JPH08203080A - Write test method and optical information recording and reproducing device - Google Patents

Abstract

PURPOSE: To exactly record a recording pit regardless of temp. change in an optical information recording and reproducing device and the contamination of an objective lens and a recording medium. CONSTITUTION: A prescribed signal is recorded in the write test region of a magnetooptical disk 1 by changing a recording power, a power level just before starting the state of a high temp. level of the disk 1 is detected based on the amplitude of the reproduced signal and a power level forming the state of a low temp. level and a power level forming the state of a high temp. level are determined based on the detected power level just before starting the state of high temp. level. This device is provided with a means for recording a prescribed signal in the write test region of the disk 1, a means for detecting the amplitude of the reproduced signal of the recorded signal, a means for detecting the power level just before starting the state of high temp. level based on the amplitude of the reproduced signal and a means for determining the power level forming the state of the low temp. level and the power level forming the state of the high temp. level based on the detected power level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a write test method and an optical information recording / reproducing apparatus for setting a recording power for recording information on an optical information recording medium to an optimum value.

[0002]

2. Description of the Related Art Conventionally, as a device for irradiating a recording medium with a light beam to optically record or reproduce information, a reproduction-only device for reproducing a reproduction-only recording medium in which information is recorded in advance, A write-once type device that records information pits by opening the recording film with heat, a device that records information by changing the crystal state of the medium and the reflectance thereof, and an information pit that changes the magnetization direction of the perpendicular magnetization film. There is a rewritable device for recording.

FIG. 13 is a block diagram showing an example of a rewritable magneto-optical disk device. In FIG. 13, reference numeral 1 is a magneto-optical disk which is an information recording medium, and a magnetic film 2 is formed on a transparent substrate such as glass or plastic. The magneto-optical disk 1 is mounted on the rotating shaft of a spindle motor 3 and is rotated at a predetermined speed by driving the spindle motor 3. The optical head 4 is arranged on the lower surface of the magneto-optical disk 1, and the optical head 4 is arranged on the upper surface.
Bias magnet 13 is arranged opposite to.

A semiconductor laser 5 as a recording / reproducing light source is provided in the optical head 4. When recording information, the light beam of the semiconductor laser 5 is modulated by a laser driving circuit (not shown) according to an information signal. . The light beam emitted from the semiconductor laser 5 is collimated by the collimator lens 6 and then transmitted through the polarization beam splitter 7 to pass through the objective lens 8
Incident on. The incident light beam then passes through the objective lens 8
And the light is focused on the magnetic film 2 of the magneto-optical disk 1 as a minute light spot. On the other hand, the bias magnet 13
From this, a magnetic field in a fixed direction is applied to the magneto-optical disk 1, and a series of information is recorded by the application of this magnetic field and the irradiation of the modulated light beam.

A part of the light beam applied to the magneto-optical disk 1 is reflected by the medium surface. This reflected light again passes through the objective lens 8 and enters the polarization beam splitter 7,
The light is reflected by the plane of polarization toward the beam splitter 9 and separated from the incident light from the semiconductor laser 5. The beam splitter 9 splits the incident light beam into two light beams, and one light beam is received by the optical sensor 11 via the sensor lens 10. The light reception signal of the optical sensor 11 is input to the AT / AF circuit (auto tracking, auto focus control circuit) 12, and A
The T / AF circuit 12 generates a tracking error signal and a focus error signal based on the received light signal. Then, the objective lens actuator 14 is driven based on the obtained tracking error signal and focus error signal to displace the objective lens 8 in the tracking direction and the focus direction, thereby performing tracking control and focus control.

On the other hand, when the recorded information on the magneto-optical disk 1 is to be reproduced, the light beam of the semiconductor laser 5 is set to a reproduction power which cannot be recorded, and recording is performed by scanning the reproduction light beam to a target track. Information is reproduced. That is, the reflected light of the reproduction light beam from the disc surface is received by the optical sensor 16 via the objective lens 8, the polarization beam splitter 7, the beam splitter 9, and the sensor lens 15. The light reception signal of the optical sensor 16 is sent to a reproduction signal processing circuit (not shown), and the recorded information is reproduced by performing a predetermined signal processing there. Of course, during reproduction, the reflected light of the reproduction light beam is received by the optical sensor 11,
The F circuit 12 performs tracking control and focus control based on the received light signal.

