JP3762922B2 - Optimal recording and reproducing light amount determining method for optical recording medium and recording / reproducing method - Google Patents

Description

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

  In the magneto-optical recording medium, a multilayer film composed of at least one 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 advance in the track direction by injection molding, and a land portion (convex portion) is defined between the grooves. The land portion includes a data recording area for recording information and a header area in which address signals and the like are recorded in the form of prepits. Since the groove functions as a guide groove for tracking the optical head, no information is recorded.

  As the amount of information processing has increased in recent years, optical recording media capable of high-density recording have been demanded. Grooves are formed as wide grooves, and so-called land-groove type in which information is written not only in land portions but also in grooves. A magneto-optical recording medium has been devised.

  In the case of a land / groove type magneto-optical recording medium, since the track pitch is as narrow as 0.5 to 0.8 μm and information is also recorded in the groove part, the recording light power is adjusted with high accuracy to each recording domain. It is necessary to form the land portion and the groove portion constituting the track with optimum sizes. When the recording power is overpower, the domain recorded in the groove part (or land part) is formed so as to protrude to the adjacent land part (or groove part), and the information recorded in the adjacent track is destroyed. (Cross light / cross erase). On the other hand, when the recording power is underpower, the S / N of the reproduction signal decreases because the domain becomes smaller than the track width. Further, since the land portion and the groove portion have different focus positions, the optimum recording light power is different, and it is desirable to adjust each independently.

  Incidentally, 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. For this reason, it is necessary to perform recording while feeding back the influence of the recording device temperature and the medium temperature to the recording conditions. In addition, variations in the recording apparatus due to differences in the light spot shape due to aberration of the optical head and defocusing, differences in the characteristics of the laser light source, or variations among recording medium lots greatly affect the recording conditions.

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

  As described above, even in a land / groove type magneto-optical recording medium in which magnetic domains need to be formed in optimum sizes in the land portion and the groove portion, trial writing is performed by some method to optimize the power of recording light and the like. It is desirable. In addition, in the area where test writing is performed, there is a part where recording is performed with a recording laser having a higher output than the normal user data area. The recording characteristics of the writing area will change. For this reason, the recording condition obtained from the trial writing may not reflect the optimum condition of the recording area where recording is actually performed.

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

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

  A third object of the present invention is to provide a method for determining the optimum recording light quantity for preventing cross-write during recording on a land-groove type optical recording medium and improving the S / N during reproduction. is there. The fourth object of the present invention is to provide a land / groove magneto-optical recording medium recording / reproducing method and recording / reproducing apparatus for recording / reproducing the land / groove magneto-optical recording medium with the optimum recording light quantity and reproducing light quantity, respectively. There is.

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

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

  In the above 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 also modulated to various amounts. Thus, a plurality of reproduction signals obtained by combining various recording light amounts and reproduction light amounts are obtained, and an optimum recording light amount and optimum reproduction light amount combination that minimizes the error rate is determined among the plurality of reproduction signals. . In this method, not only the recording light quantity but also the reproduction light quantity can be optimized at the same time. Therefore, the magneto-optical recording medium using the magnetic super-resolution reproduction system in which the resolution and S / N change remarkably with the amount of the reproduction light. It is very suitable for.

  In the fourth step, the error of the reproduction signal from the test pattern recorded and reproduced by the combination of various recording light amounts and reproduction light amounts reproduced in the third step is obtained, and the error is determined for every reproduction light amount. The reproduction light amount with the smallest total error over the recording light amount is set as the optimum reproduction light amount, and among the reproduction signals reproduced with the optimum reproduction light amount, the recording light amount for generating the reproduction signal with the least error is the optimum recording light amount. By doing so, the optimum reproduction light quantity and the optimum recording light quantity 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, an error of the reproduction signal from the test pattern recorded and reproduced with a combination of various recording light amounts and reproduction light amounts reproduced in the third step is obtained, and the error is determined for each recording light amount. The recording light amount with the smallest total error is set as the optimum recording light amount over all the reproduction light amounts, and the reproduction signal with the least error among the reproduction signals from the test pattern recorded with the optimum recording light amount is generated. By setting the reproduction light amount as the optimum reproduction light amount, the optimum recording light amount and the optimum reproduction light amount can be determined. By adopting 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 groove portion of the n-th track is divided into B regions, and the recording light amount Pw (n, m) for recording in the m-th region (0 ≦ m ≦ B). = P0 + mΔ (where P0 is the recording light quantity recorded in the area of m = 0, and Δ is the change rate of the recording light quantity), and in the second step, the groove of the n + 1th and n−1th tracks Or the land portion is divided into B areas, and the recording light quantity Pw to be recorded in the mth area (0 ≦ m ≦ B) of the (n + 1) th track is Pw (n + 1, m) = P0 + mΔ, The recording light quantity Pw recorded in the mth region (0 ≦ m ≦ B) is preferably Pw (n−1, m) = P0 + mΔ. Each area includes a plurality of sectors in the first step, and a plurality of sectors in the same area are recorded with the same recording light amount. In the fourth step, the number of sectors in which the number of errors does not exceed a reference value. It is preferable that the total reproduction amount S (Pr) is obtained for each region, and the reproduction light amount having the largest total S (Pr) S of the regions reproduced with the same reproduction light amount is set 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 the test pattern is recorded, 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. By doing so, deterioration due to excessive use of the same test pattern recording area is prevented.

