JP2003067948A - Optical disk apparatus, method for manufacturing the same, and arithmetic circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a stable tracking servo and seeking characteristics under such a condition being found that the optimum value of a constant K required for the calculation of the tracking error signal and the track cross signal according to a differential push-pull signal by three beams differs slightly, when it is difficult to suppress the crosstalk between a main beam and a sub beam. SOLUTION: In the differential push-pull system by the three beams, with respect to the constant value K for operating and generating the tracking error signal TE or the track cross signal TC, each of a constant Kte for the tracking error signal TE and a constant Ktc for the track cross signal TC is made so as to be capable of being independently set for gain variable amplifiers 49 and 50 by a setting means. Therefore, by the individual setting of respective minimum constants Kte and Ktc, it can properly deal with the case even when it is difficult to suppress the crosstalk between the main beam and the sub beam. Accordingly, the stable tracking servo and the seeking characteristics can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc device using a differential push-pull method using three beams, a method of manufacturing the same, and an arithmetic circuit.

[0002]

2. Description of the Related Art In recent years, various optical disks have been developed, and the most common disk medium can be said to be a CD.
CDs for audio CD-DA, CD-ROM, CD
There are various formats such as -R (Recordable) and CD-RW (ReWritable).

A tracking error detection method used for such a CD is push-push (Push-Pu).
ll) method and DPD (Differential Phase Detection) method mainly used in DVD-ROM drives,
Several methods such as the most common three-beam method have been realized. One of them is a DPP (Diffe
There is a rential push-pull method.

In the three-beam method, a beam from a laser light source is divided by a diffraction grating into a main beam (non-diffracted light) and two sub-beams (first-order diffracted light). In the general three-beam method, P divided into four for receiving the reflected light of the main beam
A total of six PDs are used: D (Photo Detector): A to D and PDs for receiving the reflected light of the sub beam: E and F. The sub-beams E and F are emitted with a shift of about 1/4 of the track pitch (0.4 μm for CD) with respect to the tracking direction. At this time, the track error signal TE is represented by TE = E-F .................................... (1).

On the other hand, in the three-beam DPP method, as shown in Japanese Unexamined Patent Publication No. 8-339556, PD: E, F for receiving a sub-beam is further divided into two, E1, E.
2, FI, F2 (the dividing direction is the tracking direction). At this time, the sub beam is 1/2 from the main beam
Only the tracks are displaced (see FIG. 4 described later).

At this time, the track error signal TE based on the DPP signal is expressed by the equation (2) using the constant K.

TE = {(A + D)-(B + C)}-K * {(E1 + F1)-(E2 + F2)} (2) Further, the track crossing signal (track crossing signal TC) uses a constant K (3 ) Is represented by the formula.

TC = {(A + D) + (B + C)}-K * {(E1 + F1) + (E2 + F2)} (3) This track cross signal TC counts the number of tracks crossed during high-speed seek of the optical pickup. Alternatively, it is used for pulling in the tracking servo after seek by utilizing the phase difference from the track error signal TE.

[0009]

As can be seen from the equations (2) and (3), the constant K value represents the gain ratio between the main beam and the sub-boom. If this value is not appropriate, the track error signal TE is mainly used. And an offset of the track cross signal TC occurs.

Ideally, these T's shown in equations (2) and (3) are
The K values for E and TC should be equal, but for example, in an optical pickup optical system in which the PD positions for the main beam and the sub beams are very close to each other, such as a hologram laser, Crosstalk cannot be ignored.

Further, in the case of the hologram laser, not only the reflected light from the optical disk but also the leaked light due to the internal diffuse reflection and diffraction of the optical system inevitably enters the PD to some extent due to the structure of the optical system. This is called "stray light". It is considered that stray light generally enters the PDs to the same extent if the areas are equal. Therefore, the difference signals such as the track error signal TE and the focus error signal FE cancel out their influences, and are not a serious problem. However, the sum signal such as the track error signal TC has a great influence.

From this point of view, the optimum value for the track cross signal TC may be obtained as the constant K value. In this case, however, the track error signal TE is deviated from the optimum value for the track error signal TE. Will be offset. Such a phenomenon becomes remarkable especially when the objective lens is shifted.

In general, some stamp discs such as CD-ROMs have poor mechanical properties, and the signal amplitude of the track error signal TE is smaller than that of a recording optical disc such as a CD-R. There are many. Even if the signal amplitude and the offset of the track error signal TE can be canceled by increasing the gain of the signal by the operational amplifier and adjusting the offset, this is at the lens center position, and the characteristics when the lens is shifted are There is a risk that it will become extremely bad.

According to the present invention, when it is difficult to suppress the crosstalk between the main beam and the sub-beam, the constants necessary for the calculation of the track error signal TE and the track cross signal TC by the differential push-pull signal by the three beams. K
It is an object of the present invention to provide an optical disk device capable of realizing stable tracking servo and seek characteristics even under such a situation, a manufacturing method thereof, and an arithmetic circuit.

Further, the present invention provides an optical disk device and a method for manufacturing the same, which can mount an optical disk promptly without burdening the firmware in achieving the above object.

Further, in order to achieve the above object, the present invention considers that the track cross signal, which is a sum signal, is easily affected by stray light, and an optical disk device capable of realizing more stable seek characteristics. A manufacturing method is provided.

Further, in order to achieve the above object, the present invention can obtain a stable track error signal TE even when the objective lens is shifted, and can realize more stable tracking servo and seek characteristics. And a method for manufacturing the same.

Further, according to the present invention, the CD having a small signal amplitude of the track error signal TE and causing a problem of the offset of the track error signal TE becomes a problem even under the unusable condition that one value is set as the constant K depending on the system configuration.
-An object of the present invention is to provide an optical disk device that can realize stable tracking servo and seek characteristics even for a read-only optical disk such as a ROM.

[0019]

The invention according to claim 1 is
An optical pickup using a differential push-pull method using three beams of a main beam and two sub beams;
The main beam and the two sub-beams in the beam, and arithmetic means for generating a track error signal TE and a track cross signal TC by a differential push-pull signal based on reflected light components from the optical disc. Push-pull component is MAINpp, sum signal component is MA
INsum, SUB the push-pull components of the two sub-beams
pp, the sum signal component is SUBsum, and the settable constant is K, an optical disk device for performing the calculation represented by TE = MAINpp-K * SUBpp TC = MAINsum-K * SUBsum by the calculating means, The constant K used in the calculating means is the constant Kte for the track error signal TE and the constant Ktc for the track cross signal TC.
As described above, a setting means for individually setting is provided.

Therefore, the constant K value is originally set by switching the gain of the amplifier for calculating and generating the track error signal TE and the track cross signal TC. With respect to this constant K value, the constant K value for the track error signal TE is set. Since the constant Kte and the constant Ktc for the track cross signal TC can be individually set by the setting means, when it is difficult to suppress the crosstalk between the main beam and the sub beams, the differential push-pull with three beams is performed. Even if the value of the constant K necessary for the calculation of the track error signal and the track cross signal by the signal is different, it is possible to appropriately deal with the individual settings, and thus it is possible to realize stable tracking servo and seek characteristics. An optical disk device can be provided.

According to a second aspect of the present invention, in the optical disc device according to the first aspect, the optimum constants Kte and Ktc previously obtained by adjusting each optical disc device at the time of manufacturing the optical disc device are set to the optical disc device. When the apparatus is started up, it has a storage means for storing it so that the setting means can use it.

Therefore, in realizing the invention described in claim 1, due to variations in the optical pickup and the operational amplifier,
Although it is necessary to make adjustments for each optical disk device, the individual constants Kte and Ktc are obtained in advance at the manufacturing stage and saved in a state that can be used at startup, so that the optical disk can be quickly loaded without burdening the firmware. The mount process can be performed.

According to a third aspect of the present invention, in the optical disc device according to the first aspect, the optimum constant Ktc value previously obtained by adjusting each optical disc device at the time of manufacturing the optical disc device is set to the optimum value of the optical disc device. A saving means that can be used by the setting means at the time of start-up, and a Kte adjusting means that performs an adjustment each time the optical disk device is activated and mounts the optical disk to obtain an optimum constant Kte value and provide it to the setting means. And.

Therefore, in realizing the invention described in claim 1, the constant Ktc, which requires a relatively long time for adjustment, is obtained in advance at the manufacturing stage and stored in a state that can be used at the time of start-up. When the apparatus is activated to mount the optical disc, only the constant Kte needs to be adjusted by the Kte adjusting means in a relatively short time.
It is possible to provide an optical disk device that can realize stable tracking servo and seek characteristics in consideration of the manufacturing tact and the mount processing time.

According to a fourth aspect of the present invention, in the optical disk device according to the third aspect, the Kte adjusting means uses the constant Ktc stored in the storing means as an initial value of the constant Kte.

