Abstract: There is disclosed a polishing apparatus utilizing a gel material as the polishing tool, in which the gel material is rotated in the vicinity of a surface to be polished, or is given rotating and rocking motions in direct contact with the surface to be polished.

Abstract: There is disclosed a polishing apparatus utilizing a gel material as the polishing tool, in which the gel material is rotated in the vicinity of a surface to be polished, or is given rotating and rocking motions in direct contact with the surface to be polished.

Abstract: There is disclosed a polishing apparatus utilizing a gel material as the polishing tool, in which the gel material is rotated in the vicinity of a surface to be polished, or is given rotating and rocking motions in direct contact with the surface to be polished.

Abstract: A lens barrel member in which an equally divided helicoid portion is provided on the inner periphery or the outer periphery of a cylinder member forming a lens barrel, and an engaging portion engaged with another lens barrel component is provided at the end of the outer periphery of the cylinder member coaxially with the helicoid portion, the cylinder member being of a sandwich-molded structure comprising a core layer and a skin layer. Also disclosed is a method of molding such lens barrel member.

Abstract: When making a generally cylindrical article such as the barrel member of a lens barrel into a cylindrical molded article by the use of a resin material, a sandwich-molded article is formed by using a core layer resin material for the central layer of the molded article and surrounding the central layer by a skin layer resin material, the cylindrical molded article is a helicoid cylinder constituting the barrel, or a cylinder member provided with a toothed portion for receiving a drive force, or other barrel-constituting member, and the thickness of the skin layer resin material of the toothed portion of the helicoid cylinder or the barrel-constituting member is controlled.