[0007]

The magneto-optical disk device described with reference to FIG. 13 is a device by overwriting of the optical modulation system as described above, and erases information in order to meet the demand for high-speed recording of information. And recording can be performed simultaneously. In recent years, pit edge recording, in which information is provided on both edges of recording pits, has become mainstream in order to increase the density of information.

However, it is necessary to record the recording pits accurately and stably in order to speed up the recording of information and increase the density of information as described above. However, the temperature change in the apparatus at the time of recording, the objective lens and the disc The recording power fluctuates due to dirt on the disc. Therefore, conventionally, there has been a problem that the recording pits change due to the fluctuation of the recording power, and it is not possible to sufficiently cope with the speeding up and the density increasing of the recording.

The present invention has been made in view of the above conventional problems, and an object thereof is to detect a power level immediately before the start of a high temperature level state and to form a low temperature level state based on the detected power level. By determining the power level for forming the high temperature level state, the write test method and the optical information can be recorded accurately so that the recording pit can be accurately recorded irrespective of the temperature change in the device and the dirt of the objective lens and the recording medium. It is to provide a recording / reproducing apparatus.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to record a predetermined signal by changing the recording power in a write test area of an information recording medium, and to determine the high temperature level state of the recording medium based on the reproduced signal amplitude. The power level immediately before the start of the high temperature level state is detected, and the power level for forming the low temperature level state and the power level for forming the high temperature level state are determined based on the detected power level immediately before the high temperature level state starts. It is achieved by a light test method characterized by:

Further, an object of the present invention is to provide an optical information recording / reproducing apparatus for recording information by controlling the recording power of a light beam on an optical information recording medium by multilevel control, in a write test area of the recording medium. Means for recording a predetermined signal, means for detecting the reproduction signal amplitude of the recorded signal, and detection of the power level immediately before the start of the high temperature level state of the recording medium based on the reproduction signal amplitude And a means for determining a power level for forming the high temperature level condition and a power level for forming the low temperature level condition based on the power level immediately before the detected high temperature level condition begins. It is achieved by an optical information recording / reproducing apparatus characterized by:

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the optical information recording / reproducing apparatus of the present invention. In FIG. 1, the same parts as those of the conventional device of FIG. That is, in FIG. 1, the magneto-optical disk 1, the magnetic film 2, the spindle motor 3, and the AT / AF circuit 12 are the same as those in FIG. Also in the optical head 4, the semiconductor laser 5, the collimator lens 6, the objective lens 8, the polarization beam splitters 7 and 9, and the sensor lens 10 are also included.
And 15, the optical sensors 11 and 16, and the objective lens actuator 14, and are configured the same as the optical head 4 of FIG. The optical head 4 is configured to move in the radial direction of the magneto-optical disk 1 by a mechanism (not shown) so that a desired information track can be accessed.

Further, in the present embodiment, the amplitude detection circuit 17 for detecting the amplitude of the reproduction signal obtained by the optical sensor 16.
Is provided. The amplitude detection circuit 17 uses the magneto-optical disk 1 when performing a write test as described later in detail.
The amplitude of the reproduction signal is detected in order to detect the power (PHth) immediately before the high temperature process (1) is started. The amplitude value of the reproduction signal is calculated by the A / D converter in the CPU 18
Taken in 8. The asymmetry detection circuit 19 is a circuit for detecting asymmetry (symmetry) of reproduced signals of two recording pits having different lengths during a write test as described later. Inside the asymmetry detection circuit 19,
A slice level automatic tracking circuit is provided to detect the peak value and bottom value of the reproduced signal and always set the intermediate value to the slice level, and the intermediate value (slice level) of the reproduced signal of a predetermined long mark and short mark is provided. ) Are respectively detected and the difference is output as asymmetry. The output of the asymmetry detection circuit 19 is also taken into the CPU 18 by the A / D converter.

