Surface inspection tool

摘要: A laser based inspection tool (LIT) for inspecting planar surfaces is described. In a preferred embodiment the LIT can simultaneously inspect both of disks use in disk drives. The uses mechanical lifter which moves through scan lines (i.e. perpendicular to lines) allow entire surface on each side be scanned. light reflected from routed detector converts intensity beam into an analog signal. signal sampled and digitized generate pixel data. data acquisition system sequentially stores buffer. edges are determined line while progress. mask applied direct defect detection only meaningful areas median filter derivative analysis detect deviations indicating defects.