JP4501810B2 - Editor and laser driving method - Google Patents

Description

  The present invention relates to an editing machine that reads and edits data by irradiating a disk with laser light emitted from a laser diode, and in particular, driving a high-frequency superimposed drive laser diode when turning on and off an attenuator during reproduction. Regarding the method.

  In a disk recording / reproducing apparatus (including an editing machine) that records and reproduces data by irradiating a laser beam emitted from a conventional laser diode (LD) to a disk, a 400-MHz LD is applied to the LD that is DC-driven during reproduction. RIN (Relative Intensity Noise) during reproduction is improved by superimposing a high frequency current to drive the LD with high frequency superposition (see, for example, Patent Document 1). However, on the other hand, since laser light having peak intensity is emitted from the LD, the recorded data is easily erased, and the read stability is reduced correspondingly.

  Recently, a 400 nm wavelength optical disc (Blu-ray) having a recording density four times that of DVD has been developed. In Blu-ray, the laser light power is four times that of DVD per unit area. For this reason, if the LD is driven at a high frequency during reproduction as described above, the recorded data on the disc is easily erased. In addition, in a double-speed PC disk, data is recorded with a material that absorbs and dissipates heat quickly and the LD power is reduced to about 1.5 times that of a single-speed PC. Since the output of the laser beam at the time of recording is low, if the LD is driven at a high frequency during reproduction, the recorded data on the disc is more easily erased. In addition, since the high frequency level to be superimposed is fixed in the conventional high frequency superimposition drive of the LD, the superimposition level varies greatly depending on the characteristics of the LD, and the recorded data on the disc may be erased.

  By the way, some LDs emitting red laser light have a high output (100 mW), and there was no problem even if the ratio of the laser light output during reproduction and the laser light output during recording was large. However, the LD that emits blue laser light is as small as a maximum output of about 50 mW, and the transmission efficiency of the optical system needs to be 18% or more in order to make the peak output of the laser light during recording 7.0 mW. In such a case, the output of the LD during reproduction is as small as about 1.6 mW and must be used in a state with poor RIN. In this case, the RIN is about -110 dB / Hz, and the error rate of the reproduction data is too low to satisfy the product standard. In order to increase the RIN at the time of reproduction, it is only necessary to increase the original output of the LD. If an attenuator (LCD ATT) of 6.0 dB to 9.0 dB is used, the RIN is −125 dB / Hz or less, which satisfies the standard. it can.

  FIG. 6 is a timing chart showing the data recording / reproducing operation of the editing machine. FIG. 6A shows an attenuator on / off control signal for attenuating and adjusting the level of laser light emitted from the LD. FIG. 6B shows the operation of the attenuator (response to the control signal). FIG. 6C shows a detection signal for detecting the operation of the attenuator. FIG. 6D shows a write command for the disk.

  As shown in FIG. 6A, the actual attenuator operates with a delay as shown in FIG. 6B with respect to the control signal for turning on and off the attenuator. Here, when the attenuator is on, it means that the attenuation function of the attenuator is effective, and when it is off, it means that the attenuation function of the attenuator is zero or significantly reduced. Therefore, based on the attenuator operation detection signal as shown in FIG. 6C for detecting whether or not the attenuator actually operates, a write command as shown in FIG. 6D is issued, or FIG. A read gate control signal as shown in FIG. That is, a write command as shown in FIG. 6D with the attenuator turned off is issued, and data is written to and read from the disk.

FIG. 7 is a timing chart showing the data recording operation of the editing machine. FIG. 7A shows a write standby instruction when data is written to the disk. FIG. 7B shows the operation of the attenuator (response to the control signal). FIG. 7C shows a detection signal for detecting the operation of the attenuator. FIG. 7D shows a write command for the disk. In this case as well, data is written when the attenuator is off, as in FIG.
JP 2000-149302 A (page 4-10, FIG. 1)

  As described above, in the conventional editing machine, as shown in FIGS. 6D and 7D, there is a write standby period 100 in which the attenuator is turned off before and after writing to the disk. The reason for turning off the attenuator during this write standby period is to enable high-speed editing without the loss time caused by turning the attenuator on and off. Even in such a write standby period 100, the LD emits a laser beam for reproduction by high frequency superposition driving. If the high-frequency superimposition level is optimized when the attenuator is turned on, turning off the attenuator in such a write standby period 100 will improve RIN, but the high-frequency superimposition level will rise and the write data will disappear. Since the reproduction durability deteriorates and the possibility that the recorded data is erased becomes extremely high in some cases, the reproduction durability is fatally lowered.

