CN101443845B - Recording/reproducing apparatus and tracking control method - Google Patents
Recording/reproducing apparatus and tracking control method Download PDFInfo
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- CN101443845B CN101443845B CN2007800172256A CN200780017225A CN101443845B CN 101443845 B CN101443845 B CN 101443845B CN 2007800172256 A CN2007800172256 A CN 2007800172256A CN 200780017225 A CN200780017225 A CN 200780017225A CN 101443845 B CN101443845 B CN 101443845B
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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
- G11B7/0925—Electromechanical actuators for lens positioning
- G11B7/0929—Electromechanical actuators for lens positioning for tracking 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
- G11B7/08—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
- G11B7/0925—Electromechanical actuators for lens positioning
- G11B7/0935—Details of the moving parts
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Abstract
A recording/reproducing apparatus and a tracking control method which can perform data processing for reliably recording or reproducing data on or from a recording medium are disclosed. Tracking error signal (TE) is generated using difference signal (A-B) produced from reflected light from a recording medium and an offset included in the difference signal is compensated for using another reflected light received separately from the reflected light. Offset-compensated tracking error signal ((A-B)-k(C-D)) is obtained by subtracting another difference signal (C-D) produced from the separately received reflected light according to gain (k) from difference signal (A-B). Different gains may be used for areas on the recording medium having different reflectances. Thus, the tracking error signal can be compensated for an optical offset caused by lens movement and an offset caused by different reflectances and light radiated to the recording medium can accurately follow its track to perform reliable data processing.
Description
Technical field
The present invention relates to a kind of data recording/reproducing device and tracking and controlling method thereof, relate more particularly to a kind of be used to carry out to or from the recording medium reliable recording or reproduce data data processing device and be used for the tracking and controlling method of this device.
Background technology
Data recording/reproducing device be carry out to or from such as recording medium recording such as the CD that comprises Zip disk (CD) or digital multi disk (DVD) or reproduce the equipment of the data processing of data.Need this data recording/reproducing device to carry out tracking Control, so as when following the recording medium track, to carry out be used for to or from recording medium recording or reproduce the data processing of data.
Traditional tracking Control is like this used i-beam push-pull method.Describe this i-beam push-pull tracking Control in detail now with reference to Fig. 1.Incide fluorescence detector 300 from the laser beam of recording medium reflection by object lens 200.The fluorescence detector 300 that is divided into two regional A and B will convert electric signal to by the laser beam that regional A and B receive, and they are exported as signal A and B.Difference signal between signal A and the B is used as tracking error signal (TE).When laser beam was positioned at the center of track, the amplitude of tracking error signal was minimized (being TE=0).Therefore, by about recording medium flatly move left and right object lens 2 carry out tracking Control so that make the amplitude of tracking error signal (TE) minimize (being TE=0).This makes it possible to control laser beam and follow track under the situation of not deorbit.
But this classic method has following problem.
In i-beam push-pull method, when move left and right object lens flatly, incide the also move left and right flatly of laser beam on the fluorescence detector, thereby cause the optical shift between regional A and the B.Because not changing with the signal that is caused by tracking error, this optical shift do not separate, so this optical shift causes error during tracking Control for centrifugal recording medium (eccentric recording medium).
In addition, owing to optical shift does not separate with the signal variation that deorbit when carrying out real-Time Tracking Control causes, so this optical shift causes error during tracking Control for centrifugal recording medium.
In addition, optical shift changes according to the light intensity from recording medium reflection.Be difficult to eliminate such as re-writable recording medium etc. and comprise non-posting field and have the two the optical shift of recording medium of posting field of antiradar reflectivity with high reflectance.
Summary of the invention
Be designed to solve a kind of light that is used to allow to shine recording medium of the object of the present invention is to provide of described problem and accurately follow track on the recording medium to carry out the method and apparatus of reliable data processing.
Be designed to solve described problem another object of the present invention is to provide a kind of tracking error signal (TE) that is used to calculate the compensate for optical skew accurately to follow the method and apparatus of track in the above described manner with the light that allows irradiation.
The of the present invention further purpose that is designed to solve described problem is to provide a kind of tracking error signal (TE) that is used to calculate the optical shift in the zone that has different reflectivity on the compensation recording medium accurately to follow the method and apparatus of track with the light that allows irradiation.
Purpose of the present invention can obtain by a kind of tracking and controlling method is provided, this tracking and controlling method uses the tracking error signal (TE) that received reflected light generates after recording medium reflection to control light to follow the track of recording medium, wherein said reflected light is separated into first and second reflected light, and use the difference signal that produces from second reflected light to generate described tracking error signal (TE), use first reflected light that receives discretely with second reflected light to compensate the skew that is included in the difference signal.Here, preferably, the light that shines recording medium is by high refractive index lens, so that the part of irradiates light distortion (distorted), and is used as first reflected light from the distortion light of recording medium reflection and receives discretely.In addition, preferably, generate tracking error signal (TE) by deducting the difference signal that produces from first reflected light according to gain the difference signal that produces from second reflected light.
