JPH0677319B2 - Optical pickup drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A Field of Industrial Application The present invention relates to an optical pickup driving device, and is preferably applied to an optical pickup driving device used in, for example, a video disc player.

B. Summary of the Invention According to the present invention, in the optical pickup drive device, one end of the feed shaft is supported at the inner peripheral side position of the disk-shaped recording medium, and the other end can be corrected to the outer peripheral side position. The feed axis can be easily adjusted so that the objective lens feed line is on a virtual line in the radial direction of the optical recording medium.

C Prior Art A video disk track 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 the optical pickup, for example, based on the laser light emitted from the semiconductor laser device, three laser beams are formed by grating, and a central laser spot for reproducing optical information and two laser beams on both sides thereof are formed on the disk. The laser spots for tracking are emitted, and the recorded information on the disk is read while accurately tracing the track.

That is, as shown in FIG. 5, three laser spots 1A, 1B and 1C are provided on the innermost track 6A on the disk 1.
Is being irradiated. The laser spot 1A is a laser spot for reproduction of optical information and focus servo. Further, the laser spots 1B and 1C are laser spots for tracking servo that are irradiated so as to have a predetermined offset in a direction orthogonal to the radius (that is, a tangential direction), and the preceding laser spot 1B is half of the laser spot. Truck
A predetermined amount of the laser spot 1C is projected to the inside of 6A, and half of the laser spot 1C that follows is projected to the outside of the track 6A by a predetermined amount.

Optical pickups (not shown) are laser spots 1B and 1C.
Depending on the change in the amount of reflected light obtained, the laser spot
The irradiation positions of 1A, 1B, and 1C are finely moved in the radial direction of the disk 1, and thus, the slight undulations of the track 6 can be followed to accurately perform tracking.

Further, the DC component contained in the tracking drive signals obtained from the laser spots 1B and 1C is used as a so-called slider motor control signal for sending the optical pickup in the radial direction of the disk 1. As a result, the optical pick-up is guided by the feed shaft (not shown) and the laser spot 1A for optical recording / reproduction on the disk 1 is extended in the radial direction on the objective lens feed line 5A on the inner circumference side of the disk 1. Tracks 6A to 6C, 6D on the outer peripheral side in order from the track 6A.

D. Problem to be solved by the invention D In the optical pick-up driving device configured as described above, as shown in FIG. 5, the objective lens feed line 5A is parallel to the virtual line R in the radial direction of the disk 1. Assuming that the optical pickup is at the position 5B which is displaced by the distance Δx, the three laser spots 3A, 3B and 3C when the optical pickup is tracking the inner track 6B of the disk 1 will be described.
May illuminate almost the entire track 6B at the same time. In this state, a predetermined offset cannot be obtained for the track 6B, and a normal tracking signal cannot be detected.

Similarly, when the optical pickup traces the track 6C on the outer peripheral side of the disk 1, the three laser spots 4A, 4B and 4C may not be able to detect the tracking signal in the same manner.

If the offset angle Δθ at this time is expressed by an equation, Becomes Here, Δx is the distance between the virtual line R in the radial direction of the disk 1 and the objective lens feed line 5, and r is the distance between the center of the objective lens 14A and the center O of the disk 1 (that is, the length of the radius R). ). As shown in the equation (1), the offset angle Δθ of the offset increases as the radius R decreases, and decreases as the judgment R increases. Such a phenomenon is called the radius dependence (RD
(Radial dependence)).

In order to avoid the inconvenience due to this radius dependence, in the conventional optical pickup drive device, the mechanical accuracy in positioning the objective lens feed line 5A with respect to the virtual line R in the radial direction of the disk is set as high as possible. In order to obtain it, for example, the spindle motor mounting portion and the feed shaft were integrated, and the aluminum die cast method was used for molding, and further precise machining was performed.

However, in this case, in addition to the fact that the manufacturing process cannot be simplified, there is a problem that the weight of the video disc player as a whole cannot be reduced.

For this reason, the spindle motor mounting part and the feed shaft are separately provided, and the optical pickup drive device provided with the feed shaft is a so-called outsert molding in which a resin material or the like is poured into a mold sandwiching the chassis. While fixing the mounting parts on the chassis by the method of, adjust the laser optical system of the optical pickup while rotating the disk,
A method has been proposed in which the irradiation position of the laser spot is shifted in the tangential direction of the disk so that the RD adjustment is performed.

However, in such a case, it is necessary to adjust the optical pickup while the disk is rotating, which complicates the adjustment work and causes a problem that accurate RD adjustment cannot be performed, which is still insufficient.

The present invention has been made in view of the above problems, and in the optical pickup drive device, by providing a feed shaft adjusting portion capable of easily adjusting the position of the feed shaft, it is much easier and more accurate. It is intended to propose an optical pickup drive device capable of RD adjustment.

E Means for Solving the Problems In order to solve the above problems, in the present invention, the optical pickup 14 which is adapted to read the optical recording information of the disc-shaped optical recording medium 1 by using the laser spot is driven. In the optical pick-up drive device for feeding, a feed shaft support portion for rotatably supporting one end on the inner peripheral side of the feed shaft 13 guided when moving the optical pick-up 14 in the radial direction of the optical recording medium. 10A and a feed axis adjusting unit 20 provided on the outer peripheral side of the optical recording medium 1 so as to be movable and fixed in the tangential direction of the optical recording medium 1.

