JPH07296396A - Optical recording/reproducing method and optical disc - Google Patents

Abstract

PURPOSE:To realize a high density recording/reproducing without requiring a high degree micromachining by performing non-tracking recording/reproduction while shifting the focus stepwise in the radial direction for every predetermined feeding amount or revolution. CONSTITUTION:When non-tracking projection of reproducing light is effected, the center of tracking matches the center of rotary axis, and since the recording track matches the center of emboss pit or guide groove, the track of reproducing light intersects the recording track. When the focus 302 of reproducing light is located in the center of a track 301, only such an error as caused substantially by a defect is present but an error caused by cross-talk increases as the focus 302 more departs from the center of track. When the feeding amount per a revolution of reproducing light is set lower than the recording track pitch, reproduction can be effected again at a position separated by a distance shorter than the recording track pitch from the position irradiated previously upon occurrence of cross-talk.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording / reproducing method for non-tracking an optical disc.

[0002]

2. Description of the Related Art At present, a disc which is irradiated with light for recording and reproducing has already been put into practical use. A typical playback-only disc is widely used as a playback-only memory for music and computer external storage. Moreover, what can be recorded and reproduced has been put to practical use for music in addition to computer external storage. When recording or reproducing these disks, in order to form or reproduce pits of a very small submicron order, a laser beam having good coherence is used for focusing with a lens. In addition, tracking is performed to increase the recording density in the radial direction of the disc. Tracking is performed by moving the optical head roughly as the recording track is read or by moving the write position, and by driving the coarse motor to follow the low-frequency component of track shake and the high-frequency component of track shake. The objective lens is supported by a leaf spring or the like, and a two-stage servo for driving such as a voice coil motor for finely moving the objective lens is used.

Here, the tracking particularly refers to the latter.
There are three beam methods, push-pull methods, track wobbling methods, etc. as methods for detecting the tracking error signal. In any case, guide grooves, embossed pits, etc. are formed along the recording track on the disk surface. Then, the tracking error signal is detected by irradiating light and using the diffraction effect. The tracking error signal contains system noise including the optical head and the tracking servo circuit. Furthermore, noise due to improper shape of the guide groove, embossed pit, etc. of the disc is mixed. Therefore, as the eccentricity of the disk and the disturbance to the drive portion increase, a tracking error signal of higher intensity is required. However, when the track pitch becomes smaller as the density of the disc becomes higher, the guide groove becomes thinner and the wobble pit becomes smaller, and it becomes difficult to obtain a sufficient tracking error signal. On the contrary, forming a fine line guide groove or a small wobble pit on the disk surface requires a high level of fine processing technology, which is a major obstacle to high density.

In the optical recording medium shown in FIG. 1 of Japanese Patent Application No. 4-156471, information is formed as a heat shield layer on the side opposite to the reading surface. Since the first dielectric layer, the magneto-optical recording layer, the second dielectric layer, and the reflective layer are formed between the reading surface and the heat shield layer, the light is attenuated by these layers and the intensity of the light is reduced. It is not possible to read out the thermal barrier layer pattern as a modulation. Therefore, the guide groove or the wobbling pit must be formed on the read surface separately from the heat blocking layer pattern. However, the guide groove or the wobbling pit row must be aligned with the heat blocking layer pattern row, and both-side alignment is required. However, the pitch of these rows is about 1.5μ even with the current technology.
m, and may be 1 μm or less depending on future technological trends. It is very difficult to align both sides of this fine pattern.

