JPH05182223A - Optical recorder - Google Patents

Abstract

PURPOSE:To plot an ideal track locus in the case of recording even in an optical recording medium having no preformatted track. CONSTITUTION:An optical recording medium 12 is irradiated by a beam from a light source through a rotary light scanning system and information is recorded on the recording medium 12. Previous to recording the information on the optical recording medium, a reference recording medium 50 formed by the ideal track locus is reproduced while tracking-controlling. The information dealing with the tracking control obtained at this time is stored in a waveform memory 43. The displacement asynchronous with the rotation in direction intersecting the scanning direction of a light spot generating in the rotary light scanning system is detected by a detecting means 61. The target value of the scanning position of the light spot is formed based on the information stored in the waveform memory 43 and the displacement of a rotation asychronism detected by the detecting means 61, and the information is recorded while tracking-controlling so as to coincide with the target value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording method and apparatus for recording information on an optical recording medium such as an optical tape or an optical card.

[0002]

2. Description of the Related Art Conventionally, in a recordable optical disc, a preformatted track called a pregroove is generally recorded, and information is recorded while referring to the pregroove and performing tracking control. Therefore, in this case, if an ideal trajectory is formed as the track trajectory of this preformat, a recording track close to the ideal track can be formed.

By the way, there has been proposed an optical recording / reproducing apparatus which uses a flexible optical recording medium such as an optical tape as an optical recording medium (for example, Japanese Patent Laid-Open No. 62-11).
2234, JP-A-63-103440, etc.). In this optical recording / reproducing apparatus, for example, an optical tape is wound in a predetermined angle range on the peripheral surface of a rotating drum, and light from a laser light source provided outside the rotating drum is used in an image rotator (image rotating optical system) and a rotating drum. A mirror on the
An optical signal is recorded by irradiating the optical tape with a rotating optical scanning system including an objective lens, and obliquely scanning the optical tape.

In this case, a multi-beam is used as the light beam, and the light beam is rotated by a rotary scanning system so that the light beam scans the optical tape as the drum rotates. In this case, when the beam is separated from the rotation axis of the drum, the position of the light spot on the optical recording medium changes due to the rotation of the mirror in the drum. This problem can be solved by an image rotation optical system that causes rotation of the image about the optical axis when rotated.

The image rotator is for that purpose,
For example, it is composed of a rotating body using an image rotating prism such as a Dove prism or a Dach prism, and gives an image of a stationary object rotating at a rotation angle twice the rotation angle. Therefore, the image rotator is adapted to rotate in synchronization with the drum at a rotation speed which is half the rotation speed of the drum.

In this case, information is recorded on the optical tape by forming oblique linear tracks in the same manner as in magnetic recording.

[0007]

By the way, generally, in an optical tape as an optical recording medium of this kind, a pre-format reference track such as a pre-groove of an optical disc is not formed. For this reason, the linearity of the recording track on the optical tape is determined by the mechanical accuracy of the recording device, and the recording track locus causes track bending caused by the rotating optical scanning system such as an image rotator and a rotating drum.

In this case, when the error period that causes the track bending is equal to one rotation period of the drum, the recording track loci are formed every one rotation of the drum and thus become parallel to each other, and crosstalk between adjacent tracks occurs. Is less dangerous.

However, as described above, the rotation cycle of the image rotator is two rotation cycles of the drum. Therefore, the period of the track bending error ER, which is generally sinusoidal, is two rotation periods of the drum, and as shown in FIG. 13, one rotation period TA of the first half of the one rotation period of the image rotator and one rotation period of the second half of the drum. The error ER has the opposite polarity in the rotation period TB. Therefore, as shown in FIG. 14, a recording track 2A formed in the period TA and a recording track 2 formed in the period TB on the tape 100.
There is a risk that the direction of bending with respect to B is reversed and crosstalk occurs between these adjacent tracks.

The track bending caused by the image rotator is due to the accuracy of the image rotator prism, and cannot be removed even if the optical position adjustment is performed with high accuracy. Therefore, in order to escape this crosstalk, it is necessary to widen the track pitch,
There was a drawback that the recording density was lowered.

Further, when there is a different track bend in each recording device as described above, when a tape recorded by a certain recording / reproducing device is reproduced by another recording / reproducing device, due to the difference in the track bending amount of these devices, The load on the servo system will increase. This also occurs when the error period is equal to one drum revolution period.

