JP3441656B2 - Optical information recording / reproducing device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording / reproducing apparatus, and more particularly to a technique for detecting a deflection amount of a deflecting means in an optical information recording / reproducing apparatus configured to deflect a laser beam to perform fine movement tracking of an optical disk. Is.

[0002]

Recently, the areal recording density is 1
Development of a magneto-optical disk device exceeding 0 Gbit / (inch) ² is in progress. In this device, the incident angle of the laser light flux with respect to the objective optical system provided at the tip of the coarse movement arm that moves (rotates, for example) in the direction intersecting with the track of the magneto-optical disc is finely adjusted by a deflection means such as a galvano mirror. It is considered to make fine adjustments to accurately perform fine movement tracking at a narrow track pitch level of, for example, 0.34 μm. In this case, if the amount of rotation of the galvanometer mirror exceeds a certain range, there is a problem that the optical performance is significantly deteriorated. For this reason, it is necessary to monitor the amount of rotation of the galvanometer mirror and control so as not to exceed a predetermined rotation range.

[0003]

In view of the above background, an optical information recording / reproducing apparatus according to a first aspect of the present invention provides a laser light source for emitting parallel laser beams and a laser beam emitted from the laser light source. An objective lens system for converging on an optical disk, a fine movement tracking device, a coarse movement tracking device, a tracking detection means, and a tracking control means are provided. The fine movement tracking device is a deflection mirror rotatably provided between the laser light source and the objective lens system, and the laser beam incident on the objective lens system is rotated by rotating the deflection mirror. A deflection mirror configured to change the incident angle and the position of the laser beam converged on the optical disc, and at least first and second relay lens groups arranged between the deflection mirror and the objective lens system. A relay lens system that makes the deflection mirror and the entrance pupil of the objective lens system substantially conjugate, and a diffraction grating that is arranged between the laser light source and the deflection mirror. A diffraction grating that separates an incident light beam into at least 0th-order light and ± 1st-order diffracted light having a predetermined diffraction angle, and makes the incident light into the deflection mirror; And a rotation amount detecting means for detecting the amount of rotation of the deflection mirror by receiving the reflected ± 1-order diffracted light by the polarizing mirror. The coarse movement tracking device is provided with the objective lens system and includes a rotating arm that is rotatable in a direction parallel to the recording surface of the optical disc. In the above configuration, the tracking detection means generates a tracking error signal by receiving the reflected light from the optical disc, and the control means generates the tracking error signal generated by the tracking detection means and the tracking error signal. Based on the rotation amount of the deflection mirror detected by the movement amount detecting means, the rotation position of the deflection mirror after fine movement tracking is obtained, and if the rotation position is within a predetermined range, the fine movement tracking device is driven. When the rotation position exceeds a predetermined range, the coarse movement tracking device is driven to perform tracking.

In the optical information recording / reproducing apparatus according to a second aspect, only the 0th-order diffracted light reflected by the polarization mirror is transmitted toward the objective lens system, and the ± 1st-order diffracted light is incident on the objective lens system. It is characterized by having a light shielding means for preventing

Further, in the optical information recording / reproducing apparatus according to the third aspect, the detecting means detects the rotation amount of the deflection mirror based on the light amount of the ± first-order diffracted light reflected by the deflection mirror. Is characterized by.

Further, in the optical information recording / reproducing apparatus according to the fourth aspect, the detecting means are arranged in a direction orthogonal to the rotation axis of the deflecting mirror and receive at least a part of the ± first-order diffracted light. It is characterized in that it has at least two light receiving regions, and detects the turning position of the deflection mirror based on the difference in the amount of the ± first-order diffracted light received by the two light receiving regions.

On the other hand, in the optical information recording / reproducing apparatus according to a fifth aspect of the present invention, the detecting means rotates the deflecting mirror based on the incident position of the ± first-order diffracted light reflected by the deflecting mirror with respect to the detecting means. It is characterized by detecting the amount of motion.

According to a sixth aspect of the optical information recording / reproducing apparatus, the diffraction grating has a plurality of linear grooves extending in a direction parallel to the rotation axis of the deflecting mirror, and the detecting means includes: There are two light receiving regions that are arranged in a direction orthogonal to the rotation axis of the deflection mirror and that respectively receive at least a part of the ± 1st order diffracted light, and the ± 1 next time received by the two light receiving regions is included. It is characterized in that the turning position of the deflection mirror is detected based on the difference in the amount of the folded light.

An optical information recording / reproducing apparatus according to a thirteenth aspect is
The diffraction grating has a plurality of linear grooves extending in a direction orthogonal to the rotation axis of the deflection mirror, and the detection means,
Arranged in a direction orthogonal to the rotation axis of the deflection mirror,
The first and second light receiving regions that receive at least a part of the + 1st order diffracted light of the ± 1st order diffracted light and the ± 1st order diffracted light are arranged in the direction orthogonal to the rotation axis of the deflection mirror. A plate member provided with third and fourth light receiving regions for receiving at least a part of the minus first-order diffracted light, and the light amount of the light received by the first and third light receiving regions and the above The turning position of the deflection mirror is detected based on the difference between the light amounts of the light received by the second and fourth light receiving regions.

In the optical information recording / reproducing apparatus according to the sixteenth aspect, the diffraction grating has a plurality of linear grooves extending in a direction orthogonal to the rotation axis of the deflection mirror, and the detection means is the first A plate member provided between the first and second relay lens groups, the plate member having at least one position detection element extending in a direction orthogonal to the rotation axis of the deflection mirror; + 1st order diffracted light or -1
At least a part of the order diffracted light is configured to be converged on the position detection element, and the detection means is based on a position of at least a part of the + 1st order diffracted light or the −1st order diffracted light on the position detection element. The feature is that the turning position of the deflection mirror is detected.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. First, near field recording (NFR: near field recording) was proposed in response to the increasing demand for external storage devices, especially for large storage capacities, as hardware and software have advanced in recent years.
The outline of a magneto-optical disk recording / reproducing apparatus using a recording / reproducing system called “rding” technology will be described with reference to FIGS.

FIG. 1 is an overall schematic diagram of the optical disk device. An optical disk 2 is mounted on the rotary shaft of a spindle motor (not shown) in the disk drive device 1. On the other hand, in order to reproduce or record information on the optical disc 2, a rotating (coarse movement) arm 3 is attached so as to be parallel to the recording surface of the optical disc 2. This rotating arm 3
Is rotatable by a voice coil motor 4 about a rotary shaft 5. A floating optical head 6 having an optical element is mounted on the tip of the rotating arm 3 facing the optical disk 2. Also, the rotating arm 3
A light source module 7 including a light source unit and a light receiving unit is disposed in the vicinity of the rotating shaft 5 and is configured to be driven integrally with the rotating arm 3.

