DE10007781C2 - disk drive - Google Patents

Description

The invention relates to a disk drive, which is a function of compensating for an inclination between one serving as a recording medium Disc and a head from which a beam of light is emitted.

Recently, optical disks have been paying attention drawn up as a solution to requirements enough for media to store information gen, which are more voluminous than conventional text or Sound information is. With conventional erasable optical disks are used as lead notes tion in the control such that a light beam for recording / playback on the middle of the track is formed when the disks are manufactured become. Because of the guide grooves, webs or nu on a disc in spiral or concentric Form formed. By using both webs  as well as grooves as recording tracks (web tracks and groove marks) can record twice Amount of information compared to when using only one of these realized as recording tracks become. There is also a procedure for connecting that of the webs and grooves in such a way that the Web marks and groove marks with every turn of one Disc alternate to make a single spiral to form a shaped track, whereby the data access ver like is improved. This procedure is called that Single spiral land / lane (SS-L / G) recording format designated. An example of a disk drive, wel This method is used in Japan the Kokai patent application no. 282669/1997.

According to the conventional disc format, Auf Drawing traces in the track direction in sectors divides and at the beginning of each sector become sector ids tification information such as the track number and the Sector number pre-formatted as wells, which a change in physical form or in generate local optical constants. Furthermore the sector format contains a first identifier ons information area in which the sector ident fiction information by a predetermined distance in the radial outward direction from the center of the Recording track are arranged offset, one second identification information area in which chem the sector identification information by one predetermined distance in the radial inward direction offset from the center of the recording track ordered and a user information area, which is the sector identification information areas succeeding and in which user information and the like in the middle of the  Recording tracks are recorded.

Next is a disk drive, which one optical disc where sector information such as explained above, arranged, used, be wrote.

Fig. 16 shows a trace pattern of the conventional optical disk. Fig. 17 shows the block diagram of the disk drive for recording or reproducing information on / from such optical disks.

Fig. 16 shows the track pattern of the conventional optical disks, the arrangement of tracks and recording sectors in one zone, and the configuration of each recording sector. As shown, the disc uses the SS-L / G recording format with the grooves and lands being the same width. This means that the width of the grooves and webs is equal to the track spacing and is half the distance between the grooves.

For a recording track that is an integer Number of recording sectors is one Sector identification information area (one sec gate identification signal part), in which sector identification information, the information for the phase rule indentation, address information and represent the like, are preformatted, at the beginning added to each sector, and user information ons area (an information recording part), in what user data and various tax information are identifiable, is the sector identification tion information part arranged below.  

In addition, the sector identification Information area two parts on, d. H. the front and rear part viewed in the scanning direction, and consists of a first identification information area in which the sector identification information tion at a predetermined distance in the radial Outward direction offset from the center of the track are ordered, and a second identification formation area in which the sector ident information by a predetermined distance in the radial inward direction from the center of the track are staggered.

An additional function is tracking compensation. For scanning optical disks, a method is known in which a pair of off-track detection pits are provided in positions offset from the center of the recording track by a predetermined distance to the right and left to detect the amount of off-track and to compensate, as shown, for example, in the standard for optical discs ISO / IFC 9171-1 , 2 "130 mm cassette for write-once optical disc for information exchange", 1990.

When the light beam passes through the middle of the pair of Lane tracking detection wells goes through, are the amplitudes of the reproduced signal of identical to the pair of acquisition wells. If the light beam is off track, the amplitude decreases of the reproduced signal from the pit to one side while the one from the recess on the other side decreases. By grasping the size the tracking of the light beam and application ner compensation it is possible to control the  Realize light beam in such a way that he goes through the middle of the track. This principle can to the SS-L / G recording format of the conventional one Drive can be applied.

It is believed that the light beam from a Be user information area (a user signal area rich) in a particular groove recording sector into a sector identification information area (a sector identification signal area) in the next groove recording sector enters. Since the Start of sector identification information area half the groove width to the outer (or inner ren) circumference of the disc is shifted, an ent speaking tracking error signal generated. After egg After a while, the light beam reaches an identifier tion signal part that by half the groove width to the inner (or outer) circumference of the disc shifted and a corresponding tracking error signal is issued. If these two error signals in Waveforms are captured that are vertically symmetrical with respect to a reference level (this is a track fol ge error level obtained when the track center is scanned), the light beam scans the Middle of the track. Accordingly, the servo controller can do so follow that the middle of the track is held by one Size comparison between tracking errors made by the identification signal parts that are detected are offset to the inner and outer circumference. Here is the order of arrangement of the first and second identification information area under different depending on whether the track is a Web or a groove. I.e. if at a web track the order of the arrangement is such that the first first identification information area comes and then the second identification information area  follows, then the order is reversed for a groove track versa.

In this way, the provision of an SS-L / G Recording disc with identification signals also to improve a servo characteristic.

Referring to FIG. 17, the configuration of the conventional disc drive is as follows. In the drawing, reference numeral 10 denotes an optical disk, 11 denotes a semiconductor laser (LD) serving as a light source, 12 denotes a collimating lens, 13 denotes a beam splitter, 14 denotes an objective lens, 15 denotes a photodetector, 16 denotes an actuator, 17 designates a differential amplifier, 18 designates a difference signal waveform shaping unit, 19 designates a processor for the reproduced difference signal, 20 designates a polarity control device, 21 designates a polarity reversing unit, 22 designates a tracking control device, 23 designates a summing amplifier, 24 designates one Sum signal waveform shaping unit, 25 denotes a processor for the reproduced signals, 26 denotes a polarity information reproduction unit, 27 denotes an address reproduction unit, 28 denotes an information reproduction unit, 29 denotes a system controller device, 30 denotes a transverse motion control device, 31 denotes a transverse motion motor, 32 denotes a recording signal processor, 33 denotes a laser driver (LD), and 34 denotes an actuator driver. The semiconductor laser 11 , the collimation lens 12 , the beam splitter 13 , the objective lens 14 , the photodetector 15 and the actuator 16 together form an optical head which is attached to a head base.

The operation of the conventional disk drive is described according to the drawing. A laser beam output from the semiconductor laser 11 is directed in parallel through the collimation lens 12 , passes through the beam splitter 13 , and is then focused onto the optical disk 10 by the objective lens 14 . The laser beam reflected from the optical disk 10 contains record tracking information and passes through the objective lens 14 and then falls over the beam splitter 13 onto the photodetector 15 . The photodetector 15 , which has two light detection parts divided along a line extending in parallel with the track in the far field formed by the reflected light to obtain a push-pull signal, and two current-voltage conversion units which form the light detection parts correspond, converts the amounts of light detected by the respective light detection parts into electrical signals and delivers the signals to the differential amplifier 17 and the summing amplifier 23, respectively.

