JPH05217174A - Optical pickup device - Google Patents

Abstract

PURPOSE:To eliminate the displacement of the optical axis of an object lens when the object lens is moved to its focusing direction. CONSTITUTION:An adjusting mechanism 50 which adjusts the direction of the dividing line LV of a two-split photodetector 36 used to detect the movement to the traveling direction of an object lens 7 is installed. After the inclination of the object lens 7 has been adjusted, the direction of the dividing line LV is adjusted by using the adjusting mechanism 50 in such a way that the dividing line LV of the two-split photodetector 36 is made parallel to the optical-axis direction of a laser beam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to at least a portion including an objective lens moving mechanism for moving an objective lens for focusing a laser beam on a recording medium in a focusing direction and a tracking direction, at least the objective lens and the objective lens moving mechanism. The present invention relates to an optical pickup device which is connected to a moving housing that moves in the radial direction of the recording medium, and in which the adjusting mechanism is provided at the connecting portion so as to align the optical axis of the objective lens with the optical axis of the moving housing.

[0002]

2. Description of the Related Art In an optical disk drive apparatus, an optical pickup apparatus used for recording / reproducing data on / from an optical disk uses a laser beam as an optical disk so that its movable weight can be reduced and a high-speed seek operation can be performed. A so-called separation optical system is practically used in which an optical system around an objective lens which is focused on is separated from other optical systems and only the separated optical system is moved. An example of an optical pickup device of such a separation optical system is shown in FIG.

In FIG. 1, an optical disk 3 is removably attached to a turntable 2 fixed to a rotary shaft of a spindle motor 1.
The optical pickup device for recording / reproducing data on / from the recording surface is divided into a fixed optical system 4 and a moving optical system 5.
Further, the carriage 5 a of the moving optical system 5 is provided with a seek mechanism 6 for moving the moving optical system 5 in the radial direction of the optical disc 3.

On the carriage 5a of the moving optical system 5, an objective lens 7 for focusing the laser beam on the recording surface of the optical disc 3 and a deflection prism 8 for connecting the optical axis of the fixed optical system 4 to the objective lens 7 are provided. Is provided, and in addition,
The objective lens 7 is provided with an objective lens actuator 9 for driving the objective lens 7 in the focusing direction and the tracking direction, and the objective lens actuator 9 is fixed to the carriage 5a with screws.

The lower part of the objective lens actuator 9 is formed on a part of a spherical surface centered inside the objective lens 7, and the objective lens actuator 9 is attached to the carriage 5a with the objective lens 7 as the center. It can be adjusted to any angle.

An example of the objective lens actuator 9 is shown in FIG.
0 and FIG.

In the figure, a focusing coil 12 is wound around an objective lens holder 11 which holds the objective lens 7, and side surfaces 11a, 1 of the objective lens holder 11 are wound.
On the surface of the focusing coil 12 corresponding to 1b,
The tracking coils 13 and 14 and the tracking coils 15 and 16 each made of a planar coil are adhesively fixed.

The base member 17 includes a magnetic circuit member 21 including an outer yoke member 18, an inner yoke member 19, and a permanent magnet 20, an outer yoke member 22, an inner yoke member 23, and a permanent magnet 24. Magnetic circuit member 2
5 are provided, and the inner yoke member 19 and the inner yoke member 23 are inserted into the holes 11c and 11d formed in the objective lens holder 11, respectively.

As a result, the focusing coil 12 is inserted into the magnetic gap of the magnetic circuit member 21 and the magnetic gap of the magnetic circuit member 25, and the tracking coils 13 and 14 are inserted into the magnetic gap of the magnetic circuit member 21.
Is inserted, and the tracking coils 15 and 16 are inserted into the magnetic gap of the magnetic circuit member 25.

Further, one end of two sets of parallel leaf springs 26, 27, 28, 29 is fixed to the supporting portions 11e, 11f, 11g, 11h provided on the objective lens holder 11. The other ends of the parallel leaf springs 26, 27, 28, 29 are attached to a support member 30, which supports the base member 17 and the outer yoke member 18.
It is rotatably supported between the bearing members 31 fixed to.

As a result, the objective lens holder 11 is supported by the parallel leaf springs 26, 27, 28 and 29 so as to be movable with respect to the base member 17 in the focusing direction, and is also supported by the base member 17 in the tracking direction. It is rotatably supported. In addition, the base member 17
As described above, the lower part of is formed so as to form a part of a spherical surface centered on a point (principal point) inside the objective lens 7.

