WO2004036567A1 - 光ピックアップ装置用の光学素子、カップリングレンズ及び光ピックアップ装置 - Google Patents
光ピックアップ装置用の光学素子、カップリングレンズ及び光ピックアップ装置 Download PDFInfo
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- WO2004036567A1 WO2004036567A1 PCT/JP2003/013224 JP0313224W WO2004036567A1 WO 2004036567 A1 WO2004036567 A1 WO 2004036567A1 JP 0313224 W JP0313224 W JP 0313224W WO 2004036567 A1 WO2004036567 A1 WO 2004036567A1
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- wavelength
- pickup device
- information recording
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Classifications
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
- G11B7/1353—Diffractive elements, e.g. holograms or gratings
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/18—Diffraction gratings
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/125—Optical beam sources therefor, e.g. laser control circuitry specially adapted for optical storage devices; Modulators, e.g. means for controlling the size or intensity of optical spots or optical traces
- G11B7/127—Lasers; Multiple laser arrays
- G11B7/1275—Two or more lasers having different wavelengths
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
- G11B7/1365—Separate or integrated refractive elements, e.g. wave plates
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
- G11B7/1372—Lenses
- G11B7/1374—Objective lenses
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
- G11B7/1372—Lenses
- G11B7/1378—Separate aberration correction lenses; Cylindrical lenses to generate astigmatism; Beam expanders
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
- G11B7/139—Numerical aperture control means
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
- G11B7/1392—Means for controlling the beam wavefront, e.g. for correction of aberration
- G11B7/13922—Means for controlling the beam wavefront, e.g. for correction of aberration passive
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B2007/0003—Recording, reproducing or erasing systems characterised by the structure or type of the carrier
- G11B2007/0006—Recording, reproducing or erasing systems characterised by the structure or type of the carrier adapted for scanning different types of carrier, e.g. CD & DVD
Definitions
- the present invention relates to an optical element, a coupling lens, and an optical pickup device for an optical pickup device, and particularly to three different optical information recording media using light beams emitted from three light sources having different light source wavelengths.
- the present invention also relates to an optical element, a coupling lens, and an optical pickup device for an optical pickup device capable of recording and / or reproducing information.
- an optical disk that performs information recording / reproducing with a specification of NAO.85 and a light source wavelength of 405 nm is a DVD (NA0.6, light source wavelength It is possible to record 20 to 30 GB of information per side on an optical disc with a diameter of 12 cm which is the same size as 650 nm and a storage capacity of 4, 7 GB.
- a condensing optical system provided with a diffractive structure has been developed so that an appropriate condensing spot can be formed on the information recording surface of a high-density DVD (see Patent Document 1).
- Patent Document 1 Although an optical pickup device having a diffraction structure provided on an objective lens is disclosed, the diffraction efficiency is not taken into consideration in such a diffraction structure. In some cases, it could not be secured. Disclosure of the invention
- the present invention has been made in view of the above-described problems, and appropriately records and / or reproduces information on, for example, all high-density DVDs and conventional DVDs and CDs while ensuring a sufficient spot light amount. It is an object of the present invention to provide an optical element, a coupling lens, and an optical pickup device for an optical pickup device capable of performing the above.
- the optical element for an optical pickup device includes a first light source having a wavelength of I1, a second light source having a wavelength ⁇ 2 ( ⁇ 1 ⁇ 2), and a wavelength 3 (1.6 ⁇ 1 ⁇ ⁇ 3 ⁇ 2.0 ⁇ ⁇ 1 and; I 2 ⁇ 3), and a condensing optical system including an optical element, wherein the condensing optical system is configured to receive light from the first light source.
- a condensing optical system including an optical element, wherein the condensing optical system is configured to receive light from the first light source.
- the light flux from the second light source is condensed on the information recording surface of the second optical information recording medium via a protective layer having a thickness t 2 (0.8 t 1 ⁇ t 2 ⁇ 1.2 t 1). By doing so, it is possible to record and / or reproduce information, and furthermore, the light flux from the third light source is converted to a thickness t 3 (1.9 t 1 ⁇ t 3 ⁇ 2. 1 ⁇ t 1) Focused on the information recording surface of the third optical information recording medium through the protective layer In the optical element for an optical pickup device which is capable of recording and / or reproducing information,
- a diffractive structure is provided on at least one surface of the optical element, and performs recording and / or reproduction on the first optical information recording medium, the second optical information recording medium, and the third optical information recording medium, respectively.
- the first light source, the second light source, and the third light source The illuminated beams respectively pass through the diffraction structure in common, and then, on the information recording surfaces of the first optical information recording medium, the second optical information recording medium, and the third optical information recording medium. Each is condensed to form a spot,
- the orders of the diffracted light beams having the highest diffraction efficiency among the diffracted light beams generated by the diffraction structure are nl and ⁇ , respectively. 3 (nl, ⁇ 3 is a natural number)
- the optical element according to the above item 1 by satisfying the expression (1), the light amount of the diffracted light beam irradiated to the information recording surface of the first optical information recording medium via the diffractive structure of the optical element and the light amount Writing of information because the amount of diffracted light beam irradiated on the information recording surface of the third optical information recording medium is higher [( ⁇ ⁇ ⁇ ⁇ ) / ( ⁇ 3 X ⁇ 3) is closer to 1] The occurrence of errors and reading errors can be effectively suppressed.
- FIG. 1 is a diagram showing whether the aberration characteristic is under or over.
- FIG. 2 shows an optical information recording / reproducing device or optical device according to the first embodiment.
- FIG. 3 shows an optical information recording / reproducing device or optical device according to the second embodiment.
- FIG. 4 shows an optical information recording / reproducing device or optical device according to the third embodiment.
- FIG. 5 shows an optical information recording / reproducing device or optical device according to the fourth embodiment. It is a schematic structure figure of an apparatus.
- FIG. 6 shows an optical information recording / reproducing apparatus or optical device according to the fifth embodiment.
- FIG. 7 shows an optical information recording / reproducing device or optical device according to the sixth embodiment.
- FIG. 8 shows an optical information recording / reproducing device or optical device according to a seventh embodiment.
- FIG. 9 shows an optical information recording / reproducing device or optical device according to the eighth embodiment.
- FIG. 10 is a schematic configuration diagram of an optical information recording / reproducing device or an optical pickup device according to the ninth embodiment.
- FIG. 11 is a schematic configuration diagram of an optical information recording / reproducing apparatus or an optical pickup apparatus according to the tenth embodiment.
- FIG. 12 is a schematic configuration diagram of an optical information recording / reproducing apparatus or an optical pickup apparatus according to the eleventh embodiment.
- FIG. 13 is a schematic configuration diagram of an optical information recording / reproducing device or an optical pickup device according to the 12th embodiment.
- FIG. 14 is a longitudinal spherical aberration diagram relating to the diffracted light of the order having the maximum diffraction efficiency when a light beam for high-density DVD passes through the objective lens of the example.
- FIG. 15 is a longitudinal spherical aberration diagram relating to the diffracted light of the order having the maximum diffraction efficiency when the DVD light beam passes through the objective lens of the example.
- FIG. 16 is a longitudinal spherical aberration diagram relating to the diffracted light of the order having the maximum diffraction efficiency when the light beam for CD passes through the objective lens of the example.
- FIG. 17 is a schematic diagram showing a first region and a second region of the optical element.
- optical element for an optical pickup device 4, wherein in the optical element according to item 2 or 3, when an optical system magnification of the optical element with respect to the light beam having the wavelength 3 is m3,
- the protective layers of the first and second optical information recording media and the third optical information The difference in spherical aberration due to the difference in thickness and wavelength from the protective layer of the recording medium and the difference in wavelength can be appropriately adjusted by causing the light beam from the third light source to enter the optical element as a divergent light beam according to equation (4). It can be corrected quickly.
- Item 5 The optical element for an optical pickup device according to Item 5, wherein the optical element according to Item 2 or 3, wherein an optical system magnification of the optical element with respect to the light flux of the wavelength; 3 is m3,-1/1 2. It is more preferable that 0 ⁇ m3 ⁇ -1/1 3.4 (4,).
- Item 6 The optical element for an optical pickup device according to Item 6, wherein the optical element according to any one of Items 2 to 5 is generated by the diffraction structure when the light flux of the wavelength I2 is incident on the optical element. Assuming that the order of the diffracted light beam having the highest diffraction efficiency in the diffracted light is n 2 (n 2 is a natural number),
- ( ⁇ 2 X 2) can take various values, but the so-called 2 laser 1 package, which is the second light source and the third light source that are currently in practical use, are arranged on the same substrate.
- the optical system magnification of the optical element with respect to the light beam of the wavelength ⁇ 2 can be made equal to the optical system magnification of the optical element with respect to the light beam of the wavelength ⁇ 3. I have to.
- optical element for an optical pickup device wherein the optical element according to Item 6, wherein an optical system magnification of the optical element with respect to the light beam of the wavelength ⁇ 2 is m2.
- Item 8 The optical element for an optical pickup device according to Item 8, wherein the optical element according to Item 6, wherein an optical system magnification of the optical element with respect to the light flux of the wavelength; 2 is m2.
- Item 9 The optical element for an optical pickup device according to Item 9, wherein the optical element according to Item 7 or 8, wherein the second light source that emits the light beam of the wavelength 2 and the third light source that emits the light beam of the wavelength ⁇ 3. If the light source is cut and the light source is a cut light source such as a so-called two-laser one-package, the size of the optical pickup device can be reduced.
- the light source is formed into a jet refers to a configuration in which, for example, two light sources are mounted and integrated on the same substrate, but is not limited thereto.
- Item 10 The optical element for an optical pickup device according to Item 10, wherein the optical element according to any one of Items 2 to 5, wherein the light beam having the wavelength: 2 is incident on the optical element.
- ⁇ 2 (where ⁇ 2 is a natural number) be the order of the diffracted light beam having the highest diffraction efficiency among the diffracted light generated by
- the optical element for an optical pickup device described in Item 11 is described in Item 3, 4, 5, or 10.
- L2 is m2
- Item 12 The optical element for an optical pickup device according to Item 12, wherein in the optical element according to Item 7, 8, or 11, when the diffractive structure changes so that the light source wavelength becomes longer, the light passes through the diffractive structure. It has optical characteristics that make the spherical aberration lower in the light beam. When the diffractive structure changes so that the wavelength of the light source becomes longer, the diffractive structure has optical characteristics that make the spherical aberration lower in the light beam passing through the diffractive structure.
