GB2504686A

GB2504686A - A downlighter or uplighter light source

Info

Publication number: GB2504686A
Application number: GB1213903.6A
Authority: GB
Inventors: Gary Cream; Andrew Kilborn
Original assignee: ORLUNA LED TECHNOLOGIES Ltd
Current assignee: ORLUNA LED TECHNOLOGIES Ltd
Priority date: 2012-08-06
Filing date: 2012-08-06
Publication date: 2014-02-12
Also published as: GB201213903D0

Abstract

A downlighter / uplighter light source which comprises one or more light emitting diodes (LEDs) 9 and an aspheric lens 7 arranged to focus the light emitted from the LED(s). The lens is surrounded by an annular lip 8 and its rear surface is substantially planar and is translucent. The light source is cooled by a heat sink which comprises a plurality of fins 12. The light source further comprises a bezel to facilitate the recessing of the unit.

Description

tM:;: INTELLECTUAL !. .*. PROPERTY OFFICE Application No. 0B1213903.6 RTM Date:7 September 2012 The following terms are registered trademarks and should be read as such wherever they occur in this document: Cree Intellectual Properly Office is an operaling name of Ihe Patent Office www.ipo.gov.uk Light source The present disclosure relates to a light source, more particularly to an LED light source that is configured as a downlighter or uplighter.

Downlighters have become increasingly popular in recent years as a means for lighting both domestic and commercial properties. Such downlighters are frequently found mounted in recesses in ceilings. Uplighters have the same construction as downlighters but are mounted in recesses in floors or other surfaces with the light source pointing up rather than down. The description herein of downlighters is equally applicable to uplighters.

Downlighters have traditionally been provided with an incandescent or halogen light bulb as the light source. Downlighters featuring halogen bulbs, which feature a built in reflector, have proved particularly popular, since they provide a narrow beam of bright light.

Recently, LED downlighters, which use one or more LED5 (light emitting diodes) as the light source have started to replace the halogen downlighters, since the LED(s) have an extended lifetime over halogen bulbs and use less power.

A problem with these LED downlighters, however, is that they are not effective for providing a narrow beam of light. Where a narrow beam of light is required, users have had to continue to use less efficient halogen downlighters or seek less elegant alternative solutions. A particularly narrow beam is often desired in high value residential properties or in hotels or other commercial properties, where it is desired to provide a highly controlled lighting environment. Multiple downlighters may be provided with each of the downlighters arranged to light a specific artwork, ornament or region of the room.

Various reflector designs have been presented in a bid to provide LED downlighters that provide a narrow beam, however, these have proved largely ineffective.

The present invention arose in a bid to provide an improved light source, specifically for use as a downlighter or uplighter, which offers superior lighting performance whilst utilizing one or more LED5.

According to the present invention, in a first aspect, there is provided a light source comprising a downlighter or uplighter, which comprises one or more light emitting diodes (LED5) and a lens arranged to focus the light emitted from the LED(s), wherein the lens is an aspheric lens.

Non-limiting embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a partial exploded view of light source according to the present invention; Figure 2 shows a sectional view of the assembled components of Figure 1; Figure 3 shows a perspective view of the light source of Figure 1 in a fully assembled state; and Figure 4 shows a side view of the light source of Figure 3 with some detail hidden for clarity.

Referring to Figures ito 4, there is shown a light source according to a first embodiment of the present invention. The light source is configured as a downlighter/ uplighter. Note that the configuration of the light source as a downlighter or an uplighter is entirely dependent on the surface in which the light source is mounted. If mounted such that it faces down in use (such as by mounting in a ceiling) it will comprise a downlighter. If mounted such that it faces up in use (such as by mounting in a floor) it will comprise an uplighter.

Generally, the light source comprises a body 1, an LED 2 and a lens 3, which together form a light engine, and a bezel 4.

The lens is arranged to focus the light emitted from the LED and comprises an aspheric lens. The lens and LED are maintained in spaced relation to one another. The light beam emitted by the light source is predetermined in dependence on the lens's asphere surface profile and the spacing of the LED from the lens.

A range of different light sources in accordance with the present embodiment may be provided, each of which provides a different beam, by providing each light source with a differently profiled asphere and/or a different spacing between the LED and the lens.

