JP2001266371A - Information recording / reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely correct a change in a servo gain at the time of recording / reproducing with respect to various kinds of information recording media having greatly different light reflectivities and optimum recording laser powers even with a simple device configuration. . SOLUTION: Variable gain amplifiers 2a to 2d amplify light receiving signals output from light receiving elements 1a to 1d, respectively, and an FE signal calculating circuit 4 and a TE signal calculating circuit 5 calculate a servo error signal (FE) from each of the light receiving signals. , TE), and the received light sum signal calculation circuit 3 calculates the amplified received light signal (VA).
To VD), and the set gain calculator 10 generates the variable gain amplifier 2 from the received light sum signal.
The gains a to 2d are calculated and set, and the variable gain amplifiers 7 and 8 and the gain controller 9 automatically control the gain of the servo error signal based on the received light sum signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to information recording of a CD-ROM drive, a CD-R drive, a CD-RW drive, a DVD-ROM drive, a DVD-R drive and a DVD-RAM drive. More particularly, the present invention relates to a servo error signal generation circuit of an optical disk device and an automatic gain control circuit thereof.

[0002]

2. Description of the Related Art In an information recording / reproducing apparatus (referred to as an "optical disc apparatus") for reproducing or recording information on an optical disc, a so-called focus servo mechanism or tracking for irradiating a laser beam to a predetermined position on the optical disc. It has a servo mechanism.

A servo error signal used in such a mechanism is, for example, a track error signal TE in the case of a tracking servo mechanism. A reflected light from an optical disk is received by, for example, a four-divided photodetector, and an arithmetic operation based on each received light amount is performed. The light receiving signal is generated by the processing.

[0004] These servo error signals change the laser power to be irradiated due to the difference in the reflectivity of the optical disk and the difference in various modes such as reproduction, recording, and erasure, so that the output value of the generated light reception signal greatly changes. However, the amplitude of the servo error signal changes greatly.

[0005] The change in the amplitude of the servo error signal causes a change in the servo gain, resulting in a problem that the servo operation becomes unstable or, in the worst case, causes a servo disconnection.

The difference in the reflectivity of the above-mentioned optical discs varies not only with the disc type and the manufacturer, but also with the lot variation, and even with the same disc, it varies with the in-plane variation. Further, the optimum recording laser power at the time of recording differs depending on the optical disc, and the difference in the amplitude of the servo error signal.

Particularly, in the case of an optical disk recording apparatus capable of recording information on a plurality of types of optical disks, for example, a CD
In the case of an apparatus capable of recording on both -R and CD-RW, the above-mentioned difference in the amplitude of the servo error signal becomes particularly remarkable because the reflectivity and the optimum recording power of the different types of optical disks are greatly different.

In order to solve such a problem, servo error signals such as a focus error signal and a track error signal are divided by a total signal of light receiving signals (referred to as a "light receiving total signal"), so that a change in the light receiving signal is obtained. There has been proposed an information recording / reproducing apparatus which corrects a change in servo gain due to the information.

Further, an auto gain control (Auto
o Using a circuit called a gain control (AGC) circuit, the gain is automatically adjusted so that the received light total signal becomes a predetermined voltage, and the same gain is added to each servo error signal to change the disc reflectance and the like. An information recording / reproducing apparatus which always controls the servo gain so as to be maintained at a constant level even when the light receiving signal fluctuates due to the light receiving signal has been put to practical use.

This device will be described here by taking a focus error signal generated by the astigmatism method as an example. Note that other servo error signals may be similarly considered.

FIG. 6 is a block diagram showing an internal configuration of a focus error signal generator of a focus servo mechanism in a conventional information recording / reproducing apparatus. The four-divided light receiving element 100 that receives reflected light from an optical disk (not shown) includes four light receiving elements 100a to 100d, and light receiving signals output from the light receiving elements 100a to 100d are SA to SD, respectively.

A focus error signal calculation circuit (FE signal calculation circuit) 101 generates a focus error signal FE by the astigmatism method based on each of the light receiving signals SA to SD. The received light sum signal calculation circuit 102 is configured to output the received light signals SA to
A light receiving sum signal SUM is generated based on SD.

The variable gain amplifiers 103 and 104 adjust the gain of the focus error signal FE and the gain of the received light sum signal SUM, respectively. The gain control unit 105 outputs to the variable gain amplifier 104 a gain control signal Sgain corresponding to the level of the light reception sum signal SUMn output from the variable gain amplifier 104.

The variable gain amplifier 104 and the gain control section 105 constitute an AGC circuit, and the output value of the light reception sum signal SUM from the variable gain amplifier 104 is maintained at a predetermined level even if the light reception signal fluctuates.

The variable gain amplifier 103 is a variable gain amplifier having substantially the same characteristics as the variable gain amplifier 104.
The focus error signal output from the variable gain amplifier 103 when the above-described gain control signal Sgain is given is FEn. Then, the focus error signal F
E and the light reception sum signal SUM can be generated by the following equations 1 and 2, respectively.

[0016]

FE = (SA + SC)-(SB + SD)

[0017]

## EQU2 ## SUM = (SA + SB + SC + SD)

Further, assuming that the gain given by the gain control signal Sgain is G and the predetermined level of the light-receiving sum signal SUMn output from the variable gain amplifier 104 is k, the variable gain amplifier 103 is calculated based on the following equations (3) and (4). The focus error signal FEn output from the FE signal is the FE signal output from the FE signal calculation circuit 101 and the sum signal SUM.
It can be seen that the signal becomes a normalized signal.

[0019]

SUMn = G · (SA + SB + SC + SD) = k

[0020]

FEn = G · ((SA + SC) − (SB + SD)) = k ((SA + SC) − (SB + SD)) / (SA + SB)
+ SC + SD)

Therefore, if a servo error signal generation circuit such as the focus error signal generation section is used, the servo error signal amplitude is kept constant even if the total received light signal fluctuates due to fluctuations in the reflectivity of the optical disk. It is possible to prevent the fluctuation of the servo gain. This method is widely used because it is more suitable for an integrated circuit than the above-mentioned division circuit.

[0022]

However, in the information recording / reproducing apparatus as described above, an optical disk such as a CD-R disk and a CD-RW disk having greatly different disk reflectivities and optimum recording laser powers are used. When information is reproduced or recorded, the sum of received light signal and the servo error signal fluctuate extremely greatly as described above. There was a problem that the range had to be made very large and gain control became extremely difficult.

