JPH0792923B2 - Optical disk device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device for recording / reproducing information by irradiating a rotationally driven optical disk with a laser beam from a reciprocally driven pickup.

<Prior Art> Conventionally, for example, in an optical disc device using a magneto-optical disc as a recording medium, a weak magnetic field is applied to the perpendicular magnetization film of the magneto-optical disc in the direction of magnetization reversal, and a laser spot is irradiated to form the perpendicular magnetization film. While partially heating above the Curie point and reversing the magnetic field of that part to record pits, pits are irradiated with a laser beam and the rotation of the polarization plane of the reflected or transmitted light is detected to reproduce. I am doing it. Then, as shown in FIG. 7, the information is recorded by modulating digital information of "1" and "0" into a laser driving pulse to turn on / off the laser, and recording at a certain value Po or more required for recording. This is performed by irradiating a disk rotating at a constant speed with a laser beam having a time setting power, and a recording pulse having a pulse length tw is recorded. However, since the recording method is heating of the disk as described above, it is necessary to accurately control the on-time and power of the laser in order to obtain the same recording state. Therefore, the conventional optical disk device is provided with an adjusting knob for initially setting the power of the recording laser light and the recording pulse length according to the ambient temperature which affects the recording quality.

<Problems to be Solved by the Invention> However, the parameters that affect the recording quality of the conventional optical disc device include the ambient temperature and the change in the recording sensitivity of the optical disc due to the temperature rise in the device after the power is turned on. Since there are various things such as changes in the laser optical system over time, variations in recording sensitivity between optical disks, and peripheral speed differences between the inner and outer circumferences of the disk in the case of the disk constant speed rotation method, only the initial adjustment of the recording conditions described above In reality, it is difficult to stably record the same recording data having desired reliability on an optical disc. Therefore, there are problems that the adjustment of the device becomes complicated, the data compatibility between the optical discs of the device is impaired, and the reliability of the device decreases.

Therefore, an object of the present invention is to have a self-diagnosis function capable of appropriately controlling the power of a recording laser beam and a recording pulse length to an optimum value in accordance with variations in various parameters that affect the recording quality of an optical disc. Another object of the present invention is to provide an optical disk device capable of stably recording high-quality data with high reliability.

<Means for Solving Problems> In order to achieve the above object, the optical disk device of the present invention is
A pickup driving unit that drives a pickup that performs recording and reproduction on an optical disc by a laser beam in a radial direction of the optical disc, and an ambient temperature and an output value of a laser beam that can perform optimum recording at the ambient temperature are stored in association with each other. A recording power reference table, a recording pulse length reference table that stores the pickup position in the radial direction of the disk in association with the pulse length of the laser light that allows optimum recording at that pickup position, and the temperature sensor detects during test erasing Recording power deviation detection that finds and holds the optimum value of the recording laser light output based on the ambient temperature and the above recording power reference table, and detects and holds the deviation between this optimum value and the recording laser light output value measured by itself during the test erasure. The holding circuit, the recording pulse length for the optical disc and the reproduction pulse length It has a corresponding reference table, finds the deviation of the pulse length of the reproduction pulse that is simultaneously reproduced at the time of test recording from the recording pulse length, and finds the correction value representing the increment of the recording pulse length that cancels this deviation from the above-mentioned reference table. And a recording pulse length correction value setting circuit for holding the output of the recording laser light during normal recording, the output value of the recording laser light measured during the test erasing and the deviation held in the recording power deviation detection holding circuit. The curve represented by the recording pulse length reference table is controlled so as to be the sum, and the curve is translated in such a manner that the recording pulse length is lengthened by the correction value at the disc radial position of the pickup during the test recording. Control the pulse length of the recording laser light according to the disc radial position of the pickup based on the new reference table Characterized by comprising the Za driving circuit.

<Operation> Prior to normal recording / reproducing, when the test erasing process is started, the pickup driving section drives the pickup to a predetermined radial position of the rotating disk, and the laser driving circuit picks it up to a predetermined position. The output recording laser beam is emitted toward the disc. Then, the recording power deviation detection holding circuit refers to the recording power reference table that stores the ambient temperature and the output value of the laser beam that can perform optimum recording at the ambient temperature in association with each other, and at this time, the temperature sensor detects the temperature. Obtain the optimum value of the recording laser light output corresponding to the ambient temperature, detect the deviation between this optimum value and the output value of the recording laser light measured by itself at this time, and measure the deviation Hold with output value of.

