GB2176043A - Luminous advertising signs using optic fibres and presenting lights with fixed and/or variable colours - Google Patents

Abstract

An advertising sign comprises a bundle of optic fibres 4 the ends of which are respectively embedded in a luminous panel 5 for displaying advertisements and directed towards a light source 6 having a reflector 1. Between the ends of the optic fibres 4 directed towards the light source 6 and the light source 6 itself is a coloured filter 2, here in the form of disc made up of a number of sections of different colours and rotatable by means of an electric motor 3. The optic fibres 4 conduct light given off by the light source, and coloured by the filter 2, to the surface of the panel 5. <IMAGE>

Description

SPECIFICATION Luminous advertising signs using optic fibres and presenting lights with fixed and/or variable colours This invention concerns luminous advertising signs using optic fibres.

The advertising signs in accordance with the present invention are characterised in that they use plastics optic fibres, present lights with fixed and/ or variable colours, and in that they may be used in the open air, inside buildings or under water, may have any size or form, from small advertising used for instance in show cases, miniature signs in small show cases, to big signs rigged up on roofs or platforms, and including medium sized signs in hanging supports or show windows.

The advertising signs in accordance with the present invention form, through their characteristics, a new concept within the field of advertising signs, which satisfies the modern needs of a low energy consumption and reduced maintenance costs, these being characteristics which give them a large range of applications within the ambit of luminous advertising signs.

Advertising signs employing optic fibres include basically: one or more light sources; one or more coloured filters; one or more driving motors for the coloured filters; one or more bundles of plastics optic fibres; and an advertising panel having symbols to be illuminated.

The invention will be described further, by way of example, with reference to the accompanying drawings in which: Figure 1 is a lateral view of the assembly of principal components of an advertising sign comprising optic fibres; Figure 2 is a perspective view of a different assembly of the components of an advertising sign comprising optic fibres; Figure 3 is a perspective view of a coloured filter in the form of a cylindrical drum, rotationally driven by an electric motor and having inside a light source and the corresponding reflector, and outside the receiving end of the bundle of optic fibres; Figure 4 is a longitudinal cross section through an optic fibre showing its composition and the way in which the light is propagated by means of total internal reflection;; Figure 5 is a perspective view of a rough plate which may be heated, and of the end of the fibre to be treated by the same, in order to obtain an adequate diffusion of the light in its emitting end; Figure 6 is a lateral view of the end of the optic fibre through which the light goes out, after said end has been enlarged by treatment with the heated rough plate shown in Figure 5; Figure 7 is a cross section showing a way of obtaining the diffusion of the light by means of the use of a front plate consisting in transparent or translucid acrylic material; Figure 8 is a cross section showing the optic fibres already fixed to the rear face of the base plate by means of an adhesive material; Figure 9 is a perspective view showing a way of obtaining the receiving end of a bundle of optic fibres disposed parallel one to another;; Figure 10 is a perspective view showing the light receiving end of a bundle of optic fibres compressed by means of a screw clip; Figure ii is a perspective view showing the use to two coloured filters in the form of rotating discs in order to obtain more complex mixtures of colours; Figure 12 is a perspective view showing the synchronous driving of two rotating coloured filters by means of a chain connecting two toothed gear wheels mounted on the axis of each filter; and Figure 13 is a cross sectional view of a tube applied and fixed with adhesive material on the two parts of an optic fibre in order to join them after a fracture.

Referring firstly to Figures 1 and 2, in the preferred advertising sign light emitted by the light source placed inside a reflector 1 goes through coloured filter 2 rotated by an electromotor 3 with speed reductor and enters into the receiving end of the optic fibres 4 which transmit the light to a base panel or advertising sign 5.

The light source may consist of one more lamps 6 of high power, equipped with corresponding reflector 1. The coloured filter consists, in its simplest form, of a glass disc 2. It is also possible to use coloured filters in the form of a cylindrical drum 7 (Figure 3) when the range of colour variation and the available space make this necessary.

The optic fibres 4 may be of various diameters and chosen in view, necessarily, of the type of advertising emblem and the size of the advertising sign. The latter may have a flat or a curved surface, and also the possibility exists of forming emblems merely by means of the disposition of the optic fibres.

When the optic fibres 4 in the advertising sign 5 have a disposition similar to that existing in the light source, the alteration introduced by the coloured filter 2 is enlarged in the visual panel, which constitutes a new characteristic of advertising signs in accordance with the present invention.

In luminous advertising signs having optic fibres, the changes in colour or colour pattern are obtained in a rather economic way in comparison with known types of advertising signs, since it is only necessary to replace the coloured disc or the motor-reductor assembly, this being easy to carry out.

