This application is based on, claims priority from, and claims the benefit of UK patent application no. 1309507.0, filed on 28 May 2013 and UK patent application no. 1322443.1 , filed on 18 December 2013.

This invention relates generally to the field of signage systems, and in particular to passive animated signage systems which incorporate lenticular lens technology. Signage is everywhere. From the high street, to roadways, to the interior of public buildings - these environments are marked with various displays of visual graphics that attempt to deliver information to passers-by. The main purpose of such signage is for communication purposes, to convey information about nearby services and facilities, to convey directions, to deliver warnings or safety instructions, and for identification purposes. Advertisements are also a form of signage, with marketeers deploying various strategies to make their signs more eye-catching and noticeable than other signs within the vicinity. In environments where a sign has an important message to convey, this important message can often become lost in the vast array of other elements that are within view. Road signs, for an example, have made use of simple pictograms or imagery, and have also used simple colours and shapes to try to create high visual contrasts. In more recent times, technology has been added to road signs to help to boost their visual identity. Signs have been illuminated with electric lighting systems such as neon displays and light- emitting diodes. Motorised elements have been added to some signs to add movement or animation, in an attempt to enhance their impact. However, all of these technologies require power, which has a considerable impact on the installation cost, unit cost, and the maintenance cost. For signage systems such as road signs, keeping the visual impact high, but the unit cost to a minimum, is crucial. The material value of road signs should also be kept to a minimum to reduce the possibility of theft, as signage systems are often stolen.

Various technologies have been incorporated into signage systems in the past to make them more eye-catching whilst keeping the unit cost of each sign to a minimum. Lenticular technology (i.e. making use of a lenticular lens), is one of these technologies.

Standard lenticular signs, however, can be unclear when viewed from different angles, and due to the construction of the layers that make up the sign, and the clarity of images used, ghosting and other undesirable effects can occur. This is not thought to be of such importance when being used for advertising signs, however when in use for road signs and other signage systems delivering a warning or important message, clarity of imagery becomes extremely important. Ghosting, blurring or any other similar effects that can occur to an image with existing lenticular signage systems may deliver an unclear message to a user.

The prior art shows a number of devices which attempt to address these problems in various ways.

EP 778,555 (Lovison et al) discloses a three-dimensional signage system that incorporates a lenticular split image that is process printed onto the second surface of a lenticular lens layer. The signage system incorporates lenticular technology to generate the effect of the image being three- dimensional. The signage system comprises a lenticular lens layer, a lenticular split image printed in light transmissive ink, a lenticular split covering comprising an opaque ink being selectively deposited against portions of the image to mask and unmask portions thereof, and a reflective layer. The masked portions are to alter the visual texture of the image, not to improve image clarity or ensure that a clear message is delivered.

EP 1 ,168,060 (Eastman Kodak) discloses a lenticular image comprising a flip image, with means to minimise image ghosting (having one image still visible whilst the other image is being viewed). The minimising of image ghosting is achieved through a transition region between the first and second interlaced images. This transition region attempts to eliminate pixel interference by isolating the images. The transition frame may comprise a background image, a gradual change in opacity of one image into the next or a colour shift between images. Whilst an attempt has been made to distinguish one image from the next, little detail is given as to how this would be achieved. The transition phase appears to be a rather complex phase involving a number of different elements.

Whilst the prior art appears to address the issue of incorporating cost- effective technologies into signage systems to improve their impact and effectiveness in delivering the message that they display, they do not provide any means of ensuring that this message is clear at all times. They do not provide sufficient means to prevent image ghosting or blurring, or other image defects and therefore do not ensure optical clarity of the image that is viewed by a user.

Preferred embodiments of the present invention aim to provide a signage system that delivers enhanced visual impact by using lenticular technology to create movement within an image whilst ensuring optical clarity of the information that the sign is to convey. The present signage system aims to reduce the issues with existing lenticular signage systems that suffer from ghosting, blurring and other image defects, thereby delivering a clearer message to a passer-by.

According to one aspect of the present invention, there is provided a signage system for displaying a lenticular image, the signage system comprising:

at least one passive or active light source;

a lenticular lens layer incorporating an array of lenticules; and

a printed lenticular image layer between the light source and the lenticular lens layer, said printed lenticular image layer comprising an interlaced image to correspond to said array of lenticules;

whereby said interlaced image comprises a printed ink layer of variable opacity or thickness so as to allow different amounts of light to pass through different portions of the interlaced image at different viewing angles.

