WO2001057862A1 - Dispositif de tete optique - Google Patents
Dispositif de tete optique Download PDFInfo
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- WO2001057862A1 WO2001057862A1 PCT/JP2001/000725 JP0100725W WO0157862A1 WO 2001057862 A1 WO2001057862 A1 WO 2001057862A1 JP 0100725 W JP0100725 W JP 0100725W WO 0157862 A1 WO0157862 A1 WO 0157862A1
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- light
- head device
- reflected
- optical head
- laser
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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
- G11B7/1395—Beam splitters or combiners
-
- 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
- G11B7/1356—Double or multiple prisms, i.e. having two or more prisms in cooperation
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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
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B7/0901—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for track following only
- G11B7/0904—Dithered tracking systems
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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
- G11B7/123—Integrated head arrangements, e.g. with source and detectors mounted on the same substrate
-
- 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
- G11B7/13—Optical detectors therefor
- G11B7/131—Arrangement of detectors in a multiple array
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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
- G11B7/1359—Single prisms
-
- 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
- G11B7/1376—Collimator 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
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B7/0901—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for track following only
Definitions
- the present invention relates to an optical head device for recording or reproducing information on an information recording medium by a magneto-optical method.
- FIG. 7 is an arrangement diagram showing an optical system and an information recording medium of an optical head device according to the related art.
- a semiconductor laser element 101 and a light-receiving element 102 for a support signal for detecting a focus error signal and a tracking error signal are provided inside the semiconductor laser unit 107.
- a polarizing beam splitter 111, a collimating lens 111, and an objective lens are arranged in order from the semiconductor laser element 101 side. 1 1 3 are arranged.
- the polarizing beam splitter 111 is fixed to the upper surface of the semiconductor laser unit 107.
- a diffraction grating 109 is formed on the surface of the polarization beam splitter 111 on the semiconductor laser element 101 side.
- a light beam for the information signal is positioned beside the polarizing beam splitter 111 (to the right in FIG. 7).
- Element 104 is installed
- a Wollaston prism 116 is provided on the side face of the information beam receiving element 104 of the polarization beam splitter 111.
- Reflect light Light emitted from the semiconductor laser element 101 and reflected by the information recording medium 114 (hereinafter referred to as “return light”) passes through the objective lens 113 and the collimating lens 112 in this order, and then is polarized. It is incident on 1 1 1
- the polarized beam splitter 111 reflects a part of the return light in the direction of the Wollaston prism 116 and branches. In the Wollaston prism 1 16, the refraction index is different between the P-polarized light and the S-polarized light, so the return light incident on the Wollaston prism 1 16 has the P-polarized component in the Wollaston prism 1 16. And S-polarized light component.
- the information signal light receiving element 104 is divided into two at the positions where the information signal light separated into two components is converged as described above, and the output of the information signal light receiving element 104 is provided. An information signal is detected based on the information signal.
- return light that has passed through the polarizing beam splitter 111 as it is is diffracted by the diffraction grating 109 and then enters the light receiving element 102 for a SAP signal. Then, a focus error signal and a tracking error signal are detected based on the output from the light receiving element 102 for the servo signal.
- the light emitted from the semiconductor laser device 101 and the return light are indicated by broken lines.
- the light intensity of the light emitted from the semiconductor laser device has an emission angle dependence as shown by a curved line T in FIG. 8A. Therefore, when the objective lens 113 shifts in the radial direction of the information recording medium 114 in the above-mentioned conventional optical head device, the light intensity of the light taken into the objective lens 113 decreases. Therefore, as shown by the curve U in FIG. 8B, the signal amount of the tracking error signal is reduced, and the sampling operation becomes unstable. Disclosure of the invention
- the present invention has been made to solve the above-mentioned problems in the prior art, and has an optical system which hardly causes deterioration of the signal amount of a tracking error signal even when an objective lens shifts in a radial direction of an information recording medium. It is intended to provide an expression head device.