FIGS. 2 and 3 explain the tip of the rotary arm 3, and particularly the floating optical head 6 in detail. The floating optical unit 6 is attached to the flexure beam 8 and is arranged so as to face the optical disc 2. Further, the flexure beam 8 is fixed to the rotating arm 3 at the other end, and the elastic force of the flexure beam 8 presses the levitation optical unit 6 at the tip end in a direction of contacting the optical disc 2.

The levitation type optical unit 6 comprises a levitation slider 9, an objective lens 10 and a solid immersion lens (S).
IL) 11 and a magnetic coil 12, and serves to converge the parallel laser light flux 13 emitted from the light source module 7 onto the optical disc 2. A rising mirror 31 is fixed to the tip of the rotating arm 3 for guiding the laser beam 13 to the floating optical unit 6. Objective lens 1 by the raising mirror 31
The laser light flux 13 incident on 0 is converged by the refraction of the objective lens 10. The solid immersion lens (SIL) 11 is a hemispherical lens, the flat surface of which is arranged so as to oppose the light disk 2. The solid immersion lens (SIL) 11 is arranged so that the focal point of the objective lens 10 is located on a substantially flat surface, and irradiates the optical disc 2 with the convergent light from the objective lens 10 as a finer evanescent light 15.

A magnetic coil 12 for recording by the magneto-optical recording system is formed around the solid immersion lens (SIL) 11 facing the optical disc 2, and a magnetic field required for recording is recorded on the optical disc 2. It can be applied on the surface. This evanescent light 1
5 and the magnetic coil 12 enable high-density recording and reproduction on the optical disc 2. The levitation type optical unit 6 is a unit that levitates a minute amount (about 1 μm) by the air flow caused by the rotation of the optical disc 2, and follows the surface wobbling of the optical disc 2. For this reason, the focus control (focus servo) of the objective lens that was necessary in the conventional optical disk device
However, this is not required in the optical disk device 1.

The light beam guided to the light source module 7 mounted on the rotating arm 3 and the floating optical unit 6 will be described in detail below with reference to FIGS. 4 and 5. FIG. 4 is a top view of the rotating arm 3, and FIG. 5 is a sectional view. The rotary arm 3 has a floating optical unit 6 mounted at its tip, and a drive coil 16 for driving the voice coil motor 4 is fixed to the other end. The drive coil 16 is a flat coil, and is inserted and arranged in a magnetic circuit (not shown) with a gap. The rotating shaft 5 and the rotating arm 3 have a bearing 1
It is rotatably fastened by 7 and 17, and when a current is applied to the drive coil, the rotating arm 3 can be rotated about the rotating shaft 5 by the electromagnetic action with the magnetic circuit.

The light source module 7 mounted on the rotating arm 3 includes a semiconductor laser 18, a laser drive circuit 19,
Collimating lens 20, compound prism assay 21, laser power monitor sensor 22, reflecting prism 2
3, a data detection sensor 24, and a tracking detection sensor 25 are arranged. The laser light flux in a divergent light flux state emitted from the semiconductor laser 18 is converted into a parallel light flux by the collimator lens 20. Due to the characteristics of the semiconductor laser 18, the cross-sectional shape of this parallel light flux is elliptical, and it is inconvenient to minutely narrow the light beam onto the optical disc 2, so it is necessary to convert it into a substantially circular cross section. Therefore, the cross-sectional shape of the parallel light flux is shaped by causing the parallel light flux having an elliptical cross-section emitted from the collimator lens 20 to enter the composite prism assay 21.

Incident surface 21a of the composite prism assay 21
Has a predetermined slope with respect to the incident optical axis, and by refracting the incident light, the cross-sectional shape of the parallel light flux can be shaped from an elliptical shape to a substantially circular shape. The shaped laser beam advances through the complex prism assay 21 and is incident on the first half mirror surface 21b. The first half mirror surface 21b uses the information obtained from the optical disc 2 to detect data and the tracking detection sensor 25.
However, it serves to separate the light flux to the laser power monitor sensor 22 for detecting the output power of the laser emitted from the semiconductor laser 18 in the outward path.

Since the laser power monitor sensor 22 outputs a current proportional to the intensity of the received light, the output of the semiconductor laser 18 can be stabilized by feeding back this output to a laser power control circuit (not shown). .

The laser light flux 13 having a substantially circular cross-sectional shape emitted from the composite prism assay 21 is applied to the deflection mirror 26, and the traveling direction of the laser light flux 13 is changed.

Tracking consists of two steps: coarse movement tracking performed by rotating the rotating arm 3 and fine movement tracking performed by rotating the deflection mirror 26. The access operation across the inner circumference / outer circumference of the optical disk 2 is performed by rotating the rotating arm 3 by the voice coil motor 4 (coarse tracking), and only the minute tracking control is rotated by rotating the deflection mirror 26 ( Fine tracking).

The deflection mirror 26 is attached to a galvanomotor 27 whose center of rotation is an axis perpendicular to the paper surface of FIG. 4 so that the laser beam 13 can be swung by a minute angle in a direction parallel to the paper surface of FIG. It has become.

The laser beam 13 reflected by the deflecting mirror 26 passes through the first relay lens 29 and the second relay lens (imaging lens) 30, and is reflected by the rising mirror 31 to reach the levitation type optical unit 6. This first
The relay lens 29 and the second relay lens 30 of
The reflecting surface of the deflecting mirror 26 and the pupil plane (main plane) of the objective lens 10 arranged in the levitation type optical unit 6 are made to have a conjugate relationship, and form a relay lens optical system. is there. That is, when the condensed beam on the optical disc 2 is slightly deviated from the predetermined track, the objective lens 10 is rotated by slightly rotating the deflection mirror 26.
The laser beam 13 incident on is tilted to move the spot on the optical disc 2 for correction.

However, when the spot position is corrected (that is, fine movement tracking) by this method, if the optical distance between the deflection mirror 26 and the objective lens 10 is long,
In some cases, the amount of movement of the laser light flux 13 incident on the objective lens 10 becomes large and the laser light flux 13 cannot be incident on the objective lens 10.

In order to avoid such a problem, the first relay lens 29 and the second relay lens 30 are set so that the vicinity of the reflecting surface of the deflecting mirror 26 and the pupil plane of the objective lens 10 have a conjugate relationship. However, even if the deflection mirror 26 rotates, the laser light flux 13 that enters the objective lens 10
The position of is not moved and only the incident angle is changed so that accurate tracking control is possible.

The returning laser beam 13 reflected from the optical disk 2 travels in the reverse direction of the outward path and is deflected by the deflection mirror 2.
It is reflected by 6 and enters the composite prism assay 21.
After that, the light is reflected by the first half mirror surface 21b and heads for the second half mirror surface 21c. The second half mirror surface 21c generates a transmitted light toward the tracking detection sensor 25 and a reflected light toward the data detection sensor 24, and separates the return laser light flux. The laser light flux that has passed through the second half mirror surface 21c is applied to the tracking detection sensor 25 and outputs a tracking error signal.