Even when a polygon mirror or other polygonal mirror is used without using an image rotating optical system such as an image rotation prism (for example, Japanese Patent Laid-Open Nos. 61-34740 and 62-162261). Etc.), the track locus drawn by each mirror surface differs due to the arrangement error of each mirror surface, the aberration, etc., and the same problem as described above occurs.

Therefore, the applicant previously filed Japanese Patent Application No. 3-22.
No. 4569 (filed on July 26, 1991), an optical recording method was proposed in which an ideal track locus without track bending can be formed as a recording track during recording.

The previously proposed optical recording method reproduces information while recording information on an optical recording medium such as an optical tape while tracking control of a reference recording medium having an ideal track locus, for example, a linear track. Then, the light spot is accurately scanned along the ideal track. Then, the information related to the tracking control obtained at this time is stored in synchronization with the rotation of the drum motor and the rotator motor. Then, in actual recording, the stored information related to the tracking control is read in synchronization with the rotation of the drum motor and the rotator motor, and this is used as a target value to draw an ideal track locus on the optical recording medium. The information is recorded while controlling the scanning of the recording light spot.

In the previously proposed optical recording method, the target value for correcting the track bend and forming the straight track is stored in synchronization with the rotation of the drum motor and the rotator motor. The track bending can be corrected only for the component synchronized with the rotation of the rotator motor.

However, the displacement that causes the track bending includes a component that is generated in synchronization with the rotation of the rotary light scanning system and a component that is not synchronized with the rotation. For example, during displacement of the optical scanning spot in the thrust direction (axial direction) of the drum rotation shaft due to shaft shake or mechanical disturbance of the drum motor, there is a component that is asynchronous with the rotation of the drum motor.

The shaft runout occurs between the rotary shaft of the drum motor and its bearing. For example, in a rolling bearing, shaft runout occurs due to the revolution cycle of the rolling element (not necessarily synchronized with the rotation of the motor shaft). The shaft runout due to the revolution cycle of such rolling elements is generally “N
This is called RRO (non-repeatable run-out), and the component of this shaft runout is usually asynchronous with the rotation of the drum motor.

Therefore, when an ideal track, for example, a linear track is formed by using only the storage target value synchronized with the rotation as described above, the linearity of the track is maintained due to the shaft runout of the drum motor. Will disappear.

The shaft runout is 1/2 of the track pitch.
In the above case, the scanning position of the light spot deviates from the center of the straight track as an example of the ideal track, and approaches the tracking pull-in range of the adjacent track, which causes mistracking. For this purpose, for example, 1μ
The track pitch cannot be reduced to 2 μm or less if there is mp-p axial runout. That is, in the past, the increase in recording density was limited by the shaft runout accuracy of the rotary drum.

In order to increase the accuracy of shaft runout of the rotary drum, it is possible to improve the bearing so that it has higher accuracy.
However, in that case, the bearing becomes large, and
It becomes expensive and unsuitable for an optical recording / reproducing apparatus.

In view of the above points, the present invention is an optical recording apparatus capable of forming an accurate ideal track locus for recording even if there is a track bending component that is asynchronous with the rotation of the rotary optical scanning system. The purpose is to provide.

[0022]

In order to solve the above-mentioned problems, the optical recording apparatus according to the present invention makes the light source 1 and the light from this light source 1 on the optical recording medium 12 correspond to the reference numerals described later. A rotating optical scanning system for converging to form an optical spot and scanning the optical spot on the optical recording medium 12, and a tracking control for controlling the optical spot scanning position on the optical recording medium. Means 7, 33,
35, 36, and a correction signal generation means 43 for generating a scanning error correction signal for correcting a scanning error corresponding to the tracking deviation of the light spot with respect to the ideal track locus in synchronization with the rotation of the rotating optical scanning system. And a displacement detection means 61 for detecting a displacement in the rotating light scanning system in a direction intersecting the optical scanning direction, and a correction signal obtained from the correction signal generating means 61 and a detection means 61.
A target value of the scanning position of the light spot is formed on the basis of the displacement detection output from, and the information is recorded while the scanning control of the light spot is performed by the tracking control unit so as to match the target value. It is characterized by

Further, there is provided an extracting means 65 for removing a component synchronized with the rotation of the rotating light scanning system from the displacement detection output of the detecting means 61 and extracting a component asynchronous with the rotation, and from the correction signal generating means 43. A target value of the scanning position of the light spot is formed from the obtained correction signal and the component asynchronous with the rotation obtained from the extracting means 65, and the tracking control means adjusts the light spot of the light spot so as to match the target value. It is more preferable to record the information while controlling the scanning.

