JPH11185280A - Optical pickup device, optical recording medium drive unit provided with it, and adjusting method for optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable performing position adjustment of a condenser lens for an optical axis of a laser beam when manufactured. SOLUTION: An optical pickup device 1 is provided with a photodiode integrated circuit element (PDIC) 50 for detecting a signal receiving feed back luminous flux for detecting a tracking state in accordance with a laser beam with which an optical disk is irradiated. The PDIC 50 for detecting a signal outputs detecting signals E0 and F0 in accordance with received feedback luminous flux. An adjusting circuit 51 including a variable resistor VR is provided at an output side of an optical detecting section, detecting signals E0 and F0 for detecting a tracking state are varied by adjusting a resistor value of the variable resistor VR, and the prescribed detected signals E and F are outputted. A tracking coil 42 moves a condenser lens in the radial direction of an optical disk, based on the detected signals E and F, and compensates positional deviation of the condenser lens.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup device, an optical recording medium driving device using the same, and a method of adjusting the optical pickup device.

[0002]

2. Description of the Related Art An optical pickup device used for an optical recording medium driving device such as an optical disk drive device uses a laser beam to record and read information on an optical recording medium such as an optical disk or to detect a servo signal.

[0003] In recent years, with the demand for miniaturization, weight reduction, and cost reduction of optical pickup devices, research and development of optical pickup devices using a transmission type hologram element, which is a kind of diffraction element, have been conducted.

FIG. 9 is a schematic view of a conventional optical pickup device. This optical pickup device performs tracking servo using a three-beam method and focus servo using an astigmatism method.

In FIG. 9, a laser beam 2 emitted from a semiconductor laser element 21 passes through a transmission type three-division diffraction grating 23, and is divided into a zero-order diffracted light beam (main light beam) and a ± 1st-order diffracted light beam (sub light beam). The light beam is divided into book light beams and transmitted through the transmission hologram element 24.

The three light beams transmitted through the transmission type hologram element 24 are condensed by the condenser lens 6 on the optical disk 100 as a main spot and sub spots located on both sides thereof. This condenser lens 6 is
Thus, the optical disc 100 is movably supported in the radial direction (X-axis direction) of the optical disc 100 for the tracking operation, and is movably supported in the Y-axis direction for the focus operation.

FIG. 10 is a diagram showing a main spot and a sub spot formed on the optical disc 100. As shown in FIG. 10, the main spot M0 is a track TR to be reproduced.
, And the optical system of the optical pickup device is adjusted so that the sub spots S1 and S2 slightly scan the track TR on both sides of the main spot M0.

The three return light beams (reflected light beams) from the optical disk 100 are diffracted by the transmission hologram element 24 and detected by the signal detecting photodiode 33.

FIG. 11 shows a photodiode 33 for signal detection.
It is a schematic plan view which shows an example of (1). The signal detecting photodiode 33 includes a four-division light detecting unit 5 provided at the center for performing focus servo using the astigmatism method.
0a to 50d, and photodetectors 50e and 50f provided on both sides of the quadrant photodetectors 50a to 50d for performing tracking servo by the three-beam method. The main spot M0 is located at the center of the four-division light detection units 50a to 50d.
The return light beam (main light beam) corresponding to is incident on the photodetector 50.
Return light fluxes (sub-spots) 2a and 2b corresponding to the sub-spots S1 and S2 are incident on e and 50f, respectively.

The light detectors 50e and 50e of the photodiode 33 for detecting the signals on which the return light beams (sub-light beams) 2a and 2b are incident.
The tracking operation is performed as follows based on the detection signal from 50f.

FIG. 12 is a circuit diagram of each unit for performing a tracking operation of an optical disk drive device having an optical pickup device. In FIG. 12, the light detection units 50e and 5e of the signal detection photodiode 33 of the optical pickup device 1 are shown.
The detection signals E and F output from 0f are output to an EF processing unit 55 provided in the drive circuit unit 54 of the optical disk drive.
Is output to In the EF processing unit 55, the light detection unit 50
The tracking error signal TE of the following equation is obtained using the detection signals E and F of e and 50f.

TE = EF The tracking error signal TE is input to an operational amplifier 58 of a servo circuit 57 via a low-pass filter 56, amplified, and then amplified by an actuator 4 of the optical pickup device 1.
0 is provided to the tracking coil 42.

As shown in FIG. 9, the condenser lens 6 is supported by an actuator 40 so as to be movable in the radial direction (X-axis direction) of the optical disk 100. Actuator 4
Reference numeral 0 denotes a holder 41 for holding the condenser lens 6 and a holder 41
Tracking coil 4 which is connected to and can move in the radial direction
2 and a permanent magnet 4 separated from the tracking coil 42
4 is provided. Then, when a driving voltage is applied to the tracking coil 42, the condenser lens 6 is moved in the X-axis direction by receiving an electromagnetic force generated between the tracking coil 42 and the permanent magnet 44.

