Abstract: Provided is an optical lens formed by integrally molding a lens part that is an optically effective portion and has a light incidence/emission surface, and a lens edge part that is an optically ineffective portion and has a surface thereof except the light incidence/emission surface. The lens edge part includes a non-transparent region in part or all thereof, the lens part and the lens edge part include a thermoplastic resin, and the non-transparent region in the lens edge part contains a total of 0.1-5 mass % of one or more of a black dye and a black pigment.

Abstract: A three-piece type oil ring assembly adapted to be fitted in an oil ring groove of a piston disposed within a cylinder comprises a spacer expander in the form of a gapped annulus made of section steel having substantially H-shaped radial cross section, and a pair of upper and lower side rails, each in the form of a gapped flat annulus. The spacer expander includes an axially protruding outer portion disposed on the outer circumference thereof and facing the inner surface of the cylinder, an axially protruding inner portion disposed on the inner circumference thereof and facing the innermost wall of the oil ring groove, and an axially flat connecting portion extending between the outer and inner protruding portions. The outer protruding portion has side rail supporting surfaces formed on the upper and lower ends thereof so as to be inclined toward the axially symmetrical centerline thereof along the radial direction at an acute angle with the radial direction.