GB2598401A

GB2598401A - Lighting fixture with low profile light guide

Info

Publication number: GB2598401A
Application number: GB2013730.3A
Authority: GB
Inventors: Ward Robert; Weston Thomas
Original assignee: Lumi Plugin Ltd
Current assignee: Lumi Plugin Ltd
Priority date: 2020-09-01
Filing date: 2020-09-01
Publication date: 2022-03-02
Also published as: GB2614187A; WO2022049060A1; GB202304633D0; GB202013730D0

Abstract

A lighting apparatus comprises a main housing with a first attachment means for securing the apparatus to a mounting surface; and a detachable outer portion 2 configured to form a front surface of the apparatus and having a PCB 16 and LED illumination means 4 fixedly coupled to the PCB 16. A light guide 6 is provided.

Description

Lighting Fixture With Low Profile Light Guide The present invention relates to a lighting fixture with a low profile light guide.

In the field of lighting systems, and particularly where lights are required to be fitted to the ceilings of indoor spaces, there is a desire to achieve effective illumination of the space whilst providing a fitting which does not dominate visually, but which is easy to replace and/or maintain. Lights which are recessed into the ceiling or walls of a room so that they are substantially flush with the ceiling or walls are now common. These have typically comprised one or more conventional bulbs in the centre of a rim portion which hides a hole in the ceiling in which the recessed light sits. More recently, this type of recessed ceiling or wall light has been designed to use LED bulbs, which are more environmentally friendly as well as being more efficient than traditional lightbulbs.

This type of light is attractive. However, changing the bulb or bulbs when these fail is notoriously difficult and the placement of the bulbs or other illumination means within the light, which does not have a shade in the same way as hanging lights generally will, can result in a patchy appearance or non-uniform illumination because the bulbs themselves are visible through the front of the device. In the case of LED lights, it is also difficult if not impossible to replace the bulbs or LED chips without needing to replace the entire unit. This, of course, means pulling the unit out of the ceiling in the case of recessed lights which requires effort or professional input and is costly.

There are also other issues with recessed lights, such as overheating, water damage, adaptability, and appearance. When a recessed light overheats, not only would it malfunction, it would also cause damage to the ceiling or wall in which it is installed. Recessed lights that are installed in areas prone to water leakage are exposed to the risk of water damage. Some recessed lights that are multi-functional lights are hard to adapt and it is desirable to keep the appearance of a recessed light discrete.

According to an aspect of the present invention, there is provided a lighting apparatus comprising a main housing with a first attachment means for securing the apparatus to a mounting surface; and an outer portion configured to form a front surface of the apparatus and having a first PCB and illumination means fixedly coupled to the PCB.

In embodiments, the outer portion is a detachable portion and has a second attachment means for removably coupling the detachable portion to the main housing such that the detachable portion, the PCB, and the illumination means can be removed from the main housing and replaced as one piece.

In embodiments, the housing is made from a thermally conductive material and is arranged to be in thermal contact with the PCB when the apparatus is assembled.

Preferably, at points of contact between the housing and the PCB, the surface of the housing is contoured and the surface of the PCB is provided with complementary contour so as to increase the area over which the housing and the PCB are in contact.

In embodiments, the main housing comprises a light guide to reflect light emitted by the illumination means back towards the front of the housing. Preferably, the housing is made from a thermally conductive material and is arranged to be in thermal contact with the light guide when the apparatus is assembled. Preferably, at points of contact between the housing and the light guide, the surface of the housing is contoured and the surface of the light guide is provided with complementary contour so as to increase the area over which the housing and the light guide are in contact. In some embodiments, the light guide is arranged to reflect light at its interior and its exterior includes a plurality of contact points that abut the main housing when assembled to provide a tortuous path that provides water ingress protection for the PCB and the illumination means.

Preferably, the contact points are arranged such that abutment of the light guide against the housing forms at least one cavity space.

