GB2416200A

GB2416200A - Picture Light Having Movable Light Modules

Info

Publication number: GB2416200A
Application number: GB0412234A
Authority: GB
Inventors: Kenneth Miller
Original assignee: BESPOKE LIGHTING Ltd
Priority date: 2004-06-02
Filing date: 2004-06-02
Publication date: 2006-01-18
Also published as: GB0412234D0; GB2416200A8

Abstract

A picture light 10 comprising a body 12 and a support 16 for mounting on or to a surface, the body 12 defining an illumination aperture 24 and a space 19 to receive a lighting bus 32, the lighting bus comprising a power rail 32 and means for receiving a light module 34 whereby the power rail 32 provides power to a light module 34 received on the bus regardless of the position of the module on the bus.

Description

1 2416200 Picture Light This invention relates to lights, and in

particular, but not exclusively, to a light for illuminating a wall mounted picture, or other work of art.

Usually, a room which houses pictures, paintings, or similar works of art will have standard ceiling mounted lighting such as bulb lighting, striplights or spotlights.

However, ambient room lighting such as this is often insufficient to do justice to the artwork.

It is usual therefore, particularly in larger rooms such as those commonly found in stately homes, art galleries and museums, to install additional lighting which illuminates the artwork in addition to the surrounding ambient lighting. It is known therefore to provide a wall or frame mounted light which illuminates a specific work of art hung on the wall. Such a light serves the purpose of illuminating the work of art so as to optimise its display to the viewer. It is typical to use incandescent lamps as the light source. However, there are numerous problems associated with this form of lighting. In particular, incandescent lamps produce excessive heat which may in time degrade the illuminated painting.

This problem is partially overcome by the use of high output fluorescent tubes.

However, this type of light also has associated problems, including the emission of ultra-violet (UV) radiation which often leads to degradation of the painting. Whilst this problem is overcome to some extent by the introduction of a W filter, this leads to increased,cost and complexity of the product as well as a reduction in light intensity.

Furthermore, a secondary filter is required since the colour of the light produced by the fluorescent tubes is not ideal for illuminating paintings.

A further problem associated with the fluorescent tube lamp is that the horizontal dimensions of the lamp are limited to the maximum achievable length of the tube. In addition, the horizontal spread of the light produced by the tube is not readily controllable after installation of the light.

Yet another problem with both incandescent lamps and fluorescent tube lights is that the heat produced by the lights and their associated hardware can pose a fire hazard if not carefully managed. Furthermore, these types of lights tend to be heavy, which places limitations on their size and thereby light output, as well as complicating installation of the light.

Lastly, to achieve the required light intensity these types of lights are commonly large and as a result can restrict the view of the painting which is being illuminated.

It is an intention of the present invention to provide an improved picture light.

In accordance with the invention there is provided a picture light comprising a body and a support for mounting on or to a surface, the body defining an illumination aperture and a space to receive a lighting bus, the lighting bus comprising a power rail and means for receiving a light module whereby the power rail provides power to a light module received on the bus regardless of the position of the module on the bus.

Advantageously, these features allow the picture light increased flexibility in orientating the light to best illuminate the picture.

Preferably, the lighting bus is capable of rotation relative to the body.

Advantageously, this feature allows the light modules to be rotated so as to direct the light path onto the painting as required.

Further preferably, the, or each, light module is capable of lateral movement relative to the lighting bus.

This feature of the invention permits further fine-tuning of the spread of light produced by the picture light. This is not possible with an incandescent tube, since the tube cannot move laterally in the light housing. A further advantage of this feature of the invention is that fine-tuning of the light is possible after installation of the picture light on the wall.

Preferably, the lighting bus acts as a heat sink.

Further preferably, the body houses a temperature sensor which is electrically coupled to a controller, the controller being capable of shutting down electrical supply to the light modules when a temperature within the body exceeds a predetermined level.

Yet further preferably, the picture light includes a power unit for providing an electrical supply, the power unit having a temperature sensor which is electrically coupled to a controller, the controller being capable of shutting down electrical supply to the light modules when a temperature within the body exceeds a predetermined level.

Advantageously, these features reduce the risk of the light causing a fire since the level of heat dissipated onto the picture is reduced.

In a second aspect of the invention there is provided a picture light comprising at least one light emitting diode.

Advantageously, LED's are available in a range of colours and light intensities which means that a bespoke colour and light output may be generated for a specific application, negating the requirements for a colour filter.

Of further advantage is that the level of heat generated by an LED for a given light output is considerably lower than an incandescent lamps or fluorescent tubes. Furthermore, LED's do not emit ultraviolet radiation which eliminates the need for a UV filter.

