JPH0991744A - Optical pickup - Google Patents

Abstract

PROBLEM TO BE SOLVED: To electrically easily perform alignment adjustment and also to automate this alignment adjustment. SOLUTION: A laser unit 1 housing a laser diode is energized by springs 16-18 and is also pressed to be fitted via piezoelectric elements 13-15 to a fitting part of a pickup main body 8. Automation of the alignmental adjustment is feasible by adjusting voltages VR1-VR3 to be impressed upon electrodes of these piezoelectric elements 13-15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup used in an optical disk drive device or the like.

[0002]

2. Description of the Related Art Conventionally, an optical pickup used in a magneto-optical disk drive device is shown in FIGS.
The laser light emitted from the laser diode in the laser unit 1 passes through the collimator lens 2 to become parallel light and is incident on the compound prism 3. The laser light incident on the composite prism 3 is shaped into a beam by the shaping prism 3a, then passes through the polarization beam splitter 3b, and
The linearly polarized light is converted into circularly polarized light by the / 4 wavelength plate 3c and is emitted from the composite prism 3. The laser light emitted from the compound prism 3 is reflected upward by the rising mirror 4 and passes through the objective lens 5 to produce the magneto-optical disk 1.
1 is irradiated. Then, on the recording surface of the magneto-optical disk 11, this laser light is reflected by rotating the polarization plane in the direction according to the recording information due to the magneto-optical effect. Then, this reflected light returns to the compound prism 3 via the objective lens 5 and the raising mirror 4, and is converted into linearly polarized light whose polarization direction is orthogonal to that of the laser light by the quarter-wave plate 3c, whereby a polarized light beam is obtained. The light is reflected by the splitter 3b and is irradiated onto the light receiving portion of the magneto-optical signal detector 6 via the Wollaston prism 3d.

The magneto-optical signal detector 6 is configured such that the light receiving portion of a light receiving element such as a photodiode can be divided into, for example, four, and can be separately output, and the reflected light having different polarization plane inclinations is Wollaston. By receiving light at this light receiving portion via the prism 3d, the recorded information on the magneto-optical disk 11 can be reproduced from the output signal of each light receiving portion. Further, a focusing error signal and a tracking error signal can be obtained as servo signals from the output signal of the magneto-optical signal detector 6. The focusing error signal is a signal indicating whether or not the objective lens 5 for irradiating the magneto-optical disk 11 with the laser light is in focus, and by performing servo control for moving the objective lens 5 back and forth based on this signal. The focus of the laser light can always be focused on the magneto-optical disk 11.
The tracking error signal is a signal indicating whether or not the laser light is accurately irradiated onto the track of the magneto-optical disk 11, and servo control for displacing the objective lens 5 in the radial direction of the magneto-optical disk 11 based on this signal. By performing the above, the laser light can be made to follow the track of the magneto-optical disk 11. Also, the objective lens 5
When the track becomes unable to follow due to the displacement of, the pickup body 8 is moved along the guide rail 10.

Here, in order for the optical pickup to reproduce recorded information with high accuracy and to perform accurate servo control, the laser light must satisfy the following conditions.

(1) Laser light is irradiated perpendicularly to the recording surface of the magneto-optical disk 11.

(2) The laser light has sufficient parallelism.

(3) The optical axis of the laser light coincides with the optical axis of each optical component.

(4) Laser light is applied to the center of the light receiving portion of the magneto-optical signal detector 6.

For example, when the laser beam is irradiated onto the recording surface of the magneto-optical disk 11 while the condition (1) is not satisfied, the optical axis of the reflected light is tilted and the magneto-optical signal detector 6 is detected.
Since the light is received by the light receiving portion of the disc, the reproduction signal and the servo signal are inaccurate. Further, generally, if these conditions are not sufficiently satisfied, there is a possibility that the S / N ratio of the reproduction signal may be deteriorated or the servo control for focusing and tracking may become unstable.

Therefore, in the conventional optical pickup, the above conditions are satisfied by performing alignment adjustment for precisely adjusting the mounting position of each component in the assembly process.

[0011]

However, this alignment adjustment is performed by subtly displacing the three-dimensional position and angle of each component such as the laser unit 1 and the objective lens 5 by a screw or the like of the mounting portion. I have to adjust. Moreover, since the mounting position and angle of each of these parts interact with each other, these must be integrated and adjusted.

Therefore, in the conventional optical pickup, even a worker who is skilled in alignment adjustment in the assembling process is complicated and troublesome, so that the productivity in the assembling process is lowered and the manufacturing cost is increased. there were.

The present invention solves the above-mentioned conventional problems and provides an optical pickup in which alignment adjustment can be performed electrically easily by attaching a laser diode, a light receiving element or an optical component via a piezoelectric element. The purpose is to provide.

[0014]

In the optical pickup of the present invention, a laser diode is attached to an optical pickup main body through a transducer that generates a mechanical displacement according to an applied voltage, and an adjustable voltage is applied to the laser diode. Is provided with an alignment adjusting means, which achieves the above object.