In FIG. 10, when the main spot M0 on the optical disc 100 is effectively tracked on the track TR to be reproduced, two sub spots S0
1 and S2 have the same light intensity when the return light beams 2a and 2b enter the light detection units 50e and 50f, respectively. For this reason, the tracking error signal TE output from the EF processing unit 55 becomes 0, and no drive voltage is applied to the tracking coil 42 of the actuator 40. For this reason, the condenser lens 6 maintains that state.

When the main spot M0 is shifted to either side of the track TR to be reproduced, the intensity of one of the returning light fluxes from the sub spots S1 and S2 increases.
Therefore, the detection signals E, F of the light detection units 50e, 50f
Differences occur. For this reason, the tracking error signal TE is output from the EF processing unit 55, amplified by the operational amplifier 58 of the servo circuit 57, and
, A condensing lens 6 is moved in the radial direction, and the position of the main spot M0 is corrected.

In recent years, miniaturization of the optical pickup device has been strongly desired, and each component of the optical pickup device has been reduced in size, and the diameter of the condenser lens 6 has also been reduced. For this reason, in the assembly process of the optical pickup device, it is difficult to accurately align and arrange the condenser lens 6 in the optical path of the laser light.

FIG. 13 is a schematic plan view showing a state in which laser light is incident on the condenser lens 6. In the optical pickup device, the semiconductor laser element 21, the three-division diffraction grating 23, the transmission hologram element 24, and the condenser lens 6 are formed in independent units, and the two are aligned and assembled. Therefore, at the time of assembly, FIG.
As shown in the figure, the condenser lens 6 and the two sub-beams 2 of the laser beam
The optical axes a and 2b may be displaced d along the radial direction (X-axis direction) of the optical disc 100 in some cases.

If the displacement d of the mounting position of the condenser lens 6 occurs, the following inconvenience occurs. In the optical disk drive, an operation of moving the condenser lens 6 by a certain distance in the radial direction of the optical disk 100 is performed, for example, to find the beginning of a song recorded on the optical disk 100. However, as shown in FIG. 13, a deviation d between the condenser lens 6 and the optical axes of the sub-beams 2a and 2b of the laser light at the time of assembly.
When the condenser lens 6 is moved for the cueing operation, the amount of light passing through the condenser lens 6 varies depending on the moving direction. When the condenser lens 6 moves to one side, the amount of light passing through the condenser lens 6 is further reduced, and the output of the tracking error signal based on the sub-beam passing through the condenser lens 6 is reduced. As a result, an effective tracking operation cannot be performed.

FIG. 14 is a diagram showing a change in the tracking error signal when the condenser lens is moved. The horizontal axis in FIG. 14 indicates the moving direction and the moving distance of the condenser lens 6, and the vertical axis indicates the tracking error signal TE. In FIG. 14, the condenser lens 6 in the radial direction of the optical disc 100 is
Is coincident with the optical axis of the laser beam, a symmetrical distribution of the tracking error signal TE0 as shown by the dotted line is obtained when the condenser lens 6 is moved. On the other hand, when the center of the condenser lens 6 and the optical axis of the laser beam are shifted, an asymmetric distribution of the tracking error signal TE1 is obtained depending on the moving direction of the condenser lens 6. Then, at the moving position on one side of the condenser lens 6, a portion where the tracking error signal TE1 is lower than the output value A required for tracking occurs, and the cueing operation cannot be performed accurately.

Therefore, conventionally, an offset circuit 59 is provided on one input side of the operational amplifier 58 of the servo circuit 57 in order to correct the displacement of the condenser lens 6 with respect to the optical axis of the laser light. The process of correcting the displacement of the condenser lens 6 using the offset circuit 59 is performed as follows in a state where the optical pickup device is incorporated in the optical disk drive.

First, the condenser lens 6 is moved by a predetermined distance, for example, 400 μm, in the radial direction of the optical disc 100 toward the center and the outer circumference, respectively, and the value of the tracking error signal TE at that time is detected. As shown in FIG. 14, when the center of the condenser lens 6 and the optical axis of the laser beam are shifted, the voltage of the tracking error signal when the condenser lens 6 moves to the center side and the outer periphery side is different. Therefore, the focusing lens 6 is moved so that the tracking error signal when the focusing lens 6 moves to the center side and the outer periphery side becomes equal.
Is moved (the position of the condenser lens 6 when the tracking operation is not performed).

That is, the resistance value of the variable resistor 60 of the offset circuit 59 is adjusted, a driving voltage is applied to the tracking coil 42, and the origin position of the focusing lens 6 is moved in the radial direction of the optical disc 100. Further, the focusing lens 6 is moved from the moving origin position of the focusing lens 6 to the optical disc 1.
00 along the radial direction by a predetermined distance toward the center and the outer periphery, and the tracking error signal TE at that time is moved.
Detect the value of. Then, the adjustment of the variable resistor 60 of the offset circuit 59 ends when the detected value of the tracking error signal TE becomes equal when moving to the center side and the outer circumference side. This makes it possible to correct the deviation between the condenser lens 6 and the optical axis of the laser light in the radial direction of the optical disc 100.

