKGROUND TO THE INVENTION

MR16 is a standard format for halogen reflector lamps. The "MR" stands for "multifaceted reflector". The number "16" represents the diameter at the front end of the lamp as a number of eighths of an inch (i.e. 16/8 or 2 inches).

The MR16 lamps are made by a number of manufacturers. These lamps are well suited to a variety of applications that require directional lighting. Their compact size enables the use of smaller and more discreet fittings or fixtures compared to earlier incandescent bulbs. A significant number of lighting installations with MR16 lamp fixtures have been installed in buildings - commercial and residential. MR16 compatible LED lamps are also available. They are similar in shape to halogen MR16 lamps and can be used in most MR16 fixtures. The same interchangeability occurs with MR11 compatible LED lamps - these are to be included in this specification where the MR16 compatible LED lamps are referred to but with their different power references.

There is a wide variety of such interchangeable LED lamps and they are generally a lot less light efficient than the halogen MR16s which can produce up to 900 lumens in a 50 Watt configuration. These LED lamps are frequently used as retrofit products which offer a drop from 50 Watts to about 1 to 9 Watts but this may be accompanied by a reduction in light output of up to about 85%.

This is often a problem in a multi-lamp installation where a building has originally been fitted with MR16 fixtures based on light requirements which can not be met with LED retrofits.

OBJECT OF THE INVENTION

It is an object of this invention to provide an MR16 compatible LED lamp which will allow for at least partially improved efficiency and other improvements.

SUMMARY OF THE INVENTION

In accordance with the invention, there is provided MR16 compatible LED lamp comprising an array of LEDs mounted on and connected to a power supply line through a printed circuit board, the power line connectable to a transformer of an existing MR16 installation and having suitable LED electronic control circuitry provided therein spaced apart from the lamp.

The invention further provides for there to be a releasable clip-set connection in the power line between the lamp and the control circuitry; and for there to be a heat sink suitably configured to fit into an MR16 fixture mounted on the opposite side of the printed circuit board to the LEDs.

Further features of this invention for the power line to extend through the heat sink and through the printed circuit board for connection to the printed circuit board; for the heat sink to have a disc-shaped base secured against the printed circuit board and for the power line to extend through a slot in the edge of the base; and for the printed circuit board to be circular with an opening through which the power line extends.

The invention also provides for the heat sink to be made of anodized aluminum and for the anodizing to be black.

Still further features of this invention provide for the lamp to have a collimator with a lens remote from the printed circuit board and secured in relation to the printed circuit board by a screw-threaded connector extending through the lens.

The invention further provides for the connector to have a head which locates against the lens and to extend through the printed circuit board to engage in a screw-threaded bore provided in the heat sink.

Further features of the invention provide for the connector to include a spacer having a screw-threaded shank locatable through an opening in the printed circuit board at one end and a screw-threaded bore at the other end to receive a screw extending from the head which is locatable through the opening in the lens.

A further aspect of this invention provides for the heat sink to include a protrusion extending away from the printed circuit board and having a pair of oppositely disposed parallel grooves, transverse to the length of the protrusion to engage between flexibly resilient fingers of a clip in an MR16 fixture. The invention further provides for the heat sink to have a base locatable against the printed circuit board and for the protrusion to be a separate component with a screw-threaded bore for engagement with the screw-threaded connector.

In accordance with still another aspect of the invention there is provided an MR16 lighting installation which includes a power supply connected through a transformer to a power line leading to a light fixture, the power line having suitable LED electronic control circuitry provided therein spaced apart from the fixture.

BRIEF DESCRIPTION OF THE DRAWING

These and other features of the invention will be described, by way of examples only, with reference to the accompanying drawings in which:

Figure 1 : shows a MR16 compatible LED lamp with control circuitry separate from the circuit board;

Figure 2: shows a partially exploded perspective view of the MR16 compatible LED lamp and heat sink in Figure 1 ;

Figure 3: shows an exploded perspective view of an alternative MR16 compatible; and

Figure 4: shows a bottom perspective view of the lamp in Figure 3 in assembled condition.

DETAILED DESCRIPTION OF THE INVENTION

Referring to Figures 1 and 2, an LED lamp (1 ) that is MR16 compatible is shown. The lamp (1 ) includes an array of three high powered LEDs mounted on a printed circuit board (3). Each LED is located behind a collimator lens (2). The board (3) has only conductive pathways connecting electric cables (4.1 ) from a power line (4.2) to the LEDs. No electronic components are present on the board (3).