On the other hand, a magnetic tape storage medium that has been used for helical scan azimuth recording and that has non-tracking reproduction has been put into practical use. By performing reproduction at a pitch smaller than the pitch of the recording track. Japanese Patent Laid-Open No. 58-77 discloses non-tracking.
No. 009 publication. Similarly, in performing non-tracking reproduction, Japanese Patent Laid-Open No. 3-116403 discloses that a memory to be written is provided according to a block address signal, and the digital information signals written in the memory are read out in a predetermined order to make them continuous. Has been done. In addition, when performing non-tracking reproduction as well, the recording track is divided into a plurality of blocks, the block address signal is reproduced and input to the address map storage device as information, and detection information indicating whether or not the block address was reproduced correctly can be obtained. Japanese Patent Laid-Open No. 3-178094 discloses that map information representing a scanning situation is formed by writing and the quality of the scanning locus is evaluated by the map information.
It is described in Japanese Patent Publication No. In the optical card, a method of reconstructing the reproduced waveform without azimuth shift by making a pit map digitized on the RAM from the reproduced waveform without using the tracking servo and applying the recognition technology,
Optical Memory Symposium '88 Proceedings, P61.

[0006]

However, as compared with a magnetic tape or an optical card for performing helical scan azimuth recording, an optical disc has a long track length and a low linear density, and therefore has a large amount of information per track. When outputting continuous data in non-tracking playback, the information for all tracks traversing one revolution must be temporarily stored, and the amount of information becomes very large. The capacity of the storage device becomes large. Also, the processing of that information is burdensome. Although it is considered that non-tracking reproduction is possible, the track pitch cannot be narrowed and it is considered unrealistic for a large-capacity optical disk.

Further, in the optical recording medium in Japanese Patent Application No. 4-156471, it is indispensable for the case where it is difficult to form the tracking guide groove and the wobble pit.

An object of the present invention is to provide an optical recording / reproducing system which enables the above problems.

[0009]

SUMMARY OF THE INVENTION The above-mentioned problem is to perform optical recording / reproducing using an optical recording / reproducing apparatus having a driving means for coarsely moving an optical head in the radial direction for recording or reproducing information on an optical disc and a tracking error detecting means. In the method, an optical recording / reproducing method in which scanning of an optical focus is performed by non-tracking, and the non-tracking is recording / reproducing for an optical disc capable of recording / reproducing, and reproducing for an optical disc capable of only reproducing, An optical recording / reproducing method comprising forming or reproducing a spiral recording track by moving the optical focal point scanning in the radial direction at a constant speed, and irradiating an eccentricity detecting portion on the optical disk with light. The track deviation is detected, the amplitude and phase of the fundamental frequency component of the track deviation is detected by an eccentricity detector, and An optical recording / reproducing method in which the rack shake and the fundamental frequency are the same, and a sine wave having a constant phase difference with the track shake is output by a sine wave output circuit, and a deviation of an optical focus position with respect to a recording track is reduced. An optical recording / reproducing apparatus having a driving means for roughly moving the optical head in the radial direction, a driving means for finely moving the objective lens in the radial direction, and a tracking error detecting means is used, and light for driving the objective lens by the radial actuator with the sine wave. A recording / reproducing method, an optical recording / reproducing apparatus having a driving unit for roughly moving the optical head in the radial direction and a tracking error detecting unit, and a light for driving the optical head by superimposing the sine wave on the drive signal of the driving unit. The recording / reproducing method and the recording track are divided into a plurality of blocks. When the block address signal and the data in the block are reproduced at the time of reproduction, including the detection code and data, the error detection code is used for error detection, and if the error detection is good or bad, it corresponds to the block address. An optical recording / reproducing method for transferring data of the block to a predetermined address of a buffer memory,
An optical disc having guide grooves or wobbling pits provided at a plurality of locations in the optical disc, the first eccentricity detecting portion width being larger than the second eccentricity detecting portion width, and the tracking error detecting means being the guide groove or wobbling on the optical disc. 5. An optical recording / reproducing apparatus including an optical recording / reproducing apparatus including a circuit and a mechanism for detecting a deviation amount of an optical focus from a center position of a track made of pits, a buffer memory, and an sine wave output circuit and an eccentricity detector according to claim 4. Will be solved by.

