JPH10233026A - Optical pickup and optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute a compact optical disk array by using plural light beams branched by an optical branching means and recording or reproducing a signal on the signal recording surfaces of the corresponding disks. SOLUTION: The light beams from one of the semiconductor elements of an optical section 21 are reflected by a bending mirror 22 and are made incident on a combination prism 23. Then, the beams are reflected to an optical disk D1 by the dichroic filter of the prism 23 and are converged on the disk D1 through an objective lens 24. The returned light beams from the disk D1 are converged on one of the photodetectors of the section 21. In order to reproduce the signals on an optical disk D2, the light beams from the other semiconductor laser elements of the section 21 are converged on the disk D2 through the prism 23. The returned light beams from the disk D2 are converged on the other photodetector of the section 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recording and / or recording signals from an optical disk such as an optical disk, a magneto-optical disk, and a phase change disk (hereinafter referred to as "optical disk").
Also, the present invention relates to an optical pickup for reproduction and an optical disk device provided with the optical pickup.

[0002]

2. Description of the Related Art Conventionally, an optical pickup for an optical disk is constructed, for example, as shown in FIG. FIG.
, An optical pickup 1 comprises a grating 3, a beam splitter 4, and a beam splitter 4, which are sequentially arranged in an optical path of a light beam emitted from a semiconductor laser element 2 as a light source.
It comprises a collimator lens 5, an objective lens 6, and a photodetector 7 disposed in a separation optical path of return light from the optical disc D that has passed through the beam splitter 4.

In the optical pickup 1 having such a configuration, the light beam from the semiconductor laser element 2 passes through the grating 3, is reflected by the beam splitter 4, and is converted into parallel light by a collimator lens 5. The signal is recorded on the signal recording surface of the optical disc D by the objective lens 6. Then, the return light beam reflected by the signal recording surface of the optical disk D again passes through the objective lens 6, the collimator lens 5, and the beam splitter 4, and is received by the light receiving surface of the photodetector 7, and the recording signal is detected. It is supposed to be.

Then, the light beam from the semiconductor laser element 2 forms a spot at a correct position on the signal recording surface of the optical disc D, so that the recorded signal can be reproduced accurately.
The objective lens 6 is finely moved based on a predetermined servo signal. The servo of the objective lens 6 includes a tracking servo for finely moving the objective lens 7 along a radial direction of the optical disc D with respect to a recording track of the optical disc D, and a servo for approaching a signal recording surface of the optical disc D along the optical axis. Focusing servo for finely moving the objective lens 6 in the direction of separation is performed.

[0005]

When an optical disk is used as, for example, an auxiliary recording device of a computer, an optical pickup for recording and reproducing signals is constructed as described above, as compared with a hard disk drive. Therefore, it is larger than a magnetic head in a hard disk drive. For this reason, when configuring an optical disk array, in the case of a configuration in which an optical pickup is provided for each of a plurality of optical disks, a number of relatively expensive optical pickups are required, and
There is a problem that the entire optical disk array becomes large. Therefore, a so-called jukebox type optical disk array in which one optical disk to be recorded or reproduced is taken out and recording or reproduction is performed by one optical pickup is generally used.

However, such a jukebox type optical disk array requires a mechanism for transporting the optical disk to a predetermined position with respect to the optical pickup, so that the structure becomes complicated and the entire apparatus becomes large. And it is expensive. Therefore, it is only used for a special large-capacity file server and is not practical.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide an optical pickup and an optical disk apparatus using the same, which can constitute a small optical disk array.

[0008]

According to the present invention, there is provided a light source for emitting a light beam, light branching means for branching the light beam emitted from the light source into a plurality of light beams, Each light beam split by the splitting means is
A light focusing means for focusing on each signal recording surface of a plurality of optical discs, a light separating means arranged between the light source and the light branching means, and a signal recording surface of the optical disc separated by the light separating means. And a photodetector having a light receiving portion for receiving the return light beam.

According to the above configuration, recording or reproduction of a signal on or from a signal recording surface of a corresponding optical disk is performed by a plurality of (for example, two) light beams branched by the light branching means. Therefore, when configuring an optical disk array, it is not necessary to provide an optical pickup having a conventional configuration for each optical disk, and one optical pickup according to the present invention may be provided for a plurality of (for example, two) optical disks. I just need.

