WO2013147014A1 - Lentille de focalisation, dispositif de tête de lecture optique, et appareil optique d'enregistrement et de reproduction d'informations - Google Patents

Lentille de focalisation, dispositif de tête de lecture optique, et appareil optique d'enregistrement et de reproduction d'informations Download PDF

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Publication number
WO2013147014A1
WO2013147014A1 PCT/JP2013/059236 JP2013059236W WO2013147014A1 WO 2013147014 A1 WO2013147014 A1 WO 2013147014A1 JP 2013059236 W JP2013059236 W JP 2013059236W WO 2013147014 A1 WO2013147014 A1 WO 2013147014A1
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Prior art keywords
objective lens
light
basic structure
light beam
dvd
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PCT/JP2013/059236
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English (en)
Japanese (ja)
Inventor
中村健太郎
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コニカミノルタ株式会社
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Application filed by コニカミノルタ株式会社 filed Critical コニカミノルタ株式会社
Priority to CN201380014749.5A priority Critical patent/CN104254888B/zh
Priority to JP2014508026A priority patent/JP5963120B2/ja
Publication of WO2013147014A1 publication Critical patent/WO2013147014A1/fr

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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
    • 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
    • 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
    • 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 objective lens for an optical pickup device, an optical pickup device, and an optical information recording / reproducing device capable of recording and / or reproducing (recording / reproducing) information interchangeably for different types of optical discs.
  • BD Blu-ray Disc
  • BD is an example of an optical disc that uses an NA 0.85 objective lens as described above. Since the coma generated due to the tilt of the optical disk increases, BD has a thinner protective substrate (0.1 mm compared to 0.6 mm for DVD) and reduces the amount of coma aberration compared to the case of DVD. is doing.
  • Patent Document 1 discloses a lens tilt / disc tilt sensitivity ratio in an objective lens of an optical pickup device capable of recording / reproducing information on three different types of optical discs from the viewpoint of coma aberration tilt correction. It has been proposed to be greater than 1.
  • Patent Document 1 targets HD DVDs instead of BDs, and since both have different specifications such as protective substrate thickness and NA, such information is immediately compatible with BD / DVD / CD. There is a problem that it cannot be applied to a 3-compatible objective lens that is commonly used in an optical pickup device capable of recording / reproducing.
  • An objective lens used in an optical pickup device for recording and / or reproducing information on a CD having a protective substrate having a thickness of t3 (t2 ⁇ t3) The objective lens is a single lens, and the optical surface of the objective lens has at least a central region, an intermediate region around the central region, and a peripheral region around the intermediate region, The objective lens condenses the first light flux that passes through the central region so that information can be recorded and / or reproduced on the information recording surface of the BD, and the second light flux that passes through the central region.
  • the objective lens condenses the first light flux passing through the intermediate area so that information can be recorded and / or reproduced on the information recording surface of the BD, and the second light flux passes through the intermediate area. Is recorded on the information recording surface of the DVD so that information can be recorded and / or reproduced, and the third light flux passing through the intermediate region is recorded and / or recorded on the information recording surface of the CD.
  • the objective lens condenses the first light flux passing through the peripheral area so that information can be recorded and / or reproduced on the information recording surface of the BD, and the second light flux passes through the peripheral area. Is recorded on the information recording surface of the DVD so that information can be recorded and / or reproduced, and the third light flux passing through the peripheral area is recorded on the information recording surface of the CD. And / or do not collect light for playback The following formula is satisfied.
  • the fact that the DVD lens tilt sensitivity is small as described above with respect to the BD means that a large coma aberration does not occur even when the lens is tilted. Then, even after the BD skew adjustment, sufficient correction cannot be performed when using the DVD, and a large residual coma aberration occurs. Therefore, it becomes difficult to perform skew adjustment.
  • the objective lens according to the first or second aspect wherein the central region has a first optical path difference providing structure, and the first optical path difference providing structure is a blaze type opposite to each other.
  • the intermediate region has a second optical path difference providing structure,
  • the second optical path difference providing structure is a structure in which at least a third basic structure and a fourth basic structure that are blazed in opposite directions are overlapped with each other.
