EP1526793A1

EP1526793A1 - A display system

Info

Publication number: EP1526793A1
Application number: EP03740840A
Authority: EP
Inventors: Allan The Technology Partnership plc CARMICHAEL; Neil The Technology Partnership GRIFFIN
Original assignee: Technology Partnership PLC
Current assignee: Technology Partnership PLC
Priority date: 2002-07-24
Filing date: 2003-07-24
Publication date: 2005-05-04
Also published as: GB0217192D0; AU2003281492A1; WO2004008920A1

Abstract

A display system comprises a variable, illuminating light source. Packaging contains, in use, an object to be displayed, the packaging comprising an optical filter, and a polariser is provided. In use illuminating light from the light source passes through the optical filter to generate a lighting effect which is visible to a viewer.

Description

A DISPLAY SYSTEM

The present invention relates to display systems for displaying products to potential selectors or purchasers. Packaging for products can serve a number of purposes, including protection from physical damage or contamination, tamper evidence, anti-counterfeiting, theft protection, display of information and product promotion. The purpose of product promotion is to strengthen the product brand by making a strong impact, draw the attention of a potential selector or purchaser, and persuade the potential selector or purchaser to choose the promoted product in preference to other products.

Standard systems utilise colour and shape of external packaging of a product to enhance the product in the mind of the selectors/purchasers of the product. Lighting may be used to good effect to improve the visibility and increase the impact of the aforementioned packaging techniques. Consumers are becoming ever more sophisticated in their perception and expectations. Plain packaging, whilst serving the utilitarian function, may fail to perform the alternative function of drawing the attention of the consumer.

Some techniques have been employed to create a more dynamic visual effect such as the use of holograms or lenticular films that change appearance as the viewing angle changes, or thermochromic materials that change colour in response to a change in temperature, for example, when the product is touched. These approaches sufferfrom the limitation that the effect occurs in response to some action by the potential selector or purchaser and hence they do not draw the attention as strongly as an effect that occurs independently of the potential selector or purchaser. Existing approaches to achieve this type of independent dynamic image require the incorporation of active components such as power sources and light sources, into the packaging. Although application of new technologies, such as organic light emitting diodes, printable electronics and printable batteries allow the size and cost of these solutions to be reduced, for the foreseeable future, the cost of these components will be too high for incorporation into low value consumer items, such as food or cleaning products. The present invention overcomes this cost barrier.

The present invention seeks to improve the prior art by introducing effects that appeal to the consumer and draw their interest to the product being displayed.

According to the present invention there is provided a display system comprising: a variable, illuminating light source; packaging for containing, in use, an object to be displayed, the packaging comprising an optical filter; and a polariser, wherein, in use, illuminating light from the light source passes through the optical filter to generate a lighting effect which is visible to a viewer. The variable illuminating light source may be provided by an ordinary light source in combination with the polariser. In such a case the polariser may be rotated in the path of light between the light source and the packaging. The packaging may comprise at least one layer of a birefringent material in addition to a layer of polarising material.

The optical filter may introduce wavelength dependence to the lighting effect produced.

According to the present invention there is further provided a display system comprising: a variable, illuminating light source; and packaging for containing, in use, an object to be displayed, the packaging comprising an optical filter, wherein, in use, illuminating light from the light source is varied in spectrum such that, in combination with the packaging, a metameric effect is produced which is visible to a viewer.

According to the present invention there is further provided a display system comprising: an illuminating light source; and packaging for containing, in use, an object to be displayed, the packaging comprising an optical guide, wherein the surface of the guide has light emitting regions formed therein to generate a lighting effect which is visible to a viewer.

The present invention provides a new approach to providing a dynamic visual effect within product packaging wherein the packaging contains only low cost components. High cost components, such as power source, light emission and light modulation control components may be contained in a separate reusable illuminator. Therefore by incurring a one-off expense for the illuminator it is possible to create a strong visual impact from packaging that is cheap to manufacture. Depending on the particular embodiment of the display system, the illuminator may project light onto the packaging from a remote position or it may inject light into the packaging from a position in close proximity.