Further, preferably, in the optical pickup of the present invention, a reproduction signal detecting photodetector is attached to the optical pickup main body through a transducer that generates a mechanical displacement according to an applied voltage, and an adjustable voltage is provided. Is provided to the transducer.

Further, preferably, in the optical pickup of the present invention, the objective lens is arranged so that the angle with respect to the optical axis is changed by the mechanical displacement of the transducer via the transducer which generates the mechanical displacement according to the applied voltage. Is attached to the optical pickup body, and alignment adjusting means for applying an adjustable voltage to the transducer is provided.

Further, preferably, in the optical pickup of the present invention, the collimator lens is attached to the optical pickup main body through a transducer that generates a mechanical displacement according to an applied voltage, and an adjustable voltage is applied to the transducer. An alignment adjusting means for applying is provided.

Further, preferably, the alignment adjusting means in the optical pickup of the present invention applies a voltage adjusted based on the output signal of the reproduction signal detecting photodetector or the servo signal detecting photodetector to the transducer. .

The operation will be described below.

With the above arrangement, when the alignment adjusting means applies a voltage to a transducer such as a piezoelectric element,
Mechanical displacement occurs in this transducer, and the mounting position or angle of the laser diode with respect to the optical pickup body changes. Therefore, by adjusting the voltage applied to the transducer by the alignment adjusting means, the mounting position or the angle of the laser diode can be appropriately changed, and the alignment can be electrically easily adjusted. Moreover, this is not limited to the laser diode, and is the same when the reproduction signal detecting light receiver, the objective lens, and the collimator lens are attached to the pickup body. In addition to directly attaching to the pickup main body via the piezoelectric element, these components include the case of indirectly attaching via a movable frame body for servo control such as an objective lens.

Further, when the mounting position or the angle of the laser diode or the like is deviated, the laser light is received at the deviated position of the light receiving portion of the reproduction signal detecting photodetector or the servo signal detecting photodetector. Accordingly, the alignment adjusting means detects the mounting position or the angle deviation of the laser diode or the like based on the output signals of the reproduction signal detecting photodetector or the servo signal detecting photodetector, and adjusts so as to correct this deviation. The applied voltage can be applied to the transducer. This makes it possible to automate the alignment adjustment.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

FIGS. 1 to 3 show a first embodiment of the present invention. FIG. 1 is an oblique side view showing a structure of a mounting portion of a laser unit to a pickup body, and FIG. 2 is an optical pickup portion. FIG. 3 is a cross-sectional plan view, and FIG. 3 is a vertical cross-sectional front view along the optical axis of the optical pickup. 13 to 1
The components having the same functions as those of the conventional example shown in FIG.

As shown in FIGS. 2 and 3, the optical pickup of this embodiment has a laser unit 1, a collimator lens 2 for guiding laser light emitted from a laser diode in the laser unit 1, and a compound prism. 3, a raising mirror 4 and an objective lens 5, and a magneto-optical signal detector 6 that receives the laser light, and these components are attached to a pickup body 8. Here, both the objective lens 5 and the raising mirror 4 are attached to the movable frame body 9. The movable frame 9 is attached to the pickup body 8, and the actuator (not shown) can be displaced in the focusing direction and the tracking direction to perform servo control of the focusing and tracking.
However, all other components are directly fixed to the mounting portion of the pickup body 8. The pickup body 8 itself is slidably mounted on the guide rail 10 so that it can move in the radial direction of the magneto-optical disk 11.

In the above optical pickup, the mounting position of the composite prism 3 on the pickup body 8 is used as a reference.
It is necessary to align the mounting positions and angles of the laser unit 1, the collimator lens 2, the magneto-optical signal detector 6, and the objective lens 5. And in this embodiment,
An optical pickup capable of electrically adjusting the alignment of the laser unit 1 will be described.

The laser unit 1, as shown in FIG.
The end surface on the negative side (left side in FIG. 1) in the C direction (left and right direction in FIG. 1) is brought into contact with the mounting portion of the pickup body 8 via the piezoelectric element 13, and in the D direction (up and down direction in FIG. 1). Both end faces on the negative side (lower side in FIG. 1) are piezoelectric elements 14 and 1, respectively.
It is adapted to come into contact with the mounting portion of the pickup body 8 via 5. In addition, this laser unit 1
The spring 16 biases the negative side in the C direction, and both ends are biased by the springs 17 and 18 to push the negative side in the D direction. Therefore, the laser unit 1 is mounted at a position displaced from the mounting portion of the pickup body 8 by the thickness of the piezoelectric elements 13 to 15.

