JPH08124162A - Optical disk recording device - Google Patents

Abstract

PURPOSE: To apply automatic output controlling processings to respective levels in recording corrections with respect to plural light emitting levels, also to dispense with high speed automatic output controlling processing and to set arbitrarily recording pulse widths. CONSTITUTION: A pulse generating circuit 11 detects four light emitting data D1 , D2 , D3 and D4 and four hold signals H1 , H2 , H3 and H4 from a recording data D0 and supplies the four light emitting data D1 , D2 , D3 , and D4 to amplifiers 12,13,13 and 15 and also supplies the four hold signals H1 , H2 , H3 and H4 to automatic output control circuits which are not shown in the figure. Driving circuits 16, 17, 18, and 19 supply four light emitting levels respectively corresponding to driving voltages VD1 , VD2 , VD3 , and VD4 from the automatic output control circuits to a laser diode LD.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk recording apparatus for emitting light from a light emitting means according to data and recording an information signal on a disk recording medium.

[0002]

BACKGROUND OF THE INVENTION Generally, the optical disc recording, the input data series is a series of bit information of "1" and "0", changing the minimum inversion interval T _min and a maximum inversion interval T _{m ax} of the input data sequence Are converted into a code symbol sequence that is more compatible with the optical disc. And as a format for recording this code symbol sequence on the optical disc,
There are mark interval recording and mark length recording.

Among them, the mark length recording is based on the code of the code symbol series, for example, NRZI (Non Return to Zero I).
A waveform train is generated by (nverted) modulation, and the light emission of, for example, a laser diode is controlled by changing the pulse width and the light emission level according to the data length of the waveform train to perform recording compensation by thermal recording.

Incidentally, in recent years, the demand for high-density recording has been increasing more and more in optical discs. Therefore, a compensation technique having a plurality of emission levels has been proposed.

[0005]

By the way, for example, in the above laser diode, since the pulse width and the output at the time of light emission are easily affected by the change of temperature, the automatic power control (Automatic Power Control: (Hereinafter referred to as APC) circuit is adopted, but for those having a plurality of light emission levels,
Only a part of them was subjected to APC treatment.

Therefore, a method of individually sampling each level has been considered. That is, the drive voltage V obtained from the APC circuit 50 as shown in FIG.
_D was supplied to the LD drive circuit 60 as shown in FIG. 7, and laser light was output from the laser diode LD.

First, the LD light emission monitor voltage supplied to the APC circuit 50 is passed through the buffer amplifier 51 to the comparator 5.
2 is supplied. The comparator 52 compares the reference voltage from the reference voltage generating circuit 53 with the LD light emission monitor voltage. The reference voltage generation circuit 53 uses the reference voltages V _ref1 and V _ref1 .
_{One of ref2} , _Vref3, and _Vref4 is output according to the switching operation of the changeover switch SW. The output of the comparator 52 is
It is supplied to a low-pass filter (hereinafter, referred to as LPF) 54 and band-limited. The filter output of the LPF 54 is a sample / hold (denoted by S / H in the figure) circuit 5.
5 is supplied. The S / H circuit 55 samples / holds the filter output according to the sample signals S ₁ , S ₂ , S ₃ and S ₄ as shown in FIG. The output of the S / H circuit 55 is output to the LD drive circuit 60 via the driver 57.
_Is supplied as a drive voltage V _D as shown in FIG. Further, the bias voltage V _B as shown in FIG. 8 is also supplied to the LD drive circuit 60 via the driver 58.

Further, the LD drive circuit 60 is supplied with light emission data D _W as shown in FIG. 8 as write data. The light emission data D _W is input to the amplifier 61. The amplifier 61 supplies a balanced output of the emission data D _W to the drive unit 62 as an output signal. The drive unit 62 includes transistors Tr ₁ , Tr ₂ , Tr ₃ and Tr ₄ . The bias voltage V _B is supplied to the base of the transistor Tr ₁ . The emitter of the transistor Tr ₁ is connected to V _EE via the resistor R ₂ ,
Laser diode LD with collector grounded anode
Also connected to the collector of the transistor Tr ₂ is connected to the cathode. The emitter of the transistor Tr _{2 and} the emitter of the transistor Tr ₃ are directly connected to each other and to the collector of the transistor Tr ₄ . The collector of the transistor Tr ₂ is the laser diode LD.
And the collector of the transistor Tr ₁ as described above. The positive signal of the balanced output of the amplifier 61 is supplied to the base of the transistor Tr ₂ . Transistor Tr ₃
Has its collector grounded through a resistor R ₁ . The inverted output of the balanced output of the amplifier 61 is supplied to the base of the transistor Tr ₃ . Transistor Tr
The drive voltage V _D from the APC circuit 50 is supplied to the base of ₄ . The collector of the transistor Tr ₄ is connected to the emitters of the transistors Tr ₂ and Tr ₃ as described above, and the emitter is connected to V _EE via the resistor R ₃ .