The principles described herein may be modified so that the means for making changing illumination visible may be an integral part of the product, such as for example an optically active edible dye in a food product, or the means may be incorporated into a sign to produce a similar visual effect.

Examples of the present invention will now be described with reference to the accompanying drawings, in which: Figure 1 illustrates an example of the invention, in which an optical waveguide is incorporated into packaging material;

Figure 2 illustrates how, in the invention, a metameric effect is generated in combination with a colour varying light source;

Figure 3 illustrates how a combination of filters may be used in the present invention;

Figure 4 and Figure 5 show display systems according to the invention in which a polariser is used;

Figure 6 illustrates a display system of the present invention utilising a liquid crystal display; and Figure 7 shows a further detailed example of the invention.

The present invention centres around the packaging and presentation of a product 1 to the potential selector 5. Packaging is provided in the form of an optical waveguide 4 or similar optical system such that when the product's packaging is illuminated, in use, an interesting lighting effect is achieved that enhances the appeal to the viewer 5. In one example the packaging is designed such that the light is transferred to patterned areas of the packaging whence it is directed towards the viewer so that from the viewer's perspective the packaging appears to contain a light source.

In one example of the present invention, as illustrated in Figure 1 , the product 1 may be placed on a light source 2 (which may be focussed using lens 3). The light is transmitted through the packaging material, in this case using a waveguide 4, to selected areas 4a of the packaging where the light is redirected or scattered out of the packaging and towards the viewer 5. The selected areas 4a have been treated to scatter the light either by selectively applying a coating material to the packaging material, selectively incorporating scattering material or grating pattern within the waveguide, selectively providing a texture or grating pattern to the surface of the waveguide or shaping the waveguide such that tight angled bends, cuts or ridges are formed through which light may escape. The light may also escape by natural light leakage from a leaking waveguide. The selected areas 4a may take the form of lettering or patterning. By additionally varying the colour, brightness and/or timing of the light source 2 (not shown in Figure 1) the visual effect which is presented to the viewer 5 will be varied and thus be more attractive/appealing and provide a strongerfimpact than a standard printed effect. It may be that a textual message or design appears to be back lit, change colour or even that such images may appear and then disappear.

The waveguide 4 may be formed during the standard processes involved in producing product packaging such as injection moulding, stamping or embossing.

Alternatively the waveguide 4 may be manufactured separately and subsequently bonded to the packaging after this has been formed, for example, a sheet being wrapped around a bottle.

The design of the waveguide 4 can introduce a wavelength dependency of the light emission features of the display system. Diffraction gratings, wavelength dependent birefringent layers and polarisers , tapered and tightly curved waveguides expel different wavelengths, whilst doped waveguides absorb different wavelengths. Colour dependent angle of entrance into a waveguide may be introduced by selecting radii/curvature of bends or angles of grating, thus allowing colour selective light leakage. Light can be coupled into the waveguide by directing light into the end surface of the waveguide or via a grating or a scattering or a reflecting area patterned onto a coupling region on the front or back surface of the waveguide. In one example, the packaging also incorporates multiple waveguides which may have separate light sources to allow the appearance of different patterned regions 4a to be controlled independently. Figures 2 to 7 illustrate a general class of display system according to the present invention wherein the illuminator projects light onto the displayed product from a remote location. The light from the illuminator may be varied and this light variation may be undetectable when viewed directly or when viewed via an object that has not been specially prepared. The packaging on the product to be displayed contains a means by which the light variation becomes visually detectable. This means may take the form of lettering or patterning which therefore appears to change in appearance as the illumination is varied.

Two examples of this type of display system will now be described in which the first utilises the effect of metamerism and the second employs a polarised light source combined with polarising and birefringent packaging materials.