The use of high powered light sources allows a significant reduction in the consumption of energy in comparison with the advertising signs using incandescent or fluorescent lamps, and the luminosity produced by the former is easily controlled by the simple replacement of one or more lamps.

The small cost of conservation necessary for the advertising signs in accordance with the present invention are particularly the result of the fact that the same are using a much smaller number of light sources than that necessary for conventional advertising signs, because of which the failures occurring in the former are also considerably less, and the simplicity of the replacement of a lamp and the reduced frequency of these replacements limit the possible use of scaffolding and the execution of other dangerous and costly operations.

The simple and resistant nature of the structure of the optic fibre makes the occurrence of a fracture of the same very rare, with the consequent interruptions of the illumination of the advertising signs.

As already mentioned hereinbefore, the luminous advertising signs using optic fibres may have an ample variety of forms and dimensions.

The light source and the advertising sign 5 are separated, thus permitting the application of various constructive compositions.

Since plastics optic fibre may be easily manipulated and worked with, the manufacture of a big variety of luminous moulds and forms is carried out without difficulties and therefore this type of luminous advertising signs provides an advantageous solution. On the other hand, optic fibre allows due to its elastic properties, the excellent transmission of coloured light and does not cause short-circuits or sparks, so that various types of luminous advertising signs, including under-water types, may be used in aquariums, swimming pools and so on.

As shown in Figure 4, an optic fibre comprises an interior 8 consisting of polymethyl methacrylate, which is transparent and has a high refractive index, covered by a thin layer 9 of special transparent material with a low refractive index, because of which the light, received in one of its ends is propagated by means of successive total internal reflection against the interface of the two components, and is emitted from the fibre's other end with only a slight attenuation.

When assembling the various components of a luminous advertising sign, it is sometimes necessary to use adhesive materials. In order not to cause any reduction in the transmission of light by the optic fibres or, in extreme cases, danification or destruction of the same, it is necessary to avoid.

completely the use of products such as benzene, ethyl acetate, petrol etc.

In view of the fact that a radius of curvature smaller than 10 times the diameter of the optic fibre could cause the transmission of light through the side wall of the optic fibre, and that a small radius of curvature, maintained during longer periods, may cause an internal stress in the material of the fibre which might cause its fracture, it is advisable to use only radii of curvature bigger than 100 times the diameter of the fibre. In any case, if the mounting conditions should require the application of a narrow radius of curvature, the internal stress in the optic fibre may be relieved by means of a heat treatment.

If there should be any reason to be concerned about the inflammability of the optic fibre, which is equal to that of acrylic resins, the fibres will have to be clad or covered with heat resisting materials, such as aluminium sheet and polyamide tape.

For realising luminous advertising signs in accordance with the present invention, it is necessary to elaborate previously a plan and a design in order to make complete use of their characteristics.

The fundamental points to be considered, particularly in the case of advertising signs of large dimensions, are the following: a design considering the relative positions of the sign and of the observer; the choice of the luminous system to be adopted; the choice of the diameter of the optic fibre.

The determination of the size of the advertising sign is made in accordance with the distance between the sign and the observers, and the spacing of the fibres in the luminous panel, which is also called a base plate, should be such that it allows to see individually, the light which is emitted.

The light emitted by the optic fibre has a distribution of intensity between +20 and -20", which makes it advisable to adopt, for the mounting of the optic fibres in the luminous panel, an inclination of about 20 .

The lighting systems to be adopted depend greatly, as is understandable, on the disposition of the optic fibres in each case, both in the luminous panel and in the light source, on the types of filter to be used, on the desired type of advertising emblem, on the size of the base panel, on its distance to the observer, on the size of the letters, etc. In short, the variables are so numerous that the solutions to be adopted must be studied in each separate case.

In view of the fact that the dimensions of the advertising signs, as already mentioned, and consequently the size of the base panel, have a direct relationship to the distance to the observer, it can also be said that the type and the power of the light sources used, i.e. of-the lamps, are also subject to the same relationship, high power lamps having a longer useful life than that of low power lamps.

The luminous panel or sign 5, where the emitting ends of the optic fibres are situated, consists usually of an acrylic sheet. Other materials may also be used, such as metal plates with double walls.

In the conservation of said sign 5, the application of organic solvents should be avoided, in order not to cause danifications or fractures of the optic fibres, as already mentioned.

