Low-loss face diffuser films for backlit signage and methods for using same
Assignee3M Innovative Properties Company
InventorsDavid G. Freier, Neal T. Strand, Scott R. Kaytor, Frank L. Deyak
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Abstract
A low-loss, diffuser film is provided for translucent surface(s) of lighted signage. The film has little absorptivity and has partial transmissivity and partial reflectivity. Luminance efficiency and brightness are significantly improved over conventional films used in backlit signage. A luminance efficiency prediction equation is also provided to aid in selection of diffuser films and interior surfaces of the lighted sign cavity. A combination of effects of diffuser films and a diffuse reflective films lining the interior surfaces of the lighted sign cavity is unexpectedly greater than their sum of effects operating alone.
Claims11
A lighted sign, comprising a translucent facing side, sidewall interior surfaces, a backwall interior surface, and a light source within the lighted sign, wherein said facing side comprises a low-loss, partially diffuse-reflective and partially diffuse-transmissive diffuser film having a reflectivity of from about 50% to about 70%, a transmisivity of from about 30% to about 50%, and an absorptivity from about 0% to about 15%, and said interior surfaces comprise an interior surface film and have a reflectivity of at least about 90% as determined by a ASTM E1164-94, wherein the diffuser film provides an increase in luminance efficiency of the lighted sign over a lighted sign that does not have such diffuser film applied therein.
Dependencies are inferred from the claim text.