WO2012127831A1 - 光情報装置及びそのギャップ制御方法 - Google Patents
光情報装置及びそのギャップ制御方法 Download PDFInfo
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- WO2012127831A1 WO2012127831A1 PCT/JP2012/001844 JP2012001844W WO2012127831A1 WO 2012127831 A1 WO2012127831 A1 WO 2012127831A1 JP 2012001844 W JP2012001844 W JP 2012001844W WO 2012127831 A1 WO2012127831 A1 WO 2012127831A1
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- gap
- detection signal
- power
- recording medium
- 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
- G11B7/125—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
- G11B7/126—Circuits, methods or arrangements for laser control or stabilisation
- G11B7/1263—Power control during transducing, e.g. by monitoring
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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
- G11B7/0908—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 focusing only
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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
- G11B7/1387—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector using the near-field effect
-
- 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
- G11B2007/13727—Compound lenses, i.e. two or more lenses co-operating to perform a function, e.g. compound objective lens including a solid immersion lens, positive and negative lenses either bonded together or with adjustable spacing
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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
Definitions
- the present invention relates to an optical information apparatus for recording and / or reproducing information using an information recording medium and a gap control method thereof, for example, between an information layer of an optical disc or a cover layer for protecting the information layer and an optical system.
- the present invention relates to an apparatus and a gap control method thereof.
- an optical disc device using an optical head in which a condensing system that obtains a high numerical aperture by combining an objective lens and a solid immersion lens (hereinafter referred to as “SIL”) is proposed. Has been.
- SIL method a material having a high refractive index (about 1.8 to 2.0) is used for the protective layer of the SIL and the optical disk, and the gap length described above is kept constant. Gap control is performed. As a result, the gap length between the SIL and the protective layer of the optical disc becomes a minute value of about 25 nm, and the SIL is brought close to the protective layer of the optical disc. Information is recorded and reproduced by the evanescent light that is the emitted light from the SIL obtained in this way, and many documents related to this technology have already been published.
- Patent Document 1 describes an example of the above-described gap control.
- the numerical aperture of the condensing system including the SIL is 1.70 to 1.80, which is approximately twice the numerical aperture of 0.85 of the Blu-ray (hereinafter referred to as “BD”) system. It can be.
- the laser wavelengths are the same, the spot size of the light beam formed on the surface of the information layer of the optical disk is approximately halved. Therefore, the recording capacity per unit area, that is, the recording density is 4 Can be doubled.
- FIG. 8 is a schematic diagram showing the configuration of a conventional optical disc apparatus equipped with an SIL for explaining the gap control described above
- FIG. 9 is an enlarged view of a portion P indicated by a circle (broken line) in FIG. FIG.
- reference numeral 101 denotes an optical disk
- 102 denotes an SIL
- 103 denotes an objective lens
- the SIL 102 and the objective lens 103 are integrally connected by a fixture 104.
- GL indicates the gap length between the optical disc 101 and the SIL 102
- 107 indicates a gap control actuator.
- the light emitted from the laser 114 serving as the light source is converted into parallel light by the collimator lens 111, and becomes a light beam (bound) 120 through the polarization beam splitter 109.
- the light beam 120 is applied to the optical disc 101 via the ⁇ / 4 plate 112, the objective lens 103, and the SIL 102.
- the numerical aperture of the condensing system including the SIL 102 is as large as 1.70 to 1.80, most of the light beam 120 is reflected by the flat surface 115 of the SIL 102 and returned to the light beam 121. As shown in FIG. 9, the remaining light becomes evanescent light 116 and reaches the recording / reproducing surface of the optical disc 101.
- the light beam 121 reflected by the flat surface 115 of the SIL 102 is again incident on the polarization beam splitter 109 via the ⁇ / 4 plate 112, and is incident on the detector 110 as a gap detector by the action of the polarization beam splitter 109. .
- the detector 110 outputs a gap detection signal GD, and the gap control circuit 113 appropriately processes the gap detection signal GD to generate a gap control signal GC, and drives the gap control actuator 107. In this way, gap control is established.
- the purpose of providing the ⁇ / 4 plate 112 is that the return light 121 to the laser 114 can be blocked by disposing the polarization beam splitter 109 between the ⁇ / 4 plate 112 and the laser 114.
- FIG. 10 shows the relationship between the gap length GL and the amount of light reflected by the flat surface 115 of the SIL 102 when the effective refractive index of the SIL 102 shown in FIG. 8 is 2.1 and the reflectance of the optical disc 101 is 0.1.
- the amount of reflected light on the vertical axis is a value normalized with the amount of reflected light when the gap length GL is infinite
- the gap length on the horizontal axis is a value normalized with the wavelength of the laser 114.
- the gap length GL value 0.05 shown on the horizontal axis of FIG. 10 indicates a gap length of 20 nm as an absolute value.
- the incident power to the detector 110 shown in FIG. Will function as a gap detector.
- the gap detection is reflected light amount from the flat surface 115 of the SIL 102 that varies depending on the gap length GL, as shown in FIG. Based on the characteristics of
- the variation in the amount of reflected light from the flat surface 115 of the SIL 102 varies not only due to the variation in the gap length GL but also due to the variation in the power of the light beam 120 emitted from the laser 114 in FIG.
- the power fluctuation of the light beam 120 is regarded as a gap fluctuation by the above-described function of the gap detector, even though there is no actual gap fluctuation.
- the stability of the gap control is significantly lacking because it is performed based on fluctuations.
- laser power control is performed on the laser 114 in order to suppress fluctuations in the power of the light beam 120 emitted from the laser 114.
- FIG. 11 is a diagram showing a configuration of a conventional signal recording apparatus that performs gap control including laser power control.
- the signal recording apparatus shown in FIG. 11 includes an information source 201, a recording signal generator 202, an acousto-optic element (AOM) 203, and a laser element 204 as a light source that emits a recording laser beam LB1.
- AOM acousto-optic element
- Electro-Optical Modulator (EOM) 205 Analyzer 206, Beam Splitter (BS) 207, First Photodetector (PD1) 208a, Second Photodetector (PD2) 208b, Auto Power A controller (APC: Auto Power Controller) 209, a first mirror 210a, a second mirror 210b, a third mirror 210c, a first condenser lens 211a, a second condenser lens 211b, Kori And Tarenzu 212, a polarization beam splitter (PBS) 213, includes a lambda / 4 plate 214, an optical head 216 made up of a second group lens of the condenser lens 216a and SIL216b attached to the piezoelectric element 215.
- EOM Electro-Optical Modulator
- BS Beam Splitter
- PD1 First Photodetector
- PD2 Second Photodetector
- a controller Auto Power A controller
- PBS polarization beam splitter
- the signal recording apparatus shown in FIG. 11 limits the frequency band of the light quantity of the return light LB2 from the optical head 216 and outputs the return light quantity after the band restriction, and the band restriction circuit 220.
