Abstract: An optical device manufacturing method includes a step of accumulating an optical device inorganic material on a stamper by use of a vacuum thin-film growing method, and a step of removing the accumulated material from the stamper, thereby producing an optical device.

Abstract: In a machine tool such as a machining center or the like having an automatic tool changing apparatus, the tool holders adapted to respectively hold the tools provided for the automatic tool change are equipped with transmitters for transmitting signals indicative of tool data including the tool discrimination data of the tools. The receiver which receives the transmitted signals from the transmitters is attached to the machine tool. When a transmitter approaches the receiver, the transmitted data is received by the receiver. The kind and other data concerning the tool stored in the tool holder to which a transmitter is attached can be discriminated by the control unit of the machine tool on the basis of the received data.

Abstract: This switch device for detecting an object comprises a transducer for emitting and receiving ultrasonic signals to and from an object, a transmitter for driving the transducer, a receiver for receiving a signal from the transducer, a gate for detecting a short-distant object, a gate for detecting a long-distant object, and a circuit for setting the timings of the gates in accordance with the detecting ranges of the object.