Greenblum & Bernstein P.L.C.
Method of making an aperture plate for a multibeam pattern drawing apparatus
 For an aperture plate to be used to form dot images of a two dimensional aperture pattern by projection through an imaging optical system in a normal direction, a pattern of markings in ideal positions is projected through an imaging optical system in the reverse direction to normal imaging operations. The image of the pattern is recorded at the position of the aperture plate, and the recorded image is used as a guide to form corrected apertures in the aperture plate. Accordingly, locational errors of the dot images in the normal direction are corrected when the corrected aperture plate is used. 
Asahi Kogaku Kogyo Kabushiki Kaisha
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G03F B41J B41J B41J
inventional inventional inventional inventional
Tetsuya Shinichi Tamihiro Satoru Takashi Koichi
Nakamura Suzuki Miyoshi Tachihara Okuyama Maruyama