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

  In 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 or changing the pulse length of one recording light pulse.

  In the present invention, there is provided a land / groove type optical recording medium recording / reproducing method for recording and reproducing information with the recording light quantity and the reproduction light quantity determined by the method of 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 in a method for determining the optimum recording light power and reproducing light power of a land groove type magneto-optical recording medium. This apparatus includes a laser control system for irradiating a land-groove magneto-optical disk 21 to be described later with light pulsed at a constant period synchronized with code data, and a magnetic field control for controlling the magnetic field applied to the magneto-optical disk 21. The system is mainly composed of a system, a signal detection system for detecting a signal from the magneto-optical disk 21, and a drive controller 320 for controlling these control systems. In the laser control system, the laser 22 is connected to a laser drive circuit 32, and the laser drive circuit 32 receives a clock signal described later from the PLL circuit 39 and controls the laser 22. 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 is magnetic. 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 on the side thereof. The detectors 28 and 281 are both connected to the subtracter 302 and the 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 subtracter 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. The test data timing generation circuit 324 generates a sample hold pulse and a timing pulse, which will be described later.

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

  At the time of data recording, the laser 22 is optically modulated at a constant frequency so as to synchronize with the data channel clock by the laser driving circuit 32, emits a continuous pulse light having a narrow width, and the data recording area of the rotating disk 21 is set. Heat locally at intervals. In addition, the data channel clock controls the encoder 30 of the magnetic field control system to generate a data signal that is an integral multiple of the reference clock period. The data signal is sent to the magnetic coil driving device 34 through 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 the heating portion of the data recording area.

  An example of the structure of the magneto-optical disk 21 is shown in FIG. The magneto-optical disk 21 is a land-groove type magneto-optical disk having a wide groove portion 114 and having magnetic domains 110 formed in both the land portion 112 and the groove portion 114. On the substrate 101, there is usually formed 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 (here, to simplify the description) 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 light having various recording light powers using the recording / reproducing apparatus (drive) shown in FIG. (Test writing) A method of determining the optimum recording laser power for each of the land portion and the groove portion by reproducing them will be described.

[First step: Temporary recording light power setting 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 used as a track (nth track) in the land portion where test pattern test writing is performed. The magnetic head including the magnetic coil 29 is positioned in the vicinity of the track. Next, a test signal is recorded by irradiating a laser beam while applying an external magnetic field to the disk 1 in accordance with the test signal recording external magnetic field and recording laser pulse shown in FIG.

  When a recording signal is actually recorded in the magneto-optical modulation recording system, as shown in the magnetic domain group 65 of FIG. 3, lasers are emitted at all recording clocks to form overlapping magnetic domain rows. In this embodiment, in order to record a test signal for determining the appropriate recording light power (trial writing), the laser emission cycle is adjusted so that the recording clock is thinned out, and a short magnetic domain isolated in the test signal recording track area is isolated. 64 (hereinafter referred to as isolated magnetic domains 64) are formed (the left side of the magnetic domain pattern in FIG. 3). The interval between the isolated magnetic domains 64 was adjusted to about twice the track pitch so that the recorded magnetic domain width was narrower than the track pitch and not too narrow. Further, in addition to the isolated magnetic domain 64, a magnetic domain row 65 (hereinafter referred to as a continuous magnetic domain 65) overlapped with each other obtained by emitting a laser with a recording clock was formed in the test recording area.

  The isolated magnetic domain 64 and the continuous magnetic domain 65 were subjected to test recording by changing the recording light power in a land area of several test signal recording tracks different from the above-described area. FIG. 4 shows reproduced signals from isolated magnetic domains 64 and continuous magnetic domains 65 recorded with various recording light powers. In FIG. 4, the appropriate power is a power at which Δ1, which will be described later, becomes Δ1 = 0, and a larger laser power and a smaller laser power are overpower and underpower, respectively. The reproduced signals from the continuous magnetic domain 65 are overlapped with each other. Therefore, even if the laser power is low, the waveform of the reproduced signal from each magnetic domain also overlaps, and the amplitude of each signal changes almost even if the laser power is changed. do not do.