- a configuration of an optical head device includes: a semiconductor laser element that irradiates a laser beam onto an information recording medium; and the laser beam that reflects off the information recording medium and returns the laser beam.
- An optical head device provided with a reflecting means, wherein the reflectance of the laser light in the reflecting means increases as the laser light deviates from the optical axis of the laser light.
- the light intensity of the laser light emitted from the semiconductor laser element has an emission angle dependence that decreases as it deviates from the center of the optical axis
- the reflection means Since the reflection means has such a reflection characteristic that the reflectance of the laser beam increases as the laser beam deviates from the optical axis of the laser beam, it is possible to correct the emission angle dependence of the laser light intensity. Therefore, it is possible to suppress a decrease in the signal amount of the tracking error signal when the objective lens shifts in the radial direction of the information recording medium. As a result, the dependency of the tracking error signal intensity on the objective lens shift becomes extremely small as compared with the related art, and thus a stable servo operation can be realized.
- a light receiving element that receives the laser beam reflected by the reflection unit is further provided.
- a polarizing light splitting unit that splits the laser beam reflected by the information recording medium and returned is used as the reflecting unit.
- the polarizing light splitting means is a polarizing beam splitter. Also, this In this case, when the incident angle of the laser beam reflected by the information recording medium and returning to the reflecting surface of the polarizing branching means is 45 °, the reflectance of the P-polarized light component of the laser beam is minimum.
- the signal amount of the tracking error signal decreases when the objective lens shifts in the radial direction of the information recording medium. Can be prevented.
- the incident angle of the laser beam reflected by the information recording medium and returning to the reflection surface of the polarizing branching means is 45.
- the reflectance of the S-polarized light component of the laser light be minimized.
- the signal amount of the tracking error signal when the objective lens shifts in the radial direction of the information recording medium. can be prevented from decreasing.
- a diffractive means for branching the laser light emitted from the semiconductor laser element into a plurality of sub-beams including a preceding sub-beam and a succeeding sub-beam; Means for detecting a difference signal, wherein reflected light from the information recording medium with respect to the preceding sub-beam or the following sub-beam is reflected by the reflecting means, and the tracking error signal is detected using the reflected light.
- the dependency of the tracking error signal intensity on the objective lens shift when the objective lens shifts in the radial direction of the information recording medium becomes extremely small as compared with the related art, so that a stable support operation is achieved. Can be realized.
- a diffractive means for splitting the laser light emitted from the semiconductor laser element into a plurality of sub-beams including a preceding sub-beam and a succeeding sub-beam; Means for detecting a racking error signal;
- the reflected light from the information recording medium relating to the beam or the subsequent sub-beam is reflected by the reflecting means, and the reflected light is further branched into two light beams of a P-polarized light component and an S-polarized light component by a polarizing light branching means.
- the two light beams are detected in the same light receiving area to detect the information signal and the tracking error signal.
- FIG. 1 is an arrangement diagram showing a configuration of an optical head device according to a first embodiment of the present invention.
- FIG. 2A is a diagram showing the emission angle dependence of the light intensity of the laser light emitted from the semiconductor laser element used in the optical head device according to the first embodiment of the present invention
- FIG. 2B is the present invention
- FIG. 2C is a diagram showing the incident angle dependence of the reflectance of a polarizing beam splitter used in the optical head device according to the first embodiment of the present invention.
- FIG. 2C is an optical head according to the first embodiment of the present invention.
- FIG. 4 is a diagram showing the dependency of the tracking error signal intensity of the device on the shift of the objective lens.
- FIG. 3 is an arrangement diagram showing a configuration of an optical head device according to a second embodiment of the present invention.
- FIG. 4 is a sectional view of the optical unit shown in FIG.
- FIG. 5 is a plan view of the light receiving substrate shown in FIG.
- FIG. 6 is a partial plan view of the hologram optical element shown in FIGS.