In embodiments, the light guide includes one or more grooves, recesses, or dents arranged to receive one or more correspondingly positioned protrusions on a functional module or cap when inserted into the apparatus so as to secure the functional module or cap to the apparatus.

In embodiments, the housing includes a flange portion arranged to enable the apparatus to be seated at an opening in the mounting surface, wherein the apparatus includes a seal material that extends over the flange portion such that when the apparatus is installed the seal material extends over a rim of the opening. Preferably, the seal material provides water ingress protection. Alternatively, the seal material is made from an intumescent material. In some embodiments, the outer portion is configured to have a recessed area to accommodate the flange portion and the seal material.

In embodiments, the outer portion includes a rigid front exterior support member.

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a lighting apparatus; Figure 2 is a cross sectional view of a lighting apparatus with a light guide and a blanking cap inserted; Figure 3 is a perspective view of the cross section of a detachable portion of a lighting apparatus together with a light guide of a lighting apparatus; Figure 4 is another cross sectional view of a lighting apparatus with a light guide and a blanking cap inserted; Figure 5 is another cross sectional view of a lighting apparatus with a light guide and a blanking cap inserted; Figure 6 is a perspective view of the cross section of a lighting apparatus with a light guide; Figure 7 is a cross sectional view of a lighting apparatus with a light guide and illustrates the lighting apparatus installed in a ceiling panel; Figure 8 is another perspective view of the cross section of a lighting apparatus with a light guide.

Figures 1 and 2 illustrates an example of a lighting apparatus 1. Figure 1 is a perspective view and Figure 2 is a cross sectional view showing the detail that will be described in below. The apparatus 1 is intended for use as a ceiling downlight but can also be installed in any surface including walls, outdoor mounting surfaces, or even tables or flooring if desired. The lighting apparatus 1 is shown in figure 1 as free standing and includes an outer portion 2, which may be a rim section or detachable portion 2 in some embodiments, on which lighting emitting means 4 such as LED lights are provided and to which these lights are fixedly coupled. Fixedly coupled refers to the fact that these parts are not easily removed or detached and are not intended to be removed. Because of the particulars of the design and the positioning of PCBs and LEDs within the device, the size and the thickness of the portion of the apparatus that is visible when the apparatus is installed are both small in comparison to previous models.

The diameter of the outer rim/front face of the detachable portion 2 may be between 50mm and 150mm, or more preferably between 90mm and 130mm, or more preferably between 100mm and 120mm, or more preferably around 8mm. The thickness of the rim as measured from the mounting surface and in a direction away from the mounting surface (which may be a ceiling or wall surface) when installed is preferably between 4mm and 7mm, or more preferably between 5mm and 6mm, or more preferably around 5.5mm. It will be appreciated that the outer portion 2 may be detachable or non-detachable and features described herein for embodiments in which the outer portion 2 is a detachable portion are equally applicable to embodiments in which the outer portion 2 is non-detachable, unless the embodiment specifically requires a detachable outer portion 2.

The edges of the detachable portion 2 may be chamfered as shown, so that the portion of the detachable portion 2 protruding above the mounting surface once installed is frustoconical. This provides a more attractive appearance and reduces the likelihood of catching. The detachable portion 2 may be smooth in order to provide a streamlined appearance or may include finger holds or other protruding portions to aid its removal from front of the main housing 3.

