Abstract: An epoxy resin, comprising an epoxy compound having two or more mesogenic structures, and having a loss tangent of 1 or more at 35° C. before curing.

Abstract: A casing unit includes a first casing, and a second casing configured to be combined with the first casing from a first direction. The first casing includes a first casing main body and a protrusion. The second casing includes a second casing main body provided with an accommodating groove into which the protrusion is to be accommodated. Any one of the protrusion and the second casing main body is provided with a guiding part that relatively moves the first casing and the second casing in a second direction, in response to combining the first casing and the second casing. The second casing further includes an overlapping part that overlaps with the first casing main body in the first direction in a combined state, and that is elastically deformable in response to relative movement of the first casing and the second casing in the second direction.

Abstract: A lens barrel includes: a first lens holding frame; a fixed barrel holding the first lens holding frame and including an elongated window provided radially; and a first step-type eccentric roller rotatably fixed to the first lens holding frame. The first step-type eccentric roller includes usable and non-usable regions on a periphery substantially perpendicular to the rotation axis, a distance from a center of the rotation axis to any point within any one of the usable regions is constant, and the distance is different for each of the usable regions, and the first step-type eccentric roller is fixed to the first lens holding frame by rotating the first step-type eccentric roller about the rotation axis, changing an engagement position between one of the usable regions and a side forming the polygonal shape of the elongated window, and moving the lens group parallel to an optical axis to perform shift adjustment.

Abstract: A lens barrel includes: a first ring; a second ring that switches between a first position and a second position by sliding in an optical axis direction; a plurality of biasing mechanisms that are provided on one of the first ring and the second ring, and providing adjustable biasing force in a radial direction; and a locking portion provided on the other of the first ring and the second ring on which the plurality of biasing mechanisms are not provided. The plurality of biasing mechanisms each include an elastic component having a contact portion and a biasing component that biases the elastic component. The first ring and the second ring are integrally rotatable when the contact portion contacts the locking portion which opposes the contact portion when the second ring is at the second position.

Abstract: A lens barrel includes: a first ring; a second ring that switches between a first position and a second position by sliding in an optical axis direction; a plurality of biasing mechanisms that are provided on one of the first ring and the second ring, and providing adjustable biasing force in a radial direction; and a locking portion provided on the other of the first ring and the second ring on which the plurality of biasing mechanisms are not provided. The plurality of biasing mechanisms each include an elastic component having a contact portion and a biasing component that biases the elastic component. The first ring and the second ring are integrally rotatable when the contact portion contacts the locking portion which opposes the contact portion when the second ring is at the second position.