When the light splitting means is, for example, a dichroic prism or a wavelength-selective prism so as to split light beams of different wavelengths, recording or reproduction of different types of optical discs is performed.

In the case where the light branching means is a reversible electrodeposition device or an electrochromic device, recording or reproduction of a plurality of optical disks of the same type is performed by switching light beams by these light branching means. become.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS.
The embodiment described below is a preferred specific example of the present invention, and thus various technically preferable limitations are added. However, the scope of the present invention particularly limits the present invention in the following description. The embodiment is not limited to these embodiments unless otherwise stated.

FIG. 1 shows the basic configuration of an embodiment of an optical disk device incorporating an optical pickup according to the present invention. In FIG. 1, an optical disk device 10 includes a spindle motor 12 as a driving means for rotatingly driving an optical disk 11, and a signal recording surface of the rotating optical disk 11 which is irradiated with a light beam to record a signal. An optical pickup 20 for reproducing a recording signal by a return light beam from the optical pickup 20 and a control unit 13 for controlling the optical pickup 20 are provided. Here, the control unit 13 includes an optical disk controller 14, a signal demodulator 15, an error correction circuit 16, an interface 17, a head access control unit 18, and a servo circuit 19.

An optical disk controller 14 controls the drive of the spindle motor 12 at a predetermined rotation speed. The signal demodulator 15 demodulates the recording signal from the optical pickup 20, corrects the error, and sends the signal to an external computer or the like via the interface 17. Thus, an external computer or the like can receive a signal recorded on the optical disk 11 as a reproduction signal.

The head access control section 18 moves the optical pickup 20 to a predetermined recording track on the optical disk 11, for example, by a track jump or the like. The servo circuit 19 moves the objective lens held by the biaxial actuator of the optical pickup 20 in the focusing direction and the tracking direction at the moved predetermined position.

In this embodiment, for example, two optical disks of the same type or optical disks D1 and D2 corresponding to two different wavelengths are used in this embodiment. In the case of optical discs corresponding to different wavelengths,
For example, one optical disk D1 is compatible with a light source having a wavelength of 780 nm, and is, for example, a compact disk (C
D) or a writable CD such as a CD-R. The other optical disk D2 corresponds to a light source having a wavelength of 650 nm, and is, for example, a high-density recording format, a CD, or a CD-R.

Further, the respective components shown in FIG. 1 are provided for the optical discs D1 and D2, respectively. The feature of the present embodiment is that the optical pickup 20 is one common one.

FIG. 2 shows a configuration of an optical pickup incorporated in the optical disk device 10. In FIG. 2, an optical pickup 20 includes an optical unit 21 including a light source and a light detection unit for two optical discs D1 and D2 that are disposed to face each other and that are each rotationally driven by a spindle motor (not shown). Folding mirror 22
, A combination prism 23 as a light branching unit, and optical discs D1, D
2 objective lenses 24 and 25 respectively disposed in two optical paths associated with each other.

The combination prism 23 has an incident surface 23a perpendicular to the light beam L1 from the light source of the optical section 21 as shown in FIG.
The two prisms 23d and 23e are bonded to each other so as to have boundary surfaces 23b and 23c inclined by 45 degrees in opposite directions to each other with respect to 3a. In the case shown in the figure, the boundary surface 23b is a bonding surface of the two prisms 23d and 23e, and is inclined toward the optical disk D1 and the boundary surface 23b is inclined toward the optical disk D2.

Here, the boundary surface 23 of the combination prism 23
b, as shown in FIG. 3, the two prisms 23d, 2d
A dichroic filter 23f made of a dichroic film is interposed between 3e. Thus, the combination prism 23 is configured as a dichroic prism. The dichroic filter 23f is
For example, it has dichroic characteristics as shown in FIG. 4 and has two different wavelengths (for example, 780 nm and 650 nm).
nm) can be separated. In the illustrated case, the dichroic filter 23f has a wavelength of 7
It is configured to substantially reflect (about 80 percent) light of 80 nm and substantially transmit light of wavelength 650 nm, but the reflection and transmission characteristics may be reversed.