[0023]

However, there are cases where the optical pickup device is manufactured and sold as a single unit. In this case, the manufacturers of the optical pickup device and the optical disk drive device using the optical pickup device are different. For this reason, it is necessary for the manufacturer of the optical disk drive device or the like to adjust the position shift of the condenser lens of the optical pickup, and the assembly and adjustment work becomes complicated for these manufacturers.

An object of the present invention is to provide an optical pickup device capable of adjusting the position of a condenser lens with respect to the optical axis of a laser beam during manufacturing, an optical recording medium driving device provided with the same, and a method of adjusting the optical pickup device. To provide.

[0025]

SUMMARY OF THE INVENTION An optical pickup device according to the present invention irradiates an optical recording medium with a light beam through a condensing lens, and detects a tracking state detection signal based on a feedback light beam from the optical recording medium. Is provided with an adjustment unit capable of changing the tracking detection signal.

In the optical pickup device according to the present invention, the tracking state detection signal can be changed by the adjusting unit. Therefore, by utilizing the function that can move the condenser lens based on the tracking state detection signal and adjusting the tracking state detection signal, the state in which the center of the condenser lens deviates from the optical axis of the light beam can be corrected. Can be corrected. Moreover, since the adjustment unit is provided in the optical pickup device itself, the adjustment operation of the adjustment unit can be performed at the stage of assembling the optical pickup device. This makes it possible to omit an adjustment operation for correcting a positional shift of the central portion of the condensing lens of the optical pickup device in a device incorporating the optical pickup device.

In particular, there is provided a lens drive section for moving the condenser lens in the radial direction of the optical recording medium in response to a predetermined signal based on the tracking state detection signal changed by the adjustment section.

The lens drive unit moves the condenser lens in the radial direction of the optical recording medium in response to a predetermined signal based on the tracking state detection signal changed by the adjustment unit. This makes it possible to correct the positional shift of the central portion of the condenser lens with respect to the optical axis of the light beam.

In particular, it is preferable that the tracking state detection signal is composed of a plurality of detection signals, and the adjusting unit includes a signal variable circuit for changing the plurality of detection signals.

In this case, a desired signal can be generated by appropriately changing the plurality of detection signals by the signal variable circuit. This desired signal is a bias signal for moving the condenser lens in the radial direction of the optical recording medium during operation of the optical pickup device. This makes it possible to correct the positional shift of the central portion of the condenser lens with respect to the optical axis of the light beam.

An optical pickup device according to the present invention is an optical pickup device capable of detecting a tracking state of a light beam for reading information from an optical recording medium, comprising a light source for emitting a light beam, and a light beam emitted from the light source. A diffraction element for splitting a plurality of light beams for tracking state detection from
A condensing lens that is provided movably in the radial direction of the optical recording medium and condenses a plurality of light beams split by the diffractive element on the optical recording medium, and a plurality of tracking state detection light condensed on the optical recording medium A photodetector having a plurality of light receiving sections for respectively receiving a plurality of return light fluxes based on the light flux and outputting a detection signal according to the amount of received light; and a plurality of detection signals output from the plurality of light receiving sections of the photodetector. An adjustment circuit that can be changed, and a lens drive unit that moves the condenser lens in the radial direction in response to a predetermined signal based on a plurality of detection signals adjusted by the adjustment circuit.

In the optical pickup device according to the present invention, a plurality of detection signals for detecting the tracking state are changed by the adjustment circuit, and the condenser lens can be moved by a predetermined signal based on the changed detection signal. For this reason, by adjusting the adjustment circuit so as to change the detection signal in accordance with the shift amount of the central portion of the condenser lens with respect to the optical axis of the light beam, the displacement of the condenser lens can be corrected.

Further, since the adjustment circuit is provided in the optical pickup device itself, the adjustment operation of the adjustment circuit can be performed at the stage of assembling the optical pickup device. This makes it possible to omit an adjustment operation for correcting a positional shift of the condenser lens of the optical pickup device in a device incorporating the optical pickup device.

In particular, it is preferable that the adjustment circuit includes a variable resistor that changes a plurality of detection signals output from a plurality of light receiving units of the photodetector.

In this case, by adjusting the resistance value of the variable resistor, it is possible to easily change the predetermined signal given to the lens driving unit to correct the position shift of the condenser lens.

In particular, a wiring portion for extracting signals from a plurality of light receiving portions of the photodetector may be further provided, and the variable resistor may be arranged in the wiring portion.

In this case, by adjusting the resistance value of the variable resistor disposed in the wiring section, a predetermined signal given to the lens driving section can be easily changed to correct the position shift of the condenser lens. .

In particular, the wiring portion is preferably formed on a flexible substrate. In this case, due to the flexibility of the flexible substrate, the degree of freedom in mounting the wiring portion in the optical pickup device is improved, and the size of the optical pickup device can be reduced.

In particular, the photodetector includes a plurality of amplifying sections provided corresponding to the plurality of light receiving sections and amplifying the difference between the detection signal output from the corresponding light receiving section and the reference signal, respectively. It is preferable to include a variable resistor that changes a reference signal supplied to at least one of the plurality of amplifying units.

In this case, by adjusting the variable resistor to change the reference signal, it is possible to easily change the predetermined signal to be supplied to the lens driving unit and correct the position shift of the condenser lens.

