JP2001243649A - Device for recording and reproducing optical information and method for deciding recording power - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical information recording and reproducing device whose recording processing time is shortened, and an information recording and reproducing device in which an excessive current flow to a semiconductor laser is prevented. SOLUTION: Power calibration in the optical information recording and reproducing device is performed in accordance with the device state, and further, laser deterioration or laser destruction is prevented by suppressing the supply of an excessive current to the semiconductor laser.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording / reproducing apparatus for recording / reproducing information on / from an optical information recording medium. The present invention relates to an optical information recording / reproducing device capable of improving data recording control.

[0002]

2. Description of the Related Art In an optical information recording / reproducing apparatus, information is recorded / erased / reproduced by irradiating a recording layer on a disk with laser light from a semiconductor laser as a light source.

However, a semiconductor laser, which is a light source, has a very poor temperature characteristic, and an automatic power control (APC) is required to stabilize the light emitted from the semiconductor laser.
ntrol) technology is used.

A conventional APC circuit will be described with reference to FIG. When light emitted from the semiconductor laser (LD) 2 is received by the photodetector (PD) 6, a detection current 14 flows. The detection current 14 is converted to a voltage 15 by a current-voltage conversion (IV conversion) circuit 7. The amplifier 34 to which the reference voltage 35 is applied to the inverting input terminal inputs the voltage 15 to the non-inverting input terminal and supplies an output that changes according to the voltage 15 to the base of the pnp transistor 35. pnp transistor 3
5 changes the magnitude of the semiconductor laser drive current a11 according to the potential difference between the emitter and the base.

That is, by monitoring the intensity of the emitted light from the semiconductor laser 31 and using the voltage 15 as a negative feedback signal, a constant output is obtained by the amplifier 34.

Further, the optical information recording / reproducing apparatus has a feature that the disc can be exchanged, so that when the disc is changed, or even when the same disc is used, various conditions during recording change.
Variations occur in the recording marks formed on the disk.

Changes in recording conditions include variations in recording sensitivity for each recording / reproducing medium, changes in recording sensitivity of the recording / reproducing medium due to changes in environmental temperature, and fluctuations in the servo state. Even when the focal position is shifted from the position on the recording / reproducing medium, the relative recording sensitivity may change.

In order to improve the recording density of the recording / reproducing medium, it is necessary to form the recording marks with high precision by suppressing the fluctuation of the recording marks even when the recording sensitivity changes.

As a method for stabilizing recording conditions on a disk, for example, test writing (power calibration) as described in JP-A-3-46131 is known.

In power calibration, predetermined information is written in an area different from the original user recording area by changing the recording power, and the written information is reproduced to obtain an optimum recording power.

This power calibration is performed, for example, in JP-A-6-195713, JP-A-8-45101,
This is performed at the time of disc loading, such as disclosed in Japanese Patent Application Laid-Open No. 4-67436, at predetermined time intervals, or before recording user data.

In order to determine the optimum recording conditions in the power calibration, for example, as described in JP-A-6-195713, a dense pattern and a sparse pattern are alternately recorded, and a dense pattern and a sparse pattern are recorded from a reproduced signal. A method is known in which the difference between the average levels of the two, ie, the asymmetry, is detected, and the recording power at which it becomes substantially zero is determined as the optimum recording condition.

[0013]

However, the conventional test writing (power calibration) timing is performed at the time of disk loading or every time before user data recording, and limits the performance of the apparatus in terms of data recording speed. There was a problem.

When the power calibration is executed for a predetermined time, the power calibration is performed irrespective of a change in the internal temperature of the apparatus or a change in the state of the semiconductor laser. Therefore, the laser output can be increased even when no correction is necessary. And the laser deterioration progresses, and an extra power calibration area (Power Calibration Area: “P
CA ").

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide an information recording / reproducing apparatus and method which enables an operation when power calibration is appropriate and shortens a recording operation processing time. To provide.

Another object of the present invention is to reduce the deterioration of the semiconductor laser and prevent the laser from being destroyed, reduce the consumption area or the frequency of use of the PCA area, and reduce the amount of processing from the host device. An object of the present invention is to provide an information recording / reproducing apparatus and method. Other objects of the present invention,
Advantages, features, and the like will be immediately apparent to those skilled in the art from the descriptions of the following embodiments and the like.

[0017]

According to the present invention, there is provided an optical information recording / reproducing apparatus which irradiates a recording laser capable of varying power to an optical recording medium and a reproducing laser beam, and a semiconductor laser output device. And a laser driver circuit for supplying a current to the semiconductor laser, and using the output of the photodetector to drive the laser driver so that the semiconductor laser light output has a predetermined constant value. A current control circuit for controlling a current, a current determination circuit for determining that a drive current to the laser driver is larger than a predetermined value, and a drive controller for controlling a recording start operation of the semiconductor laser, A control circuit performs a power calibration for optimizing a laser power at the time of recording based on an output of the current discrimination circuit. Request to Controller performs power calibration operation by the request.

