JPH038123A - Pickup position adjusting device - Google Patents

Abstract

PURPOSE:To make both of an inclination and an interval of an optical pickup to a disk constant even in the case there is a deflection or a camber in the disk by driving an inclination adjusting means and a height adjusting means by each driving means. CONSTITUTION:When an interval between a disk 1 and an optical pickup PU 5 becomes large, an error signal is inputted to a height adjustment driving circuit 27, and a height adjusting motor 26 is driven. When the motor 26 rotates, an arm supporting member 24 descends by a height adjusting screw 25, and a rotary arm 22 turns clockwise centering around an arm turning supporting point 23. When the arm 22 turns, a height adjusting member 21 turns clockwise centering around a pin 21a by a pin 21b erected vertically thereon, the PU 5 is moved in the direction for approaching the disk 1, and an interval between the disk 1 and the PU 5 becomes small. In such a way, the interval between the disk 1 and the PU 5 can be made constant.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a pickup position adjustment device for an optical disk device that records and reproduces information on a disk.

2. Description of the Related Art In general, currently used video optical discs have information engraved in a spiral shape on the disc in the form of concavities and convexities with a width of 0.4 μm and a length of 0.5 to 1.8 μm.

To read this information, a laser beam is focused on a minute spot with a diameter of 1 μm through an objective lens, and the reflected light is guided to a light receiving element through the objective lens again and extracted as an electrical signal. By the way, since the discs used as optical discs for video are made of PMMA resin with a diameter of 3Qcm, there is warpage due to temperature, humidity, or distortion during molding. Because it is clamped and rotated, it also deflects due to its own weight. When reproducing such a disc with an optical pickup, unless the laser beam is irradiated perpendicularly to the disc, the beam spot diameter will increase and the S/N of the reproduced signal will deteriorate. To correct this, the relative positional relationship between the optical pickup and the disk, that is, the inclination between the incident direction of the laser beam and the disk, is detected, and the optical pickup is tilted according to the amount of inclination so that the laser beam is irradiated vertically. A so-called tilt servo method is used.

A conventional pickup position adjustment device is shown, for example, in "Laser Disc Technical Book" (Published by Ni ASCII Co., Ltd., November 1, 1986), pages 96 to 98.

A conventional pickup position adjusting device will be described below.

FIG. 9 shows this conventional pickup position adjusting device. In FIG. 9, reference numeral 1 denotes a disk as an information medium, which is mounted on a turntable 2 and clamped by a clamper 3. 4 is a turntable 2. This is a spindle that rotates the disk 1 together with the clamper 3. Reference numeral 5 denotes an optical pickup for reading information recorded on the disc 1, and is slidably engaged with the guide shaft 6. 7 is a guide fulcrum that supports the end of the guide shaft 6 near the spindle 4;
It can be rotated around. Reference numeral 8 denotes a movable support member that supports the other end of the guide shaft 6, and a tilt adjustment screw 9 having a thread formed on the outer periphery is screwed into the movable support member 8. 10 is a tilt adjustment motor that rotates the tilt adjustment screw 9. Light emitting element 11. Light receiving elements 12 and 13 are provided on the optical pickup 5 and constitute tilt detection means. Light receiving element 12
13 enters the tilt adjustment drive circuit 15 and drives the tilt adjustment motor 10.

The operation of the pickup position adjusting device configured as described above will be explained below.

First, the disk 1 is rotated by the spindle 4, and the optical pickup 5 is conveyed along the guide shaft 6 from the inside to the outside of the disk 1 by a conveying means (not shown), and reads information on the disk 1. At this time, the light emitted from the light emitting element 11 on the optical pickup 5 and reflected by the disk 1 is detected by the light receiving element 12.13, and this detection (No. 3 enters the motor drive circuit 15.
If the light receiving elements 12 and 13 are tilted, the intensity of the reflected light received by the light receiving elements 12 and 13 will differ, so the tilt adjustment motor 10 is driven so that these are balanced, and the movable support member 8 is moved up and down by rotation of the tilt adjustment screw 9. Then, the guide shaft 6 is tilted about the guide fulcrum 7, and the laser beam from the optical pickup 6 is adjusted to be irradiated perpendicularly to the disk 1. The state at this time is shown by a two-dot chain line. At this time, the distance 16 between the optical pickup 5 and the disk 1 changes, but the optical pickup 5 has a built-in objective lens that focuses the laser beam on the disk 1.
It is designed to follow changes in the distance between the optical pickup 5 and the disk 1 within a certain range.