In particular, it is preferable that the light receiving section and the plurality of amplifying sections are formed on one chip. In this case, it is suitable for miniaturization.

An optical recording medium driving device according to the present invention comprises: a rotation driving section for rotating an optical recording medium; an optical pickup device according to any one of the above-mentioned inventions; and moving the optical pickup device in a radial direction of the optical recording medium. And a signal processing unit for processing an output signal from the optical pickup device.

In the optical recording medium driving device according to the present invention, an optical pickup device adjusted so as to output a tracking signal for correcting the displacement of the condenser lens is incorporated. The work of adjusting the displacement of the optical lens becomes unnecessary, and the work of assembling the optical recording medium driving device becomes easy.

In the method for adjusting an optical pickup device according to the present invention, a light source for emitting a light beam, a diffractive element for dividing a plurality of light beams for tracking state detection from the light beam emitted from the light source, and the diffractive element A condenser lens for condensing a plurality of light beams on the optical recording medium, a lens driving unit for moving the condensing lens in a radial direction of the optical recording medium, and a plurality of light beams for tracking state detection condensed on the optical recording medium And a photodetector having a plurality of light receiving units that output a plurality of detection signals according to the amount of received light, respectively, in the optical pickup device, An adjustment method for an optical pickup device for correcting a positional shift of a central portion of a condenser lens with respect to an optical axis of a light beam, wherein the optical pickup device outputs light from a plurality of light receiving units. An adjustment circuit capable of changing each detection signal to be generated, and generating a drive signal for moving the condenser lens in the radial direction based on the detection signal output from the photodetector via the adjustment circuit. After connecting the drive circuit to the lens drive unit of the optical pickup device and moving the condenser lens in the radial direction by changing the detection signal using the adjustment circuit, while moving the condenser lens a predetermined distance in the radial direction By observing the change of the detection signal,
This is to correct the positional deviation of the central portion of the condenser lens with respect to the optical axis of the plurality of light beams in the radial direction of the optical recording medium.

In the method for adjusting an optical pickup device according to the present invention, a drive circuit prepared in advance is connected to a lens drive unit of the optical pickup device, and a plurality of detection signals for detecting a tracking state are changed by the adjustment circuit. The condenser lens is moved by a predetermined signal based on the detected signal. Then, from the state where the condenser lens is moved, the condenser lens is reciprocated a predetermined distance in the radial direction in order to further inspect the state of the displacement of the condenser lens, and a detection signal at that time is obtained. Observe the changes. Then, the adjustment circuit adjusts the detection signal so that the detection signal has a desired value. As described above, by adjusting the adjustment circuit so as to change the detection signal in accordance with the shift amount of the mounting position of the condenser lens with respect to the optical axis of the light beam, it is possible to correct the displacement of the central portion of the condenser lens. it can.

In addition, since the adjustment circuit is provided in the optical pickup device itself, the adjustment operation of the adjustment circuit can be performed at the stage of assembling the optical pickup device.
This makes it possible to omit the adjustment operation for correcting the positional deviation of the central portion of the condensing lens of the optical pickup device in the device incorporating the optical pickup device.

[0047]

FIG. 1 is a side view showing the structure of an optical pickup device according to a first embodiment of the present invention.
FIG. 2 is an exploded perspective view of a light emitting and receiving unit of the optical pickup device of FIG. 1 and 2, the X-axis direction indicates the radial direction of the optical disk 100, the Y-axis direction indicates the direction perpendicular to the recording surface of the optical disk 100, and the Z-axis direction indicates YZ.
Indicates the direction perpendicular to the plane. In FIG. 1, for convenience of illustration, the light emitting and receiving unit is shown rotated by 90 degrees around the Y axis.

In FIGS. 1 and 2, the optical pickup device comprises a housing (not shown) including a condenser lens 6 and a light emitting / receiving unit including a semiconductor laser element 21, a three-division diffraction grating 23 and a transmission hologram element 24. It is formed by being integrally combined.

The light emitting and receiving unit has a support member 10.
The support member 10 includes an insulative molded body 11 in which the lead frame 12 and the pair of leads 13a and 13b are made of resin.
It is integrated. The lead frame 12 and the leads 13a, 13a
A recess 14 is provided that opens from one end face 15 to the other end face 16 so that the surface of b is exposed.

A conductive submount (heat sink) 20 is attached to one end surface 15 of the lead frame 12 exposed in the concave portion 14 of the insulating mold body 11, and is electrically connected to the lead frame 12. I have. A monitor photodiode 22 is formed on a part of the upper surface of the conductive submount 20. A monitor photodiode 22 is provided on the upper surface of the submount 20.
A semiconductor laser device 21 is mounted in front of the device. The semiconductor laser element 21 emits laser light from the front end face and the rear end face, respectively, and the laser light emitted from the rear end face is received by the monitoring photodiode 22 as monitor light.

In the center of the lead frame 12 in the concave portion 14 of the insulating mold body 11, a three-divided diffraction grating 23 is provided. The diffraction grating surface of the three-division diffraction grating 23 divides the laser light emitted from the front end face of the semiconductor laser device 21 into 0th-order, + 1st-order, and -1st-order diffracted light beams.

