JP3665214B2 - Optical pickup - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical pickup used for a compact disc (CD) player, a mini disc (MD) player, a digital versatile disc (DVD) player, and the like, and more particularly, a skew for adjusting the inclination of the optical axis of an objective lens. It relates to an adjustment mechanism.
[0002]
[Prior art]
In general, in an optical pickup, an optical axis of a light beam irradiated through an objective lens is maintained at a right angle to a recording surface of a disc, and a beam spot focused on the recording surface is made circular. A skew adjustment mechanism is provided.
A conventional optical pickup skew adjustment mechanism will be described below with reference to FIGS. 4 and 5. FIG. 4 is a plan view showing a conventional optical pickup, and FIG. 5 is a side view showing the optical pickup partially in cross section.
[0003]
Reference numeral 1 in the figure denotes an objective lens formed of a synthetic resin or a glass material, and is bonded and fixed to one end of the lens holder 2. Free end portions of a pair of support members 3 and 3 are fixed to both side portions of the lens holder 2, respectively. Each support member 3 is formed of a metal linear spring that is elastically deflectable and deformable in any direction and has conductivity, and the base ends of all the support members 3, 3,. 4 is fixed by soldering.
[0004]
In addition, a square hole 2a is formed in a substantially central portion of the lens holder 2 so as to penetrate in the focus direction (arrow F direction), and a square cylindrical focus coil 5 is bonded to the inner surface of the square hole 2a. Further, a pair of tracking coils 6 and 6 are bonded and fixed on one side surface of the focus coil 5. The ends of the focus coil 5 and tracking coil 6 are electrically connected to the free ends of the support members 3, 3,... A current is supplied to the focus coil 5 and the tracking coil 6 through.
[0005]
The printed circuit board 4 is bonded and fixed to the back surface of the suspension base 7 made of synthetic resin. As shown in FIG. 4, the suspension base 7 is formed with through holes 7a and 7a. The support member 3 described above is inserted into each through hole 7a, and further, a gel-like damping material is filled in the through hole 7a. Thereby, it is possible to prevent the support members 3, 3,... From resonating due to external vibration or the like acting on the lens holder 2.
[0006]
The suspension base 7 is fixed on a yoke base 8 formed by pressing a metal plate. A magnetic circuit composed of a U-shaped yoke 9 and a pair of magnets 10 and 10 fixed to the inner surfaces of both standing pieces 9 a and 9 a of the yoke 9 is attached to the upper surface of the yoke base 8. Yes. One side surface of the tracking coil 6, 6 and the focus coil 5 to which the tracking coil 6, 6 is attached is inserted into a magnetic gap between the magnets 10, 10. The lens holder 2 is driven in the focus direction and the tracking direction (arrow T direction) by electromagnetic force generated by the current flowing through the coils 5 and 6.
[0007]
The yoke base 8 is integrally formed with a spherical projecting portion 8a on the optical axis L of the objective lens 1 by pressing. The center of the spherical surface of the projecting portion 8a is made to coincide with the center of the objective lens 1. Further, the yoke base 8 is provided with a screw hole 8b below the protrusion 8a in FIG. 4 and a screw hole 8c on the right side of the protrusion 8a. The center of the screw hole 8b is located in a plane extending in the tracking direction through the optical axis L of the objective lens 1, and the center of the screw hole 8c is perpendicular to the tracking direction through the optical axis L of the objective lens 1. Located in a plane extending to
[0008]
The yoke base 8 is mounted on an optical chassis 13 made of aluminum die cast by one fastening screw 11 and a pair of adjustment screws 12a and 12b. The end of the fastening screw 11 is inserted into a through hole (not shown) of the yoke base 8 and screwed into a screw hole of the optical chassis 13. A coil spring 14 is provided around the fastening screw 11 to provide a coil spring 14. The yoke base 8 is pressed against the optical chassis 13 side. On the other hand, the adjustment screw 12a is screwed into the screw hole 8b of the yoke base 8 from the bottom surface side of the optical chassis 13, and the adjustment screw 12b is similarly screwed into the screw hole 8c of the yoke base 8 from the bottom surface side of the optical chassis 13.