In the current control circuit, the laser drive current supplied to the laser driver circuit at the time of recording is smaller than the laser breakdown current in accordance with the laser drive current required to make the optical output of the semiconductor laser a predetermined constant value. An excessive current estimating circuit for estimating an excessive current is provided, and when it is determined that the laser drive current is excessively large than the laser breakdown current, control is performed so as to prohibit the semiconductor laser from emitting recording power.

In the above current control circuit, when the laser drive current necessary for setting the semiconductor laser light output to a predetermined constant value exceeds a predetermined value, the laser drive current at the time of recording becomes larger than the laser breakdown current. An excessive current estimating circuit for estimating the occurrence is provided, and control is performed so that the supply current to the laser does not flow more than the laser breakdown current.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to clarify the above and other objects, features and advantages of the present invention, embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

In one preferred embodiment of the present invention, referring to FIG. 1, it has a laser light emitting means for recording information on an optical information recording medium and for reflecting light reflected from the optical information recording medium. In an optical information recording / reproducing apparatus for receiving and reading information, before performing recording in a user data area, power calibration is performed in a PCA area on the optical information recording medium to optimize the recording power. A power calibration operation execution request is sent to the drive controller (50) according to the reproduction drive current.
Power control circuit (10).

A power control circuit (10) detects a change in the temperature state of a laser or a device detected by a change in drive current to a light source that generates a light beam for recording / erasing / reproducing that irradiates the optical information recording medium. Power calibration execution request to drive controller (50) (30)
Is output.

According to the embodiment of the present invention, it is not necessary to perform power calibration at predetermined time intervals as in the conventional apparatus, and the power calibration is performed according to a temperature change in the apparatus. In addition, the power calibration is performed in accordance with the temperature change in the apparatus, thereby making it possible to reduce the recording process and the recording operation.

The present invention, in another embodiment, comprises:
Referring to FIG. 6, before recording in the user data area, power calibration is performed in the PCA area on the optical information recording medium, and during the operation of optimizing the recording power, according to the reproduction drive current of the semiconductor laser. The current control circuit of the power control circuit (10) outputs a recording gate output inhibition signal (31) for inhibiting the recording drive current output.

The power control circuit (10) estimates that the drive current at the time of recording may degrade or destroy the semiconductor laser according to the drive current at the time of reproduction, and issues a recording operation execution prohibition request to the drive controller (50). Request to.

In one embodiment of the present invention, the power control circuit (10) performs a control operation for inhibiting output of a recording drive current which causes deterioration or destruction of the semiconductor laser to the semiconductor laser.

According to the embodiment of the present invention having such a configuration, injection of the recording drive current into the semiconductor laser can be prevented beforehand, and deterioration and destruction of the semiconductor laser can be prevented, and consumption of the PCA region can be reduced. be able to.

[0028]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention;

FIG. 1 is a diagram showing a basic configuration of an apparatus according to an embodiment of the present invention. Referring to FIG. 1, this device comprises:
An optical information recording / reproducing apparatus for recording / erasing and reproducing information by irradiating an optical information recording medium 1 with a light beam from an optical head. The optical head section includes a semiconductor laser (LD) 2 as a recording / reproducing light source. , Divided by a light beam splitter (not shown) in the optical head unit of the LD 2, guided to a recording / reproducing beam and a photodetector (not shown), and an output 14 of the photodetector is connected to the power control circuit 10 You.

In the power control circuit 10,
The output 14 of the photodetector of the optical head unit is input, converted to a voltage, amplified, analog-to-digital (A / D) converted, and input to the current control circuit 9. , A recording power drive current 12 and an erase power drive current 13 by using an LD driver (laser driver) 2
0 to output a power calibration request signal 30 to a drive controller 50 that controls the entire optical information recording / reproducing apparatus.

When the drive controller 50 receives the power calibration signal 30, the drive controller 50 moves the head to the PCA area and performs a power calibration operation.

The recording control circuit 60 controls the recording gate 32
The D driver 20 controls the start and end of recording, and supplies the recording data 33 at the same time.

The power control circuit 10 detects a change in the temperature of a laser or a device detected by a change in the drive current to a light source that generates a light beam for recording / erasing / reproducing irradiation on the optical information recording medium. 50
To output a power calibration execution request 30 to the CPU.
That is, in order to execute the power calibration in accordance with the temperature change in the apparatus, the power calibration is performed in accordance with the temperature change in the apparatus, thereby reducing the recording process and shortening the recording operation.