Preferably, determine gain (k) by the ratio that moves according to lens between the variation of the variation of the difference signal that produces from first reflected light and the difference signal that produces from second reflected light.Gain (k) can also be by definite to get off: (TE) applies sine wave to tracking error signal, and determines to make the minimized yield value of maximum and the interval between the minimum value that comprises to the tracking error signal (TE) of its sine wave that applies then when changing yield value.
In another aspect of this invention, provide a kind of tracking and controlling method, having comprised: will be separated into first and second reflected light from the light of recording medium reflection, and receive described first and second reflected light at this; Generate tracking error signal: TE=(A-B)-k (C-D) by following equation, wherein, first difference signal that " (A-B) " expression produces from described first reflected light, second difference signal that " (C-D) " expression produces from described second reflected light, and " k " expression gains accordingly with ratio between first and second difference signals variation of moving according to lens; Wherein, described gain is by definite to get off: sine wave is put on described tracking error signal, and determine to make then when changing the value of described gain and comprise to the maximum of the tracking error signal of its sine wave that applies and the value of the minimized gain in interval between the minimum value; And use described tracking error signal to control light to follow the track on the described recording medium.
In also one side of the present invention, provide a kind of data recording/reproducing device at this, comprise: optical separator, the light that is used for being received is separated into folded light beam, described only the lens lighting by being positioned at same position after recording medium from described recording medium reflection; First and second fluorescence detectors are used to receive separated folded light beam; Signal generator, be used for generating tracking error signal: TE=(A-B)-k (C-D) by following equation, wherein, first difference signal that " (A-B) " expression produces from described first reflected light, second difference signal that " (C-D) " expression produces from described second reflected light, and " k " expression gains accordingly with ratio between first and second difference signals variation of moving according to lens; Wherein, described gain is by definite to get off: sine wave is put on described tracking error signal, and determine to make then when changing the value of described gain and comprise to the maximum of the tracking error signal of its sine wave that applies and the value of the minimized gain in interval between the minimum value; And controller, be used for exporting control signal to follow the track on the described recording medium according to described tracking error signal.
Description of drawings
Comprised that the accompanying drawing that is used to provide further understanding of the present invention shows embodiments of the invention, and be used for explaining principle of the present invention with instructions.
In described accompanying drawing:
Fig. 1 shows the example as the i-beam push-pull method of traditional tracking and controlling method.
Fig. 2 shows the structure according to the data recording/reproducing device of the embodiment of the invention.
Fig. 3 shows according to the recording medium in the data recording/reproducing device and the optical system of optical pickup (pickup) of being included in of the present invention.
Fig. 4 shows schematic sectional view according to the lens unit of the optical pickup of first embodiment of the invention together with recording medium.
Fig. 5 shows the method that is used for generating at data recording/reproducing device tracking error signal according to the embodiment of the invention.
Fig. 6 A and 6B show the example of detected tracking error signal.
Fig. 7 shows how to generate tracking error signal according to an embodiment of the invention in data recording/reproducing device.
Fig. 8 A～8C shows first embodiment according to the method for the gain that is used for determining tracking error signal generating method of the present invention.
Fig. 9 A～9C shows second embodiment according to the method for the gain that is used for determining tracking error signal generating method of the present invention.
Figure 10 shows the 4th embodiment according to the method for the gain that is used for determining tracking error signal generating method of the present invention.
Embodiment
To carry out detailed reference to the preferred embodiment of data recording/reproducing device according to the present invention and tracking and controlling method thereof now, its example is shown in the drawings.Above and other purpose of the present invention, feature and other advantage will be understood more thoroughly by the following detailed description in conjunction with the accompanying drawings embodiment.
Though the most of terms that use among the present invention are selected from widely used general terms in this area, some terms have passed through applicant's arbitrary selection, and its meaning will be explained as required and in the following description in detail.Therefore, should utilize the prospective significance of term but not its simple name or meaning are understood the present invention.
Data recording/reproducing device according to the present invention is constructed to light shine recording medium, with carry out to or from the recording layer record of recording medium or reproduce the data processing of data.For accurate and reliable data processing, need come the position that is mapped to by illumination on the controlling recording mechanism by optical pickup.
In the present invention, data recording/reproducing device is constructed to the light from recording medium reflection is separated into a plurality of light beams and receives separated light beam, carry out tracking Control according to the tracking error signal (TE) that produces by the light beam that receives discretely then, be mapped to accurate position on the recording medium to allow illumination.Though will be that example is described the present invention in detail to separate and to receive from the surface of recording medium and the near-field recording/transcriber of recording layer beam reflected, the present invention can be applied to other data recording/reproducing device in the same way.The term that uses among the present invention " data recording/reproducing device " refer to can to or from recording medium recording or reproduce any device of data.The term that uses among the present invention " recording medium " refers to any data storage medium, for example comprises the medium such as any record types such as CD, disk or tapes.Though, for convenience of explanation, will the invention is not restricted to use the data recording/reproducing device of near field of light with the data recording/reproducing device that uses near field of light example in an embodiment of the present invention as data recording/reproducing device.