Also, since each signal processing circuit handles a signal before AGC in which the signal level fluctuates greatly, it is necessary to increase the dynamic range, and fine adjustment functions can be provided for circuits such as various offset adjustments and balance adjustments. Therefore, there is a problem that a large dynamic range is required, it is difficult to realize gain control, and the circuit scale becomes very large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a servo for recording / reproducing information on a variety of information recording media having greatly different light reflectivities and optimum recording laser powers even with a simple device configuration. It is an object of the present invention to reliably correct a change in gain.

[0025]

In order to achieve the above object, the present invention provides a plurality of light receiving means for receiving reflected light from an information recording medium and outputting the light receiving signal, and a plurality of light receiving means for outputting light receiving signals. A plurality of variable gain amplifying means for amplifying the received light signals, a servo error signal calculating means for calculating a servo error signal based on the light receiving signals respectively amplified by the respective means, and the variable gain amplifying means, respectively. A light receiving sum signal generating means for generating a light receiving sum signal based on the amplified light receiving signal; and a gain of each of the variable gain amplifying means based on the light receiving sum signal generated by the means. A gain calculation setting means for setting each of the means, and a light receiving sum signal generated by the light receiving sum signal generating means. To provide an information recording and reproducing apparatus having an automatic gain control means for automatically controlling the gain of the operational servo error signal by the error signal calculation means.

Also, a plurality of light receiving means for receiving the reflected light from the information recording medium and outputting the light receiving signal, and a plurality of variable gain amplifying means for amplifying the light receiving signal output by each means, respectively. A servo error signal calculating means for calculating a servo error signal based on the light receiving signal amplified by each of the means; and a light receiving means for generating a light receiving sum signal based on the light receiving signal amplified by each of the variable gain amplifying means. Sum signal generation means, peak level detection means for detecting the peak level of the received light total signal generated by the means, and calculate the gain of each of the variable gain amplification means based on the peak level detected by the means, Gain calculation setting means for setting each of the variable gain amplifying means, and light receiving sum signal generating means Based on the made the received sum signal may be an information recording and reproducing apparatus having an automatic gain control means for automatically controlling the gain of the servo error signal calculated by said servo error signal calculating means.

Further, a plurality of light receiving means for receiving the reflected light from the information recording medium and outputting the light receiving signal, and a plurality of first variable gain amplifiers for respectively amplifying the light receiving signal output by each means. Means, a servo error signal calculating means for calculating a servo error signal based on the light receiving signal amplified by each means, and a light receiving sum signal based on the light receiving signal amplified by each of the variable gain amplifying means. Receiving light sum signal generating means, adding means for adding the light receiving signals output by the light receiving means, second variable gain amplifying means for amplifying the light receiving signal added by the means, and the signal amplified by the means. A peak level detecting means for detecting a peak level of the received light signal; and Gain calculating and setting means for calculating respective gains of the first variable gain amplifying means and the second variable gain amplifying means and setting the gains for the first variable gain amplifying means and the second variable gain amplifying means, respectively; The information recording / reproducing apparatus may be provided with an automatic gain control means for automatically controlling the gain of the servo error signal calculated by the servo error signal calculation means based on the light receiving sum signal generated by the generation means.

In the information recording / reproducing apparatus as described above, the gain calculating and setting means may increase or decrease the gain of each of the first variable gain amplifying means by a fixed amount, and
Preferably, means for calculating the gain of the variable gain amplifying means is provided.

Further, in the information recording / reproducing apparatus as described above, the gain calculation setting means is provided with means for calculating the gain at the time of reproduction and the gain at the time of recording of each of the variable gain amplifying means. It is preferable to provide a selection means for selecting the gain at the time of reproduction and the gain at the time of recording based on the recording / reproduction switching signal, and set the gain selected by the means to each of the variable gain amplification means. .

In the information recording / reproducing apparatus as described above, the gain calculating and setting means may include a first gain at the time of reproduction, a first gain at the time of recording, and a second gain at the time of recording of the first variable gain amplifying means. Means for calculating a second gain during reproduction and a second gain during recording of the variable gain amplifying means, wherein the first gain during reproduction and the first gain during recording calculated by the means are provided. And a second selection means for selecting the second gain at the time of reproduction and the second gain at the time of recording based on the recording / reproduction switching signal. The gain selected by the first selector is set for the first variable gain amplifier, and the gain selected by the second selector is set for the second variable gain amplifier. Good.

Further, in the information recording / reproducing apparatus as described above, the gain calculation setting means increases or decreases the first gain of each of the first variable gain amplifying means at the time of reproduction by a fixed amount. The second gain at the time of reproduction of the gain amplifying means is calculated, and the first gain at the time of recording of each of the first variable gain amplifying means is increased or decreased by a fixed amount, and the second variable gain amplifying means at the time of recording is calculated. Preferably, means for calculating the second gain is provided.

In the information recording / reproducing apparatus as described above, the gain calculation setting means detects a peak value of a light reception signal when the objective lens is moved in a direction perpendicular to the information recording medium, and detects the peak value. It is preferable to provide a means for calculating the gain based on

Further, in the information recording / reproducing apparatus as described above, the gain calculation setting means sets the gain of the received light signal when the objective lens is moved in the vertical direction of the information recording medium with the predetermined irradiation light quantity for gain calculation. A peak value is detected, a gain is calculated based on the peak value, and a gain at the time of reproduction and a gain at the time of recording are respectively determined based on the gain, an irradiation light amount for calculation of a predetermined gain, and an irradiation light amount at the time of reproduction and recording. A means for calculating may be provided.

Further, in the information recording / reproducing apparatus as described above, the gain calculation setting means includes means for calculating the gain at the time of reproduction or recording each time the irradiation light quantity at the time of reproduction or recording is changed. It is good to provide.

[0035]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention.
FIG. 3 is a block diagram illustrating a configuration of a focus error signal generation unit and a track error signal generation unit in a focus servo mechanism and a track servo mechanism of the optical disc device according to the embodiment.

The four-divided light receiving element 1 includes four light receiving elements 1
a, 1b, 1c, and 1d, and the information recording medium C
D-ROM, CD-R, CD-RW, DVD-ROM,
Light reflected from optical disks (not shown) such as DVD-R and DVD-RAM is received, and each of the light receiving elements 1a to 1d outputs light receiving signals SA, SB, SC, and SD, respectively.

