JP3912708B2 - Lens frame position adjusting method and position adjusting apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lens frame position adjusting method and a position adjusting apparatus.
[0002]
[Prior art]
Recently, development of a magneto-optical disk apparatus having a surface recording density exceeding 10 Gbit / (inch) 2 is in progress. It is necessary to attach components such as a lens frame used in the optical system of such an apparatus with high accuracy.
[0003]
FIG. 10 shows an example of a conventional lens frame position adjustment method. It is assumed that the lens frame 500 has a cylindrical shape and is placed so that its axial direction is horizontal. The direction in which the lens frame 500 is moved in accordance with the position adjustment is assumed to be the front-rear direction (left-right direction in the figure). On the upper side of the outer peripheral surface of the lens frame 500, a recess 502 for engaging the operation jig 510 is formed. The operation jig 510 is a shaft member provided with an eccentric pin 512 at the tip, and the eccentric pin 512 moves in the front-rear direction by the rotation of the operation jig 510, whereby the lens frame 500 moves in the front-rear direction.
[0004]
[Problems to be solved by the invention]
However, in such a method, the contact point between the pin 512 and the concave portion 502 and the center of gravity P of the lens frame 500 (generally at the center of the lens frame in the axial direction and radial direction) P are separated. For this reason, there is a problem in that the lens frame 500 tilts due to a counterclockwise or clockwise moment M in the figure accompanying the position adjustment of the lens frame 500.
[0005]
In view of the above-described problems, an object of the present invention is to enable position adjustment without tilting a lens frame.
[0006]
[Means for Solving the Problems]
The present invention has been made in view of the above-described background, and a lens frame position adjustment method according to claim 1 is a method of moving a surface parallel to a moving direction and including a substantial center of gravity of a lens frame, It is characterized in that a force is applied to the lens frame at two points substantially positioned on an intersection line perpendicular to the direction and intersecting with a plane including the approximate center of gravity of the lens frame. In this way, since a moment for tilting the lens frame does not occur, the tilt of the lens can be prevented.
[0007]
According to a seventh aspect of the present invention, there is provided a lens frame position adjusting device comprising: an operating member that applies a force to the lens frame to move the lens frame; It is characterized in that the two points are located substantially on the intersection line between the plane including the approximate center of gravity of the frame and the plane perpendicular to the moving direction and including the approximate center of gravity of the lens frame.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
First, recording called near field recording (NFR) technology, which was proposed in response to the increasing demand for external storage devices, especially the demand for large storage capacity, as hardware and software have advanced in recent years An outline of a magneto-optical disk recording / reproducing apparatus using a reproducing method will be described with reference to FIGS.
[0009]
FIG. 1 is an overall schematic diagram of the optical disk apparatus. In the disk drive device 1, an optical disk 2 is mounted on a rotating shaft of a spindle motor (not shown). On the other hand, a rotating (coarse movement) arm 3 is attached so as to be parallel to the recording surface of the optical disc 2 in order to reproduce or record information on the optical disc 2. The rotating arm 3 can be rotated about a rotating shaft 5 by a voice coil motor 4. A floating optical head 6 on which an optical element is mounted is mounted on the tip of the rotating arm 3 facing the optical disk 2. Further, a light source module 7 including a light source unit and a light receiving unit is disposed in the vicinity of the rotation shaft 5 of the rotation arm 3, and is configured to be driven integrally with the rotation arm 3.
[0010]
2 and 3 illustrate the tip of the rotating arm 3, and in particular, the floating optical head 6 will be described in detail. The floating optical unit 6 is attached to the flexure beam 8 and is disposed to face the optical disc 2. The flexure beam 8 is fixed to the rotating arm 3 at the other end, and is pressurized in a direction in which the floating optical unit 6 at the tip is brought into contact with the optical disc 2 by the elastic force of the flexure beam 8.