FIG. 2 is a diagram showing a detailed configuration of the first embodiment of the present invention, and is an example of a detailed configuration relating to laser driving of the recording / reproducing system of the optical information recording / reproducing apparatus of the embodiment shown in FIG. Is shown.

Referring to FIG. 2, the apparatus according to the first embodiment of the present invention is an optical information recording / reproducing apparatus for recording / erasing and reproducing information by irradiating an optical information recording medium 1 with a light beam. Yes, a semiconductor laser (LD) 2 which is a light source for recording and reproduction
A collimating lens 3 for shaping the light from the LD 2,
The optical head unit includes a beam splitter (PBS) 4 for splitting light, an objective lens 5 for converging light on the optical information recording medium 1, and a photodetector (PD) 6 for monitoring light intensity from the LD 2.

The light emitted from the LD (semiconductor laser) 2 is
The beam is split by the beam splitter 4 and guided to the recording / reproducing beam and the photodetector 6.

The output of the photodetector 6 is connected to a power control circuit 10.

The power control circuit 10 includes a current-voltage conversion circuit 7, an A / D conversion circuit 8, and a current control circuit 9.

The output 14 of the photodetector (PD) 6 is input to the current / voltage conversion circuit 7 and converted into a voltage and amplified.

The output voltage 15 of the current / voltage conversion circuit 7 is digitized by an analog / digital (A / D) conversion circuit 8, and the output 16 of the A / D converter 8 is supplied to the current control circuit 9.

The current control circuit 9 supplies a reproducing power driving current 11, a recording power driving current 12, and an erasing power driving current 13 to the LD driver 20 according to the digital data which is the output 16 of the A / D converter 8. I do.

Further, a power calibration request signal 30 is connected from the current control circuit 9 of the power control circuit 10 to a drive controller 50 for controlling the entire optical information recording / reproducing apparatus.

Upon receiving the power calibration signal 30, the drive controller 50 moves the head to the PCA area and performs a power calibration operation.

The recording control circuit 60 controls the recording gate 32 to
The D driver 20 controls the start and end of recording, and supplies the recording data 33 at the same time.

The power control circuit 10 and the recording control circuit 60 are connected to the drive controller 50 via the interface controller 70.

Next, the configuration of the current control circuit 9 will be described. FIG. 3 is a diagram illustrating an example of the configuration of the current control circuit 9.

The difference calculation circuit 21 calculates a difference between the output 16 from the A / D converter 8 and a reference value determined by the laser emission intensity.

The operation of the difference calculation circuit 21 and the set value control circuit 22 is started by the start signal 18 of the set value control start timing generation circuit 24.

The set value control circuit 22 calculates the updated current value according to the difference signal 17 and sends the control data 19 to the read / write / erase set value current conversion circuit 23 and the current discrimination circuit 25.

Reproducing, recording, and erasing set value current conversion circuit 23
Converts the voltage value of the control data 19 into a current, and outputs a reproduction driving current 11, a recording driving current 12, and an erasing driving current 13.

The current discrimination circuit 25 discriminates the current amount based on the control data relating to the reproduction drive current 11 in the control data 19, and outputs a power calibration request signal 30 when the current amount is larger than a predetermined value.

Hereinafter, the operation of the first embodiment of the present invention will be described. FIG. 4 is a flowchart showing the control operation of the current control circuit 9.

That is, when the optical information recording medium 1 is mounted on the information recording / reproducing apparatus and the reproducing power is emitted, a reference value and a state setting value D are set (step 41).

The reference value is a value corresponding to the laser emission intensity. The set value control circuit 22 controls the laser drive current so that the laser emission intensity matches the reference value, so that the emission intensity at the time of reproduction is reduced. Operate to be constant.

The state set value D is, for example, a set value of the current between the drive currents Ia and Ib shown in FIG. 10, and corresponds to D in FIG. 11, and D is a determination value for requesting power calibration.

When the semiconductor laser (LD) 2 starts to emit light, a signal flows to the PD 6 and the light emission intensity of the LD 2 is detected.

Next, the difference Δ between the output 16 of the A / D converter 8 and the reference value is calculated (step 42).

The difference Δ is converted into a current set value C (step 43), and added or subtracted from the supply current Current to obtain an updated supply current Current (step 44).

It is determined whether or not the updated Current is equal to or smaller than the state set value D (step 45). If the current does not exceed the state set value D (YES in step 45), the reproduction current set value is updated (step 48). ), Output the updated supply current (step 49), and at the same time, return to the processing of step 42 for performing the difference Δ calculation.

On the other hand, the update supply current Current is the state set value D
If it exceeds (NO in step 45), the ambient temperature has changed, and a power calibration operation request is output (step 46).

Subsequently, the updated supply current is output (step 49), and the process returns to step 42 in which the difference Δ is calculated.

