Abstract: A variable magnification optical system comprising, in order from an object side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a rear lens group having negative refractive power; upon varying a magnification from a wide angle end state to a tele photo end state, a distance between the first lens group and the second lens group being varied, a distance between the second lens group and the third lens group being varied, and a distance between the third lens group and the rear lens group being varied; the third lens group or the rear lens group comprising a focusing lens group which is moved upon carrying out focusing from an infinitely distant object to a closely distant object; and predetermined conditional expression(s) being satisfied, thereby various aberrations being corrected superbly.

Abstract: A variable magnification optical system comprising, in order from an object side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a rear lens group having positive refractive power; upon varying a magnification, a distance between the first lens group and the second lens group being varied, a distance between the second lens group and the third lens group being varied, and a distance between the third lens group and the rear lens group being varied; the rear lens group comprising a focusing lens group which is moved upon carrying out focusing from an infinitely distant object to a closely distant object; and predetermined conditional expression(s) being satisfied, thereby various aberrations being corrected superbly.

Abstract: A zoom lens includes a first lens group having negative refractive power; a second lens group having positive refractive power; a third lens group having negative refractive power and a fourth lens group having positive refractive power. Upon varying magnification, distances between the first lens group and the second lens group, between the second lens group and the third lens group and between the third lens group and the fourth lens group vary. The second lens group includes a front lens group, an aperture stop, and a rear lens group. Each of the front lens group and the rear lens group includes at least one positive lens. At least a part of the lenses in the second lens group is moved as a group to have a component in a direction perpendicular to an optical axis.

Abstract: A vehicle electricity storage device includes a capacitor unit for supplying stored electric power to an electronically controlled system, and a microcomputer including a memory. The memory stores a plurality of thresholds (internal resistance limit values) different from each other. Each of the plurality of thresholds is to be compared with an electrical characteristic value (internal resistance value) related to the capacitor unit for determining a deterioration state of the capacitor unit. The each of the plurality of thresholds is stored in association with an identification ID for identifying the electronically controlled system. The microcomputer acquires the identification ID from the electronically controlled system. And the microcomputer selects, from the plurality of thresholds, a threshold associated with the identification ID acquired. Then the microcomputer determines the deterioration state of the capacitor unit by using the electrical characteristic value and the threshold selected.

Abstract: A zoom optical system (ZL) comprises: a first lens group (G1) disposed closest to an object and having a positive refractive power; an aperture stop (S) disposed closer to an image than the first lens group (G1); a positive lens component disposed so as to oppose the image side of the aperture stop (S); and a lens group (G3) having the positive lens component, wherein a distance between the first lens group (G1) and the lens group (G3) having the positive lens component changes during zooming, at least one lens surface of the positive lens component has an aspherical surface, and the following conditional expression, 0.40<fp/fGp<3.60 is satisfied, where fp: a focal length of the positive lens component, and fGp: a focal length of the lens group (G3) having the positive lens component.

Abstract: A zoom lens includes, in order from an object along an optical axis: a first lens group having a negative refractive power; a second lens group having a positive refractive power; a third lens group having a negative refractive power; a fourth lens group; and a fifth lens group. When the zoom lens performs varying magnification, the distance between the first and second lens groups changes, the distance between the second and third lens groups changes, the distance between the third and fourth lens groups changes, the distance between the fourth and fifth lens groups changes, the second and fourth lens groups move along the same trajectory along the optical axis, and at least the third lens group moves along the optical axis.

Abstract: A zoom optical system (ZL) comprises a first negative lens group (G2) having a negative refractive power; and a second negative lens group (G4) disposed closer to an image than the first negative lens group (G2), wherein a distance between the first negative lens group (G2) and the second negative lens group (G4) changes during zooming, at least part of the first negative lens group (G2) is movable so as to have a displacement component in a direction perpendicular to an optical axis, at least part of the second negative lens group (G4) is movable along the optical axis during focusing, and the following conditional expression, 0.50<fGb/fGa<2.60 is satisfied, where, fGa: a focal length of the first negative lens group (G2), and fGb: a focal length of the second negative lens group (G4).

Abstract: A zoom lens includes, in order from an object along an optical axis: a first lens group having a negative refractive power; a second lens group having a positive refractive power; a third lens group having a negative refractive power; a fourth lens group; and a fifth lens group. When the zoom lens performs varying magnification, the distance between the first and second lens groups changes, the distance between the second and third lens groups changes, the distance between the third and fourth lens groups changes, the distance between the fourth and fifth lens groups changes, the second and fourth lens groups move along the same trajectory along the optical axis, and at least the third lens group moves along the optical axis.

Abstract: A manufacturing method includes, cutting out a plurality of rings, polishing the rings, adjusting the plurality of rings so that they exhibit circumferential lengths respectively predetermined for them, nitriding the plurality of rings, and assembling in order to layer the plurality of rings into a multi-layered ring; wherein after the rings are cut out from the pipe, each of them is polished one by one so that their order is not changed; in nitriding, they are subjected to a nitriding process in a state where they are set in a jig in order to keep their order; and in assembling, the rings are assembled so that rings that were parts originally adjacent to each other in a state of the pipe become layers that are adjacent to each other in the multi-layered ring.

Abstract: A zoom lens includes, in order from an object along an optical axis: a first lens group having a negative refractive power; a second lens group having a positive refractive power; a third lens group having a negative refractive power; a fourth lens group; and a fifth lens group. When the zoom lens performs varying magnification, the distance between the first and second lens groups changes, the distance between the second and third lens groups changes, the distance between the third and fourth lens groups changes, the distance between the fourth and fifth lens groups changes, the second and fourth lens groups move along the same trajectory along the optical axis, and at least the third lens group moves along the optical axis.

