Nematic liquid crystal infrared plane polarizers

In a LCTV-VIDIC system, infrared plane polarizers are really needed. Because of the high technology precision and price of wired-grid polarizers, we have hoped to obtain infrared plane polarizers as we have in the visible region. In our experiments, we obtained them by field controlling homogeneously aligned LC (Δε > 0); molecular realignment to tended to be parallel with the direction of the field and the incident unpolarized light. The conditions for realizing n-LC infrared plane polarizers are an infrared n-LC (Δε > 0 for us), an infrared film electrode, and a controlling field. There are two kinds of these polarizers: a direct field controlling n-LC to realign (V=2 v, T=100 ms, P=85%) and field controlling polymer dispersed n- LC (V=30 v, T=40 ms, P=80%). The properties (V, t) are the same as in a display. V and Δε are important factors of P (P increases with V). The polarizer is not ideal in P and lifetime, but it is satisfactory for simulation experiments. Its mechanism is that liquid crystal molecules' absorbtion is different for the two lights of bifraction. One direction of field vibrational energy is heavily absorbed, while the other is hardly absorbed at all. This device's advantages are IR operation, a large plane parallel to incident light, and an infrared plane LC modulator. Therefore it is very convenient in an LCTV-VIDIC system.