  • the objective lens according to the third aspect wherein the first basic structure converts the first-order diffracted light amount of the first light beam that has passed through the first basic structure into any other order of diffraction.
  • the first-order diffracted light amount of the second light beam that has passed through the first basic structure is made larger than the diffracted light amount of any other order, and the first-order of the third light beam that has passed through the first basic structure.
  • the second basic structure makes the second-order diffracted light amount of the first light beam that has passed through the second basic structure larger than any other order of diffracted light amount, and 1 of the second light beam that has passed through the second basic structure.
  • Making the next diffracted light quantity larger than any other order diffracted light quantity making the first order diffracted light quantity of the third light flux that has passed through the second basic structure larger than any other order diffracted light quantity
  • the third basic structure makes the first-order diffracted light quantity of the first light beam that has passed through the third basic structure larger than any other order of diffracted light quantity, so that 1 of the second light flux that has passed through the third basic structure.
  • the second-order diffracted light amount of the first light beam that has passed through the fourth basic structure is made larger than any other order of diffracted light amount, and 1st of the second light beam that has passed through the fourth basic structure. It is characterized in that the next diffracted light quantity is made larger than any other order diffracted light quantity.
  • the objective lens according to claim 5 is the invention according to claim 3 or 4, wherein the second optical path difference providing structure is a structure in which at least the third foundation structure, the fourth foundation structure, and the fifth foundation structure are overlapped.
  • the 0th-order diffracted light quantity of the first light flux that has passed through the fifth basic structure is made larger than any other order diffracted light quantity
  • the second basic structure has passed through the fifth basic structure.
  • the 0th-order diffracted light amount of the light beam is made larger than any other order diffracted light amount
  • the ⁇ 1st-order diffracted light amount of the third light beam that has passed through the fifth basic structure is made larger than any other order diffracted light amount. It is characterized by that.
  • the objective lens described in claim 6 is characterized in that, in the invention described in any one of claims 1 to 5, the following expression is satisfied. 0.8 ⁇ d / f ⁇ 1.5 (13) However, d: thickness of the objective lens on the optical axis (mm) f: Focal length (mm) of the objective lens in the first light flux
  • the objective lens When dealing with a short-wavelength, high-NA optical disk such as BD, the objective lens tends to generate astigmatism and decentration coma, but conditional expression (13) By satisfying this, it is possible to suppress the occurrence of astigmatism and decentration coma.
  • the objective lens according to claim 7 is the invention according to any one of claims 1 to 6, 0 ⁇ CM3 ( ⁇ 1) ⁇ 0.030, and When ⁇ 0.0150 ⁇ CM3 ( ⁇ 2) ⁇ 0.0150, the following expression is satisfied. 0.10 ⁇ LCAM (BD) ⁇ 0.29 (31) ⁇ 0.09 ⁇ DCAM (DVD) ⁇ 0.31 (32)
  • An optical pickup device includes the objective lens according to any one of the first to eighth aspects.
  • the optical pickup device has at least three light sources: a first light source, a second light source, and a third light source. Furthermore, the optical pickup device of the present invention condenses the first light beam on the information recording surface of the BD, condenses the second light beam on the information recording surface of the DVD, and focuses the third light beam on the information recording surface of the CD.
  • the optical pickup device of the present invention includes a light receiving element that receives a reflected light beam from an information recording surface of a BD, DVD, or CD.
  • BD means that information is recorded / reproduced by a light beam having a wavelength of about 390 to 420 nm and an objective lens having an NA of about 0.8 to 0.9, and the thickness of the protective substrate is 0.05 to 0.00.
  • It is a generic term for a BD series optical disc of about 125 mm, and includes a BD having only a single information recording layer, a BD having two or more information recording layers, and the like.
  • DVD is a general term for DVD series optical discs in which information is recorded / reproduced by an objective lens having an NA of about 0.60 to 0.67 and the thickness of the protective substrate is about 0.6 mm.
  • CD is a general term for CD series optical discs in which information is recorded / reproduced by an objective lens having an NA of about 0.45 to 0.51 and the thickness of the protective substrate is about 1.2 mm.
  • the recording density the recording density of BD is the highest, followed by the order of DVD and CD.
