JP2001118268A - Optical information recording/reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such problems that an objective lens can not smoothly follow up the skew of an optical card so that the objective lens keeps the central position, and an optical information recording/reproducing device can not precisely record/reproduce information. SOLUTION: This device is provided with a means detecting the direction of the skew of an optical card 107 from the drive signal of an objective lens 106 and a means applying an offset equivalent to a prescribed current value smaller than a start current value to a drive current of a DC motor 209 in the same direction as the direction of the detected skew and in the direction than an optical head 204 and the optical card 107 are relatively moved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording / reproducing apparatus for recording information on an optical information recording medium or reproducing the recorded information.

[0002]

2. Description of the Related Art Various types of recording media, such as a disk, a card, and a tape, for recording information using light or reading recorded information have been known. These optical information recording media include those that can be optionally recorded and reproduced, those that can be additionally recorded and reproduced,
Some can only be reproduced. In particular, it is considered that the use of an optical card as a recording medium will be expanded due to features such as ease of manufacturing, portability, and accessibility. Various types of optical information recording / reproducing devices for this optical card are provided.

In such an optical information recording / reproducing apparatus,
Recording and playback of information are performed while always performing auto tracking and auto focus control. The recording of information on the recording medium is modulated according to the recording information, and a series of information is recorded as an optically detectable information pit array by scanning the information track with a light beam focused in a minute spot shape. . In addition, reproduction of information from a recording medium
By scanning a light spot of low power that is not recorded on the medium to the information pit row of the information track, detecting reflected light or transmitted light from the medium, and performing predetermined signal processing using the detection signal The recorded information is reproduced.

FIG. 3 is a configuration diagram showing a typical example of an optical head used in such an optical recording / reproducing apparatus. In FIG. 3, a light beam emitted from a semiconductor laser 101 is collimated by a collimator lens 102 and is divided into a plurality of light beams by a diffraction grating 103. The split light beam is divided into a polarizing beam splitter 104, a quarter-wave plate 105, and an objective lens 106.
Is focused on the optical card 107 via the Optical card 10
7 is reflected by the objective lens 106, the 波長 wavelength plate 1
05, detected by the photodetector 109 via the polarizing beam splitter 104 and the toric lens 108. Reproduction and auto-focusing control (hereinafter, referred to as AF) are performed using the 0th-order diffracted light divided by the diffraction grating 103 among the detection signals of the photodetector 109, and autotracking control (hereinafter, referred to as AF) is performed using ± 1st-order diffracted light. AT). A
F is an astigmatism method, and AT is a three-beam method.

FIG. 4A is a schematic plan view of an optical card. A large number of information tracks are arranged in parallel on the optical card 107, and some of them are shown as T1, T2, T3,. These information tracks are tracking tracks tt1 to tt1.
Each is divided by tt4. The tracking tracks tt1 to tt4 are formed of a material having a different light reflectivity from the groove or the information track, and are used as a guide for obtaining a tracking control signal. FIG. 4A shows an example in which information is recorded or reproduced on the track T3. In this example, the 0th-order diffracted light 11 for recording, reproduction, and AF is used.
0 denotes ± 1st order diffracted light 111,1 for AT on track T3.
Reference numeral 12 is applied to tracking tt3 and tt4, respectively. Then, a tracking control signal to be described later is obtained from the reflected lights from the diffracted lights 111 and 112, and control is performed so that the zero-order diffracted light 110 scans the track T3 correctly. Each of the diffracted lights 110, 111, 112 is AF and A
Under the T control, the optical card 107 is scanned left and right in the drawing by a mechanism (not shown) while maintaining the same positional relationship.

The scanning method includes a method of moving an optical system and a method of moving an optical card. In either method, the optical system and the optical card reciprocate relative to each other.
Non-constant speed parts occur at both ends of the optical card. FIG. 4B shows this state. The horizontal axis of FIG. 4B represents the horizontal direction of the optical card, and the vertical axis represents the relative scanning speed between the optical system and the optical card. Usually, the optical card 107
Is used as a recording area.

The home position HP shown in FIG.
Is provided in an area without a track at the scanning end in the track direction, performs focus pull-in with the light beam positioned at the home position HP, and then drives the carriage on which the optical head or the optical card is mounted to drive the optical head. A seek operation for moving a beam and an optical card in a direction perpendicular to the track and accessing a target track is performed.

