JP3958766B2 - Optical storage - Google Patents

Description

  The present invention relates to a reproducing laser power setting method for setting a reproducing laser power when information is recorded and reproduced using a laser beam.

In recent years, optical disks have attracted attention as external recording media for computers. Optical discs use a laser beam to create magnetic recording pits on the order of submicrons, greatly increasing the recording capacity compared to conventional external recording media such as floppy disks and hard disks. It becomes possible to make it. Furthermore, information can be rewritten in a magneto-optical disk, which is a perpendicular magnetic recording medium using a rare earth-transition metal material, and future development is expected more and more.

  The optical disc has a storage capacity of about 128 MB on one side of, for example, 3.5 inches. This is the storage capacity when a track having a pitch of 1.6 μm is provided on a disk radius of 24 mm to 40 mm and a pit having a minimum of about 0.75 μm is recorded in the circumferential direction for a 3.5-inch optical disk.

  This means that one 3.5-inch floppy (R) disk has a storage capacity of about 1 MB, and one optical disk has a storage capacity of 128 floppy (R) disks. As described above, the optical disc is a rewritable recording medium having a very high recording density.

  However, in preparation for the future multimedia era, it is necessary to further increase the recording density of the optical disk. In order to increase the recording density, more pits must be recorded on the medium. To that end, it is necessary to make the pits smaller than the present and to narrow the interval between pits.

  When the recording density is increased by such a method, it is necessary to make the wavelength of the laser light shorter than the current 780 nm. However, in consideration of practical use, the pit size must be reduced at the current wavelength 780 nm. . In this case, for recording, it is possible to form pits smaller than the beam diameter by controlling the power of the laser beam. However, with regard to playback, if a pit smaller than the beam diameter is played, crosstalk with the adjacent pit increases, and in the worst case, the adjacent pit enters the playback beam, and practicality is considered. ,very difficult.

  As a method for reproducing a bit smaller than the beam diameter at the current wavelength of 780 nm, there is a magneto-optical recording / reproducing method disclosed in Japanese Patent Laid-Open No. 3-93058, and a recording / reproducing method using super-resolution technology (MSR: Mag-netically induced Super Resolution). Are known. As shown in FIGS. 10A and 10B, the recording medium is divided into a recording layer 120 and a reproducing layer 116, and recording is performed by applying a recording magnetic field Hr while irradiating a laser spot 122 of a light beam.

  At this time, depending on the temperature distribution of the medium heating by the laser spot 122, the switch layer 118 formed at the boundary with the recording layer 120 is magnetically coupled to the opening 124 with respect to the recording layer pit 128 of the reproducing layer 116. It becomes. On the other hand, in the next recording pit 130 portion, the magnetic coupling of the switch layer 118 is released and a mask portion 126 is formed. For this reason, perpendicular magnetization by the recording magnetic field Hr can be written to the recording pits 128 of the recording layer 128 without applying the recording magnetic field Hr to the adjacent pits 130.

  For reproduction after recording, as shown in FIGS. 11A and 11B, initialization is performed so that the magnetization direction of the reproduction layer 116 is made constant by using an initialization magnet 132, and the reproduction laser power during reproduction is slightly increased. Then, the laser spot 134 of the lead beam is irradiated. At this time, depending on the temperature distribution of the medium heating by the laser spot 134, the reproducing layer 116 has the mask portion 136 where the initial magnetization information remains and the opening portion where the initial magnetization information is erased and the magnetization information of the recording layer 126 is transferred. 138 is formed.

  The magnetization information of the recording layer 120 transferred to the reproducing layer 116 is converted into an optical signal by an optical magnetic effect (Kerr effect or Faraday effect), thereby reproducing data. At this time, since the pit 142 of the recording layer 120 to be read next is not transferred by the formation of the mask portion 136 based on the initial magnetization information of the reproducing layer 116, the recording pit is not a laser spot. Even if it is smaller than 134, crosstalk does not occur and pits smaller than the beam diameter can be reproduced.

Furthermore, when this super-resolution technique is used, the area of the recording layer 120 other than the reproduction portion is masked by the initialized reproduction layer 116, so that no pit interference from the adjacent pit occurs. Furthermore, the pit interval can be further reduced, and crosstalk from adjacent tracks can be suppressed, so that the track pitch can also be reduced, and the density can be increased even using the current wavelength of 780 nm. It becomes.
Japanese Unexamined Patent Publication No. 7-029238 JP-A-4-205823

  However, the conventional optical disk apparatus using such a super-resolution technique has a problem that an appropriate reproducing operation cannot be performed unless the reproducing laser power used at the time of reproduction is strictly controlled.