[0010]

【Example】

(Embodiment 1) The present invention will be described in detail below with reference to the drawings. Figure 1
FIG. 3 is a block diagram of an optical recording / reproducing apparatus for realizing the optical recording / reproducing method of the present invention. The optical head 101 of FIG. 1 has a light source that generates recording or reproducing light. The light source emits laser light, and is, for example, a gas laser or a semiconductor laser. Further, the optical head includes a radial actuator 105 for moving the focal position in the radial direction of the disk by moving the objective lens, a focus actuator for moving the focus position in the depth direction of the disk, a tracking error detector and a focus error detector. The laser light passes through the optical system in the optical head and is applied to the disk. The reflected light passes through the optical system again and enters the light receiving element. As a light receiving element, for example, a PIN photodiode is obtained as a current signal. This current signal is converted into a voltage signal by the IV conversion circuit in the amplifier 106, and then further amplified by the amplifier. This signal is proportional to the change in the amount of reflected light when the optical disk is a disk that consists of embossed pit rows that use the diffraction effect due to the depressions on the substrate or a phase change disk, and in the case of a magneto-optical signal, the differential of the split photodetector It is a signal proportional to the signal. Next, a waveform equalizer 107 performs waveform equalization processing. The waveform equalization here is, for example, a delay circuit for each frequency component of the signal obtained by passing an input signal in parallel with a bandpass filter having a transmission band in a plurality of different frequency bands. And to increase the signal density by the method of synthesizing each frequency component again after changing the time delay and the strength by the resistance. Then the demodulator at 108
It performs two functions of binarization and demodulation. The binarization includes peak value detection and threshold value detection. The error detection circuit 109 also performs error detection simultaneously with demodulation. FIG. 2 shows a block configuration of the optical disc. Each block has
Block address 201, data 202, CRC (Cyclic Redundancy Che) 203
ck). Error detection is performed by CRC. The data of the block in which no error has been detected is stored at a predetermined address in the buffer memory 110 based on the address information.

In the present invention, recording and reproduction are performed without tracking. Here, the non-tracking operation is an operation in which the tracking operation is not performed when the optical disc is rotated to perform the recording / reproducing, and the recording / reproducing is performed while the optical focus is moved in the radial direction in a constant feed amount or in a stepwise manner per revolution. Refers to doing. When the optical focus is moved by a constant feed amount, the recording track is formed continuously in a spiral shape or the recording track in a spiral shape is continuously reproduced. In the case of moving in the radial direction, forming recording tracks in concentric circles, reproducing concentric recording tracks,
Alternatively, it corresponds to the access of the spiral track.

When the recording track is formed along an embossed pit or guide groove provided spirally or concentrically on a disc, the center of the embossed pit or guide groove, the center of the recording track, the optical disk and the rotation axis. Normally, the center of the center hole of the optical disc for connecting the optical disc does not exactly match, and eccentricity occurs. When the reproducing light is emitted without tracking, the center of the track coincides with the center of the rotation axis, and the recording track coincides with the center of the embossed pit or the guide groove as described above. The tracks intersect with each other. This is shown in FIG. Reference numeral 301 is a recording track, and 302 is a locus of the reproduction light focus. When the reproduction light focus is at the center of the track, errors mainly due to defects are increased, but errors due to crosstalk increase as the distance from the center of the track increases. It has been described above that this error is detected by the error detection circuit and only the block having no error is stored in the buffer memory. If the feed amount of the reproduction light per revolution is set to be equal to or greater than the recording track pitch, the location where a crosstalk error occurs will not be reproduced again unless the access is made again, but it is set to less than the recording track pitch. Then, reproduction can be performed again at a position less than the recording track pitch from the position irradiated when the crosstalk occurred before. Specifically, if the distance from the track center of 303 is set to off-track based on FIG. 3 and the maximum off-track amount that does not cause crosstalk error is Xa, if the feed amount of the reproduction light per revolution is within 2Xa, Even if a crosstalk error occurs, it can be reproduced without causing a crosstalk error in a different rotation, the crosstalk error can be excluded, and the data of the entire disc can be reproduced with only the remaining data. In addition, when the feed amount of the reproduction light per revolution is constant and the eccentricity is sufficiently large with respect to the track, R = Xa / Wp
The relationship of × 100 has become true. Here, R (%) is a length that does not cause a crosstalk error in one round of the reproduction light / a length of one round, Xa: an allowable off-track that does not cause a crosstalk error, and a Wp track pitch. R does not depend on eccentricity.