The CPU 18 is a processor circuit which constitutes a main control unit of the optical information recording / reproducing apparatus of this embodiment, and is an AT.
An information recording operation by controlling the AF circuit 12, the drive circuit (not shown) of the bias magnet 13, the drive circuit (not shown) of the spindle motor 3, the semiconductor laser drive circuit 20 for driving the semiconductor laser 5, and the like. And control the playback operation. As will be described later in detail, the CPU 18 controls each part to perform a write test when the magneto-optical disk 1 is replaced, and controls the recording power of the semiconductor laser 5 to the optimum power.

FIG. 2 is a diagram showing a lighting waveform of the semiconductor laser 5 of this embodiment. FIG. 2 shows, as an example, a laser lighting waveform when a 4T pattern is recorded. In FIG. 2, PL is a power level for forming a low temperature level state (erasure) in the recording layer of the magneto-optical disk, PH1 and P1.
H2 is a power level for forming a high temperature level state (recording). Further, Pr is a reproducing power, which is a constant value. In this embodiment, as shown in FIG. 2, PL, PH1, PH
It is assumed that the recording power of the semiconductor laser 5 is controlled by four values of 2 and Pr, and these PL and PH are
The values of 1 and PH2 are respectively set to optimum values.

Next, the write test method of this embodiment will be described in detail with reference to FIGS. 3, 4 and 5. First, the write test of this embodiment is roughly divided into the following three steps. (1) In order to determine the laser power level PL for creating the low temperature level state, the laser power PHth immediately before the high temperature state starts is calculated. (2) Laser power level P that creates a high temperature level state
Calculate the ratio of H1 and PH2. (3) The recording power is changed while keeping the ratio of PH1 and PH2 constant to obtain the absolute values of PH1 and PH2.

First, the method (1) for obtaining the laser power level PL will be described. In FIG. 3, when performing a write test, the CPU 18 accesses the optical head 4 to a predetermined write test area of the magneto-optical disk 1 (S
1). Next, in the CPU 18, the bias magnet 13
The drive circuit and the semiconductor laser drive circuit 20 are controlled to apply an erasing bias magnetic field to the write test area, and the erasing light beam is scanned to erase the write test area (S2). When the erasing is completed, the CPU 18 sets the initial value Pw of the recording power of the semiconductor laser 5 (S
3). This is set as an initial value using, for example, the PL recorded on the control track of the magneto-optical disk 1.

When the initial value of the recording power is determined, the CPU 1
8 records an 8T continuous pattern in the write test area with the power of the initial value (S4), and then reproduces the recorded 8T continuous pattern to detect the amplitude level of the reproduction signal (S).
5). Of course, the amplitude level of this reproduction signal is detected by the amplitude detection circuit 17. The obtained amplitude level is CPU1
It is taken into the CPU 18 by the A / D converter in 8 and stored in the internal memory (S5). When the recording and the reproduction with the initial values are completed in this way, the CPU 18 sets the recording power Pw to ΔP.
The w is added to increase the recording power (S6), the 8T continuous pattern is recorded again in the write test area with this recording power (S4), and it is reproduced to detect and store the amplitude level of the reproduced signal (S5). .

When the recording power is increased by a predetermined amount until the predetermined recording power reaches a predetermined recording power in this way, the relationship between the recording power and the reproduction signal amplitude is shown in FIG. You can get the data.
The predetermined recording power may be determined to be, for example, twice the PH recorded on the control track of the disc. Referring to FIG. 6, when the recording power is low, the reproduction signal amplitude is almost 0, and there is a tendency that the reproduction signal amplitude sharply rises from a certain recording power. The recording power at which the reproduction signal amplitude rises is the laser power PHth immediately before the start of the high temperature level state to be obtained.