The optic fibres 4, are in their primary condition, characterised in that they have a light emitting angle of 60 , because of which the luminous sign 5 without other measures, would be highly directional. In order to avoid these directional characteristics it is necessary to treat the light emitting end of the optic fibre by means of one of the following processes: rubbing it with a sheet of emery-paper; subjecting it to the action of sand-blasting; covering it with a fine layer of light diffusing material; covering it with fine transparent particles such as glass pearls; roughening it by means of contact with a heated plate 10 with rough surface (Figure 5).

The choice of the treatment of the light emitting end of the optic fibre, in order to cause a convenient diffusion of the emitted light, depends on the type of advertising sign in which the fibres 11 are to be used. By way of example it is to be mentioned that the treatment with a sheet of emery-paper is suitable for luminous advertising signs of small dimensions, and that the treatment with a roughened hot plate 10 is suitable for advertising signs with medium and large dimensions.

Another important treatment of the light emitting end of the optic fibre consists in its deformation under pressure (Figure 6) carried out together with the roughening treatment by means of the roughened hot plate 10.

In order to obtain the diffusive effect of the emitted light, it is also possible to use a transparent or translucent sheet of acrylic material 12 (Figure 7) as a front plate without necessity of applying any of the aforementioned treatments.

The fixing of optic fibres 13 in base plate 14 (Figure 8) is carried out threading them through holes drilled in the plate 14, and fixing them by means of adhesive material 15 on the back of the base plate 14. After that a pressure plate (not-shown) is placed behind the base plate 14.

The disposition and fixing of the receiving ends of the optic fibres, near the source of light, should be carried out in such a way that the fibres are placed in a parallel relationship in order to avoid variations of luminosity caused by differences in the angle of entry in the receiving end. For this purpose may be used a device as shown in Figure 9, wherein the optic fibres 16 positioned in a clamping support 17.

In conjunction with small advertising signs, the bundle of optic fibres 18 (Figure 10) may sometimes be fixed by means of a screw clip 19.

When it is necessary to cut the optic fibres, this operation can be carried out by means of cheated knife, an emery cutting disc or a finely dented circular saw. In this last mentioned case, the formation of the cut will have to be cooled by means of a cooling liquid.

The circuit saw above mentioned may possibly be replaced by a wood saw or metal saw with fine dents.

The bundles of fibres after having been cut are submitted to a polishing operation which may be carried out by means of vibrating machines equipped with a sheet of ernery paper, or with a soft cloth drenched in an acrylic polishing agent, this being an operation which has for its purpose to reduce significantly the losses in luminosity due to the dispersion of the light in the end of the fibres.

The light source may consist, in most cases, of a lamp, a coloured filter and a driving system, for the rotation of the filter, comprising a motor and speed reductor.

In case of the use of big and powerful lamps, it is necessary to include in the assembly a heat absorbing filter, and its corresponding cooling equipment.

It is not judged necessary to describe here the range of lamps which may be used as light sources, and reference will be made to the aspects which should be considered in relation to the characteristics the coloured filters should have.

The coloured filters, normally in the form of a disc, may consist of a sheet of plastics material such as polycarbonate or poly-methylacrylate or of a glass disc.

The colouring of the filter may be achieved, for example, by means of stamping, or by manual application of transparent paints of various colours, or by assembling various layers of coloured transparent sheet.

A filter system consisting of only one disc with transparent coloured sectors has the inconvenience that the changes of colour are limited, but with the use of a combination of two or more coloured discs (Figure 11) it is possible to obtain more complicated colour schemes.

As already mentioned and shown in Figure 3, the coloured filters may also have the form of a cylindrical drum.

In order to increase the direct incidence of the light into the optic fibres, it is necessary to use a reflector 1 (Figure 1) near the lamp. If the selected reflector is of the type which focusses the light, the region of focussing will evidently develop heat, which will have to be counteracted by means of conventional processes, in order to avoid danification of the optic fibres.

When the light source consists of an incandescent lamp with a power of 20 W or more, it will be necessary to install a filter A (Figure 1) which absorbs the heat. With a lamp powered with less than 20 W, it is sufficient to install a glass sheet which absorbs the infra-red rays and which may be a sheet of ordinary window glass. In the case of high powered lamps, it will be necessary to use a heat-absorbing filter with good characteristics, together with a forced cooling device.

In the case of large luminous advertising signs, the show panel is normally divided into two or more sections, and lighted by various light sources.

The distribution of the light emitted by these light sources in direction of the corresponding coloured filters has to be synchronised in order to obtain a uniform colour variation over the entire surface of the advertising sign. In order to obtain a synchronous movement of all the coloured filters 20 (Figure 12), the driving axles of these filters are normally interconnected mechanically by means of a chain 21 and sprocket wheels, or by a cable, or by gear wheels, or by means of an electronic synchronising device, this last mentioned solution offering the advantage of not limiting the location of the light sources.