Then, when the test recording process is started, the laser drive circuit outputs an output equal to the sum of the held deviation and the measured output value of the recording laser beam at the same radial position as that at the time of test erasing, and the disc radius. Direction pickup position and the recording pulse length reference table that stores the pulse length of the laser beam that can perform optimum recording at that pickup position in correspondence with the recording pulse length obtained for the above-mentioned radial position. And emits a laser beam. Then, the recording pulse length correction value setting circuit obtains a deviation of the pulse length of the reproduction pulse reproduced at this time from the recording pulse length, and a correction value representing an increment of the recording pulse length for canceling the deviation is given to the optical disc. The correction value is held by obtaining it from the reference table in which the recording pulse length and the reproduction pulse length are associated with each other.

After that, when normal recording starts, the laser drive circuit
The output of the recording laser light is controlled to be the sum of the output value of the recording laser light measured at the time of the test erasure and the held deviation, and the pulse length of the recording laser light is set to the recording pulse length reference. The curve represented by the table is moved parallel to the pickup disk radial position during the test recording so that the recording pulse length is increased by the above-mentioned correction value. Control.
Thus, the normal recording / reproducing process is performed under the optimum conditions by the test erasing and the test recording process in advance.

If the test erasure and test recording are performed at regular intervals even during power-on of a device with large fluctuations in ambient temperature, when exchanging discs with different recording sensitivities, and during normal recording, the recording conditions will be changed each time. It can be modified to the optimum value.

Furthermore, if the test erasing and the test recording are performed on a track other than the user area on the optical disk, it is possible to record / reproduce under the optimum condition without destroying the information recorded in the user area.

<Examples> Hereinafter, the present invention will be described in detail with reference to illustrated examples.

FIG. 1 is a block diagram showing an embodiment of the optical disk device of the present invention. Reference numeral 1 is a magneto-optical disk which is held by a spindle motor 2 and is rotationally driven, and 3 is a built-in condenser optical system for recording and erasing. A pickup for emitting a laser beam 4 for reproduction, a linear motor for driving the pickup in the disk radial direction, a control circuit 6 for controlling the operation of each block of the apparatus, and a reference numeral 7 for output from the control circuit 6. A modulation circuit that modulates a recording data string into a laser on / off signal, and 8 stores a comparison table (see FIG. 6) between the disk radial position and the optimum recording pulse length, and modulates based on a command from the control circuit 6 described above. A recording pulse length reference table for adjusting the ON / OFF signal from the circuit 7 to an optimum pulse length corresponding to the disk radial position, and 9 is an output from the recording pulse length reference table 8. No. was amplified to a predetermined power, a laser drive circuit for irradiating a laser beam 4 through the pickup.

Reference numeral 10 stores a comparison table (see FIG. 3) between the ambient temperature and the optimum recording laser light power, and is equipped with a temperature sensor. The optimum recording laser light determined by the comparison table from the ambient temperature measured by this temperature sensor. A deviation between the power and the power of the recording laser light obtained from the reflected light amount signal of the recording laser light input from the pickup 3 is detected, and the power of the recording laser light is corrected based on the above comparison table so as to eliminate this deviation. A recording power deviation detection circuit 11 for holding the power value of the recording laser beam corrected by the recording power deviation detection circuit 10 and setting it as a power value to be amplified in the laser drive circuit 9 , 12 is a reproducing circuit for reproducing the signal read through the pickup 3, and 13 is an output from this reproducing circuit. This is a reproduction pulse length detection circuit that detects the pulse length of the reproduction pulse and inputs it to the control circuit 6.
The recording power deviation detection circuit 10 and the recording power setting holding circuit 11 constitute a recording power deviation detection holding circuit.