[0009]
On the upper surface of the optical chassis 13, an annular spherical seat 13 a is formed on the optical axis L of the objective lens 1. The radius of curvature of the spherical seat 13a is equal to the radius of curvature of the protruding portion 8a of the yoke base 8. Then, by rotating one adjustment screw 12a with the protruding portion 8a fitted to the spherical seat 13a, the protruding portion 8a rotates while sliding on the spherical seat 13a, and the optical chassis of the yoke base 8 is rotated. The mounting angle with respect to 13 is varied, and skew adjustment in the radial direction of the optical axis L of the objective lens 1 is performed. Similarly, the skew adjustment in the tangential direction of the optical axis L of the objective lens 1 is performed by rotating the other adjustment screw 12b.
[0010]
[Problems to be solved by the invention]
By the way, in the above-described conventional optical pickup, the angle of the yoke base 8 with respect to the optical chassis 13, that is, the skew adjustment of the optical axis L of the objective lens 1 is performed by sliding between the spherical annular protrusion 8 a and the spherical seat 13 a. Therefore, in order to perform smooth skew adjustment work, it is necessary to increase the processing accuracy of the projecting portion 8a and the spherical seat 13a, which are sliding portions, and to reduce the roughness of the surface. There is a problem that not only the mold for molding becomes expensive but also a cutting process is required, resulting in an increase in manufacturing cost.
[0011]
Further, in the above-described conventional skew adjustment mechanism, the spherical annular protrusion 8a and the spherical seat 13a are shared as the rotation center at the time of skew adjustment in the radial direction and the tangential direction, and the protrusion 8a is seamless. Since it is configured to rotate in the radial direction and tangential direction, there is a possibility that the skew angle in the other direction may slightly shift during skew adjustment in one direction. Therefore, the skew adjustment work in the radial direction and tangential The direction skew adjustment work cannot be performed independently, and there is a problem that it is difficult to automate these adjustment work.
[0012]
The present invention has been made in view of the above problems, and has as its main object to provide an optical pickup capable of simplifying the skew adjustment mechanism and reducing the manufacturing cost.
[0013]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides an objective lens that converges a light beam emitted from a light source on a signal recording surface of a disk, a lens holder that holds the objective lens, and the lens holder via a support member. An optical pickup having a base member that is movably supported in a focusing direction and a tracking direction, and a chassis to which the base member is attached so as to be adjustable in angle.
Wherein the base member, the support pieces have a said center twist deformable hinge portion about an axis through extending in the tracking direction of the position and and the objective lens on both sides of the objective lens in the tracking direction is provided, this the support piece, the folded form of the metal plate with provided integrally with the base member, the free end side is fixed by a screw on the shaft against the chassis, between the base member and the chassis Is provided with an adjusting mechanism for rotating the base member about the hinge portion to adjust the inclination of the optical axis of the objective lens in the tangential direction.
[0014]
According to the above configuration, the hinge portion that can be torsionally deformed about the axis that extends in the tracking direction through the center of the objective lens is provided, and the skew adjustment in the tangential direction is performed by rotating the base member around the hinge portion. Since it can be performed, the conventional spherical ring-shaped protrusion and spherical seat are not required, and the manufacturing cost can be reduced.
[0015]
The said structure WHEREIN: It is preferable that the support piece which has a hinge part is integrally provided in the base member by bending formation of the metal plate.
With this configuration, it is possible to reduce the number of parts and to provide a cheaper optical pickup.
[0016]
Moreover, in the said structure, it is preferable that the free end part of a support piece is being fixed to the chassis with the fixing screw on the axis | shaft which passes along the center of a hinge part. With this configuration, when a torsional stress is applied to the hinge portion of the support piece, the portion between the hinge portion and the free end portion can be prevented from being undesirably deformed, and the skew angle in the radial direction can be prevented. The skew adjustment in the tangential direction can be reliably performed without affecting the above.
[0017]
In the above configuration, it is preferable that the adjustment mechanism has an adjustment screw whose rotation center is located in a plane that includes the optical axis of the objective lens and is orthogonal to the tracking direction. According to this configuration, when the adjustment screw is rotated, equal torsional stress is applied to the pair of hinge portions located on both sides of the objective lens in the tracking direction, so that the tangential is not affected without affecting the skew angle in the radial direction. Direction skew adjustment can be performed reliably.
[0018]
Further, in the above configuration, the support member has a free end side fixed to the lens holder and a base end side fixed to the substrate, respectively, and the substrate extends in a direction orthogonal to both the focus direction and the tracking direction. It is preferable that it is attached to the base member so as to be rotatable around the portion.