Thus, of the light beam L1 from the light source of the optical unit 21, the light having the wavelength of 780 nm is reflected by the dichroic filter 23f, converged on the signal recording surface of the optical disk D1 via the objective lens 24, and Wavelength 6
The 50 nm light is totally reflected by the inner surface 23c of the combination prism 23, then exits from the prism 23, and
5, the light is focused on the signal recording surface of the optical disk D2.

Here, each of the objective lenses 24 and 25 is
The lens is a convex lens, and is movably supported in a biaxial direction by, for example, a known biaxial actuator (not shown) so as to be adjusted in a biaxial direction with respect to the optical disks D1 and D2.

Next, the optical section 21 is configured as shown in FIG. 5, for example. In FIG. 5, the optical unit 21
Are two semiconductor laser elements 21a and 21 as light sources.
b, a dichroic prism 21c having the same dichroic filter as the combination prism 23 described above,
A half mirror prism 21d as a light separating means, a collimator lens 21e, a dichroic prism 21f having the same dichroic filter as the combination prism 23, and a dichroic prism 21
multi-lens 2 disposed in each optical path branched by f
1g, 21h and photodetectors 21i, 21j.

Here, the semiconductor laser elements 21a, 21
Numeral 1b denotes a light emitting element utilizing the recombination light emission of a semiconductor, and a laser beam of a predetermined wavelength, for example, a wavelength of 780, respectively.
and 650 nm light beams.

The above dichroic prisms 21c and 2
1f is 780 each as in the case of the combination prism 23.
It is configured to reflect a light beam of nm and transmit light of 650 nm.

The half mirror prism 21d has a half mirror surface inclined at an angle of 45 degrees with respect to the optical path, acts as a non-polarizing beam splitter, transmits a part of the laser light from the dichroic prism 21c, and And a part of the return light from the optical disks D1 and D2.

The collimator lens 21e is a convex lens, and includes a dichroic prism 21c and a half mirror prism 2 from the semiconductor laser elements 21a and 21b.
The light beam incident via 1d is converted into parallel light.

Each of the photodetectors 21i and 21j is provided from the optical discs D1 and D2 from the multi-lenses 21g and 21g, respectively.
The light receiving unit is configured to have a light receiving unit for the return light beam that enters through h.

The optical section 21, the bending mirror 22, and the combination prism 23 are moved along a guide (not shown) provided on the optical pickup 20 by the optical disks D1, D2.
D2 is fixedly held by an optical base (not shown) movably supported in the radial direction.

The optical disk device 10 incorporating the optical pickup 20 according to the present embodiment is configured as described above, and operates as follows.

First, in FIG.
When reproducing 1, the optical disk D1 of the optical disk device 10 is rotated to rotate the optical disk D1 by rotating the spindle motor 12 associated with the optical disk D1. Then, by moving the entire optical pickup 20 in the radial direction of the optical disc D1 along a guide (not shown), the optical axis of the objective lens 24 of the optical pickup 20 becomes
Access is performed by moving the optical disc D1 to a desired track position.

In this state, a light beam having a wavelength of, for example, 780 nm from the semiconductor laser element 21a of the optical unit 21 shown in FIG. 5 is reflected by the dichroic prism 21c, passes through the half mirror prism 21d, and passes through the collimator lens 2
After being changed into parallel light by 1e, the light is reflected by the bending mirror 22 shown in FIG. The light beam is reflected toward the optical disk D1 by the dichroic filter 23f of the combination prism 23, and is focused on the signal recording surface of the optical disk D1 via the objective lens 24.

The return light from the optical disk D1 is reflected again by the objective lens 24 and the dichroic filter 23f of the combination prism 23, passes through the bending mirror 22 and the collimator lens 21e, and returns to the half mirror prism 21d.
Incident on. Then, the return light beam is reflected by the half mirror prism 21d, further reflected by the dichroic prism 21f, and converged on the photodetector 21i via the multi-lens 21g. Thereby, the photodetector 21i
, The recording signal of the optical disk D1 is reproduced.

At this time, the signal demodulator 15 is
The tracking error signal and the focusing error signal are detected based on the detection signal from i.
Then, the servo circuit 19 servo-controls a biaxial actuator (not shown) for the objective lens 24 via the optical disk drive controller 14. Thus, the objective lens 24 is moved and adjusted in the biaxial directions with respect to the optical disc D1.