Therefore, the optimum value of the constant Kte can be quickly obtained by using the value of the constant Ktc stored in advance as the initial value of Kte when the disc is mounted.

According to a fifth aspect of the present invention, in the optical disc device according to the first aspect, adjustment is performed every time the optical disc device is activated and the optical disc is mounted to obtain optimum values of constants Kte and Ktc to obtain the optimum values. K to be used for setting means
It has te adjusting means and Ktc adjusting means.

Therefore, at the manufacturing stage of the optical disk device, since it is not necessary to individually obtain the optimum values of the constants Kte and Ktc, the invention according to claim 1 is reduced while reducing the adjustment tact in the manufacturing process. realizable.

According to a sixth aspect of the present invention, in the optical disk device according to the fifth aspect, the Ktc adjusting means adjusts the focus of the optical pickup for adjustment to obtain an optimum value of the constant Ktc for the track cross signal TC. The influence amount obtaining means for obtaining the influence amount of the stray light component of the light source in the OFF state, and the track cross after removing the influence of the stray light component based on the influence amount of the stray light component in the state where the focus servo of the optical pickup is applied. Update adjusting means for adjusting the value of the constant Ktc so that the offset amount of the signal TC is minimized.

Therefore, since the track cross signal TC, which is the sum signal, is easily affected by stray light, the effect of stray light is obtained by the effect amount acquisition means in order to find the optimum constant Ktc for the track cross signal TC. Since the optimum constant Ktc for the track cross signal TC is obtained by the update adjusting means in consideration of the above, the optimum track cross signal TC can be obtained, and stable seek characteristics can be realized.

According to a seventh aspect of the present invention, in the optical disc device according to the fifth aspect, the Ktc adjusting means adjusts to obtain the optimum value of the constant Ktc for the track cross signal TC, and the optical disc is absent. Influence amount acquisition means for obtaining the influence amount of the stray light component of the light source of the optical pickup, and removing the influence of the stray light component based on the influence amount of the stray light component in a state where the focus servo of the optical pickup is applied to the loaded optical disk. In addition, update adjusting means for adjusting the value of the constant Ktc so that the offset amount of the track cross signal TC is minimized.

Therefore, since the track cross signal TC, which is the sum signal, is easily influenced by stray light, the effect of stray light is obtained by the influence amount acquisition means in order to obtain the optimum constant Ktc for the track cross signal TC, and the influence amount is obtained. Since the optimum constant Ktc for the track cross signal TC is obtained by the update adjusting means in consideration of the above, the optimum track cross signal TC can be obtained, and stable seek characteristics can be realized.

The invention according to claim 8 is the invention according to claim 3, 5, or 6.
Alternatively, in the optical disc device described in the paragraph 7, the Kte adjusting means shifts the objective lens in the optical pickup with respect to the optical disc in a radial direction in order to adjust the optimum value of the constant Kte for the track error signal TE. And a Kte value update adjusting unit that adjusts the value of the constant Kte so that the offset amount of the track error signal TE when the objective lens is shifted by a certain amount in the radial direction is minimized.

Therefore, when obtaining the optimum value of the constant Kte for the track error signal TE, it is obtained by the Kte value updating adjusting means under bad conditions in which the objective lens is shifted by a certain amount in the radial direction by the shift control means. Therefore, the track error signal TE can be stably obtained even when the objective lens is shifted, and it is possible to provide an optical disk device capable of realizing stable tracking servo and seek characteristics.

The invention according to claim 9 is characterized in that
An optical pickup using a differential push-pull method with three sub-beams and a track error signal with a differential push-pull signal based on reflected light components from the optical disk of the main beam and the two sub-beams in the three beams TE and a track cross signal TC are generated, and the main beam push-pull component is MAINpp, the sum signal component is MAINsum, the two sub-beam push-pull components are SUBpp, and the sum signal component is SUBsum, An optical disk device for performing a calculation represented by TE = MAINpp−K * SUBpp TC = MAINsum−K * SUBsum, where K is a settable constant, and is an optical disc of the track cross signal TC. An adjustment value initializing means for setting a value Kte that minimizes the offset amount as the value of the constant K, and a disk mount Sometimes, the disc type determining means for measuring the amplitude of the track error signal TE and determining the type of the optical disc based on the magnitude of the amplitude, and the disc type of the optical disc when the amplitude of the track error signal is below a predetermined level are read-only. When it is determined that the disc is a disc, the adjustment value change setting means for setting the value Kte that minimizes the offset amount of the track error signal TE as the value of the constant K is provided.

Therefore, even if Kte and Ktc cannot be individually set as the value of the constant K in the system configuration,
The track error signal TE is small and the track error signal T
CD-ROM where offset of E may be a problem
In the case of a read-only optical disk such as the one described above, stable tracking servo and seek characteristics can be realized by using the value Kte that minimizes the offset amount of the track error signal TE as the K value. In the case of an optical disc in which the disc is not closed, the track cross signal TC in the unrecorded part
Component is small, but in that case, K = Ktc
By doing so, it is possible to realize stable tracking servo and seek characteristics.

According to a tenth aspect of the present invention, there is provided an optical pickup using a differential push-pull method using a three-beam main beam and two sub-beams, and an optical disc having the main beam and the two sub-beams in the three beams. And a calculation means for generating a track error signal TE and a track cross signal TC by a differential push-pull signal based on the reflected light component of the main beam, the main beam push-pull component is MAINpp, the sum signal component is MAINsum, and two When the push-pull component of the sub beam is SUBpp, the sum signal component is SUBsum, and the settable constant is K, the computing means performs a computation represented by TE = MAINpp-K * SUBpp TC = MAINsum-K * SUBsum. In the optical disk device, the value Kte that minimizes the optical offset amount of the track cross signal TC is set to the value of the constant K. The adjustment value initial setting means for setting the track error signal TE, the disk type determining means for measuring the amplitude of the track error signal TE when the disk is mounted, and determining the type of the optical disk based on the magnitude of the amplitude, and the amplitude of the track error signal. Is less than a predetermined level and it is determined that the type of the optical disc is a read-only disc, a value Kte that minimizes the offset amount of the track error signal TE is calculated, and the average value of the Kte and the Ktc is calculated as the constant K. Adjustment value change setting means for setting as the value of.

Therefore, it is basically the same as that of the invention described in claim 9, and it is basically set to K = Ktc as the constant K, but the track error signal TE is small and the offset of the track error signal TE causes a problem. CD that can become
-In the case of a read-only optical disk such as a ROM, by using the average value of Kte and Ktc as the K value, stable tracking servo and seek characteristics can be realized.

The invention according to claim 11 is the invention according to claim 9 or 1.
0 in the optical disk device, the adjustment value change setting means includes shift control means for shifting an objective lens in the optical pickup with respect to the optical disk in a radial direction, and the shift control means when the objective lens is shifted by a certain amount in the radial direction. Kte value update adjusting means for adjusting the Kte value so that the offset amount of the track error signal TE is minimized.

Therefore, when obtaining the optimum value of the constant Kte for the track error signal TE, the Kte value update adjusting means is used under the bad condition that the objective lens is shifted by a certain amount in the radial direction by the shift control means. Therefore, the track error signal TE can be stably obtained even when the objective lens is shifted, and it is possible to provide an optical disk device capable of realizing stable tracking servo and seek characteristics.

According to a twelfth aspect of the present invention, in the optical disc device according to any one of the first to eleventh aspects, a hologram laser is used as a light source in the optical pickup.

Therefore, the action and effect of the optical disk device according to claims 7 to 17 are effectively exhibited, especially when a hologram laser in which crosstalk related to the track error signal TE and the track cross signal TC is difficult to avoid. To be done.

According to a thirteenth aspect of the invention, the main beam and two sub-beams are connected to the output side of an optical pickup using a three-beam differential push-pull system, and the main beam and two of the three beams are connected. The differential push-pull signal based on the reflected light component from the optical disc with the sub-beam is a track error signal TE, the track crossing signal is a track cross signal TC, the push-pull component of the main beam is MAINpp, the sum signal component is MAINsum, and When SUBpp is the push-pull component of the sub-beam, SUBsum is the sum signal component, and K is a settable constant, it is an arithmetic circuit for performing an operation represented by TE = MAINpp-K * SUBpp TC = MAINsum-K * SUBsum. , The constant K is individually set as the constant Kte for the track error signal TE and the constant Ktc for the track cross signal TC. It has a variable gain amplifier for TE and a variable gain amplifier for TC that are each fixed.

Therefore, the constant K value is originally set by switching the gain of the amplifier for calculating and generating the track error signal TE and the track cross signal TC. With respect to this constant K value, the constant K value for the track error signal TE is set. Since the variable gain amplifier for TE and the variable gain amplifier for TC, which are individually set as the constant Kte and the constant Ktc for the track cross signal TC, are provided, when it is difficult to suppress the crosstalk between the main beam and the sub-beam, 3 Even if the value of the constant K required for the calculation of the track error signal and the track cross signal by the differential push-pull signal by the beam is different, by mounting the calculation circuit, it is possible to appropriately deal with each by individual setting. I can, so
An optical disk device that can realize stable tracking servo and seek characteristics can be provided.

