JP2004047100A - Method for determining optimum recording and reproducing light quantity for optical recording medium, and recording and reproducing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for recording and reproducing a land/groove magneto-optic recording medium which respectively records and reproduces data on/from the land/groove magneto-optic recording medium with an optimum recording light quantity and reproducing light quantity. <P>SOLUTION: For example, in a recording data on groove parts of both sides of a land part, a plurality of reproduced signals obtained by combinations of various recording light quantity and reproducing light quantity not only by modulating the recording light quantity into various values but also by modulating the reproducing light quantity in reproducing the land parts into various quantity are obtained, and a combination of optimum recording light quantity and optimum reproducing light quantity for minimizing an error rate is determined among the plurality of reproduced signals. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a method for determining an optimum recording light amount and a reproducing light amount for an optical recording medium, and more particularly, to a method for determining an optimum recording light amount and a reproducing light amount for a land-groove type optical recording medium, and using the determining method. And a recording / reproducing method for a land-groove type optical recording medium.

(4) In the magneto-optical recording medium, a multilayer film including at least one layer of a magnetic recording film and a reflective film is formed on a transparent substrate via an insulating film. The substrate has grooves and prepits formed in the track direction in advance by injection molding, and lands (convex portions) are defined between the grooves. The land has a data recording area for recording information and a header area in which address signals and the like are recorded in the form of pre-pits. Since the groove functions as a guide groove for tracking the optical head, no information is recorded.

With the recent increase in the amount of information processing, an optical recording medium capable of high-density recording is required. A so-called land-groove type in which a groove is formed as a wide groove and information is written not only in a land portion but also in the groove. Have been devised.

In the case of a land-groove type magneto-optical recording medium, the track pitch is as narrow as 0.5 to 0.8 μm, and information is also recorded in the groove portion. It is necessary to form each track in a land portion and a groove portion with an optimum size. If the recording power is overpower, the domain recorded in the groove (or land) is formed to extend to the adjacent land (or groove), and the information recorded in the adjacent track is destroyed. (Cross light / cross erase) On the other hand, if the recording power is underpower, the domain becomes smaller than the track width, so that the S / N of the reproduced signal is reduced. Furthermore, since the land portion and the groove portion have different focus positions, the optimum recording light powers are different, and it is desirable to adjust each independently.

光 By the way, since magneto-optical recording is heat mode recording, even if recording is performed under the same recording conditions, the size of the recording magnetic domain changes due to the influence of the recording device temperature and the medium temperature. Therefore, it is necessary to perform recording while feeding back the influence of the recording apparatus temperature and the medium temperature to the recording conditions. In addition, variations in recording devices due to differences in light spot shapes due to aberrations and defocusing of the optical head, differences in characteristics of laser light sources, and variations between lots of recording media, etc., also greatly affect recording conditions.

The present inventors have disclosed in Japanese Patent Application No. 8-118494 a test signal before actual recording in order to obtain a magnetic domain of a fixed size irrespective of a difference in recording conditions due to various factors as described above. Has been disclosed by trial writing with various recording laser powers and reproducing the same to determine the optimum power of the recording light. In this method, while increasing or decreasing the laser light power or the laser light pulse width, a laser light pulse having a period T1 is recorded under application of a magnetic field having a polarity corresponding to the test data so that the magnetic domains to be recorded do not overlap each other. The isolated magnetic domain group and the continuous magnetic domain group are formed by irradiating a laser beam pulse having a period T2 at which the magnetic domains overlap each other. Next, the magnetic domain groups are reproduced to obtain a difference Δ1 between the average values of the reproduced signals, and a laser light power or a laser pulse width corresponding to Δ1 closest to the reference value Δ0 is selected. A magnetic domain width adjusted by performing optical magnetic field modulation recording using the selected laser light power or laser light pulse width is formed on the track.

As described above, even in a land-groove type magneto-optical recording medium in which it is necessary to form magnetic domains with optimal sizes in the land portion and the groove portion, test writing is performed by some method to optimize the power of recording light and the like. It is desirable. Furthermore, in the area where test writing is performed, there is a portion where recording is performed with a recording laser having a higher output than the normal user data area. The recording characteristics of the area where writing is performed change. For this reason, the recording conditions obtained from the test writing may not reflect the optimum conditions of the recording area where the actual recording is performed.

再生 Further, as one of the techniques for achieving the high density of the magneto-optical recording medium, a reproducing method using magnetic super-resolution is known. In this method, only one minute magnetic domain can be detected by utilizing the temperature distribution of the mask layer laminated on the recording layer. However, since the size of the mask of the mask layer changes depending on the power of the reproduction light, unless the power of the reproduction light is optimized, the S / N is reduced, and high resolution by magnetic super-resolution cannot be obtained. Therefore, when magnetic super-resolution is used for a land-groove type magneto-optical recording medium, it is necessary to precisely control not only the recording power but also the reproduction power.

A first object of the present invention is to provide a method for determining an optimum recording light amount for preventing a cross write during recording on a land-groove type optical recording medium. A second object of the present invention is to provide a recording method and a recording / reproducing apparatus for a land / groove type magneto-optical recording medium for recording on a land / groove type magneto-optical recording medium with an optimum recording light amount.

Further, a third object of the present invention is to provide a method for determining an optimum recording light amount for preventing cross-write at the time of recording on a land-groove type optical recording medium and improving S / N at the time of reproduction. is there. A fourth object of the present invention is to provide a recording / reproducing method and a recording / reproducing apparatus for a land / groove type magneto-optical recording medium for recording / reproducing a land / groove type magneto-optical recording medium with optimum recording light amount and reproducing light amount, respectively. It is in.

A fifth object of the present invention is to provide a method capable of preventing an excessive use of an area for performing test writing and reliably determining an optimum recording light amount and / or an optimum reproduction light amount by test writing. is there.

According to an aspect of the present invention, there is provided a method of determining an optimum recording and reproducing light amount of a land-groove type optical recording medium,
A first step of recording test patterns with different recording light amounts in a plurality of areas of a land portion or a groove portion,
A second step of recording test patterns with different recording light amounts in a plurality of regions of the groove or land adjacent to both sides of the plurality of regions of the land or groove;
A third step of reproducing the plurality of test patterns recorded in the first step with various reproduction light amounts,
The reproduction light amount from an area that provides the reproduction signal with the least error among the plurality of reproduction signals with various reproduction light amounts from the plurality of test patterns reproduced in the third step is determined as the optimum reproduction light amount, and the reproduction signal with the least error And a fourth step of setting a recording light amount recorded in an area that produces the optimum recording light amount to a method for determining an optimum recording and reproducing light amount of a land-groove type optical recording medium.

In the aspect of the present invention, for example, when recording the groove portions on both sides of the land portion, not only the recording light amount is modulated to various values, but also the reproduction light amount when reproducing the land portion is modulated to various amounts. Thus, a plurality of reproduction signals obtained by various combinations of the recording light amount and the reproduction light amount are obtained, and a combination of the optimum recording light amount and the optimum reproduction light amount that minimizes the error rate among the plurality of reproduction signals is determined. . Further, in this method, not only the recording light amount but also the reproducing light amount can be simultaneously optimized, so that the magneto-optical recording medium using the magnetic super-resolution reproducing method in which the resolution and the S / N change significantly depending on the amount of the reproducing light. It is very suitable for

In the fourth step, errors of reproduction signals from the test patterns recorded and reproduced by various combinations of the recording light amount and the reproduction light amount reproduced in the third step are obtained, and the error is determined for every reproduction light amount. The optimum reproduction light amount is defined as the reproduction light amount having the smallest error total, and the recording light amount that generates the reproduction signal having the least error among the reproduction signals reproduced at the optimum reproduction light amount is calculated as the optimum recording light amount. By doing so, the optimum reproduction light amount and the optimum recording light amount can be determined. In the fourth step, the power margin of the reproduction light can be maximized by using such a determination method.

