JPH09320090A - Optical pickup - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize more accurate adjustment without bringing a movable part and a cover into contact with each other by integrally forming the movable part which moves in angle during angular adjustment of the optical axis of an objective lens and the cover. SOLUTION: When a tangential skew to the main point on the focusing point side of an objective lens 21 and a disk surface is adjusted in the direction C, a left side adjusting screw 45 at the v-shaped fulcrum point 32 of a yoke 30 is rotated in such a direction that it is removed from the screw hole 31. Simultaneously, the right side adjusting screw 45 is rotated in the screwing direction. Thereby, the yoke 30 is inclined around the fulcrum point 32 in the direction D and an objective lens 21 of the movable part 20 held by a wire 25 to the yoke 30 is also inclined in the direction D to adjust the tangential skew. Moreover, in this case, the cover 50 fixed to the yoke 30 changes the angular synchronously with the movable part 20. As explained, since the cover 50 is fixed to the yoke 30 of the movable part 20, the cover 50 synchronously moves for a certain angle during adjustment of the angle of the movable part 20. Accordingly, the movable part 20 and cover 50 does not contact and disabling of reproduction due to the short circuit can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the shape and mounting structure of a cover of an optical pickup for reading and reproducing a recording signal of an optical disc.

[0002]

2. Description of the Related Art In an optical disk player using an optical disk as a recording medium, an optical pickup is used as means for reading and reproducing information signals recorded on the disk. The optical pickup converges a laser beam emitted from a laser light source as a beam spot on a signal recording surface of an optical disc into a pit row, which is a minute irregularity, as a beam spot through an objective lens, and is reflected from the pit row. An information signal is read and reproduced by detecting the state of the reflected beam with a photodetector.

By the way, when the laser beam is focused on the pit train of the optical disc through the objective lens as a beam spot, the optical axis of the objective lens is maintained accurately and perpendicular to the signal recording surface of the optical disc. If not, an aberration occurs in the beam spot focused on the pit row, a noise component is superimposed on the information signal to be read and reproduced, and the reproduction characteristic is deteriorated, or the reading and reproduction of the information signal becomes impossible depending on the degree. is there. Therefore, an optical pickup used in an optical disc player or an optical recording / reproducing apparatus records the laser beam onto the signal recording surface of the optical disc so that the laser beam always enters the signal recording surface of the optical disc accurately and perpendicularly. Various types are used that are provided with a mechanism for adjusting the inclination of the optical axis of an objective lens that focuses light on a surface.

An example of a conventional optical pickup will be described with reference to FIG. FIG. 5 is an internal front view showing the outline of the configuration of a conventional optical pickup. 100 is an optical pickup,
The movable portion 110, the yoke 120, the base 130, the adjusting screw 140, the wire 150, the optical pick cover 160, and the like are included.

The movable portion 110 has an objective lens 111 (held by a lens holder 113) for focusing a laser beam on a signal recording surface of an optical disk and a magnetic coil (not shown) fixed to a resin member. The movable part 110 is elastically held by the yoke 120 by four elastic bodies, two of which are fixed to each of the two side parts, for example, a wire 150 having an extremely small diameter of phosphor bronze.

The yoke 120 has an L-shape, and has a fixed portion 121 of a wire 150 elastically holding the movable portion 110 in the vertical direction, and a tangential skew of the objective lens 111 in the horizontal direction. The screw hole 123 into which the adjusting screw 140 for adjusting the tilt angle in the vertical direction is screwed, and the V-shaped fulcrum 122 serving as the fulcrum of the seesaw operation when adjusting the tangential skew.
Are formed. The yoke 120 engages with the coil of the movable portion 110 to form a magnetic circuit (not shown).

The base 130 is the base portion of the optical pickup 100, and has a screw hole 131 and the like into which an adjusting screw 140 for adjusting the tangential skew is screwed.
The optical pickup cover (hereinafter referred to as cover) 160 is
A hole 161 having a lid shape and through which a beam of light passes is formed. The cover 160 is provided on the movable portion 110 and is held so as to cover the base 130. A thin steel plate or the like is used as the material of the cover 160 and is formed by press working or the like.

