Abstract: An optical device includes a first optical component and a second optical component that are adjacent to each other in a direction of an optical axis. The optical device further includes a holding member that is formed with a resin material absorbing laser beams and that holds the first optical component via an elastic property of the resin material. The second optical component is formed with a resin material that allows the laser beams to pass and that is compatible with the resin material forming the holding member, and is fixed to the holding member by laser welding.

Abstract: An optical device includes a first optical component and a second optical component that are adjacent to each other in a direction of an optical axis. The optical device further includes a holding member that is formed with a resin material absorbing laser beams and that holds the first optical component via an elastic property of the resin material. The second optical component is formed with a resin material that allows the laser beams to pass and that is compatible with the resin material forming the holding member, and is fixed to the holding member by laser welding.

Abstract: An impeller for a circumferential current pump is provided with a plurality of vanes, and each of the vanes has an upstream side surface and a downstream side surface in a rotating direction thereof and a center line between both these surfaces extends along a radial direction of a disc-shape member, the upstream side surface has a radially inside portion and a radially outside portion which are formed to be continuous so that the radially inside portion is in parallel to the center line and the radially outside portion is inclined forward in the rotating direction of the disc-shape member, and the downstream side surface is formed entirely to be parallel to the center line.

Abstract: An impeller for a circumferential current pump is injection molded and can be used as it is without being polished. The impeller (7) is provided with a plurality of vane grooves (12) on an outer periphery of a synthetic resin disc-like member (8) rotated by a motor, and is rotatably received with a substantially disc-like space (6) formed between a pump casing (4) and a pump cover (5). A disc-like recess portion (14) is formed in both side surfaces (10, 11) of the disc-like member (8). A formation is performed so that a ratio (L/2t) between the sum (t1+t2=2t) of a gap (t1) between one side surface (10) and the pump casing (4) and a gap (t2) between another side surface (11) and the pump cover (5), and a size (L=R0−H−R1) obtained by subtracting a radical groove length (H) of the vane groove (12) and a radial size (R1) of the recess portion (14) from a radial size (R0) of the disc-like member (8) satisfies a relation 66≦(L/2t).

Abstract: An impeller for a circumferential current pump is provided with a plurality of vanes, and each of the vanes has an upstream side surface and a downstream side surface in a rotating direction thereof and a center line between both these surfaces extends along a radial direction of a disc-shape member, the upstream side surface has a radially inside portion and a radially outside portion which are formed to be continuous so that the radially inside portion is in parallel to the center line and the radially outside portion is inclined forward in the rotating direction of the disc-shape member, and the downstream side surface is formed entirely to be parallel to the center line.