  The reason is that if the reproduction laser power is too low, transfer from the recording layer to the reproduction layer does not occur, and data that should have been recorded cannot be read out. Conversely, if the reproducing laser power is too high, there is a possibility that the data in the recording layer is destroyed.

  For this phenomenon, it is not sufficient to adjust the reproduction laser power, and it greatly depends on the environmental temperature inside the apparatus that determines the temperature of the recording medium. That is, when the environmental temperature in the apparatus changes to the low temperature side, transfer from the recording layer to the reproduction layer does not occur sufficiently, and the level of the reproduction signal decreases and the error rate increases. On the contrary, if the environmental temperature in the apparatus changes to a high temperature side, the data in the recording layer may be destroyed.

The present invention has been made in view of such conventional problems, and sets the reproduction laser power used when reproducing the data of the magneto-optical recording medium using the super-resolution technique to the optimum value by the calibration operation. In addition, an object of the present invention is to provide a reproducing laser power setting method and an optical storage device that minimize the time during which the use of the apparatus is interrupted by a calibration operation.

  FIG. 1 is a diagram illustrating the principle of the present invention.

  First, the optical disk apparatus of the present invention uses a reproducing laser power when using an optical recording medium having at least a recording layer for recording data on a substrate and a reproducing layer for reproducing data recorded on the recording layer. The reproduction method for determining the optimum value of the reproduction laser power by performing the reproduction operation of the optical recording medium after the first set time set in the first timer means has elapsed from the power-on or reset start. Perform laser power calibration processing, perform reproduction laser power calibration processing every time the first set time by the first timer means elapses until the second set time set by the second timer means elapses from power-on, After the second set time by the second timer means has elapsed and when the first set time by the first timer means has elapsed, In addition to pausing the raw laser power calibration process, the temperature difference between the detected operating temperature of the device detected this time and the previous detected operating temperature is checked, and if the temperature difference exceeds a predetermined value, the reproduction laser power calibration process is performed and optical recording is performed. When the medium is loaded, the reproduction laser power is calibrated regardless of the timer conditions of the first timer means and the second timer means.

  In addition, the reproducing laser power is set when a magneto-optical recording medium having at least a recording layer for recording data and a reproducing layer for reproducing data recorded on the recording layer is used on a substrate. The laser power is set by performing a reproduction power calibration process that determines the optimum value of the reproduction laser power by performing the reproduction operation of the optical recording medium at regular time intervals. However, when the degree of change with respect to the previous temperature decreases, the reproduction laser power calibration process at certain time intervals is suspended until the temperature change exceeds a predetermined value.

  Also, a reproduction power calibration process is performed to determine the optimum value of the reproduction laser power by performing the reproduction operation of the optical recording medium at regular time intervals, and the optimum laser power value determined by the calibration of the reproduction laser power is the previous value. When the degree of change with respect to the value decreases, the reproduction laser power calibration process at the predetermined time interval is suspended.

  Also, a reproduction power calibration process is performed to determine the optimum value of the reproduction laser power by performing the reproduction operation of the optical recording medium at regular time intervals, and calibration is performed for interrupt requests from the host device during calibration of the reproduction laser power. It is determined whether to interrupt the interrupt request and continue the interrupt request.

  According to the present invention, recording is performed at a recording density smaller than the beam diameter (recording density higher than the cut-off spatial frequency), and used when reproducing data from a magneto-optical recording medium recorded at a recording density smaller than the beam diameter. The optimum reproducing laser power to be set is set to an optimum value obtained by the calibration process for actually performing the reproducing operation of the apparatus.

  For this reason, even if the environmental temperature in the optical disk device changes or a medium with different characteristics is inserted, data cannot be read due to insufficient power of the reproduction laser power, or the reproduction laser power is too strong for recording. It is possible to reliably prevent the data from being destroyed and always realize the optimum reproduction operation.

  Also, during the calibration operation, a value that eliminates the change in the reproduction signal is obtained while changing the reproduction laser power step by step from the minimum power, and a fixed value is added to this value to determine the optimum value, thereby making the calibration process more efficient. The time during which the use of the apparatus is interrupted by the calibration operation can be minimized.

