JPH05282691A - Tracking error signal generating system - Google Patents

Abstract

PURPOSE:To stably perform a tracking servo by adjusting each gain of two output signals based on two output signal waveforms which are obtained and outputted from a bi-sected photodetector when a tracking servo system is open looped and making tracking error signals by taking a difference of the two signals after the adjustment. CONSTITUTION:A first and a second gain adjustment means 28 and 29 and adjustment input terminals 28a and 29a of the means are provided. Output signals Ia and Ib of two light receiving elements 17a and 17b of a bi-sected photodetector 17 are amplified by the means 28 and 29, respectively. The amplified signals Ia and Ib are inputted to a first differential amplifier 18 and tracking error signals TS are obtained by taking the difference of the two signals. At that time, gain of the means 28 and 29 set the inputs to the terminals 28a and 29a so that the equivalent to an offset of tracking error signals TS becomes zero.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device for optically recording and reproducing information, and relates to a tracking error signal generating system.

[0002]

2. Description of the Related Art An optical disk device needs a tracking servo in order to record or reproduce signals in a concentric or spiral shape on an information medium in a non-contact manner. Various methods have been proposed for generating an error signal for tracking servo (hereinafter referred to as "tracking error signal"), but the laser light from the laser light source is focused on the disk surface and reflected. A method called a push-pull method is known as a method of collecting light on a photodetector having a light receiving surface divided into two in the radial direction and detecting a tracking error signal from a change in light intensity on the photodetector.

Conventionally, there is a push-pull type tracking error signal generating circuit shown in FIG. 8 in an optical disc recording / reproducing apparatus. In FIG. 8, 1 is a pickup, 10 is an optical disk, and 11 is a pickup 1.
Laser light generator provided inside, 12 is a half mirror,
13 is a quarter-wave plate, 14 is a mirror, 15 is an actuator, 16 is an objective lens in the actuator 15, 1
Reference numeral 7 is a two-division photodetector, and 18 is a first differential amplifier.

Next, the operation will be described. The laser light emitted from the laser light generator 11 in the pickup 1 is
The signal recording surface of the disk 10 is irradiated with light through the half mirror 12, the quarter-wave plate 13, the mirror 14 and the objective lens 16 in the actuator. And disk 1
The reflected light from the signal recording surface of 0 again causes the objective lens 16,
Mirror 14, quarter-wave plate 13 and half mirror 1
The two-divided photodetector 17 is irradiated with light via 2.

The two-division photodetector 17 has a photoelectric conversion output TS from two portions 17a and 17b which are vertically divided with respect to the track direction as shown by the arrow A about the optical axis C.
1 and TS2 are output, and a tracking error signal TS is generated by adding these two outputs TS1 and TS2 to the first differential amplifier 18 and taking out the difference (TS1-TS2). ..

The tracking error signal TS is used to drive the objective lens 16 in the actuator 15 via a tracking servo system (not shown) to always perform correct tracking control. That is, when the information pits or the guide grooves forming the signal recording surface of the disk 10 are not displaced from the center of the optical axis, the center of the reflected light passes through the same path as the center of the optical axis, and the two-split photodetector is detected. Since it hits the center of division of 17, the two outputs TS1 and TS2 become the same, and the tracking error signal becomes zero.

On the other hand, when the reflected light deviates from the center of the optical axis C, a difference occurs between the two outputs TS1 and TS2 from the two-divided photodetector 17, so that the first A tracking error signal is output from the differential amplifier 18 of FIG.

As described above, the push-pull method for producing a tracking error signal has a simple circuit configuration, but it may be caused by the deflection of the optical disc or the positional mismatch between the optical disc rotation mechanism and the pickup. There is a problem that the correspondence relationship between the optical disc and the pickup is deviated, and an offset may occur in the tracking error signal.

