GB2568300A

GB2568300A - Multi-layer image display apparatus for producing a pseudo-3D effect and method of preparing such

Info

Publication number: GB2568300A
Application number: GB1718710.5A
Authority: GB
Inventors: George King Michael; Michael King Max
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-11-13
Filing date: 2017-11-13
Publication date: 2019-05-15
Also published as: GB201718710D0

Abstract

A multi-layer image display apparatus 10 for producing a pseudo-3D effect comprises a first graphic layer 12 including a first image 28a, a second graphic layer 14 including a second image 28b, and spacing means such as light-transmissible sheet 16 for spacing apart the graphic layers. Lighting means 18 is proved for backlighting the graphic layers. The first image is at least substantially the same as the second image, and the graphic layers are positioned so that the first image is at least in part registered to the second image. The graphic layers may be formed on or in a substrate or each graphic layer may alternatively be formed on or in their own respective substrates. The substrates may be formed from lustre paper and the graphic layers may be inkjet printed.

Description

Multi-Layer Image Display Apparatus For Producing A Pseudo-3D Effect And Method Of Preparing Such

The present invention relates to a multi-layer image display apparatus, and a method of preparing such a multi-layer image display apparatus.

Graphic works, including manually produced or mechanically reproduced artworks, posters, photographs and advertising displays are commonly displayed in a specially adapted image display apparatus, which may illuminate its contents, enabling the clear display of the graphic works in the absence of other illumination, and often resulting in a more vibrant colour profile, for coloured works.

In particular, it is known to backlight a graphic work, and more particularly a photograph, in an image display apparatus. In one simple image display apparatus, a photograph is held in a frame which includes a recess, behind the photograph, for holding a candle or an electric light bulb, to provide illumination. In other known designs, an image is inkjetprinted onto an acrylic diffuser, and backlit by LEDs.

Typically, such inkjet-printed images, when backlit, provide adequately clear coloured images. However, when the backlighting is removed, under natural lighting the image invariably appears dull, and lacks colour contrast. This is generally considered a result of the limited colour range available in conventional inkjet printing. Single-layered inkjetprinted images also cannot convey depth perception, even when backlit, which is necessary to create a pseudo-3D effect.

The present invention seeks to provide a solution to all of the abovementioned problems with the prior art.

According to a first aspect of the invention, there is provided a multi-layer image display apparatus for producing a pseudo-3D effect, the multi-layer image display apparatus comprising a first graphic layer including an image, a second graphic layer including an image, spacing means for spacing apart the first and second graphic layers, and lighting means for backlighting the first and second graphic layers, wherein the first image is at least substantially the same as the second image, and the first and second graphic layers are positioned so that the first image is at least in part registered to the second image.

Advantageously, the registration of the first image at least in part to the second image results in the display of a composite image to a viewer, in which registered portions of the image provide the appearance of greater depth, and a wider range of colours, than any ηοη-registered portions of the image.

Preferably, the first graphic layer and/or the second graphic layer are formed on or in an at least in part light transmissible substrate. In such an arrangement, the graphic layers may be illuminated without frontlighting.

The first graphic layer and the second graphic layer may be formed on or in the same said at least in part light transmissible substrate. In such a case, the substrate of the first and second graphic layer may also include or be part of the spacing means.

Alternatively, each of the first graphic layer and the second graphic layer may be formed on or in a different said at least in part light transmissible substrate. In this case, the two respective substrates of the first graphic layer and the second graphic layer may advantageously be separated by spacing means formed from a different material, which may alter the optical properties of the multi-layer image.

The at least in part light transmissible substrate or substrates of the first and second graphic layers may be beneficially formed from a pulp-based material, such as paper or card, and most preferably from lustre paper. Such substrates allow the printing of a highquality graphic layer thereon, while having sufficiently low light transmittance that the light emitted by the light source is substantially attenuated by passing therethrough.

To provide a high level of surface contrast gloss, the lustre paper may have a surface coating with a blend comprising a mineral-based pigment and a polymeric binder.

For any at least in part light transmissible substrate, the at least in part light transmissible substrate may preferably have an area density between 180 and 300 gm'²; such area densities correlate with favourable light transmittance properties.

Beneficially, when the first and second graphic layers are formed or in different at least in part light-transmissible substrates, the said at least in part light-transmissible substrates of the first and second graphic layers may be affixed to either side of the spacing means, and most preferably by a transparent adhesive film, to fix the relative position of the first and second graphic layers and the spacing means, and to ensure that the first and second images remain registered unto each other.