Alternatively, in the fourth step, errors of reproduction signals from the test patterns recorded and reproduced with various combinations of the recording light amount and the reproduction light amount reproduced in the third step are obtained, and the errors are determined for each recording light amount. By summing over all reproduction light amounts, the recording light amount with the smallest error total is set as the optimum recording light amount, and a reproduction signal with the least error is generated from the reproduction signals from the test pattern recorded with the optimum recording light amount. By setting the reproduction light amount to the optimum reproduction light amount, the optimum recording light amount and the optimum reproduction light amount can be determined. By employing such a determination method in the fourth step, the power margin of the recording light can be maximized.

In the present invention, in the first step, the land portion or the groove portion of the n-th track is divided into B areas, and the recording light amount Pw (n, m) to be recorded in the m-th area (0 ≦ m ≦ B) = P0 + mΔ (where P0 is the recording light amount recorded in the area of m = 0, Δ is the change rate of the recording light amount), and in the second step, the grooves of the (n + 1) th and (n-1) th tracks Section or land area is divided into B areas, the recording light amount Pw to be recorded in the m-th area (0 ≦ m ≦ B) of the (n + 1) -th track is Pw (n + 1, m) = P0 + mΔ, and It is preferable that the recording light amount Pw to be recorded in the m-th area (0 ≦ m ≦ B) is Pw (n−1, m) = P0 + mΔ. Further, in the first step, each area includes a plurality of sectors, the plurality of sectors in the same area are recorded with the same recording light amount, and in the fourth step, the number of sectors in which the number of errors in the sector does not exceed the reference value. It is preferable that the total reproduction S (Pr) of the areas reproduced with the same reproduction light amount is determined as the optimum reproduction light amount.

In the method according to the aspect of the present invention, the optical recording medium has a plurality of areas for recording the test pattern, and when recording a test pattern, one test pattern recording area is selected from the plurality of test pattern recording areas. For this purpose, it is preferable to store auxiliary information in an area different from the test pattern area. This prevents deterioration of the same test pattern recording area due to excessive use.

According to the present invention, it is preferable that the auxiliary information includes information that can determine whether or not recording in each test pattern recording area is permitted. Further, it is preferable that the auxiliary information includes the number of times of recording using a test pattern recording area in which test pattern recording is permitted. Further, when the number of times of recording the test pattern using the test pattern recording area where the recording of the test pattern is permitted is larger than a preset number, the further number of the test pattern recording area is further increased. It is preferable to rewrite the auxiliary information so that writing is not allowed. If the number of times a test pattern has been recorded using a test pattern recording area where the recording of the test pattern is permitted is greater than a preset number, another test pattern has not been recorded in the past. The auxiliary information may be rewritten so that the recording of the test pattern can be permitted as a new test pattern recording area using the recording area of the test pattern.

According to the present invention, a plurality of test pattern recording areas may be provided on the same track. Further, a plurality of test pattern recording areas may be provided on the same sector.

In the method of the present invention, the recording light amount can be adjusted to various light amounts by changing the power of the recording light or the pulse width of the recording light. Changing the pulse width of the recording light includes dividing the recording light into a plurality of pulses when recording one recording mark and changing the pulse length of one recording light pulse.

According to the present invention, there is provided a land / groove type optical recording medium recording / reproducing method for recording / reproducing information with the recording light amount and the reproduction light amount determined by the method according to the above aspect. In the present invention, it is desirable that the optical recording medium is a magneto-optical recording medium that is reproduced by magnetic super-resolution.

Hereinafter, embodiments and examples of the present invention will be specifically described with reference to the drawings.

FIG. 1 shows an outline of a recording / reproducing apparatus (drive) that can be used for a method for determining the optimum recording light power and reproducing light power of a land-groove type magneto-optical recording medium. This device includes a laser control system for irradiating a pulsed light with a constant period synchronized with code data to a land-groove type magneto-optical disk 21 described later, and a magnetic field control for controlling a magnetic field applied to the magneto-optical disk 21. It mainly comprises a system, a signal detection system for detecting signals from the magneto-optical disk 21, and a drive controller 320 for controlling those control systems. In the laser control system, the laser 22 is connected to a laser drive circuit 32, and the laser drive circuit 32 controls the laser 22 in response to a clock signal described later from a PLL circuit 39. In the magnetic field control system, a magnetic coil 29 for applying a magnetic field is connected to a magnetic coil driving circuit 34. The magnetic coil driving circuit 34 receives input data from an encoder 30 to which data is input through a phase adjustment circuit 31 and receives magnetic data. The coil 29 is controlled.

In the signal detection system, a first polarizing prism 25 is disposed between the laser 22 and the magneto-optical disk 21, and a second polarizing prism 251 and detectors 28 and 281 are disposed beside the first polarizing prism 25. The detectors 28 and 281 are connected to a subtractor 302 and an adder 301 via I / V converters 311 and 312, respectively. The adder 301 is connected to the PLL circuit 39 via the clock extraction circuit 37. The subtractor 302 is connected to the decoder 38 via the reproduction signal detection circuit 33.

The drive controller 320 includes a clock source 322 and a test data timing generation circuit 324, and the test data timing generation circuit 324 generates a sample hold pulse and a timing pulse described later.

In the above-described apparatus configuration, the light emitted from the laser 22 is made into parallel light by the collimator lens 23, and is condensed on the disk 1 by the objective lens 24 through the polarizing prism 25. The reflected light from the disk 21 is directed to the polarizing prism 251 by the polarizing prism 25, passes through the half-wave plate 26, and is split into two directions by the polarizing prism 251. The split light is condensed by a detection lens 27 and guided to photodetectors 28 and 281, respectively. Here, pits for generating a tracking error signal and a clock signal are formed on the disk 21 in advance. After the signal indicating the reflected light from the clock signal generation pit is detected by the detectors 28 and 281, the signal is extracted by the clock extraction circuit 37. Next, a data channel clock is generated in PLL circuit 39 connected to clock extraction circuit 37.

At the time of data recording, the laser 22 is optically modulated at a constant frequency by a laser driving circuit 32 so as to synchronize with a data channel clock, emits a continuous pulse light having a small width, and occupies a data recording area of the rotating disk 21. Heat locally to the interval. The data channel clock controls the encoder 30 of the magnetic field control system to generate a data signal having an integral multiple of the reference clock cycle. The data signal is sent to the magnetic coil driving device 34 via the phase adjustment circuit 31. The magnetic coil driving device 34 controls the magnetic field coil 29 to apply a magnetic field having a polarity corresponding to the data signal to a heated portion of the data recording area.

FIG. 2 shows an example of the structure of the magneto-optical disk 21. The magneto-optical disk 21 is a land-groove type magneto-optical disk having a wide groove portion 114 and a magnetic domain 110 formed in both the land portion 112 and the groove portion 114. On the substrate 101, a laminated portion 103 including a dielectric layer, a recording layer exhibiting a magneto-optical effect, a dielectric layer, a reflective layer, and a protective layer is usually formed. The configuration of each layer is omitted).