On the other hand, the laser light flux reflected by the second half mirror surface 21c is polarized and separated by the Wollaston prism 32, converted into convergent light by the condenser lens 33, and then reflected by the reflection prism 23 to be detected by the data detecting sensor. 24 is irradiated. The data detection sensor 24 has two light receiving regions, and receives the two polarized beams that are polarized and separated by the Wollaston prism 32 to read the data information recorded on the optical disc 2 and output a data signal. To be precise, the tracking error signal and the data signal are generated by a head amplifier circuit (not shown) and sent to the control circuit or the information processing circuit.

An embodiment of an optical system for detecting the rotation amount of the deflection mirror 26, which is applicable to the above optical information recording / reproducing apparatus, will be described below.

FIG. 6 is an optical layout diagram showing the configuration of an optical system 1000 applicable to the above-mentioned disk drive device 1, and is a diagram when the light beam is on the optical axis of the design center. As described above, the parallel light flux emitted from the light source module 7 is applied to the deflection mirror 26 and its traveling direction is deflected. The deflecting mirror 26 has a surface coated with a reflection coat, and has a structure capable of rotating about a rotation axis O1 within a predetermined range. This turning operation is performed by the galvano motor 27, and the deflection mirror 26 has a so-called galvano mirror configuration. The parallel light flux 1 reflected by the deflecting mirror 26 enters the first relay lens 29 and becomes convergent light.

The first relay lens 29 and the second relay lens 30 are arranged so that the rear focal point of the first relay lens 26 and the front focal point of the second relay lens 30 coincide with each other, and the deflection is performed. Center of rotation of mirror 26 (rotation axis O1)
The relay lens system is set so that the relationship between the main plane of the objective lens 10 (the position of the entrance pupil) is a so-called conjugate relationship. Therefore, even if the deflected mirror 26 rotates and the reflected parallel light beam is inclined, the incident position of the parallel light beam entering the objective lens 10 does not shift, and only the incident angle changes, and the incident light to the objective lens 10 changes. It has a structure that can prevent vignetting.

The light flux that has exited the second relay lens 30 and has returned to the parallel light flux is reflected by the rising mirror 31 and enters the objective lens 10. A hemispherical solid immersion lens (SIL) 11 is provided near the focal point of the objective lens 10.
Is arranged, and functions to irradiate the optical disc 2 with the light flux converged by the objective lens 10 as finer evanescent light.

The optical system 1000 has the following configuration in order to detect the rotation amount of the polarization mirror 26. As shown in FIG. 6, the diffraction grating 50 is arranged in the parallel light flux 111 between the deflection mirror 26 and the light source module 7, and the parallel light flux 111 is transmitted. The diffraction grating 50 is a transmissive optical element having a rectangular cross section, and is arranged so that the direction of the linear grating is parallel to the rotation axis O1 of the polarization plane, and the incident parallel light flux 111 goes straight as it is. The light and the ± first-order light traveling with a predetermined separation angle are separated. The light quantity ratio and separation angle of the 0th order light and the ± 1st order light can be changed depending on the depth and pitch of the grating. In addition, in order to show a direction, the XYZ orthogonal coordinate axis was shown in FIG. The linear lattice direction is the Z direction.

The arrangement direction of the diffraction grating 50 is the direction shown in FIG. 7, and the ± first-order light is separated in the plane in which the parallel light flux is deflected by the deflection mirror 26. In addition, in order to show a direction, the XYZ orthogonal coordinate axis was also shown in FIG. The ± first-order lights 111a and 111b reflected by the deflection mirror 26
Are light receiving parts 40a, 40 of the photodetector 40.
b, and the remaining part is the window 40H of the photodetector 40.
Through.

The photodetector 40 is composed of a plate member, and as shown in FIG. 8, light receiving elements 40a and 40b for receiving the ± first-order lights 111a and 111b and detecting the amount of received light are formed. The deflection mirror 26 is rotated to move the light receiving element 4
When the positions of the ± first-order lights 111a and 111b with respect to 0a and 40b are moved, there is a difference in the amount of light emitted to the light receiving elements 40a and 40b. Therefore, the light receiving elements 40a, 40b
It is possible to detect the position of the parallel light flux 111 deflected by the differential output of. That is, the rotation amount of the polarization mirror 26 can be detected. A part of the ± first-order light that has passed through the window 40H of the photodetector 40 is incident on the first relay lens 29 and converges in the vicinity of the focus of the first relay lens 29.

± transmitted through the first relay lens 29
The primary lights 111c and 111d are transmitted through the first relay lens 29.
Since it is obliquely incident on, the convergence position is shifted in the vertical direction (X direction) in FIG. The ± first-order lights 111c and 111d are lights that are unnecessary for recording / reproducing on / from the optical disc 2, and if they are incident on the objective lens 10, a problem occurs. Therefore, approximately the centers of the first relay lens 29 and the second relay lens 30 are included. A spatial filter 45 having an aperture 45H as shown in FIG.
It is designed to block light. As a result, the required luminous flux (0
Only the next light passes through the aperture 45H and travels toward the objective lens 10, and unnecessary light beams are cut.

The deflection mirror 26 is shown in FIGS.
FIG. 6 is a diagram showing a positional change of a light beam when is rotated by θ. The parallel light beam 111 with respect to the rotation angle θ of the deflection mirror 26
Has a reflection angle of 2θ, and the luminous flux is the first relay lens 29.
Is obliquely incident on. Therefore, the convergence point of the light flux by the relay lens system formed by the first relay lens 29 and the second relay lens 30 moves in the direction parallel to the paper surface of FIG. 10 (direction parallel to the XY plane). It will be.

At this time, ± 1 reflected by the deflection mirror 26
The secondary lights 111a and 111b move by the rotation of the deflection mirror 26, and the position irradiated on the photodetector 40 changes.
The light receiving elements 40a and 40b of the photodetector 40 are set so that the ± first-order lights 111a and 111b strike the light receiving elements 40a and 40b in equal amounts when the deflection mirror 26 is located at the reference position shown in FIG. If it says, ± 1st order light 111a, 11
Since the output of the light receiving elements 40a and 40b is different due to the movement of 1b, it is possible to know the change of the traveling direction (deflection direction) of the light beam with respect to the reference optical axis shown in FIG. It becomes possible to detect a corner. Also in this case, the ± first-order lights 111c and 111d transmitted through the window 40H of the photodetector 40 are removed by the spatial filter 45 as shown in FIG. 12, and only the 0th-order light enters the objective lens 10. It is like this.

FIG. 13 is a block diagram of the tracking control system. The tracking control system controls the fine movement tracking of the rotating arm 3 and the deflection mirror 26. The output signals of the light receiving units 40a and 40b are input to the differential amplifier 160. The output signal of the differential amplifier 160 is input to the CPU 150. The CPU 150 uses the signal from the differential amplifier 160 to determine the current deflection mirror 2
The rotation position of 6 is detected.