The piezoelectric elements 13 to 15 are transducers for converting an electric signal (electric quantity) into a mechanical displacement (mechanical quantity). Electrodes are formed at both ends of a piezoelectric material such as piezoelectric ceramics, and a voltage applied to the electrodes. Mechanical displacement, that is, the thickness of the piezoelectric material is changed in accordance with the above. Voltages VR1, VR2, VR3 obtained by dividing the voltage of the power supply 19 by the variable resistors 20-22 are applied to the electrodes of the piezoelectric elements 13-15, respectively. Further, each of the piezoelectric elements 13 to 15 has a property that the thickness of the piezoelectric material becomes thinner as the voltages VR1, VR2, and VR3 become higher.

In the optical pickup having the above structure, when the variable resistor 20 is adjusted to change the voltage VR1, the piezoelectric element 1
Since the thickness of 3 changes, the laser unit 1 can be displaced in the C direction. For example, when the voltage VR1 is increased, the piezoelectric element 13 becomes thin, so that the laser unit 1
Is urged by the spring 16 and moves to the negative side in the C direction by a minute distance. In addition, the voltage V is adjusted by adjusting the variable resistors 21 and 22.
When R2 and VR3 are changed at the same time, the piezoelectric elements 14 and 15
Since the thickness of the laser changes similarly, the laser unit 1 can be displaced in the D direction. For example, the voltages VR2, V
When R3 is increased, the piezoelectric elements 14 and 15 become thinner, so that the laser unit 1 is biased by the springs 17 and 18
Translate a small distance to the negative side of the direction. Further, when the variable resistors 21 and 22 are adjusted to change the voltages VR2 and VR3 in opposite directions, the thicknesses of the piezoelectric elements 14 and 15 are changed in opposite directions, so that the C direction and the D direction of the laser unit 1 are changed. The angle of rotation about an axis perpendicular to can be changed. For example, when the voltage VR2 is increased and the voltage VR3 is decreased, the piezoelectric element 14 becomes thin and the piezoelectric element 15 becomes thick, so that the laser unit 1 rotates clockwise by a minute angle.

As a result, according to the optical pickup of the present embodiment, the laser unit 1 accommodating the laser diode can be moved in the C direction and the D direction only by adjusting the variable resistors 20 to 22.
Since it can be displaced in the direction or the angle can be changed, the operator does not need to manually perform the alignment adjustment using a screw or the like, and the workability of the alignment adjustment can be significantly improved.

4 to 5 show a second embodiment of the present invention. FIG. 4 is an oblique side view showing the structure of the mounting portion of the laser unit to the pickup body, and FIG. 5 is a laser beam beam. FIG. 6 is a front view showing the relationship between the inclination of γ and the light receiving surface of the magneto-optical signal detector. The first shown in FIGS. 1 to 3
Constituent members having functions similar to those of the embodiment are denoted by the same reference numerals, and description thereof is omitted.

In this embodiment, the same optical pickup as that of the first embodiment shown in FIGS. 2 to 3 will be described in which the alignment adjustment of the laser unit 1 is automated. The laser unit 1 containing the laser diode is
Similarly to the first embodiment shown in FIG. 1, the piezoelectric elements 13 to 1
It is abutted on the mounting portion of the pickup main body 8 via 5 and is biased by springs 16-18. However, as shown in FIG. 4, the voltage V output from the alignment adjustment circuit 23 is applied to the electrodes of the piezoelectric elements 13 to 15.
R1 to VR3 are applied via the buffer circuits 24 to 26. The alignment adjusting circuit 23 adjusts the voltage values of the voltages VR1 to VR3 based on the output signal of the magneto-optical signal detector 6 and outputs the adjusted voltage values. In the magneto-optical signal detector 6, the light receiving surface of the photodiode (PD) is divided into four regions W, X, Y and Z, and a light receiving signal according to the amount of received light is independently provided for each of the regions W to Z. W to Z can be output. Here, the shift in the C direction of the laser unit 1 corresponds to the shift in the left-right direction on the light receiving surface of the magneto-optical signal detector 6, and for example, when the position of the laser unit 1 shifts to the positive side in the C direction. Means that the beam of the laser light applied to the magneto-optical signal detector 6 mostly hits the regions W and Y on the left side of the light receiving surface, and when the laser unit 1 is deviated to the negative side in the C direction, It is assumed that most of the right side regions X and Z hit. The deviation of the laser unit 1 in the D direction corresponds to the deviation in the vertical direction on the light receiving surface of the magneto-optical signal detector 6. For example, when the position of the laser unit 1 is deviated to the positive side in the D direction. , A large amount of the laser beam hits the areas Y and Z on the lower side of the light receiving surface, and the laser unit 1
When it is shifted to the negative side of the direction, the area W on the upper side of the light receiving surface,
Many hits on the X side.

