Acoustic imaging systems

A non-destructive inspection system for forming a substantially artifact free image of a test object, which system includes

• a source of ultrasonic energy to be directed at a test object;
• a liquid crystal detector for receiving ultrasonic energy exiting the test object and providing a visual display;
• a medium for coupling the source, the test object and the detector;
• a first device for moving said source about a fixed pivot point that is substantially within said source whereby the normal to the source is caused to move through a small angle relative to the liquid crystal detector which minimizes disturbance of the medium due to movement of the source and cooperates in assuring an artifact-free image;
• and
• a second device for exciting said source so as to cause ultrasonic energy therefrom to oscillate between a pair of predetermined frequencies and scan the frequencies therebetween in a period of time sufficiently short to provide a flicker-free image;
• wherein said device for moving said source is an eccentric which includes a disk and a link system;
• wherein there is provided a housing within which the source and first device are enclosed so as to minimize coupling medium disturbance from movement of the source and which housing includes a window portion which is transparent to the ultrasonic energy so that an ultrasonic beam can be directed from the source to a position outside the housing;
• wherein the normal is caused to move through a small angle between about 2.degree. to 6.degree.;
• wherein the detector also defines a normal and said source normal and detector normal are oblique to each other and intersect at a small angle which varies between about 2.degree.and 6.degree.;
• wherein the frequency is caused to oscillate between 3.2 megahertz and 3.4 megahertz;
• and
• wherein there is provided a third device for rotating said source about an axis extending through said pivot point and normal to the source.

A non-destructive inspection system for forming a substantially artifact-free image of a test object, which system includes:

• a source of ultrasonic energy to be directed at a test object;
• a liquid crystal detector for receiving ultrasonic energy exiting the test object and providing a visual display;
• a medium for coupling the source a test object and the detector;
• a first device for moving said source about a fixed pivot that is substantially within said source, whereby the normal to the source is caused to move through a small angle relative to the liquid crystal detector;
• a second device for exciting said source so as to cause ultrasonic energy therefrom to oscillate between a pair of predetermined frequencies and scan the frequencies therebetween in a period of tine sufficiently short so as to provide a flicker free image;
• and
• a third device for rotating said source about an axis extending through said fixed pivot and normal to the source.