Optics: image projectors – Gun – flashlight or battery operated type
Reexamination Certificate
1999-03-01
2001-03-27
Dowling, William (Department: 2851)
Optics: image projectors
Gun, flashlight or battery operated type
C353S080000, C353S119000
Reexamination Certificate
active
06206524
ABSTRACT:
DISCLOSURE
Background of the Invention
This present invention relates to graphic artistry and, more particularly, to an art transparency shadowgraph which is lensless, otherwise low cost, and yet is versatile.
As a general rule, most graphic artists, such as painters, do not have very much money. In some instances it is the parents of children whose creativity such parents want to encourage that want to reduce the amount of money being spent on, for example, a painting endeavor.
Most graphic artists want or desire an image projector that can be used to project a larger image of a smaller “image” (called an object in optics), on a canvas or the like. The projected image then can be traced or otherwise memorialized to allow the painter to paint a scene or portrait based on such projected image.
There generally are two types of projectors. One, called an opaque projector, reflects light from a scene onto a canvas or other surface. The other, called an image projector, is designed to be used with a transparent image (or “object”) to project an enlarged view of such image onto a surface.
Most image projectors now available have at least one lens, a lens for focusing the image on the desired surface. Lenses, however, cost money and those art projectors which are now commercially available typically are quite expensive.
There is another class of projectors which do not have a lens and typically project just shadows of an object, rather than an image of the full object. These lensless projectors are lumped together herein and called “shadowgraphs”. While shadowgraphs are available, most are special purpose ones that do not have the versatility needed by graphic artists. Moreover, some are fairly complex and/or otherwise expensive. Examples of special purpose shadowgraphs that are available include those described in U.S. Pat. Nos. 1,992,776, 2,048,365, 2,090,086, and 3,401,596.
SUMMARY OF THE INVENTION
The present invention is a lensless transparency shadowgraph which is especially useful by graphic artists. Besides not having a lens, it otherwise includes various features which result in the overall shadowgraph being quite versatile and yet of low cost.
As will be discussed in more detail below, a major feature of the invention is that, in common with many shadowgraphs, it includes a point light source and utilizes the same in such a way that a focusing lens is not needed. The position of this light source relative to the remainder of the projector is also changeable in a simple manner. While it is changeable manually along most axes relative to the projecting surface, a post-slidable collar arrangement is included to allow the position of the light source to be changed along one of the axes, simply by movement along a post. This will be discussed in more detail below.
The shadowgraph of the invention has many other features that also are responsible for it being a versatile, low-cost unit affordable by many. Another main feature is that the holder for the transparency provides a transparent backing for the same so that it will hold many different types of images (objects) to be projected without relying on such images for structural integrity. Most desirably, it is completely free of the structure for holding the light source so that for most degrees of movement it relies on manual movement for positioning by the artist himself/herself. It also simply relies on standard batteries, e.g., “D” flashlight batteries, to provide the low power electrical energy that is needed to energize the light source.
Other features and advantages of the invention either will become apparent or will be described in connection with the following, more detailed description of a preferred embodiment of the invention and variations.
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patent: 5477283 (1995-12-01), Casey
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DeMeo Palmer C.
Dowling William
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