Patent ID: 9025073
Filing Date: 2015-05-05
Classification: G03B,H04N

Abstract:
1. An optical assembly comprising four even aspheric lenses arranged along an optical axis and configured to form an image of an object onto a focal plane, such that a total track length from a front surface of the optical assembly to the focal plane is no greater than about 5 millimeters (mm), the lenses having alternating positive and negative respective refractive powers; wherein: the four even aspheric lenses include a first lens adjacent to a second lens, both the first lens and the second lens being meniscus lenses, the four even aspheric lenses include a third lens and a fourth lens, wherein the first lens, second lens, third lens and fourth lens are arranged in numerical order of decreasing distance from the focal plane along the optical axis, such that the first lens is furthest from the focal plane and the fourth lens nearest to the focal plane, and the fourth lens has a first surface and a second surface each comprising respective convex and concave areas.