Here, PHth immediately before the start of the high temperature level state described with reference to FIG. 6 has the characteristic that it changes according to the temperature change due to the medium characteristics. Therefore, the present invention pays attention to this characteristic, and based on PHth, PL, PH1, PH
By determining 2, the recording power is set according to the temperature change. The CPU 18 calculates the PH based on the data of the recording power and the reproduction signal amplitude stored in the memory.
The th is obtained and stored in the memory (S7). With the above, the processing for obtaining PHth in (1) is completed. In this example,
The (1-7) code is adopted as the modulation method of the recording information, and the longest pit at this time, 8T, is used for detecting the reproduction signal amplitude.

Next, the method of obtaining the ratio of the laser power levels PH1 and PH2 that produces the high temperature level (2) will be described. Continuing to refer to FIG. In FIG. 3, first, the CPU 18 sets the value of the laser power level PL that creates the low temperature level state using the previously obtained PHth as PL = α × PHth (S8). However, the condition of α is PLmin / PHth <α <1.0. With the above, the value of PL is determined. Subsequently, the CPU 18 sets the laser power level PH1 = PHth that creates a high temperature level state (S9), and records PH8 = PH2 in the write test area of the magneto-optical disk 1 as PH1 = PH2 (S10). That is, the recording conditions at this time are PL = α × PHth and PH1 = PH2 = PHth. For PL, the value obtained previously is used.

When the 8T continuous and 2T continuous patterns are recorded, the CPU 18 controls each part to reproduce it, and the slice level SL (8T), 2T of the reproduced signal of the 8T pattern.
The slice level SL (2T) of the pattern reproduction signal is detected (S11). That is, the asymmetry detection circuit 19
Then, the intermediate value between the peak value and the bottom value of the reproduced signal of the 8T continuous pattern and the 2T continuous pattern is detected.
Next, the asymmetry detection circuit 19 detects the difference ΔSL between the slice level SL (8T) of the reproduction signal of the 8T continuous pattern and the slice level SL (2T) of the reproduction signal of the 2T continuous pattern (S12), and the CPU 18 detects this ΔS.
It is determined whether L is 0 (S13). If ΔSL is not 0, the CPU 18 adds ΔPH1 to PH1 and records an 8T continuous and 2T continuous pattern again in the write test area (S10), and similarly reproduces it to detect an 8T slice level and a 2T slice level ( S11), detection of the difference ΔSL between the two slice levels (S12), Δ
It is determined whether SL is 0 (S13). CP
U18 repeats the processing of S10 to S14 as described above to increase the value of PH1 by ΔPH1 and ΔSL becomes 0.
The value of PH1 when is reached is stored in the memory.

Here, in this embodiment, as described above, (1
-7) The code is used to record the signal of 8T which is the longest pit and the signal of 2T which is the shortest pit, and the slice level (the intermediate value between the peak value and the bottom value) of the two reproduction signals of the longest pit and the shortest pit. ) Difference ΔSL is detected. Then, it is determined whether or not this ΔSL is 0, and the value of PH1 when it becomes 0 is stored in the memory. This will be described. FIG. 7 shows reproduction signals of 8T continuous and 2T continuous patterns. The reproduction signal of 8T of the longest pit is saturated as shown in FIG. 7, and in this state, the intermediate value (slice level) between the peak value and the bottom value is 0. Can be regarded as

Therefore, the value of PH1 is changed to ΔS so that 2T can be recorded in 2T having an accurate length based on 8T.
PH1 is detected when L becomes 0. That is, 8
Since the slice level of the reproduced signal of T can be regarded as 0, if the difference ΔSL between the slice levels of the reproduced signals of the pits of 8T and 2T is 0, the slice level of the reproduced signal of 2T can also be regarded as 0. . Therefore, this means that the pit of 2T could be accurately recorded in the length of 2T. Therefore, the value of PH1 at this time is 2 of the shortest pit.
This is the power level of PH1 for accurately recording T.