- the optical element for an optical pickup device according to Item 13 is the optical element according to Item 11 or 12, wherein the first light source that emits the light beam of the wavelength 1 and the light of the wavelength; I2. If the emitting second light source is unitized, the optical pickup device can be made compact.
- the optical element for an optical pickup device is preferably an objective lens in the optical element according to any of items 2 to 13, but is not limited thereto.
- Item 15. The optical element for an optical pickup device according to Item 15, wherein the optical element according to any one of Items 1 to 14, wherein at least one optical surface of the optical element is the first optical information recording medium, The wavelengths respectively radiated from the first light source, the second light source, and the third light source to perform recording and Z or reproduction on the second optical information recording medium and the third optical information recording medium, respectively.
- the wavelengths emitted from the first light source and the second light source, respectively; the forces that allow the light fluxes of I1 and 2 to pass through; the wavelengths emitted from the third light source; the dichroic coat that does not allow the light flux of I3 to pass through The third optical information It can record and ⁇ or reproducing information properly for recording medium. (See Fig. 17)
- the optical element for an optical pickup device according to Item 16 is the optical element according to Item 15, wherein a diffractive structure is not provided on the optical surface on which the dichroic coat is applied. The cause of uneven coating can be reduced.
- Item 17 The optical element for an optical pickup device according to Item 17, wherein the optical element according to any one of Items 1 to 14, wherein at least one optical surface of the optical element is the first optical information recording medium, The wavelengths respectively radiated from the first light source, the second light source, and the third light source to perform recording and reading or reproduction on the second optical information recording medium and the third optical information recording medium, respectively.
- a first diffraction structure is provided in the first region, a second diffraction structure is provided in the second region, and a wavelength generated by the first diffraction structure;
- the order of the diffracted light having the highest diffraction efficiency is defined as n 1 A
- the order of the diffracted light having the highest diffraction efficiency among the diffracted lights of the second wavelength generated by the first diffraction structure is represented by n.
- the numerical aperture NA for recording and / or reproducing information on and from the third optical information recording medium is defined as the numerical aperture for recording and / or reproducing information for other optical information recording media.
- a configuration is necessary in which the numerical aperture NA is reduced when the third optical information recording medium is used.
- equation (9) is satisfied.
- the combination of the order having the maximum diffraction efficiency that occurs when light of wavelengths I 1, ⁇ 2, and ⁇ 3 It is necessary to change the optical system magnification of the objective optical element.
- the optical system magnification of the objective optical element for each light is the same in the first region and the second region, but the combination of diffraction orders is changed, so that the wavelength passing through the second region; Spherical aberration can be imparted to the diffracted light having the maximum diffraction efficiency, so that no light is collected on the information recording surface of the third optical information recording medium, thereby obtaining an effect of reducing the numerical aperture.
- Item 18 The optical element for an optical pickup device according to Item 18, wherein in the optical element according to any one of Items 1 to 14, at least one optical surface of the optical element is the first light.
- the first light source, the second light source, and the third light source are used.
- a first region through which light beams having the respective wavelengths I 1, ⁇ 2 and I 3 illuminated are transmitted, and recording and / or reproducing information with respect to the first optical information recording medium and the second optical information recording medium, respectively.
- the light fluxes of the wavelengths ⁇ 1 and I 2 emitted from the first light source and the second light source, respectively, are passed through and condensed on the information recording surface, but the wavelength ⁇ emitted from the third light source is A second region that is not focused on the information recording surface even when the light beam of 3 passes therethrough, wherein a first diffraction structure is provided in the first region, and a second diffraction structure is provided in the second region.
- n 1 A the order of the diffracted light having the maximum diffraction efficiency of the wavelengths generated by the first diffraction structure
- Wavelength generated by the diffractive structure; of the 1 diffracted light, the order of the diffracted light having the highest diffraction efficiency is defined as ⁇ 2 ⁇ , and the wavelength generated by the second diffractive structure
- the present optical element satisfies the expression (10), if the wavelength ⁇ 3 is twice the wavelength 1, the wavelength passing through the second diffraction structure; I 1 Assuming that the order of the maximum diffraction efficiency in the light beam of the above is ⁇ 2 ⁇ , the maximum diffraction efficiency of the light beam of the wavelength ⁇ 3 that has passed through the second diffraction structure is the order ⁇ 2 A / 2, so that the order ⁇ 2 If ⁇ is an even number, it becomes impossible to impart spherical aberration to the diffracted light having the maximum diffraction efficiency in the light beam of wavelength 3 passing through the second region.
- n 2 A is an odd number
- the diffraction efficiency of an integer order close to n 2 AZ 2 increases. That time Since the folded light is not condensed, the light having the wavelength ⁇ 3 that has passed through the second diffraction structure is not efficiently condensed on the information recording surface of the third optical information recording medium, and the numerical aperture ⁇ ⁇ ⁇ can be reduced.
- Item 21 The optical element for an optical pickup device according to Item 18, wherein the maximum diffraction efficiency of the diffracted light of wavelength ⁇ 3 generated by the second diffraction structure is 60 in the optical element according to Item 18. % Or less, information can be appropriately recorded and / or reproduced on the third optical information recording medium.
- Item 22 The optical element for an optical pickup device according to Item 22, wherein the optical element according to any one of Items 18 to 21 performs color correction on the light beam of the first wavelength. Wavelength; If the combination of diffraction orders having the highest diffraction efficiency that occurs when light of I 1 and ⁇ 2 is incident is different between the first and second diffraction structures, use the paraxial power of diffraction. It is necessary to match the condensing position of the diffracted light passing through each area. On the other hand, if the expression (10) is satisfied, color correction can be performed on the luminous flux of the wavelength; 1 or 2 using the paraxial power of diffraction. Information can be recorded and / or reproduced on an information recording medium more appropriately.
- the optical pickup device comprises: a first light source having a wavelength of 1; and a wavelength ⁇ 2 ⁇ 1 ⁇ 2), a third light source with wavelength ⁇ 3 (1.6 ⁇ ⁇ 1 ⁇ 3 ⁇ 2.0-X 1 and ⁇ 2 ⁇ ⁇ 3), and condensing optics including optical elements
- the light-collecting optical system focuses the light beam from the first light source on the information recording surface of the first optical information recording medium via the protective layer having a thickness of t1.
- the luminous flux from the second light source has a thickness t 2 (0.8 ⁇ t 1 ⁇ t 2 ⁇ 1.2 ⁇ t 1
- the light is condensed on the information recording surface of the second optical information recording medium via the protective layer of (2), whereby information can be recorded and / or reproduced, and the light flux from the third light source can be obtained.
- An optical pickup that can perform recording and Z or playback In the backup device,
- a first diffractive structure is provided on at least one surface of the optical element, and the first optical information recording medium, the second optical information recording medium, and the third optical information recording medium are respectively recorded and read.
- the light fluxes respectively emitted from the first light source, the second light source, and the third light source pass through the first diffraction structure in common, and then the first optical information recording is performed.
- the optical pickup device according to item 24 is the optical pickup device according to item 23,
- the orders nl and n3 are
- the operational effects of the present optical pickup device are the same as those of the optical pickup device described in Item 2.
- Item 25 is the optical pickup device according to Item 24, wherein an optical system magnification of the optical element with respect to the light beam of the wavelength ⁇ 1 is ml.
- Item 26 is the optical pickup device according to Item 24 or 25, wherein the optical system magnification of the optical element with respect to the light flux of the wavelength; I3 is m3.
- Item 27 is the optical pickup device according to Item 24 or 25, wherein the optical system magnification of the optical element with respect to the light flux of the wavelength; I3 is m3.
- Item 28 is the optical pickup device according to any one of Items 24 to 27, wherein a diffraction beam generated by the first diffraction structure when the light beam of the wavelength ⁇ 2 enters the optical element. Assuming that the order of the diffracted light beam having the highest diffraction efficiency is ⁇ 2 ( ⁇ 2 is a natural number), (n 2 X ⁇ 2) / (n 3 X ⁇ 3) ⁇ 1 (5). The operational effects of the present optical pickup device are the same as those of the optical pickup device described in Item 6.
- Item 29 is the optical pickup device according to Item 28, wherein an optical system magnification of the optical element with respect to the light flux of the wavelength ⁇ 2 is m2.
- Item 30 is the optical pickup device according to Item 28, wherein the optical system magnification of the optical element with respect to the light flux of the wavelength 2 is m2.
- Item 31 is the optical pickup device according to Item 30, wherein the second light source that emits the light beam of wavelength 2 and the third light source that emits light of wavelength 3 are unitized. I have. The operation and effect of this optical pickup device are the same as those of the optical pickup device described in Item 9.
- Item 32 The optical pickup device according to any one of Items 24 to 27, wherein the optical pickup device according to any one of Items 24 to 27 includes a diffraction element generated by the first diffraction structure when the light beam of the wavelength ⁇ 2 enters the optical element. Assuming that the order of the diffracted light beam having the highest diffraction efficiency is ⁇ 2 ( ⁇ 2 is a natural number),
- Item 33 is the optical pickup device according to Item 25, 26, 27 or 32, wherein the optical system magnification of the optical element with respect to the light beam of the wavelength ⁇ 2 is m2.
- Item 34 is the optical pickup device according to Item 29, 30 or 33, wherein, when the first diffraction structure changes so that the light source wavelength becomes longer, the diffraction structure It has optical characteristics that make the spherical aberration of the light beam passing through the lens lower.
- the operational effects of the present optical pickup device are the same as those of the optical pickup device described in [12].
- Item 35 is the optical pickup device according to Item 33 or 34, wherein the first light source that emits the light beam of the wavelength 1 and the light of the wavelength; I2 are emitted.
- the second light source is unitized.
- the operation and effect of this optical pickup device are the same as those of the optical pickup device described in Item 13.
- Item 36 is the optical pickup device according to any one of Items 24 to 35, wherein the optical element is an objective lens.
- Item 37 is the optical pickup device according to any one of Items 23 to 31, wherein the light beam of the wavelength; I2 is incident on the optical element as a divergent light beam.
- a coupling lens is disposed between the second light source and the optical element.
- the optical pickup device described in Item 38 is compatible with the optical pickup device described in Item 37. Then, with the position corresponding to the numerical aperture NAD when recording and / or reproducing information on the second optical information recording medium as a boundary, the optical surface of the coupling lens is defined as an inner area close to the optical axis. When divided into an outer region far from the optical axis, the luminous flux of the wavelength; I2 has a different divergence angle between when passing through the inner region and when passing through the outer region.
