METHOD OF APPLYING VIEWING DEVICES

Abstract: A method for applying a viewing device to an interleaved image, thereby forming a special effects image, comprising: (a) providing a media having an interleaved image printed thereon; (b) providing a viewing device; (c) applying a wetting solution to at least one surface of said media or said viewing device; (d) placing said media over said viewing device with said wetting solution located therebetween; (e) aligning the viewing device with said media to obtain a special effects image; and (f) forcing out said wetting solution.

Description: METHOD OF APPLYING VIEWING DEVICES FIELD OF THE INVENTION The present invention relates broadly to methods of assembling layers for special effects images. Specifically, an alignment method is provided for use with lenticular lenses and black line screens that are layered over interleaved images. BACKGROUND OF THE INVENTION Three-dimensional viewing of images or pictures is based on the phenomenon that a human is able to integrate two dissimilar images of the same object received by the eyes and merge them into one image. Historically, to achieve 3-D views, a viewer would need to wear filters or glasses that combine multiple images (i.e.; combined stereo-pair) and enhance depth perception. The object is to achieve simulation of parallax -- the physical phenomenon that allows a viewer to perceive depth. More recent developments entail the utilization of lenticulated lens sheets or barrier strip systems, also known as black line screens, placed over interleaved images to achieve autostereography. Lenticulated sheets and black line screens are useful viewing devices that can be mounted on or layered onto images to provide the optics necessary for instigating depth perception (3D or stereography). Viewing devices are also useful in achieving other high impact/special effects images such as animated-type images that can be viewed with one eye. For example, a flip motion effect can be seen on specially designed images, where at one angle, one image is observable, while at a different angle, a different or second image is observable. U.S. Patent No. 5,942,062 teaches a method for laminating two sheets together, using a paired-roller laminator with low viscosity adhesive between the sheets. The adhesive is cured after the lamination process. Conventional lamination methods could lead to a variety of problems including for example, entrapped air between sheets (layers), poor bonding, or undesirable voids. U.S. Patent No. 4,927,238 provides a method and apparatus for depicting three-dimensional photographic images. The method in the '238 patent teaches that proper registration of rigid images can be attained through the use of various hardware, including bolts, springs, and pegs. The '238 method and apparatus may tend to be somewhat cumbersome and time consuming for practitioners. For semirigid images, the '238 patent teaches that the photographic image and the viewing screen can be laminated into a sandwich. U.S. Patent No. 5,942,062 relates to a method for controlling the spread of low viscosity adhesive during lamination of sheets. The method is particularly useful for laminating images to a lenticular array sheet to provide a three- dimensionally depicted image. U.S. Patent No. 5,959,718 teaches a method for aligning an image with a lenticular sheet. The lenticular sheet has lens elements that are individual, distinct, and immediately adjacent one another. The method for aligning the sheet to an image comprises: 1) directly sensing the locations of reference elements on the lens sheet and 2) writing portions of the lenticular image on the image receiving medium each of which is associated with a corresponding lens element, in accordance with the sensed position of the reference elements. Precise placement of direct application-type viewing devices onto images is desirable to ensure that special effects images can be achieved, with minimal distortion and maximum clarity. With conventional methods used in industry, the difficulty generally lies in the registration of the viewing device and the image. Images are typically provided with a double stick adhesive and a release liner. The practitioner can peel back a portion of the liner, then register the viewing device with the image, peel back the remaining liner and then place the layered assembly in a laminator. If the layers shift or were not initially, accurately registered, the final product is unacceptable and considered waste. Unacceptable products are generally those that viewers find to be unclear or unaesthetic. Furthermore, manufacturing efficiency and costs can be detrimentally affected if too much waste is produced. It would be advantageous to provide a method of aligning viewing devices that is flexible and user-friendly for an installer/practitioner yet achieves accurate mounting of a viewing device over an interleaved image. SUMMARY To accurately and easily apply viewing devices over an interleaved image, a method is provided comprising: providing a viewing device and an interleaved image, wetting the surface of either the viewing device or the image with a wetting solution, and aligning the viewing device and the interleaved image, then forcing out the wetting solution from between the substrates. In one aspect of the invention, a method of applying a lenticular lens over an interleaved image. In another aspect of the invention, a method of applying a black line screen over an interleaved image. As used herein, the following terms are intended to have the following meanings: "interleaved image" means a composite image made using the process of interlacing narrow slices or strips taken from multiple yet different images; "registration marks" is a series of monochrome lines that have an identical pitch to the pitch of the interleaved image; "pitch" means the distance from a point on an edge of a line or lens to a corresponding point on an edge of the next line or lens measured perpendicular to the line or lens; e.g., pitch can be measured by counting the number of lines or lenses per inch. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a method for applying viewing devices over interleaved images to produce special effects images. As used herein "special effects images" is used to describe a class of graphic images that are achieved by assembling (e.g. via layering) images with viewing devices to produce, for example, 3D graphics, flip images, animation, motion, flip-motion, or a combination thereof. A viewing device can either lie directly adjacent to an interleaved image or can be separated from the interleaved image by a spacer. Advantageously, the method provides a process that applies and aligns viewing devices over images and results in high quality and clean special effects images. To achieve high quality special effects images, viewing devices and printed images should be accurately aligned and registered. It has been surprisingly found that by applying a wetting solution prior to aligning layers or components of special effects images, high impact images with minimal distortion can be achieved. A further advantage of the present method of applying adhesive coated viewing devices or images using a wetting solution is that the assembled device can be free of flaws or markings from the assembly process. Thus, water marks are generally not visible after alignment and adhesion of the materials (layers). The present method is useful for a wide variety of imaged media, including for example, transparent or translucent images and opaque images. Conventional methods could result in marks that could detrimentally distort an image or provide an unclear three-dimensional image. Distorted images are generally unacceptable aesthetically. The use of the present invention of a liquid solution on special effects imaging substrates having a water immiscible adhesive can provide special effects images that are substantially free of detrimentally significant distorting marks or air bubbles. The alignment method of the invention provides a highly flexible method for assembling a special effects image. The method of the invention may be used in various locations and situations ranging from a fabricator shop or an automated manufacturing facility to an actual installation site which may be performed by hand. Actual installation sites where it would be advantageous to have the capability of on-site installation can include, for example, bus shelters, vending machines, airport concourses, retail stores, shopping malls, theater foyers, etc. Advantageously, the portability of a wetting (liquid) solution allows the present invention to be practiced in nearly any installation site, as long as the environmental conditions are reasonably clean or the site can be isolated from airborne debris. The method of the invention may be advantageously used for non-flat special effects images such as for example, curved 3D or flip images. Interleaved images are preferably printed on substrates that range in thickness from about 0.002 inches to about 0.020 inches. The substrate is preferably a film; however other suitable substrates for the methods of the invention include, for example, glass and paper. The interleaved images can be printed or deposited on the substrate by one of a variety of suitable methods, including screen print, offset print, photography, electrostatic, gravure, inkjet, digitization, thermostatic, electronic display, lithographic, flexographic, electrophotographic or other conventional imaging methods. The method of the present invention is useful in aligning various viewing devices, including for example, black line screens, slit plates or strip barriers that simulates parallax; or lenticular lenses. Lenticular sheets comprise a series of clear lenses, where each lens convex in shape. Common lenticular lenses are provided in hemi-cylindrical shapes; alternatively, the lenses can be parabolic in shape. A preferred lenticular sheet is described in U.S. Patent No^ 5,330,799 which teaches lenticular lenses that are suitable for aligning with an interleaved image to achieve 3D effect. (U.S. Patent No. 5,554,432 also provides a lenticular lens sheet that can impart autostereoscopic images.) Preferred black line screens are described in U.S. Reissue Patent Re. 35,029 and in a U.S. Patent Application entitled "Black Line Screen" filed on even date with the present invention, is commonly assigned and has Attorney Docket No. 55231USA1A.002. Where the viewing device is a substrate having black lines, it may be desirable to place at least one spacer between an imaged film and the black line screened substrate. A spacer is defined as any visible light transparent medium. Preferably, the spacer has a light transmissivity of at least about 75% (based on ASTM D1003). The spacer functions as a gap to provide a distance (depth) between an image and a viewing device to achieve flip or 3D effects. A preferred material for a spacer is a thermoplastic poly (methyhnethacrylate) polymer product commercially available from Elf-Atochem S.A., under the trade designation PLEXIGLAS. Other suitable materials that may be used as spacers include glass, acrylic or a polycarbonate material such as a product available from GE Plastics under the trade designation LEXAN. Alternatively, the spacer can be a volume of air between the interleaved image and the black line screen. Generally, the amount of air or the thickness of a spacer is a function relative to the pitch of a viewing device and the anticipated viewing distance of the observer from the special effects image. Generally, a special effects image assembly having a lenticular lens does not require a spacer. This is likely due to the fact that lenticular lenses are specifically designed to allow certain angles of the image to be seen. A lenticular lens can be considered to have a built-in or pre-fabricated spacer. Any of the substrates to be aligned may be coated with a clear adhesive. The coating step may be done on-site at the installation site or fabricator shop, or alternatively performed at a manufacturing