When performing fine movement tracking, the CPU 150
Calculates how much the deflecting mirror 26 is further rotated from the present rotating position of the deflecting mirror 26 based on the output of the tracking detection sensor, and obtains the rotating position of the deflecting mirror 26 after performing the fine movement tracking. . If,
If the turning position of the deflection mirror 26 after the fine movement tracking is within a predetermined turning range, the CPU 150 controls the driver 127 to drive the galvano motor 27,
The deflection mirror 26 is rotated to perform fine movement tracking.

If the turning position of the deflection mirror 26 after the fine movement tracking exceeds the position within the predetermined turning range, the CPU 150 does not perform the fine movement tracking by the deflection mirror 26, and the calculated deflection mirror 26. The rotation position of is converted into the movement position of the rotation arm 3. And C
The PU 150 controls the driver 116 to drive the drive coil 1
By driving 6 to rotate the rotating arm 3, tracking is performed not by the deflection mirror 26 but by the rotating arm 3. By this control, the deflection mirror 26 can be prevented from rotating beyond a predetermined range, and deterioration of optical performance can be suppressed. If necessary, it is possible to further perform fine movement tracking by the deflecting mirror 26 after this.

With the above structure, the incident angle of the laser beam with respect to the objective optical system provided at the tip of the coarse movement arm that moves in the direction intersecting the track of the magneto-optical disk is finely adjusted by the deflecting means such as a galvano mirror. In an optical information recording / reproducing apparatus that accurately performs fine movement tracking, it is possible to accurately detect the amount of rotation of the deflection mirror, and therefore it is possible to perform accurate tracking without deteriorating the optical performance of the apparatus.

FIG. 14 is an optical layout diagram showing the structure of an optical system 2000 which can be applied to the above-mentioned disk drive device 1 and which can detect the rotation amount of the polarization mirror 26. The light beam is on the optical axis of the design center. It is a figure of a case. In addition, FIG.
FIG. 15 is a side sectional view when the optical system 2000 is viewed from the X-axis direction of the XYZ orthogonal coordinate system shown in FIG. 14. The parallel light flux emitted from the light source module 7 is reflected by the deflection mirror 26, enters the first relay lens 29, and becomes convergent light.

The first relay lens 29 and the second relay lens 30 are arranged so that the rear focal point of the first relay lens 26 and the front focal point of the second relay lens 30 coincide with each other, and the deflection is performed. Center of rotation of mirror 26 (rotation axis O1)
The relay lens system is set so that the relationship between the main plane of the objective lens 10 (the position of the entrance pupil) is substantially conjugate. Therefore, even if the deflecting mirror 26 rotates from the reference position shown in FIG. 14 and the parallel light flux reflected by the deflecting mirror 26 tilts with respect to the optical axis, the incident position of the parallel light flux entering the objective lens 10 is Only the incident angle is changed without shifting, and the vignetting of the incident light on the objective lens 10 can be prevented.

As shown in FIG. 15, the light flux that has exited the second relay lens 30 and has returned to the parallel light flux is directed to the rising mirror 3.
It is reflected by 1 and enters the objective lens 10. A hemispherical solid immersion lens (SIL) 11 is arranged in the vicinity of the converging point of the objective lens 10, and the objective lens 1
The optical flux converged by 0 is applied to the optical disc 2 as finer evanescent light.

In the optical system 2000 having the above structure, the diffraction grating 150 is arranged in the parallel light beam between the deflection mirror 26 and the light source module 7. The diffraction grating 150 is a transmissive optical element having a rectangular cross section, and is arranged so that the linear grating direction is orthogonal to the rotation axis of the polarization plane (extends in the Y-axis direction). The parallel light flux incident on the diffraction grating 150 is split into a 0th-order light that travels straight as it is and a ± 1st-order light having a predetermined separation angle. The light quantity ratio and separation angle of the 0th order light and the ± 1st order light can be changed depending on the depth and pitch of the grating.

The diffraction grating 150 separates the ± first-order light in the direction orthogonal to the plane (XY plane) on which the parallel light beam is deflected by the deflection mirror 26. That is, the linear grating direction of the diffraction grating 150 is the Y direction in the figure, and the ± first-order diffracted lights 111a and 111b are separated in the Z direction in the figure. The ± first-order lights 111a and 11 reflected by the deflection mirror 26
1b is a part of the light receiving element 14 of the photodetector 140.
0a and 140b, light receiving elements 140c and 140d
To the photodetector 140, and the remaining part is irradiated with the 0th-order light.
Through the window 140H.

The photodetector 140 is composed of a plate member, and as shown in FIG.
Light receiving elements 140a and 140b and light receiving elements 140c and 14 that receive b and output a signal corresponding to the amount of received light.
0d are formed so as to sandwich the opening 140H. When the deflection mirror 26 rotates, the light receiving elements 140a to 140d
The positions of the ± first-order lights 111a and 111b incident on the X-direction are moved in the X direction, and the difference between the sum of the amounts of light emitted to the light receiving elements 140a and 140c and the sum of the amounts of light emitted to the light receiving elements 140b and 140d is Therefore, the position of the parallel light flux 111 can be detected by the differential output. If the electric signal from the light receiving element is represented by the number of the light receiving element, the position of the parallel light flux 111 with respect to the photodetector 140 can be detected by (140a + 140c)-(140b + 140d). That is, the rotation amount of the polarization mirror 26 can be detected. Photo detector 140
Part of the ± first-order light that has passed through the window 140H enters the first relay lens 29 and converges in the vicinity of the focal point of the first relay lens 29.

± transmitted through the first relay lens 29
The primary lights 111c and 111d are transmitted through the first relay lens 29.
Since it is obliquely incident on, the convergence position is shifted in the vertical direction (X direction) in FIG. ± 1st order light 111c, 111d
Is unnecessary light for recording / reproducing on / from the optical disc 2, and a problem occurs when it is made incident on the objective lens 10. Therefore, as shown in FIG. 17, approximately in the center of the first relay lens 29 and the second relay lens 30. With a spatial filter 145 having a large aperture 145H,
1d is shielded from light. As a result, only the necessary light flux (0th order light) passes through the aperture 145H and travels toward the objective lens 10, and the unnecessary light flux is cut.

Deflection mirror 26 is shown in FIGS.
Is a diagram showing a position change of the light flux when is rotated by θ, and corresponds to FIGS. 14, 16 and 17, respectively. The reflection angle of the parallel light beam 111 is 2θ with respect to the rotation angle θ of the deflection mirror 26, and the light beam obliquely enters the first relay lens 29. Therefore, the convergence point of the light flux by the relay lens system formed by the first relay lens 29 and the second relay lens 30 is in the direction parallel to the paper surface of FIG. 18 (X direction).
Will be moved in.

