Abstract: A process for producing a micro Fresnel lens comprising the following steps: applying a photoresist coat to a smooth-surfaced substrate such as a glass, plastic or metal plate; exposing the resist cost to actinic radiation such as an electron beam, laser beam or UV rays; developing the exposed coat to form a resist pattern duplicating concentric rings for the desired micro Fresnel lens; forming an electrode element on the resist pattern by depositing a conductive metal such as silver or nickel by sputtering or evaporation; forming a nickel layer on the conductive metal electrode element by depositing metallic nickel or a nickel compound through electroforming wherein the pattern of the concentric rings is transferred onto the nickel layer with the conductive metal being used as an electrode; forming a nickel stamper by peeling the nickel layer from both the electrode and the substrate; and forming a micro Fresnel lens on the nickel stamper by either the photopolymerization or injection method of duplication.

Abstract: A pickup system for an optical disc reading/recording apparatus in which a micro Fresnel lens, formed with concentric circular gratings, is used in place of an optical element, such as an objective lens, for focussing and collimating light beams from a semiconductor light source. The pickup system so formed is light in weight, easily miniaturized, and inexpensive to manufacture. The micro Fresnel lens can be formed as an integral unit with the semiconductor laser by mounting the lens in a window of the case of the semiconductor laser.

Abstract: A process for producing a micro Fresnel lens comprises the following steps: moving either a substrate coated with a resist layer for providing the micro Fresnel lens or a source of actinic radiation such as electron beam for exposing the resist layer relative to each other in a fixed direction; scanning linearly the resist coat with the actinic radiation in a direction perpendicular to the direction of the relative movement; during the scanning operation, performing exposure to the actinic radiation or interrupting or overlapping the application of the actinic radiation so as to form a latent image in an area corresponding to the grooved surface of the micro Fresnel lens within a predetermined width; repeating the above procedures in a direction perpendicular to that of the relative movement of the substrate and the source of actinic radiation; and developing the exposed resist layer to provide a micro Fresnel lens having the desired grooved surface.

Abstract: A method of fabricating an integrated semiconductor circuit device having a plurality of layers of circuit patterns, comprising forming the circuit pattern of at least one of the above mentioned layers by a direct exposure method using an electron beam, and forming the circuit pattern of at least one of the remaining layers by a light exposure method using a photomask.

Abstract: A magnetoelectric transducer includes a high mobility semiconductor thin film formed on a layer such as an alumina film. Processing to form the device is improved by simultaneous patterning of the semiconductor thin film and an electrode layer. Improved resistance to the effects of heat are obtained by using a highly heat conductive substrate. Integrally with the substrate there may be formed an element such as a series resistor for temperature compensation of the magnetic sensor of the transducer.

Abstract: A magnetoelectric transducer having a substrate of magnetic or non-magnetic material is improved by providing a thin film of crystalline semiconductor In.sub.1-x Ga.sub.x Sb (0<x.ltoreq.0.2) on the substrate either directly or through a metal or semiconductor oxide film.