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US 5,028,792 AGranted
System for the visualization of exposure to ultraviolet radiation
AssigneeXytronyx, Inc.
InventorKary B. Mullis
Life of this patent
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Abstract
Photochemical systems for the direct visualization of exposure to ultraviolet radiation that effect visible color changes involving a process in which a photoacid is formed upon irradiation of a nitro-substituted aromatic aldehyde with ultraviolet light and wherein proton transfer to a dye causes the dye to undergo a visible color change. The system undergoes such color change to an extent directly proportional to the cumulative amount of ultraviolet incident thereupon.
Claims1
An ultraviolet dosimeter that indicates cumulative exposure to ultraviolet radiation that comprises:
- a) a film that is substantially impermeable to oxygen and changes from one color to a different color in response to exposure to ultraviolet radiation that comprises a mixture of:
- i) from about 50 to about 99 weight percent polyvinyl alcohol;
- ii) from about 0.5 to about 50 weight percent water;
- iii) from about 0.01 to 5 weight percent of at least one acid-sensitive dye that is substantially insensitive to changes in temperature;
- iv) from about 0.05 to about 5 weight percent of a surfactant;
- and
- v) from about 1 to about 40 weight percent of a photoacid progenitor comprising a bisulfite adduct of an ortho nitro-substituted aromatic aldehyde that is converted into a photoacid on exposure to ultraviolet light;
- b) an ultraviolet radiation transparent moisture barrier adhered to and surrounding said film;
- c) a color standard chart that is affixed to said dosimeter and is in close visual proximity to said film;
- and
- d) means to affix the dosimeter to user.
8 more elements
Dependencies are inferred from the claim text.