Cholesteric liquid crystal of the reentrant type and a temperature-detecting device entailing the use of a liquid crystal of this type

摘要

Cholesteric liquid crystals of the so-called reentrant mesogenic type obtained by mixing a substance such as a cholesterol ester having molecules of the "chiral" type with a liquid crystal of the so-called reentrant nematic type such as a substance corresponding to the general formula: <IMAGE> where R is an alkyl or alkoxy or alkylcarbonate group with: R'=H or CH3 and X is an organic radical such that CH=N, CH=CH, C 3BOND C or COO. The use of a liquid crystal in accordance with the invention serves to obtain a temperature-detecting device in which, in contrast to conventional cholesteric devices, the reflected light changes from blue to red when the temperature rises.