Flexible ultraviolet radiation transmitting filters
US4167490A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 22, 1975 |
| Grant date | Sep 11, 1979 |
| Priority date | — |
| Expiry date | Dec 22, 1995 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31786
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Flexible filters capable of transmitting radiation in the spectral range of 315 to 380 nm and absorbing radiation in the spectral range of 400 to 550 nm consist essentially of a thin flexible film, e.g., polyethylene terephthalate containing or having coated thereon a dye in a concentration of 15 to 60 mg/dm.sup.2 and optionally, as a component of the coating, a thermoplastic organic binder, e.g., cellulose acetate butyrate, present in the coating with the dye, said dye being of the formula: ##STR1## where R.sub.1 is lower alkyl of 1 to 5 carbon atoms; R.sub.2 and R.sub.3, which may be the same or different, are selected from the group consisting of R.sub.1, 2-cyanoethyl, 2-hydroxyethyl and ##STR2## or form a saturated 5- or 6- membered ring; R.sub.4 is taken from the class consisting of lower alkyl of 1 to 5 carbon atoms, aryl or alkaryl of 6 to 9 carbon atoms, and aralkyl. The filters are useful in exposing dual response photosensitive materials with ultraviolet radiation sources which contain appreciable quantities of visible radiation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.