[0011]
The flying type optical unit 6 includes a flying slider 9, an objective lens 10, a solid immersion lens (SIL) 11, and a magnetic coil 12, and converges a parallel laser beam 13 emitted from the light source module 7 onto the optical disk 2. Work. Further, a rising mirror 31 is fixed to the tip of the rotating arm 3 in order to guide the laser beam 13 to the floating optical unit 6. The laser beam 13 incident on the objective lens 10 by the rising mirror 31 is converged by the refraction action of the objective lens 10. A solid immersion lens (SIL) 11 is disposed in the vicinity of the condensing point, and irradiates the optical disc 2 with the convergent light as finer evanescent light 15.
[0012]
A magnetic coil 12 for recording by a magneto-optical recording system is formed around a solid immersion lens (SIL) 11 facing the optical disk 2, and a magnetic field necessary for recording is applied on the recording surface of the optical disk 2. It can be applied.
The evanescent light 15 and the magnetic coil 12 enable high-density recording and reproduction on the optical disc 2. Note that the floating optical unit 6 floats by a minute amount due to the air flow caused by the rotation of the optical disc 2, and follows surface vibration of the optical disc 2. For this reason, the focus control (focus servo) of the objective lens, which was necessary in the conventional optical disc apparatus, is not required.
[0013]
Hereinafter, the light beam guided to the light source module 7 and the floating optical unit 6 mounted on the rotating arm 3 will be described in detail with reference to FIGS. The rotating arm 3 has a floating optical unit 6 mounted at the tip, and a driving 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 disposed in a magnetic circuit (not shown) with a gap. The rotating shaft 5 and the rotating arm 3 are fastened by bearings 17 and 17 so as to be rotatable. When a current is applied to the drive coil, the rotating arm 3 is rotated about the rotating shaft 5 by the electromagnetic action with the magnetic circuit. Can be moved.
[0014]
The light source module 7 mounted on the rotating arm 3 includes a semiconductor laser 18, a laser driving circuit 19, a collimating lens 20, a composite prism assay 21, a laser power monitor sensor 22, a reflecting prism 23, a data detection sensor 24, and tracking detection. A sensor 25 is arranged. The divergent light beam emitted from the semiconductor laser 18 is converted into a parallel light beam by the collimator lens 20. The cross-sectional shape of the parallel light flux is oblong due to the characteristics of the semiconductor laser 18, and it is inconvenient to finely focus the light beam on the optical disk 2, so it is necessary to convert it into a substantially circular cross-section. Therefore, the cross-sectional shape of the parallel light beam is shaped by causing the parallel light beam having an elliptical cross section emitted from the collimator lens 20 to enter the composite prism assay 21.
[0015]
The incident surface 21a of the composite prism assay 21 forms a predetermined slope with respect to the incident optical axis, and the sectional shape of the parallel light beam can be shaped from an oval shape to a substantially circular shape by refracting the incident light. . The shaped laser beam travels through the composite prism assay 21 and enters the first half mirror surface 21b. The first half mirror surface 21b is set to guide the information obtained from the optical disc 2 to the data detection sensor 24 and the tracking detection sensor 25, but the output of the laser emitted from the semiconductor laser 18 in the forward path. It plays the role of separating the light flux to the laser power monitor sensor 22 for detecting the power.
[0016]
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 beam 13 having a substantially circular cross-sectional shape emitted from the composite prism assay 21 is irradiated to the galvanometer mirror 26, and the traveling direction of the laser beam 13 is changed. The galvanometer mirror 26 is rotated about an axis perpendicular to the paper surface, and the laser beam 13 can be shaken by a minute angle in a direction parallel to the paper surface.
[0017]
The galvanometer mirror 26 is for fine movement tracking. That is, when the galvanometer mirror 26 is rotated, the incident angle of the laser beam 13 incident on the objective lens 10 is changed, and the focused beam is moved in the tracking direction on the optical disc 2 to perform accurate tracking control. Done. Note that the access operation over the inner periphery / outer periphery of the optical disc 2 is performed by rotating the rotating arm 3 and only the very small tracking control is performed by rotating the galvano mirror 26.
[0018]
Behind the galvanometer mirror 26, a mirror position detection sensor 28 for detecting the rotation angle of the galvanometer mirror 26 is disposed. The laser light beam 13 reflected by the galvanometer 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 and reaches the floating optical unit 6. The first relay lens 29 and the second relay lens 30 have a conjugate relationship between the reflecting surface of the galvano mirror 26 and the pupil plane (main plane) of the objective lens 10 arranged in the floating optical unit 6. Thus, a relay lens optical system is formed.