As shown in figure 2, the light emitting means 4 are in the form of the LED chips and face away from the front surface of the lighting apparatus 1 so that the light emitted by the LED chips 4 is reflected by a light guide 6 and then back through a transparent or semi-transparent ring element 8 (which may be a filter or lens) on the front surface of the detachable portion 2. This way, individual bulbs are not visible, at least at any acute angle, and an attractive and consistent appearance of the illuminated halo is achieved. In the embodiment shown, the front ring element is in the form of a front lens 8, which is coupled to the detachable portion 2 and may be formed of polycarbonate in its entirety but at least in part. In some embodiment, the front element may be a filter instead of a lens. The front element 8 may also have a brushed aluminium front surface. The brushed aluminium front surface may be bonded to the front lens 8 to provide a sleeker appearance. An attractive and workable choice for the specification of the brushed aluminium is AA5052-H32. In some embodiments, the detachable portion 2 is provided with a rigid support member 10 at its front exterior side to provide structural support. In some embodiments, the rigid support member 10 is an aluminium cover 10 at least on the parts which will be visible in use in order to improve structural strength of the detachable portion 2 and optionally improve the appearance of the front surface of the apparatus 1. The finished article is ingress protection (IF) compliant and the visible portion of the apparatus 1 once installed is thinner than for previous ceiling or wall lights of a similar type, which tend to be bulky. The front element 8 and the detachable portion 2 may be over moulded together to ensure IP68 suitability. After manufacture, these are not separable parts but form one integral piece. Any functional module (not shown) or blanking cap 9 as shown in figure 2 may also have a brushed aluminium surface bonded to the front surface thereof to provide consistency with the front side of the detachable portion 2.

The centre of the main housing 3 provides a cavity 12, which in the case of the lighting apparatus 1 shown in figure 2 is a cylindrical cavity within the main housing 3.

Replaceable functional modules (not shown) can be fitted to the apparatus 1 within this cavity 12. The functional module can provide additional functions such as a sprinkler, camera, smoke alarm, heat alarm, Air ventilation, carbon monoxide alarms, emergency lighting, or speaker, and will generally also be substantially cylindrical in shape so that they fit snuggly within the cavity 12. The functional module may be held in place using any suitable means such as magnetic attachments, bayonet fittings, or by a snap fit mechanism so that one module may be easily replaced by another if desired. The fitting will generally be snap-fit as shown in the figures, for example, which can support both heavier and lighter functional modules. The snap fit mechanism comprises a plurality of resilient protrusions 13 extending from the blanking cap 9 or functional module, which are positioned such that when inserted to the cavity 12, the protrusions 13 snap into a groove 14 presented towards the interior of the cavity 12 to hold the functional module or blanking cap 9 in place. As shown in figure 5, and more clearly in figure 6, the groove 14 is provided on the side of the light guide 6 that is presented to the cavity 12. In the embodiment depicted in figure 6, the groove 14 extends continuously around the whole inner circumference of the light guide 6. In some alternative embodiments, the groove 14 may be discontinuous. In some other alternative embodiments, the groove 14 may be replaced by recesses or dents that are placed at appropriate points on the inner circumference of the light guide to receive the protrusions of the functional module or blanking cap 9.

For heavier functional modules (which may be cameras, smoke alarm, heat alarm, Air ventilation, carbon monoxide alarms, emergency lighting, or speakers) a bayonet fitting can be provided in addition to, or instead of, magnetic attachment means and/or the snap-fit mechanism. Magnetic attachment means are generally used more for lighter modules and blanking caps. The cavity 12 in the main housing 3 may comprise both bayonet and magnetic fittings so that either means can be used to attach a functional module, in which case heavier functional modules may comprise the corresponding parts of the bayonet fittings and the lighter modules the corresponding parts of the magnetic fittings to allow each to be secured within the cavity.

A blanking cap 9 may alternatively be fitted within the cavity 12 if no functional module is used in order to avoid the cavity 12 being visible and to retain an attractive and consistent appearance. Blanking caps will generally be held in place using the same snap-fit mechanism, magnetic attachment means, or bayonet fittings as the functional modules but can be held in place using any means. Figure 2 shows a lighting apparatus with a blanking cap 9.