The collimators (2) are part of a lens assembly (5) which is supported in front of the LEDs, on the printed circuit board (3). On the back side of the board (3) is an aluminium heat sink (6).

In one example, the common 12 Volt, 50 Watt halogen MR16 lamps require a magnetic or electronic transformer to convert the 120 or 240 Volt mains voltage to the operating voltage which is required. While these halogen MR16 lamps can usually operate on either AC or DC voltage, LED devices require DC voltage. As such, some kind of rectifier is required if AC current supply is to be used. For this reason, the MR16 compatible LED lamps referred to in the background above are provided with onboard or integral electronic circuitry. Because of the confined space available in many MR16 fixtures, the electronics are usually mounted operatively above and close to the LED arrays of these lamps.

In accordance with the current invention, the power line (4.2) extends via a male/female clip-set connection (7) to an inline electronics control circuitry box

(8). This provides the necessary rectification for the LEDs to operate as required.

More specifically, the electronics box (8) is driving power supply for the LEDs. In this embodiment, it is a constant current LED driver. These drivers are also known as "current regulated power supplies" or "step down switching regulators" for example.

The existing wiring for an MR16 lamp installation will be removed up to the transformer (not shown). The electronics box (8) will be wired into a power line leading from the transformer to a MR16 fitting or fixture in the installation. The printed circuit board (3) is circular and the heat sink (6) has a disc-shaped base (10) which is secured against the board (3) when the lamp (1 ) is assembled - as shown in Figure 1.

The cables (4.1 ) of the power line (4.2) extend through an opening (11 ) in the board (3), for connection to a printed circuit on the operatively lower side of the board (3). A slot (12) in the edge of the base (10) is lined up with the opening (11 ) to accommodate the cables (4.1 ).

The configuration of these components (3) and (6), providing a passage for the power line (4.1 ), enables economical use of the space available in an MR16 light fitting or fixture.

The heat sink (6) is cast from aluminium. Extending upwardly from the base (10) is a plurality of tapered, frusto-conical protrusions (13).

The protrusions (13) provide a surface area suited for heat transfer to dissipate the heat from the LEDs. The heat sink is preferably anodized black, and to a thickness of 16 microns. The anodized aluminium provides more efficient heat dissipation. This in turn provides for an improved MR16 compatibility lamp. The sink may also be anodized with another colour.

To obtain light equivalent or closer to that of a conventional halogen MR16 lamp, it is necessary to drive the LEDs at optimal current. This in turn results in relatively high levels of heat. The heat is detrimental to the integral electronics on MR16 compatible LED lamps. The electronics eventually fail as a result of the heat. The full advantage of longer life expectancy associated with LEDs is lost.

The LED lamp arrangement of the current invention allows for the beneficial use of the most powerful LEDs for the retrofit lamp (1 ). The inline electronics box (8) is spaced apart from the LED lamp (1 ) to avoid direct exposure to the heat from the LEDs (2).

The electronic circuitry (8) will have a life expectancy unaffected by heat and will also be reused if the LED lamp is changed. The LED lamps without integral circuitry will be cheaper and simpler to manufacture.

The product is particularly suited for the refurbishment-to-refurbishment cycle of most commercial properties.

A pin connector (not shown) of the same configuration as the contact pins on an MR16 lamp can be fitted to the cable for connection into an existing installation.

Importantly, the invention provides an energy efficient LED alternative to MR16 lamps which enables sustainable emission of suitable levels of light. The same would apply to MR11 lamps.

Referring to Figures 3 and 4, an alternative MR16 compatible LED lamp is indicated generally by reference numeral (101 ). The lamp has three LEDs mounted on a printed circuit board (102). A lens assembly (103) includes three collimator lenses (104) which are secured thereto, for each of the LEDs.

Also provided on the lens assembly (103) are three supports (105). These supports (105) are usually glued into corresponding apertures (106) in the printed circuit board (102). This is to secure the lens assembly (103) and its collimators in position over the LEDs on the printed circuit board (102). However, the arrangement does not always provide a sufficient connection.

A heat sink (107) is provided as two components. A base (108) with heat dissipating formations (109) around its periphery is locatable against the printed circuit board (102). A protrusion (110) is in turn securable against the base (108), extending to the side opposite to the printed circuit board (102) at the centre of the base (108). Both components are cast from aluminium and anodized black.

