METHOD FOR CONTROLLING AN OPTICAL CHARACTERISTIC OF A MATERIAL AND TO AN ANALOGUE IMAGER FOR CARRYING OUT SAID METHOD

摘要

1496576 Matrix displays COMMISSARIAT A L'ENERGIE ATOMIQUE 27 Jan 1975 [6 Feb 1974] 3483/75 Heading G5C [Also in Division G2] To control an optical characteristic of a material between two electrodes, signals of the same frequency and with the same arithmetic mean value are applied to each electrode and the relative phase thereof is varied and assumes a value between 0 and # for at least part of the. time. The preferred embodiments relate to control of the birefringence of a nematic liquid layer (MBBA), which is proportional to the square of the applied potential difference, using rectangular or sinusoidal signals, but the optical characteristic may also be opacity, refractive index, transparency, absorption, diffusion, diffraction, rotatory power, or intensity of reflection, and may be varied in response to magnetic, thermal or electronic constraints, produced in response to the electrical signals. Also particularly referred to is the use of electrical heating to displace the absorption band of CdS, and the electrostatic deformation of a reflecting membrane. The relative phase may be varied in steps, or continuously, such that the optical characteristic is generally proportional to the amplitude of an input control signal. In a coincidence addressed X-Y array, column electrodes are scanned with a reference alternating signal, and the line electrodes are addressed in parallel with signals derived from the reference signal by phase shifting.