The or each substrate could also be formed from an in part light transmissible glass, and the commercial availability of a large range of such glasses with different optical properties may advantageously give the designer of the multi-layer image display apparatus a greater degree of control over the light transmittance of the substrate. For the same reason, the or each substrate may furthermore alternatively be formed from a polymeric material.

In any case, at least one of the first and second images may preferably be a non-grey scale image, to allow the provision of a colour, sepia, or monochromatically toned multi-layer image.

Additionally or alternatively, at least one of the first and second graphic layers may be inkjet printed onto the respective substrate thereof, to ensure that the portions of the image of the first and second graphic layers to be registered are substantially identical.

The first image may be identical to, or only immaterially different from, the second image. Advantageously, in this case the entire image of the graphic layer of the first graphic layer may be registered to the entire image of the graphic layer of the second graphic layer, so that a single multi-layer image with enhanced colour profile and depth perception, is displayed.

The spacing means preferably includes a light-transmissible sheet, so that it may lie between the first and second graphic layers without occluding the images thereof. The light transmissible sheet may be formed at least in part from a polymeric material, such as any one of poly(methyl methacrylate), bisphenol A polycarbonate, polyethylene terephthalate, polyvinyl butyral and polystyrene. Any one of these materials may be advantageously provided as an optically clear sheet, or as a non-transparent, lighttransmissible sheet, as required.

The thickness of the light-transmissible sheet may preferably be between 1 mm and 2.5 mm, as a thickness in this range results in realistic depth perception of the multi-layer image.

The light source may comprise a plurality of LED panels aligned to backlight the first and second graphic layers. Such a light source may provide a consistent illumination across the area of the first and second graphic layers, while requiring a low power input for a high luminous flux output.

According to a second aspect of the invention, there is provided a method of preparing a multi-layer image display for producing a pseudo-3D effect, the method comprising the steps of: a) providing a first graphic layer including a first image; b) providing a second graphic layer including a second image, the first image being at least substantially the same as the second image, and the first graphic layer being spaced apart from the second graphic layer by spacing means; c) obtaining positional indicia of at least one of the first graphic layer, the second graphic layer and the spacing means; d) predetermining a desired relative orientation of the first and second graphic layers from the positional indicia; and e) using the positional indicia, setting the first and second graphic layers in the desired relative orientation of the first and second graphic layers, so that the first and second images are at least in part registered unto one another.

Advantageously, this method allows the accurate preparation of a multi-layer image display in accordance with the first aspect of the invention, either by hand or at least in part via an automated process.

Preferably, the first graphic layer and the second graphic layers comprise at least in part light-transmissible substrates on which the first and second images are mounted, the spacing means comprising a light-transmissible sheet, and during step e) the respective substrates of the first and second graphic layers are affixed to either side of the lighttransmissible sheet using an optically clear adhesive.

As noted hereinbefore, the use of an optically clear adhesive minimizes the effect of the adhesive used to adhere the first and second graphic layers to the light-transmissible sheet on the image quality.

The adhesive may be advantageously applied to the substrates of the first and second graphic layers by cold lamination during step e), to avoid heat damage to the first and second graphic layers when adhesive is applied thereto.

The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a schematic front-on view of a multi-layered image display apparatus in accordance with the first aspect of the invention;

Figure 2 shows an exploded perspective view of the multi-layered image display apparatus shown in Figure 1; and

Figure 3 shows a cross-section across the first and second graphic layers of the multi-layered image display apparatus shown in Figures 1 and 2, and a lighttransmissible sheet therebetween.

Referring to Figures 1 and 2 of the drawings, there is shown a multi-layer image display apparatus 10 for producing a multi-layer image 15 with a pseudo-3D effect, the multilayer image display apparatus 10 comprising a first graphic layer 12, a second graphic layer 14, spacing means, such as the light-transmissible sheet 16 shown, spacing apart the first and second graphic layers 12, 14, and lighting means adapted to backlight the first and second graphic layers 12, 14 simultaneously, such as the backlighting unit 18 shown.