- FIG. 7 is an arrangement diagram showing an optical system and an information recording medium of an optical head device according to the related art.
- FIG. 8A shows a semiconductor laser used in an optical head device in the prior art.
- FIG. 8B is a diagram showing the emission angle dependence of the light intensity of the laser beam emitted from the element, and
- FIG. 8B is a diagram showing the objective lens shift dependence of the tracking error signal intensity of the optical head device in the prior art.
- FIG. 1 is an arrangement diagram showing a configuration of an optical head device according to a first embodiment of the present invention.
- an information recording medium 7 for recording or reproducing information represented by, for example, a CD (compact disc) or a DVD (digital video disc).
- the laser beam emitted from the semiconductor laser element 1 is branched into a plurality of sub-beams including a preceding sub-beam and a succeeding sub-beam in order from the semiconductor laser element 1 side.
- a polarization beam splitter 14, a rising mirror 5, and an objective lens 6 are arranged.
- a beam splitter 18, a condenser lens 11, and a Wollaston prism 1 are arranged in this order from the polarizing beam splitter 14 side. 2 is located.
- a beam splitter 8 and a condenser lens 9 are arranged in this order from the polarization beam splitter 4 side.
- the polarizing beam splitter 4 has a reflecting surface whose laser light L 1 (shown by a broken line in FIG. 1) emitted from the semiconductor laser element 1 and light reflected by the information recording medium 7 (hereinafter referred to as “return light”).
- Optical axis a of L 2 (indicated by the broken line in FIG. 1) (Shown by a dashed line in Fig. 1).
- the reflection surface of the polarizing beam splitter 4 has a minimum reflectance when the incident angle of the return light L 2 is 45 °, and the incident angle of the return light L 2 Has a reflection characteristic such that the reflectance increases as the light beam deviates from 45 ° (ie, as the light beam L2 deviates from the optical axis a of the return light L2).
- the light intensity of the laser light L1 emitted from the semiconductor laser element 1 has an emission angle dependence as shown by a curve X in FIG. 2A, and the light intensity decreases as the laser light L1 deviates from the optical axis center.
- the objective lens 6 shifts in the radial direction of the information recording medium 7
- the light intensity of the laser beam L1 captured by the objective lens 6 decreases, and as a result, the tracking error signal
- the signal amount of the signal decreases, and the servo operation becomes unstable.
- the reflection surface of the polarization beam splitter 14 has a minimum reflectance when the incident angle of the return light L2 is 45 °, and the return light L2 Reflectivity as the angle of incidence of the light deviates from 45 Has a reflection characteristic such that the laser beam L 1 increases (see FIG. 2B), so that the output angle dependence of the light intensity of the laser beam L 1 emitted from the semiconductor laser element 1 can be corrected. Therefore, it is possible to suppress a decrease in the signal amount of the tracking error signal when the objective lens 6 is shifted in the radial direction of the information recording medium 7. As a result, as shown by the curve Z in Fig.
- the dependency of the tracking error signal intensity on the objective lens shift is much smaller than in the conventional case (Fig. 8B), and the servo operation becomes unstable. It will not be. Also, if the reflectance of the P-polarized light component of the return light L2 is minimized when the angle of incidence of the return light L2 on the reflecting surface of the polarizing beam splitter 4 is 45 °, the objective lens 6 can be formed. It is possible to prevent the amount of the P-polarized light component from decreasing when the information recording medium 7 is shifted in the radial direction.
- the objective lens 6 can be used. It is possible to prevent the amount of S-polarized light component from decreasing when the information recording medium 7 is shifted in the radial direction.
- the laser beam L 1 emitted from the semiconductor laser device 1 is branched into three beams of a 0th-order diffracted beam and ⁇ 1st-order folded beam when passing through a three-beam generating diffraction grating 2. Thereafter, the light enters the collimating lens 3.