FIG. 5 is a diagram showing an example of the operation timing of the current control circuit 10 according to the first embodiment of the present invention. The operation of the first embodiment of the present invention shown in FIG. 2 will be described in detail below with reference to FIGS.

The operation is started by the start signal 18 of the set value control start timing control circuit 24.

The state 61 will be described. When the output 16 of the A / D converter 8 becomes larger than the reference value, the difference amount Δ output 17 from the reference value becomes a positive value (step 4 in FIG. 4).
2).

The current setting value-C (step 43 in FIG. 4) corresponding to the updated current amount for correcting this is determined by the supply current Current
, To obtain the updated supply current Current (step 44 in FIG. 4).

At this time, since the update supply current Current does not exceed the current Id, data setting of each drive current is performed (Step 48 in FIG. 4).

The current is converted according to the set value and output (step 49 in FIG. 4), and thereafter, the process returns to the first step 42.

Next, the state 62 will be described. When the output 16 of the A / D converter 8 is equal to the reference value, the difference Δ from the reference value becomes zero (0) (Step 42 in FIG. 4).

The updated current amount becomes 0, and the current set value 0 (step 43 in FIG. 4) is added to the supply current Current to obtain the updated supply current Current (step 44 in FIG. 4). At this time, since the update supply current Current does not exceed the current Id, data setting of each drive current is performed (Step 48 in FIG. 4).

The current is converted according to the set value and output (step 49 in FIG. 4), and the process returns to step 42.

Next, the state 63 will be described. When the output 16 of the A / D converter 8 becomes smaller than the reference value, the difference amount Δ output 17 from the reference value becomes a negative value (step 43 in FIG. 4). The current setting value + C (step 43 in FIG. 4) corresponding to the update current amount for correcting this is added to the supply current Current to obtain the update supply current Current (step 4 in FIG. 4).
4). At this time, since the updated supply current Current has exceeded Id and has reached the temperature at which power calibration is performed (step 45 in FIG. 4), a power calibration operation request is output (step 46 in FIG. 4).

Subsequently, data for each drive current is set (step 48 in FIG. 4). The current is converted according to the set value and output (step 49 in FIG. 4), and the process returns to step 42.

In state 64, the output 16 of the A / D converter 9 is equal to the reference value, and the difference Δ from the reference value is zero (0) (step 42 in FIG. 4). The update current amount becomes 0, and the current set value 0 (step 43 in FIG. 4) is changed to the supply current Cu.
The current is added to the rrent to obtain an updated supply current Current (step 44 in FIG. 4), and data for each drive current is set (step 48 in FIG. 4). The current is converted according to the set value and output (step 49 in FIG. 4), and the process returns to step 42.

Next, a second embodiment of the present invention will be described in detail with reference to the drawings. FIG. 6 is a diagram showing the configuration of the second exemplary embodiment of the present invention. Referring to FIG. 6, the power control circuit 10 and the drive controller 50
, A recording gate output inhibition signal 31 is provided. This apparatus is an optical information recording / reproducing apparatus for recording and reproducing information by irradiating the optical information recording medium 1 with a light beam,
Semiconductor laser (LD) as light source for recording / erasing and reproduction
2. A collimating lens 3 for shaping the light from the LD 2, a beam splitter (PBS) 4 for splitting the light, an objective lens 5 for converging the light on the optical information recording medium 1, and a photodetector for monitoring the light intensity from the LD 2 ( PD) 6 in the optical head section. The light of the LD 2 is split by the beam splitter 4 and guided to the recording / reproducing beam and the photodetector 6.

The output of the photodetector 6 is connected to the power control circuit 10. The power control circuit 10
It comprises a current-voltage conversion circuit (IV conversion circuit) 7, an analog-digital (A / D) conversion circuit 8, and a current control circuit 9.

The output 14 of the photodetector 6 is input to the current-voltage conversion circuit 7, converted into a voltage, amplified, and the output 15
Is digitized by an A / D conversion circuit 8, and an output 16 of the A / D converter 8 is supplied to a current control circuit 9.

The current control circuit 9 controls the reproduction power drive current 1 according to the output 16 (digital data) of the A / D converter 8.
1, recording power drive current 12, erase power drive current 13
Is supplied to the LD driver 20.

Further, a power calibration request signal 30 and a recording gate output inhibition request signal 31 are connected from the power control circuit 10 to a drive controller 50 for controlling the entire optical information recording / reproducing apparatus.

The recording gate output inhibition signal 31 is a control signal for preventing the drive controller 50 from outputting a recording gate to the recording control circuit 60.

The recording control circuit 60 controls the recording gate 32 to
The D driver 20 controls the start and end of recording, and supplies recording data 33.

The power control circuit 10 and the recording control circuit 60 are connected to the drive controller 50 via the interface controller 70.