The LD drive circuit 60 configured as described above
Is the drive voltage V _D supplied from the APC circuit 50 when the emission data D _W as shown in FIG.
The LD light emission waveform V _L shown in FIG. 8 is generated using the bias voltage V _B and is supplied to the laser diode LD. However, in the method of individually sampling each light emission level as described above, the reference voltage generating circuit 53 in the APC circuit 50 is used.
There was a limit because it was difficult to speed up at.

The present invention has been made in view of the above circumstances, and it is possible to perform automatic output control processing on each level by recording compensation for a plurality of emission levels, and high speed automatic output control processing is unnecessary. The present invention also relates to an optical disk recording device in which the recording pulse width can be arbitrarily set.

[0011]

An optical disk recording apparatus according to the present invention emits light from a light emitting means according to data,
In an optical disk recording device for recording an information signal on a disk-shaped recording medium, a light emission data generating means for generating a plurality of n light emission data according to the data, and n drive voltages by trial writing corresponding to each light emission data. The above problem is solved by having automatic output control means for outputting the light emitting means and n driving means for driving the light emitting means at n light emission levels according to the n drive voltages from the automatic output control means. To do.

In this case, each of the plurality of n light emission levels is calculated and determined as a total sum of the n drive voltages up to the nth.

[0013]

The automatic output control means outputs n drive voltages by trial writing corresponding to a plurality of n light emission data generated by the light emission data generation means, and the n drive means outputs the n drive voltages. Since the light emitting means is driven at n emission levels according to the drive voltage to record the information signal on the disk-shaped recording medium, automatic output control processing is performed on each level by recording compensation for a plurality of emission levels. In addition, high-speed automatic output control processing is unnecessary, and the recording pulse width can be set arbitrarily.

[0014]

Embodiments of an optical disk recording apparatus according to the present invention will be described below with reference to the drawings. This embodiment is an optical disc recording apparatus for irradiating an optical disc having a diameter of 130 mm with a laser beam from a laser diode LD to perform mark length recording according to the data length of a waveform row by thermal recording.

This optical disk recording apparatus comprises a laser diode drive circuit 10 as shown in FIG. 1 and an automatic power control (Automatic Power Control, hereinafter referred to as APC) circuit 20 as shown in FIG. , The drive voltages V _D1 , V _D2 , V _D3 and V _D4 from the APC circuit 20 are respectively applied to the drive units 16, 17, 18 and 1 of the laser diode drive circuit 10.
9, and the laser light is emitted from the laser diode LD. Then, the laser beam is applied to the optical disc to record an information signal corresponding to the record data.

First, the laser diode drive circuit 10
The configuration of will be described.

This laser diode drive circuit 10
1 detects _four emission data D ₁ , D ₂ , D ₃ and D ₄ and four hold signals H ₁ , H ₂ , H ₃ and H ₄ from the recording data D ₀ as shown in FIG. Four emission data D
₁ , D ₂ , D ₃ and D ₄ are connected to amplifiers 12, 13, 14 and 15
To the four hold signals H ₁ , H ₂ , H
₃ and H ₄ a pulse generation circuit 11 to be supplied to the APC circuit 20 in FIG. 2, the drive circuit 16, 17, 18 and 19 balanced output of the amplifier 12, 13, 14 and 15 are supplied
Between the load resistances R ₁ , R ₂ , R ₃ and R ₄ of the drive circuits 16, 17, 18 and 19, the laser diode LD, and the drive circuits 16, 17, 18 and 19 and V _EE. It is composed of inserted resistors R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ .

The pulse generation circuit 11 generates the emission data D ₁ , D ₂ , D ₃ and D ₄ according to the recording data D ₀ shown in FIG. For example, in order to realize the light emission of the laser diode LD, the laser diode light emission waveform is decomposed into light emission data D ₁ , D ₂ , D ₃ and D ₄ according to the light emission level. The drive voltages V _D1 , V _D2 , V _D3 and V _D4 corresponding to the decomposed light emission data D ₁ , D ₂ , D ₃ and D ₄ are input to the respective drive units 16, 17, 18 and 19, and as a result. The laser diode light emission waveform V _L is obtained.