The invention will now be described by way of the following non-limiting example with reference to the figures, in which: Fig. 1 is a rear isometric view of a picture light according to the present invention; Fig. 2 is a front isometric view of the picture light of Fig.1; Fig.3 is an exploded rear isometric view of the picture light of Fig.1; Fig.4 is an exploded rear isometric view of the picture frame of Fig.1; Fig.5 is a rear isometric view of three LED modules in accordance with the present invention; Fig.6 is a rear isometric view of a subassembly of the present invention including the three LED modules of Fig.5; Fig.7 is a rear isometric view of a lighting bus in accordance with the present invention carrying the subassembly of Fig.6; Fig.8 is a front isometric view of one of the LED modules of Fig.5; Fig.9 is an end view of the lighting bus of Fig.7 shown in isolation, for clarity With reference to Figs.l and 2, the picture light 10 has a main body 12 which is fixed to a base 14 by means of a support arm 16. The main body 12 is attached to the support arm 16 by an articulated joint 28 at its shoulder 30. It is conceivable that this articulation could be achieved by a ball and socket joint, resiliently flexible cable, or other flexible mounting means.

The support arm 16 achieves a 90 degree angular displacement between the shoulder and the base 14, although it is perfectly conceivable within the scope of the invention that an alternative support arm geometry be provided so as to allow mounting of the base 14 to a ceiling or other feature of a room rather than to the wall on which the picture is hung.

The main body 12 is formed from a hollow central section 18 enclosed at a first end by a first end plate 20 and at a second end by a second end plate 22. The central section 18 has a substantially circular crosssection so as to form a cylindrical cavity 19. With reference briefly to Fig.4, the central section 18 defines an aperture 24 which runs substantially the length of the central section 18. Flanking the front side of the aperture 24 is a lip 26, the purpose of which is to shield the viewer from the light produced by the picture light.

With reference to Figs. 3 and 4 the first and second end plates 20, 22 define an outer circular profile 48 and an inner circular profile 50, the outer profile 48 being flush with the exterior surface of the central section 18, and the inner profile 50 being flush with the interior surface of the central section 18. The fit between the end plates 20, 22 and the central section 18 is such that the end plates 20, 22 are able to rotate with resistance against the central section 18.

The central section 18 houses a lighting bus 32 which has a base portion 36 and first and second side walls 38, 39. The lighting bus 32 is retained within the central section 18 by means of the first and second end plates 20, 22. With reference to Fig.3, the second end plate 22 includes a projection 44 which is fixed thereto by means of screw 46 (see Fig.4).

The projection 44 is shaped so as to fit within the end profile of the lighting bus 32 as defined by its base portion 36 and side walls 38, 39. Likewise, the first end plate 20 also defines a projection 44 shaped to fit the outer profile of the other end of the lighting bus 32.

In such a manner, the first and second end plates 20, 22 are rotationally fast with the lighting bus 32.

The lighting bus 32 retains a power rail in the form of printed circuit board (PCB) 52 and a number of LED modules 34. The PCB 52 is arranged against the base portion 36 of the lighting bus 32 in a PCB groove 45 defined by the side walls 38, 39 of the lighting bus 32 (see Fig.9). With reference to Fig.6, the PCB 52 defines two copper tracks 54a and 54b the purpose of which will be described in further detail shortly. In addition to the PCB groove 45, the side walls 38, 39 define a first groove 40 and a second groove 42. The first groove 40 is provided for retaining the LED modules 34 and is defined by a first rail slot 41 in the first side wall 38 and a second rail slot 43 in the second side wall 39, the second rail slot 43 being deeper than the first rail slot 41.

The second groove 42 is provided in the lighting bus 32 for retaining an optical filter for use in conjunction with the LED modules 34. Such a filter may be used to diffuse the light provided by the LED's or to achieve a particular colour or spread of colour.

The lighting bus 32 is formed from extruded aluminium although it is conceivable that it could be produced by alternative means such as casting.

With reference to Fig.8, the LED module 34 has a head portion 35 and an engagement portion 37. The head portion 35 carries the LED 60 and the engagement portion 37 defines a first runner 56 and a second runner 58, the first runner 56 having a greater depth than the second runner 58. The engagement portion 37 also defines a pair of brush contacts 62 sprung so as to be biased away from the engagement portion 37.

It will be appreciated that each LED module 34 may contain a number of LED's of the same, or different colour. Similarly, each LED module may contain a bank of differently coloured LED's.

The LED modules 34 are held in position on the lighting bus 32 by the first and second slots 41, 43. The first runner 56 runs along the first rail slot 41 and the second runner 58 runs along the second rail slot 43 (see Fig.7).

