JP2006260663A - Method for adjusting light source unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adjusting method for exactly irradiating each of desired tracks on a disk with light beams from a plurality of emission points regarding the adjusting method of a light source unit having a laser package and a collimator lens constituting an optical system for imaging the two emission points in the laser package having the two emission points to two tracks mutually distant by the predetermined number of tracks on the disk having many tracks formed like approximately concentric circles. <P>SOLUTION: Light axis adjustment by transferring the laser package 10 in a surface perpendicular to a light axis of the collimator lens 50, inclination adjustment of the laser package 10 in order to make each distance between each of the two emission points in the laser package 10 and the collimator lens 50 into equal distance, distance adjustment in the light axis direction between the laser package 10 and the collimator lens 50 and rotational angle adjustment around the light axis integrating the laser package 10 and the collimator lens 50 are performed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention forms images of two light emitting points in a laser package having two light emitting points on two tracks separated from each other by a predetermined number on a disk having a plurality of tracks formed substantially concentrically. let, constituting an optical system including an objective lens disposed in the collimator lens and the disc near constituting the light source unit together with the laser package, method of adjusting the light source unit.

  Type of disk-shaped storage medium by using light such as a conventional from the optical disc or a magneto-optical disk to write or read data is frequently used.

  Attempts to speed access to such storage medium is performed.

  As one of them, the access speed is improved by increasing the rotational speed of the storage medium (disk). However, there is a limit to increasing the rotation speed, and if the rotation speed is increased too much, access errors increase and the disk is damaged.

As another attempt to increase the access speed, for example, Patent Documents 1 and 2 propose to simultaneously access a plurality of points on a disk using a plurality of light emitting elements.
JP 2000-222768 A Special table 2002-507040 gazette

  As a typical example in the case of using a plurality of light emitting elements, the plurality of light emitting elements need to be arranged at positions that are considerably close to each other (for example, 50 μm to 180 μm). Therefore, in one semiconductor laser (LD) package, It is possible to arrange a plurality of light emitting points that emit light as a semiconductor laser. In this case, in order to accurately irradiate each desired track on the disk with light spots emitted from a plurality of light emitting points, the distance accuracy between the light emitting points in the LD package is set in the cross-track direction (radial direction of the disk). ) As an example, and the optical axis direction as an example must be pressed to about ± 3.3 μm. On the other hand, the actual positional accuracy when a plurality of light emitting points are arranged in one LD package is ± 3 μm as an example in the direction orthogonal to the optical axis, and the positional deviation in the optical axis direction is approximately ± 5 μm as an example. However, with this as it is, the position error of the light emitting point in the LD package is too large, and it is impossible to form an accurate light spot on each desired track on the disk. The techniques of the above-mentioned Patent Documents 1 and 2 cannot solve the problem of the position error.

  In view of the above circumstances, the present invention, for example, emits light from a plurality of light emitting points emitted from a light source unit including a laser package having a plurality of light emitting points having a positional error exceeding the required positional accuracy. It is an object of the present invention to provide a method for adjusting a light source unit for accurately irradiating each desired track on a disk.

The method of adjusting the light source unit of the present invention that achieves the above-described object provides a method for adjusting the two light emitting points in a laser package having two light emitting points on a disk having a plurality of substantially concentric tracks. each two tracks apart number is imaged, constituting an optical system including an objective lens disposed in the collimator lens and the disc near constituting the light source unit together with the laser package, there adjustment method of the light source unit Te,
And the optical axis adjustment by causing the laser package is moved in a plane perpendicular to the optical axis of the collimator lens,
Inclination adjustment of the laser package to make each distance between each of the two light emitting points in the laser package and the collimator lens equal,
And the distance adjustment of the optical axis between the laser package and the collimator lens,
It was integrated with the laser package and the collimator lens, and performing a rotation angle adjustment around the optical axis.

  According to the present invention, the light emitting point in the laser package is limited to two, and in addition to the optical axis adjustment and the distance adjustment described above, which are necessary for the adjustment of the conventional light source unit having only one light emitting point in the laser package. Since the tilt adjustment and the rotation angle adjustment are newly performed, each light emitted from each of the two light emitting points is directed to a desired track on the disc in the track crossing direction (radial direction of the disc). And the depth direction (optical axis direction) of the light spot can be adjusted so that the irradiation can be performed accurately.

