Nipkov Disc

The rotating Nipkow disk is the key technology that makes the direct view microscopes possible. Although the disk is conceptually based on Nipkow's original design for a mechanically scanned television, it was modified by Petran and Hadravsky to improve the light efficiency and increase the number of lines in the image. A single modulated light source was used in the original application of the Nipkow disk, so that only one pinhole of a set arranged along a rotating single spiral was illuminated at a time. For the microscopy application, because they had an extended light source and a CCD camera or the human eye as the receiver, Petran and Hadravsky could use parallel processing. Their disk contained many thousands of pinholes arranged in multiple interleaved spirals. Several hundred pinholes at a time were simultaneously illuminated.