Lens assembly

摘要

A lens assembly includes a lens set which includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence along an optical axis. The first lens has a positive optical power. The second lens has a positive optical power. The third lens has a negative optical power. The fourth lens has a positive optical power, and has an image-side surface, an object-side surface, and a peripheral surface interconnecting the two. At least one of the object-side and image-side surfaces has an inflection point located between the optical axis and the peripheral surface. The lens assembly satisfies 15

主权项

1. A lens assembly comprising:
a lens set which includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence from an object side to an image side along an optical axis of said lens assembly, wherein
said first lens has a positive optical power adjacent to the optical axis, and has a convex object-side surface which faces the object side, and an image-side surface which faces the image side, at least one of said object-side surface and said image-side surface of said first lens being an aspherical surface,said second lens has a positive optical power adjacent to the optical axis, and has a convex image-side surface which faces the image side, and a concave object-side surface which faces the object side, at least one of said object-side surface and said image-side surface of said second lens being an aspherical surface,said third lens has a negative optical power adjacent to the optical axis, and has a concave object-side surface which faces the object side, and a convex image-side surface which faces the image side, at least one of said object-side surface and said image-side surface of said third lens being an aspherical surface,said fourth lens has a positive optical power adjacent to the optical axis, and has an image-side surface which faces the image side and which has a concave portion around the optical axis, an object-side surface which faces the object side, and a peripheral surface which interconnects said object-side surface and said image-side surface, each of said object-side surface and said image-side surface of said fourth lens being an aspherical surface, at least one of said object-side surface and said image-side surface of said fourth lens having an inflection point located between the optical axis and said peripheral surface; and a non-adjustable diaphragm located between the object side and said second lens of said lens set; wherein said lens assembly satisfies
15