Referring to figure 2 a cross sectional view of the apparatus 1 is shown. The semicircular light pipe or light guide 6 is visible, and this will typically (although not necessarily) extend all of the way around the rim of the apparatus 1 and be coupled to the main housing 3 rather than to the detachable portion 2. This light guide 6 may be formed of a reflective polycarbonate which helps to achieve a "true halo" effect where no visible LEDs or hotspots are evident. The assembly comprises the detachable portion 2 which can be easily dismounted from the front of the apparatus 1 and which can equally as easily be replaced itself or replaced with a similar detachable portion. A part or surface of the detachable portion 2 forms a front surface of the lighting apparatus 1 once the apparatus 1 is installed. The front surface refers to a surface of the apparatus 1 which faces the room or which faces away from the mounting surface, and which is usually visible when the apparatus 1 is installed. Obviously, depending on where the apparatus 1 is mounted, this surface may face downwards Of mounted in a ceiling) or sideways (if mounted in a wall) but it will always be referred to as the front surface. The front surface may be substantially parallel to the mounting surface when the apparatus 1 is mounted and may include a chamfered portion which is slightly at an angle to the mounting surface. This front surface of the detachable portion 2 may be any shape and does not necessarily cover the whole of the front of the main housing 3. In a preferred embodiment, the front surface of the detachable portion 2 (and of the lighting apparatus 1) is ring shaped. When a functional module is installed within the apparatus 1, this may also extend further forwards than the front surface formed by the detachable portion 2. In most cases the front surface of the detachable portion 2 will be ring shaped or shaped as a rim so that a functional module can be pushed through a hole in the middle of the rim in order to be able to be installed when the detachable portion 2 is already removably coupled to the main housing 3. This means that the detachable portion 2 and the functional module can each be separately and easily removed from the main housing 3 for replacement. If a bayonet fixing is used to couple the rim to the main housing 3 then the user simply has to twist the rim section and then pull to remove, or push and then twist to replace. It is also conceivable that other methods could be used to fix the rim to the main housing 3, such as magnetic connectors or snap-fit connectors. Any type of fixing can be used as long as the rim is able to be repeatedly removed and replaced.

Referring to figure 3, the detachable portion 2 comprises the light emitting device or devices 4, which will typically be one or more LED chips, along with a first printed circuit board 16 (the LED PCB). Various connectors (not shown) on the main housing 3 and the detachable portion 2 provide an electronic connection to a power supply and additional circuitry contained within the main housing 3. Once a connection is made, the PCB 16 in the detachable portion 2, which is coupled to the LED chips 4, connects to the electronics in the housing 3 so that the LED chips 4 can be powered and controlled. Electronics in the main housing 3 controls a power control unit (PCU) mains power supply inverter and a dimmer module in one embodiment, with the PCB 16 on the detachable portion 2 serving as a carrier and connection to the LED chips 4 as well as providing a low voltage power track to feed the LED chips 4 in order to illuminate them. Once the detachable portion 2 is properly coupled to the main housing 3, the LED chips 4 can be switched on and off or dimmed as desired. In some embodiments, markings can be used on the main housing 3 and detachable portion 2 in order to indicate to the user the relative position of the two parts required for electrical connection to be made between the two and/or a direction of rotation required to properly connect the detachable portion 2. Markings such as these can be used with any type of fixing between the detachable portion 2 and main housing 3, but will be particularly useful where a magnetic fixing is used because there may be several different orientations in which the detachable portion 2 and main housing 3 can couple together without the requisite electrical connection being made.

In some embodiments, the front of the detachable portion 2 can be provided with front element, which may be a semi-transparent cover, through which light from the LEDs passes in use. The cover 8 is polycarbonate talc filled. This material adds a level of light dispersion to provide a more muted, consistent, appearance to the illuminated halo portion of the front surface. This further diffuses the light passing through the front of the apparatus 1 and allows the light to appear as a smooth ring or halo having a consistent and attractive appearance. The cover 8 may be a filter or may be a lens configured to bend or focus the light in some way to achieve the desired effect. Either of the cover 8 or the light from the LED chips 4 themselves may be coloured if desired in order to provide a coloured light ring.