  On the other hand, in the isolated magnetic domain 64, the degree of overlap of the signal waveforms from adjacent magnetic domains varies depending on the laser power, so that the average value of the signal level indicated by the horizontal broken line in FIG. 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 changes greatly with the change of the recording light power. As shown in FIG. 5, the change amount of Δ1 with respect to the laser power is larger than the change amount Δ2 of the signal of the continuous magnetic domain 65, that is, the signal level when recording is performed with all recording clocks. Therefore, the laser power is controlled based on the above Δ1 rather than adjusting the laser power etc. based on the reproduction signal level obtained from the magnetic domain (continuous magnetic domain) recorded by the ordinary magneto-optical modulation recording method. More accurate control is possible by controlling the magnetic domain width by adjusting the above. Δ1 (p) at each laser power obtained as described above is stored in a control system (not shown) in correspondence with the laser power.

  Here, an example of a detection system for detecting 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 a peak value and a bottom are obtained by a sample hold pulse. The difference between the average values of the signal levels of the isolated magnetic domain 64 and the continuous magnetic domain 65 is obtained by obtaining the value and obtaining the difference from the subtracter. The difference between the peak value and the bottom value (amplitude Δ1 (p)) at each laser power is A / D converted, and then the Δ1 (p) value is compared with the reference value (reference signal amplitude) Δ0 to obtain the reference A value of Δ1 (p) closest to the value Δ0 is searched to obtain a leather power p corresponding to it. Here, the reference value Δ0 is an ideal Δ1 value corresponding to the target magnetic domain width in the land portion, and is a constant value determined in advance in the design stage in consideration of crosstalk, track pitch, and the like. The reference value Δ0 is set to Δ0 = 0 because the change in signal amplitude due to the variation in the Kerr rotation angle of the magneto-optical recording medium is not easily affected by the DC offset of the circuit.

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

  Next, also in the groove portion, the test pattern magnetic domains are test-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 each of the land portion and the groove portion is represented as PL (0) and PG (0), respectively. Since these laser powers PL (0) and PG (0) are powers determined independently in the land part and the groove part, are the optimum powers within a range in which no cross write occurs in adjacent tracks? I do n’t know. Therefore, in the following steps, PL (0) and PG (0) are set as initial values, and the reproduction signal from the adjacent track is referred to for the power for recording in the groove portion and the power for recording in the land portion, respectively. Adjust by.

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

[Second Step: Setting of Recording Light Power PG (i) of Groove Part]
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 to both sides of the land portion with a recording light power larger than that of PL (0) and PG (0), respectively. Initialize and align the direction of magnetization of each magnetic domain in one direction. Then, as shown in FIG. 9, a single repetitive pattern 96 is recorded on the central land portion 90 with the laser power PL (0), and thereafter, the groove portions 92 and 94 adjacent to both sides are initialized every about 10 bytes. Continuous patterns 98 and 99 are recorded in the same direction as the magnetized magnetization. When the grooves 92 and 94 are recorded, the recording light power is increased or decreased around PG (0). For example, the power is sequentially changed to PG (0) -2.0 mW, PG (0) -1.0 mW, PG (0), PG (0) +0.1 mW, and PG (0) +0.2 mW for each sector. The same patterns 98 and 99 are recorded. 9 shows a case where the groove portion is recorded with a power of PG (0) +0.2 mW (b), FIG. 10 shows a case where the groove portion is recorded with a power of PG (0), and FIG. A case where the groove portion is recorded with a power of PG (0) −0.2 mW (b) is shown.

  After recording the groove portions 92 and 94 on both sides with various powers as described above, the test pattern 96 of the central land portion 90 is reproduced. Reproduced signal waveforms 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 overpower, the amplitude of the reproduction signal from the magnetic domain 80 in the land portion sandwiched between the patterns 98 and 99 is influenced by the cross light. Thus, the amplitude of the reproduction 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 in the land portion sandwiched between the patterns 98 and 99 is the patterns 98 and 99. The amplitude of the reproduction signal from the magnetic domain 82 in the land portion not sandwiched between the two is substantially equal. In FIG. 11, since it is considered that the patterns 98 and 99 are recorded in the groove portions 92 and 94 due to underpower, the amplitude of the reproduction signal from the magnetic domain 80 in the land portion sandwiched between the patterns 98 and 99 is shown on both sides. Thus, the amplitude of the reproduction signal is the same in the magnetic domain 80 and the magnetic domain 82. Accordingly, the amplitude of the reproduction signal from the magnetic domain 80 in the land portion where the adjacent groove portion is recorded is subtracted from the amplitude of the reproduction signal from the magnetic domain 82 in the land portion where the adjacent groove portion is not recorded. Is the appropriate power (recording light power in the case of FIG. 10).

  FIG. 12A shows the relationship between the ratio (relative amplitude) of the reproduction signals from the magnetic domains 80 and 82 in the land portion recorded with the power of PL (0) and the recording light power recorded in the adjacent groove portion. . 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 signals from the magnetic domains 80 and 82 in the land portion decreases.

  The appropriate power for recording the groove portion determined in the second step is PG (1).