According to a fourteenth aspect of the invention, the main beam and two sub beams are connected to the output side of an optical pickup using a three-beam differential push-pull system, and the main beam and two of the three beams are connected. The differential push-pull signal based on the reflected light component from the optical disc with the sub-beam is a track error signal TE, the track crossing signal is a track cross signal TC, the push-pull component of the main beam is MAINpp, the sum signal component is MAINsum, and When SUBpp is the push-pull component of the sub-beam, SUBsum is the sum signal component, and K is a settable constant, it is an arithmetic circuit for performing an operation represented by TE = MAINpp-K * SUBpp TC = MAINsum-K * SUBsum. , The constant K is individually set as the constant Kte for the track error signal TE and the constant Ktc for the track cross signal TC. Then, the operation represented by TE = MAINpp-Kte * SUBpp TC = MAINsum-Ktc * SUBsum is performed.

Therefore, the constant K value is originally set by switching the gain of the amplifier for calculating and generating the track error signal TE and the track cross signal TC. With respect to this constant K value, the constant K value for the track error signal TE is set. Since the constant Kte and the constant Ktc for the track cross signal TC are TE = MAINpp-Kte * SUBpp TC = MAINsum-Ktc * SUBsum, the crosstalk between the main beam and the sub-beam can be suppressed. In the case of difficulty, even if the value of the constant K necessary for the calculation of the track error signal and the track cross signal by the differential push-pull signal by the three beams is different, by mounting the calculation circuit, each can be set individually. An optical disc that can be dealt with appropriately and thus can achieve stable tracking servo and seek characteristics. It is possible to provide a device.

According to a fifteenth aspect of the present invention, there is provided an optical pickup using a differential push-pull method using a three-beam main beam and two sub-beams, and an optical disc having the main beam and the two sub-beams in the three beams. And a calculation means for generating a track error signal TE and a track cross signal TC by a differential push-pull signal based on the reflected light component of the main beam, the main beam push-pull component is MAINpp, the sum signal component is MAINsum, and two When the push-pull component of the sub beam is SUBpp, the sum signal component is SUBsum, and the settable constant is K, the computing means performs a computation represented by TE = MAINpp-K * SUBpp TC = MAINsum-K * SUBsum. A method of manufacturing an optical disk device, wherein adjustment is performed for each optical disk device when manufacturing the optical disk device, and the calculation is performed. An obtaining step of obtaining the optimum values of the constant K used in each stage as the constant Kte for the track error signal TE and the constant Ktc for the track cross signal TC, and the calculating means for calculating the obtained values of the constants Kte and Ktc. And a setting step of setting for.

Therefore, the constant K value is originally set by switching the gain of the amplifier for calculating and generating the track error signal TE and the track cross signal TC, but this constant K value is previously set at the manufacturing stage of the optical disk device. Since the values can be individually set as the constant Kte for the track error signal TE and the constant Ktc for the track cross signal TC, when it is difficult to suppress the crosstalk between the main beam and the sub-beams, three beams are used. Even if the value of the constant K necessary for the calculation of the track error signal and the track cross signal by the differential push-pull signal is different, it can be dealt with appropriately by the individual setting, so that stable tracking servo and seek can be performed. It is possible to provide a method for manufacturing an optical disc device that can realize the characteristics.

According to a sixteenth aspect of the present invention, there is provided an optical pickup using a differential push-pull method using three beams of a main beam and two sub beams, and an optical disc of the main beam and the two sub beams in the three beams. And a calculation means for generating a track error signal TE and a track cross signal TC by a differential push-pull signal based on the reflected light component of the main beam, the main beam push-pull component is MAINpp, the sum signal component is MAINsum, and two When the push-pull component of the sub beam is SUBpp, the sum signal component is SUBsum, and the settable constant is K, the computing means performs a computation represented by TE = MAINpp-K * SUBpp TC = MAINsum-K * SUBsum. A method of manufacturing an optical disk device, wherein adjustment is performed for each optical disk device when manufacturing the optical disk device, and the calculation is performed. An obtaining step of obtaining an optimum value of the constant K used in each stage as a constant Kte for the track error signal TE and a constant Ktc for the track cross signal TC, and the obtained values of the constants Kte, Ktc for the optical disk device. And a saving step of saving the file so that it can be used when starting up.

Therefore, it is necessary to make adjustments for each optical disk device due to variations in the optical pickup and the operational amplifier, but the individual constants Kte and Ktc are obtained in advance at the manufacturing stage and stored in a state that can be used at startup. By setting it, the mounting process of the optical disk can be promptly performed without burdening the firmware.

According to a seventeenth aspect of the present invention, there is provided an optical pickup using a differential push-pull method using three beams of a main beam and two sub beams, and an optical disc of the main beam and the two sub beams in the three beams. And a calculation means for generating a track error signal TE and a track cross signal TC by a differential push-pull signal based on the reflected light component of the main beam, the main beam push-pull component is MAINpp, the sum signal component is MAINsum, and two When the push-pull component of the sub beam is SUBpp, the sum signal component is SUBsum, and the settable constant is K, the computing means performs a computation represented by TE = MAINpp-K * SUBpp TC = MAINsum-K * SUBsum. A method of manufacturing an optical disk device, wherein adjustment is performed for each optical disk device when manufacturing the optical disk device, and the calculation is performed. An obtaining step of obtaining an optimum value of the constant Ktc as the constant Kte for the track error signal TE and the constant Ktc for the track cross signal TC using the constant K used in each stage, and the obtained value of the constant Ktc for the optical disc device. And a saving step of saving the file so that it can be used at startup.

Therefore, although the same as the sixteenth aspect of the present invention, the constant Ktc, which requires a relatively long time for adjustment, is obtained in advance at the manufacturing stage and stored in a state where it can be used at the time of startup, so that the optical disc When the apparatus is started up and the optical disk is mounted, it is only necessary to adjust the constant Kte, which requires a comparatively short time. Considering the manufacturing tact and the mounting processing time, stable tracking servo and seek characteristics can be obtained. It is possible to provide a method for manufacturing an optical disk device capable of realizing the above.

The invention described in claim 18 is the method for manufacturing an optical disk device according to claim 15 or 16, wherein the constant K for the track error signal TE is obtained in the obtaining step.
In the adjustment for obtaining the optimum value of te, the value of the constant Kte is adjusted so that the offset amount of the track error signal TE becomes minimum when the objective lens in the optical pickup with respect to the optical disc is shifted in the radial direction by a certain amount. I decided to do it.

Therefore, when obtaining the optimum value of the constant Kte for the track error signal TE, the objective lens is shifted under a bad condition in which the objective lens is shifted by a certain amount in the radial direction. However, the track error signal TE can be stably obtained, and it is possible to provide a method for manufacturing an optical disk device that can realize stable tracking servo and seek characteristics.

According to a nineteenth aspect of the present invention, in the method of manufacturing an optical disk device according to any one of the fifteenth to eighteenth aspects, the track cross signal T is obtained in the obtaining step.
The adjustment for obtaining the optimum value of the constant Ktc for C includes the step of obtaining the influence amount of the stray light component of the light source in the focus-off state of the optical pickup, and the influence of the stray light component in the state where the focus servo of the optical pickup is applied. The step of adjusting the value of the constant Ktc so as to minimize the offset amount of the track cross signal after removing the influence of the stray light component based on the amount.

Therefore, since the track cross signal TC, which is the sum signal, is easily affected by stray light, the effect of stray light is obtained in order to obtain the optimum constant Ktc for the track cross signal TC, and the amount of the influence is taken into consideration in the track. Since the optimum constant Ktc for the cross signal TC is obtained, the optimum track cross signal TC can be obtained and stable seek characteristics can be realized.

According to a twentieth aspect of the present invention, in the method of manufacturing an optical disk device according to any one of the fifteenth to eighteenth aspects, the track cross signal T is obtained in the obtaining step.
The adjustment for obtaining the optimum value of the constant Ktc for C is performed in the step of obtaining the influence amount of the stray light component of the light source of the optical pickup without the optical disc and in the state where the optical disc is loaded and the focus servo of the optical pickup is applied. The step of adjusting the value of the constant Ktc so as to minimize the offset amount of the track cross signal after removing the influence of the stray light component based on the influence amount of the stray light component.

Therefore, since the track cross signal TC, which is the sum signal, is easily affected by stray light, the effect of stray light is obtained in order to find the optimum constant Ktc for the track cross signal TC, and the amount of the influence is taken into consideration in the track. Since the optimum constant Ktc for the cross signal TC is obtained, the optimum track cross signal TC can be obtained and stable seek characteristics can be realized.

