JP2000036118A - Mechanism for corecting optical axis of optical head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the structure, to lower the cost, to facilitate the assembly, and to reduce the number of parts. SOLUTION: The inclination of the shaft 5 that guides an optical head 2 in the radial direction of a disk 1 for the purpose of correcting the optical axis of the optical head 2 against the disk 1 is adjusted. The holding member 8a, which holds a position of the shaft 5 against the chassis 8 of the inner circumferential side of the disk the guide member 8b which movably guides the shaft 5 in the outer circumferential side of the disk only in the vertical direction to the surface of the disk 1 are provided in the chassis 8. A leaf spring 11 is used as an elastic member that presses the shaft 5 in this movable direction and in such a manner so as to be away from the chassis, while a screw 12 is used as a means for regulating a position for receiving this pressed shaft 5. The shaft 5 is received in a crossed proximity to the rising part of the leaf spring 11. The leaf spring 11 is provided with a projection 11a which is fitted to the recess of the chassis 8 and which determines a position against the chassis 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a CD, a CD-R
The present invention relates to a mechanism for correcting an optical axis of an optical head (also referred to as an optical pickup) for recording a signal on or reproducing a signal from a disk such as an OM, DVD, LD, or MD with respect to the disk.

[0002]

2. Description of the Related Art Generally, when the spot diameter is relatively large like a CD or when only normal reproduction is performed,
As long as the deviation of the optical axis from the movement guide portion of the optical head itself is not so large, the optical axis correcting mechanism of the optical head is not required. However, when the spot diameter is small and the recording density of the disc is high, such as in a DVD, the deviation of the optical axis becomes a serious problem. Even if an attempt is made to reduce the deviation of the optical axis of the optical head itself from the movement guide portion, there is a limit in manufacturing, and some measures other than the optical head itself are required.

Conventionally, in view of the above, in order to correct the optical axis of the optical head with respect to the disk so as to be vertical, there has been known an apparatus which adjusts a tilt of a shaft for guiding the optical head in a radial direction of the disk. ing. And in this device, a holding member attached to a chassis and holding a position of the shaft with respect to the chassis on the inner peripheral side of the disk, and attached to the chassis, the outer peripheral side of the shaft being perpendicular to the surface of the disk. A guide member that guides the shaft so as to be movable only in the direction, an elastic member that biases the shaft in the movable direction and away from the chassis, and receives the biased shaft, Position restricting means for restricting a position in the movable direction on the outer peripheral surface side of the disk.

FIGS. 7 to 10 show an example of the above-mentioned conventional optical axis correcting mechanism of an optical head. In these figures, 1 is a disk, 2 is an optical head, 3 is a turntable, 4 is a spindle motor, 5 is a shaft,
6 is a leaf spring, 7 is a tilt adjusting screw, 8 is a chassis, 9 is a screw, and 10 is a holder. The optical head 2 is provided with guide holes 2a, 2a and a guide portion 2b formed by notches. The shaft 5 penetrates through these guide holes 2a, and guides the optical head 2 in the radial direction of the disk 1.

The laser beam from the optical head 2 is designed to be emitted in a direction perpendicular to an imaginary axis passing through the guide hole 2a. Is generated. The spindle motor 4 is provided with a turntable 3 and is fixed to a chassis 8 with screws (not shown). Numeral 8a is a holding member for holding the position of the shaft 5 with respect to the chassis 8 on the inner peripheral side of the disk, such that the movement trajectory of the optical axis of the optical head 2 overlaps a straight line from the center of the disk 1 to the outer periphery. The relative position between the disk 1 and the optical head 2 is determined, and the distance in the height direction of the optical head 2 from the disk 1 is determined. Then, the shaft 5 is movably held at a slight angle (approximately ± 1 °) toward the disk 1 with the end of the shaft 5 on the inner peripheral side of the disk as a fulcrum.