An aperture member 33 arranged in parallel with the tracking direction is attached to one side surface of the objective lens holder 11 where the tracking coil is not provided, and the aperture member 33 has a tip substantially in the center thereof. Has a hole 34 formed therein.

Further, a light emitting element 35 facing the aperture member 33 and having its optical axis set in a direction orthogonal to the tracking direction, and a two-divided light receiving element for receiving the detection light output from the light emitting element 35. 36 are provided. The light receiving surface of the two-divided light receiving element 36 is divided into two light receiving surfaces 36a and 36b by a dividing line VL. The light emitting element 35 and the light receiving element 36 are mounted by mounting members 37 and 38 to a mounting seat 17a that is provided so as to project from a side end portion of the base member 17.

As a result, of the detection light output from the light emitting element 35, the light that has passed through the hole 34 of the aperture member 33 is received by the light receiving surfaces 36a and 36b of the two-divided light receiving element 36. Further, in a state in which the objective lens holder 11 is located at the tracking neutral position, the light receiving surfaces 36a and 36b of the two-divided light receiving element 36 have equal spot areas of the detection light output from the light emitting element 35. The positions of the light emitting element 35, the aperture member 33, the hole 34, and the two-divided light receiving element 36 are defined.

With the above configuration, the focusing coil 12
When a drive current is applied to the objective lens holder 11, a current interlinking the magnetic fields of the magnetic circuit member 21 and the magnetic circuit member 25 acts, and a thrust in the focusing direction acts on the objective lens holder 11 according to the magnitude and direction of the drive current. , With this thrust,
The objective lens holder 11 moves in such a manner that the restoring force of the deformation of the parallel leaf springs 26, 27, 28, 29 with respect to the focusing direction is balanced, and as a result, the position of the objective lens 7 in the focusing direction is determined.

Further, the tracking coils 13, 14, 1
When a driving current is applied to the magnetic circuit members 5 and 16, a current that links to the magnetic field of the magnetic circuit member 21 flows in the tracking coils 13 and 14, and a current that links to the magnetic field of the magnetic circuit member 25 flows in the tracking coils 15 and 16. Therefore, the thrust in the tracking direction corresponding to the magnitude and direction of the driving current at that time acts on the objective lens holder, and as a result, the objective lens holder 11 rotates about the rotation center 31a of the support member 30, Thus, the position of the objective lens 7 in the tracking direction is determined.

Further, the objective lens holder 11 rotates,
When the objective lens 7 moves in the tracking direction, the aperture member 33 moves in conjunction with it and the hole 34 moves in the tracking direction. Here, since the light emitting element 35 and the light receiving element 36 are fixed to the base member 17,
The position of the spot formed on the light receiving surface of the two-divided light receiving element 36 by the detection light that has passed through the hole 34 moves in the moving direction of the aperture member 33.

Therefore, of the light receiving surfaces 36a and 36b of the two-divided light receiving element 36, the light receiving surfaces 36a and 36b located on the side where the spot of the detection light has moved have a larger area for receiving the spot of the detection light. , The light receiving surface 36a,
The level of the light reception signal of 36b increases.

That is, by forming the difference between the light receiving signals output from the two light receiving surfaces 36a and 36b of the two-divided light receiving element 36, the deviation of the optical axis of the objective lens 7 from the reference position can be detected. ..

Generally, when the objective lens 7 is moved in the tracking direction, the optical axis of the objective lens 7 deviates from the optical axis of the moving optical system 5, so that the laser beam does not vertically enter the recording surface of the optical disc 3. Therefore, the optical axis of the reflected light from the recording surface of the optical disc 3 deviates from the optical axis of the moving optical system 5, and an error such as an offset component is added to a detection signal such as a focusing error signal or a tracking error signal formed by the fixed optical system 4. Produce ingredients. When this error component becomes large, for example, there arises a problem that the tracking servo control for causing the laser beam to follow the track on the recording surface of the optical disc 3 is lost.

In order to eliminate such inconvenience, the difference between the light receiving signals output from the two light receiving surfaces 36a and 36b of the two-divided light receiving element 36, that is, the signal representing the amount of movement of the objective lens 7 is determined by the moving optical system. Feedback is given to the control system of the seek mechanism 6 that drives the system 5 to move the moving optical system 5 in a direction in which the optical axis shift of the objective lens 7 is eliminated.

