JPS6371934A - Optical pickup driving device - Google Patents

Abstract

PURPOSE:To easily adjust a feeding shaft to a state in which objective feeding straight line is on an imaginary line in radial direction of an optical recording medium by supporting the feeding shaft at inner peripheral position of a discoid recording medium and making another end correctable to outer peripheral side position. CONSTITUTION:By movement of an optical pickup 14 guided by a feeding shaft 13, an objective feeding straight line 5 is made parallel to the feeding shaft 13 keeping a specified distance. By moving a feeding shaft adjusting section 20 provided on outer peripheral side around a feeding shaft support 10A provided in inner peripheral side of a discoid optical recording medium 1, the distance between the feeding shaft 13 and radius of the discoid optical recording medium 1 parallel to the shaft changes with movement of the feeding shaft 13. Accordingly, when the center 0 of the optical recording medium 1 is not on the extension of the objective feeding straight line 5 (i.e. not on the radius), adjusting can be made easily by moving the feeding shaft 13 according to the quantity of deviation.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Use The present invention relates to an optical pickup drive device, and is suitable for application to, for example, an optical pickup drive device used in a video disc player.

B. Summary of the Invention The present invention provides an optical pickup driving device in which one end of the feed shaft is supported at the inner circumferential position of a disc-shaped recording medium, and the other end is adjusted to an outer circumferential position.
The feed axis can be easily adjusted so that the objective lens feed line is on the virtual line in the radial direction of the optical recording medium.

C. Prior Art A track on a video disc has a structure in which optical pits for recording optical information are continuously arranged in a spiral shape from the inner circumference to the outer circumference.

For this reason, in an optical pickup, for example, three laser beams are formed using a grating based on laser light emitted from a half-door laser device, and a central laser spot for reproducing optical information and two laser beams on both sides thereof are formed on the disc. Two tracking laser spots are irradiated to accurately trace the track and read information recorded on the disc.

That is, as shown in FIG. 5, three laser spots IA and IB are located on the innermost track 6A on the disk l.
and IC are irradiated. The laser spot IA is a laser spot for optical information reproduction and focus servo. Laser spora 1-IB and IC are tracking servo laser spots that are irradiated with a predetermined offset in the direction perpendicular to the radius (i.e., tangential direction), and half of the preceding laser spot IB is The laser spot IC is configured to protrude inside the track 6A by a predetermined amount, and half of the laser spot IC that follows is configured to protrude outside the track 6A by a predetermined amount.

The optical pickup (not shown) slightly moves the positions irradiated by the laser spots (LA, IB, and IC) in the radial direction of the disk 1 in response to changes in the amount of reflected light obtained from the laser spots IB and IC, thus slightly changing the position of the laser spot (LA, IB, and IC) in the radial direction of the disk 1. It is designed to be able to accurately track and follow the undulations.

Furthermore, the DC component included in the tracking servo signal obtained from the laser spots IB and IC is used as a control signal for a so-called slider motor that moves the optical pickup in the radial direction of the disk 1. As a result, the optical pickup moves the laser spot lA for optical recording and reproduction on the disk 1 toward the inner circumferential side of the disk l on the objective lens feed straight line 5A extending in the radial direction while being guided by the feed shaft (not shown). Track 6B on the outer circumference side in order from track 6A on
...Move to 6C, 6D.

D Problems to be Solved by the Invention However, in the optical pickup drive device configured as described above, as shown in FIG. Assuming that the optical pickup is at a position 5B shifted by a distance ΔX, the three laser spots 3A when the optical pickup is tracking the track 6B on the inner circumference side of the disk 1
There is a possibility that 3B and 3C will simultaneously irradiate almost the top of track 6B.
Since a predetermined offset for B cannot be obtained, a normal tracking signal cannot be detected.

Similarly, when the optical pickup is tracing the track 6C on the outer circumferential side of the disk 1, there is a possibility that the three laser spots 4A, 4B and 4C will not be able to detect the tracking signal.

The offset deviation angle Δθ at this time can be expressed as follows. Here, ΔX is the distance between the curve line R in the radial direction of the disk 1 and the objective lens feed straight line 5, and r is the distance between the center of the objective lens 14A and the center 0 of the disk 1 (i.e., the length of the radius R). It is).