[0059]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment of the present invention.
Through 8 will be described. This embodiment is a CD
-In addition to a read-only disc such as a ROM, an application example to an optical disc device for an optical disc such as a CD-R or a CD-RW capable of recording information is shown, and a manufacturing method thereof is also included.

FIG. 1 shows an optical disk device according to this embodiment.
In particular, it is a block diagram showing a configuration example of the drive system.
First, a spindle motor 2 for rotating the optical disc 1 is provided. The spindle motor 2 is controlled to be of a constant linear velocity (CLV) system or a constant rotation speed (CAV) system under the control of the motor driver 3 and the servo means 4.

The optical pickup 5 for irradiating the optical disc 1 with laser light will be described in detail later, but the wavelength 7
The light source includes an 80 nm semiconductor laser, an optical system such as an objective lens, a focus actuator, a track actuator, a light receiving element such as a PD, a position sensor, and the like. The laser beam emitted from the semiconductor laser is focused on the recording surface of the optical disc 1 by the objective lens,
Each signal from the light receiving element that receives the reflected light from the optical disc 1 is arithmetically processed in the RF amplifier 6, and a read signal (RF
Signal, HF signal, etc.), focus error signal F
Signals such as E and the track error signal TE are produced.
Information recorded on the optical disk 1 is reproduced or recorded on the optical disk 1 by controlling the actuator by the servo means 4 such as the focus servo and the track servo based on these signals.

Here, as a method of detecting the focus error signal FE, an astigmatism method or a knife edge method is generally used, and the astigmatism method is used in the present embodiment. Further, as a method of detecting the track error signal TE, a push-pull method or a DPD (Differ) method is used.
Although it is realized by several methods such as the critical phase detection method and the three-beam method, in the present embodiment, three methods are used.
DPP ((Differential Push-Pul
l) method is used. These detection methods will be described later.

In the case of reproducing CD data, the optical pickup 5
The reproduction signal obtained in step 2 is arithmetically amplified by the RF amplifier 6 and binarized (digitized), and then input to the CD decoder 7 and EFM (Eight to Fourteen Modulation) demodulated. After that, interleave and error correction processing is performed on the EFM demodulated data, and the data after the interleave and error correction processing is input to the CD-ROM decoder 8 to perform error correction for improving the reliability of the data. Processing is performed.

Thereafter, the data processed by the CD-ROM decoder 8 is temporarily stored in the buffer RAM 10 by the buffer manager 9, and when the data is prepared as sector data, the host interface 1 such as ATAPI or SCSI is used.
1 to the host computer (not shown) at once.

In the case of music data, the output data from the CD decoder 7 is input to the D / A converter 18 and an analog audio signal is taken out.

On the other hand, when recording CD data, ATAP
The data sent from the host computer side via the host interface 11 such as I or SCSI is temporarily stored in the buffer RAM 10 by the buffer manager 9, and when a certain amount of data is stored in the buffer RAM 10, the CD-ROM encoder 13, the CD encoder Writing is started via 14 and the LD driver 15. Here, prior to this writing, the spot of the laser beam must be positioned at the writing start position.
This writing start position is obtained from the wobble signal previously recorded on the optical disc 1 due to the meandering of the track.
This wobble signal has ATIP (Absolute Time In)
It includes absolute time information called Pregroove),
The ATIP decoder 12 retrieves this information. Further, the sync signal generated by the ATIP decoder 12 is input to the CD encoder 14 to enable writing of data at an accurate position. The push-pull type optical pickup 5 is required to detect the wobble signal.

Data in the buffer RAM 10 is subjected to EFM modulation after addition of error correction code and interleaving, and is recorded on the optical disc 1 via the LD driver 15 and the optical pickup 5.

In such an optical desk device, a system controller 1 having a microcomputer configuration including a CPU, a ROM and a RAM for controlling the operations of the respective parts as described above and executing the functions of the respective means described later.
6 is provided. A memory 17 is connected to the system controller 16.

In the structure shown in FIG. 1, the RF amplifier 6 as an arithmetic circuit and the LD driver 15 are formed as an analog chip in an LSI, and the servo means 4, the CD decoder 7, the CD-ROM decoder 8, the buffer manager 9,
ATIP decoder 12, CD-ROM encoder 13,
The CD encoder 14 and the system controller 16 are configured as an LSI as a digital chip.

Next, a basic configuration example of the optical pickup 5 will be described with reference to FIG. The optical pickup 5 used in this embodiment has a semiconductor laser unit 21 in which a light source and a light receiving element are integrated, a coupling lens 22 for collimating a laser beam emitted from the semiconductor laser unit 21, and a parallelization. Optical disk 1 with laser beam
And a wave plate 24 for deflecting the light to the side.
And an objective lens 25 for focusing the laser beam on the recording surface of the optical disc 1. Since the semiconductor laser unit 21 is also integrated with the light receiving element, the optical disk 1
The reflected light reflected by is returned to the inside of the semiconductor laser unit 21 via the objective lens 25 and the like. Further, a front light receiving element 26 for monitoring the light quantity of the semiconductor laser in the semiconductor laser unit 21 is also provided.

FIG. 3 shows an example of the structure of the semiconductor laser unit 21. The semiconductor laser unit 21 is configured to use a hologram laser for separating emitted light and return light (reflected light). That is, the semiconductor laser unit 21 has a semiconductor laser 32 as a light source and a light receiving element 33 which are positioned and incorporated in a unit housing 31 at a predetermined position, and the light receiving element 33 is provided at the emission side position of the semiconductor laser 32.
A hologram element 34 is attached to a position on the incident side of the return light with respect to. The laser beam emitted from the semiconductor laser 32 is divided into three beams of a main beam and two sub beams by a diffraction grating (not shown),
The optical disk 1 is irradiated with the optical system shown in FIG.
The reflected light components from the optical disc 1 relating to these three beams are diffracted by the hologram element 34,
The incident light (light emitted from the semiconductor laser 32) is separated and focused on the light receiving element 33.

Referring to FIG. 4, the light receiving element 33 includes four divided light receiving areas A, B, C and D for receiving the reflected light component of the main beam M, and one sub beam S.
Light receiving areas E1 and E2 divided into two in the tracking direction for receiving the reflected light component regarding 1 and light receiving areas F1 and F2 divided into two in the tracking direction for receiving the reflected light component regarding the other sub-beam S2. have.

The relationship between the main beam M, the sub-beams S1 and S2, the calculation of the track error signal TE, etc. will now be described with reference to FIG. First, the two sub-beams S1 and S2 are arranged so as to be offset from the main beam M by 1/2 track. The reproduction signal RF is calculated and generated as a sum signal of RF = A + B + C + D (4) based on the amount of light received in the four-divided areas A, B, C, and D for the main beam M. .

The focus error signal FE is obtained by using the amount of light received in the four divided areas A, B, C and D for the main beam M.
By the astigmatism method, FE = (A + C)-(B + D) is calculated and generated as (5).

The track error signal TE is a differential push-pull signal obtained by taking the difference between the push-pull of the main beam M and the push-pulls of the sub-beams S1 and S2. By using such a differential push-pull signal, the offset between the main beam M and the sub-beams S1 and S2 is canceled, so that there is an advantage that the characteristics with respect to the disc tilt and the lens shift are strong. Also, since it is basically a push-pull signal, the above-mentioned ATI
The wobble signal for P can also be detected and can be used as a recording drive.

The arithmetic expression for generating the track error signal TE is such that the push-pull component of the main beam M is MAINpp,
Let SUM be the sum signal component, SUBpp be the push-pull component of the two sub-beams S1 and S2, SUBsum be the sum signal component, and K be a settable constant. TE = MAINpp-K * SUBpp …………………………… ... (6) Referring to the example shown in FIG. 4, TE = {(A + D)-(B + C)}-K * {(E1 + F1)-(E2 + F2)} (7).

On the other hand, the track crossing signal (track crossing signal) TC which is maximum on the track and minimum at the center between the tracks is represented by TC = MAINsum-K * SUBsum ...................................... (8) Be done. Referring to the example shown in FIG. 4, TC = {(A + D) + (B + C)}-K * {(E1 + F1) + (E2 + F2)} (9). This track cross signal TC counts the number of tock straddles during the high speed seek of the optical pickup 5,
Utilizing the feature that the phase difference with the track error signal TE is 90 °, it is used for pulling in the tracking servo during seek.

As described above, the value of the constant K in these arithmetic expressions represents the gain ratio between the main beam M and the sub-beams S1 and S2. If this K value is not appropriate, the track error signal TE or An offset occurs in the track cross signal TC. Here, ideally, the optimum values of the constant K in the track error signal TE and the track cross signal TC are equal (common). However, in reality, in the configuration of the semiconductor laser unit 21 using the hologram laser shown in FIG. 3, the light receiving areas A, B, C, D for the main beam M and the light receiving areas E1, for the sub beams S1, S2 are provided. In an optical system configuration in which E2, F1 and F2 are arranged very close to each other, crosstalk between these light receiving regions cannot be completely removed. As a result, the track error signal TE and the track cross signal TC
There is a problem that the optimum value of the constant K is slightly different between and.