Here, in the adjusting method of the light source unit of the present invention, the light source unit,
A lens supporting member for movably supporting the optical axis direction of the collimator lens,
Abuts the rear end of the lens support member, the member abutment freely be moved in the perpendicular two axial directions to the optical axis relative to the lens support member,
Is abutted against the member rear abutment holds the laser package, times around its uniaxial laser light emitted by rotating around a perpendicular uniaxial to the optical axis relative to the abutment member from the two light emitting points moving the butt freely be those with a jig,
The optical axis adjustment, the member butting performed by moving to the biaxial directions,
The tilt adjustment, a jig butting performed by rotating around said uniaxial,
Performed by moving the distance adjustment, a supported collimator lens on the lens support member in the optical axis direction,
The rotation angle adjustment is preferably performed by rotating the light source unit about the optical axis.

  When the light source unit configured as described above is employed, the above-described four adjustments, that is, the optical axis adjustment, the inclination adjustment, the distance adjustment, and the rotation angle adjustment described above can be performed easily and with high accuracy.

  According to the present invention as described above, even if a laser package having two light emitting points having a position error exceeding the required positional accuracy is used, the light emitted from each of the two light emitting points is on a desired track on the disk. It can be adjusted so that it can be irradiated accurately.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is a perspective view showing an outline of the mechanism of the optical disk apparatus.

  For example a spindle motor 101 for rotating the optical disc 200 on aluminum drive base 100 is fixed. Further, here, there are provided a movable mechanism 110 provided with an objective lens 111 and an electromagnetic coil 112, and a permanent magnet 121 arranged so as to sandwich the movable mechanism 110. The magnetic circuit having the electromagnetic coil 112 and the permanent magnet 121 constitutes a VCM (voice coil motor). When a current is supplied to the electromagnetic coil 112, the magnetic circuit is movable by the interaction between the current flowing through the electromagnetic coil 112 and the magnetic circuit. The drive unit 110 moves in the direction of arrow AA ′. The objective lens 111 is supplied with laser light from a laser diode, a collimator lens that converts laser light emitted from the laser diode into a parallel light flux, and a fixed optical unit 130 that includes a pickup optical system that picks up an optical signal, and the like. The light emitted from the objective lens 111 is irradiated with and reflected by the optical spot 200, and the reflected light returns to the fixed optical unit 130 through the objective lens 111 again, and information stored in the optical disk 200 is taken out.

  Figure 2 is a conceptual diagram of a laser package having two light emitting points.

  In the laser package 10, there are two light emitting points 10a and 10b. If the distance between the light emitting points 10a and 10b is too close, a thermal burden is applied to the laser element, so that the laser element cannot be brought too close. From these points, it is said that the interval between the light emitting points 10a and 10b is 50 to 100 μm.

  As shown in FIG. 2, the laser light beams 11a and 11b emitted from these two light emitting points 10a and 10b travel along an optical path in which a considerable portion thereof overlaps, reach the collimator lens 20, and are converted into parallel light beams.

  FIG. 3 is an explanatory diagram of the definition of the direction on the optical disc.

  On the optical disc 200, a large number of information recording tracks 210 are formed in a substantially concentric shape (actually a spiral shape), and light spots 10c and 10d are irradiated on the tracks to write and read information. .

  Here, the direction in which the track extends (circumferential direction of the optical disc 200) is referred to as “track direction”, and the direction crossing the track (radial direction of the optical disc 200) is referred to as “track crossing direction”.

  FIG. 4 is an explanatory view showing the relationship between the cylindrical surface abutting jig and the laser package, FIG. 5 is a sectional view of the light source unit in the direction along the optical axis, and FIG. 6 is a lens mirror constituting the light source unit. It is a perspective view of a trunk.

  In constructing the light source unit 1 as shown in FIG. 5, the laser package 10 having two light emitting points described with reference to FIG. As shown in FIG. 4 (B), the laser package 10 is joined with an adhesive or the like so that the tip end portion of the laser package 10 protrudes slightly from the cylindrical surface abutting jig 20 as shown in FIG. .