  The present invention also provides an optical storage device for performing at least reproduction using an optical storage medium having at least a recording layer for recording data on a substrate and a reproduction layer for reproducing data stored in the recording layer. The reproduction power calibration processing means for determining the optimum value of the reproduction laser power by performing the reproduction operation of the optical storage medium at regular time intervals, and at the time of reproduction laser power calibration, the operating temperature of the apparatus is the previous temperature. When the degree of change is small, at least means for stopping the reproduction power calibration process at the predetermined time interval until the temperature change exceeds a predetermined value is provided.

  In the optical storage device of the present invention, reproduction power calibration processing means for determining the optimum value of the reproduction laser power by performing the reproduction operation of the optical recording medium at regular time intervals, and calibration of the reproduction laser power. And at least means for stopping the calibration process of the reproduction power at the predetermined time interval when the degree of change in the value of the optimum laser power determined by the above is less than the previous value.

  In the optical storage device of the present invention, the reproduction power calibration processing means for determining the optimum value of the reproduction laser power by performing the reproduction operation of the optical storage medium at regular time intervals, and the reproduction laser power And means for interrupting a calibration process in response to an interrupt request from a host device during calibration and determining whether to process the interrupt request.

Further, in the optical storage device of the present invention, the reproduction power calibration processing means for determining the optimum value of the reproduction laser power by performing the reproduction operation of the optical storage medium at regular time intervals, and during the calibration of the reproduction laser power And at least a mode setting unit for setting a mode for processing or continuing the interrupt request by interrupting the calibration process in response to the interrupt request from the host device, and the reproduction laser power calibration means includes: And processing for an interrupt request according to the set mode.

  As described above, according to the present invention, when the optical recording medium is inserted, every time the first set time elapses and until the second set time elapses, after the second set time elapses. Since the reproduction laser power calibration process is performed when the temperature inside the apparatus exceeds a predetermined value, the time during which the apparatus is interrupted by the calibration operation can be minimized.

  Prior to playback, the data recorded on the optical disk medium is played back by using the playback operation of the optical disk to determine the optimum playback laser power suitable for the ambient temperature in the device at that time and use it during playback. Reliable prevention of damage caused by laser light or inability to reproduce data due to insufficient reproduction laser power, greatly improving reliability when recording / reproducing with a recording density smaller than the beam spot diameter Can be improved.

  Also, with regard to the calibration process of the reproduction laser power, it is possible to obtain an envelope portion where the characteristic curve is saturated by changing the initial power step by step from the initial value, and adding a constant value to this to obtain the optimum reproduction laser power. Thus, efficient calibration processing can be performed in a short time by reducing processing steps.

  Furthermore, when a certain amount of time has elapsed since the start of use of the apparatus due to the introduction of the medium, the ambient temperature in the apparatus becomes saturated and stable, and in this state, the medium temperature hardly fluctuates, so the calibration of the reproduction laser power is suspended. Thus, it is possible to minimize the time during which the use of the apparatus is interrupted by the calibration operation, and extremely reduce the possibility that an access request from the host apparatus is awaited by the calibration operation.

In addition, by making it possible to determine whether or not to continue processing for an interrupt from a host device being calibrated, processing for an access request interrupt according to a set mode can be performed.

  FIG. 2 is a block diagram of the optical disk apparatus of the present invention. First, the optical disk apparatus of the present invention uses a magneto-optical recording medium having at least a recording layer for recording data and a reproducing layer for reproducing data recorded on the recording layer on a substrate. The recording unit records data on the recording layer of the magneto-optical recording medium with a recording density smaller than the beam diameter of the laser beam. The reproducing unit reproduces data recorded on the recording layer of the magneto-optical recording medium with a recording density smaller than the beam diameter by setting the reproducing laser power to an appropriate value. In addition to this, the present invention provides a reproduction laser power calibration unit to determine the optimum value of the reproduction laser power by performing the reproduction operation of the magneto-optical recording medium.

  In FIG. 2, the optical disc apparatus includes a controller 10 and an optical head unit 12. The optical head unit 12 is provided with a VCM 14 and moves and positions the optical head unit 12 in the radial direction of the optical disk. A lens actuator 16 is mounted on the optical head unit 12.

  The lens actuator 16 is also called a track actuator, and moves the objective lens that forms an image of the laser beam on the disk surface within a predetermined track range to control the beam position. In the seek operation, the optical head unit 12 is moved by the VCM 14 when the number of moving tracks is large, and the beam movement is performed by the lens actuator 16 when the number of moving cylinders is as small as 50 tracks, for example.