[Circuit for Determining Recording Optical 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, the peak value and the bottom value of the test waveform are obtained by the peak hold circuit and the bottom hold circuit (negative peak hold circuit), and the difference between the outputs of the two circuits is obtained by the difference detection circuit. The difference detection circuit also has a low-pass filter function. The obtained difference signal is sampled and held by the sample and hold circuit (S / H circuit), and then A / D converted and recorded from the portion where the recording was performed on the adjacent groove portion and the portion where the recording was not performed. The signal level is compared with a comparator. Based on the comparison result of the comparator, the recording light power recorded in the land portion (or groove portion) is set in the recording light power setting circuit. A memory is connected to the recording light power setting circuit, and the recording light power value once set is temporarily stored in the memory and 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 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 reproduced signal waveform shown in FIG. FIG. 14 also shows the output waveform from the difference detection circuit.

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

  FIG. 17 shows another modification of the circuit shown in FIG. In the block diagram shown in FIG. 17, the reproduction waveform of the test signal is sampled and held at the timing of the PLL clock by a sample and hold circuit (S / H circuit), and further A / D converted to digitized amplitude in each magnetic domain. Get the data. D0 is the amplitude data of the magnetic domain data in the initialization direction (white) in the land portion recorded in the adjacent groove portion, and D1 is the amplitude data of the magnetic domain (80 in FIG. 9) in the recording direction (black). . D2 is the amplitude data of the magnetic domain data in the initialization direction (white) and D3 is the amplitude data of the magnetic domain in the recording direction (black) (82 in FIG. 9) in the adjacent groove portion where no recording is performed. . These data D3, D2, D1, and D0 are respectively stored in four memories in the MPU, and the arithmetic processing unit calculates (ΣD3−ΣD2) − (ΣD1−ΣD0) = ΔD, and the adjacent groove unit The difference ΔD in amplitude between the place where recording was performed and the place where recording was not performed is obtained. As shown in FIG. 17, when ΔD is not less than or equal to the predetermined value a, the recording light power is set again in the recording light power setting circuit, recording and reproduction are performed, and then the above calculation is performed again. Then, the above calculation is repeated while changing the recording light power until ΔD becomes equal to or less than a predetermined value a, whereby the proper recording light power for the groove portion can be set.

  In addition, using the circuit shown in FIG. 17, the MPU calculates the standard deviation of D0 to D3 because the S / N decreases and the jitter increases at the location affected by the cross light from the adjacent groove portion. You can compare it. Alternatively, the comparison may be performed using a difference in error rate instead of a difference in signal amplitude.

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

  In this step, the same operation as that in the second step is performed for three tracks in which the central groove portion is sandwiched between the land portions. First, the groove portion and the land portions adjacent to both sides thereof are initialized with a recording light power larger than that of 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 to both sides in the same direction as the magnetization direction initialized every about 10 bytes (see FIG. 9). At this time, the recording light power recorded in the land portion is increased or decreased around PL (0). For example, the power is sequentially changed to PG (0) -2.0 mW, PG (0) -1.0 mW, PG (0), PG (0) +0.1 mW, and PG (0) +0.2 mW for each sector. While recording the same test pattern.

  Thereafter, the central groove part is reproduced, and the appropriate power PL (1) is determined by comparing the amplitudes of the place where recording is performed on the adjacent land part and the place where recording is not performed. The appropriate power PL (1) is the same as that for determining the appropriate power PG (1), and the magnetic domain of the groove portion recorded on the adjacent land portion and the groove portion not recorded on the adjacent land portion. The maximum power at which the difference in amplitude of the reproduced signal from the magnetic domain is zero is assumed. In FIG. 12B, the ratio 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) and the magnetic domain of the groove portion not recorded on the adjacent land portion (relative). (Amplitude) and the recording light power recorded on the adjacent land portion. As shown in FIG. 12B, when the recording light power to the groove portion exceeds the appropriate power, the ratio (relative amplitude) of the reproduction signal from the groove portion decreases. The appropriate power detection method is the same as in the second step, and the circuit shown in FIG. 13, FIG. 15, or FIG. 17 can be used.

  Whether or not the proper recording light power PL (1) to the land portion determined in this way is optimal can be examined by obtaining 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 preset value, the second step is performed again using PL (1) to determine PG (2), and PG (2) is Using this, the proper recording light power PL in the third step is determined again.

[Example of operation procedure]
An example of an operation procedure for determining the optimum recording light power for recording in the land portion and the groove portion is shown in the flowchart of FIG. This flowchart starts when recording is performed on the 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 first process described above (steps 202 and 204). Next, an appropriate power PG (i) (i = 1) is determined using PL (0) according to the second step (step 206). Whether or not PG (i) is the optimum power depends on 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 number of repetitions and is usually 3-4). If i> N, the process ends abnormally (step 230).

  If i ≦ N, the land portion appropriate power PL (i) 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 optimum depends on whether or not | PL (i) −PL (i−1) | <ΔL (ΔL is a preset value, for example, 1 mW). Check (step 214). When satisfied and when PG (i) is optimal, the power of both PL (i) and PG (i) is optimal, and the process ends normally (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 If not satisfied, the routine proceeds to step 216, where i> N is determined.