- the laser beam L 1 incident on the collimating lens 3 is converted from a divergent light beam into a parallel light beam when passing through the collimating lens 3, and then passes through the polarizing beam splitter 4.
- the laser beam L 1 transmitted through the polarizing beam splitter 4 is reflected by a rising mirror 5 and then condensed on an information recording medium 7 by an objective lens 6.
- the light reflected by the information recording medium 7 returns to the light path L 2 and reverses the optical path described above. It is incident on 4. A part of the return light L 2 incident on the polarization beam splitter 4 is reflected (hereinafter, the return light L 2 reflected by the polarization beam splitter 14 is referred to as “reflected split light”). It is incident on 8.
- the light incident on the Wollaston prism 12 is separated there into a P-polarized component and an S-polarized component, and then received by the information signal light receiving element 13. Then, by differentially detecting the two lights (P-polarized light component and S-polarized light component), an information signal RF is obtained.
- the remaining part of the split light that has entered the beam splitter 18 is reflected by the beam splitter 8 and is condensed by the condensing lens 9, and then by the light-receiving element 10 for the support signal. Received.
- the focus error signal is detected by the astigmatism method, and the tracking error signal is detected by the three-beam method.
- the configuration is such that the tracking error signal is detected using the reflected split light from the polarization beam splitter 4, and as described above, the polarization beam splitter
- the reflection surface of (4) has such a reflection characteristic that the reflectance becomes minimum when the incident angle of the return light L2 is 45 °, and increases as the incident angle of the return light L2 deviates from 45 °.
- Optical head device that suppresses the signal amount of the tracking error signal when the objective lens 6 shifts in the radial direction of the information recording medium 7 and has a stable servo operation. can do.
- the tracking error is caused by the 3-beam method.
- the method of detecting a difference signal has been described as an example, but is not necessarily limited to this method.For example, a phase difference method, a push-pull method, and a differential push-pull method are used. Even in this case, the same effects as above can be obtained.
- an optical head device having an infinite optical system including the collimator lens 3 and the objective lens 6 has been described as an example, but the present invention is not necessarily limited to this configuration. Instead, for example, the same effects as described above can be obtained even when a finite optical system using only the objective lens 6 is used.
- the information signal RF is also detected using the reflected and branched light from the polarization beam splitter 4, even if the objective lens 6 is shifted in the radial direction of the information recording medium 7, the information signal RF is detected.
- the signal amount of the signal hardly deteriorates, and an information signal of good quality can be obtained.
- an example of a magneto-optical head device that separates the return light L 2 into a P-polarized component and an S-polarized component using a Wollaston prism 12 and detects an information signal is described.
- the change in the amount of light is read by receiving all the condensed light from the condensing lens 11
- the present invention can be similarly applied to an optical head device that detects an information signal. In this case, it goes without saying that a beam splitter having no polarization can be used in place of the polarization beam splitter 4.
- FIG. 3 shows a configuration of an optical head device according to a second embodiment of the present invention.
- FIG. 4 is a cross-sectional view of the optical unit shown in FIG. 3
- FIG. 5 is a plan view of the light receiving substrate shown in FIG. 4
- FIG. 6 is a partial plan view of the wedge-gram optical element shown in FIGS. FIG.
- reference numeral 7 denotes an information recording medium.
- the semiconductor laser device 1 is arranged in a concave portion formed in the light receiving substrate 23.
- light receiving elements 26, 27 and 28 and light receiving elements 29 and 30 each composed of a plurality of elements are formed.
- the light receiving element 26 is composed of six elements 26 a, 26 b, 26 c, 26 d, 26 e, and 26 f
- the light receiving element 27 is also 6 Elements 27a, 27b, 27c, 27d, 27e, and 27f
- the light-receiving element 28 is composed of two elements 2a and 28b. ing.
- FIGS. 1 the semiconductor laser device 1 is arranged in a concave portion formed in the light receiving substrate 23.
