Single‐polarizer reflective twisted nematics

— A general expression for the reflectance of a single‐polariser twisted‐nematic device is given. From this, solutions of liquid‐crystal parameters that will convert linear‐to‐circular (L‐C) and linear‐to‐linear (L‐L) polarizations are derived. A comparison of the field behavior for some normally black and normally white devices made from the lower Δ nd /λ solutions of the L‐C and L‐L are presented. The effect of doping on normally white devices is considered.