Next, the CPU 18 outputs the obtained PH1 to PH.
1 ', and processing for obtaining the value of PH2 that matches the value is performed. Since S13 of FIG. 3 continues from S14 of FIG. 4, it will be described with reference to FIG. First, as described above, PH1 = P
H1 ′, and the initial value of PH2 is PH2 = 0.8 × P
It is set to H1 '(S14). The value obtained previously is used for PL. Next, the CPU 18 controls each part under this recording condition to record 8T continuous and 2T continuous patterns in the write test area (S15), and thereafter reproduces the slice level SL (8T) 'of the reproduced signal of the 8T continuous pattern. Two
Slice level SL (2
T) 'is detected (S16). Of course, this is detected by the asymmetry detection circuit 19 and taken into the CPU 18. Subsequently, the asymmetry detection circuit 19 detects the difference ΔSL ′ between the slice levels SL (2T) ′ and SL (8T) ′ (S17), and the CPU 18 determines whether or not the obtained ΔSL ′ is 0 ( S18).

In this case, if ΔSL 'is not 0, CP
U18 adds ΔPH2 to PH2 (S19), and again records the 8T continuous and 2T continuous patterns in the write test area. Then, play it again and the 8T slice level S
Detection of L (8T) 'and 2T slice level SL (2T)' (S16), and difference ΔS between the two slice levels
L'is detected (S17), and it is determined whether ΔSL 'is 0 (S18). The CPU 18 repeats the processing of S15 to S19 to increase the value of PH2 by ΔPH2 and ΔS.
The value of PH2 when L'becomes 0 is stored in the memory as PH2 '(S20). Next, the CPU 18 calculates a ratio β (β = PH2 ′ / PH1 ′) between the obtained PH2 ′ and the PH1 ′ previously stored in the memory (S2).
1). This is the end of the process (2) for obtaining the ratio of PH2 and PH1.

Here, in FIG. 4, the difference in slice level Δ between the reproduction signals of 8T and 2T is obtained by changing PH2 as described above.
The value of PH2 when SL 'is 0 is detected. This will be described. In this case, the power level of PH2 capable of recording the longest pit of 8T with an accurate length of 8T with reference to 2T is detected. In other words, for the shortest 2T pit, the value of PH1 that can be recorded to an accurate length was previously obtained, so this time when PH2 is changed and the difference ΔSL ′ between the slice levels of the reproduced signals of 8T and 2T becomes zero. PH2
Is to detect. That is, if ΔSL ″ is 0, the slice level of the reproduction signal of 8T can be regarded as 0, which means that an 8T pit can be recorded in an accurate length of 8T.
Is the power level of PH2 that can accurately record the longest 8T pit.

Finally, the method (3) of changing the recording power while keeping the ratio of PH1 and PH2 constant to obtain the absolute value will be described. S21 of FIG. 4 is S2 of FIG.
Since it follows No. 2, it will be described below with reference to FIG. In FIG. 5, first, the CPU 18 sets PH1 = PHth and PH2 = β × PH1 as initial values of PH1 and PH2 (S22). PHth is S7 in FIG. 3 and β is S2 in FIG.
It was obtained in 1. The value obtained previously is used for PL. Next, the CPU 18 controls each unit to perform 8T in the write test area of the magneto-optical disc 1 under the recording condition of the initial value.
A continuous 2T continuous pattern is recorded (S23) and then reproduced to detect the slice level SL (8T) ″ of the reproduced signal of the 8T continuous pattern, and the slice level SL (2T) ″ of the reproduced signal of the 2T continuous pattern. Yes (S24).
Of course, this is detected by the asymmetry detection circuit 19. Then, the asymmetry detection circuit 19 obtains the difference ΔS between the slice levels SL (2T) ″ and SL (8T) ″.
L ″ is detected (S25), and the CPU 18 determines this ΔSL ″.
Is determined to be 0 (S26). Where ΔS
If L ″ is not 0, the CPU 18 sets PH1 = PH.
1 + ΔPH1, PH2 = β × PH1 and PH1 and PH
The recording power is updated while keeping the ratio of 2 constant (S2
7).