Further, reference numeral 14 holds a recording pulse length correction value determined so as to eliminate the deviation between the pulse length of the recording pulse and the pulse length of the reproducing pulse stored in advance by the control circuit 6 at the time of recording. A recording pulse length correction value setting circuit for correcting the recording pulse length reference table 8, 15 is the reproducing circuit 12
A demodulation circuit that demodulates the signal from the device, 16 is a detection circuit that detects power-on and optical disk replacement, which are conditions for automatically adjusting the recording laser light power and the recording pulse length to the optimum values, and 17 is used during normal use A timer that measures the time for entering the automatic adjustment process at regular intervals, 18 receives the signals from the detection circuit 16 and the timer 17, and the automatic adjustment process start command signal output from the control circuit 6 causes the laser It is a test erase instruction circuit for operating the drive circuit 9, the recording power deviation detection circuit 10, and the recording power setting holding circuit 11.

Of the lines connecting the blocks in FIG. 1, the broken line shows the signal flow for setting the optimum recording laser light power in the automatic adjustment process, and the solid line shows the signal flow for setting the optimum recording pulse length in the automatic adjustment process. Flows, a solid line and a double solid line, respectively, show signal flows in normal processing.

That is, when the start of the automatic adjustment processing is instructed from the control circuit 6 as shown by the broken line, the pickup 3 causes the linear motor 5 controlled by the control circuit 6 to move the predetermined automatic adjustment processing track 1a of the magneto-optical disk 1 to the pickup 3. (See FIG. 5), first the test erase (test erase) mode is entered, the laser light 4 is emitted from the pickup 3 with the recording laser light power previously held in the recording power setting / holding circuit 11, and recording is performed. The power deviation detection circuit 10 detects a deviation between the power of the laser light and the optimum recording laser light power at the ambient temperature, corrects the power of the recording laser light to eliminate this deviation, and corrects the power value. Is held in the recording power setting holding circuit 11, the recording power setting holding circuit 11 resets the power value in the laser drive circuit 9, and then the The strays instruction circuit 18 is turned off to finish setting the optimum recording laser light power. Next, a test write (test recording) mode shown by a solid line is entered, and the signal is output from the control circuit 6 through the modulation circuit 7, the recording pulse length reference table 8 and the laser drive circuit 9 and corresponds to the disk radial position of the track 1a. Laser light 4 is emitted by a driving current having an optimum recording pulse length, and recording is performed on the magneto-optical disk 1. afterwards,
The reproduction circuit 12 reproduces this recorded data read by the pickup 3, the reproduction pulse length detection circuit 13 detects the pulse length of the reproduction pulse and inputs it to the control circuit 6, and the control circuit 6
A recording pulse length correction value is calculated so as to eliminate the deviation between the optimum recording pulse length and the pulse length of the reproduction pulse, and this is output to the recording pulse length correction value setting circuit 14. Then, the recording pulse length correction value setting circuit 14 corrects the recording pulse length reference table 8 with the above correction value, completes the setting of the optimum recording pulse length, and returns to the normal mode. In the normal mode, recording / reproduction is performed with the optimum recording laser light power and the optimum recording pulse length thus set.

The automatic adjustment process of the optical disc device having the above configuration will be described below with reference to the second flowchart.

Steps S1, S2, S3 Normal processing flow of optical disk device
In F0, when the detection circuit 16 detects the power-on or the exchange of the optical disk, or the timer 17 measures a certain time, the control circuit 6 determines the optimum recording laser light power setting flow F1 by test erase and the optimum write laser light power setting by test write. The automatic adjustment process consisting of the recording pulse length setting flow F2 is started.

Step S4 The control circuit 6 drives the linear motor 5 to move the pickup 3 to the track 1a outside the user area 1b shown in FIG. 5 on the magneto-optical disk 1, and applies a predetermined erasing power to the track 1a. Erase with the laser beam 4. The erasing power is set by the recording power deviation detecting circuit 10 as shown in FIG. That is, when the ambient temperature measured by the built-in temperature sensor is To ° C., the recording power deviation detection circuit 10 obtains the optimum recording laser light power Po corresponding to this temperature by the stored comparison table and gives this power value Po. The laser drive circuit 9 is adjusted so as to output such a drive current.

