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Optical read device and objective lens

A technology for optical readout and objective lens, applied in beam guiding devices, optics, optical components, etc., can solve the problems of deterioration of temperature characteristics, small chromatic aberration, residual, etc., and achieve the effect of ensuring temperature characteristics and wavelength characteristics

Inactive Publication Date: 2006-04-19
KONICA CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the laser oscillation wavelength shifts to the long wavelength side only due to the laser oscillation wavelength error, a spherical aberration occurs in the diffraction part, but the chromatic aberration of the diffraction part is smaller than the spherical aberration, and as a result, the spherical aberration of the diffraction part Components cannot be offset and remain
That is, there is a tendency that when the wavelength characteristics are improved above a certain level, the temperature characteristics begin to deteriorate, and when the temperature characteristics are improved above a certain level, the wavelength characteristics begin to deteriorate, and it is necessary to ensure a balance between the two. balance

Method used

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  • Optical read device and objective lens
  • Optical read device and objective lens
  • Optical read device and objective lens

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0123] This embodiment is an embodiment of the above-mentioned first embodiment.

[0124]Generally, the diffraction ring spacing of the diffraction surface is defined by a phase difference function or an optical path difference function. Specifically, the phase difference function Φb is represented by the following "Mathematical Formula 1" in radian units, and the optical path difference function ΦB is represented by Mathematical Formula 2 in mm.

[0125] math formula 1

[0126] Φb = Σ i = 0 ∞ b 2 i h 2 i

[0127] math formula 2

[0128] ΦB = Σ i = 0 ∞ B 2 i ...

Embodiment 2

[0177] This embodiment is an embodiment of the above-mentioned second embodiment.

[0178] Table 3 shows objective lens data. i represents the plane number, and i=1 refers to the aperture. In addition, a diffractive surface is formed on the surface of the objective lens on the laser side, i=2 means the data of the common area, and i=2' means the data of the dedicated area. i=4, 5 indicates an optical information recording medium. "A certain position h" mentioned in the claims refers to the switching position of the area, and in this embodiment, h=1.0951mm. In addition, the step difference δ at a certain position h of the parent aspheric surface of the diffractive surface is 4.1 μm, and the step difference when changed to the actual diffraction shape is 2.6 μm. Even with such a setting, the discontinuous amount of spherical aberration in the DVD can be compensated to the same extent as in the first embodiment, and there is no problem in practical use. Table 4 shows the amou...

Embodiment 3

[0216] This embodiment is the same as the second embodiment, and is an embodiment of the above-mentioned second embodiment.

[0217] Table 5 shows the objective lens data, and Table 6 shows the change amount of the spherical aberration component in the wave aberration.

[0218] DVD

cd

side i

ri

di (655nm)

ni (655nm)

di (785nm)

ni (785nm)

0

∞

1.0

∞

1.0

luminous point

1

∞

0

1.0

0

1.0

Aperture (aperture straight

Diameter4.03mm)

2’

1.9401

2.2023

1.52915

2.2023

1.52541

objective lens

2

2.081

2.2

1.52915

2.2

1.52541

3

-7.7425

1.7499

1.0

1.3873

1.0

4

∞

0.6

1.57685

1.2

1.57063

disc

5

∞

1.0

1.0

[0219] Dif...

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PUM

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Abstract

An optical pickup apparatus, comprises a first light source having a wavelength of lambda 1; a second light source having a wavelength of lambda 2 (lambda 1 is less than lambda 2); a focalizing optical system including a single objective lens made of plastic material collecting beams emitted from the first and second light sources to an information recording plane; and a diaphragm is provided a plurality of ring-shaped zones in effective diameter area on at least one plane of the objective lens, at the time of conducting recording or reproducing information of the first optical information recording medium, aberration compensating of the beams from the diffraction section is performed in the effective diameter area to make which less than diffraction limit; at the time of conducting recording or reproducing information of the second optical information recording medium, aberration compensating of the beams in area of a spherical aberration discontinuous portion at the point h in the effective diameter area where a spherical aberration-stepped amount is 7 mum to 40 mum is performed to make which less than diffraction limit.

Description

technical field [0001] The present invention relates to the following objective lens, which is formed of plastic, and is used in an optical readout device, which uses a light beam emitted from a laser to pass through the objective lens and on the information recording surface by means of a transparent substrate of an optical information recording medium , forming light spots, optically recording and / or reproducing information, the present invention particularly relates to following objective lens, this objective lens adopts wavelength λ in recording and / or reproducing of the 1st optical information recording medium 1 The first light source of the second optical information recording medium uses a wavelength λ for recording and / or reproduction 2 The second light source, through diffraction, due to the thickness t of the transparent substrate of the first optical information recording medium 1 and the transparent substrate thickness t of the second optical information recording...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G11B7/12G11B7/135G02B3/08G02B5/18G02B13/00G02B13/18G11B7/00G11B7/125G11B7/1275G11B7/1353G11B7/1374G11B7/1392
CPCG11B7/1353G11B7/13922G11B7/1374G11B2007/0006G11B7/1275
Inventor 齐藤真一郎坂本胜也
Owner KONICA CORP