To carry out detailed reference to the preferred embodiment according to data recording/reproducing device of the present invention now, its example is shown in the drawings.As possible, will use identical Reference numeral to refer to same or analogous part in the accompanying drawing from start to finish.
Fig. 2 schematically shows the structure of data recording/reproducing device according to an embodiment of the invention.It below is detailed description with reference to the structure of the data recording/reproducing device of Fig. 2 and other accompanying drawing.
Optical pickup (P/U) 1 light shines recording medium and receives light from recording medium reflection, generates corresponding signal then.The example constructions that is included in the optical system in the optical pickup 1 is illustrated among Fig. 3.The optical system that is included in the optical pickup 1 can comprise light source 10, separation/ composite part 20 and 30, lens unit 40 and fluorescence detector 60 and 70.To describe the parts of optical pickup 1 now in detail.
Can be almost parallel with producing, the laser instrument of the coherent light beam of high concentration is as light source 10.Specifically, can be with laser diode as light source 10.Optical pickup 1 can also comprise the lens such as collimating apparatus, and it is arranged on the path of the light beam that sends from light source 10 so that institute's emitted light beams is parallel to each other, and is parallel to each other so that shine the light beam of recording medium.
The beam separation that separation/ composite part 20 and 30 will incident on same direction or the light beam of incident in different directions are synthetic.In the present embodiment, optical pickup 1 comprises the first and second separation/composite parts 20 and 30.It below is the detailed description of the first and second separation/composite parts 20 and 30.The part that the first separation/composite part 20 makes incident beam by and reflect its another part.For example, can be with nonpolarized light beam splitter (NBS) as the first separation/composite part 20.Second separation/the composite part 30 only makes that the light of polarization passes through on specific direction.For example, can be with polarization beam splitter (PBS) as the second separation/composite part 30.Specifically, the second separation/composite part 30 vertical polarization component that can be constructed to make linearly polarized photon by and reflect its horizontal polarization component.The horizontal polarization component that the second separation/composite part 30 can also be constructed to make linearly polarized photon by and reflect its vertical polarization part.
The optical system that comprises the optical pickup of lens unit 40 is positioned at the position that is in close proximity to recording medium 50.It below is detailed example.If lens unit 40 and recording medium 50 are positioned at the distance less than about 1/4 optical wavelength (being λ/4), scioptics the unit 40 and evanescent wave that produces can keep its feature so that it can be used for record and reproduce then.But if lens unit 40 and recording medium 50 are positioned at the distance greater than λ/4, then the light from lens unit 40 irradiations loses the feature of evanescent wave and gets back to its first-harmonic.Therefore, use the data recording/reproducing device of near field of light to remain on the interval between lens unit 40 and the recording medium 50 usually so that be no more than about λ/4 as the scope of near field of light.
The signal that use is generated by optical pickup 1, as shown in Figure 2, signal generator 2 generates required RF signal and required gap error signal (GE) and the tracking error signal (TE) of servocontrol of data reproduction.Signal generator 2 can be constructed to compensate the skew in the signal that may be included in generation, and therefore generates the migration signal.For example, signal generator 2 can be constructed to compensate owing to lens move the skew that is included in the optical shift in the tracking error signal (TE) or is caused by catoptrical varying strength that causes.Migration can also be carried out by controller 3 or other parts except that signal generator 2.Describe with reference to the accompanying drawings by signal generator 2 after a while and generate Signal Processing.
Controller 3 receives by fluorescence detector 60 and 70 or the signal that generated by signal generator 2, and generates control or drive signal.For example, controller 3 is handled gap error signal (GE), and the drive signal that will be used to be controlled at the interval between lens unit 40 and the recording medium 50 outputs to gap servo driver 4.Controller 3 is also handled tracking error signal (TE), and the drive signal that will be used for tracking Control outputs to tracking servo driver 5.
Gap servo driver 4 drives the actuator (not shown) in the optical pickups 1, so that make lens unit 40 vertical moving in optical pickup 1 or the optical pickup 1.This makes and can make the interval between lens unit 40 and recording medium 50 keep constant.Gap servo driver 4 can the double as focus servo.For example, according to the signal that is used for focus control that comes self-controller 3, gap servo driver 4 can allow the lens unit 40 in optical pickup 1 or the optical pickup 1 to follow the vertical moving of recording medium 50 when recording medium 50 rotations.
