JP2001307366A - Optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical pickup device which is capable of focusing and tracking adjustment in a short time with less energy consumption and which has a simplified driving mechanism. SOLUTION: The device is equipped with an objective lens 13 comprising a transparent piezoelectric element that is deformed by adding an electric field, and is designed to make the focal position of a laser beam adjustable by deforming the element by adding the electric field using a control circuit 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical pickup device, and more particularly to an optical pickup device for recording or reproducing information on an optical disk.

[0002]

2. Description of the Related Art In recent years, in many fields, the use of optical disks capable of recording a large amount of information at high density has been promoted. An optical disk is an optical information recording medium that has an excellent feature that information can be recorded or reproduced in a non-contact manner and a medium can be exchanged, and is particularly attracting attention as an optical disk file and an external storage medium of a computer.

[0003] Such an optical disc can record or reproduce information by an optical pickup using a semiconductor laser, for example, and can erase or rewrite the recorded information depending on the medium to be used.

FIG. 21 is a conceptual diagram showing a configuration of a conventional optical pickup device. The optical pickup device 500 includes:
An information recording / reproducing unit 502 and a driving unit 512 for driving the information recording / reproducing unit 502 are provided. The information recording / reproducing unit 502 includes a light source holder 503 that records or reproduces information on a disk-shaped recording medium 511 that rotates about a rotation axis 510, and a fine adjustment unit 504 for fine adjustment of the position of the light source holder 503. And Also, the light source holder 5
03 denotes a laser beam emitting / receiving unit 515, a reflecting mirror 505, an objective lens 506, and an objective lens holder 50.
7 and a position adjusting means 508 for the objective lens 506.

The information recording / reproducing means 502 includes a driving means 51
2, the information is moved in the radial direction of the recording medium 511, and information is recorded or reproduced in an arbitrary area of the recording medium 511. The laser light emitting / receiving means 515 is provided for the laser light 51.
9 and receives the laser beam 519 reflected from the recording medium 511. The reflection mirror 505 is a plane mirror that reflects the laser light 519. Objective lens 506
Is the laser beam 519 reflected by the reflection mirror 505
Is focused on the signal recording surface in the recording medium 511. The objective lens holder 507 holds the objective lens 506. The position adjusting means 508 of the objective lens 506 moves the objective lens holder 507 in a direction perpendicular to the information recording surface of the recording medium 511 to focus the laser beam 519 on the signal recording layer of the recording medium 511. .

In such an optical pickup device 500, except for an auxiliary laser beam for track servo, a single laser beam 519 is focused on a single recording track on a recording medium 511, and a single laser beam 519 is collected at a time. Read and write recording tracks. In this case, the recording medium 5 of the optical pickup device 500
Since the recording speed or the reproduction speed for the optical disk 11 depends on the rotation speed of the optical disk, it is necessary to rotate the recording medium 511 at a high speed in order to improve the recording speed or the reproduction speed. Therefore, it is required to prevent vibrations and increase the speed of signal processing.

FIG. 22 shows a conventional optical pickup device 50 capable of simultaneously reading and writing a plurality of recording tracks.
FIG. The same reference numerals as those in FIG. 21 denote the same components, and a description thereof will be omitted. The light source holder 503 further includes
A diffraction grating 509 and a diffraction grating adjusting unit 515 are provided. Diffraction grating 509 splits laser light 519 into substantially parallel laser light 514. Diffraction grating adjusting means 515 includes:
The diffraction grating 509 is finely adjusted so that the laser beam 519 is appropriately divided.

As described above, the optical pickup device 501 shown in FIG.
By dividing the laser beam 19 into a plurality of substantially parallel laser beams 514 and simultaneously reading and writing a plurality of recording tracks, high-speed reading and writing can be performed without increasing the rotation speed. Note that a birefringent substance may be used instead of the diffraction grating 509.

[0009]

In the conventional optical pickup devices 500 and 501 as described above, the optical disk 51
In order to focus on one information recording layer, it is necessary to control the focal length in the focus direction and the focus direction in the tracking direction by the objective lens adjustment unit 508 and the fine adjustment unit 504. In particular, DVD (digital versati
le disk) and CD (compact disk), the depth position of the information recording layer in the recording medium differs between DVDs and CDs due to differences in standards between DVDs and CDs. Such an objective lens adjusting means 508 was required to focus a laser beam on a different information recording layer. Therefore, control of the focal position of the laser beam requires mechanical driving by the objective lens adjusting unit 508 and the fine adjusting unit 504,
There is a problem that extra time and energy are required for the driving.

In order to focus the laser beam on both the information recording layers of the DVD and the CD, instead of providing such an objective lens adjusting means 508, each of the focal points is set as an objective lens. It is conceivable to use a bifocal lens that focuses the laser light. However, in this case, a signal from another focal point enters as noise and the signal quality is degraded.

In order to record or reproduce information in an arbitrary area of the information recording medium 511, the information recording / reproducing means 502 having a weight including the objective lens adjusting means 508 and the fine adjusting means 504 is driven by the driving means 512. It had to be driven. Therefore, there is a problem that extra time and energy are required for moving the information recording / reproducing means 502.

Furthermore, a conventional optical pickup device 501
In the case where a plurality of laser beams are generated, the focal distance of each laser beam is fixed by the physical arrangement of each component, or all laser beams 51
Only the focal distance of 4 could be changed at the same time.
Therefore, for example, in a three-beam optical pickup device, the focal position on the recording track can be adjusted up to two beams, but only the focal position of the third beam cannot be controlled alone. In some cases,
There is a problem that information cannot be read by the third beam, other than using a technology that can read even if the focus of the image sensor or the like is not on the recording track.

The present invention has been made in view of the above-mentioned problems, and realizes a high-speed driving of the information recording / reproducing means by the driving means and energy saving by reducing the weight of the information recording / reproducing means. By not controlling the focal position of the light by mechanical driving, high-speed control of the focal position and energy saving are realized.Furthermore, even when a plurality of laser beams are generated, the focal point is controlled for each laser beam. It is an object to provide an optical pickup device whose position can be adjusted.

[0014]

SUMMARY OF THE INVENTION An optical pickup device according to the present invention is an optical pickup device that irradiates a laser beam emitted from a light source to an information recording layer of a disk-shaped information recording medium. An objective lens for converging laser light emitted from the light source and irradiating the information recording layer, and applying a voltage to the objective lens to deform the shape thereof, Control means for controlling the focus position.

In the above optical pickup device,
The control means controls the focal position of the laser beam by applying an asymmetric voltage to the center of the objective lens and deforming the shape asymmetrically with respect to the objective lens. is there.

Further, in the optical pickup device,
A plurality of transparent electrodes are provided on the surface of the objective lens, and the control means applies a voltage to the objective lens via each of the transparent electrodes.

Further, an optical pickup device according to the present invention is an optical pickup device for irradiating a laser beam emitted from a light source to an information recording layer of a disk-shaped information recording medium, wherein the laser beam emitted from the light source is collected. Irradiating the information recording layer with an objective lens deformable by an external force, a piezoelectric element deformed by applying a voltage to apply a force to the objective lens, and applying a voltage to the piezoelectric element. And a control means for controlling the focal position of the laser beam by deforming the objective lens by applying force to the objective lens.

Further, in the optical pickup device,
The control means controls the focal position of the laser beam by applying a voltage to the piezoelectric element so that the objective lens is deformed asymmetrically with respect to the center.

Further, in the optical pickup device,
The control means controls a focal length of a laser beam in a focus direction.

In the above optical pickup device,
The control means controls a focus direction of a tracking direction of the laser light.

Further, in the optical pickup device,
The control means controls the focal length of the laser beam in the focus direction and the focus direction of the tracking direction at the same time.

In the above optical pickup device,
The control means, for a plurality of disc-shaped information recording media at different depth positions of the information recording layer, deforms the objective lens so that the laser beam is focused on each information recording layer, and The focus position of light is controlled.

In the above optical pickup device,
The plurality of disc-shaped information recording media are DVD and CD.
It is what it was.

Further, the optical pickup device according to the present invention reproduces a signal of an information recording layer of a disc-shaped information recording medium using a laser beam emitted from a light source, or reproduces a signal of the information recording layer. In the optical pickup device that performs the recording and, reflecting the laser light, a concave reflecting mirror as a deformable concave mirror, a single or a plurality of piezoelectric elements to deform the concave reflecting mirror,
A piezoelectric element control circuit for applying a voltage to the piezoelectric element to deform the concave reflecting mirror and controlling a focal position of laser light.

