GB2235760A

GB2235760A - A lighting apparatus

Info

Publication number: GB2235760A
Application number: GB8918300A
Authority: GB
Inventors: Kenneth Barry Shorland
Original assignee: Starlowe Lighting & Design Lim
Current assignee: Starlowe Lighting & Design Lim
Priority date: 1989-08-10
Filing date: 1989-08-10
Publication date: 1991-03-13
Anticipated expiration: 2009-08-10
Also published as: GB8918300D0; GB2235760B

Abstract

A lighting apparatus comprising a casing, a reflector means disposed within the said casing and at least one fluorescent light element mounted relative to said reflector wherein at least a portion of said casing is adapted to form a lens system. Preferably an upper part of the casing has longitudinal ribs formed therein which act as a lens system to efficiently direct the light from the low energy fluorescent sources into the area to be illuminated.

Description

LIGHTING APPARATUS This invention relates to lighting apparatus.

Where it is required to light a relatively large area, in order to achieve adequate illumination thereof, it is usual to use multiple, powerful lamps which are mounted above the area to be lit. Conventionally the lamps used for this purpose incorporate tungsten filament bulbs as the light source, which bulbs consume a relatively large amount of electrical power.

Thus is can be seen that if the area to be illuminated is particularly large, a large number of such lamps would be required and thus the consumption of electrical power can be unacceptably high.

Low energy light sources are known, however it has not been possible thus far to efficiently-use the light emitted therefrom in order to obtain adequate levels of illumination.

It is an object of the present invention to provide a lighting apparatus which overcomes or at least minimises the abovementioned problems.

According to the present invention therefore there is provided lighting apparatus comprising a casing, reflector means disposed within said casing, at least one fluorescent light element - mounted relative to said reflector, wherein at least an upper surface of said casing is adapted to form a lens system whereby light emission from said at least one element can be efficiently directed from said casing.

With this arrangement is is possible to provide lighting apparatus which can illuminate an area in a cheap and effective manner.

Preferably said adaptation of the upper surface of the casing takes the form of longitudinal ribs defining said lens system. The ribs may extend over a major part of the upper surface and may be disposed side by side with no spaces therebetween.

Said casing may comprise two parts, a lower and a cover part. Preferably the lower part is formed from opaque material and the cover part from a transparent material. In this case said ribs are provided on said cover part.

Said cover part may be provided with two upstanding edge structures which may extend around the whole or a part of the periphery thereof. Said lower part may have a convex back surface thereto and may furthermore have a projecting sealing lip extending around the external periphery thereof which is adapted to abut an outer of said edge structures of the cover part, when joined, thereby to provide a seal between said two parts.

The two parts can be arranged to be joined together in any suitable manner for example with screws, pins or the like or alternatively the two parts may be arranged to be a snap fit.

The two casing parts may be formed from a plastics material, for example polycarbonate.

The reflector may be formed from a metallic material and may be shaped to define a central stepped portion having a central step thereto, and projecting wings at each end thereof. The reflector may be mounted in said lower part and two light elements may be disposed thereon, one on each side of the central step.

The at least one fluorescent light element may comprise a low energy fluorescent tube.

The invention will now be described further by way of example only and with reference to the accompanying drawings of which: Figure 1 shows a sectional side view of a part of one form of casing according to the invention; Figure 2 shows a plan view of a further part of the casing of Figure 1; and Figure 3 shows an end view, to a smaller scale, of one form of reflector according to the invention.

Referring now to Figures 1 and 2, there are shown two parts 1, 2 which are adapted to fit together to form the casing for the apparatus.

Figure 1 shows a lower casing part 1 which is of generally triangular form. The part 1 is formed from moulded plastics, for example polycarbonate and comprises an open topped receptacle having four side walls (3, 4, not shown) linked by a base wall 5. The base wall 5 comprises two sections 6, 7 that are inclined relative to each other thereby defining a convex back surface to the casing part 1. A continuous projecting sealing lip 8 of triangular form extends along an upper part of each side wall (3, 4, not shown), adjacent the open top 9 of the receptacle for a purpose to be described hereinafter.

Four cover attachment members 10 of generally cylindrical form are disposed in each corner of the casing part 1. Each cover attachment member 10 has a central bore (not shown) which is screw-threaded on the interior and is used to fix the upper or cover casing part 2 in position in a manner to be described hereinafter. Multiple reflector attachment members 11 are also provided disposed adjacent the side walls (not shown). The reflector attachments 11 are of similar configuration to the cover attachments 10 and are used to fix the reflector 12 in position in the casing 1 also in a manner to be described hereinafter.

An aperture (not shown) is provided in the base wall 5 of the lower part 1 for entry of a power supply cable.

A swivel joint (not shown) is provided attaching the cable to the lower part 1 whereby the part 1 can be rotated by 900 in two directions about the cable.