As a tracking error signal generation method that solves the above problems, for example, Japanese Patent Laid-Open No. 2-28
There is one disclosed in Japanese Patent No. 5526. FIG. 9 is a block diagram showing a conventional example disclosed in the publication. Figure 9
8 shows the same components as those in FIG. 8, 19 is a tracking error signal generation circuit, 20 is an amplifier, 21 is a tracking servo circuit, 22 is an A / D converter, 23 is a CPU, and 24 is a D / A. Converter, 2
5 is an offset adjustment circuit, 26 is a ROM, 27 is a RAM
Is.

Next, the operation will be described. In FIG. 9, a tracking error signal is generated based on the signal output from the light receiving unit, that is, the two-divided detector 17. With the tracking servo loop open, the CPU 23
Detects the maximum value and the minimum value of the tracking error signal by the A / D converter 22, the CPU 23, the D / A converter 24, the ROM 26 and the RAM 27, and calculates the center value of the amplitude of the tracking error signal from the maximum value and the minimum value. Then, the offset value is obtained from this center value. Then, a value according to this offset amount is generated by the offset adjustment circuit 25, and is added in the amplifier 20 to correct the offset amount.

As described above, according to the conventional example disclosed in Japanese Patent Application Laid-Open No. 2-285526, it is possible to cancel the offset amount of tracking.

[Problems to be Solved by the Invention]

However, in this conventional example, since the offset is obtained and corrected after the tracking error signal is generated, both outputs of the two light receiving elements of the two-divided photodetector are missing due to scratches or dirt on the disk surface. Even in such a case, the tracking error signal output does not become 0, the unnecessary DC component remains, and the actuator 15 is driven by a signal irrelevant to the tracking error, which makes the tracking servo unstable. was there.

Further, when the level of the output signal of the two-division photodetector varies due to variations in the type and state of the disk, the amplitude of the resulting tracking error signal also varies, and the tracking servo becomes unstable. There was a problem.

The present invention has been made to solve the above problems, and when the outputs of the two light receiving elements of the two-divided photodetector are both lost due to scratches or dirt on the disk surface, Even when the level of the output signal of the 2-split photodetector varies due to variations in type and state,
An object of the present invention is to provide a tracking error signal generation method capable of stabilizing the tracking servo by suppressing variations in the amplitude of the resulting tracking error signal.

[Means for Solving the Problems]

In the tracking error signal generating method according to the first aspect of the present invention, the two output signals are respectively output based on the two output signal waveforms output from the two-division photodetector obtained when the tracking servo system is open loop. It is characterized by further comprising a gain adjusting means for setting the gain of the amplifier to be amplified.

In the tracking error signal generating method according to the second aspect of the present invention, it is determined whether the used disc is a writable disc, and whether the tracking portion is recorded or not recorded. And a means for amplifying each of the two output signals of the two-division photodetector with a gain preset for the type and state of the disc discriminated by the discrimination means. It is what

[0017]

In the tracking error signal generating method according to the first aspect of the present invention, even if the correspondence between the optical disc and the pickup is deviated due to the deflection of the optical disc or the positional mismatch between the optical disc rotation mechanism and the pickup, the tracking error signal is generated. The offset of the error signal can be canceled, and even if the outputs of the two light receiving elements of the two-divided photodetector are both lost due to scratches or dirt on the disk surface, the tracking error signal output becomes 0 Since unnecessary movements of are suppressed, stable tracking servo can be performed.

In the tracking error signal generating method according to the second aspect of the present invention, even if the level of the output signal of the two-divided photodetector varies due to variations in the type and state of the disc, the amplitude of the resulting tracking error signal is Since the variation is suppressed, stable tracking servo can be performed.

[0019]

【Example】

Example 1. Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the first embodiment. In FIG. 1, the same parts as those in FIG. 8 represent the same parts,
28 and 29 are first and second gain adjusting means, 28a and 2
Reference numeral 9a is an adjustment input terminal of the gain adjusting means 28, 29.