  The cylindrical surface abutting jig 20 has a cylindrical convex surface 21 on the front surface, and an opening (not shown) into which the laser package 10 is fitted is formed at the center of the cylindrical surface abutting jig 20. there.

  The light source unit 1 shown in FIG. 5 includes a cylindrical surface abutting jig 20 joined to the laser package 10, a abutting plate 30, a lens barrel 40, and a collimator lens 50 described with reference to FIG. 4. It is composed of a.

  A cylindrical concave surface 31 is formed on the rear surface of the abutting plate 30 and has a shape that matches the cylindrical convex surface 21 of the cylindrical surface abutting jig 20. The cylindrical convex surface 21 of the cylindrical surface abutting jig 20 is abutted against the cylindrical convex surface 21. It is abutted against the cylindrical concave surface 31 of the plate 30.

  Further, the abutting surface 32 on the front surface of the abutting plate 30 is abutted against the back surface of a cylindrical (or semi-cylindrical (not shown)) lens barrel 40 as shown in FIG. Furthermore the hollow portion of the lens barrel 40, the collimator lens 50 is disposed.

  Here, the definition of the direction is shown in FIG. 5, the optical axis direction of the collimator lens 50 is the z direction, the z direction is perpendicular to the z direction, and the x direction from the direction along the paper surface of FIG. A direction perpendicular to both the z direction and the x direction from the front side to the back side in FIG. 5 is defined as the y direction.

  Also, [theta] y shown in FIG. 5, [theta] z represents the rotation around a rotation axis parallel to the rotation, z-axis around the rotation axis parallel to the y-axis, respectively.

  In the light source unit 1 shown in FIG. 5, before the adjustment (before fixing), when the lens barrel 40 is fixed, the collimator lens 50 is moved in the z direction and the position thereof is adjusted. Translate in two axial directions, the x direction and the y direction. Further, the cylindrical surface abutting jig 20 rotates in a rotation direction (θy direction) having a rotation axis parallel to the y axis. Further, the light source unit 1 is united and rotated in the rotation direction (θz direction) with the z axis as the rotation axis.

  FIG. 7 is a schematic diagram of a measuring apparatus for adjusting the light source unit 1.

  This measuring apparatus 2 includes a biaxial rotating stage 60 on which the light source unit 1 having the structure shown in FIG. 5 is mounted, a light source unit 70, an autocollimator unit 80, a self-luminous wavefront measuring unit 90, and several beam splitters 71. 72, mirror 73, a CCD sensor for detecting the irradiation position of laser light in the autocollimator unit 80 (not shown), a CCD sensor for detecting the interference fringes obtained by the self-luminous wavefront measuring unit 90, an interference fringe analyzer, etc. It is constructed from.

  Here, the self-luminous wavefront measuring unit 90 is of a radial shearing interference type, and the measurement principle using the self-luminous wavefront measuring unit 90 and the autocollimator unit 80 is widely known. The description of the surface measuring unit 90 and the autocollimator unit 80 will be made only on the points necessary for the adjustment of the light source unit 1.

  The light source unit 1 is mounted on the biaxial rotary stage 60. The biaxial rotary stage 60 is parallel to the y axis shown in FIG. 5, that is, around a rotary axis perpendicular to the paper surface of FIG. The traveling direction of the laser light that is rotated and emitted from the light source unit 1 is swung within the paper surface of FIG. 7, and is rotated around a rotation axis parallel to the x axis shown in FIG. The traveling direction of the laser beam can be swung in a direction perpendicular to the paper surface of FIG. 7, and the traveling direction of the laser beam emitted from the light source unit 1 and the optical axis of the measuring device 2 are matched by the rotation of these two axes. It is configured to be able to.

  The light source unit 70 emits a reference laser beam 70a for autocollimator reference detection. The reference laser beam 70a passes through the beam splitter 71 and is reflected by the other beam splitter 72 to be reflected on the reference surface of the light source unit 1. (e.g. the front surface of the lens barrel 40 or not shown, the holding member front the like for holding the collimator lens 50 directly) is applied to the. The reference laser light reflected and returned from the reference surface is reflected by the beam splitter 72, reflected by the beam splitter 71, reflected by the mirror 73, and enters the autocollimator unit 80. Figure 7 is a schematic diagram 81 that represents the optical spot S0 by the reference laser beam on the autocollimator section 80 by a white circle is shown. In this schematic diagram 81, the light spots S1 and S2 indicated by white circles on both sides of the light spot S0 are the light spots S1 after the following adjustment by the two laser beams emitted from the laser package 10. , S2.

