An imaging lens system includes a first lens group, a first reflective portion including a plurality of reflective surfaces, and a second reflective portion including a plurality of reflective surfaces. The first lens group, the first reflective portion, and the second reflective portion are sequentially arranged from an object side, and 2.0 < TTL/f1 < 4.0 is satisfied, where TTL is a distance from an object-side surface of a first lens of the first lens group to an imaging plane, and f1 is a focal length of the first lens.

An imaging lens system includes a first lens group, a first reflective portion including a plurality of reflective surfaces, and a second reflective portion including a plurality of reflective surfaces. The first lens group, the first reflective portion, and the second reflective portion are sequentially arranged from an object side, and 2.0 < TTL/f1 < 4.0 is satisfied, where TTL is a distance from an object-side surface of a first lens of the first lens group to an imaging plane, and f1 is a focal length of the first lens.

In a propagation optical system to propagate light from an image display element to a light guide element, the propagation optical system includes: a prism having a first surface having negative power to which light emitted from the image display element enters; and a lens group having positive power. The prism and the lens group are arranged between the image display element and the light guide element along an optical axis, and the prism is closer to the image display element than to the light guide element.

In a propagation optical system to propagate light from an image display element to a light guide element, the propagation optical system includes: a prism having a first surface having negative power to which light emitted from the image display element enters; and a lens group having positive power. The prism and the lens group are arranged between the image display element and the light guide element along an optical axis, and the prism is closer to the image display element than to the light guide element.

There is provided converter lens system including a first lens that is a negative lens of which both surfaces are concave, a second lens that is a negative lens of which both an image plane side and an object side are convex toward an object side, and a third lens that is a positive lens of which both sides are convex. The first to third lenses are disposed in this order from the object side, and the converter lens system is inserted and used between an imaging lens and a camera.

There is provided converter lens system including a first lens that is a negative lens of which both surfaces are concave, a second lens that is a negative lens of which both an image plane side and an object side are convex toward an object side, and a third lens that is a positive lens of which both sides are convex. The first to third lenses are disposed in this order from the object side, and the converter lens system is inserted and used between an imaging lens and a camera.

A lens barrel includes an optical element with a peripheral portion having a side face and a planar bottom face. The lens barrel includes a first member configured to position the side face in a direction orthogonal to an optical axis, and a second member configured to position the bottom face in a direction of the optical axis. The first member and the second member are fixed in a state in which the first member and the second member are positioned relative to each other in the direction of the optical axis with an abutting face of the first member and an abutting face of the second member being abutted on each other.

The present disclosure discloses an optical imaging lens assembly, and the optical imaging lens assembly includes, sequentially from an object side to an image side along an optical axis: a first lens having positive refractive power, and at least one subsequent lens having refractive power. An F-number Fno1 of the optical imaging lens assembly satisfies Fno1>3.5, where an object distance is finite, and an F-number Fno2 of the optical imaging lens assembly satisfies Fno2≥1.0, where the object distance is infinite.

The present disclosure discloses an optical imaging lens assembly, and the optical imaging lens assembly includes, sequentially from an object side to an image side along an optical axis: a first lens having positive refractive power, and at least one subsequent lens having refractive power. An F-number Fno1 of the optical imaging lens assembly satisfies Fno1>3.5, where an object distance is finite, and an F-number Fno2 of the optical imaging lens assembly satisfies Fno2≥1.0, where the object distance is infinite.

A method of manufacturing an optical structure may include providing a base structure that includes a substrate having an optical element extending from a first side of the substrate and dispensing liquid photoresist onto the base structure. The method may further include forming a layer of said liquid photoresist where the height of said layer is controlled by lowering the tool to a height above said substrate, and forming a spacer from the liquid photoresist by exposing a portion of the liquid photoresist to ultraviolet light. The spacer may include a central aperture above the optical element.