GB2585705A

GB2585705A - Lighting apparatus with detachable portion

Info

Publication number: GB2585705A
Application number: GB1910063.5A
Authority: GB
Inventors: Ward Bob; Weston Tom
Original assignee: SLEEP SAFE SYSTEMS Ltd
Current assignee: SLEEP SAFE SYSTEMS Ltd
Priority date: 2019-07-12
Filing date: 2019-07-12
Publication date: 2021-01-20
Also published as: GB201910063D0

Abstract

A lighting apparatus comprises a main housing 2 with a first attachment means for securing the apparatus to a mounting surface; and a detachable portion 4 forming a front surface of the apparatus and having a PCB and LEDs 6 fixedly coupled thereto and a second attachment means for removably coupling the detachable portion 4 to the main housing 2 such that the detachable portion, the PCB and the LEDs 6 can be removed from the main housing 2 and replaced as one piece. The lighting apparatus may also include a light guide 8 for reflecting light emitted by the LEDs towards the front surface of the housing to cover a circular area on the floor of a room when the apparatus is installed in the ceiling of the room. A fire sprinkler module may be coupled to the main housing such that the area of the floor of the room doused with water when the sprinkler is activated corresponds to the circular area.

Description

Lighting Apparatus with Detachable Portion The present invention relates to an improved lighting apparatus. In embodiments, the present invention relates to a lighting apparatus with a detachable portion. In embodiments, the present invention relates to a lighting apparatus with a removable illumination portion, a removable bulb unit, or a removable rim.

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. US-A-2018/0266635, for example, describes a recessed LED light including a central optoelectronic module which includes all of the electronics required to power the LED bulbs. The light also includes a separate rim module. The optoelectronic portion is pushed into a central opening in the rim module for installation. The rim includes fasteners which then securely fix the rim to the ceiling. Once this action has been completed it is extremely difficult to detach the rim module from the rest of the device, and thus it is also difficult to replace or remove the separate optoelectronic module.

According to a first 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 a detachable portion configured to form a front surface of the apparatus and having a first PCB and illumination means fixedly coupled thereto and 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. The detachable portion, PCB, and illumination means together (optionally with additional parts such as an integral lens or filter) can be referred to as a "halo bulb unit". The halo bulb unit is lightweight, is manufactured as one integral unit, and can be easily detached from a front surface of the housing and reattached thereto without having to move, reconfigure, or detach any other part of the lighting apparatus.

The fact that the halo bulb unit is lightweight, together with its location at the front of the apparatus, make it easy to access and remove even after the main housing has been installed in a wall or ceiling acting as the mounting surface. Particularly in the case of LED lighting systems, it has previously been necessary to replace entire units even in the case of failure of a single LED chip. This is inconvenient and costly because a replacement unit often requires a complex installation which cannot be completed by the user themselves In an embodiment, the second attachment means comprises a bayonet fitting. A bayonet fitting means that the detachable portion need only be pushed and then turned in order to provide the reversible coupling to the main housing. Because of the position of the tabs it is easy to determine whether or not the detachable portion is in its secured position, at which point electrical connectors on the detachable portion and main housing will line up and a connection will be made with the PCB on the detachable portion in order to power the illumination means.

In an embodiment, electrical connectors are provided on each of the main housing and the detachable portion. The connectors on the detachable portion are in contact with the connectors on the main housing to allow current to flow between the two when the detachable portion is coupled to the main housing. If spring loaded connectors are used these also provide a positive pressure to assist with maintaining the electrical connection. In an embodiment, the electrical connectors are pogo pin connectors (see figure 6C for a possible location of the connectors 28). It is possible via the use of pogo pins for the electrical connection to be made only when the detachable portion is in its fully secured position which may increase safety of the device. This selective connection is controlled by means of a contact position of the pogo pins on the LED PCBA. During the turning motion required to fix the detachable portion in place, the negative pogo pin is in constant contact with a contact track on the LED PCBA which extends a part of the way around the rim (the track will lie in the vicinity of the area indicated as numeral 46 in figure 7D). At a later point in the rotation, the positive pogo pin contacts a smaller conductive pad when the rotation is complete, the mechanical connection has been made, and the detachable portion is securely in place and removably coupled to the main housing. This ensures that the negative pogo pin always contacts before the positive pogo pin. Even when a snap-fit mechanical coupling is used, the detachable portion may need to be rotated until the connection with the positive pogo pin is made.