As shown in Figure 2, the multi-layer image display apparatus 10 may further include a front outer frame element 20, which may provide a perimeter surround for the assembled multi-layer image display apparatus 10. A dust-protection sheet 22, may also be provided, to overly the at least the first graphic layer 12, and to prevent ingress of dust into the multi-layer image apparatus. For further protection of the graphic layers 12, 14, and optionally, to modify their appearance, an inner frame element 24 may be provided. The inner frame element 24 may include a bevelled outer element 24a, and optionally an optically clear or otherwise light-transmissible inner element 24b. Preferably, the backlighting unit may comprise a back outer frame element (not shown) engageable with the front outer frame element 20. In this way, the dust-protection sheet 22, inner frame element 24, first graphic layer 12, light-transmissible sheet 16, and second graphic layer 14 may be contained by the front and back outer frame elements, in that order, from the front outer frame element 20 to the back outer frame element (not shown).

The first and second graphic layers 12, 14 each include a substrate 26 and an image 28 applied to the substrate 26. The image 28 may be a reproduction of a photographic image, or a computer-generated image. Conceivably, the image could also be recorded directly onto the or each substrate 26 of the first and second graphic layers 12, 14, especially by painting. A photographic or computer generated image may be applied to the substrate 26 by inkjet printing, laser printing or lithographic printing, among other methods. Any further number of graphic layers, each containing an image, may also be contemplated, in order to create more complex composite multi-layer images.

The first image 28a is substantially the same as the second image 28b, and the first and second graphic layers 12, 14 are positioned so that the first image 28a is at least in part registered to the second image 28b.

It is to be understood that the first image 28a may be substantially the same as the second image 28b in so far as a significant part, but not necessarily the majority, of the first image 28a is identical or only immaterially different to a corresponding part of the second image 28b, or vice versa. The first image 28a may also be entirely identical, or only immaterially different to the second image 28b.

This does not preclude the possibility of the first graphic layer differing from the second graphic layer, in order that a desired optical effect may be achieved, as long as the first and second images are substantially the same as defined hereinabove. Furthermore, any distortion or modification of the image of one or each of the first and second graphic layers, when the said graphic layers are viewed abstracted from the multi-layer image display apparatus, should not be considered to result in a substantial difference between the respective first and second images, in so far as the distortion of the image of one or each of the first and second graphic layers is compatible with the registration of the first image to the second image.

Registration, that is, of the first image 28a to the second image 28b, may include any modification of the relative position of the first and second graphic layers 12, 14 which results in a multi-layer image 15 display whereby, with appropriate lighting, a viewer of the multi-layer image 15 display can view a unitary multi-layer image 15 produced by the first and second graphic layers 12, 14, which has the appearance of one or both of the first or second images 28a, 28b, but with a pseudo-3D effect, and enhanced colour. Furthermore, registration of the images may also be achieved by manipulation of the shape of the first and/or second graphic layer. For example, if the first and/or second graphic layer has a suitably flexible substrate, the first and/or second graphic layer may be flexed to be slightly concave or convex to achieve registration.

In particular, the images of the first graphic layer and the second graphic layer may be registered to be slightly offset, so that when spaced apart they produce a multi-layer image which provides sufficient depth perception to create a pseudo-3D effect from all viewing angles.

Preferably, and as shown in Figure 2, the substrates 26a, 26b of the first and second graphic layers 12, 14 respectively are substantially planar. In any case, the or each substrate 26 of the first and second graphic layers 12, 14 may preferably be at least in part light transmissible.

In particular, the substrates 26a, 26b may be formed from a pulp-based material, such as paper or paperboard. While any light transmissible pulp-based material may be contemplated, paper with moderate to high contrast gloss is to be preferred. Pulp-based material with moderate to high contrast gloss, herein referred to as lustre paper, results in a greater proportion of specular reflection over diffuse reflection than paper with low contrast gloss, producing a brighter, clearer image when the multi-layer image 15 is viewed without backlighting, for example in natural daylight. Pulp-based materials with very high contrast gloss could also be used, although they may result in excessive specular reflection for display of the multi-layer image 15 with front-lighting. Furthermore, the mottle, that is the optically detectable unevenness of the surface of the pulp-based material, should be minimized to avoid observable blemishes in the multi-layer image.

A desirable reflectance for the surface of the or each substrate 26 in any case would be between 0.3 and 0.8.