The tracking actuator (not shown) that tracking servo driver 5 drives in the optical pickup 1 is so that the position that the lens unit 40 in optical pickup 1 or the optical pickup 1 moves the light on the correction entries medium 50 diametrically.This allows the lens unit 40 in optical pickup 1 or the optical pickup 1 to follow the track that is limited on recording medium 50.In response to track shift command, tracking servo driver 5 can make the lens unit 40 in optical pickup 1 or the optical pickup 1 move diametrically.
In response to track shift command, stepping (sled) servo-driver 6 can move radially optical pickup 1 by stepping motor (sled motor) (not shown) that drives for optical pickup 1 being moved provide.
Can will be connected to such data recording/reproducing device such as main frames such as PC.This main frame sends to microcomputer 100 by interface with the recoding/reproduction order, and from the data of demoder 7 receptions through reproducing, and the data that will write down send to scrambler 8.According to recoding/reproduction order from main frame, microcomputer 100 control demoder 7, scrambler 8 and controllers 3.
Usually, can using advance technology additional packet interface (ATAPI) 110 as described interface.ATAPI 110 is at main frame and such as the standard interface between the optic recording/reproducing devices such as CD or DVD driver.The data that this standard interface has been proposed to be decoded by optic recording/reproducing device send to main frame, and act as will be decoded data-switching become can be by the integrated data of host process.
To and describe the operating process of data recording/reproducing device in detail with reference to the signal flow in other parts about the direction of propagation or the path of the light of the light source from optical system 10 emission now.
The light of light source 10 emissions from pick-up head 1 incides on the first separation/composite part 20.The part of incident light is from the reflection of the first separation/composite part 20, its another part by this first separation/composite part 20 so that incide on the second separation/composite part 30.Second separation/the composite part 30 passes through and the reflection levels polarized component vertical polarization component of horizontal polarization light.Second separation/the composite part 30 can also be constructed to make the horizontal polarization component to pass through and reflection vertical polarization component.Can also in the path of the light by the second separation/composite part 30, provide polarization to change plate (polarization change plate) (not shown).The details that this polarization changes plate will be described after a while.
Light by the second separation/composite part 30 incides on the lens unit 40.The light that incides on the object lens in the lens unit 40 generates lens to generate evanescent wave by the near field.Specifically, incide the near field with angle and generate light total reflection between the surface of the surface of lens and recording medium 50 on the lens greater than threshold angle.On the other hand, incide the near field with threshold angle or following angle and generate light on the lens from the recording layer reflection of recording medium 50.The evanescent wave that produces in this process arrives the recording layer of recording medium, with executive logging/reproduction.
Incide on the second separation/composite part 30 from the light scioptics unit 40 of recording medium 50 reflections.As mentioned above, can in the path of the light on inciding the second separation/composite part 30, provide polarization to change the plate (not shown).This polarization changes plate and changes light that incides on the recording medium 50 and the polarisation of light direction that has reflected from recording medium 50.For example, when quarter-wave plate (QWP) was changed plate as polarization, its left-handed polarization circularly incided the light on the recording medium 60, and dextrorotation circularly polarization from the light of recording medium 60 reflections, to propagate into incident light in the opposite direction.As a result, polarization of reflected light direction and the polarization of incident light direction by quarter-wave plate differs an angle of 90 degrees.When the vertical polarization component that incident light is only arranged passed through the second separation/composite part 30, light only had the horizontal polarization component when it has got back to the second separation/composite part 30 after recording medium 50 is reflected.Therefore, the second separation/composite part 30 will have the back light reflection of horizontal polarization component, to incide on second fluorescence detector 70.Simultaneously since according to the numerical aperture of the lens unit in near-field recording/transcriber of the present invention 40 greater than " 1 ", polarisation of light illuminated and scioptics unit 40 and reflex time distortion at it.That is to say, incide a catoptrical part on the second separation/composite part 30, so it is by the second separation/composite part 30 also owing to polarization distortion has the vertical polarization component.After passing through the second separation/composite part 30, reflected light incides the first separation/composite part 20.The part that the first separation/composite part 20 makes incident light by and reflect its another part.Incide first fluorescence detector 60 from the light of the first separation/composite part, 20 reflections.
Now detailed description is used to generate tracking error signal (TE) and carries out tracking Control with reliable recording and method of reproducing data.At first, describe the detailed example of the method that is used to generate tracking error signal (TE) with reference to accompanying drawing, described tracking error signal (TE) is used for tracking Control accurately.
Fig. 5 shows the method that is used for generating at data recording/reproducing device tracking error signal (TE) according to an embodiment of the invention.Also describe tracking error signal generating method in detail with reference to Fig. 6 and 7, in described Fig. 6 and 7, identical Reference numeral is used to refer to same or similar part.As shown in Figure 5, in first and second fluorescence detectors 60 and 70 each can be divided into two or four detecting elements in the zones of different, and can carry out various modifications as required.
In the present embodiment, use from the signal of second fluorescence detector, 70 outputs, signal generator 2 can be according to above generating tracking error signal (TE) with reference to the described single beam method of recommending of Fig. 1.The details of this method is as follows.