facility to provide pre-coated substrates. Preferably, the adhesive is in the form of a pre-coat of a pressure sensitive adhesive cured onto substrate that can provide adhesion and immobilization between layers. More preferably, the adhesive is water immiscible to ensure that adhesive does not mix with the wetting solution and move out from between the layers when practicing the method of the invention. A preferred adhesive is taught in U.S. Reissue Patent No. 24,906. The Reissue patent teaches a pressure sensitive adhesive useful on sheet material, comprising a pressure sensitive adhesive (PSA) made from an acrylic base. To ensure clarity of the assembled special effects image, it is desirable that that the adhesive on a substrate be smooth. The substrate could be a spacer, the media which holds an interleaved image, a viewing device, or a combination thereof. Surface roughness of a PSA can be influenced by its release liner due to the close contact with which release liner has to the PSA. Thus, to achieve an optically clear special effects image, it is preferred that a substrate having a pre- coated PSA comprise a release liner that imparts low surface roughness. A very rough surface could lead to a hazy image. Smoothness of the adhesive also ensures continuous contact and good adhesion between layers. Quantitatively, the surface roughness of a release liner can be measured using the "RST Plus Surface Profiling system" which computes surface parameters that provide information about roughness and surface profile. (RST Plus Technical Reference Manual, Wyko Corp., April 1995 2nd ed. 980-078 Rev. A). The substrates having a pre-coated PSA preferably have a release liner that has a surface roughness, R t less than about 15μm; more preferably less than about lOμm. A preferred material for use as a release liners for PSA coated substrates is silicon- coated polyester (PET). In the practice of the invention, it is preferred and recommended that the surface of the interleaved image as well as the surrounding area are clean and free of foreign matter, prior to aligning a viewing device over the image. A component of this application method is a wetting solution, to be applied between the layers of the special effects image. An aqueous mixture of a surfactant in water is preferably used as a wetting solution in the process of the invention. Preferably, the surfactant is a mild synthetic detergent. The surfactant may be present in the solution at a level of about 0.1 wt% (weight percent) to about 20 wt%, where the balance of the composition is water. Preferably, the wetting solution comprises about 0.25 wt % to about 15 wt% of surfactant; more preferably, the wetting solution comprises about 0.5 wt% to about 5 wt% surfactant. Detergents (surfactants) containing oils, emollients, fragrances, dyes, etc. are not desirable as those components may result in application and or adhesion problems. It is therefore preferable that the detergent used in the liquid be compatible with the adhesive used to adhere the components of the special effects image. Suitable detergents useful for the practice of the invention include clear liquid (hand) dishwashing detergents such as the product available under the trade designation JOY, available from Procter & Gamble (Cincinnati, OH). In a preferred method of the invention, the wetting solution is sprayed onto the image side of the film or substrate. Application of the mixture may be performed by using a conventional sprayer. Alternatively, the wetting solution can be poured onto the substrate. The imaged surface should be completely wet for optimum alignment and positioning. More preferably, the imaged surface is thoroughly flooded with the wetting solution. Once the imaged surface is thoroughly wet, the viewing device can then be placed or positioned over the interleaved image. Taking advantage of the slippery wet surface, a user can then manipulate, adjust or reposition the viewing device to ensure maximum clarity and three-dimensional effect. For optimum stereographic or 3D effect, the viewing device should be matched or be in alignment with the interleaved image. An accurate alignment is achieved when the interleaved image transforms to a special effects image that can be clearly observed. For example, in the case of black line screens and interleaved images that optionally have registration marks, proper alignment is achieved when the registration marks appear either substantially opaque or substantially clear. A light source is generally preferable in the practice of the invention to provide sufficient illumination for ensuring proper alignment of the viewing device's pitch to the registration marks of the interleaved image. The light source preferably projects light from behind the image especially in cases where the image is non-opaque (i.e., translucent or transparent). For black line screens, a spacer may be positioned between the screen and the interleaved image substrate. Alternatively, a spacer may be pre-attached or adjacent to either the media or the black line screen. As used herein, "adjacent to" means that the surface between a media and a spacer, or the surface between a spacer and a black line screen, are in contact with each other, attached, or mechanically connected; preferably, the surfaces are adhesively attached. In instances where a spacer is used, the alignment process utilizing a wetting solution may be performed for aligning the spacer over the interleaved image as well as for aligning the viewing device over the spacer (in combination with the interleaved image). After alignment, the wetting solution may be pushed out from between the substrates by squeegee, sponge or other force application device. If bubbles become entrapped between any of the substrates, a pin or other sharp, round pointed tool may be used to puncture the film. The entrapped air or wetting solution can then be pressed out. Alternatively, the trapped air or solution can be removed by spraying the area and squeezing it out with rapid squeegee or sponge strokes.