Figure 4 shows the path of the light rays from the LED chips 4 as the light passes out of the apparatus 1. The beam angle of the rays leaving the apparatus after having been reflected by the light guide 6 and passed through the lens or filter 8 may be between 80 and 120 degrees, and more preferably between 90 and 110 degrees, and still more preferably between 90 and 106 degrees, or around 106 degrees. The light guide 6 may be carefully shaped to provide a desired beam shape/angle. For example, the light guide 6 may be shaped in order that the widest angle at which the rays exit the apparatus 1 will correspond to the widest angle at which water from a sprinkler will exit the apparatus 1 when a sprinkler module is inserted into the cavity 12 in the centre of the apparatus 1. This angle may be 106 degrees. The shape of the light guide 6 is illustrated in figures Sand 4. The light guide 6 is shaped such that it comprises a curve which is tangent to the LED viewing angle with a radius of between 5mm and 9mm, more preferably between 6mm and 8mm, more preferably between 6.5mm and 7.5mm and more preferably around 6.9mm. The highest point of the curve is located at a height of between 6mm and 8mm and preferably around 6.8mm above the light source and the curvature is offset from the centre by around 1.1mm. The light guide 6 cross sectional shape may include a curve having one part with a radius of curvature of between 5mm and 9mm, more preferably between 6mm and 8mm, more preferably between 6.5mm and 7.5mm and more preferably around 6.9mm as above and another part with a radius of curvature of between 3mm and 7mm, more preferably between 4mm and 6mm, more preferably between 4.5mm and 5.5mm, and more preferably 5mm. In a preferred embodiment, the radius of curvature of the first part of the curve will be around 6.9mm and the radius of curvature of the second part of the curve will be around 5mm. The point on the curve at which the transition between the areas with the two different radii of curvature may be at the highest point on the curve, or may be offset from this to one side where the transition between the areas of different radius of curvature is offset from the highest point on the curve towards the outer wall of the main housing 3 by between 0.7mm and 1.5mm, preferably around 1.1mm. The width of the front element 8, through which the light rays reflected from the light guide 6 pass, may be between 5mm and 15mm, more preferably between 8mm and 10mm, and most preferably around 9mm as shown.

The particular shape of the light guide 6 means that if the lighting apparatus 1 is mounted on the ceiling of a room then the circular light patch on the floor of the room will correspond to the area which will be doused with water during a fire. This aids a decision as to where to place the lights so that substantially the whole floor will be illuminated and the same area corresponding to substantially the whole floor will be sprayed with water once the sprinklers are activated. The light guide 6 can be shaped such that a circle, rather than a ring, of light on the floor of the room is present which provides for a better, more even, and more attractive lighting environment.

As illustrated in figure 4, light from the LED chips 4 is emitted such that it travels away from the front surface of the apparatus and rearward towards the light guide 6. The light guide 6, which may be substantially in the shape of a half pipe extending all of the way around the main housing 3, then reflects the light outwards through a ring shaped opening in the front surface of the housing 3. The ring shaped opening may be covered by a diffusive and/or semi-transparent material to further diffuse the light in order to provide a consistent illumination. This material may also (or instead) be a lens so that some refraction of the light may occur as it passes through. The lens or filter 8 may be formed from polycarbonate with talc. The properties of the lens 8 and the shape of the housing 3, and in particular of the light guide 6, can together be configured such that the diameter of the illuminated portion of a floor corresponds to the area of the floor which will be doused with water by a sprinkler if this is used as the central functional module. The circular area may be between 2 and 6 meters in diameter, or more preferably between 2.5 and 5.5 meters in diameter, or more preferably around 4 meters in diameter for a standard ceiling height of around 2.5 meters. A ring shaped halo of light (visible through the ring shaped front element) and a ring shaped light guide 6 are preferred but are not essential. The part of the front of the detachable portion 2 through which light passes in use is not necessarily in the shape of a halo/ring although this is preferred. The halo may only extend part of the way around the housing, for example, or may be broken up into several smaller illuminated parts depending on the configuration of the light guide 6 and the position of the front element 8, of which there may be several in some embodiments. A circular central portion may also be illuminated; however this would obviously mean that a cavity 12 would no longer be present for the provision of additional functional modules, and the ring shaped illumination portion or "halo" is the most aesthetically pleasing configuration.