  The present invention has been devised in view of the above circumstances, and an object of the present invention is to eliminate a decrease in reproduction durability during the standby period of the apparatus and to stably edit data without erasing recorded data. It is an object of the present invention to provide an editor and a laser driving method that can be performed.

  In order to achieve the above object, the present invention is an editing machine for reading and editing data by irradiating a disk with laser light emitted from a laser diode, wherein the laser diode is responsive to an operation mode in the editing machine. A laser driver for supplying a drive current, a high-frequency superimposing means for superimposing a high-frequency current on the drive current, an attenuator inserted into an optical system for irradiating the disk with the laser light to attenuate the level of the laser light, Attenuator control means for controlling the attenuation level of the attenuator according to the operation mode, and when the attenuation level of the attenuator is small or zero by the attenuator control means in a period other than the period in which the operation mode reads data from the disk, Control means for reducing the superposition level of the high-frequency current to a low level; Characterized in that it Bei.

  As described above, in the present invention, during the period of reading data from the disk, the high-frequency high-frequency current is superimposed on the drive current (DC current) of the laser diode to drive the laser diode at a high frequency, thereby improving the RIN during reproduction. Thus, the error rate of the reproduction data is reduced. However, when the attenuator is off during other periods (standby periods), the laser diode is driven by low-level high-frequency superposition, and the disk is irradiated with laser light having a low peak level emitted from the laser diode. Read only the pickup address. As a result, even when the attenuator inserted in the optical system for laser light irradiation provided before and after the data writing, for example, during the writing standby period is off, the laser light with a small peak power is irradiated onto the disk. Therefore, it is possible to prevent the reproduction durability from being lowered and to prevent the recorded data from being erased. In the above-described standby period, since only the address where the optical pickup is located needs to be read from the disk, there is no problem even if the RIN deteriorates due to low-level high-frequency superimposition. The address can be read with a laser beam.

  According to the present invention, the high-frequency high-frequency current is superimposed on the DC drive current of the laser diode during the period of reading data from the disk to drive the laser diode in a high-frequency manner, and the attenuator is turned off during the other period (standby period). In some cases, the laser diode is driven by low-level high-frequency superimposition, and the disk is irradiated with laser light having a low peak level emitted from the laser diode, thereby eliminating the deterioration in reproduction durability during the standby period. The data can be stably edited without being erased.

  For the purpose of preventing the recorded data from being erased by eliminating the decrease in the reproduction durability during the standby period of the editing machine, the high-frequency high-frequency current is superimposed on the drive current of the laser diode during the period of reading the data from the disk, During other periods (standby periods) when the attenuator is off, the laser diode is driven by a low-level high-frequency superimposed drive.

  FIG. 1 is a block diagram showing a configuration of a laser drive control circuit of an editing machine according to an embodiment of the present invention. The laser drive control circuit 80 adjusts the level of the high-frequency current output to the CPU 1 that controls the operation of this circuit, the memory 2 that stores programs and data for the CPU 1 to operate, the high-frequency oscillator (OSC) 3, and the laser driver 5. At the same time, the level controller 4 that outputs and stops the high-frequency current, the laser driver 5 that drives by supplying a drive current to the laser diode (LD) 8, and the laser light output of the LD 8 automatically according to the detection voltage of the front photodiode 9. An APC controller (automatic output controller) 6 for controlling, a D / A converter 7 for converting a control signal from the CPU 1 into an analog signal and outputting it to the level controller 4, and an LD temperature sensor 10 for detecting the temperature of the LD 8 are provided. The CPU 1 of the laser drive control circuit 80 is a system controller of the apparatus. Receive various commands and control signals from the controller 30.

  Next, the operation of the present embodiment will be described with reference to the timing chart of FIG. The system controller 30 reads the data from the disk (not shown) when the read gate signal 105 shown in FIG. 2E is at a high level and the period other than the data writing period shown in FIG. In the standby period), the high-frequency superposition mode control signal 106 shown in FIG. 2F is set to the low level, and the high-frequency current superposition level is set to the CPU 1 at a low level (high-frequency current superposition on / off). A command to set ΔIL = 1 mA) is issued. As a result, the CPU 1 performs control to output a low-level high-frequency current from the level controller 4 to the laser driver 5 via the D / A converter 7. Therefore, during this standby period, the laser driver 5 is driven so that a laser beam generated by supplying a DC current superimposed with a low-level high-frequency current to the LD 8 is emitted from the LD 8.