Further, the concave portion 14 of the insulating mold body 11
Inside, a transmission type hologram element 24 is arranged on the other end face 16 side on the lead frame 12. The hologram surface 25 of the transmission hologram element 24 transmits the 0th-order, + 1st-order, and -1st-order diffracted light beams from the three-division diffraction grating 23, and also transmits the optical recording medium 10 such as an optical disk.
Diffracts the return light beam from zero. Further, in the concave portion 14 of the insulating mold body 11, on the lead frame 12, the stray light shielding plate 1 for shielding the emitted light beam from the semiconductor laser element 21 and the returned light beam from the three-division grating 23 from each other.
7 are arranged.

Further, one end face 1 of the insulating mold body 11
The flexible substrate 30 is attached to the fifth side.
On the flexible substrate 30, a conductive wiring pattern is formed on the surface of a polyimide resin plate, and has a wiring portion 31 and a fixing portion 32. A photodiode integrated circuit element (hereinafter, referred to as PDIC) 50 for signal detection, which functions as a photodetector, is attached to the surface (wiring pattern formation surface) of the wiring portion 31 of the flexible substrate 30. Also, the PDI of the wiring portion 31 of the flexible substrate 30
On both sides of C50, a circular screw through hole 34a and an oval screw through hole 35b are formed. Further, a holding plate 36 is attached to the back surface of the flexible substrate 30.

The surface of the fixing portion 32 of the flexible board 30 is fixed to the pair of leads 13a and 13b and the lower surface of the lead frame 12 by soldering or the like. The wiring portion 31 of the flexible substrate 30 is bent upward so as to be perpendicular to the upper surface of the lead frame 12. In this state, the screws 37 and 38 are screwed into screw holes (not shown) through the screw through holes 34a and 34b, and the wiring portion 31 is attached to the end face 15 of the insulating mold body 11.

The housing is provided with a reflection mirror 5, a condenser lens 6, and an actuator 40.
The reflecting mirror 5 transmits through the transmission type hologram element 24.
The diffracted light flux of the book is reflected vertically upward, and the return light flux from the optical disc 100 is reflected in the horizontal direction and guided to the transmission hologram element 24 side.

The condenser lens 6 condenses the three diffracted light beams reflected by the reflection mirror 5 on the optical disc 100 to form a main spot and two sub-spots on both sides thereof.

The actuator 40 has a holder 41, a tracking coil 42, a yoke 43 and a permanent magnet 44. When a drive signal (tracking error signal) is given to the tracking coil 42, the fixed yoke 43
Permanent magnet 44 and tracking coil 4 attached to
Receiving the electromagnetic force generated between the tracking coil and the tracking coil
2 moves the condenser lens 6 via the holder 41 to the optical disc 10
0 in the radial direction (X-axis direction).

FIG. 3 is a plan view of a flexible substrate used in the optical pickup device of FIG. 1, and FIG. 4A is a diagram showing an example of wiring of the flexible substrate of FIG.
(B) PDIC arranged on the flexible substrate of FIG.
3 is a plan view of a light receiving section of FIG.

As shown in FIG. 3, the flexible substrate 30
Are a plurality of conductive wiring layers L on the polyimide resin plate 45.
1 to L10 are formed. As shown in FIGS. 3 and 4, the wiring layers L1 to L6 are connected to the output electrodes of the signal detecting PDIC 50 via bonding wires, and the wiring layer L7 is connected to the GND electrode of the signal detecting PDIC 50. The wiring layer L8 is connected to the anode of the monitoring photodiode 22 via the lead 13b and the bonding wire, and the wiring layer L9 is connected to the anode of the semiconductor laser device 22 via the lead 13a and the bonding wire 19. L10 is the lead frame 12
Are commonly connected to the cathodes of the semiconductor laser element 21 and the monitoring photodiode 22 via the.

On both sides of the signal detecting PDIC 50, a circular screw through hole 34a and an oval screw through hole 35 are formed.
b is formed. Further, in FIG. 4, a signal detection PDIC 50 is provided with a four-division light detection unit 5 provided at the center for performing focus servo using the astigmatism method.
0a to 50d, photodetectors 50e and 50f provided on both sides of the quadrant photodetectors 50a to 50d for performing tracking servo by the three-beam method, and operational amplifiers (operational amplifiers) 52a to 52f. 4 division photodetector 5
The detection signals 0a to 50d are output through four of the operational amplifiers 52a to 52d and the wiring layers L1 to L6, and the detection signals of the tracking servo light detection units 50e and 50f are output from the operational amplifiers 52e and 52f and the remaining two. Output through the wiring layer. Also, the light detection units 50e, 50f
An adjustment circuit 51 (see FIG. 5), which will be described later, is connected to the wiring layer connected to.