According to this structure, the skew adjustment in the radial direction can be performed independently and easily separately from the skew adjustment in the tangential direction by rotating the substrate on which the base end side of the support member is fixed. Thus, each skew adjustment operation can be automated.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of an optical pickup according to the present invention will be described with reference to the drawings. In addition, about the structure same as the prior art mentioned above, the same code | symbol shall be attached | subjected and detailed description shall be omitted.
1 is a plan view of an optical pickup according to the present invention, FIG. 2 is a side view showing the optical pickup in a partial cross section, and FIG. 3 is a cross-sectional view taken along line AA in FIG.
[0020]
The free ends (the left end in FIG. 1) of the support members 3, 3,... Made of conductive metal linear springs are fixed to both sides of the lens holder 2 that holds the objective lens 1. Yes. The base end portions (right end portions in FIG. 1) of the support members 3, 3,... Are soldered to the printed circuit board 4, and the lens holder 2 is moved in the focus direction (arrows) by the bending deformation of the support members 3, 3,. F direction) and tracking direction (arrow T direction).
The focus coil 5 and the tracking coils 6, 6 attached to the lens holder 2 are electrically connected to the support members 3, 3,... Current is supplied to the focus coil 5 and the tracking coil 6 through.
[0021]
A through hole (not shown) is formed in the central portion of the printed circuit board 4, and the fixing screw 21 inserted through the through hole is screwed into the screw hole 7 b on the back surface of the suspension base 7, whereby the printed circuit board 4. Is fixed to the suspension base 7. As shown in FIG. 1, the rotation center of the fixing screw 21 extends through the optical axis L of the objective lens 1 in a direction perpendicular to the tracking direction (the left-right direction in the drawing). Therefore, the fixing screw 21 is loosened to fix this. By rotating the printed circuit board 4 using the screw 21 as a rotation shaft, skew adjustment in the radial direction (r direction in FIG. 3) of the optical axis L of the objective lens 1 can be performed.
[0022]
The suspension base 7 is bonded and fixed on a yoke base 22 that is bent from a metal plate by press working. The suspension base 7 and the yoke base 22 support the lens holder 2 with support members 3, 3,. A base member is configured to be supported so as to be movable in the focus direction and the tracking direction. A yoke 9 formed in a U shape from a magnetic material is fixed to the upper surface of the yoke base 22, and magnets 10 and 10 are attached to the inner surfaces of both standing pieces 9 a and 9 a of the yoke 9 to form a magnetic circuit. Has been. The yoke 9 may be formed integrally with the yoke base 22 by punching and bending the yoke base 22.
[0023]
The tracking coils 6 and 6 and one side surface of the focus coil 5 to which the tracking coils 6 and 6 are attached are arranged in a magnetic gap between the magnets 10 and 10. The lens holder 2 is driven in the focus direction and the tracking direction by the electromagnetic force generated from the current flowing through the coils 5 and 6.
[0024]
As shown in FIG. 3, the yoke base 22 is integrally provided with support pieces 22 a and 22 a that are bent in an L shape in the vicinity of the objective lens 1. Each support piece 22a includes a vertical portion 22b extending in the focus direction, and a horizontal portion 22c extending in the tracking direction continuously to the vertical portion 22b, and a narrow hinge portion 22d at the approximate center of the horizontal portion 22c. (See FIG. 1) is formed. The horizontal portion 22c can be twisted around the hinge portion 22d.
[0025]
The hinge portions 22d and 22d are located on both sides of the objective lens 1 in the tracking direction, and the hinge portions 22d and 22d are twisted and deformed around an axis O passing through the center of the objective lens 1 and extending in the tracking direction. It is possible. The center of the objective lens 1 here means a range between the image side principal point H1 and the light source side principal point H2 (see FIG. 3) in a plane including the optical axis L and extending in the tracking direction. Through holes 22g are formed in the horizontal portions 22c of the support pieces 22a and 22a, respectively, and fixing screws 23 are inserted into the through holes 22g, and the free ends of the support pieces 22a and 22a are placed on the axis O. Is fixed to an optical chassis 25 described later.