In this embodiment, a test signal is recorded by irradiating the land-groove type magneto-optical disk 21 shown in FIG. 2 with laser beams of various recording light powers using the recording / reproducing apparatus (drive) shown in FIG. A description will be given of a method of determining the optimum recording laser power for each of the land portion and the groove portion by reproducing them (test writing) and reproducing them.

[First step: Setting of temporary recording light power for trial writing]
First, the land / groove type magneto-optical disk 21 is mounted on the recording / reproducing apparatus shown in FIG. 1, and after rotating, the optical head including the laser 22 is placed on the track (n-th track) of the land portion where the test writing of the test pattern is performed. And a magnetic head including the magnetic coil 29 is positioned near the track. Next, the test signal is recorded by irradiating a laser beam while applying an external magnetic field to the disk 1 in accordance with the recording external magnetic field and the recording laser pulse for the test signal shown in FIG.

(3) When actually recording a recording signal in the optical magnetic field modulation recording method, a laser beam is emitted at every recording clock as shown in a magnetic domain group 65 in FIG. 3 to form a magnetic domain array overlapping each other. In this embodiment, in order to record a test signal for determining an appropriate recording light power (test writing), the cycle of laser emission is adjusted so that the recording clock is thinned out, and isolated short magnetic domains are recorded in the test signal recording track area. 64 (hereinafter, referred to as isolated magnetic domains 64) (the left side of the magnetic domain pattern in FIG. 3). The interval between the isolated magnetic domains 64 was adjusted to be about twice as long as the track pitch in order to keep the recorded magnetic domain width narrower than the track pitch. In addition, in the test recording area, in addition to the isolated magnetic domains 64, a magnetic domain array 65 (hereinafter, referred to as a continuous magnetic domain 65) obtained by emitting a laser with a recording clock was formed.

Test recording was performed on the isolated magnetic domains 64 and the continuous magnetic domains 65 by changing the recording light power in the lands of some test signal recording tracks different from the above-mentioned areas. FIG. 4 shows reproduction signals from the isolated magnetic domain 64 and the continuous magnetic domain 65 recorded with various recording light powers. In FIG. 4, the appropriate power is a power at which Δ1 described later becomes Δ1 = 0, and a larger laser power and a smaller laser power are defined as overpower and underpower, respectively. In the reproduced signal from the continuous magnetic domain 65, since the magnetic domains overlap each other, even if the laser power is low, the waveform of the reproduced signal from each magnetic domain also overlaps, and even if the laser power is changed, the amplitude of each signal changes substantially. do not do.

On the other hand, in the isolated magnetic domain 64, the average value of the signal levels shown by the horizontal broken line in FIG. 4 greatly fluctuates because the degree of overlap of the signal waveforms from the adjacent magnetic domains changes depending on the laser power. Here, the difference Δ1 between the average value of the reproduction signal level of the isolated magnetic domain 64 and the average value of the reproduction signal level from the continuous magnetic domain 65 greatly changes with the change of the recording light power. As shown in FIG. 5, the change in Δ1 with respect to the laser power is larger than the signal in the continuous magnetic domain 65, that is, the change Δ2 in signal level when recording is performed with all recording clocks. Therefore, rather than adjusting the laser power and the like based on the reproduction signal level obtained from the magnetic domain (continuous magnetic domain) recorded by the ordinary optical magnetic field modulation recording method, and controlling the magnetic domain width based on the above Δ1, It is possible to control the magnetic domain width more precisely by adjusting the parameters. Δ1 (p) at each laser power obtained as described above is stored in a control system (not shown) in association with the laser power.

Here, an example of a detection system for detecting the above Δ1 (p) is shown in the block diagram of FIG. A test recording signal reproduced from the isolated magnetic domain 64 and the continuous magnetic domain 65 recorded under various laser powers is passed through a low-pass filter having a cut-off frequency lower than the signal frequency, and the peak value and the bottom value are sampled and held. The difference between the signal levels of the isolated magnetic domain 64 and the continuous magnetic domain 65 is obtained by obtaining the value and calculating the difference from the subtractor. After A / D conversion of the difference (amplitude Δ1 (p)) between the peak value and the bottom value at each laser power, the Δ1 (p) value is compared with a reference value (reference signal amplitude) Δ0 to obtain a reference value. A value Δ1 (p) closest to the value Δ0 is searched to obtain a laser power p corresponding thereto. Here, the reference value Δ0 is an ideal Δ1 value corresponding to a target magnetic domain width in the land portion, and is a constant value determined in advance in a design stage in consideration of crosstalk, track pitch, and the like. The reference value Δ0 is set to Δ0 = 0 because the signal amplitude change due to the variation of the Kerr rotation angle of the magneto-optical recording medium is hardly affected by the DC offset or the like of the circuit.

(4) The obtained laser light power p becomes a laser power for obtaining a predetermined magnetic domain width corresponding to the reference value Δ0 = 0 when a test pattern is recorded on the land.

Next, in the groove portion, the magnetic domain of the test pattern is trial-written with various laser powers in the same manner as described above, and the laser power p is determined so that Δ1 (p) becomes the reference value Δ0 = 0. Thus, the laser power p determined independently for the land portion and the groove portion is represented by PL (0) and PG (0), respectively. Since these laser powers PL (0) and PG (0) are independently determined powers in the land portion and the groove portion, are the optimum powers in a range where cross-writing does not occur in adjacent tracks, respectively? I don't know. Therefore, in the following steps, PL (0) and PG (0) are used as initial values, and the power for recording on the groove portion and the power for recording on the land portion are referred to a reproduction signal from an adjacent track. Adjust with.

The test signal recording track may be a part 41 outside the user area 42 on the innermost or outermost disk as shown in FIG. 7 or a ZCAV format as shown in FIG. It may be a part 41 of the non-user track near the zone boundary not used by the user.

[Second step: setting of recording light power PG (i) in groove portion]
First, a land portion for recording a test signal with the initial power value PL (0) determined in the first step and a groove portion adjacent on both sides of the land portion are respectively provided with a recording light power larger than PL (0) and PG (0). Initialization is performed so that the magnetization directions of the magnetic domains are aligned in one direction. Then, as shown in FIG. 9, a single repetition pattern 96 is recorded with the laser power PL (0) on the central land portion 90, and then the groove portions 92 and 94 adjacent on both sides are initialized at intervals of about 10 bytes. The continuous patterns 98 and 99 are recorded in the same direction as the magnetization direction. When recording the groove portions 92 and 94, the recording light power is increased or decreased around PG (0). For example, the power is sequentially changed such as PG (0) -2.0 mW, PG (0) -1.0 mW, PG (0), PG (0) +0.1 mW, PG (0) +0.2 mW for each sector. While recording, the same patterns 98 and 99 are recorded. FIG. 9 shows the case where the groove portion was recorded with the power of PG (0) +0.2 mW (b), FIG. 10 shows the case where the groove portion was recorded with the power of PG (0), and FIG. This shows a case where a groove portion is recorded with a power of PG (0) -0.2 mW (b).