The or each substrate 26 may include a glossy coating 30, and in particular a glossy coating 30 including a mineral-based pigment and a polymeric binder. For example, the mineral-based pigment may be kaolinite (A12O3-2SiO2^-2H2O), calcium carbonate (CaCCh), titanium dioxide (T1O2), barium sulphate (BaSCU) or a combination of one or more such pigments. The polymeric binder may be an acrylamide-acrylic acid copolymer, or an artificial latex, such as a styrene-butadiene copolymer. It may be advantageous for the glossy coating 30 of the or each substrate 26 to include one or more light or UV stabilizers. For example, the glossy coating 30 could advantageously be impregnated with a hindered amine light stabilizer composition, and/or a benzotriazole based UV stabilizer, such as 2-hydroxphenylbenzotriazole.

To ensure enough light transmission is possible through two or more layers of the substrate 26 for a bright multi-layer image 15, while achieving sufficient attenuation to prevent glare from the light source, substrates 26 with an area density between 180 and 300 gm'² are preferred. A thicker paper card stock, or paperboard may also be preferred to prevent damage or distortion of the graphic layers under cold lamination, and particularly under cold roll lamination, and a substrate with an area density of 240 gm'²is especially preferable.

Alternatively, the or each substrate 26 may be formed from another material. In particular, polymeric materials, including poly(methyl methacrylate), or glass, could be considered. In either case the or each substrate 26 should be light transmissible but preferably not transparent, to ensure adequate attenuation of the light emitted by the backlighting unit 18 by each substrate. However, transparent substrates could be used, with appropriate modulation of the intensity of the backlighting unit 18.

In a preferred embodiment of the invention, one or each of the first and second graphic layers 12, 14 includes a non-greyscale image, and in particular colour image. However, one or both of the first and second graphic layers 12, 14 could alternatively include a black and white, sepia, monochromic, or monochromatically toned image. A graphic layer including a single block colour may act effectively as a colour filter to modulate the colour of a multi-layer image, wherein the image of another graphic layer thereof is a polychromic image. In one conceivable embodiment of the invention, each respective graphic layer of a plurality of graphic layers may include a different monochromic image, to provide a colour multi-layer image. In such a case, the said monochromic images may optionally be so registered to provide an anaglyph image, with stereoscopic depth perception achievable when viewed through anaglyph glasses.

It is found that the provision of a multi-layer image 15 from two such graphic layers 12, 14 may provide a brighter image with greater colour contrast than that produced by a conventional single-layer backlit image. It is anticipated that this may be due to the coloured areas of the graphic layers acting as filters, and preferably absorptive filters, such that when corresponding coloured areas of the graphic layers are registered, twostage filtration of light passing therethrough is achieved.

The light-transmissible sheet 16 preferably may be provided as an at least in part transparent, or optically clear sheet. Various materials may be contemplated for the lighttransmissible sheet 16, depending on the desired optical properties thereof, including glass, or polymeric materials, such as poly(methyl methacrylate), bisphenol A polycarbonate, polyethylene terephthalate, polystyrene, and polyvinyl butyral.

The light-transmissible sheet 16 may preferably be thin, with a thickness of between 1 mm and 2.5 mm preferred. Such a thickness of the light-transmissible sheet 16 is advantageous, as the first and second graphic layers 12, 14 are sufficiently separated in use for depth perception to be achieved across a range of viewing angles without, or with a minimal, offset between the first and second images 28a, 28b, in a direction perpendicular to the thickness of the light-transmissible sheet 16. Light-transmissible sheet 16 thicknesses of below 1 mm may be considered, but in this case, an offset between the first and second images 28a, 28b may be required to achieve depth perception. A lighttransmissible sheet 16 thickness of 1.5 mm or greater is particularly advantageous due to the enhanced rigidity of such a light-transmissible sheet 16.

In order to fix the first and second graphic layers 12, 14 such that the images 28a, 28b of the graphic layers 12, 14 are registered to each other, the first and second graphic layers 12, 14 may be adhered to either side of the light-transmissible sheet 16. This may be achieved with a light-transmissible adhesive 32, and most preferably, an optically clear or transparent adhesive.

Any such light-transmissible adhesive 32 may be a pressure sensitive adhesive, and may preferably be UV stabilised to prevent discolouring of the adhesive on exposure to solar radiation. Furthermore, the use of UV stabilized adhesive may prevent or reduce UV damage to the layers. Acrylic-based adhesives may be considered, and in particular acrylic, methacrylic and cyanoacrylic acid derived acrylic-adhesives. The adhesive 32 may be directly applied to the light-transmissible sheet and/or the graphic layers 12, 14 and/or the substrates 26a, 26b thereof, but most preferably may be provided as an adhesive film, to be cold laminated or vacuum pressed onto the light-transmissible sheet 16 and/or the graphic layers 12, 14 and/or the substrates thereof 26a, 26b. Cold lamination is to be understood to comprise lamination performed at under 50 degrees Celsius. If the adhesive 32 is provided as an adhesive film, the adhesive film preferably has a total thickness of less than 150 pm, including the thickness of the adhesive layers.