Therefore, in the present embodiment,
The constant K in the equations (7) and (9) used in the calculation of the RF amplifier 6
Can be individually set as the constant Kte for the track error signal TE and the constant Ktc for the track cross signal TC. That is, the value of the constant K is set by switching the gain of the amplifier that calculates the track error signal TE and the track cross signal TC. In the present embodiment, however, the TE system and the TC system are related to the value of the constant K. It is possible to set different values Kte and Ktc respectively. Expressed as an arithmetic expression, TE = MAINpp-Kte * SUBpp = {(A + D)-(B + C)}-Kte * {(E1 + F1)-(E2 + F2)} (10) TC = MAINsum-Ktc * SUBsum = {(A + D ) + (B + C)}-Ktc * {(E1 + F1) + (E2 + F2)} ... (11).

Therefore, in the RF amplifier 6 having the LSI chip configuration of the present embodiment, the part relating to the calculation of the track error signal TE and the track cross signal TC is the above-mentioned arithmetic expression.
In order to realize (10) and (11), it is configured as shown in FIG. The reproduction signal RF and the focus error signal FE will be omitted.

First, (A + D), (B + C), (E1 + F)
1) and (E2 + F2) are respectively provided with addition amplifiers 41 to 44 for performing addition processing.
{(A + D)-(B + C)} based on the calculation results of 1 to 44,
{(A + D) + (B + C)}, {(E1 + F1) − (E2 + F
2)}, {(E1 + F1) + (E2 + F2)} are provided for the operational amplifiers 45 to 48. And
On the output side of the operational amplifier 47, a TE gain variable amplifier 49 whose gain is set to Kte is provided.
On the output side of 8, a TC gain variable amplifier 60 whose gain is set to Ktc is provided. Further, an operational amplifier 61 that finally executes the arithmetic expression (10) is provided on the output side of the TE gain variable amplifier 49 and the output side of the operational amplifier 45. Similarly, the output of the TC gain variable amplifier 60 is provided. The operation formula (1
An operational amplifier 62 that executes 1) is provided.

Here, the TE gain variable amplifier 49 and the TC gain variable amplifier 60 have their gain values, and therefore constants Kte and K, determined by a mechanical method such as a volume resistance.
Although the values of tc may be set respectively, in the present embodiment, the RF amplifier 6 itself is configured as an arithmetic LSI amplifier, and the gain values, and accordingly the values of the constants Kte and Ktc are set by the system controller 16. It is configured so that it can be set by register setting under control.

In the RF amplifier 6 of this embodiment, variable gain amplifiers 63 and 54 for removing the influence of stray light, which will be described later, are provided on the output sides of the operational amplifiers 61 and 52, respectively. There is.

By the way, the constant Kt of each of the TE system and TC system
The optimum values of e and Ktc are the optical pickup 5 and the RF amplifier 6.
It is necessary to adjust and set the constants Kte and Ktc for each optical disk device due to variations in each amplifier in FIG.

Therefore, in the present embodiment, for example, as a part of the manufacturing process of the optical disk device, a process of making adjustments to acquire optimum values of the constants Kte and Ktc (acquisition process).
The adjustment results (constants Kte, Ktc
(Optimal value of) is stored in the storage area of the memory 17 or the like for each optical disk device (storing step), thereby completing the manufacture of the optical disk device. As a result, the adjustment result (optimum values of constants Kte and Ktc) stored in the memory 17 by using the system controller 16 which is in charge of the overall control when the optical disk device is started up as the setting means is set in the RF variable gain amplifier 49 of the LSI configuration. , 50 registers, it is possible to perform the arithmetic processing in accordance with the arithmetic expressions (10) and (11) in actual use.

The adjustment processing for obtaining the optimum values of these constants Kte and Ktc will be described here. In FIG. 5, TEOFS and TCO for the variable gain amplifiers 53 and 54
FS is for setting the offset amount of the track error signal TE and the track cross signal TC, and the gains TEGAIN and TCGAIN are set in the variable gain amplifiers 53 and 54, respectively. Since the track cross signal TC is the sum signal as described above, it is very sensitive to the offset. In particular, in the case of a configuration using a hologram laser like the semiconductor laser unit 21 in the present embodiment, due to the configuration of the optical system, reflection from the optical disc 1 is inevitably reflected on each of the light receiving areas A to F of the light receiving element 33. Not only light, but also leaked light due to diffused reflection and diffraction inside the optical system enters to some extent. This is called “stray light”. Generally, if the stray light has the same area, it is considered that the stray light enters into any light receiving area to the same extent, and therefore the track error signal T
A difference signal such as E or the focus error signal FE cancels out the influence thereof, so that it does not pose a problem. On the other hand, since a sum signal such as the track cross signal TC has a very large effect, generally, the optimum value of the constant K for the track cross signal TC system is also set for the track error signal TE system. . Of course, the offset amount TEOF
By adjusting the settings of S and TCOFS at the time of mounting the optical disc 1 in the optical disc device, it is possible to make both the amplitude of the track error signal TE and the offset amount into appropriate states, If there is a deviation, problems such as a decrease in amplitude and an increase in offset are likely to occur when the objective lens 25 is shifted.

Therefore, in the present embodiment, in obtaining the optimum Kte value, the objective lens 25 is moved by a certain amount in the radial direction by the tracking actuator while the focus servo is applied to the optical disc 1, for example, 250.
The optimum value of Kte is acquired under bad conditions with a shift of about μm.

As for the Kte value, as described above, an optimum value may be obtained in advance by adjustment as part of the manufacturing process of the optical disk device and stored in the memory 17 or the like, but the adjustment time is extremely long. Because it takes only a short time, K
An optimum value for the tc value is previously obtained by adjustment as part of the manufacturing process of the optical disk device and is stored in the memory 17 or the like. However, for the Kte value, it may be performed during the mounting process of the optical disk 1. .

FIG. 6 is a flow chart showing an example of control processing as Kte adjusting means executed by the system controller 16. First, the optimum value (adjustment value) of Ktc that is acquired in advance in the manufacturing process and stored in the memory 17 as a storage unit is acquired (step S1), and this value Ktc is set as the initial value of Kte (S2). Originally, the values of Kte and Ktc are only slightly different, so Ktc is the initial value of Kte.
By using the value of, the optimum value of Kte can be obtained in a short time. Subsequently, while the optical disc 1 is rotated by the spindle motor 2, the focus actuator is operated to apply the focus servo (S3), and the amplitude of the track error signal TE is adjusted to a predetermined value (S4), and the objective lens 25 Is located on the center of the track. After that, the tracking actuator is driven to move the objective lens 25 in the radial direction by a predetermined amount, here, 2
It is shifted by 50 μm (S5). This step S5
Is executed as a function of the shift control means. Under such a lens-shifted bad condition, the value of the constant Kte is adjusted so that the offset amount of the track error signal TE becomes the minimum (= 0) (S6) to obtain the optimum Kte value. The process of step S6 is executed as a function of the Kte value update adjusting means. The obtained optimum value of Kte is Te
A register is set as the gain value of the variable gain amplifier 49 (S7), and the subsequent mounting process is executed (S8).
The process of step S7 is executed as a function of the setting means.

On the other hand, in order to obtain the optimum K value for the track cross signal TC, that is, the Ktc value, it is first necessary to measure the influence amount of stray light. FIG. 7 is a flowchart showing an example of control processing executed by the system controller 16 as Kte adjusting means and Ktc adjusting means.

First, the optical disc 1 is rotated by the spindle motor 2 (S11), and the semiconductor laser (LD) 32 is rotated.
Is turned on (S12), the relationship between the constant K value and the offset amount TCOFS (the amount of influence of the stray light component) is acquired in the presence of stray light with the focus servo turned off (S13). The relationship between the constant K value and the offset amount TCOFS is, for example,
As shown in FIG. 8, the slope of the characteristic curve shown in the figure represents the influence of stray light. In the illustrated example, the relationship between the constant K value and the offset amount TCOFS is y = 0.25x +
The case is set to 50.33. The process of step S13 is executed as a function of the influence amount acquisition means. In addition,
In order to obtain this relationship, it may be performed with the optical disc 1 not loaded (no disc). The acquired relationship is stored in the memory 17 or the like.