As a method of storing data in the buffer memory, a method of storing the blocks in the order of reading the blocks, in the memory in the order of memory addresses, and with the block addresses can be considered. However, when reading from the buffer memory, it is necessary to search for the block address and output the data in the order of the addresses, so that it takes a long time to read and a heavy load is imposed on the system. It is also conceivable to simultaneously write the data in the buffer memory in the order of the memory addresses and at the same time create a collation table of the buffer memory addresses and the block addresses separately and write them in a region other than the data area in the buffer memory. Considering the process of searching the collation table when outputting from the buffer memory, the block address order in the collation table is preferably the block address order of the optical disk. However, since this also collates the collation table with the data area at the time of reading, it takes time to read as in the above case, which is not preferable because the burden on the system is large. Therefore, by writing block information in a buffer memory according to a block address, as described in FIGS. 4 and 6 of JP-A-3-178094, which is a known example of a rotary head type recording / reproducing apparatus,
The method of reading the information in time series by reading the reading of the buffer memory in the order of the buffer memory address was selected. The read control unit 112 performs this operation.
Output to the drive interface.

However, in order to obtain continuous data in time series in the buffer memory, it is necessary to move at least the eccentric portion of the reproduction light focus in the radial direction. The above R does not depend on the eccentricity, so that the buffer memory capacity increases almost in proportion to the eccentricity.

Here, attention is paid to the frequency component of the track shake. The recording track can be regarded as a circular shape as well as a concentric circle, and even if it is spiral, the track pitch is small. When the rotation of the central axis of the spindle is stable and the shape of the recording track is not distorted, the track runout can be described as a single frequency sine wave having an eccentric amplitude as the fundamental frequency of the spindle rotation. Of course, from the above-mentioned conditions, the track shake has a component with a frequency equal to or higher than the fundamental frequency, but the fundamental frequency component during the track shake is large. Therefore, by reducing only this fundamental frequency component, the eccentricity can be greatly reduced in a pseudo manner. Its basic configuration is to detect the eccentricity of the disc and proportionally
This is to output a sine wave having a fundamental frequency according to the rotation speed of the spindle to the radial actuator. An area where a tracking error can occur, such as a guide groove or a wobbling pit, is provided in the optical disc, and the optical focus is moved to that area. Therefore, the tracking error signal generation circuit 102 generates a tracking error signal. The eccentricity detector 103 detects the phase of the fundamental frequency component according to the eccentricity and the spindle speed from the tracking error signal. For example, when the tracking error signal is a push-pull signal generated by the guide groove, the eccentricity can be detected by counting the number of waves during one rotation of the spindle and the number of zero-crossing points during one rotation. The phase is obtained by comparing the fundamental frequency component of the tracking error signal with the spindle rotation signal. In another example, tracking is performed while the coarse motor is stopped, and the information is obtained from the drive signal of the objective lens at that time. Alternatively, it can be obtained from the relative position of the objective lens with respect to the optical head position detected by attaching the electrostatic capacitance position sensor to the driven portion of the objective lens or the objective lens mounting portion with the coarse movement motor stopped. . In addition, in a state where the position of the objective lens with respect to the position of the optical head is fixed, the optical head is driven by the coarse movement motor, and it is obtained from the drive signal. In the method of detecting the amplitude and the phase of the eccentricity by driving the objective lens or the optical head, the tracking is performed with sufficient accuracy so that the reproduction can be performed by tracking the optical focus or the recording can be performed by performing the tracking. No need.
The sine wave generation circuit 104 has an amplitude proportional to the eccentricity with respect to the eccentricity and the phase signal obtained in the eccentricity detector, the difference between the fundamental wave component of the tracking error signal and the phase is constant, and the phases are equal or half. This is a circuit that outputs a sine wave with a wavelength shift. The sine wave is output to the radial actuator 105 and artificially reduces the eccentricity. Negative feedback is applied to the eccentricity and the sine wave amplitude detected by the tracking error signal generating circuit, and the sine wave amplitude is determined so as to minimize the eccentricity in a pseudo manner.