The alignment adjusting circuit 23 performs the calculation of (W + Y)-(X + Z) on the basis of the received light signals W to Z of the respective regions W to Z of the magneto-optical signal detector 6 so that C of the laser unit 1 is calculated. The deviation of the direction is detected, and the voltage VR1 applied to the piezoelectric element 13 is adjusted according to the calculation result. That is, for example, when the position of the laser unit 1 shifts to the positive side in the C direction and the beam of the laser light hits the regions W and Y in large numbers, the calculation result of (W + Y)-(X + Z) becomes a positive value. Therefore, the voltage VR1 is set to a higher voltage to thin the piezoelectric element 13, and the laser unit 1 is displaced to the negative side in the C direction, so that feedback is performed so that the calculation result becomes zero. Further, the alignment adjustment circuit 23 detects the deviation of the laser unit 1 in the D direction by performing the calculation of (Y + Z)-(W + X) based on the received light signals W to Z, and the voltage VR2 corresponding to the calculation result. , VR3 are applied to the piezoelectric elements 14 and 15. That is, for example, when the position of the laser unit 1 is shifted to the positive side in the D direction and a large amount of the laser beam hits the regions Y and Z, (Y + Z)-(W +
X) results in a positive value, the voltages VR2, VR3
Is set to a higher voltage to thin the piezoelectric elements 14 and 15, and the laser unit 1 is displaced to the negative side in the D direction to perform feedback so that the calculation result becomes zero. In the optical pickup having the above-described configuration, for example, in the assembly process, if the magneto-optical disk 11 is installed at a standard position and the laser diode of the laser unit 1 emits a laser beam, a magneto-optical signal detecting the laser beam is detected. The voltage VR1 to VR3 applied to each piezoelectric element 13 to 15 by the alignment adjusting circuit 23 is automatically adjusted based on the light receiving signals W to Z of the device 6, so that the laser unit 1 does not deviate in the C and D directions. VR1 to VR3 can be determined. Therefore, thereafter, if the voltages VR1 to VR3 determined by the alignment adjusting circuit 23 are constantly applied to the piezoelectric elements 13 to 15, the laser unit 1 can be arranged at an accurate position. The alignment adjustment of can be automated.

Incidentally, for example, by mounting a cylindrical lens or the like on the laser unit 1, the beam shape of the laser light emitted from the laser diode is set to an elliptical shape, and the light received in each region W to Z of the magneto-optical signal detector 6 is received. If (W + Z)-(X + Y) is calculated based on the signals W to Z, as shown in FIG. 5, if the elliptical beam shape has no inclination, the operation result is zero, but the inclination is to the right. In the case, the calculation result becomes a negative value, and when tilting to the left, the calculation result becomes a positive value. Therefore, the alignment adjustment circuit 23 causes (W + Z)-(X + Y) and (X + Y)-(W +
Z), the deviation of the angle of the laser unit 1 is detected, and the piezoelectric element 1 is detected according to the calculation results.
It is also possible to adjust the voltages VR2 and VR3 applied to 4, 15 to correct the angular deviation of the laser unit 1. That is, for example, when the angle of the laser unit 1 is shifted in the counterclockwise direction in FIG. 4, (W + Z)
Since the calculation result of − (X + Y) becomes a positive value, the voltage VR
2 to a higher voltage to make the piezoelectric element 14 thinner,
The voltage VR3 is set to a lower voltage to thicken the piezoelectric element 15,
The angle of the laser unit 1 can be displaced in the clockwise direction.

FIG. 6 shows a third embodiment of the present invention and is a front view showing the structure of the mounting portion of the magneto-optical signal detector to the pickup body. It should be noted that constituent members having the same functions as those of the first embodiment shown in FIGS. 1 to 3 are denoted by the same reference numerals and the description thereof will be omitted.

In this embodiment, the same optical pickup as that of the first embodiment shown in FIGS. 2 to 3 will be described in which alignment adjustment of the magneto-optical signal detector 6 is electrically performed. As shown in FIG. 6, the magneto-optical signal detector 6 has a G
The positive side (right side of FIG. 6) end face in the direction (right and left direction of FIG. 6) is brought into contact with the mounting portion of the pickup body 8 via the piezoelectric element 13, and the negative side of the H direction (up and down direction of FIG. 6) is abutted. The end surface on the side (lower side in FIG. 6) is brought into contact with the mounting portion of the pickup body 8 via the piezoelectric element 14. Further, the magneto-optical signal detector 6 is biased by the spring 16 and pressed toward the positive side in the G direction, and is also biased by the spring 17 and pressed toward the negative side in the H direction. Each piezoelectric element 1
Reference numerals 3 and 14 are the same as those used in the first embodiment, and the electrodes of these piezoelectric elements 13 and 14 are connected to the power source 1
The voltage VR obtained by dividing the voltage of 9 by the variable resistors 20 and 21.
1 and VR2 are applied respectively.

In the optical pickup having the above structure, when the variable resistor 20 is adjusted to change the voltage VR1, the piezoelectric element 1
Since the thickness of 3 changes, the magneto-optical signal detector 6 can be displaced in the G direction. Further, when the voltage VR2 is changed by adjusting the variable resistor 21, the thickness of the piezoelectric element 14 changes, so that the magneto-optical signal detector 6 can be displaced in the H direction.