When the power calibration signal 30 is received when the recording gate output inhibition signal 31 is not output, the drive controller 50 moves the head to the PCA area and performs the power calibration operation.

When the recording gate output inhibition gate signal 31 is output, the power calibration operation is not performed.

Next, the configuration of the current control circuit 9 according to the second embodiment of the present invention will be described. FIG. 7 is a diagram showing a configuration of the current control circuit 9 according to the second embodiment of the present invention.

Referring to FIG. 7, the difference calculation circuit 21
The difference between the output 16 from the A / D converter 8 and the reference value is calculated. Start signal 1 of set value control start timing generation circuit
8, the operation of the difference calculation circuit 21 and the set value control circuit 22 is started.

The set value control circuit 22 calculates an updated current value in accordance with the difference signal 17 and controls the read / write / erase set value current conversion circuit 23, the current determination circuit 25, and the excessive current estimation circuit 26. The data 19 is sent.

Reproducing, recording, and erasing set value current conversion circuit 23
Converts the voltage value of the control data 19 into a current, and outputs a reproduction driving current 11, a recording driving current 12, and an erasing driving current 13, respectively.

The current discrimination circuit 25 outputs a power calibration request signal 30 according to the control data 19 of the reproduction drive current 11.

The excessive current estimation circuit 26 detects the reproduction drive current 1
A recording gate output prohibition request signal 31 is output according to the control data 19.

The control data 19 corresponds to the set value on the x-axis in FIG. 11, and E is the set value E in FIG.
e, and corresponds to the drive current Ie in FIG.

FIG. 8 is a flowchart showing the operation of the current control circuit 9 according to the second embodiment of the present invention. Referring to FIG. 8, in the operation of the current control circuit 9 of the second embodiment of the present invention, in addition to the operation of the current control circuit 9 of the first embodiment shown in FIG. A step 47 is provided for determining whether there is a possibility that a laser deterioration or an excessive breakdown current may flow during recording.

The optical information recording medium 1 is mounted on the information recording / reproducing apparatus, and the reference value and the state setting values D and G are set (step 41). This reference value is a value corresponding to the laser emission intensity, and the set value control circuit 22 controls the laser drive current so that the laser emission intensity becomes the reference value.

The state set value D is, for example, a set value of a current between the drive currents Ia and Ib shown in FIG.
And a determination value for requesting power calibration.

At the time of recording, an overcurrent prevention set value G (set value G in FIG. 11) and an update drive current Curren, which are judged to have a possibility of causing an overcurrent for laser deterioration or laser destruction.
When the updated drive current Current exceeds the overcurrent prevention set value G (YES in step 47), an operation of outputting the recording gate output prohibition request 31 to the drive controller 50 (step 51) is performed.

In response, the drive controller 5
0 prohibits the output of the recording gate 32 to the LD driver 20.

Although not shown in FIG. 7, when the set value control circuit 22 outputs the recording gate output prohibition request 31,
The power calibration request output may be invalidated.

Next, another form of control operation of the current control circuit 9 according to the second embodiment of the present invention will be described. FIG.
9 is a flowchart for explaining another control operation of the current control circuit 9 according to the second embodiment of the present invention.

Referring to FIG. 9, a step of determining the occurrence of a power calibration request output (step 4)
After 5), there is provided an overcurrent setting prevention step 47 for determining whether or not the update current Current has exceeded an overcurrent prevention setting value F which is determined to possibly cause laser deterioration or laser destruction overcurrent.

If the updated drive current Current exceeds the overcurrent prevention set value F at which it is determined that there is a possibility of causing laser deterioration or laser destruction overcurrent, the recording drive current becomes a drive current that is not problematic for the semiconductor laser. A set value H is set (step 50).

The reproduction current is set as it is (step 51), and the process returns to step 42 for performing the difference calculation (step 42).

If the updated drive current Current does not exceed the overcurrent prevention set value F, which is determined to have a possibility of causing laser deterioration or laser destruction overcurrent, each set value is output and the step 42 of the difference calculation is performed. (Step 42).

The driving current set value H corresponds to, for example, Ih in FIG.

As described above, since the drive current of the semiconductor laser LD2 is controlled by the drive current set value Current, the reproduction current amount and the ambient temperature can be monitored simultaneously. Therefore, since it is known that the light emission intensity changes with respect to the ambient temperature and the drive current of the LD 2, the power calibration operation start timing can be controlled. Moreover, there is no need to perform power calibration at predetermined time intervals,
Since power calibration is performed in response to temperature changes in the device, power calibration is performed in accordance with the temperature changes in the device, and it is possible to reduce the processing at the time of recording, shorten the operation at the time of recording, and reduce the consumption of the PCA area. Become.