Next, when reproducing the other optical disk D2, the spindle motor 12 associated with the optical disk D2 of the optical disk device 10 is rotated, whereby the optical disk D2 in FIG. 2 is driven to rotate. Then, the optical pickup 20 is moved in the radial direction of the optical disc D2 along a guide (not shown), so that the optical axis of the objective lens 25 of the optical pickup 20 is changed to the optical disc D2.
Is accessed by moving to the desired track position.

In this state, a light beam having a wavelength of, for example, 650 nm from the semiconductor laser element 21b of the optical unit 21 shown in FIG. 5 passes through the dichroic prism 21c, further passes through the half mirror prism 21d, and is collimated by the collimator lens 21e. After being changed to light, the light is reflected by the bending mirror 22 and enters the combination prism 23. Then, the light beam passes through the dichroic filter 23f of the combination prism 23 in FIG.
Is reflected toward the optical disc D2 by the objective lens 25.
Is focused on the signal recording surface of the optical disk D2.

The return light from the optical disk D2 is reflected again by the boundary surface 23c between the objective lens 25 and the combination prism 23, and enters the half mirror prism 21d via the bending mirror 22 and the collimator lens 21e. The return light beam is reflected by the half mirror prism 21d, further passes through the dichroic prism 21f, and is focused on the photodetector 21j via the multi-lens 21h. Thereby, the recording signal of the optical disc D2 is reproduced based on the detection signal of the photodetector 21j.

At this time, the signal demodulator 15 is
The tracking error signal and the focusing error signal are detected based on the detection signal from j.
Then, the servo circuit 19 servo-controls a biaxial actuator (not shown) for the objective lens 25 via the optical disk drive controller 14. Thus, the objective lens 25 is moved and adjusted in the biaxial directions with respect to the optical disc D2.

Thus, according to the optical disc apparatus 10 and the optical pickup 20, two different types of optical discs D1 and D2 are formed by using the common optical section 21 with light beams having different wavelengths, for example, 780 nm and 650 nm. At the same time as playback, both optical discs D1 and D2 can be played back simultaneously.

FIG. 6 shows another configuration of the optical unit in the optical disk device 10 and the optical pickup 20. In FIG. 6, the optical unit 26 includes two semiconductor laser elements 26a and 26b as light sources, a dichroic prism 26c having the same dichroic filter as the combination prism 23 described above, a half mirror 26d,
A collimator lens 26e, a multi-lens 26g disposed on the optical path of the return light beam split by a half mirror 26d as light separating means, and one photodetector 26
h.

The dichroic prism 26c, like the combination prism 23, reflects a 780 nm light beam and transmits 650 nm light, respectively.
It is configured.

The half mirror 26d has a half mirror surface inclined at an angle of 45 degrees with respect to the optical path.
It functions as a non-polarizing beam splitter, and reflects a part of the laser light from the dichroic prism 26c and transmits a part of the return light from the optical disks D1 and D2.

Each of the photodetectors 26h is an optical disk D
It is configured to have a light receiving unit for return light beams that are respectively incident from D1 and D2 via the multi-lens 26g.

When the optical section 26 having such a configuration is used, return light from each of the optical discs D1 and D2 enters the half mirror 26d via the collimator lens 26e, and a part of the return light is transmitted. , Through the multi-lens 26g, to the photodetector 26h. Therefore, the recording signal of the optical disk D1 or D2 is reproduced based on the detection signal of the photodetector 26h.

At this time, the signal demodulator 15 is provided with a photodetector 26.
h, a tracking error signal is detected by the detection signal, and a focusing error signal is detected by the astigmatism method. Then, the servo circuit 19 controls the objective lens 24 via the optical disk drive controller 14.
Or, servo-control a two-axis actuator (not shown) for 25. Thereby, the objective lens 24 or 2
5 is moved and adjusted in two axial directions with respect to the optical disk D1 or D2. In this case, one photodetector 2
Since 6h is used for reproducing the recording signals of both optical disks D1 and D2, it is not possible to reproduce both optical disks at the same time, and only one optical disk is selectively reproduced.