The light source does not comprise a reflector. Accordingly, in contrast to prior art LED downlighters/uplighters the light beam emitted by the light source is not dependent upon a reflector or any other element behind the LED. This has the advantage that the beam may easily be altered by swapping the lens for a different lens with a different surface profile. The lens may further be swapped with a lens of a different colour, or otherwise.

A particular benefit of the light source of the present embodiment is that a narrow beam may be provided by use of the aspheric lens. A particularly favoured beam is a 10 degree beam. A specific arrangement in accordance with the present embodiment that is configured to achieve such a beam is described below, by way of non-limiting example.

The lens is circular in plan view and comprises a rear face 6, which is planar and faces the LED, and the asphere (aspheric domed portion) 7, which forms a front face of the lens from which light is emitted. The lens is further provided with an annular lipS, which surrounds the asphere. The annular lip is flush with the rear face and continuous therewith.

It should be noted that the lens need not limited to the aforementioned arrangement, however, such an arrangement is preferable since the construction of the light source may be simplified by such a lens arrangement. The lens is transparent except for the rear face, which is treated to be translucent. The rear face is preferably surface treated such that it has a fine textured pattern. Alternatively, the rear face may be provided with a suitable surface coating. Any suitable means of rendering the rear face of the lens translucent may be used. In alternatives, the lens may not feature a translucent rear face. However, a particular benefit of rendering the rear face translucent is that the profile of the LED is not projected by the light source. The lens is preferably of unitary construction. An example material for manufacture of the lens is crown glass, which has a refractive index of 1.52.

The LED is preferably provided as an LED chip 9 that is mounted to a circuit board 10.

An example LED that is suitable is a Cree XML LED with a star board mounting. As will be readily appreciated by those skilled in the art numerous alternative suitable LEDs may be used. The LED is mounted on the optical axis X-X of the lens, i.e. the LED is mounted in alignment with the center of the lens.

The body 1 comprises a heat sink. The heat sink comprises a rear portion 11, which comprises a plurality of fins 12 for dissipation of heat generated by the LED(s), and a front portion 13, which is generally cylindrical and comprises a floor 14 and an annular side wall projecting from the floor. The floor is preferably substantially planar, as shown. As shown in Figure 2, the LED is mounted to the floor. The LED is mounted directly to the floor using adhesive. The LED may be mounted to the floor using any means so long as the LED is in thermal communication with the heat sink. In alternatives the LED may be mounted to the floor indirectly. The floor may not be planar.

The heat sink is preferably of unitary construction. The heatsink is preferably aluminium.

A wiring loom 5 is provided, which provides an electrical connection to the LED.

The lens has substantially the same footprint as the annular wall of the heatsink.

The annular lip of the lens preferably has a greater width than the wall thickness of the annular side wall of the heatsink, as shown in Figure 2. By virtue of this arrangement the asphere is inwardly spaced from the annular side wall of the heatsink.

The lens is supported by the annular side wall of the heatsink. The rear face of the lens may be in direct contact with the annular side wall of the heat sink, as shown in Figure 2. With the lens supported by the annular side wall and the LED mounted to the floor of the heatsink, the distance between the lens and the LED, specifically the distance between the rear face of the lens and the front face of the LED is fixed at a predetermined distance. The rear face of the lens may be spaced from the front face of the LED by at least 5mm, preferably at least 10mm.

S

The bezel 4 is connected to the body. The bezel, the heat sink and the lens are coaxial. They are all arranged along the X-X axis, as shown in Figure 2. The heat sink comprises a substantially cylindrical rear portion 16, which is coaxial with the lens and the heatsink and which extends to a level beyond the tip of the lens, as shown in Figures 3 and 4, such that the lens is recessed from the front of the bezel. The substantially cylindrical rear portion preferably has a larger diameter than the annular side wall, surrounds at least a portion of the annular side wall and extends forward of the annular side wall, as shown, such that the whole of the lens (which is supported by the annular side wall) lies within the cylindrical rear portion of the bezel. The substantially cylindrical rear portion terminates forward of the lens in a planar ring 17. The planar ring provides a fascia forthe light source and is arranged to engage the front face of a surface provided with a recess, around the recess, when the light source is mounted in the recess in the surface. In use, the light source is mounted in a recess provided in a surface, such as a ceiling or floor. The light source is arranged such that the tip of the lens is recessed from the front face of the surface in which it is mounted.