The differential amplifier 17 generates the push-pull signal by receiving the difference between the input signals and supplies the push-pull signal to the differential signal waveform shaping unit 18 and the polarity reversing unit 21 . The differential signal waveform shaping unit 18 cuts the push-pull analog signal output from the differential amplifier 17 at an appropriate level to convert it to a digital value, and supplies the binarized differential signal to the processor 19 for the reproduced differential signal. The processor 19 determines the tracking polarity by extracting an identification signal from the binarized difference signal and supplies a polarity detection signal to the polarity control device 20 , the polarity information reproducing unit 26 , the address reproducing unit 27 and the information reproducing unit 28 .

When the polarity controller 20 receives the polarity detection signal from the reproduced difference signal processor 19 and a control signal from the system controller 29 , it supplies a polarity setting signal and a control hold signal to the polarity reversing unit 21 and the tracking controller 22 . The polarity reversal unit 21 determines , based on the control signal from the polarity control device 20 , whether the accessed track is in a web or a groove. For example, only when the track is detected as a land, the polarity of the output signal of the differential amplifier is reversed, and the output signal is then supplied to the track control device 22 as a tracking error signal. According to the level of the tracking error signal given by the polarity reversing unit 21 , the tracking control device 22 supplies a tracking control signal to the actuator driver 34 ; the actuator driver 34 supplies a drive current to the actuator 16 according to the signal and performs ei ne position control over the objective lens 14 in the direction transverse to the recording track. As a result, the light spot correctly scans the tracks.

In the summing amplifier 23 , the outputs from the photo detector 15 are added, and the summing signal is supplied to the summing signal waveform shaping unit 24 . The sum signal waveform shaping unit 24 performs a data cut of a data signal and address signals in analog form at a given threshold so that the signals receive pulse waveforms, and supplies them to the processor 25 for reproduced signals. The processor 25 outputs an identification signal containing address information and polarity information based on the binarized sum signal obtained by the waveform processing of the sum signal. The polarity information reproducing unit 26 extracts from the identification signal the polarity information which indicates the tracking polarity of the sector. The address reproducing unit 27 reproduces the sector address information from the identification information. In the information reproducing unit 28 , the binarized sum signal representing the user information recorded in the user information area on the disk is decoded and errors are corrected, and is output as a reproduced information signal. In the information reproducing unit 28 , analysis of the error correction information (e.g., the number of corrected errors and the like) obtained by the error correction or a jitter enables a data error rate to be determined. In general, the system controller 29 determines the data error rate by reading the error correction information stored in the information reproducing unit 28 and by calculating or using a table.

The polarity information output from the polarity information reproducing unit 26 and the sector address information output from the address reproducing unit 27 are sent to the system controller 29 and used for control over tracking polarity or sample and hold operation in tracking control. In the configuration under consideration, in order to intercept unwanted interference to the tracking servo system, the tracking error signal can be sampled and held just before the sector identification information areas, and the tracking control can be excluded while the light beam is cutting the sector identification information areas tracked. The system controller 29 into which information regarding the identification signals from the reproduced difference signal processor 19 , the polarity information reproducing unit 26 and the address reproducing unit 27 are inputted, provides control signals to the polarity controller 20 , the lateral motion controller 30 , the LD driver 33 and the processor 32 for recorded signals.

The system control device 29 determines whether the light beam is at a desired address based on the information about the identification signals including addresses from the address reproducing unit 27 and the like. The traverse control device 30 moves the optical head to a target track by supplying a driving current to the traverse motor 31 in accordance with the control signal from the system control device 29 . At the same time, the tracking controller 22 interrupts the tracking control operation by the control signal from the system controller 29 . In normal playback, the system control device 29 drives the cross-motion motor 31 via the cross-motion control device 30 in accordance with the tracking error signal input from the tracking control device 22 and gradually moves the optical head in the radial direction together with the playback.

In the processor 32 for recording signals, the error correction code is added to the recording data input when recording, and the encoded recording signal obtained by adding the error correction code is supplied to the LD driver 33 . When the system control device 29, the LD driver 33 by using the offset control signal in the recording operation, the LD driver 33 modulates the supplied to the semiconductor laser 11 drive current corresponding to the recording signal. The intensity of the light spot radiated onto the optical disk 10 is varied in accordance with the recording signal and recording recesses are thereby formed. On the one hand, when the LD driver 33 is reproduced by the control signal from the system control device 29, it is put into the playback mode and controls the driver current in such a way that the semiconductor laser 11 imitates light with a constant intensity. In this way, it is possible to detect recording pits and prepits on the recording tracks.

With the conventional disc drive with the vorbe written configuration will track errors an optical disk with guide grooves, such as one SS-S / G recording disc, usually by that Push-pull method recorded. However, it is known that this method is in principle covered with a Tracking error signal is connected, which is a wel len shape, which is vertically asymmetrical Lich a reference level (hereinafter an optical Referred to) due to an inclination,  even if the light beam scans the middle of the track. That is, the effect of the tilt is equivalent to egg ner superimposition of an electrical displacement the tracking error signal.

If the optical offset is processed by considered it the same as electrical displacement will, d. H. if a dislocation which is the optical Dislocation makes electrical for the compen is superimposed, the light beam runs out of the Lane center (a lane departure state), and the zu reliability of signal acquisition is reduced. In particular, the quality of the signal is ver deteriorated (lower signal-to-noise ratio) due to a Cross erasure between neighboring tracks at the Recording, a bad deletion when over write a crosstalk from a neighboring one Track during playback and the like. Beyond that the quality of a reproduced signal worsened by an inclination optical aberration. These problems could be an indication dernis for the reduction of the track spacing as a Means to improve the recording density.

To solve these problems, a conventional one is used Disc drive a process in which the Track deviation is compensated for by using the Disc format in which the sector ident ons information in a graded manner in the Outward and inward direction with respect to the middle of the track are arranged at a certain distance. By the procedure is compensated for the lane deviation that the absolute value of the difference between the Tracking error signal and the reference level (the level of the tracking error signal which occurs when the Track center was obtained) when the first identification information  are reproduced, and the absolute value of the difference between the tracking Error signal and the reference level when the second Identification information is reproduced, are the same. The procedure is effective when the Lane deviation is caused by only one cause.

However, in the drive used in practice ben other causes of vertically asymmetric track follow error signals, for example transfers to electrical circuits (hereinafter referred to as electri cal dislocations to distinguish them from the opti called dislocations), lack of reinforcement compensation of an optical system or electri shear circuits or the like. In a wide These are interpreted as the tracking error considered overlays.

