JPH07262567A - Objective lens driving device - Google Patents

Abstract

PURPOSE:To obtain an objective lens driving device capable of improving workability to be adhered to a bobbin by adjusting the position of an objective lens. CONSTITUTION:The objective lens 3 of the objective lens driving device formed by packing an adhesive between the fitting part 4 of the bobbin 1 and the objective lens 3 is positioned in its optical axis direction by a projecting part 8 formed at the bobbin 1. A recessed part for widening the adhesive area is formed in the fitting part. A relief part for allowing the excessive adhesive to escape is formed at the bobbin 1 to prevent the adhesion of the adhesive to the lens face of the objective lens 3. Further, a clamp 9 holding the objective lens 3 at the time of assembly is positioned at an aperture 6 formed in a fitting part 4. The objective lens 3 is provided with an aperture of the same diameter as the aperture 5 of the bobbin 1 to easily align the centers of both. A hollow groove is formed on the outer periphery of the objective lens 3 to stabilize the supporting state by the clamp 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective lens driving device used for focusing an objective lens in an optical disc drive.

[0002]

2. Description of the Related Art Conventionally, as described in Japanese Patent Publication No. 4-62133, under the name "optical pickup",
Proposals have been made to adjust the optical axis of the objective lens. The contents are shown in FIG. A spherical surface 104 that contacts each other with a radius having the center of the radius as the center of the objective lens 101 is formed on a surface of the objective lens driving device 102 including the objective lens 101 facing the optical block 103. Then, the screw 1 inserted into the optical block 103
The objective lens driving device 102 and the optical block 103 are assembled by screwing 05a and 105b into the objective lens driving device 102. Also, the objective lens 1
01 optical axis 106 as a boundary
The left side of 2 is biased toward the optical block 103 side by a coil spring (not shown), and the objective lens driving device 1
The right side of 02 is biased in a direction away from the optical block 103. Then, by rotating the screw 105a, the objective lens driving device 102 is rotated to adjust the inclination of the optical axis 106 of the objective lens 101.

In the structure shown in FIG. 13, in order to adjust the inclination of the optical axis 106 without changing the position of the center of the objective lens 101, a spherical surface 104 is provided on the opposing surface of the objective lens driving device 102 and the optical block 103. Must be formed. In order to form this spherical surface 104, a dimensional allowance is required in the height direction, and further, in order to deflect the optical path, a deflecting means such as a prism 107 must be arranged below the curved surface 104. The size increases.

In view of the above, there is also one in which the tilt of the objective lens is adjusted only on the side of the objective lens driving device. That is, although not shown, the objective lens is loosely fitted in a bobbin driven in the optical axis direction of the objective lens with a predetermined gap, and after adjusting the optical axis of the objective lens, the objective lens and the bobbin are placed in the gap. There is a method of filling with an adhesive.

[0005]

When an adhesive is filled in the gap between the bobbin and the objective lens, it is difficult to position the objective lens in the optical axis direction and the direction orthogonal to the optical axis direction. Further, there is a problem that the adhesive strength is insufficient and the adhesive may stick out to the lens surface of the objective lens, which makes the bonding work difficult.

[0006]

The invention according to claim 1 is
A bobbin which has a fitting portion for loosely fitting an objective lens facing the recording medium and is driven in the optical axis direction of the objective lens is provided, and the bobbin is provided between the outer periphery of the objective lens and the fitting portion. In an objective lens driving device filled with an adhesive, a reference surface is formed near the outer periphery of one surface of the objective lens, and a convex portion supporting the reference surface is integrally formed on the bobbin.

A second aspect of the present invention is the objective lens driving device according to the first aspect of the present invention, wherein a plurality of recesses are formed on the inner peripheral surface of the fitting portion for filling with an adhesive.

According to a third aspect of the present invention, in the first aspect of the invention, the adhesive which is in communication with the gap between the fitting portion and the objective lens and is filled in the gap is applied in the outer peripheral direction of the objective lens. This is an objective lens driving device in which a relief portion that escapes to a bobbin is formed.

A fourth aspect of the present invention is the objective lens driving device according to the first aspect of the invention, wherein openings are formed at least at two locations on the outer periphery of the fitting portion.

According to a fifth aspect of the present invention, there is provided a bobbin which has a fitting portion for loosely fitting the objective lens facing the recording medium and is driven in the optical axis direction of the objective lens. In an objective lens driving device in which an adhesive is filled between the outer periphery of the objective lens and the fitting portion, an objective having an aperture of the same diameter provided on the surface of the objective lens opposite to the recording medium and the bobbin. It is a lens driving device.

According to a sixth aspect of the present invention, there is provided a bobbin which has a fitting portion for loosely and freely fitting an objective lens facing a recording medium and is driven in the optical axis direction of the objective lens. An objective lens driving device in which an adhesive is filled between the outer periphery of the objective lens and the fitting portion, wherein the outer peripheral surface of the objective lens is formed with a groove along the circumferential direction thereof.

[0012]

According to the first aspect of the invention, since the adhesive can be hardened while the reference surface of the objective lens is supported by the convex portion, the objective lens can be positioned in the optical axis direction. Become. Further, by setting the position of the convex portion in the tangential direction, it is possible to prevent the bobbin from tilting in the tracking direction when the objective lens contacts the convex portion.

According to the second aspect of the present invention, the adhesive area of the adhesive can be expanded by the recess formed on the inner peripheral surface of the fitting portion, whereby the adhesive strength can be increased. Further, since the objective lens is servoed at a certain frequency but firmly adhered to the bobbin, it is possible to move the objective lens and the bobbin as a unit, thereby improving frequency characteristics.