Next, the operation will be described. The output signals Ia and Ib from the two light receiving elements 17a and 17b of the two-divided photodetector 17 are respectively the first and second gain adjusting means 28 and 29.
Are respectively amplified by. The amplified Ia and Ib are input to the first differential amplifier 18, and the tracking error signal TS is obtained by taking the difference between the two. At this time, the respective gains of the first and second gain adjusting means 28 and 29 set the inputs of the adjusting input terminals 28a and 29a so that the offset amount of the tracking error signal TS becomes zero. For example, if a multiplying circuit is used for the first and second gain adjusting means 28 and 29, the adjusted input signal is a multiplier value.

In FIG. 2, in the gain adjusting means 28 and 29 of the first embodiment, when the tracking servo system is in the open loop state, the two light receiving elements 1 of the two-divided photodetector 17 are shown.
It is a figure showing the waveform of the output signals Ia and Ib output from 7a and 17b, and the process until a tracking error signal TS is generated by gain adjustment. As shown in the figure, I
The waveforms a and Ib have almost opposite phases. The shaded area in the figure is Ia, due to scratches and dirt on the disk surface.
It represents a period in which both Ib are missing and are at 0 level.

Gain adjustment is performed by adjusting the difference between Ia and Ib after adjustment,
That is, the amplitude center of the tracking error signal TS is 0
Each gain of Ia and Ib is adjusted so that (= offset is 0). Therefore, unnecessary offset correction is not performed during the shaded period, and the TS level is 0. This is because when the tracking servo system is closed loop and the tracking error signal TS is settled near the 0 level, the tracking error signal TS is held at the 0 level and the tracking servo is stabilized even if the signals Ia and Ib are lost. Means to keep on.

FIG. 3 is a block diagram showing a concrete example of the configuration of the gain adjusting means. The parts having the same reference numerals as those in FIG. 1 are the same, 30 is the first positive peak value detecting means, and 31 is the first. 1
Reciprocal generating means, 32 is a first multiplication circuit, 33 is a second positive peak value detecting means, 34 is a second reciprocal generating means, 3
Reference numeral 5 is a second multiplication circuit. Therefore, the first and second multiplication circuits 32 and 35 correspond to the first and second gain adjusting means 28 and 29 in FIG. 1, respectively.

Next, the operation will be described. The first positive peak value detection means 30 determines the positive peak value Ia1 of the output signal Ia output from 17a of the two light receiving elements of the two-divided photodetector 17 when the tracking servo system is in the open loop state. Detect and hold. The first reciprocal number generating means 31 generates a value (1 / Ia1) which is the reciprocal number of the positive peak value Ia1. The first multiplication circuit 32 performs a calculation for obtaining the product (Ia / Ia1) of the output Ia of the light receiving element 17a and the output (1 / Ia1) of the first reciprocal number generating means 31.

Further, the second positive peak value detecting means 33
Detects and holds the positive peak value Ib1 of the output signal Ib output from 17b of the two light receiving elements of the two-divided photodetector 17 when the tracking servo system is in the open loop state. The second reciprocal generating means 34 generates a value (1 / Ib1) which is the reciprocal of this positive peak value Ib1. The second multiplication circuit 35 performs a calculation for obtaining a product (Ib / Ib1) of the output Ib of the light receiving element 17b and the output (1 / 1b1) of the second reciprocal number generating means 34.

Then, in the first differential amplifier 18,
The difference (Ia / Ia1) between the output (Ia / Ia1) of the first multiplication circuit 32 and the output (Ib / Ib1) of the second multiplication circuit 35-
(Ib / Ib1) is obtained to obtain the tracking error signal TS.

Output signals Ia, Ib of the two-divided photodetector 17 obtained when the tracking servo system is in the open loop state,
Ia and Ib after gain adjustment, and respective positive peak values Ia1 and Ia
The waveforms of b1 and the tracking error signal TS are the same as those shown in FIG.

Example 2. FIG. 4 is a block diagram showing a second embodiment of the present invention. 4, parts having the same reference numerals as those in FIGS. 1 and 3 represent the same parts, 36 is a first negative peak value detecting means, 37 is a first adding circuit, 38 is a second negative peak value. The detecting means 39 is a second adder circuit.