Next, the operation of adjusting the tangential skew will be described. When adjusting the tangential skew between the principal point 112 of the objective lens 111 on the image point side and the surface of the disk 170, for example, in the E direction, V of the yoke 120 is adjusted.
Adjust the adjustment screw 140 on the left side of the fulcrum 122 in the shape of a yoke 12
When the adjusting screw 140 on the right side is turned in the direction of being screwed into the screw hole 123 of the yoke 120 at the same time as being turned in the direction of coming out of the screw hole 123 of 0, the V-shaped fulcrum 122 of the yoke 120 is obtained.
With the fulcrum as the fulcrum, the yoke 120 tilts in the F direction,
The objective lens 111 of the movable part 110 held by the wire 150 at 0 is tilted in the E direction and the tangential skew is adjusted. When adjusting in the direction opposite to the E direction, the operations of the left adjusting screw 140 and the right adjusting screw 140 may be reversed from those in the E direction.

[0009]

However, in the above-described optical pickup 100, when adjusting the angle of the optical axis of the objective lens, there are a moving part (movable part) and a non-moving part (base part), and the cover is used. 160 is fixed toward the base portion. Moreover, since the two parts of the movable part and the base part are arranged so as to overlap each other over substantially the whole, particularly in the thin optical pickup 100, when the angle is adjusted, the lens holder 113, the actuator, and the suspension which are formed in the movable part are adjusted. A pencil or the like may interfere with the cover 160. If the cover 160 is a conductor and the actuator is a 4-wire system that energizes the suspension, a short-circuit problem may occur, or the movable range in the focus direction and the tracking direction may be limited. In addition, when vibration is applied from the outside, the movable part 110 and the cover 160 may interfere with each other to cause a problem such as unreadable data.

Therefore, the present invention solves the above-mentioned problems, and an object of the present invention is to provide an optical pickup in which the movable portion that moves angularly when the angle of the optical axis of the objective lens is adjusted does not interfere with the cover.

[0011]

SUMMARY OF THE INVENTION The present invention achieves the above-mentioned object, and a movable part for holding an objective lens and a magnetic circuit part, and an angle adjustment for holding the movable part in a base part so that the angle can be adjusted. And a cover for covering the optical pickup, the cover covering the optical pickup being provided so as to move in synchronization with the angle adjustment of the movable portion.

Further, the support portion of the cover is fixed to the movable portion. Further, a holding portion is provided in the magnetic circuit portion, and a supporting portion of the cover is fixed to the holding portion. Further, the support portion of the cover is formed of an elastic member.

Further, the cover is integrally formed of an elastic member forming a support portion.
Further, the invention is characterized in that an insertion guide portion is provided at a tip end portion of the claw. Further, in the plane parallel to the optical disc, the center of gravity of the cover is arranged in a region surrounded by the supporting portion of the cover.

Further, in the plane parallel to the optical disc, all the supporting portions of the cover are arranged in either one of the two areas divided by a straight line on the locus drawn by the center of gravity of the objective lens. It is characterized by that.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a front view showing the outline of the configuration of the optical pickup of the first embodiment of the present invention. 10 is an optical pickup,
Movable part 20, yoke 30, base 40, adjusting screw 45,
The wire 25 and the cover 50 are included.

The movable portion 20 has an objective lens 21 (held by a lens holder 22) for focusing a laser beam on a signal recording surface of an optical disk and a magnetic coil (not shown) fixed to a resin member. The movable portion 20 is elastically held by the yoke 30 by four elastic bodies, two of which are fixed to each of the two side portions, for example, a wire 25 having an extremely small diameter of phosphor bronze. The movable portion 20 needs to adjust the tilt of the optical axis of the objective lens 21 that focuses the laser beam on the signal recording surface of the optical disc so that the laser beam always enters the signal recording surface of the optical disc accurately and vertically. Is. still,
The shape and material of the movable portion 20 are selected so as to reduce the overall weight.

The yoke 30 is U-shaped, and the wire 25 elastically holding the movable portion 20 and the support portion 51 of the cover 50 are fixed to one side (right side in the drawing) in the vertical direction.
The supporting portion 51 of the cover 50 is screwed and fixed to the other side (the left side in the drawing). Further, in the horizontal direction (bottom part), an adjusting screw 45 for adjusting the tangential skew of the objective lens 21 (the tilt angle of the tangential direction of the disk) is provided.
Are formed, and a V-shaped fulcrum 32 that serves as a fulcrum of the seesaw operation when adjusting the tangential skew. The yoke 30 engages with the coil of the movable portion 20 to form a magnetic circuit (not shown).