- the thickness of the protective layer in the optical information recording medium is different, if the magnification of the objective lens at the time of recording and / or reproducing information on each optical information recording medium is the same, a protective layer having a different thickness is provided.
- Spherical aberration occurs at the converging spot on the information recording surface of the optical information recording medium.
- the divergence angle is changed to form an appropriate condensed spot.For example, one is an infinite light beam and the other is a finite light beam. Is made to be incident.
- both of the sine conditions cannot be satisfied. If finite light is incident on an objective optical element that does not satisfy the sine condition, if there is an optical axis misalignment between the objective optical element and another optical element due to assembly accuracy problems or tracking, etc. Coma aberration that cannot be ignored may occur.
- the objective optical element (objective Lens) 1 6 can be corrected in the case where is shifted in a direction perpendicular to the optical axis. That is, if there is no optical axis misalignment between the objective optical element and the coupling lens, the light flux of the wavelength; L2 does not contribute to the inside of the focused spot when passing outside the effective diameter.
- the objective optics can be passed through, for example, outside the effective diameter of the cutting lens.
- the light beam incident within the effective diameter of the element causes significant deterioration in aberration on the information recording surface, and inhibits appropriate information recording and Z or reproduction. Therefore, by using the above-mentioned force-coupling lens, it is possible to prevent the light beam passing outside the effective diameter from being condensed on the information recording surface, and to pass only the area where the effective diameter of the objective optical element and the effective diameter of the coupling lens overlap. It is possible to appropriately record and / or reproduce information using a light beam with less aberration deterioration.
- the light beam having a wavelength of I1 is incident on the objective optical element as an infinite light beam, even if the coupling lens is provided as described above, there is no adverse effect on the recording and Z or reproduction of information on the first optical information recording medium. Absent.
- Item 39 is the optical pickup device according to Item 38, wherein the divergence angle of the light beam of the wavelength L2 passing through the outer region and the light beam L2 passing through the inner region is Since the wavelength is larger than the divergence angle of the light beam of I 2, the above-mentioned effect can be more effectively exerted.
- Item 40 is the optical pickup device according to any one of Items 37 to 39, wherein the light beam of the wavelength 3 is incident on the optical element after passing through the coupling lens. Therefore, the configuration of the optical pickup device can be simplified.
- Item 41 is the optical pickup device according to Item 40, wherein the aperture for recording and / or reproducing information on the third optical information recording medium is provided.
- the optical surface of the coupling lens When the optical surface of the coupling lens is divided into an inner area close to the optical axis and an outer area far from the optical axis with a position corresponding to a number NAC as a boundary, the light beam of the wavelength ⁇ 3 Since the divergence angle is different between when the light beam passes through the outer region and when the light beam passes through the outer region, more appropriate information can be obtained even when the light beam of wavelength 3 is incident on the objective optical element in a finite light beam state. Recording and / or playback can be performed.
- the diffraction structure is provided in at least one of the inner region and the outer region of the power coupling lens in the optical pickup device described in any one of Items 38 to 41. The above-described operation can be realized.
- the optical pickup device described in Item 43 corresponds to the numerical aperture NAD when recording and / or reproducing information on the second optical information recording medium in the optical pickup device described in Item 37.
- the optical surface of the coupling lens is divided into an inner area close to the optical axis and an outer area far from the optical axis, a dichroic coat that does not allow the light flux of the wavelength;
- the optical surface of the optical element is positioned close to the optical axis with a position corresponding to the numerical aperture NAD when recording and / or reproducing information on the second optical information recording medium as a boundary applied to the outer region.
- a dichroic coat that does not allow the light beam of the wavelength ⁇ 2 to pass is applied to the outer region, so that an effective diameter corresponding to the numerical aperture NAD of the objective optical element is provided.
- Katsu Pringle With less light flux aberration deterioration effective diameter corresponding to numerical aperture NAD of the figure it passes through only a region where the polymerization, it is possible to perform recording and / or reproducing information properly.
- the phrase “not allow the light beam to pass” means that the light transmission amount is reduced (including zero light transmission amount) so as not to affect the recording and Z or reproduction of information.
- Item 44 is the optical pickup device according to Item 37, wherein a power coupling lens is arranged between the third light source and the optical element.
- the optical surface of the coupling lens is set to an inner area close to the optical axis with a boundary corresponding to a numerical aperture NAC when recording and / or reproducing information Z or reproduction on the third optical information recording medium.
- a dichroic coat that does not allow the light beam of the wavelength ⁇ 3 to pass through when divided into an outer region far from the optical axis, to record information on the third optical information recording medium.
- the wavelength ⁇ The dichroic coat that does not allow the light flux of 3 to pass through is applied to the outer area, so that the effective diameter corresponding to the numerical aperture NAC of the objective optical element and the effective diameter corresponding to the numerical aperture NAC of the coupling lens overlap.
- the effective diameter corresponding to the numerical aperture NAC of the objective optical element and the effective diameter corresponding to the numerical aperture NAC of the coupling lens overlap.
- Item 45 is an optical pickup device according to any one of Items 37 to 44, wherein the light beam of the wavelength I1 passes through the coupling lens. Incident on the optical element.
- Item 46 is the optical pickup device according to any one of Items 23 to 44, wherein the optical pickup device according to any one of Items 23 to 44 is on the optical path of the light flux of the wavelength; If the aperture limiting element for the light beam of the wavelength ⁇ 3 is arranged, it is possible to appropriately record and / or reproduce information on the third optical information recording medium.
- Item 47 is the optical pickup device according to Item 46, wherein the aperture limiting element is preferably a dichroic filter.
- Item 48 The optical pickup device according to Item 46, wherein the aperture limiting element is preferably a dichroic prism.
- the optical pickup device described in Item 49 is compatible with the optical pickup device described in Item 46.
- the aperture limiting element is a force-pulling lens.
- Item 50 is the optical pickup device according to Item 46, wherein the aperture limiting element is preferably a retardation plate.
- Item 51 is the optical pickup device according to any one of Items 23 to 44 and 46 to 50, wherein at least one optical surface of the optical element includes the first optical information.
- the first light source, the second light source, and the third light source respectively.
- Wavelengths respectively emitted from the first light source and the second light source a force S for passing the light beams of 1 and 2; and a dichroic light that does not pass the light beam of the wavelength ⁇ 3 emitted from the third light source.
- a second area on which a topical coat has been applied a second area on which a topical coat has been applied.
- Item 52 is the optical pickup device according to Item 51, wherein no diffractive structure is provided on the optical surface on which the dichroic coat is applied.
- the operation and effect of the present optical pickup device are the same as those of the optical pickup device described in [16].
- Item 53 The optical pickup device according to any one of Items 23 to 44 and 46 to 52, wherein at least one optical surface of the condensing optical system is the first optical surface.
- the first light source, the second light source, and the third light source respectively.
- Illuminated wavelength; I 1, ⁇ 2 and; 3 The first light source and the second light source respectively irradiate the first area to be passed and the first optical information recording medium and the second optical information recording medium to perform recording and Z or reproduction respectively.
- Item 54 The optical pickup device according to any one of Items 23 to 44 and 46 to 53, wherein at least one optical surface of the optical element includes the first optical information.
- the second optical information recording medium, and the third optical information recording medium respectively, the first light source, the second light source, and the third light source respectively.
- the light fluxes of wavelength ⁇ 3 radiated from the third light source A second area that does not converge on the information recording surface even when The first region is provided with a first diffraction structure, and the second region is provided with a second diffraction structure.
- the order of the diffracted light having the highest diffraction efficiency is ⁇ 1 ⁇ , the order of the diffracted light having the highest diffraction efficiency among the diffracted lights of the wavelength generated by the first diffraction structure; among diffracted light with wavelength lambda 1 generated by the diffractive structure, the order number of diffracted light having the maximum diffraction efficiency eta 2 Alpha, the second resulting Ru wavelength by the diffractive structure; among the L 2 diffracted light, maximum diffraction
- the order of the diffracted light having efficiency is n 2 D, n 1 A: n 1 D ⁇ n 2A: n 2D (9).
- the operation and effect of this optical pickup device are the same as those of the optical pickup device described in Item 17.
- Item 55 is the optical pickup device according to any one of Items 23 to 44 and 46 to 53, wherein at least one optical surface of the optical element includes the first optical information recording medium, (2) wavelengths respectively irradiated from the first light source, the second light source, and the third light source to perform recording and / or reproduction on the optical information recording medium and the third optical information recording medium, respectively; I 1, ⁇ 2 and I; a first area through which the luminous flux passes, and the first optical information recording medium and the second optical information recording medium for performing recording and / or reproduction on the first optical information recording medium, respectively.
- the wavelengths respectively emitted from the first light source and the second light source; the forces for passing the light fluxes of 1 and ⁇ 2 and condensing them on the information recording surface The light flux of the wavelength ⁇ 3 emitted from the third light source And a second area that is not focused on the information recording surface even when The first region is provided with a first diffraction structure, and the second region is provided with a second diffraction structure.
- the order of the diffracted light having the maximum diffraction efficiency is ⁇ 1 ⁇ , and the wavelength generated by the first diffraction structure; out of the twelve diffracted lights, the order of the diffracted light having the maximum diffraction efficiency is n ID;
- the order of the diffracted light having the highest diffraction efficiency is defined as n 2 A, and the wavelength generated by the second diffractive structure;
- n lA: n lD n 2A: n 2D (10), where n 2 A is an odd number.
- the operation and effect of this optical pickup device are the same as those of the optical pickup device described in Item 18.
- the operational effects of the present optical pickup device are the same as those of the optical pickup device described in Item 19.
- the operation and effect of this optical pickup device are the same as those of the optical pickup device described in Item 20.
- Item 58 is the optical pickup device according to any one of Items 55 to 57, wherein the maximum diffraction efficiency of the diffracted light having the wavelength of 3 generated by the second diffraction structure; 60% or less.
- the operation and effect of this optical pickup device are the same as those of the optical pickup device described in Item 21.
- Item 59 is the optical pickup device according to any one of Items 55 to 58, wherein the optical pickup device performs color correction on the light beam of the wavelength ⁇ 1.
- the function and effect of this optical pickup device are the same as those of the optical pickup device described in Item 22.
- Item 60 is the optical pickup device according to any one of Items 33 to 59, wherein the third light source and the photodetector are united if the third light source is a holo laser. Therefore, the optical pickup device can be made more compact.