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

Further, by moving the feed shaft adjusting portion 20 provided on the outer peripheral side around the feed shaft supporting portion 10A provided on the inner peripheral side of the disc-shaped optical recording medium 1, the feed shaft 13 and The distance from the radius of the parallel disk-shaped optical recording medium 1 is
It changes according to the movement of 13.

Thus, when the center O of the optical recording medium 1 is not on the extension line of the objective lens feed line 5 of the optical pickup 14 (that is, not on the radius), the feed shaft 13 can be easily adjusted according to the deviation amount. You can

G Embodiment An embodiment of the optical pickup drive device according to the present invention will be described in detail below with reference to the drawings.

1 and FIG. 2 is a perspective view showing the main part of FIG.
In the figure, a spindle motor 12 on which the disk 1 is mounted is attached to the center of the chassis 10. A rectangular opening 10C having a longitudinal direction in the radial direction of the disk 1 is provided on the chassis 10.

A first feed shaft support portion 10A made of, for example, a resin material by outsert molding is provided on a short side portion of the opening 10C on the spindle motor 12 side. Further, the feed shaft adjusting portion 20 having a second feed shaft supporting portion 15A similarly formed by outsert formation of a resin material is provided on the opposite short side portions of the opening 10C.
Is provided.

Note that the first feed shaft support portion 10A is the first feed shaft support portion 10A.
And a virtual line L ₁ connecting the center O of the disk 1 and the feed shaft 13
(Or an extension line of the feed shaft 13) is selected and attached at a position that is not orthogonal to. This is because the distance between the objective lens feed line 5 and the axis 13 that can be adjusted by moving the feed shaft 13 is a virtual line.
The length is limited to the length of L ₁ or less, and when the feed shaft 13 and the imaginary line L ₁ are selected at a position orthogonal to each other, the distance between the feed shaft 13 and the objective lens feed straight line 5 becomes equal to the feed shaft 13 and the feed shaft 13. Is larger than the distance from the virtual line R having a radius parallel to the feed axis 13
This is because adjustments cannot be made due to the movement of.

Further, the positional relationship between the first feed shaft support portion 10A and the feed shaft adjustment portion 20 is such that when the feed shaft 13 is laid horizontally, the extension direction of the feed shaft 13 becomes substantially parallel to the radial direction of the disk 1, and
The movement locus (that is, the objective lens feed straight line 5) when 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 substantially coincides with the radial direction of the disk 1 (that is, Spindle motor 12
(The center O of the exists on the extension of the objective lens feed line 5)
Is set.

Here, both the first feed shaft support portion 10A and the second feed shaft support portion 15A of the feed shaft adjustment portion 20 have a U-shaped cross section, and inside thereof are slightly larger than the diameter of the feed shaft 13. There is a large space. The width of the openings arranged to receive the feed shaft 13 so as to face each other is selected to be approximately the same as the diameter of the feed shaft 13, and the portion in contact with the feed shaft 13 has a U-shaped cross section. When the feed shaft adjusting portion 20 is moved laterally with respect to the feed shaft 13 as indicated by an arrow a or b, the feed shaft adjusting portion 20 is accordingly tapered.
While being pivotally supported by the feed shaft support portions 10B and 15F, it can be smoothly moved around the feed shaft support portion 10B in the direction indicated by the arrow c or d.

Here, the feed shaft adjusting unit 20 has a feed shaft moving member 15 that can move in the lateral direction indicated by the arrow a or b.

The feed shaft moving member 15 has a rectangular thick plate-shaped moving portion main body, and a second feed shaft supporting portion 15A is arranged substantially in the center of the upper surface thereof, and a predetermined pitch is provided on the side opposite to the feed shaft 13. Is formed with a toothed portion 15D, and a U-shaped cutout portion 15E that engages with the movement adjusting lever 16 is provided at one end.

Further, the moving portion main body is provided with a thin plate-shaped leaf spring portion 15C extending in a direction opposite to the feed shaft 13 at a predetermined interval, so that the distal end thereof is
It is mounted on the chassis 10 by means of one fixed portion 15B.

The U-shaped cutout 15E has a lever portion 16B of the movement adjusting lever 16
Are engaged. The movement adjusting lever 16 pushes the cutout portion 15E by the lever portion 16B by rotating the screw attached to the central portion 16A in the direction shown by the arrow j or k, and as a result, the feed shaft moving member 15 is moved by the arrow a. Alternatively, it is moved in the direction indicated by b.

Further, the positioning member 17 having the second meshing portion 17B at a position facing the first meshing portion 15D of the feed shaft moving member 15 is provided on the chassis 10 by the fixing portion 17A via the flexible neck portion 17C. It is installed.

A toothing lever 18 is provided behind the meshing portion 17B, and the pushing portion 18A is positioned by the pushing portion 18A by rotating the pushing portion 18A about the screw portion 18B in the direction indicated by the arrow m. The meshing portion 17B of the member 17 is pressed in the direction indicated by the arrow n to mesh with the first meshing portion 15D, whereby the feed shaft moving member 15 can be fixed.