FIG. 7 shows a second embodiment of the optical pickup according to the present invention. In FIG. 7, the optical pickup 30 differs from the optical pickup 20 of FIG. That is, the combination prism 23
Instead, the configuration is different only in that a so-called cube-type wavelength-selective prism 31 having a square cross section is provided.

The wavelength-selective prism 31 has two dichroic filters 31a and 31b inclined at an angle of 45 degrees in directions opposite to each other with respect to the incident light beam. One dichroic filter 31a has a wavelength of 780 nm, for example. The light beam is reflected toward the optical disk D1, and the other dichroic filter 31b
Transmits a light beam having a wavelength of 650 nm to the optical disc D2
It is constituted so that it may reflect toward.

According to the optical pickup 30 having such a structure, the recording signal of the optical disk D1 and / or the optical disk D2 is reproduced in exactly the same manner as the optical pickup 20 of FIG. In this case, since the cross section of the wavelength-selective prism 31 is formed to be square, the optical pickup 30 and the entire optical disk device 10 are configured to be small.

FIG. 8 shows a third embodiment of the optical pickup according to the present invention. 8, the optical pickup 40 differs from the optical pickup 20 of FIG. That is, in this embodiment, instead of the combination prism 23 of FIG. 2, a combination prism 41 using a reversible electro-deposition device (hereinafter, referred to as RED) is provided as a filter for wavelength selection.

As shown in FIG. 9, the combination prism 41 has two prisms 23d and 23e having the same configuration as the combination prism 23, and has a boundary surface 23.
The above-described RED 42 is sandwiched between b. The RED 42 has a structure in which a solute 42 a is
2c. The RED 42 is driven by a drive power source (see FIG. 8) 43 to transmit the transparent electrodes 42 b and 42.
The transparent electrode c is transparent when no voltage is applied, but when a voltage is applied between the two transparent electrodes 42b and 42c, the solute 42a precipitates on the surface and the surface becomes mirror-like. Thus, the incident light beam L1 is reflected on the surface of the RED.

In this case, the switching of the light beam for the optical disks D1 and D2 is performed by turning on and off the drive voltage from the drive power supply 43 applied to the RED 42, so that the optical unit 21 is also shown in FIG. 10, for example. Simplified as follows. In FIG. 10, an optical unit 44 includes one semiconductor laser element 44a as a light source, a half mirror prism 44b, a collimator lens 44c, and a multi-beam disposed in an optical path of a return light beam branched by the half mirror prism 44b. Lens 44d and photodetector 4
4e.

According to the optical pickup 40 having such a configuration, when reproducing the optical disk D1, the drive power supply 43 is turned on, a drive voltage is applied to the RED 42, and the surface is mirror-finished. From this state, the light beam from the semiconductor laser element 44a of the optical section 44 is transmitted through the half mirror prism 44b and converted into parallel light by the collimator lens 44c.
And is incident on the combination prism 41. At this time, since the surface of the RED 44 of the combination prism 41 has a mirror-like surface, the light beam is reflected by the surface of the RED 44 and passes through the objective lens 24 to the optical disk D.
Focus on one signal recording surface.

The return light from the optical disk D1 is reflected again by the objective lens 24, the surface of the RED 44 of the combination prism 41, and is reflected by the bending mirror 22 and the collimator lens 44.
The light is incident on the half mirror prism 44b via the line c.
The return light beam is transmitted to the half mirror prism 44b.
Is reflected by the photodetector 4 via the multi-lens 44d.
Focus on 4e. Thereby, the recording signal of the optical disc D1 is reproduced based on the detection signal of the photodetector 44e.

When reproducing the optical disk D2, the drive power supply 43 is turned off and the drive voltage is reduced to RED42.
Do not apply to From this state, the light beam from the semiconductor laser element 44a of the optical unit 44 passes through the half mirror prism 44b, is converted into parallel light by the collimator lens 44c, is reflected by the bending mirror 22, and is reflected by the combination prism 41. Incident on. At this time, since the RED 44 of the combination prism 41 is transparent, the light beam
The light passes through the RED 44, is reflected by the boundary surface 23c, and is focused on the signal recording surface of the optical disk D2 via the objective lens 25. The return light from the optical disc D2 is reflected again by the boundary surface 23c of the objective lens 25 and the combination prism 41,
The light enters the half mirror prism 44b via the bending mirror 22 and the collimator lens 44c. And
The return light beam is reflected by the half mirror prism 44b, and is focused on the photodetector 44e via the multi-lens 44d. Thereby, the recording signal of the optical disc D2 is reproduced based on the detection signal of the photodetector 44e.

