A light valve of the present invention comprises an oblique cut single crystal plate of strontium barium niobate (SBN), which is placed in a plane vertical to a light transmission; a plurality of transparent strip electrodes which are placed, at right intersections with each other, on the front and back surfaces of the plate; means for generating an electric field within the single crystal, in parallel with a light transmission direction, in a given region of the plate to be addressed by selectively providing an electric potential to these electrodes; an SBN single crystal plate of the same thickness and orientation, which is juxtaposed with the single crystal plate so that the optical axes of them may be at right angles to each other; and polarizers which are each provided in positions before and behind these both single crystal plates so that light polarization plane thereof may be at right angles to each other. In the light valve of the present invention, the SBN single crystal plate is operated as a longitudinal operation mode electro-optic material, and the birefringence shows a non-linear change and a hysteresis loop by a change in an applied electric field. The residual birefringence is used as an optical read/write memory. Also, a threshold of abrupt non-linear change region of the birefringence hysteresis loop may be used advantageously for selecting a voltage applied to the electrode, whereby cross-talk in addressing is avoided.
In an electro-optical light shutter device using a solid-solution ceramic material for alternate transmission and interception of light, a first voltage is applied to the solid-solution ceramic material in the operating (open) position of the shutter, and a second voltage of polarity opposite to that of the first voltage and having an absolute value smaller than that of the first voltage is applied to the solid-solution ceramic material in the non-operating (closed) position of the shutter. The solid-solution ceramic material has a composition in which a ferroelectric phase and a non-ferroelectric phase adjoin each other through a morphotropic phase boundary.
A scanning apparatus for an electrophoretic matrix display panel, has a horizontal (X-line) electrode driving circuit to provide a selecting pulse, a vertical (Y-line) electrode driving circuit to provide a data pulse, and an information signal supply means. An electric field is imposed across cells of an electrophoretic suspension layer to change the optical reflective property of the cells in a predetermined sequence after a pause interval by the horizontal and vertical electrode driving circuits. This causes operation of the display panel without cross effect.
A piezoelectric material includes a polycrystalline piezoelectric compound having a component composition defined as Sr.sub.2-x Ca.sub.x NaNb.sub.5 O.sub.15, where x=0.05 to 0.35, and at least one rare earth oxide compound selected from the group consisting of Y.sub.2 O.sub.3, La.sub.2 O.sub.3, Dy.sub.2 O.sub.3, Nd.sub.2 O.sub.3, Yb.sub.2 O.sub.3, Sm.sub.2 O.sub.3, Er.sub.2 O.sub.3, Gd.sub.2 O.sub.3 and Pr.sub.6 O.sub.11 to be added to the piezoelectric compound by 0.5 to 3.0 wt %. Moreover, a method of manufacturing the piezoelectric material includes blending ceramic materials, synthesizing, milling, pressing and sintering processes. In the synthesizing process, calcining is conducted at a temperature in a range from 1,050.degree. C. to 1,150.degree. C. for 2 to 12 hours in the atmosphere. And the sintering process includes first firing at temperature in a range from 1,180.degree. C. to 1,270.degree. C. for 4 to 8 hours in the atmosphere, and second firing at a temperature in a range from 1,370.degree. C. to 1,400.degree. C. for 10 to 75 hours in the atmosphere.
The present invention relates to photo excitable ferroelectric optical memory system designed to store, erase, and display light traces. In accordance with the invention, there is provided a system wherein a photo-ferroelectric plate is placed between a polarizer and a polarization analyzer. Under the combined action of a recording radiation and an external electric field, a photo induced electric is formed in the illuminated zones of the plate. Erasure is obtained by re-illuminating the plate without applying any external field. The optical display is achieved by means of an electric read-out field.
A spatial light modulator having a lattice of microgrooves formed on the surface of the silicon photodiode nearest the electro-optic cyrstal to prevent lateral charge transfer at this surface.