Thus, the movement of the feed shaft moving member 15 is adjusted as follows. That is, when the screw portion 16A of the movement adjusting lever 16 is rotated in the direction of arrow j or k by a driver or the like,
The moving part main body of the feed shaft moving member 15 moves in the direction of arrow i or h against the elastic force of the leaf spring part 15C, whereby the feed shaft moving member 15 moves.
13 is moved in the direction of arrow c or d while being pivotally supported by the first and second feed shaft support portions 10A and 15A.

Thus, after adjusting the movement adjusting lever 16 to determine the position of the feed shaft 13 to the arrow c or d, the screw portion 18B of the meshing lever 18 is rotated by, for example, a screwdriver, and the pushing portion 18A of the positioning member 17 is rotated. It is pressed against the meshing portion 17B and meshed with the first meshing portion 15D of the feed shaft moving member 15. Thus, the feed shaft moving member 15 is fixed, and as a result, so-called RD adjustment can be performed to adjust the feed shaft 13 in parallel with the radial direction of the disk.

In the above structure, as shown in FIG.
With respect to a virtual line R in the radial direction of the objective lens 14A of the optical pickup 14, that is, the objective lens feed line 5B.
Is displaced to the left by the distance Δx, the feed shaft adjusting unit 20 is moved in the direction of the arrow a, so that
13 is moved in the direction of arrow c so that the level of the tracking signal obtained from the laser beam for tracking from the optical pickup 14 becomes a predetermined value.
Fix A. Thus, the imaginary line R in the radial direction of the disk 1 and the objective lens feed line 5B of the objective lens 14A of the optical pickup 14 can be adjusted to coincide with each other.

On the contrary, as shown in FIG. 4, when the objective lens feed line 5B of the optical pickup 14 is displaced rightward from the virtual line R in the radial direction of the disk 1 by a distance Δx, The axis adjusting unit 20 can be moved in the direction of the arrow b, and the feed shaft 13B can be fixed at the position where the virtual line R and the objective lens feed line 5B coincide with each other in the same manner as described above.

According to the above configuration, the feed shaft can be moved by the feed shaft adjusting portion on the outer peripheral side with one end on the inner peripheral side of the disk as the center of rotation for RD adjustment. It is not necessary to increase the mechanical accuracy so much, and it is possible to realize an optical pick-up drive device that can perform RD adjustment easily and with high accuracy as compared with a device that adjusts the optical pick-up.

In the above-described embodiment, the feed shaft adjusting unit having the structure shown in FIGS. 1 and 2 is used, but the structure of the feed shaft adjusting unit is not limited to this. Any structure may be used as long as it can be moved and fixed in the tangential direction with respect to the track.

Further, in the above-mentioned embodiment, the position of the feed shaft support is
Let L _{2 be} the distance perpendicular to the center O of the disc on the extension line of the feed axis and L ₁ be the distance between the center of rotation of the feed axis and the center O of the disc, so that L ₂ <L _1. I set it,
Alternatively, it may be set such that L ₂ > L ₁ .
The same effect can be obtained by arranging it anywhere.

Further, in the above-mentioned embodiment, one embodiment in which the present invention is applied to the optical pickup driving device of the optical disc reproducing apparatus has been described, but the present invention is not limited to this, and other disc-shaped optical recording media are reproduced. The present invention can be widely applied to an optical pick-up drive device for an optical pick-up.

H Effect 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 objective lens feed line of the optical pickup can be corrected with high accuracy. It is possible to realize an optical pick-up drive device having a simple structure to be obtained.

[Brief description of drawings]

FIG. 1 is a plan view showing a main part of a video disk player using the optical pickup drive device according to the present invention, and FIG. 2 is an enlarged perspective view of the feed shaft adjusting part of FIG. 4 and FIG. 4 are schematic plan views showing the relationship between the feed axis, the objective lens feed line, and the radial adjustment of the disc, and FIG. 5 shows the relation between the laser spot, the objective lens feed line, and the track on the disc. It is a schematic diagram. 1 …… Disk, 5 …… Objective lens feed straight line, 10A ……
Feed shaft support, 13 …… Feed shaft, 14 …… Optical pickup,
20 …… Feed axis adjustment section.

Claims (1)

[Claims] 1. An optical pick-up driving device for driving an optical pick-up adapted to read optical recording information on a disc-shaped optical recording medium by using a laser spot, wherein the optical pick-up is arranged in a radial direction of the optical recording medium. A feed shaft support portion that supports the feed shaft so as to be rotatable around one end on the inner peripheral side of the feed shaft that is guided when moving, and a tangential direction of the optical recording medium to the outer peripheral side of the optical recording medium. And the feed axis adjusting portion provided so as to be fixed, and the feed axis is positioned by moving and fixing the feed axis adjusting portion, whereby the objective lens feed straight line of the optical pick-up is set to the above. An optical pickup drive device, which can be adjusted so as to match an imaginary line in a radial direction of an optical recording medium.