A guide member 8b is mounted on the chassis 8 and guides the outer periphery of the disk of the shaft 5 so as to be movable only in a direction perpendicular to the surface of the disk 1. The guide member 8b has a substantially U shape. And is provided on the outer peripheral side of the disk 1. Reference numeral 6 denotes a leaf spring acting as the elastic member. Reference numeral 6a denotes a projection provided on the leaf spring 6, which is fitted into the fitting recess of the chassis 8 to determine the position of the leaf spring 6 with respect to the chassis 8. The leaf spring 6 is positioned near the guide member 8b and fixed to the chassis 8 with screws 9 so that the point of action acts on the axis of the shaft 5. Here, when the shaft 5 is guided to approach the chassis 8 along the substantially U-shaped guide portion of the guide member 8b, the leaf spring 6 starts to bend, and the shaft 5 is moved in a direction perpendicular to the surface of the disk 1. Energize to.

Reference numeral 10 denotes a holder, on which an inclination adjusting screw 7 is provided. The tip of the tilt adjusting screw 7 is in contact with the curved surface of the shaft 5 and thus usually has a flat tip shape. For this reason, it is common to use a screw with a hexagonal hole, and this tip abuts on the shaft 5 at a line or at one point.
The holder 10 is fixed to the chassis 8 with screws 9. Therefore, the shaft 5 includes the leaf spring 6 and the inclination adjusting screw 7.
In a state of being sandwiched by the tips of.

Here, it is desirable that the angle between the above-mentioned virtual axis of the guide hole 2a of the optical head 2 and the axis of the laser beam is a right angle.
Due to mounting error etc., it will shift about ± 0.3 °. The mounting of the disk 5 on the turntable 3 and the shaft 5 is also performed in a range of ± 0.5 to 0.
It may be shifted by about 8 °. Therefore, when the spot diameter of the laser is small and the recording density of the disk is high, the deviation of the optical head 2 itself, the deviation of the components such as the turntable 3 and the shaft 5 and the mounting error are added, and an error occurs during recording and reproduction. In some cases, the allowable value is exceeded.

Also, since the disk itself is warped, an error is likely to occur if the accuracy is low. The occurrence of errors is minimized when the axis of the laser beam of the optical head is perpendicular to the recording surface of the disk. Therefore, to minimize the occurrence of errors, tilt adjustment is performed to make the deviation between the axis of the laser beam of the optical head and the recording surface of the disk (actual adjustment is the disk mounting surface of the turntable) into an allowable range. Is required. Incidentally, since various methods of optical axis alignment are known, a description thereof will be omitted.

In the conventional tilt adjustment described with reference to FIGS. 7 to 10, the tilt adjustment screw 7 adjusts the tilt direction of the shaft 5 so as to be parallel to the disk mounting surface 3a of the turntable 3. The optical axis of the head 2 is connected to the disk mounting surface 3a of the turntable 3, that is, the disk 1
So that it is perpendicular to the plane. In this state, the optical axis deviation of the optical head itself remains. If the error is large even in this state, the above-described tilt adjustment and the like are performed while reproducing, until the jitter becomes minimum.

After the above adjustment, the tilt adjusting screw 7 and the holder 1
A screw lock material or the like is applied to the 0 screw hole to prevent the adjustment from being out of order. Here, the description of the optical head feed mechanism and the like is omitted for explanation of the optical axis correction of the optical head.

[0012]

By the way, as an optical axis correcting mechanism for an optical head with respect to a disk, a mechanism having a simpler structure, lower cost, and easier to assemble is desired.
In view of the above, it is an object of the present invention to provide an optical axis correction mechanism for an optical head having a smaller number of components than a conventional one.

[0013]

An optical axis correcting mechanism for an optical head according to the first aspect of the present invention for solving the above-mentioned problems and achieving the object described above records a signal on a disk or outputs a signal from a disk. Adjusting the inclination of a shaft that guides the optical head in the radial direction of the disk, so as to correct the optical axis of the optical head for reproducing the optical disk to be perpendicular to the disk, and attached to a chassis, A holding member for holding a position of the shaft with respect to the chassis on the inner peripheral side of the disk; and a guide member attached to the chassis for guiding the outer peripheral side of the shaft on the disk so as to be movable only in a direction perpendicular to the surface of the disk. And an elastic member for urging the disk outer peripheral side of the shaft in the movable direction and away from the chassis. Position receiving means for receiving the biased shaft and restricting a position of the shaft in the movable direction on the outer peripheral surface side of the disk, wherein the elastic member includes a plate surface of the chassis, Using a leaf spring formed by a substrate portion that is in contact with and substantially parallel to the two ends of the substrate portion and rising portions that cross each other, in the vicinity of the crossing in the rising portion of the leaf spring. The leaf spring is configured to receive the shaft, and includes a protrusion provided on one of the leaf spring and the chassis and a concave portion provided on either the chassis or the leaf spring to which the protrusion is fitted. The position with respect to the chassis is determined.