Further, in this embodiment, since the current output limiting structure is provided, the drive current during the power calibration operation may deteriorate or destroy the semiconductor laser by monitoring the drive current set value Current. It can be predicted that there is.

As a result, laser destruction can be prevented before sending an excessive drive current to the semiconductor laser. As a result, the number of times that an excessive drive current is inadvertently applied to the laser can be reduced, and the life of the laser can be extended.

In addition, since the output of the recording drive current is prohibited by the drive current, there is an effect that it is safer than the configuration in which the recording power is emitted and fed back in terms of the laser drive current management.

FIG. 10 shows an example of the relationship between the drive current of the semiconductor laser and the emission intensity when the ambient temperature is used as a parameter. The semiconductor laser is operated at an environmental temperature Ta,
As Tb, Tc, and Te (Ta <Tb <Tc <Te) increase, the laser oscillation threshold current increases, and for the same light intensity Pr or Pw, the driving currents Ia, Ib, I
c and Ie increase in the order of Ia → Ib → Ic → Ie.
This indicates that when the environmental temperature changes, the light emission intensity differs with the same drive current.

Further, the current-light intensity characteristics of the semiconductor laser change with time. In particular, the light intensity decreases with respect to the drive current. FIG. 11 shows the relationship between the set value and
An example of the correspondence of the drive current of the semiconductor laser is shown.

The contents of the drawings referred to in the description of the above embodiments are merely for describing and exemplifying the present invention, and are not for limiting the present invention.

Although the difference Δ calculation uses an A / D converter, the same effect can be obtained by using a counter and a comparator.

In the above embodiment, the optical information recording medium is a phase-change optical disk, but may be a magneto-optical disk or a write-once disk.

Further, as the writing control of the semiconductor laser, the control power is binary control of recording and erasing, but the number of reproducing power control, the number of writing power control and the number of erasing power control are not limited.

As described above, the present invention is not limited to the above-described embodiment, but includes various modifications and alterations that can be made by those skilled in the art within the scope of the principles and spirit of the claims.

[0114]

As described above, according to the present invention,
The following effects are obtained.

A first effect of the present invention is that it is possible to derive an optimum recording condition under a condition appropriate for a change in the characteristics of the apparatus.

The reason for this is that, in the present invention, a timing for performing a power calibration operation for deriving an appropriate recording (erasing) power in response to a change in device characteristics such as a change in environmental temperature or a change in the state of a semiconductor laser is generated. This is because there is provided a means for performing this.

The second effect of the present invention is that unnecessary recording operation can be omitted, user data recording processing time can be shortened, and unnecessary use of the PCA area can be avoided. That is to do.

The reason for this is that, in the present invention, it is possible to derive the optimum recording conditions under appropriate conditions with respect to changes in the device characteristics such as changes in the ambient temperature and changes in the state of the semiconductor laser. Because he did.

A third effect of the present invention is that a laser destruction or deterioration drive current is not injected into the laser, and the destruction or deterioration of the laser can be prevented.

The reason for this is that, in the present invention, the means for predicting the possibility that the laser drive current emits a laser destruction current or a deterioration current is provided in advance, so that a request to inhibit the recording operation is output to the drive controller. This is because the recording operation can be prohibited.

A fourth advantage of the present invention is that the laser can be protected and the laser life can be extended.

The reason for this is that, in the present invention, the laser drive current is configured to prohibit the supply of the laser destruction current or the deterioration current, so that even if the drive controller performs the recording operation, the drive that causes the laser destruction or deterioration is performed. This is because no current is supplied.

As described above, according to the present invention, the power calibration operation can be performed at a suitable time, and the optimum write laser power can be maintained without increasing the data recording processing time.
Also, by reducing the light emitting operation, the consumption of the PCA area is reduced,
Laser degradation can be prevented, and its practical value is extremely high.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 3 is a diagram illustrating a configuration of a current control circuit according to a first example of the present invention.

FIG. 4 is a flowchart illustrating an operation of the current control circuit according to the first embodiment of the present invention.

FIG. 5 is a timing chart for explaining the operation of the first exemplary embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 7 is a diagram illustrating a configuration of a current control circuit according to a second embodiment of the present invention.

FIG. 8 is a flowchart illustrating an operation of the current control circuit according to the second example of the present invention.

FIG. 9 is a flowchart illustrating another operation example of the current control circuit according to the second embodiment of the present invention.

FIG. 10 is a diagram exemplifying a relationship between a driving current of a semiconductor laser and an emission intensity when temperature is used as a parameter.

FIG. 11 is a diagram illustrating an example of a drive current output with respect to a set value.

