Ultraviolet light block and photocatalytic materials

Abstract

Nanoscale UV absorbing particles are described that have high UV absorption cross sections while being effectively transparent to visible light. These particles can be used to shield individuals from harmful ultraviolet radiation. These particles can also be used in industrial processing especially to produce solid state electronic devices by creating edges of photoresist material with a high aspect ratio. The UV absorbing particles can also be used as photocatalysts that become strong oxidizing agents upon exposure to LV light. Laser pyrolysis provides an efficient method for the production of suitable particles.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is a divisional of copending U.S. patent application Ser. No. 09 / 566,476 to Kambe et al., entitled “Ultraviolet Light Block And Photocatalytic Materials,” which is a continuation of U.S. Pat. No. 6,099,798 to Kambe et al., entitled “Ultraviolet Light Block And Photocatalytic Materials,” both of which are incorporated herein by reference.FIELD OF THE INVENTION [0002] The present invention relates to metal oxide particles that are effective at absorbing ultraviolet light for use in UV blocks and photocatalytic materials. The invention further relates to methods for the production of the metal oxide particles. BACKGROUND OF THE INVENTION [0003] While ultraviolet light can be useful in commercial processing, contact with ultraviolet light has a detrimental effect on biological organisms. Harmful ultraviolet light can come from both sun light and from artificial light sources. The risk from exposure to ultraviolet light from...

AI Technical Summary

Benefits of technology

[0005] Small particles, especially nanoscale particles, are useful as absorbers of ultraviolet light. Due to their small size, nanoscale particles can be relatively transparent to visible light. Similarly, the UV absorption spectrum depends on the particle diameters. Laser pyrolysis provides a important source of UV absorbing, nanoscale particles with relatively narrow distributions of diameters. The particles are useful for producing UV blocking materials. The particles are also very useful for producing sharp boundaries for electrical components on electronic circuit boards produced using photoresist. Also, the UV absorbing particles can be used as photocatalysts that create an oxidizing potential upon illumination with UV light.

Problems solved by technology

While ultraviolet light can be useful in commercial processing, contact with ultraviolet light has a detrimental effect on biological organisms.

The risk from exposure to ultraviolet light from natural sun light is increasing in portions of the world due to occasional significant drops in the UV-absorbing ozone layer.

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