- the optical pickup device is the optical pickup device according to item 33, further comprising a second element for performing chromatic aberration correction on the light beam having the wavelength I1 on the optical path of the light beam having the wavelength ⁇ 1.
- a second element for performing chromatic aberration correction on the light beam having the wavelength I1 on the optical path of the light beam having the wavelength ⁇ 1.
- Item 62 The optical pickup device according to Item 61, wherein the optical pickup device according to Item 61 performs chromatic aberration correction on the light path of the wavelength; I2 on the optical path of the light of the wavelength I2. If the second chromatic aberration correction element for arranging the second optical information recording medium is disposed, it is possible to appropriately record and Z or reproduce information on the second optical information recording medium.
- Item 63 The optical pickup device according to Item 33, wherein the optical pickup device according to Item 33 performs chromatic aberration correction on the light beam of the wavelength ⁇ 1 on an optical path through which only the light beam of the wavelength ⁇ 1 passes. And a second chromatic aberration correcting element for performing chromatic aberration correction on the light beam of the wavelength ⁇ 2 is disposed on an optical path through which only the light beam of the wavelength; I2 passes.
- information can be recorded and / or reproduced appropriately on the first and second optical information recording media.
- the optical pickup device is the optical pickup device according to Item 33, wherein on the optical path through which the light flux of the wavelength; L1 and the light flux of the wavelength; I2 pass in common.
- a first chromatic aberration correcting element for correcting chromatic aberration with respect to the light beam having the wavelength ⁇ 1 is disposed, and for performing chromatic aberration correction on the light beam having the wavelength ⁇ 2 on an optical path through which only the light beam having the wavelength L2 passes. If the second chromatic aberration correcting element is arranged, it is possible to appropriately record and / or reproduce information on the first and second optical information recording media.
- the optical pickup device is the optical pickup device according to any one of items 21 or 61 through 64, wherein the light beam of the wavelength; I1 and the light beam of the wavelength 2 are common. If the collimator is arranged on the optical path through which the light passes, the information can be appropriately recorded and / or reproduced with respect to the first and second optical information recording media.
- Item 66 is the optical pickup device according to Item 65, wherein on the optical path through which the light beam of wavelength 1 passes, on the light source side of the collimator, the wavelength; If the first beam shaper for shaping the luminous flux is arranged, it is possible to appropriately record, read, or reproduce information on the first optical information recording medium.
- the optical pickup device described in Item 66 is compatible with the optical pickup device described in Item 66.
- the l-th beam shaper can appropriately record and / or reproduce information on the first optical information recording medium, and configure an optical pickup device. Can be further simplified.
- Item 68 is the optical pickup device according to Item 65, wherein on the optical path through which the light flux of the wavelength; L2 passes, on the light source side of the collimator, the optical pickup device of the wavelength 2 If the second beam shaper for shaping the light beam is arranged, it is possible to appropriately record and Z or reproduce information on the second optical information recording medium.
- Item 69 is the optical pickup device according to Item 68, wherein the second beam shaper corrects the chromatic aberration of the light flux of the wavelength; Information can be appropriately recorded and Z or reproduced on the optical information recording medium, and the configuration of the optical pickup device can be further simplified.
- Item 70 is the optical pickup device according to Item 65, wherein the light beam of the wavelength; I1 and the second light beam pass through a common optical path. If a beam shaper for shaping the light beam of the wavelength 1 or shaping the light beam of the wavelength 2 is disposed closer to the light source than the collimator, the beam shaper for the first and second optical information recording media is provided. Information can be recorded and / or reproduced appropriately.
- Item 71 is the optical pickup device according to any one of Items 65 to 70, in which the collimator can be produced at low cost if the glass material is plastic.
- Item 72 The optical pickup device according to Item 65, wherein in the optical pickup device according to Item 65, on the optical path through which the light flux of the wavelength; 1 and the light flux of the wavelength ⁇ 2 pass in common,
- a beam shaping prism for shaping the light beam of the wavelength; I 1 or shaping the light beam of the wavelength 2 is disposed between the collimator and the condensing optical system, Information can be appropriately recorded and / or reproduced on the first and second optical information recording media.
- Item 74 is the optical pickup device according to any one of Items 33 and 61 to 63, wherein the first collimator is disposed on an optical path through which only the light beam of the wavelength 1 passes.
- the second collimator is arranged on the optical path through which only the light flux of I2 passes, information can be recorded and / or reproduced appropriately on the first and second optical information recording media. Can be performed.
- Item 75 is the optical pickup device according to Item 74, wherein the glass material of at least one of the first collimator and the second collimator is plastic. Can be produced at low cost.
- Item 76 The optical pickup device according to Item 75, wherein the at least one of the collimators made of plastic as a glass material is a chromatic aberration correction element, and the first and Z or the optical pickup device according to Item 75. Information can be appropriately recorded and / or reproduced on the second optical information recording medium.
- Item 77 is the optical pickup device according to Item 74, wherein on the optical path through which the light beam of the wavelength 1 passes, on the light source side of the first collimator, the light pickup device of the wavelength 1 If the first beam shaper for shaping the light beam is arranged, it is possible to appropriately record, read, or reproduce information on the first optical information recording medium.
- Item 78 is the optical pickup device according to Item 77, wherein the first beam shaper is the first chromatic aberration correction element, The information can be appropriately recorded and / or reproduced on the information recording medium, and the configuration of the optical pickup device can be further simplified.
- Item 79 is the optical pickup device according to Item 78, wherein on the optical path through which the light beam of the wavelength ⁇ 2 passes, on the light source side of the collimator, the wavelength: I 2 If the second beam shaper for shaping the light beam is disposed, information can be recorded and read or reproduced on the second optical information recording medium appropriately.
- the optical pickup device according to item 80 is the optical pickup device according to item 79, wherein the second beam shaper is the second chromatic aberration correction element, and the optical pickup device according to item 79, Information can be appropriately recorded and read or reproduced, and the configuration of the optical pickup device can be further simplified.
- Item 81 The optical pickup device according to Item 74, wherein the optical pickup device according to Item 74 includes an optical path between the first collimator and the condensing optical system on the optical path of the light of the wavelength; I1. If a first beam shaping prism for shaping the light beam having the wavelength ⁇ 1 is provided, information can be appropriately recorded and / or reproduced on the first optical information recording medium.
- the optical pickup device according to Item 82 is the optical pickup device according to Item 81, wherein an optical path between the second collimator and the condensing optical system is provided on an optical path of the light having the wavelength 2. If a second beam shaping prism for shaping the light beam having the wavelength of I2 is provided, information can be appropriately recorded and read or reproduced on the second optical information recording medium.
- Item 83 is the optical pickup device according to any one of Items 37 to 82, wherein the optical element is preferably an objective lens (that is, an objective optical element).
- “Chromatic aberration correction” as used in this specification refers to the suppression of fluctuations in the focal spot position (position at which the wavefront aberration of the focal spot is minimized) in the optical axis direction due to the objective optical element when the wavelength changes.
- the wavefront aberration after the wavelength change at the condensed spot position before the wavelength change is the information recording and Z or reproduction on the optical information recording medium. It means that it can be suppressed to the extent possible.
- “to make the spherical aberration under” means that, as shown in FIG. 1, the spherical aberration having the origin at the paraxial image point position and the optical axis closer to the object point than the paraxial image point. The intersection is defined as “under”. Note that the case where the optical axis intersects with the optical axis on the image point side from the paraxial image point is referred to as “over”.
- the term “diffraction structure” refers to a portion provided with a relief on the surface of an optical element to condense or diverge a light beam by diffraction.
- the shape of the relief is formed on the surface of the optical element as a substantially concentric annular zone centered on the optical axis.Each annular zone looks like a sawtooth when its cross section is viewed on a plane including the optical axis. Although the shape is known, it includes such a shape, and such a shape is particularly called a “diffraction ring zone”.
- the objective optical element is, in a narrow sense, a light condensing element that is disposed at the position closest to the optical information recording medium when the optical information recording medium is loaded in the optical pickup device.
- a lens that has an effect eg, an objective lens
- the numerical aperture NA of the optical element on the optical information recording medium side refers to the numerical aperture NA of the surface of the optical element located closest to the optical information recording medium.
- the required numerical aperture NA is the numerical aperture defined by the standard of each optical information recording medium, or each optical information recording medium. It shall indicate the numerical aperture of the objective lens with diffraction-limited performance that can obtain the spot diameter necessary for recording or reproducing information according to the wavelength of the light source used for the body.
- the first optical information recording medium refers to, for example, a high-density DVD-based optical disc
- the second optical information recording medium refers to a DVD-ROM, DV DVideo other than DVD-ROM used for reproduction only.
- the third optical information recording medium refers to a CD-type optical disk such as a CD-R or a CD-RW.
- Fig. 2 shows the recording and playback of information on all of high-density DV D (also called first optical disc), conventional DVD (also called second optical disc) and CD (also called third optical disc).
- 1 is a schematic configuration diagram of an optical information recording / reproducing device or an optical pickup device according to a first embodiment, which can perform the following.
- the first semiconductor laser 111 and the second semiconductor laser 112 are arranged adjacently on the same substrate to form a unit light source such as a so-called two-laser one package. It corresponds to the optical pickup device described in Sections 11 and 33.
- the protection layer 2 1 (thickness t
- the light flux modulated and reflected by the information pits on the information recording surface 22 again passes through the objective lens 16 and the aperture 17 and passes through the second beam splitter 1 16 and the collimator 1 15 again.
- the two-dimensional actuator moves the objective lens 16 so that the light beam from the first semiconductor laser 111 forms an image on the recording surface 22 of the first optical disk 20.
- the objective lens 16 is moved so that the light beam from the semiconductor laser 111 is focused on a predetermined track.
- the light flux modulated and reflected by the information pits on the information recording surface 22 passes through the objective lens 16 and the aperture 17 again and passes through the second beam splitter 1 16 and the collimator 1 15.
- the light passes through the first beam splitter 1 14, is reflected there, is given astigmatism by the cylindrical lens 1 17, and passes through the concave lens 1 18.
- the optical detector 1 1 9 above by using its output signal, the read signal of the information to the second optical disk 2 0 is the information recording is obtained.
- a change in light amount due to a change in spot shape and a change in position on the photodetector 119 is detected to perform focus detection and track detection.
