Patent ID: 8976464
Filing Date: 2015-03-10
Classification: G02B,H04N

Abstract:
1. A fixed-focus imaging lens which forms an image of an object on a solid-state image sensor, in which elements are arranged in order from an object side to an image side, comprising: an aperture stop; a first lens with positive refractive power having convex surfaces on the object side and the image side; a second lens as a double-sided aspheric lens with negative refractive power having a concave surface on the object side near an optical axis; a third lens as a meniscus double-sided aspheric lens with positive refractive power having a convex surface on the image side near the optical axis; and a fourth lens as a meniscus double-sided aspheric lens with negative refractive power having a concave surface on the image side near the optical axis, wherein all the lenses are made of plastic material; and wherein conditional expressions (1), (2), (3), and (4) below are satisfied; where f: focal length of the overall optical system of the imaging lens f1: focal length of the first lens f3: focal length of the third lens r1: curvature radius of the object-side surface of the first lens r3: curvature radius of the object-side surface of the second lens r4: curvature radius of the image-side surface of the second lens r7: curvature radius of the object-side surface of the fourth lens r8: curvature radius of the image-side surface of the fourth lens.