In the case of this embodiment, the switching of the light beam is performed by turning on and off the drive voltage to the RED 42 and the reproduction of the recording signals of the optical disks D1 and D2 is performed by the light beam from the same semiconductor laser element 44a. Optical disks of the same type are handled as the optical disks D1 and D2. When the optical unit 21 or 26 described above is used instead of the optical unit 44, different types of optical disks can be handled as the optical disks D1 and D2, similarly to the optical pickups 20 and 30 described above.

FIG. 11 shows a fourth embodiment of the optical pickup according to the present invention. In FIG. 11, an optical pickup 50 is different from the optical pickup 40 of FIG. 8 in that an electrochromic device (hereinafter, referred to as an EC device) is used as a filter for selecting a wavelength, instead of the combination prism 41 as a light branching unit. Is provided.

As shown in FIG. 12, the combination prism 51 has two prisms 23d and 23e having the same configuration as the combination prism 23, and has a boundary surface 2
3b is configured as a half mirror surface. further,
The exit surface 23g of the incident light beam L1 reflected at the boundary surface 23b and the incident light beam L reflected at the boundary surface 23c
Each of the EC devices 5
2, 53 are attached. This EC device 5
Each of the reference numerals 2 and 53 is made of, for example, a tantan oxide, and has a high transmittance in a state where no voltage is applied by being driven by a drive power supply (see FIG. 11) 54. Then, the transmittance decreases.

According to the optical pickup 50 having such a configuration, when the optical disk D1 is reproduced, the drive power supply 54 is controlled to apply a drive voltage only to the EC device 53 to reduce the transmittance. Keep it. From this state, the light beam from the semiconductor laser element 44 a of the optical unit 44 is reflected by the bending mirror 22 and enters the combination prism 51. At this time, the EC of the combination prism 51
Device 52 has no voltage applied and has a relatively high transmittance, and EC device 53 has voltage applied and has a relatively low transmittance.

Therefore, a part of the light beam incident on the combination prism 51 is reflected by the half mirror surface, and
The light passes through the device 52 and is focused on the signal recording surface of the optical disk D1 via the objective lens 24. The return light from the optical disk D1 is again transmitted to the objective lens 24, the combination prism 5
The light is reflected by the half mirror surface, enters the optical unit 44 via the bending mirror 22, and is focused on the photodetector 44e. Thereby, the recording signal of the optical disc D1 is reproduced based on the detection signal of the photodetector 44e.

When reproducing the optical disk D2, the driving power supply 54 is controlled to apply a driving voltage only to the EC device 52 to reduce its transmittance. From this state, the light beam from the semiconductor laser element 44 a of the optical unit 44 is reflected by the bending mirror 22 and enters the combination prism 51. At this time, the combination prism 51
The EC device 52 has a relatively low transmittance when a voltage is applied, and the EC device 52 has a relatively high transmittance when no voltage is applied.

Accordingly, a part of the light beam incident on the combination prism 51 is transmitted through the half mirror surface, further transmitted through the EC device 53, and reflected by the boundary surface 23c. Focus on the signal recording surface of the optical disc D2. The return light from the optical disc D2 is reflected again by the boundary surface 21c between the objective lens 25 and the combination prism 51, enters the optical unit 44 via the bending mirror 22, and is focused on the photodetector 44e. Thereby, the recording signal of the optical disc D2 is reproduced based on the detection signal of the photodetector 44e.

In the case of this embodiment, the switching of the light beam is performed by turning on and off the drive voltage for the EC devices 52 and 53, and the same semiconductor laser element 4 is used.
4a, the recording signals of the optical disks D1 and D2 are reproduced by the light beam from the optical disks D1 and D2.
In this case, the same type of optical disk is handled. Note that, instead of the optical unit 44, the optical unit 21 described above is used.
Or 26 is used, the optical discs D1, D
As No. 2, different types of optical discs are handled as in the case of the optical pickups 20 and 30 described above.