Figure 2 shows the upper or cover casing part 2 which is of generally square configuration. Two spaced upstanding edge structures 13, 14 extend around the periphery of the cover part 2, an outer one 13 of which projects from the cover 2 by a greater distance than an inner one 14 thereof.

Four cover attachment members 15 are disposed at each corner of the inner edge structure 14 and are adapted to cooperate with the corresponding attachment members 10 of the lower casing part 1. Bores 16 extend through the attachment members 15 and open out onto a top surface of the cover part 2.

Multiple curved rib structures 17 are provided over a major part of the cover 2, which ribs act to scatter the light passing therethrough uniformly in all directions. Thus the ribs 17 act as what is commonly known as a diffuser.

Figure 3 shows a reflector 12 for use within the casing. The reflector i2 comprises a shaped sheet of highly polished metallic material having a stepped central portion 18 and projecting side portions 19 at each end thereof having a plurality of bores (not shown) provided therein. The stepped central portion 18 has mountings for two low power 9w fluorescent tubes 20 on both sides of the step 18.

Beneath the central step 18 are mounted the usual components associated with operation of the fluorescent tubes 20, for example the choke and transformer etc.

In use the apparatus is assembled by firstly mounting the reflector 12, with the fluorescent tubes 20 thereon, in the lower casing part 1. This is achieved by aligning the bores (not shown) in the projecting side portions 19 with the bores (not shown) in the reflector attachments 11 in the lower casing part 1, and then securing the reflector 12 in position by use of screws or pins or the like. With the reflector 12 in position the fluorescent tube light sources 20 face the open top 9 of the casing part 1.

The cover part 2 is then fitted onto the lower casing part 1 by positioning the upper part of the side walls (3, 4, not shown) of the lower casing part 1 between the upstanding edge structures 13, 14 and then pushing the cover part 2 and lower casing part 1 together until the outer edge structure 13 is in abutment with the sealing lip 8. Thus an efficient seal is created which prevents any escape of light from the casing with the exception of through the top surface of the cover part 2.

Thus formed the apparatus acts to use light from a low energy light source 20 in an efficient manner. The configuration of the reflector 12 and the provision of the specific configuration of ribs 17 forming the diffuser enable light to be uniformly directed over the area to be lit, and losses of light through the casing are minimised.

With the arrangement described above it is possible to use a low energy light source in a highly efficient manner thereby to allow illumination of large areas therewith with an accompanying energy and therefore cost saving.

It is of course to be understood that the invention is not intended to be restricted to the details of the above embodiment which are described by way of example only.

Claims

1. Lighting apparatus comprising a casing, reflector means disposed within said casing, at least one fluorescent light element mounted relative to said reflector, wherein at least an upper surface of said casing is adapted to form a lens system whereby light emission from said at least one element can be efficiently directed from said casing.

2. Lighting apparatus according to claim 1 wherein said adaptation of the upper surface of the casing comprises longitudinal ribs which define said lens system.

3. Lighting apparatus according to claim 2 wherein said ribs extend over a major part of the upper surface of the casing.

4. Lighting apparatus according to claim 2 or claim 3 wherein said ribs are disposed side by side with no spaces therebetween.

5. Lighting apparatus according to any one of claims 1 to 4 wherein said casing comprises two parts, a lower and a cover part.

6. Lighting apparatus according to claim 5 wherein said lower part is formed from an opaque material and the cover part is formed from a transparent material.

7. Lighting apparatus according to claim 6 when dependent on claim 2 wherein said ribs are provided on said cover part.

8. Lighting apparatus according to any one of claims 5 to 7 wherein said cover part is provided with two upstanding edge structures.

9. Lighting apparatus according to claim 8 wherein said edge structures extend around the whole of the periphery of said cover part.

10. Lighting apparatus according to any one of claims 5 to 9 wherein said lower part has a convex back surface thereto.

11. Lighting apparatus according to any one of claims 8 to 10 wherein said lower part has a projecting sealing lip extending around an external periphery thereof which is adapted to abut an outer of said edge structures of said cover part, when joined, thereby to provide a seal between said two parts.

12. Lighting apparatus according to any one of claims 5 to 11 wherein said cover and lower parts are joined together by way of screws.

13. Lighting apparatus according to any one of claims 5 to 11 wherein said cover and lower parts are joined together by way of a snap fit.

14. Lighting apparatus according to any one of claims 5 to 11 wherein said cover and lower parts are formed from a plastics material.

15. Lighting apparatus according to claim 14 wherein said plastics material comprises polycarbonate.

16. Lighting apparatus according to any one of claims 1 to 15 wherein said reflector is formed from a metallic material.

17. Lighting apparatus according to any one of claims 1 to 16 wherein said reflector is shaped to define a central stepped portion having a central step thereto, and projecting wings at each end thereof.

18. Lighting apparatus according to any one of claims 5 to 17 wherein said reflector is mounted in said lower part.

19. Lighting apparatus according to claim 17 or claim 18 wherein two light elements are disposed on said reflector, one on each side of the central step.

20. Lighting apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying Figures.