- light receiving elements 26, 27 and 28 and light receiving elements 29 and 30 each composed of a plurality of elements are formed.
- the light receiving element 26 is composed of six elements 26 a, 26 b, 26 c, 26 d, 26 e, and 26 f
- the light receiving element 27 is also 6 Elements 27a, 27b, 27
- the light-receiving substrate 23 is disposed inside a package 15 having a plurality of terminals 24, and a three-beam generation diffraction grating 18 and a diffraction Incidentally t grid 1 9 gar body formed by holographic optical element 1 6 were are arranged as cap, as shown in FIG. 6, the diffraction grating 1 9, two times with different lens effect diffraction grating region 1 9a and 19b.
- the curves and their intervals in FIG. 6 represent the approximate shape of the curve of the pitch of the diffraction grating and the intervals. As shown in FIGS.
- a composite microprism 17 in which a polarizing beam splitter 20, a reflecting mirror 21 and a Wollaston prism 22 are integrally formed is formed on the hologram optical element 16, a composite microprism 17 in which a polarizing beam splitter 20, a reflecting mirror 21 and a Wollaston prism 22 are integrally formed is formed.
- the polarizing beam splitter 20 has a reflecting surface whose laser light L 1 (shown by a broken line in FIGS. 3 and 4) and return light L 2 (shown by a broken line in FIGS. 3 and 4) emitted from the semiconductor laser element 1. Are indicated at 45 ° to the optical axis b (indicated by the dashed line in FIG. 3).
- the reflection surface of the polarizing beam splitter 20 has a minimum reflectance when the incident angle of the return light L 2 is 45 °, as shown by the curve Y in FIG. 2B, and the return light L It has such a reflection characteristic that the reflectivity increases as the incident angle of 2 deviates from 45 ° (that is, as it deviates from the optical axis b of the return light L2). This reflection characteristic can also be realized in the same manner as in the first embodiment.
- the light intensity of the laser light L1 emitted from the semiconductor laser element 1 has the same emission angle dependence as shown by the curve X in FIG. 2A, and the light intensity decreases as the laser light L1 deviates from the optical axis center. I do.
- the objective lens 6 shifts in the radial direction of the information recording medium 7
- the light intensity of the laser beam L1 captured by the objective lens 6 decreases, and as a result, the signal of the tracking error signal is reduced.
- the amount will drop and the servo operation will become unstable.
- the reflection surface of the polarizing beam splitter 20 has a minimum reflectance when the incident angle of the return light L2 is 45 °, and the incidence of the return light L2 It has reflection characteristics such that the reflectance increases as the angle deviates from 45 °, so that the output angle dependence of the light intensity of the laser beam L1 emitted from the semiconductor laser device 1 is corrected. can do.
- the dependence of the tracking error signal intensity on the objective lens shift is much smaller than in the conventional case (Fig. 8B), as shown by the curve Z in Fig. 2C. It will not be stable.
- the laser beam L 1 emitted from the semiconductor laser device 1 passes through the three-beam generation diffraction grating 18, the three beams of 0-order diffraction light and ⁇ 1st-order diffraction light are emitted.
- the light After passing through the polarizing beam splitter 20, the light enters the collimator lens 3.
- the laser beam L 1 incident on the collimating lens 3 is once converted from a divergent light beam into a parallel light beam when passing through the collimating lens 3, reflected by the rising mirror 5, and then on the information recording medium 7 by the objective lens 6. Is collected.
- the light reflected by the information recording medium 7 becomes return light L 2, reversely passes through the above-described optical path, and enters the polarization beam splitter 20 again.
- a part of the return light L2 incident on the polarization beam splitter 20 is transmitted through the polarization beam splitter 20 as it is (hereinafter, the return light L2 transmitted through the polarization beam splitter 120).
- the two diffraction grating regions 19 a and 19 b receive different diffraction 'light condensing actions.
