JP3187594B2 - Optical information recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control circuit for a light source such as a semiconductor laser (laser diode) suitable for use in an optical information recording / reproducing apparatus using an optical disk, an optical card or the like. During the test of the conditions, even in the test area recorded with low output write power, only the synchronization information necessary for data reading is written with normal emission power so that the synchronization pattern can be completely extracted. The present invention relates to an optical information recording / reproducing apparatus with improved reliability.

[0002]

2. Description of the Related Art In recent years, optical disk devices for optically recording / reproducing information by using light emitted from a light source such as a semiconductor laser have been put to practical use and widely used as large-capacity information recording devices. I have. This optical disk device records information by condensing outgoing light from a light source such as a semiconductor laser provided inside the device onto an optical disk, and changing the optical characteristics of a converging point. Reproduction of information is realized by detecting a change state of the dynamic characteristic.

In this optical disk apparatus, recording sensitivity varies from disk to disk, or from recording position to disk, fluctuations in beam intensity of elements constituting a light source such as a semiconductor laser, and recording due to environmental temperature. There is a problem that recording conditions fluctuate due to a change in sensitivity or the like. As a result, the pit length, C / N, jitter, etc. of the recording pits vary, so that the reliability of the reproduced signal cannot be stably ensured.

[0004] In order to remove the influence of such fluctuations in recording conditions, for example, a method has been proposed in which an optimum write power is obtained by a test ("Optical disk recording / reproducing apparatus" in Japanese Patent Application Laid-Open No. Hei 4-2151). In this scheme,
Prior to the actual information recording operation, the test pulse is recorded by sequentially varying the beam intensity (write power) of the laser light, and then the recorded area is reproduced to reproduce the pulse width of the reproduced signal. (That is, the pit length) is detected, and the write power that provides the optimum pit length is determined.

[0005] As described above, if a test of recording a test pulse and a test of reproducing the test pulse are performed prior to actual recording of information, an optimum write power can be obtained. It is possible to avoid the effects.
Although the detailed description is omitted, prior to the actual recording operation, the optimum recording conditions (therefore, the optimum reproduction conditions) are obtained while changing the write power. Various other test methods have been proposed as a test method for recording information at an optimum write power in accordance with the obtained conditions.

That is, a test method for obtaining the optimum recording condition is already known per se, and is generally used in recent years in order to eliminate fluctuations in the recording condition.
Next, an optical disk device having such a recording condition test function will be described with reference to the drawings.

FIG. 5 is a functional block diagram showing an example of the configuration of the main part of an optical disk device having a conventional recording condition test function. In the figure, 1 is an optical head,
LD is a semiconductor laser, 1a is an objective lens, 1b is a photodetector, 2 is a first stage amplifier, 3 is a binarization circuit,
Is a synchronous extraction circuit, 5 is an error corrector, 6 is a data buffer, 7 is a sector detector, 8 is a write timing control circuit, 9 is a semiconductor laser drive circuit (LD drive circuit), 10 is a D / A converter, 11 is CPU, 12 indicates a disk, S1 is a light-receiving output detection signal, S2 is an analog reproduction signal, S3 is a digital reproduction signal, S4 is MO read data, S5 is corrected read data, S6 is write data, and S7 is RF read data. , S8 is RF / MO
A switching signal, S9 is an ID detection signal, S10 is a write pulse, S11 is write power data, S12 is a write gate signal, S13 is a write power control signal, and S14 is LD
Indicates drive current.

First, a configuration of a conventional optical disk device,
A basic operation will be described, and then a test operation for obtaining an optimum recording condition will be described. In the optical disk device of FIG. 5, light emitted from a semiconductor laser LD (laser diode) provided in the optical head 1 is condensed on the disk 12, and the reflected light is detected by the photo detector 1b.

Therefore, from the photodetector 1b,
A detection signal proportional to the reflected light is output as a light reception output detection signal S1. This light reception output detection signal S1 is amplified by the first-stage amplifier 2 to become an analog reproduction signal S2, which is input to the next binarization circuit 3 to select a reproduction method.