In the above optical pickup device,
The plurality of piezoelectric elements are arranged around the concave reflecting mirror.

The optical pickup device according to the present invention reproduces a signal of an information recording layer of a disc-shaped information recording medium using a laser beam emitted from a light source, or reproduces a signal of the information recording layer. In an optical pickup device that performs recording and recording, a piezoelectric element formed into a concave surface, and coated on the inner surface side of the piezoelectric element, reflect the laser beam, and a conductive coating having electrical conductivity, A concave reflecting mirror as a deformable concave mirror formed by a plurality of electrodes arranged on the outer surface side of the concave reflecting mirror, and applying a voltage between the conductive coating and the plurality of electrodes to the concave surface. A piezoelectric element control circuit for controlling the focal position of the laser beam by deforming the concave piezoelectric mirror by deforming the upper piezoelectric element. One in which the.

In the optical pickup device,
The piezoelectric element control circuit controls a focal length of a laser beam in a focus direction.

In the above optical pickup device,
The piezoelectric element control circuit controls a focus direction of a tracking direction of laser light.

Further, in the optical pickup device,
The piezoelectric element control circuit controls the focal length of the laser beam in the focus direction and the focus direction of the tracking direction at the same time.

In the above optical pickup device,
The piezoelectric element control circuit, for a plurality of disc-shaped information recording media at different depth positions of the information recording layer, by deforming the concave reflection mirror so that the laser beam is focused on each information recording layer The focus position of the laser light is controlled.

In the above optical pickup device,
The plurality of disc-shaped information recording media are DVD and CD.
It is what it was.

Further, in the optical pickup device,
The concave reflecting mirror is formed as a set of a plurality of concave portions, and is configured to generate a plurality of focal points of the laser light.

In the above optical pickup device,
A plurality of focal positions of laser light generated by the concave reflection mirror are controlled independently.

In the above optical pickup device,
A plurality of focal points of the laser beam generated by the concave reflection mirror are independently focused on a plurality of tracks of the disc-shaped information recording medium, so that a plurality of recording tracks are read simultaneously.

Further, in the optical pickup device,
When a single laser focus is required, only a single focus among a plurality of focuses of the laser light generated by the concave reflection mirror is focused on the disc-shaped information recording medium, and the other laser light focuses. Is prevented from being focused on the disc-shaped information recording medium.

In the above optical pickup device,
The concave reflecting mirror is symmetrical with respect to the center line or the center point of the concave reflecting mirror for the laser light directed to the focal point of the signal recording layer of the disk-shaped recording medium and the laser light reflected from the focal point. Alternatively, the light is reflected by a concave portion located at a point symmetric position.

In the above optical pickup device,
The laser light emitted from the light source and incident on the concave reflecting mirror is a laser light having a thickness close to the diameter of the concave reflecting mirror.

[0038]

(Embodiment 1) FIG. 1 is a view showing the structure of an optical pickup device according to Embodiment 1 of the present invention. A circuit 15 and a driving unit 12 are provided. The information recording / reproducing means 20 is composed of, for example, a transparent piezoelectric element such as quartz and has an objective lens 13 whose shape is changed by an applied electric field, and a voltage for applying a voltage thereto.
A plurality of transparent electrodes 16 provided on the surface of the objective lens 13
And the laser light 1 on the optical disc 3 via the objective lens 13.
And the laser beam emitting / receiving means 8 for receiving the return light from the optical disc 3 via the objective lens 13 and obtaining a reproduction signal from the received return light, and emitting the laser light from the laser light emitting / receiving means 8 And a reflecting mirror 7 that reflects the reflected light to enter the objective lens 13 and reflects the return light obtained through the objective lens 13 to enter the laser light emitting / receiving means 8. Instead of the laser light emitting / receiving means 8, another light source that emits laser light and a light receiving means that can receive return light may be separately provided. The transparent electrode 16 is connected to a control circuit 15 and a control signal line 14 provided outside the information recording / reproducing means 20 via an objective lens holder 21 having a contact point with the transparent electrode 16.
And the control circuit 15 is connected to the control signal line 14.
A voltage can be applied to the objective lens 13 by applying a voltage to the transparent electrode 16 through the interface, and an electric field applied to the objective lens 13 can be controlled by adjusting the voltage applied from the control circuit. it can. Thereby, the focal length of the objective lens 13 in the focus direction and the focal direction of the tracking direction are controlled. The focus direction refers to a direction perpendicular to the information recording surface of the recording medium 3, and the tracking direction refers to a radial direction of the recording medium 3, that is, a direction of a straight line connecting the center and the periphery of the recording medium 3. Say. The position of the objective lens 13 is fixed in the information recording / reproducing device 20. The optical disk 3 is disposed so as to face the objective lens 13 at a predetermined interval about the rotation axis 2. The information recording / reproducing means 20 can be moved in the track arrangement direction of the optical disc 3 by the driving means 12.

FIG. 5 is a schematic diagram showing the internal structure of the laser light emitting / receiving means 8. In FIG. 5, the laser light emitting / receiving means 8 includes a laser diode 50 for outputting laser light 1 having a predetermined wavelength, A laser beam diameter converter 51 for changing the diameter of the laser light 1 output from the diode 50 and outputting the same, and a photodetector 52 for receiving return light from the optical disk and converting it into an electric signal to extract a reproduction signal.
And The laser beam emitting / receiving means 8
As long as it can emit and receive laser light, another configuration may be used. For example, two or more laser diodes that output laser beams of different wavelengths may be provided, and these may be switched and used as needed.

Next, the operation of the optical pickup device according to the first embodiment will be described. Optical pickup device 27
Is moved by the driving means 12 in the radial direction of the recording medium 3, that is, in the direction of a straight line connecting the center and the periphery of the recording medium 3, and records or reproduces information in an arbitrary area of the recording medium 11. The laser light output from the laser light emitting / receiving means 8 is applied to a predetermined track of the information recording layer of the optical disk 3 via the mirror 7 and the objective lens 13.
The return light obtained from this information recording layer is
Then, a reproduction signal is obtained based on the return light which is incident on the laser light emitting / receiving means 8 via the mirror 7 and is received.

FIG. 3 is a plan view showing the structure of the objective lens 13. A plurality of transparent electrodes 16 are coated on the surface of the objective lens 13 so that each has a predetermined planar shape. , Not shown, are connected to the control signal line 14. The planar shape of the plurality of transparent electrodes 16 may be any shape as long as it is easy to adjust the electric field applied to the objective lens 13.

In this optical pickup device 27,
The objective lens 13 is formed of a transparent piezoelectric element, and has a plurality of transparent electrodes 16 on its surface as shown in FIG.
By changing the voltage applied to the transparent electrode 16, an electric field corresponding to the voltage is applied to the objective lens 13, and the shape of the objective lens 13 changes correspondingly, and the focal length, The position of the focal point can be changed by changing the focal point direction or the like.

For this reason, the optical disk 3 passes through the objective lens.
When the focus of the light irradiated on the information recording layer is adjusted on the information recording layer, the voltage applied to each of the plurality of transparent electrodes 16 from the control circuit 15 is adjusted, and the voltage applied to the objective lens 13 is adjusted. Voltage, for example, the objective lens 13
Is deformed so that its thickness changes. As a result,
The focal length changes, and focusing can be performed.

When it is necessary to finely adjust the tracking of the light irradiated on the information recording layer of the information recording medium via the objective lens, the voltage applied to the transparent electrode 16 is asymmetric with respect to the center of the objective lens 13. Is controlled so that the electric field applied to the objective lens 16 is asymmetric with respect to the center of the objective lens 13, and the objective lens 13 is asymmetrically deformed, so that the focal direction, that is, the center of the lens By changing the direction connecting the focal point, the focal point
Tracking can be adjusted so as to be accurately positioned on the track of the information recording layer.

For example, as shown in FIG.
By controlling the voltage applied to the objective lens 13 by adjusting the voltage applied to the transparent electrode 16 from above, the thickness of the objective lens is increased like 13a and the objective lens is asymmetric with respect to the center. Deformed and incident laser light
The focal position of the objective lens 13 obtained for 1 can be changed from the focal position 17 at the time of no deformation to the focal position 18.

