A transmissivity controlled film 12 (CrO or the like), a transmissivity reduced film 13 (Cr or the like), and a resist film 14, for instance, are sequentially formed on, e.g., a transparent substrate 11. A resist is removed from an area (an area C) where a light-transmission section is to be formed,...http://www.google.com.au/patents/US7745842?utm_source=gb-gplus-sharePatent US7745842 - Graytone mask and method thereof