  If i ≦ N in step 216, after i = i + 1 (step 218), the process returns to step 206, PG (i) is determined again, and the operation from step 208 is continued. If the condition is satisfied in step 208 and | PL (i-1) -PL (i-2) | <ΔL is satisfied, both optimum powers PL and PG are determined and the process ends normally (step 234). If i> N at 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 portion and the groove portion can be determined by various procedures. For example, values set in advance as PL (0) and PG (0) in the operation of the first step (steps 202 and 204) may be used. This set value can be stored in a memory or the like of a recording / reproducing apparatus (drive). When the optimum recording light powers PL (i) and PG (i) are once determined according to the flowchart, the optimum recording light powers PL (i) and PG (i) and 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 portion with the power PL (0), the power to be recorded on the groove portions on both sides thereof is changed to determine the appropriate recording light power of the groove portion, and the power on the groove portion is determined. The operation of recording the test pattern with PG (0) and changing the power to be recorded on the land portions on both sides thereof to determine the appropriate recording light power of the land portion was continuously performed. May be performed. Only one of the operations is effective in preventing cross light.

  It is preferable to execute the method for determining the optimum recording light power by the trial writing described in the above embodiment at the start of the operation of the recording / reproducing apparatus on which the land-groove type magneto-optical recording medium is mounted. Alternatively, the above method may be executed at intervals of 1 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 periphery or the outer periphery of the medium, the recording may be performed before the start of recording. When recording for a long time in order from the inner circumference or outer circumference by using ZCLV, it can be executed every time or every several zones at the zone boundary.

  In the first embodiment, the optimum power of the recording light of the land groove type magneto-optical recording medium is determined. In this embodiment, a method of simultaneously determining the optimum power of the reproducing light as well as the recording light by trial writing will be described.

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

[First Step: Recording Test Pattern A]
After positioning the optical head on the nth track (land portion) of the area where the test signal is recorded, the test is performed while increasing the recording optical 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 the power P0, the first block is recorded with the power P0 + Δ, the second block is recorded with the power P0 + 2Δ, and the mth block is recorded with the power P0 + mΔ. Recording is performed on each sector included in the same numbered block with laser light having the same power. The recording light power Pw of the mth block of the nth track is represented by Pw (n, m) = P0 + mΔ.

[Second Step: Recording Test Pattern B]
Next, recording is performed on each block of the land portion 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, the n + 1-th track and the n-1-th track. Test pattern B is recorded with the same power as the above power. 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 nth track is reproduced. The nth 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 reproduction 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 the blocks at each reproduction light power is displayed. Pr with the largest S can be set as the optimum reproduction light power Prbest, and it can be seen from the table results that Prbest = 2.0 mW. Further, the optimum recording light power Pwbest can be a 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, and therefore Pw = 7 mW is set as the optimum recording light power Pwbest as the central power. 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 each block of the nth track is recorded with the pattern A with the same recording light power, the error of each sector may be measured, and defective sectors may be excluded in advance. By doing this, it is possible to remove the error of the reproduction signal based on the initial defect such as a defect from the error due to the reproduction signal due to the cross light, and to determine the optimum recording and reproduction light power more accurately.

  In the fourth step, the total S of S (Pr) is obtained from all the blocks in each reproduction light power, and Pr having the maximum S is set as the optimum reproduction light power. The sum S ′ of S (Pr) from the reproduced signal is obtained, and the recording light power that gives 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. The optimum reproduction light power Prbest can be set to a power that maximizes S (Pr) at the optimum recording light power Pwbest, that is, 2.0 mW or 2.5 mW. When the optimum recording light power and optimum reproduction light power are selected 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 (nth track) and the test pattern B is recorded on the groove portions (n + 1th and n-1th tracks) on both sides thereof, and then the land portion is reproduced. The optimum recording and reproducing light power for the land portion was set 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 tracks) on both sides thereof. In accordance with the above, it is possible to detect the reproduction signal from the groove portion and determine the optimum power for recording and reproduction to the groove portion. That is, it is possible to determine the optimum recording and reproducing light power for the land part and the groove part, respectively, and to cope with the difference in the focus of the recording and reproducing light on the land part and the groove part.

  The operations in the first to fourth steps are repeated at a predetermined timing such as when the drive is started. When 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 decrease the recording light power in the first step. For example, the recording light power Pw (n, m) = P0 + mΔ of the nth 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 the test writing is performed, the maximum recording light power portion is distributed to two blocks in the same track, so that the test writing area is less deteriorated.