FIG. 12 is a diagram illustrating an example of a configuration of a conventional APC circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical information recording medium 2 Semiconductor laser 6 Photodetector 9 Current control circuit 10 Power control circuit 20 Laser driver circuit 21 Difference calculation circuit 22 Set value control circuit 24 Set value current conversion circuit 30 Power calibration request signal 31 Recording inhibition request signal 50 Drive Controller 60 Recording Control Circuit 70 Interface Controller

Claims (15)

[Claims] In a power calibration method for determining a laser power at the time of recording using a power calibration area in an optical recording medium, a laser drive current necessary for setting a laser light output to a predetermined constant value is determined in advance. A recording power determination method, wherein the power calibration is performed to determine an optimum recording power when the value exceeds a predetermined value. 2. A semiconductor laser that irradiates an optical recording medium with a recording laser and a reproduction laser beam whose power can be varied, a photodetector that detects output light of the semiconductor laser, and a laser that supplies a current to the semiconductor laser. A driver circuit, using the output of the photodetector, a current control circuit for controlling a drive current to the laser driver circuit so that the semiconductor laser light output has a predetermined constant value; A current discriminating circuit for discriminating whether or not the drive current is larger than a predetermined value; and a drive controller for controlling a recording start operation of the semiconductor laser. Requests the drive controller to perform power calibration to optimize the laser power during recording based on the determination result. An optical information recording / reproducing apparatus, wherein the drive controller performs a power calibration operation in response to a power calibration request from the current control circuit. 3. A laser driving current to be supplied to the laser driver circuit during recording according to a laser driving current necessary for setting the semiconductor laser light output to a predetermined constant value in the current control circuit. Comprises an excessive current estimation circuit that estimates that the laser drive current is too large, when it is determined that the laser drive current is too large,
3. The optical information recording / reproducing apparatus according to claim 2, wherein the drive controller receives the result of the determination, and controls the semiconductor laser to prohibit the semiconductor laser from emitting recording power. 4. The current control circuit estimates that when a laser drive current necessary for setting the semiconductor laser light output to a predetermined constant value exceeds a predetermined value, the laser drive current becomes larger than a laser breakdown current. An overcurrent estimation circuit, wherein in the overcurrent estimation circuit, when it is determined that the laser driving current is excessively larger than a laser breakdown current,
3. The optical information recording / reproducing apparatus according to claim 2, wherein the drive controller receives the result of the determination, and controls the semiconductor laser to prohibit the semiconductor laser from emitting recording power. 5. An optical information recording / reproducing apparatus for recording, erasing, and reproducing information by irradiating an optical information recording medium with a light beam from an optical head. Is detected by a photodetector and input to a power control circuit.The power control circuit is configured to perform a reproduction drive current based on an output of the semiconductor laser detected by the photodetector,
A recording control current, an erasing drive current, and a current control circuit that supplies a laser driver that supplies a current to the semiconductor laser, and outputs a power calibration request signal to a drive controller that controls the entire device, the drive controller includes: Receiving the power calibration request signal from the current control circuit,
A recording control circuit that controls the head to move to a power calibration area (PCA) to perform a power calibration operation, controls recording start and end of the laser driver by a recording gate, and supplies recording data. Wherein the current control circuit of the power control circuit irradiates the optical information recording medium, recording, erasing, detecting a change in drive current to the semiconductor laser that generates a light beam for reproduction, the semiconductor Based on the change in the temperature of the laser or device, the drive controller
An optical information recording / reproducing apparatus, which outputs the power calibration request signal. 6. A power control circuit comprising: a current / voltage conversion circuit for converting a light detection signal of the photodetector into a voltage; and an analog / digital converter for converting an output of the current / voltage conversion circuit into a digital signal. The current control circuit receives a digital output of the analog-to-digital converter as an input, and controls a drive current to the laser driver so that an optical output of the semiconductor laser has a predetermined constant value. 6. The optical information recording / reproducing apparatus according to claim 5, wherein it is determined whether or not the driving current is larger than a predetermined value, and the power calibration request signal is output based on a result of the determination. 7. A difference calculation circuit, wherein the current control circuit calculates a difference between a digital output signal of the analog-to-digital converter and a reference value determined by laser emission intensity, and a difference amount signal output from the difference calculation circuit. In response to the,