  The focus actuator 18 moves the objective lens provided in the optical head unit 12 in the optical axis direction, and adjusts the focus so that a prescribed beam spot is imaged on the disk medium surface. The photodetector 20 receives reflected light obtained by irradiating a laser beam onto the medium surface of the optical disc. For example, a four-divided photodetector is used as the photodetector 20, and a tracking error, a focus error, and a reproduction signal can be obtained by synthesizing the received light signals of the four light receiving units.

  The laser diode 22 generates a write beam during a write operation, a read beam during a read operation, and an erase beam during an erase operation. In the present invention, a laser diode having a wavelength of 780 nm is used. As the laser diode 22, one laser diode common to the write beam, the read beam, and the erase beam may be used, or the write beam and the erase beam are used as one laser diode, and another laser diode is used as the read beam. You may make it provide.

  The electromagnet 24 generates an external magnetic field for initialization during the erase operation. In addition, since the present invention uses an optical disc having at least a recording layer and a reproducing layer on a substrate according to the super-resolution technology as an optical disc, an electromagnet 24 is used as an initialization magnet when reproducing the optical disc. . The temperature sensor 26 detects the environmental temperature inside the apparatus.

  Here, although the optical head unit 12 is shown as one unit, it is actually divided into a movable unit that is moved in the radial direction of the optical disc and a fixed unit that is fixed to the apparatus housing. A lens actuator 16 and a focus actuator 18 are mounted on the movable part of the optical head 12, while a VCM 14, a photodetector 20, a laser diode 22, a temperature sensor 26, and an electromagnet 24 are installed on the fixed part side. As far as the movable side is lightened.

  The spindle motor 28 rotates the optical disk of the optical disk device. Since the optical disk apparatus of the present invention is intended for use of a 3.5 inch optical disk housed in a cartridge, the optical disk is chucked on the rotating shaft of the spindle motor 28 by loading the cartridge into the apparatus, and the chucking is completed. Thus, the spindle motor 28 is activated to rotate the optical disk at a constant speed.

  Next, the controller 10 side will be described. The controller 10 realizes the function by program control of a microprocessor (MPU) or a digital signal processor (DSP). The controller 10 is provided with an overall control unit 30 and exchanges commands, data, and the like from a higher-level optical disk control device via an interface control unit 32.

  When the overall control unit 30 receives an access request from a higher-level optical disk control device via the interface control unit 32 after completion of the initialization diagnosis operation at power-on, the overall control unit 30 performs a seek operation on the designated track address, The optical head unit 12 is on-tracked to the track to be controlled, and a write operation, a read operation or an erase operation is performed in this state.

  For the overall control unit 30, a position servo control unit 34, a focus servo unit 36, a light emission power control unit 38, a bias magnet control unit 40, and a motor control unit 42 are provided. The position servo control unit 34 detects a tracking error signal from the photodetector 20 in the tracking error detection circuit 44, takes it in by an AD converter 46, and performs a seek operation and on-track control after completion of the seek operation.

  The output of the position servo control unit 34 drives the VCM 14 via the DA converter 48 and the driver 50, and drives the lens actuator 16 via the DA converter 52 and the driver 54.

  The focus servo unit 36 takes in the focus error detection signal obtained by the focus error detection circuit 56 based on the detection signal of the photodetector 20 by the AD converter 58 and drives the focus actuator 18 via the DA converter 60 and the driver 62. Then, focus control is performed so that the laser beam has a prescribed spot diameter.

  The light emission power control unit 38 is connected to the laser diode via the laser drive circuit 64 so as to obtain a predetermined light emission power based on control instructions for the write operation, read operation, and erase operation by the overall control unit 30. 22 is controlled to output a laser beam having a prescribed emission power.

  The bias magnet control unit 40 drives the electromagnet 24 via the driver 70 during the erase operation or during initialization magnetization during reproduction. The motor control unit 42 receives the start command based on the completion of the insertion of the optical disk cartridge from the overall control unit 30 and rotates the spindle motor 28 at a constant speed via the driver 72.

  Further, a recording circuit 66 and a reproduction circuit 68 are provided outside the controller 10. The recording circuit 66 operates as a data modulation circuit, receives write data during a read operation by the overall control unit 30, generates a modulation signal, and supplies the modulation signal to the laser drive circuit 64 in accordance with the write data of the laser beam of the light beam. Modulation control. The reproduction circuit 68 functions as a data demodulation circuit, demodulates data from the reproduction light reception signal from the photodetector 20 of the optical head unit 12, and supplies it to the overall control unit 30.