  • the first wavelength ⁇ 1 of the first light source is 390 nm or more and 420 nm or less
  • the second wavelength ⁇ 2 of the second light source is 630 nm or more and 670 nm or less
  • the third wavelength ⁇ 3 of the third light source is 760 nm or more and 820 nm or less. It is.
  • a photodetector such as a photodiode is preferably used.
  • Light reflected on the information recording surface of the optical disc enters the light receiving element, and a read signal of information recorded on each optical disc is obtained using the output signal. Furthermore, it detects the change in the light amount due to the spot shape change and position change on the light receiving element, performs focus detection and track detection, and based on this detection, the objective lens can be moved for focusing and tracking I can do it.
  • the light receiving element may comprise a plurality of photodetectors.
  • the light receiving element may have a main photodetector and a sub photodetector.
  • an alicyclic hydrocarbon-based polymer material such as a cyclic olefin-based resin material
  • the resin material has a refractive index within a range of 1.54 to 1.60 at a temperature of 25 ° C. with respect to a wavelength of 405 nm, and a wavelength of 405 nm associated with a temperature change within a temperature range of ⁇ 5 ° C. to 70 ° C.
  • the refractive index change rate dN / dT (° C.
  • the coupling lens is also a plastic lens.
  • R 1 to R 18 , R a and R b are each independently a hydrogen atom, A halogen atom or a hydrocarbon group, R 15 to R 18 may be bonded to each other to form a monocycle or polycycle, and the monocycle or polycycle in parentheses may have a double bond Alternatively, R 15 and R 16 , or R 17 and R 18 may form an alkylidene group.
  • R 19 to R 26 each independently represents a hydrogen atom, a halogen atom or a hydrocarbon group.
  • the following additives may be added.
  • phenol-based stabilizer conventionally known ones can be used.
  • 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate
  • 2 4-di-t-amyl-6- (1- (3,5-di-t-amyl-2-hydroxyphenyl) ethyl) phenyl acrylate and the like
  • JP-A Nos. 63-179953 and 1-168643 JP-A Nos. 63-179953 and 1-168643.
  • Phenyl) phosphite tris (dinonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, 10- (3,5-di-t-butyl-4-hydroxybenzyl) -9 Monophosphite compounds such as 1,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tridecyl) Phosphite), 4,4 'isopropylidene-bis (phenyl-di-alkyl (C12-C15)) Fight) and the like diphosphite compounds such as.
  • monophosphite compounds are preferable, and tris (nonylphenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite and the like are particularly preferable.
  • each of these stabilizers is appropriately selected within a range not to impair the purpose of the present invention, but is usually 0.01 to 2 parts by mass with respect to 100 parts by mass of the alicyclic hydrocarbon-based copolymer, The amount is preferably 0.01 to 1 part by mass.
  • a surfactant is a compound having a hydrophilic group and a hydrophobic group in the same molecule.
  • the surfactant can prevent white turbidity of the resin composition by adjusting the rate of moisture adhesion to the resin surface and the rate of moisture evaporation from the surface.
  • hydrophilic group of the surfactant examples include a hydroxy group, a hydroxyalkyl group having 1 or more carbon atoms, a hydroxyl group, a carbonyl group, an ester group, an amino group, an amide group, an ammonium salt, a thiol, a sulfonate, A phosphate, a polyalkylene glycol group, etc. are mentioned.
  • the amino group may be primary, secondary, or tertiary.
  • the surfactant is added to 100 parts by mass of the alicyclic hydrocarbon-based polymer.
  • the addition amount of the surfactant is more preferably 0.05 to 5 parts by mass, still more preferably 0.3 to 3 parts by mass with respect to 100 parts by mass of the alicyclic hydrocarbon-based polymer.
  • Plasticizer The plasticizer is added as necessary to adjust the melt index of the copolymer.