- a gap control device 221 is provided that outputs a gap control voltage in accordance with the output band-limited return light amount and controls the distance between the optical head 216 and the glass master 217 to be constant.
- the recording laser beam LB1 incident on the first photodetector 208a is converted into an electric signal, and the output voltage is input to the automatic power control apparatus (APC) 209.
- the difference between the output voltage and the reference voltage is fed back to the applied voltage of the EOM 205, and the laser power of the recording laser beam LB1 output from the laser element 204 is controlled to be constant.
- An object of the present invention is to provide an optical information apparatus capable of reducing unnecessary fluctuations not caused by gap fluctuations and stably performing gap control.
- An optical information device is an optical information device that records and / or reproduces information using an information recording medium, and uses the light source that emits light and the light from the light source to transmit the information.
- An optical system that forms a beam spot of a predetermined size on a recording medium, a power detection unit that detects an output power of the light source to generate a power detection signal, and an output of the light source using the power detection signal
- a power control unit that controls power
- a gap detection unit that detects a gap length between the information recording medium and the optical system to create a gap detection signal; and the information recording medium using the gap detection signal.
- a gap control unit that controls a gap length between the optical system and the power control unit, wherein the power control unit has a gain intersection point that is larger than a gain intersection point of the gap control unit.
- An optical information device is an optical information device that records and / or reproduces information using an information recording medium, and uses a light source that emits light and light from the light source, An optical system that forms a beam spot of a predetermined size on an information recording medium, a power detection unit that detects an emission power of the light source to create a power detection signal, and the power detection signal A power control unit that controls output power; a gap detection unit that detects a gap length between the information recording medium and the optical system to create a gap detection signal; and a gain of the power control unit from the gap detection signal A correction unit that generates a correction gap detection signal from which a fluctuation component equal to or greater than the intersection is removed, and a gap length between the information recording medium and the optical system are controlled using the correction gap detection signal. That and a gap control unit.
- FIG. 1 is a schematic diagram showing a configuration of an optical disc device according to Embodiment 1 of the present invention. It is a figure which shows the control characteristic of the comparative example which made the gain intersection of laser power control 1kHz, and the gain intersection of gap control 10kHz.
- FIG. 2 is a circuit diagram showing a configuration of an example of a laser driving circuit shown in FIG. 1. It is a figure which shows the relationship between the gap length and the amount of reflected light in the area
- optical disc apparatus which is an example of an optical information apparatus.
- the optical information apparatus to which the present invention is applied is not particularly limited to the following optical disk apparatus, and can be similarly applied to various optical information apparatuses using an information recording medium having a shape other than the disk shape.
- FIG. 1 is a schematic diagram showing a configuration of an optical disc apparatus according to Embodiment 1 of the present invention.
- the optical disk apparatus shown in FIG. 1 includes an SIL 2, an objective lens 3, a fixture 4 that connects the SIL 2 and the objective lens 3, a gap control actuator 7, a polarization beam splitter 9, a detector 10, a collimator lens 11, and a ⁇ / 4 plate 12.
- the laser power control circuit 27 includes a laser drive circuit 27 a that drives the laser 14.
- the power supply 28 supplies power to each circuit in the apparatus such as the laser 14, the detector 26, and the laser power control circuit 27, and for example, a switching power supply can be used. Further, as the gap control actuator 7, actuators of various systems such as a moving coil system can be used. Note that the gap length GL in the figure indicates the distance between the surface of the optical disc 1 which is an example of the information recording medium and the flat surface EL of the SIL 2.
- the laser 14 corresponds to an example of a light source
- the SIL 2 and the objective lens 3 correspond to an example of an optical system
- the detector 26 corresponds to an example of a power detection unit
- the laser power control circuit 27 performs power control.
- the detector 10 corresponds to an example of a gap detector
- the gap control circuit 15 corresponds to an example of a gap controller
- the power source 28 corresponds to an example of a power source.
- the laser 14 emits laser light, and the light emitted from the laser 14 enters the beam splitter 25.
- the beam splitter 25 splits the light beam emitted from the laser 14, a part of the split light beam LD is incident on the detector 26, and the remaining most of the light beam is incident on the collimating lens 11.
- the detector 26 functions as a power detection unit that detects the emission power of the laser 14 and creates a laser power detection signal PD, photoelectrically converts the divided light beam LD, and converts the laser power detection signal PD into a laser power control circuit 27. Output to.
- the laser power control circuit 27 appropriately processes the laser power detection signal PD, and outputs a laser power drive signal (drive current) DS to the laser 14 to drive the laser 14. As a result, laser power control for controlling the emission power of the laser 14 is established using the laser power detection signal PD.
- the collimating lens 11 converts the light beam incident from the beam splitter 25 into parallel light, and the parallel light passes through the polarization beam splitter 9 and the ⁇ / 4 plate 12 to become a light beam (bound) LF.
- the light beam LF passes through the objective lens 3 and the SIL 2 and is irradiated onto the optical disc 1.
- a condensing unit that condenses the light emitted from the laser 14 from the SIL 2 and the objective lens 3 to form a beam spot having a predetermined size on the optical disc 1 is configured.
- an optical system for forming a beam spot having a predetermined size on the optical disc 1 using the light emitted from the laser 14 is configured.
- the numerical aperture of the condensing unit including SIL2 is as large as 1.70 to 1.80, most of the light beam LF is reflected by the flat surface FP of SIL2 and returned to the light beam (return). ) LB, and the remaining light of the light beam LF reaches the recording / reproducing surface (not shown) of the optical disc 1 as evanescent light EL.
- the light beam LB reflected by the flat surface FP of the SIL 2 is again incident on the polarization beam splitter 9 via the ⁇ / 4 plate 12, reflected by the polarization beam splitter 9, and incident on the detector 10.
- the detector 10 functions as a gap detection unit that detects a gap length between the optical disc 1 and the optical system (flat surface FP of the SIL 2) to generate a gap detection signal GD, and photoelectrically converts the incident light beam to generate a gap.
- a detection signal GD is generated and output to the gap control circuit 15.
- the gap control circuit 15 appropriately processes the gap detection signal GD, generates a gap control signal GC, and outputs it to the gap control actuator 7.
- the gap control actuator 7 is driven according to the gap control signal GC.
- gap control for controlling the gap length between the optical disc 1 and the optical system (flat surface FP of the SIL 2) is established using the gap detection signal GD.
- the inventors of the present application diligently studied the laser power fluctuation that becomes a problem when performing laser power control, and relatively high frequency components other than the relatively low frequency components caused by the temperature characteristics of the laser 14. It was found that the influence of the switching noise of the power supply 28 is dominant as the laser power fluctuation having Hereinafter, this point will be described in detail.