(4) After recording the groove portions 92 and 94 on both sides with various powers as described above, the test pattern 96 on the central land portion 90 is reproduced. The waveforms of the reproduced signals are shown below the magnetic domain patterns in FIGS. In FIG. 9, since it is considered that the patterns 98 and 99 are recorded in the groove portions 92 and 94 due to the overpower, the amplitude of the reproduction signal from the magnetic domain 80 of the land portion sandwiched between the patterns 98 and 99 is influenced by the cross write. Therefore, the amplitude of the reproduced signal from the magnetic domain 82 in the land portion where the patterns 98 and 99 are not recorded in the groove portions 92 and 94 is smaller. In FIG. 10, since it is considered that the patterns 98 and 99 are recorded in the groove portions 92 and 94 with appropriate power, the amplitude of the reproduction signal from the magnetic domain 80 of the land portion sandwiched between the patterns 98 and 99 is Are substantially equal to the amplitude of the reproduction signal from the magnetic domain 82 in the land portion not interposed between the two. In FIG. 11, since it is considered that the patterns 98 and 99 are recorded in the groove portions 92 and 94 with the under power, the amplitude of the reproduction signal from the magnetic domain 80 of the land portion sandwiched between the patterns 98 and 99 is Are not affected by the patterns 98 and 99, and the amplitude of the reproduced signal is equal between the magnetic domain 80 and the magnetic domain 82. Accordingly, the amplitude of the reproduced signal from the magnetic domain 82 of the land portion where the adjacent groove portion is not recorded is subtracted from the amplitude of the reproduced signal from the magnetic domain 80 of the land portion where the adjacent groove portion is recorded. Of the recording light power PG is the proper power (recording light power in the case of FIG. 10).

FIG. 12A shows the relationship between the ratio (relative amplitude) of the reproduction signal from the magnetic domain 80 and the magnetic domain 82 of the land recorded with the power of PL (0) and the power of the recording light recorded on the adjacent groove. . As shown in FIG. 12A, when the recording light power to the groove portion exceeds the appropriate power, the ratio (relative amplitude) of the reproduction signal from the magnetic domain 80 and the magnetic domain 82 in the land portion decreases.

適 正 Let PG (1) be the appropriate power for recording the groove portion determined in the second step.

[Circuit for Determining Recording Light Power PG (i)]
Here, a circuit for determining the recording light power PG (i) in the second step will be described. FIG. 13 is an example of a circuit for determining the recording light power PG (i). In FIG. 13, a peak value and a bottom value of a test waveform are obtained by a peak hold circuit and a bottom hold circuit (negative peak hold circuit), and a difference between outputs of the two circuits is obtained by a difference detection circuit. The difference detection circuit also has a low-pass filter function. After the obtained difference signal is sampled and held by a sample and hold circuit (S / H circuit), it is subjected to A / D conversion, and the difference between a portion where recording has been performed on an adjacent groove portion and a portion where recording has not been performed has been performed. The signal levels are compared by a comparator. The recording light power to be recorded in the land (or groove) in the recording light power setting circuit is set based on the comparison result of the comparator. A memory is connected to the recording light power setting circuit, and the set recording light power value is temporarily stored in the memory, and is used as PG (0) (or PL (0)) at the next recording. be able to.

FIG. 14 shows the waveforms of the sample hold pulse and the timing pulses 1 and 2 supplied to the sample hold circuit shown in FIG. 13 together with the magnetic domain pattern of the land portion and the waveform of the reproduction signal shown in FIG. FIG. 14 also shows the output waveform from the difference detection circuit.

FIG. 15 shows an example in which a peak hold and a bottom hold are executed using two sample hold circuits (S / H circuits) as a modified example of the circuit shown in FIG. FIG. 16 shows waveforms of the sample hold pulse 1 and the sample hold pulse 2 input to the two sample hold circuits shown in FIG. 15, and the timing pulse 1 and the timing pulse 2 input to the level comparator. The circuit shown in FIG. 15 can determine PG (i) (or PL (i)) with higher accuracy because the signal is sampled at more points than the circuit shown in FIG.

FIG. 17 shows another modification of the circuit shown in FIG. The block diagram shown in FIG. 17 shows that the reproduced waveform of the test signal is sampled and held by the sample and hold circuit (S / H circuit) at the timing of the PLL clock, and is further subjected to A / D conversion and digitized amplitude in each magnetic domain. Get data. The amplitude data of the magnetic domain in the initialization direction (white) at the land portion recorded on the adjacent groove portion is D0, and the amplitude data of the magnetic domain (80 in FIG. 9) in the recording direction (black) is D1. . The amplitude data of the data of the magnetic domain in the initialization direction (white) in the portion where recording is not performed in the adjacent groove portion is D2, and the amplitude data of the magnetic domain (82 in FIG. 9) in the recording direction (black) is D3. . These data D3, D2, D1, and D0 are stored in four memories in the MPU, respectively, and the arithmetic processing unit performs an operation of (ΣD3-ΣD2)-(ΣD1-ΣD0) = ΔD to obtain an adjacent groove unit. The difference .DELTA.D between the amplitude at the place where recording is performed and the location at which recording is not performed is determined. As shown in FIG. 17, when ΔD is not equal to or smaller than the predetermined value a, the recording light power setting circuit sets the recording light power again to perform recording and reproduction, and then performs the above calculation again. Then, the above calculation is repeated while changing the recording light power until ΔD becomes equal to or less than the predetermined value a, whereby the proper recording light power for the groove portion can be set.

Also, using the circuit shown in FIG. 17, the S / N decreases and the jitter increases in a place affected by the cross write from the adjacent groove portion. Therefore, the standard deviation of D0 to D3 is calculated in the MPU. You may compare it. Alternatively, the comparison may be made based on a difference between error rates instead of a difference between signal amplitudes.

[Third Step: Setting of Recording Light Power PL (i) of Land]
The appropriate power for land recording is adjusted using the appropriate power PG (1) for groove recording determined in the second step.

操作 In this step, the same operation as that in the second step is performed on three tracks whose central groove is sandwiched between lands. First, the groove portion and the land portions adjacent to the groove portion are initialized with recording light power larger than PG (1) and PL (0), respectively, so that the magnetization directions are aligned in one direction. Then, a single repetitive pattern is recorded in the central groove portion with the recording light power of PG (1). Thereafter, recording is performed on the land portions adjacent on both sides in the same direction as the magnetization direction initialized at intervals of about 10 bytes (see FIG. 9). At this time, the power of the recording light to be recorded on the land is increased or decreased around PL (0). For example, the power is sequentially changed such as PG (0) -2.0 mW, PG (0) -1.0 mW, PG (0), PG (0) +0.1 mW, PG (0) +0.2 mW for each sector. While recording the same test pattern.

(4) Thereafter, the central groove portion is reproduced, and the amplitude of a place where recording is performed on an adjacent land portion is compared with the amplitude of a place where recording is not performed, to determine an appropriate power PL (1). The appropriate power PL (1) is determined in the same manner as the determination of the appropriate power PG (1) in the same manner as the magnetic domain of the groove recorded on the adjacent land and the groove not recorded on the adjacent land. The maximum power at which the difference between the amplitudes of the reproduced signals from the magnetic domains becomes zero is set. FIG. 12B shows the ratio (relative) of the reproduction signal from the magnetic domain of the groove portion recorded on the adjacent land portion recorded with the power of PG (1) to the magnetic domain of the groove portion not recorded on the adjacent land portion. (Amplitude) and the power of the recording light recorded on the adjacent land. As shown in FIG. 12B, when the power of the recording light to the groove exceeds the proper power, the ratio (relative amplitude) of the reproduction signal from the groove decreases. The method for detecting the appropriate power is the same as that in the second step, and the circuit shown in FIG. 13, FIG. 15, or FIG. 17 can be used.