  • Plasticizers include bis (2-ethylhexyl) adipate, bis (2-butoxyethyl) adipate, bis (2-ethylhexyl) azelate, dipropylene glycol dibenzoate, tri-n-butyl citrate, tricitrate citrate -N-butylacetyl, epoxidized soybean oil, 2-ethylhexyl epoxidized tall oil, chlorinated paraffin, tri-2-ethylhexyl phosphate, tricresyl phosphate, t-butylphenyl phosphate, tri-2-ethylhexyl phosphate Diphenyl, dibutyl phthalate, diisohexyl phthalate, diheptyl phthalate, dinonyl phthalate, diundecyl phthalate, di-2-ethylhexyl phthalate, diisononyl phthalate, diisode
  • the intermediate area of the objective lens is used for BD / DVD recording / reproduction and can be said to be a BD / DVD shared area not used for CD recording / reproduction. That is, the objective lens condenses the first light flux passing through the intermediate area so that information can be recorded / reproduced on the information recording surface of the BD, and the second light flux passing through the intermediate area is recorded as information recording on the DVD. Light is collected so that information can be recorded / reproduced on the surface.
  • the third light flux passing through the intermediate region is not condensed so that information can be recorded / reproduced on the information recording surface of the CD.
  • the third light flux passing through the intermediate region of the objective lens preferably forms a flare on the information recording surface of the CD. As shown in FIG.
  • optical path difference providing structure referred to in this specification is a general term for structures that add an optical path difference to an incident light beam.
  • the optical path difference providing structure also includes a phase difference providing structure for providing a phase difference.
  • the phase difference providing structure includes a diffractive structure.
  • the optical path difference providing structure of the present invention is preferably a diffractive structure.
  • the optical path difference providing structure has a step, preferably a plurality of steps. This step adds an optical path difference and / or phase difference to the incident light flux.
  • the optical path difference added by the optical path difference providing structure may be an integer multiple of the wavelength of the incident light beam or a non-integer multiple of the wavelength of the incident light beam.
  • the steps may be arranged with a periodic interval in the direction perpendicular to the optical axis, or may be arranged with a non-periodic interval in the direction perpendicular to the optical axis.
  • the objective lens provided with the optical path difference providing structure is a single aspherical lens
  • the incident angle of the light flux to the objective lens differs depending on the height from the optical axis.
  • Each will be slightly different.
  • the objective lens is a single-lens aspherical convex lens, even if it is an optical path difference providing structure that provides the same optical path difference, generally the distance from the optical axis tends to increase.
  • the step amount of the first basic structure does not become too large, so that the manufacture is facilitated, and the light quantity loss due to the manufacturing error can be suppressed, and the wavelength It is preferable because the diffraction efficiency fluctuation at the time of fluctuation can be reduced.
  • the first basic structure preferably has a positive diffractive power, so that a working distance when using a CD can be secured even for an objective lens having a large axial thickness such as an objective lens for BD / DVD / CD.
  • the second basic structure preferably has a negative diffraction power. As described above, since both the first basic structure and the second basic structure have diffraction power, when using an optical disk having a plurality of information recording surfaces, unnecessary light reflected by the information recording surface which is not a recording / reproducing object is required light. It is preferable because it can be further away from the center.
  • the spherical aberration changes in the undercorrection (under) direction, and the incident light is incident on the other side.
  • the spherical aberration may be changed in the overcorrection (over) direction.
  • the amount of change in the third-order spherical aberration when the wavelength of the first light beam changes by +5 nm is -10 m ⁇ rms or more and +10 m ⁇ rms or less. More preferably.
  • the amount of change in the fifth-order spherical aberration when the wavelength of the first light beam changes by +5 nm is -20 m ⁇ rms or more and 20 m ⁇ rms or less. It is preferable that More preferably, it is ⁇ 10 m ⁇ rms or more and +10 m ⁇ rms or less.
  • LTCM3 ( ⁇ 1) / LTCM3 ( ⁇ 2) ⁇ 10.0
  • LTCM3 ( ⁇ 1) indicates the lens tilt third-order coma aberration ( ⁇ rms / deg.) Of the objective lens tilted by a unit angle when the first light beam is used
  • LTCM3 ( ⁇ 2) indicates only the unit angle when the second light beam is used.
  • the lens tilt third-order coma aberration ( ⁇ rms / deg.) Of the tilted objective lens is shown.
  • the first light beam, the second light beam, and the third light beam are incident on the objective lens as parallel light or substantially parallel light. As a result, it is possible to prevent coma from occurring even during tracking.