Further, for example, as shown in FIG. 12A, when the objective lens 7 is tilted and attached to the objective lens holder 11, the spot of the laser beam formed on the recording surface of the optical disc 3 has a coma aberration or a coma aberration. Astigmatism is generated, which adversely affects the focusing servo control for matching the focus of the laser beam on the recording surface of the optical disc 3.

Therefore, conventionally, as shown in FIG. 2B, the inclination of the objective lens actuator 9 is adjusted so that the optical axis of the objective lens 7 coincides with the optical axis of the moving optical system 5. It was

[0024]

However, such a conventional device has the following disadvantages.

That is, when the objective lens actuator 9 is attached to the carriage 5a by adjusting the inclination of the objective lens actuator 9 so that the optical axis of the objective lens 7 coincides with the optical axis of the moving optical system 5, the objective lens The moving direction of the actuator 9 in the focusing direction is not parallel to the optical axis direction of the objective lens 7.

For this reason, when the laser beam coincides with the recording track of the optical disc 3 and the tracking servo control of the objective lens 7 is in the locked state,
As shown in FIG. 13, when the objective lens 7 is moved from the solid line state to the focusing direction and positioned in the broken line state, the optical axis of the objective lens 7 indicated by the broken line and the optical axis of the moving optical system 5 are Causes an optical axis shift ZD. At this time, the locked state of the tracking servo control is held.

On the other hand, since the two-divided light receiving element 36 is fixed to the base member 17 of the objective lens actuator 9, the direction of the dividing line LV is parallel to the focusing direction of the objective lens actuator 9.

Therefore, as described above, even if the optical axis shift ZD occurs due to the movement of the objective lens 7 in the focusing direction while the tracking servo control of the objective lens 7 is in the locked state, in this case Since the objective lens 7 has not moved in the tracking direction, the light receiving signals output from the two light receiving surfaces 36a and 36b of the two-divided light receiving element 36 have the same value, and the moving optical system 5 is moved by the seek mechanism 6. I don't know.

As a result, the optical axis shift ZD is not eliminated, and as described above, there is a problem that an error component is generated in the detection signal formed by the fixed optical system 4.

The present invention has been made in order to eliminate such inconvenience of the conventional apparatus, and an optical pickup apparatus capable of suppressing the occurrence of optical axis deviation when the objective lens is tilted and attached to the objective lens actuator. Is intended to provide.

[0031]

According to the present invention, at least a portion including an objective lens moving mechanism for moving an objective lens for focusing a laser beam on a recording medium in a focusing direction and a tracking direction, at least the objective lens and the objective lens moving mechanism. In the optical pickup device, the mechanism is connected to a moving housing that moves in the radial direction of the recording medium, and an adjusting mechanism for matching the optical axis of the objective lens and the optical axis of the moving housing is provided at the connecting portion. A light projecting unit that outputs detection light linked to the movement of the objective lens moving mechanism in the tracking direction, and a detection light spot of the light projecting unit when the objective lens moving mechanism is in the tracking neutral state A split light receiving element that receives light on a split line, and the direction of the split line of the split light receiving element is defined as the optical axis of the moving housing. It is provided with a dividing line adjusting means for supporting the movable housing in an adjustable direction, and a controlling means for moving the moving casing based on a difference between light receiving signals output from two light receiving surfaces of the two-divided light receiving element. ..

Further, at least a portion including the objective lens moving mechanism for moving the objective lens for focusing the laser beam on the recording medium in the focusing direction and the tracking direction, at least the objective lens and the objective lens moving mechanism in the radial direction of the recording medium. In the optical pickup device, which is connected to the moving housing that moves to, and at the connecting portion is provided an adjusting mechanism for aligning the optical axis of the objective lens with the optical axis of the moving housing, the tracking direction of the objective lens moving mechanism is A light-emitting element that outputs detection light in a direction orthogonal to each other, an aperture member that moves in conjunction with the movement of the objective lens moving mechanism in the tracking direction and narrows down the detection light output by the light-emitting element, and the light that the aperture member narrows down. When the objective lens moving mechanism is in the tracking neutral state, A split light receiving element that receives light on a split line of its light receiving surface, split line adjusting means that adjustably supports the direction of the split line of the split light receiving element in a direction parallel to the optical axis of the movable housing, and A control means is provided for moving the moving housing based on the difference between the light receiving signals output from the two light receiving surfaces of the two-divided light receiving element.

