Unlock instant, AI-driven research and patent intelligence for your innovation.

Objective lens, optical pickup device, and recording and/or reproducing apparatus for optical recording medium

A technology of optical recording medium and optical pickup device, which is applied in the direction of recording/reproducing by optical method, optical recording head, beam guiding device, etc. The effect of improving cost reduction and achieving manufacturing efficiency

Inactive Publication Date: 2009-06-10
FUJI PHOTO OPTICAL CO LTD
View PDF2 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

And, on the one hand, because this objective lens is the special shape that the convex surface of strong curvature faces the light source side, and manufacturability deteriorates easily, moreover, it is difficult to ensure working distance sufficiently, therefore, also demand to have the tool that can solve this kind of problem. constitute
[0013] That is, in the objective lens described in each of the above-mentioned patent documents, it is not necessarily possible to make a structure that can take into account both small size and light weight, and good manufacturability and ensuring working distance. Always wanted to improve from this view

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Objective lens, optical pickup device, and recording and/or reproducing apparatus for optical recording medium
  • Objective lens, optical pickup device, and recording and/or reproducing apparatus for optical recording medium
  • Objective lens, optical pickup device, and recording and/or reproducing apparatus for optical recording medium

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0124] The objective lens 8 of embodiment 1 is made of glass single lens, as figure 1 As shown, the surface 8a on the light source side is a convex surface with a large curvature (that is, a large curvature), and the surface 8b on the optical recording medium side is a concave surface (on the optical axis) with a small curvature (that is, a small curvature).

[0125] In addition, both surfaces of the objective lens 8 in this embodiment are aspherical.

[0126] This objective lens 8 is a lens that sets the numerical aperture NA to 0.85 for the light of the wavelength λ404.7nm used as the light and satisfactorily converges it on the optical recording layer 10 of the optical recording medium (Blu-ray Disc) 9 . In addition, the thickness t of the protective layer of this optical recording medium 9 was set to 0.1000 mm.

[0127] In the upper part of the following Table 1, as the specific numerical values ​​of the lens data of the objective lens 8 related to this Example 1, the cur...

Embodiment 2

[0171] The objective lens 8 of embodiment 2 is made of glass single lens, as figure 2 As shown, the surface 8a on the light source side is a convex surface with a large curvature, and the surface 8b on the optical recording medium side is a concave surface with a small curvature (on the optical axis).

[0172] In addition, both surfaces of the objective lens 8 in this embodiment are aspherical.

[0173] The objective lens 8 is a lens that sets the numerical aperture NA to 0.85 for light having a wavelength λ of 404.7 nm as the used light and satisfactorily converges on the optical recording layer 10 of the optical recording medium (Blu-ray Disc) 9 . In addition, the thickness t of the protective layer of this optical recording medium 9 was set to 0.1000 mm.

[0174] In the upper part of the following Table 2, as specific numerical values ​​of the lens data of the objective lens 8 according to the second embodiment, the radius of curvature R (mm), the surface distance D (mm),...

Embodiment 3

[0216] The objective lens 8 of embodiment 3 is made of plastic single lens, as image 3 As shown, the surface 8a on the light source side is a convex surface with a large curvature, and the surface 8b on the optical recording medium side is a convex surface with a small curvature (on the optical axis).

[0217] In addition, both surfaces of the objective lens 8 in this embodiment are aspherical.

[0218] The objective lens 8 is a lens that sets the numerical aperture NA to 0.85 for light having a wavelength λ of 408.0 nm as the used light and satisfactorily converges on the optical recording layer 10 of the optical recording medium (Blu-ray Disc) 9 . In addition, the thickness t of the protective layer of this optical recording medium 9 was set to 0.1000 mm.

[0219] In the upper part of the following Table 3, as the specific numerical values ​​of the lens data of the objective lens 8 related to this Example 3, the radius of curvature R (mm), the surface distance D (mm), and ...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
wavelengthaaaaaaaaaa
thicknessaaaaaaaaaa
Login to View More

Abstract

The invention provides an objective lens (8) which consists of a single lens element. A light source side surface (8a) is formed into a convex surface having a large curvature, and an optical recording medium side surface (8b) has a small curvature. Also, the objective lens satisfies the following expressions (1) and (2); [Phi]A / [Phi]B is not more than 5.0 (1); ([Phi]A / [Phi]B+19.33*bf' / f') is not less than 7.69 but not more than 9.45, where [Phi]A denotes an effective diameter (mm) of the light source side surface of the objective lens (8), [Phi]B denotes an effective diameter (mm) of the optical recording medium side surface of the objective lens (8), bf' denotes a back focal length (mm) of the objective lens (8), and f' denotes a focal length (mm) of the objective lens (8).

Description

technical field [0001] The present invention relates to an objective lens, an optical pick-up device, and an optical recording medium recording and / or reproducing device capable of efficiently converging light used on an optical recording medium when recording or reproducing information. Short-wavelength light is used as an objective lens used for recording / reproducing a high-density optical recording medium using light, an optical pickup device, and an optical recording medium recording and / or reproducing device. Background technique [0002] In recent years, various optical recording media such as DVD (Digital Versatile Disc) and CD (Compact Disc. Including -ROM, -R, -RW) have been used for various purposes. The demand for increasing the recording capacity of the optical recording medium becomes stronger. In order to increase the recording capacity of an optical recording medium, it is known that shortening the wavelength of light used as a light source and increasing the...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): G02B13/00G02B13/18G11B7/135
CPCG11B7/1374
Inventor 胜间敏明森将生小里哲也北原有
Owner FUJI PHOTO OPTICAL CO LTD