Patent attributes
A lens unit including a first lens including a first lens section having a first optical axis along which light passes, and a second lens. The second lens includes a second lens section having a second optical axis along which light passes, and a flange provided at the outer circumferential part of the second lens section and having a surface opposed to the first lens, and a tubular section extending from the flange in the direction of the second optical axis and having an inner side face opposed to the second lens section. The first lens is fitted in the tubular section and in contact with the inner side face of the tubular section of the second lens. The tubular section of the second lens has a plurality of protrusions protruding in the direction of the second optical axis and a plurality of valleys provided between the protrusions.