However, in this method, only the tilt of the optical pickup is adjusted, so if the disk is deflected or warped, the distance between the optical pickup and the disk will change significantly, and the objective lens of the optical pickup will The problem is that the laser beam cannot be focused on the disk, the beam spot diameter becomes large, the S/N of the reproduced signal deteriorates, and the reproduced image becomes distorted.

The present invention solves the above-mentioned conventional problems, and provides a pickup position adjustment device that can keep both the inclination and distance of the optical pickup relative to the disk constant, no matter how bent or warped the disk is. The purpose is to provide.

Means for Solving the Problems To achieve this object, the pickup position adjustment device of the present invention includes an optical pickup, a base on which the optical pickup is mounted, a tilt adjustment means for adjusting the tilt of the optical pickup, and an optical pickup position adjusting device. An inclination adjustment drive means for driving the inclination adjustment means according to the inclination between the pickup and the disk, a height adjustment means for adjusting the distance between the optical pickup and the disk, and a height adjustment means according to the distance between the optical pickup and the disk. and a height adjustment drive means for driving the height adjustment drive means.

Effect of the Invention With the above-described configuration, the present invention drives the inclination adjustment means and the height adjustment means with respective drive means, thereby keeping the distance between the optical pickup and the disk constant and ensuring that the laser beam is always irradiated perpendicularly to the disk. Adjust to.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 shows a pick according to a first embodiment of the present invention In FIG. 1, 22 is a rotating arm, the end of which is closer to the spindle 4 is rotatably supported on an arm rotation fulcrum 23, The other end is supported by an arm support member 24. Reference numeral 25 denotes a height adjustment screw attached to the height adjustment motor 26, and a screw formed on the outer periphery is screwed into the arm support member 24. The height adjustment drive circuit 27 drives the arm drive motor 26 based on a signal from the pickup. Rotating arm 22. Arm support member 24. Height adjustment screw 25. The height adjustment motor 26° and the height adjustment drive circuit 27 constitute a height adjustment drive means. The other parts are the same as those explained in FIG. 9.

In FIG. 2, the base 20 is slidably engaged with the guide shaft 6. The height adjustment means includes a height adjustment member 21, which is rotatably attached to the base 20 by a pin 21a. The optical pickup 5 has bins 5a and 5b.
is planted, and the bottle 5a engages with the groove formed in the base 20 and the groove formed in the height adjustment member 21, and the bottle 5a
b engages with a groove formed in the base 20 so that the optical pickup 5 moves perpendicularly to the plane formed by the two guide shafts 6. Further, a bin 21b is installed on the height adjustment member 21 and is engaged with the rotating arm 22. On the optical pickup S, a light emitting element 11 and a light receiving element 12, 13 constituting a tilt detection means are mounted.
These are equivalent to those explained in FIG.

The operation of the pickup position adjusting device of this embodiment configured as described above will be described below.

In FIG. 1, the operation of adjusting the laser beam of the optical pickup S so that it irradiates the disk 1 perpendicularly is the same as that described with reference to FIG. Here, when the distance between the disk 1 and the optical pickup 5 increases, an error signal of the distance between the optical pickup 5 and the disk 1 obtained from the optical pickup 5 enters the height adjustment drive circuit 27 and drives the height adjustment motor 26. do. When the height adjustment motor 26 rotates, the arm support member 24 is lowered by the height adjustment screw 25, and the rotation arm 22 is moved to the arm rotation fulcrum 2.
Rotate clockwise around 3. When the rotating arm 22 rotates, the height adjusting member 21 moves the bin 21b set up on it.
The optical pickup 5 is rotated clockwise around the bin 21a, and the optical pickup 5 is moved toward the disk 1 on the base 20, and the distance between the disk 1 and the optical pickup 5 is reduced. When this distance reaches a certain size, the height adjustment motor stops driving. The state at this time is shown by the 1st N: dotted chain line.

As described above, according to this embodiment, the height adjustment motor is driven by the interval error signal obtained from the optical pickup, rotates the rotation arm, rotates the height adjustment member on the base, By moving the optical pickup up and down with respect to the base, it is possible to keep the distance between the disk and the optical pickup constant.

FIG. 3 is a front view of a big-ass position adjustment device showing a second embodiment of the present invention. Figure 4 is its plan view,
FIG. 5 is a detailed perspective view of the pickup section.