If it is possible to drive the optical head by following the basic frequency of track shake by the coarse motor,
The above-mentioned sine wave can be output to the coarse movement motor to suppress the track shake. In this case, the radial actuator is not required when only non-tracking reproduction is performed.

From the above, the required buffer memory capacity can be greatly reduced. For example, eccentricity is originally 5
If the number of 0 tracks is reduced to 2 tracks in a pseudo manner, the buffer memory capacity required by simple estimation is 1/25. Further, when the frequency band of the tracking system is limited to the basic frequency band, it is used only for suppressing the basic frequency component of the tracking error during non-tracking, and the tracking actuator can be driven only in the low band.

On the other hand, when the guide groove on the optical disk is not used for tracking error detection but is used only for the purpose of suppressing the radial expansion of the recording magnetic domain in a magneto-optical disk, for example, the guide groove is used for tracking. Although there are wobbling pits and wobbling pits, if the tracking error signal is not sufficient for tracking, whether to perform non-tracking playback based on the strength of the tracking error signal generated from the tracking error signal generation circuit The write control unit 113 is a circuit for determining whether or not to perform reproduction. Although not shown, the write control unit determines the disc type of the optical disc to be inserted into the drive based on the disc type information in the optical disc, and determines whether the disc is a non-tracking reproduction optical disc or a tracking reproduction optical disc. To do. Further, the writing control unit instructs the above-mentioned data transfer processing to the buffer memory when performing non-tracking, and when performing the tracking reproduction,
Instructs not to perform transfer processing to the buffer memory.

Further, since the data is output from the drive interface at a constant transfer rate, if the spindle rotational speed and the data transfer rate deviate from each other by a small amount, the information in the buffer memory becomes insufficient or full. Will be lost. In order to prevent this, the amount of information in the buffer memory is constantly monitored, and the number of revolutions of the spindle motor 115 is controlled by the amount of information in the buffer memory. 1
The spindle motor control unit 14 monitors the continuous data amount without crosstalk error in the buffer memory,
When there is insufficient continuous data, increase the rotation speed, and when there is too much data, decrease the rotation speed. The coarse motion motor control unit 116 has a function of adjusting the feed amount of the optical head according to the fluctuation of the spindle motor rotation speed. The feed amount of the optical head is proportional to the rotation speed of the spindle motor,
A drive signal is output to the coarse movement motor 17 in FIG.

The non-tracking method has various advantages over the conventional tracking method. First, in the tracking method, since the optical focus needs to be accurately aligned with the recording track, the cutoff frequency of the tracking servo system becomes high, which may burden the system. In particular, the narrower track that accompanies the higher density of the disk leads to a decrease in push-pull signal strength.To compensate for this, the track actuator is made more sensitive, the movable optical system is made lighter, the disk is made highly reflective, and the guide groove is made The burden on the entire system increases due to difficulty in shape control. The non-tracking method can solve the above problems.

(Embodiment 2) Next, an embodiment of a read-only disc using the present invention will be described. FIG. 4 is a schematic diagram of an optical disc in which embossed pits are formed spirally on the entire surface of the disc, and is a read-only disc. 401
In the disk of 4 becomes the connecting part with the spindle at the center 4
02 center holes are provided. The data area 403 is provided with embossed pits 404, and the embossed pit row is schematically shown. Since the embossed pits are formed fine enough for the servo band, the embossed pit row has the same function as the guide groove. When light is emitted from the optical head, the push-pull signal can be detected anywhere in the data area of the disc. Tracking may be performed by this push-pull signal. Regarding the switching method between the non-tracking and the tracking, the method using the writing controller is described in the first embodiment. The non-tracking method is particularly effective when the embossed pit shape is restricted with the progress of higher density and the push-pull signal strength is not sufficient for tracking.

