Abstract: A bending tube includes a first tubular member including a first tubular opening and a second tubular member including a second tubular opening. The first tubular member includes a first end portion, a first hole, and a projection on a surface of the first end portion around a periphery of a first end of the first hole. The second tubular member includes a second end portion, a second hole, and a turning shaft projecting from a periphery of a first end of the second hole. The first end portion overlaps the second end portion and the turning shaft is seated in the first hole to connect the first tubular member to the second tubular member. The projection on the surface of the first end portion contacts a surface of the second end portion.

Abstract: A lens holding frame includes: a frame portion, a plate-shaped portion, holding portions, and auxiliary holding portions. The frame portion has a tubular shape extending along a reference axis. The plate-shaped portion overhangs inward from an inner circumferential surface of the frame portion. The holding portions protrude at sites of at least three places, which are away from each other in a circumferential direction around the reference axis on a surface of the plate-shaped portion, in a direction along the reference axis and are located on an abutting plane. The auxiliary holding portions protrude from a surface of the plate-shaped portion up to heights at which the auxiliary holding portions do not reach the abutting plane in the same direction as the holding portions.

Abstract: A lens holding frame includes: a frame portion, a plate-shaped portion, holding portions, and auxiliary holding portions. The frame portion has a tubular shape extending along a reference axis. The plate-shaped portion overhangs inward from an inner circumferential surface of the frame portion. The holding portions protrude at sites of at least three places, which are away from each other in a circumferential direction around the reference axis on a surface of the plate-shaped portion, in a direction along the reference axis and are located on an abutting plane. The auxiliary holding portions protrude from a surface of the plate-shaped portion up to heights at which the auxiliary holding portions do not reach the abutting plane in the same direction as the holding portions.

Abstract: An method for producing an optical assembly includes a first assembling step of assembling lenses from a first lens to an (n?1)-th lens (where n is an integer of 1<n?N) to a lens-holding member to assemble a pre-assembly; an optical property-measuring step of measuring optical properties of a first optical system in the pre-assembly; an optical parameter correction value-calculating step of obtaining displacement amounts from design values of the optical properties of the first optical system based on measurement results of the optical properties, and changing the optical parameters of at least the n-th lens itself from design values thereof, thereby calculating correction values of the optical parameters of the n-th lens; a lens-producing step of producing the n-th lens based on the correction values; and a second assembling step of assembling the n-th lens produced in the lens-producing step to the pre-assembly.

Abstract: A lens frame which is configured to dispose a lens on a reference axis and fix the lens, the lens frame includes an axial direction reception section configured to abut the lens in the axial direction and separated from the lens upon fixing of the lens in order to define an orientation of the lens with respect to the reference axis, an adhesive agent guide surface configured to form a gap, and an adhesive agent-blocking section formed between the adhesive agent guide surface and the axial direction reception section in the axial direction, fitted onto the side surface of the lens in the radial direction when the lens abuts the axial direction reception section, and configured to block the adhesive agent such that the adhesive agent introduced into the gap does not flow into the axial direction reception section.

Abstract: An method for producing an optical assembly includes a first assembling step of assembling lenses from a first lens to an (n?1)-th lens (where n is an integer of 1<n?N) to a lens-holding member to assemble a pre-assembly; an optical property-measuring step of measuring optical properties of a first optical system in the pre-assembly; an optical parameter correction value-calculating step of obtaining displacement amounts from design values of the optical properties of the first optical system based on measurement results of the optical properties, and changing the optical parameters of at least the n-th lens itself from design values thereof, thereby calculating correction values of the optical parameters of the n-th lens; a lens-producing step of producing the n-th lens based on the correction values; and a second assembling step of assembling the n-th lens produced in the lens-producing step to the pre-assembly.

Abstract: A first lens includes, on end surfaces of both ends in a direction along an optical axis, a first lens surface, a second lens surface, lens outer edges formed on outer peripheral sides of the first and second lens surfaces, and a lens side surface that is adjacent to the lens outer edges and serves as an outermost surface in a direction orthogonal to the optical axis. The first lens is provided so as to be mountable on a lens holding frame. In the first lens, a first abutment surface provided within one plane orthogonal to the optical axis is provided on at least one of the lens outer edges. A second projection is formed on at least one of the lens outer edges so as to protrude in the direction along the optical axis from a position closer to an inner peripheral side than the lens side surface, and the second projection has a reference cylindrical surface provided in a fixed positional relationship with the optical axis in the direction orthogonal to the optical axis.

Abstract: A mold set includes: a first mold and a second mold placed so that they sandwich an optical material and face each other; and a first spacer and a second spacer provided between the first and second molds, wherein: the first spacer secures an interval between the first and second molds at a first temperature achieved in a process of pressurizing the optical material; the first spacer shrinks in a mold opening-closing direction more greatly than the second spacer while the first temperature is changing to a second temperature achieved in a process of cooling the optical material; and the second spacer secures the interval between the first and second molds at the second temperature.

Abstract: A mold set includes: a first mold and a second mold placed so that they sandwich an optical material and face each other; and a first spacer and a second spacer provided between the first and second molds, wherein: the first spacer secures an interval between the first and second molds at a first temperature achieved in a process of pressurizing the optical material; the first spacer shrinks in a mold opening-closing direction more greatly than the second spacer while the first temperature is changing to a second temperature achieved in a process of cooling the optical material; and the second spacer secures the interval between the first and second molds at the second temperature.