CN211600341U

CN211600341U - Down-spot lamp assembly

Info

Publication number: CN211600341U
Application number: CN201921618131.0U
Authority: CN
Inventors: 安德鲁·约翰逊
Original assignee: Aurora Ltd
Current assignee: Aurora Ltd
Priority date: 2015-12-10
Filing date: 2016-12-15
Publication date: 2020-09-29
Anticipated expiration: 2026-12-15
Also published as: GB2545242A; AU2016366819B2; AU2016366819A1; GB2545242B; EP3387322B1; EP3387322A1; EP4056888A1; WO2017098487A1; GB201521756D0; CN209355087U

Abstract

A downlight assembly comprises a housing (11) made of a material having a melting point in excess of 900 ℃. The housing has a rear end wall (17, fig. 2b) closing the rear of the housing and at least one side wall. An LED module (12) is mounted in thermal contact with the rear end wall (17) of the housing. The downlight assembly does not have a separate conventional heat sink. The downlight assembly is fire resistant and includes a small vent hole. The electronic components are located in an annular space surrounding a lens or reflector of the downlight assembly.

Description

Down-spot lamp assembly

Divisional application statement

The application is a divisional application of a Chinese utility model patent application with the invention name of 'improved lower spotlight' and the application number of 201690001556.5, which is filed on 8, month and 10 days in 2018.

Technical Field

The utility model relates to a shot-light lamps and lanterns down, it is particularly useful for but not restricted to shot-light lamps and lanterns under the fire prevention.

Background

It is well known that it is of paramount importance in the lighting industry to prevent overheating of LED solid state lighting elements. Since most of the electric power consumed by the LED becomes heat rather than light, the life expectancy and light efficiency of the LED unit are greatly reduced if the heat is not effectively removed. Thus, efficient thermal management of high power LEDs is considered a key area of research and development, and all such LED downlights currently on the market, especially fire downlights (in which the LED solid state lighting elements are housed in a fire resistant housing), comprise some type of separate heat sink.

There have been many approaches to removing heat from LED solid state lighting units, such as passive and active heat sinks, heat pipes, and vapor chambers. Passive heat sinks have proven to be both economical and efficient in such applications (particularly in downlight designs), and it is also considered common knowledge that finned heat sinks are a fundamental requirement of any LED downlight. Among the common metals, aluminum is most often used as a heat sink material because it is relatively inexpensive, can be stamped or cast, and has a relatively high thermal conductivity k, which is approximately 200W/(m.k) (watts per meter kelvin), depending on the purity of the aluminum. Copper (k 400) and silver (k 429) are better thermal conductors than aluminum, but are more expensive and are not commonly used in heat sinks for fire resistant downlights. In contrast, mild steel, which is commonly used to make fire resistant housings or downlight cans, is a relatively poor conductor of heat, and has a k value of approximately 43 to 53, depending on the percentage of carbon content in the steel. Due to this low k value, heat sinks used in downlight fixtures are never made of mild steel.

In summary, as a conclusion of the above observations, it is currently considered common knowledge in the lighting industry: in order to obtain a good working life, the high power LED solid state lighting element must be in good thermal contact with the heat sink, and the heat sink is made of a material with good thermal conductivity (that is, with a thermal conductivity k higher than about 100W/(m.k)), and is preferably a finned aluminum heat sink. These heat sinks are referred to in the art as conventional heat sinks. Since a separate heat sink must be provided, the cost of the downlight is affected — money is consumed, precious natural resources are consumed, and the cost and time for assembly in the manufacturing process are increased. The total depth of the downlight is affected because the heat sink is inevitably located on the rear end face or wall of the downlight tank. This is an important factor, especially when there is limited space in the ceiling above the downlight, or behind the panel on which the downlight is mounted.

It is an object of the present invention to overcome or alleviate some or all of the problems outlined above.

SUMMERY OF THE UTILITY MODEL

According to the utility model discloses a first aspect provides a shot-light subassembly down. For example, the downlight assembly includes: a fire-resistant enclosure made of a material having a melting point in excess of 900 ℃, the fire-resistant enclosure comprising a substantially tubular body having a front side, a rear side, at least one side wall, and a rear end wall closing the rear of the fire-resistant enclosure; a solid state lighting element mounted in thermal contact with the rear end wall of the housing. Wherein the downlight assembly does not have a separate conventional heat sink. This is contrary to the general idea and understanding of the lighting industry, where there is no need for a separate conventional heat sink inside or outside the housing, and a fire-proof housing, for example made of mild steel, is able to dissipate the heat generated by the solid state lighting elements by transfer, convection and radiation. This results in significant savings in material and manufacturing costs.