[0026]
Further, the yoke base 22 is integrally formed with an adjustment piece 22e by bending the right end in FIG. 2 into an L shape. A screw hole 22f is formed in the adjustment piece 22e as shown in FIG. The center of the screw hole 22f is located on a plane including the optical axis L of the objective lens 1 and extending in a direction orthogonal to the tracking direction.
[0027]
The optical chassis 25 is made of aluminum die cast, and both sides thereof are guided by a pair of guide shafts 26 and 26 so as to be reciprocally movable in the radial direction of a disk D (see FIG. 3) as a recording medium. ing. A light receiving / emitting module 27 in which a semiconductor laser that is a light source and a light receiving element are integrated is embedded in the left side surface of the optical chassis 25 in FIG. 1, and the light receiving / emitting surface side of the light receiving / emitting module 27 is embedded. A through hole 25a is formed in a portion corresponding to the above.
[0028]
The light beam emitted from the light receiving / emitting module 27 passes through the through-hole 25a, is reflected toward the objective lens 1 by a reflection mirror (not shown), and the beam spot transmitted through the objective lens 1 and converged is a signal of the disk D. Irradiates the recording surface. The light beam reflected by the signal recording surface is transmitted again through the objective lens 1 and reflected by the reflecting mirror toward the light emitting / receiving module 27, and received by the light receiving element in the light receiving / emitting module 27 to read the signal. Operation is to be performed. In the figure, reference numeral 28 denotes a printed circuit board to which the light emitting / receiving module 27 is electrically connected. The printed circuit board 28 is fixed to the side surface of the optical chassis 25 by screwing or bonding.
[0029]
A square recess 25c is formed in the center of the optical chassis 25, and the base member (suspension base 7, yoke base 22) and the lens holder 2 supported by the base member are loaded in the recess 25c. Screw holes 25b, 25b are formed on the upper surface of the optical chassis 25 at positions facing the through holes 22g, 22g of the support pieces 22a, 22a of the yoke base 22, and the through holes 22g are formed from above the yoke base 22. , 22g inserted into the screw holes 25b, 25b, the front ends of the horizontal portions 22c, 22c, which are the free ends of the support pieces 22a, 22a, are on the axis O as described above. And is fixed to the optical chassis 25.
[0030]
As shown in FIG. 2, a through hole 25d is formed at a position facing the screw hole 22f of the yoke base 22 on the bottom surface of the optical chassis 25, and an adjustment screw 29 inserted through the through hole 25d. The tip of the screw is screwed into the screw hole 22f. A compression spring 30 is disposed between the adjustment piece 22 e in which the screw hole 22 f is formed and the inner bottom surface of the optical chassis 25 in a state where the compression spring 30 is externally attached to the adjustment screw 29. The compression spring 30 constantly urges the adjusting piece 22e of the yoke base 22 in a direction away from the inner bottom surface of the optical chassis 25, and thus the backlash of the fixing screw 29 and the yoke base 22 to the optical chassis 25 is prevented. It has become so. The adjustment piece 22 e and the screw hole 22 f of the yoke base 22, and the adjustment screw 29 and the compression spring 30 constitute an adjustment mechanism that varies the mounting angle of the yoke base 22 with respect to the optical chassis 25.
[0031]
When the adjusting screw 29 is rotated from the state shown in FIG. 2, the adjusting piece 22e of the yoke base 22 is finely moved in the focusing direction, and the yoke base 22 and the suspension base 7 mounted on the yoke base 22, the printed circuit board 4, Then, the lens holder 2 rotates around the hinge portions 22d and 22d of the support pieces 22a and 22a. Thereby, skew adjustment in the tangential direction (arrow t direction) of the optical axis L of the objective lens 1 is performed. The mounting angle of the yoke base 22 with respect to the optical chassis 25 after the skew adjustment is maintained by the urging force of the compression spring 30.
[0032]
As described above, since the hinge portions 22d and 22d of the support pieces 22a and 22a can be twisted and deformed around the axis O extending in the tracking direction through the center of the objective lens 1, the objective lens can be adjusted during skew adjustment in the tangential direction. The position in the focus direction of 1 does not change, so that the signal reading performance is not adversely affected. Note that if the position of the screw hole 7b in the focus direction is set so that the central axis of the fixing screw 21 serving as the rotation center of the printed circuit board 4 passes through the center of the objective lens 1, the objective can be adjusted even when adjusting the skew in the radial direction. Positional displacement of the lens 1 in the focus direction can be prevented.
