Optical disk device

Abstract

The present invention provides an optical disc device which can perform information recording and regenerating properly even to the optical disc that covers the first recording layer and the second recording layer with euphotic layers having different thickness. The optical disc device (1) performes information recording and / or regenerating to DVD and CD (11,12), at the same time, the optical disk (11) can perform information recording and regenerating even to optical disc of one-side-two-layer DVD-ROM form which covers the fist recording layer and the second recording layer with the first euphotic layer and the second euphotic layer which hase a different thickness from the first euphotic layer. Lambadda1 and SA5 are provided as the following formula: -0.025lambadda1rms<=SA5<=+0.025lambadda1rms, when the spherical aberration of five power of the field lens (45) for performing information recording and regenerating to optical disk (11) by a laser (L1) having a wavelength of lambadda1 are set to be SA5.

Description

technical field [0001] The present invention relates to an optical disc device for recording and / or reproducing information on an optical disc (optical recording disc) in which a first recording layer and a second recording layer are covered with light-transmitting layers having different thicknesses. Background technique [0002] In an optical disk device, laser light emitted from a laser light source passes through a light-transmitting layer (light-transmitting substrate) in an optical disk through an objective lens, and is focused on a recording layer to record and reproduce information on the optical disk. As such an optical disc device, a device capable of recording and reproducing information on optical discs having different thicknesses of the light-transmitting layer has been proposed. A device for recording and reproducing information on two kinds of optical discs of the second optical disc of the compact disc) standard. Here, the thickness of the light-transmittin...

AI Technical Summary

Problems solved by technology

First, when adopting the first structure, there are two types of spherical aberration, the third-order spherical aberration and the higher-order spherical aberration, so it is difficult to exert the performance of a single-sided double-layer DVD-ROM standard disc.

In addition, when adopting the second structure, although the third-order spherical aberration can be eliminated, there is a problem that the light-gathering margin of a single-sided double-layer DVD-ROM standard disc is small due to the presence of higher-order spherical aberration.

Furthermore, when adopting the third structure, although the spherical aberration can be eliminated in the design center, since the principle of diffraction is used, the wavelength of the laser light is likely to vary with each ambient temperature and laser light source, so there is a possibility of aberration caused by this. question

Images