[0024]

According to the above-described structure of the present invention, the displacement detecting means 61 detects the light spot shake in the direction intersecting the optical scanning direction, for example, the thrust direction of the rotary drum. This spot shake includes a component asynchronous with the rotation, and the target tracking position is formed from this and the correction signal from the correction signal generating means 43. Then, the light spot is subjected to tracking control so as to scan the target tracking position and recording is performed.

When the extraction means 65 is present, the component synchronized with the rotation is removed from the output of the displacement detection means 61,
Only components asynchronous to rotation are extracted.

Then, tracking control is performed so that the optical scanning spot scans the target tracking position formed by the extracted component asynchronous with the rotation and the scanning error correction signal synchronized with the rotation of the rotating optical scanning system. , Recording is done. Therefore, a recording track closer to the ideal track locus is formed on the optical recording medium to record information.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings, taking the case of application to an optical tape recording / reproducing apparatus as an example. FIG. 1 shows the optical system of the optical tape recording / reproducing apparatus of this example, and FIG. 2 shows the optical tape running system.

A light beam emitted from a semiconductor laser 1 as a light source is converted into parallel light by a collimator lens 2, and is incident on a galvanometer mirror 7 via a polarization beam splitter 3 and a quarter wavelength plate 4 and reflected. After that, the light enters the image rotator 9. In the image rotator 9, for example, the Dach prism 9V is held within the axis of the rotator motor 8 to form an image rotation optical system.

The light beam emitted from the image rotator 9 is reflected by the mirror 10 provided in the rotary drum 13, and the objective lens 11 forms a scanning spot on the optical tape 12. The optical tape 12 is a drum 1 including a rotating upper drum 13 and a fixed lower drum 14.
5 is obliquely wound around the peripheral surface of No. 5 over an angular range of 180 degrees.

The light beam reflected from the optical tape 12 returns to the opposite path, and by the ¼ wavelength plate 4 and the polarization beam splitter 3, it enters a signal detection system composed of a detection converging lens 5 and a multi-division detector 6. Be guided.

The rotating upper drum 13 is rotationally driven by a drum motor 16. The Dach prism 9V of the image rotator 9 is fixed to the shaft of the rotator motor 8 as described above, and is rotated by the rotator motor 8 in synchronization with the rotation of the rotary drum 13. However, in this case, the image rotator 9 is designed to rotate synchronously at a half rotation speed of the rotary drum 13 as described above.

Further, by rotating the galvanometer mirror 7 in the direction indicated by the arc-shaped arrow in the figure, the angle of the optical axis is adjusted so that the optical scanning spot obliquely tracks on the optical tape as described above. At the same time, the scanning position in the width direction of the recording track (tracking control direction orthogonal to the track scanning direction) is controlled. That is,
The position of the light spot is controlled by the galvanometer mirror 7 and the image rotator 9, and the light spot moves in the track scanning direction.

In this case, the rotation angle position of the galvanometer mirror 7 is detected as follows. That is, the LED 17
The emitted light of is collimated by the collimator lens 18,
It is incident on the back side of the galvanometer mirror 7. Then, the reflected light is incident on the position detection element 20 including a one-dimensional CCD line sensor through the converging lens 19. The spot position of the light incident on the position detection element 20 corresponds to the rotation angle position of the galvano mirror 7, and serves as a position detection signal indicating the light spot position on the tape 12. The rotation angle position of the galvanometer mirror 7 can be detected from the position detection signal from the position detection element 20.

In this example, on the surface side of the rotating upper drum 13 facing the fixed lower drum 14, the thrust direction of the light spot (the drum motor 16 of the drum motor 16) is located immediately below the position where the light spot is formed. A displacement detector 61 for detecting a shake in the rotation axis direction = the direction orthogonal to the optical scanning direction = the tracking control direction) is attached. The shake of the light spot in the thrust direction also includes the axial shake displacement of the drum motor 16. Displacement detector 6
1 is a rotary upper drum 13 and a fixed lower drum 14
It is detected as the displacement of the gap Δe between and. Displacement detector 6
The mounting position of 1 may be another position on the surface of the rotating upper drum 13 facing the fixed lower drum 14.

As the displacement detector 61, for example, AD
A capacitance type displacement gauge such as Microsense manufactured by E can be used. In this example, the displacement detector 61 detects the displacement of the rotating upper drum 13 with respect to the fixed lower drum 14 in the thrust direction as a capacitance change.

