Optical pick device

An optical and optical disc technology, applied in the field of optical pickup devices, can solve problems such as narrow chromatic aberration

Inactive Publication Date: 2005-07-20
JVC KENWOOD CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In addition, the corresponding wavelength range is about ±5 to ±10nm, which is narrower than the above-mentioned axial chromatic aberration

Method used

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Embodiment Construction

[0055] Embodiments of the optical pickup device of the present invention will be described in detail below with reference to the accompanying drawings.

[0056] figure 1 It is a schematic diagram showing the configuration of the optical pickup device.

[0057] Optical pick-up device 10 irradiates light along the track (track) of rotating optical disc 101, carries out recording or playback of information signal, has laser diode 11 as light source; The parallelism of the emitted light changes; the objective lens 19 converges the light emitted from the beam expander 18 along the track of the above-mentioned optical disc 101 for irradiation. The beam expander 18 is made of a concave lens 16 and a Fresnel lens (Fresnel lens) 17 that forms a diffractive surface on one surface of a flat plate.

[0058] f 1 =((λ 2 / λ 1 )-1)f 0 v 0

[0059] f 2 =(1-(λ 2 / λ 1 ))b

[0060] Then the focal length of the Fresnel lens 17 satisfies at fn

[0061] f 1 n 2

[0062] range.

[006...

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Abstract

Disclosed is such an optical pickup controlling an aberration even if optical axes of an objective lens and another optical system are shifted from each other. The optical pickup is a device for recording or reproducing an information signal by irradiating light along a track of a rotating optical disk, including a light source, a beam expander for changing a parallelism of light emitted from the light source, and an objective lens 33 for collecting the light emitted from the beam expander along the track of the optical disk and for irradiating the collected light thereonto, wherein the beam expander is comprised of a concave lens 31 and a Fresnel lens 32, and a focal distance fn of the diffraction lens exists in a range satisfying the following inequality: f1 G11B 7 / 135 5 20 1 2003 / 3 / 11 1445765 2003 / 10 / 1 1211791 2005 / 7 / 20 2005 / 7 / 20 2005 / 7 / 20 Victor Co. of Japan Ltd. Japan Ito Chosei xie lina guan zhaohui 11219 Japan 2002 / 3 / 18 074686 / 2002

Description

technical field [0001] The invention relates to an optical pick-up device, which irradiates light on an optical disc to record and reproduce information signals. Background technique [0002] Conventionally, optical discs as optical recording media have been used to store information signals (data) such as video, audio, and data for computers. In addition, such optical discs are popular because of their good mass-producibility and low cost. For such optical discs, there is a strong demand for higher density and larger capacity of information signals recorded on the optical discs, and such demands have become stronger in recent years. [0003] In order to increase the recording density of the information signal recorded on the optical disc, the following two methods are effective, that is, shortening the wavelength of the light beam used to read the information signal, and using a lens with a large numerical aperture (NA) as a The objective lens converges on the disc. [0...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G02B5/18G02B13/00G02B13/18G11B7/135G11B7/1353G11B7/1372G11B7/1378G11B7/1392G11B7/1398
CPCG11B2007/13722G11B7/1378G11B7/13922G11B7/1398G11B7/1353
Inventor 糸长诚
Owner JVC KENWOOD CORP
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