At this time, ± 1 reflected by the deflection mirror 26
The secondary lights 111a and 111b move due to the rotation of the deflection mirror 26, and the position irradiated on the photodetector 140 changes. When the polarization mirror 26 is located at the reference position as shown in FIG. 14, the sum of the amounts of the ± first-order lights 111a and 111b applied to the light receiving elements 140a and 140c and the amount of the light applied to the light receiving elements 140b and 140d. If the sum is set to have the same light quantity, the sum of the signal outputs of the light receiving elements 140a and 140c and the sum of the signal output of the light receiving elements 140b and 140d are different due to the movement of the ± first-order lights 111a and 111b. Therefore, it is possible to know the change of the light flux from the reference optical axis shown in FIG. 14, and it is possible to detect the rotation angle of the deflecting mirror 26 proportional thereto. Also in this case, the ± first-order light 111 transmitted through the window 140H of the photodetector 140
c and 111d are spatial filters 4 as shown in FIG.
Only the 0th-order light is incident on the objective lens 10 after being removed by 5.

FIG. 21 is a block diagram of a tracking control system used together with the optical system 2000. The tracking control system controls the fine movement tracking of the rotating arm 3 and the deflection mirror 26. Light receiving element 1
The output signals of 40a and 140b are added by adder 170A, and the output signals of light receiving elements 140c and 140d are added by adder 170B. 170A adder
The output signals of 170 and 170B are input to the differential amplifier 160, and the output signal of the differential amplifier 160 is input to the CPU 150. The CPU 150 detects the current rotation position of the deflection mirror 26 based on the signal from the differential amplifier 160.

When performing fine tracking, the CPU 150
Calculates how much the deflecting mirror 26 is further rotated from the present rotating position of the deflecting mirror 26 based on the output of the tracking detection sensor, and obtains the rotating position of the deflecting mirror 26 after performing the fine movement tracking. . If,
If the turning position of the deflecting mirror 26 after the fine movement tracking is within a predetermined turning range, the CPU 150 controls the driver 127 to drive the galvanometer mirror 27 and turn the deflecting mirror 26 to make a fine movement. Perform tracking.

If the turning position of the deflection mirror 26 after the fine movement tracking exceeds the position within the predetermined turning range, the CPU 150 does not perform the fine movement tracking by the deflection mirror 26, and the calculated deflection mirror 26. The rotation position of is converted into the movement position of the rotation arm 3. And C
The PU 150 controls the driver 116 to drive the drive coil 1
By driving 6 to rotate the rotating arm 3, tracking is performed not by the deflection mirror 26 but by the rotating arm 3. By this control, the deflection mirror 26 can be prevented from rotating beyond a predetermined range, and deterioration of optical performance can be suppressed. If necessary, it is possible to further perform fine movement tracking by the deflecting mirror 26 after this.

With the above structure, the incident angle of the laser beam with respect to the objective optical system provided at the tip of the coarse movement arm that moves in the direction intersecting the track of the magneto-optical disk is finely adjusted by the deflecting means such as a galvanometer mirror. In the optical information recording / reproducing head that accurately performs fine movement tracking, it is possible to accurately detect the amount of mirror rotation of the deflection mirror, and thus it is possible to perform fine movement tracking accurately without degrading optical performance.

FIG. 22 is an optical layout diagram of an optical system 3000 which is applicable to the above-mentioned disk drive device 1 and has a configuration for detecting the rotation amount of the polarization mirror 26. In the case where the light beam is on the optical axis of the design center. FIG. The parallel light flux emitted from the light source module 7 is reflected by the deflection mirror 26 and enters the first relay lens 29.

The first relay lens 29 and the second relay lens 30 are arranged so that the rear focal point of the first relay lens 26 and the front focal point of the second relay lens 30 coincide with each other, and the deflection is performed. Center of rotation of mirror 26 (rotation axis O1)
The relay lens system is set so that the relationship between the main plane of the objective lens 10 (the position of the entrance pupil) is a so-called conjugate relationship. Therefore, even if the deflected mirror 26 rotates and the reflected parallel light beam is inclined, the incident position of the parallel light beam entering the objective lens 10 does not shift, and only the incident angle changes, and the incident light to the objective lens 10 changes. It has a structure that can prevent vignetting.

The light flux that has exited the second relay lens 30 and has returned to the parallel light flux is reflected by the rising mirror 31 and enters the objective lens 10. A hemispherical solid immersion lens (SIL) 11 is provided near the focal point of the objective lens 10.
Are arranged and irradiate the optical disc 2 with the light flux converged by the objective lens 10 as finer evanescent light.

The structure for detecting the rotation amount of the polarization mirror 26 in the optical system 3000 having the above structure is as follows. As shown in FIG. 22, the diffraction grating 50 is arranged in the parallel light flux between the deflection mirror 26 and the light source module 7. The diffraction grating 50 is a transmissive optical element having a rectangular cross section, and is arranged so that the linear grating direction is parallel to the rotation axis O1 of the polarization plane (in the Z direction), and the incident parallel light flux travels straight. The light is separated into 0th-order light and ± 1st-order light having a predetermined separation angle. The light quantity ratio and separation angle of the 0th order light and the ± 1st order light can be changed depending on the depth and pitch of the grating.

The linear grating direction of the diffraction grating 50 is the Z direction, and separates the ± first-order light in the plane in which the parallel light flux is deflected by the deflection mirror 26 (in the plane parallel to the XY plane). ± first-order light 111 reflected by the deflection mirror 26
Part of each of a and 111b is applied to the light shielding portion of the aperture limiting plate 245. In the aperture limiting plate 245, when the deflecting mirror 26 is at the reference position shown in FIG. 22, an aperture 245H is formed so as to transmit approximately half of each of the ± first-order lights 111a and 111b as shown in FIG. ing.
A part of each of the ± first-order lights emitted to the aperture limiting plate 245 is shielded, passes through the opening 245H as the ± first-order lights 111c and 111d, and enters the first relay lens 29. The ± first-order lights 111c and 111d that have passed through the first relay lens 29 are obliquely incident on the first relay lens 29, so that their converged positions are displaced in the vertical direction (X direction) in FIG.

The ± first-order lights 111c and 111d transmitted through the first relay lens 29 enter the photodetector 240.
The photodetector 240 is composed of a plate member, and
As shown in, an aperture 240H is formed in the center, and ± 1st order light 1 is formed on both sides of the aperture 240H.
Light receiving elements 240a and 240b are provided which respectively receive the light beams 11c and 111d and output signals corresponding to the received light amount.

The polarization mirror 26 rotates to rotate the ± first-order lights 111.
When a and 111b move in the X direction, a light amount difference occurs between the ± first-order lights 111c and 111d passing through the opening 245H. Since the ± first-order lights 111c and 111d having the light amount difference are incident on the light receiving elements 240a and 240b, the light receiving element 240
It is possible to detect the position of the deflected parallel light beam, and thus the rotational position of the polarization mirror 26, based on the difference between the outputs of a and 240b.

