GB2114278A

GB2114278A - Panel lighting apparatus

Info

Publication number: GB2114278A
Application number: GB08203106A
Authority: GB
Inventors: Robert Alan Yates
Original assignee: FORECOURT SUPPORT Ltd
Current assignee: FORECOURT SUPPORT Ltd
Priority date: 1982-02-03
Filing date: 1982-02-03
Publication date: 1983-08-17

Abstract

A light box 3 is fronted by a translucent display panel 22 and includes lamps, such as fluorescent tubes, to illuminate the panel. At least the rear inside surface of the light box is covered with a diffraction foil 30 which returns light toward the front panel and which is in effect a combination of mirror and diffuser in the form of multiple Fresnel lenses. The diffraction foil greatly improves lighting efficiency allowing a lesser number of lamps to be used in a given light box. Two groups of lamps in separate energising circuits can be provided, one being used normally and the other providing standby in case of failure in the one group. <IMAGE>

Description

SPECIFICATION Panel lighting apparatus This invention relates to panel lighting apparatus such as is used for shop facias, filling station forecourt canopies, and other applications, whether indoors or outdoors.

Panel lighting apparatus employs a translucent front panel which may or may not carry indicia, and concealed illumination behind it.

Commonly this illumination takes the form of fluorescent strip lighting, with the tubes closely spaced so as to obtain an effect of even illumination on the panel.

In accordance with the invention, reflection and diffusion means are arranged in conjunction with the illumination means to return light directed rearwardly from the illumination means back towards the front panel. This increases the amount of light reaching the front panel, and helps to give more even illumination.

One convenient form of reflection and diffusion means consists of diffraction foil, which is in effect a combination of a mirror and a diffuser in the form of a multiplicity of Fresnel lenses. A suitable diffraction foil is sold by Intra Plastics Limited in United Kingdom or by Coburn in United States, and consists of an embossed clear P.V.C. sheet with a coating of aluminium on the back. A very large proportion of the light reacing the diffraction foil is returned, but it is returned in a diffused form.

By use of the diffraction foil it becomes possible to reduce the amount of illumination considerably. In a typical installation, only half the number of fluorescent tubes need be used. This can lead to economy in first cost and running cost, but it also makes it possible to arrange two systems of fluorescent tubes, one interleaved with the other, so that if a tube fails on the first system, the first system can be switched over to the second. An existing four-tube system can be rewired to make two two-strip systems, one acting as a spare.

One preferred embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, which shows in sectional perspective part of an edge of a forecourt canopy with a panel lighting display fixed to it.

Referring to the drawing, the canopy has a girder 1 extending around its edge: this is shown as a channel section with a web 2 facing outward. A light box designated generally 3 is secured to the girder 1 along the edge of the canopy. The light box 3 comprises a pair of similar aluminium extrusions 4, 5 at the top and bottom secured by pop rivets 6 to the upper and lower flanges 7, 8 of the girder 1. Double-sided foam adhesive strips 9 extend between the aluminium extrusions 4, 5 and the respective girder webs 7, 8 in way of the rivet 6.The extrusions 4, 5 each include a flat base 11, an intermediate upstanding flange 12, and a re-entrant front flange 1 3. The flanges 1 2 are secured to the girder web by pop rivets 1 4. Z-section aluminium extrusions 1 6 have flanges secured to the bases 11 by pop rivets 1 7. The re-entrant portions 1 8 of the front flanges 13, and the forward extending flange portions 1 9 of the Zsection extrusion 1 6 carry rubber beads 20 sealing against a front translucent facia panel 22. The beads 20 are in firm sealing engagement with the panel 22. A strip 23 along the top of the panel engages over the top front bead 20 and the panel to provide positive support for the bracket.Brackets 25 within the light box carry framework 26 spaced forwardly from the girder web 2 and the framework 26 carries four fluorescent tubes of which only one is shown diagrammatically at 27. The girder web 2 and preferably the inner surface of the upper and lower extrusions 4, 5 are covered with diffraction foil, adhesively secured and shown diagrammatically at 30: this foil is as above described.

The diffraction foil has been found to increase surprisingly not only the level of illumination obtained at the front of the acrylic panel 22, but also the evenness of this illumination. Because of this it has been found sufficient to illuminate the panel with only two fluorescent tubes. While the arrangement could have been designed with only two such tubes, it will commonly be convenient to include four tubes as shown, with the first and third, and second and fourth, connected in two separate and independent circuits. Illumination can then be provided by one circuit, the other acting as a spare in case a tube of the first circuit should become defective.

Thus, if it is decided not to economise in first cost by supplying only two tubes and their support fixtures, the advantage is obtained, besides saving fuel costs, in doubling the time between maintenance calls due to light failure.

Existing panel lighting apparatus can be adapted to make use of the invention.