As a result, the control circuit 15 sends the transparent electrode 16
By adjusting the voltage applied to the
, The focusing and tracking adjustment can be electrically controlled.

As described above, according to the optical pickup device according to the first embodiment, the control circuit 15 deforms the objective lens 13 made of a transparent piezoelectric element by applying a voltage. Focusing and tracking adjustment can be electrically controlled, and a focus drive mechanism that moves an objective lens for focusing, such as a conventional optical pickup device, which is a mechanical mechanism, and a track position There is no need for a track drive mechanism to move the optical pickup for fine adjustment,
The driving mechanism can be simplified, and the weight of the optical pickup can be reduced.

In addition, focusing and tracking can be performed instantaneously electrically, and there is no need to mechanically move a lens or the like as in the prior art, and the time for focusing and tracking can be reduced. Further, since only the objective lens 13 needs to be electrically deformed, it is possible to save energy as compared with a conventional device that drives a driving mechanism.

Although the first embodiment has been described using the optical disc 3 as the optical information recording medium, in the present invention, the optical pickup device can be used to store data on a disc-shaped optical information recording medium other than the optical disc. The same effects as those of the first embodiment can be obtained even when used for writing, reading, and the like.

(Embodiment 2) FIG. 4 shows Embodiment 2 of the present invention.
FIG. 2 is a view showing the structure of an optical pickup device according to the present invention, in which the same reference numerals as those in FIG. 1 denote the same or corresponding parts, and an optical pickup device 28 And a piezoelectric element 22 connected to the control signal line 14 around the objective lens 23.

In the optical pickup device 28 according to the second embodiment, by applying a voltage from the control circuit 15 to the piezoelectric element 22 through the control signal line 14, the shape of the piezoelectric element 22 changes. As a result, a force is applied from the piezoelectric element 22 to the objective lens 23, the objective lens 23 is deformed, and the focal length in the focus direction, the focal direction in the tracking direction, and the like are changed, so that the focal position can be changed. Has become.

Therefore, when the light irradiated on the information recording layer of the information recording medium via the objective lens 26 is focused on the information recording layer, the control circuit 15 sends the piezoelectric element 2
The voltage applied to the objective lens 2 is controlled by adjusting the voltage applied to the objective lens 2.
3 is deformed so that its thickness changes. As a result, the focal length changes, and focusing can be performed.

When it is necessary to finely adjust the tracking of the light irradiated onto the information recording layer of the information recording medium via the objective lens, the voltage applied to the piezoelectric element 22 is asymmetric with respect to the center of the objective lens 23. Is controlled so that the force applied from the piezoelectric element 22 to the objective lens 23 is asymmetric with respect to the center of the objective lens 23, and the objective lens 23 is asymmetrically deformed, so that the focal direction, that is, By changing the direction connecting the center of the lens and the focal point, tracking adjustment can be performed so that the focal point is accurately located on the track of the information recording layer of the optical disc 3.

As described above, according to the second embodiment, the focal position of the objective lens 23 is changed by adjusting the voltage applied from the control circuit 15 to the piezoelectric element 22.
Focusing and tracking adjustment can be electrically controlled.

In the second embodiment, the number, shape and arrangement of the piezoelectric elements 22 are different from those of the objective lens 23.
Any number, shape, and arrangement may be used as long as the arrangement can perform the deformation control with high accuracy. For example, the objective lens 23 is formed by four piezoelectric elements 22 in the shape of a lens holder.
May be sandwiched from all sides, and the piezoelectric element 22
If is transparent, a plurality of thin-film piezoelectric elements 22 may be attached to the surface of the objective lens 23.

(Embodiment 3) FIG. 6 is a schematic diagram showing a configuration of a main part of an optical pickup device according to Embodiment 3 of the present invention. In the optical pickup device shown in the first embodiment, when the optical disk 3 is a CD, the information recording layer 3a for a CD, and when the optical disk 3 is a DVD, the information recording layer 3b for a DVD, The control means 15 is used to change the shape of the objective lens 13 so that the focal point of the laser beam 1 is located. The objective lens 13a is deformed so that the focal point of the emitted light 1a is located on the CD information recording layer 3a.
3 is shown. The objective lens 13b shows the objective lens 13 deformed so that the focal point of the reflected light 1b is located on the DVD information recording layer 3b.

Next, the operation will be described. The operation other than the part related to the control of the objective lens 13 for adjusting the focal position of the laser light 1 is the same as that of the first embodiment, and the description is omitted here.

First, when the optical disk is a CD, the control circuit 15 changes the voltage applied to the objective lens 13 to deform the objective lens 13 like the objective lens 13a. Thus, the focal point of the laser beam 1a condensed by the objective lens 13a can be adjusted so as to be located on the information recording layer 3a for CD.

When the optical disk is a DVD, the control circuit 15 further changes the voltage applied to the objective lens 13 and deforms the objective lens 13 like the objective lens 13b. Thereby, the focal point of the laser beam 1b condensed by the objective lens 13a can be adjusted so as to be located on the information recording layer 3b for DVD.

The focal position of the objective lens 13 when there is no deformation may be set to one of the information recording layer 3a for CD and the information recording layer 3b for DVD.

As described above, according to the third embodiment, the control of the objective lens 13 by the control circuit 15 allows the focus of the laser beam to be adjusted, if necessary, to the information recording layer 3a for CD and the D.
It can be adjusted to the information recording layer 3b for VD, and does not require a bifocal objective lens or an objective lens driving mechanism for switching the information recording layer, so that the weight of the information recording / reproducing means can be reduced, and the information recording / reproducing can be performed. By reducing the weight of the means, the weight of the portion driven by the driving means 12 is reduced, and reduction in power consumption and high-speed operation performance can be realized.

(Embodiment 4) FIG. 7 is a schematic diagram showing a configuration of a main part of an optical pickup device according to Embodiment 4 of the present invention. In the optical pickup device shown in the second embodiment, when the optical disc 3 is a CD, the information recording layer 3a for a CD, and when the optical disc 3 is a DVD, the information recording layer 3b for a DVD, The piezoelectric element 22 is controlled by the control means 15 so that the focal point of the laser beam 1 is located, and the shape of the objective lens 23 is changed. The objective lens 23a has its outgoing light 1
The objective lens 23 is shown deformed so that the focal point a is located on the information recording layer 3a. Objective lens 23b
Shows the objective lens 23 deformed so that the focal point of the emitted light 1b is located on the information recording layer 3b.

Next, the operation will be described. The operation other than the part related to the control of the objective lens 23 for adjusting the focal position of the laser beam 1 is the same as that of the second embodiment, and the description is omitted here.

When the optical disk 3 is a CD, the control circuit 15 changes the voltage applied to the piezoelectric element 22 to deform the piezoelectric element 22. Due to the deformation of the piezoelectric element 22, a force is applied to the objective lens 23 to deform it like the objective lens 23a, so that the laser beam 1 is condensed by the objective lens 23a and the focal point is located on the information recording layer 3a for CD. become.

When the optical disk is a DVD, the control circuit 3 further changes the voltage applied to the piezoelectric element 22 and
The piezoelectric element 22 is deformed. Due to the deformation of the piezoelectric element 22, a force is applied to the objective lens 23 to deform it like the objective lens 23b, so that the laser beam 1 is condensed by the objective lens 23b and the focal point is located on the information recording layer 3b for DVD. become.

The focal position of the objective lens 23 when it is not deformed may be set at one of the information recording layer 3a for CD and the information recording layer 3b for DVD.

As described above, according to the fourth embodiment, the control of the piezoelectric element 22 by the control circuit 15 allows the laser beam to be focused on the CD information recording layer 3a and the DV
The information recording / reproducing means can be matched with the information recording layer 3b for D, so that a bifocal objective lens and an objective lens driving mechanism are not required, and the weight of the information recording / reproducing means can be reduced. The weight of the driving portion of the means 12 is reduced, and it is possible to reduce power consumption and achieve high-speed operation performance.

