JPH09305976A - Optical disk recording and reproducing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a precise wobble signal stable by a method wherein a substation circuit which finds the difference between the output of a first nonsplit photodetector delayed by a delay circuit and the output of a second nonsplit photodetector is installed as a wobble signal generation means. SOLUTION: A main beam L1 scans a track on an optical disk, a preceding means L2 scans an area on the outer circumferential side adjacent to the track, and a succeeding beam L3 scans an area on the inner circumferential side in the same manner. Regarding irradiation positions of the respective means, the preceding beam L2 and the succeeding beam L3 are separated by a distance L so as to sandwich the main beam L1. Beams of reflected light of the respective beam L1 to L3 are detected respectively by a photodetector S1 and nonsplit photodetectors S2, S3. The output signal A of the photodetector S2 is input to a subtraction circuit 2 as a signal C via a delay circuit 1. On the other hand, the output of the photodetector S3 is input to the subtraction circuit 2 as it is. The difference signal PP of both inputs is output from the subtraction circuit 2 so as to become a wobble signal W through a BPF 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a read-only optical disc, a rewritable optical disc, and an optical disc recording / reproducing apparatus which records / reproduces information on / from a rewritable optical disc by optical modulation or magnetic field modulation. is there.

[0002]

2. Description of the Related Art As shown in FIG.
In Fig. 1, a track (guide groove) 92 is formed to perform tracking control of the light beam, and the end surface of the track has a sine wave shape (generally called a wobble shape) having a predetermined amplitude and period along the track. Is out). In the optical disc recording / reproducing apparatus, a wobble signal corresponding to this wobble shape is generated, and the wobble signal is used as timing information when recording information on the optical disc, and also servo control of an optical disc rotation driving means such as a spindle motor is performed. It is used for

In a conventional optical disk recording / reproducing apparatus, there is a method called a one-beam method for generating a wobble signal. As shown in FIG. 7, the reflected light of the main beam L1 for scanning a track on the optical disk is made into a cross shape. The four output signals S1′a, S1′b, S1′c, and S1′d are made incident on the four-divided photodetector S1 ′ and processed by two adder circuits 701, 702 and subtractor circuit 703 to obtain Also, the difference signal (S1'a + S1'd)-(S1'b + S1 ') between the two components divided in the direction parallel to the track.
The wobble signal is extracted by the bandpass filter 704 from c).

In addition, there is a so-called two-beam system, and as shown in FIG. 8, two light beams, a leading beam L2 and a trailing beam L3, are separated from each other by a distance L between the leading beam and the trailing beam. In advance, the optical disc is irradiated with the positional relationship shown in the figure, and the respective reflected lights are made incident on the photodetectors S2 'and S3' divided into two in the direction parallel to the track, and the delay circuit 1 makes a predetermined time. T (T = L / V,
V: linear velocity) delayed from the difference signal (S2′a−S2′b) of the two signals output from the photodetector S2 ′ and passing through the subtraction circuit 801, and the bandpass filter 8
04, and the difference signal (S3′a−S) of the two signals output from S3 ′ via the subtraction circuit 802.
The signal extracted from 3′b) by the bandpass filter 805 is combined by the adder circuit 803 to generate a wobble signal.

[0005]

However, the above-mentioned 1
The beam system has a problem that the track servo is disturbed by the influence of the tilt of the optical axis and the offset of the light beam, and as a result, it becomes difficult to generate the wobble signal.

Further, in the above-mentioned two-beam system, since a two-divided photodetector is adopted as two photodetectors for detecting the reflected lights of the two beams, a complicated circuit is required for generating the wobble signal. Will be required.

Therefore, according to the present invention, an accurate wobble signal can be stably generated without being affected by the inclination of the optical axis and the offset of the light beam, and the circuit structure for generating the wobble signal is compact. It is an object of the present invention to provide an optical disc recording / reproducing device having the above structure.