The interlaced image may be digitally spliced.

The printed ink layer of variable opacity or thickness may be effective to allow specific amounts of light to pass through the image.

The interlaced image may be printed directly onto the back of the lenticular lens layer.

Alternatively, the interlaced image may be printed onto a substrate layer that is laminated or otherwise attached to the back of the lenticular lens layer. The substrate may comprise a transparent material. Alternatively, the substrate may comprise a translucent material.

Preferably, the light source comprises a passive light source. The passive light source may comprise a reflective or retroreflective material. The retroreflective material may be a light reflective vinyl, such as a polyester. Alternatively, the light source may comprise an active light source.

The active light source may be a digital display. Alternatively, the active light source may comprise at least one light- emitting diode.

The light source may optionally comprise a luminescent material. The printed lenticular image layer may be printed by one or more of the following printing processes: flexography, lithography, screen, inkjet. Other processes are of course also possible, and envisaged.

The printed lenticular image layer may comprise ultraviolet cured ink.

The lenticular image may comprise a flip effect image having a first image layer of a first opacity, and a second image layer of a second (lesser) opacity, such that when viewed from different viewing angles the image appears to brighten.

The interlaced image may comprise a transition phase of gradually varying opacity with a range from the first opacity to the second opacity to ensure a smooth transition of the lenticular effect of the signage system when viewed from different viewing angles.

The lenticular image may comprise a flip effect image having a first image layer of a first opacity, and a second image layer of a second opacity, such that when viewed from different viewing angles the image appears to disappear.

A road sign may comprise the signage system. An advertisement sign may comprise the signage system.

According to a second aspect of the present invention, there is provided a road, street or highway sign comprising the signage system of the first aspect.

According to a third aspect of the present invention, there is provided an advertisement or promotional sign comprising the signage system of the first aspect.

For a better understanding of the invention and to show how embodiments of the same may be carried into effect, reference will now be made, strictly by way of non-limiting example, to the accompanying diagrammatic drawings, in which:

Figure 1 shows a side view of one embodiment of a signage system, showing the layers that make up the system;

Figure 2 shows a single lenticule of the signage system of Figure 1 , showing incident light beams from three different viewing angles passing through the lenticule;

Figure 3 shows a side view of two different embodiments of the signage system with printed lenticular image layers comprising varying opacity, and thickness, of printed ink;

Figure 4 shows one arrangement of a signage system showing a typical road sign from three different viewing angles; and Figure 5 shows a close up of the printed lenticular image layer of the signage system of Figure 4, showing varying opacity of ink layer within the interlaced image. In the figures like references denote like or corresponding parts.

As shown in Figure 1 , a signage system 1 is made up of a plurality of layers that together generate passive animation in the signage system 1 when a passer-by moves past the signage system 1 . The signage system 1 comprises a lenticular lens layer 2 that comprises a plurality or array of lenticules 3. These lenticules 3 make up a lenticular lens, so that when viewed from slightly different viewing angles, different images are perceived through the lens. This can give an illusion of depth, of altering the size of an image, or appearing to generate movement or animation within an image. This can also change the overall optical quality of a section of the sign.

The simplest form of lenticular effect is known as a flip effect. This is where (when viewed from different viewing angles) one image appears to flip into the next image. Therefore from a first viewing angle a first image can be seen, and from a second viewing angle, the first image is at least partly concealed and a second image can be seen. The images are substantially viewed independently at different viewing angles.

The signage system 1 also comprises a light source 4, so that the image can be seen. It is very important to understand that this light source (here, a layer) 4 is either a passive light source or an active light source. A passive light source, which can operate/function without any source of power, here comprises means to reflect incident light beams, or to make use of light directed onto its surface. This passive light source may be a reflective or retroreflective layer 4 that may comprise a material that is designed to reflect incident light beams back towards the source of the light beam. Retroreflective materials are often used for signage systems, and in particular road signage systems, to ensure that when a vehicle's headlights are incident on the signage system, a considerable portion of the incident light is reflected back in the direction of the vehicle, to vastly increase the visibility of the signage system, and in particular the instructions, warning or message that it displays. Retroreflective vinyl is one example of the type of material that could make up the retroreflective layer, and one that is often used in signage systems. This retroreflective vinyl is available in a number of classes. Class 1 is the least reflective, and is commonly used for signage systems in car parks and on private roads. Class 2, also known as high intensity prismatic, is the most commonly used and can be found in most road signs. DG3, or microprismatic is the most reflective vinyl currently used within signage systems, and is often used for motorway signs and on roads which do not have additional illumination from streetlamps and suchlike.