- the gain crossover frequency of laser power control is set to about 1 kHz, DC
- the laser power control in the nearby low frequency region also has a gain of about 80 dB, and a sufficient fluctuation suppressing effect can be obtained for the laser power fluctuation in the vicinity of the frequency. Therefore, fluctuations in the amount of reflected light that are not caused by gap fluctuations can be sufficiently suppressed, and thus do not cause instability in gap control.
- the control band of the gap control that is, the gain intersection frequency, realizes sufficient follow-up ability even at high speed rotation with respect to minute irregularities on the surface of the optical disc 1. Therefore, it is desirable that the frequency be about 10 kHz.
- FIG. 2 is a diagram showing control characteristics when the laser power control gain crossing point is 1 kHz and the gap control gain crossing point is 10 kHz, which was examined by the inventors of the present application as a comparative example.
- LC indicates the control characteristic of laser power control
- G1 indicates the gain intersection 1 kHz
- GC indicates the control characteristic of gap control
- G2 indicates the gain intersection 10 kHz.
- the laser power control characteristics as shown in FIG. 2 can be appropriately determined in consideration of the characteristics of the detector 26, the laser power control circuit 27, and the laser 14 shown in FIG. Can be appropriately determined in consideration of the characteristics of the detector 10, the gap control circuit 15, the gap control actuator 7, and the gap-total reflected light quantity characteristics as shown in FIG.
- the frequency component is higher than the gain intersection frequency G1 (1 kHz) of the laser power control characteristic and lower than the gain intersection frequency G2 (10 kHz) of the gap control characteristic, That is, consider the case of being in the frequency domain FA shown in FIG.
- the gain intersection frequency G1 of the laser power control characteristic is 1 kHz
- the effect of suppressing the laser power fluctuation having the frequency component in the frequency domain FA cannot be obtained by the laser power control.
- the laser power fluctuation having the frequency component in the frequency domain FA becomes the laser power fluctuation within the gap control band, and the laser power fluctuation becomes the fluctuation of the reflected light amount.
- a change in the amount of reflected light that is not caused by a change in the gap is regarded as a change in the gap, and the gap control becomes unstable.
- FIG. 3 is a circuit diagram showing a configuration of an example of the laser drive circuit 27a shown in FIG.
- the laser drive circuit shown in FIG. 3 includes a resistor R1 having a predetermined resistance value R and a transistor Q1. One end of the resistor R1 is connected to the power supply line PL having the power supply voltage V supplied from the power supply 28, and the other end is connected to the emitter of the transistor Q1.
- the base of the transistor Q1 receives a laser control signal CS generated by appropriately processing the laser power detection signal PD in the laser power control circuit 27, the collector of the transistor Q1 is connected to the laser 14, and the transistor Q1 As the laser power drive signal DS, the laser 14 is driven by outputting a drive current DI corresponding to the laser control signal CS.
- the current Ir in the equation (1) that is, the driving current DI of the laser 14 is the variation of the power supply voltage V.
- the laser power fluctuates.
- the variation is due to switching noise, and ⁇ V / V, which is the ratio between the power supply voltage V and the variation ⁇ V due to the switching noise, It is about 0.8%, and the switching frequency is several kHz.
- the frequency component of ⁇ V exists in the frequency region FA of FIG. 2, and as described above, the effect of suppressing the laser power fluctuation caused by ⁇ V cannot be obtained by laser power control.
- the fluctuation amount ⁇ V of the power supply voltage V becomes a laser power fluctuation within the gap control band, and the reflected light quantity incident on the detector 10 also fluctuates due to the power fluctuation.
- the fluctuation ⁇ Ir of the drive current DI of the laser 14 due to the fluctuation ⁇ V due to switching noise is expressed by the following equation (2) from the equation (1).
- the output power Pw of the laser 14 when the drive current-output power sensitivity of the laser 14 is 1.5 watts / ampere and the threshold current of the laser 14 is 0.13 amperes is expressed by the following equation (3). Is done. Note that Ir in the equation (3) is the drive current DI of the laser 14 expressed by the equation (1).
- Equation (3) Pw variation ⁇ Pw due to Ir variation ⁇ Ir is expressed by the following Equation (4), and ⁇ Pw is 6 ⁇ 10 ⁇ 5 Watt, and Pw is 0.0035 Watt.
- the variation ratio ⁇ Pw / Pw of the output power of the laser 14 is approximately 0.017 (approximately 1.7%).
- the value of 0.0035 watts of Pw described above is a value studied by the inventors of the present application, and in the optical disk apparatus having the control characteristics as shown in FIG. 2, the light beam LF emitted from the laser 14 or In order to obtain an appropriate gap detection signal GD for gap control in consideration of transmission efficiency of optical elements such as the polarization beam splitter 9 and the ⁇ / 4 plate 12 through which the light beam LB reflected by the flat surface FP of SIL2 passes.
- the value of ⁇ Pw / Pw which is the fluctuation ratio of the emission power of the laser 14 described above, is approximately 0.017 (approximately 1.7%)
- the value of ⁇ Pw / Pw itself is the value of ⁇ P in equation (6). Therefore, from equation (6), the fluctuation amount ⁇ G of the gap G is estimated to be approximately 0.53%.
- the amount of fluctuation ⁇ P (approximately 1.7%) of the reflected light amount is caused by the fluctuation ⁇ V of the power supply voltage V of the power supply line PL shown in FIG. It is not due to actual gap fluctuations. Further, as described above, since the frequency component of the variation ⁇ V of the power supply voltage V is in the frequency region FA shown in FIG. 2, the frequency component of the variation of the reflected light amount of about 1.7% is also in the frequency region FA. There will be.
- the fluctuation amount is equal to approximately 0.53% which is the value of ⁇ G which is the fluctuation amount of the gap G obtained by the above-described equation (6).
- the accuracy required for the gap control is as follows. That is, in order to properly irradiate the information surface of the optical disc 1 with the energy of the light beam at the time of recording or to maintain the constancy of the reproduction signal quality at the time of reproduction, it is allowed when the gap length is set to 25 nm.
- the gap fluctuation amount is about 0.1 nm, which is 0.4% with respect to the target value of 25 nm gap control.
- the gap variation of about 0.53% described above exceeds the allowable value of 0.4%, which is not a preferable situation for recording / reproducing of an optical disk by the SIL method.
- the switching frequency of the power supply 28 (that is, the frequency of fluctuation of the power supply voltage due to switching noise) is made larger than the gain intersection frequency G2 of the control characteristic GC of the gap control shown in FIG.
- the frequency component of the light amount fluctuation is also out of the control band of the gap control.