- a two-dimensional actuator (not shown) forms an image of the light beam from the second semiconductor laser 112 onto the recording surface 22 of the second optical disk 20 so that the objective lens 1 While moving 6, the objective lens 16 is moved so that the light beam from the semiconductor laser 112 is focused on a predetermined track.
- the light beam modulated and reflected by the information pits on the information recording surface 22 again passes through the objective lens 16 and the aperture 17 and is incident on the second beam splitter 116, where it is reflected and collimated. After passing through 1 2 5, it enters the third beam splitter 1 2 4, is further reflected, is astigmatized by the cylindrical lens 1 2 7, and is incident on the photodetector 1 2 9 through the concave lens 1 2 8. And the read signal of the information recorded on the third optical disk 20 is obtained using the output signal.
- the two-dimensional actuator (not shown) forms an image of the light beam from the third semiconductor laser 121 onto the recording surface 22 of the third optical disk 20 so that the objective lens 16 can form an image. Is moved, and the objective lens 16 is moved so that the light beam from the semiconductor laser 121 is focused on a predetermined track.
- the first light source and the second light source are arranged on the same substrate.
- the present invention is not limited thereto, and the second light source and the third light source may be arranged on the same substrate, and the first light source, the second light source, and the third light source may be arranged not on the same substrate but at different positions. It is good.
- FIG. 3 shows recording and playback of information on all of high-density DVD (also called first optical disk), conventional DVD (also called second optical disk) and CD (also called third optical disk).
- FIG. 4 is a schematic configuration diagram of an optical information recording / reproducing device or an optical pickup device according to a second embodiment.
- BS 1 a parallel light beam by a plastic collimator PLC L
- OBL an objective lens
- the light beam modulated and reflected by the information pits on the information recording surface RP passes through the objective lens OBL again, passes through the second beam splitter BS2, the collimator PLCL, and the first beam splitter BS1, and After passing through the wave plate HF, the light is incident on the photodetector AS for the first light source, and a read signal of information recorded on the first optical disk DSK is obtained using the output signal.
- a two-dimensional actuator moves the objective lens OBL so that the light beam from the first semiconductor laser A is focused on the recording surface RP of the first optical disk DSK, and the semiconductor laser AL The objective lens OBL is moved so that the light beam from the lens is focused on a predetermined track.
- the light beam emitted from the first beam splitter BS 1 is reflected by the first beam splitter BS 1, converted into a parallel light beam by the plastic collimator PLCL, and further passed through the second beam splitter BS 2 to be condensed.
- the light flux modulated and reflected by the information pits on the information recording surface RP passes through the objective lens OBL again, passes through the second beam splitter BS2 and the collimator PLCL, and is reflected by the first beam splitter BS1. Then, the light is incident on a photodetector (not shown) in the second semiconductor laser DHL, and a read signal of information recorded on the second optical disk DSK is obtained by using the output signal.
- a two-dimensional actuator (not shown) moves the objective lens OBL so that the light beam of the second semiconductor laser DHL is focused on the recording surface RP of the second optical disk DSK. Then, the objective lens OBL is moved so that the light beam from the semiconductor laser DHL is focused on a predetermined track.
- the light beam modulated and reflected by the information pits on the information recording surface RP passes through the objective lens OBL again, enters the second beam splitter BS2, is reflected there, and is condensed by the coupling lens CPL. Then, it is incident on a photodetector (not shown) in the third semiconductor laser CHL, and a read signal of information recorded on the third optical disk DSK is obtained using the output signal.
- the two-dimensional actuator (not shown) moves the objective lens OBL so that the light beam from the third semiconductor laser CHL is focused on the recording surface RP of the third optical disk DSK, and the semiconductor laser The objective lens OBL is moved so that the light beam from the CHL is focused on a predetermined track.
- a circular non-film portion corresponding to a numerical aperture capable of appropriately recording and / or reproducing information (a film centered on the optical axis is not formed) on the information recording surface RP of the third optical disc DSK.
- the information recording surface RP of the third optical disc DSK is appropriately provided between the second beam splitter BS2 and the objective lens OBL.
- a dichroic filter provided with a dichroic coat having a circular non-film portion corresponding to a numerical aperture capable of performing recording and Z or reproduction of the data may be provided as an aperture limiting element.
- the dichroic coat functions to block only the light beam of wavelength ⁇ 3 from the third semiconductor laser CHL. (See Section 47).
- an aperture limiting element may be provided by providing a dichroic prism formed with a dike aperture coat having a circular non-film portion corresponding to the numerical aperture at which reproduction can be performed.
- the dichroic coat functions to block only the light beam of the wavelength; L3 from the third semiconductor laser CHL (see Section 51).
- the region with the dichroic coat functions as the second region because it blocks only the light beam of wavelength ⁇ 3 from the third semiconductor laser C, and the circular non-film portion functions as the first region. (See Section 50). In such a case, no diffraction structure is provided in the area where the dichroic coat is located (see Section 51).
- a diffractive structure is provided in the circular non-film portion of the objective lens OBL to correct the chromatic aberration of the light beam from the first semiconductor laser AL or the light beam from the second semiconductor laser DHL. See sections 37 and 38). That is, the objective lens OBL constitutes the first chromatic aberration correction element or the second chromatic aberration correction element.
- a diffraction structure having a similar chromatic aberration function may be provided in the corresponding region of the collimator PLCL.
- the photodetector AS instead of using the second semiconductor laser DHL as a holo laser, the photodetector AS not only reflects the reflected light of the luminous flux of the wavelength ⁇ 1 from the first semiconductor laser AL but also generates the second light.
- the reflected light of the light beam of wavelength 2 from the semiconductor laser DHL may also be detected.
- beam shaping is not performed, but as a modified example, a beam sipper is disposed closer to the light source than the collimator PLCL through which the light beam of wavelength 1 and the light beam of wavelength 2 pass in common.
- the beam of wavelength; I1 or the beam of wavelength 2 can be shaped (see Sections 64 and 66).
- the collimator PLCL may have a beam shaping function.
- the beam shaper refers to an optical element having a function of, for example, injecting a light beam having an elliptical cross-sectional shape, shaping the light beam into a circular cross-sectional shape, and emitting the light.
- the optical surface of the objective lens OBL is used to record and / or reproduce data on / from the first optical disk, the second optical disk, and the third optical disk, respectively.
- the first region has a first diffraction structure, and the second region has a second diffraction structure.
- the order of the diffracted light having the maximum diffraction efficiency among the diffracted lights of 1 is defined as n 1 A
- the diffracted light having the maximum diffraction efficiency among the diffracted lights of the wavelength ⁇ 2 generated by the first diffraction structure is defined as n 1 A.
- Degree Is n ID the order of the diffracted light having the maximum diffraction efficiency among the diffracted lights of wavelength 2 generated by the second diffraction structure is n 2 A
- the diffraction light of wavelength ⁇ 2 generated by the second diffraction structure is When the order of the diffracted light having the maximum diffraction efficiency is ⁇ 2 D,
- n 1 D n 2 A: n 2D (10), where n 2 A is odd (see Section 18).
- the maximum diffraction efficiency of the diffracted light of the wavelength L3 generated by the second diffraction structure is 60 ° / 0 or less (see Section 21).
- n2A is not limited to an odd number (see Section 17).
- FIG. 4 shows the recording and playback of information on all high-density DVDs (also called first optical discs), conventional DVDs (also called second optical discs), and CDs (also called third optical discs).
- FIG. 9 is a schematic configuration diagram of an optical information recording / reproducing device or an optical pickup device according to a third embodiment. It should be noted that the present embodiment is different from the embodiment of FIG. 3 in that the distance between the second semiconductor laser DHL and the first beam splitter BS1 (on the optical path through which only the light beam of wavelength L2 passes). The only difference is that the wavelength from the second semiconductor laser DHL; the chromatic aberration correcting optical element DSE having a diffractive structure that corrects the chromatic aberration for the light flux of I 2 is arranged.
- a diffraction structure is provided on the objective lens OBL or the collimator P LCL on the optical path through which the light beam of the wavelength ⁇ 1 and the light beam of the wavelength ⁇ 2 pass in common, and the light beam from the first semiconductor laser ⁇ ⁇ ⁇ ⁇ is provided.
- Chromatic aberration can be corrected (see Sections 59 and 61).
- the chromatic aberration of the light beam from the second semiconductor laser DHL is corrected by the diffractive structure of the objective lens OBL, and the collimator PLC
- the chromatic aberration of the light beam from the first semiconductor laser A can be corrected by the L diffraction structure.
- FIG. 5 shows the recording and playback of information on all of high-density DVDs (also called first optical discs), conventional DVDs (also called second optical discs), and CDs (also called third optical discs).
- FIG. 14 is a schematic configuration diagram of an optical information recording / reproducing device or an optical pickup device according to a fourth embodiment.
- the light beam modulated and reflected by the information pits on the information recording surface RP passes through the objective lens OBL again, passes through the second beam splitter BS2, is reflected by the prism P, passes through the 1Z4 wave plate HF, and Then, the light is incident on the photodetector ADS, and a read signal of information recorded on the first optical disk DSK is obtained using the output signal.
- the two-dimensional actuator (not shown) moves the objective lens OBL so that the light beam from the first semiconductor laser AL forms an image on the recording surface RP of the first optical disc DSK, and the semiconductor laser The objective lens OBL is moved so that the light beam from the AL is focused on a predetermined track.
- the beam shaping prism BSP After being converted, it is further shaped when passing through the beam shaping prism BSP, passes through the second beam splitter BS2, and is protected by the objective lens OBL as a condensing optical element with the protective layer TL of the second optical disk DSK.
- Thiickness t 2 0.5 to 0.7 mm, preferably 0.6 mm
- the light flux modulated and reflected by the information pits on the information recording surface RP passes through the objective lens OBL again, passes through the second beam splitter BS2, is reflected by the prism P, and passes through the quarter-wave plate HF.
- the light passes through the photodetector ADS, and the read signal of the information recorded on the second optical disk DSK is obtained using the output signal.
- the two-dimensional actuator (not shown) moves the objective lens OBL so that the light beam from the second semiconductor laser DL is focused on the recording surface RP of the second optical disc DSK, and the semiconductor laser is moved.
- the objective lens OBL is moved so that the light flux from the first DL is focused on a predetermined track.
- the light is condensed, incident on a photodetector (not shown) in the third semiconductor laser CHL, and a read signal of information recorded on the third optical disk DSK is obtained using the output signal.
- the two-dimensional actuator (not shown) moves the objective lens OBL so that the light beam from the third semiconductor laser CHL is focused on the recording surface RP of the third optical disk DSK, The objective lens OBL is moved so that the light beam from the laser CHL is focused on a predetermined track.