This is where the conventional disc drive comes in the problem of an inclination and lane departure cannot be optimally compensated for on the Basis of only one reflected light from one Disc. For this reason, it is considered a process for Compensating slopes an optical slope end tector is also provided on the optical head and used. Through this procedure is while only inclinations can be compensated separately, the Optical tilt detector additionally required. Hence the problem of an inevitable increase the cost of the drive.

As another method of compensating for Nei conditions without the optical tilt detector Using a combination of a conventional one Lane departure index and other indexes, such as a Tremors and the playback error rate of a played  Signals and the like can be viewed.

However, the problem with this method is that the tilt and lane deviation compensation is not can be merged or a long time need for the merge because of an inclination compensation by repeated estimation under Ver multiple parameters is required because the Tremors and the error rate depend on both the slope as well as the track deviation change.

In addition, procedures have been developed which are new Apply signal processing method, studied. With in other words, procedures have been studied through which the detected error rate is lower than at the previous procedure. One of these is the maximum probability estimate, e.g. B. the Viterbi acquisition, which is called an acquisition process is known which is stronger against a deterioration The quality of signals protects as one Conventional, bit-by-bit detection. the However, this procedure requires the addition of a new configuration to the conventional signal acquisition system, and an increase in the cost of the acquisition drive is thereby inevitable.

DE 196 49 970 A1 discloses a drive device device for an optical disk as described above, in which an Ab tactile light point is generated.

US 5675564 A also shows a drive direction for an optical disc. When reading one Optical plate is compensated for Inclination between a readhead and the scan the disc. The scanning beam from the Scanning head is generated in several partial beams split. The part reflected by the disc rays are detected with separate photodetectors and then processed. The slope compensation on is due to a tilt sensor emitted and detected measuring light beam.

The present invention is based on the object de to create a disc drive, which Nei can compensate without increasing the Ko Most of the drive, and the only separated inclinations oh ne an influence of the tracking error compensation can compensate.

According to the invention, the disk drive for Compensate for the slope between a disc holding a first identification information item rich, the radially outward by a predetermined Distance is shifted from the center of a track, and a second identification information area, the shifted radially inwards by the same distance and a head to form a light spot the disc, a photodetector for receiving light reflected from the point of light, a device for determining a sum signal from an output signal from the photodetector obtained when the Spot of light the first identification information item rich and an output signal that he when the point of light held the second identi fication information area, and a Tilt control device for using the sum signals as an index to control the relative Inclination between the disc and the head to be cause the index to approach an extreme value hert.  

According to the invention, the disk drive uses a Sum signal from a Sun signal amplitude of that Photo detector that is obtained when the point of light ver the first identification information area follows, and a sum signal amplitude obtained when the point of light has the second identification Information area is tracked as an index.

According to the invention, the disk drive uses a Sum signal from a difference signal amplitude of the photodetector that is obtained when the light point the first identification information point tracked, and a differential signal amplitude that he will hold when the point of light the second Identi fiction information area is tracked as the index.

According to the invention, the disk drive uses a Sum signal from an absolute value of a difference  between an envelope of a differential signal of the photodetector that is obtained when the light point the first identification information area tracked, and a reference level, and an absolute value from a difference between a wrapping egg nes difference signal obtained when the Light point the second identification information richly tracked, and a reference level, as the index.

According to the invention, the disk drive for Compensate for the slope between a disc holding a first identification information item rich, the radially outward by a predetermined Distance is shifted from the center of a track, and a second identification information area, the shifted radially inwards by the same distance, and a head for forming a light spot on the Disk, a photo detector for detecting on the Point of light reflected light, a device for Determine a difference signal or an absolute one Value of the difference signal of an output signal from the photodetector that is obtained when the light point the first identification information area tracked, and an output signal received when the point of light has the second identification ons information area traced, and an inclination Control device for using the difference signal or an absolute value of the difference signal as an index to determine the relative slope between the Control disc and head so that it is close The index is brought to an extreme value.

According to the invention, the disk drive uses a Difference signal or an absolute value of the dif renzsignal from an envelope of the difference signal from the photodetector obtained when the  Spot of light the first identification information item richly pursued, and wrapping a difference signals that is obtained when the light spot reaches the pursues second identification information area, than the index.

The invention is described below with reference to FIGS guren illustrated embodiments be wrote. Show it:

Fig. 1 is a block diagram of a disc drive according to the first embodiment of the invention;

Fig. 2 is a block diagram of the Systemsteuervorrich processing according to FIG. 1,

, The drive for the first game Ausführungsbei form Fig. 3A to 3I waveforms, which are output from blocks the discs,

Fig. 4 is a block diagram of a first waveform shaping unit which forms the disk drive according to the first embodiment,

Figure 5 is a flow chart for execution. With respect to the process for the determination of the first index from the first,

FIG. 6A to 6D, the relationship between each index and the size of the inclination in each of the embodiment according to the invention,

Fig. 7 is a flow chart showing the process of supply compensation Nei example shows the first execution,

Fig. 8 is a block diagram of a disc drive according to the second embodiment of the invention;

9 is a block diagram of a second wave form shaping unit, which drove the Scheibenan forms. According to the second embodiment,

That the ticket benantrieb after the second exporting approximately example form FIG. 10A to 10K waveforms are given by blocks of,

Fig. 11 is a flow chart showing the procedure for loading agree example shows the second index at the execution,

Fig. 12 is a flow chart showing the process of loading humor of the third index in a Abwand development of the second embodiment shows

Fig. 13 is a flow diagram conversion is another method for determining the third index in the Ab shows the second embodiment,

Fig. 14 is a block diagram of a disc drive according to the third embodiment of the invention,

Fig. 15 is a block diagram forms a third wave form shaping unit, which drove the Scheibenan according to the third embodiment,

Fig. 16 shows a track pattern of a conventional optical disc rule, and

Fig. 17 is a block diagram of a conventional disk drive.

Embodiment 1

A detailed description of blocks having an identical designation as in the prior art is omitted because these blocks are basically the same as those in the disk drive shown in FIG. 17.

Fig. 1 shows the block diagram of a disc drive according to the first embodiment of the inven tion. In the drawing, reference numeral 10 denotes an optical disk, 11 denotes a semiconductor laser (LD) serving as a light source, 12 denotes a collimating lens, 13 denotes a beam splitter, 14 denotes an objective lens, 15 denotes a photodetector, 16 denotes a Actuator, 17 denotes a differential amplifier, 18 denotes a differential signal waveform shaping unit, 19 denotes a processor for a reproduced difference signal, 20 denotes a polarity control device, 21 denotes a polarity reversing unit, 22 denotes a tracking control device, 23 denotes a summing amplifier , 25 denotes a reproduced signal processor, 26 denotes a polarity information reproducing unit, 27 denotes an address reproducing unit, 28 denotes an information reproducing unit, 30 denotes a transverse motion control device, 31 denotes a transverse motion motor , 32 denotes a recording signal processor, 33 denotes a laser driver (LD), and 34 denotes an actuator driver. Their functions are the same or equivalent to those in the prior art. The semiconductor laser 11 , the collimation lens 12 , the beam splitter 13 , the objective lens 14 , the photodetector 15 and the actuator 16 together form an optical head which is attached to a head base.

