Patent ID: 8792187
Filing Date: 2014-07-29
Classification: G02B

Abstract:
1. An imaging lens having an object side and an imaging side, the imaging lens comprising: a first plastic lens element that is biconvex, has a positive focusing power, and an object-side surface facing the object side; a second plastic lens element that is biconcave and has a negative focusing power and an abbe number not greater than 30, said second plastic lens element being adjacent to said first plastic lens element; a third plastic lens element that has a positive focusing power and a convex imaging-side surface facing toward the imaging side, said third plastic lens element being adjacent to said second plastic lens element; a fourth plastic lens element that has an imaging-side surface facing toward the imaging side with a concave area in a vicinity of an optical axis of said fourth plastic lens element, said fourth plastic lens element being adjacent to said third plastic lens element; an aperture stop disposed between said first and said second plastic lens elements; and an imaging plane disposed at the imaging side, wherein said imaging lens further satisfies the optical conditions of: wherein said imaging lens does not include any lens element with focusing power other than said first, second, third, and fourth plastic lens elements.