Further, at least a portion including the objective lens moving mechanism for moving the objective lens for focusing the laser beam on the recording medium in the focusing direction and the tracking direction, at least the objective lens and the objective lens moving mechanism in the radial direction of the recording medium. In the optical pickup device, which is connected to the moving housing that moves to, and at the connecting portion is provided an adjusting mechanism for aligning the optical axis of the objective lens with the optical axis of the moving housing, the tracking direction of the objective lens moving mechanism is An optical branching unit that guides a part of the laser beam to the outside of the objective lens moving mechanism in a direction orthogonal to the optical axis of the laser beam and a spot formed by the light branched by the optical branching unit is the objective. Light is received on the dividing line of the light receiving surface when the lens moving mechanism is in the tracking neutral state. From the two light receiving surfaces of the two-divided light-receiving element, the two-divided light-receiving element, and the division-line adjusting means that adjustably supports the direction of the division line of the two-divided light-receiving element in the direction parallel to the optical axis of the movable housing. It is provided with a control means for moving the moving housing based on the difference between the received light output signals.

[0034]

Therefore, the dividing line of the two-divided light receiving element for detecting the displacement of the objective lens in the tracking direction is parallel to the optical axis of the moving housing, and the objective lens is
Since the optical axis of the objective lens and the optical axis of the moving housing are guided and moved in the direction of the dividing line, the optical axis deviation is suppressed.

[0035]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an optical disk drive device according to an embodiment of the present invention. In addition, in FIG.
The same parts and corresponding parts are designated by the same reference numerals. The optical pickup device of this optical disk drive uses a push-pull method as a tracking error detection method and a knife edge method as a focusing error detection method.

In the figure, the signal light output from the semiconductor laser element 41 of the fixed optical system 4 is converted into parallel light by the coupling lens 42 and enters the polarization beam splitter 43 as P-polarized light. Signal light is
The quarter-wave plate 4 is transmitted through the polarization beam splitter 43.
Guided to 4.

The P-polarized signal light transmitted through the quarter-wave plate 44 is converted into circularly polarized light by the quarter-wave plate 44, reflected by the polarization prism 7 of the moving optical system 5, and then directed to the objective lens 7. It is guided, condensed by the objective lens 7, and focused on the recording surface of the optical disc 3.

The reflected light from the optical disc 3 is transmitted through the objective lens 7 to be converted into substantially parallel light, reflected by the polarizing prism 8 and returned to the fixed optical system 4, and the quarter wavelength plate 4 again.
It is incident on 4. As a result, the reflected light that has passed through the quarter-wave plate 44 is converted into linearly polarized light whose azimuth is orthogonal to the incident light, and is thereby reflected by the polarization beam splitter 43.

In this way, the polarization beam splitter 4
The reflected light from the optical disc 3 reflected by the optical disc 3 is focused by the lens 45, and about half of the light flux is reflected by the splitting mirror 46 forming the knife edge, and the tracking direction T (that is, the radial direction of the optical disc 3). )
The light is incident on a light receiving element 47 for detecting a tracking error, the light receiving surface of which is divided into two.

The remaining part of the light beam focused by the lens 45 is incident on a light receiving element 48 for detecting a focusing error, which has a light receiving surface divided into two parts by a dividing line parallel to the ridge line 46a of the dividing mirror 46. It

Then, a tracking error signal is obtained based on the difference between the light receiving signals output from the two light receiving surfaces of the light receiving element 47, and the light receiving output from the two light receiving surfaces of the light receiving element 48 is obtained. A focusing error signal is obtained based on the signal difference. Further, a reproduction signal from the optical disc 3 is formed based on the sum of the light receiving signal of the light receiving element 47 and the light receiving signal of the light receiving element 48.

Further, the objective lens 7 is provided with an objective lens actuator 4 for driving the objective lens 7 in the focusing direction and the tracking direction. Further, the lower portion 49a of the objective lens actuator 49 is formed on a part of a spherical surface having a center at a point (principal point) inside the objective lens 7, so that the objective lens actuator 49 can be attached to the carriage 5a. The objective lens 7 can be adjusted to an arbitrary angle around the center.

2 and 3 show an example of the objective lens actuator 49. In addition, in FIG.
0 and the same parts as those in FIG. 11 and corresponding parts are denoted by the same reference numerals.

In the figure, the two-divided light receiving element 36 is attached to the projecting portion 17a of the base member 17 via the attaching member 38 in the state where the adjusting mechanism 50 capable of adjusting the direction of the dividing line LV is provided. ing.