- the main beam in the transmitted and branched light incident on the diffraction grating region 19a has its + 1st-order diffracted light incident on the elements 26d, 26e and 26f of the light receiving element 26, Light enters the elements 27a, 27b and 27c of the light receiving element 27.
- the main beam in the transmitted and branched light incident on the diffraction grating area 19 b has its + 1st-order diffracted light incident on the elements 26 a, 26 b and 26 c of the light receiving element 26,
- the folded light enters the elements 27 d, 27 e and 27 f of the light receiving element 27.
- the focus error signal FE can be detected by the D-SSD (double spot size detection, Double Spot Size Detection) method using the calculation expressed by the following [Equation 1]. [Equation 1]
- reference numeral 25 denotes a micromirror for reflecting light emitted from the semiconductor laser element 1 and guiding the reflected light toward the three-beam generation diffraction grating 18, which is diffracted by the diffraction grating 19.
- the sub-beams are omitted for simplicity.
- the remaining part of the return light L2 that has entered the polarization beam splitter 20 is reflected by the polarization beam splitter 20 (hereinafter, the return light L2 reflected by the polarization beam splitter 20).
- the light is further reflected by the reflection mirror 21 and enters the Wollaston prism 22.
- the reflected and branched light incident on the Wollaston prism 22 is separated into a P-polarized component and an S-polarized component there, and the main beam is divided into two polarized components by the two elements 28 a and 28 b of the light receiving element 28. It is received every time.
- the two sub-beams are collectively received by the light-receiving elements 29 and 30, respectively, with the P-polarized component and the S-polarized component.
- the tracking error signal TE can be detected by a three-beam method using an operation represented by the following [Equation 2].
- the information signal RF is detected using a differential operation expressed by the following [Equation 3], for example, in the case of an MD RAM disk or M ⁇ disk. (3)
- the light-receiving elements such as 29 and 28a and the reference numerals indicating the elements represent the light-receiving elements and the intensity of light incident on the elements as they are.
- the tracking error signal is detected using the reflected and branched light from the polarization beam splitter 20
- the same effect as in the above-described first embodiment can be achieved to achieve a stable optical operation of the servo operation.
- a type head device can be realized.
- the information signal RF is also detected by using the reflected and branched light from the polarization beam splitter 20, even if the objective lens 6 is shifted in the radial direction of the information recording medium 7, the signal of the information signal is detected. The quantity is hardly degraded and a good quality information signal can be obtained.
- the reflection angle of the laser beam at the reflection means increases as the laser beam deviates from the optical axis of the laser beam.
- Dependencies can be corrected. Therefore, when the objective lens shifts in the radial direction of the information recording medium, A decrease in the signal amount of the racking error signal can be suppressed. As a result, the dependency of the tracking error signal intensity on the shift of the objective lens becomes extremely small as compared with the related art, so that it is possible to provide an optical head device capable of realizing a stable servo operation.