In Figure 2, the facility to vary the spectral content of the incident light is incorporated into the light source 2', in addition a colour filter 6 may be provided in combination with the light source 2'. This allows the phenomenon of metamerism to be utilised in the display of the product 1 to the viewer 5. Such a feature allows a message or image 7 on the packaging to effectively change in appearance to the observer 5 by simply altering the illumination spectrum even whilst maintaining a similarly perceived illumination colour.

Metameric effects are seen when an object with a specific colour reflection or transmission spectrum is illuminated by a light source containing a specific colour spectrum. The overlap of illumination spectrum and the object colour spectrum determines the observed colour.

As an example, white illumination is generated either by using a light source like a tungsten lamp that emits at all wavelengths across the visible range, or by using a set of sources with correctly chosen but narrow wavelength ranges, for example three light emitting diodes (LEDs) at red, green and blue wavelengths. An object that only reflects or transmits at a single wavelength would always appear bright under the tungsten lamp illumination but would appear dark or bright under the LED illumination, depending on whether the reflection/transmission wavelength matches the wavelength of one of the LEDs. By switching between the two types of illumination, a message written in for example a coloured ink that only reflects at a yellow wavelength is switched from yellow to dark without an apparent change in the illumination colour.

As shown in Figure 3, the varying illumination can be achieved by utilising a number of individual light sources of different colour 13 and by switching between them, or by using a set of moveable colour filters 14. The metameric areas 7 of the packaging are incorporated, for example, by a printing process or by utilising coloured pigment in the base materials. The product 1 is illuminated from the front as illustrated in Figure 3 or illuminated from behind (not shown) in which case the product would be translucent.

In Figure 4, the display system is configured such that a polariser 8 is combined with a standard light source 2a in order to produce polarised illumination. The polariser may be mounted on a rotating mechanism in order to produce a spatially, or temporally, varying light source. In this way, moving images can be created in/on the packaging material of the product 1. This rotation facility allows variation of the illuminating light source, not only spatially and temporally but also by introducing variation in the degree, the angle or the type of polarisation that can be attained. Of course it will be apparent that alternative arrangements may be used for varying the polarisation.

In this example the facility to vary the polarisation state of the incident light is incorporated into the light source 2. By incorporating polarising 9 and birefringent 10 materials into the packaging, a varying coloured visual effect is created in the packaging to draw attention to the product 1. Such a feature allows a message or image on the packaging to change in appearance to the observer 5 by simply altering the polarisation state, even whilst maintaining a similarly perceived illumination.

Birefringent materials are anisotropic materials in which light experiences a different refractive index depending on whether it is polarised parallel to or perpendicular to a particular axis of the material. When the incident light is in any other polarisation state, the components of polarisation along the two primary axes effectively travel independently. Since the wavelength is reduced from the free-space value by the factor of the refractive index, the two components emerge from the material after a different number of wavelengths and they therefore have a phase difference between them. When they recombine, this phase difference gives rise to a change in the polarisation state compared to the incident light. The amount of the phase difference depends on the free-space wavelength and so this is a colour-dependent effect. When the light is subsequently analysed by passing through a polariser, since different wavelength components are in different polarisation states, they will be attenuated by different amounts and thus the light emerges with an altered colour spectrum.

In Figure 4 the display system is configured such that a polariser 8 is combined with a standard light source 2a in order to produce polarised illumination. In one example the polariser 8 comprises layers of polarising and birefringent materials, and can comprise a translating or rotating mechanism to allow the polarisation state of the projected light to be varied in degree, angle or type.

A further polariser 9 is incorporated into the packaging material which encompasses the product 1. The packaging, in this case, is formed from a layer of polarising material 9 and a layer of birefringent material 10, but other arrangements are possible. By varying the thickness of this birefringent layer, either completely or partially, different visual effects can be achieved. The birefringent layer may also be varied in angle or in material type to achieve different visual effects. The variation in the birefringent material may be patterned to form a desired shape or message. The variation in the birefringent material may be patterned with very fine features that are not visible at a distance whereby an intermediate colour or effect may be attained. The polariser may also be patterned to form a desired shape or message.

