Optical head device

Abstract

Abstract An optical head device for recording and/or reproducing information by using an optical recording medium (C) includes a light source (1), an objective lens (4), a photo detector (10), an optical system including a collimator lens (2), a beam splitter (3), a convergent lens (8) and a cylindrical lens (9), a housing (17) for accommodating the light source (1), the photo detector (10) and the optical system (2, 3, 4, 8, 9), and an optical glass plate (15) for reducing aberration of the optical system and the objective lens (4). A light beam from the light source (1) is turned to a parallel beam flux by the collimator lens (2) to irradiate the objective lens (4), which provided drivably converges the parallel beam flux on the optical recording medium (C). The light beam reflected from the optical recording medium passes through the objective lens (4) and reflected by the beam splitter (3) in the optical system toward the photo detector (10). The light beam reflected by the beam splitter (3) is converged on the photo detector (10) by the convergent lens (8) and the cylindrical lens (9). The characteristic of the present invention is that the optical glass plate (15) for reducing the aberration seals the housing (17) to protect the light source (1) and the optical system (2, 3, 4, 8, 9) from dust. The optical glass plate (15) is set rotated about the axis (16) of the parallel beam flux to a position reducing the aberration of the optical system and of the objective lens.

Inventors

• 👤 Hiroshi Katayama

Bibliographic Details