25, 26, and 27 are deflection mirrors 26.
FIG. 6 is a diagram showing a positional change of a light beam when is rotated by θ. The parallel light beam 111 with respect to the rotation angle θ of the deflection mirror 26
Has a reflection angle of 2θ, and the luminous flux is the first relay lens 29.
Is obliquely incident on. Therefore, the convergence point of the light flux by the relay lens system formed by the first relay lens 29 and the second relay lens 30 moves in the direction parallel to the paper surface of FIG. 25 (direction parallel to the XY plane). It will be.

At this time, ± 1 reflected by the deflection mirror 26
The secondary lights 111a and 111b also move by the rotation of the deflection mirror 26, and a light amount difference occurs between the ± first-order lights 111c and 111d passing through the opening 245H of the aperture limiting plate 245. Figure 2
If the ± first-order lights 111c and 111d are set so as to strike the light-receiving elements 240a and 240b at the reference positions of 2, the ± first-order lights 111a and 111b are moved by ±.
Due to the difference in the light amounts of the primary lights 111c and 111d, the light receiving element 24
Since there is a difference between the signal outputs of 0a and 240b, it is possible to know the change of the light flux from the reference optical axis shown in FIG. 22, and therefore it is possible to detect the rotation angle of the deflection mirror 26 based on it. . The window 240 of the photodetector 240
Only the 0th-order light that has passed through H enters the objective lens 10.

For the above optical system 3000, the optical system 1
Since a tracking control system similar to that used with 000 can be used, description thereof will be omitted here.

With the above arrangement, the mirror rotation amount of the deflecting mirror 26 can be accurately detected, so that the fine movement tracking can be accurately performed without deteriorating the optical performance.

FIG. 28 is an optical layout diagram of an optical system 4000 applicable to the disk drive device 1 and configured to detect the rotation amount of the polarization mirror 26. The light beam is on the optical axis of the design center. It is a figure of a case. Further, FIG. 29 is a sectional view taken along the X direction in FIG. The parallel light flux emitted from the light source module 7 is reflected by the deflection mirror 26 and enters the first relay lens 29.

The first relay lens 29 and the second relay lens 30 are the center of rotation of the deflection mirror 26 (rotation axis O1).
The relay lens system is set so that the relationship between the main plane of the objective lens 10 (the position of the entrance pupil) is a so-called conjugate relationship. Therefore, even if the deflected mirror 26 rotates and the reflected parallel light beam is tilted, the incident position of the parallel light beam entering the objective lens 10 does not change, and only the incident angle changes. Vignetting can be prevented.

The light flux which has exited the second relay lens 30 and has returned to the parallel light flux is reflected by the rising mirror 31,
Objective lens 10 and solid immersion lens (S
The optical disc 2 is irradiated with evanescent light via the (IL) 11.

The optical system 4000 having the above structure has the following structure for detecting the amount of rotation of the polarization mirror 26. As shown in FIG. 28, the diffraction grating 150 is arranged in the parallel light flux between the deflection mirror 26 and the light source module 7, and the parallel light flux 111 is transmitted. Diffraction grating 150
Is a transmissive optical element having a rectangular cross section, and is arranged so that the linear grating direction is orthogonal to the rotation axis O1 of the polarization plane (Y direction), and the incident parallel light beam goes straight in the Z direction. The secondary light can be separated into ± first-order light having a predetermined separation angle. The light quantity ratio and separation angle of the 0th order light and the ± 1st order light can be changed depending on the depth and pitch of the grating.

The arrangement direction of the diffraction grating 50 is the Y-axis direction, and the ± first-order lights are separated in the direction (Z direction) orthogonal to the plane on which the parallel light flux is deflected by the deflection mirror 26. ± 1st order light 111a, 1a reflected by the deflection mirror 26
11b is applied to the aperture limiting plate 345, and the remaining part is applied to the photodetector 40 as ± first-order lights 111c and 111d. The aperture limiting plate 345 has a light-shielding portion that cuts unnecessary light that is not necessary for detecting the amount of rotation of the deflection mirror 26, and an opening 345H that allows the 0th-order light and the ± 1st-order light (at least a part thereof) to pass through. Has been done. Opening 345H
The ± first-order lights 111c and 111d that have passed through enter the first relay lens 29. The ± first-order lights 111c and 111d that have passed through the first relay lens 29 are obliquely incident on the first relay lens 29, so that the convergence position of the light flux is as shown in FIG.
In the vertical direction (Z direction). This ± 1st order light 1
11c and 111d are received by the photodetector 340.

As shown in FIG. 31, the photodetector 340 is provided with an aperture 340H in the center and two one-dimensional position detecting elements (PSD) 340a and 340b in the vertical direction in FIG. 31 with the aperture 340H interposed therebetween. It is designed to receive the ± first-order lights 111c and 111d, respectively. The deflection mirror 26 rotates to rotate the ± 1st order light 1.
When 11a and 111b move, the convergence points of the ± first-order lights 111c and 111d that pass through the opening 345H and are irradiated onto the light receiving elements 340a and 340b also move in the X direction, so that the one-dimensional position detection element 340a ± 1 to 340b
The incident positions of the secondary lights 111c and 111d change. The position of the parallel light flux, that is, the turning position of the deflection mirror 26 can be detected by the change of the incident position.

The deflecting mirror 26 is shown in FIGS.
FIG. 6 is a diagram showing a change in position of a light beam when is rotated by θ. The reflection angle of the parallel light beam is 2θ with respect to the rotation angle θ of the deflection mirror 26, and the light beam obliquely enters the first relay lens 29. Therefore, the converging point of the light flux by the relay lens system formed by the first relay lens 29 and the second relay lens 30 moves in the direction parallel to the paper surface of FIG. At this time, the ± first-order lights 111a and 111b reflected by the deflection mirror 26 move by the rotation of the deflection mirror 26, pass through the opening 345H of the aperture limiting plate 345, and
The primary lights 111c and 111d are emitted to the photodetector 340. The one-dimensional position detection elements 340a for the ± first-order lights 111c and 111d set at the reference position in FIG.
With reference to the position on 340b, ± first-order lights 111a, 1
Since the incident positions of the ± first-order lights 111c and 111d are changed by the movement of 11b, it is possible to know the change of the light flux from the reference optical axis shown in FIG. 6, and the deflection mirror 2 corresponding thereto can be known.
The rotation angle of 6 can be detected. Only the 0th-order light is incident on the objective lens 10 through the opening 340H formed in the photodetector 40. Further, the aperture limiting plate 345 can be omitted if there is no risk that a light beam other than the zero-order light will enter the objective lens 10.