FIG. 5 shows each of the diffracted lights 110 to 11 in FIG.
2 is a partially enlarged view of FIG. The 0th-order diffracted light 110 for recording, reproduction and AF is located at the center of the ± first-order diffracted lights 111 and 112 for AT and scans the center of the track T3. Shaded area 1
Reference numerals 13a, b, and c denote the strong power of the semiconductor laser 101 as 0.
A recording sequence by the next-order diffracted light 110, which is generally called a pit. Since the pits 113a, b, and c have different reflectivities from the periphery of the other recording rows, the weak light spot 110 is again used.
, The reflected light of the zero-order diffracted light 110 becomes pit 113
Modulated by a, b, and c to obtain a reproduced signal. Also, A
The ± first-order diffracted lights 111 and 112 for T are applied to the periphery of the recording row and to the tracking tracks tt3 and tt4, and the reflected light provides a tracking control signal.

FIG. 6 is a circuit diagram showing details of the photodetector 109 of FIG. 3 and a signal processing circuit. In FIG. 6, a photodetector 109 is a quadrant photosensor 114, photosensors 115 and 11,
It consists of a total of six optical sensors. The light spots 110a, 111a, and 112a are respectively shown in FIG.
(A), each diffracted light 110, 111, 112 in FIG.
Represents reflected light. The light spot 110a is condensed on the four-divided optical sensor 114, and the light spots 111a, 112a
Are focused on the optical sensors 115 and 116, respectively. The sensor output in each diagonal direction of the four-divided sensor 114 is
17 and 118 are added.

The outputs of the adders 117 and 118 are similarly added by the adder 121 and output as an information reproduction signal RF. That is, the information reproduction signal RF is transmitted to the four-division optical sensor 11.
4 corresponds to the sum total of the light spots 110a condensed at 4.
Further, the outputs of the adders 117 and 118 are subtracted by the differential circuit 120 to become a focus control signal Af. That is, the focus control signal Af corresponds to the difference between the sums of the four divided optical sensors 114 in the diagonal directions. Since the astigmatism method is well known in the literature, the description is omitted here.

The outputs of the optical sensors 115 and 116 are subtracted by a differential circuit 119 to become a tracking control signal At. Normally, the tracking control signal At is controlled so as to be zero, and tracking control for causing the light spot to follow the information track is performed. Further, the optical sensor 11
The outputs of the adders 5 and 116 and the outputs of the adders 117 and 118 are added by the adder 122 to form a focus light amount signal Pf. That is, the focus light amount signal Pf is
4. Light spot 11 focused on optical sensors 115 and 116
0a, 111a, and 112a.

Differential circuits 119 and 120, adder circuit 12
A gain switching signal is supplied to 1, 122 to perform gain switching for removing a modulation component due to modulation of the semiconductor laser during recording. When a light spot is accessed to a target track on the optical card 107, a tracking control signal At generated when the light spot crosses a track on the optical card is binarized by a comparator to generate a track crossing signal. In addition, a track access method is used in which the optical head and the optical card are relatively moved in a direction perpendicular to the track while counting the track crossing signal.

FIG. 7 is a block diagram showing the configuration of a conventional optical card recording / reproducing apparatus. 7, first, when the optical card 107 is inserted into the apparatus, it is detected by a sensor (not shown) and notified to the MPU 201. The MPU 201 controls a motor drive circuit (not shown) to drive the loading motor, thereby introducing the optical card 107 into the apparatus and mounting the optical card 107 on the carriage 202. Also, the MPU 201
Controls the VCM drive circuit 219 and the voice coil 218
The optical head 204 is driven to drive the optical head 204 to the home position HP, which is the left end of the entire scanning area of the optical card in FIG. The optical head 204 is as shown in FIG. After that, MPU20
Numeral 1 connects SW1 to the A side and D / A converter 221
Is supplied to the AT actuator driving circuit 216. The command value at this time is a value that does not cause a drive current to flow through the actuator 123 in the optical head 204, and 0 voltage is applied to the actuator 123 from the AT actuator drive circuit 216.