Next, the tape running system will be described with reference to FIG. The optical tape 12 is pulled out from the supply reel 21 and guided by the guide 22 to the entrance guide 23. By the entrance guide 23 and the exit guide 24, the tape 12
Is obliquely wound around a 180-degree angular range section around a drum 15 including an upper drum 13 and a lower drum 14.
In this 180-degree tape winding section, the rotating upper drum 1
Recording / reproduction is performed on the tape 12 by the laser spot formed by the objective lens 11 on 3.

The tape 12 is pressed against a capstan shaft 25 of a capstan motor 26 by a pinch roller 27 and sent, and wound on a take-up reel 28.

Information signal recording tracks TR as shown in FIG. 3 are formed on the optical tape 12 by the optical recording / reproducing apparatus having the structure shown in FIGS.

When there is a pre-formatted track (pre-groove) such as an optical disc, the multi-divided detector 6 of the signal detection system receives the reflected light from the pre-formatted track, and the multi-divided detector 6
By obtaining a tracking error signal from the output signal of the control signal and controlling the rotation angle of the galvano mirror 7 to perform tracking control to follow the preformatted track, recording is performed to make the recording track locus almost ideal. can do.

However, in the case of the above-mentioned optical tape, since there is no pre-formatted track, the tracking control is not performed as it is, and a recording error occurs in the recording track locus which causes the above-described mechanically accurate track bending.

In order to avoid this, according to the present invention, a scanning error correction signal for drawing an ideal track locus is stored in advance prior to recording, and the like, so that tracking control can be performed during recording. Try to record while calling. The scanning error correction signal is obtained as follows.

That is, in this example, a reference piece 50 having an ideal track locus (groove) 50TR as shown in FIG. 4 is prepared. In the case of the optical tape of this example, the grooves 50TR of the ideal track locus are straight and a plurality of grooves 50TR are formed at equal intervals. The size of the reference piece 50 may be any small piece capable of receiving a light spot. Of course, the size of the reference piece 50 may be the entire circumference of the rotary drum 13.

In this example, the reference piece 50 is attached to the rotating upper drum 13 and is rotated together with the rotating upper drum 13 with the longitudinal direction of the groove 50TR aligned with the ideal track scanning direction of the light spot.

Then, the apparatus is set to the reproduction mode, and the tracking control is applied so that the light spot is always positioned so as to correctly follow the groove 50TR as an ideal track. That is, from the multi-division detector 6 of the signal detection system,
Although a tracking error is obtained for the groove 50TR as the ideal track, the galvano mirror 7 is swung so that the tracking error becomes zero. At this time, the galvanometer mirror 7 obtained by the position detection element 20
The rotation angle position information of is stored in the memory in correspondence with the rotation phase information of the rotator 9.

At the time of actual recording of information on the tape, the reference piece 50 is removed and the optical tape 12 is wound over the 180-degree angle range of the drum 15 as shown in FIG. In addition,
This winding angle is arbitrary and may be 360 degrees. Then, the position information stored in the memory is used as the image rotator 9
The data is read in synchronization with the rotation phase of, and the galvanometer mirror 7 is driven based on this reading.

Then, the light spot scans on the optical tape so as to be positioned on the groove 50TR as the ideal track locus of the reference piece 50. As a result, a straight recording track is formed on the optical tape if there is no displacement in the rotation axis direction (thrust direction) that is asynchronous with the rotation of the drum.

FIG. 5 is a block diagram of an example of the optical recording apparatus according to the present invention. In this example, the displacement of the rotation of the upper drum 13 in the thrust direction, that is, the influence of the displacement asynchronous with the rotation of the upper drum 13 can be eliminated.

To facilitate understanding of the present invention, first,
A portion for performing recording tracking control using the scanning error correction signal synchronized with the rotation of the drum 13 and the image rotator 9 will be described.

In FIG. 5, S1, S2, S3, and S4 are mode changeover switches, which are switched to the contact A side in the track bending detection mode for obtaining the scanning error correction signal, and in the actual recording mode on the optical tape. , And to the contact B side.

In the track bend detection mode, the reference piece 50 is attached to the rotary drum 13, and in the optical tape recording mode, the optical tape 12 is wound on the rotary drum 13.

In the track bend detection mode,
The light flux from the light source (semiconductor laser 1) enters the reference piece 50 via the galvanometer mirror 7 and the optical system 31 including the image rotator 9, the mirror 10, the objective lens 11 and the like. Then, the reflected light from the reference piece 50 enters the multi-divided detector 6 via the returning optical system 32 (including the galvano mirror 7).