In addition, 100 denotes a first waveform Molding unit, 101 denotes a system control direction and 102 denotes a tilt control device direction.

As illustrated in Fig. 2, the system includes control device 101 includes a processor such as a digi tal signal processor (DSPI 101a and a program memory 101 b, and operates according to the program memory in the Pro 101 b stored programs. The Sy stemsteuervorrichtung 101 comprises also an analog / digital converter (ADC) 101 c and a digital / analog converter (DAC) 101 d, which perform an analog / digital and digital / analog conversion when analog signals are input or output ,

The operation in the reproduction of the optical disk shown in FIG. 16 through the disk drive according to the embodiment with the configuration described above is explained with reference to FIG. 1 and FIGS . 3A to 31, which waveforms of the respective units in FIG. 1.

A laser beam output from the semiconductor laser 11 is directed in parallel through the collimation lens 12 , passes through the beam splitter 13 and is then focused through the objective lens 14 onto the optical disc 10 . The laser beam reflected by the optical disk 10 contains recording track information and passes through the lens lens 14 and is then directed by the beam splitter 13 onto the photodetector 15 . The photo detector 15 , which has two light detection parts which are divided along a line which extends parallel to the track in the far field formed by the reflected light to obtain a push-pull signal, and two current / voltage conversion units which correspond to the light detection parts, has, converts the light quantities received by the respective light detection parts into electrical signals and delivers the signals to the differential amplifier 17 and the summing amplifier 23 .

The differential amplifier 17 generates a push-pull signal indicated by (a) in FIG. 3A, in which the difference between the input signals is obtained, and supplies the push-pull signal to the differential signal waveform shaping unit 18 and the polarity reversing unit 21 . The differential signal waveform shaping unit 18 intersects the analog push-pull signal output from the differential amplifier 17 at two suitable levels (TH1, TH2) to convert the push-pull signal into digital values, which are shown as (d) and (e) in Figs. 3B and Fig . 3C are shown, and supplies the binarized difference signals to the processor 19 for reproduced differential signals. Waveform (d) indicates the position of the first identification information area, and (e) indicates the position of the second identification information area. The reproduced difference signal processor 19 determines the tracking polarity from the times when the binarized difference signals (d) and (e) appear, and supplies a polarity detection signal to the polarity control device 20 , the polarity information reproducing unit 26 , the address reproducing unit 27 , the information reproducing unit 28 and the system control device 101 . Additionally, the processor 19 provides as (d) and (e) in Fig. 3B and Fig for reproduced differential signals. Shown digital values to the system controller 101 3C.

Upon receipt of the polarity detection signal from the reproduced difference signal processor 19 and a control signal from the system controller 101 , the polarity controller 20 supplies a polarity setting signal to the polarity reversing unit 21 and a control hold signal for erroneous control to the tracking controller 22 . According to the polarity setting signal from the polarity control device 20 , the polarity reversing unit 21 supplies the output signal of the differential amplifier 17 as the tracking error signal to the tracking control device 22 , the polarity being reversed only when the accessed track is, for example, in a web. According to the level of the tracking error signal from the polarity reversing unit 21, the tracking controller 22 supplies a tracking control signal to the actuator driver 34 ; the actuator driver 34 supplies a drive current to the actuator 16 according to this signal and performs position control via the objective lens 14 in the transverse direction to the recording track. As a result, the point of light scans the tracks correctly by the track sequencer.

In the summing amplifier 23 , the outputs of the photo detector 15 are added, and the sum signal shown as (h) in FIG. 3F is supplied to the first waveform shaping unit 100 . The first waveform shaping unit 100 performs certain processing on the analog sum signal and then slicers at a given threshold to generate and provides a pulse waveform shown as (k) in FIG. 31 to the playback signal processor 25 . The operations following the reproduced signal processor 25 are the same as in the prior art, so their description is omitted.

The configuration and operation of the first waveform shaping unit 100 will be described with reference to FIG. 4. In the drawing, reference numeral 200 designates a first attenuator (ATT), 201 designates a DC control device, 202 designates an automatic gain control unit (AGC), 203 designates a waveform generator, 204 designates a signal cutting device, and 205 designates a first envelope / signal amplification -Detector.

The reproduction level of the sum signal shown as (h) in FIG. 3F and input from the summing amplifier 23 is set by a certain gain in the first ATT 200 . The gain of the first ATT 200 is set by a control signal from the system controller 101 . That is, the system controller 101 determines the optimal gain setting of the first ATT 200 according to the amplitude information of an output signal of the first ATT 200 . The magnitude of the gain is adjusted in the first ATT 200 so that an adequate detection resolution of the first cladding / signal amplitude detector 205 is obtained and the quality of the reproduced signals is maintained in the units following the DC control device 201 .

The sum signal, the gain of which has been set by the first ATT 200 , is input to the DC controller 201 , in which the DC component is removed, so that the waveform as shown as (j) in Fig. 3H. The DC control device 201 removes the DC components which are not necessary for data reproduction in order to be able to take full advantage of the dynamic range of the AGC 202 in the subsequent stage. However, in an area in which the DC component changes abruptly, such as a boundary between the sector identification information area and the user information area, and in an area in which signals are discontinuous, a large sag occurs in the output signal of the DC control device 201 on. Accordingly, the DC controller 201 has the functions of reducing time constants for eliminating the DC component by boost control gate signals shown as (g) in FIG. 3E and input from the system controller 101 , and temporarily collecting the DC change in the input signal. The lifting control gate signal is a pulse with a predetermined time width generated by the system controller 101 . The Anhebungssteuer- gate signal rises at the starting points of the first and second identification information area, the signals shown as the top edges of the respective in (d) and (e) in Fig. 3B and Fig. 3C shows which of the processor 19 for reproduced differential signals and at the start and end points of the user information area, which are indicated as a start edge or end edge of the signal shown as (f) in Fig. 3D, which corresponds to the address signal contained in the sector identification information area (as shown in the address reproducing unit 27 ) he is caught. In addition, when the DC level fluctuates due to errors and the like, by outputting the boost control gate signal from the time when the defective area ends, the time delay until the data is normally acquired after the termination of the error can be reduced ,

The waveform (j) of the output signal of the DC controller 201 is finely adjusted in the AGC unit 202 to obtain a predetermined signal amplitude. The AGC unit 202 forms a feedback control system which monitors the signal amplitude of the input signal and controls its own gain to keep the level of the output signal at a predetermined amplitude. Accordingly, the amplitude information about the input signal, ie the output signal of the first ATT 200 , is extracted from the AGC unit 202 .