[0008]

In order to achieve the above object, in the invention described in claim 1, a main beam for scanning a track formed on an optical disk and a track which is scanned by the main beam are adjacent to each other. In the optical disc recording / reproducing apparatus, the optical disc is provided with means for irradiating the optical disc with three light beams: a preceding beam for scanning one region and a trailing beam for scanning the other region. First non-split photodetector that detects the reflected light of and outputs an electric signal corresponding to the reflected light amount; and a first non-split photodetector that detects the reflected light of the trailing beam and outputs an electric signal corresponding to the reflected light amount. A wobble signal corresponding to a wobble shape in which an end face of a track formed on an optical disk has a predetermined amplitude and a period along with the track, which has two non-split photodetectors. As wobble signal generating means, a delay circuit for delaying a signal output from the first non-split photodetector for a predetermined time, and an electric signal output from the first non-split photodetector delayed by the delay circuit And a subtraction circuit for taking the difference between the electric signal output from the second non-split photodetector.

With such a structure, the three-beam type optical head prevents the disturbance of the track servo caused by the influence of the tilt of the optical axis and the offset of the light beam, and obtains a stable and accurate wobble signal. In addition, two light beams, a preceding beam and a trailing beam, out of the three light beams are used to generate the wobble signal, and a non-split detector is used as a photodetector for detecting the reflected light. ,
The circuit configuration for generating the wobble signal becomes very compact.

According to a second aspect of the present invention, in the optical disk recording / reproducing apparatus according to the first aspect, the delay circuit has a variable signal delay time, and has means for controlling the delay time. ing.

According to a third aspect of the present invention, in the optical disc recording / reproducing apparatus according to the second aspect, when the rotation drive system of the optical disc is CLV control and it is possible to switch to two or more kinds of linear velocities. The delay time of the signal in the delay circuit is set according to the selected linear velocity.

Further, in the invention described in claim 4, in the optical disk recording / reproducing apparatus according to claim 2, when the rotary drive system of the optical disk is a CAV control and has a system for obtaining address information from a reproduction signal. A means for detecting the position of the track scanned by the main beam in the optical disk radial direction based on the address information, and calculating the linear velocity of the track scanned by the main beam from the position, It is assumed that the delay time of the signal in the circuit is divided by the linear velocity of the track, which is the distance between the preceding beam and the following beam.

According to a fifth aspect of the present invention, in the optical disc recording / reproducing apparatus according to the second aspect, the rotary drive system of the optical disc is a CAV control and a system for obtaining address information from the wobble signal is provided. Has means for detecting the optical disc radial direction position of the track being scanned by the main beam based on the address information, and calculating the linear velocity of the track being scanned by the main beam from the position. It is assumed that the delay time of the signal in the delay circuit is divided by the linear velocity of the track, which is the distance between the preceding beam and the following beam.

According to a sixth aspect of the invention, in the optical disk recording / reproducing apparatus according to the fifth aspect,
The number of tracks crossed by each of the main beam, the preceding beam, and the trailing beam by the seek operation is detected, and the track scanned by the main beam by using the number of tracks and the address information immediately before the seek operation together. It has means for detecting the position of the optical disc in the radial direction.

According to a seventh aspect of the invention, in the optical disk recording / reproducing apparatus according to the sixth aspect, immediately after the seek operation, the main beam, the preceding beam, and the following beam cross each other by the seek operation. The number of tracks is detected, and the number of tracks and the address information immediately before the seek operation are used together to detect the radial position of the track scanned by the main beam in the optical disc radial direction. Based on this, the position of the track scanned by the main beam in the radial direction of the optical disc is detected.

According to the above structure, the delay time of the signal in the delay circuit is dynamically set in accordance with the change of the track linear velocity, so that the optical disc rotation control is switched to two or more types of linear velocity. Even with CLV control, or
Even if the CAV control in which the track linear velocity changes continuously and changes greatly before and after the seek operation, a stable and accurate wobble signal can be obtained.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a main beam L of a wobble signal generation circuit in an optical disk recording / reproducing apparatus of the present invention.
It is the figure shown in relation with the scanning position of three light beams of 1, the preceding beam L2, and the following beam L3. In the figure, the main beam L1 scans a track, the outer beam adjacent to the track is scanned by the preceding beam L2, and the inner beam is similarly scanned by the trailing beam L3.