As a result, according to the optical pickup of the present embodiment, the magneto-optical signal detector 6 can be displaced in the G direction and the H direction only by adjusting the variable resistors 20 and 21, so that the operator Since it is not necessary to manually perform alignment adjustment using a screw or the like, workability of this alignment adjustment can be significantly improved.

The piezoelectric element 14 is arranged on one end surface of the magneto-optical signal detector 6 on the negative side in the H direction, and another piezoelectric element 15 is arranged on the other end surface. If the voltages VR2 and VR3 are separately applied to the electrodes 15 and 15, the rotation angle of the magneto-optical signal detector 6 can be adjusted as in the laser unit 1 in the first embodiment.

FIG. 7 shows a fourth embodiment of the present invention and is a front view showing the structure of the mounting portion of the magneto-optical signal detector to the pickup body. The constituent members having the same functions as those in the third embodiment shown in FIG. 6 are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, the same optical pickup as that of the first embodiment shown in FIGS. 2 to 3 will be described in which the alignment adjustment of the magneto-optical signal detector 6 is automated. The magneto-optical signal detector 6 is brought into contact with the mounting portion of the pickup body 8 via the piezoelectric elements 13 and 14 as well as the springs 16 and 1 as in the third embodiment shown in FIG.
Energized by 7. However, as shown in FIG. 7, the voltages VR1 and VR2 output from the alignment adjustment circuit 23 are applied to the electrodes of the piezoelectric elements 13 and 14 through the buffer circuits 24 and 25, respectively.
The alignment adjusting circuit 23 adjusts the voltage values of the voltages VR1 and VR2 based on the output signal of the magneto-optical signal detector 6 and outputs the adjusted voltage values.

In the magneto-optical signal detector 6, the light receiving surface of the photodiode is divided into four areas W, X, Y and Z, and the light receiving signals corresponding to the light receiving amounts are independently provided for each of the areas W to Z. W to Z can be output.
Here, since the deviation of the magneto-optical signal detector 6 in the G direction corresponds to the deviation of the light receiving surface in the left-right direction, for example, when the position of the magneto-optical signal detector 6 deviates to the positive side in the G direction, When the beam of the laser light largely hits the regions W and Y on the left side of the light receiving surface and the magneto-optical signal detector 6 shifts to the negative side in the G direction, the beam of laser light mostly goes to the regions X and Z on the right side of the light receiving surface. Hit Also,
The deviation in the H direction of the magneto-optical signal detector 6 corresponds to the deviation in the vertical direction of the light receiving surface.
When the position of is shifted to the positive side in the H direction, the beam of laser light mostly hits the lower regions Y and Z of the light receiving surface, and the magneto-optical signal detector 6 is shifted to the negative side of the H direction. In this case, the areas W and X on the upper side of the light-receiving surface mostly hit.

The alignment adjustment circuit 23 detects the magneto-optical signal by performing the calculation of (X + Z)-(W + Y) based on the received light signals W-Z of the respective regions W-Z of the magneto-optical signal detector 6. The deviation of the container 6 in the G direction is detected, and the voltage VR1 applied to the piezoelectric element 13 is adjusted according to the calculation result. That is, for example, when the position of the magneto-optical signal detector 6 is shifted to the negative side in the G direction and the beam of the laser light hits the regions X and Z in large numbers, the calculation result of (X + Z)-(W + Y) is positive. Since the value becomes a value, the voltage VR1 is set to a higher voltage to thin the piezoelectric element 13 and the laser unit 1 is displaced to the positive side in the G direction, and feedback is performed so that the calculation result becomes zero. In addition, the alignment adjustment circuit 23
On the basis of the received light signals W to Z, (Y + Z)-(W +
The deviation of the magneto-optical signal detector 6 in the H direction is detected by performing the calculation of X), and the voltage VR2 corresponding to the calculation result is applied to the piezoelectric element 14. That is, for example, when the position of the magneto-optical signal detector 6 is shifted to the positive side in the H direction and the beam of the laser light hits the regions Y and Z in large numbers, (Y + Z)-(W
+ X) is a positive value, the voltage VR2 is set to a higher voltage to make the piezoelectric element 14 thinner, and the magneto-optical signal detector 6 is displaced to the negative side in the H direction. Give feedback to

In the optical pickup having the above structure, for example, in the assembly process, as shown in FIG. 3, the magneto-optical disk 11 is installed at a standard position so that the laser diode of the laser unit 1 emits laser light. , The alignment adjustment circuit 23 determines each piezoelectric element 13 based on the received light signals W to Z of the magneto-optical signal detector 6 that receives the laser light.
The voltages VR1 and VR2 applied to 14 can be automatically adjusted to determine the voltages VR1 and VR2 that eliminate the deviation of the magneto-optical signal detector 6 between the G direction and the H direction. Therefore,
After that, if the voltages VR1 and VR2 determined by the alignment adjusting circuit 23 are constantly applied to the piezoelectric elements 13 and 14, the magneto-optical signal detector 6 can be arranged at an accurate position. The alignment adjustment of the signal detector 6 can be automated.