As shown in this equation (1), the offset deviation angle Δ
θ is larger at a position where the radius R is smaller, and becomes smaller as the radius R becomes larger.

This phenomenon is caused by the so-called radius dependence (RD).
ial dependence)).

In order to avoid problems caused by this radius dependence, in conventional optical pickup drive devices, the mechanical precision in positioning the objective lens feed straight line 5A with respect to the virtual line R in the radial direction of the disk is made as high as possible. In order to achieve this, for example, the spindle motor attachment part and the feed shaft have been integrated, molded using an aluminum die-casting method, and further precision-machined.

However, in this case, there was a problem that in addition to not being able to simplify the manufacturing process, it was also impossible to reduce the weight of the video disc player as a whole.

For this reason, the mounting part of the spindle motor and the feed shaft are separately provided, and the optical pickup drive device with the feed shaft is manufactured using so-called outsert molding, in which a resin material is poured into a mold that sandwiches the chassis. In addition to fixing the mounting parts on the chassis using the above method, the laser optical system of the optical pickup is adjusted while the disk is rotating.
A method has been proposed in which the irradiation position of the laser spot is shifted in the tangential direction of the disk, thereby performing the RD sub-adjustment.

However, with this method, it is necessary to adjust the optical pickup while the disk is rotating, which complicates the adjustment work, and there is also the problem that accurate RD sub-adjustment cannot be performed, and the method is still unsatisfactory.

The present invention has been made in consideration of the above-mentioned problems, and by providing a feed axis adjustment section that allows the position of the feed axis to be easily adjusted in an optical pickup drive device, it is possible to more easily and accurately adjust the RDffl. The purpose of this paper is to propose an optical pickup driving device that is capable of adjusting the speed of the optical pickup.

E Means for Solving the Problem In order to solve this problem, in the present invention, a laser spot is used to drive the optical pickup 14 which is designed to read the optically recorded information on the disc-shaped optical recording medium 1. In the optical pickup driving device, the optical pickup 1
A feed shaft support portion that supports the feed shaft 13 so as to be rotatable around one end on the inner peripheral side of the feed shaft 13 that is guided when moving the feed shaft 13 in the radial direction of the optical recording medium! OA and a feed axis adjustment section 20 provided on the outer peripheral side of the optical recording medium 1 so as to be movable in the tangential direction of the optical recording medium 1 and fixed.

By moving the F-action optical pickup 14 while being guided by the feed shaft 13, the objective lens feed straight line 5 is kept parallel to the feed shaft 13 and at a predetermined distance.

Furthermore, by moving the feed axis adjustment section 20 provided on the outer circumference side around the feed axis support section 10A provided on the inner circumference side of the disc-shaped optical recording medium 1, the feed axis 13 and The distance between the radius of the disk-shaped optical recording medium l parallel to the
It changes according to the movement of the feed shaft 13.

(Then, the objective lens feeding straight line 5 of the optical pickup 14
When the center 0 of the optical recording medium 1 is not on the extension line (that is, not on the radius), the feed axis 13
It can be easily adjusted by moving.

Embodiment G An embodiment of the optical pickup driving device according to the present invention will be described in detail below with reference to a concave surface.

1 and 2, which shows the main parts of FIG. 1 obliquely from arrow e.
In the figure, a spindle motor 12 on which a disk 1 is placed is attached to the center of a chassis 10. Further, a rectangular opening 10C having a longitudinal direction in the radial direction of the disk 1 is provided on the chassis 10.

On the short side of the opening 10C on the spindle motor 12 side,
For example, a first feed shaft support portion 10A made of resin material by outsert molding is provided. Also opening 10C
A feed shaft adjustment portion 20 having a second feed shaft support portion 15A formed by outsert formation of a resin material is provided on the opposite outer short side portion of the feed shaft adjusting portion 20 .

