INTEGRATED PHOTO-RESPONSIVE METAL OXIDE

SEMICONDUCTOR CIRCUIT

NASA Case No. GSC-12,782-1

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Inventor: Murzban D. Jhabvala, et al. Goddard Space Flight Center

An infrared photo-responsive element (R) is monolithically integrated into a source follower circuit of a metal oxide semiconductor device (10) by depositing a layer of a lead chalcogenide as a photo-resistive element forming an ohmic bridge between two metallization strips (26, 28) serving as electrodes of the circuit. Voltage from the circuit varies in response to illumination of the layer by infrared radiation.

A high voltage isolation transformer is provided with primary and secondary coils separated by discrete electrostatic shields from the surfaces of insulating spools on which the coils are wound. The electrostatic shields are formed by coatings of a compound having a low electrical conductivity which completely encase the coils and adhere to the surfaces of the insulating spools adjacent to the coils. Coatings of the compound also line axial bores of the spools, thereby forming electrostatic shields separating the spools from legs of a ferromagnetic core extending through the bores. The transformer is able to isolate a high constant potential applied to one of its coils, without the occurrence of sparking or corona, by coupling the coatings lining the axial bores to the ferromagnetic core and by coupling one terminal of each coil to the respective coating encasing the coil.

A high voltage power supply is formed by three discrete circuits energized by a battery to provide a plurality of concurrent output signals floating at a high output voltage on the order of several tens of kilovolts. Each circuit has a regulator stage. In the first two circuits, the regulator stages are pulse width modulated and include adjustable resistances for varying the duty cycles of pulse trains provided to corresponding oscillator stages while the third regulator stage includes an adjustable resistance for varying the amplitude of a steady signal provided to a third oscillator stage. In the first circuit, the oscillator formed by a constant current drive network and a tuned resonant network including a step-up transformer, is coupled to a second step-up transformer which, in turn, supplies an amplified sinusoidal signal to a parallel pair of complementary poled rectifying, voltage multiplier stages to generate the high output voltage. Each of the other two circuits include oscillator drive stages which, together with isolation transformers, provide output signals floating at the high output voltage.

THREE-DIMENSIONAL AND TOMOGRAPHIC IMAGING DEVICE FOR X-RAY AND GAMMA-RAY EMITTING OBJECTS

An instrument for obtaining quantitative, three-dimensional and tomographic information relating to x-ray and gamma-ray emitting objects and for the orthoscopic viewing of such objects. The output of the image intensifier is digitized by a digitizing camera in terms of position and intensity and fed into a digital computer. The computer may output quantitative information relating to the emitting object directly, such as that relating to tomograms, or provide information in analogue form when coupled with a suitable viewing device to give an orthoscopic, three-dimensional image of the object.

A method and apparatus for safely reducing abnormally high intra-ocular pressure in an eye during glaucoma surgery. A pressure regulator of the spring-biased, diaphragm type is provided with additional bias by a column of liquid. The height of the column of liquid is selected such that the pressure at a hypodermic needle connected to the output of the pressure regulator is equal to the measured pressure of the eye. The hypodermic needle can be safely inserted into the anterior chamber of the eye. Liquid is bled out of the column to reduce the bias on the diaphragm of the pressure regulator and, the output pressure of the regulator. This lowering pressure of the regulator also occurs in the eye by means of a small second bleed path provided between the pressure regulator and the hypodermic needle.