CPC H04N 23/55 (2023.01) [C23C 16/30 (2013.01); C23F 1/02 (2013.01); G02B 1/113 (2013.01); G02B 5/005 (2013.01); H04N 23/50 (2023.01); H04N 23/51 (2023.01)] | 11 Claims |
1. A light shielding plate made of metal, comprising:
a front surface located on a light incident side;
a rear surface facing away from the front surface; and
an aperture penetrating through the front surface and the rear surface, wherein
the aperture includes a first aperture portion and a second aperture portion connected to the first aperture portion via a central opening, the first aperture portion extending from a rear opening in the rear surface toward the central opening and having a shape tapered from the rear surface toward the front surface, the second aperture portion extending from a front opening in the front surface toward the central opening and having a shape tapered from the front surface toward the rear surface, the front opening being larger than the rear opening; and
when an image of an edge of the central opening is captured in a radial direction thereof by bringing the edge into focus under imaging conditions where a depth of field is 0.4 μm, a maximum focusable length of the light shielding plate that can be in focus in a thickness direction thereof is 7.0 μm or less.
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