- a circular non-film portion (a film centered on the optical axis) corresponding to a numerical aperture capable of appropriately recording and Z or reproducing information is formed on the information recording surface RP of the third optical disc DSK1.
- a light-shielding film having a non-circular area to the optical surface of the coupling lens CPL, the light flux of the wavelength L3 is transmitted through only the circular non-film portion to allow the coupling lens CPL to pass. It can be used as an aperture limiting element (see Sections 48 and 51).
- the information recording surface RP of the third optical disc DSK may be appropriately provided between the second beam splitter BS2 and the objective lens OBL.
- a dichroic filter provided with a dichroic coat having a circular non-film portion corresponding to a numerical aperture capable of recording and Z or reproducing information may be provided as an aperture limiting element.
- the dichroic coat functions to block only the light beam of wavelength 3 from the third semiconductor laser CHL. (See Section 49).
- the dichroic prism instead of providing a light-shielding film on the coupling lens CPL, information can be appropriately recorded and Z or reproduced on the information recording surface RP of the third optical disc DSK, for example, in the optical path of wavelength: 3. It is also possible to provide a dichroic prism formed with a dichroic coat having a circular non-film portion corresponding to the numerical aperture capable of performing the above operation, and use the dichroic prism as an aperture limiting element. In this case, the dichroic coat functions so as to block only the light beam of wavelength ⁇ 3 from the third semiconductor laser CHL from passing through (see Section 50).
- the coupling lens CPL instead of providing a light-shielding film on the coupling lens CPL, for example, information recording and Z or reproduction can be appropriately performed on the information recording surface RP of the third optical disc DSK on the optical surface of the objective lens OBL.
- a dichroic coat having a circular non-film portion corresponding to the numerical aperture capable of performing the above-described process may be formed.
- the region with the dichroic coat functions as the second region because it blocks only the luminous flux of wavelength 3 from the third semiconductor laser CHL, and the circular non-film portion functions as the first region. See 5 1). In such a case, no diffraction structure is provided in the area where the dichroic coat is located (see Section 52).
- a diffractive structure is provided in the circular non-film portion of the objective lens OBL to correct chromatic aberration of the light beam from the first semiconductor laser AL or the light beam from the second semiconductor laser D. See 6 4). That is, the objective lens OBL constitutes the first chromatic aberration correction element or the second chromatic aberration correction element.
- a diffraction structure having a similar chromatic aberration function may be provided in the corresponding region of the collimator GMCL.
- the collimator GMCL and the objective lens OB are arranged so that the beam shaping prism BSP passes through the optical path through which the light beam of wavelength; I1 and the light beam of wavelength; By arranging it between L and L, beam shaping of the light beam from the first semiconductor laser AL and the light beam from the second semiconductor laser DL is performed (see Section 66).
- FIG. 6 shows the recording / reproducing of information on all of high-density DVD (also called first optical disc), conventional DVD (also called second optical disc) and CD (also called third optical disc).
- FIG. 15 is a schematic configuration diagram of an optical information recording / reproducing device or an optical pickup device according to a fifth embodiment.
- the light flux modulated and reflected by the information pits on the information recording surface RP passes through the objective lens OBL again, passes through the second beam splitter BS2 and the collimator PLCL, and is reflected by the third beam splitter BS3. Then, the light passes through the quarter-wave plate HF, is incident on the photodetector ADS, and a read signal of information recorded on the first optical disk DSK is obtained by using the output signal.
- a two-dimensional actuator moves the objective lens OBL so that the light beam from the first semiconductor laser AL is focused on the recording surface RP of the first optical disk DSK, The objective lens OBL is moved so that the light beam from the laser A is focused on a predetermined track.
- the light flux modulated and reflected by the information pits on the information recording surface RP passes through the objective lens OBL again, passes through the second beam splitter BS2 and the collimator PLCL, and is reflected by the third beam splitter BS3. Then, the light passes through the 1Z4 wavelength plate HF, is incident on the photodetector ADS, and the read signal of the information recorded on the first optical disk DSK is obtained using the output signal.
- a two-dimensional actuator moves the objective lens OBL so that the light beam from the second semiconductor laser DHL is focused on the recording surface RP of the second optical disk DSK, and The objective lens OBL is moved so that the light beam from the semiconductor laser DHL is focused on a predetermined track.
- the luminous flux emitted from the third semiconductor laser CHL (wavelength 3-700 nm to 800 nm), which is the third light source and the holo laser, passes through the coupling lens CPL, and passes through the second beam splitter BS 2.
- the light beam modulated and reflected by the information pits on the information recording surface RP passes through the objective lens OBL again, enters the second beam splitter BS2, is reflected there, and is collected by the coupling lens CPL.
- the light is incident on a photodetector (not shown) in the third semiconductor laser CHL, and a read signal of information recorded on the third optical disk DSK is obtained using the output signal.
- the two-dimensional actuator (not shown) moves the objective lens OBL so that the light beam from the third semiconductor laser CH is focused on the recording surface RP of the third optical disk DSK,
- the objective lens OBL is moved so that the light beam from the laser CHL is focused on a predetermined track.
- a circular non-film portion (a film centered on the optical axis is not formed on the information recording surface RP of the third optical disc DSK corresponding to a numerical aperture capable of appropriately recording and Z or reproducing information.
- the information recording surface RP of the third optical disc DSK may be provided instead of providing a light-shielding film on the coupling lens CPL, for example, between the second beam splitter BS2 and the objective lens OBL.
- a dichroic filter having a dichroic coat having a circular non-film portion corresponding to a numerical aperture capable of appropriately recording and Z or reproducing information may be provided as an aperture limiting element. In this case, the dichroic coat functions to block only the light beam of wavelength ⁇ 3 from the third semiconductor laser CHL. You.
- An aperture limiting element may be provided by providing a dichroic prism formed with a dike aperture coat having a circular non-film portion corresponding to the numerical aperture capable of performing the above operation.
- the dichroic coat functions to block the passage of only the light beam of wavelength: 3 from the third semiconductor laser CHL.
- a light-shielding film on the coupling lens CPL for example, information can be appropriately recorded and / or reproduced on the information recording surface RP of the third optical disc DSK on the optical surface of the objective lens OBL.
- a dichroic coat having a circular non-film portion corresponding to the numerical aperture capable of performing the above-described process may be formed.
- the region with the dichroic coat functions as the second region because it blocks only the light beam of wavelength ⁇ 3 from the third semiconductor laser C H, and the circular non-film portion functions as the first region. In such a case, no diffraction structure is provided in the area where the dichroic coat is located.
- a diffractive structure is provided in the circular non-film portion of the objective lens OBL to correct chromatic aberration with respect to the light beam from the first semiconductor laser AL or the light beam from the second semiconductor laser DHL. That is, the objective lens OBL constitutes the first chromatic aberration correction element or the second chromatic aberration correction element.
- a diffractive structure having a similar chromatic aberration function is provided in the corresponding collimator PLCL or beam sipper BSE area. You may.
- the beam shaper BSE passes the light from the collimator PLCL on the optical path through which the light beam of wavelength; 1 and the light beam of wavelength ⁇ 2 pass in common.
- the beam from the first semiconductor laser A and the beam from the second semiconductor laser DL are shaped.
- FIG. 7 shows the recording and playback of information on all high-density DVDs (also called first optical discs), conventional DVDs (also called second optical discs), and CDs (also called third optical discs).
- FIG. 15 is a schematic configuration diagram of an optical information recording / reproducing device or an optical pickup device according to a sixth embodiment. Note that the present embodiment differs from the embodiment of FIG. 6 only in that the beam shaper BSE is arranged between the second semiconductor laser DHL and the first beam splitter BS1. The other points are the same as those of the embodiment (including the modified example) in FIG. In the present embodiment, the beam shaping is performed only for the light beam of wavelength; I1.
- FIG. 15 is a schematic configuration diagram of an optical information recording / reproducing device or an optical pickup device according to a seventh embodiment.
- a common collimator is eliminated from the embodiment shown in FIG. 3, and a dedicated light beam from the first light source is provided between the first semiconductor laser AL and the first beam splitter BS1.
- the first plastic collimator APLCL is placed between the second semiconductor laser DHL and the first beam splitter BS1, and the second plastic collimator DP LCL dedicated to the luminous flux from the second light source is placed between the second semiconductor laser DHL and the first beam splitter BS1.
- the first collimator APLCL through which only the light beam of wavelength; I1 passes can be provided with a diffraction structure to correct chromatic aberration for the light beam of wavelength ⁇ 1, and only the light beam of wavelength; L2 passes.
- Diffraction structure on 2nd collimator DPLCL The chromatic aberration can be corrected for the luminous flux of wavelength 2 (see Sections 62, 63, and 64).
- FIGS. 9 to 13 Providing such a diffractive structure for correcting chromatic aberration in a collimator dedicated to a light beam having a wavelength of ⁇ ⁇ ⁇ and a collimator dedicated to a light beam having a wavelength of I2 is described in FIGS. 9 to 13 described later. It can be applied to the embodiment. The other points are the same as in the embodiment (including the modified example) in FIG. 3, and the description is omitted.
- Fig. 9 shows the recording and playback of information on all of high-density DVD (also called first optical disk), conventional DVD (also called second optical disk), and CD (also called third optical disk).
- FIG. 27 is a schematic configuration diagram of an optical information recording / reproducing device or an optical pickup device according to an eighth embodiment that can be performed.
- a plastic collimator DPLCL dedicated to the light beam from the second light source is provided with a diffraction structure so that chromatic aberration can be corrected for the light beam having the wavelength of 2.
- the difference was in the way they were done.
- the other points are the same as those of the embodiment (including the modified example) in FIG. 3 or FIG. 8, and the description is omitted.
- FIG. 10 shows the recording / recording of information on all of high-density DVD (also called first optical disk), conventional DVD (also called second optical disk) and CD (also called third optical disk).
- FIG. 27 is a schematic configuration diagram of an optical information recording / reproducing apparatus or an optical pickup apparatus according to a ninth embodiment that can perform reproduction.
- the beam is shaped into a parallel light beam by the first beam shaping prism BSP, and then beam shaped by the first beam shaping prism BSP (see section 72).
- the light beam modulated and reflected by the information pits on the information recording surface RP passes through the objective lens OBL again, passes through the second beam splitter BS2, is reflected by the first beam splitter BS1, and The signal passes through the / 4 wavelength plate HF, enters the photodetector AS, and uses the output signal to obtain a signal for reading information recorded on the first optical disk DSK.