It will be seen that the light box illustrated makes use of the canopy girder as a back. If desired, the light box could be self-contained, providing its own back. The foam strips illustrated at 9 provide a waterproof joint.

1. Panel lighting apparatus comprising a light box structure including a translucent panel through which light is to be radiated, illumination means within the structure for generating light to irradiate the panel and reflection and diffusion means arranged to return light directed away from the panel back towards the panel.

2. Panel lighting apparatus as claimed in Claim 1 in which said reflection and diffusion

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Panel lighting apparatus This invention relates to panel lighting apparatus such as is used for shop facias, filling station forecourt canopies, and other applications, whether indoors or outdoors. Panel lighting apparatus employs a translucent front panel which may or may not carry indicia, and concealed illumination behind it. Commonly this illumination takes the form of fluorescent strip lighting, with the tubes closely spaced so as to obtain an effect of even illumination on the panel. In accordance with the invention, reflection and diffusion means are arranged in conjunction with the illumination means to return light directed rearwardly from the illumination means back towards the front panel. This increases the amount of light reaching the front panel, and helps to give more even illumination. One convenient form of reflection and diffusion means consists of diffraction foil, which is in effect a combination of a mirror and a diffuser in the form of a multiplicity of Fresnel lenses. A suitable diffraction foil is sold by Intra Plastics Limited in United Kingdom or by Coburn in United States, and consists of an embossed clear P.V.C. sheet with a coating of aluminium on the back. A very large proportion of the light reacing the diffraction foil is returned, but it is returned in a diffused form. By use of the diffraction foil it becomes possible to reduce the amount of illumination considerably. In a typical installation, only half the number of fluorescent tubes need be used. This can lead to economy in first cost and running cost, but it also makes it possible to arrange two systems of fluorescent tubes, one interleaved with the other, so that if a tube fails on the first system, the first system can be switched over to the second. An existing four-tube system can be rewired to make two two-strip systems, one acting as a spare. One preferred embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, which shows in sectional perspective part of an edge of a forecourt canopy with a panel lighting display fixed to it. Referring to the drawing, the canopy has a girder 1 extending around its edge: this is shown as a channel section with a web 2 facing outward. A light box designated generally 3 is secured to the girder 1 along the edge of the canopy. The light box 3 comprises a pair of similar aluminium extrusions 4, 5 at the top and bottom secured by pop rivets 6 to the upper and lower flanges 7, 8 of the girder 1. Double-sided foam adhesive strips 9 extend between the aluminium extrusions 4, 5 and the respective girder webs 7, 8 in way of the rivet 6.The extrusions 4, 5 each include a flat base 11, an intermediate upstanding flange 12, and a re-entrant front flange 1 3. The flanges 1 2 are secured to the girder web by pop rivets 1 4. Z-section aluminium extrusions 1 6 have flanges secured to the bases 11 by pop rivets 1 7. The re-entrant portions 1 8 of the front flanges 13, and the forward extending flange portions 1 9 of the Zsection extrusion 1 6 carry rubber beads 20 sealing against a front translucent facia panel 22. The beads 20 are in firm sealing engagement with the panel 22. A strip 23 along the top of the panel engages over the top front bead 20 and the panel to provide positive support for the bracket.Brackets 25 within the light box carry framework 26 spaced forwardly from the girder web 2 and the framework 26 carries four fluorescent tubes of which only one is shown diagrammatically at 27. The girder web 2 and preferably the inner surface of the upper and lower extrusions 4, 5 are covered with diffraction foil, adhesively secured and shown diagrammatically at 30: this foil is as above described. The diffraction foil has been found to increase surprisingly not only the level of illumination obtained at the front of the acrylic panel 22, but also the evenness of this illumination. Because of this it has been found sufficient to illuminate the panel with only two fluorescent tubes. While the arrangement could have been designed with only two such tubes, it will commonly be convenient to include four tubes as shown, with the first and third, and second and fourth, connected in two separate and independent circuits. Illumination can then be provided by one circuit, the other acting as a spare in case a tube of the first circuit should become defective. Thus, if it is decided not to economise in first cost by supplying only two tubes and their support fixtures, the advantage is obtained, besides saving fuel costs, in doubling the time between maintenance calls due to light failure. Existing panel lighting apparatus can be adapted to make use of the invention. It will be seen that the light box illustrated makes use of the canopy girder as a back. If desired, the light box could be self-contained, providing its own back. The foam strips illustrated at 9 provide a waterproof joint. CLAIMS

2. Panel lighting apparatus as claimed in Claim 1 in which said reflection and diffusion means comprises a diffraction foil.

3. Panel lighting apparatus as claimed in Claim 1 or 2 in which said illumination means comprises two groups of lamps connected in separate energising circuits.

4. Panel lighting apparatus as claimed in Claim 1 in which each group of lamps comprises two fluorescent tubes.

5. Panel lighting apparatus substantially as hereinbefore described with reference to the accompanying drawing.