The output signal of the AGC unit 202 is fed to the waveform equalizer 203 , in which waveform distortion caused by the frequency response of the optical system is reduced, and then binarized in the signal cutter 204 , as shown by (k) in Fig. 31, and then LOVED fert to the reproduction signal processor 25th Optimal adaptive control is performed on the cutting level of the signal cutting device 204 to minimize playback errors. In addition, the signal cutting device 204, like the DC control device 201, has an increasing function to decrease the time constant for the cutting level control according to the raising control gate signal from the system control device 101 and to follow the fluctuations of the input signal in a short time.

In the first envelope signal amplitude detector 205 , the envelope of the upper and lower sides of the output signal of the first ATT 200 and the signal amplitude are detected and then supplied to the system controller 101 ((i) in FIG. 3G). These signals are used as indexes for the tilt compensation, as will be described later.

In the operations described so far, tilt compensation is not performed, so the quality of the reproduced signal, that is, the reliability of the data to which error correction has been applied, cannot be acceptable. For this reason, it is desirable, immediately after the adjustment of the optical disk 10 , or when the reliability of the reproduced data has deteriorated due to the change over time, that the tilt compensation is performed to maintain an appropriate operating distance of the drive and improve the reliability of the reproduced data. The quality of the signal can be determined if the jitter of the signal binarized in the signal cutter 204 or the number of error corrections (the data error rate) determined as a result of the processing of the information reproducing unit 28 in the subsequent stage, to which System control device 101 performed and processed in this by calculation or with reference to a table.

A feature of the present embodiment is that the sum of the amplitude of the signal, which is output from the summing amplifier 23 during the reproduction of the first identification information area, which forms the sector identification information area, and the amplitude of the signal, which is output from the summing amplifier 23 during reproduction from the second identification information area, which also forms the sector identification information area, as an index (hereinafter referred to as a first index) for determining the amount of inclination between the optical disk and the optical head is used. That is, the first index is stemsteuervorrichtung from the Sy 101 determined by operations performed on the of the first sheath / signal amplitude detector 205 signal amplitude information received, the in the system control device 101 provided for the analog / digital converter 101 c during playback of the first and the second identification information area is used.

That is, the system control device 101 receives the output signal of the first envelope / signal amplitude detector 205 in the waveform shaping circuit 100 and converts the received output signal by means of the analog / digital converter 101 c into digital signals and determines the index in which the operation shown in Fig. 5 is performed.

That is, the system controller 101 waits until a time point T1 when the information from the first identification information area is reproduced (S21) and samples the output of the first envelope / signal amplitude detector 205 and collects this sample as SH1 in the processor 101 a (S21). The system controller 101 then waits until a time T2 at which the information from the second identification information area is reproduced (S23) and samples the output signal of the first envelope / signal amplitude detector 205 and collects this sample as SH2 in the processor 101 a (S24). The system controller 101 then determines the sum SHs = SH1 + SH2 and sets the value of the sum SHs as the first index (S25).

Alternatively, it is possible to provide the first cladding / signal amplitude detector 205 with two sampling and holding circuits and an operational amplifier for generating an analog sum signal. In this case, the first index is obtained when the generated sum signal is led to the analog / digital converter 101 c or the like in the system control device 101 . However, it is necessary to add a signal line to provide the first envelope / signal amplitude detector 205 with a control signal for controlling the sample and hold operation. Furthermore, the first index can also alternatively be determined by performing an operation on the amplitude information supplied from the AGC unit 202 to the analog / digital converter 101c , since the signal amplitude information can also be obtained from the AGC unit 202 , such as is prescribed.

Since, as described above, the signal amplitude information can be obtained from the first cladding signal amplitude detector 205 or the AGC unit 202 which is already present in the driver device for acquiring data from the reproduced signal no new circuitry is required and the cost of the driver device is not increased. In this way, the index for determining the tilt compensation amount used to bring the relative tilt between the optical disk and the optical head to substantially zero can be by the first cladding / signal amplitude detector 205 or the AGC unit 202 and the system controller 101 he will keep.

In Fig. 6A, the measured relationship between the determined first index and an inclination of the optical rule head in the radial direction of the optical disc is applied (a radial skew). As the drawing indicates, the tilt between the optical disk and the optical head can be approached to zero when the tilt control device 102 is controlled so that the first index approaches the extreme value (the peak). This relationship can be approximated by a negative quadratic function with a peak at a point where the radial slope is essentially zero. In the drawing the degree of dependence on the size of the track deviation is shown by a vertical line for each measured value. It can be seen from the drawing that the vertical lines are short and the first index changes only depending on the size of the slope and hardly on the size of the track deviation. In Fig. 6, a data clock, which is normalized by the period of the reproduced clock, is between the reproduced data and the reproduced clock, which is synchronized with the reproduced data generated in a data phase locked loop, against the radial inclination plotted. The drawing shows that the jitter of the reproduced signal changes so that it is close to the minimum value when the tilt control device is controlled so that the first index approaches an extreme value. That is, the first index is effective for tilt compensation.

In the slope compensation process, the size the first index obtained for each sector and the compared to the previous first index received, so that the compensation is done for each sector becomes. In this case, the could be based on that of the Sector identification information area The first signal generated an anomalous signal Have value due to a defect in a sector or similar. To stop the influence if the slope compensation for each sector a threshold value can be set to one agreed value for the range of variation of the first In dex as a unit for a compensation step can be set and it can be controlled that if the range of variation of the first index is the Threshold exceeds the index not for the Inclination compensation is used. Instead of The slope compensation for each sector can Compensation can also be done by an on number of sectors is taken as a unit  by using the average of the first Index made up of such a number of sectors was holding. In this case, compared to the case in which the compensation for each sec tor is carried out, the disadvantage that the changes first index for each sector decreased can be and a burden on the slope compensation on system can also be reduced.

In this way, satisfactory tilt compensation is obtained when the system controller 101 controls the tilt control device 102 such that the amount of the tilt compensation is set to a value at which the first index is the maximum. The incline compensation device is formed by the system control device 101 and the incline control device 102 . In general, the tilt compensation mechanism is mounted on a mechanical base on which an optical head and the transverse motion motor are arranged. A more detailed description thereof is omitted.

By selecting a pattern that is often continuous This is often done as a playback data pattern for Obtaining the first index it is possible to get the signal amplitude with stability and high accuracy believe it. The best pattern is the VFO- (Variable Fre quenzoszillator) pattern for the data phase rule Circle synchronization, which opened before the data draws or is preformatted. The position of the VFO area is usually by sector format defined and the signal amplitude can be correct at a certain point in time, so that the Accuracy and reliability of the tilt compensation tion are improved.  