The piezoelectric elements 14 and 15 are arranged on both end surfaces of the magneto-optical signal detector 6 on the negative side in the H direction, and are separately applied from the alignment adjusting circuit 23 to the electrodes of these piezoelectric elements 14 and 15. If the beam shape of the laser light emitted from the laser diode is made elliptical by attaching a cylindrical lens or the like to the laser unit 1 so as to output the voltages VR2 and VR3 of the magneto-optical signal detector 6, The adjustment of the rotation angle can also be automated.

FIG. 8 shows a fifth embodiment of the present invention and is a front view in vertical cross section showing the structure of the mounting portion of the objective lens to the movable frame. It should be noted that constituent members having the same functions as those of the first embodiment shown in FIGS. 1 to 3 are denoted by the same reference numerals and the description thereof will be omitted. This embodiment is shown in FIGS.
In the same optical pickup as the first embodiment shown in
What electrically performs the alignment adjustment of the objective lens 5 will be described. As shown in FIG. 8, the objective lens 5 is
One end is swingably attached to the movable frame body 9, and the other end side negative side in the E direction is brought into contact with the attachment portion of the movable frame body 9 via the piezoelectric element 13. Also, this objective lens 5
The other end side of the is constantly biased to the negative side in the E direction by being biased by the spring 16. The piezoelectric element 13 is the same as that used in the first embodiment, and a voltage V obtained by dividing the voltage of the power supply 19 by the variable resistor 20 is applied to the electrode of the piezoelectric element 13.
R1 is applied.

In the optical pickup having the above structure, when the voltage VR1 is changed by adjusting the variable resistor 20, the piezoelectric element 1
Since the thickness of 3 changes, the rotation angle of the objective lens 5 is changed to E
It can be displaced to the positive and negative sides of the direction. Therefore,
Since the angle of inclination of the objective lens 5 with respect to the optical axis can be changed to the positive or negative side in the E direction only by adjusting the variable resistor 20, it is necessary for the operator to manually perform alignment adjustment using a screw or the like. Is eliminated, and the workability of this alignment adjustment can be greatly improved.

FIG. 9 shows a sixth embodiment of the present invention, and is a front view in vertical section showing the structure of the attachment portion of the objective lens to the movable frame. It should be noted that constituent members having the same functions as those of the fifth embodiment shown in FIG.

In this embodiment, the same optical pickup as that of the first embodiment shown in FIGS. 2 to 3 will be described in which the alignment adjustment of the objective lens 5 is automated.
The objective lens 5 is similar to that of the fifth embodiment shown in FIG.
The other end is attached to the movable frame body 9 via the piezoelectric element 13 and the spring 16. However, as shown in FIG. 9, the voltage VR1 output from the alignment adjustment circuit 23 is applied to the electrodes of the piezoelectric element 13 via the buffer circuit 24. In addition, the alignment adjusting circuit 23, based on the output signal of the magneto-optical signal detector 6,
The voltage value of the voltage VR1 is adjusted and output.

In the magneto-optical signal detector 6, the light-receiving surface of the photodiode is divided into two regions X and Y, and the light-receiving signals X and Y corresponding to the amount of received light are independently provided for each of the regions X and Y.
Y can be output. Even if the magneto-optical signal detector 6 is divided into four areas W to Z, the two divided by (W + Y) in this case.
The light reception signal X in the case of division can be calculated, and the light reception signal Y in the case of two division can be calculated by (X + Z) in the case of four divisions. Here, since the inclination of the objective lens 5 in the E direction corresponds to the lateral shift of the light receiving surface of the magneto-optical signal detector 6, for example, the objective lens 5 has a rotation angle to the negative side (clockwise direction) in the E direction. When the objective lens 5 deviates to the positive side in the E direction, a large amount of the laser beam hits the area X side on the left side of the light receiving surface due to the aberration.
The area Y side on the right side of the light receiving surface mostly hits.

The alignment adjusting circuit 23 calculates Y-X based on the received light signals X and Y of the respective regions X and Y of the magneto-optical signal detector 6 to calculate the rotation angle of the objective lens 5 in the E direction. Deviation is detected, and the voltage VR1 applied to the piezoelectric element 13 is adjusted according to the calculation result. That is, for example, when the rotation angle of the objective lens 5 deviates to the negative side in the E direction and a large amount of the laser beam hits the area X side, Y−
Since the calculation result of X becomes a negative value, the calculation result becomes zero by lowering the voltage VR1 to thicken the piezoelectric element 13 and displacing the rotation angle of the objective lens 5 to the positive side in the E direction. Give feedback like:

In the optical pickup having the above-mentioned structure, for example, in the assembly process, as shown in FIG. 3, if the magneto-optical disk 11 is installed at the standard position and the laser light is emitted from the laser diode of the laser unit 1. , The alignment adjustment circuit 23 automatically adjusts the voltage VR1 applied to the piezoelectric element 13 based on the received light signals X and Y of the magneto-optical signal detector 6 that receives the laser light, and the E of the objective lens 5 is adjusted.
It is possible to determine the voltage VR1 at which there is no deviation in the rotation angle in the direction. Therefore, thereafter, if the voltage VR1 determined by the alignment adjustment circuit 23 is constantly applied to the piezoelectric element 13, the objective lens 5 can be arranged at an accurate angle, and the alignment adjustment of the objective lens 5 is automated. can do.