This method is based on such fact: promptly, the light of signal on inciding recording medium 50 that is produced by the light from recording medium 50 reflection provides the optical profile of balance and symmetry when being positioned at its orbit centre, and asymmetrical optical profile is provided when incident light departs from aforesaid orbit centre.Therefore, can with from poor (A-B) between the level of the signal A of second fluorescence detector 70 output and B as tracking error signal (TE) as the error signal that is used for tracking Control, whether described poor (A-B) indication output signal symmetrical.Therefore, can make lens unit 40 about recording medium 40 and when moving horizontally control lens unit 40 follow track so that tracking error signal (TE) is minimized.
Can comprise optical shift by second fluorescence detector, 70 detected tracking error signals (TE).Specifically, when not having optical shift, can generate the amplitude that has as shown in Fig. 6 A by second fluorescence detector, 70 detected tracking error signals (TE) is the sine wave of " A1 ".Indicated as " A1 " among Fig. 6 A and the 6B and " A2 ", employed term " amplitude " refers to vibration signal and its minimum value but not the maximum displacement of its mean value in the instructions of the present invention.On the other hand, when lens unit 40 moved, tracking error signal moved according to it and changes, and to generate the sine wave that becomes with minimum and maximum value, described minimum and maximum value has the interval of " A2 " approximately between it as shown in Fig. 6 B.When the tracking error signal (TE) that uses as Fig. 6 B as shown in, be difficult to carry out tracking Control accurately, and error also take place when carrying out tracking Control at use tracking error signal (TE).
Therefore, need the tracking error signal offset of compensation image 6B, described tracking error signal is the component that moves the signal that changes according to lens unit 40, thereby detects the sine wave as shown in Fig. 6 A.For realizing this, the optical shift that the signal that the present invention's use is detected by first fluorescence detector 60 comes compensatory tracking error signal (TE).
Fig. 7 schematically shows and wherein uses the signal that is detected by first fluorescence detector 60 to compensate the tracking error signal (TE) that is detected by second fluorescence detector 70 and eliminate by the mobile skew that causes of lens unit 40 method with the tracking error signal (TE) that generates compensating offset.
As shown in Figure 7, in the present invention, first and second fluorescence detectors 60 separate with in 70 each and receive light illuminated and that reflect with the lens unit 40 that is positioned at same position.Therefore, flatly during move left and right, incide reflected light and the horizontal synergistically move left and right of reflected light that incides on second fluorescence detector 70 on first fluorescence detector 60 at lens unit 40.Therefore, can use the reflected light that detects by first fluorescence detector 60 to detect and move the optical shift that causes by lens.Can be by compensate the tracking error signal (TE) that the difference signal that is detected by second fluorescence detector 70 detects compensating offset for the skew that is detected.Here, described difference signal refers to the tracking error signal (TE) that is detected by second fluorescence detector 70.The details of this method is as follows.
[equation 1]
TE＝(A-B)-k(C-D)
That is to say that signal generator 2 deducts the product of gain " k " and the difference signal of exporting from first fluorescence detector 60 (C-D) from the difference signal (A-B) that is generated by second fluorescence detector 70.And poor (C-D) the proportional value " k (C-D) " between signal C and the D moves the optical shift component that cause by lens corresponding to being included in the difference signal (A-B).Gain " k " is corresponding to the ratio between the variation separately that moves according to lens by first and second fluorescence detectors 60 and 70 two difference signals that generate.For the record and the non-posting field of recording medium, gain " k " has different values.
In the present embodiment, the signal from the output of first fluorescence detector 60 can be used for holding the record interval (or gap) between medium 50 and the lens unit 40.Specifically, signal generator 2 shown in Fig. 2 is by generating gap error signal (GE) to the signal summation from the output of first fluorescence detector 60, and can gap error signal (GE) is constant comes the interval maintenance between controlling recording medium 50 and the lens unit 40 constant by keeping.The level of gap error signal (GE) corresponding to be outputted as have with the signal of the proportional level of intensity of reflected light and (C+D), can near field range, make the ratio that is partitioned between described level and recording medium 50 and the lens unit 40.In the present embodiment, can use the signal that detects by first fluorescence detector 60 that is provided to generate gap error signal (GE) to come compensatory tracking error signal (TE) for move the optical shift that causes by lens.
The detailed example of the method that is used for definite gain " k " is described below.
First embodiment of the method that is used for definite gain " k " is described now with reference to Fig. 8 A～8C.First and second fluorescence detectors 60 and 70 receive reflected light and convert this reflected light to electric signal, and this electric signal is exported as signal AC (RF) signal.According to present embodiment, can come calculated gains " k " by the variation of in any mobile lens unit 40, directly measuring by first and second fluorescence detectors 60 and 70 signals that generate.