[0019]
Here, if fine tracking is performed by rotating the galvanometer mirror, when the optical distance between the galvanometer mirror 26 and the objective lens 10 is long, the amount of movement of the laser beam 13 incident on the objective lens 10 increases, and the objective lens 10 May not be able to enter. In order to avoid such a phenomenon, the first relay lens 29 and the second relay lens 30 set the relationship between the reflecting surface of the galvano mirror 26 and the pupil plane of the objective lens 10 to be a conjugate relationship, Even if the galvanometer mirror 26 rotates, the laser light beam 13 incident on the objective lens 10 does not move, and accurate tracking control is possible.
[0020]
The return laser beam 13 that has been reflected back from the optical disk 2 travels in the opposite direction to the forward path, is reflected by the galvanometer mirror 26, and enters the composite prism assay 21. Thereafter, the light is reflected by the first half mirror surface 21b and travels toward the second half mirror surface 21c. The second half mirror surface 21c generates transmitted light toward the tracking detection sensor 25 and reflected light toward the data detection sensor 24, and separates the laser beam on the return path. The laser beam transmitted through the second half mirror surface 21c is irradiated to the tracking detection sensor 25, and a tracking error signal is output.
[0021]
On the other hand, the laser beam reflected by the second half mirror surface 21 c is polarized and separated by the Wollaston prism 32, converted into convergent light by the condenser lens 33, reflected by the reflecting prism 23, and irradiated on the data detection sensor 24. Is done. The data detection sensor 24 has two light receiving areas, and receives the two polarized beams separated by the Wollaston prism 32, thereby reading the data information recorded on the optical disc 2 and outputting a data signal. More precisely, the tracking error signal and the data signal are generated by a head amplifier circuit (not shown) and sent to a control circuit or an information processing circuit.
[0022]
Next, the position adjustment of the lens frame of the collimating lens 20 will be described. 6 and 7 are a front view and a side view showing a lens frame 200 that holds the collimating lens 20 and an adjusting device 300 that adjusts the position of the lens frame 200. FIG. The collimating lens 20 is bonded and fixed to one end of the cylindrical lens frame 200 in the axial direction. In FIG. 6, the left side in the figure is the front and the right side in the figure is the rear. Further, the axial direction of the lens frame 200 coincides with the front-rear direction of FIG.
[0023]
As shown in FIG. 6, the lens frame 200 is attached to a base 100 provided on the rotating arm 3 (FIG. 4). The base 100 has a pentagonal cross section with a substantially V-shaped lower portion, and the lens frame 200 is abutted against two V-shaped inclined surfaces (contact surfaces 102). A leaf spring 104 that comes into contact with the upper surface of the lens frame 200 is attached to the base 100, and the lens frame 200 is urged against the contact surface 102 by the leaf spring 104.
[0024]
Two symmetrical slits 204 extending in the vertical direction are formed on the outer peripheral surface of the lens frame 200. As shown in FIG. 7, the slitting unit 204 is substantially located on a vertical plane (referred to as a B plane) passing through the center of gravity P of the lens.
[0025]
The adjusting device 300 has an operation lever 310 having a bifurcated tip. The distance between the bifurcated tip portions 312 of the operation lever 310 is slightly wider than the distance between the two slit portions 204 of the lens frame 200. The bifurcated tip 312 engages the two slits 204 from above so as to sandwich the lens frame 200.
[0026]
As shown in FIG. 7, projecting portions 314 and 316 having spherical surfaces are provided on the front and rear surfaces of the tip portion 312. The protruding portions 314 and 316 are opposed to the front and rear end surfaces 204 a and 204 b of the slit portion 204. Further, there is a slight clearance between the protruding portions 314 and 316 and the slit portion 204.
[0027]
The adjustment device 300 includes an X stage 320 and a Z stage 330 in order to drive the operation lever 310 back and forth and up and down. The X stage 320 includes a fixed portion 322 and a slider 324 that can move back and forth with respect to the fixed portion 322, and the slider 324 is configured integrally with the upper end of the operation lever 310. The Z stage 330 includes a fixed portion 332 and a slider 334 that can move up and down with respect to the fixed portion 332. The fixed portion 322 of the X stage 320 and the slider 334 of the Y stage are integrally formed in an L shape.
[0028]
When the position of the lens frame 200 is adjusted, first, the Z stage 330 is driven to engage the distal end portion 312 of the operation lever 310 with the slit portion 204. At this time, the protrusions 314 and 316 of the operation lever 310 are positioned on a horizontal plane (referred to as plane A) passing through the center of gravity P of the lens frame 200.
[0029]
Then, the X stage 320 is driven to move the operation lever 310 in the front-rear direction. When the operation lever 310 is moved forward, the projection 314 on the front side of the operation lever 310 abuts on the front end surface 204a of the slit portion 204 and urges it forward. When the operation lever 310 is moved rearward, the protruding portion 316 on the rear side of the operation lever 310 abuts on the rear end surface 204b of the slit portion 204 and urges it backward.
[0030]
In the first embodiment, the point of action where the protrusions 314 and 316 of the operation lever 310 apply a force to the lens frame 200 is parallel to the moving direction of the lens frame 200 and passes through the center of gravity P of the lens frame 200 (A Surface). That is, since the center of gravity P is on the line of action of the force applied to the lens frame 200 from the protrusions 314 and 316 of the operation lever 310, a moment that tilts the lens frame 200 in the vertical plane does not occur.
[0031]
In addition, the action point at which the protruding portions 314 and 316 of the operation lever 310 apply force to the lens frame 200 is substantially located on a surface (B surface) orthogonal to the moving direction of the lens frame 200 and including the center of gravity P of the lens frame 200. is doing. Further, the two protruding portions 314 and 314 (or the protruding portions 316 and 316) are arranged substantially symmetrically with respect to the center of gravity P of the lens frame. Therefore, a moment that tilts the lens frame 200 in the horizontal plane does not occur.
[0032]
As described above, according to the first embodiment, it is possible to adjust the position without tilting the lens frame.
[0033]
Next, a second embodiment of the present invention will be described.
FIG. 8 shows the position adjusting device 400 and the lens frame 200 of the second embodiment. The position adjusting device 400 according to the second embodiment includes a swing mechanism 420 (instead of the X stage). The structures of the operation lever 310 and the lens frame 200 are exactly the same as in the first embodiment.
[0034]
The Z stage 430 of the position adjusting device 400 includes a fixed portion 432 and a slider 434 that can move up and down with respect to the fixed portion 432. An operation lever 310 is swingably supported on a stay 435 formed integrally with the slider 434. A micrometer 440 is attached to the stay 435, and a tip portion 442 of the micrometer 440 is in contact with the upper end of the operation lever 310. Further, a spring 444 is provided on the side opposite to the micrometer 440 across the operation lever 310. The spring 444 presses and biases the operation lever 310 against the micrometer 440.
[0035]
When adjusting the position of the lens frame 200, first, the Z stage 430 is driven to engage the tip portion 312 with the slit portion 204 of the lens frame 200. In this state, the operation lever 310 faces the vertical direction. At this time, the protrusions 314 and 316 are set to the same height as the center of gravity of the lens frame 200.
[0036]
Then, the micrometer 440 is driven to swing the operation lever 310 as shown in FIG. When the operation lever 310 is swung clockwise, the projecting portion 314 comes into contact with the front end surface 204a of the slit portion 204 and biases it forward. When the operation lever 310 is swung counterclockwise, the projecting portion 316 comes into contact with the rear end surface 204b of the slit portion 204 and biases it backward.
[0037]
Also in the second embodiment, the action point at which the protrusions 314 and 316 of the operation lever 310 apply a force to the lens frame 200 is a plane parallel to the moving direction of the lens frame 200 and passing through the center of gravity P of the lens frame 200 (A Surface). Further, the amount of vertical movement of this action point (with the swing of the operating lever 310) is small. Therefore, a moment for rotating the lens frame 200 in the vertical plane is not generated.
[0038]
In addition, the action point at which the protruding portions 314 and 316 of the operation lever 310 apply force to the lens frame 200 is substantially located on a surface (B surface) orthogonal to the moving direction of the lens frame 200 and including the center of gravity P of the lens frame 200. The two protrusions 314 and 314 (or the protrusions 316 and 316) are arranged substantially symmetrically with respect to the center of gravity P of the lens frame. Therefore, a moment that tilts the lens frame 200 in the horizontal plane does not occur.
[0039]
As described above, according to the second embodiment, as in the first embodiment, it is possible to adjust the position without tilting the lens frame.
[0040]
The present invention can be applied not only to the adjustment of the collimating lens described in the first and second embodiments, but also to fine adjustment in the optical axis direction of a widely used lens frame.
[0041]
【The invention's effect】
As described above, according to the lens frame position adjusting method and position adjusting apparatus of the present invention, it is possible to adjust the position without tilting the lens frame.
[Brief description of the drawings]
FIG. 1 is a diagram showing a basic configuration of a magneto-optical disk apparatus according to an embodiment.
2 is a view showing a tip end portion of a rotating arm of the magneto-optical disk apparatus of FIG. 1. FIG.
FIG. 3 is a cross-sectional view showing a floating optical unit.
FIG. 4 is a plan view showing a configuration of a rotating arm.
5 is a side view of the rotating arm of FIG. 4. FIG.
FIGS. 6A and 6B are a front view and a side view showing the adjusting device. FIGS.
7 is a diagram showing an adjustment process by the adjustment device of FIG. 6; FIG.
FIG. 8 is a side view showing an adjusting device according to a second embodiment.
FIG. 9 is a side view showing an adjusting device according to a second embodiment.
FIG. 10 is a schematic view showing a conventional position adjustment method.
[Explanation of symbols]
20 Collimating lens 100 Base 102 Abutting surface 200 Lens frame 204 Slotting section 300 Adjusting device 310 Operation lever 312 Tip section 314, 316 Projection section 320 X stage 330 Z stage

Claims (12)

A position adjustment method for moving a lens frame in a predetermined direction and adjusting its position,
Nearly located on an intersection line between a plane parallel to the predetermined direction and including the approximate center of gravity of the lens frame and a plane perpendicular to the predetermined direction and including the approximate center of gravity of the lens frame Applying force to the lens frame at two points
A lens frame position adjustment method characterized by the above. The lens frame position adjusting method according to claim 1, wherein the two points are substantially symmetric with respect to the center of gravity of the lens frame. Using an operation member extending perpendicularly to the predetermined direction and having two contact portions corresponding to the two points;
The lens frame position adjusting method according to claim 1, wherein the lens frame position is adjusted. The operating member has a bifurcated tip;
4. The lens frame position adjusting method according to claim 3, wherein the tip end portion engages with two slit portions formed on the lens frame. The lens frame position adjusting method according to claim 4, wherein the operation member is linearly moved in the predetermined direction. 5. The lens frame position adjusting method according to claim 4, wherein the operation member is swung around a predetermined swing axis. A position adjustment device that moves a lens frame along a predetermined direction and adjusts its position,
An operation member that moves the lens frame by applying force;
The position where the operating member applies force to the lens frame is parallel to the predetermined direction and includes a surface including the approximate center of gravity of the lens frame, and is perpendicular to the predetermined direction and approximately the lens frame. 2 points that are almost located on the intersection line with the plane including the center of gravity,
A lens frame position adjusting device characterized by the above. The lens frame position adjusting device according to claim 7, wherein the two points are substantially symmetric with respect to the center of gravity of the lens frame. The operating member extends perpendicular to the predetermined direction;
The operation member has two contact portions corresponding to the two points;
The lens frame position adjusting device according to claim 7 or 8. The operating member has a bifurcated tip;
The lens frame position adjusting device according to any one of claims 7 to 9, wherein each of the front end portions engages with two slit portions formed on the lens frame. The lens frame position adjusting device according to claim 7, wherein the operation member is configured to move straight in the predetermined direction. The lens frame position adjusting device according to claim 7, wherein the operation member is configured to be swingable about a predetermined swing shaft.

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