In an embodiment, the front surface formed by the detachable portion is ring-shaped. The detachable portion therefore forms a rim around the edge of and a hole directly above a central cavity in the main housing into which a functional module or blanking cap can be fitted without it being necessary to remove the detachable portion.

In an embodiment, the LED PCB and the illumination means are coupled to the rear surface of the detachable portion such that the light is emitted in a direction away from the front surface of the apparatus once installed. Because light does not travel directly from the illumination means towards the room in which the light is mounted the lights are not visible as separate hot spots.

In an embodiment, the illumination means are LED chips.

In an embodiment, the main housing comprises a light guide to reflect light emitted by the illumination means back towards the front of the housing. The reflective surface which reflects the light back out of the front of the device can also be shaped to direct light into the room in a particular way (to form a ring or a circular patch on the floor of the room, for example).

In an embodiment, the light guide is formed from a reflective polycarbonate. In embodiments, the light guide can be formed from a reflective ABS polymer.

In an embodiment, the light guide directs light through a lens or filter on the detachable portion.

In an embodiment, the lens or filter is ring-shaped. This ring-shaped filter may sit inside the ring-shaped front surface of the detachable portion. The two may be manufactured as one integral piece.

In an embodiment, the light guide is configured to reflect light to cover a circular area on the floor of a room when the apparatus is installed on the ceiling of the room.

This may provide a better lighting to the environment and may improve visibility in the room. In an embodiment, the circular area corresponds to a circular area of the floor doused with water when a fire sprinkler is installed within a cavity in the central housing and is activated. Ensuring that areas of the floor which will be illuminated and doused with water in the event that a sprinkler is activated correspond makes planning the layout of a room easier.

In an embodiment, the lighting apparatus comprises a PCB coupled to the main housing. These parts of the apparatus may need to connect up to the mains and may be bulky and heavy. Removal and replacement of the detachable portion does not involve any rearrangement of the heavier parts of the device and thus can be a simplified process carried out by a user without the involvement of a qualified electrician. The PCU PCBA in the main housing provides isolation from the mains voltage at 240V. The LED PCBA uses a lower voltage of 20V meaning that the detachable portion is safe for removal without a qualified electrician being present.

According to a second aspect of the present invention there is provided a detachable portion for a lighting apparatus, the detachable portion comprising: attachment means for removably coupling the detachable portion to the front of a main housing to form a front surface of the lighting apparatus, wherein at least one illumination means and at least one PCB are fixedly coupled to the detachable portion such that the illumination means, PCB, and detachable portion can be removed from the main housing as one piece.

According to a third 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; a light guide coupled to the main housing and configured to reflect light emitted by illumination means coupled to the apparatus towards the front surface of the housing to cover a circular area on the floor of a room when the apparatus is installed in the ceiling of the room; a fire sprinkler module configured to be coupled to the main housing such that the area of the floor of the room doused with water when the sprinkler is activated corresponds to the circular area.