  • the imaging magnification m1 of the objective lens when the first light beam is incident on the objective lens satisfy the following formula (9). -0.01 ⁇ m1 ⁇ 0.01 (9)
  • the imaging magnification m2 of the objective lens when the second light beam is incident on the objective lens satisfies the following formula (10). Is preferred. -0.01 ⁇ m2 ⁇ 0.01 (10)
  • the coupling lens may have an actuator through which at least the first light beam and the second light beam pass and move the coupling lens in the optical axis direction.
  • the BD has a plurality of information recording surfaces such as two layers or three layers or more
  • the difference in the thickness of the transparent substrate is required. Therefore, spherical aberration generated due to the difference in thickness must be corrected. It is conceivable to correct the generated spherical aberration by moving the coupling lens in the optical axis direction and changing the magnification of the objective lens. Further, spherical aberration that occurs when the temperature or wavelength changes can be corrected by moving the coupling lens in the optical axis direction and changing the magnification of the objective lens.
  • the wavelength of the incident light beam in one of the third basic structure and the fourth basic structure constituting the second optical path difference providing structure of the objective lens So that the spherical aberration changes in the direction of insufficient correction, and on the other side, the spherical aberration changes in the direction of overcorrection when the wavelength of the incident light beam changes longer.
  • both the temperature characteristic and the wavelength characteristic when using the DVD can be improved, and as a result, when using the DVD, the position of the coupling lens in the optical axis direction is fixed when the second light beam passes.
  • An optical information recording / reproducing apparatus includes an optical disc drive apparatus having the above-described optical pickup apparatus.
  • the objective lens for optical pick-up apparatuses which can be used for a thin optical pick-up apparatus, and can record / reproduce information appropriately with respect to BD, DVD, CD, optical pick-up apparatus, and optical information recording
  • a playback device can be provided.
  • FIG. 1 It is an axial direction sectional drawing which shows the example of an optical path difference providing structure, (a), (b) shows the example of a blazed type structure, (c), (d) shows the example of a step type structure.
  • (A) shows a state in which the step is directed in the direction of the optical axis
  • (b) is a diagram showing a state in which the step is directed in a direction opposite to the optical axis.
  • (A) shows a shape in which the step is in the direction of the optical axis in the vicinity of the optical axis, but changes in the middle, and in the vicinity of the intermediate region, the step is in the direction opposite to the optical axis.
  • FIG. 4 is a diagram showing a shape in which a step is directed in the opposite direction to the optical axis in the vicinity of the axis, but is switched in the middle, and the step is directed toward the optical axis in the vicinity of the intermediate region.
  • It is a conceptual diagram of a 1st optical path difference providing structure, (a), (b), (c), (d) shows the example of a 1st optical path difference providing structure.
  • It is a schematic diagram of a preferable objective lens. It is a figure which shows schematically the structure of optical pick-up apparatus PU1 of this Embodiment which can record and / or reproduce
  • the first optical path difference providing structure already described in detail is formed in the center region CN
  • the second optical path difference providing structure already described in detail is formed in the intermediate region MD.
  • a third optical path difference providing structure is formed in the peripheral region OT.
  • the third optical path difference providing structure is a blazed diffractive structure.
  • the objective lens of the present embodiment is a plastic lens.
  • the step is directed in the direction opposite to the optical axis, and in the second basic structure, the second-order diffracted light quantity of the first light beam that has passed through the second basic structure is greater than the diffracted light quantity of any other order. And the primary of the second light flux that has passed through the second basic structure.
  • the amount of diffracted light is made larger than the amount of diffracted light of any other order, the amount of first order diffracted light of the third light beam passing through the second basic structure is made larger than the amount of diffracted light of any other order, and the following equation is satisfied .
  • the linearly polarized light is converted into circularly polarized light by the ⁇ / 4 wavelength plate QWP, and is incident on the objective lens OL.
  • the light beam collected by the central region of the objective lens OL (the light beam that has passed through the intermediate region and the peripheral region is flared and forms a spot peripheral part) is recorded on the CD through the protective substrate PL3. It becomes a spot formed on the surface RL3.