It will be understood, however, that in many circumstances, materials which are simply reflective to some extent (as opposed to retroreflective) will be suitable. Reflective materials could be used, for example, where the signage system is employed (i.e. viewed) mainly during the day, so that daylight will be the main incident light. Equally, reflective materials may be appropriate where the signage is illuminated with an overhanging electric light, such as is found in road signage on side (minor) streets, for example.

The light source layer 4 may alternatively comprise an active light source, whereby the light source comprises its own means to generate and emit light. This will be particularly beneficial in environments where incident light beams prove insufficient. This light-emitting layer may comprise a plurality of light- emitting diodes, a digital display or similar light generating means. It may also be replaced by a self-illuminating material layer, such as a photo luminescent or luminescent material. Phosphorescent materials (which "absorb" light and then re-emit it, over time) are also envisaged.

Disposed between the lenticular lens layer 2 and the light source layer 4 is a printed lenticular image layer 6. The printed lenticular image layer 6 comprises printed ink layers of changing or differing opacity which are configured to work with the specific dimensions and placement of each of the lenticules 3 of a particular signage system 1 . It is important to note that the term "ink" is to be interpreted broadly, as signifying any suitable composition which can be applied to a substrate to form an image. Similarly, the term "printing" (and related terms) is to be interpreted as any process suitable to apply the "ink" to the substrate. In addition, and for the avoidance of doubt, it will be understood that the term "opacity" is used broadly, to indicate that, from a viewer's perspective, different amounts of light are allowed to pass through the interlaced image, at different viewing angles. In other words, a more "opaque" ink layer will reduce the overall amount of light which can pass through it, creating a relatively dark image, insofar as the viewer is concerned. On the other hand, a less "opaque" ink layer will increase the overall amount of light which can pass through it, creating a relatively light/bright image, from the viewer's perspective.

The printed lenticular image layer 6 may comprise inks that have been printed directly onto the back of the lenticular lens layer 2. Alternatively, the printed lenticular image layer 6 may comprise an additional layer of substrate onto which the image frames 7 have been printed prior to assembly between the lenticular lens layer 2 and the retroreflective layer 4. The printed lenticular image layer 6 may comprise inks that have been printed to form this layer, or onto a substrate, or a similar effect could be achieved by machining a layer of plastic to create the variable opacity and effectively to 3D print the printed lenticular image layer 6. Figure 2 shows a range of incident light beams 5 falling on an individual lenticule 3 of the lenticular lens layer 2, and shows how each of the incident light beams 5 are refracted by the lenticule 3 when passing through the lenticular lens layer 2, and through the printed lenticular image layer 6, and onto the passive light source layer 4. The incident light beams 5 that fall on the passive light source layer 4 are reflected back substantially or exactly in the direction in which they reach the passive light source layer 4.

The printed lenticular image layer 6 is made up of a series of image frames 7, with each image being made up of varying opacity of ink layer 8 due to the thickness of this ink layer 8. In short, a thicker layer of ink creates a more opaque layer, and vice versa. Alternatively, where precision printing techniques allow it, different parts of the ink layer could be printed with different inks, where those inks have different inherent opacities/darknesses. In addition, such different parts of the ink layer could be printed (with ink) in some regions, but not in others - creating a dotted or pixellated effect. In view of the very small size of the dots/pixels, the individual dots/pixels would not be perceptible to a viewer, but the effect of the dotted array/pixels, overall, would be to restrict the total amount of light passing though that part of the ink layer, and thus changing its opacity. The effect thus achieved is akin to so- called "optical mixing" where, at a micro-level, the dots/pixels can be detected, but where, at a macro-level, a human viewer cannot distinguish them - but can detect the overall effect. Figure 2 shows the printed lenticular image layer 6 comprising at least two image frames 7 interlaced together, and being made up of a varying opacity layer of ink 8. The layer of ink 8 is of different opacity to allow a particular proportion (i.e. amount) of incident light beams 5 to pass through the image frames 7 that make up the interlaced image 10, and therefore to be reflected back, such that a person viewing the signage system 1 is delivered the desired effect of transition between each of the image frames 7 that make up the interlaced image 10. The opacity of ink layer 8 allows for a portion of a sign to be brightened, by using an image frame of lesser opacity of ink layer. Likewise it may allow a portion of an image frame to disappear, or may effectively block out the light from the light source being transmitted through said portion of that image frame.

