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Objective lens, optical pickup device and information recording regeneration method

An optical pickup and information recording technology, applied in the field of objective lens system, can solve the problems of deteriorating focus noise, increasing noise signal during focusing process, increasing spot light, etc.

Inactive Publication Date: 2007-01-24
KONICA CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The closer the inner diameter of the spot is to the converging spot, the more the spot light that is not expected to be detected by the photodetector increases, and the noise signal in the focusing process is increased, which is not ideal.
In other words, if you want to improve the temperature characteristics and strengthen the diffraction effect, there will be problems such as worsening focus noise.

Method used

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  • Objective lens, optical pickup device and information recording regeneration method
  • Objective lens, optical pickup device and information recording regeneration method
  • Objective lens, optical pickup device and information recording regeneration method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0159] This embodiment is related to the above-mentioned first embodiment, and it is about using DVD as the first optical information recording medium with high recording density and using CD as the second optical information recording medium with low recording density, and it is possible to store information on them respectively. Examples of recording or reproducing objective lenses.

[0160] In DVD, the thickness of the transparent substrate of the optical information recording medium is 0.6mm, the necessary numerical aperture NA1=0.60, and the wavelength of the light source λ 1 =655nm, in CD, the thickness of the transparent substrate of the optical information recording medium is 1.2mm, the necessary numerical aperture NA2=0.45, the light source wavelength λ 2 =785nm.

[0161] Both surfaces of the objective lens are aspheric surfaces represented by [Formula 1]. Here, Z is the axis in the direction of the optical axis, h is the axis perpendicular to the optical axis, r is...

Embodiment 2

[0214] This embodiment is related to the above-mentioned second embodiment, and it is about using a DVD as a first optical information recording medium with a high recording density and using a CD as a second optical information recording medium with a low recording density, and it is possible to store information on them separately. Examples of recording or reproducing objective lenses. Here, descriptions that overlap with Embodiment 1 are omitted.

[0215] In this embodiment, the feature is that by setting the manufacturing wavelength (the wavelength used for the shape design of the diffractive structure) to a shorter wavelength than the DVD wavelength in the diffractive structure of the outer optical function region, it is possible to ease the passage of time when using a CD. Noise caused by beams in the outer area.

[0216] [Table 3] provides the lens data of the objective lens of the present embodiment, and the spherical aberration diagram is shown in Figure 9 . Figu...

Embodiment 3

[0261] This embodiment is related to the above-mentioned third embodiment, and it is about using DVD as the first optical information recording medium with high recording density and using CD as the second optical information recording medium with low recording density, and it is possible to store information on them respectively. Examples of recording or reproducing objective lenses.

[0262] In DVD, the thickness of the transparent substrate of the optical information recording medium is 0.6mm, the necessary numerical aperture NA1=0.60, and the wavelength of the light source λ 1 =655nm, in CD, the thickness of the transparent substrate of the optical information recording medium is 1.2mm, the necessary numerical aperture NA2=0.45, the light source wavelength λ 2 =785nm.

[0263] The objective lens has two aspherical surfaces, and the surface on the light source side is composed of three optical functional areas, which are used for different purposes. Such as figure 2 As ...

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Abstract

The invention provides an objective lens for an optical pickup device and an optical pickup device each having a simple structure with which the recording or the reproducing of information is properly performing on different optical information recording media, and a method for recording and reproducing information. The transmissivity of a luminous flux having a wavelength λ 2 for a CD(compact disk) is lower than the transmissivity of a wavelength λ 1 for a DVD(digital versatile disc) thus reflection light from the CD is hardly detected with an optical detector 106 which detects the reflected light from the CD, thus the possibility of an erroneous detection is suppressed even when the overflare part of the luminous flux used for recording or reproducing information on the CD is directed to the under direction due to the enhancement of the wavelength-dependency of a diffraction structure and accordingly the flare part approaches to an optical axis.

Description

technical field [0001] The present invention relates to an objective lens system used in an optical pickup device, an optical pickup device, and an information recording and reproducing device, and in particular to an objective lens, an optical pickup device, and an information recording system for recording / reproducing optical information recording media with different recording densities with one objective lens Reproducing device, furthermore, also relate to form diffraction structure on objective lens and can use with limited magnification (relative to the magnification of limited light), and satisfy good temperature characteristic in the optical information recording medium of high recording density, can reduce again simultaneously Noise signal objective lens, optical pick-up device and information recording and reproducing device when focusing and driving an optical information recording medium with low recording density. Background technique [0002] There are currentl...

Claims

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Application Information

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IPC IPC(8): G02B13/18G02B27/42G11B7/135G11B7/00G11B7/125
CPCG11B7/1374G11B7/1275G11B2007/0006G11B7/13922G11B7/1353
Inventor 坂本勝也
Owner KONICA CORP
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