FIG. 5 is a diagram showing a circuit configuration of each unit for performing the tracking operation of the optical pickup device. The tracking operation of the optical pickup device 1 is performed in an inspection process of the optical pickup device.
4 is performed. As shown in FIG. 5, in the optical pickup device 1, the light detection unit 5 of the signal detection PDIC 50 is provided.
An adjustment circuit 51 is provided in the middle of the wiring layer that outputs the detection signals 0e and 50f. The adjustment circuit 51 includes the light detection unit 5
And resistors R1 and R2 inserted in series in a wiring layer connected to the wiring layers 0e and 50f, and a variable resistor V inserted between both wiring layers.
R. The movable terminal of the variable resistor VR is the power supply voltage V
Connected to cc. Then, by changing the resistance value of the variable resistor VR, the detection signal E0 output from the light detection unit 50e of the signal detection PDIC 50 and the detection signal F0 output from the light detection unit 50f are changed. Thus, a desired detection signal can be generated and output in order to adjust the optical axis shift of the condenser lens 6 described later.

In this embodiment, the semiconductor laser element 2
1 corresponds to the light source of the present invention, the three-division diffraction grating 23 corresponds to a diffraction element, the PDIC for signal detection 50 corresponds to a photodetector, and the adjustment circuit 51 corresponds to an adjustment unit and an adjustment circuit.

In the optical pickup device having the above structure, the housing on which the condenser lens 6 is mounted and the light emitting and receiving unit on which the semiconductor laser element 21 and the like are mounted are aligned and integrally assembled. In the assembling process of the optical pickup device, the mounting position of the condenser lens 6 with respect to the optical axis of the laser beam emitted from the semiconductor laser element 21 may be shifted in the radial direction (X-axis direction) of the optical disc 100 due to an assembling error. is there.

Therefore, in the optical pickup device 1, as shown in FIG. 5, the resistance value of the variable resistor VR of the adjusting circuit 51 provided in the optical pickup device 1 is adjusted using the inspection drive circuit 64. The position shift of the condenser lens 6 is corrected.

First, the optical pickup device 1 is attached to a predetermined position of an inspection device (not shown), and the semiconductor laser element 21 irradiates a laser beam onto the optical disk 100 to reproduce a main spot for reproduction and a tracking state detection 2. Form two minor spots. The signal detection PDIC 50 receives the return light beam corresponding to the main spot and the return light beam corresponding to the sub spot, and detects detection signals E0 and F corresponding to the amount of received light.
Outputs 0. The detection signals E0 and F0 are supplied to the adjustment circuit 51.
, The detection signals E and F are output from the output terminal of the flexible substrate 30 to the inspection drive circuit 64.

The test drive circuit 64 includes an EF processing unit 65,
It has a low-pass filter 66 and an operational amplifier 67. The EF processing unit 65 calculates a tracking error signal TE (= EF) based on the detection signals E and F output from the optical pickup device 1. In this inspection step, the tracking error signal TE is not a signal for actually performing the tracking, but a bias voltage for forcibly moving the condensing lens 6 in which the positional deviation has occurred in the radial direction of the optical disc 100. 42. This tracking error signal TE passes through the low-pass filter 66, is amplified by the operational amplifier 67, and is provided to the tracking coil 42. Thereby, the condenser lens 6 moves in the radial direction of the optical disc 100 according to the tracking error signal TE.

The adjustment of the adjustment circuit 51 is performed as follows. A constant drive signal is given to the tracking coil 42 to move the condenser lens 6 along the radial direction of the optical disc 100 by a certain distance, for example, 400 μm, toward the center and the outer circumference, and the tracking error signal TE at that time is compared. Then, as shown in FIG. 14, if the values of the tracking error signals TE when moving in the opposite directions are different, the inspector adjusts the resistance value of the variable resistor VR of the adjustment circuit 51 and outputs the detection signal E0. , F0 to make the value of the tracking error signal TE equal.
Thus, the adjustment circuit 51 is provided in the tracking coil 42.
As a result, a drive signal to which a constant bias voltage is added is applied, and the displacement of the condenser lens 6 is corrected.

FIG. 6 is a circuit diagram of an adjustment circuit according to a second embodiment of the present invention. In the optical pickup device shown in FIG. 6, an operational amplifier 52e for amplification is provided on the output side of the photodetector 50e in the PDIC 50 for signal detection, and an operational amplifier 52f for amplification is provided on the output side of the photodetector 50f. An operational amplifier 52e on the side of one of the light detection units 50e
The reference voltage Vref is input to one of the input sections. The difference between the detection signal of the light detection unit 50e and the reference voltage Vref is amplified from the operational amplifier 52e and output as a detection signal E.

An adjustment circuit 53 is connected to one input side of the operational amplifier 52f. The adjustment circuit 53 is connected to the power supply voltage Vcc, and can change the voltage of the reference signal input to the operational amplifier 52f by adjusting the variable resistor 53a. The operational amplifier 52f amplifies the difference between the detection signal of the light detection unit 50f and the reference signal from the adjustment circuit 53 and outputs the result as a detection signal F. The adjustment circuit 53 can change the value of the detection signal F. This makes it possible to add a bias voltage to the tracking error signal TE calculated by the EF processing unit 55 to correct the position shift of the condenser lens 6.
As a result, the condenser lens 6 is moved in the radial direction by the drive signal supplied to the tracking coil 42, and the positional deviation between the condenser lens 6 and the optical axis of the laser light in the radial direction is corrected.