The output of the multi-divided detector 6 is supplied to the matrix circuit 33, from which the reproduced signal SF of the information signal and the tracking error TE are obtained. This tracking error TE is a signal corresponding to a case where the track pitch detected by the push-pull method is one cycle and the zero cross point is at the center of the track, and indicates the relative position between the track and the light spot. is there.

This tracking error TE is supplied to the galvanometer mirror drive circuit 36 via the switch S4 and the phase compensation circuit 35. Then, the galvano mirror driving circuit 36 rotationally drives the galvano mirror 7,
The tracking control is performed so that the light spot on the reference piece 50 is always correctly positioned on the groove 50TR as an ideal track formed on the reference piece 50.

The rotational angle position information of the galvanometer mirror 7 at this time is detected by the position detection element 20 and the position calculation circuit 41, and the position detection output SD is supplied to the A / D converter 42 and converted into digital data. And switch S1
Is input to the waveform memory 43 via. Waveform memory 43
In the track bend detection mode, the writing mode is set, and in the recording mode, the reading mode is set.

The address generator 47 uses the waveform memory 4
3 address signals are generated. This address generator 47
Is supplied with a pulse PG1 indicating the rotation phase of the drum from the drum motor 16 and a frequency signal FG1 indicating the rotation speed, and the rotation phase of the image rotator 9 from the rotator motor 8 synchronized with the drum motor 16. PG2 indicating the rotation speed and the frequency signal FG indicating the rotation speed
2 is supplied.

From the address generator 47,
An address signal synchronized with the rotation phases of the drum motor 16 and the image rotator 9 is obtained. This address signal corresponds to each position in the rotation direction obtained by dividing one rotation of the rotator motor 8 into 2N equal parts.

Therefore, in the track bending detection mode, the rotation of the galvanometer mirror 7 at each rotation angle position obtained by dividing one rotation of the rotator motor 8 into 2N equal parts (one rotation of the drum motor 16 into N equal parts). The angular position information is written in the waveform memory 43 according to the address signal from the address generator 47. Therefore,
The waveform memory 43 stores a rotation angle position waveform of the galvanometer mirror 7 such that a light spot scans a linear track as an ideal track for one rotation of the rotator motor 8 (two rotations of the drum motor 16). It is a thing.

Next, in the actual recording mode on the optical tape, the optical tape 12 is wound around the drum 13 as described above. At this time, the rotation angle position waveform of the galvanometer mirror 7 is read according to the address signal from the address generator 47. Since the switches S1 to S4 are switched to the contact B side,
The read position waveform data is supplied to the D / A converter 45 via the switch S2 and returned to the analog position signal, and this analog position signal is supplied to the subtractor 46 as a position reference signal via the switch S3. Supplied.

Then, the rotation angle position signal of the galvanometer mirror 7 from the position calculation circuit 41 at the time of the current recording is the subtractor 46.
Is supplied to. An error between the rotational angle position of the galvanometer mirror 7 and the reference rotational angle position signal at the time of recording is obtained from the subtractor 46, and the error from the subtractor 46 is the switch S.
4 and the phase compensating circuit 35 to the galvano-mirror driving circuit 36, which controls the turning angle of the galvano-mirror 7 to the reference turning angle position. Therefore, in this recording mode, the light spot is scan-controlled so as to form an ideal track locus, in this case, a straight track on the optical tape.

In the above scanning control, 1 of the drum 13
The detection waveform and the correction waveform generated for the rotation will be described with reference to FIG. In the figure, the pulse PG1 (FIG. 6A) is obtained every rotation period T (sec) of the drum motor 16, and the frequency signal FG1 (FIG. 6B) is obtained at the rate of N pulses within this one rotation period T.

When the component asynchronous with the rotation of the drum motor 16 or the external vibration (FIG. 6E) is so small as to be negligible, the deflection of the light spot in the thrust direction with respect to the rotating drum 13 is as shown in FIG. 6C. , Is a rotation synchronization component and has reproducibility at each rotation. However, when the component Ve that is asynchronous with respect to the rotation of the drum motor 16 such as the shaft runout or the external vibration is large, the movement of the light spot on the tape 12 is, as shown in FIG. 6D, the rotation synchronization component of FIG. The rotation non-synchronous component Ve is added.