The varying opacity of ink layer 8 may allow for a transition phase to be created. The transition phase may be configured to be such an opacity that it assists with blending a first image frame 7 into a second image frame 7 when a passer-by moves past the signage system 1 and thereby views the signage system 1 from different viewing angles. The image frames 7 and the transition phase can create an illusion of depth in the image being displayed, or generate what appears to be an animated image to a passer-by when moving past the signage system 1 and viewing the signage system 1 from different viewing angles. A first image frame 7 may comprise a first frame of an animation and the second image frame 7 may comprise a second frame of an animation, with the transition phase providing a smooth transition by providing a different opacity of ink layer 8 to the image frames 7 of the first and second frames. The printed lenticular image layer may comprise more than two image frames 7, with a different transition phase printed to correspond between each pair of image frames 7.

To configure a printer to generate the printed lenticular image layer 6, at least two images are collected, flattened into individual frame files, and then digitally combined through a process called interlacing. This process generates the interlaced image 10. The interlaced image 10 can be printed directly onto the back of the smooth surface of the lenticular lens layer 2, or printed onto a transparent or translucent substrate and laminated (or otherwise attached) to the lenticular lens layer 2. The interlaced image 10 may be lithographic, flexo, inkjet or screen printed, or alternatively machined or moulded onto the lenticular lens layer 2 or substrate. Lithographic offset printing is typically used to ensure images of sufficient quality. The printing press or printing machine used must be capable of adjusting image placement in micrometer steps, to ensure that the interlaced image 10 (made up of the image frames 7 and transition phase 8) is aligned correctly with the array of lenticules 3.

When the image frames 7 are digitally combined, they are effectively sliced into strips, as shown in Figure 2. One image frame 7 is spliced with another image frame 7 and a transition phase, if required, is spliced therebetween. The transition phase may help to deal with ghosting of the image frames 7 whereby the first image frame 7 can still be seen when the second image frame 7 is being viewed. The transition phase can be used to ensure that a first image frame 7 cannot be seen (or at least is largely obscured) when the second image frame 7 is being viewed.

Figure 3 shows an array of lenticules 3, whereby each lenticule 3 is configured to coincide/co-operate with a first image frame strip 7, a transition phase strip, and a second image frame strip 7.

Figure 4 shows the signage system 1 of Figure 3 when viewed from three different viewing angles 9. At a first viewing angle 9A a viewer can view a first image A. At a second viewing angle 9B, the viewer views a second image B or transition phase. At a third viewing angle 9C, the viewer views a third image C. Images A, B and C in this example represent the arrows of a road sign to indicate a roundabout. Each of the images A, B and C are made up of different opacities of ink layer, to transmit different proportions of light through the printed lenticular image layer 6 at each viewing angle, and thereby alter the effect of each image that is being viewed from each viewing angle. The arrows of the example signage system 1 may brighten when a passer-by moves from position A to position B to position C. Or, at least a proportion of the interlaced image 10 may appear to brighten or illuminate. Alternatively, a portion of the interlaced image 10 may seem to disappear.

As shown in Figure 5, the printed lenticular image layer comprises strips of image frames of varying opacity of ink layer, such that when viewed from a first angle, a first intensity of light is emitted through the ink layer, and when viewed from a second angle, a second intensity of light is emitted through the ink layer, thus varying the clarity or brightness of the resulting image. When a portion of an image comprises a 100% opaque ink layer, no light is transmitted through this portion of the image, and therefore the reflective/retroreflective layer cannot be seen. When a portion of an image comprises no ink, or a 0% opacity ink layer, substantially all of the light is transmitted through the image, and the reflective/retroreflective layer can be visibly seen, appearing brightly. The degrees of opacity of ink layer between these two extremes allow for a creator of the interlaced image to alter the strength of the light that is transmitted through the printed lenticular image layer. By altering the strength in different proportions of each image layer, different effects can be created. An image, or a proportion of an image, can seem to disappear, or become brighter and therefore more eye-catching, or likewise can appear to dim to fade away and become less eye-catching to a passer-by.