  The self-luminous wavefront measuring unit 90 includes two systems, an optical system including a zoom lens 91a, a pinhole 92a, and a coupling lens 93a, and an optical system including a zoom lens 91b, a pinhole 92b, and a coupling lens 93b. An optical system is provided. This is because there are two light emitting points 10a and 10b in the laser package 10 (see FIG. 2), and the light is emitted from one of the two light emitting points 10a and 10b. Only the laser beam that has been extracted is extracted by one of the two pinholes 92a and 92b to serve as a reference wave, and only two laser beams emitted from the other of the two light emitting points 10a and 10b This is a device for extracting a reference wave from the other pinhole of the pinholes 92a and 92b.

  Next to the self-wave light wavefront measuring unit 90, interference fringes 94a and 94b are obtained by the laser beams from the two light emitting points 10a and 10b (see FIG. 2) obtained by the self-wave light wavefront measuring unit 90. It is shown schematically. When observing the interference fringes 94a and 94b of the laser light from the two light emitting points 10a and 10b, the two light emitting points 10a and 10b are sequentially turned on one by one, and the two interference fringes 94a and 94b are sequentially turned on. to observe to.

  Here, it is assumed that for adjusting the light source unit 1 under the following conditions as an example.

The wavelength of the two laser beams emitted from the two light emitting points 10a and 10b in the laser package 10: both are 405 nm
Objective lens 111 (see FIG. 1): NA = 0.85, focal length f = 1.8 mm
Collimator lens 50: focal length f = 12 mm
-Beam shaping magnification: 2 times (track direction)
It is assumed that the beam shaping prism is manufactured by joining two glass materials having different dispersions, and the respective dispersions are selected so that the exit angle deviation for the slight deviation of the oblique incidence angle is the same for the two beams. This is not particularly shown here.

Laser emitting point interval: the optical axis (z axis) 0 ± 5 [mu] m
: Plane 80 ± 3 [mu] m perpendicular to the z-axis
· Optical disc on spot irradiation required accuracy (for each of the two spots)
The cross-track direction: ± 0.05μm
The optical axis (z-axis) direction: ± 0.075 .mu.m
Under the above-mentioned conditions, the focal point of the collimator lens 50 and the objective lens 111 is set to be within the required spot irradiation accuracy (track crossing direction: ± 0.05 μm, optical axis (z-axis) direction: ± 0.075 μm). from the magnification of the relationships determined from the distance, two light emitting points 10a of the laser package 10, the positional accuracy of 10b (see FIG. 2),
Track transverse: ± 0.333μm (= 0.05 × 12 ÷ 1.8)
Optical axis direction: ± 3.33μm (= 0.075 × 12 2 ÷ 1.8 2)
However, this value is considerably stricter than the manufacturing tolerance of the two light emitting points 10a and 10b in the laser package 10 described above (track crossing direction: ± 3 μm, optical axis direction ± 5 μm). cage, optical disks of a plurality in the conventional light sources are not produced. This embodiment, the adjustment of the light source unit 1 is intended to be Motaseyo the production suitability.

  Adjustment of each part of the light source unit 1 shown in FIG. 5 has the following meaning.

(A) Rotation of θy of Cylindrical Seat Abutting Jig The optical axis spot irradiation accuracy on the optical disk due to the correction of the laser emission point interval of 0 ± 5 μm is set to ± 0.075 μm.

(B) Movement of the abutting plate 30 in the x and y directions The two emission lights from the collimator lens 50 are set to have uniform emission angles with respect to the light source unit reference surface.

(C) to the parallel movement of two light emitted z-direction of the collimator lens 50. Difference parallelism deviation is adjusted by θz jig 20 abutting cylindrical surfaces seat.

(D) of the entire light source unit rotation angle θz
Correcting an error of the light emitting point interval 80 ± 3 [mu] m, a and ± 0.05 .mu.m track transverse spot irradiation accuracy.