FIG. 10 shows a seventh embodiment of the present invention and is an oblique side view showing the structure of the mounting portion of the collimator lens to the pickup body. In addition, FIG.
Components having the same functions as those of the first embodiment shown in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted.

In this embodiment, the same optical pickup as that of the first embodiment shown in FIGS. 2 to 3 will be described in which the alignment of the collimator lens 2 is electrically adjusted. As shown in FIG. 10, the collimator lens 2 is
Upper and lower end surfaces on the positive side in the F direction are brought into contact with the mounting portion of the pickup body 8 via the piezoelectric elements 13 and 14. The upper and lower end surfaces of the collimator lens 2 on the negative side in the F direction are urged by springs 16 and 17 to be pressed toward the positive side in the F direction. The piezoelectric elements 13 and 14 are the same as those used in the first embodiment.
The voltage of the power supply 19 is applied to the electrodes of the variable resistors 20, 21
The voltages VR1 and VR2 divided by are applied.

In the optical pickup having the above-described structure, when the variable resistors 20 and 21 are adjusted to change the voltages VR1 and VR2 in the same manner, the thicknesses of the piezoelectric elements 13 and 14 are also changed, so that the F of the collimator lens 2 is changed. The position in the direction can be displaced to the positive or negative side. Therefore, the distance of the collimator lens 2 from the laser unit 1 can be changed only by adjusting the variable resistors 20 and 21, so that the operator does not need to manually perform the alignment adjustment by using a screw or the like. The workability of this alignment adjustment can be greatly improved.

11 and 12 show an eighth embodiment of the present invention. FIG. 11 is an oblique side view showing the structure of the mounting portion of the collimator lens to the pickup body, and FIG. 12 is the position of the collimator lens. FIG. 6 is a front view showing the relationship between the beam shape of laser light on the light receiving surface of the magneto-optical signal detector. The constituent members having the same functions as those of the seventh embodiment shown in FIG.

In this embodiment, the same optical pickup as that of the first embodiment shown in FIGS. 2 to 3 will be described in which the alignment adjustment of the collimator lens 2 is automated. The collimator lens 2 is attached to the attachment portion of the pickup body 8 via the piezoelectric elements 13 and 14 and the springs 16 and 17, as in the seventh embodiment shown in FIG. However, as shown in FIG. 11, the piezoelectric element 13,
The voltages VR1 and VR2 output from the alignment adjustment circuit 23 are applied to the electrode 14 through the buffer circuits 24 and 25. The alignment adjusting circuit 23 adjusts the voltage values of the voltages VR1 and VR2 based on the output signal of the magneto-optical signal detector 6 and outputs the adjusted voltage values.

In the magneto-optical signal detector 6, the light-receiving surface of the photodiode is divided into four regions W, X, Y and Z, and the light-receiving signal according to the amount of received light is independently provided for each of the regions W to Z. W to Z can be output.
Here, as shown in FIG. 12, when the collimator lens 2 is attached at an accurate distance with respect to the laser unit 1, the beam shape of the laser light becomes circular, but when the distance from the laser unit 1 increases ( If the beam shape of this laser light becomes an elliptical shape that is inclined to the right side when it shifts to the positive side in the F direction), and it tilts to the left side when it approaches the laser unit 1 (when it shifts to the negative side in the F direction). It becomes oval.

The alignment adjusting circuit 23 performs an operation of (W + Z)-(X + Y) on the basis of the received light signals W to Z of the respective regions W to Z of the magneto-optical signal detector 6 to perform F of the collimator lens 2. The deviation of the direction is detected, and the voltage VR1 to be applied to the piezoelectric elements 13 and 14 according to the calculation result,
Adjust VR2. That is, for example, when the collimator lens 2 is displaced to the positive side in the F direction and the beam shape of the laser light on the light receiving surface becomes an elliptical shape inclined to the right side, (W + Z)-(X +
Since the calculation result of Y) becomes a negative value, the voltages VR1 and VR2 are
Is set to a lower voltage to thicken the piezoelectric elements 13 and 14, and the collimator lens 2 is displaced to the negative side in the F direction to perform feedback so that the calculation result becomes zero.