Thereafter, this time, with the focus servo applied by the focus actuator (S14), the value of the constant Ktc is adjusted and set so that the offset amount of the track cross signal TC becomes the minimum (= 0) (S15). . Then, the offset amount TCOFS for this Ktc is set from the relationship shown in FIG. 9 described above (S16), and the offset amount of the track cross signal TC is measured again. If the track cross signal TC has an offset amount (S1
7 N) and Ktc are adjusted and set again (S15). Such processing is repeated until the offset amount of the track cross signal TC is exhausted (Y in S17), and the optimum value of Ktc is acquired (S18). The processing of these steps S14 to S18 is executed as a function of the Ktc value update adjusting means. The acquired optimum value of Ktc is registered in the register as the gain value of the TC gain variable amplifier 50 (S19). Step S
The processing of 19 is executed as a function of the setting means. Also,
The processing of these steps S11 to S19 is executed as a function of the Ktc adjusting means.

Subsequent processing as Kte adjusting means for Kte is executed in the same manner as in the case shown in FIG.

The processing shown in steps S11 to S19 may be performed each time the optical disk device is activated and the optical disk 1 is mounted. However, in reality, the adjustment time and the optical disk-free state are set. Therefore, in order to completely eliminate the influence of stray light, it can be said that it is preferable to perform it at the final stage as part of the manufacturing process of the optical disk device.

A second embodiment of the present invention will be described with reference to FIGS. 9 and 1.
A description will be given based on 0. The same parts as those shown in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.
This embodiment shows an application example in the case where Kte and Ktc cannot be individually set as the constant K in the arithmetic expression due to the system configuration.

In this case, basically, it can be said that the value of the constant K should be set on the basis of the track cross signal TC which is easily affected by the offset as described above. That is,
K = Ktc. However, in general terms, CD-
Many reproduction-only stamp discs, such as ROMs, have poor mechanical characteristics, and the signal amplitude of the track error signal TE may be smaller than that of a recordable disc such as a CD-R. . Even if the signal amplitude and offset of the track error signal TE can be canceled by increasing the signal gain by setting TEGAIN and TEOFS and performing offset adjustment, that is at the lens center position, and the objective lens 25 When the shift is performed, the track error signal does not intersect the reference level Vref (see FIG. 10) and is interrupted, which may hinder the seek operation. Further, since the track cross signal TC is a track crossing signal, its signal amplitude differs between a portion with data and a portion without data. In particular, in the case of seeking a portion where a recorded portion and an unrecorded portion are mixed, such as the PCA area, there is an amplitude variation, so a more correct K value is required.

In consideration of such a point, in the present embodiment, the system controller 16 is made to execute the control shown in the flowchart of FIG. The value Ktc that minimizes the optical offset amount of the track cross signal TC is assumed to be acquired and stored in advance in the manufacturing process.

First, the value of the constant Ktc, which is acquired in advance, is set as the value of the constant K. That is, K = Ktc (S
21). The process of step S21 is executed as a function of the adjustment value initial setting means.

Next, the loaded optical disc 1 is rotated by the spindle motor 2 and the focus actuator is driven to turn on the focus servo (S22). In this state, the track error signal TE
Is measured (S33), and if this signal amplitude is larger than the predetermined level TEth (N in S34), it is determined that the optical disc 1 is a recordable optical disc, and the mount process is executed with K = Ktc (S41). . That is, K = Ktc is used for a recordable disc.

On the other hand, if the signal amplitude of the track error signal TE is equal to or lower than the predetermined level TEth (Y in S34), tracking control is performed to turn on the track (S35) to determine whether ATIP can be detected on the track. Judge (S
36). If ATIP can be detected (Y in S36), it is determined that the optical disc 1 is a recordable optical disc, and the mount process is executed with K = Ktc (S41). If ATIP cannot be detected (N in S36), it is determined that the read-only ROM disk is used, and the tracking actuator shifts the objective lens 25 by a fixed amount, here +250 μm (S37), and the offset of the track error signal TE. The optimum Kte value is obtained by adjusting the value of the constant Kte so that the amount becomes the minimum (= 0) (S38). The optimum value of the obtained Kte is set as the K value, that is, K = Kte is set (S39), and it is removed from the track again (S4).
0) and subsequent mount processing is executed (S41). The processing of steps S34 to S36 is executed as a function of the disk type determination means, and the processing of steps S37 to S39 is executed as a function of the adjustment value change setting means.

After obtaining the optimum value of Kte by the processing of step S38, as shown in FIG. 11, the average value of the initial Ktc and this Kte is calculated (S42), and this average value is set to K.
May be set as the value of (S43).

[0102]

According to the invention described in claim 1, the constant K value is originally set by switching the gain of the amplifier for arithmetically generating the track error signal TE and the track cross signal TC. Regarding the constant K value, the constant Kte for the track error signal TE and the track cross signal T
Since the constant Ktc for C can be individually set by the setting means, when it is difficult to suppress the crosstalk between the main beam and the sub-beams, a track error signal by a differential push-pull signal by three beams is generated. To provide an optical disk device capable of appropriately dealing with the constant K even if the value of the constant K required for calculation with the track cross signal is different, by individually setting each, and thus realizing stable tracking servo and seek characteristics. You can

According to the invention described in claim 2, in realizing the invention described in claim 1, it is necessary to make adjustments for each optical disk device due to variations in the optical pickup and the operational amplifier. By obtaining Kte and Ktc in advance in the manufacturing stage and storing them in a usable state at the time of startup, it is possible to promptly mount the optical disc without burdening the firmware.

According to the invention described in claim 3, the constant Ktc, which requires a relatively long time for adjustment in realizing the invention described in claim 1, is obtained in advance in the manufacturing stage and stored in a state that can be used at startup. By doing so, when the optical disk device is activated to mount the optical disk, only the constant Kte, which requires a relatively short time, needs to be adjusted by the Kte adjusting means, and the manufacturing tact and the mount processing time are reduced. In consideration of this, it is possible to provide an optical disk device that can realize stable tracking servo and seek characteristics.

According to the invention of claim 4, in the optical disk device of claim 3, the Kt at the time of disk mounting is set.
The optimum value of the constant Kte can be quickly obtained by using the value of the constant Ktc stored in advance as the initial value of e.

According to the fifth aspect of the invention, in the optical disc device according to the first aspect, at the manufacturing stage of the optical disc device, it is not necessary to individually obtain the optimum values of the constants Kte and Ktc. The invention according to claim 1 can be realized while reducing the adjustment tact in the manufacturing process.

According to the invention of claim 6, in the optical disk device of claim 5, since the track cross signal TC which is the sum signal is easily affected by stray light, the optimum constant Ktc for the track cross signal TC is set. In order to obtain the influence, the influence of stray light is obtained by the influence amount acquisition means, and the track adjustment signal T is obtained by the update adjustment means in consideration of the influence amount.
Since the optimum constant Ktc for C is obtained, the optimum track cross signal TC can be obtained, and stable seek characteristics can be realized.

According to the invention described in claim 7, in the optical disk device according to claim 5, since the track cross signal TC which is the sum signal is easily influenced by stray light, the optimum constant Ktc for the track cross signal TC is set. In order to obtain the influence, the influence of stray light is obtained by the influence amount acquisition means, and the track adjustment signal T is obtained by the update adjustment means in consideration of the influence amount.
Since the optimum constant Ktc for C is obtained, the optimum track cross signal TC can be obtained, and stable seek characteristics can be realized.

According to the invention of claim 8, claim 3,
In the optical disc device described in 5, 6, or 7, when obtaining the optimum value of the constant Kte for the track error signal TE,
Since the Kte value update adjusting means determines the objective lens under bad conditions in which the objective lens is shifted in the radial direction by a certain amount, the track error signal TE can be stably obtained even when the objective lens is shifted. Therefore, it is possible to provide an optical disk device that can realize stable tracking servo and seek characteristics.

According to the present invention, the track error signal TE is small and the offset of the track error signal TE is small even if Kte and Ktc cannot be individually set as the value of the constant K in the system configuration. In the case of a read-only optical disk such as a CD-ROM that may cause a problem, stable tracking servo and seek characteristics can be obtained by using a value Kte that minimizes the offset amount of the track error signal TE as the K value. realizable. On the other hand, in an optical disc in which the disc is not closed, the component of the track cross signal TC in the unrecorded portion is small, but in that case, by setting K = Ktc as in the initial setting, stable tracking servo and seek characteristics are realized. be able to.

According to the invention of claim 10, it is basically the same as the invention of claim 9, and K = K is used as a constant K.
Although it is basically set to Ktc, the track error signal T
In the case of a read-only optical disc such as a CD-ROM in which E is small and the offset of the track error signal TE may be a problem, stable tracking servo is achieved by using the average value of Kte and Ktc as the K value. Seek characteristics can be realized.

According to the invention of claim 11, claim 9 is provided.
Alternatively, in the optical disc device described in the paragraph 10, when obtaining the optimum value of the constant Kte for the track error signal TE, the Kte value update adjusting means is used under bad conditions in which the objective lens is shifted by a certain amount in the radial direction by the shift control means. Since the tracking error signal TE is obtained in a stable manner even when the objective lens is shifted, it is possible to provide an optical disk device capable of realizing stable tracking servo and seek characteristics.