Here, as shown in FIG. 4, the respective drive voltages V _D1 , V _D2 , V _D3 and V _D4 are peak level P _w1 , peak level P _w2 , peak level P _w3 and peak level P _w4.
Can be expressed as follows.

Drive voltage V _D1 = P _w1 Drive voltage V _D2 = P _w2 -P _w1 Drive voltage V _D3 = P _w3 -P _w2 Drive voltage V _D4 = P _w4 -P _w3 That is, each of the above four emission levels Is the above 4
The drive voltages V _D1 , V _D2 , V _D3 and V _D4 are calculated up to the n-th accumulated sum. For example, the peak level P _w4 may be the drive voltages V _D1 , V _D2 , V _D3 and V
Determined as the sum of _D4 .

Next, the drive units 16, 17, 18 and 19 will be described with reference to FIG. For example, the drive unit 1
6 includes a transistor Tr ₁ , a transistor Tr _2, and a transistor Tr ₃ . The positive signal of the balanced output of the amplifier 12 is supplied to the base of the transistor Tr ₁ , the collector is connected to the cathode of the laser diode LD, the emitter is directly connected to the emitter of the transistor Tr ₂ and the collector of the transistor Tr ₃ . It is connected. The collector of the transistor Tr ₂ is grounded via the load resistance R ₁ , the inverted signal of the balanced output of the amplifier 12 is supplied to the base, and the emitter is directly connected to the emitter of the transistor Tr ₁ as described above. It is connected to the collector of the transistor Tr ₃ . The drive voltage V _D1 from the APC circuit 20 is supplied to the base of Tr ₃ ,
The emitter is connected to V _EE via resistor R ₁₁ . The other drive circuits have the same configuration.

Next, the above drive voltages V _D1 , V _D2 , V _D3
2 and 3 for the APC circuit 20 that outputs V _D4 and V _D4 .
Will be described with reference to. The APC circuit 20 has the drive voltages V _D1 , V _D2 , V _D3 and V which are drive amounts.
_D4 is decided by trial writing.

The APC circuit 20 includes a buffer amplifier 21 to which a laser diode light emission monitor voltage V _M for trial writing is supplied, data from the buffer amplifier 21, and reference voltage values V _ref1 , V _ref2 , V _ref3 and Comparators 22, 23, 24, and 25 for comparing with V _ref4 , and a low-pass filter (hereinafter referred to as LPF) 2 for band-limiting the comparison outputs of the comparators 22, 23, 24, and 25.
6, 27, 28 and 29 and the LPFs 26, 27, 2
A sample / hold (denoted as S / H in the figure) circuit 3 for sampling / holding the filter outputs from 8 and 29 based on the hold signals H ₁ , H ₂ , H ₃ and H ₄ .
It is composed of 0, 31, 32 and 33.

Then, the APC circuit 20 determines the drive voltages V _D1 , V _D2 , V _D3 and V _D4 which are drive amounts by using the sector format as shown in FIG.

First, the sector format is composed of an APC area, a user data area and a buffer area. Of these, the APC area is for each light emission data D
₁ , D ₂ , D ₃ and D ₄ are different and each has a plurality of blocks, in this case, four blocks B ₁ , B ₂ , B ₃ and B ₄ . The block B ₁ applies the APC process only to the emission data D ₁ . The block B ₂ performs APC processing on the emission data D ₁ and D ₂ . The block B ₃ has an AP for the emission data D ₁ , D ₂ and D ₃ .
C processing is performed. The block B ₄ includes the light emission data D ₁ , D ₂ ,
APC treatment is applied to D ₃ and D ₄ .

The APC signal for performing the APC processing is, for example, a fixed signal having an operation duty ratio (Duty ratio) of 50%,
The light emission data D ₁ , D ₂ , D ₃ and D ₄ have the same timing. By setting the frequency longer than the actual light emission pulse interval, the APC monitor and processing circuit can be simplified.

The sampling timing hold signals H ₁ , H ₂ , H ₃ and H ₄ corresponding to each block are converted into light emission data D ₁ , D ₂ , D ₃ and D ₄ by the pulse generation circuit shown in FIG. Created in sync.

That is, the drive unit 16 is used in the area of the block B ₁ , the drive units 16 and 17 are used in the area of the block B ₂ , and the drive units 16 to ₁ are used in the area of the block B _3.
In the area of the block B ₄ , drive units 16 to 19
This causes the laser diode LD to emit light.

