Acoustic Substrate Tester
Original Publication Date: 1988-Jul-01
Included in the Prior Art Database: 2005-Feb-15
This tester provides an automatic check of pinned substrates for hidden defects, such as internal cracks, and operates in automated production lines to reject any substrate having such a defect. (Image Omitted) Fig. 1 shows a substrate tester in which individual substrates 10 slide along an inclined track 11 in which they may vibrate freely when striking a bump 12. Actually, it is the pins 13 that are extending downwardly from the substrate 10 that encounter the bump 12, and this causes the substrate 10 to vibrate in resonance. The resonant vibrations produced by the substrate 10 are picked up by a microphone 14 that is connected to a circuit which amplifies the vibration frequencies. A "good" substrate has a distinctive frequency, and it is distinguishable from the vibration frequencies of a substrate that has defects.