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings, in which: Figure 1A shows a lighting apparatus mounted to a mounting surface, Figure 1B shows a lighting apparatus including a central functional module; Figure 2A shows a front view of a mounted lighting apparatus; Figure 2B shows a side view of a mounted lighting apparatus; Figure 3 shows a cross section of a lighting apparatus; Figure 4A shows a half cross section of a lighting apparatus with the path of light rays indicated; Figure 4B illustrates the beam angle in one configuration of a lighting apparatus; Figure 5 shows a cross section of a light guide with dimensions indicated; Figure 6 shows a room layout illustrating portions of the floor of the room which will be doused with water when a sprinkler incorporated into a lighting apparatus is activated; Figure 7A shows a front perspective view of a lighting apparatus including the detachable portion, in this case a removable rim, and main housing sections; Figure 76 shows a rear perspective view of a lighting apparatus including the detachable portion and main housing sections; Figure 7C shows the underside of the main housing, including the position of the pogo pin connectors; Figure 7D shows the assembled main housing and detachable portion with pogo pin connectors providing an electrical coupling between the two; Figure 8 shows a rear view of a lighting apparatus; Figure 9 illustrates an optional means for connecting the lighting apparatus to a mains power supply; Figure 10 shows a front perspective view of a lighting apparatus and blanking cap; Figure 11 shows a half cross section of a lighting apparatus including a seal or seals for fire prevention; Figure 12A is a plot showing contours of equal luminosity at different distances from a point directly below the centre of the lighting apparatus as a proportion of the luminosity at that point.

Figure 126 is a luminous intensity distribution diagram relating beam angle to luminous intensity.

Figures 1A and 1B illustrate an example of an LED lighting apparatus 2, which will be described in detail below. The apparatus 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 light is shown in figures 'IA and 1B installed in a wall or ceiling and includes a rim section or detachable portion 4 on which 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 may be between 50mm and 150mm, or more preferably between 90mm and 130mm, or more preferably between 100mm and 120mm, or more preferably around 110mm as shown in figure 2A. 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 between 4mm and 7mm, or more preferably between 5mm and 6mm, or more preferably around 5.5mm as shown in figure 2B.

The edges of the detachable portion may be chamfered as shown, so that the portion of the detachable portion protruding above the mounting surface once installed is frustoconical. This provides a more attractive appearance and reduces the likelihood of catching. The detachable portion 4 may be smooth in order to provide a streamlined appearance as shown in the figures or may include finger holds or other protruding portions to aid its removal from front of the main housing.

The LED chips 6 face away from the front surface of the light so that the light emitted by the chips is reflected by a light guide 8 and then back through a transparent or semi-transparent ring of material 10 (which may be a filter or lens) on the front surface of the detachable portion 4. 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. The front lens (which may be formed in its entirety but at least in part from polycarbonate-talc) is coupled to the detachable portion, which may be formed of polycarbonate and may have a brushed aluminium front surface bonded thereto to provide a sleeker appearance. The detachable portion 4 may also have a brushed aluminium cover or coating at least on the parts which will be visible in use in order to improve the appearance of the front surface of the apparatus. An attractive and workable choice for the specification of the brushed aluminium is AA5052-H32. The finished article is IA compliant and the visible portion of the apparatus once installed is thinner than for previous ceiling or wall lights of a similar type, which tend to be bulky. The lens/filter and the detachable portion may be over moulded together to ensure IP68 suitability. After manufacture these are not separable parts but form one integral piece. Any functional module or blanking cap may also have a brushed aluminium surface bonded to the front surface thereof to provide consistency with the front of the detachable portion.

The centre of the main housing provides a cavity 12, which in the case of the light shown in figures 1A and 1B is a cylindrical cavity within the main housing 14, and behind the hole 16 in the centre of the ring shaped detachable portion 4. Replaceable modules 18 can be fitted to the apparatus within this cavity. These will generally also be substantially cylindrical in shape so that they fit snuggly within the cavity 12 and may be held in place using magnetic attachments, bayonet fittings, by means of a snap fit mechanism, or by any other means so that one module may be easily replaced by another if desired. The fitting will generally be snap-fit as shown in figure 10, for example, which can support both heavier and lighter functional modules. The snap fit mechanism comprises a plurality of bendable tabs 11 on a rim extending from the blanking cap or functional module which can snap into a groove 13 within the wall of the cavity to hold the functional module in place. If a snap-fit connection is used, the functional module may need to be removed by application of pressure from behind, which may require the unit to be pulled out of the ceiling hole slightly. This would not require full removal of the unit. A mechanism for causing pressure to be applied from the back of the functional module without it being necessary to pull the unit away from the mounting surface could be devised, such as a string or similar bendable device for passing over the back of the unit which can then be pulled. For heavier functional modules (which may be cameras 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 14 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.