The lens (103) and printed circuit board (102) both have centrally located openings. The opening in the lens is numbered (1 11 ) and the one in the printed circuit board, (112). The heat sink base (108) has a corresponding opening and the protrusion (110) has a centrally located screw-threaded bore. The opening in the base (108) and screw-threaded bore cannot be seen in the drawings.

A connector (113) is provided as a spacer (114) with a screw-threaded shank

(115) at one end. In the opposite end of the spacer (114) is provided a screw- threaded bore (not shown). The connector (113) includes a screw (116) which is securable in the bore (not shown).

The shank (115) is fitted with a washer (117) and passed through the openings in the printed circuit board (102) and base (108). The heat sink protrusion (110) and shank (115) are then screwed into engagement with each other. The lens (103) and collimator (104) are fitted over the printed circuit board (102) and the screw

(116) secured to the spacer (114), fastening the lens (103) in place.

The protrusion (110) is provided with a pair of oppositely disposed grooves (118) adjacent its free end.

There are two widely used mechanisms for securing lamps in MR16 fixtures or fixtures. The one involves an internal circular clip, which is removably locatable at the opening of a fixture to hold the lamp inside. The heat sink described with reference to Figures 1 and 2 is limited for use with such a mechanism.

The other mechanism referred to has a pair of flexibly resilient arms which are supported inside the fixture. The MR16 lamps usually have a pair of spaced apart pins at their inner end which are pressed into a pair of corresponding openings fitted with electrical contacts. The arms of the fastening mechanism extend forwardly to engage in grooves on the body of an MR16 lamp when the pins are inserted. The grooves (118) on the heat sink (107) of this embodiment of the invention (shown in Figures 3 and 4) serve the same purpose.

It will be appreciated that the shank on the connector could equally be used with a heat sink as disclosed in the first embodiment (from Figures 1 and 3) or with one of some other description - all that is required is a suitably positioned screw- threaded aperture in the heat sink for engagement with the shank.

The connector may be varied or simplified. For example, a screw-threaded shaft could be used to engage the aperture in the heat sink and a nut on the other side of the lens. Alternatively, a screw of suitable length can extend from the lens into an aperture in the heat sink. In both cases, a sleeve can be used as a spacer between the lens and printed circuit board.

Claims

1 . An MR16 compatible LED lamp comprising an array of LEDs mounted on a printed circuit board and connected to a power supply line through the printed circuit board, the power line connectable to a transformer of an existing MR16 installation and having suitable LED electronic control circuitry provided therein spaced apart from the lamp.

2. A lamp as claimed in claim 1 in which a clip-set connection is provided in the power line between the lamp and the control circuitry.

3. A lamp as claimed in claim 1 or claim 2 in which a heat sink suitably configured to fit into an MR16 fixture is mounted on the opposite side of the circuit board to the LEDs.

4. A lamp as claimed in any one of claims 1 to 3 in which the power line extends through the heat sink and through the printed circuit board for connection to the printed circuit board.

5. A lamp as claimed in claim 4 in which the heat sink has a disc-shaped base secured to the printed circuit board and the power line extends through a slot in the edge of the base.

6. A lamp as claimed in claim 4 or claim 5 in which the printed circuit board is circular and has an opening through which the power line extends.

7. A lamp as claimed in any one of claims 3 to 6 in which the heat sink is made of dark coloured anodized aluminum.

8. A lamp as claimed in any one of the preceding claims having a collimator with a lens remote from the printed circuit board and secured in relation to the printed circuit board by a screw threaded connector that extends through an opening in the lens.

9. A lamp as claimed in claim 8 in which the connector has a head which locates against the lens and extends through the circuit board to engage in a screw-threaded bore provided in the heat sink.

10. A lamp as claimed in claim 9 in which the connector includes a spacer having a screw-threaded shank located through an opening in the printed circuit board at one end and a screw-threaded bore at the other end engaged by a screw which is located through an opening in the lens.

1 1 . A lamp as claimed in any one of claims 3 to 10 in which the heat sink includes a protrusion extending away from the printed circuit board and has a pair of oppositely disposed parallel grooves located transverse to the length of the protrusion to engage a clip in a MR16 fixture.

12. A lamp as claimed in claim 1 1 in which the protrusion is a separate component having a screw-threaded bore for engagement by the screw- threaded connector.

13. An MR16 lighting installation which includes a power supply connected through a transformer to a power line leading to a light fixture, the power line having suitable LED electronic control circuitry provided therein spaced apart from the fixture.

14. A lamp as claimed in claim 2 for use in an installation as claimed in claim 13.