According to the twelfth aspect of the invention, the optical disk device according to any one of the first to eleventh aspects of the invention is provided with the holographic laser in which crosstalk relating to the track error signal TE and the track cross signal TC is difficult to avoid. The action and effect can be effectively exhibited.

According to the thirteenth aspect of the present invention, the constant K value is originally set by switching the gain of the amplifier for arithmetically generating the track error signal TE and the track cross signal TC. Regarding the value, the constant Kte for the track error signal TE and the track cross signal T
Since the variable gain amplifier for TE and the variable gain amplifier for TC that are individually set as the constant Ktc for C are provided, when it is difficult to suppress the crosstalk between the main beam and the sub beam, the differential push-pull with three beams is performed. Even if the value of the constant K necessary for the calculation of the track error signal and the track cross signal by the signal is different, by mounting the calculation circuit, it is possible to appropriately deal with each individual setting, and thus stable. It is possible to provide an optical disk device that can realize tracking servo and seek characteristics.

According to the fourteenth aspect of the invention, the constant K value is originally set by switching the gain of the amplifier for arithmetically generating the track error signal TE and the track cross signal TC. Regarding the value, the constant Kte for the track error signal TE and the track cross signal T
As the constant Ktc for C, TE = MAINpp-Kte * SUBpp TC = MAINsum-Ktc * SUBsum is configured so that the crosstalk between the main beam and the sub beam is difficult to suppress. Even if the value of the constant K required for the calculation of the track error signal and the track cross signal by the differential push-pull signal by the beam is different, by mounting the calculation circuit, it is possible to appropriately deal with each by individual setting. Therefore, it is possible to provide an optical disk device that can realize stable tracking servo and seek characteristics.

According to the fifteenth aspect of the invention, the constant K value is originally set by switching the gain of the amplifier for arithmetically generating the track error signal TE and the track cross signal TC. The track error signal TE is related to this constant K value in advance in the manufacturing stage of
Since it is possible to individually set the constant Kte for scanning and the constant Ktc for the track cross signal TC, if it is difficult to suppress the crosstalk between the main beam and the sub-beams, the differential push-pull signal by three beams is used. Even if the value of the constant K necessary for the calculation of the track error signal and the track cross signal is different from each other, it is possible to appropriately deal with the individual settings, so that stable tracking servo and seek characteristics can be realized. A method for manufacturing a device can be provided.

According to the invention of claim 16, claim 1
Although it is similar to the invention described in 5, it is necessary to make adjustments for each optical disk device due to variations in optical pickups and operational amplifiers, but individual constants Kte and Ktc can be obtained in advance at the manufacturing stage and used at startup. By storing in the state, the mounting process of the optical disk can be promptly performed without burdening the firmware.

According to the invention of claim 17, claim 1
6 is the same as that of the invention described above, but the constant Ktc, which requires a relatively long time to adjust, is obtained in advance in the manufacturing stage and stored in a usable state at the time of startup, so that the optical disk device is activated and the optical disk When the mounting process is performed, only the adjustment of the constant Kte needs to be performed in a relatively short time, and in consideration of the manufacturing tact and the mounting process time, an optical disk device that can realize stable tracking servo and seek characteristics can be realized. A manufacturing method can be provided.

According to the invention of claim 18, claim 1
In the method for manufacturing an optical disk device described in 5 or 16,
When the optimum value of the constant Kte for the track error signal TE is obtained, it is obtained under the bad condition that the objective lens is shifted by a certain amount in the radial direction. Therefore, even if the objective lens is shifted, the track error signal TE is obtained. Thus, it is possible to provide a method for manufacturing an optical disk device capable of realizing stable tracking servo and stable seek characteristics.

According to the invention of claim 19, claim 1
In the method of manufacturing an optical disk device according to any one of 5 to 18, the track cross signal TC, which is a sum signal, is easily affected by stray light.
Since the influence of stray light is obtained in order to obtain the optimum constant Ktc for C, and the optimum constant Ktc for the track cross signal TC is obtained in consideration of the amount of the influence, the optimum track cross signal TC can be obtained. Stable seek characteristics can be realized.

According to the invention of claim 20, claim 1
In the method of manufacturing an optical disk device according to any one of 5 to 18, the track cross signal TC, which is a sum signal, is easily affected by stray light.
Since the influence of stray light is obtained in order to obtain the optimum constant Ktc for C, and the optimum constant Ktc for the track cross signal TC is obtained in consideration of the amount of the influence, the optimum track cross signal TC can be obtained. Stable seek characteristics can be realized.

[Brief description of drawings]

FIG. 1 shows a CD-R / R as a first embodiment of the present invention.
It is a block diagram which shows the structural example of a W drive apparatus.

FIG. 2 is a configuration diagram of an optical system showing the optical pickup.

FIG. 3 is a schematic cross-sectional view showing a configuration example of the semiconductor laser unit.

FIG. 4 is an explanatory diagram showing a DPP method using three beams.

FIG. 5 is a circuit diagram showing a configuration example of an RF amplifier.

FIG. 6 is a schematic flowchart showing an example of processing control.

FIG. 7 is a schematic flowchart showing another example of processing control.

FIG. 8 is a characteristic diagram showing a relationship between a K value and TCOFS as an influence amount of stray light.

FIG. 9 is a schematic flowchart showing an example of processing control according to a second embodiment of the present invention.

FIG. 10 is an explanatory diagram showing an offset state.

FIG. 11 is a schematic flowchart showing a modification of the processing control example.

[Explanation of symbols]

1 optical disc 5 Optical pickup 6 computing means, computing circuit 17 Storage means 25 Objective lens 32 light sources 34 Hologram element 49 TE Variable Gain Amplifier Variable gain amplifier for 50 TC S1 to S6 Kte adjusting means S5 shift control means S6 Kte value update adjustment means S7 setting means S13 Influence amount acquisition means S14 to S18 Ktc value update adjusting means S11 to S19 Ktc adjusting means S34 to S36 disc type determination means S37 to S39 adjustment value changing means

Claims (20)