The central cylindrical modules 18 can provide additional functions such as a sprinkler, camera, or speaker. A blanking cap 22 may alternatively be fitted within the cavity if no functional module is used in order to avoid the cavity 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 1A shows a lighting apparatus with a blanking cap fitted and figure 1B with a functional module installed (a speaker in this case).

Figure 3 illustrates a slice through the apparatus. The semi-circular light pipe or light guide 8 is visible, and this will typically (although not necessarily) extend all of the way around the rim of the apparatus 2 and be coupled to the main housing rather than to the detachable portion. This light guide 8 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 a removable rim section or detachable portion 4 which can be easily dismounted from the front of the apparatus and which can equally as easily be replaced itself or replaced with a similar detachable portion. A part or surface of the detachable portion 4 forms a front surface 24 of the lighting apparatus 2 once the apparatus is installed, for example in a ceiling or wall. The front surface refers to a surface of the apparatus which faces the room or which faces away from the mounting surface, and which is usually visible when the apparatus is installed. Obviously, depending on where the apparatus is mounted this surface may face downwards (if mounted in a ceiling) or sideways Of 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 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 may be any shape and does not necessarily cover the whole of the front of the main housing. In a preferred embodiment, the front surface 24 of the detachable portion (and of the lighting apparatus) is ring shaped as shown in figure 7A.

When a functional module is installed within the apparatus, this may also extend further forwards than the front surface formed by the detachable portion (as in the case of the speaker shown in figure 1B). In most cases the front surface 24 of the detachable portion will be ring shaped or shaped as a rim so that a functional module 18 can be pushed through a hole in the middle of the rim in order to be able to be installed when the detachable portion is already removably coupled to the main housing 14. This means that the detachable portion and the functional module can each be separately and easily removed from the main housing for replacement.

If a bayonet fixing is used to couple the rim to the main housing 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, 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. The rim section comprises the light emitting device or devices 6, which will typically be one or more LED chips, along with a first printed circuit board 26 (the LED PCB). Connectors 28 on the main housing 14 and the detachable portion 4 provide an electronic connection to the power supply and additional circuitry (including a PSU PCBA 30) contained within the main housing. Once a connection is made, the PCB 26 in the detachable portion, which is coupled to the LED chips, connects to the electronics including PCBA 30 in the main housing so that the light can be powered and controlled. The PCBA 30 in the main housing controls a power control unit (PCU) mains power supply inverter and a dimmer module in one embodiment, with the PCB 26 on the detachable portion serving as a carrier and connection to the LED chips as well as providing a low voltage power track to feed the LED chips in order to illuminate them. Once the detachable portion is properly coupled to the main housing the LED chips can be switched on and off or dimmed as desired. In some embodiments, markings can be used on the main housing and detachable portion 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. Markings such as these can be used with any type of fixing between the rim and main housing, but will be particularly useful where a magnetic fixing is used because there may be several different orientations in which the detachable portion and main housing can couple together without the requisite electrical connection being made.

The front of the detachable portion can be provided with a semi-transparent covering 10 through which light from the LEDs passes in use. The covering 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 and allows the light to appear as a smooth ring or halo having a consistent and attractive appearance. The covering 10 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 or the light from the LED chips themselves may be coloured if desired in order to provide a coloured light ring.

Initial installation of the apparatus is achieved by inserting the main housing through a hole in a ceiling or wall. In order to fix the main housing in place it is coupled to two arms 32 which are spring loaded in order to push against the inner wall of the mounting surface (facing away from the room) to force the main housing up into the hole.