Modification of Example 2 A modification of Example 2 is shown in FIG. In the second step of the second embodiment, the test pattern B is recorded with the same recording light power on the groove portions adjacent to both sides of the land portion where the test pattern A is recorded. However, in this modification, the groove portions adjacent to both sides are recorded. An example is shown in which test patterns are recorded with different recording light powers. FIG. 27 is a sector arrangement diagram of an area in which a test pattern of a land / groove type optical recording medium is recorded (test writing is performed), and sectors N, N + 1, N + 2,. Assume that tracks m, m + 1, m + 2,... M + R are arranged in the vertical direction. Test patterns are recorded with different recording light powers in the sectors of each track.

  For example, the recording optical power is changed at a constant change rate so that Wr10 <Wr11 <Wr12 <Wr13... <Wr1Q, Wr1Q <Wr10, Wr10 <Wr20 <Wr30 <Wr40. And increase according to 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 sectors are recorded with different recording light powers, for example, the Nth sector of the (m + 1) th track (for example, the land portion) and the mth track adjacent thereto (in this case, the groove) Part) and the (m + 2) th track (in this case, the groove part) are recorded with different recording light powers. In this case, cross-write occurs depending on the relationship of the recording light power between adjacent sectors. Then, as in the second embodiment, the reproducing optical power is modulated to various values for each sector and reproduced.

  When the reproducing optical power is modulated to various values for each sector, the reproducing optical 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 optimum reproduction light power can be determined by the method as described above. The optimum recording light power can be obtained by taking the average of the recording light power of the sectors on both sides of the sector with the lowest error rate. In this modification, the test area can be reduced and the test time can be shortened 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 of performing magneto-optical recording 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 that can be reproduced by magnetic super-resolution. It is. The magnetic super-resolution reproduction method can dramatically improve the optical resolution by utilizing the temperature characteristic of the mask layer. That is, even a minute magnetic domain having a size less than ½ of the spot diameter of the reproduction light can be reproduced independently. However, the mask shape of the mask layer that masks 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 lowered. Therefore, the method of this embodiment is applied to a magneto-optical recording medium that can be reproduced by magnetic super-resolution, and the optimum power intensity of reproduction light of magnetic super-resolution is obtained using a table as shown in FIG. be able to. Thereby, a high resolution and high S / N reproduction signal can be obtained from a land-groove magneto-optical recording medium of the magnetic super-resolution reproduction system.

  In Examples 1 and 2, test pattern test writing was performed to determine the optimum recording power and optimum reproduction power. In this embodiment, a recording / reproducing method of a magneto-optical recording medium capable of preventing deterioration due to excessive use of the test writing area will be described.

  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 nth track of the optical recording medium as shown in FIG. In the figure, there are a plurality of trial writing areas in the nth track, and a data area is arranged behind each trial writing area. In the present invention, auxiliary information for selecting one trial writing area from a plurality of trial writing areas is recorded in an area different from the trial writing area. In addition, the user is prevented from recording user data at the auxiliary information address.

  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 simplicity, it is assumed that there are only the trial writing area A and the trial writing area B as the plurality of trial writing areas, and examples of the two types of auxiliary information shown in FIGS. 22A and 22B are shown. It will be explained while using.

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

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

  A procedure for selecting one test writing area from the two areas of the test writing area A and the test writing area B using the auxiliary information shown in FIG. 22A will be described with reference to FIGS. 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 trial writings using the trial writing area A in which the trial writing is permitted becomes equal to or larger than the preset number, the further writing to the trial writing area A is not permitted. 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 trial writings using the trial writing area where trial writing is allowed is larger than the preset number of times, another trial writing area that has not been trial writing in the past, Auxiliary information is rewritten so that trial writing is allowed as a new trial writing area. Here, when CNT_A reaches hexadecimal FFFF, FLG_B is changed from “0” to “1”. Next, trial writing is performed in the trial writing area B until the number of trial writings reaches the upper limit as in the area A. When the number of trial writings in the area B reaches the upper limit, FLG_B is rewritten to “0” again, and trial writing is performed in the next trial writing area (C).

  In this way, each trial writing area has an upper limit on the number of trial writings, so the trial writing is repeated many times before the recording medium is thermally damaged and the recording characteristics change. The test writing area can be used. Therefore, trial writing can be performed using a trial writing area having stable recording characteristics, and the recording conditions can be optimized.

  On the other hand, FIG. 22B includes the number of times CNT that trial writing has been performed using the trial writing area in which trial writing is allowed, and information DST that designates the trial writing area in which trial 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”, trial writing area A is used, and when DST is “2”, trial writing is performed using trial writing area B. When the number of trial writings CNT using the trial writing area in which trial writing is allowed is larger than the preset number of times, another trial writing area that has not been trial-written in the past is replaced with a new one. The auxiliary information is rewritten so that the trial writing can be permitted as the trial writing area. Here, when CNT reaches hexadecimal FFFF, DST is changed from “1” to “2”, and the test writing area to be used is changed from the test writing area A to the test writing area B. Corresponds. In this way, each trial writing area has an upper limit on the number of trial writings, so it is possible to avoid repeated recordings and causing thermal damage to the recording medium and changes in recording characteristics. The stable test writing is possible as in the case of FIG.