Variable gain amplifiers 2a, 2b, 2c, 2d
Varies the gain based on an input gain control signal output from a setting gain calculation unit 10 described later, and receives light receiving signals SA and S output from the respective light receiving elements 1a to 1d.
Amplify (or attenuate) B, SC and SD.

Assuming that the gains of the variable gain amplifiers 2a to 2d are input gains G1, each variable gain amplifier 2a
Light-receiving signals VA, VB, VC, VD output from a to 2d
Are generated by using the light receiving signals SA, SB, SC, and SD and performing arithmetic processing based on the following equations 5 to 8, respectively.

[0039]

## EQU5 ## VA = G1 · SA

[0040]

VB = G1 · SB

[0041]

[Expression 7] VC = G1 · SC

[0042]

VD = G1 · SD

The light receiving sum signal calculating circuit 3 receives the light receiving signals VA, VB, V output from the respective variable gain amplifiers 2a to 2d.
A light receiving sum signal SUM obtained by adding C and VD is generated. The received light sum signal SUM is the light receiving signal VA, VB, V
It is generated by arithmetic processing based on the following equation 9 using C and VD.

[0044]

## EQU9 ## SUM = VA + VB + VC + VD

The focus error signal arithmetic circuit 4 receives the light receiving signals VA, V output from the respective variable gain amplifiers 2a to 2d.
A focus error signal FE is generated based on B, VC, and VD. Here, the astigmatism method will be described as an example, so that the focus error signal FE is the light receiving signal VA,
It is generated by an arithmetic process based on the following Expression 10 using VB, VC, and VD.

[0046]

FE = (VA + VC)-(VB + VD)

The track error signal arithmetic circuit 5 receives the light receiving signals VA, V output from the respective variable gain amplifiers 2a to 2d.
A track error signal TE is generated based on B, VC, and VD. Since the push-pull method is described here as an example, the track error signal TE is generated by an arithmetic process based on the following equation 11 and the light receiving signals VA, VB, VC, and VD.

[0048]

## EQU11 ## TE = (VA + VB)-(VC + VD)

The variable gain amplifier 6 amplifies the received light sum signal SUM output from the received light sum signal calculation circuit 3 based on a gain control signal Sgain output from a gain control unit 9 described later, and outputs the received light sum signal SUMn. I do.
Assuming that the amplification factor is G2, the received light sum signal SUMn is
The light reception sum signal SUM is generated by an arithmetic process based on the following equation (12).

[0050]

SUMn = G2 · SUM

The gain control section 9 converts the gain control signal Sgain for controlling the gain of the variable gain amplifier 6 such that the DC component of the light reception sum signal SUMn output from the variable gain amplifier 6 always has a predetermined value. Output to That is, the variable gain amplifier 6 and the gain control unit 9
Constitutes an AGC circuit.

The amplification factor G2 is the sum total of the received light signals SUMn.
If k is a predetermined value for controlling the sum, it is generated by an arithmetic process based on the following Expression 13, and the gain changes with the fluctuation of the light reception total signal SUM.

[0053]

G2 = k / SUM = k / (VA + VB + VC)
+ VD)

The variable gain amplifiers 7 and 8 are almost equivalent to the variable gain amplifier 6, and amplify the focus error signal FE and the track error signal TE based on the gain control signal Sgain output from the gain control section 9 ( The respective output signals are FEn and TEn).

At this time, since the amplification factor is G2, which is equivalent to that of the variable gain amplifier 6, the focus error signal FEn and the track error signal TEn output from the variable gain amplifiers 7 and 8 are expressed by the following equations (14) and (15). , And each servo error signal is automatically gain-controlled.

[0056]

## EQU14 ## FEn = G2.FE = kFE / SUM

[0057]

## EQU15 ## TEn = G2.TE = kTE / SUM

Thus, it can be seen from Equations 14 and 15 that the circuit configuration is equivalent to that of the division circuit. Therefore, the AGC function may be performed by a division circuit instead of the variable gain amplifiers 7 and 8.

The set gain calculator 10 calculates an input gain control signal for setting the gains of the variable gain amplifiers 2a to 2d based on the total light reception signal SUM output from the total light reception signal arithmetic circuit 3, and calculates the input gain control signal. The signal is output to variable gain amplifiers 2a to 2d.

That is, the four-divided light receiving element 1 and the four light receiving elements 1a to 1d receive reflected light from the information recording medium (optical disk) and output a plurality of light receiving signals (SA to SD). Acts as a means.

The variable gain amplifiers 2a to 2d function as a plurality of variable gain amplifying means for amplifying the light receiving signals (SA to SD) output by the respective light receiving means. The FE signal operation circuit 4 and the TE signal operation circuit 5
Based on the light receiving signals (VA to VD) amplified by the respective variable gain amplifying units, the servo error signals (FE,
The function of a servo error signal calculating means for calculating TE) is performed.

The received light sum signal operation circuit 3 outputs the received light signal (VA) amplified by each variable gain amplifying means.
.. VD) to perform the function of a light-receiving sum signal generating means for generating a light-receiving sum signal (SUM).

The set gain calculator 10 calculates the total light reception signal (SUM) generated by the total light reception signal generation means.
Of each variable gain amplifier (variable gain amplifier 2a
2d), and performs the function of gain calculation setting means for setting each of the variable gain amplifying means.

The variable gain amplifiers 7 and 8 and the gain controller 9 control the servo error signal calculating means (FE) based on the light receiving sum signal (SUM) generated by the light receiving sum signal generating means (light receiving sum signal calculating circuit 3). Signal operation circuit 4,
It functions as an automatic gain control means for automatically controlling the gain of the servo error signal (FE, TE) calculated by the TE signal calculation circuit 5).

Next, the automatic gain control processing in the focus error signal generator and the track error signal generator shown in FIG. 1 will be described. The light reception signal fluctuates greatly due to fluctuations in the reflectivity of the disk. The fluctuation factors are roughly classified as follows.

First, the amount of change in the disk reflectivity (this coefficient is referred to as α) includes the disc type, the difference in the reflectivity depending on the manufacturer, the lot variation, the in-plane variation, and the like. Is different between the unrecorded area and the recorded area.

Second, there is a variation component unique to the optical disk device (the coefficient is β). Usually, each parameter of the servo system is not set for each device, but is set according to a predetermined design value.

Therefore, if the device varies from the designed value, the servo gain will fluctuate, which causes unstable servo operation. This includes variations in the conversion efficiency of the light receiving element, variations in the current-voltage conversion coefficient when converting to a light receiving signal (variations in the normal resistance value), and the like.