Fig. 8 A～8C shows the variation of the difference signal (C-D) that generates according to the variation of moving the difference signal (A-B) that is generated by second fluorescence detector 70 of lens unit 40 with by first fluorescence detector 60.Specifically, Fig. 8 A shows the variation of the difference signal when lens unit 40 moves to left, Fig. 8 B shows the variation of the difference signal when lens unit 40 is positioned at the corresponding position of orbit centre, and Fig. 8 C shows the variation of the difference signal when lens unit 40 moves to right.Because tracking error signal (TE) is the AC signal, the mean value of the AC signal of output illustrates by solid line so that illustrate, and detects the variation of this mean value.
When lens unit 40 moves to left from the position corresponding to orbit centre of lens unit 40 as shown in 8B or during the right, if " X " expression is by the variation of the mean value of the difference signal (A-B) of second fluorescence detector, 70 generations, " Y " expression then can be used as equation 2 represented methods and be obtained gain " k " by the variation of the mean value of the difference signal (C-D) of first fluorescence detector, 60 generations.
[equation 2]
That is to say, flatly detect by first and second fluorescence detectors 60 and the 70 catoptrical variations that receive in the move left and right to a certain extent at lens unit 40.The variation by the difference signal that fluorescence detector generated is represented respectively in the variation that is detected.Therefore, can determine gain " k " by the ratio (specifically, being the ratio between the value separately that changes) that calculates between changing.
Second embodiment of the method that is used for definite gain " k " is described now with reference to Fig. 9 A～9C.Repeatedly in the horizontal side-to-side vibrations lens unit 40 sine wave is being put on the tracking error signal (TE=(A-B)-k (C-D)) that is detected.At first, gain " k " is fixed.Then, when changing gain " k ", detect by sine wave being put on the highest and minimum level of the signal that tracking error signal (TE) produces.The value of the gain " k " when then, the interval of detection between the highest and minimum level is minimized.
Fig. 9 A～9C shows the variation when flatly tracking error signal (TE) changes along with gain " k " during side-to-side vibrations lens unit 40 when sine wave being put on tracking error signal (TE).When gain " k " less than according to lens unit 40 move from the ratio " (A-B)/(C-D) " between the changing separately of the error signal of first and second fluorescence detectors 60 and 70 time, be not eliminated and stay in the error signal by the mobile variation that causes (i.e. skew) of lens unit 40.Therefore, as shown in Fig. 9 A, the tracking error signal that is detected (TE) has the polarity ground identical with the polarity of the sine wave that is applied and changes, and has big interval between the highest and minimum level.When gain " k " equal according to lens unit 40 move from the ratio " (A-B)/(C-D) " between the changing separately of the error signal of first and second fluorescence detectors 60 and 70 time, the mobile skew that causes by lens unit 40 is eliminated, and the tracking error signal that is detected (TE) has the sinusoidal waveform as shown in Fig. 6 A.Therefore, as shown in Fig. 9 B, the interval between the highest and minimum level of the tracking error signal that is detected (TE) (being the amplitude of signal (TE)) is minimized.On the other hand, when gain " k " greater than according to lens unit 40 move from the ratio " (A-B)/(C-D) " between the changing separately of the error signal of first and second fluorescence detectors 60 and 70 time, from error signal, deduct more than mobile caused skew by lens unit 40 from second fluorescence detector 70.
Therefore, as shown in Fig. 9 C, the tracking error signal that is detected (TE) has and the sinusoidal wave opposite polarity ground change that is applied, and has big interval between the highest and minimum level.
The value of the gain " k " in the time of can being minimized by the amplitude that finds tracking error signal when changing gain " k " value in fixed gain initially " k " afterwards and sine wave being put on tracking error signal (TE) is in the above described manner subsequently determined gain " k ".
On the other hand, for different intensities of reflected light, gain " k " has different values.Therefore, in order to carry out tracking Control, need determine the different value of gain " k " according to catoptrical intensity.The specific embodiment that is used for determining for the method for the different gains " k " of different intensities of reflected light is described below with reference to accompanying drawings.Though present embodiment will the invention is not restricted to such recording medium with the recording medium that comprises record that different intensities of reflected light are provided and non-posting field as an example.After the reflection of the recording layer (not shown) of recording medium 50 by the light intensity of second fluorescence detector, 70 receptions at light from having the non-posting field (not shown) reflex time height of high reflectance, low at light from posting field (not shown) reflex time with relatively low reflectivity.On the other hand, do not depend on only at the light intensity that after the surface reflection of recording medium 50, receives not to be reflected from posting field by first fluorescence detector 60, and have basis between lens unit 40 and recording medium 50 the interval and predetermined value.That is to say, when light when the zone with different reflectivity is reflected, only have second fluorescence detector 70 to receive the folded light beam of varying strength.Along with catoptrical intensity increases, the variation (X) of the difference signal (A-B) that is generated by second fluorescence detector 70 increases, therefore must modified gain " k ".