At the same time, the MPU 201
03, the semiconductor laser 101 is turned on, and the light spot from the optical head 204 is irradiated on the home position HP of the optical card 107. The reflected light from the optical card 107 is detected by the photodetector 109, and the signal processing circuit 205 generates a focus control signal Af based on the sensor output. The signal processing circuit 205 is the circuit shown in FIG. MPU2
In step 01, focus is pulled using the focus control signal Af so that the light beam is focused on the medium surface at the home position HP.

Next, the MPU 201 operates the carriage 202.
Is moved in the direction orthogonal to the track, and the optical head 204 accesses the target track of the optical card 107 for track access. Although there is no track between the home position HP and the recording area, the track access is performed as follows in order to relatively move the optical head 204 and the carriage 202 in this area. First, the MPU 201
Is the D / A converter 207 with SW2 connected to the B side.
Is given a fixed command value. The D / A converter 207 supplies a voltage signal corresponding thereto to the DC motor drive circuit 208,
The DC motor 209 is driven at a constant current. DC motor 2
09 is transmitted to the lead shaft 211 via the gear 210 and the lead pin 21 fixed to the carriage 202
By moving the carriage 2, the carriage 202 is moved in the track orthogonal direction.

Upon entering the recording area, a track crossing signal is obtained, and a track access is performed using the signal. That is, the tracking control signal At is generated by the signal processing circuit 205, and the tracking control signal At is
The value is converted to a track crossing signal. MPU201
Calculates the scanning speed based on the pulse interval of the track crossing signal, calculates the residual distance to the target track from the count value of the track crossing signal, and calculates the control value based on the obtained scanning speed and residual distance. Then, the speed of the DC motor 209 is controlled. The control value of the MPU 201 is the D / A converter 20
7, and is supplied to the DC motor drive circuit 220 to move the carriage 202 while controlling the speed.

When the optical head 204 reaches the target track, the MPU 201 switches SW1 to the B side, turns on the tracking servo, draws the light spot into the target track, and starts tracking control. When the tracking servo is turned on, the tracking control signal At is sent from the signal processing circuit 205 to the actuator 12 via the phase compensator 214 and the AT actuator driving circuit 216.
3 and enters a tracking state. Also, MPU
201 switches SW2 to the A side, supplies the tracking control signal At to the DC motor drive circuit 220 via the phase compensators 214 and 217, and performs double tracking servo. That is, since the objective lens 106 shifts due to skew of the optical card or the like, the carriage 202 is driven based on the tracking control signal, and double tracking servo is performed so that the objective lens 106 is located at the center.

When the track access is completed, M
The PU 201 controls the VCM drive circuit 219 to drive a voice coil motor including a voice coil 218 and a magnet 217. By driving the voice coil motor, the optical head 204 moves in the track direction, and the optical head 20 moves.
The light spot of No. 4 is scanned on the target track. At this time, the track number of the optical card is read, and if it is confirmed that the track is the target track, the optical head 204 is further scanned to record or reproduce information. When recording information, the laser drive circuit 203 drives the semiconductor laser 101 in accordance with a recording signal, and performs recording by scanning an intensity-modulated light beam on a target track. When reproducing recorded information, a target light track is scanned with a reproducing light beam, and recording is performed by performing predetermined signal processing using an information reproducing signal RF generated by a signal processing circuit 205 in a reproducing circuit (not shown). Reproduce information.

[0019]

As described above, in the information reproducing and recording operations of the optical information recording / reproducing apparatus, the objective lens 106 is controlled so that the center position of the objective lens 106 is maintained when skew occurs. Carriage 2
02 must follow smoothly. 8A shows the skew of the optical card, and FIG. 8B shows the moving distance of the objective lens with respect to the skew. If the optical card has a skew, the objective lens follows the skew, and tracking control cannot be performed if the optical card exceeds the movable range. Therefore, the carriage is moved by the double tracking servo.

However, in the above-described conventional apparatus, a starting current is required for the DC motor 209 for driving the carriage due to the influence of the static friction of the driving system and the like. Therefore, the DC motor is not started until the tracking control signal exceeds a certain value. A current higher than the current has flowed, and driving has been possible. For this reason, when skew occurs, the objective lens 106 cannot smoothly follow the center position so as to maintain the center position, information cannot be recorded correctly, or the quality of the information reproduction signal detected by the optical head deteriorates, There was a problem that information could not be reproduced correctly. In addition, by increasing the gain of the double tracking servo, the value of the tracking control signal with respect to the starting current can be reduced. However, if the gain is increased, the phase margin of the control system decreases, and the operation becomes unstable. There was a problem.

