Patent ID: 11867966
Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 0:
1. A lens system for forming an image of light incident from an object side on an imaging element arranged on an image surface side, the lens system comprising: a plurality of lens elements including free-curved surface lenses; and a diaphragm arranged between the plurality of lens elements, wherein the plurality of lens elements form a front group arranged on the object side of the diaphragm, and a rear group arranged on the image surface side of the diaphragm, wherein a first lens element has an aspherical surface that is rotationally symmetrical, the first lens element being closest to the object side in the plurality of lens elements, wherein the free-curved surface lenses each has a free-curved surface that is asymmetrical with respect to a first direction and a second direction, and are arranged in the front group and the rear group respectively, the first and second directions crossing with each other, wherein a free-curved surface lens satisfying following conditional expression (i) is arranged on the rear group in the plurality of lens elements,

D×(SV−SH)/IH>0.08  (1)

where, IH: a height at which a ray with an angle of view of 300 forms an image on the image surface, in the first direction; SH: a sag amount at the height IH of the free-curved surface, in the first direction; SV: a sag amount at the height IH of the free-curved surface, in the second direction; and D: “1” in a case where the free-curved surface is on the object side of the free-curved surface lens, or “−1” in a case where the free-curved surface is on the image surface side of the free-curved surface lens.