Patent ID: 6839315
Filing Date: 2005-01-04
Classification: G11B

Abstract:
1. An optical head having: a bobbin formed with a center hole and a first optical lens mounted on said bobbin via a thermal expansion adjustment member formed with an opening, said first optical lens having a substrate formed by an optical, material different from said bobbin in coefficient of thermal expansion, said substrate having: a convex part functioning as a convex lens and a flat part positioned around said convex part, said flat part is fixed to said thermal expansion adjustment member so that said convex part fits in said opening, and said first optical lens is placed so that a center axis of said convex part or an extension thereof passes through the center hole of said bobbin, wherein the coefficient of thermal expansion of said thermal expansion adjustment member is a value between the coefficient of thermal expansion of said bobbin and the coefficient of thermal expansion of said first optical lens.