The Standard Oil Company

Stemcor Corporation

Ois Optical Imaging Systems, Inc.

Miroslav Ondris

Marty A Pichler

Richard E Brownfield

Allen A Endres

A high density planar array of substrate-supported, thin film diodes constituting photoresponsive semiconductor elements is placed between a document to be read and a light source for illuminating the document. The document is illuminated by the light source via windows in the array, reflected light from the document impinging on the photoresponsive elements constituted by the diodes which are electronically interrogated to provide a signal which is indicative of image information on the document. The light source directly illuminates small portions of each diode to establish a discharge or bias current that makes the array more sensitive and responsive. The high density diodes of the array can be formed in a manner that minimizes leakage current between adjacent diodes.

Light biased photoresponsive array having low conductivity regions

A method and means for the electronic processing of an analog signal generated in a series addressed diode array to produce a digital signal indicative of the illumination of the photodiodes in the array is disclosed. A voltage ramp is applied to the array and the resulting current steps converted to a voltage signal. The voltage signal is differentiated and the resulting pulses are digitized to provide the illumination state of the photodiodes in the array. Alternately, the voltage signal is integrated in a series of windows. The results of each previous integration is substrated from the most current integration, producing a series of pulses that are digitized to provide the illumination state of the array. The processing may be synchronized by either dividing the sweep interval into evenly spaced intervals, by differentiating the voltage signal and detecting the derivative exceeding a threshold, or differentiating the voltage signal twice and detecting zero-crossings in the resulting signal. The voltage ramp may be made to increase in slope with time to help ensure that the addressing diodes begin conducting at equal time intervals.

Method and means for processing an analog signal from a diode array

A method of electrodepositing a doped compound semiconductor film including tellurium and a metal selected from Group IIB of the Period Table of Elements by adding an effective concentration of dopant ions to the electrolyte bath. Cadmium telluride, mercury cadmium telluride and zinc cadmium telluride may be doped with copper, silver and gold. The conductivity type of the electrodeposited doped layers may be changed by a heat treatment. Thin film photovoltaic cells incorporating the doped layer to form a heterojunction with a semiconductor layer of the opposite conductivity type show substantial improvements in open circuit voltage, fill factor and efficiency over similar devices employing undoped electrodeposited layers.

Electrodeposited doped II-VI semiconductor films and devices

Light biased photoresponsive array

An array for sensing the relative intensity of electromagnetic radiation at a plurality of locations employs a network of photodiodes and non-photoresponsive diodes. A first terminal of each photodiode, e.g. the anode, is electrically connected to a common point which is one terminal of the array. The non-photoresponsive diodes are connected in like-polarity series. The second terminal of each photoresponsive diode is connected to a different connection of non-photoresponsive diodes in the string. The array is scanned with a voltage ramp signal and each change in current flow indicates an illuminated diode. The particular voltage at which current flow changes discloses which photodiode is illuminated. Embodiments of the novel array can be made monolithically without a significant number of conductor cross overs. Monolithic embodiments of the array may be conveniently formed from monocrystalline semiconductors and thin films of amorphous and polycrystalline semiconductors such as amorphous silicon and electrodeposited cadmium telluride-containing semiconductors.

Making a photoresponsive array

An array for sensing the relative intensity of electromagnetic radiation at a plurality of locations employs a network of photodiodes and non-photoresponsive diodes. A first terminal of each photodiode, e.g. the anode, is electrically connected to a common point which is one terminal of the array. The non-photoresponsive diodes are connected in like-polarity series. The second terminal of each photoresponsive diode is connected to a different connection of non-photoresponsive diodes in the string. The array is scanned with a voltage ramp signal and each change in current flow indicates an illuminated diode. The particular voltage at which current flow changes discloses which photodiode is illuminated. Embodiments of the novel array can be made monolithically without a significant number of conductor cross overs. Monolithic embodimetns of the array may be conveniently formed from monocrystalline semiconductors and thin films of amorphous and polycrystalline semiconductors such as amorphous silicon and electrodeposited cadmium telluride-containing semiconductors.

Interconnected array of photosensors for simultaneously sensing light

A three layer, photovoltaic structure having polycrystalline semiconductor layers disposed in series optically and in sequential touching contact includes a relatively wide optical bandgap energy window layer, a light-absorbing layer and a third, relatively wide bandgap energy layer that forms a minority carrier mirror with the light-absorbing layer. All three layers have different compositions so that the structure includes two heterojunctions. The light-absorbing layer and third layer are of the same conductivity type. The structure is conveniently realized using II-VI semiconductor compounds such as a cadmium sulfide or zinc sulfide window layer, a mercury cadmium telluride, cadmium telluride, zinc cadmium telluride or mercury zinc telluride light-absorbing layer and a third layer of cadmium telluride, zinc telluride, zinc cadmium telluride, mercury cadmium telluride or cadmium manganese telluride. Cadmium is present in at least two of the three layers of the novel structures. Tellurium is present in two of the three layers. Structures according to the invention may be conveniently formed by electrodeposition and may employ opaque or transparent substrates depending on the particular semiconductor materials used and their relative positions.

Growing community of inventors

Chagrin Falls, OH, United States of America

Miroslav Ondris