Step S5 Laser light 4 emitted with erase power Po
Is the power deviation detection circuit 10 via the pickup 3.
If the measured power at that time is P'lower than the optimum value Po as shown in FIG. 3, the power deviation detection circuit 10 changes the laser drive current so as to eliminate the deviation ΔPo between Po and P '. to correct. Then, the corrected drive current value is held in the recording power setting holding circuit 11 and set in the laser drive circuit 9, so that the power of the laser light becomes the optimum value Po. Further, as shown in FIG. 3, when the ambient temperature is T ° C. and the measured power is P ″ higher than the optimum value P (T ° C.), the same correction is performed so as to eliminate the deviation ΔP _T. The setting of the optimum recording laser light power Pw is completed in step S6.

Step S7 Next, the control circuit 6 uses the laser beam 4 having the set optimum recording laser beam power for the track 1a.
Record. In this recording, the digital information as shown in FIG. 4 (a) output from the control circuit 6 is passed through the modulation circuit 7 and the recording pulse length reference table 8 to obtain the optimum pulse length tw corresponding to the disk radial position of the track 1a. The pulse train is modulated, and this pulse train is amplified by the laser drive circuit 9 to the power Pw.

In step S8, the data recorded on the track 1a in this manner is reproduced by the reproducing circuit 12 and the reproduction pulse length is
t _R becomes shorter than the reference value of the reproduction pulse length by Δt _R as shown by the broken line in FIG. 4A due to the deviation of the recording sensitivity of the disc.

Step S9 The deviation Δt _R is detected by the reproduction pulse length detection circuit 13 and input to the control circuit 6, and the control circuit 6 corrects the value of the recording pulse length tw so as to eliminate the deviation Δt _R. That is, in order to lengthen the reproduction pulse length t _R by Δt _R , as shown in FIG. 4 (c), the recording pulse length is made longer than tw by Δtw to be tw _0, and this Δtw is set to the recording pulse length correction value setting value. Output to the circuit 14 and hold.

Step S10 The recording pulse length reference table 8 for storing the reference curve of the disc radial position and the optimum recording pulse length as shown by the broken line in FIG. 6 is the correction in the track 1a output from the recording pulse length correction value setting circuit 14. Based on the amount Δtw, the reference curve is translated upward by Δtw as shown by the solid line, and the setting of the optimum recording pulse length is completed. In this way, the pulse length of the recording pulse passing through the recording pulse reference table 8 is corrected to tw ₀ as shown in FIG. 4B, and the pulse length of the reproduction pulse is corrected to the reference value t _R0 . The optimum recording laser light power Pw and the optimum recording pulse length tw ₀ set as described above are retained until the next automatic adjustment processing of the recording conditions is performed, and in the subsequent normal processing flow F 0, the magneto-optical disk 1 is stored. Used when recording information in the user area 1b.

In the above embodiment, the ambient temperature for the optimum recording laser light power and the disk radial position for the optimum recording pulse length, which have the greatest influence, are selected from various parameters that affect the recording quality of the optical disk, and these two stored reference curves are stored. On the basis of the above, the deviation from the optimum value is corrected including the influence of other parameters such as the change with time of the laser and the variation of the sensitivity of the optical disk, so that there is an advantage that the correction can be performed easily and accurately. In addition, this correction, that is, the automatic adjustment processing is performed at a predetermined time interval by the timer 17 not only when the power of an apparatus with large fluctuations in ambient temperature is turned on, when a disc whose recording sensitivity changes, but also during normal use. Can be corrected to the optimum value each time. Furthermore, since the automatic adjustment processing is performed on the dedicated track 1a of the optical disc 1, there is no risk of destroying the information recorded in the user area 1b. Therefore, the information recorded under such optimum conditions makes it possible to accurately and easily discriminate the information at the time of reproduction, simplify the initial adjustment of the apparatus, and greatly improve the data reliability.

It should be noted that the recording condition correction in the normal use by the timer 17 in the above embodiment is not necessarily required to be performed every fixed time, and the recording condition correction may be performed in addition to the power-on and the disc exchange.