Since the housing comprises a substantially tubular body having a front side, a rear side and at least one side wall. The housing can thus be formed as a stamping, for example from sheet material. The only hole required in the rear wall of the stamping is for allowing electrical cables to enter the solid state lighting elements and any associated control means. However, it will be appreciated that other vents may be provided in the rear end wall or side walls of the housing to aid in heat dissipation. If these holes are small, the fire rating of the assembly in a fire test is not compromised.

Preferably, the housing further comprises a flange extending outwardly at or towards the front side of the tubular body, the flange enabling the downlight to be fixed in a dividing surface (e.g. a ceiling).

In a particularly preferred embodiment, the solid state lighting element comprises a plurality of LEDs. By using a plurality of small LEDs instead of one large LED light engine, the heat it generates is spread over a larger surface area of the rear wall of the housing, thereby improving the life expectancy and the light efficiency of the LED unit.

Preferably, the plurality of LEDs are mounted on a printed circuit board, which is preferably a metal-Made Printed Circuit Board (MPCB), more preferably a metal PCB comprising aluminum. A PCB made of aluminum or other metal with a high heat transfer coefficient more efficiently transfers heat from the LEDs into the housing.

Preferably, the printed circuit board is directly attached to an inner surface of the rear end wall of the fire-resistant housing.

Preferably, a thermally conductive interface is provided between the PCB and the rear end wall of the housing. Suitable thermally conductive interfaces are, by way of example, thermally conductive grease, thermally conductive pads, graphite foil or thermally conductive acrylic films.

Preferably, the downlight assembly further comprises a reflector adapted to direct light from the solid state lighting element out of the front of the housing. The assembly may also include one or more lenses adapted to focus light produced by the LEDs into a desired beam angle.

Preferably, the assembly further comprises a lens adapted to focus light emitted by the solid state lighting element. In a particularly preferred embodiment, the additional electronic components are accommodated in an annular space which surrounds the lens or the reflector. The additional electronic components typically include one or more components selected from the group of components including a power supply component, a dimmer control component, a control IC component, and other electronic components.

Preferably, the additional electronic components are located substantially in the bottom cover. And preferably the additional electronic components are substantially covered by the top cover.

Preferably, the housing is constructed of steel, more preferably mild steel, and may advantageously be stamped from mild steel sheet material to maintain a reduction in manufacturing costs.

Drawings

The invention will now be described by way of example only with reference to the accompanying drawings, in which:

fig. 1 shows an exploded view of a downlight assembly according to an embodiment of the invention;

fig. 2A to 2F show various views of an assembled downlight according to the present invention;

fig. 3 to 7 show various views including cross-sectional views of an embodiment of the invention in which the control circuitry and components required to power and control the LEDs are contained inside the housing and in an annular space surrounding the lens;

FIG. 8 shows an exploded view of the components of another embodiment, wherein the control circuitry and components needed to power and control the LEDs are contained inside the housing;

fig. 9 and 10 show cross-sectional views of a housing containing a solid state lighting element that requires a remote drive (not shown) mounted in a ceiling;

fig. 11 and 12 show cross-sectional views of a housing including a built-in driver, the housing containing solid state lighting elements and being mounted in a ceiling;

fig. 13 illustrates how heat from the LED is transferred first to the PCB and then to the housing and thus into the air and environment surrounding the rear of the housing.

Detailed Description

In the context herein, the term "LED lighting module" refers to an operating LED light engine and its associated control circuitry, such as a power supply, a dimmer, and/or a control IC or electronics. The term "LED module" refers to one or more LED light engines mounted on a suitable PCB, with or without any associated control circuitry.

Referring to fig. 1, an exploded view of the components for a fire protection downlight assembly 10 is shown, the fire protection downlight assembly 10 having no additional or separate conventional heat sink in addition to the metal housing and not relying on intumescent materials to achieve a desired level of fire protection. The assembly includes: a fire-resistant housing 11, an LED module 12, a reflector 13, a diffuser 14 and a seal 15 to hold the diffuser in place. The housing is in effect a closed shallow can with a flange 16 extending outwardly around the front of the can. As shown in fig. 2B, the rear of the can body is closed by a rear wall 17. The assembly comprises spring loaded

arms

18, 19 supported by brackets 20, 21, the brackets 20, 21 being attached to the canister by rivets 22. These spring loaded arms press against the hidden side of the surface to which the downlight is mounted and hold the flange 16 firmly against the visible side of the surface. A clip 23 is attached to the outside of the rear wall of the housing, with an aperture (not shown) in the rear wall of the can through which to allow the cable to enter the LED module and any associated control devices. The one small cable entry hole does not affect the fire rating of the tank.