In the optical pickup having the above-mentioned structure, for example, in the assembly process, as shown in FIG. 3, if the magneto-optical disk 11 is installed at a standard position and laser light is emitted from the laser diode of the laser unit 1. , The alignment adjustment circuit 23 determines the piezoelectric elements 13, 1 based on the received light signals W to Z of the magneto-optical signal detector 6 that receives the laser light.
The voltage V1 and VR2 applied to the lens 4 are automatically adjusted to eliminate the deviation of the position of the collimator lens 2 in the F direction from the voltage V.
R1 and VR2 can be determined. Therefore, after that,
The voltage VR1 determined by the alignment adjustment circuit 23,
By constantly applying VR2 to the piezoelectric elements 13 and 14, the collimator lens 2 can be arranged at a correct distance from the laser unit 1, and the alignment adjustment of the collimator lens 2 can be automated.

The alignment adjustments of the laser unit 1, the magneto-optical signal detector 6, the objective lens 5 and the collimator lens 2 shown in the above-described embodiment can be made by combining a plurality of them and electrically adjusting them. It can also be automated.

Further, in the above embodiment, the magneto-optical disk drive device has been described, but the present invention can be similarly applied to an optical pickup such as another optical disk drive device or an optical card drive device.

[0062]

As described above, according to the optical pickup of the present invention, alignment adjustment is performed by attaching a laser diode, an optical component or the like to the main body of the optical pickup via a transducer and adjusting the voltage applied to the transducer. Therefore, the workability of manual alignment adjustment in the assembly process can be significantly improved, or the alignment adjustment can be automated to improve productivity.

[Brief description of drawings]

FIG. 1 shows a first embodiment of the present invention and is an oblique side view showing a structure of an attachment portion of a laser unit to a pickup body.

FIG. 2 is a partial cross-sectional plan view of the optical pickup according to the first embodiment of the present invention.

FIG. 3 is a partial cross-sectional front view of the optical pickup according to the first embodiment of the present invention.

FIG. 4 shows a second embodiment of the present invention and is an oblique side view showing the structure of the mounting portion of the laser unit to the pickup body.

FIG. 5 shows a second embodiment of the present invention and is a front view showing the relationship between the beam inclination of the laser light and the light receiving surface of the magneto-optical signal detector.

FIG. 6 shows a third embodiment of the present invention and is a front view showing a structure of a mounting portion of the magneto-optical signal detector to the pickup body.

FIG. 7 shows a fourth embodiment of the present invention and is a front view showing a structure of a mounting portion of the magneto-optical signal detector to the pickup body.

FIG. 8 shows a fifth embodiment of the present invention and is a vertical cross-sectional front view showing the structure of the attachment portion of the objective lens to the movable frame body.

FIG. 9 shows a sixth embodiment of the present invention and is a vertical cross-sectional front view showing the structure of the attachment portion of the objective lens to the movable frame body.

FIG. 10 shows a seventh embodiment of the present invention,
It is an oblique side view which shows the structure of the attachment part to the pick-up main body of a collimator lens.

FIG. 11 shows an eighth embodiment of the present invention,
It is an oblique side view which shows the structure of the attachment part to the pick-up main body of a collimator lens.

FIG. 12 shows an eighth embodiment of the present invention,
It is a front view which shows the relationship between the position of a collimator lens and the beam shape of the laser beam in the light-receiving surface of a magneto-optical signal detector.

FIG. 13 is a partial cross-sectional plan view of an optical pickup, showing a conventional example.

FIG. 14 shows a conventional example and is a vertical cross-sectional front view taken along the optical axis of the optical pickup.

[Explanation of symbols]

 1 Laser Unit 2 Collimator Lens 5 Objective Lens 6 Magneto-Optical Signal Detector 8 Pickup Body 9 Movable Frame 13 Piezoelectric Element 14 Piezoelectric Element 15 Piezoelectric Element 19 Power Supply 20 Variable Resistor 21 Variable Resistor 22 Variable Resistor 23 Alignment Adjustment Circuit

Claims (5)

[Claims] 1. An optical device in which a laser diode is attached to an optical pickup main body via a transducer that generates a mechanical displacement according to an applied voltage, and alignment adjusting means for applying an adjustable voltage to the transducer is provided. pick up. 2. A reproduction signal detecting photodetector is attached to an optical pickup body via a transducer that generates a mechanical displacement according to an applied voltage, and an alignment adjusting means for applying an adjustable voltage to the transducer. An optical pickup provided. 3. An objective lens is attached to an optical pickup main body and adjusted so that an angle with respect to an optical axis is changed by a mechanical displacement of the transducer via a transducer that generates a mechanical displacement according to an applied voltage. An optical pickup provided with alignment adjusting means for applying a possible voltage to the transducer. 4. An optical device in which a collimator lens is attached to an optical pickup main body via a transducer that generates a mechanical displacement according to an applied voltage, and alignment adjusting means for applying an adjustable voltage to the transducer is provided. pick up. 5. The alignment adjusting means applies a voltage adjusted based on an output signal of the reproduction signal detecting photodetector or the servo signal detecting photodetector to the transducer. The optical pickup described in Crab.