FIG. 35 is a block diagram of the tracking control system. The tracking control system controls the fine movement tracking of the rotating arm 3 and the deflection mirror 26. The output signals of PSD 340a and 340b are C
It is input to the PU 150. CPU150 is PSD34
The current rotation position of the deflection mirror 26 is detected based on the signals from 0a and 340b. It should be noted that in the present embodiment, the number of PSDs may be one, and when there are a plurality of PDSs, for example, the average value of the turning positions of the deflection mirrors detected by each PDS may be used as the detection value. To be

When performing fine tracking, the CPU 150
Calculates how much the deflecting mirror 26 is further rotated from the present rotating position of the deflecting mirror 26 based on the output of the tracking detection sensor, and obtains the rotating position of the deflecting mirror 26 after performing the fine movement tracking. . If,
If the turning position of the deflecting mirror 26 after the fine movement tracking is within a predetermined turning range, the CPU 150 controls the driver 127 to drive the galvano motor 27 and turn the deflecting mirror 26 to make a fine movement. Perform tracking.

If the turning position of the deflection mirror 26 after the fine movement tracking exceeds the position within the predetermined turning range, the CPU 150 does not perform the fine movement tracking by the deflection mirror 26, and the calculated deflection mirror 26. The rotation position of is converted into the movement position of the rotation arm 3. And C
The PU 150 controls the driver 116 to drive the drive coil 1
By driving 6 to rotate the rotating arm 3, tracking is performed not by the deflection mirror 26 but by the rotating arm 3. By this control, the deflection mirror 26 can be prevented from rotating beyond a predetermined range, and deterioration of optical performance can be suppressed. If necessary, it is possible to further perform fine movement tracking by the deflecting mirror 26 after this.

With the above structure, the incident angle of the laser beam with respect to the objective optical system provided at the tip of the coarse movement arm that moves in the direction intersecting the track of the magneto-optical disk is finely adjusted by the deflecting means such as a galvano mirror. In an optical information recording device that accurately performs fine movement tracking, it is possible to accurately detect the amount of mirror rotation of the deflection mirror, and therefore it is possible to accurately implement fine movement tracking without degrading optical performance.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of a magneto-optical disk device according to an embodiment.

FIG. 2 is a diagram showing a tip portion of a rotating arm.

FIG. 3 is a cross-sectional view showing a floating type optical unit.

FIG. 4 is a plan view showing a deflection mirror and a floating optical unit.

FIG. 5 is a side sectional view of a rotating arm.

FIG. 6 is an arrangement diagram of optical elements of an optical system configured to be able to detect the rotation amount of the polarization mirror.

FIG. 7 is a diagram showing a structure of a diffraction grating.

FIG. 8 is a diagram showing a configuration of a photodetector.

FIG. 9 is a diagram showing a configuration of a spatial filter.

FIG. 10 is a diagram showing an optical path when a polarization mirror is rotated.

FIG. 11 is a diagram showing positions of light fluxes of 0th-order light and ± 1st-order light incident on the photodetector when the polarization mirror is rotated.

FIG. 12 is a diagram showing the positions of 0th-order light and ± 1st-order light that are incident on the spatial filter when the polarization mirror is rotated.

FIG. 13 is a block diagram of a control system for performing fine movement tracking.

FIG. 14 is a layout diagram of optical elements of an optical system configured to be able to detect the rotation amount of the polarization mirror.

FIG. 15 is a side sectional view of the optical system shown in FIG.

FIG. 16 is a diagram showing a configuration of a photodetector.

FIG. 17 is a diagram showing a configuration of a spatial filter.

FIG. 18 is a diagram showing an optical path when a polarization mirror is rotated.

FIG. 19 is a diagram showing the positions of light fluxes of 0th-order light and ± 1st-order light incident on the photodetector when the polarization mirror is rotated.

FIG. 20 is a diagram showing the positions of 0th-order light and ± 1st-order light incident on the spatial filter when the polarization mirror is rotated.

FIG. 21 is a block diagram of a control system for performing fine movement tracking.

FIG. 22 is an arrangement diagram of optical elements of an optical system configured to be able to detect the rotation amount of the polarization mirror.

FIG. 23 is a diagram showing a structure of an aperture limiting plate.

FIG. 24 is a diagram showing a configuration of a photodetector.

FIG. 25 is a diagram showing an optical path when a polarizing mirror is rotated.

FIG. 26 is a diagram showing positions of 0th-order light beams and ± 1st-order light beams incident on the aperture limiting plate when the polarization mirror is rotated.

FIG. 27 is a diagram showing positions of 0th-order light and ± 1st-order light incident on the photodetector when the polarization mirror is rotated.

FIG. 28 is a layout diagram of optical elements of an optical system configured to be able to detect the rotation amount of the polarization mirror.

FIG. 29 is an optical layout diagram showing a configuration of a detection device for detecting the rotation amount of the polarization mirror.

FIG. 30 is a diagram showing a configuration of an aperture limiting plate.

FIG. 31 is a diagram showing a configuration of a photodetector.

FIG. 32 is a diagram showing an optical path when a polarization mirror is rotated.

FIG. 33 is a diagram showing the positions of the 0th-order light and ± 1st-order light beams incident on the aperture limiting plate when the polarization mirror is rotated.

FIG. 34 is a diagram showing the positions of 0th-order light and ± 1st-order light incident on the photodetector when the polarization mirror is rotated.

FIG. 35 is a block diagram of a control system for performing fine movement tracking.

[Explanation of symbols]

2 Optical Disc 3 Rotating Arm 6 Levitation Type Optical Unit 8 Flexure Beam 26 Deflection Mirror 29 First Relay Lens 30 Second Relay Lens (Imaging Lens) 40 Photodetector 45 Spatial Filter 50 Diffraction Grating 140 Photodetector 145 Space Filter 240 Photodetector 245 Aperture limiting plate 340 Photodetector

─────────────────────────────────────────────────── ─── Continuation of front page (31) Priority claim number Japanese Patent Application No. 9-322417 (32) Priority date November 8, 1997 (November 8, 1997) (33) Priority claim country Japan (JP) (56) References JP-A-4-315825 (JP, A) JP-A-5-342609 (JP, A) JP-A-7-153095 (JP, A) JP-A-11-259873 (JP, A) Kaihei 7-14184 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G11B ^7/ 09-7/22

Claims (17)