- the gap control as described above the gap is not considered to be “fluctuated” even though the gap is “not changed”, and works in a direction away from the target value of the gap control. There is no.
- the fluctuation of the power supply voltage is the switching noise of the power supply 28 as a factor that makes the gap control described above unstable.
- the fluctuation of the power supply voltage is not only the switching noise but also the optical disc apparatus. 2 may be caused by the influence of a current flowing in a circuit (not shown) other than the gap control circuit constituting the circuit, and there is a possibility that the frequency component of the fluctuation of the power supply voltage is in the frequency domain FA shown in FIG. I also understood that.
- FIG. 5 is a diagram showing control characteristics of laser power control and gap control of the optical disc apparatus shown in FIG.
- the control characteristic GC of the gap control is the control characteristic of the gap control circuit 15, and in this embodiment, the control band of the gap control, that is, the gain intersection frequency G2 of the gap control circuit 15 is With respect to minute irregularities on the surface of the optical disc 1, it is set to 10 kHz which is a desirable gain intersection frequency for realizing sufficient follow-up capability even at high speed rotation.
- the laser power control characteristic LU is a control characteristic of the laser power control circuit 27.
- the laser power control band that is, the gain intersection frequency G3 of the laser power control circuit 27 is 100 kHz. Is set to Thus, in the present embodiment, the gain intersection frequency G3 of the laser power control circuit 27 is set to 100 kHz, and is 10 times the gain intersection frequency G2 (10 kHz) of the gap control circuit 15.
- the gap control and the laser power control have the characteristics as shown in FIG. 2, the fluctuation of the power supply voltage V of the power supply 28, which becomes a fluctuation factor of the laser power, can be suppressed.
- the switching frequency when the power supply 28 is a switching power supply is several kHz
- the frequency component of the switching noise ⁇ V is several kHz
- the frequency is the gain of the laser power control characteristic LU in the present embodiment. It is sufficiently lower than the intersection frequency G2 (100 kHz). That is, the laser power control circuit 27 has a gain intersection higher than the frequency of noise from the power supply 28.
- the laser power control gain is 20 dB to 40 dB, so that the power fluctuation due to the switching noise ⁇ V is approximately 1.7%. Even so, the power fluctuation can be suppressed from about 0.17% to about 0.017%, and the fluctuation of the reflected light amount can be reduced from about 0.17% to about 0.017%.
- the variation ⁇ P in the amount of reflected light can be reduced from about 0.17% to about 0.017%, and thus corresponds to the variation ⁇ P in the amount of reflected light from the above equation (6).
- the gap length variation ⁇ G is obtained, the gap length variation ⁇ G is changed from approximately 0.05% to approximately 0.005%, and the gap length variation can be suppressed to 1/10.
- This variation in the amount of reflected light (approximately 0.05% to approximately 0.005%) is caused by the variation ⁇ V of the power supply voltage V of the power supply line PL shown in FIG. Instead, since the frequency component of the variation ⁇ V of the power supply voltage V is in the frequency domain FA shown in FIG. 5, the frequency component of the fluctuation of the reflected light amount of about 0.05% to about 0.005% is also the frequency domain FA. Will be in.
- the gap control circuit 15 says that the gap is “fluctuated” even though the gap is “not changed”.
- the gap control has an irregular behavior that works in a direction away from the target value.
- the gap fluctuation amount generated by the irregular behavior is approximately 0.005% or less with respect to the target value.
- the gap variation allowed for the energy of the optical beam at the time of recording to be appropriately applied to the information surface of the optical disc 1 or to maintain the constancy of the reproduction signal quality at the time of reproduction is 0.4%.
- the gap fluctuation amount of about 0.005% or less is a sufficiently small value, and in the present embodiment, appropriate irradiation of the information surface of the optical disk 1 with a light beam at the time of recording, or It is possible to sufficiently achieve the purpose of ensuring the constancy of reproduction signal quality during reproduction.
- the control band (gain intersection frequency) of the laser power control circuit 27 and the control band (gain intersection frequency) of the gap control circuit 15 are distinct.
- the magnitude relationship that is, the magnitude relationship in which the former is 10 times the latter
- the total reflected light amount fluctuation caused by the power fluctuation within the control band of the gap control that is, the frequency band below the gain intersection frequency
- the control band (gain intersection frequency) of the laser power control circuit 27, which is a component of the optical disk apparatus, is set to 10 times the control band (gain intersection frequency) of the gap control circuit 15, but this example There are no particular limitations, and various modifications are possible. For example, it is at least a component of an optical disk device to suppress fluctuations in the amount of reflected light caused by power fluctuations within the control band of the gap control (that is, the frequency band below the gain intersection frequency) and to suppress unstable operation of the gap control.
- the control band (gain intersection frequency) of the laser power control circuit 27 may be set to be equal to or greater than the control band (gain intersection frequency) of the gap control circuit 15. Further, the former may be set to be larger than 10 times the latter, and in this case, it is clear that the effect of suppressing the unstable operation of the gap control can be further increased. This is the same for the other embodiments.
- the setting of the size of the control band (gain intersection frequency) of the laser power control circuit 27 with respect to the control band (gain intersection frequency) of the gap control circuit 15 which is a component of the optical disk apparatus of the present embodiment is It is desirable to determine in consideration of the frequency component and the magnitude of the fluctuation factor of the laser power generated in the optical disc apparatus.
- the present embodiment is an optical disc apparatus that performs recording / reproduction (recording / reproduction by a plasmon method) on an optical disc using plasmon light generated by irradiating a metal chip with a light beam.
- FIG. 6 is a schematic view mainly showing the light condensing unit of the optical disc apparatus according to Embodiment 2 of the present invention.
- the optical disc apparatus according to the present embodiment includes a SIL 2 a, a metal chip 2 b, an objective lens 3, and a fixture 4 that connects the SIL 2 a and the objective lens 3.
- the optical disc 1a includes a plurality of fine particles 1b, and unlike the optical disc 1 shown in FIG. 2, fine particles (several nm to several tens of nm) 1b are formed on the surface of the optical disc 1a.
- the plasmon system used in the present embodiment generates plasmon light PB by irradiating the metal chip 2b formed integrally with the SIL 2a with the light beam narrowed down by the objective lens 3 and the SIL 2a.
- recording marks are formed on the fine particles 1b on the surface of the optical disc 1a.
- an optical system is formed that forms a beam spot having a predetermined size on the optical disc 1a by using the light emitted from the laser 14 from the metal chip 2b, the SIL 2a, and the objective lens 3.
- the constituent elements other than the constituent elements described above are the constituent elements shown in FIG. 1 that are the structural diagram of the optical disc apparatus of the first embodiment, such as the gap control circuit 15, the laser power control circuit 27, and the like. Since it is the same, the description is omitted.