Suitable adhesive films, for cold lamination, are commercially available under the brand name Drytac (RTM) SynArt, from Drytac Europe Limited of Fishponds, Bristol, UK. Drytac (RTM) SynArt film includes an optically clear polyester film coated on either side with a pressure sensitive acrylic adhesive, the adhesive layers covered with a siliconized polyester release liner. The total thickness of the film and the two adhesive layers is approximately 54 pm.

Other spacing means may also be considered which are capable providing a separation between the substrates 26a, 26b of the first and second graphic layers 12,14 respectively. In particular, the spacing means may be provided as a substantially planar, lighttransmissible or opaque, intermediate frame element having a central aperture, or a plurality of central or non-central apertures, either such that the intermediate frame element may lie between the first and second graphical layers, or such that the mediate frame element may contain the first and second graphic layers. Alternatively, the spacing means could conceivably be provided as a plurality of clips or clasps, or as one or more blocks adhered to the substrates 26a, 26b of the first and second graphic layers 12, 14.

The backlighting unit 18 may preferably include a plurality of LED panels (not shown), aligned to backlight the first and second graphic layers. In this case, the LED panels may lie approximately parallel to the first and/or second graphic layers. The preferred luminance of the LED panels may lie between 3000 and 12000 lumens, and a luminance of between 5000 and 8000 lumens, and most preferably between 6000 and 6500 lumens is found to provide particularly good colour fidelity. Each LED panel may have its own separate driver unit, typically with power 5 to 50 W, and may operate on a current between 0.2 and 0.6 A imparted thereby. Preferably, the driver unit is enclosed within the multi-layer image display apparatus 10, and it may in particular be located in a cavity in the backlighting unit 18, behind the LED panels.

Other lighting means may be considered. For instance, the lighting means could be provided as a plurality of, for example, LED, lights situated around an edge of the spacing means, especially when the spacing means are provided as a light-transmissible sheet, and the graphic layers backlit via a mirror located behind the graphic layers which reflects light from the lights around the edge of the spacing means onto the back of the graphic layers.

A general method of preparing a multi-layer image display apparatus 10 as hereinbefore described is also contemplated. In a first stage of the process the first graphic layer 12 is provided; this may be via the inkjet or lithographic printing of the first image 28a onto a pulp-based substrate, via the inkjet, flexographic or thermal transfer printing of the first image 28a onto a polymeric substrate, or by the manual application of the first image onto a pulp-based or polymeric substrate. When inkj et printing is used, a twelve colour printing process is to be preferred, although a spot colour process may also be considered for enhanced range of colours.

In the case where the substrate of the first graphic layer is also the substrate of the second graphic layer, and the said substrate is the spacing means, the next step of the process is to obtain positional indicia of the first graphic layer, so as to predetermine a desired relative orientation of the second graphic layer. Positional indicia of the first graphic layer may be obtained by optical inspection of the first graphic layer, which may be automated, via a charge-coupled device (CCD) or photomultiplier tube (PMT) scanner, allowing digital analysis of the first graphic layer and the first image thereof. Alternatively, the first graphic layer may be optically inspected by hand, using a single lens or microscope, and optionally a finely graduated ruler or callipers, and the positional indicia thereby identified. From the positional indicia, the desired relative orientation of the second graphic layer, to provide a multi-layer image with desired characteristics, and such that the first and second images are at least in part registered unto one another, may be determined. The second graphic layer may then be applied to the substrate via any of the techniques mentioned hereinabove with respect to the application of the first graphic layer, or any other suitable technique, so that the second graphic layer is set in the desired orientation relative to the first graphic layer, and the first and second images are at least in part registered to each other.

When the substrate 26a of the first graphic layer 12 is instead different to the substrate 26b of the second graphic layer 14, as shown in Figure 2, the second graphic layer 14 may first be applied to the substrate 26b thereof via any of the techniques hereinbefore described, or any other suitable technique. Positional indicia of at least the first and second graphic layers 12, 14 may then be obtained. In one exemplary method, the spacing means may include or be provided as an at least in part light-transmissible sheet 16, and positional indicia of the first and second graphic layers 12, 14 and the light-transmissible sheet 16 may be obtained via optical inspection thereof.