The CPU 18 again records 8T continuous and 2T continuous patterns in the write test area under the updated recording conditions (S23), and then reproduces them to detect slice levels of 8T continuous patterns and 2T continuous patterns (S2).
4), the difference ΔSL ″ between the two slice levels is detected (S25), and it is determined whether ΔSL ″ is 0 (S26). The CPU 18 should repeat the processing of S23 to S27 in this way to increase the recording power by a predetermined amount while keeping the ratio of PH1 and PH2 constant, and obtain the values of PH1 and PH2 when ΔSL ″ becomes zero. PH1, PH
Determined as 2. PL and P by light test
The values of all the optimum power levels of H1 and PH2 are obtained,
Finish the light test.

Even when the absolute values of PH1 and PH2 are calculated as described above, pits of 2T and 8T are recorded and 2T is recorded.
The values of PH1 and PH2 when the difference ΔSL ″ between the slice levels of the 8 and 8T reproduction signals become 0 are determined as the optimum power levels. This is also based on the reason explained above, and the longest pit If the difference ΔSL ″ between the slice levels of the reproduction signal of 8T of 2T and the reproduction signal of 2T of the minimum pit is 0, 8
The slice level of the reproduced signals of T and 2T is 0, so that both pits can be recorded in accurate lengths. Therefore, the values of PH1 and PH2 at this time can accurately record 2T of the shortest pit and 8T of the longest pit.
And the power level of PH2.

Here, when the linear velocity differs depending on the recording radial position of the disk as in the CAV system, for example, the recording power of the semiconductor laser needs to be changed accordingly. FIG. 8 shows the recording radius position (linear velocity) of the disc in this case.
And the recording power are shown, and there is a proportional relationship between the linear velocity and the recording power. Therefore, in such cases,
The write test described with reference to FIGS. 3 to 5 is performed, for example, on the inner circumference, the middle circumference, and the outer circumference of the disk, and P obtained at each position
It is assumed that the values of L1, PH1 and PH2 are stored in a memory, and the values of PL, PH1 and PH2 are changed according to the radial position of the disk by linear approximation based on the values. The write test as described above may be performed every time the disc is replaced, may be performed before recording information, or may be performed periodically at regular intervals.

Next, another embodiment of the present invention will be described. This embodiment is the same as the write test method of the previous embodiment in (1) and (3), but is different in the method of obtaining PH2 in (2). In this embodiment, after obtaining PL1 and PH1 by the method of FIG. 3, PH2 is obtained by the following method.

Specifically, the PH obtained in FIG. 3 is obtained.
1 is PH1 ', and the initial value of PH2 is PH2 = 0.8 × P
H1 'is set (PL is set to the value obtained previously), and 6T is applied to the write test area of the magneto-optical disk with this recording power.
And record the 8T signal. When recording is completed, the CPU
Reference numeral 18 reproduces the recorded signal, detects the amplitude values of the 6T and 8T reproduced signals, and stores them in the memory. Of course, the reproduction signal amplitude is detected by the amplitude detection circuit 17,
The detection result is loaded into the CPU 18. CPU18 is PH1
Recording power of 6T and 8T and amplitude detection of the reproduced signal are repeated by changing the recording power while keeping the ratio of PH2 and PH2 constant, and the data of the reproduced signal amplitude of 6T and 8T with respect to the change of PH2 is stored in the memory. Store it.

FIG. 9 shows the reproduction signal amplitude data of PH2, 6T, and 8T at this time. As is apparent from FIG. 9, the reproduction signal amplitudes of 6T and 8T are the same when PH2 is low, but there is a difference between the reproduction signal amplitudes of 6T and 8T. The CPU 18 determines the power at which the difference between the two reproduced signal amplitudes starts to be PH2 '. By the way, the phenomenon in which the difference in the reproduction signal amplitude occurs due to the difference in the pits occurs because the pits recorded become tear-shaped as the value of PH2 increases, and the tear-shaped becomes more prominent as the recording pits become longer. Is.