Next, the operation will be described. The first positive peak value detection means 30 determines the positive peak value Ia1 of the output signal Ia output from 17a of the two light receiving elements of the two-divided photodetector 17 when the tracking servo system is in the open loop state. First negative peak value detecting means 36 for detecting and holding
Similarly detects and holds the negative peak value Ia2 of Ia.
The first adder circuit 37 adds Ia1 and Ia2 to obtain Ia1.
The value + Ia2 is output. The first reciprocal generating means 31 is the reciprocal of the output Ia1 + Ia2 of the first adding circuit 37, which is 1
The value of / (Ia1 + Ia2) is output. First multiplication circuit 3
2, the product Ia / (Ia1 + Ia) of the output Ia of the light receiving element 17a and the output 1 / (Ia1 + Ia2) of the first reciprocal number generating means 31.
2) Calculate the value.

The second positive peak value detecting means 33 is a positive peak of the output signal Ib output from 17b of the two light receiving elements of the two-divided photodetector 17 when the tracking servo system is in the open loop state. The value Ib1 is detected and held, and the second negative peak value detection means 38 similarly detects and holds the negative peak value Ib2 of Ib. The second adder circuit 39 uses the above I
The value of Ib1 + Ib2 is output by adding b1 and Ib2. The second reciprocal generating means 34 outputs a value Ib1 + Ib2 which is the reciprocal of the output Ib1 + Ib2 of the second adder circuit 39.
The second multiplication circuit 35 performs a calculation for obtaining the product Ib / (Ib1 + Ib2) of the output Ib of the light receiving element 17b and the output 1 / (Ib1 + Ib2) of the second reciprocal number generating means 34.

Then, in the first differential amplifier 18,
The output Ia / (Ia1 + Ia2) of the first multiplication circuit 32 and the second
Difference Ia from the output Ib / (Ib1 + Ib2) of the multiplication circuit 35 of
/ (Ia1 + Ia2) -Ib / (Ib1 + Ib2) is calculated to obtain the tracking error signal TS.

Output signals Ia, Ib of the two-divided photodetector 17 obtained when the tracking servo system is in the open loop state,
The waveforms of the positive and negative peak values Ia1, Ia2, Ib1, Ib2 and the tracking error signal TS are the same as those shown in FIG.

Example 3. FIG. 5 is a block diagram showing a third embodiment of the present invention. In FIG. 5, the same parts as those in FIG. 3 represent the same parts, and 40 is a first low-pass filter and 41 is a second low-pass filter.

Next, the operation will be described. The first low-pass filter 40 detects the DC component Iam of the output signal Ia output from 17a of the two light receiving elements of the two-divided photodetector 17 when the tracking servo system is in the open loop state. The first reciprocal generating means 31 detects the DC component Iam.
A value of (1 / Iam) that is the reciprocal of is generated. In the first multiplication circuit 32, the product (Ia / Iam) of the output Ia of the light receiving element 17a and the output (1 / Iam) of the first reciprocal number generating means 31.
Is calculated.

The second low-pass filter 41 detects the DC component Ibm of the output signal Ib output from 17b of the two light receiving elements of the two-divided photodetector 17 when the tracking servo system is in the open loop state. To do. The first reciprocal generator 31 is the reciprocal of this DC component Ibm (1 / Ib
m) is generated. The first multiplication circuit 32 performs a calculation for obtaining a product (Ib / Ibm) of the output Ib of the light receiving element 17b and the output (1 / Ibm) of the first reciprocal number generating means 31.

Then, in the first differential amplifier 18,
The difference (Ia / Iam) between the output (Ia / Iam) of the first multiplication circuit 32 and the output (Ib / Ibm) of the second multiplication circuit 35-
(Ib / Ibm) is obtained to obtain the tracking error signal TS.

Output signals Ia, Ib of the two-segment photodetector 17 obtained when the tracking servo system is in the open loop state,
The waveforms of the respective DC components Iam, Ibm and the tracking error signal TS are the same as those shown in FIG.

Example 4. FIG. 6 is a block diagram showing a fourth embodiment of the present invention. 6, parts having the same reference numerals as those in FIG. 4 represent the same parts, 42 is a second differential amplifier, 43
Is a third differential amplifier.