[0014] The elastic member is formed by a substrate portion in contact with the chassis surface so as to be substantially parallel to the chassis surface and a rising portion inclined from both ends of the substrate portion so as to cross each other. A board portion that is in contact with the chassis so as to be substantially parallel to the board surface, and a second rising portion that is raised substantially perpendicularly and in the same direction from both ends of the board portion. And using a leaf spring formed by a rising portion formed by a falling portion inclined and lowered so as to cross each other from the tip of the second rising portion toward the plate surface of the substrate portion. You may.

Further, a screw which is screwed to the chassis and has a contact portion with which the urged shaft comes into contact may be used as the position restricting means. A screw with a washer to which the biased shaft is brought into contact may be used.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. In FIGS. 1 to 4, unless otherwise specified, FIG.
The same reference numerals as those shown in FIGS.
1 to 4, the optical head 2 is provided with a guide hole 2a and a guide portion 2b in the same manner as in the conventional example. A shaft 5 penetrates the guide hole 2a, and guides the optical head 2 in the radial direction of the disk 1. The direction of the laser beam emitted from the optical head 2 is the guide hole 2
It is designed to be perpendicular to a virtual axis passing through a. However, it is the same as the conventional one that a certain degree of inclination occurs due to dimensional error of assembly or parts.

The spindle motor 4 is provided with a turntable 3 and is fixed to a chassis 8 with screws (not shown). 8a is a holding member described in the above-mentioned conventional example, and 8b is a guide member. Reference numeral 11 denotes a leaf spring acting as an elastic member in the conventional example, which is inclined and rises so as to cross each other from both ends of the substrate portion which is in contact with the plate surface of the chassis 8 so as to be substantially parallel to the plate surface. The base portion has a substantially X-shape, and the lower side has an integral shape connected at both ends of the substrate portion. Reference numeral 11a denotes a projection, which is fitted into the positioning fitting concave portion of the chassis 8, and the leaf spring 11 is positioned on the chassis 8.

The leaf spring 11 is positioned near the guide member 8b such that the intersection of the substantially X-shape coincides with the vertical movement direction of the axis of the shaft 5. Here, the leaf spring 11 is not fixed to the chassis 8 but is merely positioned. The shaft 5 is a guide member 8
When guided by the substantially U-shaped guide portion b and approaches the chassis 8, the leaf spring 11 starts to bend and urges the shaft 5 in a direction perpendicular to the surface of the disk 1.

Reference numeral 12 denotes a tilt adjusting screw having a flange. The screw 12 is directly screwed and attached to the chassis 8. Therefore, the shaft 5 is connected to the leaf spring 11.
And the inclination adjusting screw 12 is sandwiched between the flanges. To adjust the tilt, the tilt adjusting screw 12 is used to adjust the tilt direction of the shaft 5 to the disk mounting surface 3 of the turntable 3.
a to adjust the optical axis of the optical head 2 to the disk mounting surface 3a of the turntable 3, ie, the disk 1
So that it is perpendicular to the plane. Incidentally, in this state, the optical axis deviation of the optical head 2 itself remains as in the conventional example.
If the error is still large in this state, the inclination is adjusted while reproducing the signal until the jitter becomes the minimum.

After this adjustment, a screw lock material or the like is applied to the inclination adjusting screw 12 and the screw hole of the chassis 8 so that the adjustment is not disturbed. Therefore, compared with the conventional example, a fixing screw for the leaf spring is not required, a holder for fixing the inclination adjusting screw, a screw, and the like are not required, and the number of parts can be reduced.

Instead of the leaf spring 11 of the above embodiment, FIG.
Alternatively, a leaf spring 13 shown in FIG. 6 may be used. The leaf spring 13 includes a substrate portion that is in contact with the chassis 8 so as to be substantially parallel to the plate surface, a second rising portion that is raised substantially vertically and in the same direction from both ends of the substrate portion, The second rising portion is formed by a falling portion which is inclined and lowered so as to cross each other from the tip of the second rising portion toward the plate surface of the substrate portion.