That is, when the value of PH2 is optimum,
As shown in FIG. 10A, the 6T and 8T recording pits are ideal recording pits, and the reproduction signal amplitudes of the 6T pit and the 8T pit are equal. However, when the value of PH2 becomes larger than the optimum value, the recording pits of 6T and 8T become teardrop-shaped as shown in FIG. 10B, and a difference occurs in the reproduction signal amplitude of 6T and 8T. Therefore, the value of PH2 at which the difference between the reproduction signal amplitudes starts to be the optimum value, and the optimum value of PH2 is determined by finding this value. In this way, the optimum value of PH2 is obtained, after which S in FIG.
PH obtained earlier by performing processing after 20
The ratio with 1 '(β = PH2' / PH1 ') is obtained, and by further performing the processing of FIG. 5, PL, PH1, PH2
The value of is determined.

Also in the present embodiment, in the case of the CAV method, the write test is performed at the recording radius positions such as the inner circumference, the middle circumference, and the outer circumference of the disk as described above, and PL1 and PH1 obtained at each position are tested. , PH2 are stored in the memory, and the optimum recording power is set according to the radial position based on the stored values.

Further, in the above embodiment, the laser lighting waveform is the lighting waveform as shown in FIG. 2, but the present invention is not limited to this, and for example, FIG. 11 (a), FIG.
The lighting waveform may be as shown in (b) or FIG. 11 (c). 11A to 11C show laser lighting waveforms when a 4T pattern is recorded as in FIG.

Further, the present invention can be applied to a case where a low temperature level state is created by pulse lighting. FIG. 12A is a recording pattern, FIG.
(C) is a diagram showing a corresponding laser lighting waveform. FIG. 12B shows a low temperature level state (space) at DC.
FIG. 12C shows a laser lighting waveform in the case of forming by lighting, and a laser lighting waveform in the case of forming a low temperature level state by pulse lighting. In the above embodiment, FIG.
Although the space is DC-lit as shown in (b), the present invention can be applied to the case where the space is pulse-lit as shown in FIG. 12 (c). However, a point to be noted in this case is that when the PL level is determined as PL = α ′ × PHth from the value of PHth at which the high temperature process starts, the setting of α ′ is different from that of the embodiment. '> 1.0
Is to be. When the low temperature level state is generated by pulse lighting as described above, there is an advantage that the accuracy of the laser power control at the low temperature level can be improved.

Further, in the embodiment, as a method for obtaining PHth immediately before the start of the high temperature process, an 8T continuous pattern is recorded and the recording power at which the reproduction signal amplitude rises is set to P.
I explained that it is calculated as Hth, but the test pattern 8T
The mark portion of the continuous signal may be illuminated with a pulse having a length of 1 / 2T. In this case, P obtained from the value of PHth
The level of L is PL = γ × PHth, and the coefficient γ at this time is γ <1.0.

Further, in the embodiment, PL, PH1, PH
The write test has been described as an example in the case of the four-value control in which the four-value control of 2 and Pr is performed.
It can also be applied to the case of value control. In the case of this three-value control, the write test is performed as follows. First, FIG.
From S1 to S8 of 4 is the same as the case of four-value control, PHth
Is detected and PL is set based on it. Next, in the case of ternary control, since the power level forming the high temperature level state (recording) is only PH, PH = P in S9 of FIG.
Hth, and 8T continuous and 2T continuous patterns are recorded at the power level of PH in S10.

Then, in S11, the 8T and 2T continuous patterns are reproduced to detect the slice levels of the reproduced signals of 8T and 2T, and in S12, the difference ΔSL between the slice levels of 8T and 2T.
Is detected and whether or not ΔSL is 0 is determined in S13. If ΔSL is not 0, ΔPH is added to PH in S14 to update the recording power, recording of 8T and 2T continuous patterns again, detection of the slice level of the reproduced signal, detection of the difference ΔSL, and ΔSL being 0. Is determined. In this way, the processes of S10 to S14 are repeated, and the value of PH when ΔSL becomes 0 is determined as the optimum power level. With the above, the optimum values of PL and PH are obtained, and the write test in the case of three-value control is completed. As described above, the present invention can be applied to the write test in the case of three-value control.