The transition phase deals with certain disadvantages of existing lenticular image systems. The opacity (by virtue of the thickness in these examples) of the ink layer 8 may also help to deal with these design defects and ensure clarity of images and smoothness of transition. These design defects include double images, frame jumping, fuzzy images, image ghosting and image synchronisation.

The signage system described and exemplified herein is of course not limited for use within road signage applications, although it is extremely advantageous in this area to road users. The signage system may alternatively comprise or be incorporated within building signs, advertisement signs, emergency signage and signage for numerous other situations, where including some form of passive animation or movement can greatly increase the viewer's awareness and appreciation of, and engagement with a sign.

The reflective or retroreflective layer may be replaced by a light-emitting layer, such as a plurality of light-emitting diodes, a photo luminescent substrate, or similar arrangement whereby the signage system 1 is not reliant on incident light beams 5 to make the signage system visible in many different conditions. This is not shown in the drawings, but will be well-understood by those skilled in the relevant art. These arrangements can directly replace the retroreflective layer, whereby the signage system 1 emits its own light from the base layer or illuminative layer through the printed lenticular image layer 6 and through the lenticular lens layer 2.

It is also important to understand a further alternative.

In the specific embodiments illustrated, the variable opacity ink layers are integral with (i.e. form part of) the interlaced images themselves - in other words, it is the thickness/opacity of the ink layers which make up the image which give rise to the visual transition/flip effects.

It will be readily understood, however, that the interlaced images could, alternatively, be printed with a substantially uniform thickness/opacity, with an additional light transmissive layer being disposed above or beneath the image layer. This alternative embodiment, which is specifically envisaged by the applicant, could be implemented using a pre-printed/pre-prepared layer of material which is applied to the image layer in a separate manufacturing process step.

Thus, the applicant envisages that such layers could be made commercially available on a separate basis, for application to/use with existing/known interlaced image layers. In a further alternative embodiment, the varying opacity can be achieved by applying ink only to selected areas of the printed ink layer. In other words, the two-dimensional "density" of the image can be used to affect the perceived opacity of the layer. This can be explained by imagining each interlaced image layer as a grid, made up of a number of regularly spaced shapes such as (for example) squares or hexagons. Applying ink (of a particular inherent opacity) to some of the grid (i.e. "on top of" some of the shapes), but leaving other areas of the grid unprinted, will affect the overall opacity of that grid - in a pixellated manner. Thus, using a suitable substrate can allow the varying opacity to be achieved via selective printing of ink onto some parts only of the substrate. The applicants have found that a cellular structure, such as a honeycomb configuration allows this embodiment to work well. Whilst it will be understood that other configurations are also envisaged, a honeycomb structure, having an array of hexagonal cells (effectively "pixels") works particularly well.

With such an arrangement, varying the proportion of the tiny hexagons which are filled with ink affects the overall, perceived opacity of that particular part of the image. The effect can be varied still further by appropriate choice of a suitable ink - a darker (more inherently opaque) ink, applied to the same proportion of hexagons, will create a greater overall opacity than a lighter ink, applied in exactly the same areas. In one specific example, therefore, a first part of an image frame could have no ink applied (allowing a substantially total reflection - i.e. a bright image), a second part could have 60% of its cells/pixels "inked" with an 80% opacity ink (allowing a perceived reflection of about 50%), with a third part having 100% of the cells/pixels "inked" with the same ink, allowing a perceived reflection of only 20%.

In this specification, the word "comprise" has its normal dictionary meaning, to denote non-exclusive inclusion. That is, use of the word "comprise" (or any of its derivatives) to include one feature or more, does not exclude the possibility of also including further features.

All of the features enclosed in this specification (including the accompanying claims, abstract and drawings) and/or all of the steps of any method or process so disclosed, may be combined in any combination.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing specific, exemplary embodiment(s). The invention extends to any novel combination of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel combination of the steps of any method or process so disclosed. The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.