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Optical pickup device-use optical element, coupling lens and optical pickup device

A technology of optical pickup and relay lens, which is applied in the direction of light beam guiding device, optical recording/reproduction, optical recording head, etc., which can solve the problems of not considering the diffraction efficiency and the inability to ensure the luminous flux of the light spot, etc.

Inactive Publication Date: 2009-09-09
KONICA MINOLTA OPTO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Yet, although above-mentioned patent document 1 is provided with the optical pick-up device of diffractive structure to object lens, disclose, because do not consider diffraction efficiency on the diffractive structure used, so also exist can not guarantee optimum light spot luminous flux Happening

Method used

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  • Optical pickup device-use optical element, coupling lens and optical pickup device
  • Optical pickup device-use optical element, coupling lens and optical pickup device
  • Optical pickup device-use optical element, coupling lens and optical pickup device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0286] Table 1 shows lens data of an optical element (objective lens) as an example suitable for the above-mentioned embodiment. As can be seen from Table 1, in the objective lens, a diffraction structure is provided in a region (referred to as a common region) where light beams from the first semiconductor laser, the second semiconductor laser, and the third semiconductor laser pass. In addition, if a change occurs in which the wavelength of the light source becomes longer, the diffractive structure has an optical characteristic that makes spherical aberration more insufficient in the light beam passing through the diffractive structure. This embodiment corresponds to the optical elements described in items 6 and 7. Here, hereafter (including the lens data of the table), it is stipulated that E (for example, 2.5×E-3) represents a power multiplier of 10 (for example, 2.5×10 -3 ).

[0287]

[0288] The specifications of this embodiment are as follows:

[0289] (1) Light s...

Embodiment 2

[0299] Table 2 shows lens data of an optical element (objective lens) as an example suitable for the above-mentioned embodiment. As can be seen from Table 2, in the objective lens, a diffraction structure is provided in a region (referred to as a common region) where light beams from the first semiconductor laser, the second semiconductor laser, and the third semiconductor laser pass. In addition, if a change occurs in which the wavelength of the light source becomes longer, the diffractive structure has an optical characteristic that makes spherical aberration more insufficient in the light beam passing through the diffractive structure. This embodiment corresponds to the optical element described in Item 11.

[0300]

[0301] Aspheric coefficient

[0302]

[0303] The specifications of this embodiment are as follows:

[0304] (1) Light source wavelength λ1 of the first semiconductor laser: 407nm

[0305] (2) The number n1(n1A) of the maximum diffraction efficiency w...

Embodiment 3

[0314] Table 3 shows lens data of an optical element (objective lens) as an example suitable for the above-mentioned embodiment. As can be seen from Table 3, in the objective lens, a diffraction structure is provided in a region (referred to as a common region) where light beams from the first semiconductor laser, the second semiconductor laser, and the third semiconductor laser pass. In addition, if a change occurs in which the wavelength of the light source becomes longer, the diffractive structure has an optical characteristic that makes spherical aberration more insufficient in the light beam passing through the diffractive structure. This embodiment corresponds to the optical element described in Item 11.

[0315]

[0316] The specifications of this embodiment are as follows:

[0317] (1) Light source wavelength λ1 of the first semiconductor laser: 407nm

[0318] (2) The number n1(n1A) of the maximum diffraction efficiency when the light beam from the first semicondu...

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Abstract

Since the diffraction structure of an object lens (16) has optical characteristics in which when a light-source wavelength changes to be longer, a spherical aberration at a light flux passed through such a diffraction structure is reduced, a spherical aberration can be more favorably corrected for a change in refractive index of an object lens with a change in temperature and a change in wavelength of a light source with a change in temperature. In addition, when 1.1 >= (n1 x lambda1) / (n3 x lambda3) >= 0.9 is satisfied, the quantity of light of a diffraction light flux applied to the information recording surface of a high-density DVD via the diffraction structure of the object lens (16) and the quantity of light of a diffraction light flux applied to the information recording surface of a CD are increased to effectively restrict information writing errors and reading errors.

Description

technical field [0001] The present invention relates to an optical element for an optical pickup device, a relay lens, and an optical pickup device, and particularly relates to recording information on three different optical information recording media by using light beams emitted from three light sources with different wavelengths of the light sources and / or reproduced optical elements for optical pickup devices, relay lenses, and optical pickup devices. Background technique [0002] In recent years, along with the practical use of short-wavelength red semiconductor lasers, people have developed and commercialized high-capacity lasers with the same size and capacity as CDs (Compact Disks), which are conventional optical disks (also called optical information recording media). DVD (Digital Versatile Disc), which is a high-density optical disc, can be expected to debut with a higher-density next-generation optical disc in the near future. In the condensing optical system o...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G11B7/135G11B7/1353G11B7/1374G11B7/1378G11B7/139G11B7/1392
Inventor 池中清乃
Owner KONICA MINOLTA OPTO