The above-described shape and geometry of the light guide 6, together with the other herein described features of the housing 4, detachable portion 2, lens 8, and other parts of the apparatus 1 (in any suitable combination or permutation), minimizes the profile of the apparatus 1. This means that when the apparatus 1 installed, it is visually less obtrusive and more aesthetically pleasing.

Referring back to figure 3, the LED chips 4 sit on a PCB 16, which is connected to the back surface of the detachable portion 2. In some embodiments, the PCB 16 or PCBA is formed from glass fibre reinforced epoxy resin with a copper foil bonded to one or both sides of the PCB 16. The removable part comprises only the bevelled ring shaped portion, which may be formed of plastic in some embodiments, coupled to the semi-transparent element or lens 8 if present, the PCB 16 for the LED chips 4, electronic couplers such as conductive regions for coupling with pogo pin connectors (not shown) on the main housing 3 to connect the electronics in the detachable portion 2 to those in the main housing 3, mechanical couplers to removably attach the detachable portion 2 to the main housing 3, and the LED chips 4 themselves. No additional structure need be present (and the filter or lens 8 can in some embodiments be dispensed with although this will clearly have a negative effect on the appearance of the device). This section is lightweight, and relatively simple to manufacture. The mechanical means of attachment with the main housing 3 may be provided as a bayonet type mount with tabs and slots on the main housing 3 and the detachable portion 2 respectively. Tabs on the main housing 3 are aligned with slots on the detachable portion 2 and the two are pushed together and then turned so that tabs on both portions align to removably fix the detachable portion 2 in place. This means that the detachable portion 2 need only be pushed towards the main housing 3 and then turned to hold the detachable portion 2 in place. The attachment may, however, be provided by other means than a bayonet fixing, such as via a magnetic attachment or a screw thread.

The inclusion of a lightweight, removable, and reasonably small-sized rim to which LEDs 4 and LED PCBs 16 are coupled means that this part of the apparatus 1 can be separately replaced. Previously, if a LED chip 4 of the lighting assembly were to fail the entire assembly would require replacement. Because of the complexity of the installation process the replacement of an entire unit may require the services of a trained electrician. The above-described apparatus 1 does not need to be replaced each time an LED chip 4 fails. Instead, the detachable portion 2 only is dismounted from the main housing 3 using a simple twist and pull motion and is replaced with a new rim. This utility also means that the colour of the filter or lens, bulbs, or rim section itself can be changed easily if desired or to fit with a new colour scheme in a particular room.

A built-in driver may and in most cases will be included as part of the electronics in the main housing 3 to allow communication with a remote device via wireless connection (such as a WLAN connection). The lighting system can then be controlled from the remote device, which may be a mobile phone or tablet, to turn the lights on and off or to dim them if desired.

Referring still to figures 3 and 4, in embodiments of the apparatus 1, the light guide 6 is shaped and configured so as to provide water ingress protection to protect the PCB 16, the LED chips 4 and electronics on the PCB 16. In the embodiment depicted in figures 3 and 4, the detachable portion 2 comprises an outer ring portion 18 together with the front element 8, which is also ring shaped and is concentric within the outer ring portion 18.