Third, there is a change in the laser power applied to the optical disk (this coefficient is p). The light receiving signals SA ', SB', S changed by the above-mentioned respective fluctuation factors.
C ′ and SD ′ are obtained by arithmetic processing based on the following equations 16 to 19, respectively.

[0070]

## EQU16 ## SA ′ = αβp · SA

[0071]

[Expression 17] SB ′ = αβp · SB

[0072]

SC ′ = αβp · SC

[0073]

[Equation 19] SD '= αβp · SD

The received light sum signal SUM 'changed by each of the above-mentioned fluctuation factors is obtained by an arithmetic processing based on the following equation (20).

[0075]

SUM ′ = αβp · (SA + SB + SC + S
D) = αβp · SUM

At this time, the light receiving signal VA output from the variable gain amplifier 2a is VA = G1 · SA ′ = G1 · αβ
p · SA. Here, the input gain G1 is the light receiving signal V
A is determined so that A becomes approximately a predetermined value. Further, since the light receiving signals VB to VD also have substantially the same predetermined value as described above, the sum signal SUM does not depend on various fluctuations.

Therefore, each of the subsequent arithmetic circuits and AGC
The dynamic range of the circuit can be reduced, and it can be realized with a simple circuit configuration.

The purpose of setting the input gain G1 is to suppress the dynamic range of the subsequent stage to be low.
The variable gain amplifiers 2a to 2a need not be precisely adjusted to a predetermined value, and may be set within a certain range.
The gain setting resolution and accuracy of d are not so required, and a simple circuit configuration is sufficient.

Further, the variation coefficient β inherent to the apparatus is substantially fixed during the recording / reproducing operation, and the variation α of the disk reflectance is also substantially fixed for each disk, and the in-plane variation is usually not large.

Therefore, even if the input gain G1 is set only once after the insertion of the optical disk, each of the light receiving signals VA to VD does not fluctuate greatly with respect to the recording and reproduction on the optical disk, so that a sufficient effect can be obtained.

Next, the calculation and setting operation of the input gain G1 in the setting gain calculator 10 will be described. The received light sum signal SUM can be obtained by the arithmetic processing based on the following Expression 21 from Expressions 5 to 8 and Expression 9 described above.

[0082]

SUM = G1 · (SA + SB + SC + SD)
= G1 · Ssum

Therefore, the set gain calculating section 10 detects the DC component of the received light sum signal SUM based on the arithmetic processing of the above equation 21, and determines the input gain G1 so that the DC component is within a predetermined range. And each of the variable gain amplifiers 2a to
2d.

According to the focus error signal generating section and the track error signal generating section in the focus servo mechanism and the track servo mechanism of the optical disk apparatus of the first embodiment, the output of each light receiving element of the light receiving means divided into a plurality A plurality of variable gain amplifying means for amplifying the gain, calculating and setting the gain from the total received light signal so that each output thereof becomes a substantially predetermined value, and generating and generating a servo error signal from the output of each variable gain amplifying means. Since automatic gain control is performed, even when recording and reproducing various types of optical disks, the reflectivity of the optical disk and the optimum recording laser power are greatly different, the fluctuation of the servo gain is surely corrected. The AGC circuit and each signal operation circuit can be realized with a simple configuration.

Next, a second embodiment of the present invention will be described. In the case of a recordable optical disk, the unrecorded area and the recorded area may be mixed. The DC component of the received light sum signal is different between the unrecorded area and the recorded area, and the recorded area has a lower level.

As a result, in the automatic gain control processing in the focus error signal generator and the track error signal generator shown in FIG. 1, the calculated value of the input gain may differ depending on the measurement location. Therefore, the focus error signal generation unit and the track error signal generation unit according to the second embodiment solve the above-described problems.

FIG. 2 is a block diagram showing a configuration of a focus error signal generator and a track error signal generator in a focus servo mechanism and a track servo mechanism of an optical disk device according to a second embodiment of the present invention.

The focus error signal generation section and the track error signal generation section include a peak hold circuit 20 for newly detecting the peak value of the received light sum signal SUM in the focus error signal generation section and the track error signal generation section shown in FIG. The set gain calculator 10 calculates the input gain G1 based on the peak hold signal Spk output from the peak hold circuit 20.

Here, the peak hold circuit 20 is used in the case where the polarity of the received light sum signal SUM becomes high when the received light amount is large. If the polarity is reversed, a bottom hold circuit may be used instead.

That is, the four divided light receiving elements and the four light receiving elements 1a to 1d receive reflected light from the information recording medium (optical disk) and output a plurality of light receiving signals (SA to SD). Performs the function of light receiving means.

The variable gain amplifiers 2a to 2d function as a plurality of variable gain amplifying means for amplifying the light receiving signals output by the respective light receiving means. The FE signal operation circuit 4 and the TE signal operation circuit 5 are used for receiving the light receiving signals (VA to V) amplified by the respective variable gain amplifying means.
The function of the servo error signal calculation means for calculating the servo error signal (FE, TE) based on D) is performed.

The received light sum signal operation circuit 3 calculates the received light signal (VA) amplified by each variable gain amplifying means.
.. VD) to perform the function of a light-receiving sum signal generating means for generating a light-receiving sum signal (SUM).

The peak hold circuit 20 generates the total light reception signal (SU) generated by the total light reception signal generation means.
M) functions as a peak level detecting means for detecting the peak level.

The set gain calculating section 10 sets each of the variable gain amplifying sections (variable gain amplifiers 2a to 2a) based on the peak level detected by the peak level detecting section.
It performs the function of the gain calculation setting means for calculating the gain d) and setting it for each variable gain amplifying means (variable gain amplifiers 2a to 2d).

The variable gain amplifiers 7 and 8 and the gain controller 9 control the servo error signal calculating means (SUM) based on the light receiving sum signal (SUM) generated by the light receiving sum signal generating means (light receiving sum signal calculating circuit 3). It functions as an automatic gain control means for automatically controlling the gain of the servo error signal (FE, TE) calculated by the FE signal calculation circuit 4 and the TE signal calculation circuit 5).

In the automatic gain control processing in the focus error signal generation section and the track error signal generation section,
Paying attention to the fact that the peak hold signal Spk of the light reception sum signal SUM has almost no difference between the unrecorded area and the recorded area, the peak hold circuit 20 uses the light reception sum signal Spk.
Since the set gain calculator 10 detects the peak value of the UM and calculates the input gain G1 based on the peak hold signal Spk output from the peak hold circuit 20, it is possible to calculate the same input gain regardless of the measurement location. it can.