  Further, in the present invention, the controller 10 is newly provided with a reproduction power calibration unit 74. The reproduction power calibration unit 74 performs a calibration operation for determining the optimum reproduction laser power to be used at the time of reproducing the optical disk based on an instruction from the overall control unit 30. The reproduction power calibration unit 74 receives the analog reproduction signal obtained by the reproduction circuit 68 and the temperature detection signal from the temperature sensor 26 after being converted into digital data by the AD converter 76.

  FIG. 3 is a functional block diagram of the reproduction power calibration unit 74 of FIG. In FIG. 3, the reproduction power calibration unit 74 is provided with an activation control unit 78, a calibration processing unit 84, a priority mode setting unit 86, and a reproduction laser power set value storage unit 88. A processing result based on the temperature detection signal from the temperature sensor 26 is given to the activation control unit 78 via the temperature processing unit 84.

  A first timer 80 and a second timer 82 are provided for the activation control unit 78. The first timer 80 is set with a time from the start of power-on of the apparatus until the internal environmental temperature is stabilized and the periodic calibration operation is not required. As the set time of the first timer 80, for example, a relatively long time such as 12 hours or 24 hours is set.

  The second timer 82 sets a certain time interval for performing the calibration operation after the power-on start of the apparatus. The set time of the second timer 82 is set to a short time for the first timer 80, for example, 1 hour.

  The activation control unit 78 is further provided with an initialization diagnosis instruction signal E1, a medium insertion detection signal E2, and an access request interrupt signal E3. The activation control unit 78 activates the calibration processing unit 84 at the timing when the initialization diagnosis instruction signal E1 is received in accordance with the power-on start of the apparatus, and activates the calibration process for determining the reproduction laser power.

  Thereafter, the calibration processing unit 84 is activated at a predetermined time interval set by the second timer 82, for example, once every hour, and the calibration operation is performed. When a time set by the first timer 80, for example, 12 hours elapses from the power-on start, the timer output of the first timer 80 is given to the activation control unit 78. The activation control unit 78 that has received the timer output of the first timer 80 does not perform the activation process of the calibration processing unit 85 even if it receives a subsequent timer output by the second timer 82. In this state, the temperature difference between the previous detected temperature and the current detected temperature by the temperature processing unit 84 is checked, and the calibration processing of the calibration processing unit 84 is started only when the temperature difference exceeds a predetermined value. .

  On the other hand, when the medium insertion detection signal E2 is received, the activation control unit 78 always activates the calibration processing unit 84 to obtain the reproduction laser power regardless of the timer conditions of the first timer 80 and the second timer 82. Perform calibration operation for

  Further, if there is an access request from the upper optical disk control device during the operation of the calibration processing unit 84, an access request interrupt signal E3 is given to the activation control unit 78. The calibration operation by the calibration processing unit 84 when receiving the access request interrupt signal E3 depends on the mode setting of the priority mode setting unit 86.

  The priority mode setting unit 86 interrupts the currently executed calibration process by interrupting the access request interrupt signal E3 from the host optical disk control device, or performs the access request interrupt process or without interrupting the calibration process. Any one of the modes to be continued is set, and the processing for the access request interrupt signal E3 according to the set mode is performed.

  The setting of the priority mode for the priority mode setting unit 86 can be performed by the operator using the panel or board of the apparatus, or the mode can be set by a command from the upper optical disk control apparatus side.

  FIG. 4 shows a recording layer and a reproducing layer on a substrate used in the present invention, and employs a super-resolution technique in which recording and reproduction are performed at a recording density smaller than the beam diameter of the laser beam, and at least recording is performed on the substrate. The reproduction signal output with respect to the reproduction laser power of an optical disc having a layer and a reproduction layer is expressed using temperature as a parameter.

  In FIG. 4, a characteristic curve 90 is when the environmental temperature is 0 ° C., a characteristic curve 92 is when the environmental temperature is 30 ° C., and a characteristic curve 94 is when the environmental temperature is 60 ° C. For example, when viewing the characteristic curve 92 at an ambient temperature of 30 ° C., a reproduction signal output is obtained from when the reproduction laser power becomes 1.5 mW, and when the reproduction laser power is increased, the reproduction signal output is almost linear. Increase.