Next, the operation will be described. The first positive peak value detection means 30 determines the positive peak value Ia1 of the output signal Ia output from 17a of the two light receiving elements of the two-divided photodetector 17 when the tracking servo system is in the open loop state. First negative peak value detecting means 36 for detecting and holding
Similarly detects and holds the negative peak value Ia2 of Ia.
The second differential amplifier 42 takes the difference between Ia1 and Ia2 and outputs a value of Ia1-Ia2. The first reciprocal generating means 31 outputs a value of 1 / (Ia1-Ia2) which is the reciprocal of the output Ia1-Ia2 of the second differential amplifier 42. In the first multiplication circuit 32, the product Ia / of the output Ia of the light receiving element 17a and the output 1 / (Ia1-Ia2) of the first reciprocal number generating means 31.
A calculation for obtaining (Ia1-Ia2) is performed.

The second positive peak value detecting means 33 is a positive peak value of the output signal Ib output from 17b of the two light receiving elements of the two-divided photodetector 17 when the tracking servo system is in the open loop state. The second negative peak value detecting means 38 similarly detects and holds Ib1 and the negative peak value Ib2 of Ib. The third differential amplifier 43 is I
The difference between b1 and Ib2 is calculated and the value Ib1-Ib2 is output. The second reciprocal number generating means 34 functions as the third differential amplifier 4
The value Ib1-Ib2 which is the reciprocal of the output Ib1-Ib2 of 3 is output. In the second multiplication circuit 35, the output Ib of the light receiving element 17b and the output 1 / (Ib1-Ib of the second reciprocal number generating means 34)
2) The product Ib / (Ib1-Ib2) with 2) is calculated.

Then, in the first differential amplifier 18,
The output Ia / (Ia1-Ia2) of the first multiplication circuit 32 and the second
Difference Ia from the output Ib / (Ib1-Ib2) of the multiplication circuit 35 of
/ (Ia1-Ia2) -Ib / (Ib1-Ib2) is obtained to obtain the tracking error signal TS.

Output signals Ia, Ib of the two-division photodetector 17 obtained when the tracking servo system is in the open loop state,
The waveforms of the positive and negative peak values Ia1, Ia2, Ib1, Ib2 and the tracking error signal TS are the same as those shown in FIG.

Example 5. FIG. 7 is a block diagram showing a fifth embodiment of the present invention. In FIG. 7, the same reference numerals as those in FIG. 3 represent the same parts, 44 is a third adding circuit, 45 is a disc discriminating means, and 46 is a gain switching means.
Further, portions 28 and 29 surrounded by broken lines in the figure correspond to the first and second gain adjusting means 28 and 29 in FIG. 1, respectively.

Next, the operation will be described. Output signals Ia output from the two light receiving elements of the two-divided photodetector 17,
Ib is added by the third adding circuit 44 to obtain a reproduction signal. Based on this reproduction signal, the disc discriminating means 45 discriminates the disc type and state.

For example, a compact disc (hereinafter,
Of the optical discs based on the "CD" standard, C
D-WO (CD write once = write-once CD) and CD-
If two types of discs, DA (audio discs pressed by a stamper) are used, three types of (1) CD-WO unrecorded (2) CD-WO recorded (3) CD-DA are used for the tracking portion. Therefore, it is necessary to determine the type of CD-WO or CD-DA and the state of unrecorded or recorded.

An example of a concrete discriminating method is as follows: CD-
In WO, a tracking guide groove called a pregroove is formed on the recording surface in advance, and a signal having a constant period called a wobble is recorded in this pregroove. On the other hand, in the CD-DA, the above-mentioned pre-groove does not exist and no wobble is recorded. Therefore, if the reproduced signal contains a wobble component, the CD-
It is WO, and if not included, it can be determined to be CD-DA. Further, it is sufficient to judge whether the pits are formed on the disc surface to judge the unrecorded state or the recorded state, and it corresponds to the presence or absence of a high frequency component in the reproduced signal. If the high frequency component is included, it is recorded, and if it is not included, it is unrecorded.

