Condenser lens for optical disks

Abstract

Abstract A condenser lens (13) to be used for an optical head capable of recording or reading information on or from optical disks (6, 7) having different substrate thicknesses in an optical disk device such as a CD or the like. A light beam emitted from a laser light source (11) is focused by a condenser lens (13) to form a minute spot. The incident surface of the condenser lens (13) is divided into a plurality of division areas which are sufficiently small with respect to the lens opening. The division areas constitute first and second lens surfaces (14, 15) , that is, parts of lens surfaces of two different lenses. The light beam is focused by the first lens surface (14) to form a minute spot on a first optical disk (6) and by the second lens surface (15) to from a minute spot on a second optical disk (7). The two lenses can be optimized independently and be designed readily. One condenser lens (13) having the first and second lens surfaces (14, 15) can form two kinds of light beam spots and adaptable to two optical disks (6, 7) having different substrate thicknesses.

Inventors

• 👤 Yutaka Yamanaka

Bibliographic Details