| 摘要 |
1,161,039. Temperature indicators. NATIONAL CASH REGISTER CO. Jan. 23, 1968 [Feb.27, 1967], No.3495/68. Heading G1D. [Also in Division H4] A temperature indicator comprises a continuous film 12 of polymeric material having dispersed therein droplets 11 of a liquid capable of assuming a cholesteric mesophase in a predetermined temperature range, and thereby exhibiting a colour change in the light reflected from the droplets. The droplets are preferably of between 5 to 25 microns in size and the liquid preferably comprises a cholestrol derivative, e.g. cholesteryl carbonate or cholesteryl nonanoate, the composition of the liquid being varied to vary the temperature range in which the spectral colour change occurs. The liquids also exhibit irridescence in the associated temperature range. The film 12 preferably comprises polyvinyl alcohol or a polyacrylate material. Other examples of materials for use in the liquid or as the film 12 are given in the Specification. The film 12 may be disposed on a substrate 10 which may be opaque e.g. black, or a coloured layer 13 may be interposed between the substrate and the film 10. The droplets 11 may be disposed as a single layer in the film 12 or may provide a number of layers. Droplets having different colourchange ranges may be disposed in the one film 12.
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