Robust line-scan-camera-based inspection system for ink-jet nozzle plates

There are many challenges in inspecting inkjet nozzle plates. For example, orifice sizes have gotten smaller and smaller to support smaller drop sizes. Reflective plate materials create difficulties in capturing high-contrast, top-illuminated imagery. Time constraints in production environments require high-speed image capture, feature inspection and part disposition. Current systems use 2D CCD array cameras to step and repeat inspection along the length of each plate. Step and repeat methods have inherent limitations in inspection time, focus and illumination. In response to customer needs for a more robust methodology, a line-scan camera based inspection system has been developed. This paper will describe the line-scan based inspection system including considerations for image improvement through both hardware and software modifications. System capabilities and limitations will be discussed.