Optical lens

Abstract

An optical lens comprising a first lens (L), a second lens (L), and a third lens (L) that are sequentially arranged on a common optical axis in the transmission direction of an incident light. Both the first lens and the second lens are positive plano-convex lenses. The third lens is a negative meniscus lens. The first lens comprises a first curved surface (S) and a second curved surface (S). The second lens comprises a third curved surface (S) and a fourth curved surface (S). The third lens comprises a fifth curved surface (S) and a sixth curved surface (S). The two curved surfaces of each lens respectively are the light incident surface and the light exit surface of the lens. The first to the sixth curved surfaces are sequentially arranged in the transmission direction of the incident light. The first curved surface and the third curved surface protrude in reverse to the transmission direction of the incident light. The fifth curved surface and the sixth curved surface protrude in the transmission direction of the incident light. The third curved surface is constituted by connecting sequentially and directly multiple arced surfaces (Φ, and Φ) having different focuses and all of the focuses (f, f, f, f, and f) of these arced surfaces are located on the optical axis. The optical lens is applicable in processing deep and fine holes or engraving deep and fine lines.