In the optical pickup device according to the third or fourth embodiment, the laser beam emitting / receiving means 8 is used.
As the laser beam 1, a plurality of laser diodes capable of outputting laser beams of different wavelengths may be used, and as the laser beam 1, laser beams of different wavelengths may be switched and used. In such a case, the same effects as those of the third and fourth embodiments can be obtained. For example, when the optical disc is a CD, laser light for a CD can be applied to the information recording layer corresponding to each optical disc, and when it is a DVD, laser light for a DVD can be applied to the information recording layer.

In the third and fourth embodiments, the optical pickup device which can be used for a CD and a DVD as an optical disk has been described. However, the present invention relates to a plurality of disks having different information recording layers having different depth positions. Can be applied to an optical pickup device using the same. In such a case, the same effects as those of the third or fourth embodiment can be obtained.

(Embodiment 5) FIG. 8 shows Embodiment 5 of the present invention.
FIG. 1 is a conceptual diagram showing a configuration of an optical pickup device according to the first embodiment.
The optical pickup device 150 includes the information recording / reproducing unit 101
, A driving unit 102, a piezoelectric element control circuit 103, and a control signal line 104. Information recording / reproducing means 101
Are a laser beam emitting / receiving means 105, a concave reflecting mirror 106, and a laser beam emitting / receiving means 105 for recording or reproducing information on a disk-shaped recording medium 111 which rotates around a rotation axis 110.
And piezoelectric elements 107 and 108. The internal configuration of the laser beam emitting / receiving unit 105 has the same configuration as that of the laser beam emitting / receiving unit described in the first embodiment with reference to FIG.

The concave reflecting mirror 106 emits laser light /
The laser light 109 from the light receiving means 105 is reflected to focus on the recording medium 111, and the laser light 109 reflected from the recording medium 111 is reflected and input to the laser light emitting / receiving means 105. It is a deformable concave mirror. Around the concave reflecting mirror 106, the piezoelectric element 10
7, 108 are arranged. Piezoelectric elements 107, 108
Changes its shape when a voltage is applied, and deforms the concave reflecting mirror 106. Piezoelectric element control circuit 10
3 designates piezoelectric elements 107, 10 via control signal line 104.
A voltage is applied to 8 and the voltage is changed to control the focal length of the concave reflecting mirror 106 in the focus direction and the focal direction in the tracking direction.

Next, the operation of the optical pickup device 150 according to the fifth embodiment will be described. Laser light emission /
The laser beam 109 emitted from the light receiving unit 105 is reflected by the concave reflecting mirror 106 and focuses on the recording medium 111. Then, the reflected light is reflected by the state of the recording track on the recording medium 111, and the reflected light is received again by the laser beam emitting / receiving means 105. In this way,
A signal on the recording medium 111 can be read. Similarly, information can be written to the recording medium 111.

Next, the operation of adjusting the focus of the laser beam 109 on the recording medium 111 when reading or writing data from the recording medium 111 will be described. The optical pickup device 150 according to the fifth embodiment does not include an objective lens, and the fine adjustment of the focal position of the laser beam 109 is performed by the piezoelectric element control circuit 103 using a voltage applied to the two piezoelectric elements 107 and 108. By changing the shape of the concave reflecting mirror 106.

FIG. 9 is a view for explaining deformation of the concave reflecting mirror 106 by the piezoelectric elements 107 and 108.
When the piezoelectric element control circuit 103 changes the focal position of the laser beam 109, the piezoelectric element control circuit 103 changes the voltage applied to the piezoelectric elements 107 and 108 to deform the piezoelectric elements 107 and 108. This piezoelectric element 107, 1
Due to the deformation 08, a force is applied to the concave reflecting mirror 106 to deform it, and the concave reflecting mirror 106 becomes a concave reflecting mirror 112. And
The focal point of the laser light 109 changes from the focal position 113 to the focal position 114. Therefore, the concave reflecting mirror 10
By controlling the shape of 6 by the piezoelectric element control circuit 103, the focal length of the reflected laser beam 109 in the focus direction and the focal direction of the tracking direction are electrically controlled, and the focal point of the laser beam 9 is set on the recording medium 111. Can be tied to.

As described above, according to the optical pickup device 150 of the fifth embodiment, the concave reflecting mirror 106 as a deformable concave mirror, and the piezoelectric element 107 that deforms the concave reflecting mirror 106 when a voltage is applied. ,
108, and a piezoelectric element control circuit 103 for controlling the deformation of the concave reflecting mirror 106 by applying a voltage to the piezoelectric elements 107, 108, so that the objective lens, the objective lens holder, the objective lens adjusting means, The laser beam 109 can be used without using the fine adjustment means for the tracking direction.
Is focused on the recording medium 111, and fine adjustment of the focus position in the focus direction and the tracking direction can be performed. Therefore, it is not necessary to provide the information recording / reproducing means 101 with an objective lens, an objective lens holder, an objective lens adjusting means, and a fine adjustment means for a tracking direction.
Since the piezoelectric element control circuit 103 can be provided outside the information recording / reproducing means 1, the weight of the information recording / reproducing means 101 can be reduced. Due to the weight reduction of the information recording / reproducing means 101, the weight of the portion driven by the driving means 102 is reduced, so that power consumption can be reduced and high-speed operation performance can be realized.

Also, since the fine adjustment of the focus position in the focus direction and the tracking direction is performed by applying a voltage to the piezoelectric elements 107 and 108 by the piezoelectric element control circuit 103, mechanical driving such as fine focus position adjustment means is performed. The number of mechanisms is reduced, and high-speed fine adjustment of the focus position and reduction of power consumption can be realized.

In the fifth embodiment, the piezoelectric elements 107 and 108 arranged around the concave reflecting mirror 106
Has been described as two, but this is merely an example. For example, the concave reflecting mirror 106 is formed by using two or more piezoelectric elements.
May be changed.

(Embodiment 6) FIG. 10 is a conceptual diagram showing a configuration of an optical pickup device according to Embodiment 6 of the present invention. The optical pickup device 160 includes the information recording / reproducing unit 1
01, driving means 102, piezoelectric element control circuit 103
And a control signal line 104. Information recording / reproducing means 1
01 further includes a laser beam emitting / receiving means 105 and a concave reflecting mirror 115. Note that the same reference numerals as those in FIG. 8 denote the same components, and a description thereof will be omitted.

FIG. 11 is a sectional view showing the structure of the concave reflecting mirror 115. As shown in FIG. The concave reflecting mirror 115 includes a concave piezoelectric element 116, a conductive coating 117 coated on the inner surface side of the concave piezoelectric element 116 to reflect the laser beam 109, and a plurality of concave elements disposed on the outer surface side of the concave piezoelectric element 116. It is a deformable concave mirror composed of electrodes 118a to 118h.

The concave piezoelectric element 116 is obtained by molding a piezoelectric element into a concave shape.
The shape changes. The conductive coating 117 is a coating having electrical conductivity and reflectivity sufficient to reflect laser light, and is coated on the inner surface side of the concave piezoelectric element 116. One example of the coating material is silver or the like.

FIG. 12 is a view showing the electrodes 118a to 118h arranged on the outer surface side of the concave reflecting mirror 115.
A voltage is independently applied between the conductive coating 117 and the electrodes 118a to 118h, and the potential between the conductive coating 117 and each of the electrodes 118a to 118h is changed. Changes. The piezoelectric element control circuit 103 controls the voltage applied between the conductive coating 117 and the electrodes 118a to 118h to finely control the focal length of the laser beam 109 in the focus direction and the focal direction in the tracking direction. I do.

Next, the operation of the optical pickup device 160 according to the sixth embodiment will be described. The concave reflecting mirror 1 for finely adjusting the focal position of the laser beam 109
The operation other than the part related to the control of No. 15 is the same as that of the fifth embodiment, and the description is omitted.

FIG. 13 is a diagram for explaining the deformation of the concave reflecting mirror 115 by the concave piezoelectric element 116. The piezoelectric element control circuit 103 changes the focal position of the laser beam 109 by independently changing the potential between the conductive coating 117 and the plurality of electrodes 118a to 118h and finely controlling the shape of the concave piezoelectric element 116. Let it. For example, when the piezoelectric element control circuit 103 applies a voltage between the conductive coating 117 of the concave reflecting mirror 115 shown in FIG. 13 and the plurality of electrodes 118a to 118h, the concave reflecting mirror 115 is indicated by a concave reflecting mirror 119. The laser light 109 is deformed into a shape
The focal position is changed from 0 to 121. Then, the focal length of the laser beam 109 in the focus direction and the focal direction in the tracking direction are finely adjusted electrically.

