Optical: systems and elements – Absorption filter
Reexamination Certificate
2001-11-07
2003-03-18
Chang, Audrey (Department: 2872)
Optical: systems and elements
Absorption filter
C359S892000
Reexamination Certificate
active
06535341
ABSTRACT:
BACKGROUND OF THE INVENTION
Color light filters are known to the art for providing a single color of light, or at least a substantially single color of light, upon a plurality of colors of light in the visible light spectrum being transmitted thereto. The color of light provided is, of course, dependent upon the color of the color light filter. Such color light filters are widely used in the entertainment field, such as for example, in stage theaters, outdoor shows and other applications where relatively bright colored light is desired or required. The light for such applications transmitted to the color light filter is typically from what is referred to in the art as a white light source, or reflected from a white light source, and which white light source typically includes at least a portion of the colors of light in the visible light spectrum from violet, through blue, through green, through yellow-orange to red. Some white light sources also produce at least some ultraviolet light and, of course, upon such white light source becoming heated, the white light source radiates and produces at least some infrared light. Light is also used herein and in the appended claims as radiation, electromagnetic radiation, or energy that can affect the human eye.
As is further known to the color light filter art, and referring to
FIG. 1A
, the typical prior art color light filter includes a transparent, or least substantially transparent, base plastic material
18
which has either or both of its outer surfaces suitably coated with a colored dye
19
in the manner known to the art, or which base material
18
can have a colored dye diffused into either or both of its outer surfaces in a manner known to the art, or and referring to
FIG. 1B
, the base material
18
A can have colored dye
19
dispersed completely through the base material
18
A in the manner known to the art. Such prior art plastic base material
18
and
18
A may be a clear, or least substantially clear thermoplastic material such as polycarbonate, vinyl, or acetate or may be a thermosetting material such as polyester.
A typical prior art color light filter
10
and its implementation are illustrated diagrammatically in FIG.
1
. The prior art color light filter
10
is mounted in a suitable holder (not shown) in front of a light source
12
which may be, for example, the above-noted white light source. Light illustrated by the arrows identified by general numerical designation
14
is transmitted to the color filter
10
from the light source
12
and, for example, upon the color light filter
10
being provided with red dye as described above, the color filter
10
will be a red color light filter, and the red color light filter will allow red color light
16
to pass therethrough but the red dye provided in the red color filter
10
will absorb and block all other colors of light in the visible light spectrum contained in the light
14
from passing through the red color light filter.
Referring again to
FIG. 1
, the light source
12
is typically operated in the above-noted applications at 500 watts or above and upon the colored dye contained in the base material, as noted above, absorbing the colors of light as noted to prevent their passage through the color filter, heat is produced which can be sufficient to cause the color light filter
10
to degrade, lose its strength or structural integrity and fade. Such loss of strength, structural integrity or weakening can cause the color light filter
10
to wrinkle, or otherwise distort in shape, and fade thereby impairing, if not ultimately destroying, the ability of the color light filter
10
to produce a single color of light. This reduces the useful life of the color light filter
10
causing it to be replaced thereby increasing the cost of providing colored light. Further, in an application such as the above-noted theater application, the color light filter
10
may be located in a relatively inaccessible location in the theater which prevents the color light filter, upon weakening and fading as noted above, from being readily replaced such as during a theater production or performance.
Accordingly, there is a need in the color light filter for a new and improved color light filter having increased strength and an increased ability to withstand heat and maintain its structural integrity thereby providing the light filter with an increased useful life span. There is a further need in the art for a process of manufacturing such new and improved color light filter.
SUMMARY OF THE INVENTION
It is the object of the present invention to satisfy the foregoing needs in the color light filter art.
A color light filter satisfying the foregoing need and embodying the present invention may include a layer of substantially clear plastic material provided with colored dye of a selected color and for allowing light of the selected color to pass therethrough and the colored dye for absorbing and blocking the passage therethrough of light other than the selected color of light in the visible spectrum of light; and
a layer of clear thermosetting material laminated to the layer of substantially clear plastic material and for providing the layer of substantially clear plastic material with strength upon the layer of substantially clear plastic material becoming heated due to the colored dye absorbing light of the other colors of light.
The process of the present invention for manufacturing the color light filter of the present invention, and satisfying one of the foregoing needs in the art, may include the steps of providing a substantially clear layer of plastic material provided with a colored dye, providing a layer of clear thermosetting material, and laminating the layer of substantially clear plastic material provided with the colored dye to the layer of clear thermosetting material to provide the color light filter.
REFERENCES:
patent: 4802745 (1989-02-01), Okada et al.
patent: 4820619 (1989-04-01), Sanada et al.
patent: 5102213 (1992-04-01), Lee et al.
patent: 5254420 (1993-10-01), Otsuka
patent: 5631107 (1997-05-01), Tarumi et al.
rosco, technotes 2a, Color Filters for Entertainment Lighting, two (2) double-sided brochure pages.
Chang Audrey
Pritchett Joshua
Rhodes, Jr. R. Gale
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