When assembled, the two separate rings of the outer ring portion 18 and the front element 8 are interconnected to form one ring. The interconnected outer ring portion 18 and front element 8 has a front facing side, or a front surface as described above, through which light from the LED chips 4 (reflected off the light guide 6) passes when in use. A space, made up of suitable contours of the outer ring portion 18 and the front element 8, is provided on the back facing side (i.e. the side facing the opposite direction to the front facing side) in which the PCB 16 is nestled when assembled. The light guide 6, which is in the shape of a lower case "n" at its cross section, is positioned at the back facing side of the detachable portion 2 when the apparatus 1 is assembled to enclose the LED chips 4 such that the concaved interior side of the "n" shape of light guide 6 provides the reflective surface as described above. More generally, the cross section of the light guide 6 may be other suitable shape that has a concaved interior that enables light from the LED chips 4 to be reflected in the manner described above. In the embodiment depicted in figures 3 and 4, the top of the "n" shape of the light guide 6, at its exterior, provides two contact points 20 when viewed in the cross section that abuts the housing 3 that encases the light guide 6 when the apparatus 1 is assembled. The abutment between the light guide 6 and the housing 3 creates a tortuous path that provides water ingress protection that prevents water from seeping around the exterior of the light guide 6 and reaching exposed parts of the PCB 16 and other sensitive electronic parts of the apparatus 1. The abutment also creates a cavity space 22 in which any water that breaches one contact point 20 can gather instead of leaking further and potentially causing damage to electronic components of the apparatus 1. In the embodiment shown in figures 3 and 4, the light guide 6 has two contact points 20.

However, it will be appreciated that the light guide 6 may have fewer or more contact points 20, although multiple contact points 20 is preferred as such an arrangement provides the tortuous path described above. It will also be appreciated that the light guide 6 may have contact points 20 elsewhere on its exterior where it abuts the housing 3 or other components such as the detachable portion 2. For example, in the embodiment depicted in figures 3 and 4, one of the "legs" of the "n" shaped light guide 6 includes a contact point 24 that contacts the front element 8 when the apparatus 1 is assembled to form a pinch point that provides water ingress protection at that point. It will also be appreciated that the light guide 6 may have the same cross sectional shape along the whole of its circumference or along a substantial portion thereof, or varies circumferentially. It will also be appreciated that these features apply to a detachable portion 2 that is ring shaped or any other closed loop shape capable of providing the necessary opening for a functional module to pass through as described above.

Figure 4 also shows that in some embodiments, the housing 3 contacts the PCB 16 at contact point 26 when the apparatus 1 is assembled. In these embodiments, and when the housing 3 is made from a thermally conductive material such as stainless steel, the contact point 26 permits heat generated at the PCB 16 when the apparatus 1 is in operation to be conducted away, thereby aiding in the cooling of the apparatus 1 when it is in operation. In some variations of these embodiments, the housing 3 is in contact with the PCB 16 at multiple points to further assist in the cooling of the PCB 16. By assisting the cooling of the PCB 16, the product life of the apparatus 1 is extended. Similarly, the contact points 20 between the housing 3 and the light guide 6 assists in the cooling of the light guide 6, which may also heat up when the apparatus 1 is in operation. In some of these embodiments, the contact points 20 between the light guide 6 and the housing 3 and/or the contact point 26 between the PCB 16 and the housing 3 may be contoured to increase the contact area to enhance the conduction of heat. For example, at contact points 20 (and similarly at contact point 26), the light guide may be contoured with a ribbed surface and the housing 3 with a complimentary contour to increase the area over which the light guide 16 is in contact with the housing 3. In some other embodiments, a heat transfer material, such as a thermal putty, is alternatively or additionally provided to further enhance heat conduction.