In the case of a disk with a land / groove recording format shown in FIG. 16, the reliability of data acquisition can be improved by setting the inclination compensation for lands and grooves separately. This can be done by storing the respective optimal parameters for lands and grooves obtained during the compensation process in a table and by the system controller 101 controlling the drive with respect to the table. Alternatively, if the setting between the webs and grooves is not changed, it may not be possible to set the parameters for the respective optimal values. In this case, the parameters can be set so that the quality of reproduced signals (in a broad sense, including jitter and the error rate of reproduced data) of lands and grooves is within an allowable range.

Next, an inclination compensation method for the disk drive according to the invention will be described with reference to FIG. 7. If power is supplied to the drive and the optical disc is placed on it, the drive enters the start state (S2). Then, the system controller 101 initializes parameters for the entire drive (S2). The electrical offset in analog circuits for generating focusing error signals and tracking error signals is compensated (S3). Next, the optical disk 10 is rotated (S4), the LD 11 is turned on (S5), and a focus pull-in operation is performed (S6). The gain balance in the optical system and the electrical circuit system is compensated (S7), and then a tracking pull-in operation is performed (S8). When the tracking feed is reached and preparation for playback is finished, the tilt compensation process is started.

First, an index of the inclination, which is the first index here, is measured (S9), and it is determined whether the result of the measurement is within an allowable range or not (S10). That is, a determination is made as to whether the first index is within the range of permissible values which contains extremes. If the first index is out of range, the tilt controller 102 is instructed and controlled by the system controller 101 to change the amount of tilt compensation (S11), and then the operations after step S9 are repeated. When the first index is within the range, the process is ended and the standby state continues until the next command (S12).

In the embodiment, while the Nei compensation is described in the slices powered electrical transfers, an inequality in the optical system, dislocations due to Ver strength inequality in the detection circuit, so like dislocations caused by the track deviation be effective. The following three steps are followed applies to the above-mentioned transfers exactly compensate: First, the electrical offset tongues, the imbalance in the optical system and caused by the gain inequality in the detection caused switching dislocations compensated. Second, the slope is compensated accordingly the variable index, which only depends on the size of the Inclination depends and not on the size of the track softening depends. Last is the lane departure  compensated.

Embodiment 2

Fig. 8 shows a block diagram of a disc drive according to the second embodiment of the invention. In the drawing, reference numeral 10 denotes an optical disk, 11 denotes a semiconductor laser (LD) serving as a light source, 12 denotes a collimating lens, 13 denotes a beam splitter, 14 denotes an objective lens, 15 denotes a photodetector, 16 denotes a Actuator, 17 denotes a differential amplifier, 18 denotes a differential signal waveform shaping unit, 19 denotes a processor for reproduced differential signals, 20 denotes a polarity control device, 21 denotes a polarity reversing unit, 22 denotes a tracking control device, 23 denotes a summing amplifier, 25 denotes a reproduction signal processor, 26 denotes a polarity information reproduction unit, 27 denotes an address reproduction unit, 28 denotes an information reproduction unit, 30 denotes a transverse motion control device, 31 denotes a transverse motion motor, 32 denotes e A recording signal processor, 33 denotes a laser driver (LD) and 34 denotes an actuator driver. Their functions are the same or equivalent to those described in connection with the prior art example or the first embodiment. The semiconductor laser 11 , the collimation lens 12 , the beam splitter 13 , the objective lens 14 , the photodetector 15 and the actuator 16 together form an optical head which is attached to a head base.

In addition, 100 denotes a first waveform shaping unit, 101 denotes a system control device, and 102 denotes an inclination control device. The blocks mentioned above are identical to the blocks of FIG. 1, which was explained in connection with the first embodiment, and their operation is also basically identical. A block, not shown in FIG. 1, is a second waveform shaping unit 103 , the details of which are shown in FIG. 9. In the drawing, reference numeral 206 denotes a second attenuator (ATT), and 207 denotes a second cladding / signal amplitude detector. Only those input and output signals from the system controller 101 that relate to the second ATT 206 and second envelope / signal amplitude detector 207 are illustrated.

The operation will be described next. The However, description is limited to the difference to embodiment 1.

In the present embodiment, an index for tilt compensation is obtained from a push-pull signal, which is shown as (a) in FIG. 10A and is output from the differential amplifier 17 . Ge said more precisely, the sum of the amplitude was the currency rend the reproduction of the first Identifikationsinfor mationsbereichs that forms the sector identification information area, receive an output from the differential amplifier 17 signal and the amplitude of an out by the differential amplifier 17 added signal during reproduction from the second identification information area, which also forms the sector identification information area, is used as the index (hereinafter referred to as a second index). The rest of the workflow is similar to that of the first embodiment.

The detection of the second index is started when the system controller 101 controls the second ATT 206 to adjust the level of the output signal of the ATT 206 so that the amplitude of the signal can be detected with a high accuracy by the second envelope / signal amplitude detector 107 , The system controller 101 determines the second index, by performing deninformation operations with the Signalamplitu obtained during playback of the first and second Identifikationsinformati onsbereichs, wherein the was in the system controller provided for the analog / digital converter 101 c used according to the as (c) signal amplitude detection waveform shown in FIG. 10C output from the second cladding / signal amplitude detector 207 .

That is, the system control device 101 receives the output signal of the second envelope / signal amplitude detector 207 and converts the received output signal into digital signals by means of the analog / digital converter 101 c, and determines the index in which the operation shown in FIG. 11 is carried out becomes. That is, the system controller 101 was tet until a time T1 at which the infor mation is reproduced ranging from the first Identifikationsinformationsbe (S31), the output samples signal (c) of the second sheath / signal amplitude detector 207 and collects this sample as SH1 in the processor 101 a (S32). The system control device 101 then waits until a point in time T2 at which the information from the second identification information area is reproduced (S33), detects the output signal (c) of the second envelope / signal amplitude detector 107 and collects this sample value as SH2 in the processor 101 a (S34). The system controller 101 then determines the sum SHs = SH1 + SH2 and sets the value of the sum SHs as the second index (S35).