  • the reflected light beam modulated by the information pits on the information recording surface RL3 passes through the objective lens OL again, is converted from circularly polarized light to linearly polarized light by the ⁇ / 4 wave plate QWP, and is converged by the collimating lens COL, The light is reflected by the polarization beam splitter BS and converges on the light receiving surface of the light receiving element PD via the sensor lens SEN. And the information recorded on CD can be read using the output signal of light receiving element PD.
  • Example 1 The objective lens of Example 1 is a plastic single lens. Table 1 shows lens data.
  • a conceptual diagram of the first optical path difference providing structure of the first embodiment is shown in FIG. 8A (FIG. 8A is a conceptual diagram different from the actual shape of the first embodiment).
  • the (1/1/1) blaze is added to the second basic structure BS2 that is a (2/1/1) blaze-type diffraction structure in the entire central region.
  • the first basic structure BS1 which is a diffractive structure of the mold, is an optical path difference providing structure that is overlapped.
  • Example 3 The objective lens of Example 3 is a plastic single lens. Table 3 shows lens data.
  • a conceptual diagram of the first optical path difference providing structure of the third embodiment is shown in FIG. 8A (FIG. 8A is a conceptual diagram different from the actual shape of the third embodiment).
  • the (1/1/1) blaze is added to the second basic structure BS2 which is a (2/1/1) blazed diffraction structure in the entire central region.
  • the first basic structure BS1 which is a diffractive structure of the mold, is an optical path difference providing structure that is overlapped.
  • the step of the second foundation structure BS2 faces the direction of the optical axis OA
  • the step of the first foundation structure BS1 faces the direction opposite to the optical axis OA
  • the second optical path difference providing structure of Example 1 has (1/1/1) the fourth basic structure BS4 that is a blazed diffraction structure of (2/1/1) in the entire intermediate region.
  • This is an optical path difference providing structure in which the third basic structure BS3, which is a blazed diffraction structure, is overlapped.
  • the step of the fourth foundation structure BS4 faces the direction of the optical axis OA
  • the step of the third foundation structure BS3 faces the direction opposite to the optical axis OA.
  • Example 6 The objective lens of Example 6 is a plastic single lens. Table 6 shows lens data.
  • a conceptual diagram of the first optical path difference providing structure of the sixth embodiment is shown in FIG. 8A (FIG. 8A is a conceptual diagram different from the actual shape of the sixth embodiment).
  • the (1/1/1) blaze is added to the second basic structure BS2 that is a (2/1/1) blaze-type diffraction structure in the entire central region.
  • the first basic structure BS1 which is a diffractive structure of the mold, is an optical path difference providing structure that is overlapped.
  • the step of the second foundation structure BS2 faces the direction of the optical axis OA
  • the step of the first foundation structure BS1 faces the direction opposite to the optical axis OA
  • the second optical path difference providing structure of Example 6 is (1/1/1) in the fourth basic structure BS4 which is a blazed diffraction structure of (2/1/1) in the entire intermediate region.
  • the level difference of the fourth foundation structure BS4 faces the direction of the optical axis OA
  • the level difference of the third foundation structure BS3 faces the direction opposite to the optical axis OA.
  • Patterns (1) and (2) in Table 8 have a residual coma aberration of BD by molding of 0.030 ⁇ rms, a residual coma aberration of DVD by molding of 0.015 ⁇ rms, and a residual coma aberration of CD by molding of 0.000 ⁇ rms.
  • the residual coma aberration of the BD and the residual coma aberration of the DVD occur in the same direction, and in the pattern (2), they occur in the reverse direction.
  • the residual coma aberration of the BD by molding is 0.020 ⁇ rms
  • the residual coma aberration of the DVD by molding is 0.015 ⁇ rms
  • the residual coma aberration of the CD by molding is 0.000 ⁇ rms
  • Pattern (3) occurs in the same direction
  • pattern (4) occurs in the reverse direction.
  • Table 8 shows the skew adjustment result of each pattern.
  • the same pattern as in Table 8 was examined for the residual coma aberration and the DVD residual coma aberration after skew adjustment.