The optical disc used has a pitch of 1.6 μm and the data format is shown in FIG. SM of 501 is a sector mark, VFO of 502 is a continuous data pattern for PLL lock, ID of 503 is a track number and sector number, BA of 504 is a block address, DATA of 505 is a data area, and CRC of 506 is an error correction code. And 507 is a block.

The access sequence in the non-tracking reproduction will be described. First, the coarse movement motor is moved to the vicinity of the target track, then the laser light is emitted, the focus is adjusted, and the PL is adjusted.
L synchronization, ID reading. When it is far away from the target track, the coarse movement motor moves to a position closer to the target track position. At this time, the PLL is still in focus.
The synchronization is performed again and the ID is read. The data reproduction is started at a number smaller than the target track and within a certain number of distances from the target track. At the time of reproduction, the coarse movement motor is fed at a substantially constant feed in accordance with the spiral pattern of the recording track, and the objective lens is driven by a sine wave so as to remove the basic component of eccentricity as described in the first embodiment.

As a comparative example, tracking servo was performed on the same disk by the push-pull method instead of non-tracking. Here, first move to the vicinity of the target track with a coarse movement motor, then emit laser light, focus focus,
Tracking execution, PLL synchronization, ID reading, when it is far away from the target track, it is moved to a position closer to the target track position by the coarse movement motor. At this time, the focus is in focus and the tracking is still in execution. Although the execution may be stopped, in this example, the execution is continued. Next, a pulse is inserted every one rotation of the disc, a track jump is performed to move to a target track position, and reproduction is started.

FIG. 6 shows the change in the error rate with respect to the track feed amount for each rotation during non-tracking reproduction.
The smaller the track feed amount, the lower the error rate because the reproduction light track reproduces the recording track more closely. It increases as the track feed amount increases, and sharply rises when the track feed amount is 0.5 μm or more and less than 0.6 μm. If the linear velocity and the linear density are the same, the track feed amount is simply inversely proportional to the transfer speed. Therefore, as the track feed amount increases, the error rate increases, but the transfer speed increases. Therefore, it is desirable to select the highest track feed amount with an error rate within an allowable range.

On the other hand, the error rate at the time of executing tracking in the comparative example was 10 −6.3.

(Embodiment 3) Next, an embodiment of a recordable and reproducible disc will be described. FIG. 7 shows a recordable / reproducible disc. A recording film is formed in the recording area of the disc. As the recording film, for example, a magneto-optical film, a phase change film, a shape memory film or the like can be used. Here, a magneto-optical magnetic film is used. 702 for circular disc 701
A central hole is provided for connection with the spindle motor.

At the time of recording, first, the optical head is moved by the coarse movement motor so that the light is irradiated onto the first eccentricity correction area 703, and then the light irradiation and focus focusing are performed. First
In the eccentricity correction area, a guide groove, a wobble pit, or the like is formed as a tracking error generating means. In particular, the guide groove is formed here. A push-pull signal is obtained as the diffracted light from the guide groove. By setting the width of the first eccentricity correction area in the radial direction to be equal to or greater than the eccentricity of the disk, a continuous tracking error signal can be obtained. The tracking error signal generation circuit 102 in FIG. 1 detects the eccentricity and the phase of the tracking error signal as described in the first embodiment, and the sine wave generator 104 reduces the basic signal component of the eccentricity. Since the guide groove is used not for tracking but for reducing only the basic signal component of eccentricity, the push-pull signal strength may be lower than that for tracking. Next, the optical focus is moved to the second eccentricity correction area 704 that is closest to the recording position.
A guide groove and a sector head are provided in the second eccentricity correction area. The second eccentricity correction area is necessary for suppressing the eccentricity of the recording tracks on the entire surface of the disk during recording, and for reducing the number of recording tracks traversing the reproduction track during reproduction. It reduces the fundamental wave component of eccentricity that cannot be compensated for in the eccentricity correction range, and is not always necessary. Since the eccentricity has already been suppressed in the first eccentricity correction area, the optical focus does not significantly cross the track per turn in the second eccentricity correction area. Therefore, the radial width of the second eccentricity correction area can be made smaller than that of the first eccentricity correction area. In addition to the eccentricity correction, a sector head 705 is provided in the second eccentricity correction area to detect and synchronize the sector address and the track address. After that, the optical focus is moved to the data area 706 and recording is performed while moving the optical head at a constant feed by the coarse movement motor while driving the radial actuator with a sine wave. The data area is required for recording and reproduction. The synchronization information is provided radially as a VFO pattern of the sector head as an embossed pit row. Playback is possible at any radial position. In addition, as shown in FIG.
Recording is performed by adding every 7 blocks.

