Laser technology is used to measure pressure or vacuum levels in paper, rubber, foil, and plastic containers by calculating lid deflection.
The laser sensor produces a pinpoint visible beam, then measures the reflected light. The angle of the laser beam is directly proportional to the distance from the lid to the sensor. This continuous signal is digitally sampled and stored in memory. A digital signal processor (DSP) performs multiple algorithms on the stored data to calculate the relative curvature of the lid. The relative curvature value is then compared to user set limits where containers with lid deflection outside these limits are rejected.