Multiple element optical memory structures using fine grain ferroelectric ceramics

Claim 2

The device recited in claim 1 in which the pair of electrodes forms an interdigitated array and in which the electrode layer forms a second interdigitated array parallel and opposite to the first interdigitated array.

Claim 3

The device recited in claim 1 in which the electrode layer on the first surface is a transparent electrically conductive film.

Claim 4

The device recited in claim 1 in which the fine grain ferroelectric plate is essentially a fine grain ferroelectric ceramic plate.

Claim 5

The device recited in claim 5 in which the ceramic is essentially a lead zirconate-lead titanate composition.

Claim 6

The device in claim 6 in which the ceramic is essentially lead zirconate-lead titanate 65/35-2 percent La.

Claim 7

The device recited in claim 6 in which the lead zirconate-lead titanate composition is doped with a rare-earth impurity.

Claim 8

An optical display system which includes: a. a fine grain ferroelectric plate whose remanent electric polarization can be switched by an applied electric field from a first state to a second state, the direction of the remanent polarization of the second state being oblique with respect to that of the first state; b. a first photoconductive layer disposed on a first major surface of the plate; c. a pair of parallel electrodes disposed on a second major surface of the plate opposite to the first major surface, said electrodes running along a first spatial direction; d. a second photoconductive layer disposed on the second major surface at least in the space between the electrodes; e. an electrode layer connected to a terminal and disposed on the first major surface; f. a source of a linearly polarized first beam of optical radiation incident upon the device so that the beam traverses the device, the first and second photoconductive layers being photoconductively responsive to a second optical beam which scans the photoconductive layers in the first direction and which beam has intensity at selected locations along the first direction sufficient to switch the polarization of the plate from the first and to the second state at the selected locations when an electric voltage is applied between the electrode layer and the pair of electrodes (while the pair is electrically connected to the same terminal) simultaneously with the scanning by the second optical beam; and g. an optical polarization analyzer upon which the beam is incident after traversing the plate in the absence of applied electric fields.

Claim 9

The system recited in claim 9 which further includes means for utilizing the first optical beam exiting from the analyzer.

Claim 10

An optical image storage system which includes: a. the system recited in claim 9; and b. means for scanning the plate with the second beam of optical radiation in the presence of an applied electric field in the plate, in order to switch the remanent electric polarization of the selected portions of the plate into the second state.