1. Field of the Invention
The present invention relates generally to stereoscopic viewers and more particularly to a foldable viewer that can be placed in a magazine or similar publication for advertising or promotional purposes. In one form of the invention a protective backing integral with the foldable viewer is included to form a postcard which allows the viewer to be sent in direct mail without the need for an additional mailing envelope. The invention is also directed to the single blank used to form the foldable viewer and the postcard embodiment.
2. Prior Art
Collapsible viewers are well known devices in the art that have been constructed in various shapes and sizes, some of which are relatively expensive to manufacture. Most viewers are made from cardboard or paperboard and usually include a pair of optical lenses aligned with a pair of stereoscopic images appearing on slides, film strips, or other transparencies. The stereoscopic images take on a three-dimension effect when the user views them through the optical lenses.
Usually, the user holds the viewer up to a light source so that background light can illuminate the transparencies and produce the three-dimensional effect. Some prior art viewers have been constructed as box-like enclosures to create a darkened area between the optical lenses and the transparencies. This darkened ara helps enhance the three-dimensional effect and increases the clarity and illusion of reality of the image. There are problems, however, associated with prior art collapsible box-type viewers that have diminished their usefulness.
Generally, most box-type viewers are constructed from a single cardboard blank having numerous flaps and tabs that must be folded and placed within appropriate slots that are also formed on the blank. The design of most box-type viewers allows the viewer to be collapsed from the assembled or viewing position to a flattened position for storage. This collapsibility feature generally increases the complexity of the blank and usually requires the blank to be preassembled to create the foldable viewer. Once the blank has been preassembled, the finished viewer can be easily collapsed and reassembled by its user.
The intricacy of these blanks, however, usually requires the manufacturer to preassemble the viewers by hand, preventing the use of high speed machinery to assemble the finished product. As a result, a manufacturer usually has to hire additional labor to preassemble the blanks, thus reducing production speed and decreasing profits.
As an alternative, a manufacturer can sell unassembled blanks to its buyers, leaving the buyers to assemble the foldable viewers. However, the preassembly can be quite tedious and may require elaborate instructions to permit the user to properly construct the finished product. In many cases, the viewer may be so complicated to assemble that the usr loses interest in it and may even discard it, rather than take the time to assemble it properly.
The thickness and the number of walls or panels making up prior art viewers can also create a thick profile that prevents the viewers from being used in certain applications. For example, prior art viewers have not been placed in magazines or similar publications for advertising or promotional purposes since each viewer would cause an undesirable bulge in the magazine, a feature that is not acceptable by most national magazines. In fact, most national magazine publishers have strict thickness requirements for any insertion to prevent this unwanted bulge. While some prior art viewers can be folded somewhat flat for mailing purposes, the thickness of most prior art viewers is usually too large to permit a publisher to place them in publications. As a result, prior art foldable viewers have not been effectively used as an inexpensive advertising medium that can be easily inserted into magazines and distributed to consumers.
As an alternative, the blank that forms the viewer could possibly be placed in a magazine. However, the elaborate assembly needed to construct most viewers would be detrimental since many consumers may not bother to constuct the device to view the advertised products. For these reasons, advertisers have refrained from using prior art viewers to advertise their products. Advertisers appear to be more willing to use foldable viewers for advertising purposes provided that the viewers are relatively inexpensive to manufacture and are simple to construct.