GB2450092A

GB2450092A - Receptacle apparatus for a self-luminous light source

Info

Publication number: GB2450092A
Application number: GB0711147A
Authority: GB
Inventors: Frederick Douglas Williams
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-06-11
Filing date: 2007-06-11
Publication date: 2008-12-17
Also published as: GB0711147D0

Abstract

A receptacle apparatus 200 for a self-luminous light source comprises a retaining portion 300 and a base portion 302. The retaining portion 300 extends to the base portion 302 and are arranged to provide a diffusion volume between a first level of the retaining portion 300 and a second level of the base portion 302.

Description

I

RECEPTACLE APPARATUS

(0001] The present invention relates to a receptacle apparatus for a self-luminous light source of the type that, for example, serves to carry self-luminous light sources for disposal within a housing of a self-luminous sign.

(0002] In the field of self-luminous signage, it is known to employ tritium gas to manufacture so-called "self-luminous" light sources. In this respect, tritium gas-based light sources have been used for many years and across many industries to make safety signs, patterns and markers, as well as being used in instrument panels. Such self-luminous light sources have also found application in nautical environments, for example shipping, due to the ability of the self-luminous light sources to operate under-water without an external power supply or replacement of any internal power supply. The self-luminous light sources have also been employed in the aerospace industry as well as in difficult terrains, such as deserts, mountains, forests and on off-shore platforms.

3] Self-luminous tritium light sources are available in different configurations and sizes, for example cylindrical form with a circular cross-section, tubular form with a square or rectangular cross-section, torroidal form, or spherical form. For all such configurations, at least one surface, or part of a surface to be exposed in at least one direction, is employed as a light-emitting surface.

4] Chemically, tritium gas is an unstable isotope of hydrogen and emits electrons upon decay of the nucleus of the isotope, thus emitting low-energy 13 radiation. Tritium has an approximate half-life of 12.5 years and light sources comprising tritium gas have a useful lifespan of about 25 years.

[00051 13 radiation is emitted by the tntium gas and is known to excite certain phosphors, which are excited by the energy of the f3 radiation into a state that results in the emission of photons. Hence, purified tritium gas is sealed within a borosilicate glass capsule having its internal surface coated with a suitable phosphor to form the self-luminous light source. Typically, such self-luminous light sources are placed in troughs of a tray, the tray carrying the self-luminous light sources being encased in a mall black anodised aluminium housing or a high-impact plastic housing to preserve the structural integrity of the borosilicate glass capsule.

[00061 Indeed, examples of inefficient use of self-luminous light sources are disclosed in US patent no. US 4,383,382 and UK patent no. GB 1,030,951. In relation to GB 1,030,951, elongate self-luminous light sources are used in a segmented fashion to construct letters and numbers used behind a front panel in signage. For example, the capital letter E' is composed from one vertical light source and three, shorter, horizontal light sources. As an alternative, US 4,383,382 discloses the use of a front panel having opaque lettering formed therein and an array of parallel self-luminous light sources disposed behind the front panel and in front of reflectors of varying horizontal widths in order to provide illumination behind lettering of varying widths. However, provision of such arrays of parallel reflectors results in the presence of ridges between neighbouring reflectors. As a result of the parallel ridges, instead of the plurality of parallel self-luminous light sources contributing to a substantially even distribution of output light intensity from behind the front panel, an array of undesirable darkened lines is visible to the naked eye. The array of "strips", of lower intensity light output correspond to the locations of the ridges from where light is not being output. As mentioned above, this alternating pattern of varying light intensity levels is both visually unattractive but also reduces the effectiveness of any signage with which the array of reflectors is used.

7] Additionally, in harsh environmental conditions, such as those already mentioned above, it is desirable to provide the self-luminous light sources with greater protection from external influences. Additionally, it is also desirable to improve uniformly light intensity output achieved from the self-luminous light sources when installed within a housing [0008] According to a first aspect of the present invention, there is provided a receptacle apparatus for a self-luminous light source, the apparatus comprising: a base portion arranged to receive, when in use, a light source; and a light- transmissive layer disposed over the base portion.

9] The base portion may have an undulating surface. The undulating surface may define a trough for receiving the light source.

0] The undulating surface may define a plurality of peaks, the light-transmissive layer abutting the plurality of peaks.

1] The apparatus may further comprise a fixing arranged to hold the light-transmissive layer in abutment with the plurality of peaks.

2] The light-transmissive layer may be arranged to diffuse, when in use, light propagating therethrough.

3] According to a second aspect of the present invention, there is provided a receptacle apparatus for a self-luminous light source, the apparatus comprising: a retaining portion extending to a base portion, the base portion being arranged to receive, when in use, a light source; wherein the retaining portion and the base portion are arranged so as to provide a diffusion volume between a first level of the retaining portion and a second level of the base portion.

4] The base portion may have an undulating surface.

5] The base portion may define a trough for receiving the light source.

6] The separation of the first and second levels may be arranged to permit diffusion, when is use, of electromagnetic radiation emitted by the light source.