An example of this adjusting mechanism is shown in FIGS. 4 (a) and 4 (b).
Shown in.

In the figure, the back surface of the two-divided light receiving element 36 is adhered and fixed to a flat portion 52 provided at the tip of the holding member 51, and the axis of the holding member 51 is
It is rotatably supported by the mounting member 38. Further, the coil spring 53 inserted into the shaft of the holding member 51 is for generating a biasing force for restricting the rotation of the holding member 51 after the adjustment, and the E-ring 54.
Is for preventing the coil spring 53 from coming off the shaft of the holding member 51.

Since the objective lens 7 is tilted and fixed to the objective lens holder 11, the tilt of the objective lens actuator 49 is adjusted so that the optical axis of the objective lens 7 coincides with the optical axis of the moving optical system 5. When attached in this way, as shown in FIG. 5, the holding member 51 of the adjusting mechanism 50 is rotated to adjust the direction of the dividing line LV of the two-divided light receiving element 36 to be parallel to the optical axis.

For example, a microscope is provided near the focal point of the objective lens 7 on the optical axis of the laser beam, and the position of the focal point is detected by the microscope while checking the image of the microscope on the monitor. Then, in that state, the objective lens actuator 4
By moving both the objective lens 7 and the microscope up and down within the focus direction operation range of 9, the optical axis shift amount can be detected.

Then, the angle formed by the optical axis of the laser beam and the optical axis of the objective lens 7 can be calculated based on the focus movement amount and the optical axis shift amount, and the adjusting mechanism 50 is calculated according to the calculated angle. Is operated, the two-split light receiving element 36
The direction of the dividing line LV can be adjusted parallel to the direction of the optical axis of the laser beam.

FIG. 6 shows an example of the control system of the optical disk drive.

In the figure, the light receiving surface 47 of the light receiving element 47 is shown.
The light reception signal Pa output from a is added to the plus side input end of the subtractor 61 and one input end of the adder 62, and the light reception signal Pb output from the light receiving surface 47b of the light receiving element 47 is subtracted. Is added to the minus side input end of the device 61 and one input end of the adder 62.
The light receiving signal Pc output from the light receiving surface 48a of the light receiving element 48 is added to the plus side input end of the subtractor 63 and one input end of the adder 62, and the light receiving signal Pd output from the light receiving surface 48b of the light receiving element 48 is Is added to the minus side input terminal of the subtracter 63 and one input terminal of the adder 62.

The subtractor 61 subtracts the light receiving signal Pb from the light receiving signal Pa, and the result of the subtraction is the tracking servo control section 64 as a tracking error signal ET.
Has been added to. The subtractor 63 subtracts the light reception signal Pd from the light reception signal Pc, and the subtraction result is added to the focusing servo control unit 65 as a focusing error signal EF. The adder 62 calculates the total sum of the received light signals Pa, Pb, Pc, Pd,
The calculation result is added to the signal reproduction unit 66 as the reproduction signal RF.

The tracking servo control section 64 forms a tracking control signal ST for changing the tracking error to 0 based on the input tracking error signal ET. The tracking control signal ST is the tracking coil drive section 67. Has been added to. The tracking coil drive unit 67 supplies a drive current to the tracking coils 13 to 16 of the objective lens actuator 49 based on the input tracking control signal ST.

The focusing servo control section 65 changes the focusing error to 0 on the basis of the input focusing error signal ET.
The focusing control signal SF, which forms F, is applied to the focusing coil drive unit 68. The focusing coil drive unit 68 supplies a drive current to the focusing coil 12 of the objective lens actuator 49 based on the input focusing control signal SF.

The signal reproducing section 66 receives the input reproduction signal RF.
The data recorded on the optical disc 3 is reproduced on the basis of the above, and the reproduced data is added to the decoder 69. The decoder 69 detects and corrects the error contained in the reproduced data by using the error correction code added to the inputted reproduced data, and its output data is reproduced data as the control unit 70. Has been added to.

The encoder 71 adds a predetermined error correction code to the recording data output from the control unit 70, and the output data is added to the semiconductor laser drive control unit 72 as a recording signal. ..