Use description to the 3rd embodiment of the method for definite gain " k " now.First gain " the k of posting field is determined in use according to the method for first or second embodiment
1".Use identical method to determine the second gain " k of non-posting field
2".In recoding/reproduction operating period, can utilize tracking error (TE) to carry out tracking Control, for posting field, this tracking error (TE) is used the first gain " k
1" generate, for non-posting field, this tracking error (TE) is used the second gain " k
2" generate.
Use description to the 4th embodiment of the method for definite gain " k " now.Determining the gain " k of posting field
1" afterwards, can calculate the gain " k of non-posting field according to ratio from record with different reflectivity and non-posting field intensity of light reflected
2", described ratio have and reflectivity between difference be worth accordingly.The details of this method is described with reference to Figure 10 hereinafter.
At first, determine the gain " k of posting field
1" (S10).This gain " k
1" can determine according to the method for first or second embodiment.Also can at first determine the gain " k of non-posting field
2" so that based on gain " k
2" next definite gain " k
1".
Detect light intensity (S20) for record and each of non-posting field by 70 receptions of second fluorescence detector.Then, determine ratio (S30) between light intensity (R) that in posting field, detects and the light intensity (N) that in non-posting field, detects.Gain " the k of non-posting field
2" can by as following equation 3 expressedly with the gain " k of posting field
1" multiply by determined light intensity ratio and calculate.
[equation 3]
Be recorded in example on the re-writable recording medium now with reference to data wherein and describe operation in detail according to near-field recording/transcriber of the present invention.The user activate servo in case service recorder/transcriber to or from recording medium recording or reproduce data.Here, the hypothetical record medium comprises the posting field that comprises data and does not comprise the non-posting field of data.The light scioptics unit 40 of light source 10 emission from data recording/reproducing device and shine recording medium 50 is so that be recorded in data on the rotating recording medium 50.
By the light from recording medium 50 reflections, first and second fluorescence detectors 60 and 70 produce electric signal.Signal generator 2 uses electric signal to produce tracking error signal (TE).Specifically, flatly in the move left and right lens unit 40, the variation that signal generator 2 detects by first and second fluorescence detectors 60 and 70 detected signals is with the gain " k of definite posting field in posting field
1".Use gain " k
1", signal generator 2 generates tracking error signal (TE), has eliminated by lens from this tracking error signal (TE) and has moved the skew that causes.When receiving tracking error signal (TE), controller is carried out the real-time follow-up servocontrol by the driving actuator (not shown), so that lens unit 40 moves diametrically to follow track.
After moving to non-posting field during the recording operation, signal generator 2 uses the gain " k of non-posting field
2" revise tracking error signal (TE).When the tracking error signal (TE) that receives through revising, controller 3 is carried out tracking servo control according to the signal of revising (TE), follows track to allow lens unit 40.By detecting the intensity of reflected light that receives by second fluorescence detector 70 for record and non-posting field also subsequently with the gain " k of posting field
1" ratio that multiply by the intensity of reflected light that is detected determines the gain " k of non-posting field
2".Gain " the k of non-posting field
2" can calculate before the data recording operation and be stored on the storer that is used for signal generator 2 then or be stored on the recording medium 50 to be used for data recording operation.Perhaps, can during the data recording operation at the gain " k that calculates and use non-posting field when posting field moves to non-posting field
2".
Use the gain calculating method of light intensity to be not limited to be divided into the recording medium of record and non-posting field, and can be applied to comprise any recording medium in the zone that the different light intensity degree is provided.
The invention provides data recording/reproducing device with various advantages and the tracking and controlling method that is used for this data recording/reproducing device.
For example, the light that shines recording medium can be followed the track on the recording medium exactly, to carry out reliable data processing.
In addition, can be for moving the optical shift that causes by lens or coming the compensatory tracking error signal by the skew that the different reflectivity in the zone on the recording medium causes.
It will be apparent to those skilled in the art that can modifications and variations of the present invention are under the situation that does not break away from the spirit or scope of the present invention.Therefore, this invention is intended to contain modifications and variations of the present invention, as long as they are in the scope of appended claims and equivalent thereof.
Claims (8)
1. tracking and controlling method comprises:
To be separated into first and second reflected light from the light of recording medium reflection, and receive described first and second reflected light;
Generate tracking error signal by following equation:
TE＝(A-B)-k(C-D)，
Wherein, first difference signal that " (A-B) " expression produces from described first reflected light, second difference signal that " (C-D) " expression produces from described second reflected light, and " k " expression gains accordingly with ratio between first and second difference signals variation of moving according to lens;
Wherein, described gain is by definite to get off: sine wave is put on described tracking error signal, and determine to make then when changing the value of described gain and comprise to the maximum of the tracking error signal of its sine wave that applies and the value of the minimized gain in interval between the minimum value; And
Use described tracking error signal to control light to follow the track on the described recording medium.
2. the method for claim 1, wherein shine the lens of the light of described recording medium by high index of refraction, so that the distortion of the part of described irradiates light, and will receive discretely as first reflected light from the distortion light of described recording medium reflection.