  When the reproduction laser power reaches a point 98 at which 2.5 mW is reached, even if the reproduction laser power is increased further, the reproduction signal output is suppressed to, for example, 100 mV and becomes constant. The range of the characteristic curve 92 in which the reproduction signal output increases with respect to the increase in the reproduction laser power is that the reproduction laser power is too weak, and recording from the recording layer 120 to the reproduction layer 116 in the recording medium shown in FIG. Information is not sufficiently transferred, and the reproduction output signal is insufficient. This state is canceled when the reproducing laser power exceeding the point 98 is reached, and the transfer from the recording layer to the reproducing layer is efficiently performed.

  On the other hand, when the reproduction laser power is further increased, the reproduction signal output starts to decrease from around 4.0 mW, and the reproduction signal output cannot be obtained around 5.5 mW. This is a phenomenon that occurs when the reproduction laser power becomes too strong and the magnetization information of the recording layer is destroyed. Therefore, the optimum laser power at the time of reproduction in the characteristic curve 92 is desirably used in the range of 2.5 to 3.5 mW within which the reproduction curve output 100 mV at which the characteristic curve 92 is at a constant level.

  Such characteristics are basically the same for the characteristic curve 90 when the environmental temperature is 0 ° C. and the characteristic curve 94 when the environmental temperature is 60 ° C. That is, the characteristic curve shifts to the higher reproduction laser power side as the environmental temperature is lower, and a higher reproduction laser power is required because the environmental temperature is lower. On the other hand, when the environmental temperature rises, the characteristic curve shifts to the lower side of the reproduction laser power, and the medium temperature also rises due to the environmental temperature. Therefore, the laser power must be reduced.

  FIG. 5 shows the procedure of the calibration process by the reproduction power calibration unit 74 of the present invention in a state where the environmental temperature in the apparatus is 30 ° C. and the characteristic curve 92 of FIG. 4 is obtained. First, in the present invention, the minimum reproduction laser power W0 is set as an initial value. As the minimum reproduction laser power W0, for example, 1.0 mW which is a reproduction signal output start point when the ambient temperature is 60 ° C. in FIG. 4 is used.

  If the reproduction operation is started by setting the minimum reproduction laser power W0 = 1.0, then the reproduction laser power is increased step by step by a predetermined minute power ΔW. As this ΔW, a value of 0.5 mW, for example, ΔW = 0.25 mW is used. The reproduction signal output when ΔW = 0.25 mW is increased with respect to the minimum reproduction laser power W 0 becomes a point 103, and when it is further increased by 0.25 mW, a reproduction signal output starts to appear slightly at point 104. Further, when the reproduction laser power is increased to 2.0 mW by increasing 0.25 mW twice, the reproduction signal output at point 106 is obtained. Subsequently, when 0.25 mW is increased twice, point 108 is obtained. Furthermore, when it increases by 0.25 mW, it becomes point 110, but the reproduction signal output at point 110 does not increase with respect to the reproduction signal output at point 108 last time.

  Therefore, it is determined that the envelope portion of the characteristic curve has already passed, and the reproduction laser power W = 2.5 mW at the previous point 108 is obtained. When the reproduction laser power W at the envelope point 108 of the characteristic curve is obtained in this way, a predetermined fixed value Wc is added to this value to obtain the optimum reproduction laser power. A fixed value in the range of 0.5 mW to 2.5 mW is used as the fixed value Wc. In this embodiment, Wc = 1.0 mW is used.

  FIG. 6 shows the overall processing of the recording / reproducing operation in the optical disc apparatus of the present invention. First, in step S1, initialization and self-diagnosis are performed as the apparatus is powered on. During the self-diagnosis process, the reproduction laser power calibration process in step S2 is performed.

  When the reproduction laser power calibration process is completed, the first timer 80 and the second timer 82 are started in step S3, and an access request from the host optical disk control apparatus is waited in step S4. If there is an access request, the process proceeds to step S12, and a read operation, a write operation, or an erase operation is performed. If there is no access request, the process proceeds to step S5. For example, the output of the first timer that sets 12 hours is checked. Until the 12 hours elapse, the second timer that generates an output every hour in step S6. Check the output.

  At this time, if the output of the second timer set for one hour is obtained, the second timer is reset and started in step S7, and then the reproduction laser power calibration process is performed in step S8. If the second timer output has not been obtained, the process proceeds to step S11 to check whether or not the medium has been loaded. If the medium has been loaded, reproduction laser power calibration processing is performed in step S8.