- a two-dimensional actuator (not shown) moves the objective lens OBL so that the light beam from the first semiconductor laser AL is focused on the recording surface RP of the first optical disc DSK, and the two-dimensional actuator is moved from the semiconductor laser AL.
- the objective lens OBL is moved so that the luminous flux is focused on a predetermined track.
- the light is reflected by P, passes through the first beam splitter BS 1 and the second beam splitter BS 2, and enters the objective lens OBL as a condensing optical element, from which the second optical disc D SK
- the light beam modulated and reflected by the information pits on the information recording surface RP passes through the objective lens OBL again, passes through the second beam splitter BS 2 and the first beam splitter BS 1, and The light is reflected by P, passes through the second collimator D PLC L, is incident on the photodetector (not shown) in the second semiconductor laser DHL, and the output signal is By using this, a read signal of information recorded on the second optical disk DSK is obtained. It also detects changes in the amount of light due to changes in the shape and position of the spot on the photodetector, and performs focus detection and track detection.
- a two-dimensional actuator moves the objective lens OBL so that the light beam from the second semiconductor laser DHL is focused on the recording surface RP of the second optical disk DSK,
- the objective lens OBL is moved so that the light beam from the semiconductor laser DHL is focused on a predetermined track.
- the light flux modulated and reflected by the information pits on the information recording surface RP passes through the objective lens OBL again, is incident on the second beam splitter BS2, is reflected there, and is reflected by the coupling lens CP L. Then, the light is focused on a photodetector (not shown) in the third semiconductor laser CHL, and a read signal of information recorded on the third optical disk DSK is obtained by using the output signal.
- the two-dimensional actuator moves the objective lens OBL so that the light beam from the third semiconductor laser CHL is focused on the recording surface RP of the third optical disk DSK, Move the objective lens OBL so that the light beam from the laser CHL is focused on a predetermined track.
- a circular non-film portion (circular with no film centered on the optical axis) corresponding to a numerical aperture capable of appropriately recording and / or reproducing information on the information recording surface RP of the third optical disc DSK Area) on the optical surface of the coupling lens CPL to allow the luminous flux of wavelength; I3 to pass through only the circular non-film portion, thereby allowing the coupling lens CPL to pass through the aperture limiting element.
- the information recording surface RP of the third optical disc DSK is appropriately provided between the second beam splitter BS2 and the objective lens OBL.
- a dichroic filter provided with a dichroic coat having a circular non-film portion corresponding to the numerical aperture capable of recording and / or reproducing data Z or reproduction may be provided as an aperture limiting element.
- the dichroic coat functions to block the passage of only the light beam of wavelength ⁇ 3 from the third semiconductor laser CHL.
- a dichroic prism formed with a dike aperture coat having a circular non-film portion corresponding to the numerical aperture at which reproduction can be performed may be provided as an aperture limiting element.
- the dichroic coat functions to block the passage of only the light beam of wavelength 3 from the third semiconductor laser CHL.
- a dichroic coat having a circular non-film portion corresponding to the numerical aperture capable of performing the above-described process may be formed.
- the dichroiter coat A certain region functions as a second region because it blocks only the light beam of wavelength 3 from the third semiconductor laser CH, and the circular non-film portion functions as a first region. In such a case, no diffraction structure is provided in the area where the dichroic coat is located.
- the first collimator APLCL is provided with a diffraction structure
- the chromatic aberration is corrected for the light flux from the first semiconductor laser
- the second collimator DP LCL is provided with a diffraction structure
- the chromatic aberration is corrected for the light beam from the semiconductor laser DHL.
- a diffraction structure having a chromatic aberration correcting function may be provided in the circular non-film portion of the objective lens OBL.
- Fig. 11 shows the recording and playback of information on all high-density DVDs (also called first optical discs), conventional DVDs (also called second optical discs), and CDs (also called third optical discs).
- 1 is a schematic configuration diagram of an optical information recording / reproducing device or an optical pickup device according to a tenth embodiment, which can perform the following.
- a second beam shaping prism BSP 2 dedicated to the light beam from the second light source is provided in place of the prism P in the embodiment shown in FIG.
- beam shaping can be performed on the luminous flux (see Section 82).
- the other points are the same as those of the embodiment (including the modified example) of FIG. 10 and will not be described.
- FIG. 12 shows the recording and playback of information on all of high-density DVDs (also called first optical discs), conventional DVDs (also called second optical discs), and CDs (also called third optical discs).
- FIG. 1 is a schematic configuration diagram of an optical information recording / reproducing device or an optical pickup device according to a first embodiment, which can perform the following.
- the beam is shaped by a 1Z4 wave plate, reflected by the HF, converted into a parallel beam by the first collimator AP LCL made of plastic, and then passed through the first beam splitter BS 1 and the second beam splitter BS 2 to collect light.
- the light beam modulated and reflected by the information pits on the information recording surface RP passes through the reproduction objective lens OBL, and is collected by the second beam splitter BS2, the first beam splitter BS1, and the first collimator APLCL.
- the light is passed through the 1/4 wavelength plate 11 ?, incident on the photodetector AS, and a read signal of information recorded on the first optical disk DSK is obtained using the output signal.
- a two-dimensional actuator (not shown) moves the objective lens OBL so that the light beam from the first semiconductor laser AL is focused on the recording surface RP of the first optical disc DSK, and the two-dimensional actuator is moved from the semiconductor laser AL.
- the objective lens OBL is moved so that the light beam is focused on a predetermined track.
- the light is reflected by the first beam splitter BS1, passes through the second beam splitter BS2, and enters the objective lens OBL as a condensing optical element, from which the protection layer TL (
- the light flux modulated and reflected by the information pits on the information recording surface RP passes through the objective lens OBL again, passes through the second beam splitter BS2, and passes through the first beam splitter BS2.
- the light is reflected by the splitter BS1, passes through the second collimator DP LCL, is incident on a photodetector (not shown) in the second semiconductor laser DHL, and is output to the second optical disc DSK using the output signal.
- a read signal of the recorded information is obtained.
- a two-dimensional actuator moves the objective lens OBL so that the light beam from the second semiconductor laser DHL is focused on the recording surface RP of the second optical disk DSK, The objective lens OBL is moved so that the light beam from the laser DHL is focused on a predetermined track.
- the light flux modulated and reflected by the information pits on the information recording surface RP passes through the objective lens OBL again, enters the second beam splitter BS2, is reflected there, and is reflected by the coupling lens CPL.
- the light is condensed, incident on a photodetector (not shown) in the third semiconductor laser CHL, and a read signal of information recorded on the third optical disk DSK is obtained using the output signal.
- a two-dimensional actuator (not shown) transfers the light beam from the third semiconductor laser CHL to the third optical disk DSK.
- the objective lens OBL is moved so that an image is formed on the recording surface RP, and the objective lens OBL is moved so that the light beam from the semiconductor laser CHL is formed on a predetermined track.
- a circular non-film portion (a film centered on the optical axis is not formed on the information recording surface RP of the third optical disc DSK corresponding to a numerical aperture capable of appropriately recording and Z or reproducing information.
- a light-shielding film having a (circular region) to the optical surface of the power coupling lens CPL, a light beam of wavelength ⁇ 3 is passed through only the circular non-film portion, thereby using the coupling lens CPL as an aperture limiting element. Can be used.
- the information recording surface RP of the third optical disc DSK is appropriately provided between the second beam splitter BS2 and the objective lens OBL.
- a dichroic filter provided with a dichroic coat having a circular non-film portion corresponding to a numerical aperture capable of recording and Z or reproducing information may be provided as an aperture limiting element.
- the dichroic coat functions to block the passage of only the light beam of wavelength: 3 from the third semiconductor laser CHL.
- the coupling lens CPL instead of providing a light-shielding film on the coupling lens CPL, for example, information is appropriately recorded and / or recorded on the information recording surface RP of the third optical disc DSK in the optical path of wavelength; I3. It is also possible to provide an aperture limiting element by providing a dichroic bristle formed with a dike mouthcoat having a circular non-film portion corresponding to the numerical aperture at which reproduction can be performed. In this case, the dichroic coat functions to block the passage of only the light beam of wavelength ⁇ 3 from the third semiconductor laser CHL.
- the information recording surface R of the third optical disk DSK may be provided on the optical surface of the objective lens OBL.
- a dichroic coat having a circular non-film portion corresponding to a numerical aperture capable of appropriately recording and / or reproducing information may be formed on P.
- a certain area of the dichroic coat functions as the second area because it blocks only the light beam of wavelength 3 from the third semiconductor laser CHL, and the circular non-film part functions as the first area. In such a case, no diffraction structure is provided in the area where the dichroic coat is located.
- a diffractive structure is provided in the circular non-film portion of the objective lens OBL through which the light beam of wavelength; I1 and the light beam of wavelength ⁇ 2 pass in common, and the wavelength ⁇ from the first semiconductor laser ⁇ is provided.
- the chromatic aberration is corrected for the first light beam
- a diffractive structure is provided in the second collimator DPLCL through which only the light beam of the wavelength ⁇ 2 from the second semiconductor laser DHL passes, and the chromatic aberration is corrected for the light beam. 62).
- the first beam shaper BSE is disposed between the first collimator APLCL and the first semiconductor laser AL on the optical path through which the light beam of wavelength; I1 passes.
- the beam shaping of the light beam from the first semiconductor laser A is performed.
- a diffractive structure is provided in the first beam shaper BS ⁇ or the collimator AP LCL through which only the light beam of wavelength ⁇ 1 passes, and the light beam of wavelength: 1 Chromatic aberration correction may be performed.
- FIG. 13 shows the recording of information on all of high-density DVDs (also called first optical discs), conventional DVDs (also called second optical discs), and CDs (also called third optical discs).
- FIG. 21 is a schematic configuration diagram of an optical information recording / reproducing device or an optical pickup device according to a twelfth embodiment capable of reproducing. It should be noted that, in the present embodiment, the beam from the second semiconductor laser DL is beam-shaped by the second beam shaper B SE 2 instead of the second semiconductor laser of the holo laser in the embodiment of FIG. However, the difference is that the light is reflected by the 1/4 wavelength plate F and incident on the second collimator DP LCA.
- Second de The reflected light from the disk DSK passes through the 1/4 wavelength plate HF via the second collimator DP LCA and is received by the photodetector DS. Further, a diffraction structure is provided in the second beam shaper BSE2 to perform chromatic aberration correction on the light beam of wavelength ⁇ 2.
