Demodulation, Inc.

James E O'Keefe, Jr

Howard Horst Liebermann

William C LaCourse

Alexis G Clare

Wesley A King

A metallic glass-coated wire is formed by drawing a hollow glass fiber from a container in which molten alloy is entrained and solidified. Interference stresses extant between the glass coating and the alloy core of the wire are produced by systematically controlling thickness and mechanical elastic properties of the glass. The interference stress is tailored by selection of glass thickness and chemistry to optimize wire drawing process conditions, such as drawing temperature and strain rate. In addition, the interference stress is especially tailored to assure physical integrity of the glass-alloy composite wire product. Local property variations along the wire length are minimized, facilitating production of discrete wire segments especially suited for use in EAS applications.

Engineered glasses for metallic glass-coated wire

A glass-coated amorphous metallic microwire is encoded with multi-bit digital information. Encoding is achieved magnetically, optically or through a combination of magnetic and optical encoding processes. Magnetic encoding is carried out by modifying the constituent magnetic domain structure through selective relief of interfacial stress between the glass coating and the amorphous metallic alloy core. It is also achieved by selective surface crystallization of the amorphous metallic core in order to produce a controlled magnetic bias field. Optical encoding is associated with the glass coating. It is readily achieved by fluorescent element deposition, patterned removal of fluorescent element coating, Bragg grating, and thermally activated pattern deposition. The magnetic and optical multi-bit encoding approaches for glass-coated amorphous metallic microwire can be used individually or collectively in either a redundant or a complementary manner. Encoded microwire of the instant invention can be assembled into tags for electronic article surveillance and into numerous other structures as well.

Multi-bit encoded glass-coated microwire and articles composed thereof

A drawn glass-coated metallic member has a thermal contraction coefficient differential such that the thermal contraction coefficient of the glass is less than that of the metallic member. The thermal contraction coefficient differential is maintained within a predetermined range during drawing. Drawn glass is placed under residual compression, interfacial bonding between said glass and said wire is substantially uniform, and surface cracking and bond breaks between metal and glass are substantially prevented. Optical properties of the glass coated microwire provide a basis for enabling multi-bit encoding capability. Advantageously data encoding is achieved optically, magneto-optically or using a combined magnetic and optical encoding mechanism. The duplex material constitution of the glass coated microwire permits imparting of data thereon by selection and processing of the glass. Data implantation is readily achieved in-line, during an initial drawing operation, or as a separate post-draw process. Reading of data on optically encoded glass coated microwire is readily accomplished by optical or magnetic methodology, or a combination thereof.

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Westwood, NJ, United States of America

James E O'Keefe, Jr