This is prevented from passing all the way through by a rim around the front surface of the housing.

The PSU in the main housing 14 connects to the mains and may convert mains AC to a low voltage DC current in order to provide power to the apparatus. The PSU may comprise the main housing PCBA as well as all of the components which may be coupled to this PCBA (these components are visible in figure 9). The apparatus may also include a chargeable or non-chargeable battery which can provide back-up power in the event of failure of the mains. This may be important in an emergency situation. Batteries may normally charge from the mains. Generally, the PCU will include a 2-4 hour (preferably 3 hour) power pack which is mains powered to trickle charge meaning that if the mains power supply should fail, for example in the event of a fire in the building, the apparatus would be capable of providing illumination without mains power for enough time to facilitate safe exit from the building. The power pack is not shown in the figures and may be provided as a separate product configured to connect to the lighting apparatus.

Figure 4A shows the path of the light rays from the LED bulbs as the light passes out of the apparatus. The beam angle of the rays leaving the apparatus after having been reflected by the light pipe and passed through the lens or filter 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 as shown in figure 4B. The light pipe 8 may be carefully shaped to provide a desired beam shape/angle. For example, the light pipe may be shaped in order that the widest angle at which the rays exit the apparatus will correspond to the widest angle at which water from a sprinkler will exit the apparatus when a sprinkler module is inserted into the cavity in the centre of the apparatus. This angle may be 106 degrees. The shape of the light pipe is illustrated in figure 5 On which measurements are shown in units of mm). The light guide 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 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 as shown in the figure. 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 as shown in figure 5 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 by between 0.7mm and 1.5mm, preferably around 1.1mm. The width of the filter/lens material, through which the light rays reflected from the light guide pass, may be between 5mm and 15mm, more preferably between 8mm and lOmm, and most preferably around 9mm as shown.

The particular shape of the light guide means that if the lighting apparatus 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. Figure 6 shows an example layout for a room. The dotted circles represent the area of the floor which are to be doused with water when the sprinkler functional module is inserted in the centre of the lighting apparatus and the sprinkler functionality is activated. In the above embodiment these will also represent the largest extent of the area of light on the floor of the room when the light is switched on. The light pipes 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 4A, light from the LEDs is emitted such that it travels away from the front surface of the apparatus and rearward towards the light pipe or light guide 8. The light pipe, which may be substantially in the shape of a half pipe extending all of the way around the main housing, then reflects the light outwards through a ring shaped opening in the front surface of the housing. 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 may 10 be formed from polycarbonate with talc. The properties of the lens and the shape of the housing, and in particular of the light guide, 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 filter/lens) and a ring shaped light guide are preferred but are not essential. The part of the front of the detachable portion 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 and the position of the filter/lens, 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 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.

As shown in figure 11, the LED chips 6 sit on a PCB 26 which is connected to the back surface of the detachable portion or rim 4. The PCB or PCBA is formed from glass fibre reinforced epoxy resin with a copper foil bonded to one or both sides of the PCB. The removable part comprises only the bevelled ring shaped portion, which may be formed of plastic in some embodiments, coupled to the semi-transparent material or lens 10 if present, the PCB 26 for the LED chips, electronic couplers On this case conductive regions for coupling with pogo pin connectors 28 on the main housing) to connect the electronics in the detachable portion to those in the main housing, mechanical couplers to removably attach the detachable portion to the main housing, and the LED chips 6 themselves. No additional structure need be present (and the filter or lens 10 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 may be provided as a bayonet type mount with tabs and slots on the main housing and the detachable portion respectively. Tabs on the main housing are aligned with slots on the detachable portion and the two are pushed together and then turned so that tabs on both portions align to removably fix the detachable portion in place. This means that the detachable portion need only be pushed towards the main housing and then turned to hold the detachable portion 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.

