| abstract |
Electro-optical liq. crystal (LC) system comprises, between 2 electrodes opt. deposited on substrates, a position dielectric LC mixed with an optically transparent medium (A). The LC molecules in the 'off' position adopt an irregular orientation and the refractive index of LC and matrix are about the same and/or the quotient of mass of LC to that of (A) is 1.5 or more. In one of the 'off' and 'on' positions, the system has a lower transmission than when in the other position, regardless of the polarisation of the incident light. The new feature is that the LC medium includes at least one chiral dopant (I). USE/ADVANTAGE - These systems are esp. useful in architectural structures (windows, room dividers, sun roofs, etc.) but can also be used in display (esp. matrix-display--matrix-display) devices. They provide (1) optimum slope of the electro-optical characteristic graph (i.e. to match the driving electronics) and/or (2) high contrast between opaque and transparent states, with low haze in the transparent state. |