GB2313184A

GB2313184A - Reflector Lamp)

Info

Publication number: GB2313184A
Application number: GB9610263A
Authority: GB
Inventors: Andrew Beresforde
Original assignee: BRITISH ELECTRIC LAMPS Ltd
Current assignee: BRITISH ELECTRIC LAMPS Ltd
Priority date: 1996-05-16
Filing date: 1996-05-16
Publication date: 1997-11-19
Also published as: GB9610263D0

Abstract

An eyeball fitting is adapted for use with a compact fluorescent lamp and has a mounting device and collar member for securing around an aperture, a support frame and lamp holder for pivoting with respect to the collar member and a reflector secured to the lamp holder. The reflector has an axial extent substantially equal to or greater than that of the compact fluorescent lamp, so that the lamp does not project from the fititng.

Description

LIGHTING DEVICE AND REFLECTOR THEREFOR The present invention relates to the field of lighting devices, and especially, but not exclusively, to lighting devices employing so-called compact fluorescent lamps.

For some while it has been desirable to reduce consumption of energy and to reduce maintenance of lighting devices by substitution of low energy lamps for conventional incandescent lamps. Because the geometry of such low energy lamps is frequently different to the geometry of incandescent lamps, direct substitution of one type of lamp for the other may give rise to undesirable changes both in the look of the lighting device and in the distribution of light from the lighting device.

Among the types of lighting device which have become popular in recent years are so-called "spotlights" and so-called "eyeball lights". These lighting devices have been designed to use reflector-type incandescent lamps, i.e. lamps having an integral reflective portion for directing the light output from the lamp in a predetermined fashion. The absence of a reflector in the light fitting itself means that direct substitution of a low energy lamp, also lacking a reflector, for the conventional incandescent lamp gives a considerably different light distribution.

It is therefore desirable to provide a light fitting which generally resembles an eyeball fitting or which resembles a spotlight fitting which includes an integral reflector and thus allows use of a compact fluorescent lamp.

According to the present invention there is provided a reflector for a compact fluorescent lamp, the reflector having a generallycircular cross-section centred upon an axis of circular symmetry, the axial extent of the reflector being at least equal to the axial length of the compact discharge lamp, the cross-section varying along the axis of symmetry to provide a desired directive characteristic, the reflector having, at one end thereof, engagement means for securing the reflector to a lamp socket for supporting the lamp.

Preferably the engagement means comprises a cylindrical portion having an internal thread for engagement with an external thread on the outer periphery of the lamp holder.

Embodiments of the present invention will now be described with respect to the accompanying drawings in which: Figure 1 shows a perspective view from one end of a reflector.

Figure 2 shows a perspective view from the other end of the reflector of Figure 1.

Figure 3 shows a partially cut away perspective view of an eyeball lighting device.

Referring to Figures 1 and 2, a reflector has a wall defining a reflector surface (1) which is disposed about an axis of symmetry (2). The reflector (10) has a first, smaller, open end (3) and a second, larger open end (4). The reflective surface (1) is formed by the inner surface of a thin metal sheet member (5) which forms the majority of the reflector (10). The metal sheet member (5) is formed to have a first generally cylindrical portion (6) which defines the larger opening (4) and which extends into a tapering portion (7) followed by a second generally cylindrical portion (8). At the larger opening (4), the sheet member extends radially outwardly to define an annular flange (9). The end of the second generally-cylindrical portion (8) of the sheet member (5) is secured to a collar member (12) which is provided with an internally threaded portion (13) adapted to engage with the external threads of a lamp socket. The length of the reflector is such that, when the reflector is secured to an associated lamp holder, a compact fluorescent lamp engaged in the lamp holder is entirely within the confines of the reflector (10).

Figure 3 shows the reflector (10) secured to a lamp holder (20) in an eyeball lighting device (100). The eyeball lighting device further comprises an annular face plate (30) which is disposed radially about a band member (31). The inner surface of the band member (31) is concave in the axial direction of the lighting device and is engaged by two spring plungers (40) which are borne in a substantially annular carriage member (41) supported within the periphery of the band member (31). In plan, the spring loaded plungers are, as is well known in the art, disposed diametrically opposite one another. Depending from the carriage member (41) is a metal strip member (32) which has two parallel shank portions (33,34) and a linking portion (35) which supports the lamp holder (20). The length of the shank portions (33,34) is selected so that the reflector (10) does not extend beyond the face plate (30). The spring plungers, again as is well known in the art, allow the lamp holder with its associated support strip (32) and the carriage member (41) to pivot with respect to the plane of the face plate (30) away from the normal position in which the axis of a lamp inserted into the lamp holder is perpendicular to the plane of the face plate (30), to other orientations. This provides a beam of light which may be directed as required by the user.

Although the reflector (10) has been shown in the context of an eyeball lighting device, it is equally applicable to other lighting devices in which the reflector is secured directly to the lamp socket. One example of this would be the use in a socalled "spotlight".

In some applications, the collar member (12) is loosely secured to the metal sheet portion (5) so as to allow mutual rotation between the two. This is advantageous where removal of the reflector should not be facilitated.

However, in other embodiments the collar member (12) is rotationally secured to the metal sheet member (5) so that hand pressure to rotate the member (5) causes the collar member (12) likewise to rotate. As will be clearly understood by one skilled in the art, this allows hand pressure to rotate the collar member (12) which, being secured by screw threads to the lamp holder, causes the reflector to translate relative to the lamp holder, and relative to an inserted lamp. Such translation causes a change in the focus effect caused by the reflector such that light emanating from the lighting device is more focused, and less evenly distributed, or less focused and more evenly distributed. Such an effect may be especially desirable in spotlights, and also finds application in lighting devices which do not employ compact fluorescent lamps, for example those which employ ordinary, non reflector, incandescent lamps.

As described, the reflector has circular symmetry about the axis (2). However, other shapes - eg elliptical cross-sections - may be desirable. The reflector is shown as a two-piece component.

It may be desirable to provide an integral reflector portion and collar portion. The described metal structure may be replaced by metallised or otherwise reflective plastics materials, or other constructions may be used.

Claims

CLAIMS:

1. Lighting apparatus adapted for use with a compact fluorescent lamp comprising a mounting device for securing peripherally around an aperture in a surface, a collar member fixed to said mounting device, a support frame member mounted on said collar member for pivoting with respect to said collar member, and a lamp holder secured to said support frame member, and a reflector secured to said lamp holder to pivot with said lamp holder, the axial extent of said reflector being substantially equal to or greater than an axial length of the compact fluorescent lamp, whereby said apparatus is an eyeball fitting.

2. The lighting apparatus of claim 1 wherein the reflector has a generally circular cross-section centered upon an axis of circular symmetry.

3. The lighting apparatus of any of claims 1 or 2, wherein the cross-section of the reflector varies along said axis of symmetry to provide a desired directive effect.

4. The lighting apparatus of any one of the preceding claims wherein the reflector narrows at one end to form a cylindrical portion having an internal thread for engagement with an external thread of the outer periphery of the lamp holder.

5. The lighting apparatus of any one of claims 1 to 3 wherein the reflector is secured to the lamp holder via a separate collar member, whereby rotation of said reflector is not transferred to said separate collar member.

6. The lighting apparatus of any preceding claim wherein the support frame member has two substantially parallel shank portions and a linking portion for supporting said lamp holder, wherein the shank portions have a length selected such that the reflector does not extend beyond said mounting device.

7. Lighting apparatus constructed and arranged substantially as herein described with reference to and as shown in the accompanying drawings.