| 摘要 |
An electrooptical liquid crystal system for use between a pair of electrodes, comprising a liquid crystal mixture and an optically transparent polymer medium, wherein: the transmission of incident light through the system is reduced in a first switched state, compared with a second switched state, essentially independently of the polarisation of the incident light; the component molecules of the liquid crystal mixture are irregularly orientated in an off state; at least one of the refractive indices of the liquid crystal mixture is substantially the same as the refractive index of the medium nm, or the ratio by weight of the liquid crystal mixture to the medium is at least 1.5:1; the liquid crystal mixture comprises at least one dielectrically neutral and at least one dielectrically positive liquid crystalline or monotropic compound; and the liquid crystal mixture comprises a total of up to 15% by weight of a dielectrically positive liquid crystalline or monotropic compound having two ring systems. |
