Browse Prior Art Database

Ultraviolet Protecting Coating

IP.com Disclosure Number: IPCOM000078030D
Original Publication Date: 1972-Oct-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Haller, I: AUTHOR

Abstract

It is known that thin layers of liquid crystals of the 4,4'-disubstituted alpha-chlorostilbene type are degraded by the ultraviolet components of ordinary light. To overcome such degradation, there has been resorted to discrete optical filters, which substantially reduce the rate of such degradation and thereby insure substantially satisfactory lifetimes for liquid-crystal devices which comprise chlorostilbene.

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Ultraviolet Protecting Coating

It is known that thin layers of liquid crystals of the 4,4'-disubstituted alpha- chlorostilbene type are degraded by the ultraviolet components of ordinary light. To overcome such degradation, there has been resorted to discrete optical filters, which substantially reduce the rate of such degradation and thereby insure substantially satisfactory lifetimes for liquid-crystal devices which comprise chlorostilbene.

There is disclosed herein a composition which is suitable for use in the place of the discrete optical filters. The composition is applied to form a coating on the chlorostilbene liguid-crystal device that is to be protected from the UV light. It has been found that this composition actually is superior in its filtering function to commercially available UV filters and provides other advantages in the manufacture and use of these liquid-crystal devices.

The function of the optical filter is to absorb ultraviolet light of wavelengths in the region where the emission spectrum of the light source (sunlight, 400 to 300 nm; fluorescent light, 365 nm) and the absorbtion spectrum of chlorostilbene (385 to 300 nm) overlap. In accordance with the disclosure described herein, the filtering effect is achieved by dissolving a UV-absorbing visible-transparent dye in a film-forming polymer. Suitable dyes that may be employed for this purpose are those which are members of the 2-hydroxybenzophenone or the benzotriazolylphenol groups. Suita...