Optical pickup apparatus

Abstract

An optical pickup apparatus comprising: a collimating lens configured to convert laser light having Gaussian distribution property emitted from a laser diode from divergent light to parallel light; an objective lens configured to focus the laser light from the collimating lens onto a signal recording layer of an optical disc; and an adjustment film formed on a surface of an incident face of the collimating lens on which the laser light is incident, and configured to adjust transmittance of the laser light passing through the collimating lens, the adjustment film being formed on the surface of the incident face so that the transmittance is lower on the inner side of the incident face than on the outer side of the incident face.

Description

[0001] Cross-references to related applications [0002] This application claims priority based on Japanese application No. 2007-165819 filed on June 25, 2007, and uses the contents thereof. technical field [0003] The present invention relates to an optical pickup device for reading a signal recorded on an optical disc and recording a signal on the optical disc. Background technique [0004] An optical disc device in which a signal reading operation and a signal recording operation are performed by irradiating laser light irradiated by an optical pickup device onto a signal recording layer of an optical disc is widespread. [0005] As optical disc devices, devices using optical discs such as CDs and DVDs are commonly used, and recently, optical disc devices using optical discs such as Blu-ray (Blu-ray) format, which is an optical disc with increased recording density, are being developed. [0006] Infrared light with a wavelength of 780 nm was used as laser light for read...

AI Technical Summary

Problems solved by technology

[0019] When the intensity of the laser beam incident on the entrance pupil becomes uneven in the tracking direction as the objective lens is displaced in the tracking direction, the edge intensity in the tracking direction decreases. Therefore, the laser beam condensed on the signal recording layer of the optical disc The shape of the light spot becomes larger, and as a result, there is a problem that the reproduction characteristics of the signal recorded on the optical disk and the recording characteristics of the signal on the optical disk are deteriorated.

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