An object of the present invention is to provide an optical information recording / reproducing apparatus capable of smoothly moving an objective lens to the center thereof when a skew occurs in view of the above conventional problems.

[0022]

SUMMARY OF THE INVENTION It is an object of the present invention to irradiate a recording medium with a light beam from an optical head including an objective lens and a first actuator for driving the objective lens in a tracking direction, based on a tracking control signal. By performing the tracking servo so that the light beam follows the track by driving the first actuator,
In addition, by driving a second actuator that relatively moves the optical head and the recording medium in a track transverse direction based on a drive signal or a position signal of the objective lens, the objective lens is positioned at the center thereof. In an optical information recording / reproducing apparatus for performing double tracking servo, means for detecting a skew direction of a recording medium from a drive signal of the first actuator, an optical head and a recording medium in the same direction as the detected skew direction Means for applying an offset corresponding to a predetermined current value smaller than the starting current value to the drive signal of the second actuator in the direction in which the relative information moves relative to the second actuator. You.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the optical information recording / reproducing apparatus of the present invention. In FIG. 1, the same parts as those of the conventional apparatus of FIG. In the present embodiment, an adder 224 is connected between the phase compensator 214 of the tracking servo loop and the phase compensator 217 of the double tracking servo loop. D / A from MPU 201
The offset value is supplied to the converter 223 and the adder 224
, The offset value from the D / A converter 223 is added to the tracking control signal from the phase compensator 214,
It is configured to apply to a heavy tracking servo loop.

The offset value from the MPU 201 is a value corresponding to a predetermined current which is smaller than the starting current of the DC motor 209. When the skew occurs, the offset is applied so that the carriage 202 can smoothly follow. I have. Further, the MPU 201 includes the A / D converter 22.
2 captures a tracking control signal from the objective lens 1
06 is detected, and an offset is applied so that the carriage 202 moves in the same direction as the skew direction. Other configurations are the same as those of the apparatus shown in FIG.

Next, the operation of this embodiment will be described with reference to FIG. In FIG. 2, first, S1 to S6 are processes for detecting the skew direction of the inserted optical card, and S7 to S1.
8 is an actual recording / reproduction process. When the optical card 107 is inserted into the apparatus (S1), it is detected by a sensor (not shown) and notified to the MPU 201. The MPU 201 controls a motor drive circuit (not shown), drives the loading motor, introduces the optical card 107 into the apparatus, and mounts the optical card 107 on the carriage 202. Next, the MPU 201
After the M drive circuit 219 is controlled to drive the voice coil motor including the magnet 217 and the voice coil 218, the optical head 204 is positioned at the home position HP, which is the left end of the entire scanning area in FIG. , D
A constant command value is given to the / A converter 221.

This command value is supplied to the actuator drive circuit 21
6 is set to a value that does not cause a drive current to flow through the tracking actuator 123. At the same time, the MPU 201
To the A side, and the D / A converter 221
Is supplied to the actuator drive circuit 216, and a zero voltage is applied to the tracking actuator 123. In this state, the MPU 201 controls the laser drive circuit 203, drives the semiconductor laser 101 in the optical head 204 by the laser drive circuit 203, and transfers the light beam focused by the objective lens 106 to the home position HP of the optical card 107. Irradiation. At this time, the reflected light from the optical card 107 is detected by the photodetector 109, and the signal processing circuit 205 generates the focusing control signal Af and the focus light amount signal Pf shown in FIG. Optical head 2 using
The AF coil (not shown) in the drive unit 04 is driven to perform focusing (S2).

Next, the MPU 201 moves the carriage 202 in the cross-track direction to move the optical head 204 to a predetermined track. That is, the MPU 201 sets SW2 to B
Side to give a fixed command value to the D / A converter 207, and the D / A converter 207 outputs a voltage signal corresponding to the command value to the D / A converter 207.
The DC motor 209 is supplied to the C motor drive circuit 220 to drive the DC motor 209 at a constant current. The torque of the DC motor 209 is transmitted to the lead shaft 211 via the gear 210, and the lead pin 212 fixed to the carriage 202 is moved to move the carriage 202 on which the optical card is mounted in the track orthogonal direction. When a track crossing signal is obtained, the tracking control signal At output from the signal processing circuit 205 is binarized by the comparison circuit 213 to generate a track crossing signal, which is supplied to the MPU 201. The MPU 201 calculates the scanning speed from the pulse interval of the track crossing signal, and outputs a signal for controlling the speed to D / D.
The signal is output to the A converter 207 and the carriage 202 is controlled by the speed control.
To move. The MPU 201 counts the track crossing signal and moves the optical head 204 until it reaches a predetermined track (S3).