- the gap length GL is a gap length between the optical disc 1a and the SIL 2a, and the size thereof is a minute value of about 25 nm. Even in the plasmon system used in the present embodiment, a request for the size is required. Is the same as that for the SIL method described in the first embodiment.
- gap control is indispensable, and the relationship between the control band for gap control and the control band for laser power control in this embodiment is described in the first embodiment. This is the same as FIG.
- control characteristic GC of the gap control is the control characteristic of the gap control circuit 15, and the control band of the gap control, that is, the gain intersection frequency of the gap control circuit 15 G2 is set to 10 kHz, which is a desirable gain crossover frequency for realizing sufficient follow-up capability even at high speed rotation with respect to minute irregularities on the surface of the optical disc 1a.
- the control characteristic LU of laser power control is the control characteristic of the laser power control circuit 27, and the control band of laser power control, that is, the gain intersection frequency G3 of the laser power control circuit 27 is 100 kHz. Is set to Thus, also in this embodiment, the gain intersection frequency G3 of the laser power control circuit 27 is set to 100 kHz, and is set to 10 times the gain intersection frequency G2 (10 kHz) of the gap control circuit 15.
- the gap control and the laser power control have the characteristics as shown in FIG. 2, the fluctuation of the power supply voltage V of the power supply 28 that causes the fluctuation of the laser power is suppressed.
- the switching frequency when the power supply 28 is a switching power supply is several kHz
- the frequency component of the switching noise ⁇ V is several kHz
- the frequency is the gain of the laser power control characteristic LU in the present embodiment. It is sufficiently lower than the intersection frequency G2 (100 kHz). That is, the laser power control circuit 27 has a gain intersection higher than the frequency of noise from the power supply 28.
- the laser power control gain is 20 dB to 40 dB, so that the power fluctuation due to the switching noise ⁇ V is approximately 1.7%. Even so, the power fluctuation can be suppressed from about 0.17% to about 0.017%, and the fluctuation of the reflected light amount can be reduced from about 0.17% to about 0.017%.
- the variation ⁇ P in the amount of reflected light can be reduced from about 0.17% to about 0.017%, and therefore corresponds to the variation ⁇ P in the amount of reflected light from the above equation (6).
- the gap length variation ⁇ G is approximately 0.05% to approximately 0.005%, and the gap length variation can be suppressed to 1/10.
- This variation in the amount of reflected light (approximately 0.05% to approximately 0.005%) is caused by the variation ⁇ V of the power supply voltage V of the power supply line PL shown in FIG. Instead, since the frequency component of the variation ⁇ V of the power supply voltage V is in the frequency domain FA shown in FIG. 5, the frequency component of the fluctuation of the reflected light amount of about 0.05% to about 0.005% is also the frequency domain FA. Will be in.
- the gap control circuit 15 says that the gap is “fluctuated” even though the gap is “not changed”.
- the gap control has an irregular behavior that works in a direction away from the target value.
- the gap fluctuation amount generated by the irregular behavior is approximately 0.005% or less with respect to the target value.
- the gap variation allowed for the energy of the optical beam at the time of recording to be appropriately applied to the information surface of the optical disc 1 or to maintain the constancy of the reproduction signal quality at the time of reproduction is 0.4%.
- the gap fluctuation amount of about 0.005% or less is a sufficiently small value, and in this embodiment as well, appropriate irradiation or reproduction of the information surface of the optical disk at the time of recording is performed. It is possible to sufficiently achieve the purpose of ensuring the constancy of the reproduced signal quality at the time.
- the control band (gain intersection frequency) of the laser power control circuit 27, which is a component thereof, and the control band of the gap control circuit 15 are the same.
- a clear magnitude relationship in (gain intersection frequency) that is, a magnitude relationship in which the former is 10 times the latter
- power fluctuation within the control band of the gap control that is, the frequency band below the gain intersection frequency
- the resulting total reflected light amount fluctuation can be suppressed to an extremely small value, and as a result, stable operation of the gap control can be ensured.
- the setting of the size of the control band (gain intersection frequency) of the laser power control circuit 27 with respect to the control band (gain intersection frequency) of the gap control circuit 15 which is a component of the optical disk apparatus of the present embodiment It is desirable to determine in consideration of the frequency component and the magnitude of the fluctuation factor of the laser power generated among them.
- an optical system that performs recording / reproduction on an optical disk using plasmon light generated by irradiating a metal chip with a light beam has been described as an example.
- the present invention is not limited to the above examples.
- the present invention can be applied to an optical information apparatus that records and / or reproduces information on an information recording medium using light by various methods.
- an optical system that generates plasmon light by irradiating a light beam onto a scatterer (for example, a metal chip) formed on a predetermined substrate without using SIL may be used.
- optical disk devices that use near-field light such as evanescent light or plasmon light for gap control and / or tracking control, and information recording media are heated using near-field light, and information is obtained by a magnetic field generated by magnetic poles at the same time.
- the present invention can also be applied to an optical disc apparatus or the like provided with an optically assisted magnetic recording head or the like for recording on a recording medium, and similar effects can be obtained.
- FIG. 7 is a schematic diagram showing the configuration of the optical disc apparatus according to Embodiment 3 of the present invention.
- the optical disk apparatus shown in FIG. 7 includes an SIL 2, an objective lens 3, a fixture 4 that connects the SIL 2 and the objective lens 3, a gap control actuator 7, a polarization beam splitter 9, a detector 10, a collimator lens 11, and a ⁇ / 4 plate 12.
- the detector 26 corresponds to an example of a power detection unit
- the laser power control circuit 27 corresponds to an example of a power control unit
- the detector 10 corresponds to an example of a gap detection unit
- the gap control circuit 15 includes Corresponding to an example of the gap control unit, the filter 35 and the adder 36 correspond to an example of the correction unit, the filter 35 corresponds to an example of the filter unit, the adder 36 corresponds to an example of the fluctuation component removal unit, and others This point is the same as in the first embodiment.
- a feature of the present embodiment is that, when a power fluctuation that cannot be suppressed by the laser power control system occurs, as a countermeasure to an unstable operation of the gap control due to the fluctuation of the reflected light amount not caused by the actual gap fluctuation, This is because attention is paid to the offset between the power fluctuation and the fluctuation in the amount of reflected light.
- the optical disk device shown in FIG. 7 is different from the disk device shown in FIG. 1 in the following points.
- the detector 26 inputs the laser power detection signal PD to the laser power control circuit 27 and also inputs it to the filter 35.
- the filter 35 extracts a power fluctuation component that cannot be suppressed by the laser power control system from the laser power detection signal PD, for example, a component in the frequency band FA shown in FIG. 2, and adjusts the level and phase of this component.
