Patent ID: 8848501

Claim:
A detection lens, comprising: a lens portion; and a flange portion including a first surface, to which the lens portion is connected, and a second surface opposite to the first surface, wherein the flange portion includes a base disposed along an optical axis of the lens portion, a first projection, which projects along a first axis orthogonal to the optical axis, a second projection, which is point-symmetric to the first projection around the optical axis and projects from the base, a third projection, which projects along a second axis orthogonal to the optical axis and the first axis, and a fourth projection, which is point-symmetric to the third projection around the optical axis and projects from the base, the flange portion does not have a projection which extends beyond the second surface, the first projection includes a first intersecting surface which intersects with the first axis, the second projection includes a second intersecting surface which intersects with the first axis, the third projection includes a third intersecting surface which intersects with the second axis, the fourth projection includes a fourth intersecting surface which intersects with the second axis, and a first distance between the first and second intersecting surfaces is longer than a second distance between the third and fourth intersecting surfaces.