[Claims] 1. A main beam and two sub-beams
Optical pickup using a beam differential push-pull method, and a track error signal T based on a differential push-pull signal based on reflected light components from the optical disc of the main beam and the two sub-beams of the three beams.
E and a calculation means for generating a track cross signal TC, wherein the main beam push-pull component is MAINpp, the sum signal component is MAINsum, the two sub-beam push-pull components are SUBpp, and the sum signal component is SUBsum, When a settable constant is set to K, an optical disk device for performing the calculation represented by TE = MAINpp-K * SUBpp TC = MAINsum-K * SUBsum by the calculation means, wherein the constant K used by the calculation means is An optical disk device comprising setting means for individually setting the constant Kte for the track error signal TE and the constant Ktc for the track cross signal TC. 2. A storage unit that stores the values of the optimum constants Kte and Ktc previously obtained by adjusting each optical disc device when the optical disc device is manufactured so as to be usable by the setting unit when the optical disc device is started. The optical disk device according to claim 1, further comprising: 3. A storage unit that stores the value of the optimum constant Ktc previously obtained by adjusting each optical disc device when the optical disc device is manufactured so as to be usable by the setting unit when the optical disc device is activated. 2. The optical disk device according to claim 1, further comprising Kte adjusting means for performing an adjustment each time the optical disk device is activated and mounting the optical disk to obtain an optimum constant Kte value and provide it to the setting means. 4. The Kte adjusting means stores the constant Ktc stored in the storing means as an initial value of the constant Kte.
The optical disk device according to claim 3, wherein 5. The optimum constant K is adjusted every time the optical disk device is started and the optical disk is mounted.
2. The optical disk device according to claim 1, further comprising a Kte adjusting means and a Ktc adjusting means for obtaining the values of te and Ktc and supplying them to the setting means. 6. The Ktc adjusting means obtains an influence amount of a stray light component of the light source in a focus-off state of the optical pickup for adjustment for obtaining an optimum value of a constant Ktc for the track cross signal TC. A value of a constant Ktc so as to minimize the offset amount of the track cross signal TC after removing the influence of the stray light component based on the influence amount of the stray light component in the acquisition unit and the focus servo of the optical pickup. 6. The optical disk device according to claim 5, further comprising update adjusting means for adjusting. 7. The Ktc adjusting means obtains an influence amount for obtaining an influence amount of a stray light component of a light source of the optical pickup without an optical disc for adjustment for obtaining an optimum value of a constant Ktc for the track cross signal TC. Means for removing the influence of the stray light component on the basis of the influence amount of the stray light component in the state where the focus servo of the optical pickup is applied to the loaded optical disc.
6. The optical disk device according to claim 5, further comprising update adjusting means for adjusting the value of the constant Ktc so that the offset amount of C is minimized. 8. The Kte adjusting unit shifts the objective lens in the optical pickup with respect to the optical disc in a radial direction in order to adjust the optimum value of the constant Kte for the track error signal TE.
6. A Kte value update adjusting means for adjusting the value of the constant Kte so that the offset amount of the track error signal TE when the objective lens is shifted by a certain amount in the radial direction is minimized. 6. The optical disk device according to 6 or 7. 9. A main beam and two sub-beams
Optical pickup using a beam differential push-pull method, and a track error signal T based on a differential push-pull signal based on reflected light components from the optical disc of the main beam and the two sub-beams of the three beams.
E and a calculation means for generating a track cross signal TC, wherein the main beam push-pull component is MAINpp, the sum signal component is MAINsum, the two sub-beam push-pull components are SUBpp, and the sum signal component is SUBsum, An optical disk device for performing a calculation represented by TE = MAINpp-K * SUBpp TC = MAINsum-K * SUBsum, where K is a settable constant, and which is an optical disc of the track cross signal TC. Adjustment value initial setting means for setting the value Kte that minimizes the offset amount as the value of the constant K, and the amplitude of the track error signal TE at the time of mounting the disk, and the type of the optical disk is determined according to the magnitude of the amplitude. Disc type determining means for determining, and the type of the optical disc is determined to be a read-only disc when the amplitude of the track error signal is below a predetermined level. Optical disc apparatus having an adjustment value changing setting means for setting a value Kte the offset amount of the track error signal TE is the minimum as the value of the constant K in the case were. 10. An optical pickup using a differential push-pull method using three beams of a main beam and two sub beams, and the main beam in the three beams.
Arithmetic means for generating a track error signal TE and a track cross signal TC by a differential push-pull signal based on a reflected light component from the optical disc with the one sub-beam, and a push-pull component of the main beam is summed with MAINpp, When the signal component is MAINsum, the push-pull component of the two sub-beams is SUBpp, the sum signal component is SUBsum, and the settable constant is K, TE = MAINpp-K * SUBpp TC = MAINsum-K * SUBsum by the calculating means. And an adjustment value initial setting means for setting the value Kte that minimizes the optical offset amount of the track cross signal TC as the value of the constant K. Disc type determination that measures the amplitude of the track error signal TE and determines the type of optical disc based on the magnitude of the amplitude And a value Kte that minimizes the offset amount of the track error signal TE when the type of the optical disk is judged to be a read-only disk when the amplitude of the track error signal is below a predetermined level. Adjustment value change setting means for setting an average value with Ktc as the value of the constant K,
Optical disk device having the. 11. The adjustment value change setting means includes shift control means for shifting an objective lens in the optical pickup for an optical disc in a radial direction, and the track error when the objective lens is shifted by a certain amount in the radial direction. 11. The optical disk device according to claim 9, further comprising a Kte value update adjusting unit that adjusts the value of Kte so that the offset amount of the signal TE is minimized. 12. The optical disk device according to claim 1, wherein the optical pickup uses a hologram laser as a light source. 13. An optical disc connected to the output side of an optical pickup using a differential push-pull method using three beams of a main beam and two sub beams, and an optical disc of the main beam and the two sub beams of the three beams. The differential push-pull signal based on the reflected light component is the track error signal TE, the cross-track signal is the track cross signal TC, and the push-pull component of the main beam is MAIN.
pp, sum signal component is MAINsum, push-pull component of the two sub-beams is SUBpp, sum signal component is SUBsum, and a settable constant is K. TE = MAINpp-K * SUBpp TC = MAINsum-K * SUBsum An arithmetic circuit for performing the operation represented, wherein the constant K is individually set as a constant Kte for the track error signal TE and a constant Ktc for the track cross signal TC, and a variable gain amplifier for TE and a gain for TC An arithmetic circuit each having a variable amplifier. 14. A main beam and two sub-beams are connected to the output side of an optical pickup using a differential push-pull method using three beams, and the main beam and the two sub-beams of the three beams from an optical disk are connected. The differential push-pull signal based on the reflected light component is the track error signal TE, the cross-track signal is the track cross signal TC, and the push-pull component of the main beam is MAIN.
pp, sum signal component is MAINsum, push-pull component of the two sub-beams is SUBpp, sum signal component is SUBsum, and a settable constant is K. TE = MAINpp-K * SUBpp TC = MAINsum-K * SUBsum An arithmetic circuit for performing the operation represented, wherein the constant K is individually set as a constant Kte for the track error signal TE and a constant Ktc for the track cross signal TC, TE = MAINpp-Kte * SUBpp TC = MAINsum -A calculation circuit that performs the calculation represented by Ktc * SUBsum. 15. An optical pickup using a differential push-pull method using three beams of a main beam and two sub beams, and the main beam in the three beams.
Arithmetic means for generating a track error signal TE and a track cross signal TC by a differential push-pull signal on the basis of reflected light components from the optical disc of the two sub-beams, the push-pull component of the main beam being MAINpp, the sum When the signal component is MAINsum, the push-pull component of the two sub-beams is SUBpp, the sum signal component is SUBsum, and the settable constant is K, TE = MAINpp-K * SUBpp TC = MAINsum-K * SUBsum by the calculating means. In the method of manufacturing an optical disk device, the constant K used in the calculating means is adjusted to the constant Kte for the track error signal TE by adjusting each optical disk device when manufacturing the optical disk device. The acquisition step of acquiring the optimum value as the constant Ktc for the track cross signal TC, and the acquired values of the constants Kte and Ktc are described before. Method of manufacturing an optical disk apparatus and a setting step of setting relative calculating means. 16. An optical pickup using a differential push-pull method using three beams of a main beam and two sub beams, and the main beam in the three beams.
Arithmetic means for generating a track error signal TE and a track cross signal TC by a differential push-pull signal on the basis of reflected light components from the optical disc of the two sub-beams, the push-pull component of the main beam being MAINpp, the sum When the signal component is MAINsum, the push-pull component of the two sub-beams is SUBpp, the sum signal component is SUBsum, and the settable constant is K, TE = MAINpp-K * SUBpp TC = MAINsum-K * SUBsum by the calculating means. In the method of manufacturing an optical disk device, the constant K used in the calculating means is adjusted to the constant Kte for the track error signal TE by adjusting each optical disk device when manufacturing the optical disk device. The obtaining step of obtaining the optimum value as the constant Ktc for the track cross signal TC and the obtained values of the constants Kte and Ktc are applied. Method of manufacturing an optical disk apparatus having a storing step to store available at startup of the optical disk apparatus. 17. An optical pickup using a differential push-pull method using three beams of a main beam and two sub-beams, and the main beam in the three beams.
Arithmetic means for generating a track error signal TE and a track cross signal TC by a differential push-pull signal on the basis of reflected light components from the optical disc of the two sub-beams, the push-pull component of the main beam being MAINpp, the sum When the signal component is MAINsum, the push-pull component of the two sub-beams is SUBpp, the sum signal component is SUBsum, and the settable constant is K, TE = MAINpp-K * SUBpp TC = MAINsum-K * SUBsum by the calculating means. In the method of manufacturing an optical disk device, the constant K used in the calculating means is adjusted to the constant Kte for the track error signal TE by adjusting each optical disk device when manufacturing the optical disk device. The acquisition step of acquiring the optimum value of the constant Ktc as the constant Ktc for the track cross signal TC, and the acquired value of the constant Ktc are set to the optical value. Method of manufacturing an optical disk apparatus having a storing step to store available to startup disk apparatus. 18. The adjustment for obtaining the optimum value of the constant Kte for the track error signal TE in the acquisition step is performed by the track error signal when the objective lens in the optical pickup with respect to the optical disc is shifted by a certain amount in the radial direction. The constant K is set so that the TE offset amount is minimized.
16. The method according to claim 15, wherein the value of te is adjusted.
Or the method for manufacturing an optical disk device according to item 16. 19. The adjustment for obtaining the optimum value of the constant Ktc for the track cross signal TC in the obtaining step includes a step of obtaining an influence amount of a stray light component of the light source in a focus-off state of the optical pickup, and the optical pickup. The step of adjusting the value of the constant Ktc so as to minimize the offset amount of the track cross signal after removing the influence of the stray light component on the basis of the influence amount of the stray light component with the focus servo applied. 19. The method for manufacturing an optical disk device according to claim 15, wherein the method is used. 20. The adjustment for obtaining the optimum value of the constant Ktc for the track cross signal TC in the obtaining step includes a step of obtaining an influence amount of a stray light component of a light source of the optical pickup in a state without an optical disc, and a loading of the optical disc. Then, with the focus servo of the optical pickup being applied, the influence of the stray light component is removed based on the influence amount of the stray light component, and then the value of the constant Ktc is adjusted so that the offset amount of the track cross signal is minimized. 19. The method for manufacturing an optical disk device according to claim 15, wherein the method is performed by the following steps.