The LED module is attached directly to the inside face of the rear end wall of the can such that light from the LED is directed out of the open front face of the can or housing.

In case the housing is fire resistant, the housing is preferably made of a metal having a melting point above 900 ℃, more preferably above 1000 ℃. Steel is a suitable material and mild steel is particularly suitable due to its melting point exceeding 1400 ℃, which can be easily and cheaply pressed into the desired shape.

Fire standards for fire-resistant ceilings in the uk are set forth in BS EN1365-2: 2014. It is required that the fire-resistant member must be able to withstand a given temperature for a given period of time. The given temperature is around 1000 c, so any metal that can withstand that level of temperature can be used for the manufacture of the fire resistant enclosure. It will be appreciated that other countries may be given different temperatures in their fire protection standards. Importantly, although the housing is shown in this example as being stamped from a single piece of metal, the housing may be formed from two or more parts that are welded or otherwise securely fastened together.

The use of mild steel in the housing construction also works well even though the downlight assembly does not need to be fire resistant. However, if the downlight assembly does not require fire protection, it will be appreciated that a wider variety of other materials may be used to make the housing, if those materials have a relatively high thermal conductivity or if vents are provided in the housing. For example, various plastic materials such as polyamide or lower melting metals such as aluminum may be used for this purpose.

The LED module 12 includes a plurality of individual LED chips mounted on an aluminum PCB. The exact number of LED chips is not important to the invention and can be determined by the relevant expert depending on the power rating and the lumen output required. Arranging multiple LED chips is advantageous over arranging a single large LED chip because the heat generated is spread over a significantly larger surface area of the PCB and thus enters a larger area of the housing. In the example shown in fig. 1, approximately 24 individual LED chips are distributed over substantially the entire area of the PCB. A reflector plate 13 in the form of a polished truncated conical reflector is used to direct the light from the LED out of the front of the housing. The LEDs are protected by the diffuser 14 and the downlight assembly is secured in a surface such as a ceiling by means of the flange 16 and the spring loaded

arms

18, 19, the spring loaded

arms

18, 19 acting in a conventional manner against a concealed surface of the ceiling.

The LED PCB and thus the LED module 12 must be in good thermal contact with the inside of the rear end wall 17 of the housing 11. This good thermal contact may be enhanced by thermally conductive interface materials such as thermally conductive grease, thermally conductive pads or groups of pads, graphite foil, thermally conductive acrylic adhesive film, thermally conductive nanocomposites, or polymers. It will be appreciated that any suitable thermally conductive material may be used for this purpose. The inside face of the rear end wall 17 of the housing 11 is substantially planar to facilitate heat transfer over the entire surface area of the back of the LED PCB.

In the embodiments described above, the necessary power supply, dimmer and control IC are located in a remote driver unit (not shown). Including the other embodiments shown in fig. 3-8 in which the power supply, dimmer and/or control IC or electronics are located within the housing. In the example shown in fig. 3 to 7, 9 LEDs in a 3 x 3 array are located on a PCB provided on the rear wall 37 of the housing 31, and the LEDs may be in good thermal contact with the rear wall 37 if desired. Or these components may be thermally isolated from the housing, if desired. The power supply, dimmer, other control IC and other electronic components are located in a separate annular space surrounding the LED PCB and outside the lens 33. In one embodiment, these other components are preferably mounted on one or more PCBs that are separate or remote from the LED PCB. In this case, a solid (solid) substantially truncated conical lens 33 of conventional form directs the light from the LED out of the front of the housing by total internal reflection. This arrangement forms an annular cavity 44, and these additional components can be accommodated in the annular cavity 44. When the reflection plate 13 shown in fig. 1 is used, a similar ring cavity is formed.

These additional components may be thermally and electrically insulated from the housing, either by using a thermally insulating material, or by an air gap, or by using both a thermally insulating material and an air gap, in order not to add directly to the thermal load that must be dissipated by the housing.

