Abstract: A light shielding member formed of an annular metal base material includes a front surface, a rear surface facing away from the front surface, and an outer peripheral surface connecting the front and rear surfaces in an outer periphery of the light shielding member. The outer peripheral surface includes a ridge that is protruded outward furthest therein in a radial direction of the light shielding member, in a cross section that is parallel to a plane perpendicular to the front surface.

Abstract: A light shielding plate includes a front surface located on a light incident side, a rear surface opposite to the front surface, and a hole passing through the light shielding plate between the front surface and the rear surface. The hole has a first hole portion and a second hole portion connected to the first hole portion at an intermediate opening thereof. The first hole portion extends from a rear surface opening on the rear surface to the intermediate opening and is shaped so as to taper from the rear surface toward the front surface. The second hole portion extends from a front surface opening on the front surface to the intermediate opening and is shaped so as to taper from the front surface toward the rear surface. The front surface opening is larger than the rear surface opening. The intermediate opening has a circularity of 3 ?m or less.

Abstract: A light shielding member formed of an annular metal base material includes a front surface, a rear surface facing away from the front surface, and an outer peripheral surface connecting the front and rear surfaces in an outer periphery of the light shielding member. The outer peripheral surface includes a ridge that is protruded outward furthest therein in a radial direction of the light shielding member, in a cross section that is parallel to a plane perpendicular to the front surface.

Abstract: A.DELTA..sup.1 - tetrahydrophthalic anhydride is reacted with an amine in the presence of lower fatty acid. Alternatively N-(4-hydroxyphenyl)-.DELTA..sup.1 -tetrahydrophthalimide or a salt thereof is reacted with an aralkyl halide. A N-substituted-.DELTA..sup.1 -tetrahydrophthalimide compound having herbicidal activity is produced. This compound has the formula ##EQU1## wherein R' is naphthyl; phenyl; phenyl substituted by 1-3 substituents selected from the group consisting of halogen, nitro, cyano, thiocyano, carboxyl, haloalkyl, lower alkyl and alkylthio; --CH.sub.2 Y wherein Y is phenyl, naphthyl or phenyl substituted by 1-5 substituents selected from the group consisting of halogen, nitro, lower alkyl and lower alkoxyl; or ##SPC1##Wherein Z is phenyl, naphthyl, or phenyl substituted by at least one substituent selected from the group consisting of halogen, nitro, lower alkyl and lower alkoxyl.