(4) Whether the proper recording light power PL (1) for the land determined in this way is optimal can be checked by calculating the difference between PL (1) and PL (0). That is, when the difference between PL (1) and PL (0) is sufficiently small, for example, when | PL (0) −PL (1) | <1 mW, PG (1) and PL ( A series of test writing operations is completed with 1) as the optimum recording light power.

If the difference between PL (1) and PL (0) is larger than a predetermined value, the second step is performed again using PL (1) to determine PG (2), and PG (2) is determined. To determine the appropriate recording light power PL in the third step.

[Example of operation procedure]
An example of an operation procedure for determining the optimum recording light power for recording on the land portion and the groove portion is shown in the flowchart of FIG. This flowchart starts when recording is performed on a land-groove type magneto-optical recording medium or when the power of the recording / reproducing apparatus is turned on (step 200). PL (0) and PG (0) are determined according to the above-described first step (steps 202 and 204). Next, an appropriate power PG (i) (i = 1) is determined using PL (0) according to the second step (step 206). Then, whether or not PG (i) is the optimum power is determined by whether or not | PG (i) −PG (i−1) | <ΔG (ΔG is a preset value, for example, 1 mW). Check (step 208). If not satisfied or satisfied but i = 1 (step 224), the process proceeds to step 210, where i> N is determined (where N is the maximum value of the number of repetitions, usually 3 or 4). If i> N, the process ends abnormally (step 230).

If i ≦ N, the proper power PL (i) of the land is determined using PG (i) in step 212 according to the method described in the third step. Next, whether or not the appropriate power PL (i) is optimal is determined by whether or not | PL (i) −PL (i−1) | <ΔL (ΔL is a preset value, for example, 1 mW). Check (step 214). If it is satisfied and PG (i) is optimal, the process ends normally because both PL (i) and PG (i) have optimal power (step 232). | PL (i) −PL (i−1) | <ΔL is satisfied, but PG (i) determined in step 206 is not optimal, and | PL (i) −PL (i−1) | <ΔL Is not satisfied, the process proceeds to step 216, where i> N is determined.

If i ≦ N in step 216, i = i + 1 (step 218), then return to step 206, determine PG (i) again, and continue the operation from step 208. If the condition is satisfied in step 208 and | PL (i-1) -PL (i-2) | <[Delta] L is satisfied, the process ends normally because both optimum powers PL and PG have been determined (step 208). 234). If i> N in step 216, the process ends abnormally (step 230).

The operation procedure shown in FIG. 18 is merely an example, and the optimum power of the land and the groove can be determined by various procedures. For example, in the operation of the first step (steps 202 and 204), values set in advance as PL (0) and PG (0) may be used. This set value can be stored in a memory or the like of the recording / reproducing device (drive). Further, once the optimum recording light powers PL (i) and PG (i) are determined according to the above-mentioned flowchart, the optimum recording light powers PL (i) and PG (i) when the next recording is performed under certain conditions. PG (i) can be used as the value of PL (0) and PG (0). The values of the optimum recording light powers PL (i) and PG (i) can be stored in, for example, a memory connected to the recording light power setting circuit shown in FIGS.

In the above embodiment, the test pattern is recorded on the land with the power PL (0), the power to be recorded on the groove on both sides is changed to determine the appropriate recording light power of the groove, and the power is written on the groove. The operation of recording the test pattern with PG (0) and changing the power to be recorded on the land portions on both sides of the test pattern to determine the appropriate recording light power of the land portion were continuously performed, but only one of the operations was performed. May be performed. Either operation alone is effective for preventing cross light.

It is preferable that the method for determining the optimum recording light power by the test writing described in the above embodiment is executed at the time of starting the operation of the recording / reproducing apparatus equipped with the land-groove type magneto-optical recording medium. Alternatively, the above method may be executed at an interval of 1 minute to 10 minutes from the time when the magneto-optical recording medium is mounted on the recording / reproducing apparatus or the time when the magneto-optical recording medium is mounted on the recording / reproducing apparatus. Furthermore, when recording is performed for a long time in order from the inner circumference or the outer circumference of the medium, it may be performed before the start of recording. When recording is performed for a long time in order from the inner circumference or the outer circumference in the ZCLV, the printing can be performed every time at the zone boundary or every several zones.

Although the optimum power of the recording light of the land-groove type magneto-optical recording medium is determined in the first embodiment, a method of simultaneously determining the optimum power of not only the recording light but also the reproducing light by trial writing will be described.

(4) A test pattern is recorded / reproduced on the land-groove type optical recording medium shown in FIG. 2 according to the following first to fourth steps. Here, one circumference (one track) of the land-groove type optical recording medium is divided into B blocks. Assuming that the number of sectors is L, each block includes B / L sectors.

[First Step: Recording of Test Pattern A]
After the optical head is positioned on the n-th track (land area) of the area for recording the test signal, the test is performed while sequentially increasing the recording light power every time the block changes from the 0th block (0th sector) to the Bth block. Record pattern A. For example, the 0th block is recorded with power P0, the first block is recorded with power P0 + Δ, the second block is recorded with power P0 + 2Δ,..., The mth block is recorded with power P0 + mΔ. Recording is performed in each sector included in the block of the same number with the laser beam of the same power. The recording light power Pw of the m-th block of the n-th track is represented by Pw (n, m) = P0 + mΔ.

[Second Step: Recording of Test Pattern B]
Next, in the groove portions adjacent to both sides of the land portion (n-th track) on which the test pattern A is recorded as described above, that is, in the (n + 1) th track and the (n-1) th track, recording is performed on each block of the land portion. The test pattern B is recorded with the same power as that performed. The recording light power Pw (n + 1, m) = Pw (n-1, m) = P0 + mΔ for the (n + 1) th track and the (n−1) th track. In this example, B = 5, L = 20, P0 = 5 mW, and Δ = 1 mW.

[Third Step: Reproduction of Test Pattern A]
After recording the test pattern B in the groove portions on both sides as described above, the pattern A recorded in each block of the n-th track is reproduced. The n-th track was reproduced while changing the power Pr of the reproduction light to various intensities, in this example, Pr = 1.0 mW, 1.5 mW, 2.0 mW, 2.5 mW, and 3.0 mW.

[Fourth step: determination of optimum recording / reproducing light power]
The number of errors was measured from the reproduced signal, and the number of sectors S (Pr) in which the number of errors in the sector in each block did not exceed the reference value was obtained. This operation is performed for each reproduction light power Pr, and S (Pr) at various recording light powers and various reproduction light powers is shown in the table of FIG. At the right end of the table, the total S of S (Pr) from all blocks at each reproduction light power is displayed. Pr having the largest S can be set as the optimum reproduction light power Prbest, and it can be seen from the table that Prbest = 2.0 mW. Further, the optimum recording light power Pwbest can be set to the recording light power that gives the largest S (Pr) in S (Pr) in Prbest. In the table, when Pr = 2.0 mW, S (Pr) = 4 at Pw = 6 mW, 7 mW, and 8 mW, so that Pw = 7 mW as the central power was set as the optimum recording light power Pwbest. Thus, the optimum reproduction light power Prbest = 2.0 mW and the optimum recording light power Pwbest = 7 mW were obtained.

In the first step, first, after recording each block of the n-th track in the pattern A with the same recording light power, error measurement of each sector may be performed, and defective sectors may be excluded in advance. By doing so, it is possible to eliminate an error of the reproduction signal based on an initial defect such as a defect from an error of the reproduction signal by the cross write, and it is possible to more accurately determine the optimum recording and reproduction light power.