The operation during reproduction is not much different from that during recording. First, eccentricity correction is performed in the first eccentricity correction region, and then further eccentricity correction is performed in the second eccentricity correction region, and then reproduction is performed. The regeneration procedure was described in Example 1.

(Embodiment 4) FIG. 8 shows a Japanese Patent Application No. 4-15647.
1 is a schematic diagram of an optical disc using the magneto-optical recording medium described in Japanese Patent Publication No. A circular disc of 801 is provided with a central hole of 802. A guide groove or a wobbling pit is provided in the eccentricity correction area 803 for detecting a tracking error signal. Here, in particular, a guide groove is provided. The super-resolution reproduction area 804 is an area where the above-mentioned prior art medium is provided. FIG. 9 is a schematic cross-sectional view of 804 in the radial direction.
A transparent substrate 901 has a first dielectric layer 902, a magneto-optical recording layer 903, a second dielectric layer 904, a first heat absorbing layer 905, a heat blocking layer 906, and a second heat absorbing layer 907. Has been formed. Here, the first dielectric layer and the second dielectric layer are not always necessary. The information consists of the presence or absence of a heat barrier layer. At the time of reproduction, the direction of magnetization of the magneto-optical recording film is constant before light irradiation, but the temperature rise caused by light irradiation differs depending on the presence or absence of the heat blocking layer or the change in layer thickness.
For example, in a magnetic film for Curie point recording, the heat flow with the heat absorbing layer is blocked by the heat blocking layer in a portion of the heat blocking layer,
The temperature reaches a higher temperature than in the area without the heat blocking layer, and the magnetization is reversed near the Curie temperature. The reached temperature is low in the part without the heat blocking layer, and the magnetization does not reverse. By causing this in the beam spot of the reproducing light, it is possible to effectively increase the optical transfer function. The guide groove in the eccentricity correction region includes the first dielectric layer, the magneto-optical recording layer, the second dielectric layer,
The heat blocking layer is formed in a spiral shape without forming the first heat absorbing layer, and the second heat absorbing layer is formed thereon. The heat blocking layer is transparent, and a push-pull signal can be detected by forming a material that reflects light, such as Au, Pt, Al, or Ag, as the second heat absorbing layer.

As described above, it is necessary to align the heat blocking layer formed on the side opposite to the reading side with the guide groove provided on the reading side, which makes tracking difficult. Therefore, the non-tracking method is particularly effective.

Similar to the method described in the first and third embodiments, the reproducing method first irradiates the eccentricity correction unit 803 with light to correct the eccentricity, and then performs non-tracking in the super-resolution reproduction area 804. Play.

[0033]

As described above, according to the present invention, recording / reproducing is performed by non-tracking, thereby reducing the load on the drive and realizing high density without applying high-precision fine processing to the optical disk. . By reducing the deviation by outputting a sine wave of the spindle rotation frequency to the radial actuator, the buffer memory capacity is greatly reduced. Drive unit price can be kept low. Further, it is particularly effective for a medium in which it is difficult to form a guide groove or wobbling pit and an information string in a mixed manner.

[Brief description of drawings]

FIG. 1 is a block diagram of an optical recording / reproducing apparatus that realizes an optical recording / reproducing method of the present invention.

FIG. 2 is a block diagram of an optical disk block.