And regarding the irradiation position of each beam,
The leading beam L2 and the trailing beam L3 are separated from each other by the distance L with the main beam L1 interposed therebetween, and the leading beam L2 leads the trailing beam L3 by the distance L.

A photodetector for detecting the reflected light of each beam from the optical disk and outputting an electric signal corresponding to the amount of light is provided for each beam, and the photodetector S1 for the main beam L1 is provided. However, the non-split photodetector S2 is provided for the preceding beam L2, and the non-split photodetector S3 is provided for the following beam L3.

The signal A output from the non-split photodetector S2 is delayed by a predetermined time T in the delay circuit 1 and input to the subtraction circuit 2 as a signal C. On the other hand, the signal B output from the non-split photodetector S3 is directly input to the subtraction circuit 2 without being delayed. The subtraction circuit 2 takes the difference between the two input signals and outputs it as a signal PP. The signal delay time T in the delay circuit 1 divided by the track linear velocity V by the distance L between the preceding beam L2 and the following beam L3 (T = L /
V), the two signals C and B input by the subtraction circuit 2 are both information from one position on the track, and the signal PP output by the subtraction circuit 2 is a bandpass signal having a wobble frequency component as a center frequency. The wobble signal W is obtained by passing through the filter 3.

The above contents will be described more specifically. FIG.
Represents the positional relationship between each light beam and the track at times T ₀ , T ₁ ,
..., each T ₈ is shown, and Fig. 3 (a) (b) (c)
(D) shows the signals A, B, C, and PP on the time axis, respectively. In FIG. 2, the track is partially wobbled for convenience of explanation. First, regarding the signal A, at time T ₀ , the preceding beam L2 is at the farthest position from the track, and is a position where it is less susceptible to light scattering by the track. That is, the signal A becomes maximum at time T ₀ . After that, as time T ₁ and T ₂ progress, the preceding beam L2 enters the track and is scattered by the track. Therefore, time T ₀
From time T ₁ to time T ₂ , the signal A decreases. After time T _3, the preceding beam L2 rushes into a track that does not have a wobble shape, and the positional relationship between the preceding beam and the track does not change, so the signal A becomes constant.

Next, looking at the signal B, the time T
_{At 0} , the trailing beam L3 is at the farthest position from the track, and is a position where the light is hardly scattered by the track.
That is, the signal B becomes maximum at time T ₀ . After that, as time T ₁ , T ₂ , and T ₃ progress, the preceding beam L2 enters the track and is scattered by the track. Therefore, the signal B decreases from time T ₀ to time T ₁ , T ₂ , T ₃ and reaches a minimum at time T ₄ .
Then, as the time T ₅ and the time T ₆ progress, the trailing beam L3 moves away from the track and becomes less susceptible to light scattering by the track. Therefore, the signal B increases from time T ₄ to time T ₅ , T ₆ . After time T _7, the trailing beam L3 rushes into a track that does not have a wobble shape,
Since the positional relationship between the trailing beam and the track does not change, the signal B becomes constant.

Since the signal C is obtained by delaying the signal A by L / V, it becomes as shown in FIG. 3C, and the signal PP (CB) output from the subtraction circuit 2 is as shown in FIG. It becomes as shown in (3) of 3. Although not shown in FIG. 3, in reality, each signal includes an RF component (high frequency component) associated with the reproduction of the pits formed on the track, and therefore the band pass filter 3 having the wobble frequency component as the center frequency is used. The wobble signal W is obtained by passing through.

