JPH11273109A - Optical pickup - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an in expensive and small-sized optical pickup capable of condensing a laser beam of a sufficient light quantity for recording surfaces of plural recording media with a simple constitution. SOLUTION: The optical pickup 100 recording/reproducing information on/ from the recording surfaces of respective recording media by irradiating the laser beam to plural recording media 112, 112' is provided with a galvano-mirror 300 selectively reflecting the laser beam from a light source 104 toward any one side of plural recording media and adjusting beam spot positions on the recording surfaces of respective recording media.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup capable of performing tracking control using, for example, a galvanomirror and recording and reproducing information on and from recording surfaces of a plurality of recording media.

[0002]

2. Description of the Related Art Conventionally, for example, an optical pickup disclosed in Japanese Patent Application Laid-Open No. 6-2749228 has a pickup section controlled to move radially along the recording surfaces of first and second recording media, A light emitting / receiving unit capable of emitting a reproducing laser beam and receiving reflected light from the recording surfaces of the first and second recording media (first related art).

In the first prior art, a pickup section includes two first and second objective lenses disposed opposite to recording surfaces of first and second recording media, respectively, and a light emitting and receiving section. From the first and the second objective lens can be reflected,
A rotating mirror is provided that can reflect return light (reflected light from the recording surface) taken in via the first and second objective lenses toward the light emitting / receiving unit.

In such a configuration, first, a rotary mirror is rotated so as to reflect a laser beam toward a first objective lens. Then, when the recording or reproducing laser light is emitted from the light emitting / receiving unit, the recording or reproducing laser light is focused on the recording surface of the first recording medium from the rotating mirror via the first objective lens. Light. As a result, information is recorded and reproduced on the recording surface of the first recording medium. Next, the rotating mirror is rotated so as to reflect the laser light toward the second objective lens.
When the recording or reproducing laser beam is emitted from the light emitting / receiving unit, the recording or reproducing laser beam is focused on the recording surface of the second recording medium from the rotating mirror via the second objective lens. Light. As a result, information is recorded and reproduced on the recording surface of the second recording medium.

[0005] For example, in the document "Functional design and application of an optical system using diffractive optics" published by Yuzo Ono, it is specified that a laser beam from a light emitting / receiving unit is divided into two vertically. A roof-type mirror fixed at a position is disclosed, and the roof-type mirror can irradiate a laser beam split into two upper and lower portions on a recording medium arranged vertically (second conventional example). Technology).

[0006]

However, in the first prior art, in order to perform tracking control of laser light on a recording surface, a driving mechanism for moving a pickup portion in a radial direction and a rotating mirror are further provided. Since a drive mechanism that rotates a predetermined amount in the direction is required separately,
The device configuration becomes complicated, and the number of parts increases, which not only increases the size of the device but also increases the manufacturing cost.

In the second prior art, since the roof type mirror is fixed, when such an optical system is used for an optical pickup, a tracking control means is separately required. For this reason, similarly to the first related art, there is a problem that the number of components increases and the device becomes large. Further, in the second prior art, since the laser light is divided into two parts via the roof type mirror, the amount of the laser light applied to each recording medium is reduced by half,
In some cases, it becomes difficult to secure recording and reproduction laser beams having a sufficient light amount for recording and reproduction of information. In this case, a laser light source having a large output is required to secure recording and reproducing laser beams having a sufficient light amount for recording and reproducing information, and as a result, the manufacturing cost of the device increases. Problem.

An object of the present invention is to solve such a problem, and an object of the present invention is to collect a sufficient amount of laser light on the recording surfaces of a plurality of recording media with a simple configuration. It is an object of the present invention to provide a small-sized optical pickup at a low cost, which can be realized.

