NEUTRAL DENSITY FILTER, LIGHT QUANTITY ADJUSTING DEVICE, IMAGING DEVICE, METHOD FOR MANUFACTURING NEUTRAL DENSITY FILTER, DIE CUT FORMING DEVICE FOR NEUTRAL DENSITY FILTER

摘要

PROBLEM TO BE SOLVED: To provide an optical filter which makes it possible to mass-produce neutral density filters which restrain a quantity of light passed through an optical path, in the correct position of an aperture on the optical path without variations so as to have an accurate density characteristic.;SOLUTION: The neutral density filter includes: a filter 14 which restrains a quantity of transmitted light; a base plate (aperture blade) 11 to which the filter is attached so as to face the optical path; and aligning reference faces which are formed on the base plate 11 and filter 14 and define the position where they are jointed together. The filter 14 is formed by press-forming a transparent or semi-transparent sheet into a predetermined outer shape, the sheet having a dimmer film formed on its surface. A dimmer film having two or more density areas with at least one density boundary is formed on the filter by coating. The outer shape and the aligning reference faces for the filter 14 are simultaneously formed in a position of a predetermined distance away from the density boundary, by press formation.;COPYRIGHT: (C)2010,JPO&INPIT