The wobble signal W obtained as described above
Is accurate because the 3-beam type optical head prevents the disturbance of the track servo caused by the influence of the inclination of the optical axis and the offset of the light beam. Further, since two light beams of the preceding beam and the trailing beam of the three light beams are used for generating the wobble signal, and a non-divided photodetector is used as a photodetector for detecting the reflected light, The circuit configuration for generating the wobble signal is very compact.

Next, an embodiment will be described in which the wobble signal generating circuit is applied to an optical disk recording / reproducing apparatus in which the rotational drive system of the optical disk is CLV control and which can be switched to two or more kinds of linear velocities. FIG. 4 is a diagram showing a portion of the optical disc recording / reproducing apparatus relating to the present invention.
CLV control is performed as follows based on the wobble signal W obtained in the above-described process flow.

The current linear velocity calculator 41 receives the wobble signal W, detects the current track linear velocity from the frequency, and outputs it as the current track linear velocity signal 4a. The target linear velocity output device 42 is the system controller 4
The target linear velocity input from 7 is output as the target linear velocity signal 4b. The subtraction circuit 43 inputs the target linear velocity signal 4b and the current linear velocity signal 4a, takes the difference (4b-4a), and outputs it as a linear velocity error signal 4c. The spindle motor servo circuit 44 inputs the linear velocity error signal 4c, outputs the servo signal 4d to the spindle motor drive circuit 45 in accordance with the linear velocity error signal 4c, changes the drive current 4e supplied to the spindle motor 46 by the spindle motor drive circuit 45, The rotation speed of the optical disk changes.

By doing so, one negative feedback servo loop is formed via the preceding beam L2 and the following beam L3, and the track linear velocity, which is the control amount of CLV control, becomes the target linear velocity. It is possible to control. The system controller 47 has the right to determine the track linear velocity, sets the target linear velocity to be output to the target linear velocity output device 41, and sets an appropriate delay time in the delay circuit 1 which is one element of the servo loop. You can do it.

Next, an embodiment in which the wobble signal generating circuit is applied to an optical disk recording / reproducing apparatus having a system for adopting CAV control for rotation control of an optical disk and obtaining address information from a reproduction signal will be described. FIG. 5 is a diagram showing a portion of the optical disk recording / reproducing apparatus relating to the present invention, and the wobble signal W is obtained by the above-mentioned flow.

By the way, since the disk rotation control is CAV control, the track linear velocity varies depending on the position of the track in the disk radial direction, and increases toward the outer peripheral side.
Therefore, it is necessary to calculate the linear velocity of the track scanned by the main beam L1 and change the signal delay time in the delay circuit 1 accordingly. The flow of the processing will be described below.

Since the main beam L1 is located on the track, the output signal 5a of the photodetector S1 is a reproduction signal of the information recorded on the track, and the address information is output from the output signal I using the address demodulator 51. Can be obtained. The address information is input to the current position detector 52 in the system controller 55 as digital data 5b.

The current position detector 52 uses the digital data 5b.
From this, the position of the track currently scanned by the main beam in the radial direction of the optical disc is detected, and this is output to the present linear velocity calculator 53 as digital data 5c. The current linear velocity calculator 53 calculates the current track linear velocity from the digital data 5c and outputs it to the delay time calculator 54 as digital data 5d. The delay time calculator 54 uses the delay circuit 1
The delay time of the signal at the leading beam L2 and the trailing beam L2
The distance L from 3 is divided by the input digital data 5d (current track linear velocity), and the result is output to the delay circuit 1 as digital data 5e. As a result, the delay time of the signal in the delay circuit 1 becomes the digital data 5e (L / current track linear velocity).

In this way, even in the CAV control in which the track linear velocity varies depending on the position in the radial direction of the disk, the delay time of the signal in the delay circuit 1 is dynamically controlled according to the track linear velocity, so that it is stable. An accurate wobble signal can be obtained.

Next, a description will be given of an embodiment in which the wobble signal generation circuit is applied to an optical disk recording / reproducing apparatus which employs CAV control for rotation control of an optical disk and has a system for obtaining address information from a wobble signal. FIG. 6 is a diagram showing a portion of the optical disk recording / reproducing apparatus relating to the present invention, and the wobble signal W is obtained by the above-described processing flow.

