Measuring and testing – Instrument proving or calibrating – Speed – velocity – or acceleration
Reexamination Certificate
2001-03-30
2003-11-04
Noland, Thomas P. (Department: 2856)
Measuring and testing
Instrument proving or calibrating
Speed, velocity, or acceleration
C073S001770
Reexamination Certificate
active
06640610
ABSTRACT:
FIELD OF INVENTION
This invention relates to an automatic integrated mechanical and electrical angular motion detector test system.
BACKGROUND OF INVENTION
Conventional integrated circuit (IC) device handlers automatically feed IC devices to a contactor which makes electrical interconnection between the IC device and a tester. After the tester runs a series of tests on that IC device, the device is removed from the contactor and output from the handler to one of a number of bins depending on whether it passed the test or failed it. There may be a number of future bins for classifying different types of failures. These systems have high throughput typically from 500-8000 devices/hour with little or no human intervention.
Separately, gyroscope testers for conventional strategic and tactical gyroscopes typically employ a large rate table with fixtures including temperature chambers for testing a gyroscope. The gyroscopes are manually placed and installed before testing and are manually removed after testing. The testing involves performing electrical testing while the gyroscope is being rotated in order to insure proper performance under actual operating conditions. A typical test time is several minutes to a few hours per gyroscope. These gyroscopes are relatively heavy and large, e.g. strategic gyroscopes—two inch diameter, four inches long; tactical gyroscopes—one inch diameter, two inches long. Typically a number of these gyroscopes are tested at one time to produce even a reasonable throughput. The tables are large and powerful to obtain the necessary rotational speed and accuracy with the gyroscopes loaded on board. Further, these tables must be precisely controlled in order to insure the reliability of the test data of these precision gyroscopes. The table must rotate at significant speed for a substantial period of time with very little fluctuation in the rotational speed.
More recently, micromachining techniques have produced extremely small, lightweight micromachined gyroscopes. See U.S. Pat. No. 6,122,961. These gyroscopes, too, must be tested. However, the more commercial nature of their market requires precision testing but with much higher throughput and less human intervention. The rate tables so appropriate for the larger gyroscopes are excessive and too slow for processing these micromachined gyroscopes.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide an improved automatic, integrated mechanical and electrical angular motion detector test system.
It is a further object of this invention to provide such an angular motion detector test system which is smaller, lighter, and simpler.
It is a further object of this invention to provide such an angular motion detector test system which has a higher throughput.
It is a further object of this invention to provide such an angular motion detector test system which is faster, more efficient, more accurate and more reliable.
It is a further object of this invention to provide such an angular motion detector test system which measures the electrical parameters of a gyroscope while it is being rotated to obtain performance data under various operating conditions.
It is a further object of this invention to provide such an angular motion detector test system which enables the mechanical and electrical testing of an IC gyroscope.
It is a further object of this invention to provide such an angular motion detector test system which provides a sinusoidal drive to rotate the gyroscope under test.
The invention results from the realization that a smaller, simpler, lightweight, automated, angular motion detector test system with high throughput can be achieved using a test fixture for holding a device to be tested, a handler for feeding devices to be tested to the test fixture, rotating the test fixture with a device to be tested and electrically testing the device while it is being rotated, and the further realization that micromachined angular motion detectors can be handled and fed to the test fixture as common IC's and then rotated in a stepwise fashion or by oscillation as with a galvanometer to obtain performance data from the electrical circuits of the device while it is being rotated.
This invention features an automatic integrated mechanical and electrical angular motion detector test system. There is a test fixture for holding an angular motion detector to be mechanically and electrically tested and a handler subsystem for feeding an angular motion detector to the test fixture. A motor has a rotatable shaft attached to the test fixture for rotating it and the angular motion detector that it holds and an electrical tester tests the angular motion detector while it is rotating.
In a preferred embodiment the test fixture may include a seat for supporting the angular motion detector in the test fixture. There may be clamp for urging an angular motion detector against the seat. There may be a vacuum chuck for holding and sensing the presence of an angular motion detector to be tested. There may be a contactor having at least one set of gripping contacts for engaging an angular motion to be tested. The clamp may include a lever and an actuator for driving the lever to operate the clamp. The contactor may include a lever and an actuator for driving the lever to operate the gripping contacts. The motor may include an oscillator motor. The motor may provide a sinusoidal output motion to the test fixture. The motor may include a stepper motor or galvanometer. The angular motion detector may be an angular accelerometer or a gyroscope. The gyroscope may be an integrated circuit chip and it may be micromachined.
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Beucler Brian G.
Hanle Christopher F.
Lueth, II Richard A.
Malone Robert E.
O'Reilly Robert P.
Analog Devices Inc.
Iandiorio & Teska
Noland Thomas P.
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