In the fourth step, the total S of S (Pr) is obtained from all the blocks at each reproducing light power, and Pr having the maximum S is determined as the optimum reproducing light power. The total S ′ of S (Pr) from the reproduced signal is obtained, and the recording light power that becomes the maximum S ′ can be set as the optimum recording light power Pwbest. In the table of FIG. 20, the optimum recording light power Pwbest is 7 mW. Then, the optimum reproduction light power Prbest can be set to a power at which S (Pr) in the optimum recording light power Pwbest becomes maximum, that is, 2.0 mW or 2.5 mW. By selecting the optimum recording light power and the optimum reproduction light power in this way, the recording light power margin can be set to the maximum.

In the above embodiment, the test pattern A is recorded on the land portion (n-th track), and the test pattern B is recorded on the groove portions (n + 1 and n-1 tracks) on both sides thereof. The optimum recording and reproducing light power for the land portion was defined as the optimum recording light power and optimum reproducing light power of the land-groove type optical recording medium. However, the test pattern A is recorded on the groove portion (for example, the (n + 1) th track), and the test pattern B is recorded on the land portions (for example, the nth and (n + 2) th tracks) on both sides thereof. The optimum power for recording and reproducing in the groove portion can be determined by detecting the reproduction signal from the groove portion according to the above. That is, it is possible to determine the optimum recording and reproducing light powers for the land and the groove, respectively, and to cope with the difference in the focus between the recording and the reproducing light on the land and the groove.

The operations in the first to fourth steps are repeatedly performed at a predetermined timing such as when the drive is started. If the operations of the first to fourth steps are performed at a certain timing and then the operations of the first to fourth steps are performed again at the next timing, it is preferable to sequentially reduce the recording light power in the first step. For example, the recording light power Pw (n, m) = P0 + mΔ of the n-th block determined in the first step can be set to Pw (n, m) = P0 + (L−m) Δ. In this way, by changing the order of the recording light power every time test writing is performed, the maximum recording light power portion is distributed to two blocks in the same track, so that the deterioration of the test writing area is reduced.

Modification of Second Embodiment FIG. 27 shows a modification of the second embodiment. In the second step of the second embodiment, the test pattern B is recorded with the same recording light power in the groove portions adjacent to both sides of the land portion where the test pattern A is recorded. Examples in which test patterns are recorded with different recording light powers will be described. FIG. 27 is a sector arrangement diagram of a region where a test pattern of a land-groove type optical recording medium is recorded (test writing is performed), and sectors N, N + 1, N + 2... N + Q are arranged in the horizontal direction of the drawing. It is assumed that tracks m, m + 1, m + 2... M + R are arranged in the vertical direction. Test patterns are recorded in sectors of each track with different recording light powers.

The recording light power is changed at a constant rate such that Wr10 <Wr11 <Wr12 <Wr13... <Wr1Q, Wr1Q <Wr10, Wr10 <Wr20 <Wr30 <Wr40. And the track number. For example, the change rate of the recording light power for each sector can be α, and the change rate of the recording light power for each track can be β (α <β). That is, since all the sectors are recorded with different recording light powers, for example, the Nth sector of the (m + 1) th track (for example, a land portion) and the mth track (in this case, the groove) The Nth sector of the (m) section and the Nth sector of the (m + 2) th track (in this case, the groove section) are recorded with different recording light powers. In this case, a cross write occurs depending on the relationship between the recording light powers between adjacent sectors. Then, similarly to the second embodiment, the reproduction light power is modulated into various values for each sector and reproduced.

変 調 When the reproducing light power is modulated into various values for each sector, the reproducing light power can be changed every time the entire area is reproduced. Then, as shown in FIG. 20, a matrix condition indicating the relationship between the recording light power and the reproduction light power is created. The optimum recording light power and the optimum reproduction light power can be determined by the method described above. The optimum recording light power can be obtained by taking the average of the recording light powers of the sectors on both sides of the sector having the lowest error rate. In this modification, the test area can be reduced and the test time can be reduced as compared with the second embodiment. Further, the optimum recording light power can be determined independently for the groove portion and the land portion.

In the second embodiment and the modification, the case where magneto-optical recording is performed on the land-groove type optical recording medium shown in FIG. 2 has been described. However, the present invention is effective for a magneto-optical recording medium capable of reproducing by magnetic super-resolution. It is. The magnetic super-resolution reproducing method can dramatically increase the optical resolution by utilizing the temperature characteristics of the mask layer. That is, even a minute magnetic domain having a size smaller than 1/2 of the spot diameter of the reproduction light can be reproduced independently. However, the mask shape of the mask layer for masking other minute magnetic domains from the reproduction light also changes depending on the intensity of the reproduction light. Therefore, if the reproduction light intensity is not appropriate, high resolution by the magnetic super-resolution reproduction method cannot be obtained, and the S / N of the reproduction signal may be reduced. Then, the method of this embodiment is applied to a magneto-optical recording medium capable of reproducing by magnetic super-resolution, and the optimum power intensity of the reproducing light of magnetic super-resolution is obtained using a table as shown in FIG. be able to. As a result, a high-resolution and high-S / N reproduction signal can be obtained from the land-groove type magneto-optical recording medium of the magnetic super-resolution reproduction system.

In the first and second embodiments, test writing of a test pattern was performed to determine the optimum recording power and the optimum reproduction power. In the present embodiment, a recording / reproducing method for a magneto-optical recording medium capable of preventing deterioration due to excessive use of a test writing area will be described.

方法 The method of the present invention will be described with reference to FIG. FIG. 21 is a diagram conceptually showing a part of the arrangement in the n-th track of the optical recording medium as shown in FIG. In the figure, a plurality of test writing areas exist in the n-th track, and a data area is arranged behind each test writing area. In the present invention, auxiliary information for selecting one test writing area from a plurality of test writing areas is recorded in an area different from the test writing area. Also, it is designed so that ordinary users cannot record user data in the address of the auxiliary information.

In FIG. 21, a test writing area A, a data area A, a test writing area B, and a data area B are arranged behind the auxiliary information. Hereinafter, for the sake of simplicity, it is assumed that there are only the test writing area A and the test writing area B as the plurality of test writing areas, and examples of the two types of auxiliary information shown in FIGS. It will be described while using.

In FIG. 22A, the auxiliary information includes the number of times test writing is performed using each test writing area and information that can determine whether test writing to each test writing area is permitted or not. You. That is, the auxiliary information shown in FIG. 22A can determine whether CNT_A indicates the number of times test writing has been performed using the test writing area A and whether test writing to the test writing area A is permitted. The information FLG_A includes information FLG_A, CNT_B indicating the number of times of trial writing performed using the trial writing area B, and information FLG_B that can determine whether trial writing to the trial writing area B is permitted or not.

In FLG_A, “1” is recorded when trial writing to the trial writing area A is permitted, and “0” is recorded when trial writing to the trial writing area A is not permitted. Similarly, “1” is recorded in FLG_B when test writing to the test writing area B is permitted, and “0” is recorded when test writing to the test writing area B is not permitted.

A procedure for selecting one test writing area from the two test writing areas A and B using the auxiliary information shown in FIG. 22A will be described with reference to FIGS. 23 and 25. FIG. 23 is a flowchart showing an example of a procedure for selecting one test writing area from the test writing area A and the test writing area B from the auxiliary information shown in FIG. FIG. 25 shows the relationship between the contents of the auxiliary information and the test writing area used.