In the method of forming a linear track as an example of an ideal track locus for recording by using the above-mentioned scanning error correction signal, the rotation synchronization component of FIG. 6C is removed, but the rotation asynchronous component Ve. Remains without being removed,
The accuracy of the linearity of the track drops.

This rotational non-synchronous component Ve is displaced by the displacement detector 61 shown in FIG. 1 relative to the upper surface of the fixed lower drum 14 of the rotary upper drum 13, that is, the gap between the rotary upper drum 13 and the fixed lower drum 14. It can be detected by detecting the displacement of Δe.
Then, by adding this to the scanning error correction signal,
It is possible to correct the track bend due to the non-rotational component.

By the way, in this case, the displacement detector 61 detects the displacement of the light spot in the thrust direction.
Gap Δe between the rotating upper drum 13 and the fixed lower drum 14
Is the displacement of. There is no problem if the upper surface of the lower drum 14 is uniformly flat, but it is difficult to maintain the flatness in the order of μm. Therefore, the displacement detected by the displacement detector 61 includes a rotation synchronization component (see FIG. 6F) due to the non-flatness of the upper surface of the lower drum 14, and the detected displacement is
The displacement Vd is as shown in FIG. 6G.

Therefore, in this example, from the detection output Vd (FIG. 6G) of the displacement detector 61, the lower drum 1 shown in FIG. 6F is obtained.
4 eliminates the rotation synchronization component due to the non-flatness of the upper surface,
Non-rotational component V of the light spot shake in the true thrust direction
e, and only the rotation asynchronous component Ve is acquired by the waveform memory 43.
Is added to the scanning error correction signal from (1) to form a linear track during recording.

That is, in FIG. 5, the displacement detector 61
As a result, the light spot deflection displacement is detected as the displacement of the rotating upper drum 13 in the thrust direction. Here, the displacement detector 6
What is detected by 1 is the displacement Vd including the rotation synchronization component due to the non-flatness of the upper surface of the lower drum 14. The detected displacement Vd is adjusted in gain by the detection amplifier 62 and then supplied to the low-pass filter 63 to suppress high-frequency noise components and supplied to the A / D converter 64.

In this A / D converter 64, the displacement V
d is sampled by the frequency signal FG1 and the sampled value is converted into digital data. Each pulse position of the frequency signal FG1 corresponds to the rotation angle position on the rotating drum 13, and is the first position for one rotation section of the drum 13 indicated by the address signal from the address generator 47.
The data corresponding to the address to the Nth address, and the kth rotation data is xi [kT] (where i = 1, 2, ... N).
And T is the rotation period of the drum motor).

This digital data is supplied to the digital comb filter 65. The digital comb filter 65 is for removing the drum rotation synchronizing component from the displacement Vd and extracting only the asynchronous component Ve.

FIG. 7 shows this digital comb filter 6
5 shows an example of the configuration of No. 5, and input data from the input terminal 71 is supplied to the subtractor 72. The output of the subtractor 71 is supplied to the memory 74 via the adder 73, and according to the address signal from the address generator 47 (however, the address signal is one rotation cycle of the upper drum 13 excluding the most significant bit). Written. The data read from the memory 47 is supplied to the adder 73 and the subtractor 7
In addition to being added to the output of 2, the gain is multiplied by K in the amplifier 75, supplied to the subtractor 72, and subtracted from the input data. Then, the output of the subtractor 72 is taken out from the output terminal 76 as the output data yi [kT].

The operation of the digital comb filter 65 will be described with reference to FIGS. When the scanning position of the light spot reaches the first pulse position of the frequency signal FG1 counted from the pulse PG1 at the k-th rotation, the digital data x1 [] of the displacement Vd from the A / D converter 64 at that rotation angle position is obtained. kT] is input to the digital comb filter 65 through the input terminal 71.

The input data x1 [kT] is used as the subtractor 7
2, the output y1 up to one rotation before at the same rotation angle position
The difference from [(k-1) T] multiplied by the gain K is calculated, and the output value y1 [kT] at the kth rotation is obtained. This output y1 [kT] is led to the output terminal 76, and at the adder 73, the cumulative value y of the output y1 up to one rotation before is obtained.
1 [(k-1)] and is stored in the memory 74 as a cumulative value up to k rotations. The upper drum 13 rotates, 2
At the pulse position of the th frequency signal FG1, the data x2 [kT] is input from the input terminal 71. At the same time, the address of the memory 74 is updated and the same calculation as described above is performed. This is sequentially repeated in each one rotation section of the upper drum 13.