  On the other hand, when 12 hours have passed since the power-on start and the timer output of the first timer 80 is obtained, the process proceeds from step S5 to step S9, and the previous and current time intervals in the time interval set by the second timer are set. The temperature difference ΔT of the environmental temperature is detected. In step S1, it is checked whether or not the absolute value of the temperature difference ΔT exceeds a predetermined threshold temperature Tth. If it exceeds, reproduction laser power calibration processing is performed in step S8. If not, after checking whether or not a medium is inserted in step S11, the process returns to step S4 again.

  FIG. 7 shows details of the reproduction laser power calibration process in steps S2 and S8 of FIG.

  In the calibration processing of the reproduction laser power in FIG. 7, first, in step S1, seek to the measurement track in the test zone, which is a zone that is not used for data recording by the user secured as the system area, and is on-track. Set to the control state. The measurement track may be reproduced after recording measurement data used for calibration each time, or a track in which data has already been written may be used as the measurement track.

  In step S2, the reproduction laser power is set to an initial value W0 = 1.0 mW. Subsequently, in step S3, the reproduction output level is read. In step S4, the previous reproduction output level is compared with the reproduction output level read this time. If this time is larger, the reproduction laser power W is set to ΔW, for example, 0 in step S5. Increase by 25 mW and read the playback output level again in step S3.

  If the previous reproduction output level is equal to or smaller than the current reproduction output level in step S4 while the processes in steps S3 to S5 are repeated, the process proceeds to step S6. The optimum reproduction laser power is calculated by adding a constant value Wc, for example, 1.0 mW to the value of the reproduction power W.

  FIG. 8 shows a process when an interrupt due to an access request is received from the upper optical disk control device during the reproduction laser power calibration process of FIG.

  If there is an access request interrupt from the host device, it is first checked in step S1 whether or not the host priority mode is set. If the host priority mode is set in the priority mode setting unit 86, the calibration process is interrupted in step S2, and the read, write, or erase operation corresponding to the interrupt request is performed in step S3. When the access request interrupt process is completed, the interrupted calibration process is resumed in step S4.

  On the other hand, when the setting of the calibration processing priority mode is determined in step S1, a busy response is returned to the host side in step S5, the calibration processing is continued, and the release of the busy response upon completion of the calibration processing is awaited. Thus, the access request from the host side is accepted. Here, until, for example, 12 hours from the first timer elapses after the power-on start of the apparatus, the environmental temperature in the apparatus gradually increases, and the medium temperature of the optical disk also fluctuates accordingly.

  For this reason, for example, calibration of the reproduction laser power every hour by the second timer 82 is required. However, after a certain period of time, the environmental temperature in the apparatus is saturated and stabilized, and in this state, the medium temperature also fluctuates. There is almost nothing. Therefore, for example, calibration processing every hour by the second timer is stopped so that unnecessary calibration of the reproduction laser power is not performed.

  In addition, even when an optical disk is newly inserted into the apparatus by exchanging the cartridge, environmental temperature fluctuations in the apparatus are expected, and at this time, the reproduction laser power is calibrated as the medium is inserted. After that, unless the temperature difference between the previous time and the current time interval by the second timer exceeds a predetermined value, the reproduction laser power is not calibrated.

  As a result, there is a possibility that an access request interruption during the calibration operation will occur from the power-on start until 12 hours when the first timer 80 generates a timer output. Thereafter, the reproduction laser is used unless the environmental temperature in the apparatus changes greatly. Since power calibration is not performed, even if the calibration priority mode is set, there is very little possibility that an access request from the host device is waited for by the calibration operation.

  In the reproduction laser power setting method of the present invention, reproduction power calibration processing is performed to determine the optimum value of the reproduction laser power by performing reproduction operation of the optical recording medium at regular time intervals, and reproduction laser power is determined. If the degree of change in the optimum laser power value determined by the above calibration is less than the previous value, the reproduction laser power calibration process at certain time intervals may be suspended.

  FIG. 9 shows another embodiment of the reproduction laser power calibration processing according to the present invention. In this embodiment, the error rate of the reproduction signal is increased while increasing the reproduction laser power by ΔW = 0.25 mW from the initial value W0. Is measured in step S3, and in step S4, the measurement by increasing the reproduction laser power in increments of ΔW in step S5 is repeated until the error rate becomes equal to or lower than the specified value. A constant value Wc is added to the reproduction laser power, and the optimum reproduction laser power is obtained in step S6.

  In step S4, it is assumed that the envelope of the characteristic curve is detected when the error rate becomes equal to or less than the specified value. However, when the error disappears, the envelope is detected and the optimum reproduction laser power is calculated in step S6. You may make it enter.

