CRT Monitor Shadowmasks
Inspection processes for the shadowmasks used on today’s high-resolution CRTs present difficult metrology challenges because of the need to make very precise measurements of the features for individual mask apertures while also maintaining uniformity across relatively large coordinate spaces representing entire screen areas.
The exact positions, sizes, and min/max distances between individual features and groups of features in the mask are critical to achieving consistent sharpness and color fidelity across the whole display area in the finished CRT. In order to meet these challenges, a metrology system must be able to hold consistent high-resolution accuracy and tight calibration across large table sizes while also providing high-speed stage travel performance to maintain acceptable throughput.
Fast measurement cycle times, sophisticated image recognition, flexible lighting capabilities, and autofocus/grid-focus functions are also critical for effective near in-line shadowmask process control inspection.