That is, the binarizing circuit 3 selectively outputs the RF signal in the pre-formatted area or the MO signal in the data area. Thus, the reproduction method is selected, and the binarized digital reproduction signal S3 is output to the synchronization extraction circuit 4. The synchronization extraction circuit 4 synchronizes the input digital reproduction signal S3, and outputs the RF read data S7 to the sector detector 7 and the MO read data S4 to the error corrector 5, respectively.

The sector detector 7 has a function of detecting at which position in the sector the laser focus point is scanning based on the RF read data S7. An RF / MO switching signal S8 and an ID detection signal S9 are output. On the other hand, the corrected read data S5 whose error has been corrected by the error corrector 5 is sent to the data buffer 6.

The data buffer 6 exchanges recording / reproduction data with the outside of the apparatus via an external interface (not shown). By the way, at the time of data writing, the write data S6 is sent from the data buffer 6 to the write timing control circuit 8.

The write timing control circuit 8 processes the applied write data S6 in accordance with the timing of the ID detection signal S9, generates a write pulse S10, and outputs it to the semiconductor laser drive circuit 9. In this case, the light emission power for writing data, that is,
The write power of the semiconductor laser LD in the optical head 1 is:
It can be set by the CPU 11.

More specifically, the write power data S11 supplied from the CPU 11 to the D / A converter 10 causes the write power data S
A write power control signal S13 proportional to 11 is generated and output to the semiconductor laser drive circuit 9. At the same time, the write pulse S from the write timing control circuit 8
10 is subjected to logical product processing by the write gate signal S12 from the CPU 11 and supplied to the semiconductor laser drive circuit 9.

Therefore, the semiconductor laser drive circuit 9 outputs a pulsed LD drive current S14 obtained by AND operation according to the write gate signal S12 to drive the semiconductor laser LD in the optical head 1. .
The above is the configuration of the conventional optical disk device and the basic operation.

In this optical disk device, in order to obtain the optimum write power, the CPU 11 performs the write operation by changing the write power data S11 during the test as described above, and checks and executes the reproduction state. ing. Here, a detailed configuration of the conventional semiconductor laser drive circuit 9 shown in FIG. 5 will be described.

FIG. 6 is a block diagram showing an example of a detailed circuit configuration of the conventional semiconductor laser drive circuit 9. As shown in FIG. In the figure, LD is a semiconductor laser, TR1 and TR2 are transistors, U11 is an AND gate circuit,
21 is an inverter, WPS is a write power constant current source, R
PS is a read power constant current source, R1 is a resistor, i
W indicates a write current, and iR indicates a read current. The input signal is the same as in FIG. 5, S10 is a write pulse,
S12 indicates a write gate signal, and S13 indicates a write power control signal.

In the drive circuit 9 shown in FIG.
The write pulse S10 and the write gate signal S12 are input to the AND gate circuit U11 and subjected to logical product processing. When the result is "1", the transistor TR1 is driven. Also, via the D / A converter 10 of FIG.
The write power control signal S13 (write power control voltage set by the CPU 11) is supplied, and the write power iW is output from the write power constant current source WPS.

The write current iW is applied to the transistor TR
1 to the semiconductor laser LD. This semiconductor laser LD always has a read power constant current source RPS.
Since the read current iR is supplied from the memory cell, during a write operation, these two currents are added and the current (iW +
iR).

On the other hand, when the result of the logical product by the AND gate circuit U11 is "0", the transistor TR2 is driven and the write current iW flows to the dummy resistor R1, so that only the read current iR is supplied to the semiconductor laser LD. Flows. The control operations of the write power and the read power in the conventional optical disk device having the write power test function and the semiconductor laser drive circuit are as described above.

