Photovoltaic-ferroelectric correlation devices
AssigneeThe United States of America as represented by the Secretary of the Army
InventorPhilip S. Brody
Life of this patent
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Abstract
A photovoltaic-ferroelectric correlation device for both optical pattern relation and signal correlation. A remanent polarization pattern is induced in a photovoltaic-ferroelectric layer, and when irradiated with an illumination pattern, the photocurrent produced at each point of the layer is proportional to the product of the remanent polarization at that point and the illumination at that point. The sum of the point currents produced, or the short circuit photocurrent of the device, is proportional to the integral of the products, which is the correlation of the two patterns.
Claims12
A photovoltaic-ferroelectric correlation device comprising,
- a layer of photovoltaic-ferroelectric material,
- means for applying a spatially varying voltage pattern to said layer of material to induce a remanent polarization pattern therein which corresponds to said voltage pattern,
- means for illuminating said remanently polarized layer with an illumination pattern having spatial variations in intensity,
- means for collecting the photocurrent induced at each point on the surface of said photovoltaic-ferroelectric layer as a result of said illumination, which photocurrent is proportional to both the remanent polarization and the intensity of the incident illumination, and
- means for providing an indication of the total current induced, which indication corresponds to the correlation of said two patterns.
A photovoltaic-ferroelectric correlation device for correlating patterns, comprising,
- a layer of photovoltaic-ferroelectric material and a layer of photoconductive material sandwiched between two electrodes, said sandwich having an array of cavities therein,
- means for inducing a remanent polarization pattern in said array of cavities comprising means for applying a voltage across said sandwich and first illumination means for illuminating said cavities with a first illumination pattern while said voltage is applied,
- second illumination means for illuminating said cavities after said voltage is removed with a second pattern to be correlated with said first pattern,
- means for collecting the photocurrent induced in each cavity which photocurrent is proportional to the product of said remanent polarization and the intensity of said second illumination, and
- means for providing an indication of the total current from all of said cavities, which is proportional to the correlation of said two patterns.
Dependencies are inferred from the claim text.