  At this time, the laser light emitted from the LD 8 is received by the front photodiode 9 and the received light level is output to the APC controller 6. The APC controller 6 controls the laser light emitted from the LD 8 to have a predetermined output by controlling the output current of the laser driver 5 based on the light reception level. In the above-described standby period, since only the address on the disk on which the optical pickup housing the LD 8 or the like is located can be read from the disk, there is no problem even if RIN deteriorates due to the low high-frequency current superposition level. Actually, the address can be read out by the laser beam by the low level high frequency current superposition driving of the LD 8.

  In order to read this address, it is sufficient if the wobble of the disk can be reproduced. The wobble is formed by meandering the lands. The wobble is swept up by a circular laser beam and the reflected light is divided by a half-divided photodiode. When the reproduction is performed, a wobble signal is obtained by performing a process such as subtracting with the same average level of the received light signals obtained from the respective division units, so that even if the RIN deteriorates and the noise of the LD 8 slightly increases, there is an effect. The wobble signal can be read out.

  As shown in FIG. 2A, the system controller 30 outputs an attenuator control signal 101 for turning on and off an attenuator inserted in an optical system (not shown), and turns on and off the attenuator as necessary. 2B shows the response operation of the attenuator with respect to the attenuator control signal 101 described above. This response operation is detected as shown in FIG. 2C, and the operation detection signal 102 of the attenuator is sent to the system controller 30. Will be returned.

  The system controller 30 sets the write control signal 103 to a low level as shown in FIG. 2D during a period in which the attenuator is turned on by the detection signal 102 so as to write data to the disk. 103 is output to the CPU 1. When the write control signal 103 becomes low level, the CPU 1 controls the laser driver 5 after confirming that the operation detection signal 102 of the attenuator input from the system controller 30 is low level and the attenuator is off. Is driven by outputting a current in the writing mode to the LD 8, and a laser beam whose output is larger than that during reproduction or standby is emitted from the LD 8.

  At that time, the front photodiode 9 receives the laser beam emitted from the LD 8 and outputs the received light level to the APC controller 6. The APC controller 6 controls the output current of the laser driver 5 to the LD 8 based on the received light level, and emits a writing laser beam having a predetermined output from the LD 8. At this time, the laser beam is modulated by the write data, and the data is written on the disk. When the writing control signal 103 becomes high level and the writing period ends, the CPU 1 restores the DC output current to the LD 8 of the laser driver 5, reduces the output of the laser light emitted from the LD 8, and waits for the laser in the standby period. Let it be light.

  Thereafter, the system controller 30 confirms that the attenuator is turned on by the operation detection signal 102 of the attenuator shown in FIG. 2C, and then outputs the read gate signal 105 as shown in FIG. In order to read data from the disk at a high level, a read gate signal 105 is output to the CPU 1. When the read gate signal 105 becomes high level, the CPU 1 performs control to output a high level high frequency current (ΔIL = 2.0 mA) to the level controller 4 via the D / A converter 7 to the laser driver 5.

  As a result, the level controller 4 outputs a high-level high-frequency current input from the high-frequency oscillator 3 to the laser driver 5. As a result, the laser driver 5 drives the LD 8 by superimposing a high-level high-frequency current on the DC current driving the LD 8. Thereafter, when the read gate signal 105 becomes low level (when the data reading period ends), the CPU 1 outputs a control signal for setting the output of the high frequency current to low level via the D / A converter 7. As a result, the level controller 4 sets the high-frequency current output to the laser driver 5 to the low level (ΔIL = 1.0 mA), so that the laser driver 5 drives the LD 8 to superpose the low-level high-frequency current, and outputs the laser beam during the standby period. Return to.

  Next, the data recording operation of the editing machine will be described with reference to the timing chart of FIG. The system controller 30 issues a low active write standby command as shown in FIG. 3A and outputs an attenuator control signal to turn on an attenuator of an optical system (not shown). It operates in response as shown in The system controller 30 receives the operation detection signal 102 as shown in FIG. 3C which has detected the actual operation of the attenuator, confirms that the attenuator is on, and then as shown in FIG. 3D. A low active write control signal 103 is output to the CPU 1. Thereby, the CPU 1 controls the laser driver 5 to output a write mode current from the laser driver 5 to the LD 8 and to emit a writing laser beam having a predetermined output from the LD 8.

  Also in this case, the high frequency superimposition level is set to the low level during the period when the write control signal 103 shown in FIG. 3D is at the low level and the attenuator before and after the period in which data is written to the disk is off. As a result, the laser driver 5 is driven by superimposing the low-level high-frequency current on the standby DC current to the LD 8, so that the output of the emitted laser light is low and the peak output is not large. Is not erased, and the reproduction durability is not lowered.

