Abstract

An alternate approach to the traditional contact testing method of conducting a shorts and continuity test on many of the newer families of computer cards and boards has been devised. These newly designed products do not always have fixed grids and have circuitry so dense that contact testing could prove inaccurate or damaging, depending on probe sizes and press forces. An optical tester is currently in use by IBM which is such a noncontact test system. Key advantages to this system are its grid size independence, lack of mechanical contact, and ability to identify nonconductive-type defects. Important considerations are the optical characteristics of the parts and sensing devices, including such items as contrast, uniform reflectivity, and cleanliness.

© 1981 Optical Society of America