US Government As Represented by the Secretary of the Army

Bernard J Rod

Steven C Tidrow

Daniel M Potrepka

Frank J Crowne

Judith T McCullen

Bohdan J Dobriansky

Theodore V Blomquist

A detector for electromagnetic radiation such as millimeter wave and infrared employs a ring-shaped ferroelectric element having a temperature affected by an absorber for the radiation. The dielectric constant of the ferroelectric material is a strong function of the temperature near its Curie temperature. The resonant frequency of the ferroelectric element is detected by applying a swept-frequency signal to the circuit and detecting the frequency which enhances the energy of the pulse. A two-dimensional camera for the radiation employs a two-dimensional array of these ferroelectric resonant circuits and a system for rapidly interrogating their resonant frequencies on a sequential basis.

Ferroelectric radiation detector employing frequency modulated readout

A shadow mask for sputtering is formed from a single crystal silicon wafer which is mechanically and chemically polished to produce top and bottom surfaces which are substantially flat and parallel to one another. The wafer is provided with one or more pyramidal etch pits which are arranged in a pattern. Each pit has a substantially square cross-section on the top surface, and a smaller substantially square cross-section on the bottom surface to produce an aperture in the wafer. In use, the wafer is clamped against a flat substrate with its apertures opening toward the evaporant beam. After use, the deposited species may be cleaned from the wafer using suitable etchants which render the wafer unharmed, and therefore reusable.

Silicon shadow mask

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Potomac, MD, United States of America

Bernard J Rod