The semiconductor laser drive controller 72 includes the controller 3
When the reproduction mode is set from No. 4, the semiconductor laser element 41 is driven to light at a predetermined reproduction level. When the recording mode is set by the control unit 70, the semiconductor laser element 41 is driven to light up in the recording mode based on the recording signal applied from the encoder 71. As a result, the output level of the semiconductor laser element 41 changes corresponding to the recording data, and the recording information corresponding to the recording data is recorded on the recording track of the optical disc 3.

The position detector 73 detects the position of the moving optical system 5 moved by the seek mechanism 6, and its detection signal is applied to the seek motor controller 74 as a position detection signal SP.

The light receiving signal Pe output from the light receiving surface 36a of the light receiving element 36 is added to the plus side input end of the subtractor 75, and the light receiving signal Pf output from the light receiving surface 36b of the light receiving element 36 is subtracted. It is added to the negative input terminal of the device 75. The subtractor 75 subtracts the light reception signal Pf from the light reception signal Pe, and the subtraction result is added to the seek motor control unit 74 as the optical axis shift signal EK.

The seek motor control section 74 drives the seek motor 76, which is the drive source of the seek mechanism 6, so that the value of the position detection signal SP becomes the value corresponding to the target position instructed by the control section 70. It is a thing. Further, when the optical axis deviation signal EK has a value other than 0, the seek motor control unit 74 drives the seek motor 76 in the direction in which the value becomes 0.

The light emitting element drive section 77 is for driving the light emitting element 35 to light when a control signal is applied by the control section 70.

The speed detector 78 detects the rotation speed of the spindle motor 1, and the detection signal thereof is applied to the spindle motor controller 79 as a speed detection signal SV.

The spindle motor control section 79 drives the spindle motor 1 so that the value of the speed detection signal SV becomes a value corresponding to the target speed instructed by the control section 70.

Further, the host interface circuit 80 is
This is for exchanging various data with a host device that uses this optical disk drive device as an external storage device.

With the above configuration, when the optical disk 3 is loaded in the optical disk drive, the spindle motor control section 79
Thereby, the spindle motor 1 is rotated at a predetermined rotation speed, which enables data recording / reproducing operations on the optical disc 3 by the optical pickup device.

Then, the moving optical system 5 is moved by the seek mechanism 6.
When the semiconductor laser element 41 is driven at the reproduction level in the state in which is moved to a predetermined initial position, the reflected light from the recording surface of the optical disc 3 is obtained, and the control unit 70 starts the operation of the focusing servo control unit 65. .. Accordingly, the focusing servo control operation is performed by the focusing servo control unit 65, and the focus position of the objective lens 7 is controlled so as to match the recording surface of the optical disc 3.

When the control of the focusing servo control unit 65 is locked, the control unit 70 starts the operation of the tracking servo control unit 64, whereby the tracking servo control operation by the tracking servo control unit 64 is performed. , The laser beam follows the recording track. At the same time, the control unit 70 controls the light emitting element 35.
Is driven to light. Therefore, thereafter, the light receiving signals Pe, P from the light receiving surfaces 36a, 36b of the two-divided light receiving element 36.
Since f is output, the optical axis shift signal EK is added to the seek motor control unit 74.

On the other hand, when the objective lens actuator 49 is driven in the tracking direction by the action of the tracking servo control section 65 and the objective lens 7 moves in the tracking direction, the position of the spot on the light receiving element 36 moves, which causes the optical axis. The value of the shift signal EK changes with the amount of movement.

Therefore, the value of the optical axis deviation signal EK applied to the seek motor control section 74 becomes a value corresponding to the value of the optical axis deviation accompanying the movement of the objective lens 7, and the seek motor control section 74 determines that optical axis deviation. The seek motor 80 is moved according to the value of the shift signal EK. As a result, the objective lens 7
The optical axis of is always controlled so as to coincide with the optical axis of the moving optical system 5.

At this time, for example, as shown in FIG. 7, since the objective lens 7 is tilted and fixed to the objective lens holder 11, the tilt of the objective lens actuator 49 is adjusted so that the optical axis of the objective lens 7 becomes When the movable optical system 5 is attached so as to coincide with the optical axis, the direction of the division line LV of the two-divided light receiving element 36 is adjusted so as to be parallel to the optical axis, as described above.

In this state, the tracking servo control unit 6
When the tracking servo control of No. 4 is in the locked state, when the objective lens 7 is moved from the state shown by the solid line in the drawing to the focusing direction and positioned in the state of the two-dot chain line, at this time, the above-mentioned conventional Similar to the example, the optical axis of the objective lens 7 and the optical axis of the moving optical system 5 are
Optical axis shift occurs.