As an alternative, it is possible to provide two sample and hold circuits and an operational amplifier in the second envelope / signal amplitude detector 207 in order to generate an analog sum signal. In this case, the system controller 101 may only by taking the sum signal generated using the analog / digital converter 101 c, or the same will receive the second index without performing any operations. However, it is necessary to add a signal line to provide the second cladding / signal amplitude detector 207 with a control signal for controlling the sample and hold operation. The second index changes only depending on the slope size and not the size of the lane deviation, as the first index does. The measured relationship between the determined second index and a radial inclination is plotted in FIG. 6B. As indicated in the drawing, the relative tilt between the optical disc and the optical head can be approached to zero when the tilt controller 102 is controlled so that the second index approaches the maximum (peak). The relationship can be approximated by a negative quadratic function which has a peak at a point where the radial slope is substantially zero. In the drawing, the degree of dependence on the lane departure amount is shown by a vertical line for each measured value. It can be seen from the drawing that the vertical lines are short and the second index changes only in dependence on the size of the slope and hardly on the track deviation size. In addition, as shown in Fig. 6D, a data clock period between the reproduced signal and the reproduced clock changes so that it is close to the minimum value when the tilt controller is controlled so that the second index becomes an extreme value approaches. That is, the second index is effective for tilt compensation. In this way, it is satisfactory with respect to the tilt compensation according to the present embodiment, when the system control device 101 controls the tilt control device 102 in such a manner that the amount of the tilt compensation is set to a value at which the second index is the maximum , The method of tilt compensation is similar to the method described in connection with the first embodiment.

By selecting a pattern that is often continuous ier occurs as a reproduced data pattern to detect the signal amplitude, it is possible to Signal amplitude stable and with high accuracy to capture. The best pattern is the VFO pattern for the Data phase locked loop synchronization, which before the data is recorded or preformatted, as in connection with the first execution game was explained.

The index obtained from the push-pull signal, which is an output signal of the differential amplifier 17 shown as (a) in Fig. 10A, may alternatively be from the absolute value ((b) in Fig. 10B) of the difference between the envelope of the push-pull signal and a reference level can be derived. In Fig. 10B, the signal level outside the sector identification information areas is shown to be zero. But this is not necessarily the case. When the output signal of the differential amplifier 17 is different from the reference level outside of the sector identification information areas due to track deviation, electrical offset or the like, the signal level of the signal (b) shown in Fig. 10B is not zero. The tilt compensation index may obtain the sum of the absolute value ((b) in FIG. 10B) of the difference between the envelope of the push-pull signal, which is an output signal from the differential amplifier 17 , during reproduction of the first identification information area, and the reference level, and the absolute value ((b) in FIG. 10B) of the difference between the envelope of the push-pull signal obtained during reproduction of the second identification information area and the reference level (this index is referred to as the third index).

In other words, the absolute value of the difference between the envelope of the push-pull signal, which is an output signal from the differential amplifier 17 , obtained during the reproduction of the first identification signal area and the envelope of the gene-clock signal obtained during the reproduction of the second identification signal area , can be determined. The third index may alternatively be the difference between the wrapping of the counter clock signal, which is an output signal of the differential amplifier 17 , which was obtained during the reproduction of the first identification information area, and the wrapping of the push-pull signal, which was during the reproduction of the second identification information area was obtained. However, it is necessary to state that the polarity of the third index is different between the land part and the groove part.

In the foregoing description, it is assumed that the envelope on the side near the reference level (ie, the level obtained during the reproduction of the space part between the recess parts) is detected. As an alternative, the envelope on the side farther from the reference level (ie, the level obtained during reproduction of the depression part) can be detected. The reference level may be the DC level of the output signal of the differential amplifier 17 obtained when the light beam scans the center of the track, outside the sector identification information areas.

The sequence for determining the third index is shown in FIG. 12. First, the system controller 101 waits until a time T0 at which the information from an area outside the sector identification information areas is reproduced (S41), samples the output signal (b) of the second envelope / signal amplitude detector 207 , and collects this sample as SH0 (S42). The system controller 101 then waits until a time T1 at which the information from the first identification information area is reproduced (S43), samples the output signal (b) of the second envelope / signal amplitude detector 207 and collects this sample as SH1 (S44). The system controller 101 then waits until a point in time T2 at which the information from the second identification information area (S45) is reproduced, samples the output signal (b) of the second envelope / signal amplitude detector 207 and collects this sample as SH2 ( S46). The system controller 101 then determines the sum

SHs = | SH1 - SH0 | + | SH2 - SH0
and sets the value of the sum SHs as the third index (S47).

Another alternative sequence for determining the third index is shown in FIG. 13. That is, The system controller 101 then waits until a time T1 at which the information from the first identification information area is reproduced (S51), samples the output signal (b) of the second envelope / signal amplitude detector 207 and collects this sample as SH1 ( S52). The system controller 101 then waits until a time point T2 at which the information from the second identification information area is reproduced (S53), samples the output signal (b) of the second envelope / signal amplitude detector 207 and collects this sample as SH2 (S54). The system controller 101 then determines the difference

SHs = | SH1 - SH2
and sets the value of the difference SHs as the third index (S55). Alternatively, the difference

SHs = SH1 - SH2

determined and used as the third index.

In Fig. 6C, measured relationship between the determined third index and a radial inclination is plotted. As the drawing indicates, the relative tilt between the optical disc and the optical head can be approached to zero if the tilt control device 102 is controlled so that the third index approaches the maximum (peak). The relationship can be approximated by a negative quadratic function that has a peak at a point where the radial slope is substantially zero. In the drawing the degree of dependence on the size of the track deviation is shown by a vertical line for each measured value. It can be seen from the drawing that the vertical lines are short and the third index changes only in dependence on the size of the inclination and hardly on the size of the track deviation. However, as shown in Fig. 6D, a data clock jitter between a reproduced signal and the reproduced clock changes so that it is close to the minimum value when the tilt controller is controlled so that the third index approaches an extreme value. This means that the third index is effective for tilt compensation. Thus, in the tilt compensation according to the present embodiment, it is satisfactory if the system control device 101 controls the tilt control device 102 in such a manner that the amount of the tilt compensation is set to a value at which the third index is the maximum. The method of tilt compensation in this case is similar to the method described in connection with the first embodiment.

By selecting a pattern that is often continuous ier occurs as a reproduced data pattern to enclose the wrapper, it is possible to wrap the wrapper tion of the reproduced signal stable and with high Frequency. The best pattern is that  VFO (variable frequency oscillator) pattern for the Data phase locked loop synchronization, which as in the description above before the dates draws or is preformatted.

In the present example, the second ATT 206 and the second envelope / signal amplitude detector 207 must be added for detection of the signal amplitude information or envelope. However, the first ATT 200 and the first cladding / signal amplitude detector 205 , which are already provided in the drive for acquiring data from reproduced signals, may be the same circuits as these. As a result, no new circuits are required and the cost of the drive is hardly increased.

As described, the index for adjusting the amount of tilt compensation can be determined by the second envelope / signal amplitude detector 207 and the system controller 101 . A tilt compensation device can be formed by the system control device 101 and the tilt control device 102 .