As described above, according to the optical pickup device 160 of the sixth embodiment, the concave reflecting mirror 115
With the concave piezoelectric element 116 and the conductive coating 117.
And the plurality of electrodes 118 a to 118 h, in addition to the same effect as in the fifth embodiment, since the concave reflecting mirror 115 itself is deformed, so that the focal length or the focal direction of the laser light 109 can be set to a wider range. Can be controlled. Therefore, even when the recording medium 111 is deformed, stable reading and recording of information can be performed.

(Embodiment 7) FIG. 14 is a conceptual diagram showing the configuration of an optical pickup device according to Embodiment 7 of the present invention. The optical pickup device 170 is provided with the information recording / reproducing means 1
01, driving means 102, piezoelectric element control circuit 103
And a control signal line 104. Information recording / reproducing means 1
01 further includes a laser beam emitting / receiving means 122 and a concave reflecting mirror 123. Note that the same reference numerals as those in FIG. 8 denote the same components, and a description thereof will be omitted.

The laser beam emitting / receiving means 122 generates a normal laser beam as a single thick laser beam 124 by a combination of concave and convex lenses, and receives the laser beam 124 reflected from the recording medium 111. As in the sixth embodiment, the concave reflecting mirror 123 includes a concave piezoelectric element (not shown), a conductive coating coated on the inner surface of the concave piezoelectric element to reflect the laser beam 124, and an outer surface of the concave piezoelectric element. And a plurality of electrodes arranged in the same.

FIG. 15 is a diagram showing electrodes arranged on the outer surface side of the concave reflecting mirror 123. In FIG. 15, for example, hatched portions indicated by 125a and 125b indicate electrodes. Similarly to the concave reflecting mirror 115 of the sixth embodiment, the concave reflecting mirror 123 of the seventh embodiment changes the shape of the concave reflecting mirror 123 by applying a voltage between the plurality of electrodes and the conductive coating. It is possible to control the focal position of the laser beam 124 by deforming. However, the concave reflecting mirror 12 according to the seventh embodiment
Numeral 3 is a multifocal mirror unlike the concave reflecting mirror 115 of the sixth embodiment. That is, as shown in FIG. 14, the concave reflecting mirror 123
It is divided into two laser beams 131a, 131b, 131c. Each laser beam 131a, 131b, 131c
By controlling the voltage applied to the piezoelectric element in each concave mirror portion of the concave reflecting mirror 123 corresponding to the above, fine adjustment of the focal position for each of the laser beams 131a, 131b, 131c is possible.

Next, the operation of the optical pickup device 170 according to the seventh embodiment will be described. The operation other than the part related to the control of the concave reflecting mirror 123 for finely adjusting the focal position of the laser light is described in the sixth embodiment.
Except that the laser light emitting / receiving means 105 is replaced with a laser light emitting / receiving means 122, the description is omitted.

First, a case where information is read from a recording track on the signal recording layer of the recording medium 111 will be described.
FIG. 16 shows a laser beam 124 by the concave reflecting mirror 123.
FIG. 6 is a diagram for explaining reflection of the light. The laser beam 124 emitted from the laser beam emitting / receiving means 122 is reflected by the concave reflecting mirror 123 to form three laser beams 131.
a, 131b, and 131c, and focuses on focal positions 126a, 126b, and 126c on the recording medium 111. Further, similarly to the sixth embodiment, by applying a voltage between the conductive coating and the plurality of electrodes, the concave piezoelectric element (not shown) is deformed, and the focal positions 126a,
26b and 126c can be moved independently. Therefore, the piezoelectric element control circuit 103 can control the three focal positions 126a, 126b, and 126c to be on the recording medium 111 at the same time. Then, information can be read from three recording tracks on the recording medium 111 at the same time.

Next, a case where information is written on the signal recording layer of the recording medium 111 will be described. FIG. 17 is a diagram for explaining the reflection of the laser beam 124 by the concave reflecting mirror 123 at the time of writing to the recording medium 111. When writing to the recording medium 111, the concave reflecting mirror 123
A plurality of laser beams 131a, 131b branched by
By focusing only the focal point of a single laser beam 131b on the recording medium 111 of the recording medium 111c, it is substantially the same as the case where writing to the recording medium 111 is performed by a single focal point concave mirror. For example, as shown in FIG. 17, only a single focal position 127b of the focal positions 127a, 127b, and 127c of the three laser beams 131a, 131b, and 131c is on the signal recording layer of the recording medium 111. In this case, the other focal positions 127a and 127c may not be located on the signal recording layer of the recording medium 111. The power control of the laser beam required for writing is as follows:
This is performed by controlling the output level of a laser source, for example, a laser diode.

As described above, the optical pickup device 170 according to the seventh embodiment includes the laser beam emitting / receiving means 122 capable of emitting a single thick laser beam 124 and the single thick laser beam 124 The provision of the concave reflecting mirror 123 which diverges into light and can focus the laser beam 124 on a plurality of recording tracks is provided. In addition to the same effects as in the second embodiment, recording is performed without using an image sensor or the like. The effect of reading data from a plurality of recording tracks on the medium 111 at the same time is obtained. Also,
Since a substantially single laser focus can be created, it can be used for writing on a writable recording medium such as a CD-R, for example. Further, by using a single thick laser beam as the laser beam 124, there is also an effect that the influence of the boundary between the focal points of the concave reflecting mirror 123 can be reduced. Further, when splitting a single thick laser beam 124 into a plurality of laser beams,
Since no diffraction grating or birefringent substance is used, the cost of the optical pickup device can be reduced. Note that the optical pickup device 170 can focus a large number of points in a narrow range.

FIG. 18 is a view for explaining the reflection of the laser beam 124 by the concave reflecting mirror 123. In the following description, the concave mirror portion is a concave reflecting mirror 123
Laser beam branched by the laser beam, for example, the laser beam 13
It refers to a part of the concave reflecting mirror 123 that reflects 1a.

Of the laser beam 124 emitted from the laser beam emitting / receiving means 122, the laser beam 129 reflected by the concave mirror portion above the concave reflecting mirror 123 is focused at a focal position 128 on the recording medium 111. Conclusion, the shape of the concave reflecting mirror 123 is changed so that it is reflected at the focal position 128 and is incident as a laser beam 130 on the concave mirror portion below the concave reflecting mirror 123, is reflected, and returns to the laser beam emitting / receiving means 122. It can also be controlled by the piezoelectric element control circuit 103. In this case, the laser light 130 traveling from the lower concave mirror portion of the concave reflecting mirror 123 to the focal position 128 is similarly reflected at the focal position 128 and becomes a laser beam 129 as the upper concave mirror portion of the concave reflecting mirror 123. Return to Also, the concave reflecting mirror 123
The laser beam 132 traveling from the concave mirror portion at the center to the focal position 128 is reflected at the focal position 128 and
The process returns to the central concave mirror portion of the concave reflecting mirror 123 as 32. Therefore, in this case, the multifocal concave reflecting mirror 123 makes the laser light heading toward the focal position 128 and the laser light reflected from the focal position 128 line-symmetric with respect to the center line of the concave reflecting mirror 123. The position will reflect.

The center line of the concave reflecting mirror 123 is a line passing through the center of the concave reflecting mirror 123 and parallel to the boundary between the concave mirror portions. In the above description,
For the sake of simplicity, the position of the focal point which is reflected by each of the upper, middle, and lower concave mirror portions of the concave reflecting mirror and forms the focal point on the recording medium 111 has been described as the focal position 128; Each laser beam 12
The focus positions of 9, 130, and 132 are different from one track of the recording track of the recording medium 111 by several tracks. That is, the focal position 128 shown in FIG.
Three focal points are shown in a very narrow area. As described above, by intersecting the laser light reflected from each concave surface near the focal position 128, it is possible to focus a large number of laser lights in a range much smaller than the distance between the concave mirror portions of the concave reflecting mirror 123. Can be.

