| 摘要 |
<p>An imaging lens system according to the present invention is an infrared imaging lens having a 120° or more diagonal angle of view when forming an image of a subject on an imaging element, wherein the imaging lens system comprises a first lens (2) having a negative power and a concave surface toward an image, an aperture diaphragm (3), a second lens (4) having a positive power and a convex surface toward the image, and a third lens (5) having a positive power and a convex surface toward the image in that order from the object, and satisfies a formula: 45°≤α≤70°⋅⋅⋅(1) whereαis the maximum value in the angles of a line tangent to the lens surface of the first lens (2) on the image side. The present invention makes it possible to provide a compact and low-cost imaging lens system capable of photographing the image of a subject with a diagonal angle of view of 120° or more, and having excellent telecentricity and favorable resolution.</p> |