The photodetectors 50a to 50a in this embodiment
50f and the operational amplifiers 52a to 52f (amplifying units) are formed on one chip.

The operational amplifiers 52e and 52 of the present embodiment
f corresponds to the amplification section of the present invention. FIG. 7 is a plan view showing another example of the PDIC 50 for signal detection. The light receiving section 65 of the signal detection PDIC is composed of a pair of light detection sections 66a and 66b for focus servo and these light detection sections 6a and 66b.
A pair of tracking servo photodetectors 66c and 66d are provided so as to be opposed to 6a and 66b.
Further, according to the signal detection photodiode 65,
The hologram surface of the transmission hologram element 24 is divided into four regions having different shapes. Signal detection photodiode 6 having such photodetectors 66a to 66d
5 can also be provided with the adjusting circuits 51 and 53 according to the first and second embodiments.

As described above, the optical pickup devices according to the first and second embodiments include the adjustment circuits 51 and 53,
Since the displacement of the condenser lens 6 can be corrected by itself, the manufacturer of the device incorporating the optical pickup device can
The operation of adjusting the displacement of the condenser lens of the optical pickup device becomes unnecessary.

FIG. 8 is a block diagram showing the configuration of an optical recording medium driving device 70 using the optical pickup device 1 of the first or second embodiment. 8 is an optical disk drive for reading information from the optical disk 100. The optical recording medium driving device 70 includes an optical pickup device 1, a motor 71, a feed motor 72, a rotation control system 73, a signal processing system 74, and a pickup control system 7.
5, including a feed motor control system 76 and a drive controller 77.

The motor 71 rotates the optical disc 100 at a predetermined speed. The rotation control system 73 controls the rotation operation of the motor 71. The feed motor 72 moves the optical pickup device 1 in the radial direction of the optical disc 100. The feed motor control system 76 controls the operation of the feed motor 72. The optical pickup device 1 irradiates a laser beam to the optical disc 100 and receives a return light beam from the optical disc 100. The pickup control system 75 controls the light emitting / receiving operation of the optical pickup device. The signal processing system 74
Upon receiving a detection signal from the signal detection PDIC 50 of the optical pickup device 1, a reproduction signal, a focus error signal, and a tracking error signal are calculated, the reproduction signal is supplied to the drive controller 77, and the focus error signal and the tracking error signal are transmitted to a pickup control system. Give 75. The drive controller 77 controls a rotation control system 73, a signal processing system 74, a pickup control system 75, and a feed motor control system 76 according to a command given via a drive interface 78, and outputs a reproduction signal via the drive interface 78. I do.

In this embodiment, the motor 71 and the rotation control system 73 correspond to a pickup drive unit, and the signal processing system 74
Corresponds to the signal processing unit.

In the optical recording medium driving device 70 shown in FIG. 8, the optical pickup device 1 of the first or second embodiment is used. Therefore, it is not necessary to adjust the displacement of the condenser lens 6, and the assembling work is simplified.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a configuration of an optical pickup device according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of a light emitting and receiving unit of the optical pickup device of FIG.

FIG. 3 is a plan view of a flexible substrate of the optical pickup device of FIG.

4A is a circuit diagram of the flexible substrate of FIG. 3 and FIG. 4B is a plan view of a light receiving unit of the PDIC attached to the flexible substrate.

5 is a circuit diagram of each unit for performing a tracking operation of the optical pickup device of FIG. 1;

FIG. 6 is a circuit diagram near an adjustment circuit of an optical pickup device according to a second embodiment of the present invention.

FIG. 7 is a plan view showing another example of the light receiving unit of the signal detection PDIC.

FIG. 8 is a block diagram of an optical recording medium driving device according to the present invention.

FIG. 9 is a schematic diagram showing a configuration of a conventional optical pickup device.

FIG. 10 is a schematic plan view showing a light condensing state on an optical disc.

FIG. 11 is a plan view of a signal detection photodiode.

FIG. 12 is a circuit diagram of each unit that performs a tracking operation of an optical disk drive device including a conventional optical pickup device.

FIG. 13 is a schematic plan view showing the state of incidence of laser light on the condenser lens.

FIG. 14 is a diagram illustrating a change in a tracking error signal when the condenser lens is moved.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical pick-up apparatus 5 Reflection mirror 6 Condensing lens 21 Semiconductor laser element 23 Three-division grating 24 Transmission hologram element 30 Flexible substrate 31 Wiring part 40 Actuator 42 Tracking coil 50 Signal detection PDIC (photodetector) 50a-50f Photodetection sections 51, 53 Adjustment circuits 52a to 52f Operational amplifiers (amplifiers) 53a, VR Variable resistors 54 Drive circuit sections 55 EF processing sections 56 Low-pass filters

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[Procedure amendment]

[Submission date] May 1, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0047

[Correction method] Change

[Correction contents]

[0047]

FIG. 1 is a side view showing the structure of an optical pickup device according to a first embodiment of the present invention.
FIG. 2 is an exploded perspective view of a light emitting and receiving unit of the optical pickup device of FIG. 1 and 2, the X-axis direction indicates the radial direction of the optical disc 100, the Y-axis direction indicates the direction perpendicular to the recording surface of the optical disc 100, and the Z-axis direction indicates XY.
Indicates the direction perpendicular to the plane. In FIG. 1, for convenience of illustration, the light emitting and receiving unit is shown rotated by 90 degrees around the Y axis.