[0042]

As described above, according to the present invention, the power level for detecting the power level immediately before the start of the high temperature level state and forming the low temperature level state based on the detected power level, and the high temperature level By determining the power level for forming the level state, it is possible to set the recording power to the optimum power level according to the temperature change in the device, and it is not affected by temperature change or dirt on the objective lens, medium, etc. The recording pits can be stably recorded, and there is an effect that high speed and high density information recording can be supported.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an optical information recording / reproducing apparatus of the present invention.

FIG. 2 is a diagram showing a laser lighting waveform when recording the 4T pattern of the embodiment of FIG.

FIG. 3 is a flowchart showing an embodiment of a write test method of the present invention.

FIG. 4 is a flowchart showing an embodiment of the write test method of the present invention.

FIG. 5 is a flowchart showing an embodiment of the write test method of the present invention.

FIG. 6 shows the laser power P immediately before the start of the high temperature level state.
It is a figure for demonstrating the method of calculating Hth.

FIG. 7: 8T continuous used in the light test of the present invention,
It is a figure showing a reproduced signal of a 2T continuous pattern.

FIG. 8 is a diagram showing the relationship between the radial position (linear velocity) of the disc and the recording power.

FIG. 9 is a diagram for explaining another method of obtaining PH2 for forming a high temperature level state.

FIG. 10 is a diagram for explaining the principle of obtaining PH in FIG. 9;

FIG. 11 is a diagram showing another example of a laser lighting waveform of a 4T pattern.

FIG. 12 is a diagram showing a recording pattern and a laser control signal corresponding thereto in comparison between a case where a space is DC-lit and a case where a space is pulse-lit.

FIG. 13 is a diagram showing a conventional magneto-optical disk device.

[Explanation of symbols]

 1 Magneto-optical disk 3 Spindle motor 4 Optical head 5 Semiconductor laser 8 Objective lens 11, 16 Optical sensor 12 AT / AF circuit 13 Bias magnet 14 Objective lens actuator 17 Amplitude detection circuit 18 CPU 19 Acimentary detection circuit 20 Semiconductor laser drive circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Miyashita 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (5)

[Claims] 1. A predetermined signal is recorded by changing a recording power in a write test area of an information recording medium, and a power level immediately before a high temperature level state of the recording medium starts is detected based on an amplitude of a reproduced signal, A light test method, comprising: determining a power level for forming a low temperature level state and a power level for forming a high temperature level state, based on a detected power level immediately before a high temperature level state starts. 2. The write test method according to claim 1, wherein the power level for forming the low temperature level state is determined by multiplying a power level immediately before the high temperature level state starts by a predetermined coefficient. A light test method characterized in that 3. The write test method according to claim 1, wherein the power level for forming the high temperature level state is a recording medium in which the recording power is changed based on the power level immediately before the high temperature level state starts. Signals of different lengths are recorded in the write test area, and each time the signals are recorded, the signals of different lengths are reproduced to detect the difference between the peak value and the bottom value of the two reproduced signals having different lengths. Then, the light test method is characterized by making a decision based on the difference between the detected intermediate values. 4. The write test method according to claim 1, wherein the recording power is changed to record signals of different lengths in a write test area of a recording medium, and the peaks of reproduced signals of two signals of different lengths are recorded. The two power levels for forming the high temperature level state are detected based on the difference between the intermediate value and the bottom value, the ratio of the two power levels for forming the high temperature level state is calculated, and this ratio is kept constant. The signals with different lengths are recorded in the write test area while the recording power is kept constant, and the high temperature level is determined based on the difference between the peak value and the bottom value of the reproduction signals of the two signals with different lengths. A write test method characterized by determining absolute values of two power levels for forming a state. 5. An optical information recording / reproducing apparatus for recording information by controlling a recording power of a light beam on an optical information recording medium by multilevel control, and recording a predetermined signal in a write test area of the recording medium. Means for detecting the reproduction signal amplitude of the recorded signal, means for detecting the power level immediately before the high temperature level state of the recording medium starts based on the reproduction signal amplitude, and detection The power level for forming the low temperature level state based on the power level immediately before the start of the high temperature level state,
And a means for determining a power level for forming a high temperature level state, an optical information recording / reproducing apparatus.