FIG. 8 shows a calculation example of the frequency response at this time. In the example of FIG. 8, the rotation frequency is 10 Hz (T = 1/10
sec), the gain K = 1/8, and the sample value of the output obtained by removing the component of an integral multiple of the rotation cycle of the drum 13,
That is, it can be seen that the rotation synchronization component is removed and only the asynchronous component Ve is obtained from the digital comb filter 65.

In the above embodiment, as the correction signal generating means for correcting the scanning error of the light spot at the time of recording,
The waveform memory 43 is used to store the rotation angle position of the galvanometer mirror 7 when scanning the ideal track formed on the reference piece 50 based on the rotation phase information for one rotation of the image rotator 9. The present invention is not limited to this. For example, a tracking error when scanning an ideal track formed on the reference piece 50 from the matrix circuit 33 may be stored based on the rotation phase information of the image rotator 9.

In the above example, the rotation angle of the galvanometer mirror 7 is controlled to perform tracking control.
The tracking control method is not limited to this. For example, a tracking control method in which the objective lens 11 is driven in the tracking control direction by a piezoelectric element or the like may be used. In this case, the position of the objective lens 11 in the tracking control direction is detected by the position detector. As the correction signal generating means, the reference piece 50 is reproduced and the groove 5
The position of the objective lens 11 in the tracking control direction when the tracking control is performed with respect to 0TR may be detected by this position detector and stored in the waveform memory based on the rotation phase information of the image rotator 9.

Further, in the above example, the sampling of the data at each rotation angle position of the deflection displacement in the thrust direction of the rotary drum 13 is performed by the frequency signal FG1, but the frequency signal FG1 is used to remove higher frequency components. A synchronized sampling clock may be created by using a PLL or the like and used.

In the above example, the correction waveform stored using the reference piece 50 and the displacement detection signal Ve are added as digital data, but they may be added after being converted into analog signals. .. Also, the waveform memory 4
The correction waveform stored in 3 and the displacement detection signal Ve are synchronized with the frequency signal FG1, and may be sampled by sampling clocks having different periods.

Further, although the correction by the displacement detection signal Ve is performed in the drum rotation cycle, it may of course be performed in the rotation cycle of the image rotator 9. In this case, in FIGS. 6 and 7, the address for two rotations of the drum 13 is i =
The address for the memory 74 may be set to 1 to 2N.

Further, in the above-mentioned example, although the rotation synchronizing component is removed from the drum shake detection signal in the thrust direction by the digital comb filter, the rotation synchronizing component and the rotation asynchronous component are largely different in frequency. Sometimes
A digital or analog low-pass filter, band-pass filter, or high-pass filter can be used.

The position of the displacement detector 61 is shown in FIG.
For example, as shown in FIG. 9, the mounting arm 82 is fixed to the lower drum 14, the displacement detector 61 is mounted at the tip of the arm 82, and the rotating upper drum 13 is not limited to the position shown in FIG. The axial runout displacement of the drum motor may be detected by detecting the displacement of the upper surface in the thrust direction. Further, as shown in FIG. 10, the mounting arm 8 to which the displacement detector 61 is mounted is attached.
1 may be attached to the base 82 to which the lower drum 14 is fixed.

In the above example, the displacement detector 61
Uses a capacitance detection type, but other detectors can also be used. For example, Multi-Vit manufactured by KAMAN Co. for detecting eddy current change with the opposing conductive surface, or an optical lever type for detecting positional deviation of return light by obliquely injecting laser light to the opposing surface (for example, Anritsu optical micro, Many such as those manufactured by Keyence Co., Ltd.), or a photonics sensor that emits halogen light through an optical fiber and detects the amount of returned light can be used as long as it can measure displacement in a non-contact manner.

Further, in the above example, the case of the upper drum rotation type has been described, but the middle drum rotation type as shown in FIG. 11 and the fixed drum rotation part retracted type as shown in FIG. It is possible to obtain the same effect as described above by detecting the displacement of the part that is coincident and is connected to the rotary shaft of the drum by the detector 61.

The optical recording medium can be applied not only to an optical tape but also to a system for recording and reproducing on a recording medium such as a flat sheet medium or a card medium (for example, refer to Japanese Patent Laid-Open No. 59-223949). is there.

Further, in the above example, the image rotator using the Dach prism is explained, but the present invention is not limited to this, and for example, dove, dove, schmidt, ave, bee block, petchan, and other image rotation. A system may be used.