In the above-described embodiment of the present invention, the inclination adjusting screw having a flange is used, but the same effect can be expected by using a screw with a washer or the like. Also, using a conventional hexagon socket screw as a tilt adjusting screw,
Even if it is combined with 0, the fixing screw of the leaf spring is not necessary,
There is an effect that it is easy to assemble. Further, the leaf springs 11 and 13
May be provided on the chassis 8 and fitting recesses into which the protrusions are fitted may be provided on the leaf springs 11 and 13.

[0023]

Since the present invention is constructed as described above, the number of parts is smaller than that of the prior art, and only the leaf spring needs to be mounted on the chassis. This leaf spring has an approximately X shape or M shape. Due to the shape, when the shaft is mounted, a reaction force toward the chassis acts on the connecting portion, that is, the above-described substrate portion, and the substrate portion comes into close contact with the chassis, thereby improving the workability of assembling without tilting.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an embodiment of the present invention.

FIG. 2 is a schematic exploded perspective view showing one embodiment of the present invention.

FIG. 3 is a schematic sectional view showing an embodiment of the present invention.

FIG. 4 is a schematic sectional view showing one embodiment of the present invention, which is before adjustment different from FIG. 3;

FIG. 5 is a schematic perspective view showing another embodiment of the present invention.

FIG. 6 is a schematic exploded perspective view showing another embodiment of the present invention.

FIG. 7 is a schematic perspective view showing a conventional example.

FIG. 8 is a schematic exploded perspective view showing a conventional example.

FIG. 9 is a schematic sectional view showing a conventional example.

FIG. 10 is a schematic sectional view showing a conventional example, which is before adjustment different from FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Disc 2 Optical head 2a Guide hole 2b Guide part 3 Turntable 3a Disk mounting surface 4 Spindle motor 5 Shaft 6 Leaf spring 6a is protruded 7 Tilt adjusting screw 8 Chassis 8a Holding member 8b Guide member 9 Screw 10 Holder 11 Leaf spring 11a Protrusion 12 tilt adjusting screw 13 leaf spring 20 disk clamper

Claims (5)

[Claims] 1. An inclination of a shaft for guiding an optical head in a radial direction of the disk so as to correct an optical axis of the optical head for recording a signal on the disk or reproducing a signal from the disk so as to be perpendicular to the disk. A holding member attached to a chassis, for holding a position of the shaft with respect to the chassis on the inner peripheral side of the disk, and a retaining member attached to the chassis, the outer peripheral side of the shaft being the surface of the disk. A guide member for movably guiding only in the direction perpendicular to the shaft, an elastic member for urging the disk outer peripheral side of the shaft so as to move away from the chassis in the movable direction, and The shaft is received, and the position of the shaft in the movable direction on the outer peripheral surface side of the disk is defined. A position restricting means, wherein the elastic member includes a substrate portion contacting so as to be substantially parallel to a plate surface of the chassis, and a rising portion raised from both ends of the substrate portion and crossing each other. The formed leaf spring is used to receive the shaft in the vicinity of the cross at the rising portion of the leaf spring, and the projection provided on one of the leaf spring and the chassis is fitted with the projection. An optical axis correction mechanism for an optical head, wherein a position of the leaf spring with respect to the chassis is determined by a concave portion provided in either the chassis or the leaf spring. 2. The elastic member is formed by a substrate portion in contact with the chassis surface so as to be substantially parallel to the chassis surface, and a rising portion inclined from both ends of the substrate portion so as to cross each other. 2. The optical axis correcting mechanism for an optical head according to claim 1, wherein a leaf spring is used. 3. A substrate portion as said elastic member, which is in contact with the chassis surface so as to be substantially parallel to the chassis, and a second rising portion which is raised substantially perpendicularly and in the same direction from both ends of the substrate portion. And a leaf spring formed by a rising portion having a falling portion inclined down from the tip of the second rising portion so as to cross each other toward the plate surface of the substrate portion. An optical axis correction mechanism for an optical head. 4. A screw, which is screwed to the chassis and has a contact portion with which the urged shaft comes into contact, is used as the position restricting means.
An optical axis correction mechanism for an optical head according to any one of claims 1 to 3. 5. A screw according to claim 1, wherein said position restricting means is a screw with a washer screwed to said chassis and abutted against said biased shaft. An optical axis correction mechanism for an optical head according to the above.