By the way, since the disk rotation control is CAV control, the track linear velocity differs depending on the position of the track in the disk radial direction, and becomes larger toward the outer peripheral side.
Therefore, it is necessary to calculate the linear velocity of the track scanned by the main beam L1 and change the signal delay time in the delay circuit 1 accordingly. In addition, it is necessary to consider so that the wobble signal W can be stably obtained immediately after the seek operation in which the position of the track scanned by the main beam L1 in the radial direction of the optical disk transits. The flow of processing performed based on these contents will be described below.

First, except after the seek operation, the position of the track scanned by the main beam L1 in the radial direction of the optical disk continuously changes, that is, the track linear velocity continuously changes. At this time, the delay time in the delay circuit 1 is set using the wobble signal W as follows.

The address demodulator 61 demodulates address information from the wobble signal W and outputs it to the current position detector 62 as digital data 6a. Current position detector 62
Detects the position of the track currently scanned by the main beam L1 in the optical disc radial direction from the digital data 6a and outputs it as the digital data 6b. The current linear velocity calculator 63 calculates the linear velocity of the track currently scanned by the main beam L1 from the digital data 6b and outputs it to the delay time calculator 64 as digital data 6c. The delay time calculator 64 divides the interval L between the preceding beam L2 and the following beam L3 by the input digital data 6c (current track linear velocity) and outputs it to the delay circuit 1 as digital data 6d. As a result, the delay time of the signal in the delay circuit 1 is the interval L between the preceding beam L2 and the following beam L3.
Is divided by the current track linear velocity calculated by the current linear velocity calculator 63.

By repeating the above-mentioned processing except immediately after the seek operation, the delay time of the signal in the delay circuit 1 can be made appropriate according to the track linear velocity, so that it is stable and accurate. A wobble signal can be obtained.

Next, the setting of the signal delay time in the delay circuit 1 immediately after the seek operation will be described, but before that, the optical disk radial direction positioning servo of the optical head, a so-called seek servo system will be touched upon. The seek servo system in this embodiment is a seek speed control that employs a track count method for detecting the position of the light beam in the radial direction of the optical disc. Therefore, the direct control amount is the feed speed of the optical head.

When the optical head is moved in the radial direction of the optical disk by the seek operation, the preceding beam L2 and the following beam L3 cross the track, so that the output signal PP of the subtraction circuit 2 becomes a sinusoidal signal. This is a binarization circuit 6
In step 5, the binarized pulse signal 6e for each upper and lower half wave is output to the interval counter 66 and the track counter 67.

The interval counter 66 detects a pulse generation interval time of the pulse signal 6e, that is, a time from when the light beam crosses one track to when it crosses the next track, and it is currently searched as digital data 6f. Output to the speed calculator 68. The current seek speed calculator 68 calculates the current seek speed by dividing the track interval previously stored as data by the digital data 6f which is time information, and calculates the current seek speed.
It is output to the digital subtraction circuit 72 as g.

In the track counter 67, the pulse signal 6e
Of the number of pulses, that is, the number of tracks traversed by the light beam after starting the seek operation, and outputs it as digital data 6h to the digital subtraction circuit 70 and the current position detector 62. The track counter 67 resets the number of tracks detected by the reset signal 6p sent from the system controller 77 after the seek operation is completed.

In addition to the digital data 6h, the number of tracks up to the target track set by the target track setting circuit 69 at the start of the seek operation is input to the digital subtraction circuit 70 as digital data 6i. In the digital subtraction circuit 70, the number of remaining tracks up to the target track is calculated by taking the difference between the digital data 6i and 6h, and this is output to the target seek speed calculation circuit 71 as digital data 6j. The target seek speed calculation circuit 71 calculates a seek speed (target seek speed) that should be present from the digital data 6j, and calculates the calculated seek speed.
It is output to the digital subtraction circuit 72 as k.

