Measurement of coating thickness non-uniformity of photosensitive film in production process

In photo material industry, the check of quality about surface of photosensitive layer is very important. If there is uneven thickness failure in photo layer, it may cause a shadow or a stripe. In these days, a laser deposit analyzer is available that lights laser spot on material and measures reflection. It has reliability for detecting a pinhole or other sharp deposit like bull's eye, but it is difficult to detect uneven thickness in photo layer. In this report, a method of analyzing uneven thickness like stripes on photo layer or other deposits is described. We tested many methods of photo surface inspection. Finally, we chose light reflection method and constructed a test system of photo layer surface inspection equipment that can be built in or added on to photo material factory machines. The constructed equipment proved to be less sensitive to mechanical noises and low cost of building and running.