Figures 7A and 7B show the configuration of the detachable portion 4 in a bit more detail. From the outside or from the front (figure 7A) only a thin ring-shaped and bevelled section is visible, along with the lens or transparent material which is also ring shaped and sits within the outer supporting ring. From the back (figure 7B) the PCB 26 and tabs 34 forming part of the bayonet fixings for coupling to the main housing are visible as well as the LEDs 6 which are coupled to the PCB. A plurality of LEDs may be provided all of the way around the rim to provide as consistent an illumination. Between 10 and 40 LEDs may be provided all of the way around the rim, preferably between 20 and 30, and preferably 24 LEDs will be provided to give sufficient consistency to the appearance of the halo of light whilst minimising the cost of production. Figure 7C

IS

illustrates the underside of the main housing without the detachable portion fitted. The connectors 28 are visible, as well as the light guide, and snap-fit mechanism for a functional module.

Between the LEDs in at least one location and in some embodiments in a number of locations (such as spaced out around the ring between each set of six LEDs) are electronic connections for providing a connection between the LED PCBA and the electronics and PSU PCBA within the main housing. Figure 7C shows one possible configuration in which one set of pogo pin connectors (one positive and one negative pin) are included on the main housing. One set connectors is sufficient and using just one saves space on the underside of the detachable portion for LED chips. In one example, pogo pin connectors or other spring-loaded connectors are used to provide the electrical connection. The spring loaded part of the connector are shown provided on the main housing, with mating conductive areas on the detachable portion. Alternatively, the spring loaded connectors may be provided on the detachable portion and conductive regions for mating with these on the main housing. If several connectors are provided around the detachable portion then for each of the connectors separately the spring loaded portion may be located either on the detachable portion or the main housing, however it is preferable for all of the connectors on each of the main housing and the detachable portion respectively to be the same as each other which allows easier replacement of the detachable portion. Preferably, all of the connectors on the detachable portion represent conductive areas which mate with spring loaded connectors in corresponding positions around the main housing. The bayonet-type mechanical fixing on the main housing, if a bayonet fixing is used, will be located such that the detachable portion can be pushed inwards towards the main housing without connection being made between the LED PCBA and the PSU PCBA. Only when the rim is turned to fix it in place using the bayonet fixing is the connection made. This provides for safer installation and helps to maintain a strong connection between the two PCBAs.

The inclusion of a lightweight, removable, and reasonably small-sized rim to which LEDs 6 and LED PCBs 26 are coupled means that this part of the apparatus can be separately replaced. Previously, if a LED chip 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 does not need to be replaced each time an LED chip fails. Instead, the removable rim only is dismounted from the main housing 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 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. As can be seen in figure 8, there is a space 36 above the electronics within the main housing which can be used to double stack the PCBA in the main housing for the inclusion of IOT (internet of things) technology. A Bluetooth connection with the apparatus may be possible. Also shown in figure 8 is the transformer 31 which may be made as a custom fit to the lighting apparatus and so that it can be oriented vertically with the longer side perpendicular to the PCBA as shown. This allows the diameter of the lighting apparatus to be minimised along with the size of the hole in the mounting surface required to fit the unit. The transformer 31 is a step down transformer which converts mains voltage at 240V to 20V. Figure 9 illustrates a simple connection mechanism with the mains power. A matching terminal or plug can be coupled to wires and plugged into or over the terminal 38 shown in the figure in order to provide screw-less connection to the PSU in the main housing. The PSU connector comprises two positive and two negative connectors. This means that the installer is able to conned a number of units in series (via a daisy chain connection) from a single power source which greatly reduces install time. In some embodiments, it is possible to conned up to six units together in this way to draw from a single power source. Figure 9 also illustrates an embodiment of the bayonet connector between the detachable portion and main housing. The rim includes a slot with tabs which can be fitted through slots on a rim extending outwards from the main housing and turned so that they correspond to tabs on the main housing rim and are held in place.