Evidently, the safety measures required for the construction and the conservation of any type of luminous advertising sign will also have to be observed for the advertising signs in accordance with the present invention.

However, it is easily understandable after all that has been said hereinbefore about the characteris tics of luminous advertising signs employing optic fibres that the latter are much safer than known advertising signs because they do not need the application of high voltage, do not require a large quantity of electric wires and connectors and the few which are used are located in a limited zone and are easy to protect, contrary to what is found in luminous advertising signs using electric lamps or neon tubes in the advertising panel.

Though the optic fibres used have a good mechanical resistance, it is quite possible that as a consequence of any eventual bad treatment, they may break or have their light transmission property diminished. In such a situation, the solution to be adopted is simple and consists in connecting the two parts 22 (Figure 13) of the broken fibre by a tube 23 which maintains them in the correct position and in which the ends of said two parts are fixed by means of an adequate adhesive material 24.

In short, the luminous advertising signs in accordance with the present invention are completely reliable, not offering the working irregularities which are found in conventional advertising signs.

They allow a variation in colour with only one optical conducting element, they transmit truly, without darkened points, the publicit message. The luminous advertising signs of the invention may be used under water without-any risk; they have a low energy consumption since the electric power installed is rather low; the cost of their maintenance is very low; the probability of occurrence of accidents in their electrics is practically zero, and their general characteristics give them a wide range of applications within the ambit of luminous advertising signs.

it may be said that luminous advertising signs employing optic fibres constitute therefore an undisputable progress within the corresponding technical field.

Claims (10)

1. A luminous advertising sign comprising optic fibres and presenting lights with fixed and/or varia ble colours, characterised in that said sign further comprises a frontal protection panel, a visual panel showing the design and/or letters of the advertise ment and through which the optic fibres are extendable in order to conduct light received in their receiving ends placed near a lamp provided -with a reflector towards their other ends which emits the light towards observers.

2. A luminous advertising sign as claimed in claim 1, characterised in that between the source of light and the bundle of optic fibres is a transpar ent coloured filter of various colours and which can be driven rotationally by an electromotor with a speed reductor to allow a change in colour of the light emitted by the end of each one of the optic fibres, fitted through the visual panel in the direction of observers.

3. A luminous advertising sign as claimed in claims 1 or 2, characterised in that in the case of large size signs, there are provided one more light sources of high energy, these high powered lights having in front of them a heat absorbing filter which is provided with a device for forced ventilation when a natural ventilation system should be considered as insufficient.

4. A luminous advertising sign as claimed in any preceding claim, characterised in th-at the diameter of the optic fibres to be used depends on the type of design and on the dimensions of the visual panel and on the distance between the latter and observers, the fibres with the smallest.diameters being used in advertising signs with small sizes and situated near observers.

5. A luminous advertising sign as claimed in any preceding claim, characterised in that they may present a big variety of luminous effects, they may have any size and form and may also be used under water in aquariums and swimming pools, etc., without any danger since the under-water part of the advertising sign is completely separated, by means of the bundle of optic fibres, from the part equipped with the electric installation.

6. A luminous advertising sign as claimed in any preceding claim, characterised in that all their constructive components may be applied in a wide range of different ways in conformity with what is judged necessary for the specific case of the advertising sign and of the limitations of space or otherwise which sometimes should be applied.

7. A luminous advertising sign as claimed in any preceding claim, characterised in that the end face of the optic fibres, emitting the light transmitted by the latter, is in need of an adequate treatment for the purpose of avoiding the inconvenience of the directional property of the light and permitting a convenient diffusion of the light, this treatment for instance consisting, in the case of large advertising signs, in roughening and enlarging the top of the fibre, by means of pressing this top against a roughened and heated plate.

8. A luminous advertising sign as claimed in any preceding claim, characterised in that the reduced number of light sources and electric wires used and the sheltered and isolated form which may be given them as well as to the driving motors for the rotation of the coloured filters allow functioning practically without interruptions, an extraordinarely economic maintenance without the necessity of using frequantly dangerous working means, such as stairs and scaffolds, and a very reduced energy consumption.

9. A luminous advertising sign as claimed in any preceding claim, characterised in that the efficient way in which the optic fibres transmit the light, which is coloured and varied in accordance with the moving filters, allows, in a new and simple way, a practical result which is truly surprising.

10. A luminous advertising sign substantially as hereinbefore described with reference to and as illustrated in Figure 1 and Figures 3 to 13, or in Figures 2 to 13 of the accompanying drawings.