The cylindrical rear portion of the bezel may be provided with fixing means (not shown) for engaging with corresponding fixing means on the heatsink, for example screw threads, for fixing the bezel to the heatsink. The cylindrical rear portion of the bezel may also be provided with fixing means, such as an inwardly protruding rim, for engaging a front surface of the annular rim of the lens to fix the lens to the heat sink. With such an arrangement, removal of the bezel will allow for simple replacement of the lens.

In a specific, non-limiting, arrangement configured in accordance with the above described embodiment, as seen most clearly in Figure 2, the lens has an overall diameter of 53 mm (including the annular rim), the asphere has a diameter of 50mm, and the lens has an overall depth (in the axial direction X-X) of 24.24mm. The rear face of the lens is spaced from the front face of the LED by 14.5mm. The LED is a Cree XML LED. This arrangement provides a 10 degree beam.

As will be readily appreciated alternative configurations may be provided which provide a 10 degree beam or provide beams of different angles.

Whilst in the above described embodiment only a single LED is provided, in alternatives two or more LED5 may be provided. Numerous other variations, within the scope of the proceeding claims, will be appreciated by those skilled in the art following this

disclosure.

Claims

Claims 1. A light source comprising a downlighter or uplighter, which comprises one or more light emitting diodes (LED5) and a lens arranged to focus the light emitted from the LED(s), wherein the lens is an aspheric lens.
2. A light source as claimed in Claim 1, wherein a single LED only is provided.
3. A light source as claimed in Claim 2, wherein the LED is mounted on the optical axis of the lens.
4. A light source as claimed in any preceding claim, wherein the lens has a substantially planar rear face, which is arranged to face the LED(s).
5. A light source as claimed in any preceding claim, wherein the rear lace is translucent.
6. A light source as claimed in Claim 5, wherein the rear lace is rendered translucent by a surface treatment or by application of a translucent layer thereto.
7. A light source as claimed in any preceding claim, wherein the lens and LED(s) are maintained in spaced relation to one another.
8. A light source as claimed in any preceding claim further comprising a body, wherein the LED(s) and lens are mounted to the body.
9. A light source as claimed in Claim 8, wherein the body comprises a heat sink.
10. A light source as claimed in Claim 9, wherein the heat sink comprises a rear portion, which comprises a plurality of fins for dissipation of heat generated by the LED(s), and a front portion, which is generally cylindrical and comprises a floor and an annular side wall projecting from the floor, wherein the side wall maintains the lens in spaced relation to the LED ( s).
11. A light source as claimed in Claim 10, wherein the floor is substantially planar.
12. A light source as claimed in Claim 100111, wherein the LED(s) is mounted to the floor.
13. A light source as claimed in Claim 10, 11 or 12, wherein the heat sink is of unitary construction.
14. A light source as claimed in any preceding claim, wherein the lens comprises an asphere and an annular lip that surrounds the asphere.
15. A light source as claimed in Claim 14, when dependent on any of Claims 10 to 13, wherein the annular lip is supported by the annular side wall of the heat sink.
16. A light source as claimed in any of Claims 8 to 15 further comprising a bezel, which is connected to the body.
17. A light source as claimed in Claim 16, wherein the bezel comprises a substantially cylindrical rear portion, which is coaxial with the lens and extends to a level beyond the tip of the lens.
18. A light source as claimed in Claim 17, when dependent on any of Claims 10 to 17, wherein the substantially cylindrical rear portion has a larger diameter than the annular side wall, surrounds at least a portion of the annular side wall and terminates at a level beyond the tip of the lens.
19. A light source as claimed in Claim 18, wherein the substantially cylindrical rear portion terminates in a planar ring, which is arranged to engage the front face of a surface provided with a recess, around the recess, when the light source is mounted in the recess in the surface.
20. A light source as claimed in any preceding claim, which is adapted to provide a 10 degree beam of light.
21. A light source as claimed in any preceding claim, wherein the asphere of the lens has a diameter of 50mm.
22. A light source substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.