- the filter 35 inputs to the adder 36 a corrected laser power detection signal CP in which the phase of the extracted component is adjusted to an opposite phase so that the adder 36 can cancel it.
- the adder 36 adds the corrected laser power detection signal CP to the gap detection signal GD at a predetermined ratio, thereby generating a power fluctuation component that cannot be suppressed by the laser power control system (laser power control circuit 27b) from the gap detection signal GD.
- the removed signal is input to the gap control circuit 15 as a corrected gap detection signal GA, and the gap control circuit 15 performs gap control using the corrected gap detection signal GA.
- the laser power control circuit 27b has the control characteristic LC of laser power control shown in FIG. 2, and the gain intersection frequency G3 of the laser power control circuit 27b is set to 1 kHz.
- the laser power control circuit 27b having a gain crossover frequency of 100 kHz cannot suppress power fluctuations higher than the gain crossover frequency G3 (1 kHz), but as described above, the power that cannot be suppressed by the laser power control circuit 27b.
- the gap control circuit 15 performs gap control using the corrected gap detection signal GD from which the fluctuation component has been removed from the gap detection signal GD, it is not affected by power fluctuations that cannot be suppressed by the laser power control circuit 27b. , Gap control can be performed.
- the filter 35 shown in FIG. 7 is used, and the filter 35 appropriately adjusts the level and phase of the power fluctuation component included in the laser power detection signal PD that cannot be suppressed by the laser power control system. It is adjusted. Thereafter, the adder 36 generates the corrected gap detection signal GA by adding the corrected laser power detection signal CP to the gap detection signal GD so that the power fluctuation component that cannot be suppressed by the laser power control system is removed.
- the corrected gap detection signal GA from which the power fluctuation component that cannot be suppressed by the power control system is removed is input from the adder 36 to the gap control circuit 15.
- the power fluctuation that cannot be suppressed by the laser power control system and the reflected light quantity fluctuation are canceled out, and the gap detection in which the influence of the power fluctuation is removed from the gap detection signal GD. Since the signal is input to the gap control circuit 15 as the correction gap detection signal GA of the adder 36, stable operation of the gap control that is not affected by power fluctuations that cannot be suppressed by the laser power control system. Can be secured.
- the corrected gap detection signal GA from which the influence of the power fluctuation is removed from the gap detection signal GD is generated using the filter 35 and the adder 36.
- the present invention is not particularly limited to this example. Can be changed.
- the same effect can be obtained by using a band-pass filter (or high-pass filter) and a subtracter instead of the filter 35 and the adder 36.
- the band-pass filter extracts from the laser power detection signal PD a power fluctuation component that cannot be suppressed by the laser power control system, for example, a fluctuation component greater than or equal to the gain intersection of the laser power control circuit 27b.
- the corrected laser power detection signal is output to the subtractor, and the subtractor subtracts the corrected laser power detection signal from the gap detection signal GD at a predetermined ratio, thereby changing the fluctuation component equal to or higher than the gain intersection of the laser power control circuit 27b to the gap.
- a correction gap detection signal removed from the detection signal may be created, and the gap control circuit 15 may perform gap control using the correction gap detection signal.
- the bandpass filter and the subtractor correction unit correspond to an example
- the bandpass filter corresponds to an example of the filter unit
- the subtractor corresponds to an example of the fluctuation component removal unit.
- the control characteristics of the laser power control circuit are not particularly limited to the above example, and various changes can be made.
- a laser power control circuit 27 having a gain intersection frequency of 100 kHz shown in FIG. 1 may be used instead of the laser power control circuit 27b.
- the filter 35 extracts the fluctuation component of the emission power of the laser 14 from the laser power detection signal PD, and the adder 36 removes the fluctuation component extracted by the filter 35 from the gap detection signal GD.
- a corrected gap detection signal GA from which fluctuation components that are not caused by fluctuations in the gap between the optical disk 1 and the SIL 2 are removed is created, and the gap control circuit 15 uses the correction gap detection signal GA to detect the optical disk 1 and the SIL 2. You may make it control the gap length between. In this case, more stable gap control can be realized.
- an optical information device is an optical information device that records and / or reproduces information using an information recording medium, and uses a light source that emits light and light from the light source.
- An optical system that forms a beam spot of a predetermined size on the information recording medium, a power detection unit that detects an emission power of the light source to create a power detection signal, and the power detection signal, Using a power control unit that controls the emission power of a light source, a gap detection unit that detects a gap length between the information recording medium and the optical system and creates a gap detection signal, and the gap detection signal, A gap control unit that controls a gap length between the information recording medium and the optical system, and the power control unit has a gain intersection that is larger than a gain intersection of the gap control unit.
- the power control unit since the power control unit has a gain intersection greater than the gain intersection of the gap control unit, the power control unit can suppress unnecessary light amount fluctuations in the control band of the gap control unit. . Accordingly, since fluctuations in the amount of light that are not caused by gap fluctuations can be reduced and gap fluctuations can be detected accurately, gap control can be stably performed based on these accurate gap fluctuations. As a result, even if a total reflected light amount fluctuation not caused by the gap fluctuation, that is, the laser power fluctuation occurs, the unstable operation of the gap control can be suppressed, so that an unnecessary fluctuation not caused by the gap fluctuation is reduced, Gap control can be performed stably.
- the power control unit has a gain intersection that is 10 times or more the gain intersection of the gap control unit.
- the total reflected light amount fluctuation caused by power fluctuation in the control band of the gap control that is, in the frequency band below the gain intersection frequency of the gap control unit can be suppressed to an extremely small value. It is possible to reliably ensure the operation.
- the apparatus further includes a power source that supplies power for driving the light source, and the power control unit has a gain intersection higher than a frequency of noise from the power source.
- the power control unit can suppress power fluctuations caused by noise from the power supply, it is possible to accurately detect gap fluctuations by eliminating the influence of unnecessary power fluctuations due to noise from the power supply.
- the gap control can be stably performed using this accurate gap variation.
- the correction unit further includes a correction unit that generates a correction gap detection signal by removing a fluctuation component that is not caused by a gap fluctuation between the information recording medium and the optical system from the gap detection signal, and the gap control unit includes the correction gap. It is preferable to control a gap length between the information recording medium and the optical system using a detection signal.
- a corrected gap detection signal is created by removing a fluctuation component that is not caused by a gap change between the information recording medium and the optical system, and the correction gap detection signal is used between the information recording medium and the optical system. Therefore, a stable operation of the gap control can be ensured without being affected by unnecessary fluctuations not caused by gap fluctuations.