On the other hand, at this time, the two-divided light receiving element 36
Since the spot SP of the detection light formed in 1 moves in the focusing movement direction as the objective lens 7 moves,
The light receiving surface 36b of the two-divided light receiving element 36 is
Since the area of the light spot is larger than that of a, the optical axis deviation signal EK applied to the seek motor control unit 74 has a positive polarity and a value corresponding to the deviation of the spot SP.

Therefore, the seek motor controller 74
The seek motor 76 is moved in the direction RA in which the value of the optical axis deviation signal EK becomes 0, whereby the objective lens 7 is
The optical axis of the objective lens 7 coincides with the optical axis of the moving optical system 5 by moving to the state shown by the broken line in the figure with respect to the reference optical axis.

That is, in this case, the two-divided light receiving element 36
The dividing line LV of extends in the direction parallel to the optical axis, and
The optical axis of the objective lens 7 coincides with the reference optical axis at the focus neutral position. Then, the operation of the seek motor 76 is controlled by the action of the seek motor control unit 74 so that the spot SP moves on the dividing line LV of the two-divided light receiving element 36. Therefore, as a result, the position of the objective lens 7 is controlled so that the optical axis does not deviate from the reference optical axis.

In this way, in this embodiment, since the optical axis of the objective lens 7 always coincides with the reference optical axis, an error component such as an offset component appears in the focusing error signal EF and the tracking error signal ET. Such a situation can be prevented.

FIG. 8 shows a part of an objective lens actuator according to another embodiment of the present invention.

In the figure, the objective lens 85 is provided at a position off the center of the cylindrical objective lens holder 86. A sliding shaft 89 is provided at the center of the objective lens holder 86 so as to project from the center of the base member 87. The sliding shaft 89 guides the focusing direction of the objective lens holder 86.

On the side surface of the objective lens holder 86,
A focusing coil 90 for moving the objective lens holder 86 in the focusing direction is wound around the portion excluding the central portion.

The lower surface 87a of the base member 87 is formed on a part of a spherical surface, and the spherical part contacts the upper end of the opening of the carriage 91. In addition, the base member 87 includes
The laser beam LB, which is parallel light, is used for the objective lens 85.
Is formed with a hole 87b for leading to.

Inside the objective lens holder 86,
A mirror 92 for extracting the laser beam LB at a portion which does not enter the objective lens 85 is provided in a direction orthogonal to the optical axis of the laser beam LB and orthogonal to the tracking direction. Laser beam LBa branched by this mirror 92
Is a hole 9 formed in the side surface of the objective lens holder 86.
After passing through 3, the light receiving surface of the two-divided light receiving element 94 is irradiated.

When the objective lens holder 86 is held at the neutral position in the tracking direction, the two-divided light receiving element 94 has a laser beam LBa on the dividing line of its light receiving surface.
Are attached to the base member 87 via the attachment member 95 in such a manner that the spots can be equally divided.

It should be noted that, in the figure, the illustration of the magnetic circuit member acting on the focusing coil 90 with a magnetic field and the element of the tracking movement mechanism for moving the objective lens holder 86 in the tracking direction are omitted.

In this embodiment, the objective is obtained by forming a difference between the light receiving signals output from the two light receiving surfaces of the two-divided light receiving element 94 and moving the seek system so that the value of the difference becomes zero. The optical axis shift when the lens 85 is moved in the tracking direction is eliminated.

As described above, in this embodiment, since a part of the laser beam LB used for recording / reproducing data is used as the detection light for irradiating the two-divided light receiving element 94, the detection light is output. Therefore, a light emitting element for driving the light emitting element, a driving circuit for the light emitting element, and the like are unnecessary, and the device cost can be reduced.

By the way, although the present invention is applied to the optical pickup device of the separation optical system in the above-described embodiments, the present invention is configured such that all the optical systems are housed in the same housing and the housing moves. The same can be applied to the above optical pickup device.

The focusing error detecting method and the tracking error detecting method of the optical pickup device are not limited to those described above.

[0088]

As described above, according to the present invention,
The dividing line of the two-divided light receiving element for detecting the displacement of the objective lens in the tracking direction is parallel to the optical axis of the moving housing, and the objective lens moves while being guided in the direction of this dividing line. Therefore, it is possible to obtain an effect that the optical axis shift between the optical axis of the objective lens and the optical axis of the moving housing is suppressed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an optical disk drive device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an objective lens actuator according to an embodiment of the present invention.