According to the focus error signal generating section and the track error signal generating section in the focus servo mechanism and the track servo mechanism of the optical disk apparatus of the second embodiment, the output of each light receiving element of the light receiving means divided into a plurality of parts A plurality of variable gain amplifying means for amplifying the gain, calculating and setting the gain from the peak hold detection signal of the total received light signal so that the output thereof becomes a substantially predetermined value, and setting the servo error signal from the output of the variable gain amplifying means. And automatic gain control.

Therefore, in addition to the same effect as described in the first embodiment, even if the optical disc has a different DC component of the received light sum signal depending on the location where the unrecorded area and the recorded area coexist, the measurement location is not sufficient. The same gain can be calculated independently.

Next, a third embodiment of the present invention will be described. In the focus error signal generation unit and the track error signal generation unit of the second embodiment, in order to accurately detect the peak hold signal Spk of the total light reception signal SUM, the total light reception signal arithmetic circuit 3 and each variable gain amplifier 2a 2d needs to be a broadband circuit that allows a reproduced signal to pass therethrough, and the configuration of a wideband circuit usually involves an increase in circuit scale and an increase in the chip size of an integrated circuit.

On the other hand, since the other servo error signals do not require a wide band signal, the peak hold signal Spk
It is useless to widen the band just for detection. Therefore, the focus error signal generation unit and the track error signal generation unit according to the third embodiment solve the above-described problems.

FIG. 3 is a block diagram showing a configuration of a focus error signal generation section and a track error signal generation section in a focus servo mechanism and a track servo mechanism of an optical disk device according to a third embodiment of the present invention.

The focus error signal generation unit and the track error signal generation unit add the light receiving signals SA to SD to the focus error signal generation unit and the track error signal generation unit shown in FIG. A circuit 30, a variable gain amplifier 31 that amplifies the output of the addition operation circuit 30, and a peak hold circuit 32 that detects the peak value of the output of the variable gain amplifier 31 are provided. Different from the ones.

First, an addition operation circuit 30 having a wide band and a variable gain amplifier 31 are provided. Normally, a circuit equivalent to the addition operation circuit 30 is provided for generating a reproduction signal, so that the circuit may be used as the same, and only a few circuits need to be widened.

Further, the set gain calculating section 10 outputs the peak hold signal Spk output from the peak hold circuit 32.
The input gain to be set in each of the variable gain amplifiers 2a to 2d is calculated based on
The input gain to be set for the variable gain amplifier 31 is calculated,
The second input gain control signal is output and set. Then, the variable gain amplifier 31 varies the gain based on the second input gain control signal from the set gain calculator 10.

That is, the four-divided light receiving element and the four light receiving elements 1a to 1d receive reflected light from the information recording medium (optical disk) and output a plurality of light receiving signals (SA to SD). Performs the function of light receiving means.

The variable gain amplifiers 2a to 2d function as a plurality of first variable gain amplifying means for amplifying the light receiving signal output by each light receiving means. F above
The E signal operation circuit 4 and the TE signal operation circuit 5 output the light-receiving signals (V
A to VD) based on the servo error signal (FE, TE)
Performs the function of a servo error signal calculating means for calculating.

The received light sum signal operation circuit 3 outputs the received light signal (VA) amplified by each variable gain amplifying means.
.. VD) to perform the function of a light-receiving sum signal generating means for generating a light-receiving sum signal (SUM). The addition operation circuit 30 functions as an adding means for adding the light receiving signals output by the respective light receiving means.

The variable gain amplifier 31 functions as a second variable gain amplifying means for amplifying the received light signal added by the adding means. The peak hold circuit 32
It functions as a peak level detecting means for detecting the peak level of the received light signal amplified by the second variable gain amplifying means.

The set gain calculating section 10 controls the first variable gain amplifying means (variable gain amplifiers 2a to 2d) based on the peak level detected by the peak level detecting means.
The gain of each of the first and second variable gain amplifying means (variable gain amplifier 31) is calculated, and the function of the gain calculating and setting means is set for each of the first and second variable gain amplifying means.

The variable gain amplifiers 7 and 8 and the gain control unit 9 control the servo error signal calculating means (FE) based on the light receiving sum signal (SUM) generated by the light receiving sum signal generating means (light receiving sum signal calculating circuit 3). Signal operation circuit 4,
It functions as an automatic gain control means for automatically controlling the gain of the servo error signal (FE, TE) calculated by the TE signal calculation circuit 5).

According to the focus error signal generating section and the track error signal generating section in the focus servo mechanism and the track servo mechanism of the optical disk device of the third embodiment, the output of each light receiving element of the light receiving means divided into a plurality A plurality of first variable gain amplifying means for amplifying the signal, and addition calculating means for adding outputs of the respective light receiving elements of the light receiving means;
A second variable gain amplifying means for amplifying an output of the adding operation means; and a peak hold means for detecting a peak level of the second variable gain amplifying signal. The gain is calculated from the peak hold detection signal. Then, a servo error signal is generated from the output of the variable gain amplifier and automatic gain control is performed.

Therefore, in addition to the same effect as that of the first embodiment, the number of circuits that need to be widened to perform peak hold detection with high accuracy is reduced, and the circuit scale and the chip size of the integrated circuit are further reduced. Can be.

Next, the second input gain control signal is increased or decreased by a fixed amount in accordance with the input gain control signal for setting the gain of the variable gain amplifiers 2a to 2d, or according to the gain of the addition operation circuit 30. It may be.

That is, the set gain calculating section 10
Each first variable gain amplifier (variable gain amplifiers 2a to 2a)
The gain of d) may be increased or decreased by a fixed amount so that the function of the means for calculating the gain of the second variable gain amplifying means (variable gain amplifier 31) may be performed.

In this way, the gain of the second variable gain amplifying means is calculated and set by increasing or decreasing the gain of the first variable gain amplifying means by a fixed amount, so that only one gain can be calculated. In addition, the calculation setting time can be reduced.

Next, in the focus error signal generator and the track error signal generator of the first to third embodiments, the received light sum signal SUM based on the equation (21) will be described as a DC component of the sum signal SUM.

Here, the input gain G1 is equal to the total light reception signal S
UM is calculated based on the value at the time of focusing. At the stage where the input gain G1 is not set properly, the focus servo operation becomes unstable, and the received light sum signal SUM at the time of focusing may be incorrectly detected. Move the lens vertically to the optical disk (up and down)
It is preferable that the input signal GUM be moved to detect the peak value of the received light sum signal SUM and calculate the input gain G1 based on the detected peak value.