[0009]

In order to achieve the above object, the present invention provides a method of recording information on a recording surface of each recording medium by irradiating a plurality of recording media with laser light. An optical pickup capable of performing reproduction, wherein a laser beam from a light source is selectively reflected toward one of the plurality of recording media, and a beam spot is formed on a recording surface of each of the recording media. It has one galvanometer mirror whose position can be adjusted.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical pickup according to an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 schematically shows the configuration of an optical pickup 100 having a telecentric optical system as an example of the present invention, and FIG. 2 shows that the optical pickup 100 is disposed on a swing arm 102. The state is shown.

As shown in FIGS. 1 and 2, an optical pickup 100 of the present embodiment has a recording surface (not shown) of each of two recording media 112 and 112 'set at the same time.
It is configured to be able to record and reproduce information with respect to.

For this reason, the optical pickup 100 has a light source (semiconductor laser) 104 capable of emitting recording and reproducing laser light and a laser light emitted from the light source 104 in the direction of the swinging tip of the swing arm 102. A mirror 106 that reflects the light, an imaging lens 110 that regulates the laser light reflected from the mirror 106 into a substantially parallel light beam, and one of the recording media 112 and 112 ′ that outputs the laser light emitted from the imaging lens 110. One galvanomirror 300 that is selectively reflected toward a recording surface (not shown) and that can adjust the beam spot position with respect to the recording surface (tracking control); , 112 ′ are provided with objective lenses 108, 108 ′ for condensing light on the recording surfaces, respectively. Mirror 300 and the objective lens 10
8, 108 'are arranged so as to be optically coincident with the front focal position Ff.

The objective lenses 108 and 108 'are provided at the swinging tip of the swing arm 102, respectively, and are arranged to face the respective recording surfaces of the recording media 112 and 112'.

Further, the optical pickup 10 of the present embodiment
0 is provided with a light guiding optical system 114 for guiding the laser light from the light source 104 to the mirror 106. The light guiding optical system 114 is a collimator for converting the laser light from the light source 104 into a parallel light beam. A lens 116 and a relay lens 118 for condensing the laser beam converted into a parallel light beam by the collimator lens 116 on the mirror 106
And

In this embodiment, the galvanomirror 3
As an example, the laser beam 00 has a reflecting surface formed on one surface thereof, and selectively reflects the laser light guided by the imaging lens 110 toward one of the objective lenses 108 and 108 '. And recording media 112, 112
The rotation is controlled by a drive mechanism (not shown) so that the beam spot position with respect to the recording surface of 'can be adjusted (tracking control). The galvanomirror 300 applied to the present embodiment has, for example, an arrow R
The image forming lens 11 is rotated by 90 ° in the
The laser light from 0 is selectively applied to the objective lenses 108 and 10.
8 ′.

In such an optical pickup 100, the collimator lens 116 and the relay lens 118
, The center of the imaging lens 110 and the objective lens 108, and the center of rotation of the galvanomirror 300 coincide on the same optical axis A.

In the optical path between the collimator lens 116 and the relay lens 118, a galvanomirror 30
The tracking detector 12 capable of optically detecting the tracking state by receiving the return light from 0 (reflected light reflected from the recording surfaces of the recording media 112 and 112 ').
0 is arranged. In the optical path between the mirror 106 and the imaging lens 110, an angle detector 122 that can optically detect the rotation angle of the galvanometer mirror 300 is arranged.

The tracking detector 120 has a beam splitter 124 for reflecting the return light from the galvanometer mirror 300, receives the return light reflected from the beam splitter 124, and generates an electric signal corresponding to a change in the light receiving position, ie, tracking. Light receiving element 126 that outputs a state detection signal
Are provided.

The objective lenses 108 and 108 'are disposed on optical heads 128 and 128' supported on the swinging tip of the swing arm 102, respectively, and swing the swing arm 102 about a rotation shaft 130. Then, by swinging the swinging tip of the swing arm 102 in the direction of arrow S, the objective lenses 108, 108 'of the optical heads 128, 128' are moved in the radial direction of the recording media 112, 112 '. Is available.