  Here, the light source unit 1 is adjusted by the following procedure using the adjusting device 2 shown in FIG.

  Figure 8 is a diagram showing the position and size of the light spot on the CCD sensor (not shown) in the autocollimator section 80 in FIG. 7 by white circles.

  (1) The reference laser beam 70a from the light source unit 70 is irradiated onto the reference surface of the light source unit 1, and the light spot 80 by the reference laser beam reflected from the reference surface is a CCD sensor as shown in FIG. to come to the center of the biaxial rotation stage 60, about the y-axis parallel to the rotation axis, and the x-axis and rotates around a rotational axis parallel.

Here, from the interval between the two light emitting points and the focal length of the collimator lens, the maximum two laser beams emitted from the collimator lens are sin ⁻¹ (86 μm / 12 mm) = 0.106106 deg (a)
With the angle difference. Here, 86 μm is the distance 80 μm + 6 μm = 86 μm when the distance between the two light emitting points is 80 μm ± 3 μm, and 12 mm is the focal length of the collimator lens.

  The angle represented by the equation (a) is an angle that fits in the field of view of a general autocollimator.

  (2) Next, the angle θy of the cylindrical surface abutting jig 20 is aligned so that, for example, the back surface of the cylindrical surface abutting jig 20 and the back surface of the abutting member 30 are in parallel with each other. The abutting member 30 is moved in the x and y directions, and as shown in FIG. 5, the two light spots S1 and S2 by the laser beams emitted from the two light emitting points 10a and 10b are both CCD sensors in the autocollimator section. The state is formed on the top. Here, if an autocollimator that can switch between two fields of view of high magnification and low magnification is employed as the autocollimator unit 80, the time required for adjustment to reach the state of FIG. 8B can be shortened.

  (3) When two light spots S1 and S2 are formed on the CCD sensor as shown in FIG. 8B, automatic adjustment is possible thereafter, and the area center of the two light spots S1 and S2 is auto. The abutting plate 30 is moved by automatic adjustment in the x and y directions so as to be symmetric with respect to the reference point of the collimator (the point of the light spot S0 in FIG. 8A), and the state of FIG. to.

  (4) then to grasp the positional relationship between two light spots S1, S2 and the collimator lens 50 in the state of FIG. 8 (C). Specifically, the maximum luminance value and area of the two light spots S1 and S2 are measured in real time while moving the collimator lens 50 in the z-axis direction, and the average value and area of the maximum luminance values of the two light spots S1 and S2 are measured. tentative to the position of the collimator lens 50 as an evaluation function and the average value of. FIG. 8D schematically shows the light spots S1 and S2 when this provisional decision is made.

  (5) then performing self-emission monitored using self-emission wavefront measurement section 90. The self-emission wavefront measuring unit 90 in FIG. 7 is used when the two light emitting points 10a and 10b in the laser package 10 are spaced at a distance of 80 μm as the median value (when the difference in inclination between the two parallel light beams is an amount corresponding thereto). From both of the two interference fringes 94a and 94b, there is no striped pattern corresponding to the Zernike cross-track direction tilt component, that is, when correctly adjusted, the striped pattern disappears from both interference fringes 94a and 94b. Optical members such as zoom lenses 91a and 91b, pinholes 92a and 92b, and other mirrors of two optical paths are set. Therefore, if the distance between two light emitting points is deviated from 80 [mu] m, the interference fringes 94a, the 94b stripes A pattern of the shift amount is generated. That is, when the biaxial rotating stage 60 is driven to adjust so that the stripe pattern disappears from one of the two interference fringes 94a and 94b, the number of stripes of the other interference fringe increases accordingly. .

  (6) The θy of the cylindrical surface abutting jig 20 and the z-direction position of the collimator lens 50 are adjusted according to the amount of defocus aberration and the sign obtained by the self-light emission observation.

  (7) Thereafter, as shown in FIG. 8D, it is confirmed whether or not the center position is maintained. If not, the positions of the butting plate 30 in the x and y directions are adjusted.

  (8) Finally, until the defocus amounts of both the light emitting points 10a and 10b are sufficiently small, that is, until the concentric components of both interference fringes 94a and 94b are sufficiently small to be sufficiently parallel fringes (6) after repeating the (7), to fix the respective parts of the light source unit 1 with an adhesive or the like.

