John L Tyson

US Patent:

50945289, Mar 10, 1992

Filed:

May 25, 1990

Appl. No.:

7/528474

Inventors:

John Tyson - Wayne PA
John W. Newman - Berwyn PA

Assignee:

Laser Technology, Inc. - Norristown PA

International Classification:

G01L 124

US Classification:

356 355

Abstract:

Two laterally-displaced images of a test object interfere with each other to form a shearogram. Two shearograms, taken while the object is unstressed and stressed, respectively, are compared electronically to yield a composite interference pattern. According to the invention, each shearogram is formed by the interference of pairs of distinct rays of coherent light, reflected from different points on the object. The first ray of each pair is reflected from the object, strikes a mirror spaced from the object, and is reflected from the mirror. At the same time, the second ray of each pair is reflected from the object and strikes a beam splitter positioned beside the mirror. The beam splitter directs a portion of the second ray in the same direction as the reflected first ray, and a portion of the first ray passes through the beam splitter without being reflected. Since the two rays have the same polarization angle, and are mutually parallel, the rays interfere. A detector is positioned to receive light from the beam splitter.

US Patent:

53071395, Apr 26, 1994

Filed:

Jan 15, 1992

Appl. No.:

7/820403

Inventors:

John Tyson - Wayne PA
John W. Newman - Berwyn PA

Assignee:

Laser Technology, Inc. - Norristown PA

International Classification:

G01L 124

US Classification:

356 355

Abstract:

This invention detects leaks in small, hermetically sealed packages, especially microchips or other packages of electronic circuits. The invention includes a procedure for detecting fine leaks, and a somewhat different procedure for finding gross leaks. To detect gross leaks, one places the package in a chamber, and varies the pressure in the chamber slightly. If the leak is not too big, one wall of the package, such as its lid, initially becomes deformed, but quickly returns to its original position, due to the leak. If the leak is very large, the wall of the package may not move at all. The position of the wall is monitored with an interferometer, such as an electronic shearography apparatus. The movements of the wall show whether there is a gross leak. In the fine leak test, the package is placed in the chamber and the pressure is changed substantially, thus causing the walls of the package to deform.

US Patent:

50823663, Jan 21, 1992

Filed:

Aug 30, 1990

Appl. No.:

7/574809

Inventors:

John Tyson - Wayne PA
John W. Newman - Berwyn PA

Assignee:

Laser Technology, Inc. - Norristown PA

International Classification:

G01B 902

US Classification:

356 355

Abstract:

This invention detects leaks in small, hermetically sealed packages, especially microchips or other packages of electronic circuits. The invention includes a procedure for detecting fine leaks, and a somewhat different procedure for finding gross leaks. To detect gross leaks, one places the package in a chamber, and varies the pressure in the chamber slightly. If the leak is not too big, one wall of the package, such as its lid, initially becomes deformed, but quickly returns to its original position, due to the leak. If the leak is very large, the wall of the package may not move at all. The position of the wall is monitored with an interferometer, preferably an electronic shearography apparatus. The movements of the wall show whether there is a gross leak. In the fine leak test, the package is placed in the chamber and the pressure is changed substantially, thus causing the walls of the package to deform.

US Patent:

52570886, Oct 26, 1993

Filed:

Mar 27, 1992

Appl. No.:

7/858416

Inventors:

John Tyson - Wayne PA
John W. Newman - Berwyn PA

Assignee:

Laser Technology, Inc. - Norristown PA

International Classification:

G01B 902

US Classification:

356353

Abstract:

This invention tests a vehicle, such as an aircraft, using nondestructive interferometry. An interferometer detects movements in the vehicle surface due to stress. One applies such stress by pressurizing the vehicle. In one embodiment, a hood housing the interferometer attaches to the vehicle surface with the aid of a vacuum. One can vary the pressure in the vehicle in various ways, while monitoring the interferometer for signs of defects in the structure behind the surface. The invention also includes an arrangement for substantially automating the analysis. For example, one can automatically position the interferometer according to position information received from appropriate sensors, in combination with stored information about the structure of the vehicle. One preferably uses a real-time interferometer, such as an electronic shearography camera, in the present invention. One can quickly determine the location of defects by observing fringes on a video monitor.

US Patent:

47528990, Jun 21, 1988

Filed:

Oct 23, 1985

Appl. No.:

6/790480

Inventors:

John W. Newman - Wayne PA
John Tyson - Wayne PA
Thomas Gluyas - Avalon NJ

International Classification:

G06F 1520

US Classification:

364550

Abstract:

The present invention is a system for monitoring and displaying a measured parameter in each of a series of similar modules. In one embodiment, the invention can be used to monitor a parameter or condition, such as the amount of fuel in a tank, in each of a plurality of coupled locomotives. The parameter is measured by an analog or digital sensor, the output of which is connected to a microprocessor. Each locomotive in the train has such a microprocessor, and each microprocessor is programmed in substantially the same way. The microprocessors in the several locomotives are programmed to communicate with each other, and to determine which one is in the lead locomotive, and what signals are being received from which microprocessor. The value of the measured parameters for any of the locomotives of the train can therefore be displayed by the microprocessor in the lead locomotive. The programming of the microprocessors is such that the system will work regardless of the arrangement of the locomotives.

US Patent:

50917765, Feb 25, 1992

Filed:

Nov 8, 1990

Appl. No.:

7/611889

Inventors:

John Tyson - Wayne PA

Assignee:

Laser Technology, Inc. - Norristown PA

International Classification:

H04N 718

US Classification:

358 93

Abstract:

The purpose of the present invention is to improve the quality of a video signal generated by the method of nondestructive testing known as electronic shearography. In electronic shearography, two laterally-displaced images of a test object are made to interfere, and the interference pattern is stored. Another such interference pattern is obtained while the object is stressed. The two patterns are compared by computer, such as by subtracting one pattern from the other, and the resulting composite pattern is displayed on a video monitor or equivalent. According to the present invention, the subtracted signal is connected to a rectifier circuit which causes both positive-going and negative-going variations in the video signal to become positive-going variations. Thus, any changes in the intensity of the signal, due to phase changes resulting from deformation of the object, are displayed as increases in brightness of a pixel on the final display. If a point on the object has not moved due to the applied stress, the pixels representing that point remain dark.