According to such a configuration, when the direction of the reflecting surface of the galvanomirror 300 is switched and the laser beam is selectively focused on one of the recording media 112 and 112 ', the swing The arm 102 is swung about a rotation shaft 130 so that the optical heads 128, 128
Is moved along the radial direction of the recording media 112, 112 ', whereby the spot position of the laser beam on one of the recording surfaces of the recording media 112, 112' is coarsely adjusted (coarse tracking control). . At the same time, by slightly moving the galvanomirror 300, the spot position of the laser beam with respect to the recording surface of one of the recording media 112, 112 'is finely adjusted (fine movement tracking control).

While such coarse and fine tracking control is being performed, the laser light emitted from the light source 104 is transmitted from the light guide optical system 114 and the mirror 106 via the imaging lens 110 to the galvano mirror 300. After that, the objective lenses 108, 108 of the optical heads 128, 128 'are selectively passed through the galvanometer mirror 300.
Is focused along the track formed on the recording surface of one of the recording media 112, 112 '. As a result, one of the recording media 11
Optical recording or optical reproduction of information on the 2,112 'recording surface is selectively performed.

According to the present embodiment, the galvanomirror 3
00 by a predetermined angle (specifically, 9
0 °), and in this state, the galvanomirror 3
The laser light is selectively focused on the recording surfaces of the recording media 112, 112 'via one of the objective lenses 108, 108' by only slightly rotating the laser beam 00, and the beam spot position with respect to the recording surface. (Tracking control) can be performed.

Further, since the laser beam from the light source 104 is divided in two directions by the galvanomirror 300, information can be recorded and reproduced using the laser beam from the light source 104 as it is. For this reason, the amount of laser light is not halved as in the conventional case. For example, even when a low-output light source is used, recording and reproducing laser light having a sufficient amount of light is always secured. It becomes possible.

As described above, according to the present embodiment, a low-cost, small-sized device capable of concentrating a sufficient amount of laser light on the recording surfaces of the plurality of recording media 112, 112 'with a simple configuration. Optical pickup 100 can be provided.

Further, a hemispherical lens (for example, an immersion lens) and a magnetic coil are added to the optical heads 128 and 128 ', respectively, and the focused light from the objective lenses 108 and 108' is further narrowed down by the hemispherical lenses to record. The spot diameter of the laser beam focused on the recording surface of the medium (for example, a magneto-optical disk) 112, 112 'is further reduced, and the action between the rotated recording medium 112, 112' and the optical head 128, 128 'is performed. Aerodynamic lift
The optical heads 128, 128 'are connected to the recording media 112, 112.
'May slightly float from the recording surface.
By combining such techniques, the spot diameter of the laser beam can be further reduced without performing focus control, and the recording density on the recording surfaces of the recording media 112 and 112 'can be improved.

The present invention is not limited to the above-described embodiment, but can be variously modified as follows. As a first modified example, for example, FIG.
As shown in (b), reflecting surfaces may be formed on both surfaces of the galvanomirror 300.

According to this modification, the laser beam from the imaging lens 110 is rotated by rotating the galvanometer mirror 300 by 180 ° in the direction of arrow R by the driving mechanism and finely rotating the galvanometer mirror 300 in this state. The beam spot can be selectively reflected toward one of the objective lenses 108 and 108 'and the beam spot position with respect to the recording surface of the recording media 112 and 112' can be adjusted (tracking control).

As a second modification, for example, FIG.
As shown in (a) and (b), a galvanomirror 300 having a parallelepiped shape may be applied, and two first and second reflection surfaces 200 and 202 may be formed on the galvanomirror 300. In this case, the first reflection surface 200 is formed at an inclination angle capable of reflecting the laser light toward the objective lens 108, and the second reflection surface 202 transmits the laser light to the objective lens 108 '. It is formed at an angle of inclination that can be reflected toward.