FIG. 13 shows a fifth embodiment of the optical pickup according to the present invention. 13, the optical pickup 60 differs from the optical pickup 40 of FIG. 8 in the light branching means. That is, in this embodiment, a bending mirror 61 that is mechanically driven to rotate is provided instead of the combination prism 41 in FIG.

The bending mirror 61 is arranged, for example, so that its reflection surface 61a is inclined at an angle of 45 degrees with respect to the incident light reflected from the optical unit 44 and the bending mirror 22. A driving device 62 disposed between the two optical discs D1 and D2 passes through the center of the bending mirror 22 and moves around a virtual rotation axis parallel to the incident light.
As shown in FIG. Thereby, the folding mirror 61 has its reflecting surface 61 in the case shown in the figure.
a reflects the incident light toward the optical disk D1 and is rotated by 180 degrees by the driving device 62, so that the reflection surface 61a reflects the incident light toward the optical disk D2. The folding mirror 6
1 is configured as a triangular prism in the illustrated case, but may be a flat mirror. In FIG. 13, the bending mirror 61 may rotate in the direction of arrow A2 around a virtual rotation axis parallel to the optical axis from the bending mirror 61 to the optical disk D1.

According to the optical pickup 60 having such a configuration, when reproducing the optical disk D1, the driving device 62 is controlled to rotate the bending mirror 61 to the illustrated position. From this state, the light beam from the semiconductor laser element 44 a of the optical unit 44 is reflected by the bending mirror 22 and enters the bending mirror 61. Then, the light beam is reflected by the reflection surface 61a, and the objective lens 24
, And converges on the signal recording surface of the optical disc D1. The return light from the optical disc D1 again enters the optical unit 44 via the objective lens 24, the bending mirror 61, and the bending mirror 22, and is focused on the photodetector 44e. Thereby, the recording signal of the optical disc D1 is reproduced based on the detection signal of the photodetector 44e.

When reproducing the optical disk D2, the drive device 62 is controlled to rotate the bending mirror 61 by 180 degrees to the opposite side to the position shown in the figure. From this state, the light beam from the semiconductor laser element 44a of the optical unit 44 is reflected by the bending mirror 22 and
Incident on 1. Then, the light beam is reflected on its reflection surface 61a.
Reflected by the optical disk D2 via the objective lens 25.
Focus on the signal recording surface. The return light from the optical disk D2 enters the optical unit 44 again via the objective lens 25, the bending mirror 61, and the bending mirror 22, and the light detector 4
Focus on 4e. Thereby, the recording signal of the optical disc D2 is reproduced based on the detection signal of the photodetector 44e.

As described above, according to each of the above embodiments,
With a plurality (for example, two) of light beams branched by the light branching means, recording or reproduction of a signal on or from a signal recording surface of a corresponding optical disc is performed. Therefore, when configuring an optical disk array, it is not necessary to provide an optical pickup having a conventional configuration for each optical disk, and one optical pickup may be provided for a plurality (for example, two) of optical disks. As a result, when configuring an optical disk array, the number of necessary optical pickups is reduced as compared with the conventional optical disk array, so that the entire apparatus is configured to be small and the cost is reduced.

In the optical disk device 10 and the optical pickups 40 and 50 according to the above embodiment, the RED 44, the EC device 52, and the
Although the device 53 is used, a device having the same effect as the RED, such as a liquid crystal, is used instead of the RED 44, and the wavelength-selective liquid crystal and glossiness are removed instead of the EC devices 52, 53. RED is also used.

Further, in the above embodiment, the optical disk device 10 and the optical pickups 20, 30, 40, 50, which reproduce the two optical disks D1 and D2 are used.
Although 60 has been described, it is apparent that the present invention is not limited to this, and can be applied to an optical disk device and an optical pickup configured to reproduce three or more disks.

[0070]

As described above, according to the present invention, it is possible to provide an optical pickup and an optical disk apparatus using the same, which can constitute a small optical disk array.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of an embodiment of an optical disk device incorporating an optical pickup according to the present invention.