FIG. 3 is a diagram showing a relationship between a recording track and a reproduction light locus.

FIG. 4 is a schematic diagram of an optical disc including an embossed pit information string.

FIG. 5 is a block diagram of a sector of an optical disc.

FIG. 6 is a diagram showing track error dependence of error rate.

FIG. 7 is a schematic view of a recordable / reproducible optical disc of the present invention.

FIG. 8 is a schematic diagram of a super-resolution optical disc.

FIG. 9 is a schematic sectional view of a super-resolution optical disc.

[Explanation of symbols]

 103 ... eccentricity detector 104 ... sine wave generator 110 ... buffer memory 201 ... block address

Claims (10)

[Claims] 1. An optical recording / reproducing method using an optical recording / reproducing apparatus for recording / reproducing information on / from an optical disc and for roughly moving an optical head in a radial direction, and an optical recording / reproducing device having a tracking error detecting means. An optical recording / reproducing method characterized by performing non-tracking. 2. A drive means for driving recording and reproduction for an optical disk capable of recording and reproducing and reproducing for an optical disk capable of reproducing only, and scanning the optical focus in the radial direction. An optical recording / reproducing method comprising: forming or reproducing a spiral recording track by moving the recording medium at a constant speed. 3. The optical recording / reproducing method according to claim 1, wherein the eccentricity detecting portion on the optical disk is irradiated with light to detect track shake, and the amplitude and phase of the fundamental frequency component of the track shake is detected by an eccentricity detector. However, a sine wave having the same fundamental frequency as the track shake and a constant phase difference from the track shake is output by a sine wave output circuit to reduce the deviation of the optical focus position with respect to the recording track. Optical recording and reproducing method. 4. The optical recording / reproducing apparatus according to claim 3, wherein the optical recording / reproducing apparatus has a driving means for coarsely moving the optical head in the radial direction, a driving means for finely moving the objective lens in the radial direction, and a tracking error detecting means. An optical recording / reproducing method characterized in that the objective lens is driven by a radial actuator with the sine wave. 5. The optical recording / reproducing method according to claim 3, wherein an optical recording / reproducing apparatus having a driving means for roughly moving an optical head in a radial direction and a tracking error detecting means is used, and the sine wave is a drive signal of the driving means. An optical recording / reproducing method, characterized in that the optical head is driven so as to be superposed on the optical recording medium. 6. The optical recording / reproducing method according to claim 1, wherein the recording track is divided into a plurality of blocks, and each block includes a block address, an error detection code and data.
At the time of reproduction, the block address signal and the data in the block are reproduced, and the error detection code is used for error detection. If the error detection is good or bad, if the error detection is good, the predetermined address of the buffer memory corresponding to the block address An optical recording / reproducing method characterized in that block data is transferred. 7. The optical disc, wherein the eccentricity detecting portion comprises a guide groove or a wobbling pit, is provided at a plurality of locations in the optical disc, and the first eccentricity detecting portion width is larger than the second eccentricity detecting portion width. . 8. An optical recording / reproducing apparatus, wherein the tracking error detecting means comprises a circuit and a mechanism for detecting a deviation amount of an optical focus from a center position of a track formed by a guide groove or a wobbling pit on an optical disk. . 9. An optical recording / reproducing apparatus including the buffer memory according to claim 2, the sine wave output circuit according to claim 4, and an eccentricity detector. 10. A magneto-optical recording film, a heat absorbing layer, and a heat blocking layer, which are binary depending on the presence or absence of the heat blocking layer between the heat absorbing layer and the magneto-optical recording film or a change in layer thickness. Of the optical disc, the optical disc has an eccentricity detection section and a super-resolution reproduction area, and the eccentricity detection section is formed on a transparent substrate in the order of a heat shield layer and a second heat absorption layer. The optical disc characterized in that the super-resolution reproducing region is formed by sequentially forming a heat-shielding layer, a first dielectric layer, a magneto-optical recording layer, a second dielectric layer, a heat-shielding layer, and a heat-absorbing layer on a transparent substrate.