However, the conventional optical disk device has the following problems when the above-described test of the recording conditions is executed in order to obtain the optimum write power.
In such a test, test data is recorded while changing the write power of the semiconductor laser LD.

Then, at the time of reproduction, the write data portion is read. In the data portion, various synchronization patterns for obtaining synchronization information of a reproduction signal are inserted. That is, the sector format of an optical information recording medium such as a magneto-optical disk is determined by the ISO standard, the Japanese Industrial Standard, and the like.

For example, “ID” is an address, “GAP”
Is a gap with no data, “VFO3” is a continuous data pattern for PLL lock, and “SB” (SYNC BYT
E) defines a synchronization signal of a data portion, “DATA” defines a user data area, “RS” (RESYNC) defines a special code for synchronization, and the like. Thus, in each sector:
In addition to “DATA” and “ECC”, a “VFO3” pattern, an “SB” pattern, an “RS” pattern, and the like are inserted (see FIG. 3 described later).

At the time of data reading, synchronization of read data is realized by extracting synchronization information from each of the synchronization patterns of "VFO3", "SB", and "RS". In this case, if the synchronization information is lost, the synchronization information cannot be obtained, so that it is practically impossible to execute the data read.

For example, in the test area in which the write power was set to a low output in the test of the optimum recording condition, the synchronization pattern of "VFO3", "SB", and "RS" necessarily has a low output. Be recorded. as a result,
In this test area, the extraction of the synchronization pattern is incomplete and satisfactory data reading cannot be performed.

As described above, in the writing of data in such a test area and the test of the recording condition by reading the data, in the case of data recorded with a low output write power, there is a problem in extracting a synchronization pattern. Therefore, in the conventional test under the recording condition, there is a problem that the reliability of the result is questioned, and the meaning of the test itself may be lost.

[0027]

According to the present invention, a conventional optical information recording / reproducing apparatus solves such inconveniences that occur when testing optimum recording conditions, and tests data recorded with low output write power. Even in the area, the purpose is to improve the reliability of test results by enabling complete synchronization pattern extraction by enabling recording of only the synchronization information necessary for data reading with normal write power. And

[0028]

According to the present invention, firstly,
In an optical information recording / reproducing apparatus having a recording condition test function of writing data while changing the write power of a light source such as a semiconductor laser and reading the data and measuring a reproduction state, a data portion of each sector is written at the time of data writing. Means for switching the write power between the synchronization pattern portion and the portion other than the synchronization pattern. In performing the test of the recording condition, at the time of data writing, the synchronization pattern portion in the data portion of each sector does not depend on the sector.
Data is written at a constant level of write power, and data is written while changing the write power in portions other than the synchronization pattern.

Second, in an optical information recording / reproducing apparatus having a test function of writing data while changing the write power of a light source such as a semiconductor laser, reading the data, and measuring a reproduction state, data of a sector is read. A write timing control circuit for outputting a normal write power instruction signal, a first write current supply means for supplying a predetermined level of write current to a light source such as a semiconductor laser in every sector, and a semiconductor laser. Etc.
A second light current that supplies a variable light current to the light source
Supply means, and outputs the normal write power signal
In the case where the first write current supply means is used,
If not, use the second write current supply means.
And a switching means.

[0030]

[0031]

According to the present invention, in order to ensure the reliability of the test, even in the test area where the write power is set to the low output state, only the synchronization information necessary for data reading is written with the normal laser emission amount. By performing control as possible, it is possible to completely extract the synchronization pattern. That is, in the conventional device, at the time of the write operation,
The read current iR and the write current iW are both added and supplied. During the read operation, only the read current iR is supplied to the semiconductor laser LD. However, when the write current iW has a low output, all the tests are performed. As a result of recording data at a low output, the synchronization information detected at the time of reading is also reduced.

According to the present invention, regardless of the level of the write current iW, only the synchronization information necessary for data reading is
As can be recorded at a predetermined level of write current, it detects the synchronization pattern portion in the data portion of each sector during the test, at that timing, that control as the normal write current is output.