  In the description of FIG. 21, it is assumed that a plurality of test write areas are provided on the same track. However, a plurality of test write areas may be provided on the same sector, and are included in the scope of the present invention. .

  In the first to third embodiments, a test reading area can be provided in the vicinity of the test writing area or a part of the test writing area. In the trial reading area, recording magnetic domains with different recording frequencies are recorded at the time of shipment. The trial reading area is an area that a normal user cannot erase or record. Using the reproduction condition setting signal recorded in the trial reading area, jitter can be measured based on the clock mark, and the amplitude of the reproduction signal can also be evaluated. Also, the bit error rate may be measured. Using the results of these trial readings, it is possible to optimally adjust the reproduction laser output, irradiation timing, etc., if necessary, the application timing and intensity of the external magnetic field, and reproduce user data under such optimum conditions. Become. The reproduction condition setting signal to the trial reading area can be made by the manufacturer before shipment. In magnetic super-resolution and land / groove recording, it is desirable that the playback conditions are optimized. For these applications, information including the playback conditions is recorded in advance on the medium, and it is possible to test and read it. It is particularly effective.

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

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

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

  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 apparatus of the present invention is a suitable apparatus for executing the optimum recording light quantity determination method and the optimum recording / light quantity determination method of the present invention, and by recording and reproducing information with the determined optimum light quantity. In addition, there is no cross light between lands and grooves of a land / groove type optical recording medium, and high S / N reproduction can be realized.

It is a figure which shows the whole structure of the recording / reproducing apparatus for the land groove type magneto-optical recording media used in the Example of this invention. 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. FIG. 6 is a diagram for explaining a method for determining PL (0) in the first step of Embodiment 1, and is a timing chart showing the relationship between a recording laser pulse, a recording external magnetic field, a recording magnetic domain, and a signal reproduced therefrom in the optical magnetic field recording method. It is. FIG. 3 is a diagram illustrating a relationship between a reproduction signal from a recording magnetic domain recorded in a first step of Example 1 and a recording laser power. 6 is a graph showing the relationship between 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 and laser recording power. It is a block diagram of a detection system for obtaining Δ1 in an example. 1 is a plan view of a land groove type magneto-optical disk showing a test recording area in which 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 in which a test signal is recorded by a magneto-optical recording method in an embodiment of the present invention. FIG. FIG. 6 is a diagram illustrating a recording magnetic domain pattern and a reproduction signal waveform obtained from a land portion when recording is performed with overpower on a groove portion sandwiching the land portion in the second step of Example 1; FIG. 6 is a diagram illustrating a recording magnetic domain pattern and a reproduction signal waveform obtained from the land portion when recording is performed with appropriate power on the groove portion sandwiching the land portion in the second step of Example 1; FIG. 6 is a diagram illustrating a recording magnetic domain pattern and a reproduction signal waveform obtained from a land portion when recording is performed with under power on a groove portion sandwiching the land portion in the second step of Example 1. FIG. 12A is a graph showing the relationship between the relative amplitude from the magnetic domain of the central track with the power of PL (0) and the recording power in which the magnetic domain is recorded on the adjacent track. FIG. 12A shows the case where the central track is a land. FIG. 12B shows the result when the central track is a groove. 3 is a diagram illustrating a circuit for determining a recording power PG (i) used in Embodiment 1. FIG. It is a timing chart which shows the signal waveform after the subtraction which shows the sample hold pulse and timing pulse used for the circuit of FIG. 13, and the output from a difference detection circuit. 6 is a diagram illustrating another example of a circuit for determining the recording power PG (i) used in Embodiment 1. FIG. 16 is a timing chart showing sample hold pulses and timing pulses input to the circuit of FIG. FIG. 6 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 exemplary embodiment. FIG. 6 shows track blocks and sector divisions of the land-groove type optical recording medium used in Example 2 and test patterns A / B recorded in each sector. 10 is a table showing various recording light powers used when recording a test pattern in each block in Example 2 and combinations of various reproducing light powers used when reproducing a test pattern recorded with each recording power. FIG. 10 is a diagram conceptually showing a part of the nth track of the optical recording medium used in Example 3. It is a conceptual diagram which shows the content of the auxiliary information stored in the nth track | truck shown in FIG. 21, and shows the content of two types of auxiliary information ((a) and (b)). 24 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. FIG. 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. It is a table which shows the relationship between the content of the auxiliary information shown to Fig.22 (a), and the test writing area | region used. It is a table which shows the relationship between the content of the auxiliary information shown in FIG.22 (b), and the test writing area | region used. FIG. 10 is a diagram conceptually showing an arrangement of sectors of a land-groove type optical recording medium used in a modification of Example 2.