When detecting the peak value, the set gain calculating section 10 sets the input gain G1 to a predetermined value (for example, the minimum gain value), and adjusts the input gain so that the received light total signal SUM becomes the predetermined value. calculate. Therefore, if the objective lens is moved up and down again to detect the peak value of the received light sum signal SUM and the input gain G1 is calculated, the calculation can be performed with higher accuracy.

That is, the set gain calculating sections 10 and 4
0 also functions as means for detecting the peak value of the received light signal when the objective lens is moved in the vertical direction of the information recording medium, and calculating the gain based on the peak value.

As described above, the gain calculation setting means detects the peak value of the input signal when the objective lens is moved in the vertical direction of the optical disc, and calculates the gain according to the peak value. Even when the setting is not made, the total signal value at the time of focusing can be detected without performing the focus servo operation, and an accurate gain can be calculated.

Next, a fourth embodiment of the present invention will be described. In general, the laser power applied during reproduction is significantly different from the laser power used during recording. That is, it greatly affects the third light receiving signal variation factor described above.

Since the recording laser power differs depending on the optical disk, it is desirable to set the gain for each disk. That is, switching of the conversion gain in the current-voltage conversion unit of the light reception signal which has been conventionally used may not be sufficient.

Also, the fluctuation of the received light signal due to the change in the laser power at the switching point between the reproduction and the recording changes more rapidly than other factors, so that the servo gain cannot be stabilized by the AGC circuit and the servo operation is unstable. Might be. Therefore, the focus error signal generation unit and the track error signal generation unit according to the fourth embodiment solve the above-described problems.

FIG. 4 is a block diagram showing a configuration of a focus error signal generation section and a track error signal generation section in a focus servo mechanism and a track servo mechanism of an optical disk device according to a fourth embodiment of the present invention.

In the focus error signal generator and the track error signal generator, a set gain calculator 40 is provided in place of the set gain calculator 10 of the focus error signal generator and the track error signal generator shown in FIG. And the set gain calculating section 40 is a light receiving sum signal calculating circuit 3
The variable gain amplifiers 2a to 2d generate a reproduction input gain control signal Gr and a recording input gain control signal Gw for each of the variable gain amplifiers 2a to 2d in accordance with the received light sum signal SUM.

The input gain control signal Gr for reproduction can be obtained by calculating the input gain in the same manner as described above, and the input gain control signal Gw for recording is calculated from the input gain for reproduction as described later.

Further, a selector 41 is newly provided,
The selector 41 switches between the input gain control signal Gr during reproduction and the input gain control signal Gw during recording in accordance with the reproduction / recording switching signal WG, and converts the selected input gain control signal into the input gain of each of the variable gain amplifiers 2a to 2d. Set as

That is, the set gain calculating section 40
The variable gain amplifying means (variable gain amplifiers 2 a to 2 d) also functions as a means for calculating a gain at the time of reproduction and a gain at the time of recording. The function of a selecting means for selecting a gain and a gain at the time of recording based on a recording / reproducing switching signal is performed, and the selected gain is set for each of the variable gain amplifying means.

Since the switching of the input gain by the selector 41 is performed instantaneously, each of the light receiving signals VA to VD does not change abruptly even at the time of switching between recording and reproduction, and the servo gain can be stabilized.

Next, the calculation processing of the recording input gain Gw in the set gain calculation section 40 will be described. The reproduction input gain Gr is calculated in the same manner as the input gain G1 described above.

The recording input gain Gw is determined by
Since UM is proportional to the laser power and other fluctuation factors such as the disk reflectivity do not depend on the laser power, if the laser power at the time of reproduction is Pr and the average laser power at the time of recording is Pw, the following equation (22) is obtained. It can be calculated by an arithmetic process based on the above.

[0132]

Gw = Gr · Pr / Pw

According to the focus error signal generation section and the track error signal generation section in the focus servo mechanism and the track servo mechanism of the optical disk device of the fourth embodiment, the gain calculation and setting means determines the gain at the time of reproduction and the gain at the time of recording. The gain at the time of reproduction and the gain at the time of recording are selected and set in accordance with the recording / reproduction switching signal. The servo gain can be corrected even at the switching of the recording / reproduction, and the stable servo operation can be performed.

In the second embodiment shown in FIG. 2 as well, the same effects as described above can be obtained in the same manner as in FIG.

Next, a fifth embodiment of the present invention will be described. FIG. 5 is a block diagram showing a configuration of a focus error signal generation unit and a track error signal generation unit in a focus servo mechanism and a track servo mechanism of an optical disc device according to a fifth embodiment of the present invention.

In the focus error signal generator and the track error signal generator, the input gain is switched for each of the reproduction and recording modes. The set gains of the focus error signal generator and the track error signal generator shown in FIG. A set gain calculator 40 and selectors 41 and 50 are provided instead of the calculator 10.

The addition operation circuit 30 switches the gain between recording and reproduction. Set gain calculator 40
Calculates the reproduction input gain Gr and the recording input gain Gw of each of the variable gain amplifiers 2a to 2d based on the peak hold signal Spk from the peak hold circuit 32, and calculates the reproduction gain and the recording input gain of the addition arithmetic circuit 30. Based on the gain, a second reproduction input gain Gr2 in which the reproduction input gain Gr is increased or decreased by a fixed amount, and a second recording input gain Gw2 in which the recording input gain Gw is increased or decreased by another fixed amount are calculated.

The selector 41 outputs the reproduction / recording switching signal W
The input gain control signal Gr during reproduction and the input gain control signal Gw during recording are switched in accordance with G, and the selected input gain control signal is applied to each of the variable gain amplifiers 2a to 2d.
Set as the input gain of.

The selector 50 outputs a reproduction / recording switching signal W
G, switching between the second reproduction input gain Gr2 and the second recording input gain Gw2,
Set as a gain of 1.

That is, the set gain calculating section 40 calculates
The first variable gain amplifying means (variable gain amplifiers 2a to 2a)
d) The function of the means for calculating the first gain at the time of reproduction and the first gain at the time of recording, and the second gain at the time of reproduction and the second gain at the time of recording of the second variable gain amplifying means. Also fulfills.