FIG. 4 shows a characteristic example when the relationship between the original power of the laser diode and the peak power level when a high frequency superposition level when the attenuator is OFF is set to ΔIL = 1.0 mA is performed for a plurality of samples (laser diodes). FIG. From this characteristic diagram, it can be seen that if the high-frequency level superimposed on the LD 8 is lowered when the attenuator is off, the generation of peak power that lowers the reproduction durability can be suppressed. However, in FIG. 4, samples 1, 2, and 3 have ΔIL = 2.0 mA. Sample2 'and 3' have the characteristic of ΔIL = 1.0mA.

Here, FIGS. 5A and 5B are characteristic diagrams showing a temperature change example of the peak power of the high-frequency superimposed laser diode when the attenuator is off and when the attenuator is on , using ΔIL as a parameter. It can be seen from these characteristic examples that the peak power has a positive temperature characteristic, and the change when the attenuator is off is small, but the change when the attenuator is on is large, and it is difficult to apply high-frequency superposition at low temperatures. Therefore, about 10% high-frequency superimposition level compensation is necessary, and the CPU 1 performs control to increase the high-frequency superposition level when the attenuator is on by about 10% when the temperature is low. That is, according to the value of the LD temperature sensor 10 of the LD 8, the CPU 1 performs control to compensate for the high level high frequency superposition level when the attenuator is on, so that the high frequency level output from the level controller 4 to the laser driver 5 is At low temperatures, the value is increased by 10%.

  According to the present embodiment, when the attenuator is off in a waiting period other than the period in which data is written to the disk and the period in which data is read from the disk, the LD 8 is driven with the high-frequency superposition level set to the low level. Since the laser beam is emitted, the disc is irradiated with a laser beam with a low peak level to prevent a decrease in reproduction durability, and it is possible to prevent problems such as erasure of recorded data during editing. Can perform stable and reliable editing.

  In addition, this invention is not limited to the said embodiment, In the range which does not deviate from the summary, it can implement also with another various form in a concrete structure, a function, an effect | action, and an effect.

It is the block diagram which showed the structure of the laser drive control circuit of the editing machine which concerns on one Embodiment of this invention. 3 is a timing chart for explaining the operation of the laser drive control circuit shown in FIG. 1. 6 is a timing chart for explaining another operation of the laser drive control circuit shown in FIG. 1. It is the characteristic view which showed the relationship between the original power of a laser diode, and a peak power level. It is a temperature characteristic figure of the peak power of a laser diode. It is a timing chart explaining operation | movement of the conventional editing machine. It is another timing chart explaining operation | movement of the conventional editing machine.

Explanation of symbols

  1 ... CPU, 2 ... memory, 3 ... high frequency oscillator (OSC), 4 ... level controller, 5 ... laser driver, 6 ... APC controller (automatic output controller), 7 ... D / A conversion 8 ... Laser diode (LD), 9 ... Front photodiode, 10 ... LD temperature sensor, 30 ... System controller, 80 ... Laser drive control circuit.

Claims (4)

An editing machine that reads and edits data by irradiating a disk with laser light emitted from a laser diode,
A laser driver for supplying a drive current to the laser diode in accordance with each operation mode of a write mode, a read mode, and a standby mode ;
High frequency superimposing means for superimposing a high frequency current on the drive current;
An attenuator that is inserted into an optical system for irradiating the laser beam to the disk and attenuates the level of the laser beam;
Attenuator control means for controlling the attenuation level of the attenuator according to each operation mode ,
In the write mode, the laser driver supplies a drive current that emits a laser beam larger than that in the read mode and the standby mode to the laser diode,
The attenuator control means makes the attenuation level of the attenuator small or zero in the writing mode and the standby mode ,
The high-frequency superimposing means sets the high-frequency current superimposition level to a high level in the read mode, and sets the high-frequency current superimposition level to a low level in the write mode and the standby mode .
Editing machine. Temperature detecting means for detecting the temperature of the laser diode;
Temperature compensation means is provided that compensates by changing the level of the high-frequency current superimposed on the drive current when the attenuation level of the attenuator is high during a period of reading data from the disk in accordance with the temperature of the laser diode .請 Motomeko 1 editing machine according. The laser light is blue der Ru請 Motomeko 1 or 2 editing machine according. 3. The editing machine according to claim 2 , wherein when the attenuation level of the attenuator for attenuating the laser light level is high and the temperature of the laser diode is low, temperature compensation is performed so as to increase the high-frequency current superposition level.

Images