The first feed shaft support portion 10A is located at a position where the virtual line connecting the first feed shaft support portion 10A and the center O of the disk 1 and the feed shaft 13 (or an extension of the feed shaft 13) are not perpendicular to each other. are selected and installed. This includes the objective lens feed straight line 5 and the feed axis 1, which can be adjusted by moving the feed axis 13.
When the distance between the feed axis 13 and the objective lens feed straight line 5 is limited to less than the length of the imaginary line L1, and the position where the feed axis 13 and the imaginary line L1 are orthogonal is selected, the distance between the feed axis 13 and the objective lens feed straight line 5 is
This is because if the distance is greater than the distance between the feed shaft 13 and the imaginary line R of the radius parallel to the feed shaft 13, adjustment cannot be made by moving the feed shaft 13.

Furthermore, the first feed shaft support section 10A and the feed shaft adjustment section 20
The positional relationship of the feed shaft 1 is when the feed shaft 13 is horizontally mounted.
3 becomes almost parallel to the radial direction of the disk 1, and the optical pickup 14 is guided by the feed shaft 13 via the bearing 14B and moves in the direction indicated by the arrow f or g (i.e., the movement trajectory of the objective Lens feed straight line 5)
is set so that it almost coincides with the radial direction of the disk 1 (that is, the center O of the spindle motor 12 is on the extension of the objective lens feeding straight line 5).

Here, the first feed shaft support section 10A and the feed shaft adjustment section 20
Both of the second feed shaft support parts 15A have a U-shaped cross section, and a space slightly larger than the diameter of the feed shaft 13 is provided inside. Further, the width of the openings arranged to face each other to receive the feed shaft 13 is selected to be approximately equal to the diameter of the feed shaft 13, and
3 is tapered to have a U-shaped cross section. Accordingly, the feed shaft 13 moves the feed φ force support portions 10B and 15F.
It is designed to be able to move smoothly in the direction shown by arrow C or d around the feed shaft support portion 10B while being supported by the feed shaft support portion 10B.

Here, the feed shaft adjustment section 20 has a feed shaft moving member 15 that can move in the lateral direction indicated by arrows a or b.

The feed shaft moving member 15 has a main body in the shape of a rectangular thick plate, and has a second feed shaft support portion 15A approximately in the center of its upper surface.
A meshing portion 15D having a predetermined pitch is formed on the opposite side of the feed shaft 13, and a U-shaped notch 15E that engages with the movement adjustment lever 16 is provided at one end. It is being

Further, the main body of the moving section is attached to the chassis 10 by two fixing parts 15B at the tips of a thin plate-like temporary spring part 15C that extends at a predetermined interval in the opposite direction to the feed shaft 13.

A lever part 16B of the movement adjustment lever 16 is engaged with the U-shaped notch 15E. The movement adjustment lever 16 is configured to move the notch 1 with the lever portion 16B by rotating a screw attached to the center portion 16A in the direction indicated by arrow j or k.
5E is pressed, and as a result, the feed shaft moving member 15 is moved in the direction shown by arrow a or b.

Further, the positioning member 17 has a second meshing portion 17B at a position opposite to the first meshing portion 15D of the feed shaft moving member 15.
is mounted on the chassis 10 by a fixed portion 17A via a flexible neck portion 17C.

A meshing lever 18 is provided behind the meshing portion 17B, and by rotating its pressing portion 18A by 906 turns in the direction indicated by arrow m around the threaded portion 18B, the positioning member 17 is moved by the pressing portion 18A. Press the meshing portion 17B in the direction indicated by the arrow n to mesh with the first meshing portion 15D,
This allows the feed shaft moving member 15 to be fixed.

Thus, the movement of the feed shaft moving member 15 is adjusted as follows. That is, when the threaded portion 16A of the movement adjustment lever 16 is rotated in the direction of arrow j or k using, for example, a screwdriver, the main body of the moving portion of the feed shaft moving member 15 is rotated by the temporary spring portion 15.
The feed shaft 13 is moved in the direction of the arrow C or d while being pivotally supported by the first and second feed shaft supports 10A and 15A. Ru.

After adjusting the movement adjustment lever 16 in this way and determining the position of the feed shaft 13 in the direction of arrow C or d, the meshing part lever 18
The threaded portion 18B is rotated using, for example, a screwdriver, and the pressing portion 18A is pressed against the meshing portion 17B of the positioning member 17 and brought into mesh with the first meshing portion 15D of the feed shaft moving member 15. In this way, the feed shaft moving member 15 is fixed, and as a result, the so-called RD sub-adjustment, in which the feed shaft 13 is adjusted parallel to the radial direction of the disk, can be performed.

