Laser-Based System for Measuring and Analyzing Vibrations

Unlike accelerometers, noncontact sensors do not alter dynamics of lightweight objects.

A system for noncontact measurement and analysis of vibrations of an electronic circuit board or a similar lightweight, nominally flat, rectangular object has been developed. This system, which utilizes laser displacement sensors, offers an important advantage over a traditional vibration-measurement system that utilizes accelerometers mounted on the vibrating object under test: Accelerometers are not suitable for vibration testing of a lightweight object because they contribute mass to the object and thereby alter the dynamic behavior of the object and thereby, further, give rise to errors in vibration-test data. In contrast, the laser displacement sensors in the present noncontact system do not contribute mass and do not significantly alter the dynamics.