Claims: What is claimed: 1. A method for applying a viewing device to an interleaved image, thereby forming a special effects image, comprising: a) providing a media having an interleaved image printed thereon; b) providing a viewing device; c) applying a wetting solution to at least one surface of said media or said viewing device; d) placing said media over said viewing device with said wetting solution located therebetween; e) aligning the viewing device with said media to obtain a special effects image; and f) forcing out said wetting solution. 2. The method according to Claim 1 further comprising an interim step g) applying an adhesive to a surface of said media, wherein said step g) is performed prior to applying said wetting solution. 3. The method according to Claim 1 further comprising an interim step g) applying an adhesive to a surface of said viewing device, wherein said step g) is performed prior to applying said wetting solution. 4. The method according to Claim 1 further comprising an interim step g) applying an adhesive to a surface of said media and to a surface of said viewing device, wherein said surfaces upon which adhesive is applied are placed in contact with each other, wherein said step g) is performed prior to applying said wetting solution. 5. The method according to Claim 1 wherein said viewing device is a black line screen. 6. The method according to Claim 1 wherein said viewing device is a lenticular screen. 7. A method for applying a black line screen viewing device to an interleaved image, thereby forming a special effects image, comprising: a) providing a media having an interleaved image printed thereon; b) providing a spacer; c) providing a black line screen viewing device; d) applying a wetting solution to a first surface, wherein said surface is a surface of said media or a surface of said spacer; e) contacting said media with said spacer, having said wetting solution located therebetween; f) applying a wetting solution to a second surface, wherein said second surface is a surface of said spacer or a surface of said black line screen; g) contacting said spacer with said black line screen, having said wetting solution located therebetween; h) aligning said viewing device with said media to obtain a special effects image; and i) forcing out said wetting solution from between said media and said spacer, and from between said spacer and said black line screen. 8. A method for applying a black line screen viewing device to an interleaved image, thereby forming a special effects image, comprising a) providing a media having an interleaved image printed thereon, said media being adjacent to a spacer; b) providing a black line screen viewing device; c) applying a wetting solution to at least one surface, wherein said surface is a surface of said spacer or a surface said viewing device; d) contacting said spacer with said black line screen, having said wetting solution located therebetween; e) aligning said viewing device with said media to obtain a special effects image; and f) forcing out said wetting solution from between said spacer and said black line screen. 9. A method for applying a black line screen viewing device to an interleaved image, thereby forming a special effects image, comprising: a) providing a media having an interleaved image printed thereon; b) providing a black line screen viewing device, said viewing device being adjacent to a spacer; c) applying a wetting solution to at least one surface, wherein said surface is a surface of said media or a surface of said spacer; d) contacting said media with said spacer, having said wetting solution located therebetween; e) aligning said viewing device with said media to obtain a special effects image; and f) forcing out said wetting solution from between said media and said spacer. 10. The method according to Claim 7 further comprising an interim step j) applying an adhesive to a surface of said media, wherein said step j) is performed prior to applying said wetting solution to said first surface. 11. The method according to Claim 7 further comprising an interim step j) applying an adhesive to a surface of said viewing device, wherein said step j) is performed prior to applying said wetting solution to said second surface. 12. The method according to Claim 7 further comprising an interim step j) applying an adhesive to a surface of said spacer, wherein said step j) is performed prior to applying said wetting solution. 13. The method according to one of Claims 1 and 7 wherein said media is pre- coated with an adhesive. 14. The method according to one of Claims 1 and 7 where said viewing device is pre-coated with an adhesive. 15. The method according to Claim 7 where said spacer is pre-coated on at least one surface with an adhesive. 16. The method according to one of Claims 13, 14 and 15 wherein said adhesive is a pressure sensitive adhesive. 17. The method according to Claim 7 wherein said interleaved image comprises a registration mark border. 18. The method according to Claim 7 wherein said wetting solution comprises water and a surfactant. 19. The method according to claim 18 wherein said surfactant is present in said wetting solution at about 0.1 wt% to about 20 wt%. 20. The method according to claim 18 wherein said surfactant is present in said wetting solution at about 0.25 wt% to about 15 wt%. 21. The method according to claim 18 wherein said surfactant is present in said wetting solution at about 0.5 wt% to about 5 wt%. 22. The method according to claim 7 wherein said black line screen comprises a polyester film.

Inventors: LEE CHARLES C, MORRIS TERRY L, ODEN JAMES L, LEE, CHARLES, C., MORRIS, TERRY, L., ODEN, JAMES, L.
Applicants: 3M INNOVATIVE PROPERTIES CO, 3M INNOVATIVE PROPERTIES COMPANY
Application year: 2000
Main classification: G02B27
IPC codes: G02B27, G03B35, G03C9