In the above configuration, as shown in FIG.
When the movement locus of the objective lens 14A of the optical pickup 14, that is, the objective lens feed straight line 5B, is shifted to the left by a distance ΔX with respect to the radial virtual line R,
The feed axis adjustment unit 20 is moved in the direction of arrow a, thereby moving the feed axis 13 in the direction of arrow C, and the level of the tracking signal obtained from the tracking laser beam from the optical pickup 14 reaches a predetermined value. The feed shaft 13A is fixed at a position such that In this way, the virtual line R in the radial direction of the disk l can be adjusted to match the objective lens feeding straight line 5B of the objective lens 14A of the optical pickup 14.

Conversely, as shown in FIG. 4, when the objective lens/feed line 5B of the optical pickup 14 is shifted to the right by a distance ΔX with respect to the virtual WR in the radial direction of the disk 1, The feed axis adjustment section 20 can be moved in the direction of the arrow A, and the feed axis 13B can be fixed at a position where the virtual line R and the objective lens feed straight line 5B match in the same manner as described above.

According to the above configuration, the feed shaft is moved by the feed shaft adjusting section on the outer circumferential side with one end on the inner circumferential side of the disk as the rotation center to obtain the RD sub-adjustment. It is no longer necessary to make the accuracy so high, and furthermore, it is possible to realize an optical pickup driving device that can perform RD3Pip more easily and with higher accuracy than the one that performs RD3Pip by adjusting the optical pickup.

In the above-mentioned embodiment, a feed axis adjustment section having a structure as shown in Figs. 1 and 2 was used, but the structure of the feed axis adjustment section is not limited to this. Any configuration is acceptable as long as it can be moved and fixed in the tangential direction to the track.

Furthermore, in the above embodiment, the position of the feed shaft support part is
If we assume that the distance between the extension line of the feed shaft and the center of the disk perpendicularly to L8 is L8, and the distance between the center of rotation of the feed shaft and the center of the disk 0 is L, then t, <1. , but instead of this, it may be set so that Lz > l, , (in short, if Lt = L, then it can be placed anywhere near the spindle motor. A similar effect can be obtained.

Further, in the above-described embodiment, an embodiment in which the present invention is applied to an optical pickup drive device of an optical disk reproducing device has been described, but the present invention is not limited to this, and can be applied to reproducing other disc-shaped optical recording media. The present invention can be widely applied to optical pickup drive devices for optical pickups.

Effects of the Invention As described above, according to the present invention, in the optical pickup driving device, the feed axis can be easily moved and adjusted, so that the straight line of the objective lens feed of the optical pickup can be corrected with high accuracy. Therefore, it is possible to realize an optical pickup drive device with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the main parts of a video disc player using an optical pickup drive device according to the present invention, FIG. 2 is an enlarged perspective view of the feed axis adjustment section of FIG. 1 viewed from arrow e, and FIG. and FIG. 4 is a linear plan view showing the relationship between the feed axis, the objective lens feed line, and the radial adjustment of the disk;
FIG. 5 is a route map showing the relationship between the laser spot, the objective lens feed straight line, and the tracks on the disk. ■...Ki disk, 5...Objective lens feed straight line, 10A,...Feed shaft support part, 13.
...Feed axis, 14...Optical pickup,
20...Feed axis adjustment section.

Claims (1)

[Claims] An optical pickup driving device for driving an optical pickup configured to read optically recorded information on a disk-shaped optical recording medium using a laser spot, the optical pickup being driven in a radial direction of the optical recording medium. a feed shaft support part that supports the feed shaft so as to be able to rotate around one end on the inner circumference side of the feed shaft guided when the optical recording medium is moved; and a feed axis adjustment section provided to be movable and fixed, and by moving and fixing the feed axis adjustment section, the feed axis is positioned, whereby the objective lens feed straight line of the optical pickup is adjusted. An optical pickup driving device characterized in that it can be adjusted to match a virtual line in the radial direction of the optical recording medium.