  By performing the wavefront aberration measurement detection of the defocus error of 10mλrms is easy, the NA = 0.85, the defocus error corresponds to 0.03 .mu.m. Here, it is assumed to be adjusted to within ± 0.075 .mu.m for the optical axis direction, which corresponds to ± 25mλrms. Therefore, adjustment of the optical axis direction ± 0.075 .mu.m is readily achievable.

  In this example, the wavelengths of the laser beams emitted from the two light emitting points 10a and 10b are both 405 nm. However, the wavelengths of the laser beams emitted from the two light emitting points 10a and 10b are different from each other. Even if the respective wavelengths are known, even if the objective lens does not have the chromatic aberration correction function, the two laser beams after being emitted from the collimator lens 50 are intentionally degenerated so as to correct them. It is also possible to leave the focus aberration.

  Figure 9 is a schematic view showing an adjustment sequence of the above (6) to (8).

  The self-emission measurement is performed by turning on only one of the two light emitting points 10a and 10b, and the Zernike power value (defocus aberration) is measured (FIG. 9A). Self-emission measurement is performed with only the light emitting point on the other side of the points 10a and 10b turned on to measure the power value (defocus aberration) of the Zernike (FIG. 9B), and the power value of the Zernike ( From the two values of (defocus aberration), the θy correction amount of the cylindrical surface abutting jig 20 and the position correction amount of the collimator lens 50 in the z direction are determined and adjusted. After the adjustment, the positions of the light spots S1 and S2 in the autocollimator portion by the laser beams emitted from the two light emitting points 10a and 10b are confirmed (FIG. 9D). The two light spots S1 and S2 are moved in the x direction or the y direction and adjusted so that they are positioned at an equal position with respect to the light spot S0 by the reference laser light reflected by the reference surface of the light source unit 1 (FIG. 9 ( E)). Perform self-emission measurement again for confirmation. This process is repeated until the laser power from any of the light emitting points 10a and 10b is adjusted until the Zernike power value (defocus aberration) becomes a predetermined value or less, and then each part of the light source unit 10 is fixed by bonding or the like. .

  This completes the adjustment of the light source unit 1 as a single unit. Next, the optical disc is irradiated so that the two light beams emitted from the light source unit 1 are irradiated onto a predetermined number of separated tracks on the optical disc. The rotation angle θz of the light source unit 1 as a whole is adjusted.

  As described in (5), if the wavefront aberration corresponding to the Zernike tilt component in the track crossing direction is measured, that is, if the number of remaining fringes corresponding to the track crossing direction is counted, the two light emitting points 10a and 10b Since the deviation amount of the interval from 80 μm can be grasped, this deviation amount may be obtained and the entire rotation angle θz of the light source unit 1 may be adjusted according to the deviation amount, but the light spot is on the track of the optical disc. because there is also offset in the tracking circuit to be adjusted to continue to be irradiated, it will be described here a method for correcting collectively including its offset.

  Figure 10 is a schematic diagram of an optical disk apparatus using the light source unit 1. The laser light emitted from the light source unit 1 passes through the pickup main body 3 and is irradiated onto the optical disc 200. The reflected light of the optical disc 200 enters the pickup main body 3, and a tracking error is detected by the tracking error detection sensor 3a. . The configurations of the pickup body 3 and the tracking error detection sensor 3a are widely known, and a detailed description thereof is omitted here. Here, the whole of the light source unit 1, the rotation angle θz about the z-axis is adjusted. In this adjustment, an optical disc for adjustment in which predetermined reference data is written in advance is used as the optical disc 200.

  FIG. 11 is an explanatory diagram of the adjustment method described below.

  (9) The light source unit 1 is rotated in the θz direction so that the offset values of the tracking error signals due to the laser beams emitted from the two light emitting points 10a and 10b are equal for the two laser beams.

  (10) Next, fine adjustment is performed while measuring the jitter of the signal actually picked up from the optical disc 200 (FIG. 11B), and it is confirmed that the difference in offset value after this fine adjustment does not exceed 15%. and (FIG. 11 (C)), to fix the light source unit 1 remains in its rotational angle [theta] z.