Based on the result of discriminating the type and state of the disc as described above, the values Ka and Kb selected from the predetermined gain preset by the gain switching means 46 are supplied to the first and second multiplication circuits 32 and 35, respectively. give. Therefore, the outputs of the first and second multiplication circuits 32 and 35 become Ka × Ia and Kb × Ib, respectively, and the difference (Ka × Ia) − (Kb × Ib) between the two is calculated in the first differential amplifier 18. Then, the tracking error signal TS is obtained.

[0048]

As described above, according to the tracking error signal generating method of the first invention shown in the first to fourth embodiments, the tracking servo system outputs from the two-divided photodetector obtained in the open loop. The gain of each of the two output signals is adjusted based on the waveforms of the two output signals, and after the gain adjustment, the difference between the two is taken as the tracking error signal, so that the deflection of the optical disk or the rotation of the optical disk is rotated. Even if the correspondence between the optical disc and the pickup is shifted due to the positional mismatch between the mechanism and the pickup, the offset of the tracking error signal can be canceled, and the split surface is detected due to scratches or dirt on the disc surface. If the outputs of the two light-receiving elements of the detector are both missing, no unnecessary offset correction is performed and the The Nguera signal output as 0, there is an effect that it is possible to perform stable tracking servo.

Further, even if the level of the output signal of the two-division photodetector varies due to the variation in the type and state of the disk, the variation in the amplitude of the tracking error signal obtained as a result is suppressed, so that stable tracking servo is performed. The effect is that you can.

Further, according to the tracking error signal generating method of the second invention shown in the fifth embodiment, a discriminating means for discriminating the kind and the operation mode of the disc is provided, and the disc state discriminated by the discriminating means is set. On the other hand, after the two output signals of the two-division photodetector are amplified by an amplifier having a preset gain, the difference between the two is taken as a tracking error signal. Even if the correspondence between the optical disc and the pickup is deviated due to the positional mismatch between the optical disc rotation mechanism and the pickup, the offset amount of the tracking error signal can be canceled, and the disc surface may be damaged or soiled. If both outputs of the two photodetectors of the split photodetector are missing, An offset correction of the tracking error signal output without 0, there is an effect that it is possible to perform stable tracking servo.

Further, even if the level of the output signal of the two-division photodetector varies due to the variation in the type and state of the disk, the variation in the amplitude of the resulting tracking error signal is suppressed, so that stable tracking servo is performed. The effect is that you can.

[Brief description of drawings]

FIG. 1 is a block diagram showing a tracking error signal generation circuit according to a first embodiment of the first invention.

FIG. 2 is a diagram obtained when the tracking servo system is in an open loop state in the first, second and fourth embodiments of the present invention.
It is a waveform diagram of the output signal of the split photodetector.

FIG. 3 is a block diagram showing a specific example of a gain adjusting means in the first embodiment of the first invention.

FIG. 4 is a block diagram showing a tracking error signal generation circuit according to a second embodiment of the first invention.

FIG. 5 is a block diagram showing a tracking error signal generation circuit according to a third embodiment of the first invention.

FIG. 6 is a block diagram showing a tracking error signal generation circuit according to a fourth embodiment of the first invention.

FIG. 7 is a block diagram showing a tracking error signal generation circuit according to a first embodiment of the second invention.

FIG. 8 is a block diagram showing a first conventional example of a tracking error signal generation circuit in a conventional optical disc device.

FIG. 9 is a block diagram showing a second conventional example of a tracking error signal generation method in a conventional optical disc device.

