International Business Machines Corporation

Thomas H Di Stefano

Arnold Halperin

Halil Burhan Bakoglu

Robert Sadofsky

An optical floppy disk system is described in which the optical disk is enclosed in a flexible housing which is optically transparent. Both the optical disk and its protective housing can be made at very low cost from inexpensive materials. The disk is enclosed within the protective housing and the housing and disk rotate as a unit during operation. The protective housing does not adversely affect the optics of the system.

Sealed encapsulation for floppy disk using centrifugal force to flatten

This optical sensor has cylindrical symmetry and is comprised of a semiconductor light source/light detector combination and an optical element comprising a single lens, where the sensor is particularly suitable for uses in accurate position detection in data recording systems. In a preferred embodiment, the light source is a forward-biased p-n junction, while the light detector is a reverse-biased p-n junction located below the light source and coaxial therewith. Light from the source is directed to a point on a data recording medium and the light reflected therefrom passes through the light source to the light detecting junction. The ac signal corresponding to the reflected light is an indication of the position of the recording head with respect to the data storage medium.

Optical sensor for servo position control

The tester and method for nondestructively detecting nonlinearity faults in conductors includes the application of a composite AC and DC drive signal to the device under test in such manner that nonlinearities in the device under test produce fault signals including second harmonics, due to local changes of resistance caused by ohmic heating. Electronic filters are used to select out and amplify the second harmonic only, eliminating the direct current and fundamental frequency components of the initial test pulse, plus third and subsequent harmonics. The filtered second harmonic signals from the device under test are then phase-compared to a phase-shifted second harmonic signal produced by a frequency doubler from the test signal generator oscillator to cancel out the second harmonic signals from the good conductor; the remaining phase anomaly signals control a threshold detector remaining to provide fault indication.

Growing community of inventors

Bronxville, NY, United States of America

Thomas H Di Stefano