Mca Disco-vision, Inc.

Other

Discovision Associates

Lawrence S Canino

James E Elliott

Donald W Stoner

A chip tester for testing microelectronic circuit chips. The tester is capable of testing a variety of chip types in a single socket, including chips having different circuit functions, different pin configurations, and different number of pins. Tests are performed without any preliminary tester setup steps other than placing the chip to be tested into the test socket. The tester applies input voltages and output loads and monitors input and output signals for a first possible chip type, and upon failing to meet expected input/output measurement conditions, applies input voltages and output loads and monitors input and output signals for a second possible chip type. The process is repeated and continues until the monitored inputs/outputs for the chip under test meet the expected input/output measurement conditions, at which time a display device indicates that the chip under test is operational and, preferably, displays the chip type. The tester then repeatedly applies the test procedure only for the chip type being tested, the latter test procedure repeating indefinitely. The inputs and outputs continue to be monitored, and should an error appear in the measurements during any of the repeated tests, a count is made of the number of errors detected, and the count of the number of errors is displayed.

Chip tester

A method and means for measuring and/or determining characteristics of a material by analyzing the characteristics of an energy beam incident upon and affected by the sample. Polarized radiant energy reflected and/or transmitted by the material sample is analyzed to infer optical properties such as index of refraction, and physical properties such as material thickness. The invention is not subject to the disadvantages of prior art measuring systems, in that absolute detected light values are not used, measurement of varying wavelengths of light are not necessary, surface defects contribute a balanced effect in the calculations so as to effectively cancel out, highly accurate angular measuring devices are not needed, precision nulling instruments are avoided, system parameter drift effects upon the measurement is avoided, inter alia. According to the invention, a method and means are provided for measuring an optical property of a thin material sample having a transmission efficiency of greater than zero for an impinging beam of radiant energy. A source beam of radiant energy at a given wavelength and of varying polarization direction is provided, and the polarization-varying beam is directed onto an entry surface of the thin material sample at a predetermined angle with respect thereto. The beam leaving the sample is analyzed to determine the relative amplitudes of first and second polarized components thereof. The optical property of the sample is determined from a mathematical model equating the optical property to a relationship between said wavelength of the source beam, the predetermined angle, and the results of detecting and analyzing the beam exiting the sample.

Method and apparatus for measuring properties of thin materials using

A spindle assembly is provided for rotatably supporting and driving a video information disc in a video recorder-playback machine. The spindle assembly comprises a vertically extending journal having a generally truncated conical shape and supported for rotation in an inverted position within a complementary shaped spindle housing. Pressurized air is supplied through a plurality of slotted flow paths to the support interface between the journal and the spindle housing for supporting the journal for relatively high speed rotation on a cushion of air.

Spindle assembly for a video recorder-playback machine

A video disc player assembly is described employing a fixed base member with a pair of fixed rails, and a movable carriage member employing a pair of linear bearing assemblies in engagement with said rails. A stabilization plate is mounted on the movable carriage for movement therewith. A motor and spindle assembly is mounted on the stabilization plate. A portion of the motor and spindle assembly extends through axially aligned apertures in the stabilization plate and carriage and carries a videodisc mounting surface coplanar with the stabilization plate. A centering means is provided to accurately center the disc about the spindle. A releasable clamp rigidly engages the spindle and holds the videodisc against the mounting surface parallel to the stabilization plate. A motor and spindle are mounted on the carriage for rotary driving of the video disc, a centering means is provided to accurately center the disc about the spindle, and a stabilization plate is provided adjacent and parallel to the rotating disc.

Video disc player

A servo control system for maintaining an information detection device, such as a light beam, centered on a moving information track, such as a spiral recording track on a video disc. The system of the invention includes a dither signal generator, a bandpass filter for deriving an intermediate signal indicative of the effect of dither on the detected signal derived from the information track, and switching circuitry for deriving an error signal from the intermediate signal and the polarity of the dither signal. In one embodiment of the invention, the switching circuitry includes an inverter, and a switch for selecting either the intermediate signal or the inverted intermediate signal, in accordance with the polarity of the dither signal. The error signal thus derived is low-pass filtered and has a positive value when the center position of the beam moves to one side of the track, and a negative value when the center position of the beam moves to the other side. In an alternate embodiment, a pulse generator provides two trains of pulses occurring at the positive and negative peaks of the dither signal, respectively, and the pulse trains are employed to control two sample-to-hold circuits, respectively supplied with the intermediate signal and its inverse.

Dithered center tracking system

A transducer head assembly supported above a surface has the spacing of its transducer head from the surface maintained at a predetermined value by a pressure-sensitive regulator which responds to changes in fluid flow pressure resulting from spacing changes to correct variations from the predetermined spacing. The assembly includes a pair of expandable chambers which are coupled to each other through a fluid restrictor and which carry the transducer head, the expandable chambers being sensitive to pressure changes and causing the transducer head to move toward and away from the surface in response to such changes to correct the fluid flow pressure.

Growing community of inventors

Torrance, CA, United States of America

Lawrence S Canino