Further, the present invention is not limited to the one using the image rotating optical system, but can be applied to any one which produces reproducible track bending depending on the rotation angle of the rotating light scanning system. For example, in the case of a rotating optical scanning system using a polygon mirror, when each surface of the polygon mirror has an angular error, the track loci scanned by each surface are different, but even in this case, by using the present invention, It is possible to remove the bending of the scanning trace of the surface and form a recording track with good linearity. Further, the present invention can be similarly applied to a rotary light scanning system using a polygon mirror.

Further, according to the present invention, a correction signal generating means for drawing an ideal track locus can be constructed by using a fixed wave generator whose amplitude, waveform and phase can be adjusted instead of the waveform memory.

The present invention can also be applied to an apparatus that does not use a rotary drum. Further, the ideal track locus is not limited to the straight case, but becomes the arcuate track locus when the light spot is scanned in the arcuate shape to draw the arcuate track locus.

[0087]

As described above, according to the present invention, even when recording is performed on an optical recording medium having no preformatted track, a recording track is always formed by forming an almost ideal track locus at the time of recording. It is possible to record the information signal. In addition, since the ideal track locus can be formed by removing the influence of the component asynchronous with the rotation of the rotary light scanning system, the track pitch can be further narrowed and higher recording density can be achieved. In addition, compatibility between different recording / reproducing devices is improved.

Furthermore, according to the present invention, since it is not necessary to use a highly accurate bearing for preventing shaft runout of the drum motor, it is advantageous in terms of downsizing and cost of the apparatus. Also,
Further, it is not necessary to perform highly accurate adjustment as in the past to draw an ideal track locus, and the adjustment becomes easy.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an optical system when the present invention is applied to an optical tape recording / reproducing apparatus.

FIG. 2 is a diagram showing an example of an optical tape running system when the present invention is applied to an optical tape recording / reproducing apparatus.

FIG. 3 is a diagram showing a recording track pattern on an optical tape.

FIG. 4 is a diagram showing a main part of another example of the optical system of the recording apparatus of the present invention.

FIG. 5 is a block diagram of an embodiment of a tracking servo circuit when the present invention is applied to an optical tape recording / reproducing apparatus.

6 is a diagram for explaining a signal waveform of each part of FIG.

FIG. 7 is a diagram showing a configuration of an example of a digital comb filter as an example of an asynchronous component extraction circuit.

FIG. 8 is a diagram for explaining the operation of the digital comb filter of the example of FIG.

FIG. 9 is a diagram showing another example of the mounting position of the displacement detector.

FIG. 10 is a diagram showing another example of the mounting position of the displacement detector.

FIG. 11 is a diagram showing another example of a rotary drum device.

FIG. 12 is a diagram showing another example of a rotary drum device.

FIG. 13 is a diagram for explaining occurrence of a track bending error due to rotation of a rotator.

FIG. 14 is a diagram showing an example of track bending on a tape.

[Explanation of symbols]

 1 Semiconductor Laser 3 Polarizing Beam Splitter 4 1/4 Wave Plate 6 Multi-Division Detector 7 Galvano Mirror 8 Rotator Motor 9 Image Rotator 10 Mirror 11 Objective Lens 12 Optical Tape 13 Rotating Upper Drum 14 Fixed Lower Drum 16 Drum Motor 20 Position Detection Element 33 Matrix circuit 43 Waveform memory 47 Address generator 61 Displacement detector 65 Digital comb filter

Claims (2)

[Claims] 1. A light source, and a rotating light scanning system for converging light from the light source on an optical recording medium to form a light spot and scanning the light spot on the optical recording medium. Tracking control means for controlling a light spot scanning position on the optical recording medium, and a scanning error correction signal for correcting a scanning error corresponding to a tracking deviation of the light spot with respect to an ideal track locus, A correction signal generating unit that is generated in synchronization with the rotation of the scanning system, and a detection unit that detects a displacement in a direction intersecting the optical scanning direction that occurs in the rotating optical scanning system, are obtained from the correction signal generating unit. A target value of the scanning position of the light spot is formed on the basis of the correction signal and the displacement detection output from the detection means, and the track is made to match the target value. Optical recording apparatus that records information while performing scanning control of the beam spot by grayed control means. 2. A correction obtained from the correction signal generating means by providing extraction means for removing a component synchronized with the rotation of the rotary light scanning system from a displacement detection output of the detection means and extracting a component asynchronous with the rotation. The optical recording apparatus according to claim 1, wherein a target value of a scanning position of the light spot is formed from a signal and the extracted rotation non-synchronous component.