Fig. 8 shows in exploded form a component comprising a downlight assembly of the type shown in fig. 3 to 7. The shell, which is stamped from steel, includes a forward flange 46. The LED module 42 on the PCB is fixed to the inside of the rear wall of the case 41 with a thermally conductive paste between the two surfaces. Disposed around the LED PCBs is a bottom cover 54 for the power, controller and driver components (which can be seen on their respective PCBs, 55 in fig. 8). The top cover 56 fits over the drive components and preferably a lens (not shown) occupies the interior space of the top cover. The assembly is completed by a diffuser 44 and a seal 45. The downlight assembly that contains the control circuitry and components needed to power and control the LEDs inside the housing is a downlight assembly with a built-in driver. A cross-sectional view of a downlight assembly of this type mounted in a ceiling is shown in fig. 11, and only the housing and LED module are shown in fig. 12. Corresponding views of a downlight assembly with a remote driver (not shown) are shown in fig. 9 and 10. For the downlight assemblies shown in fig. 9 and 10, to achieve the fire protection function, the fittings are steel which is resistant to high temperatures above 1000D. During a fire, the fittings do not fall off, remaining on the ceiling.

It will be appreciated that the arrangement described above by which the control member is located in a substantially annular space surrounding either the lens or the reflector or both the lens and the reflector, or the annular space behind either the lens or the reflector or both the lens and the reflector, is not only applicable to the embodiments described above and previously described, but also to other downlight assemblies. That is, most lenses and reflectors are substantially frustoconical in shape, which tends to leave a substantially annular space around the base of the lens or reflector, which space may be advantageous for accommodating various electrical and electronic components.

It will also be appreciated from the foregoing that a downlight assembly according to the present invention does not have any external housing, and there is no external housing surrounding or associated with the housing. Thus, when the housing is properly mounted behind some dividing surface (e.g. a ceiling), the housing is located in free space.

Fig. 13 illustrates a method of dissipating heat from an LED module from a housing. To LED SMT @ MCPCB, MCPCB is close to the steel tank body. Heat can be transferred to the steel body and then quickly drawn into the air to dissipate the heat. As will be understood from the above description, the heat generated by the LED module in use is transferred from the aluminum PCB to the

housing

11, 31, 41, 61 and dissipated by convection and radiation to the surrounding space and the environment surrounding the outside of the housing, i.e., the heat of the LEDs is transferred to the aluminum PCB and the steel and then can rapidly enter the air. Uniquely, this is achieved without the need for a separate conventional finned heat sink attached to or associated with the housing. Since some of the heat generated by the LED module is dissipated from the housing by radiation, it is advantageous to process the outer surface of the housing in a dark color, preferably black, more preferably a matte black. Black painting of steel housings with paint or black oxide is very easy and cost effective. However, it is expected that most of the heat lost from the housing is lost by convection rather than by radiation.

Claims

1. A downlight assembly, comprising:

a fire-resistant enclosure made of a material having a melting point in excess of 900 ℃, the fire-resistant enclosure comprising a substantially tubular body having a front side, a rear side, at least one side wall, and a rear end wall closing the rear of the fire-resistant enclosure;

a solid state lighting element mounted in thermal contact with the rear end wall of the housing;

characterized in that the downlight assembly does not have a separate heat sink.

2. The downlight assembly of claim 1, wherein the fire resistant housing further comprises a flange extending outwardly at or towards the front side of the tubular body.

3. The downlight assembly of claim 1 or 2, wherein the solid state lighting element comprises a plurality of LEDs.

4. The downlight assembly of claim 3, wherein the plurality of LEDs are mounted on a printed circuit board.

5. The downlight assembly of claim 4, wherein the printed circuit board is a metal-made printed circuit board.

6. The downlight assembly of claim 4 or 5, wherein the printed circuit board is directly attached to an inner surface of the rear end wall of the fire resistant housing.

7. The downlight assembly of claim 4 or claim 5 wherein a thermally conductive interface is provided between the printed circuit board and the rear end wall of the housing.

8. The downlight assembly of claim 1 further comprising a reflector adapted to direct light from the solid state lighting element out of the front of the housing.

9. The downlight assembly of claim 1, further comprising a lens adapted to focus light emitted by the solid state lighting element.

10. A downlight assembly according to claim 8 or 9 wherein the additional electronic components are housed in an annular space which surrounds the lens or reflector.

11. The downlight assembly of claim 10, wherein the additional electronic components comprise one or more of: power supply unit, dimmer control unit, and control IC unit.

12. The downlight assembly of claim 10, wherein the additional electronic components are substantially located in the bottom cover.

13. The downlight assembly of claim 10 wherein the additional electronic components are substantially covered by a top cover.

14. The downlight assembly of claim 1, wherein the fire resistant housing comprises steel.

15. The downlight assembly of claim 14, wherein the fire resistant housing comprises mild steel.

16. The downlight assembly of claim 1, wherein the heat sink comprises a finned heat sink.