A preferred OPTICAL BLACK ionic anodize process of the present invention applies a porous anodic oxide coating to a component part in a standard sulfuric acid anodizing bath (with or without organic additives). A modified alternating electric current is then applied to the porous oxide coating to remove...http://www.google.com.au/patents/US6414754?utm_source=gb-gplus-sharePatent US6414754 - Method and apparatus for suppressing stray light in particle detectors