(57) [Claims] 1. A laser light source that emits parallel laser beams, an objective lens system that converges the laser beam emitted from the laser light source onto an optical disc, and a rotatable lens between the laser light source and the objective lens system. A deflecting mirror provided on the optical disc, wherein the incident angle of the laser beam incident on the objective lens system is changed by rotating the deflecting mirror, and the position of the laser beam converged on the optical disc is changed. A deflecting mirror and a relay lens system disposed between the deflecting mirror and the objective lens system, the relay lens system having at least first and second relay lens groups, the entrance pupil of the deflecting mirror and the objective lens system. And a diffraction grating arranged between the laser light source and the deflecting mirror, the relay lens system making A diffraction grating that splits the luminous flux into at least 0-order light and ± 1st-order diffracted light having a predetermined diffraction angle and makes the incident light on the deflection mirror; and receives the ± 1st-order diffracted light reflected by the polarization mirror to deflect the light. Rotation amount detecting means for detecting the rotation amount of the mirror,
A fine movement tracking device provided with the objective lens system, and a coarse movement tracking device provided with a rotating arm that is rotatable in a direction parallel to the recording surface of the optical disc; Based on the tracking detection means that generates a tracking error signal by receiving light, the tracking error signal generated by the tracking detection means, and the rotation amount of the deflection mirror detected by the rotation amount detection means, after fine movement tracking The rotational position of the deflection mirror is obtained, and if the rotational position is within a predetermined range, the fine movement tracking device is driven, and if the rotational position exceeds the predetermined range, the coarse movement tracking device is driven. Tracking control means,
An optical information recording / reproducing apparatus having: 2. A light-shielding means for transmitting only the 0th-order diffracted light reflected by the polarization mirror toward the objective lens system and preventing the ± 1st-order diffracted light from entering the objective lens system. The optical information recording / reproducing apparatus according to claim 1. 3. The method according to claim 1, wherein the detecting means detects the rotation amount of the deflection mirror based on the light amount of the ± first-order diffracted light reflected by the deflection mirror. Optical information recording / reproducing device. 4. The detection means includes at least two light receiving regions arranged in a direction orthogonal to a rotation axis of the deflection mirror and receiving at least a part of the ± first-order diffracted lights, respectively. The ± received by the light receiving area
4. The optical information recording / reproducing apparatus according to claim 1, wherein the turning position of the deflecting mirror is detected based on the light amount difference of the first-order diffracted light. 5. The detection means detects the amount of rotation of the deflection mirror based on the incident position of the ± 1st-order diffracted light reflected by the deflection mirror on the detection means. The optical information recording / reproducing apparatus described. 6. The diffraction grating has a plurality of linear grooves extending in a direction parallel to a rotation axis of the deflection mirror, and the detection means is arranged in a direction orthogonal to the rotation axis of the deflection mirror. It has two light receiving regions arranged side by side to respectively receive at least a part of the ± first-order diffracted light, and based on the light amount difference of the ± first-order diffracted light received by the two light-receiving regions, the deflection mirror rotation is performed. The optical information recording / reproducing apparatus according to claim 1, wherein a moving position is detected. 7. The optical information recording / reproducing apparatus according to claim 6, wherein the detecting means is provided between the deflecting mirror and the relay lens system. 8. The detection means has a plate member having the two light receiving regions formed therein, and an opening is formed in the plate member between the two light receiving regions, and the ± first-order diffracted light is formed. 8. The optical information according to claim 7, wherein a part of the light is received by each of the two light receiving regions, and the remaining part of the ± first-order diffracted light and the zero-order light are transmitted through the opening. Recording / playback device. 9. The first and second relay lens groups, which are provided between the first and second relay lens groups, prevent the remaining portion of the ± first-order diffracted light transmitted through the aperture of the plate member from entering the objective lens system. 9. The optical information recording / reproducing apparatus according to claim 8, further comprising a light blocking member configured such that the 0th-order light is incident on the objective lens system. 10. The detection means includes the first and second detectors.
7. The optical information recording / reproducing apparatus according to claim 6, wherein the optical information recording / reproducing apparatus is provided between the relay lens groups. 11. The detecting means includes a plate member having the two light receiving regions formed therein, and an opening is formed in the plate member between the two light receiving regions, and the ± first-order diffracted light is formed. 11. The optical information recording / reproducing apparatus according to claim 10, wherein at least a part of the light is received by the two light receiving regions, respectively, and only the 0th order light is transmitted through the opening. 12. A light blocking member provided between the deflection mirror and the relay lens system and having an opening,
The light blocking member blocks a part of the ± 1st order diffracted light, the opening allows the remaining part of the ± 1st order diffracted light and the 0th order light to pass through, and the two light receiving regions cover the opening of the light blocking member. The optical information recording / reproducing apparatus according to claim 11, wherein each of the remaining portions of the ± 1st-order diffracted light that has been transmitted is received. 13. The diffraction grating has a plurality of linear grooves extending in a direction orthogonal to a rotation axis of the deflection mirror,
The detection means are arranged in a direction orthogonal to the rotation axis of the deflection mirror and receive first and second light receiving regions for receiving at least a part of the + first-order diffracted light of the ± first-order diffracted light; A plate member arranged in a direction orthogonal to the rotation axis of the deflection mirror and provided with third and fourth light receiving regions for receiving at least a part of the minus first order diffracted light of the ± first order diffracted light. And has a rotation position of the deflection mirror based on the difference between the light amount of the light received by the first and third light receiving regions and the light amount of the light received by the second and fourth light receiving regions. The optical information recording / reproducing apparatus according to claim 1, wherein the optical information recording / reproducing apparatus detects. 14. The plate member is provided between the deflecting mirror and the relay lens system, and the first and second light receiving regions and the third and fourth light receiving regions are formed by:
A portion of the ± 1st-order diffracted light, which is not received in the first to fourth light receiving regions, is arranged in a direction parallel to the rotation axis of the deflecting mirror with an opening formed between the two, and the zero portion. 14. The optical information recording / reproducing apparatus according to claim 13, wherein the next light is transmitted through the opening. 15. The remaining portion of the ± first-order diffracted light that is provided between the first and second relay lens groups and that has passed through the opening of the plate member is prevented from entering the objective lens system, 15. The optical information recording / reproducing apparatus according to claim 14, further comprising a light blocking member configured so that only the 0th order light is incident on the objective lens system. 16. The diffraction grating has a plurality of linear grooves extending in a direction orthogonal to a rotation axis of the deflection mirror, and the detection means is provided between the first and second relay lens groups. And a plate member provided with at least one position detecting element extending in a direction orthogonal to the rotation axis of the deflecting mirror, wherein at least + 1st-order diffracted light or -1st-order diffracted light of the ± 1st-order diffracted light is included. A part is configured to converge on the position detection element, and the detection means is configured to rotate the deflection mirror based on a position of at least a part of the + 1st order diffracted light or the −1st order diffracted light on the position detection element. The optical information recording / reproducing apparatus according to claim 15, wherein a moving position is detected. 17. The at least one position detecting element has first and second position detecting elements arranged in a direction parallel to a rotation axis of the deflecting mirror, and the + 1st-order diffracted light and the -1st-order diffracted light are arranged. At least a part of each of the folding lights converges on the first and second position detection elements, respectively, and the plate member has an opening between the first and second position detection elements. The optical information recording / reproducing apparatus according to claim 16, wherein only the 0th-order light travels to the objective lens system through an opening.