The snap-fit connector for connecting the central functional module with the walls of the cavity of the main housing is shown in figure 10. A blanking cap 22 with tabs 11 for coupling to the groove 13 in the wall of the cavity are shown, and any functional module may include similar tabs. Here the slot is provided on the cavity and tabs on the blanking cap (or functional module) but a slot may be provided on the blanking cap or functional modules and tabs provided which extend from the walls of the cavity if desired. Since it may be more difficult to replace the main housing, however, it is preferable that the tabs which may be more easily broken are on the functional module or blanking cap. This type of fitting allows heavier functional modules to be attached to the lighting apparatus as mentioned, but also means that it is possible for the centre cap to be flush with the walls of the main housing which provides certain aesthetic benefits. Additional support can be provided over and above magnetic connectors if these are used in order to support these heavier modules. Seals 42 may be provided on the apparatus for fire protection as shown in figure 11. A bayonet connection can be used in addition to or instead of the snap-fit connectors if desired.

Figure 12A shows the intensity of the light emitted by the lighting apparatus such as that described above as a function of the distance from a point on the floor and directly underneath the light (point 0,0 on the plot) when the apparatus is mounted at a height of 10 meters. Figure 12B illustrates the beam angle and the luminosity of the beam at different angles. The average beam angle in this case is 106.0 degrees as shown as straight lines on the plot.

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 a detachable portion configured to form a front surface of the apparatus and having a first PCB and illumination means fixedly coupled thereto and 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.
2. A lighting apparatus according to claim 1, wherein the second attachment means comprises a bayonet fitting.IS
3 A lighting apparatus according to any of claims 1 and 2, wherein at least one electrical connector is provided on the main housing and the detachable portion and the connector or connectors on the detachable portion are in contact with a connector or connectors on the main housing to provide an electrical connection between the two when the detachable portion is removably coupled to the main housing.
4. A lighting apparatus according to claim 3, wherein the electrical connector is a pogo pin connector.
5. A lighting apparatus according to any of claims 1 to 4, wherein the front surface formed by the detachable portion is ring-shaped.
6 A lighting apparatus according to any of claims 1 to 5, wherein the PCB and the illumination means are coupled to the rear surface of the detachable portion such that the light is emitted in a direction away from the front surface of the apparatus once installed.
7. A lighting apparatus according to any of claims 1 to 6, wherein the illumination means comprises one or more LED chips.
8. A lighting apparatus according to any of claims 1 to 7, wherein the main housing comprises a light guide to reflect light emitted by the illumination means back towards the front of the housing.
9 A lighting apparatus according to claim 8, wherein the light guide is formed from a reflective polycarbonate.
10. A lighting apparatus according to any of claims 8 and 9, wherein the light guide is configured to direct light through a lens or filter on the detachable portion.
11. A lighting apparatus according to claim 10, wherein the lens or filter is ring shaped.
12. A lighting apparatus according to any of claims 8 to 11, wherein the light guide is configured to reflect light to cover a circular area on the floor of a room when the apparatus is installed on the ceiling of the room.
13. A lighting apparatus according to claim 12, wherein the circular area corresponds to a circular area of the floor doused with water when a fire sprinkler is installed within a cavity in the central housing and is activated.
14. A lighting apparatus according to any of claims 1 to 13, comprising a PCB coupled to the main housing.
15. A detachable portion for a lighting apparatus, the detachable portion comprising: attachment means for removably coupling the detachable portion to the front of a main housing of the lighting apparatus to form a front surface of the lighting apparatus, wherein at least one illumination means and at least one PCB are fixedly coupled to the detachable portion such that the illumination means, PCB, and detachable portion can be removed from the main housing as one piece.
16. A lighting apparatus comprising: a main housing with a first attachment means for securing the apparatus to a mounting surface; a light guide coupled to the main housing and configured to reflect light emitted by illumination means towards the front surface of the housing to cover a circular area on the floor of a room when the apparatus is installed in the ceiling of the room; a fire sprinkler module configured to be coupled to the main housing, wherein the area of the floor of the room doused with water when the sprinkler is activated corresponds to the circular area.