FIG. 3 is a plan view showing an objective lens actuator according to an embodiment of the present invention.

FIG. 4 is a perspective view and a sectional view showing an example of an adjusting mechanism.

FIG. 5 is a schematic diagram for explaining an adjustment work.

FIG. 6 is a block diagram showing a control system of an optical disk drive device according to an embodiment of the present invention.

FIG. 7 is a schematic diagram for explaining the operation of one embodiment of the present invention.

FIG. 8 is a partial schematic sectional view showing a main part of an objective lens actuator according to another embodiment of the present invention.

FIG. 9 is a schematic configuration diagram showing a conventional example of an optical disk drive.

FIG. 10 is a perspective view showing a conventional example of an objective lens actuator.

FIG. 11 is a plan view showing a conventional example of an objective lens actuator.

FIG. 12 is a schematic diagram for explaining tilt adjustment of an objective lens.

FIG. 13 is a schematic view for explaining the inconvenience of the conventional device.

[Explanation of symbols]

 36,94 Two-divided light receiving element 36a, 36b Light receiving surface 50 Adjustment mechanism 51 Holding member 52 Flat part 53 Coil spring 54 E ring 74 Seek motor control part 75 Subtractor 76 Seek motor

Claims (3)

[Claims] 1. A portion including an objective lens moving mechanism for moving an objective lens for focusing a laser beam on a recording medium in a focusing direction and a tracking direction, at least the objective lens and the objective lens moving mechanism being in a radial direction of the recording medium. In the optical pickup device, which is connected to the moving housing that moves to, and at the connecting portion, an adjusting mechanism for aligning the optical axis of the objective lens with the optical axis of the moving housing is provided, A light projecting means for outputting detection light linked to movement and a two-divided light receiving means for receiving the detection light spot of the light projecting means on the dividing line of its light receiving surface when the objective lens moving mechanism is in the tracking neutral state. Supports the element and the dividing line of the two-divided light receiving element so that it can be adjusted in the direction parallel to the optical axis of the moving housing. An optical pickup device comprising: a dividing line adjusting unit for controlling the moving housing and a control unit for moving the moving casing based on a difference between light receiving signals output from two light receiving surfaces of the two-divided light receiving element. 2. A portion including an objective lens moving mechanism for moving an objective lens for focusing a laser beam on a recording medium in a focusing direction and a tracking direction, at least the objective lens and the objective lens moving mechanism being in a radial direction of the recording medium. In the optical pickup device, which is connected to the moving housing that moves to, and at the connecting portion is provided an adjusting mechanism for aligning the optical axis of the objective lens with the optical axis of the moving housing, the tracking direction of the objective lens moving mechanism is A light emitting element that outputs detection light in a perpendicular direction, an aperture member that moves in conjunction with the movement of the objective lens moving mechanism in the tracking direction to narrow down the detection light output by the light emitting element, and the light that this aperture member narrows down. Of the spot of when the objective lens moving mechanism is in the tracking neutral state. A split light receiving element for receiving light on the split line of the light receiving surface, split line adjusting means for supporting the split line of the split light receiving element in a direction parallel to the optical axis of the movable housing, and An optical pickup device comprising a control means for moving the movable housing based on a difference between light receiving signals output from two light receiving surfaces of the divided light receiving element. 3. A portion including an objective lens moving mechanism for moving an objective lens for focusing a laser beam on a recording medium in a focusing direction and a tracking direction, at least the objective lens and the objective lens moving mechanism being in a radial direction of the recording medium. In the optical pickup device, which is connected to the moving housing that moves to, and at the connecting portion is provided an adjusting mechanism for aligning the optical axis of the objective lens with the optical axis of the moving housing, the tracking direction of the objective lens moving mechanism is An optical branching unit that guides a part of the laser beam to the outside of the objective lens moving mechanism in a direction orthogonal to the optical axis of the laser beam and a spot formed by the light branched by the optical branching unit is the objective. Divide into two to receive light on the dividing line of the light receiving surface when the lens moving mechanism is in the tracking neutral state. Output from the split light-receiving element, split-line adjusting means that adjustably supports the direction of the split line of the two-divided light-receiving element in a direction parallel to the optical axis of the movable housing, and two light-receiving surfaces of the two-divided light-receiving element. An optical pickup device comprising a control means for moving the movable housing based on a difference between received light receiving signals.