In the seventh embodiment, the concave reflecting mirror 123 is shown as an example in which the mirror 123 is divided in the horizontal direction. However, the same applies to the division in the vertical direction or the combination of the horizontal and vertical directions and the vertical direction. I do. However, in the case of a multifocal concave reflecting mirror that combines the division in the horizontal direction and the vertical direction, the laser light from the laser light emitting / receiving means 122 and the laser light toward the laser light emitting / receiving means 122 are: Each is reflected at a point-symmetric position with respect to the center of the concave reflecting mirror. That is, for example, in the case of a concave reflecting mirror divided into three parts in the horizontal direction and the vertical direction, when the laser light from the laser light emitting / receiving means 122 is reflected by the lower right part of the concave reflecting mirror,
The light is reflected by the signal recording layer on the recording medium 111, returns to the upper left portion of the concave reflection mirror, is reflected, and returns to the laser light reflection / light receiving unit 122.

In the seventh embodiment, the case where the laser beam 124 by the concave reflecting mirror 123 is branched into three laser beams has been described. However, this is an example, and for example, the laser beam is branched into three or more laser beams. Alternatively, the laser beam may be split into two laser beams.

In the seventh embodiment, the recording medium 11
As the laser light used for writing to 1, the light reflected by the concave mirror portion at the center of the concave reflecting mirror 123 is used, but this is an example, and the laser light reflected by any concave mirror portion is used. It may be used at the time of writing.

In the seventh embodiment, the sixth embodiment is used.
Similarly, the concave reflecting mirror 123 is replaced with a concave piezoelectric element,
It consisted of a conductive coating and multiple electrodes,
Similar to the fifth embodiment, the concave reflecting mirror may have a configuration in which a plurality of piezoelectric elements are arranged around the concave reflecting mirror or at the boundary between the concave mirror portions of the concave reflecting mirror.

In the seventh embodiment, the laser beam 124 incident on the concave reflecting mirror 123 is a single thick laser beam. However, this is only an example.
If the concave reflecting mirror is composed of three concave mirror portions, one laser beam can be assigned to each concave mirror portion, that is, it can be realized using three laser beams.

(Eighth Embodiment) FIG. 19 is a schematic diagram showing a configuration of a main part of an optical pickup device according to an eighth embodiment of the present invention. In the optical pickup device shown in the fifth embodiment, when the recording medium 111 is a CD,
Information recording layer 111a and the recording medium 111
The piezoelectric element control means 103 controls the piezoelectric elements 107 and 108 so that the focal point of the laser beam 109 is located on the DVD information recording layer 111b in the case of VD, and changes the shape of the concave reflecting mirror 106. It is like that. The concave reflecting mirror 106a has the reflected light 1
The concave reflecting mirror 106 is shown in a deformed state such that the focal point 09a is located on the information recording layer 111a. The concave reflecting mirror 106b shows the concave reflecting mirror 106 deformed so that the focal point of the reflected light 109b is located on the information recording layer 111b.

Next, the operation will be described. The operation other than the part related to the control of the concave reflecting mirror 106 for adjusting the focal position of the laser beam 109 is the same as that of the fifth embodiment, and the description is omitted here.

When the recording medium 111 is a CD, the piezoelectric element control circuit 103 changes the voltage applied to the piezoelectric elements 107 and 108 to deform the piezoelectric elements 107 and 108. Due to the deformation of the piezoelectric elements 107 and 108, a force is applied to the concave reflecting mirror 106 to deform it like the concave reflecting mirror 106a, and the laser beam 109 is irradiated with the laser light 109.
The light is reflected by 6a, and the focal point is located on the information recording layer 111a for CD.

When the recording medium 111 is a DVD, the piezoelectric element control circuit 103 further changes the voltage applied to the piezoelectric elements 107 and 108 to deform the piezoelectric elements 107 and 108. Due to the deformation of the piezoelectric elements 107 and 108, a force is applied to the concave reflecting mirror 106 to deform it like the concave reflecting mirror 106b, and the laser light 109 is reflected by the concave reflecting mirror 106b and focuses on the information recording layer 111b for DVD. Will be located. Note that the focal position of the concave reflecting mirror 106 when there is no deformation may be set to one of the information recording layer 111a for CD and the information recording layer 111b for DVD.

As described above, according to the eighth embodiment, by controlling the piezoelectric elements 107 and 108 by the piezoelectric element control circuit 103, the focal point of the laser beam can be focused on the information recording layer 111a for CD and the DVD if necessary. The information recording layer 111b can be adjusted to the information recording layer 111b, and a bifocal objective lens and an objective lens driving mechanism are not required, so that the weight of the information recording / reproducing means 101 can be reduced. The weight of the part driven by the driving means 102 is reduced, so that a reduction in power consumption and high-speed operation performance can be realized.

(Embodiment 9) FIG. 20 is a schematic diagram showing a configuration of a main part of an optical pickup device according to Embodiment 9 of the present invention. In the optical pickup device described in the sixth embodiment, when the recording medium 111 is a CD,
Information recording layer 111a and the recording medium 111
In the case of VD, the information recording layer 111b for DVD
The shape of the concave reflecting mirror 115 is changed by the piezoelectric element control means 103 such that the focal point of the laser beam 109 is located. Concave reflection mirror 11
The reference numeral 5a indicates that the focal point of the reflected light 109a is the CD information recording layer 11
A concave reflecting mirror 115 deformed to be located at 1a is shown. The concave reflecting mirror 115b shows the concave reflecting mirror 115 deformed so that the focal point of the reflected light 109b is located on the DVD information recording layer 111b.

Next, the operation will be described. The concave reflecting mirror 115 for finely adjusting the focal position of the laser beam 109
The operations other than those related to the control are the same as those in the sixth embodiment, and the description is omitted here.

First, when the recording medium 111 is a CD,
The piezoelectric element control circuit 103 changes the voltage applied to the electrodes arranged on the outer surface side of the concave reflecting mirror 115 to deform the concave reflecting mirror 115 like a concave reflecting mirror 115a. Thereby, the focal point of the laser beam 109a reflected by the concave reflecting mirror 115a can be adjusted so as to be located on the information recording layer 111a for CD.

When the recording medium 111 is a DVD, the piezoelectric element control circuit 103 further changes the voltage applied to the electrodes arranged on the outer surface side of the concave reflecting mirror 115, and changes the concave reflecting mirror 115 to the concave reflecting mirror 115b. So that Thereby, the focal point of the laser beam 109b reflected by the concave reflecting mirror 115a can be adjusted so as to be located on the information recording layer 111b for DVD.

The focal position of the concave reflecting mirror 115 when there is no deformation may be set to one of the information recording layer 111a for CD and the information recording layer 111b for DVD.

As described above, according to the ninth embodiment, by controlling the concave reflecting mirror 115 by the piezoelectric element control circuit 103, the focal point of the laser beam can be adjusted as needed by the information recording layer 111a for CD and the DVD. Of the information recording / reproducing means 101, and the weight of the information recording / reproducing means 101 can be reduced by eliminating the need for a bifocal objective lens or an objective lens driving mechanism. The weight of the portion driven by the means 102 is reduced, so that a reduction in power consumption and high-speed operation performance can be realized.

In the optical pickup device according to the eighth or ninth embodiment, the laser light emitting / receiving means 8
As a laser light having a plurality of laser diodes capable of outputting a plurality of laser beams having different wavelengths, a laser beam having a plurality of different wavelengths may be used as the laser beam 109. In such a case, the same effects as those of the eighth and ninth embodiments can be obtained. For example, when the recording medium is a CD, it is possible to irradiate a laser beam for a CD to the information recording layer corresponding to each recording medium, and to irradiate a laser beam for a DVD when the DVD is a DVD.

In the eighth and ninth embodiments, an optical pickup device usable for a CD and a DVD as a recording medium has been described. However, the present invention relates to a plurality of recording media having different depth positions of information recording layers. In this case, the same effects as those of the eighth or ninth embodiment can be obtained.

In the fifth to ninth embodiments, the concave reflecting mirrors 106, 115, and 123 are substantially circular. However, this is merely an example. For example, a rectangular or elliptical concave reflecting mirror may be used. May be used.

Further, in the sixth, seventh and ninth embodiments, the arrangement of the plurality of electrodes on the concave reflecting mirrors 115 and 123 is made to be radial. May be arranged.

Further, the concave piezoelectric element according to the sixth, seventh and ninth embodiments may be a single piezoelectric element or a plurality of piezoelectric elements bonded in a mosaic pattern. You may.