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

FIG. 3

[Procedure amendment 3]

[Document name to be amended] Drawing

[Correction target item name] Fig. 9

[Correction method] Change

[Correction contents]

FIG. 9

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Atsushi Tajiri 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Kazushi Mori 2-chome Keihanhondori, Moriguchi-shi, Osaka No.5-5 Sanyo Electric Co., Ltd. (72) Inventor Akira Ibaraki 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (11)

[Claims] 1. An optical pickup device for irradiating a light beam onto an optical recording medium through a condenser lens and outputting a tracking state detection signal based on a feedback light beam from the optical recording medium, wherein the tracking state detection signal is changed. An optical pickup device, comprising an adjustment unit capable of performing the adjustment. 2. A method according to claim 1, further comprising the step of: moving the condenser lens in a radial direction of the optical recording medium in response to a predetermined signal based on the tracking state detection signal changed by the adjustment unit. The optical pickup device according to claim 1, wherein: 3. The optical pickup device according to claim 1, wherein the tracking state detection signal includes a plurality of detection signals, and the adjustment unit includes a signal variable circuit that changes the plurality of detection signals. . 4. An optical pickup device capable of detecting a tracking state of a light beam for reading information from an optical recording medium, comprising: a light source for emitting a light beam; and a tracking state detecting device for detecting a tracking state from the light beam emitted from the light source. A diffractive element for splitting a plurality of light beams of the optical recording medium, and a condenser lens provided so as to be movable in a radial direction of the optical recording medium, for condensing the plurality of light beams split by the diffractive element on the optical recording medium, A photodetector having a plurality of light receiving units that respectively receive a plurality of return light fluxes based on the plurality of light fluxes for tracking state detection collected on the optical recording medium and output a detection signal according to a received light amount; An adjustment circuit capable of changing a plurality of detection signals output from the plurality of light receiving units of the photodetector; and the plurality of detection circuits adjusted by the adjustment circuit. An optical pickup device comprising: a lens driving unit that moves the condensing lens in the radial direction in response to a predetermined signal based on the output signal. 5. The optical pickup device according to claim 4, wherein the adjustment circuit includes a variable resistor that changes the plurality of detection signals output from the plurality of light receiving units of the photodetector. . 6. The light according to claim 5, further comprising a wiring section for extracting signals from the plurality of light receiving sections of the photodetector, wherein the variable resistor is disposed in the wiring section. Pickup device. 7. The optical pickup device according to claim 6, wherein the wiring portion is formed on a flexible substrate. 8. The photodetector further includes a plurality of amplifying units provided corresponding to the plurality of light receiving units and amplifying a difference between a detection signal output from the corresponding light receiving unit and a reference signal, respectively. 5. The optical pickup device according to claim 4, wherein the adjustment circuit includes a variable resistor that changes the reference signal applied to at least one of the plurality of amplifying units. 9. The light receiving unit and the plurality of amplifying units are one.
9. The optical pickup device according to claim 8, wherein the optical pickup device is formed on one chip. 10. A rotation drive unit for rotating an optical recording medium, an optical pickup device according to claim 1, and a pickup drive unit for moving the optical pickup device in a radial direction of the optical recording medium. And a signal processing unit for processing an output signal from the optical pickup device. 11. A light source for emitting a light beam, a diffraction element for dividing a plurality of light beams for tracking state detection from the light beam emitted from the light source, and optical recording of the plurality of light beams split by the diffraction element. A focusing lens for focusing on a medium, a lens driving unit for moving the focusing lens in a radial direction of the optical recording medium, and a plurality of light fluxes for tracking state detection focused on the optical recording medium. A light detector having a plurality of light receiving units that respectively receive a plurality of return light beams and output a plurality of detection signals according to the amount of received light, wherein the plurality of light beams are output in a radial direction of the optical recording medium. An adjustment method of an optical pickup device for correcting a positional shift of a central portion of the condenser lens with respect to an optical axis of a light beam, wherein the optical pickup device includes An adjustment circuit capable of changing each detection signal output from the optical unit is provided, and the condenser lens is moved in the radial direction based on the detection signal output from the photodetector via the adjustment circuit. A drive circuit for generating a drive signal for movement is connected to the lens drive section of the optical pickup device, and the converging lens is moved in the radial direction by changing the detection signal using the adjustment circuit. Then, by observing a change in the detection signal while moving the condensing lens a predetermined distance in the radial direction, the center of the condensing lens with respect to the optical axis of the plurality of light beams in the radial direction of the optical recording medium. A method for adjusting an optical pickup device, comprising: correcting a positional shift of a unit.