Optical inspection may be carried out manually, for example, with a lens or microscope. The first graphic layer and the second graphic layer 12, 14 may then be set relative to each other, to achieve registration, at least in part, of the first and second images 28a, 28b, by first affixing the substrate 26a of the first graphic layer 12, or the first graphic layer 12, to the light-transmissible sheet 16, and then affixing the substrate 26b of the second graphic layer 14, or the second graphic layer 14, to the light-transmissible sheet 16 in a desired orientation predetermined from the positional indicia.

The affixing of the first and second graphic layers 12, 14 may be temporary, for example using a clear optical tape, while the desired orientation of the first and second graphic layers 12, 14 is achieved by a repeated stepwise process of realigning the second graphic layer 14 and/or the first graphic layer 12, and optically inspecting the resulting multilayer image 15 to identify if the desired orientation has been achieved. Optical inspection of the multi-layer image 15 may be advantageously conducted over a back-lit worktop, so that the relative orientation of the first and second graphic layers 12, 14 may be quickly assessed qualitatively, by the appearance of the resulting multi-layer image under backlighting.

Once the desired relative orientation has been achieved, the substrates 26a, 26b of the first graphic layer and the second graphic layer 12, 14 may be fixed permanently to the light-transmissible sheet 16, via the application of the optically clear or otherwise lighttransmitting adhesive 32, especially as hereinbefore described, to the substrates 26a, 26b of one or both of the first and second graphical layers 12, 14, and/or the light-transmissible sheet 16. The adhesive 32 may be applied using cold lamination, and cold roll lamination is most preferable, although other techniques such as vacuum pressing may be considered. In any case, adhesive 32 application may beneficially occur in a dust-free environment, to prevent trapping of dust or other small particles in the adhesive 32 which may blemish the multi-layer image 15.

When the spacing means are not provided as a light-transmissible sheet, but instead as a non-light-transmissible sheet with one or more image apertures, a frame element, or a plurality of clips or clasps, the relative orientation of the first and second graphical layers may be achieved by manual optical inspection with the spacing means applied, and subsequent realignment should the first and second graphical layers not be in a desired orientation, in a manner analogous to that hereinbefore described with respect to the case when the spacing means are provided as a light-transmissible sheet.

In the mass production of a suitable multi-layer image, it may be desirable to automate the process of realigning the first and second graphic layers. This may be achieved by providing two respectively separate feed paths for the substrates of the first and second graphic layers, such that the two feed paths meet in a registration chamber. In the registration chamber, the first and second graphic layers may be aligned by one or more adjustment elements, e.g. rollers in one or both feed paths. The alignment of the first and second graphic layers may then be inspected by measuring the attenuation of a lowintensity laser beam across a selected area of the first image and the second image, and confirming that the attenuation is within a desired range. If the attenuation of the laser beam is within the desired range, the substrates may then proceed along their respective feed paths to be affixed unto each other, or onto a spacing means such as a lighttransmissible sheet. Otherwise, the first and second graphic layers may again be aligned by one or more adjustment elements, and the alignment inspected until the attenuation of the laser beam does fall within the desired range, to ensure that the first graphic layer and the second graphic layer are aligned in the desired orientation.

It is therefore possible to provide a multi-layer image display apparatus for producing a pseudo-3D effect, the multi-layer image display apparatus including a multi-layer image having a first graphic layer and second graphic layer, both including a respective image, such that the images of the first graphic layer and the second graphic layer respectively are substantially the same to each other. Such a multi-layer image display apparatus may advantageously allow the display of the multi-layer image both by back-lighting the multi-layer image, for instance with an intense LED light source, and by front-lighting, especially with natural light, such that in either case the multi-layer image results in enhanced colour and depth perception over any one of its component graphic layers. It is also possible to provide a method of preparing such a multi-layer image display apparatus, both manually and in mass production.

The words ‘comprises/comprising’ and the words ‘having/including’ when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components, but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

The embodiments described above are provided by way of examples only, and various other modifications will be apparent to persons skilled in the field without departing from the scope of the invention as defined herein.