[0116]

As described above, according to the present invention, in an optical pickup device for irradiating a laser beam emitted from a light source to an information recording layer of a disk-shaped information recording medium, a transparent piezoelectric element deformed by applying a voltage. Consisting of
An objective lens for condensing laser light emitted from the light source and irradiating the information recording layer with light, and control means for controlling a focal position of the laser light by applying a voltage to the objective lens to deform the shape thereof Since the laser beam focusing and tracking adjustment can be performed electrically, there is no need for a mechanical drive mechanism in the focus direction of the objective lens and a drive mechanism in the track direction of the optical pickup unit. In addition, the time required for laser beam focusing and tracking adjustment can be reduced, the weight of the device can be reduced, and the energy consumed can be reduced as compared with driving a mechanical drive device. As a result, it is possible to provide an optical pickup device with a simplified driving mechanism capable of realizing focusing and tracking adjustment in a short time and saving energy. Effect can be obtained.

Further, according to the present invention, in an optical pickup device for irradiating a laser beam emitted from a light source to an information recording layer of a disc-shaped information recording medium, the laser beam emitted from the light source is condensed to form the information beam. Irradiating the recording layer, an objective lens deformable by an external force, a piezoelectric element deformed by applying a voltage to apply a force to the objective lens, and applying a voltage to the piezoelectric element to shape the piezoelectric element By deforming, the objective lens is deformed by applying force, and control means for controlling the focal position of the laser light is provided, so that the focusing of the laser light and the tracking adjustment are performed electrically. This eliminates the need for a mechanical drive mechanism in the focus direction of the objective lens and a drive mechanism in the track direction of the optical pickup unit, and makes it possible to focus the laser beam. The time required for adjustment and tracking adjustment can be shortened, the weight of the device can be reduced, and energy consumption can be reduced as compared with driving a mechanical driving device. The effect is obtained that an optical pickup device with a simplified driving mechanism capable of realizing the adjustment in a short time with energy saving can be provided.

Further, according to the present invention, in the optical pickup device, the control means controls the laser recording on each information recording layer for a plurality of disc-shaped information recording media having different depth positions of the information recording layer. Since the objective lens is deformed so as to focus the light and the focus position of the laser light is controlled, it is necessary when the laser light is focused on the information recording surface of each information recording medium. In addition to eliminating the need for a mechanical objective lens drive mechanism and a bifocal lens, the time required for laser beam focusing and tracking adjustment can be reduced, the device can be made lighter, and a mechanical drive device can be used. Consumes less energy than driving the
The effect of providing an optical pickup device with a simplified driving mechanism capable of realizing focusing and tracking adjustment in a short time with energy saving can be obtained.

Further, according to the present invention, a concave reflecting mirror as a deformable concave mirror for reflecting a laser beam, one or more piezoelectric elements for deforming the concave reflecting mirror, and a voltage applied to the piezoelectric element. And a piezoelectric element control circuit for controlling the focal position of the laser beam by applying a voltage to deform the concave reflecting mirror to apply the objective lens, the objective lens holder, the objective lens adjustment means, and the fine adjustment means for the tracking direction. The focus of the laser beam can be focused on the recording medium without using it, and the focus positions in the focus direction and the tracking direction can be finely adjusted. Accordingly, it is not necessary to provide the information recording / reproducing means with an objective lens, an objective lens holder, an objective lens adjusting means, and a fine adjustment means for a tracking direction, and the piezoelectric element control circuit can be provided outside the information recording / reproducing means. Therefore, the weight of the information recording / reproducing means can be reduced. Due to this reduction in weight, the weight of the portion driven by the driving means is reduced, and power consumption can be reduced and high-speed operation performance can be realized.

Further, since the fine adjustment of the focus position in the focus direction and the tracking direction can be performed by applying a voltage to the piezoelectric element by the piezoelectric element control circuit, the number of mechanical drive mechanisms such as fine focus position adjustment means is reduced. In addition, high-speed fine adjustment of the focus position and reduction of power consumption can be realized.

Further, according to the present invention, a piezoelectric element formed into a concave shape, and a conductive coating, which is coated on the inner surface side of the piezoelectric element and reflects the laser light and has electrical conductivity, A concave reflecting mirror as a deformable concave mirror, formed by a plurality of electrodes arranged on the outer surface side of the concave reflecting mirror, and applying a voltage between the conductive coating and the plurality of electrodes, And a piezoelectric element control circuit for controlling the focal position of the laser beam by deforming the concave reflecting mirror by deforming the piezoelectric element on the concave surface. Means for focusing the laser beam on the recording medium without using any means and fine-tuning means for the tracking direction. It is possible to fine adjustment of the location. Accordingly, it is not necessary to provide the information recording / reproducing means with an objective lens, an objective lens holder, an objective lens adjusting means, and a fine adjustment means for a tracking direction, and the piezoelectric element control circuit can be provided outside the information recording / reproducing means. Therefore, the weight of the information recording / reproducing means can be reduced. Due to this reduction in weight, the weight of the portion driven by the driving means is reduced, and power consumption can be reduced and high-speed operation performance can be realized.

Further, since the fine adjustment of the focus position in the focus direction and the tracking direction can be performed by applying a voltage to the piezoelectric element by the piezoelectric element control circuit, a mechanical driving mechanism such as a fine position adjustment means for the focus position is reduced. In addition, high-speed fine adjustment of the focus position and reduction of power consumption can be realized.

Further, by deforming the concave reflecting mirror itself, there is an effect that the focal position can be controlled in a wide range.

Further, according to the present invention, in the optical pickup device, the piezoelectric element control circuit is provided for each of the plurality of disc-shaped information recording media having different information recording layer depth positions. Since the focus position of the laser light is controlled by deforming the concave reflection mirror so that the laser light is in focus, it is necessary to focus the laser light on the information recording surface of each information recording medium. By eliminating the need for a mechanical mechanism, the weight of the information recording / reproducing means can be reduced, the weight of the portion driven by the driving means can be reduced, and power consumption can be reduced and high-speed operation performance can be realized.

Further, according to the present invention, in the optical pickup device, the concave reflecting mirror is configured to generate a plurality of focal points of the laser beam, so that a plurality of focal points of the laser beam can be used without using an image sensor or the like. The effect is obtained that data can be read simultaneously from the recording tracks. In addition, since a substantially single laser focus can be created, it can be used for writing on a writable recording medium such as a CD-R, for example. When a single thick laser beam is used as the laser beam, there is also an effect that the influence of the boundary between the focal points of the concave reflecting mirror can be reduced.

Further, according to the present invention, a plurality of focal points of the laser beam generated by the concave reflecting mirror are independently focused on a plurality of tracks of the disk-shaped information recording medium, so that a plurality of recording tracks can be simultaneously recorded. Can be read,
There is an effect that data can be read simultaneously from a plurality of tracks on the recording medium 111 without using an image sensor or the like.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure of an optical pickup device according to Embodiment 1 of the present invention.

FIG. 2 is a diagram for explaining an operation of the optical pickup device according to the first embodiment of the present invention.

FIG. 3 is a plan view for explaining a structure of an objective lens of the optical pickup device according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a structure of an optical pickup device according to Embodiment 2 of the present invention.

FIG. 5 is a diagram illustrating a structure of a laser beam emitting / receiving unit of the optical pickup device according to the first embodiment of the present invention.

FIG. 6 is a diagram illustrating an optical pickup device according to a third embodiment of the present invention.

FIG. 7 is a diagram for explaining an optical pickup device according to a fourth embodiment of the present invention.

FIG. 8 is a conceptual diagram showing an optical pickup device according to Embodiment 5 of the present invention.

FIG. 9 is a diagram for explaining a change in a focal position according to a fifth embodiment of the present invention.

FIG. 10 is a conceptual diagram showing an optical pickup device according to Embodiment 6 of the present invention.

FIG. 11 is a diagram showing a configuration of a concave reflecting mirror according to Embodiment 6 of the present invention.

FIG. 12 is a diagram showing an outer surface side of a concave reflecting mirror according to a sixth embodiment of the present invention.

FIG. 13 is a diagram for explaining a change in a focal position according to a sixth embodiment of the present invention.

FIG. 14 is a conceptual diagram showing an optical pickup device according to Embodiment 7 of the present invention.