[Explanation of symbols]

 17 Two-Division Photodetector 17a Photoreceptor 17b Photoreceptor 18 First Differential Amplifier 28 First Gain Adjusting Means 29 Second Gain Adjusting Means 30 First Positive Peak Value Detecting Means 31 First Reciprocal Generating Means 32 1st multiplication circuit 33 2nd positive peak value detection means 34 2nd reciprocal number generation means 35 2nd multiplication circuit 36 1st negative peak value detection means 37 1st addition circuit 38 2nd negative Peak value detecting means 39 second adding circuit 40 first low-pass filter 41 second low-pass filter 42 second differential amplifier 43 third differential amplifier 44 third adding circuit 45 disk discriminating means 46 gain switching means

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[Procedure amendment]

[Submission date] June 5, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

The tracking error signal TS is used to drive the objective lens 16 in the actuator 15 via a tracking servo system (not shown) to always perform correct tracking control. That is, when the information pits or the guide grooves forming the signal recording surface of the disc 10 are not displaced from the center of the optical axis C , the center of the reflected light passes through the same path as the center of the optical axis C and the two-divided light is transmitted. Since it hits the center of division of the detector 17, the two outputs TS1 and TS2 become the same and the tracking error signal becomes zero.

Claims (6)

[Claims] 1. A laser beam from a laser light source is condensed as a minute spot on a disk surface by an objective lens, and the reflected light is collected on a photodetector having a light receiving surface divided into two in the radial direction to perform photodetection. In the optical disc device which detects the tracking error signal from the change of the light intensity on the device and applies the tracking servo, the two outputs output from the above-described two-divided photodetector obtained when the tracking servo system is open loop. A tracking error signal generation method comprising a gain adjusting means for setting a gain of each of two output signals based on a signal waveform. 2. A laser beam from a laser light source is condensed as a minute spot on a disk surface by an objective lens, and the reflected light is collected on a photodetector having a light receiving surface divided into two in the radial direction to perform photodetection. In an optical disc device that detects a tracking error signal from the change in light intensity on the device and applies tracking servo, the tracking servo system outputs two output signals from the photodetector divided into two when the loop is open. On the other hand, a tracking error signal generation method comprising a gain adjusting means for setting a gain so that the respective peak values become equal. 3. A laser beam from a laser light source is condensed as a minute spot on a disk surface by an objective lens, and the reflected light is collected on a photodetector having a light-receiving surface divided into two in the radial direction to perform photodetection. In an optical disc device that detects a tracking error signal from the change in light intensity on the device and applies tracking servo, the tracking servo system outputs two output signals from the photodetector divided into two when the loop is open. On the other hand, gain adjusting means for detecting positive and negative peak values respectively and amplifying each of the two output signals of the photodetector by an amplifier having a gain set by the value of the sum signal of the positive and negative peak values. A tracking error signal generation method characterized by being provided. 4. A laser beam from a laser light source is condensed as a minute spot on a disk surface by an objective lens, and the reflected light is collected on a photodetector having a light receiving surface divided into two in the radial direction to perform photodetection. In an optical disc device that detects a tracking error signal from the change in light intensity on the device and applies tracking servo, the tracking servo system outputs two output signals from the photodetector divided into two when the loop is open. On the other hand, the tracking error is characterized by including gain adjusting means for detecting respective DC components and amplifying each of the two output signals of the photodetector by an amplifier having a gain set by the value of each DC component. Signal generation method. 5. A laser light from a laser light source is condensed as a minute spot on a disk surface by an objective lens, and the reflected light is collected on a photodetector having a light receiving surface divided into two in the radial direction to perform photodetection. In an optical disc device that detects a tracking error signal from the change in light intensity on the device and applies tracking servo, the tracking servo system outputs two output signals from the photodetector divided into two when the loop is open. On the other hand, gain adjusting means for detecting positive and negative peak values, respectively, and amplifying each of the two output signals of the photodetector by an amplifier having a gain set by the value of the difference signal between the positive and negative peak values. A tracking error signal generation method characterized by being provided. 6. A laser beam from a laser light source is condensed as a minute spot on a disk surface by an objective lens, and the reflected light is collected on a photodetector having a light receiving surface divided into two in the radial direction to perform photodetection. Discrimination for disc type and operation mode discrimination based on the state of the output signal output from the photodetector in the optical disc device which detects the tracking error signal from the change of the light intensity on the device and applies the tracking servo. A tracking error signal generation method comprising means.