Claims

1. A multi-layer image display apparatus for producing a pseudo-3D effect, the multi-layer image display apparatus comprising: a first graphic layer including a first image; a second graphic layer including a second image; spacing means for spacing apart the first and second graphic layers; and lighting means for backlighting the first and second graphic layers; wherein the first image is at least substantially the same as the second image, and the first and second graphic layers are positioned so that the first image is at least in part registered to the second image.

2. A multi-layer image display apparatus as claimed in claim 1, wherein the first graphic layer and/or the second graphic layer are formed on or in an at least in part light-transmissible substrate.

3. A multi-layer image display apparatus as claimed in claim 2, wherein the first graphic layer and the second graphic layer are formed on or in the same said at least in part light-transmissible substrate.

4. A multi-layer image display apparatus as claimed in claim 2, wherein each of the first graphic layer and the second graphic layer is formed on or in a different said at-least in part light transmissible substrate.

5. A multi-layer image display apparatus as claimed in claim 3 or 4, wherein at least one of the at least in part light-transmissible substrates is formed of a pulp-based material.

6. A multi-layer image display apparatus as claimed in claim 5, wherein at least one of the at least in part light-transmissible substrates is formed from lustre paper.

7. A multi-layer image display apparatus as claimed in claim 5 or claim 6, wherein at least one of the at least in part light-transmissible substrates has an area density between 180 and 300 gm'2.

8. A multi-layer image display apparatus as claimed in claim 4, or any one of claims 5 to 7 when dependent on claim 4, wherein the at least in part light-transmissible substrates of the first and second graphic layers are affixed to either side of the spacing means.

9. A multi-layer image display apparatus as claimed in claim 8, wherein the at leastin part light transmissible substrates of the first and second graphic layers are affixed to either side of the spacing via a transparent adhesive film.

10. A multi-layer image display apparatus as claimed in any one of claims 2 to 9, wherein at least one of the substrates is formed from an at least in part lighttransmissible glass.

11. A multi-layer image display apparatus as claimed in any one of claims 2 to 10, wherein at least one of the substrates is formed from a polymeric material.

12. A multi-layer image display apparatus as claimed in any one of the preceding claims, wherein at least one of the first and second images is a non-greyscale image.

13. A multi-layer image display apparatus as claimed in any one of the preceding claims, wherein at least one of the first and second graphic layers is an inkjetprinted graphic layer.

14. A multi-layer image display apparatus as claimed in any one of the preceding claims, wherein the first image is identical to, or only immaterially different from, the second image.

15. A multi-layer image display apparatus as claimed in any one of the preceding claims, wherein the spacing means includes a light-transmissible sheet.

16. A multi-layer image display apparatus as claimed in claim 15, wherein the lighttransmissible sheet is formed at least in part from a polymeric material.

17. A multi-layer image display apparatus as claimed in claim 16, wherein the lighttransmissible sheet is formed at least in part from a composition selected from a group comprising: poly(methyl methacrylate), bisphenol A polycarbonate, polyethylene terephthalate, polyvinyl butyral and polystyrene.

18. A multi-layer image display apparatus as claimed in any one of claims 15 to 17, wherein the light-transmissible sheet has a thickness of between 1 mm and 2.5 mm.

19. A multi-layer image display apparatus as claimed in any one of the preceding claims, wherein the lighting means comprise a plurality of LED panels aligned to backlight the first and second graphic layers.

20. A method of preparing a multi-layer image display apparatus for producing a pseudo-3D effect, the method comprising the steps of:

a. providing a first graphic layer including a first image;

b. providing a second graphic layer including a second image, the first image being at least substantially the same as the second image, and the first graphic layer being spaced apart from the second graphic layer by spacing means;

c. obtaining positional indicia of at least one of the first graphic layer, the second graphic layer and the spacing means;

d. predetermining a desired relative orientation of the first and second graphic layers from the positional indicia; and

e. using the positional indicia, setting the first and second graphic layers in the desired relative orientation of the first and second graphic layers, so that the first and second images are at least in part registered unto one another.

21. A method, as claimed in claim 20, wherein the first graphic layer and the second graphic layer comprise at least in part light-transmissible substrates on which the first and second images are mounted, the spacing means comprising a lighttransmissible sheet, and wherein during step e), the respective substrates of the first and second graphic layers are adhered to either side of the light-transmissible sheet using an optically clear adhesive.

22. A method, as claimed in claim 21, wherein during step e), the optically clear

5 adhesive is applied to the substrates of the first and second graphic layers by cold lamination.