The selector 41 functions as a first selection means for selecting the calculated first gain at the time of reproduction and the first gain at the time of recording based on the recording / reproduction switching signal. , The second gain during reproduction and the second gain during recording.
The function of the second selection means for selecting the gain and the gain based on the recording / reproduction switching signal WG is performed.

The gain selected by the first selector is set for the first variable gain amplifier, and the gain selected by the second selector is set for the second variable gain amplifier. To

Further, the set gain calculating section 40 increases or decreases the first gain of each of the first variable gain amplifying means at the time of reproduction by a fixed amount, and sets the second gain of the second variable gain amplifying means at the time of reproduction. Means for calculating the second gain at the time of recording of the second variable gain amplifying means by increasing or decreasing the first gain at the time of recording of each of the first variable gain amplifying means by a fixed amount. Performs functions.

According to the focus error signal generation section and the track error signal generation section in the focus servo mechanism and the track servo mechanism of the optical disk device of the fifth embodiment, the gain calculation and setting means is configured to set the gain at the time of the first reproduction. And a gain at the time of the first recording, a gain at the time of the second reproduction, and a gain at the time of the second recording, wherein the gain at the time of the first reproduction and the gain at the time of the first recording are calculated. Is selected according to the recording / reproducing switching signal, and is used as the gain of the first variable gain amplifying means. The gain at the time of the second reproducing and the gain at the time of the second recording are selected according to the recording / reproducing switching signal. The output of the second selecting means is the gain of the second variable gain amplifying means.

Therefore, in addition to the effects of the third embodiment,
The servo gain can be corrected even at the switching between recording and reproduction where the light receiving signal greatly and rapidly fluctuates, and a stable servo operation can be performed.

The gain at the time of the second reproduction is equal to the first gain.
Since the gain at the time of reproduction is calculated by increasing or decreasing the fixed amount, and the gain at the time of the second recording is calculated by increasing or decreasing the gain at the time of the first recording by another fixed amount, the gain is calculated. May be used for only one of them, and the calculation setting time can be shortened.

Next, in the focus error signal generation unit and the track error signal generation unit of the fourth and fifth embodiments, the received light sum signal SUM based on the equation (21) will be described as a DC component of the sum signal SUM.

Here, the input gain G1 is equal to the light-receiving sum signal S
UM is calculated based on the value at the time of focusing. When the input gain G1 is not properly set, the focus servo operation becomes unstable, and the received light sum signal SUM at the time of focusing may be incorrectly detected. The objective lens is moved in the vertical direction (up and down) of the optical disk without operation, the peak value of the total light reception signal SUM at that time is detected, and the input gain G1 at the time of reproduction is calculated based on the peak value. .

The input gain at the time of recording is calculated based on the input gain at the time of reproduction, the irradiation light amount at the time of reproduction, and the irradiation light amount at the time of recording.

As described above, when reproducing, the objective lens is moved up and down again to detect the peak value of the total light receiving signal SUM to calculate the input gain G1, and when recording, the input gain G1 is calculated based on the input gain during reproduction. It can be calculated more accurately.

Alternatively, the objective lens is moved in the vertical direction (up and down) of the optical disk without performing the focus servo operation with the irradiation light amount at the time of recording, and the received light total signal SUM at that time is moved.
And the input gain G1 during recording is calculated based on the peak value, and the input gain during reproduction is determined by the input gain during recording, the irradiation light amount during recording, and the irradiation light amount during reproduction. You may make it calculate based on it.

That is, the set gain calculating section 40 detects the peak value of the light receiving signal when the objective lens is moved in the vertical direction of the information recording medium with the predetermined light quantity for calculating the gain, and determines the peak value. A function of calculating a gain based on the gain, an irradiation light amount for calculating a predetermined gain, and an irradiation light amount during reproduction and recording is also performed.

As described above, the peak value of the input signal when the objective lens is moved in the vertical direction of the optical disk is detected by the irradiation light amount at the time of the reproduction, and the reproduction gain calculated according to the peak value is obtained. It is calculated from the input gain at the time, the irradiation light amount at the time of reproduction, and the irradiation light amount at the time of recording, so that the input gain at the time of reproduction can be accurately calculated, and the input gain at the time of recording is calculated without performing irradiation at the recording power. be able to.

Next, in recording on the same optical disk,
When changing the recording laser power, the recording gain may be calculated again based on the above equation (22) according to the recording laser power, and set as the recording input gain.

At the time of reproduction, the irradiation light amount may be changed according to the reproduction speed. In this case, the reproduction gain is calculated again according to the reproduction laser power and set as the reproduction input gain in the same manner as described above. Thus, the reproducing laser power may be changed.

That is, the set gain calculating section 40
Each time the amount of irradiation light at the time of reproduction or recording is changed, the function of means for calculating the gain at the time of reproduction or recording is also performed.

As described above, the gain at the time of recording is calculated every time the irradiation light amount at the time of recording is changed. Therefore, even when the irradiation light amount at the time of recording is frequently changed such as during the OPC operation, a stable servo is obtained. Operation can be performed. Also, a suitable gain can be calculated and set when changing the irradiation light amount at the time of reproduction.

Normally, in a recordable optical disk, recording is performed while sequentially changing the recording laser power in a predetermined test writing area, and an operation of calculating the optimum recording power of the optical disk (called OPC) is performed. . This embodiment is a preferred example during this OPC operation,
A stable servo operation can be performed even during the C operation.

In the above description, the generation of the focus error signal by the astigmatism method and the generation of the track error signal by the push-pull method have been described. However, the generation of the servo error signal by another method is the same as described above. Then, the present invention can be implemented by applying the automatic gain control according to the present invention.

In the above-described embodiment of the present invention,
D-ROM drive, CD-R drive, CD
-RW drive device, DVD-ROM drive device, D
The present invention relates to general recording / reproducing optical disk devices such as a VD-R drive device, and is particularly suitable for an optical disk device capable of handling a plurality of types of optical disks.

[0161]

As described above, according to the information recording / reproducing apparatus of the present invention, it is possible to record information on a variety of information recording media having greatly different light reflectivities, optimum recording laser powers, etc., even with a simple apparatus configuration. Fluctuations in servo gain during reproduction can be reliably corrected.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a focus error signal generation unit and a track error signal generation unit in a focus servo mechanism and a track servo mechanism of an optical disc device according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a focus error signal generation unit and a track error signal generation unit in a focus servo mechanism and a track servo mechanism of the optical disc device according to the second embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a focus error signal generation unit and a track error signal generation unit in a focus servo mechanism and a track servo mechanism of an optical disc device according to a third embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a focus error signal generation unit and a track error signal generation unit in a focus servo mechanism and a track servo mechanism of an optical disc device according to a fourth embodiment of the present invention.