According to this modification, the galvanomirror 300 is rotated by 60 ° in the direction of arrow R by the drive mechanism so that the first and second reflecting surfaces 200 and 202 are selectively positioned on the optical axis A. The first and second reflecting surfaces 20
The laser beam from the imaging lens 110 is selectively switched by switching the direction of the zoom lens 0 and 202 and slightly rotating the galvanometer mirror 300 in that state.
The beam spot position can be adjusted (tracking control) by reflecting toward either one of the recording media 108 'and the recording surface of the recording media 112, 112'.

Further, as a third modification, for example, FIG.
As shown in (a) and (b), a galvano mirror 300 having two first and second reflecting surfaces 204 and 206 adjacent to each other may be applied. In this case, the first and second
The first laser beam reflected from the reflecting surfaces 204 and 206 of the laser beam toward the objective lenses 108 and 108 ', respectively.
And the second reflection mirrors 208 and 210 are required.

According to this modification, the galvanomirror 300 is rotated in the direction of arrow R by the driving mechanism so that the first and second reflecting surfaces 204 and 206 are selectively positioned on the optical axis A. First and second reflecting surfaces 204, 20
6 is switched and the galvanomirror 30 is switched in that state.
0 is finely rotated. As a result, the laser light emitted from the imaging lens 110 to the first reflection surface 204 is condensed on the recording surface of the recording medium 112 from the first reflection mirror 208 via the objective lens 108, and The beam spot position is adjusted (tracking control).
On the other hand, the second reflecting surface 20
6 is applied to the second reflection mirror 210.
Is focused on the recording surface of the recording medium 112 'via the objective lens 108', and the beam spot position with respect to this recording surface is adjusted (tracking control).

Further, in the above embodiment, an example was described in which the optical pickup 100 having the telecentric optical system was arranged on the swing arm 102. However, the present invention is not limited to this.
And the optical heads 128, 128 'with the recording media 112, 1
The optical system may be configured to be moved in the radial direction of 12 ', and other optical system components may be fixed.

According to this modification, the galvanomirror 30
0 and the optical heads 128, 128 '
By moving along the radial direction of 112 ',
The spot position of the laser beam with respect to one of the recording surfaces of the recording media 112 and 112 'is coarsely adjusted (coarse tracking control), and at the same time, the galvanomirror 300 is finely rotated to thereby make one of the recording media 1
The spot position of the laser beam with respect to the recording surface of 12,12 'is finely adjusted (finely tracking control).

By controlling the rotation of the galvanometer mirror 300 as described in the above embodiment and the first to third modifications together with the coarse movement and fine movement tracking control, the recording media 112 and 112 are controlled. Optical recording or optical reproduction of information on the recording surface of 'is selectively performed.

[0035]

According to the present invention, there is provided a low-cost, small-sized optical pickup capable of concentrating a sufficient amount of laser light on the recording surfaces of a plurality of recording media with a simple structure. Can be.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an optical pickup according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a state where the optical pickup of the present invention is disposed on a swing arm.

FIGS. 3A and 3B are perspective views showing a rotating state of a galvanomirror applied to a first modification of the present invention.

FIGS. 4A and 4B are perspective views showing a rotating state of a galvano mirror applied to a second modification of the present invention.

FIGS. 5A and 5B are perspective views showing a rotating state of a galvanomirror applied to a third modification of the present invention.

[Explanation of symbols]

 Reference Signs List 100 optical pickup 104 light source 112, 112 'recording medium 300 galvanomirror

Claims (2)

[Claims] An optical pickup capable of recording and reproducing information on and from a recording surface of each recording medium by irradiating a plurality of recording media with a laser beam, comprising: a laser beam from a light source; Is selectively reflected toward any one of the plurality of recording media, and is capable of adjusting a beam spot position with respect to a recording surface of each of the recording media.
An optical pickup comprising two galvanometer mirrors. 2. A galvanomirror is provided with a reflecting surface for reflecting a laser beam, and the galvanomirror is turned to switch the direction of the reflecting surface so that laser light from a light source can be selectively emitted. 2. The optical pickup according to claim 1, wherein the light is reflected toward any one of the plurality of recording media, and a beam spot position with respect to a recording surface of each of the recording media is adjusted.