[0033]

Embodiment 1 Next, an optical information recording / reproducing apparatus according to the present invention will be described in detail with reference to the drawings .

FIG. 1 is a functional block diagram showing an embodiment of a main part of the optical information recording / reproducing apparatus of the present invention. The reference numerals in the figure are the same as those in FIG.
Reference numeral 15 denotes a normal write power instruction signal.

FIG. 1 shows only the changed parts of FIG. 5 so that the features of the present invention can be easily understood. As shown in FIG. 1, the write timing control circuit 8 is configured to newly generate a normal write power instruction signal S15 together with the write pulse S10 of FIG. 5 and output it to the semiconductor laser drive circuit 9. I have.

In this case, the write timing control circuit 8
, The ID detection signal S9 from the sector detector 7,
That is, since the real timing information indicating where the focusing point of the semiconductor laser LD is scanning in the sector is input, the current position of the sector can be detected based on the ID detection signal S9. . This write timing control circuit 8 basically has the same function as that of FIG. 5 described above as a conventional example.

In the present invention, a function of generating a normal write power instruction signal S15 in synchronization with the ID detection signal S9 from the sector detector 7 is added to the write timing control circuit 8. That is, by the control operation in the write timing control circuit 8, the sector of the data portion is
The normal write power instruction signal S15 is output only at the timing of the position where the synchronization pattern of “VFO3”, “SB”, “RS” is recorded.

As described above, in the optical information recording / reproducing apparatus of the present invention, when the write power of the semiconductor laser LD is controlled using the normal write power instruction signal S15 to write the data of the synchronous pattern portion, Instead of the conventional write current (iR + iW), only the synchronization information necessary for data reading is a predetermined level of write current (iR + iN).
It is characterized in that it is recorded with. Other configurations and operations are basically the same as those in FIG. 5 shown as a conventional example.

In FIG. 1, the main points of the optical information recording / reproducing apparatus of the present invention have been described. Next, a specific configuration of the semiconductor laser drive circuit will be described. here,
This will be described in association with FIG. 6 showing a conventional example.

FIG. 2 is a block diagram showing one embodiment of a detailed circuit configuration of the semiconductor laser drive circuit in the optical information recording / reproducing apparatus of the present invention. 6 and FIG. 1, TR3 and TR4 are transistors, U12 and U13 are AND gate circuits, U22 and U23 are inverters, NWPS is a normal write power constant current source, R2 is a resistor, iN usually indicates a write current.

The semiconductor laser drive circuit shown in FIG.
As is clear from comparison with the conventional drive circuit shown in FIG. 6, the circuit shown in FIG. 2 is provided with a normal write power constant current source NWPS, and is supplied with a normal write current iN. The points are clearly different. In the circuit shown in FIG. 2, when the normal write power instruction signal S15 is given from the write timing control circuit 8 in the write operation at the time of the test for obtaining the optimum write power, the normal write current iN is output together with the read current iR. ,
Both currents are added and supplied to the semiconductor laser LD.

FIG. 3 is a time chart for explaining the data write operation of the semiconductor laser drive circuit shown in FIGS. The symbols attached to each waveform correspond to the code positions in FIGS. 1 and 2, and the sector format is an example of Japanese Industrial Standard.

The time chart of FIG. 3 shows a case where data of two sectors is written. During this write operation, the write gate signal S12 is output at "H", and the ID detection signal S12 is output by the sector detector 7 in FIG.
9 is output at "H", the write timing control circuit 8 shown in FIG.
15 is generated and becomes “H”.

From the write timing control circuit 8,
The same write pulse S10 as that of the related art is output. Therefore, the write pulse S10 and the normal write power instruction signal S15 are applied to the semiconductor laser drive circuit of FIG.
Input from the write timing control circuit 8 and
A write power control signal S13 is input from U11 via the D / A converter 10, and a write gate signal S12 is input from the CPU 11.