When the number of times of trial writing using the trial writing area A in which the trial writing is permitted is equal to or more than the preset number, the further writing to the trial writing area A is not permitted. The auxiliary information is rewritten. Here, when CNT_A reaches hexadecimal FFFF, FLG_A is changed from “1” to “0”. In addition, when the number of times of trial writing using the trial writing area where the trial writing is permitted is larger than the preset number, another trial writing area where the trial writing has not been performed in the past is set as The auxiliary information is rewritten so that test writing can be permitted as a new test writing area. Here, when CNT_A reaches hexadecimal FFFF, FLG_B is changed from “0” to “1”. Next, as in the case of the area A, the test writing is performed until the number of times of the test writing reaches the upper limit in the test writing area B. When the number of times of test writing in the area B reaches the upper limit, FLG_B is rewritten to “0” again, and test writing is performed in the next test writing area (C).

As described above, since the upper limit of the number of times of trial writing is set in each trial writing area, the trial writing is repeated many times, and before the recording medium is thermally damaged and the recording characteristics are changed, another trial writing is performed. Can be used. Therefore, test writing using a test writing area having stable recording characteristics becomes possible, and recording conditions can be optimized.

On the other hand, in FIG. 22 (b), it is composed of the number of times CNT in which the test writing is executed using the test writing area where the test writing is allowed, and information DST for specifying the test writing area where the test writing is allowed.

A procedure for selecting one test writing area from the test writing area A and the test writing area B using the auxiliary information shown in FIG. 22B will be described with reference to FIGS. FIG. 24 shows a flowchart of a procedure for selecting one test writing area from the test writing area A and the test writing area B from the auxiliary information shown in FIG. FIG. 26 shows the relationship between the contents of the auxiliary information and the test writing area used.

In FIG. 26, when DST is "1", test writing area A is used, and when DST is "2", test writing is performed using test writing area B. If the number CNT of test writing performed using a test writing area in which test writing is permitted is larger than a preset number, another test writing area in which test writing has not been performed in the past is replaced with a new test writing area. The auxiliary information is rewritten so that test writing can be permitted as a test writing area. Here, when CNT reaches hexadecimal FFFF, DST is changed from “1” to “2”, and the used test writing area is changed from test writing area A to test writing area B. Is equivalent. As described above, since the upper limit of the number of times of trial writing is set in each trial writing area, it is possible to prevent the recording medium from being thermally damaged due to repeated trial writing many times and the recording characteristics from being changed. The stable trial writing becomes possible as in the case of FIG.

In the description of FIG. 21, it is assumed that there are a plurality of test writing areas on the same track, but it is also possible to have a plurality of test writing areas on the same sector, which is included in the scope of the present invention. .

In the first to third embodiments, a test reading area may be provided in the vicinity of the test writing area or in a part of the test writing area. In the test reading area, a recording magnetic domain having a changed recording frequency or the like is recorded at the time of shipment. The trial reading area is an area where a normal user cannot erase or record. Using the reproduction condition setting signal recorded in the test reading area, the jitter can be measured based on the clock mark, and the amplitude of the reproduction signal can be evaluated. Further, the bit error rate may be measured. Using the results of these trial readings, it is possible to optimally adjust the output timing and intensity of the external magnetic field, if necessary, such as the output and irradiation timing of the reproduction laser, and reproduce the user data under such optimum conditions. Become. The reproduction condition setting signal to the test reading area can be transmitted by the manufacturer before shipment. In magnetic super-resolution and land / groove recording, it is desirable that the playback conditions be optimized. For these applications, it is not possible to record information including the playback conditions on the medium in advance and read it out on a trial basis. Especially effective.

Although the embodiment of the present invention has been described by taking as an example a case where recording is performed by a magneto-optical field modulation method using a land-groove type magneto-optical recording medium, an optical modulation method or a magnetic field modulation method may be used. Further, the optical recording medium is not limited to the land-groove type magneto-optical recording medium shown in FIG. 2, but may be used for recording various rewritable land-groove type optical recording media such as a land-groove type phase-change optical recording medium. The present invention can be applied to reproduction and reproduction.

According to the method of determining the optimum recording light power of a land-groove type optical recording medium of the present invention, cross-write or cross-erase occurs when recording is performed on a land or a groove adjacent to both sides of the groove. In addition, it is possible to select a recording light power capable of maximizing the S / N.

According to the method for determining the optimum recording light power and the optimum reproduction power of a land-groove type optical recording medium of the present invention, the recording light power is modulated into various values when recording the groove portions on both sides of the land portion. In addition, the reproduction light power for reproducing the land portion is also modulated to various powers, and the error rate is minimized from among a plurality of reproduction signals obtained by various combinations of recording light power and reproduction light power. The combination of the optimum recording light power and the optimum reproduction light power can be determined. In this method, not only the recording light power but also the reproduction light power can be optimized at the same time. Therefore, a magneto-optical recording medium using a magnetic super-resolution reproduction method in which the resolution and S / N change significantly depending on the reproduction light power. It is very suitable for

Further, in the present invention, auxiliary information for selecting one test pattern recording area from the plurality of test pattern recording areas is stored in an area of the optical recording medium different from the test pattern area. Deterioration due to excessive use can be prevented. The recording / reproducing device of the present invention is a device suitable for executing the method for determining the optimum recording light amount and the method for determining the optimum recording and light amount of the present invention, and performs the recording and reproduction of information with the determined optimum light amount. In addition, there is no cross write between lands and grooves of a land-groove type optical recording medium, and high S / N reproduction can be realized.

FIG. 1 is a diagram showing an overall configuration of a recording / reproducing apparatus for a land-groove type magneto-optical recording medium used in an embodiment of the present invention. FIG. 1 is a schematic diagram showing a structure of a land-groove type magneto-optical disk used in an example of the present invention. FIG. 5 is a diagram for explaining a method of determining PL (0) in the first step of the first embodiment, and is a timing chart showing a relationship among a recording laser pulse, a recording external magnetic field, a recording magnetic domain, and a signal reproduced therefrom in the magneto-optical recording method. It is. FIG. 4 is a diagram showing a relationship between a read signal from a recording magnetic domain recorded in a first step of Example 1 and a recording laser power. 4 is a graph showing a relationship between laser recording power and Δ1 and Δ2 in a reproduction signal from a recording magnetic domain recorded by a magneto-optical recording method in the first step of Example 1. FIG. 4 is a block diagram of a detection system for obtaining Δ1 in the embodiment. FIG. 1 is a plan view of a land-groove type magneto-optical disk showing a test recording area where a test signal is recorded by a magneto-optical recording method in an embodiment of the present invention. FIG. 1 is a plan view of a land-groove type magneto-optical disk showing a test recording area where a test signal is recorded by a magneto-optical recording method according to an embodiment of the present invention. FIG. 8 is a diagram illustrating a pattern of a recording magnetic domain and a reproduction signal waveform obtained from the land when recording is performed with overpower in a groove sandwiching the land in the second step of the first embodiment. FIG. 7 is a diagram showing a pattern of a recording magnetic domain and a reproduced signal waveform obtained from the land when recording is performed with appropriate power on a groove sandwiching the land in the second step of the first embodiment. FIG. 7 is a diagram illustrating a pattern of a recording magnetic domain and a reproduction signal waveform obtained from a land portion when recording is performed with an under power in a groove portion sandwiching a land portion in a second step of the first embodiment. FIG. 12A is a graph showing the relationship between the relative amplitude from the magnetic domain of the center track at the power of PL (0) and the recording power of recording the magnetic domain on an adjacent track, and FIG. FIG. 12B shows the result when the center track is a groove. FIG. 4 is a diagram illustrating a circuit for determining a recording power PG (i) used in the first embodiment. 14 is a timing chart showing a sample-hold pulse and a timing pulse used in the circuit of FIG. 13 and a signal waveform after subtraction showing an output from a difference detection circuit. FIG. 4 is a diagram illustrating another example of a circuit for determining the recording power PG (i) used in the first embodiment. 16 is a timing chart showing a sample hold pulse and a timing pulse input to the circuit of FIG. FIG. 4 is another circuit block diagram for determining the recording power PG (i) used in the first embodiment. 6 is a flowchart illustrating an example of a procedure for determining an optimum recording light power according to the first embodiment. FIG. 9 shows the block and sector divisions of the track of the land-groove type optical recording medium used in the second embodiment and the test patterns A / B recorded in each sector. FIG. 11 is a table showing various recording light powers used when recording a test pattern in each block and combinations of various reproduction light powers used when reproducing a test pattern recorded with each recording power in the second embodiment. FIG. 13 is a diagram conceptually showing a part of the n-th track of the optical recording medium used in the third embodiment. FIG. 22 is a conceptual diagram showing contents of auxiliary information stored in the n-th track shown in FIG. 21, showing contents of two types of auxiliary information ((a) and (b)). 23 is a flowchart illustrating an example of a procedure for selecting one test writing area from the test writing area A and the test writing area B using the auxiliary information illustrated in FIG. 23 is a flowchart showing an example of a procedure for selecting one test writing area from the test writing area A and the test writing area B using the auxiliary information shown in FIG. 23 is a table showing the relationship between the contents of the auxiliary information shown in FIG. 22 (a) and the test writing area used. 23 is a table showing the relationship between the contents of the auxiliary information shown in FIG. 22 (b) and the test writing area used. FIG. 14 is a diagram conceptually showing the arrangement of sectors of a land-groove type optical recording medium used in a modification of the second embodiment.