The base 40 is the base portion of the optical pickup 10 and is an adjusting screw 4 for adjusting the tangential skew.
A screw hole 41 and the like into which 5 is screwed are formed. Cover 5
0 is 2 on each side of the ceiling 52 and the ceiling 52.
Four supporting portions 51 are formed one by one, a hole 53 through which a beam of light passes, and a supporting portion 5 at the ceiling portion 52.
A hole for attaching to the yoke 30 is formed at the tip of the No. 1. The cover 50 is provided on the upper part of the movable part 20 and moves angularly in synchronization with the movable part 20 when adjusting the angle of the movable part 20. A thin steel plate having elasticity is used as the material of the cover 50, and is formed by press working or the like.

Next, the adjustment of the angle (tangential skew) of the movable portion will be described. When adjusting the tangential skew between the image point side principal point 23 of the objective lens 21 and the surface of the disk, for example, in the C direction, the yoke 30 is used.
Adjustment screw 45 on the left side of the V-shaped fulcrum 32 of
When the adjusting screw 45 on the right side is turned in the direction of being screwed into the screw hole 31 of the yoke 30 at the same time as turning the screw 30 in the direction of coming out of the screw hole 31, the yoke 30 moves in the D direction with the V-shaped fulcrum 32 of the yoke 30 as a fulcrum. The tilt, the objective lens 21 of the movable part 20 held by the wire 30 on the yoke 30 tilts in the D direction, and the tangential skew is adjusted. At this time, the angle of the cover 50 fixed to the yoke 30 also changes in synchronization with the movable portion 20. When adjusting in the direction opposite to the C direction, the operations of the left adjusting screw 45 and the right adjusting screw 45 may be reversed from those in the C direction.

As described above, according to this embodiment,
Since the cover 50 is fixed to the yoke 30 of the movable part 20, the cover 50 synchronously moves when the angle of the movable part 20 is adjusted, so that the movable part 20 and the cover 50 do not interfere (contact) with each other. Therefore, it is possible to prevent problems such as reproduction failure due to a short circuit. Next, a second embodiment of the present invention will be described with reference to FIG.

2A and 2B are schematic views showing the structure of an optical pickup according to a second embodiment of the present invention. FIG. 2A is a front view, FIG. 2B is a sectional view taken along line AA, and FIG. 2C is a sectional view taken along line BB. It is a figure. The second
In the embodiment, a part of the cover of the first embodiment is modified, and other parts are substantially the same as the structure of the first embodiment, and therefore, the same components are denoted by the same reference numerals and the description thereof will be omitted.

Reference numeral 50 denotes a cover, which is a ceiling portion 52 and a ceiling portion 52.
Four supporting portions 51 are formed on each side of each of the two portions, and two holes are formed in each of the two portions. Holes 53 through which beam rays pass are attached to a ceiling portion 52, and a yoke 30 is attached to a tip portion of the supporting portion 51. A claw 54 that engages with the hole 34 of the holding portion 33 is formed inward (right angle direction), and a tip end portion of the claw 54 is provided with a guide portion 55 having a substantially arc shape so that it can be easily inserted into the hole 34. There is. It should be noted that the tips of the supporting portions 51 are formed to be slightly recessed inward, and the claws 54 are formed in the holes 3 of the holding portion 33.
A force for sandwiching the holding portion 33 is applied when the holding portion 33 is locked in the position 4. The cover 50 is provided on the movable part 20,
When the angle of the movable portion 20 is adjusted, the movable portion 20 is angularly moved in synchronization with the movable portion 20. A thin steel plate having elasticity is used as the material of the cover 50, and is formed by press working or the like.

The holding portion 33 is screwed to both sides of the yoke 30 at the mounting portion of the cover 50, and has a hole 34 in which a claw 54 of the cover 50 is locked. As described above, in the present embodiment as well, the cover 50 moves angularly in synchronization when the angle of the movable portion 20 is adjusted as in the first embodiment, so that the movable portion 20 and the cover 50 interfere (contact) with each other.
Therefore, it is possible to prevent a problem such as a reproduction failure due to a short circuit. Besides, since the cover 50 is fixed by inserting the claw 54 of the cover 50 into the hole 34 of the holding portion 33, the cover 50 is easily mounted.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 3 is a plan view showing the positional relationship of the cover support portion of the optical pickup of the third embodiment of the present invention. Incidentally, the third embodiment limits the mounting position of the cover of the first embodiment, and since the other parts are substantially the same as the structure of the first embodiment, the same components are designated by the same reference numerals and will not be described. Omit it.