- the correction unit extracts a fluctuation component of the emission power of the light source from the power detection signal, and removes the fluctuation component extracted by the filter unit from the gap detection signal, thereby correcting the correction gap detection signal. It is preferable to include a fluctuation component removing unit that creates
- the fluctuation component of the emission power of the light source is extracted from the power detection signal, and the extracted fluctuation component is removed from the gap detection signal, so that the gap is not affected by the light amount fluctuation not caused by the gap fluctuation. Variations can be detected accurately.
- An optical information device is an optical information device that records and / or reproduces information using an information recording medium, and uses a light source that emits light and light from the light source, An optical system that forms a beam spot of a predetermined size on the information recording medium, a power detection unit that detects an output power of the light source to create a power detection signal, and the light source using the power detection signal
- a power control unit that controls the output power of the power source, a gap detection unit that detects a gap length between the information recording medium and the optical system, and creates a gap detection signal; and
- a correction unit that generates a correction gap detection signal from which a fluctuation component equal to or greater than the gain intersection is removed, and a gap length between the information recording medium and the optical system are controlled using the correction gap detection signal. That and a gap control unit.
- a correction gap detection signal is created by removing a fluctuation component equal to or greater than the gain intersection of the power control unit from the gap detection signal, and the correction gap detection signal is used to generate a gap between the information recording medium and the optical system. Since the gap length is controlled, it is possible to accurately detect gap fluctuations by eliminating the effects of light quantity fluctuations that are not caused by gap fluctuations, and stable gap control based on these accurate gap fluctuations. It can be performed. As a result, stable operation of gap control can be secured without being affected by power fluctuations that cannot be suppressed by the power control unit, so fluctuations not caused by gap fluctuations can be reduced, and gap control can be performed stably. It can be carried out.
- the correction unit removes the fluctuation component extracted by the filter unit from the gap detection signal and a filter unit that extracts a fluctuation component that is greater than or equal to the gain intersection of the power control unit from the power detection signal. It is preferable to include a fluctuation component removing unit that creates a gap detection signal.
- a fluctuation component equal to or higher than the gain intersection of the power control unit is extracted from the power detection signal, and the extracted fluctuation component is removed from the gap detection signal. It is possible to accurately detect the gap variation without being affected.
- a gap control method for an optical information device is a gap control method for an optical information device that records and / or reproduces information using an information recording medium, and the output power of a light source that emits light.
- a first step of detecting a power to generate a power detection signal, a second step of controlling an emission power of the light source using the power detection signal, and the information recording using light from the light source A third step of generating a gap detection signal by detecting a gap length between an optical system for forming a beam spot of a predetermined size on the medium and the information recording medium, and using the gap detection signal
- a fourth step of controlling a gap length between the information recording medium and the optical system, and a power control gain intersection in the second step is defined in the fourth step. Greater than the gain intersection of the gap control.
- a gap control method for another optical information apparatus is a gap control method for an optical information apparatus that records and / or reproduces information using an information recording medium, and includes a light source that emits light.
- a fifth step of controlling the gap length between the broadcast recording medium and the optical system is a fifth step of controlling the gap length between the broadcast recording medium and the optical system.
- a corrected gap detection signal is created by removing a fluctuation component equal to or greater than the power control gain intersection from the gap detection signal, and the correction gap detection signal is used to generate a gap between the information recording medium and the optical system. Since the gap length is controlled, it is possible to accurately detect gap fluctuations by eliminating the effects of light intensity fluctuations that are not caused by gap fluctuations, and stable gap control based on these accurate gap fluctuations. It can be carried out. As a result, stable operation of gap control can be secured without being affected by power fluctuations that cannot be suppressed by power control, so fluctuations not caused by gap fluctuations are reduced and gap control is stably performed. be able to.