When the optical head 204 arrives at a predetermined track, the MPU 201 switches SW1 to the B side, performs tracking pull-in, and performs tracking servo for tracking to a predetermined track on the optical card 107 (S
4). At this time, SW2 remains connected to the B side,
It has not switched to the double tracking servo. Next, the MPU 201 controls the VCM drive circuit 219 to drive the voice coil motor of the magnetic circuit composed of the magnet 217 and the voice coil 218, thereby scanning the optical head 204, that is, moving the light beam in the track direction. Scanning is performed (S5).

Here, the scanning state of the light beam and the parallel state of the tracks on the optical card correspond to the skew angle θ as shown in FIG.
Is mounted on the carriage 202. When the light beam scans in the R direction in FIG. 8 in this state, the objective lens 106 shifts in the tracking direction as shown in FIG. 8B because the objective lens 106 follows the track by the tracking control. Here, simultaneously with scanning, the MPU 201 performs A / D conversion of the output of the phase compensator 214, which is a signal obtained by phase-compensating the tracking control signal, by the A / D converter 222, so that the moving direction (skew) of the objective lens 106 is changed. Direction) (S
6). In the case of FIG. 8, when scanning in the R direction is detected as the U direction, and when scanning in the L direction is detected as the D direction. Thus, the detection of the skew direction of the optical card is completed.

Next, when a recording or reproduction command is issued from the host computer (not shown) to the MPU 201 (S
7), the MPU 201 seeks to the target track in the same manner (S8), and upon arriving at the target track, SW1
To the B side to perform tracking servo (S
9). Also, the MPU 201 switches SW2 to the A side,
The signal from the phase compensator 214 is supplied to the phase compensator 217 to perform phase compensation for double tracking servo. Then, a signal is supplied from the phase compensator 217 to the DC motor drive circuit 220 via SW2, and the control enters the double tracking servo control state (S10).

Subsequently, the scanning direction of the optical head 204 is detected (S11), and the DC motor 209 is detected in accordance with the scanning direction.
An offset is applied to the drive current. In this case, when the scanning direction of the optical head 204 is the L direction, the objective lens 106 moves in the D direction.
2 applies a predetermined offset voltage corresponding to a predetermined current smaller than the starting current of the DC motor 209 to the output of the phase compensator 214 via the D / A converter 223 and the adder 224 in the direction of movement in the D direction. (S12). As a result, the DC motor drive circuit 220 sends the DC motor 209
Since a predetermined current smaller than the starting current is applied to
Even if the objective lens 106 starts to move in the D direction following the skew, the carriage 202 can be quickly moved in the D direction.

When the scanning direction of the optical head 204 is the R direction, the objective lens 106 moves in the U direction.
U201 applies a predetermined offset voltage corresponding to a predetermined current smaller than the starting current of the DC motor 209 in the direction in which the carriage 202 moves in the U direction to the phase compensator 214 via the D / A converter 223 and the adder 224. It is applied to the output (S13). Thus, even if the objective lens 106 starts to move in the U direction following the skew of the optical card 107, the carriage 202 can be quickly moved in the U direction.

Next, the MPU 201 operates the VCM driving circuit 21.
9 by driving the voice coil motor of the magnetic circuit composed of the magnet 217 and the voice coil 218, thereby scanning the optical head 204, that is, scanning the light beam in the track direction (S14). When the objective lens 106 shifts due to skew because the objective lens 106 follows the track by the tracking control during this scanning, the carriage 20 is moved by the double tracking servo.
2 is corrected so that the objective lens 106 is positioned at the center position (the center position of the movable range). At this time,
Since a predetermined current smaller than the starting current is applied to the DC motor 209, the correction can be started immediately.