Referring to figures 7 and 8, one of a number of embodiments in which the housing 3 has a flange portion 28 is shown. The flange portion 28 allows the apparatus 1 to sit at the rim of the opening into which the apparatus 1 is installed. In the embodiment shown in figure 7 and 8, the apparatus 1 is seated at an opening in a ceiling panel 5, although it will be appreciated that the apparatus 1 may be installed in an opening at some other location such as a wall or floor panel. When the detachable portion 2 is attached to the apparatus 1, the flange portion 28 is concealed by the detachable portion 2 to create an aesthetically pleasing appearance. In this embodiment, the apparatus 1 further includes a seal 30 around the flange portion 28, which contacts the rim of the opening of the ceiling panel 5 when the apparatus 1 is installed. The seal 30 extends over the flange portion 28 such that when the apparatus 1 is installed, the seal extends around the edge of the rim of the opening to ensure a good seal between the flange portion 28 and the ceiling panel 5. In some embodiments, the seal 30 is formed of a material that provides ingress protection to enable the apparatus 1 to achieve an IPX5 rating. In some alternative embodiments, the seal 30 is made from an intumescent material to enable the apparatus 1 to achieve fire protection rating. In some other embodiments, the detachable portion 2 is shaped in the cross section to have a recess 32 to accommodate the flange portion 28 and the seal 30 so as to maintain a low profile when it is attached to the apparatus 1. In these embodiments, the flange portion 28 is arranged such that with the seal 30 provided thereon, the apparatus 1 is still able to be installed through a 92mm diameter opening. Li

Embodiments of the present invention have been described with particular reference to the examples illustrated. However, it will be appreciated that variations and modifications may be made to the examples described within the scope of the present invention.

Claims

Claims 1. A lighting apparatus comprising: a main housing with a first attachment means for securing the apparatus to a mounting surface; and an outer portion configured to form a front surface of the apparatus and having a first PCB and illumination means fixedly coupled to the PCB.
2. A lighting apparatus according to claim 1, wherein the outer portion is a detachable portion and has a second attachment means for removably coupling the detachable portion to the main housing such that the detachable portion, the PCB, and the illumination means can be removed from the main housing and replaced as one piece.
3. A lighting apparatus according to claim 1 or 2, wherein the housing is made from a thermally conductive material and is arranged to be in thermal contact with the PCB when the apparatus is assembled.
4. A lighting apparatus according to claim 3, wherein at points of contact between the housing and the PCB, the surface of the housing is contoured and the surface of the PCB is provided with complementary contour so as to increase the area over which the housing and the PCB are in contact.
5. A lighting apparatus according any preceding claim, wherein the main housing comprises a light guide to reflect light emitted by the illumination means back towards the front of the housing
6. A lighting apparatus according to claim 5, wherein the housing is made from a thermally conductive material and is arranged to be in thermal contact with the light guide when the apparatus is assembled.
7. A lighting apparatus according to claim 6, wherein at points of contact between the housing and the light guide, the surface of the housing is contoured and the surface of the light guide is provided with complementary contour so as to increase the area over which the housing and the light guide are in contact.
8. A lighting apparatus according to any of claims 5 to 7, wherein the light guide is arranged to reflect light at its interior and its exterior includes a plurality of contact points that abut the main housing when the apparatus is assembled to provide a tortuous path that provides water ingress protection for the PCB and the illumination means.
9. A lighting apparatus according to claim 8, wherein the contact points are arranged such that abutment of the light guide against the housing forms at least one cavity space.
10. A lighting apparatus according to any of claims 5 to 9, wherein the light guide includes one or more grooves, recesses, or dents arranged to receive one or more correspondingly positioned protrusions on a functional module or cap when inserted into the apparatus so as to secure the functional module or cap to the apparatus.
11. A lighting apparatus according to any preceding claim, wherein the housing includes a flange portion arranged to enable the apparatus to be seated at an opening in the mounting surface, wherein the apparatus includes a seal material that extends over the flange portion such that when the apparatus is installed the seal extends over a rim of the opening.
12. A lighting apparatus according to claim 11, wherein the seal material provides water ingress protection.
13. A lighting apparatus according to claim 11, wherein the seal material is made from an intumescent material.
14. A lighting apparatus according to any one of claims 11 to 13, wherein the outer portion is configured to have a recessed area to accommodate the flange portion and the seal material.
15. A lighting apparatus according to any preceding claim, wherein the outer portion includes a rigid front exterior support member.