3. the method for claim 1 further comprises:
Generation is used to have first tracking error signal of first area of the described recording medium of first reflectivity; And
Generation is used to have second tracking error signal of second area of the described recording medium of second reflectivity different with first reflectivity,
Wherein, described first tracking error signal and described second tracking error signal such as following equation are explained:
TE
1＝(A-B)-k
1(C-D)
TE
2＝(A-B)-k
2(C-D)，
And the relation between the gain in described first and second zones of being used for is as described in the following equation:
Wherein, " TE
1" described first tracking error signal of expression, " TE
2" described second tracking error signal of expression, " k
1" gain of the described first area of expression, and " k
2" expression described second area gain.
4. data recording/reproducing device comprises:
Optical separator, the light that is used for being received is separated into folded light beam, described only the lens lighting by being positioned at same position after recording medium from described recording medium reflection;
First and second fluorescence detectors are used to receive separated folded light beam;
Signal generator is used for generating tracking error signal by following equation:
TE＝(A-B)-k(C-D)，
Wherein, first difference signal that " (A-B) " expression produces from described first reflected light, second difference signal that " (C-D) " expression produces from described second reflected light, and " k " expression gains accordingly with ratio between first and second difference signals variation of moving according to lens;
Wherein, described gain is by definite to get off: sine wave is put on described tracking error signal, and determine to make then when changing the value of described gain and comprise to the maximum of the tracking error signal of its sine wave that applies and the value of the minimized gain in interval between the minimum value; And
Controller is used for exporting control signal to follow the track on the described recording medium according to described tracking error signal.
5. device as claimed in claim 4, wherein, what described second fluorescence detector received separated folded light beam generates the RF signal in the lump; And
Described first fluorescence detector receives in the separated folded light beam another and also generates gap error signal.
6. device as claimed in claim 5, wherein, described first fluorescence detector receives from the light of the surface reflection of described recording medium, and described second fluorescence detector receives from the light of the recording layer reflection of described recording medium.
7. device as claimed in claim 4, wherein, described signal generator generates first tracking error signal of the first area of the described recording medium that is used to have first reflectivity; And second tracking error signal that generates the second area of the described recording medium be used to have second reflectivity different with first reflectivity.
8. device as claimed in claim 7, wherein, described first tracking error signal and second tracking error signal are represented by following equation:
TE
1＝(A-B)-k
1(C-D)
TE
2＝(A-B)-k
2(C-D)，
And relation between the gain in described first and second zones such as following equation are represented:
Wherein, " TE
1" expression first tracking error signal, " TE
2" expression second tracking error signal, " k
1" gain of the described first area of expression, and " k
2" expression described second area gain.
Applications Claiming Priority (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020060042750A KR20070109586A (en) | 2006-05-12 | 2006-05-12 | Recording and/or reproducing method and apparatus thereof |
| KR1020060042750 | 2006-05-12 | ||
| KR10-2006-0042750 | 2006-05-12 | ||
| KR1020060052578A KR20070118435A (en) | 2006-06-12 | 2006-06-12 | Near field recording and/or reproducing apparatus and tracking controlling method thereof |
| KR10-2006-0052578 | 2006-06-12 | ||
| KR1020060052578 | 2006-06-12 | ||
| PCT/KR2007/000451 WO2007132974A2 (en) | 2006-05-12 | 2007-01-25 | Recording/reproducing apparatus and tracking control method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101443845A CN101443845A (en) | 2009-05-27 |
| CN101443845B true CN101443845B (en) | 2010-12-29 |
Family
ID=39064076
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2007800172256A Expired - Fee Related CN101443845B (en) | 2006-05-12 | 2007-01-25 | Recording/reproducing apparatus and tracking control method |
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| Country | Link |
|---|---|
| KR (1) | KR20070109586A (en) |
| CN (1) | CN101443845B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1153378A (en) * | 1995-09-08 | 1997-07-02 | 三菱电机株式会社 | Optical head tracking error detection device |
| CN1479283A (en) * | 2002-08-26 | 2004-03-03 | 联发科技股份有限公司 | Gain correction device and method of differential push-pull type rail searching error signal |
-
2006
- 2006-05-12 KR KR1020060042750A patent/KR20070109586A/en not_active Application Discontinuation
-
2007
- 2007-01-25 CN CN2007800172256A patent/CN101443845B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1153378A (en) * | 1995-09-08 | 1997-07-02 | 三菱电机株式会社 | Optical head tracking error detection device |
| CN1479283A (en) * | 2002-08-26 | 2004-03-03 | 联发科技股份有限公司 | Gain correction device and method of differential push-pull type rail searching error signal |
Non-Patent Citations (1)
| Title |
|---|
| JP特开平5-258322A 1993.10.08 |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101443845A (en) | 2009-05-27 |
| KR20070109586A (en) | 2007-11-15 |
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