Abstract: A zoom lens comprises, in order from an object side: a first lens group G1 having negative refractive power; a second lens group G2 having positive refractive power; a third lens group G3 having negative refractive power and a fourth lens group G4 having positive refractive power. Upon varying magnification, a distance between the first lens group G1 and the second lens group G2, a distance between the second lens group G2 and the third lens group G3 and a distance between the third lens group G3 and the fourth lens group G4 are varied. The second lens group G2 includes, in order from the object side, a front lens group G2F, an aperture stop S, and a rear lens group G2R. Each of the front lens group G2F and the rear lens group G2R includes at least one negative lens. At least a part of the lenses in the second lens group G2 is moved as a movable group to have a component in a direction perpendicular to the optical axis. Thus, the zoom lens can have high optical performances.

Abstract: A zoom lens comprises a first lens group having negative refractive power; a second lens group having positive refractive power; a third lens group having negative refractive power and a fourth lens group having positive refractive power. Upon varying magnification, distances between the first lens group and the second lens group, between the second lens group and the third lens group and between the third lens group and the fourth lens group vary. The second lens group includes a front lens group, an aperture stop, and a rear lens group. Each of the front lens group and the rear lens group includes at least one negative lens. At least a part of the lenses in the second lens group is moved as a group to have a component in a direction perpendicular to an optical axis.

Abstract: A zoom lens comprises, in order from an object side: a first lens group G1 having negative refractive power; a second lens group G2 having positive refractive power; a third lens group G3 having negative refractive power and a fourth lens group G4 having positive refractive power. Upon varying magnification, a distance between the first lens group G1 and the second lens group G2, a distance between the second lens group G2 and the third lens group G3 and a distance between the third lens group G3 and the fourth lens group G4 are varied. The second lens group G2 includes, in order from the object side, a front lens group G2F, an aperture stop S, and a rear lens group G2R. Each of the front lens group G2F and the rear lens group G2R includes at least one negative lens. At least a part of the lenses in the second lens group G2 is moved as a movable group to have a component in a direction perpendicular to the optical axis. Thus, the zoom lens can have high optical performances.

Abstract: A manufacturing method includes, cutting out a plurality of rings, polishing the rings, adjusting the plurality of rings so that they exhibit circumferential lengths respectively predetermined for them, nitriding the plurality of rings, and assembling in order to layer the plurality of rings into a multi-layered ring; wherein after the rings are cut out from the pipe, each of them is polished one by one so that their order is not changed; in nitriding, they are subjected to a nitriding process in a state where they are set in a jig in order to keep their order; and in assembling, the rings are assembled so that rings that were parts originally adjacent to each other in a state of the pipe become layers that are adjacent to each other in the multi-layered ring.

Abstract: A hearing aid (100) comprises a body case (2) that is worn behind an ear (1), a sound conductor (3) that is linked at one end to the body case (2) and is linked at the other end to an earpiece (6), and an engaging component (8) for holding the earpiece linked to the other end of the sound conductor in the external auditory canal (7) of the ear (1). The engaging component (8) is made up of a first arc part (8a) disposed on the earpiece (6) side, a second arc part (8b) that is larger than the first arc part (8a) and is disposed opposite the first arc part (8a), a first linking part (8c) that links one end of the first arc part (8a) and one end of the second arc part (8b), and a second linking part (8d) that links the other end of the first arc part (8a) and the other end of the second arc part (8b). The second linking part (8d) has a shape such that its center part protrudes toward the first linking part (8c). This constitution allows the hearing aid (100) to be put on more easily.

Abstract: A hearing aid (100) comprises a body case (2) that is worn behind an ear (1), a sound conductor (3) that is linked at one end to the body case (2) and is linked at the other end to an earpiece (6), and an engaging component (8) for holding the earpiece linked to the other end of the sound conductor in the external auditory canal (7) of the ear (1). The engaging component (8) is made up of a first arc part (8a) disposed on the earpiece (6) side, a second arc part (8b) that is larger than the first arc part (8a) and is disposed opposite the first arc part (8a), a first linking part (8c) that links one end of the first arc part (8a) and one end of the second arc part (8b), and a second linking part (8d) that links the other end of the first arc part (8a) and the other end of the second arc part (8b). The second linking part (8d) has a shape such that its center part protrudes toward the first linking part (8c). This constitution allows the hearing aid (100) to be put on more easily.

Abstract: The forming recesses of a lower die and an upper die are formed to have a semi-oval profile so as to provide a forming space almost oval in section with the dies closed. The parting line between the lower die and the upper die is deviated as much as h from the major axis of the forming space toward the upper die side, and the opening width of the forming recess of the lower die is set to be slightly larger than the opening width of the forming recess of the upper die. A metal bent tube is plastic-deformed into an almost oval shape in section by closing the dies while being compressed in a peripheral direction by the lower and upper dies to eliminate spring-back caused by bending, whereby the buckling and pinching toward the outer side of the tube wall is prevented by the expanded portion of the lower die and buckling toward the inner side of the tube wall is prevented by a step difference formed by the difference in opening width between the lower die and the upper die.

Abstract: The forming recesses of a lower die and an upper die are formed to have a semi-oval profile so as to provide a forming space almost oval in section with the dies closed. The parting line between the lower die and the upper die is deviated as much as h from the major axis of the forming space toward the upper die side, and the opening width of the forming recess of the lower die is set to be slightly larger than the opening width of the forming recess of the upper die. A metal bent tube is plastic-deformed into an almost oval shape in section by closing the dies while being compressed in a peripheral direction by the lower and upper dies to eliminate spring-back caused by bending, whereby the buckling and pinching toward the outer side of the tube wall is prevented by the expanded portion of the lower die and buckling toward the inner side of the tube wall is prevented by a step difference formed by the difference in opening width between the lower die and the upper die.