When the LED modules 34 are in position on the lighting bus 32 the brush contacts 62 are brought into contact with the copper tracks 54 on the PCB 52. The copper tracks 54 provide electrical power to each of the LED modules 34. In such a manner the LED modules 34 are retained within the lighting bus 32 such that they are moveable along groove 40 of the lighting bus 32, but will remain in position under the force of the sprung contacts 62. It will be appreciated that an LED module will receive power from the copper tracks 54 irrespective of its horizontal position within the lighting bus 32 by virtue of the contact between the brush contacts 62 and the copper tracks 54.

During assembly of the picture light 10, a predetermined selection of LED modules is slotted into the first groove 40 of the lighting bus 32 so that the brush contacts 62 make electrical contact with the copper tracks 54 of the PCB 52. The lighting bus 32 is inserted into the central section 18 of the main body 12 so that an end of the lighting bus 32 accepts the projection 44 and abuts the first end plate 20. If required, a light filter, or diffuser, is inserted into the second groove 42. The second end plate 22 is then fitted into the other end of the central section 18, and the screw 41 is tightened to fix the assembly. The main body 12 is attached to the support arm 16 at the shoulder 30 and the subassembly is then mounted onto the base 14 which has previously been attached to the wall on which the picture to be illuminated is hung.

It is then possible to fine tune the direction of the light path by rotating the first and second end plates 20, 22 to allow for the vertical position of light, and by moving the LED modules within the lighting bus to allow for horizontal position of the light path.

Whilst the figures show a lighting bus which accommodates three LED modules, it is within the scope of the invention to provide a lighting bus which accommodates substantially more LED modules. The width of each light is limited only by the maximum extrusion length of the lighting bus. However it is conceivable that lengths of extrusion could be joined by adhesive or welding to produce a longer lighting bus.

It is also conceivable that the lighting bus accepts forms of lighting module other than LEDs, for example incandescent bulbs, or fluorescent tubes.

Since the size and weight of the unit is substantially reduced compared to an incandescent lamp or fluorescent tube of similar light output, the unit intrudes far less on the picture.

Furthermore, since the light preferably runs off a Sv DC supply, the number of LED modules which can be accommodated by a single light unit is not limited by a conventional llOv or 240v AC supply. A power unit is provided which preferably transfers the AC supply into the 5v DC supply. The power unit can be concealed above, behind, or remote from, the picture.

Claims

Claims 1. A picture light comprising a body and a support for mounting on

or to a surface, the body defining an illumination aperture and a space to receive a lighting bus, the lighting bus comprising a power rail and means for receiving a light module whereby the power rail provides power to a light module received on the bus regardless of the position of the module on the bus.
2. The picture light according to claim 1 wherein the lighting bus is capable of rotation relative to the body.
3. The light according to any preceding claim wherein the, or each, light module is capable of lateral movement relative to the lighting bus.
4. The picture light according to any preceding claim wherein the lighting bus has a base and two side walls.
5. The picture light according to claim 4 wherein the power rail is retained by the lighting bus at a position adjacent the base.
6. The picture light according to claim 5 wherein the, or each, light module is retained by the side walls of the lighting bus, such that the, or each, light module is in contact with the power rail.
7. The picture light according to any one of claims 4 to 6 wherein the lighting bus is capable of retaining a light filter at a position on the side walls distal the base.
8. The picture light according to any preceding claim wherein the power rail is a printed circuit board.
9. The picture light according to any preceding claim wherein the body has a cylindrical portion closed off by first and second end plates which each have an inwardly facing projection for engaging respective ends of the lighting bus, so that rotation of the end plates causes rotation of the lighting bus.
10. The picture light according to any preceding claim wherein the light module acts as a heat sink.
11. The picture light according to any preceding claim wherein the body acts as a heat sink
12. The picture light according to any preceding claim wherein the body houses a temperature sensor which is electrically coupled to a controller, the controller being capable of shutting down electrical supply to the light modules when a temperature within the body exceeds a predetermined level.
13. The picture light according to any preceding claim wherein the light includes a power unit for providing an electrical supply, the power unit having a temperature sensor which is electrically coupled to a controller, the controller being capable of shutting down electrical supply to the light modules when a temperature within the body exceeds a predetermined level.
14. The picture light according to any preceding claim wherein the light module is a light emitting diode (LED) module.
15. A picture light comprising at least one light emitting diode.
16. The picture light according to claim is wherein the LED, or LED's, are selected to provide white light.
17. The picture light according to claim 15 or 16 wherein the LED, or LED's, are selected to eliminate ultraviolet light.
18. The picture light according to any one of claims 15 to 17 wherein the LED, or LED's, form part of an LED module.
19. The picture light according to claim 18 wherein the LED module is retained on a lighting bus.