FIG. 15 is a diagram illustrating an outer surface side of a concave reflecting mirror according to a seventh embodiment of the present invention.

FIG. 16 is a diagram for explaining a focal position according to a seventh embodiment of the present invention.

FIG. 17 is a diagram for explaining a focal position according to the seventh embodiment of the present invention.

FIG. 18 is a diagram showing reflected light beams crossed by a concave reflecting mirror according to a seventh embodiment of the present invention.

FIG. 19 is a conceptual diagram showing a configuration of an optical pickup device according to Embodiment 8 of the present invention.

FIG. 20 is a conceptual diagram showing a configuration of an optical pickup device according to Embodiment 9 of the present invention.

FIG. 21 is a conceptual diagram showing a configuration of a conventional optical pickup device.

FIG. 22 is a conceptual diagram showing the configuration of another conventional optical pickup device.

[Explanation of symbols]

1, 109, 124 Laser light 2, 110 Rotation axis 3, 23 Optical disk 13, 23 Objective lens 7 Reflecting mirror 8, 105, 122 Laser light emitting / receiving means 12, 102 Driving means 13a, 13b, 23a, 23b Objective lens 14, 104 Control signal line 15 Control circuit 16 Transparent electrode 17 Focal position when not deformed 18 Focal position when deformed 20, 26, 101 Information recording / reproducing device 21 Object lens holder with contact with transparent electrode 22, 107, Reference Signs List 108 piezoelectric element 27, 28, 150, 160, 170 optical pickup device 103 piezoelectric element control circuit 106, 115, 123 concave reflection mirror 110 rotation axis 111 recording medium 111a, 111b information recording layer 116 concave piezoelectric element 117 conductive reflective coating 118a ~ 118h, 125a, 1 5b electrode

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 13/00 G02B 17/06 5D119 17/06 G11B 7/09 B G11B 7/09 C D G02B 7/18 BF term (reference) 2H042 DB14 DD04 DD05 DD13 DE07 2H043 BB05 BC00 2H044 DA01 DB04 DC01 2H087 KA13 LA01 NA00 PA01 PA17 PB01 RA27 RA45 TA01 TA03 TA05 5D118 AA04 AA26 BA01 BF02 BF03 CD02 CD03 CD08 A12 ABA11A12 DA05 EA02 EA03 EC44 EC45 FA05 JA44 JA48 JA53

Claims (24)

[Claims] 1. An optical pickup device for irradiating a laser beam emitted from a light source to an information recording layer of a disc-shaped information recording medium, wherein the optical pickup device is constituted by a transparent piezoelectric element which is deformed by applying a voltage and emitted from the light source. An objective lens for condensing laser light and irradiating the information recording layer, and control means for applying a voltage to the objective lens to deform the shape and control a focal position of the laser light. An optical pickup device characterized by the following. 2. The optical pickup device according to claim 1, wherein the control unit applies a voltage to the objective lens asymmetrically with respect to a center of the objective lens to deform the shape asymmetrically. An optical pickup device for controlling a focal position of the laser light. 3. The optical pickup device according to claim 1, wherein a plurality of transparent electrodes are provided on a surface of said objective lens, and said control means controls said transparent electrodes with respect to said objective lens. An optical pickup device characterized in that a voltage is applied through the optical pickup. 4. An optical pickup device for irradiating a laser beam emitted from a light source to an information recording layer of a disc-shaped information recording medium, wherein the laser beam emitted from the light source is condensed and irradiated to the information recording layer. An objective lens that can be deformed by an external force; a piezoelectric element that deforms by applying a voltage to apply a force to the objective lens; and a voltage that is applied to the piezoelectric element to deform the shape. An optical pickup device comprising: a control unit that deforms the objective lens by applying a force to control a focal position of the laser light. 5. The optical pickup device according to claim 4, wherein the control unit applies a voltage to the piezoelectric element so that the objective lens is deformed asymmetrically with respect to a center of the objective lens, and focuses the laser beam. An optical pickup device for controlling a position. 6. The optical pickup device according to claim 1, wherein the control unit controls a focal length of the laser beam in a focus direction. 7. The optical pickup device according to claim 1, wherein the control unit controls a focus direction of a tracking direction of the laser light. 8. The optical pickup device according to claim 1, wherein the control unit controls the focal length of the laser beam in the focus direction and the focus direction of the laser beam simultaneously. Pickup device. 9. The optical pickup device according to claim 1, wherein the control means controls the information recording layer for each of a plurality of disc-shaped information recording media having different depth positions of the information recording layer. An optical pickup device, wherein the focus position of the laser light is controlled by deforming the objective lens so that the laser light is focused. 10. The optical pickup device according to claim 9, wherein the plurality of disc-shaped information recording media are a DVD and a CD.
An optical pickup device, characterized in that: 11. An optical pickup device that reproduces a signal of an information recording layer of a disc-shaped information recording medium using a laser beam emitted from a light source, or reproduces and records a signal of the information recording layer. A concave reflecting mirror as a deformable concave mirror that reflects the laser light; one or more piezoelectric elements that deform the concave reflecting mirror; and applying a voltage to the piezoelectric element to deform the concave reflecting mirror. And a piezoelectric element control circuit for controlling a focal position of the laser beam. 12. The optical pickup device according to claim 11, wherein the plurality of piezoelectric elements are arranged around the concave reflecting mirror. 13. An optical pickup device that reproduces a signal of an information recording layer of a disc-shaped information recording medium using a laser beam emitted from a light source, or reproduces and records a signal of the information recording layer. A concave-shaped piezoelectric element, a laser-reflected, electrically-conductive coating coated on the inner surface of the piezoelectric element, and an electrically-conductive coating disposed on the outer surface of the concave reflecting mirror. A concave reflecting mirror as a deformable concave mirror formed by the plurality of electrodes, and applying a voltage between the conductive coating and the plurality of electrodes to deform the piezoelectric element on the concave surface. An optical pickup device, comprising: a piezoelectric element control circuit for deforming the concave reflecting mirror and controlling a focal position of laser light. 14. The optical pickup device according to claim 11, wherein the piezoelectric element control circuit controls a focal length of a laser beam in a focus direction. apparatus. 15. The optical pickup device according to claim 11, wherein the piezoelectric element control circuit controls a focus direction of a tracking direction of the laser beam. apparatus. 16. The optical pickup device according to claim 11, wherein the piezoelectric element control circuit controls a focal length of a laser beam in a focus direction and a focal direction of a tracking direction. And an optical pickup device. 17. The optical pickup device according to claim 11, wherein the piezoelectric element control circuit controls a plurality of disk-shaped information recording media having different information recording layer depth positions. An optical pickup device for controlling the focal position of the laser light by deforming the concave reflecting mirror so that the laser light is focused on each information recording layer. 18. The optical pickup device according to claim 17, wherein the plurality of disc-shaped information recording media are a DVD and a CD.
An optical pickup device, characterized in that: 19. The optical pickup device according to claim 11, wherein the concave reflecting mirror is formed as a set of a plurality of concave portions, and a plurality of focal points of the laser light are formed. An optical pickup device characterized by generating. 20. The optical pickup device according to claim 19, wherein a plurality of focal positions of laser light generated by the concave reflecting mirror are controlled independently. 21. The optical pickup device according to claim 20, wherein a plurality of focal points of the laser light generated by the concave reflecting mirror are independently focused on a plurality of tracks of a disc-shaped information recording medium, thereby simultaneously. An optical pickup device for reading a plurality of recording tracks. 22. The optical pickup device according to claim 21, wherein when a single laser focus is required, only a single focus among a plurality of focuses of the laser light generated by the concave reflecting mirror is used. An optical pickup device, which focuses on a disc-shaped information recording medium and prevents another laser beam from being focused on the disc-shaped information recording medium. 23. The optical pickup device according to claim 19, wherein the concave reflecting mirror includes a laser beam directed to a focal point of a signal recording layer of a disk-shaped recording medium, and a laser beam directed from the focal point. An optical pickup device, wherein reflected laser light is reflected by a concave portion which is line-symmetric or point-symmetric with respect to a center line or a center point of the concave reflecting mirror. 24. The optical pickup device according to claim 19, wherein the laser light emitted from the light source and incident on the concave reflecting mirror is close to a diameter of the concave reflecting mirror. An optical pickup device, which is a laser beam having a thickness.