The digital subtraction circuit 72 uses the digital data 6
By calculating the difference between k and 6g, the error between the target seek speed and the current seek speed is calculated and output as digital data 6l. The digital data 6l is converted into an analog signal 6m by the D / A conversion circuit 73 and output to the optical head feed motor servo circuit 74. The optical head feed motor servo circuit 74 outputs a servo signal 6n to the optical head feed motor drive circuit 75 according to the analog signal 6m. The optical head feed drive circuit 75 supplies a drive current 6o according to the servo signal 6n to the optical head feed motor 76.

As a result, the target track is reached while repeating acceleration / deceleration so as to reach the target seek speed, and the seek operation is completed.

The delay time of the signal in the delay circuit 1 immediately after the seek operation is set by utilizing a part of the seek servo system signal. First, the digital data 6a of the address information demodulated by the address demodulator 61 from the wobble W
Is stored in the address storage register 78 immediately before the seek operation.

The current position detector 62 inputs the digital data 6a (address information immediately before the seek operation) stored in the address storage register 78 and the digital data 6h (the number of tracks traversed by the light beam by the seek operation) from the track counter 67. Then, the optical disc radial direction position of the track which the main beam is currently scanning is detected from these two data, and it is output to the current linear velocity calculator 3 as digital data 6b. Hereinafter, the flow until the delay time of the signal in the delay circuit 1 is set is the same as that other than immediately after the seek operation, and thus the description thereof will be omitted.

Immediately after the seek operation, by performing the above processing, the delay time of the signal in the delay circuit 1 can be made appropriate according to the track linear velocity, so that a stable and accurate wobble signal can be obtained. Can be obtained.

[0048]

As described above, according to the present invention,
The 3-beam type optical head prevents the track servo from being disturbed due to the influence of the tilt of the optical axis and the offset of the light beam, and a stable and accurate wobble signal can be obtained. Since the two light beams of the preceding beam and the following beam of the beams are used, and the non-split detector is adopted as the photodetector for detecting their reflected light, the circuit configuration for generating the wobble signal is very large. It will be compact.

Further, since the delay time of the signal in the delay circuit is dynamically set according to the change of the track linear velocity, even if the optical disc rotation control is CLV control for switching to two or more types of linear velocity, Alternatively, CA in which the track linear velocity changes continuously and changes greatly before and after the seek operation
Even with V control, a stable wobble signal can be obtained.

[Brief description of drawings]

FIG. 1 shows a wobble signal generation circuit in an optical disc recording / reproducing apparatus of the present invention, which uses a main beam L1, a preceding beam L2,
The figure shown in relation with the scanning position of three light beams of trailing beam L3.

FIG. 2 is a diagram showing a positional relationship between a main beam L1, a preceding beam L2, a following beam L3, and a track for each time.

FIG. 3 is a diagram showing signals A, B, C, and PP when the positional relationship between the main beam L1, the preceding beam L2, the following beam L3, and the track is as shown in FIG.

FIG. 4 is a diagram showing a portion related to a wobble signal in the optical disc device according to the present invention.

FIG. 5 is a diagram showing a portion related to a wobble signal in the optical disc device according to the present invention.

FIG. 6 is a diagram showing a portion related to a wobble signal in the optical disc device according to the present invention.

FIG. 7 is a diagram illustrating a wobble signal generation method in a conventional optical disc recording / reproducing apparatus.

FIG. 8 is a diagram illustrating a wobble signal generation method in a conventional optical disc recording / reproducing apparatus.

FIG. 9 is a diagram showing a wobble shape formed by tracks formed on an optical disc.