Here, when information is reproduced, the information reproduction signal RF detected during scanning is input to a reproduction circuit (not shown), and the reproduction circuit performs predetermined signal processing, thereby recording information on the optical card 107. Is reproduced and output to the MPU 201. The track currently being scanned by the light beam can be known from the track number indicating the track position on the optical card 107 among the information written on the optical card 107. During this time, the double tracking servo operation is continued, and when skew occurs, correction is performed so that the objective lens 106 maintains the center position. When recording information, the information is recorded by irradiating a light beam modulated by a recording signal with a recording power (S15). When the recording or reproducing operation is completed and a command to eject the optical card 107 is issued (S16), the optical card 107 is ejected (S17), and all operations are terminated (S18). If there is no card ejection command in S16, the process returns to S7 and enters a standby state waiting for a recording or reproduction command from the host computer.

In the above embodiment, the DC motor 2
09, a predetermined offset voltage corresponding to a predetermined current value smaller than the starting current is applied. However, a starting current of the DC motor 209 is measured at the time of assembling adjustment of the device, and a predetermined current smaller than the starting current is measured. An offset value corresponding to the value may be stored in the non-volatile memory, and the offset value may be applied during operation of the device. By doing so, it is possible to reduce the machine difference between the apparatuses, and to perform the correction more smoothly.

FIG. 8 shows a case of skew. If the skew direction is reversed, an offset is applied in the direction in which the carriage 202 moves in the U direction when scanning in the L direction, and the offset is applied in the R direction. Carriage 202 when scanning
The offset may be applied in the direction in which D moves in the D direction. Further, a drive signal of the objective lens 106 is used as a drive signal of the DC motor 209 in the double tracking servo, but a drive current signal of the objective lens 106 and a position signal of the objective lens 106 in the tracking direction with respect to the optical head 204 are used. You can use it. Although the carriage 202 on which the optical card 107 is mounted is moved in the track orthogonal direction, the optical head 204 may be moved in the track orthogonal direction.
A voice coil motor may be used in place of 09.

[0037]

As described above, according to the present invention, the offset is applied to the drive signal of the second actuator in the direction in which the optical head and the recording medium move relatively in the same direction as the skew direction of the recording medium. Accordingly, even when the objective lens starts to move following the skew during the operation of the double tracking servo, the optical head and the recording medium start moving relatively quickly, and the objective lens smoothly follows the skew so as to maintain the center position. Information can be recorded / reproduced correctly.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the embodiment of FIG. 1;

FIG. 3 is a diagram illustrating an example of an optical system of a conventional optical card recording / reproducing apparatus.

FIG. 4 is a diagram showing a relationship between a scanning speed for a recording surface of an optical card and a recording area of the optical card.

FIG. 5 is a diagram showing a light spot on an optical card.

FIG. 6 is a circuit diagram showing an example of a signal processing circuit of a conventional optical card recording / reproducing device.

FIG. 7 is a block diagram showing a conventional optical card recording / reproducing apparatus.

FIG. 8 is a diagram showing the skew of the optical card and the amount of movement of the objective lens due to the skew.

[Explanation of symbols]

 106 Objective lens 107 Optical card 201 MPU 202 Carriage 203 Laser drive circuit 204 Optical head 205 Signal processing circuit 207,221,223 D / A converter 209 DC motor 216 Actuator drive circuit 219 VCM drive circuit 220 DC motor drive circuit 222 A / D converter 224 Adder SW1, SW2 switch

Claims (2)

[Claims] 1. An optical head including an objective lens and a first actuator for driving the objective lens in a tracking direction irradiates a recording medium with a light beam, and drives the first actuator based on a tracking control signal. Performs a tracking servo so that the light beam follows the track, and moves a second actuator for relatively moving the optical head and the recording medium in a direction transverse to the track based on a drive signal or a position signal of the objective lens. An optical information recording / reproducing apparatus that performs double tracking servo so that the objective lens is positioned at the center thereof by driving; a means for detecting a skew direction of a recording medium from a drive signal of the first actuator; The optical head and the recording medium move relatively in the same direction as the direction of the detected skew Means for applying an offset corresponding to a predetermined current value smaller than a starting current value to the drive signal of the second actuator in the direction. 2. The optical information recording / reproducing apparatus according to claim 1, wherein the offset value is measured at the time of assembling adjustment of the apparatus and stored in a storage unit.