In FIGS. 3, 4, and 5, reference numeral 30 is a rotating shaft that is provided parallel to the guide shaft 6 and has a spline shape on the outer periphery, and the end near the spindle 4 is rotated and rotated by the rotating shaft fulcrum 36. It is rotatably supported. A rotating shaft gear 34 is attached to the other end of the rotating shaft 30, and meshes with a motor gear 35 attached to the height adjustment motor 26. The height adjustment motor 26 is mounted on the movable support member 8. The transmission gear 31 is connected to the base 20
The rotary shaft 30 passes through the rotary shaft 30 and is engaged with the spline. The height adjustment drive screw 32 is the transmission gear 3
It has a gear part that meshes with 1 and a threaded part that screws into the height adjustment nut 33. The height adjustment nut 33 engages the height adjustment member 21. The other parts are the same as those shown in FIGS. 1 and 2.

The operation of the pickup position adjusting device configured as described above will be described below.

In FIG. 3, the operation of adjusting the laser beam of the optical pickup 5 so that it irradiates the disk 1 perpendicularly is the same as that described with reference to FIG. 9. When the distance between the disk 1 and the optical pickup 5 increases, the distance between the optical pickup 5 and the disk 1 obtained from the optical pickup increases.
An error signal in the interval between the height and height is input to a height adjustment drive circuit (not shown) to drive the height adjustment motor 26. The rotational force of the height adjustment motor 26 is applied to the motor gear 342 rotating shaft gear 35° rotating shaft 30. Transmission gear 31. It is transmitted to the height adjustment drive screw 32 and lowers the height adjustment nut 33. Height adjustment nut 3
3, the height adjustment member 21 rotates clockwise around its fulcrum 21a, and the optical pickup 5 moves toward the disk 1 on the base 20, so that the distance between the disk 1 and the optical pickup S becomes smaller. . When this distance reaches a certain size, the height adjustment motor 26 stops driving. The state at this time is shown by a two-dot chain line.

As described above, according to this embodiment, the height adjustment motor is driven by the interval error signal obtained from the optical pickup, the rotation shaft is rotated, the height adjustment member on the base is rotated, and the optical pickup By moving the disc up and down with respect to the base, it is possible to keep the distance between the disc and the optical pickup constant.

FIG. 6 shows the third embodiment of the present invention. FIG.

In FIGS. 6 and 7, a base 20 is slidably attached to a fixed guide shaft 49 whose both ends are fixed. The end of the rotating arm 22 near the spindle 4 is rotatably supported by the arm ileal fulcrum 23, and the other end is engaged with the tilt adjustment screw 9. Reference numeral 10 denotes a tilt adjustment motor mounted on the movable support member 8, and a tilt adjustment screw 9 is attached to its rotating shaft, constituting tilt adjustment driving means. A height adjustment screw 25 attached to a height adjustment motor 28 is engaged with the movable support member 8, and constitutes a height adjustment drive means. In FIG. 7, reference numeral 40 denotes an inclination adjustment member rotatably attached to the base 20 by a pin 40a, and a pin 40b is planted therein, which engages with a groove formed in the rotation arm 22. ing. Pins 5a and 5c are installed in the optical pickup 5, and the pin 5a is engaged with a groove formed in the base 20 and a groove formed in the height adjustment member 21. The other parts are the same as those shown in FIGS. 1 and 2.

The operation of the pickup position adjusting device configured as described above will be described below.

In FIG. 7, the disk 1 is rotated by the spindle 4, and the base 20 on which the optical pickup 5 is mounted is driven along the guide shaft 6 from the inside to the outside of the disk 1 by a driving means (not shown), and the disk 1 is rotated by the spindle 4. 1
Read the information above.

At this time, light emitted from the light emitting element 11 on the optical pickup S and reflected on the disk is detected by the light receiving element 12.13, and this detection signal is input to a tilt adjustment drive circuit (not shown). If the disk 1 is tilted, the intensity of the reflected light received by the light receiving elements 12 and 13 will differ, so the tilt adjustment drive motor 10 is driven so that these are balanced, and by rotating the tilt adjustment screw 9, the intensity of the reflected light received by the light receiving elements 12 and 13 changes. As shown in the figure, the rotating arm 22 is rotated in the circumferential direction of the disk around the arm rotation fulcrum 42. Bin 40b engaged in groove of rotating arm 22
The tilt adjustment member 40 rotates around 40a.

