| 摘要 |
<p>A thermo-chromic, plastic optical fibre 4 preferably made of thermoplastic material where the attenuation of light through the fibre 4 may increase when the temperature is raised above a threshold. The thermochromatic fiber 4 may have a softening temperature, above which there is a threshold attenuation and the fibre 4 stretches under a load. This is possibly for use with a sensor to measure the change in optical transmission and in the strap of a tag 2 for securing to someone or something to ensure the strap is not tampered with by heating and stretching. Another invention is a method of make an optical fibre where thermo-chromatic material is used to form the core and a characteristic of optical transmission changes during the forming and is returned to its initial value. The characteristic may be the attenuation of one of more wavelengths of light and UV light could be used in the returning.</p> |