  Since the track width is approximately 0.3 μm, the target ± 0.05 μm can be achieved if the offset difference is suppressed to less than 15% of the amplitude. Detection of 15% of the amplitude has no problem at all.

  As described above, in the past, when the light source was single, there were two adjustment locations and three adjustment axes of x and y of the abutting plate 2 and the collimator lens z, but this embodiment is a new cylindrical surface. By providing two adjusting means, θy of the seat bump jig 20 and rotation θz of the light source unit 1, the optical disk can be accessed using two laser beams from the two light emitting points 10a and 10b. .

Note that Δ is the minimum interval that takes into account the design center value of the interval between the two light emitting points, and the interval between the two tracks that respectively irradiate the two light spots on the optical disk is n × T (T Is the track width and n is an integer)
Δ> n × T ... (b)
There needs to be. By designing so as to satisfy the relationship of the expression (b), correction can be made by the entire rotation (θz) of the light source unit 1.

  The jig 20 abutting cylindrical surfaces seat was a cylindrical surface seat may be a spherical seat in consideration of ease of machining. However, in that case, it is necessary to adjust in consideration of the shift of θx, and the rotation about one axis is essentially sufficient.

It is a perspective view which shows the outline | summary of the mechanism of an optical disk apparatus. It is a conceptual diagram of the laser package with two light emitting points. It is explanatory drawing of the definition of the direction on an optical disk. It is explanatory drawing which shows the relationship between a cylindrical surface seat butting jig | tool and a laser package. It is sectional drawing of the direction in alignment with the optical axis of a light source unit. It is a perspective view of the lens barrel which comprises a modulation unit. It is a schematic diagram of the measuring apparatus for adjustment of a light source unit. It is the figure which showed the spot position and magnitude | size on a CCD sensor (not shown) in the autocollimator part of FIG. 7 with the white circle. It is the schematic diagram which showed the adjustment sequence. It is a schematic diagram of the optical disk apparatus using a light source unit. It is an explanatory view of the adjustment process.

Explanation of symbols

100 drive base 111 objective lens 200 optical disc 210 track 1 light source unit 2 measuring device 3 pickup main body 3a tracking error detecting sensor 10 laser package 10a, the surface 40 10b emission point 20 jig 21 cylindrical convex 30 abutting plate 31 cylindrical concave 32 butting the lens barrel 50 collimator lens 60 biaxial rotation stage 70 light source unit 70a the reference laser beam 71 beam splitter 73 mirror 80 autocollimator section 90 self-emission wavefront measurement section 91a, 91b zoom lens 92a, 92b pinholes 93a, 93 b coupling lens 94a, 94b interference fringes

Claims (2)

The laser that images the two light emitting points in a laser package having two light emitting points on two tracks separated from each other by a predetermined number on a disk having a plurality of tracks formed substantially concentrically. constituting an optical system including an objective lens disposed in the collimator lens and the near said disc constituting the light source unit with the package, a method of adjusting a light source unit,
And the optical axis adjustment by moving the laser package in a plane perpendicular to the optical axis of the collimator lens,
And the for the same distance, inclination adjustment of the laser package each distance between the two light emitting points and each of the collimator lens in said laser package,
And the distance adjustment of the optical axis between the laser package and the collimator lens,
Adjusting method of the light source unit and performs the integral and the collimator lens and the laser package, and a rotation angle adjustment around the optical axis. Said light source unit,
A lens supporting member for movably supporting the optical axis direction of the collimator lens,
Is abutting the rear end of the lens support member relative to said lens supporting member, and the member moved to perpendicular two axial directions to the optical axis is freely abutting,
A holding jig that holds the laser package and is abutted against the back surface of the abutting member, and is rotatable in a single axis perpendicular to the optical axis with respect to the abutting member;
The optical axis adjustment, the member the abutment carried by moving in the biaxial directions,
The tilt adjustment, carried out by rotating the jig around the uniaxially said abutment,
The distance adjustment, carried out by moving in the optical axis direction the collimator lens supported by the lens supporting member,
The rotation angle adjustment, the adjustment method of the light source unit of claim 1, wherein the performed by rotating the light source unit about the optical axis.

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