- the optical information apparatus can realize stable gap control that is not affected by fluctuations in laser power, so that an optical information apparatus that records and / or reproduces information using an information recording medium, for example, an optical disc It is useful as an optical disk device for recording and / or reproducing information.
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Abstract
Description
図1は、本発明の実施の形態1による光ディスク装置の構成を示す概略図である。図1に示す光ディスク装置は、SIL2、対物レンズ3、SIL2と対物レンズ3とを連結する固定具4、ギャップ制御用アクチュエータ7、偏光ビームスプリッタ9、ディテクタ10、コリメートレンズ11、λ/4板12、レーザ14、ギャップ制御回路15、ビームスプリッタ25、ディテクタ26、レーザパワー制御回路27、及び電源28を備える。また、レーザパワー制御回路27は、レーザ14を駆動するレーザ駆動回路27aを備える。
次に、本発明の実施の形態2による光ディスク装置について説明する。本実施の形態は、金属チップに光ビームを照射することにより発生するプラズモン光を利用して光ディスクへの記録再生(プラズモン方式による記録再生)を行う光ディスク装置である。
次に、本発明の実施の形態3による光ディスク装置について説明する。図7は、本発明の実施の形態3による光ディスク装置の構成を示す概略図である。図7に示す光ディスク装置は、SIL2、対物レンズ3、SIL2と対物レンズ3とを連結する固定具4、ギャップ制御用アクチュエータ7、偏光ビームスプリッタ9、ディテクタ10、コリメートレンズ11、λ/4板12、光源の一例であるレーザ14、ギャップ制御回路15、ビームスプリッタ25、ディテクタ26、レーザパワー制御回路27b、電源28、フィルタ35及び加算器36を備える。
Claims (9)
- 情報記録媒体を用いて情報を記録及び/又は再生する光情報装置であって、
光を出射する光源と、
前記光源からの光を用いて、前記情報記録媒体上に所定の大きさのビームスポットを形成する光学系と、
前記光源の出射パワーを検出してパワー検出信号を作成するパワー検出部と、
前記パワー検出信号を用いて、前記光源の出射パワーを制御するパワー制御部と、
前記情報記録媒体と前記光学系との間のギャップ長を検出してギャップ検出信号を作成するギャップ検出部と、
前記ギャップ検出信号を用いて、前記情報記録媒体と前記光学系との間のギャップ長を制御するギャップ制御部とを備え、
前記パワー制御部は、前記ギャップ制御部のゲイン交点より大きいゲイン交点を有することを特徴とする光情報装置。 - 前記パワー制御部は、前記ギャップ制御部のゲイン交点の10倍以上のゲイン交点を有することを特徴とする請求項1に記載の光情報装置。
- 前記光源を駆動するための電力を供給する電源をさらに備え、
前記パワー制御部は、前記電源からのノイズの周波数より高いゲイン交点を有することを特徴とする請求項1又は2に記載の光情報装置。 - 前記ギャップ検出信号から前記情報記録媒体と前記光学系との間のギャップの変動に起因しない変動成分を除去した補正ギャップ検出信号を作成する補正部をさらに備え、
前記ギャップ制御部は、前記補正ギャップ検出信号を用いて、前記情報記録媒体と前記光学系との間のギャップ長を制御することを特徴とする請求項1~3のいずれかに記載の光情報装置。 - 前記補正部は、
前記パワー検出信号から前記光源の出射パワーの変動成分を抽出するフィルタ部と、
前記ギャップ検出信号から前記フィルタ部により抽出された変動成分を除去することにより、前記補正ギャップ検出信号を作成する変動成分除去部とを含むことを特徴とする請求項4に記載の光情報装置。 - 情報記録媒体を用いて情報を記録及び/又は再生する光情報装置であって、
光を出射する光源と、
前記光源からの光を用いて、前記情報記録媒体上に所定の大きさのビームスポットを形成する光学系と、
前記光源の出射パワーを検出してパワー検出信号を作成するパワー検出部と、
前記パワー検出信号を用いて、前記光源の出射パワーを制御するパワー制御部と、
前記情報記録媒体と前記光学系との間のギャップ長を検出してギャップ検出信号を作成するギャップ検出部と、
前記ギャップ検出信号から前記パワー制御部のゲイン交点以上の変動成分を除去した補正ギャップ検出信号を作成する補正部と、
前記補正ギャップ検出信号を用いて、前記情報記録媒体と前記光学系との間のギャップ長を制御するギャップ制御部とを備えることを特徴とする光情報装置。 - 前記補正部は、
前記パワー検出信号から前記パワー制御部のゲイン交点以上の変動成分を抽出するフィルタ部と、
前記ギャップ検出信号から前記フィルタ部により抽出された変動成分を除去することにより、前記補正ギャップ検出信号を作成する変動成分除去部とを含むことを特徴とする請求項6に記載の光情報装置。 - 情報記録媒体を用いて情報を記録及び/又は再生する光情報装置のギャップ制御方法であって、
光を出射する光源の出射パワーを検出してパワー検出信号を作成する第1のステップと、
前記パワー検出信号を用いて、前記光源の出射パワーを制御する第2のステップと、
前記光源からの光を用いて、前記情報記録媒体上に所定の大きさのビームスポットを形成する光学系と、前記情報記録媒体との間のギャップ長を検出してギャップ検出信号を作成する第3のステップと、
前記ギャップ検出信号を用いて、前記情報記録媒体と前記光学系との間のギャップ長を制御する第4のステップとを含み、
前記第2のステップにおけるパワー制御のゲイン交点は、前記第4のステップにおけるギャップ制御のゲイン交点より大きいことを特徴とする光情報装置のギャップ制御方法。 - 情報記録媒体を用いて情報を記録及び/又は再生する光情報装置のギャップ制御方法であって、
光を出射する光源の出射パワーを検出してパワー検出信号を作成する第1のステップと、
前記パワー検出信号を用いて、前記光源の出射パワーを制御する第2のステップと、
前記光源からの光を用いて、前記情報記録媒体上に所定の大きさのビームスポットを形成する光学系と、前記情報記録媒体との間のギャップ長を検出してギャップ検出信号を作成する第3のステップと、
前記ギャップ検出信号から前記第2のステップにおけるパワー制御のゲイン交点以上の変動成分を除去した補正ギャップ検出信号を作成する第4のステップと、
前記補正ギャップ検出信号を用いて、前記情報記録媒体と前記光学系との間のギャップ長を制御する第5のステップとを含むことを特徴とする光情報装置のギャップ制御方法。
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PCT/JP2012/001844 WO2012127831A1 (ja) | 2011-03-22 | 2012-03-16 | 光情報装置及びそのギャップ制御方法 |
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US (1) | US8854939B2 (ja) |
JP (1) | JPWO2012127831A1 (ja) |
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US10466962B2 (en) * | 2017-09-29 | 2019-11-05 | Sonos, Inc. | Media playback system with voice assistance |
DE202018103762U1 (de) | 2018-07-02 | 2018-09-07 | Tadbik Advanced Technologies Ltd. | Ein reißresistentes Identifikationsband |
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JPH06236576A (ja) * | 1992-12-16 | 1994-08-23 | Matsushita Electric Ind Co Ltd | レーザパワー制御装置及び制御方法 |
JP2002319156A (ja) * | 2001-04-19 | 2002-10-31 | Sony Corp | 信号記録装置、信号再生装置、及びそれらの方法 |
JP2002319153A (ja) * | 2001-04-19 | 2002-10-31 | Sony Corp | 信号再生装置及びその信号検出方法 |
JP2002319160A (ja) * | 2001-04-23 | 2002-10-31 | Sony Corp | 信号記録装置及び信号記録方法、並びに、信号再生装置及び信号再生方法 |
JP2004335064A (ja) * | 2003-05-12 | 2004-11-25 | Sony Corp | 情報記録装置及び方法、情報再生装置及び方法 |
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JP2001023190A (ja) * | 1999-07-07 | 2001-01-26 | Sony Corp | 露光装置、露光方法、光ディスク装置、及び記録及び/又は再生方法 |
JP2009158007A (ja) * | 2007-12-26 | 2009-07-16 | Sony Corp | 光学ピックアップ装置、光記録再生装置及びギャップ制御方法 |
KR20090077145A (ko) * | 2008-01-10 | 2009-07-15 | 삼성전자주식회사 | 근접장 광기록/재생 장치 및 상기 장치의 갭 에러 신호정규화 방법 |
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- 2012-03-16 WO PCT/JP2012/001844 patent/WO2012127831A1/ja active Application Filing
- 2012-03-16 JP JP2013505809A patent/JPWO2012127831A1/ja active Pending
- 2012-03-16 CN CN2012800140218A patent/CN103430236A/zh active Pending
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
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JPH06236576A (ja) * | 1992-12-16 | 1994-08-23 | Matsushita Electric Ind Co Ltd | レーザパワー制御装置及び制御方法 |
JP2002319156A (ja) * | 2001-04-19 | 2002-10-31 | Sony Corp | 信号記録装置、信号再生装置、及びそれらの方法 |
JP2002319153A (ja) * | 2001-04-19 | 2002-10-31 | Sony Corp | 信号再生装置及びその信号検出方法 |
JP2002319160A (ja) * | 2001-04-23 | 2002-10-31 | Sony Corp | 信号記録装置及び信号記録方法、並びに、信号再生装置及び信号再生方法 |
JP2004335064A (ja) * | 2003-05-12 | 2004-11-25 | Sony Corp | 情報記録装置及び方法、情報再生装置及び方法 |
Also Published As
Publication number | Publication date |
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US8854939B2 (en) | 2014-10-07 |
CN103430236A (zh) | 2013-12-04 |
JPWO2012127831A1 (ja) | 2014-07-24 |
US20140003222A1 (en) | 2014-01-02 |
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