  • the residual coma aberration of the BD by molding is ⁇ 0.030 ⁇ rms
  • the residual coma aberration of the DVD by molding is 0.015 ⁇ rms
  • the residual coma aberration of the CD by molding is 0.000 ⁇ rms.
  • the pattern (1) the residual coma aberration of the BD and the residual coma aberration of the DVD are generated in the same direction
  • the pattern (2) is generated in the reverse direction.
  • Table 11 collectively shows the maximum value and the minimum value of each value of Examples 1 to 6 with respect to the skew adjustment result for each pattern of Table 10. Even in the case of Table 10, when the conditional expression (12) of the present invention is satisfied, the residual coma aberration of the DVD after BD skew adjustment is 0.030 ⁇ rms in absolute value, and the residual coma aberration of the BD by molding ( ⁇ 0. (030 ⁇ rms).

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  • Optical Recording Or Reproduction (AREA)

Abstract

Une lentille de focalisation qui est utilisée dans un dispositif de tête de lecture optique selon la présente invention comprend une première source de lumière qui émet un premier flux lumineux à une première longueur d'onde (λ1) (390 nm ≤ λ1 ≤ 420 nm), une deuxième source de lumière qui émet un deuxième flux lumineux à une deuxième longueur d'onde (λ2) (630 nm ≤ λ2 ≤ 670 nm), et une troisième source de lumière qui émet un troisième flux lumineux à une troisième longueur d'onde (λ3) (760 nm ≤ λ3 ≤ 820 nm), effectue l'enregistrement et/ou la reproduction des informations d'un CD qui comporte un substrat de protection d'une épaisseur (t1) en utilisant le premier flux lumineux, effectue l'enregistrement et/ou la reproduction des informations d'un DVD qui comporte un substrat de protection d'une épaisseur (t2) (t1 < t2) en utilisant le deuxième flux lumineux, effectue l'enregistrement et/ou la reproduction des informations d'un CD qui comporte un substrat de protection d'une épaisseur (t3) (t2 < t3) en utilisant le troisième flux lumineux, et qui satisfait à la formule suivante : 1,9 ≤ LTCM3(λ1)/LTCM3(λ2) ≤ 10,0.
PCT/JP2013/059236 2012-03-29 2013-03-28 Lentille de focalisation, dispositif de tête de lecture optique, et appareil optique d'enregistrement et de reproduction d'informations WO2013147014A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN201380014749.5A CN104254888B (zh) 2012-03-29 2013-03-28 物镜、光拾取装置以及光信息记录再现装置
JP2014508026A JP5963120B2 (ja) 2012-03-29 2013-03-28 対物レンズ、光ピックアップ装置及び光情報記録再生装置

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2012076684 2012-03-29
JP2012-076684 2012-03-29

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WO2013147014A1 true WO2013147014A1 (fr) 2013-10-03

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PCT/JP2013/059236 WO2013147014A1 (fr) 2012-03-29 2013-03-28 Lentille de focalisation, dispositif de tête de lecture optique, et appareil optique d'enregistrement et de reproduction d'informations

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JP (1) JP5963120B2 (fr)
WO (1) WO2013147014A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005108398A (ja) * 2003-09-08 2005-04-21 Ricoh Co Ltd 対物レンズ、光ピックアップ及び光情報処理装置
JP2010123214A (ja) * 2008-11-20 2010-06-03 Sony Corp 対物レンズ、光ピックアップ及び光ディスク装置
JP2012033213A (ja) * 2010-07-29 2012-02-16 Hitachi Media Electoronics Co Ltd 光学的情報記録再生装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005108398A (ja) * 2003-09-08 2005-04-21 Ricoh Co Ltd 対物レンズ、光ピックアップ及び光情報処理装置
JP2010123214A (ja) * 2008-11-20 2010-06-03 Sony Corp 対物レンズ、光ピックアップ及び光ディスク装置
JP2012033213A (ja) * 2010-07-29 2012-02-16 Hitachi Media Electoronics Co Ltd 光学的情報記録再生装置

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JP5963120B2 (ja) 2016-08-03
CN104254888A (zh) 2014-12-31
JPWO2013147014A1 (ja) 2015-12-14

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