- the other points are the same as in the embodiment (including the modified example) in FIG. 12, and the description is omitted.
- an example suitable for the above-described embodiment will be described.
- Both surfaces of the objective lens are aspherical surfaces represented by [Equation 1].
- ⁇ is the axis in the optical axis direction
- h is the height from the optical axis
- r is the paraxial radius of curvature
- K is the conic coefficient
- a 2 i is the aspherical coefficient.
- a diffractive structure is integrally formed on the surface of the aspherical surface on the light source side of the objective lens.
- This diffractive structure is represented by [Equation 2] with the unit being mm by the optical path difference function ⁇ with respect to the blazed wavelength;
- This second-order coefficient indicates the paraxial power of the diffraction part.
- the spherical aberration can be controlled by a coefficient other than the second order, for example, a fourth order or sixth order coefficient.
- controllable means that the spherical aberration of the refraction portion is given a spherical aberration of the opposite characteristic by the diffraction portion to capture spherical aberration as a total, or the wavelength dependence of the diffraction portion is utilized by utilizing the wavelength dependence of the diffraction portion.
- spherical aberration can be corrected or flare can be generated.
- the spherical aberration at the time of temperature change can be considered as the total of the temperature change of the spherical aberration of the refraction part and the spherical aberration change of the diffraction part.
- the brazing wavelength ⁇ B is set to 1 mm.
- Table 1 shows lens data of an optical element (objective lens) which is a preferred example of the embodiment described above.
- a diffractive structure is provided in a region through which light beams from the first semiconductor laser, the second semiconductor laser, and the third semiconductor laser pass (common region).
- such a diffractive structure has optical characteristics that when the light source wavelength changes so as to be longer, the spherical aberration of the light beam passing therethrough is further reduced.
- the present embodiment corresponds to the optical elements described in the items 6 and 7.
- a power of 10 for example, 2.5 X 10-3
- E for example, 2.5 XE-3
- Image-side numerical aperture NA1 0.65 NA2: 0.65 NA2: 0.45
- Table 2 shows lens data of an optical element (objective lens) which is a preferred example of the embodiment described above.
- a diffraction structure is provided in a region through which light beams from the first semiconductor laser, the second semiconductor laser, and the third semiconductor laser pass (common region).
- a powerful diffractive structure has optical characteristics that, when the light source wavelength changes so as to become longer, the spherical aberration of the light beam passing therethrough becomes lower. This embodiment corresponds to the optical element described in 11 above. Table 2
- di represents the displacement from the i-th surface to the (i + 1) -th surface.
- d2 'and d3' represent displacements from the second surface to the second 'surface and from the third surface to the third' surface, respectively.
- Table 3 shows lens data of an optical element (objective lens) which is a preferred example of the embodiment described above.
- a diffraction structure is provided in a region through which light beams from the first semiconductor laser, the second semiconductor laser, and the third semiconductor laser pass (common region). Further, such a diffractive structure has optical characteristics that when the light source wavelength changes so as to become longer, the spherical aberration of the light beam passing through the light source becomes lower.
- This embodiment corresponds to the optical element described in 11 above. Table 3
- n 2 (n 1 D) 4th order that exhibits the maximum diffraction efficiency when the light beam from the second semiconductor laser passes through the diffraction structure
- Table 4 shows lens data of an optical element (objective lens) which is a preferred example of the embodiment described above.
- a diffraction structure is provided in a region through which light beams from the first semiconductor laser, the second semiconductor laser, and the third semiconductor laser pass (common region).
- such a diffractive structure has optical characteristics that when the light source wavelength changes so as to be longer, the spherical aberration of the light beam passing therethrough is further reduced.
- This embodiment corresponds to the optical element described in 11 above. Table 4
- Second semiconductor laser light source wavelength 2: 65 nm
- Table 5 shows lens data of an optical element (objective lens) which is a preferred example of the embodiment described above.
- the first diffraction structure is located in the area where the light beams from the first semiconductor laser, the second semiconductor laser, and the third semiconductor laser pass (referred to as the HD-D VDZDVDZCD common area).
- a second diffraction structure is provided in a region through which light beams from the first semiconductor laser and the second semiconductor laser pass (referred to as an HD-DVDZDVD shared region).
- This embodiment corresponds to the optical element for an optical pick-up device described in item 32.
- di represents the displacement from the i-th surface to the (i + 1) -th surface.
- d2 represents the displacement from the second surface to the second' surface.
- Table 6 shows a diffraction efficiency table of the objective lens according to the present example.
- Table 6 the first diffraction structure designed so that the second-order diffracted light becomes 100% when a light flux with a wavelength of 420 nm passes in the high-density DVDZDVDZCD common area is shown in Table 6 for each optical information recording medium. It shows the diffraction efficiency when the light flux of the wavelength used passes through, and when the light flux of wavelength 42 O nm passes in the high-density DVD / DVD common area, the second-order diffracted light becomes 100%.
- Table 6 shows the diffraction efficiency when a light beam having a wavelength used for each optical information recording medium shown in Table 6 passes through the second diffraction structure designed as described above. [Table 6]
- FIGS. 14 to 16 show the maximum diffraction efficiency in the objective lens of the present embodiment.
- Table 7 shows optical elements (examples) suitable for the embodiment corresponding to the items 20 and 55.
- di represents the displacement from the i-th surface to the (i + 1) -th surface.
- d2 represents the displacement from the second surface to the second' surface.
- Order n 2 (11 ID): 4th order that exhibits maximum diffraction efficiency when the light beam from the second semiconductor laser passes through the first diffraction structure
- an optical element and a coupling for an optical pickup device capable of appropriately recording and / or reproducing information on all of a high-density DVD and conventional DV D and CD while securing a sufficient spot light amount.
- a lens and an optical pickup device can be provided.
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Abstract
Description
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AU2003280563A AU2003280563A1 (en) | 2002-10-18 | 2003-10-16 | Optical pickup device-use optical element, coupling lens and optical pickup device |
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JP2003117207A JP2004288346A (ja) | 2002-10-18 | 2003-04-22 | 光ピックアップ装置用の光学素子、カップリングレンズ及び光ピックアップ装置 |
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EP (1) | EP1411506A3 (ja) |
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KR (1) | KR101014930B1 (ja) |
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JP2008123659A (ja) * | 2006-10-17 | 2008-05-29 | Pentax Corp | 光情報記録再生装置用対物レンズおよび光情報記録再生装置 |
US7778139B2 (en) | 2006-10-17 | 2010-08-17 | Hoya Corporation | Optical information recording/reproducing device and objective lens for the same |
CA2699752C (en) * | 2007-10-15 | 2013-05-28 | Jaybeam Wireless | Base station antenna with beam shaping structures |
JP5584552B2 (ja) * | 2009-12-21 | 2014-09-03 | Hoya株式会社 | 光情報記録再生装置用対物レンズ、及び光情報記録再生装置 |
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JP2002298422A (ja) * | 2001-03-30 | 2002-10-11 | Asahi Optical Co Ltd | 光ヘッド用対物レンズ |
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JPH1011794A (ja) * | 1996-06-27 | 1998-01-16 | Kenwood Corp | 光ピックアップ |
JP3301765B2 (ja) * | 1996-10-31 | 2002-07-15 | 三洋電機株式会社 | 光ピックアップ装置 |
CN1123874C (zh) * | 1997-05-07 | 2003-10-08 | 索尼株式会社 | 光拾取装置 |
US6834036B1 (en) * | 1998-10-28 | 2004-12-21 | Matsushita Electric Industrial Co., Ltd. | Optical head for a plurality of types of information recording media |
JP3976457B2 (ja) * | 1998-10-28 | 2007-09-19 | 松下電器産業株式会社 | 光学ヘッド |
JP2001093179A (ja) * | 1999-09-21 | 2001-04-06 | Pioneer Electronic Corp | 光ピックアップ |
JP3689328B2 (ja) * | 1999-12-28 | 2005-08-31 | ペンタックス株式会社 | 光ヘッド用対物レンズ |
TW490589B (en) * | 2000-05-24 | 2002-06-11 | Konishiroku Photo Ind | Optical pickup apparatus, objective lens, apparatus for reproducing and/or recording optical information recording medium |
JP4131366B2 (ja) * | 2000-10-30 | 2008-08-13 | コニカミノルタホールディングス株式会社 | 対物レンズ、光ピックアップ装置及び記録・再生装置 |
US7206276B2 (en) * | 2001-10-12 | 2007-04-17 | Konica Corporation | Objective lens, optical element, optical pick-up apparatus and optical information recording and/or reproducing apparatus equipped therewith |
JP2007273085A (ja) * | 2002-10-18 | 2007-10-18 | Konica Minolta Holdings Inc | 光ピックアップ装置用の光学素子、カップリングレンズ及び光ピックアップ装置 |
-
2003
- 2003-04-22 JP JP2003117207A patent/JP2004288346A/ja active Pending
- 2003-10-10 EP EP03256408A patent/EP1411506A3/en not_active Withdrawn
- 2003-10-14 TW TW092128435A patent/TWI270068B/zh not_active IP Right Cessation
- 2003-10-15 US US10/684,461 patent/US20040156301A1/en not_active Abandoned
- 2003-10-16 KR KR1020057006564A patent/KR101014930B1/ko not_active IP Right Cessation
- 2003-10-16 WO PCT/JP2003/013224 patent/WO2004036567A1/ja active Application Filing
- 2003-10-16 AU AU2003280563A patent/AU2003280563A1/en not_active Abandoned
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002298422A (ja) * | 2001-03-30 | 2002-10-11 | Asahi Optical Co Ltd | 光ヘッド用対物レンズ |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN100397508C (zh) * | 2004-11-22 | 2008-06-25 | 日立视听媒介电子股份有限公司 | 光学头及使用该光学头的光学信息记录再生装置 |
Also Published As
Publication number | Publication date |
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KR20050060096A (ko) | 2005-06-21 |
KR101014930B1 (ko) | 2011-02-15 |
AU2003280563A1 (en) | 2004-05-04 |
TWI270068B (en) | 2007-01-01 |
JP2004288346A (ja) | 2004-10-14 |
EP1411506A3 (en) | 2008-02-13 |
EP1411506A2 (en) | 2004-04-21 |
US20040156301A1 (en) | 2004-08-12 |
TW200409112A (en) | 2004-06-01 |
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