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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EP01902732A EP1253588A4 (en) | 2000-02-04 | 2001-02-01 | OPTICAL HEAD |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2000-027452 | 2000-02-04 | ||
JP2000027452 | 2000-02-04 |
Publications (1)
Publication Number | Publication Date |
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WO2001057862A1 true WO2001057862A1 (fr) | 2001-08-09 |
Family
ID=18553021
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/JP2001/000725 WO2001057862A1 (fr) | 2000-02-04 | 2001-02-01 | Dispositif de tete optique |
Country Status (6)
Country | Link |
---|---|
US (1) | US20020181384A1 (ja) |
EP (1) | EP1253588A4 (ja) |
KR (1) | KR100470469B1 (ja) |
CN (1) | CN1213417C (ja) |
TW (1) | TW492000B (ja) |
WO (1) | WO2001057862A1 (ja) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007193894A (ja) * | 2006-01-19 | 2007-08-02 | Sony Corp | 光記録再生装置、光学ピックアップ及びトラッキングエラー信号検出方法 |
US7852732B2 (en) | 2007-02-20 | 2010-12-14 | Canon Kabushiki Kaisha | Lens apparatus |
JP5386553B2 (ja) * | 2011-07-15 | 2014-01-15 | シャープ株式会社 | 光ピックアップ装置 |
CN103076286B (zh) * | 2011-10-26 | 2015-06-24 | 联发科技股份有限公司 | 用于观察物体的光声显微镜系统及其方法 |
KR102180125B1 (ko) | 2019-03-11 | 2020-11-17 | 이상현 | 포장용 종이백 |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS61206925A (ja) * | 1985-03-08 | 1986-09-13 | Matsushita Electric Ind Co Ltd | 光学記録再生装置 |
JPH05314572A (ja) * | 1992-05-13 | 1993-11-26 | Ricoh Co Ltd | 光ピックアップ装置 |
JPH06168462A (ja) * | 1992-11-30 | 1994-06-14 | Sharp Corp | 光学ヘッド |
JP2000011403A (ja) * | 1998-06-29 | 2000-01-14 | Sony Corp | 光情報記録再生装置および光情報記録再生方法 |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS58190906A (ja) * | 1982-05-01 | 1983-11-08 | Sano Kiko Kk | ビ−ムスプリツタ− |
JPH0677351B2 (ja) * | 1986-11-15 | 1994-09-28 | ソニー株式会社 | 光学ピツクアツプ装置 |
GB2248989B (en) * | 1990-10-15 | 1995-05-24 | Applied Magnetics Corp | Focus sensing apparatus and method |
EP0601862A1 (en) * | 1992-12-09 | 1994-06-15 | Omron Corporation | An optical device formed of multiple film layers |
WO1995014299A1 (fr) * | 1993-11-19 | 1995-05-26 | Sony Corporation | Appareil de lecture optique |
JP3601219B2 (ja) * | 1996-11-13 | 2004-12-15 | 松下電器産業株式会社 | 光ピックアップ用の平行プリズム |
KR19990074812A (ko) * | 1998-03-14 | 1999-10-05 | 윤종용 | 호환형 광픽업장치 |
-
2001
- 2001-01-31 TW TW090101877A patent/TW492000B/zh not_active IP Right Cessation
- 2001-02-01 CN CNB018043666A patent/CN1213417C/zh not_active Expired - Fee Related
- 2001-02-01 EP EP01902732A patent/EP1253588A4/en not_active Withdrawn
- 2001-02-01 WO PCT/JP2001/000725 patent/WO2001057862A1/ja not_active Application Discontinuation
- 2001-02-01 KR KR10-2002-7001920A patent/KR100470469B1/ko not_active IP Right Cessation
- 2001-02-01 US US10/130,775 patent/US20020181384A1/en not_active Abandoned
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS61206925A (ja) * | 1985-03-08 | 1986-09-13 | Matsushita Electric Ind Co Ltd | 光学記録再生装置 |
JPH05314572A (ja) * | 1992-05-13 | 1993-11-26 | Ricoh Co Ltd | 光ピックアップ装置 |
JPH06168462A (ja) * | 1992-11-30 | 1994-06-14 | Sharp Corp | 光学ヘッド |
JP2000011403A (ja) * | 1998-06-29 | 2000-01-14 | Sony Corp | 光情報記録再生装置および光情報記録再生方法 |
Non-Patent Citations (1)
Title |
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See also references of EP1253588A4 * |
Also Published As
Publication number | Publication date |
---|---|
EP1253588A1 (en) | 2002-10-30 |
US20020181384A1 (en) | 2002-12-05 |
KR20020081201A (ko) | 2002-10-26 |
EP1253588A4 (en) | 2005-03-23 |
TW492000B (en) | 2002-06-21 |
CN1397069A (zh) | 2003-02-12 |
KR100470469B1 (ko) | 2005-02-05 |
CN1213417C (zh) | 2005-08-03 |
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