7] According to a second aspect of the present invention, there is provided a self-luminous sign unit comprising the receptacle apparatus as set forth above in accordance with the first and/or second aspect of the invention.

8] It is thus possible to provide a receptacle apparatus that provides improved protection to self-luminous light sources being carried. It is also possible to provide improved uniformity of light output by a self-luminous sign containing the self-luminous light sources.

9] At least one embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic diagram of a self-luminous sign unit; Figure 2 is a schematic plan view of a carrying apparatus constituting an embodiment of the invention; Figure 3 is a schematic side elevation of the carrying apparatus of Figure 2; and Figure 4 is a plan view of a fascia for use in the self-luminous sign unit of Figure 1.

0] Throughout the following description identical reference numerals will be used to identify like parts.

1] Referring to Figure 1, a self-luminous sign unit 100 typically comprises a housing 102 having side walls 104, a back plane (not shown) and a front panel 106 bearing an opaque textual message or piôtogram, for example the word "EXIT" 108, or a running man with an arrow pointing to a safe direction of escape.

2] Although not shown, the interior surfaces of the side walls 104 are provided with channels that serve as slots for receiving the back plane, a receptacle apparatus and the front panel 106. However, the skilled person will appreciate that other techniques for retaining the back plane, the receptacle apparatus and/or the front panel 106 can be employed. As such techniques are not directly relevant to an explanation of the present embodiment, the techniques for retaining the various parts of the self-luminous sign unit 100 will not be described in further detail herein.

3] Turning to Figures 2 and 3, the receptacle apparatus is, in this example a tray 200 having a peripheral retaining portion, for example a projecting edge, such as a brim 300. The receptacle apparatus 200 also has a based portion 302. In this example, the base portion 302 has an undulating surface defining a plurality of troughs 304 and a plurality of peaks 306 (depending upon orientation of the receptacle apparatus 200).

4] Self-luminous light sources 308 are respectively disposed within a number of the plurality of troughs 304.

5] The peripheral brim 300 is at a first level relative to a second level of the base portion 302. The receptacle apparatus 200 is formed so that a spacing exists between the first and second levels of height, h, the spacing being sufficient to define a diffusion volume in which diffusion of electromagnetic radiation emitted by the self-luminous light sources 308 can take place or at least commence.

6] In this example, the receptacle apparatus 200 is formed by an extrusion process for high-impact polystyrene. However, the skilled person will appreciate that any other suitable material and manufacture technique can be employed.

7] In another embodiment, the receptacle apparatus 200, irrespective of the provision of the diffusion volume described above, comprises a light-transmissive retention layer 310 that overlies the base portion 302. In this example, the retention layer 310 abuts the plurality of peaks 306 and serves to trap the self-luminous light sources within the respective troughs 304.

8] Abutment of the retention layer 310 with the base portion 302 can be maintained in a number of ways, for example through use of an adhesive or a number of screws 312 screwed through apertures (not shown) provided in the retention layer 310 and into a number of the plurality of peaks 306. The apertures provided in the retention layer 310 are therefore formed so as to be aligned with the appropriate peaks 306.

[00291 The retention layer 310 serves to protect the self-luminous light sources 308 and so, in this example, is formed from polycarbonate, though any other suitable resilient material can be employed.

0] During assembly, the brim 300 of the tray 200 is slotted into a channel (not shown) mentioned above and provided by the interior surfaces of the side walls 104. The front panel, or fascia, 106 is then also slotted into the channel over the tray 200.

Claims

Claims: 1. A receptacle apparatus for a self-luminous light source, the

apparatus comprising: a base portion arranged to receive, when in use, a light source; and a light-transmissive layer disposed over the base portion.
2. An apparatus as claimed in Claim 1, wherein the base portion has an undulating surface.
3. An apparatus as claimed in Claim 2, wherein the undulating surface defines a trough for receiving the light source.
4. An apparatus as claimed in Claim 2 or Claim 3, wherein the undulating surface defines a plurality of peaks, the light-transmissive layer abutting the plurality of peaks.
5. An apparatus as claimed in Claim 4, further comprising a fixing arranged to hold the light-transmissive layer in abutment with the plurality of peaks.
6. An apparatus as claimed in any one of the preceding claims, wherein the light-transmissive layer is arranged to diffuse, when in use, light propagating thereth rough.
7. A receptacle apparatus for a self-luminous light source, the apparatus comprising: a retaining portion extending to a base portion, the base portion being arranged to receive, when in use, a light source; wherein the retaining portion and the base portion are arranged so as to provide a diffusion volume between a first level of the retaining portion and a second level of the base portion.
8. An apparatus as claimed in Claim 7, wherein the base portion has an undulating surface.
9. An apparatus as claimed in Claim 7 or Claim 8, wherein the base portion defines a trough for receiving the light source.
10. An apparatus as claimed in Claims 7, 8 or 9, wherein the separation of the first and second levels is arranged to permit diffusion, when is use, of -electromagnetic radiation emitted by the light source.
11. A self-luminous sign unit comprising the receptacle apparatus as claimed in any one of the preceding claims.
12. A receptacle apparatus substantially as hereinbefore described with reference to Figures 1 to 4.