Here, the operation of the APC circuit 20 for determining the drive amount from the laser diode light emission monitor voltage V _M at the time of trial writing will be described.

The laser diode emission monitor voltage V _M is
It is amplified by the buffer amplifier 21 and is compared with the comparators 22, 23, 2
4 and 25. In the comparators 22, 23, 24 and 25, the reference values V _ref1 , V _ref2 , V _ref3 and V _ref4 are compared with the emission monitor voltage V _M, and the comparison output is LPF.
26, 27, 28 and 29. LPF26, 2
7, 28 and 29 limit the band of the comparison output.
The filter outputs of the LPFs 26, 27, 28 and 29 are supplied to the S / H circuits 30, 31, 32 and 33 and sampled. The sampling output is determined as drive voltages V _D1 , V _D2 , V _D3 and V _D4 which are drive amounts, and the driving units 16, 17, 18 and 19 of FIG.
Is supplied to.

Here, the reference value V _ref1 corresponds to the peak level P _w1 shown in FIG. The reference value V _ref2 is P _w2 −P
Equivalent to _w1 . V _ref3 corresponds to P _w3 −P _w2 . V
_ref4 corresponds to P _w4 −P _w3 .

Transistor Tr of drive unit 16 in FIG.
₁ turns on when no current flows through the load resistor R ₁ , that is, when the transistor Tr ₂ turns off. Amplifier 12
Supplies the positive signal of the balanced output of the emission data D ₁ to the base of the transistor Tr ₁ and the inverted signal to the base of the transistor Tr ₂ , so that the transistor Tr ₁ is turned on. At this time, the base of the transistor Tr ₃ is
The drive voltage V _D1 from the APC circuit 20 is supplied. Therefore, the transistor Tr ₃ is also turned on. The drive units 17, 18 and 19 operate similarly.

Therefore, in this embodiment, the APC process can be applied to each level even in the recording compensation of the optical disk recording using a plurality of emission levels, and the high speed AP
The C processing is unnecessary and the recording pulse width can be set arbitrarily.

The optical disk recording apparatus according to the present invention is
The present invention is not limited to the above-mentioned embodiment, and for example, recording may be performed on other discs having different diameters. Further, the light emission level is not limited to four. Further, in order to realize higher density recording, a laser generating element that emits a laser beam having a short wavelength, for example, a harmonic generating element such as a second harmonic generating element may be used.

[0035]

The optical disk recording apparatus according to the present invention is an optical disk recording apparatus which emits light from the light emitting means in response to data and records an information signal on the disk-shaped recording medium. A light emission data generating means for generating light emission data, an automatic output control means for outputting n drive voltages by trial writing corresponding to each light emission data, and an n output voltage from the automatic output control means are provided. Since it has n driving means for driving the above-mentioned light emitting means with n light emitting levels, automatic output control processing can be performed for each level by recording compensation for a plurality of light emitting levels, and high-speed automatic output is possible. No control processing is required, and the recording pulse width can be set arbitrarily.

[Brief description of drawings]

FIG. 1 is a block diagram of a laser diode drive circuit of an optical disk recording device according to the present invention.

FIG. 2 is a block diagram of an APC circuit of an optical disc recording device according to the present invention.

FIG. 3 is a diagram showing a relationship between a laser diode light emission monitor voltage and a sector area configuration.

FIG. 4 is a diagram showing laser diode light emission data and a laser diode light emission waveform.

FIG. 5 is a sector format and timing chart.

FIG. 6 is an APC circuit diagram in a conventional optical disc recording device.

FIG. 7 is a laser diode drive circuit diagram in a conventional optical disc recording apparatus.

FIG. 8 is a flowchart showing an operation of a conventional optical disc recording device.

[Explanation of symbols]

 10 laser diode drive circuit 11 pulse generation circuit 12, 13, 14 and 15 amplifier 16, 17, 18 and 19 drive unit

Claims (2)

[Claims] 1. An optical disk recording device for emitting light from a light emitting means according to data to record an information signal on a disk-shaped recording medium, wherein a light emission data generating means generates a plurality of n light emission data according to the data. And automatic output control means for outputting n drive voltages by trial writing corresponding to each light emission data, and the light emission at a plurality of n light emission levels according to the n drive voltages from the automatic output control means. An optical disk recording apparatus comprising a plurality of n driving means for driving the means. 2. The optical disk recording apparatus according to claim 1, wherein each of the n light emission levels is calculated and determined as an accumulated sum of the n drive voltages up to the nth.