A set value control circuit that calculates an update current value and outputs control data; a difference calculation circuit; a set value control start timing generation circuit that controls a start timing of an operation of the set value control circuit; A read / write / erase set value current conversion circuit that converts the current into a current and outputs a read drive current, a write drive current, and an erase drive current; and, among the control data, a current amount is determined based on control data related to the read drive current. The optical information recording / reproducing apparatus according to claim 6, further comprising: a current discriminating circuit that outputs the power calibration request signal when the current value is larger than a predetermined value. 8. An overcurrent estimating circuit for estimating whether there is a possibility that a laser drive current may cause a laser deterioration or a destructive excessive current to flow at the time of recording, wherein the overcurrent estimating circuit comprises: When it is determined that the drive current is excessively larger than the laser breakdown current, the drive controller outputs a recording gate output inhibition request signal, which is a signal for controlling the recording control circuit not to output a recording gate, The controller moves the head to a power calibration area (PCA) upon receiving the power calibration signal when the recording gate output inhibition signal is not output from the power control circuit, and performs a power calibration operation. From the power control circuit, Serial recording control so as not to perform the power calibration operation when the gate output inhibit gate signal is output, optical information recording reproducing apparatus according to claim 5, wherein. 9. A difference calculation circuit for calculating a difference between a digital output signal of the analog-to-digital converter and a reference value determined by a laser light emission intensity, a difference amount signal output from the difference calculation circuit. A set value control circuit that calculates an updated current value in accordance with and outputs control data; a set value control start timing generation circuit that controls a start timing of an operation of the difference calculation circuit and the set value control circuit; Is converted to a current, and a read / write / erase set value current conversion circuit that outputs a read drive current, a write drive current, and an erase drive current; Determining, when the current value is greater than a predetermined value, a current determining circuit for outputting the power calibration request signal; Depending on the data, the the overcurrent estimation circuit for outputting a recording gate output disable request signal, the optical information recording and reproducing apparatus according to claim 6, further comprising a. 10. When the power control request output signal is output from the current control circuit, the overcurrent estimation circuit determines that the update drive current may cause laser deterioration or laser breakdown overcurrent. When it is determined that the overcurrent prevention set value is exceeded, the recording drive current sets a drive current set value that does not cause any problem for the semiconductor laser, and the update drive current does not exceed the overcurrent prevention set value. 9. The optical information recording / reproducing apparatus according to claim 8, wherein a driving current set value of each of a reproducing driving current, a recording driving current, and an erasing driving current is output to the device. 11. A power calibration method for an optical information recording / reproducing apparatus which irradiates a recording laser and a reproducing laser beam from a semiconductor laser capable of varying power to an optical information recording medium, wherein a state change of the semiconductor laser or the apparatus is performed. A power calibration method for an optical information recording / reproducing device, comprising detecting and performing power calibration in accordance with the state change. 12. A recording power determining method for an optical information recording / reproducing apparatus for irradiating a recording laser and a reproducing laser beam from a semiconductor laser capable of changing power to an optical information recording medium, wherein a current supplied to the semiconductor laser is excessive. A method for determining the recording power of an optical information recording / reproducing apparatus, comprising determining whether or not the current is a current and suppressing the supply of an excessive current to the semiconductor laser to prevent laser deterioration and laser destruction. 13. An optical information recording / reproducing apparatus for recording, erasing, and reproducing information by irradiating a light beam from an optical head to an optical information recording medium, which is a recording / reproducing light source in an optical head section. The output of the semiconductor laser is converted into a voltage by using the output detected by the photodetector as an input, and the voltage is converted into a digital signal by an analog-to-digital converter. A power control circuit that supplies an erase drive current to a laser driver and outputs a power calibration request signal to a drive controller that controls the entire device. The drive control circuit includes a power calibration Upon receiving the request signal, the head is moved to the power calibration area (PCA). , A power calibration operation, a recording gate for controlling the start and end of recording by the laser driver, and a recording power determining method for an optical information recording / reproducing apparatus including a recording control circuit for supplying recording data. In the current control circuit of the power control circuit,
When the semiconductor laser starts emitting, a step of calculating a difference Δ between the output of the analog-to-digital converter and a reference value; a step of converting the difference Δ into a current setting value; Adding or subtracting a set value as an update supply current, and comparing and determining whether the update supply current is equal to or less than a predetermined state set value, and when the update supply current exceeds the state set value, Outputting the power calibration request signal and, if the state setting value is not exceeded, updating a reproduction current setting value and outputting an updated supply current. A recording power determining method for an information recording / reproducing apparatus. 14. The current control circuit of the power control circuit, wherein the update drive current and an overcurrent prevention set value determined to have a possibility of flowing an overcurrent that degrades the laser or destroys the laser during recording. Comparing, when the update drive current exceeds the overcurrent prevention set value, outputting a recording gate output inhibition request to the drive controller; and receiving the recording gate output inhibition request, the drive controller Prohibiting output to the laser driver of the above,
14. A method for determining a recording power of an optical information recording / reproducing apparatus according to claim 13. 15. The current control circuit of the power control circuit compares the updated drive current with an overcurrent prevention set value determined to have a possibility of causing laser deterioration or laser destruction during recording. When the update drive current exceeds the overcurrent prevention set value, the method includes setting the recording drive current and the erase drive current to a drive current set value that does not cause any problem for the semiconductor laser.
14. The method according to claim 13, wherein the recording power of the optical information recording / reproducing apparatus is determined.