A new approach method to improve the brightness uniformity in color display tubes

In order to meet the requirements and expectations from customers, it is necessary to improve continuously the quality of products. For color display tubes, the brightness uniformity is one of main concerns of customers and end users. We are starting a new approach to improve the brightness uniformity. The causes of influencing the brightness uniformity include exposure correction lens (landing), exposure filter, photographic process, shadow mask design, etc. The design of the filter, which corrects the light intensity distribution in the exposure system, is the most important. We can measure 192 points for tubes' brightness distribution and black matrix hole size distribution within a certain time. From the measurement results, a new correcting filter to improve the brightness uniformity can be made by our design model. The sizes of the black matrix from the center to the edge are made almost the same as the target. Better brightness uniformity in a color display tube is realized.