[Explanation of symbols]

 1 Delay circuit 2 Subtraction circuit 3 Bandpass filter 41 Current linear velocity calculator 42 Target linear velocity output device 43 Subtraction circuit 44 Spindle motor servo circuit 45 Spindle motor drive circuit 46 Spindle motor 47 System controller 51 Address demodulator 52 Current position detector 53 Current Linear Velocity Calculator 54 Delay Time Calculator 55 System Controller 61 Address Demodulator 62 Current Position Detector 63 Current Linear Velocity Calculator 64 Delay Time Calculator 65 Binarization Circuit 66 Interval Counter 67 Track Counter 68 Current Seek Velocity Calculation Device 69 Target track setting circuit 70 Digital subtractor 71 Target seek speed calculator 72 Digital subtractor 73 D / A conversion circuit 74 Optical head feed motor servo circuit 75 Optical head feed motor drive circuit 76 Optical head feed Motor 77 system controller 78 address storage register L1 main beam L2 leading beam L3 trailing beam S1 photodetector S2 non-split photodetector S3 non-split photodetector S1 'four-split photodetector S2' two-split photodetector S3 '2 split photo detector

Claims (7)

[Claims] 1. A main beam for scanning a track formed on an optical disk, a preceding beam for scanning one region of two regions adjacent to a track scanned by the main beam, and another region. 3 with trailing beam scanning
In an optical disk recording / reproducing apparatus having means for irradiating an optical disk with one light beam, a first non-split photodetector for detecting reflected light of the preceding beam and outputting an electric signal according to the reflected light amount; A second non-split photodetector that detects the reflected light of the beam and outputs an electric signal according to the amount of the reflected light, and the end surface of the track formed on the optical disc has a predetermined amplitude and cycle along the track. As a wobble signal generating means for generating a wobble signal corresponding to the wobble shape, the delay circuit delays the signal output from the first non-split photodetector by a predetermined time, and the delay circuit delays the signal. An optical disc comprising: a subtraction circuit for calculating a difference between an electric signal output by the first non-split photodetector and an electric signal output by the second non-split photodetector. Recording and reproducing apparatus. 2. The optical disc recording / reproducing apparatus according to claim 1, wherein the delay circuit has a variable signal delay time, and has means for controlling the delay time. 3. In an optical disk recording / reproducing apparatus capable of switching to two or more kinds of linear velocities in which a rotation drive system of the optical disc is CLV control, a delay time of a signal in the delay circuit is changed according to a selected linear velocity. The optical disc recording / reproducing apparatus according to claim 2, wherein 4. An optical disk recording / reproducing apparatus having a system for obtaining address information from a reproduction signal, wherein a rotary drive system of the optical disk is CAV control, and an optical disk of a track scanned by the main beam based on the address information. It has means for detecting the radial position and calculating the linear velocity of the track being scanned by the main beam from the position, and the delay time of the signal in the delay circuit is set to the interval between the preceding beam and the following beam. The optical disk recording / reproducing apparatus according to claim 2, wherein the linear velocity of the track is divided. 5. An optical disk recording / reproducing apparatus having a system for obtaining address information from the wobble signal, wherein a rotary drive system of the optical disk is CAV control, and a track scanned by the main beam based on the address information is recorded. It has means for detecting the position in the radial direction of the optical disk and calculating the linear velocity of the track scanned by the main beam from the position, and the delay time of the signal in the delay circuit is set to the interval between the preceding beam and the following beam. 3. The optical disk recording / reproducing apparatus according to claim 2, wherein is divided by the calculated linear velocity of the track. 6. The main beam, the preceding beam, and the trailing beam detect the number of tracks crossed by the seek operation, and use the track number and the address information immediately before the seek operation together to detect the main beam. The optical disk recording / reproducing apparatus according to claim 5, further comprising means for detecting a position of the track scanned by the beam in a radial direction of the optical disk. 7. Immediately after the seek operation, the number of tracks crossed by each of the main beam, the preceding beam, and the following beam is detected by the seek operation, and the track number and the address information immediately before the seek operation are used together. The optical disc radial direction position of the track being scanned by the main beam is detected, and the optical disc radial direction position of the track being scanned by the main beam is detected based on the address information except immediately after the seek operation. The optical disk recording / reproducing apparatus according to claim 6, which is characterized in that: