JP3715643B2 - Guide shaft adjustment method - Google Patents

Description

  The present invention relates to a guide shaft adjusting method for adjusting a guide shaft that movably supports a pickup head, for example, in an optical disc apparatus.

  As shown in FIG. 15, in an optical disk reproducing apparatus conventionally used, an optical disk (for example, CD) 1 is rotationally driven by a spindle motor (not shown) as a driving source with a rotation center O as a fulcrum. At this time, a signal recorded as concentric or spiral minute pits on the optical disc 1 is reflected by the laser light emitted from the pickup head 2 reflected by the optical disc 1 and received by the pickup head 2 again. It can be read.

  The pickup head 2 is installed between a first guide shaft 4a and a second guide shaft 4b provided on the mechanical chassis 3 and parallel to each other. The pickup head 2 is driven to move along the axial direction R. The Therefore, the locus of the emission point P of the laser beam when the pickup head 2 is moved in the R direction is a straight line, and the extension line thereof coincides with the rotation center O of the disk 1.

  The positional relationship between the optical disc 1 and the pickup head 2 can be easily understood with reference to FIG. Here, a spindle motor 5 as a drive source for rotationally driving the disk 1 is also shown. The most important point in the accuracy of the positional relationship between the disk 1 and the pickup head 2 is a coordinate space consisting of Z, R, and T orthogonal coordinate systems, and the optical axis of the laser beam emitted from the pickup head 2 and the disk 1. And the optical axis and the Z axis which is the central axis of the disk 1 must be parallel to each other.

  If the optical axis of the laser beam emitted from the pickup head 2 is tilted, the light reflected by the disk 1 cannot be correctly returned to the emission point P of the pickup head 2, leading to a reading error and a decrease in S / N. When the tilt of the optical axis is decomposed into components of an RZ plane and a TZ plane, they are called a radial inclination θr and a tangential inclination θt, respectively. These inclinations are important conditions that influence the performance of the optical disk reproducing apparatus, and the limits of these values differ depending on various formats of the disk. In the case of the above optical disk reproducing apparatus, since the allowable tilt value of the optical axis is large, each component such as the spindle motor 5 for rotationally driving the pickup head 2 and the disk 1 and the first and second guide shafts 4a and 4b. I should have managed the accuracy of each.

  However, with the recent demand for higher density, optical disks recorded with higher density have been standardized (DVD). This optical disc has a capacity of 5 GB on one side, and a signal is recorded at a density 7 times or more that of a currently used CD, and can store a moving image encoded with a predetermined compressed signal. For this reason, the accuracy of mechanical requirements for the playback / recording mechanism has become much stricter, such as the track pitch of the disc being 1.6 μm of CD to 0.74 μm which is half of that of an optical disc.

  Therefore, in an optical disk reproducing / recording apparatus that reproduces and records an optical disk, the relative angle between the optical axis of the pickup head and the optical disk cannot fall within an allowable inclination only by managing the accuracy of individual components as in the conventional optical disk apparatus. The problem is emerging. Therefore, for example, for an optical disk reproducing / recording apparatus, there is a demand for development of a means for adjusting the relative angle between the optical axis of the pickup head and the optical disk reasonably at low cost. Satisfying this requirement applies to all devices that ensure the accuracy of movement of the moving body with respect to the reference surface, instead of the moving body that moves the optical disk in place of the reference surface and the pickup head in parallel with the reference surface. It will be possible.

  The present invention has been made paying attention to the above circumstances, and the object of the present invention is to provide a guide shaft that facilitates adjustment by simplifying parameters during adjustment by using an adjustment member having one degree of freedom. It is intended to provide an adjustment method.

In order to achieve the above object, the present invention provides a twist as seen from the direction following the reference plane of a plurality of guide shafts held parallel to the reference plane, which is parallel to the reference plane, which guides a moving body that moves parallel to the reference plane. Alternatively, in the guide shaft adjustment method of adjusting the adjustment member that can be continuously changed by rotating the orientation of the bearing portion receiving the guide around the radial direction as an axis,
A first step of measuring the position of the bearing portion or the guide shaft on the bearing portion with respect to the reference surface, and rotating the adjustment members at both ends of the guide shaft to be adjusted based on at least the data of the first step, thereby rotating the reference surface A second step of adjusting the distance in the radial direction of the guide shaft to be adjusted to be the same as that of the reference guide shaft, one end of the guide shaft to be adjusted and a reference guide based on at least the first step data And a third step of rotating the adjusting member receiving one end of the shaft to adjust the direction of each of the plurality of guide shafts in parallel with the reference plane.

  A movable body that can move along the guide axis with respect to the reference surface is provided, and the relative angle of the movable body with respect to the reference body is within an allowable inclination, and the movement accuracy of the movable body is improved by rational adjustment. A guide shaft adjusting method can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, as an optical disc apparatus, an optical disc 10 is rotationally driven by a spindle motor M as a drive source with a rotation center O as a fulcrum. That is, the optical disk 10 is driven to rotate but serves as a reference plane. A pickup head 11 that emits a laser beam to the optical disk 10 is supported via a base B that is a parallel holding portion provided between a first guide shaft 12a and a second guide shaft 12b that are parallel to each other. Has been.

  The pickup head 11 includes a drive source (not shown), and is driven to move along the axial direction R of each guide shaft 12a, 12b. That is, the pickup head 11 and the base B correspond to a moving body that moves relative to the optical disk 10 as a reference surface. The portion of the base B that engages with the second guide shaft 12b is made of oil-impregnated metal and has a very slight gap fit, whereas the portion that engages with the first guide shaft 12a is Z, Only the movement in the Z direction of the R and T spaces is restricted.

  The optical disk 10 has concentric or spiral pit rows with minute irregularities, and the pickup head 11 irradiates a laser beam to the optical disk that is driven to rotate, and receives the reflected light to generate a signal. Is read. The locus of the laser light emission point P when the pickup head 11 is moved in the R direction is a straight line, and the extended line thereof coincides with the rotation center O of the optical disk 10.

With such a basic configuration, the first and second guide shafts 12 a and 12 b for guiding the pickup head 11 are supported by a guide shaft adjusting device 14, which will be described later, provided on the mechanical chassis 13.
The guide shaft adjusting device 14 includes a first adjusting member 15a and a second adjusting member 15b that support both end portions of the first guide shaft 12a, and a first supporting member that supports both end portions of the second guide shaft 12b. 3 adjustment members 15c and receiving members 15d. As shown in FIG. 3, the first to third adjustment members 15 a to 15 c include a rotating member 16 that is integrally formed with the mechanical chassis 13 by outsert molding, and a flange surface on the upper surface side of the rotating member. And a cam 17 as a bearing portion projecting from the head.

  Since the rotating member 16 is outsert-molded, it is constrained to a range in which it does not rotate unless there is a rotational moment from the outside. The rotating member 16 is provided so as to be rotatable with respect to the mechanical chassis 13 and is restricted from being extracted from the mechanical chassis. A hexagonal hole 16a is provided in the central axis of rotation.

  The cam 17 protrudes from the flange surface of the rotating member 16 and is formed so that the height dimension gradually changes according to the rotation angle of the rotating member 16. That is, the cam 17 is provided with an inclination along the circumferential direction with respect to the rotation center of the rotating member 16. Since the end portions of the first and second guide shafts 12a and 12b are placed on the upper end surface of the cam 17, the upper end surface of the cam 17 becomes a bearing surface. The receiving member 15d receives and supports the end portion of the second guide shaft 12b.

  As shown only in FIG. 1, the end portions of the guide shafts 12 a and 12 b near the first to third adjustment members 15 a to 15 c are elastically pressed and urged by a pressing spring 18 provided on the mechanical chassis 13. The The portions near the ends of the guide shafts 12 a and 12 b are engaged with a U metal fitting 19 provided on the mechanical chassis 13, and the end surfaces are in contact with the peripheral surface of the rotating member 16. Accordingly, the guide shafts 12a and 12b are restricted from moving in the T direction by the U metal fitting 19, and their end surfaces are in contact with the rotating member 16 to restrict movement in the axial direction.

  Each of the guide shafts 12a and 12b is guided by the U metal fitting 19 and can move up against the elastic force of the presser spring 18, and is a displacement that moves downward by being pressed by the presser spring. Can move freely. If the bit 20 having the same shape and size is inserted and engaged in the hexagonal hole 16a of the rotating member 16, the pulse motor 21 as a driving source of the bit is driven to rotate the rotating member 16 in the circumferential direction K. The guide shaft support portion of the cam 17 changes, and the guide shafts 12a and 12b are moved in the Z direction. It should be noted that the cams 17 provided on the first to third adjustment members 15a to 15c have the same ratio of change in height dimension with respect to the rotation angle of the rotation member 16.

In such a guide shaft adjusting device 14, the first to third adjusting members 15a to 15c are attached to the mechanical chassis 13 as follows.
That is, as shown in FIG. 2, the support point of the third adjusting member 15c with respect to one end portion of the second guide shaft 12b is set at a distance L1 from the rotation center O of the optical disk 10. The support points of the first and second adjustment members 15a and 15b with respect to both end portions of the first guide shaft 12a are located at a distance L2 passing through the rotation center O of the optical disk 10 from the support point of the third adjustment member 15c. Set. Then, the support points of the second and third adjusting members 15b and 15c are set at a distance L3 from the rotation center O of the optical disk 10.

  Therefore, a line segment a1 -a2 connecting the guide shaft support points of the first adjustment member 15a and the second adjustment member 15b and a line connecting the guide shaft support points of the second adjustment member 15b and the third adjustment member 15c. It is orthogonal to the minute b1 -b2. An extension line c1 -c2 of the locus of the emission point P of the pickup head 11 when the pickup head 11 is moved in the R direction along the first and second guide shafts 12a and 12b is the optical disk 11 Are arranged so as to coincide with the rotation center O of the.

  Since the first and second guide shafts 12a and 12b are thus supported by the guide shaft adjusting device 14, the bit 20 is fitted into the hexagonal holes 16a of the adjusting members 15a to 15c and rotated. Thus, the height of the guide shaft end can be arbitrarily adjusted. And since each adjustment member 15a-15c is the completely same shape and the length to a support point is the same, the ratio of the height position change of the guide shaft support point with respect to the rotation angle of each adjustment member is the same. .

  In other words, first, the first and second guide shafts 12a and 12b are not twisted by displacing the second adjustment member 15b and the third adjustment member 15c in the Z direction in FIG. The state, that is, the two guide shafts can exist on the same plane. Next, the first adjusting member 15a and the second adjusting member 15b are simultaneously displaced in the Z direction in FIG. 3 by the same amount, so that the two guide shafts exist on the same plane first. The pickup head 11 can be tilted in the tangential tilt θt direction shown in FIG.

  As described above, since the shapes of the cams 17 provided on the first adjustment member 15a and the second adjustment member 15b are the same, the ratio of the change in position of the guide shaft support point with respect to the rotation angle of each adjustment member. Are the same. At this time, the flatness of the mechanical chassis 13 in which the guide shafts 12 a and 12 b are arranged via the guide shaft adjusting device 14, the inclination of the spindle motor that is a drive source when the optical disk 10 is rotated, the pickup head 11 Since it can be estimated that the sum of the inclination of the optical axis and each guide shaft is at least ± 0.4 ° in terms of the relative angle between the optical axis and the optical disc, the shape of the cam 17 of each of the adjustment members 15 a to 15 c is the same as that of the optical disc 10. The shape is such that the relative angle with respect to the pickup head 11 can be adjusted to 0.8 ° or more.

  That is, the distance L4 between the support points of the first adjustment member 15a and the second adjustment member 15b (this is equal to the distance between the third adjustment member 15c and the support portion 15d), and the flange surface of the cam 17 The relationship from the height to the highest point (adjustable height) t is arctan (t / L4)> 0.8 [deg].

  As shown in FIG. 4A, in the embodiment described above, the segment connecting the first and second guide shafts 12a and 12b is parallel to the optical disc 1 serving as the reference plane. The base B as a moving body was set so as to be. However, the present invention is not limited to this, and as shown in FIG. 5B, the second guide shaft 12b is positioned above the first guide shaft 12a, and each central axis is a reference plane. An optical pickup head 11A may be mounted on a base B1 that has an acute angle with respect to an optical disk 1. Further, as shown in FIG. 3C, the base B2 is such that the line segment connecting the central axes of the first guide shaft 12a and the second guide shaft 12b is perpendicular to the optical disc 1 serving as the reference plane. An optical pickup head 11B may be mounted.

  Here, the relative angle adjustment between the optical disk 10 and the pickup head 11 will be described in detail. The relative angle between the optical disk 10 and the pickup head 11 is adjusted by minimizing a jitter (time axis error) value generated when the pickup head 11 reads a signal on the optical disk 10. This is because there is a correlation as shown in FIG. 5 between the relative angle between the optical disc 10 and the pickup head 11 and the jitter value.

  The plot in the figure shows the relationship between the pickup head tilt obtained by measurement and the jitter value of the 3T signal, and the curve is approximated to a quadratic function using the least square method based on these data. It is. The angle error on the horizontal axis indicates the inclination of the optical axis with respect to the optical disc, and an angle of 0 ° means that the laser beam is irradiated at a right angle to the optical disc. In an actual device manufacturing process, adjusting this angle to 0 ° (minimizing the jitter value) is almost impossible not only from the viewpoint of productivity but also from the technical aspect. Therefore, when the margin of this angle was calculated in consideration of various factors such as warpage and surface runout of the optical disk, it was necessary to adjust the margin to be within ± 0.1 °.

  However, in the target range of ± 0.1 °, the characteristics are very flat and it is difficult to judge the quality, and it takes time and effort to find the best jitter value by trial and error. It is a problem. Simulation must be applied to obtain an optimal solution to the problem of how many points the data is sampled in consideration of various conditions. When sampling is performed at three points, assuming that the function of FIG. 6 shows a true characteristic, there is a measurement error in the values obtained at each sampling point, and thus the acquired data is stored in sets j1, j2, and j3. To be distributed.

  The distribution state at this time can be assumed to be a normal distribution centered on the true values J1, J2, and J3. It can be easily imagined that the minimum value taken by the quadratic function determined by three points selected by chance from the respective data sets j1, j2, and j3 according to the normal distribution function also varies. In this simulation, random numbers were generated to create a set of data according to the normal distribution, and data was randomly extracted from each set to perform function approximation. Finally, the number of sampling points and the range may be obtained so that the variation of the minimum points is within the target adjustment accuracy ± 0.1 °.

In carrying out the simulation, the following conditions were taken into consideration in consideration of the DVD standard, actual jitter value measurement problems, pickup head accuracy variation, adjustment range of the guide shaft adjustment mechanism, and the like.
a) Data whose jitter value exceeds 15% is deleted from the data because the reliability of the value becomes low.
b) The standard of tilt accuracy of the pickup head is ± 0.3 ° in the radial direction and ± 0.2 ° in the tangential direction.
c) The adjustment range of the adjustment mechanism is 0.8 °. That is, since it can be estimated that the relative angle between the optical axis and the optical disc is at least ± 0.4 ° or more, the adjustment member needs to be shaped so that the relative angle between the optical axis and the optical disc can be adjusted to 0.8 ° or more. It is. The number of samplings was 10K-100K.

  Hereinafter, an angle adjustment sequence for the first and second guide shafts 12a and 12b will be described in detail. In other words, the sequence of angle adjustment is in the order of parallelism of the two guide shafts-radial inclination θr adjustment-tangential inclination θt adjustment. A line segment c1 -c2 formed by the locus of the emission point P of the laser beam when the optical disk 10 is moved in the radial direction is defined only by the second guide shaft 12b. Therefore, the parallelism of the two axes in this sequence is performed in order to fit the two axes on the same plane. If the two axes are not on the same plane, that is, in a twisted relationship, even if the optical axis and the optical disk plane are adjusted at a right angle at a specific point on the optical disk 10, the pickup head 11 is moved in the radial direction. When it is moved, a tangential gradient θt is generated.

The concept of this biaxial parallelism will be described with reference to FIGS. Note that the positions of the first and second guide shafts 12a and 12b in the figure are shown opposite to the left and right positions of the first and second guide shafts 12a and 12b in FIGS.
First, the twist adjustment will be described. As shown in FIG. 7A, the first guide shaft 12a that is not parallel to a certain plane M0 is subjected to a sequence in which twisting is eliminated as shown in FIG. The cam 17 of the first adjusting member is rotated to give displacement to the first guide shaft 12a. At this time, if the two axes are located on the same plane M0, the parallelism of the two axes may not be a problem.

  Next, radial adjustment will be described. This radial tilt adjustment is performed by adjusting only the θr component in the coordinate system shown in FIG. Conceptually, it is as shown in FIG. 8. From the state of FIG. 8A, the cam 17 of the second and third adjusting members 15b and 15c is rotated in operation to displace the two axes. The plane M0 formed by the axis is inclined to be a new plane M1. At this time, it is necessary to make the displacement amounts of the shafts by the respective cams 17 the same so that the parallel relationship described above is lost and the two shafts are not twisted.

  Next, tangential adjustment will be described. In the coordinate system shown in FIG. 16, the tangential tilt adjustment is performed by adjusting only the θt component. Conceptually, as shown in FIG. 9, the cams 17 of the first adjustment member 15a and the second adjustment member 15b are rotated to give displacement to the first guide shaft 12a, and the plane M1 up to that point is changed. Tilt to a new plane M2. At this time as well, as in the radial adjustment described above, it is necessary to make the amount of displacement of the shafts by the respective cams 17 the same so that the two shafts are not twisted.

  In order to automatically execute such adjustment, it is necessary to monitor the relative angle between the optical disc 10 and the pickup head 11 by some method. That is, in the parallel alignment sequence of the two guide shafts, the twist of the first guide shaft 12a is adjusted to the second guide shaft 12b while the Z coordinate is monitored by a linear gauge having a resolution of 1 μm to eliminate the twist. The points to be measured with the linear gauge are shown in FIG. 7 (A). While rotating the cam at four points LP1 to LP4, the Z coordinates of the four points are dynamically measured, and the Z coordinates of LP1 and LP2 are measured. The twist of the first guide shaft 12a and the second guide shaft 12b is eliminated by making the difference coincide with the difference between the Z coordinates of LP3 and LP4.

  In the sequence of the radial tilt θr adjustment and the tangential tilt θt adjustment, the sequence is executed using the jitter value of the signal when the optical disk 10 is reproduced by the pickup head 11. This is because, as described above, the jitter value and the relative angle between the optical disc 10 and the pickup head 11 have a relation that can be approximated by a quadratic function. At this time, since the jitter value is minimized when θr and θt are 90 °, the cam 17 may be adjusted so that the jitter value is minimized in each sequence of the radial gradient θr and the tangential gradient θt.

  The actual sequence of the automatic adjuster will be described with reference to the flowchart of FIG. The overall sequence can be broadly divided into an adjustment process and an inspection process. Steps 1 to 6 are adjustment processes, and subsequent steps 7 to 11 are inspection processes. In the first cassette, the mechanical unit to be adjusted is clamped to the adjusting machine, and the electrical circuit is connected. In the bit set of Step 2, the bit 20 of the stepping motor 21 is inserted into the hexagonal hole 16a of the rotating member 16 in order to rotationally drive the cams 17 of the adjusting members 15a to 15c.

  In the biaxial parallelism in step 3, the adjusting member is rotated to adjust the support height with respect to the cam shaft, and the twist of the two shafts is eliminated. In the DVD disk set in Step 4, a DVD standard test optical disk is set, and a play operation (reproduction) is started. In the radial adjustment in step 5, the second and third adjustment members 15b and 15c are rotated by the same amount, and the plane formed by the two axes is inclined in the radial direction. In the tangential adjustment in step 6, the planes formed by the two axes are inclined in the tangential direction by rotating the first and second adjustment members 15a and 15b by the same amount. The above is the adjustment process.

  In the register determination in step 7, the parameter value stored in the register of the servo microcomputer is taken into the personal computer and the determination is made. In the measurement in step 8, the RF output and the laser current are measured with a multimeter. While controlling the selector switch with GP-IB, the multimeter value is transferred to the personal computer with GP-IB. In the DVD-CD conversion in step 9, the play state is lowered and the DVD disc is removed. Next, a test disk of a CD disk is mounted and a play state is started. In the measurement in step 10, the jitter value on the CD disk is measured. Since the measurement condition of the jitter value at this time is different from that of the DVD, the measuring instrument is initialized (initialized) for the CD in advance. In step 11, the play is stopped and the CD disc is stored. The bit 20 engaged with the hexagonal hole 16a is reset, the battle between the mechanism and the servo circuit is removed, the clamp is released, the mechanism is removed from the adjusting machine, and the process ends.

  Below are the details of the main adjustment algorithms. First, the bit set adjustment algorithm described in step 2 will be described in detail. That is, the hexagonal holes 16b of the adjusting members 15a to 15c having the cams 17 paired with the bit 20 have backlash. Making this backlash mechanically and extremely small leads to the occurrence of errors in the bit set and the addition of stress that cannot be ignored on the mechanical chassis 13, thereby reducing the reliability of adjustment.

  Here, the above problem of backlash was dealt with by an algorithm. As shown in FIG. 11A, the relationship between the Z coordinate displacement of the corresponding guide shafts 12a and 12b when the cam 17 is rotated and the rotation angle of the cam 17 is defined. Next, the relationship between the rotation angle of the bit 20 and the Z coordinate displacement of the guide shafts 12a and 12b is shown in FIG. This figure shows a case where the bit is rotated to + 180 ° and then reversed to return to 0 °. However, hysteresis for backlash occurs. As a countermeasure, the cam 17 positioning algorithm is performed as shown in FIG. In other words, when the cam 17 and the bit 20 are rotated from 0 ° and reversed when the cam 17 and the bit 20 are at 180 ° to return the cam to 0 °, as shown by the broken line in FIG. The amount obtained by adding the stroke is rotated in the minus direction, and the overstroke is further rotated in the plus direction to absorb backlash.

  Therefore, in the algorithm for turning the cam 17, in all cases where the rotation of the cam 17 is stopped, it is unified in either the positive direction or the negative direction. The problem of backlash is basically solved by rotating the motor and then stopping it after correcting for the overstroke. In the actual bit setting process, as described above, the phases of the bit 20 and the cam 17 are matched. However, in order to absorb backlash, the bit 20 is rotated once in the minus direction and then returned to the plus direction and stopped. The algorithm is set.

  Next, the biaxial parallelism algorithm described in step 3 will be described in detail. As shown in the flowchart of the algorithm of FIG. 12, the twist of the two axes is eliminated while measuring the Z coordinates of the first guide shaft 12a and the second guide shaft 12b with a linear gauge. That is, the linear gauge is first lowered, and the linear gauge is set at four points (LP1 to LP4 in FIG. 6) on both ends of the first and second guide shafts 12a and 12b. At this time, the completion of descent of the linear gauge is monitored by the position sensor of the linear gage, and an error during descent is monitored.

  Next, the set linear gauge values (LP1 to LP4) are read by a personal computer, and the two-axis state is judged by comparing the difference between LP1 and LP2 and the difference between LP3 and LP4. At this time, if the difference between LP1 and LP2 is within ± 5 μm, it is assumed that the parallel adjustment has been completed, the linear gauge is raised, and the parallel adjustment sequence ends. If the difference between the two is ± 5 μm or more, it is determined that the two axes are in a torsional relationship, and the bit 20 that rotationally drives the cam 17 of the first adjusting member 15a is activated to change the coordinates of LP2. Let

  After starting the bit 20, if the rotation direction of the spindle motor 21 is positive, the difference between LP1 and LP2 and the difference between LP3 and LP4 are dynamically performed in the DO loop, and the difference between the two is within ± 5 μm. Stop the motor. If the spindle motor 21 is rotated in the minus direction, LP1 and LP2 while passing the stop position, rotating once for the overstroke, rotating in the reverse direction, and rotating to the plus side to prevent backlash as described above. Stop when the difference between LP3 and LP4 is within ± 5μm. In this way, the biaxial parallel adjustment is completed, the linear gauge is raised, and the parallel adjustment sequence is completed.

  Next, the radial adjustment algorithm described in step 5 will be described in detail. As shown in the flowchart of the algorithm in FIG. 13, the basic of radial adjustment is driven with cam A (cam 17 of third adjusting member 15c) and cam B (cam 17 of second adjusting member 15b) as a set. It is to be. This is because the plane formed by the two axes of the first and second guide shafts 12a and 12b is not broken as described above.

  The manner of rotating the cam is shown in FIG. 14 and will be described together with the float of FIG. That is, FIG. 14 shows the cam position at the point where the guide shaft is supported, and shows the trajectory when set at the specified position. Specifically, the case where the cam 17 is sent to P0 from the start will be described. At the start position, the guide shafts 12a and 12b are supported at the approximate center of the cam 17. This is because the rotating member 16 integrated with the cam 17 is outsert formed in the mechanical chassis 13, so that the cam is in this position before the adjustment, that is, when the cam 17 is not rotated.

  Next, the cam 17 is sent so that the shaft is supported at the point P0 closest to 0 °. As described above, since the rotation direction of the spindle motor 21 is negative, the cam 17 is overloaded to absorb backlash. Reverse the stroke and stop. Here, the jitter value at point P0 is captured by GP-IB, and the cam 17 is rotated to measure the jitter values at points P1 to P5. At this time, since the approximation is performed by the method of least squares, the intervals of P0 to P5 are made equal.

  When six points of data are taken in as described above, a quadratic approximate curve is determined from these data, and an inflection point (minimum point) is obtained. Since the obtained minimum point is the best point of the jitter value, the cam 17 is finally rotated to match the calculated best point, and the estimated jitter value obtained by the calculation is compared with the jitter value of the best point. The radial adjustment is complete when the discrepancy increases.

  Next, the algorithm for the tangential adjustment described in step 6 will be described in detail. This is basically the same as radial adjustment. However, as in the flowchart shown in FIG. 13, in the radial adjustment, the inclination is adjusted by the cam A and the cam B, but in the tangential adjustment, the cam B (the cam 17 of the second adjustment member 15b) and the cam C ( The cam 17) of the first adjusting member 15a is used.

  In addition, the jitter value changes more sensitively to the inclination θt in the tangential direction of the pickup head 11 than the inclination θr in the radial direction, so that the jitter value measurement pitch is made smaller than the radial adjustment. Since the concept of eliminating the backlash is the same as the radial adjustment, the cam drive is basically performed as shown in FIG. However, in the radial adjustment, it has been explained that the start point of the cam 17 is almost in the center (180 °). However, in the tangential adjustment, the cam 17 has already been rotated during the radial adjustment (the best point of the radial). In addition, since the cam C is rotated during the parallel adjustment, the start point of the cam is not determined.

  However, the cam position after radial adjustment falls within ± 60 ° from the center (180 °) from the pick-up head standard, chassis flatness standard, disk motor standard, etc., so there is no problem. Similar to the radial adjustment at the end of the flowchart, the estimated jitter value obtained by calculation is compared with the jitter value at the best point, and if the difference is not large, the tangential adjustment is completed.

  As described above, by using the optical disk device and the guide shaft adjusting method, by using the adjusting member having one degree of freedom, the parameters at the time of adjustment can be simplified and the adjustment becomes easy. That is, since the change in the height of the cam 17 of the adjustment members 15a to 15c corresponds to the change in the angle of the adjustment member on a one-to-one basis, if the reference plane by the optical disc 1 is input to the control unit of the adjustment device in advance, The distance relationship between the reference plane and the guide shaft can be managed using only the rotation angle of the adjustment member as a parameter. Therefore, if the height from the reference surface of each bearing part of each adjustment member 15a-15c is monitored using a linear gauge etc., adjustment can be completed only by rotation angle management.

  Further, since the rotation axis is set in a direction perpendicular to the optical disc 1, it is easy to adjust the device constituting the optical pickup unit while being mounted on the optical disc device. In the above embodiment, the optical disk device has been described. However, the movable body is movable along the guide axis with respect to the reference plane, and the relative angle of the movable body with respect to the reference plane is within an allowable inclination. The method can be applied to all guide shaft adjustment methods capable of improving the moving accuracy of the moving body by rational adjustment.

1 is a schematic perspective view of an optical disc apparatus according to an embodiment of the present invention. 1 is a schematic plan view of an optical disc device. The perspective view of a guide shaft adjustment apparatus. (A), (B), (C) is a figure explaining the mutually different parallel form of a guide shaft. The characteristic figure of the jitter value with respect to a pickup head inclination. The characteristic figure of the jitter value with respect to the angle error of a pickup head. (A), (B) is a conceptual diagram of the parallel adjustment with respect to the 1st, 2nd guide shaft. (A), (B) is a conceptual diagram of the radial adjustment with respect to the 1st, 2nd guide shaft. (A), (B) is a conceptual diagram of the tangential adjustment with respect to the 1st, 2nd guide shaft. The flowchart figure of an automatic adjustment machine operation | movement sequence. (A)-(C) is a figure explaining positioning of the bit set in an adjustment algorithm. The flowchart figure showing the algorithm of biaxial parallel adjustment. The flowchart figure showing the algorithm of radial adjustment. Cam feed conceptual diagram. FIG. 2 is a schematic plan view of a conventional optical disc apparatus. The perspective view explaining the spatial coordinate system of an optical disc device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Optical disk (reference surface), 11 ... Pick-up head (moving body), 2a ... 1st guide shaft, 12b ... 2nd guide shaft, B ... Parallel holding member (base), 15a ... 1st adjustment member, 15b ... 2nd adjustment member, 15c ... 3rd adjustment member, 17 ... Bearing part (cam).

Claims (1)

The plurality of guide shafts held parallel to the reference plane that guides the moving body that moves parallel to the reference plane are twisted or oriented as viewed from the direction following the reference plane. In the guide shaft adjustment method of adjusting the adjustment member that can be continuously changed by rotating the height of the bearing portion that is pivoted around the radial direction,
A first step of measuring the position of the bearing portion or the guide shaft on the bearing portion with respect to a reference plane;
A guide shaft based on the distance in the radial direction of the guide shaft to be adjusted relative to the reference plane by rotating the adjusting members at both ends of the guide shaft to be adjusted based on at least the data of the first step; A second step of adjusting the same,
The adjustment member receiving one end of the guide shaft to be adjusted and one end of the reference guide shaft is rotated based on at least the first process data, and each direction of the plurality of guide shafts is changed to the direction of the guide shaft. And a third step of adjusting in parallel with the reference plane.

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