In FIG. 2, the write power control signal S13 is supplied from the CPU 11 to D / D as described with reference to FIG.
It is set via the A converter 10 and controls the write current iW from the write power constant current source WPS. On the other hand, the newly provided normal write power instruction signal S15 is a signal that is output only in the synchronous pattern portion of “VFO3”, “SB”, and “RS” of the data portion in each sector where data write is performed. .

The write gate signal S12 is also a signal output from the CPU 11 shown in FIG. 5. The write gate signal S12 is a signal for roughly instructing a data write operation, and emits light from the semiconductor laser LD. The write timing control circuit 8 controls a pulse signal to be output from the write timing control circuit 8. In FIG. 2, the read current iR from the read power constant current source RPS is always supplied to the semiconductor laser LD.

At the time of a test, the write current iW for performing a write operation is variably controlled by an instruction from the CPU 11, and is supplied from the write power constant current source WPS. In this case, in FIG. 2, the AND gate circuit U1
The following operation is performed by the logic circuit composed of 1 to U13 and inverters U21 to U23.

First, when the normal write power instruction signal S15 is not output, that is, when the emitted light from the semiconductor laser LD is in a position such as the user area or the ECC area of the data section and the write pulse S10 Is output, the write current iW is supplied to the semiconductor laser LD via the transistor TR1 as in the conventional case. Therefore, in this state, the semiconductor laser LD
, A read current iR and a write current iW flow, and “iR
+ IW ”to emit light when driven.

When the write pulse S10 is not output, the write current iW flows from the transistor TR2 to the dummy resistor R1, so that only the read current iR flows through the semiconductor laser LD. On the other hand, when the normal write power instruction signal S15 is output, the following operation is performed.

First, when the write pulse S10 is output, the normal write current iN supplied from the normal write power constant current source NWPS flows from the transistor TR3 to the semiconductor laser LD.
A read current iR and a normal write current iN flow, and “iR
+ IN ”to emit light. On the other hand, when the write pulse S10 is not output, the normal write current iN is supplied from the transistor TR4 to the dummy resistor R2.
Flows through the semiconductor laser LD, the read current iR
Only flows.

As described above, at the time of data writing in the test under the optimum recording condition, in each sector of the data portion,
In the synchronization pattern portion, the normal write power instruction signal S15
As a result, the read current iR and the normal write current iN flow to the semiconductor laser LD, and the read current i in the user data area DATA and the ECC area in other data sections.
Since R and the write current iW flow, a necessary synchronization pattern can be reliably detected at the time of reading data. Therefore, the reliability of the test under the optimum recording condition can be improved.

[0052]

Embodiment 2 Next, a second embodiment of the present invention will be described .

In the first embodiment, as described with reference to FIG. 2, two types of write currents iW and i
When the data write is performed by switching between N and N, but when the write gate signal S12 is not output, it is not necessary to supply a current to the transistors TR1 to TR4. Thus, the second embodiment is characterized in that such waste is eliminated and power consumption is reduced.

FIG. 4 is a block diagram showing a second embodiment of the detailed circuit configuration of the semiconductor laser drive circuit in the optical information recording / reproducing apparatus of the present invention. The reference numerals in the figure are the same as those in FIG.
Represents an AND gate circuit, and U24 and U25 represent inverters.

In the second embodiment shown in FIG. 4, the operation timing of each signal is the same as that in FIG. 3, so that detailed description is omitted. In the circuit of FIG. 4, since all the transistors TR1 to TR4 are gated by the write gate signal S12, the drive current (the write current iW or the normal write current iN) flows into the dummy resistors R1 and R2 only in the write operation. Only when the gate signal S12 is being output.

When the write gate signal S12 is not output, that is, when the data write is not performed, the semiconductor laser LD and the dummy resistors R1 and R2
No current is supplied to either of them. Therefore, in the non-write state, unnecessary current is prevented from being generated, and
In addition to the same effects as in the first embodiment, an inherent effect that power consumption can be saved is obtained.