<Effects of the Invention> As is clear from the above description, the optical disk device of the present invention is a recording power reference table that stores the optimum output value of the recording laser beam with respect to the ambient temperature that affects recording quality, and recording with respect to track positions. Equipped with a recording pulse length reference table that stores the optimum value of the pulse length as a curve, the output of the recording laser light is corrected to the optimum value corresponding to the ambient temperature during test erasing, and it is held in the recording power deviation detection holding circuit for test recording. Sometimes, the deviation of the pulse length of the reproduction pulse that is reproduced at the same time is found with respect to the recording pulse, and the increment of the recording pulse length that cancels this deviation is found from the reference table and held as a correction value in the recording pulse length correction value setting circuit, and normal recording At the same time, the laser drive circuit controls the output value of the recording laser light to the above-mentioned optimum value held, and Is moved in parallel at the track position during the test recording by the held correction value, and the pulse length of the recording laser light is controlled according to the track position based on the parallel-moved curve. The recording laser light output and recording pulse length are appropriately set to optimum values according to the fluctuations in the optical disk position and the disk radial position of the pickup to stably record high-reliability and high-quality data on the optical disk. This makes it possible to accurately and easily discriminate information during playback as well as simplify initial adjustment, which greatly contributes to the improvement of device data compatibility and reliability.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the optical disk device of the present invention, FIG. 2 is a flow chart showing the automatic adjustment processing of the optical disk device, and FIG. 3 is a reference curve of ambient temperature and optimum recording laser light power. FIG. 4 is a diagram showing the relationship between the recording pulse length and the reproducing pulse length, FIG. 5 is a plan view of the optical disc, FIG. 6 is a diagram showing a reference curve of the disc radial position and the optimum recording pulse length, and FIG. FIG. 6 is a diagram showing a conventional recording method using laser light. 1 ... Magneto-optical disk, 3 ... Pickup, 4 ... Laser light, 5 ... Linear motor, 6 ... Control circuit, 7 ... Modulation circuit, 8 ... Recording pulse length reference table, 9 ... Laser drive Circuit, 10 ... Recording power deviation detection circuit, 11 ... Recording power setting holding circuit, 12 ... Reproducing circuit, 13 ...
… Playback pulse length detection circuit, 14 …… Recording pulse length correction value setting circuit, 16 …… Detection circuit,
17 …… Timer, 18 …… Test erase instruction circuit.

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Kunio Kojima 22-22 Nagaike-cho, Abeno-ku, Osaka, Osaka Incorporated (72) Inventor Takeshi Yamaguchi 22-22, Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (56) Reference JP 58-80138 (JP, A) JP 59-24452 (JP) , A)

Claims (3)

[Claims] 1. A pickup driving unit for driving a pickup for recording and reproducing on an optical disc by a laser beam in a radial direction of the optical disc, an ambient temperature and an output value of the laser beam capable of optimum recording at the ambient temperature. A recording power reference table that is stored in association with each other, a recording pulse length reference table that stores the pickup position in the radial direction of the disc and the pulse length of the laser light that enables optimum recording at that pickup position, and a test erase time The optimum value of the recording laser light output is found from the ambient temperature detected by the temperature sensor and the recording power reference table, and the deviation between this optimum value and the recording laser light output value measured by itself during the test erasure is detected and held. Recording power deviation detection and holding circuit, and recording pulse length for the optical disc and its It has a reference table in which reproduction pulse lengths are associated with each other, finds the deviation of the reproduction pulse pulse reproduced at the time of test recording from the recording pulse length, and sets a correction value representing the increment of the recording pulse length to cancel this deviation. The recording pulse length correction value setting circuit which is obtained from the comparison table and holds it, and the output of the recording laser light during normal recording is held in the output value of the recording laser light measured during the test erase and the recording power deviation detection holding circuit. Control is performed so that it becomes the sum of the deviations, and the curve represented by the recording pulse length reference table is moved in parallel so that the recording pulse length becomes longer by the correction value at the disk radial position of the pickup during the test recording. Based on the new reference table that represents the curved line, the recording laser beam pulse An optical disc device comprising a laser drive circuit for controlling the optical disc length. 2. The optical disk device according to claim 1, wherein the test erasing and test recording are performed at a constant time when the device is powered on, when the optical disk is replaced, and when normal recording is performed. An optical disk device characterized in that 3. The optical disk device according to claim 1 or 2, wherein when the test erasing and the test recording are performed, the laser light is emitted by the pickup driving section to a portion other than a user area of the optical disk. An optical disk device characterized by being adapted to irradiate a track.