Explanation of symbols

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 portion 94, 114 Groove portion 110 Recording magnetic domain 322 Clock source 324 Test data timing generation circuit

Claims (14)

A method for determining the optimum recording and reproduction light quantity of a land groove type optical recording medium,
A first step of recording a test pattern with a different recording light amount in each of a plurality of areas of a land part or a groove part;
A second step of recording a test pattern with a different recording light amount in each of a plurality of regions of the groove portion or land portion adjacent to both sides of the plurality of regions of the land portion or groove portion;
A third step of reproducing each of the plurality of test patterns recorded in the first step with various reproduction light amounts;
The reproduction light from the region that produces the reproduction signal with the least error among the plurality of reproduction signals with various reproduction light quantities from the plurality of test patterns reproduced in the third step is set as the optimum reproduction light quantity, and the reproduction signal with the least error. And a fourth step of setting the recording light quantity recorded in the region that produces the optimum recording light quantity to determine the optimum recording and reproduction light quantity of the land groove type optical recording medium. In the fourth step, the error of the reproduction signal from the test pattern recorded and reproduced by the combination of various recording light amounts and reproduction light amounts reproduced in the third step is obtained, and the errors are summed for each reproduction light amount. Thus, the optimum reproduction light quantity is obtained by setting the reproduction light quantity with the smallest total error as the optimum reproduction light quantity, and setting the recording light quantity that generates the reproduction signal with the least error among the reproduction signals reproduced with the optimum reproduction light quantity as the optimum recording light quantity. The method for determining the optimum recording and reproducing light amount of the 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 summed for each recording light amount. Therefore, the recording light quantity with the smallest total error is the optimum recording light quantity, and the reproduction light quantity that generates the reproduction signal with the least error among the reproduction signals from the test pattern recorded with the optimum recording light quantity is the optimum reproduction light quantity. The method for determining the optimum recording and reproduction light quantity of the land-groove type optical recording medium according to claim 1, wherein the optimum recording light quantity and the optimum reproduction light quantity are determined by means of: In the first step, the land portion or groove portion of the nth track is divided into B areas, and the recording light quantity Pw (n, m) = P0 + mΔ is recorded in the mth area (0 ≦ m ≦ B) ( Here, P0 is the recording light quantity recorded in the area of m = 0, and Δ is the change rate of the recording light quantity).
In the second step, the groove or land of the (n + 1) th and (n-1) th tracks is divided into B areas, and the recording light amount Pw for recording in the mth area (0 ≦ m ≦ B) of the (n + 1) th track. Is Pw (n + 1, m) = P0 + mΔ, and the recording light quantity Pw recorded in the mth area (0 ≦ m ≦ B) of the (n−1) th track is Pw (n−1, m) = P0 + mΔ. A method for determining the optimum recording light and reproduction light amount of the land-groove type optical recording medium according to claim 1. Each area includes a plurality of sectors in the first step, the plurality of sectors in the same area are recorded with the same recording light quantity, and the total number of sectors in which the number of errors in the sector does not exceed the reference value in the fourth step 2. The land groove according to claim 1, wherein S (Pr) is obtained in each area, and the reproduction light quantity having the largest total S of the areas reproduced with the same reproduction light quantity is set as the optimum reproduction light quantity. Of determining the optimum recording and reproduction light quantity of a type optical recording medium. The optical recording medium has a plurality of areas for recording the test pattern, and when recording a test pattern, auxiliary information for selecting one test pattern recording area from the plurality of test pattern recording areas, 6. The land groove type optical recording medium according to any one of claims 1 to 5, wherein the optimum recording and reproduction light amount determination method is performed. 7. The land groove type optical recording medium according to claim 6, wherein the auxiliary information includes information capable of determining whether or not recording in each test pattern recording area is permitted. And a method for determining the reproduction light quantity. 8. The land-groove 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 test pattern recording is allowed. A method for determining the optimum recording and reproduction light quantity of a medium. Using the test pattern recording area where the test pattern recording is allowed, when the number of times the test pattern is recorded is larger than the preset number, further writing to the test pattern recording area is allowed. 9. The method for determining the optimum recording and reproducing light quantity of a land-groove type optical recording medium according to claim 8, wherein the auxiliary information is rewritten so as not to occur. When the test pattern recording area where the test pattern recording is allowed is used and the number of times the test pattern is recorded is larger than the preset number, another test pattern has not been recorded in the past. 10. The optimum recording and reproduction light quantity of the land groove type optical recording medium according to claim 9, wherein the auxiliary information is rewritten so that the test pattern recording area can be used as a new test pattern recording area and recording of the test pattern is allowed. How to determine. 11. The land groove type optical recording medium according to any one of claims 6 to 10, wherein a plurality of test pattern recording areas are provided on the same track. Method for determining the optimum recording and reproducing light quantity of land-groove type optical recording medium according to any one of 請 Motomeko 6-11 you characterized by having a recording area of a plurality of test patterns on the same sector. A land / groove type optical recording medium recording / reproducing method for recording and reproducing information with the recording light quantity and the reproduction light quantity 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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