LIQUID CRYSTAL SHUTTER

摘要

A liquid crystal shutter construction (18), suitable for a glass shield and a welding glass filter, which shutter construction is able to switch between a high light absorbing dark state and a low light absorbing transparent state, and vice versa, comprising low twisted nematic type liquid crystal cells with a twisting angle between 0 DEG and just below 90 DEG , and an electronic circuit output generating a variable cell driving voltage higher than about twice the threshold voltage for at least one of the liquid crystal cells and with a polarity switching frequency of less than 1 Hertz.