[0033]
The support pieces 22a and 22a may be formed separately from the yoke base 22 and fixed to the yoke base 22. However, as in the embodiment described above, the support pieces 22a and 22a are bent integrally with the yoke base 22 by pressing. By forming, the number of parts is reduced, and the positional accuracy of the hinge portions 22d and 22d with respect to the center of the objective lens 1 is improved.
[0034]
Further, the free ends of the support pieces 22a and 22a are not necessarily fixed on the axis O. For example, the horizontal portions 22c and 22c are formed in an L shape in plan view, and the tips thereof are shown in FIG. May be fixed to the left side surface of the hinge portion 22d and 22d by fixing to the optical chassis 25 on the axis O passing through the centers of the hinge portions 22d and 22d, when a twisting stress is applied to the hinge portions 22d and 22d. The portion between the hinge portion 22d and the free end portion can be prevented from being undesirably curved and deformed, and thus the skew of the optical axis L of the objective lens 1 in the tangential direction without affecting the skew angle in the radial direction. Adjustment can be made reliably.
[0035]
In the above embodiment, the position where the screw hole 22f of the yoke base 22 is formed is set so that the rotation center of the adjustment screw 29 is located in a plane including the optical axis L of the objective lens 1 and perpendicular to the tracking direction. Therefore, since the twisting stress is equally applied to both the hinge portions 22d and 22d when the adjusting screw 29 is rotated, the skew adjustment in the tangential direction is performed reliably without affecting the skew angle in the radial direction. be able to.
[0036]
In the above embodiment, since the skew adjustment in the radial direction and the skew adjustment in the tangential direction are performed by separate rotation fulcrums (fixing screw 21 and hinge portions 22d and 22d), each skew adjustment operation is performed. Each can be performed independently, and the adjustment work can be automated.
[0037]
【The invention's effect】
As described above in detail, according to the optical pickup of the present invention, the base member is provided with the hinge part that can be twisted and deformed about the axis that extends in the tracking direction through the center of the objective lens, and the base member centered on the hinge part. By rotating the lens, the skew adjustment in the tangential direction of the optical axis of the objective lens can be performed, so that the conventional spherical annular protrusion and the spherical seat are unnecessary, and the skew adjustment mechanism is simplified. Manufacturing costs can be reduced.
[Brief description of the drawings]
FIG. 1 is a plan view of an optical pickup according to the present invention.
FIG. 2 is a side view showing the optical pickup of the present invention in a partial cross section.
3 is a cross-sectional view taken along the line AA in FIG.
FIG. 4 is a plan view of a conventional optical pickup.
FIG. 5 is a side view showing a conventional optical pickup in partial cross section.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Objective lens 2 Lens holder 3 Support member 4 Printed circuit board 7 Suspension base 21 Fixing screw 22 Yoke base 22a Support piece 22d Hinge part 22e Adjustment piece 22f Screw hole 23 Fixing screw 25 Optical chassis 27 Light emitting / receiving module 29 Adjustment screw 30 Compression spring L Optical axis O axis

Claims (3)

An objective lens for converging the light beam emitted from the light source on the signal recording surface of the disc, a lens holder for holding the objective lens, and the lens holder are supported via a support member so as to be movable in the focus direction and the tracking direction. An optical pickup having a base member and a chassis to which the base member is attached so as to be adjustable in angle.
Wherein the base member, the support pieces have a said center twist deformable hinge portion about an axis through extending in the tracking direction of the position and and the objective lens on both sides of the objective lens in the tracking direction is provided, this the support piece, the folded form of the metal plate with provided integrally with the base member, the free end side is fixed by a screw on the shaft against the chassis, between the base member and the chassis The optical pickup is provided with an adjustment mechanism for rotating the base member about the hinge portion to adjust the inclination of the optical axis of the objective lens in the tangential direction. The optical pickup according to claim 1, wherein the adjustment mechanism includes an adjustment screw whose rotation center is located in a plane that includes the optical axis of the objective lens and is orthogonal to the tracking direction. The support member has the free end side fixed to the lens holder and the base end side fixed to the substrate, respectively, and the base is centered on a rotation shaft portion extending in a direction perpendicular to both the focus direction and the tracking direction. The optical pickup according to claim 1, wherein the optical pickup is rotatably attached to the member.

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