Embodiment 3

Fig. 14 is a block diagram showing a disk drive according to the third embodiment of the inven tion. In the drawing, reference numeral 10 denotes an optical disk, 11 denotes a semiconductor laser (LD) serving as a light source, 12 denotes a collimating lens, 13 denotes a beam splitter, 14 denotes an objective lens, 15 denotes a photo detector, 16 denotes an actuator , 17 denotes a differential amplifier, 18 denotes a differential signal waveform shaping unit, 19 denotes a processor for reproduced differential signals, 20 denotes a polarity control device, 21 denotes a polarity reversing unit, 22 denotes a tracking controller, 23 denotes a summing amplifier, 25 denotes a reproduced signal processor, 26 denotes a polarity information reproducing unit, 27 denotes an address reproducing unit, 28 denotes an information reproducing unit, 30 denotes a transverse motion control device, 31 denotes a transverse motion motor, 32 denotes one Record signal processor, 33 denotes a laser driver (LD) and 34 denotes an actuator driver. Their operations are the same or equivalent to those described in the prior art. The semiconductor laser 11 , the collimation lens 12 , the beam splitter 13 , the objective lens 14 , the photodetector 15 and the actuator 16 together form an op table head which is attached to a head base.

In addition, 101 denotes a system control device and 102 denotes a tilt control device. The blocks mentioned above are identical to those of Fig. 1, which were described in connection with the first embodiment. The operations of these are also identical.

FIG. 15 is a block diagram showing the details of a third waveform shaping unit 104 , which is the block not shown in FIG. 1, and the details of the system controller 101 used in this embodiment. In the drawing, reference numeral 200 designates a first ATT, 201 designates a DC control device, 202 designates an AGC unit, 203 designates a waveform equalizer, 204 designates a signal cutter, 205 designates a first envelope / signal amplitude detector, 206 designates a second ATT, 207 denotes a second envelope / signal amplitude detector and 208 denotes a signal selection device which selects either the output signal of the first ATT 200 or the output signal of the second ATT 206 and supplies the selected output signal to the DC control device 201 . The blocks of reference numerals 200 to 204 are identical to those in FIG. 4, which was described in connection with the first embodiment. The blocks of reference numerals 206 and 207 are identical to those of FIG. 9, which was described in connection with the second embodiment. Your operations are basically the same.

The system control device 101 includes a first index determination device 211 , a second index determination device 212 and a third index determination device 213 . Their functions are identical to those which were described with reference to Fig. 5, Fig. 11, Fig. 12 and Fig. 13, and are realized by the processor 101 a, the humor in agreement with the in the program memory 101 b vomit programs. For this purpose, the first index determination device 211 is connected to receive the output signal (i) of the first envelope / signal amplitude detector 205 , as is the system control device 101 according to FIG. 4, which operates as shown in FIG. 5. The second index determination device 212 is connected to receive the output signal (c) of the second envelope / signal amplitude detector 207 , as is the system control device 101 of FIG. 9, which operates as shown in FIG. 11. The third Indexbestim mung device 213 is switched so that the output signal (b) receives the second sheath / signal amplitude detector 207, as it is the second system control device 101 of FIG. 9, which as shown in FIG. 12 or FIG. 13 is working.

A selector 215 selects one from the first to third indexes, which are output from the first to third index determination devices 211 to 214 . The selection is made in such a way that the reliability of the tilt compensation is improved ver.

That is, the selector 215 selects the index from the first to third index, which enables the most accurate slope compensation. To this end, before actually reproducing data from an optical disk, the system controller 101 determines the index through which a signal with the best reproduction quality can be obtained with respect to data jitter, the address detection error rate and the like in the sector identification. Information area, which are provided by the address reproduction unit 27 . In this case, the address reproducing unit 27 is required to have an error detection function.

The invention with the configuration described above has the following effects.

The disc drive according to the invention does not require additional system for tilt compensation, because the drive by using a signal that through  an output signal from the photodetector, which he will hold when the light spot hits the first sector identification information area tracked, and a Output signal, which is obtained when the Spot the second sector identification informa range is determined, as an index, the relative inclination between the disc and the head so controls that the index approaches an ex treme value is effected. Consequently, an increase the cost of the drive can be reduced.

According to the invention, the indices for the Nei hardly compensation by the track deviation com pensation influenced. Therefore, even if the Inclination compensation and the lane departure compensation tion are carried out together, only the inclination can be compensated in a simple manner without consideration tracking deviation compensation.

Claims (6)

1. disk drive for compensating for the inclination between a disk, comprising a first sector identification information area which is displaced radially outward from the center of a track by a predetermined distance and a second sector identification information area which is displaced radially inward by the same distance, and a head for forming a light spot on the disk, characterized by
a photodetector ( 15 ) for receiving light reflected at the light spot,
means (101, S25, S35, S47) for determining a sum signal from an output signal of the photodetector obtained when the light spot follows the first sector identification information area and an output signal obtained when the light spot reaches the second sector identification information area, and
a tilt controller (101, S11, 102) for using the sum signal as an index to control the relative tilt between the disc and the head so that the index approaches an extreme value. 2. Disc drive according to claim 1, characterized records that a sum signal from a sum signal amplitude of the photodetector obtained becomes when the point of light the first identifica tion information area followed, and one  Sum signal amplitude which is obtained when the light spot has the second identification Information area happens as the index is used. 3. Disc drive according to claim 1, characterized records that a sum signal from a Diff renzsignalamplitude from the photodetector, wel cher is obtained when the point of light he Verify most identification information area follows, and a difference signal amplitude, wel che is obtained when the light spot hits the two traced the identification information area, as the index is used. 4. Disc drive according to claim 1, characterized records that a sum signal from an Abso value of a difference between an envelope a difference signal from the photodetector, which is obtained when the point of light reaches the first identification information area ver follows, and a reference level, and an absolute worth a difference between an envelope a difference signal obtained when the light point the second identification information mation range tracked, and a reference level as the index is used. 5. disk drive for compensating for the inclination between a disk containing a first identification information area which is displaced radially outward by a predetermined distance from the center of a track, and a second identification information area which is displaced radially inward by the same distance, and a head for forming a light spot on the disk, characterized by
a photodetector ( 15 ) for receiving light reflected at the light spot,
means (101, S55) for determining a difference signal or an absolute value of the difference signal of an output signal from the photodetector obtained when the light spot traces the first identification information area and an output signal obtained when the light spot traces the second identification information area ver follows, and
a tilt controller (101, S11) for using the difference signal or an absolute value of the difference signal as an index to control the relative tilt between the disk and the head so that the index approaches an extreme value. 6. Disc drive according to claim 5, characterized records that a difference signal or an abso Luter value of the difference signal of an envelope the difference signal from the photodetector, wel ches is obtained when the point of light he Verify most identification information area follows, and an envelope of a differential si gnals, which is obtained when the light point the second identification information item richly followed when the index is used.