The formation position e of the support portion 51 of the cover 50,
In f, g, and h, the center of gravity 56 of the entire cover 50 is e,
It is provided at a position so as to be configured within a region surrounded by four diagonal lines of f, g, and h. As described above, in the present embodiment, the position of the center of gravity 56 of the cover 50 is formed within the area surrounded by the four shaded lines e, f, g, h of the support portion 51 of the cover 50. Therefore, problems such as the cover 50 fluttering due to vibration are reduced. Therefore, it is less likely to be affected by external vibration, and stable reproduction or recording is possible.

Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 4 is a plan view showing the positional relationship of the cover support portion of the optical pickup of the fourth embodiment of the present invention. Incidentally, the fourth embodiment limits the mounting position of the cover of the first embodiment, and since the other parts are substantially the same as the structure of the first embodiment, the same reference numerals will be given to the same structures for the description. Omit it.

The formation position i of the support portion 51 of the cover 50,
One of j, k, and l includes a boundary line (straight line 24), which is a region bisected by a straight line 24 on the locus drawn by the center of gravity of the objective lens tracing from the inner circumference to the outer circumference of the optical disk (for example, All the support parts 51 of the cover 50 are formed in the area of the right side of the drawing. It should be noted that in the other (left side in the figure) area, a component other than the cover configured in the optical pickup 10, for example, a PC board or the like may be provided so as to also serve as the cover.

As described above, in this embodiment,
Even if the fulcrum of the angle adjustment of the movable part of the optical axis of the objective lens 21 exists near the center of gravity of the objective lens 21, it is possible to prevent the cover 50 from interfering with the surface of the medium (disk) during the angle adjustment. it can.

[0029]

As described above, according to the present invention, the movable portion and the cover, which move angularly when the angle of the optical axis of the objective lens is adjusted, are integrally formed, so that part of the movable portion serves as the cover. The problem of interference disappears. Further, since it is not necessary to limit the movable range of the movable portion and the adjustment range can be widened, more accurate adjustment can be performed. In addition, it is possible to prevent the problem that the movable portion and the cover interfere with each other against external vibration.

[Brief description of drawings]

FIG. 1 is a front view showing the outline of the configuration of an optical pickup according to a first embodiment of the present invention.

2A and 2B are schematic views showing the configuration of an optical pickup according to a second embodiment of the present invention, in which FIG. 2A is a front view, FIG. 2B is an AA sectional view, and FIG. 2C is a BB sectional view. is there.

FIG. 3 is a plan view showing a positional relationship of a cover support portion of an optical pickup according to a third embodiment of the present invention.

FIG. 4 is a plan view showing a positional relationship of cover support portions of an optical pickup according to a fourth embodiment of the present invention.

FIG. 5 is a front view showing a schematic configuration of a conventional optical pickup.

[Explanation of symbols]

 10-Optical pickup 20-Movable part 21-Objective lens 22-Lens holder 23-Image point side principal point 24-Line 30 ... Yoke 31, 41 ... Screw hole 32 ... Support point 33 ... Holding part 34, 53 ... Hole 40 ... Base 45 ... Adjusting screw 50 ... Cover 51 ... Support 52 ... Ceiling 54 ... Claw 55 ... Guide 56 ... Center of gravity

Claims (9)

[Claims] 1. An optical pickup for reading and reproducing a recording signal of an optical disc, comprising: a movable part that holds an objective lens and a magnetic circuit part; and an angle adjusting part that holds the movable part in a base part so that the angle can be adjusted, An optical pickup, wherein a cover covering the optical pickup is provided so as to move in synchronization with an angle adjustment of the movable portion. 2. The optical pickup according to claim 1, wherein a support portion of the cover is fixed to the movable portion. 3. The optical pickup according to claim 1, wherein a holding portion is provided in the magnetic circuit portion, and a supporting portion of the cover is fixed to the holding portion. 4. The optical pickup according to claim 2, wherein the support portion of the cover is formed of an elastic member. 5. The optical pickup according to claim 1, wherein the cover is integrally formed of an elastic member forming a support portion. 6. A locking claw formed so as to project inward at the tip of the support part, and a hole for locking the locking claw formed in the yoke of the magnetic circuit part. The optical pickup according to claim 1 or 2, wherein the locking claw is locked in the hole. 7. The optical pickup according to claim 6, wherein an insertion guide portion is provided at a tip portion of the claw. 8. In a plane parallel to the optical disc,
3. The optical pickup according to claim 1, wherein the center of gravity of the cover is arranged in a region surrounded by a supporting portion of the cover. 9. In a plane parallel to the optical disk,
3. All the supporting portions of the cover are arranged in one of the two areas divided by a straight line on the locus drawn by the center of gravity of the objective lens. Optical pickup.