FIG. 2 is a schematic side view showing a first embodiment of an optical pickup in the optical disk device of FIG. 1;

FIG. 3 is an enlarged side view illustrating a configuration of a combination prism used in the optical pickup of FIG. 2;

FIG. 4 is a graph showing characteristics of a dichroic filter in the combination prism of FIG.

FIG. 5 is a schematic side view showing a first configuration of an optical unit used in the optical pickup of FIG. 2;

FIG. 6 is a schematic side view showing a second configuration of the optical unit used in the optical pickup of FIG.

FIG. 7 is a schematic side view showing a second embodiment of the optical pickup according to the present invention.

FIG. 8 is a schematic side view showing a third embodiment of the optical pickup according to the present invention.

FIG. 9 is an enlarged side view showing a configuration of a combination prism used in the optical pickup of FIG.

FIG. 10 is a schematic side view showing a configuration of an optical unit used in the optical pickup of FIG.

FIG. 11 is a schematic side view showing a fourth embodiment of the optical pickup according to the present invention.

FIG. 12 is an enlarged side view illustrating a configuration of a combination prism used in the optical pickup of FIG. 11;

FIG. 13 is a schematic side view showing a fifth embodiment of the optical pickup according to the present invention.

FIG. 14 is a side view showing an optical system in an example of a conventional optical pickup.

[Brief Description of Reference Codes] 10 optical disk device, 11 optical disk, 1
2 ... Spindle motor, 13 ... Control unit, 14.
..Optical disk drive controller, 15: signal demodulator, 16: error correction circuit, 17: interface, 18: head access control unit, 20, 3
0, 40, 50, 60 ... optical pickup, 21,
26, 44: Optical section, 31: Wavelength selective prism, 41: Combination prism, 42: RED, 4
3 ... drive power supply, 51 ... combination prism, 52,
53: EC device, 54: Drive power supply, 61
..Bending mirrors, 62 ... Drive devices.

Claims (13)

[Claims] A light source that emits a light beam; a light branching unit that branches the light beam emitted from the light source into a plurality of light beams; Light converging means for converging light on each of the signal recording surfaces, light separating means disposed between the light source and the light branching means, and return light from the signal recording surface of the optical disc separated by the light separating means. An optical pickup comprising: a photodetector having a light receiving unit that receives a beam. 2. A light source for emitting a light beam, light branching means for splitting a light beam emitted from the light source into two light beams, and each light beam split by the light splitting means is divided into two light beams. A light focusing means for focusing on each signal recording surface of the optical disc; a light separating means provided between the light source and the light branching means; and a return from the signal recording face of the optical disc separated by the light separating means. An optical pickup comprising: a photodetector having a light receiving unit that receives a light beam. 3. The optical pickup according to claim 2, wherein the light splitting means is configured to split light beams having different wavelengths. 4. The optical pickup according to claim 3, wherein said light splitting means is a dichroic prism. 5. The optical pickup according to claim 3, wherein the light branching unit is a wavelength-selective prism. 6. The optical pickup according to claim 2, wherein the light branching unit is a reversible electro-deposition device. 7. The optical pickup according to claim 2, wherein the light branching unit is an electrochromic device. 8. The optical pickup according to claim 1, wherein the light source includes two light sources that emit light beams having different wavelengths, and the light branching unit includes a wavelength separation filter. 9. The optical pickup according to claim 8, wherein the light branching unit has a wavelength selective filter for returning light from each optical disk. 10. The optical pickup according to claim 2, wherein the light splitting means is a bending mirror that is mechanically rotated around a virtual rotation axis parallel to an incident optical axis. 11. The optical pickup according to claim 2, wherein the two optical disks are the same type of optical disk. 12. The optical pickup according to claim 2, wherein the two optical disks are different types of optical disks. 13. A light splitting means for splitting a light beam emitted from a light source into a plurality of light beams, and each light beam split by the light splitting means is focused on each signal recording surface of a plurality of optical disks. A light focusing means; an electromagnetic driving means for moving the light focusing means in two directions of tracking and focusing; a light detecting means having a light receiving portion for receiving a return light beam from a signal recording surface of each optical disc; An optical disc device comprising: an arithmetic unit that obtains a servo signal based on a signal from a light receiving unit of a detecting unit; and a servo unit that supplies a drive current to the electromagnetic driving unit based on the servo signal.