Optical filtering element including fluorescent material
First Claim
1. A substantially solid, dry, substantially transparent optical filter element which absorbs, on the average, from about 10% to about 99%, and transmits, on the average, from about 90% to about 1% visible radiation having wavelengths in the range of about 400 nm to about 700 nm including:
- optical means, said optical means including at least one substantially discrete fluorescent means having two opposed surfaces, said fluorescent means including fluorescent material which is substantially stable and which has the ability to absorb transversing visible radiation of one or more wavelengths which is incident on one surface of said fluorescent means and to then emit visible radiation from its opposed surface, substantial amounts of said emitted radiation being at different wavelengths than the radiation absorbed, said fluorescent means being of a thickness of no greater than about 1 mil (0.0254 mm) between its opposed surfaces so that the incident side of said fluorescent means does not scatter, reflect or emit substantial amounts of radiation.
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Accused Products
Abstract
Optical filtering elements having two opposed surfaces and including at least one thin layer of stable non-reflective fluorescent material provide transparent articles which, when exposed to incident electromagnetic radiation at one surface of the fluorescent layer, absorb certain wavelengths within the fluorescent layer and emit other wavelengths at the opposed surface of the fluorescent layer. In preferred embodiments, when radiation (light) in the visible range (about 400 nm to about 700 nm) is incident on the element from one side, certain wavelengths of radiation which transverse the element are absorbed in the fluorescent layer and other radiation of greater, but also visible wavelengths are emitted from the opposed side without fluorescent light being reflected by the fluorescent layer at the incident side. Methods of forming such optical filtering elements include providing a thin coating or layer including stable fluorescent material on an optical element by means of a solution or coating composition including stable fluorescent material, forming transparent sheets or films containing stable fluorescent material and utilizing them as optical filtering elements or incorporating them in an optical structure, or in other ways incorporating thin layers of stable fluorescent material within an optical element. In order to avoid glare and reflection of fluorescent light at the incident side, preferred embodiments require layers of stable fluorescent material which are about 1 mil (0.0254 mm) or less in thickness.
121 Citations
14 Claims
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1. A substantially solid, dry, substantially transparent optical filter element which absorbs, on the average, from about 10% to about 99%, and transmits, on the average, from about 90% to about 1% visible radiation having wavelengths in the range of about 400 nm to about 700 nm including:
optical means, said optical means including at least one substantially discrete fluorescent means having two opposed surfaces, said fluorescent means including fluorescent material which is substantially stable and which has the ability to absorb transversing visible radiation of one or more wavelengths which is incident on one surface of said fluorescent means and to then emit visible radiation from its opposed surface, substantial amounts of said emitted radiation being at different wavelengths than the radiation absorbed, said fluorescent means being of a thickness of no greater than about 1 mil (0.0254 mm) between its opposed surfaces so that the incident side of said fluorescent means does not scatter, reflect or emit substantial amounts of radiation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
Specification