FIG. 5 is a block diagram illustrating a configuration of a focus error signal generation unit and a track error signal generation unit in a focus servo mechanism and a track servo mechanism of an optical disc device according to a fifth embodiment of the present invention.

FIG. 6 is a block diagram showing an internal configuration of a focus error signal generation unit of a focus servo mechanism in a conventional information recording / reproducing apparatus.

[Explanation of symbols]

1,100: four-division light receiving element 1a to 1d, 100a to 100d: light receiving element 2a to 2d, 6 to 8, 31, 103, 104: variable gain amplifier 3, 102: light receiving sum signal operation circuit 4, 101: FE signal Arithmetic circuit 5: TE signal arithmetic circuit 9, 105: gain control unit 10, 40: set gain calculating unit 20, 32: peak hold circuit 30: addition arithmetic circuit 41, 50: selector

Claims (10)

[Claims] 1. A plurality of light receiving means for receiving reflected light from an information recording medium and outputting a light receiving signal thereof, and a plurality of variable gain amplifying means for amplifying the light receiving signal output by each of the means. A servo error signal calculating means for calculating a servo error signal based on the light receiving signal amplified by each of the means; and a light receiving means for generating a light receiving sum signal based on the light receiving signal amplified by each of the variable gain amplifying means. Sum signal generating means, gain calculation setting means for calculating the gain of each of the variable gain amplifying means based on the received light sum signal generated by the means, and setting the gain for each of the variable gain amplifying means; A servo error signal calculated by the servo error signal calculating means based on the received light total signal generated by the total signal generating means; Information recording and reproducing apparatus characterized by comprising an automatic gain control means for automatically controlling the gain. 2. A plurality of light receiving means for receiving the reflected light from the information recording medium and outputting the light receiving signal, and a plurality of variable gain amplifying means for amplifying the light receiving signal output by each means. A servo error signal calculating means for calculating a servo error signal based on the light receiving signal amplified by each of the means; and a light receiving means for generating a light receiving sum signal based on the light receiving signal amplified by each of the variable gain amplifying means. Sum signal generating means, peak level detecting means for detecting the peak level of the received light total signal generated by the means, and calculating the gain of each of the variable gain amplifying means based on the peak level detected by the means, Gain calculation setting means for setting each of the variable gain amplifying means; and An information recording / reproducing apparatus, comprising: automatic gain control means for automatically controlling the gain of the servo error signal calculated by the servo error signal calculation means based on the received light total signal. 3. A plurality of light receiving means for receiving the reflected light from the information recording medium and outputting the received light signal, and a plurality of first variable gain amplifiers for respectively amplifying the received light signal output by the respective means. Means, a servo error signal calculating means for calculating a servo error signal based on the light receiving signal amplified by each means, and a light receiving sum signal based on the light receiving signal amplified by each of the variable gain amplifying means. Receiving light sum signal generating means, adding means for adding the light receiving signals outputted by the light receiving means, second variable gain amplifying means for amplifying the light receiving signal added by the means, Peak level detecting means for detecting a peak level of a received light signal; and the first variable gain based on the peak level detected by the means. Gain calculating and setting means for calculating respective gains of the width means and the second variable gain amplifying means and setting them for the first variable gain amplifying means and the second variable gain amplifying means, respectively; An information recording / reproducing apparatus, comprising: automatic gain control means for automatically controlling the gain of the servo error signal calculated by the servo error signal calculation means based on the generated light receiving sum signal. 4. The information recording / reproducing apparatus according to claim 3, wherein said gain calculation setting means increases or decreases a gain of each of said first variable gain amplifying means by a fixed amount. An information recording / reproducing apparatus, characterized in that a means for calculating a value is provided. 5. The information recording / reproducing apparatus according to claim 1, wherein said gain calculation setting means includes means for calculating a gain at the time of reproduction and a gain at the time of recording of each of said variable gain amplifying means, Selecting means for selecting the gain at the time of reproduction and the gain at the time of recording calculated by the means based on the recording / reproducing switching signal, and setting the gain selected by the means to each of the variable gain amplifying means. An information recording / reproducing apparatus characterized in that: 6. The information recording / reproducing apparatus according to claim 3, wherein the gain calculation setting means includes a first gain at the time of reproduction and a first gain at the time of recording of the first variable gain amplifying means; 2
The second gain during reproduction of the variable gain amplifying means and the second gain during recording
Means for calculating the first gain during reproduction and the first gain during recording calculated by the means based on a recording / reproduction switching signal; And second selecting means for selecting a second gain at the time of recording and a second gain at the time of recording based on the recording / reproducing switching signal, and setting the gain selected by the first selecting means to the first variable gain. An information recording / reproducing apparatus, wherein a gain selected by the second selecting means is set for the second variable gain amplifying means. 7. The information recording / reproducing apparatus according to claim 6, wherein the gain calculation setting means increases or decreases a first gain of each of the first variable gain amplifying means during reproduction by a fixed amount. A second gain at the time of reproduction of the variable gain amplifying means is calculated, and the first gain at the time of recording of each of the first variable gain amplifying means is increased or decreased by a fixed amount, and the second gain at the time of recording of the second variable gain amplifying means An information recording / reproducing apparatus, further comprising: means for calculating the second gain. 8. The information recording / reproducing apparatus according to claim 1, wherein said gain calculation setting means includes a light receiving signal when the objective lens is moved in a direction perpendicular to said information recording medium. An information recording / reproducing apparatus, comprising: means for detecting a peak value and calculating a gain based on the peak value. 9. The information recording / reproducing apparatus according to claim 5, wherein the gain calculation setting means includes an objective lens in a direction perpendicular to the information recording medium with a predetermined gain calculation irradiation light amount. Detects the peak value of the received light signal when the light is moved, calculates the gain based on the peak value, and based on the gain, the irradiation light amount for calculating a predetermined gain, and the irradiation light amount during reproduction and recording. An information recording / reproducing apparatus, comprising: means for calculating respective gains during reproduction and during recording. 10. The information recording / reproducing apparatus according to claim 9, wherein the gain calculation setting means includes means for calculating the gain at the time of reproduction or recording each time the irradiation light amount at the time of reproduction or recording is changed. An information recording / reproducing device, characterized in that it is provided.