As described above, in the optical information recording / reproducing apparatus according to the present invention, in order to detect the optimum write power, the data write operation is performed while changing the write power, and the data is read to reproduce the data. In the test of the recording condition for checking the “V”, even in the test area written with the low output write power, “V
Only the sync pattern such as FO3 "," SB "," RS ", etc. is written with normal write power, so that when the test area is read, the sync pattern can be detected stably. Data can be read while maintaining the synchronization state.

As a result, the reliability of the test for finding the optimum write power of the semiconductor laser LD can be maintained. In the above embodiment, the case of the optical disk device has been mainly described.
It is clear that the same can be applied to a write-once optical disk device, an optical card, and the like, and the present invention is not limited to the embodiment.

[0059]

According to the optical information recording / reproducing apparatus of the first aspect, in order to determine the optimum write power, a test of recording conditions, that is, data writing / reading while changing the write power, is performed.
At the time of reading and testing, even in the test area where the write power was recorded at a low output state, "VFO
Only synchronous patterns such as "3", "SB", "RS", etc. are written (recorded) with normal write power. Data can be read in a synchronized state, and test reliability is maintained.

According to the optical information recording / reproducing apparatus of the second aspect, in order to maintain the reliability of the test by the optical information recording / reproducing apparatus of the first aspect, the write pulse output is performed by the normal write power instruction signal from the write timing control circuit. Sometimes, the write current supplied to the light source such as a semiconductor laser is controlled to be switched between the synchronous pattern section, the user data, and the ECC section. Therefore, the same effect as that of the optical information recording / reproducing apparatus of the first aspect can be obtained.

[0061]

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing one embodiment of a detailed circuit configuration of a semiconductor laser drive circuit in the optical information recording / reproducing apparatus of the present invention.

FIG. 3 is a time chart for explaining an operation at the time of data writing in the semiconductor laser drive circuit shown in FIGS. 1 and 2;

FIG. 4 is a block diagram showing a second embodiment of the detailed circuit configuration of the semiconductor laser drive circuit in the optical information recording / reproducing apparatus of the present invention.

FIG. 5 is a functional block diagram showing an example of a configuration of a main part of an optical disc device having a conventional recording condition test function.

FIG. 6 shows a conventional semiconductor laser drive circuit 9;
FIG. 3 is a block diagram illustrating an example of a detailed circuit configuration.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical head LD Semiconductor laser 1a Objective lens 1b Photodetector 2 First stage amplifier 3 Binarization circuit 4 Synchronization extraction circuit 5 Error corrector 6 Data buffer 7 Sector detector 8 Write timing control circuit 9 Semiconductor laser drive circuit 10 D / A converter 11 CPU

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B ^7/ 00-7/013 G11B 7/125

Claims (2)

(57) [Claims] 1. An optical information recording / reproducing apparatus having a recording condition test function for writing data while changing the write power of a light source such as a semiconductor laser and reading the data to measure a reproduction state. A means for switching the write power between the synchronization pattern portion in the data portion of each sector and the portion other than the synchronization pattern is provided.
In the synchronous pattern portion sectors in the data section of each sector
Write data with a predetermined level of write power regardless of
The write power can be varied in areas other than the synchronization pattern.
An optical information recording / reproducing apparatus characterized by writing data while writing. 2. An optical information recording / reproducing apparatus having a test function of writing data while changing the write power of a light source such as a semiconductor laser, reading the data, and measuring a reproduction state. In the synchronous pattern section, a write timing control circuit that normally outputs a write power instruction signal, and a light source such as a semiconductor laser that has a predetermined level in all sectors.
A first write current supply unit for supplying a write current; and a variable write current supplied to a light source such as a semiconductor laser.
A second write current supply means, said first write current supply hand when outputting the normal write power signal
The second write current when using a stage and not outputting
An optical information recording / reproducing apparatus, comprising: switching means using a supply means .