The incoming polarised light passes through the birefringent material 10 whereupon different wavelengths of light emerge with differing polarisation properties. Upon passing through the polariser 9, light at different wavelengths are diminished by differing amounts according to their incident polarisation. The light is therefore spectrally filtered by the polariser 9. All the light is now linearly polarised in the same direction. The light is reflected (specularly or diffusely) from the base packaging 11 and passes once again through the polariser 9. This light may be further attenuated by its passage through the polariser 9, depending on depolarising effects of the base packaging 11. The result is of variable colour change of packaging with variation of the incoming polarisation and with varying birefringent material 10 in the packaging.

The visual effect does not change appreciably with the angle of viewing. This is because most of the colour change occurs when the light first travels through the polariser 8. Since this is viewer independent, the colour change is also viewer independent. Figure 5 illustrates a variation on the display system of Figure 4 in which illumination 2 is placed behind the product 1. In this case the product 1 is translucent and there is no reflecting surface 11. The packaging comprises a polariser 9 and can also comprise one or more birefringent layers 10. The polariser and birefringent layers can be on either front or back surfaces of the product. As before, spectral filtering occurs when the light passes through the polariser 9, resulting in a visual effect. The example illustrated in Figure 6 uses a liquid crystal cell (LCC) 14 in combination with a fixed polariser 8', and the light source 2 to give an alternative method of generating a variable light source. The LCC 14 enables a rapid electronic, rather than mechanical, control of the projected light. The cell can produce linear, elliptical or circular polarisations as required. The colour change generated by a LCC would generally produce a uniform effect. If a non-uniform effect is required, a liquid crystal matrix (not shown) may be used as an alternative.

Figure 7 illustrates the detailed construction of a possible embodiment of the packaging according to the present invention. The polarising and birefringent materials are combined in the form of a label 15 attached to the product 1. The label comprises a number of birefringent layers 10 including a layer covering the whole label area and a layer shaped to only cover some areas. The label also comprises a polariser 9 that, in this case, covers the whole label area. The label further comprises a white backing layer 11 to diffusely reflect the light that passes through the polariser 9.

The variations in the layers of the packaging are formed for example by cutting, embossing, laser machining, physical machining or by thermal or chemical processing. The various layers in the packaging can be combined for example by a lamination process.

Claims

1. A display system comprising: a variable, illuminating light source; packaging for containing, in use, an object to be displayed, the packaging comprising an optical filter; and a polariser, wherein, in use, illuminating light from the light source passes through the optical filter to generate a lighting effect which is visible to a viewer.

2. The system of claim 1 , wherein the variable illuminating light source is provided by a light source in combination with the polariser, wherein the polariser is movable, in use, in the path of light between the light source and the packaging.

3. The system of claim 1 or 2, wherein the light source further comprises a movable birefringent layer.

4. The system of claims 1 to 3, further comprising an LCC adjacent to the light source.

5. The system of claims 1 to 4, wherein the packaging comprises at least one layer of a birefringent material.

6. The system of claims 1 to 5, wherein the optical filter introduces wavelength dependence to the lighting effect produced.

7. A display system comprising: a variable, illuminating light source; and packaging for containing, in use, an object to be displayed, the packaging comprising an optical filter, wherein, in use, illuminating light from the light source is varied in spectrum such that, in combination with the packaging, a metameric effect is produced which is visible to a viewer.

8. A display system comprising: an illuminating light source; and packaging for containing, in use, an object to be displayed, the packaging comprising an optical guide for receiving light from the light source, wherein the guide has light emitting regions formed therein which allow received light to be emitted from the guide to generate, in use, a lighting effect which is visible to a viewer.

9. A system according to claim 8, wherein the guide is a waveguide.

10. A system according to claim 8 or 9, wherein the light source is at least one LED.