  Furthermore, light emission of the laser diode with the optimum reproduction laser power determined by the calibration process is used only for the portion on the track where the magneto-optical recording / reproduction on the disk medium is performed using the reproduction gate signal generated at the time of reproduction. As a result, the continuous driving state during the reproduction of the laser diode by the optimum reproduction laser power can be suppressed, the laser diode can be protected, and the life can be extended.

In the above embodiment, the interchangeable optical disk apparatus in which the optical disk medium is accommodated in the cartridge is taken as an example, but the present invention can also be applied to an optical disk apparatus having a structure in which a plurality of optical disks are fixedly provided. Further, the present invention is not limited by the numerical values shown in the above embodiments.

Principle explanatory diagram of the present invention The block diagram which showed the Example of this invention Functional block diagram of the playback power calibration unit of FIG. Characteristics of reproduction laser power and reproduction signal output with the temperature of the recording medium as a parameter Explanatory drawing of the calibration process of the present invention in the characteristic diagram Flowchart of overall processing of recording / reproducing of the present invention Flowchart of reproduction laser power calibration process of FIG. Flowchart of processing when there is an interrupt request from the host side during calibration in FIG. Flowchart of another embodiment of the reproduction laser power calibration process of FIG. Illustration of conventional media recording Explanatory drawing of conventional medium reading

Explanation of symbols

10: Controller 12: Optical head unit 14: VCM
16: Lens actuator (track actuator)
18: Focus actuator 20: Photo detector 22: Laser diode 24: Electromagnet 26: Temperature sensor 28: Spindle motor 30: Overall control unit 32: Interface control unit 34: Position servo control unit 36: Focus servo unit 38: Light emission power control Unit 40: Bias magnet control unit 42: Motor control unit 44: Tracking error detection circuit 46, 58, 76: AD converter 48, 52, 60: DA converter 50, 54, 70, 72: Driver 64: Laser drive circuit 66: Recording circuit (data modulation circuit)
68: Reproduction circuit (data demodulation circuit)
74: Reproduction power calibration unit 78: Start control unit 80: First timer 82: Second timer 84: Temperature processing unit 85: Calibration processing unit 86: Priority mode setting unit 88: Reproduction laser power set value storage unit

Claims (2)

In a method for setting a reproducing laser power when using an optical recording medium having at least a recording layer for recording data on a substrate and a reproducing layer for reproducing data recorded on the recording layer,
After the first set time set in the first timer means has elapsed from power-on or reset start, a reproduction laser power calibration process is performed to determine the optimum value of the reproduction laser power by performing the reproduction operation of the optical recording medium. ,
Until the second set time set by the second timer means elapses from power-on, reproduction laser power calibration processing is performed each time the first set time elapses by the first timer means, and the second timer means When the first set time by the first timer means elapses after the second set time has elapsed, the reproduction laser power calibration process by the first timer means is suspended, and the operating temperature of the apparatus detected this time is Check the temperature difference with the operating temperature detected last time, and if the temperature difference exceeds the predetermined value, perform the calibration process of the regenerative laser power,
When the optical recording medium is inserted, the reproduction laser power is calibrated regardless of the timer conditions of the first timer means and the second timer means.
A reproducing laser power setting method characterized by the above.
In an optical storage device that performs at least reproduction using an optical recording medium having at least a recording layer for recording data on a substrate and a reproduction layer for reproducing data recorded on the recording layer,
First timer means;
Second timer means;
Reproduction laser power calibration processing means for performing reproduction laser power calibration processing for determining an optimum value of reproduction laser power by performing a reproduction operation of the optical recording medium,
The reproduction laser power calibration processing means includes:
A reproduction laser power calibration process for determining an optimum value of the reproduction laser power by performing a reproduction operation of the optical recording medium after the first set time set in the first timer means has elapsed from power-on or reset start. Done
Until the second set time set by the second timer means elapses from power-on, reproduction laser power calibration processing is performed every time the first set time elapses by the first timer means, and the second timer means When the first set time by the first timer means elapses after the second set time by elapses, the reproduction laser power calibration process by the first timer means is suspended and the apparatus detected this time Check the temperature difference between the operating temperature and the previously detected operating temperature, and if the temperature difference exceeds the specified value, perform the calibration process of the reproduction laser power,
When the optical recording medium is inserted, the reproduction laser power is calibrated regardless of the timer conditions of the first timer means and the second timer means,
An optical storage device.

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