Explanation of reference numerals

21 Magneto-optical disk 22 Laser 25 Polarizing prism 28 Photodetector 29 Magnetic coil 31 Phase adjustment circuit 37 Embedded clock extraction circuit 38 Decoder 39 PLL circuit 41 Test area 42 User area 61 Tracking pit 62 Embedded lock pit 64 Isolated magnetic domain 65 Continuous magnetic domain 90, 112 Land 94, 114 Groove 110 Recording magnetic domain 322 Clock source 324 Test data timing generation circuit

Claims (14)

A method for determining an optimum recording and reproducing light amount of a land-groove type optical recording medium,
A first step of recording test patterns with different recording light amounts in a plurality of areas of a land portion or a groove portion,
A second step of recording test patterns with different recording light amounts in a plurality of regions of the groove or land adjacent to both sides of the plurality of regions of the land or groove;
A third step of reproducing the plurality of test patterns recorded in the first step with various reproduction light amounts,
The reproduction light amount from an area that provides the reproduction signal with the least error among the plurality of reproduction signals with various reproduction light amounts from the plurality of test patterns reproduced in the third step is determined as the optimum reproduction light amount, and the reproduction signal with the least error Determining the optimum recording and reproducing light amounts of the land-groove type optical recording medium, comprising: In the fourth step, errors of reproduction signals from test patterns recorded and reproduced in various combinations of the recording light amount and the reproduction light amount reproduced in the third step are obtained, and the errors are summed for each reproduction light amount. The optimum reproduction light amount is obtained by setting the reproduction light amount having the smallest error sum as the optimum reproduction light amount and the recording light amount for generating the reproduction signal having the least error among the reproduction signals reproduced at the optimum reproduction light amount as the optimum recording light amount. 2. The method for determining an optimum recording and reproducing light amount of a land-groove type optical recording medium according to claim 1, wherein the optimum recording light amount is determined. In the fourth step, errors of reproduction signals from test patterns recorded and reproduced with various combinations of recording light amounts and reproduction light amounts reproduced in the third step are obtained, and the errors are totaled for each recording light amount. In this case, the recording light amount with the smallest total error is the optimum recording light amount, and the reproduction light amount that generates the reproduction signal with the least error among the reproduction signals from the test patterns recorded at the optimum recording light amount is the optimum reproduction light amount. 2. The method according to claim 1, wherein the optimum recording light amount and the optimum reproduction light amount are determined by the following method. In the first step, the land portion or the groove portion of the n-th track is divided into B regions, and the recording light amount Pw (n, m) = P0 + mΔ to be recorded in the m-th region (0 ≦ m ≦ B) ( Here, P0 is the recording light amount recorded in the area of m = 0, and Δ is the rate of change of the recording light amount),
In the second step, the groove portion or land portion of the (n + 1) th and (n-1) th tracks is divided into B regions, and the recording light amount Pw to be recorded in the mth region (0 ≦ m ≦ B) of the (n + 1) th track , Pw (n + 1, m) = P0 + mΔ, and the recording light amount Pw to be recorded in the m-th area (0 ≦ m ≦ B) of the (n−1) th track is Pw (n−1, m) = P0 + mΔ. 3. The method for determining an optimum recording light and reproduction light amount of a land-groove type optical recording medium according to claim 1 or 2. In the first step, each area includes a plurality of sectors, the plurality of sectors in the same area are recorded with the same recording light amount, and in the fourth step, the total number of sectors in which the number of errors in the sector does not exceed the reference value 2. The land groove according to claim 1, wherein S (Pr) is obtained for each area, and the reproduction light quantity having the largest total S of S (Pr) of the areas reproduced with the same reproduction light quantity is determined as the optimum reproduction light quantity. To determine the optimum recording and reproducing light amount of a type optical recording medium. The optical recording medium has a plurality of areas for recording the test pattern, when recording a test pattern, auxiliary information for selecting a recording area of one test pattern from the recording area of the plurality of test patterns, 6. The method according to claim 1, wherein the data is stored in an area different from the test pattern area. 7. The optimum recording of a land-groove type optical recording medium according to claim 6, wherein the auxiliary information includes information that can determine whether or not recording in each test pattern recording area is permitted. And the method of determining the reproduction light amount. 8. The land-groove type optical recording according to claim 6, wherein the auxiliary information includes the number of times of recording using a test pattern recording area in which recording of a test pattern is permitted. A method for determining the optimum recording and reproducing light amounts of a medium. When the number of times the test pattern is recorded using the test pattern recording area where the recording of the test pattern is permitted is larger than a preset number, further writing to the test pattern recording area is permitted. 9. The method according to claim 8, wherein the auxiliary information is rewritten so as not to be performed. If the number of times a test pattern has been recorded using a test pattern recording area where the recording of the test pattern is permitted is greater than a preset number, another test pattern has not been recorded in the past. 10. The optimum recording and reproducing light amount of the land-groove type optical recording medium according to claim 9, wherein the auxiliary information is rewritten so that the recording of the test pattern is permitted as a new recording area of the test pattern. How to determine. 11. The method for determining the optimum recording and reproducing light quantity of a land-groove type optical recording medium according to claim 6, wherein a recording area of a plurality of test patterns is provided on the same track. 12. The method according to claim 6, wherein a plurality of test pattern recording areas are provided on the same sector. A recording / reproducing method for a land-groove type optical recording medium for recording and reproducing information with a recording light amount and a reproduction light amount determined by the method according to claim 1. 14. The recording / reproducing method for a land-groove type optical recording medium according to claim 13, wherein the optical recording medium is a magneto-optical recording medium reproduced by magnetic super-resolution.

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