The tilt adjustment member 40 pushes the bin 5b to tilt the optical pickup 5 about the bin 5a. In this way, the laser beam from the optical pickup 5 is adjusted so as to be irradiated perpendicularly to the disk 1. In addition, in FIG. 6, when the distance between the disk 1 and the optical pickup 5 becomes smaller, the error signal of the distance between the optical pickup and the disk obtained from the optical pickup 5 enters the height adjustment drive circuit (not shown), and the height is adjusted. The adjustment motor 26 is driven. When the height adjustment motor 26 rotates, the movable support member 8 is raised by the height adjustment screw 25, and the rotating arm 2 is moved up as shown by the two-dot chain line.
2 is rotated counterclockwise around the arm rotation fulcrum 23. The height adjusting member 21 on which the rotating arm 22 rotates is rotated counterclockwise by the bin 21b around the bin 21a, and the optical pickup 5 is moved away from the disc 1 on the base 20 and the disc 1 and the optical The distance from the pickup 5 increases. The height adjustment operation is the same as that described with reference to FIGS. 1 and 2.

As described above, according to this embodiment, by driving the tilt adjustment motor and the height adjustment motor and rotating the rotation arm, the tilt adjustment member and the height adjustment member on the base are moved, and the optical pickup It is possible to make adjustments so that the distance between the laser beam and the disk is constant and the laser beam is irradiated perpendicularly to the disk.

Effects of the Invention As described above, the present invention provides a tilt adjustment means for adjusting the tilt of the optical pickup and a height adjustment means for adjusting the height, so that even if a disk with large warp or distortion is played back, the laser beam can be prevented. The light is irradiated perpendicularly to the disk in a focused state, increasing the S/N ratio of the reproduced signal and reducing crosstalk with adjacent tracks.

Furthermore, since there is no need to increase the dynamic range of the objective lens for focusing the optical pickup, the optical pickup can be made smaller and cheaper. In addition, since the tilt adjustment drive means and the height adjustment drive means are located outside the base to be transported, the wiring to the moving parts is the same as before, and the moving parts can be made smaller and lighter, so there is no load on the transport means. It can also be small.

[Brief explanation of drawings]

FIG. 1 is a front view of a pickup position adjusting device showing a pick embodiment in the first embodiment of the present invention, a front view of the pickup position adjusting device, FIG. 7 is a bottom view of the same, and FIG. 8 is a pickup part of the same. FIG. 9 is a front view showing a conventional pickup position adjusting device. 1... Disc, 2... Turntable, 3...
... Clamper, 4 river spindle, 5... Optical hickup 1 5a + 5bt 6c... Bin, 6... Guide shaft, 7... Guide fulcrum, 8... Movable support member, 9... Tilt adjustment screw, 10...Tilt adjustment motor, 11...
Light emitting element, 12.13... Light receiving element, 15.
...Tilt adjustment drive circuit, 2o...base, 2nd work...
・Height adjustment member, 21a, 21b...bin, 22
...Rotating arm, 23...Arm rotation fulcrum, 2
4... Arm support member, 25... Height adjustment screw, 2e... Height adjustment motor, 27... Height adjustment drive circuit, 30... Rotating shaft, 31... Transmission gear, 32... Height adjustment drive screw, 33... Height adjustment nut, 34... Rotating shaft gear, 35.
... Motor gear, 36... Rotating shaft fulcrum, 40...
・Tilt adjustment member, 40a, 40b...bin, 49
...Fixed guide shirt.

Claims (1)

[Claims] (1) An optical pickup that records and reproduces information signals by irradiating an information medium with a light beam and receiving reflected light or transmitted light from the information medium, a base on which the optical pickup is mounted, and the base. a conveyance means for conveying the information medium substantially parallel to the information medium; a tilt adjustment means for adjusting the inclination of the optical pickup by rotating the conveyance means about a fulcrum; a tilt adjusting drive means for driving the tilt adjusting means according to the tilt with respect to the information medium; a height adjusting means for adjusting the distance between the optical pickup and the information medium; A pickup position adjustment device comprising: height adjustment drive means for driving the height adjustment means according to the distance between the pickup and the information medium. (2) a driving member having one end connected to the tilt adjusting means and the height adjusting means and the other end connected to the tilt adjusting driving means and the height adjusting driving means; 2. The pickup position adjusting device according to claim 1, wherein the tilt adjusting means and the height adjusting means are each driven independently depending on the driving direction.