According to the third aspect of the present invention, when the amount of the adhesive filled in the gap between the fitting portion and the objective lens is too large, the excess amount of the adhesive is allowed to escape to the escape portion. Therefore, it becomes possible to prevent the adhesive from adhering to the lens surface of the objective lens.

According to the fourth aspect of the present invention, the clamp for holding the objective lens is positioned at the opening of the fitting portion, so that the insertion and the bonding work of the objective lens to the fitting portion can be performed in a stable state. Is possible.

According to the fifth aspect of the invention, the light amount of the light flux passing through the objective lens is made incident on the light receiving element, and the objective lens is arranged in the direction orthogonal to the optical axis thereof so that the light receiving amount of the light receiving element is maximized. By displacing, when the center of the objective lens is determined at the center of the fitting portion of the bobbin, it is possible to facilitate the alignment because the objective lens and the bobbin have the apertures of the same diameter. This makes it possible to make the gap between the fitting portion and the objective lens and the filling amount of the adhesive uniform over the entire circumference.

According to the sixth aspect of the present invention, when the objective lens is aligned and inserted into the fitting portion of the bobbin, the tip of the clamp is engaged with the concave groove formed on the outer peripheral surface of the objective lens. , Stabilize the holding state of the objective lens by the clamp, facilitate the optical axis adjustment of the objective lens, and
By forming the concave groove, it is possible to increase the adhesive area and increase the adhesive strength.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the invention described in claims 1 and 4 is shown in FIG.
Or, it demonstrates based on FIG. First, referring to FIG.
Indicates. An objective lens 3 (see FIG.
(See FIG. 3) is a fitting portion 4 for loosely fitting a predetermined gap.
And the aperture 5 is formed. Further, openings 6 are formed at two places of the fitting portion 4. Furthermore, bobbin 1
A flat convex portion 8 that supports the outer peripheral portion of the reference surface 7 of the objective lens 3 is formed on the upper surface 2 in a protruding state. This convex portion 8
The direction in which is formed is the tracking direction X in FIG.
It is a tangential direction Y orthogonal to.

Then, the outer circumference of the objective lens 3 is held by the clamp 9 from opposite directions. In this state, the tilt of the optical axis of the objective lens 3 and the position of the center of the objective lens 3 with respect to the center of the fitting portion 4 are adjusted, and the objective lens 3 is moved while the clamp 9 is positioned in the opening 6 of the bobbin 1. Mating part 4
2 and the ultraviolet curable adhesive 10 is filled in the gap between the outer circumference of the objective lens 3 and the fitting portion 4 as shown in FIG. The objective lens 3 is adhered. At the time of bonding, the adhesive 10 may be applied in advance to at least one of the inner surface of the fitting portion 4 and the outer peripheral surface of the objective lens 3.

In such a configuration, the adhesive 10 can be cured while the reference surface 7 of the objective lens 3 is supported by the convex portion 8, so that the objective lens 3 can be positioned in the optical axis direction. Becomes Further, by determining the position of the convex portion 8 in the tangential direction Y, the objective lens 3
It is possible to prevent the bobbin 1 from tilting in the tracking direction X when the abutment contacts the convex portion 8. This is the effect of the invention according to claim 1. When the bobbin 1 is slidably held by a guide member such as a shaft, the bobbin 1 is prevented from tilting. Therefore, even if the convex portion 8 is positioned at an arbitrary position and abuts on the reference surface 7. Good.

A clamp 9 for holding the objective lens 3
By locating at the opening portion 6 of the fitting portion 4, it becomes possible to insert and bond the objective lens 3 to the fitting portion 4 in a stable state. In this case, as shown in FIG. 5, the openings 6 are formed at three positions of the fitting portion 4, and the openings 6 are formed.
The same effect can be obtained even if the objective lens 3 is held from three directions by the clamp positioned at. This is claim 4
This is the effect of the described invention. As shown in FIG. 6, even when the objective lens 3 is held by the two clamps 9, a contact piece 9a having a small contact area with the objective lens 3 is attached to the tip of one clamp 9 and the other clamp 9 is attached. By forming one at the tip, the outer circumference of the objective lens 3 can be held in a stable state from three directions.

Further, as shown in FIG. 7, the objective lens 3
By forming an annular groove 3 along the circumferential direction on the outer peripheral surface of the, and engaging the tip of the clamp 9 with the groove 3a, the movement of the objective lens 3 with respect to the clamp 9 in the direction A in which the optical axis 11 falls. The optical axis 11 of the objective lens 3 can be adjusted correctly. Furthermore, by forming the groove 3a, it is possible to increase the adhesive area and increase the adhesive strength. This is an effect corresponding to the invention of claim 6. In this case, depending on the cross-sectional shape of the concave groove 3a, as shown in FIG. 7, it is possible to further stabilize the holding property of the objective lens 3 by using a clamp 9 having a tapered tip.

Next, an embodiment of the invention described in claim 2 will be described with reference to FIG. The same parts as those in the above-described embodiment are designated by the same reference numerals and the description thereof is omitted (the same applies hereinafter). In the present invention, a plurality of recesses 12 are formed on the inner peripheral surface of the fitting portion 4.
Therefore, it becomes possible to increase the adhesive area by increasing the adhesive area of the adhesive 10 by the recess 12. This allows
It is possible to prevent the displacement of the objective lens 3 due to a change with time. In addition, the coil of bobbin 1 (not shown)
When a wave is input, the bobbin 1, the coil, and the objective lens 3 vibrate, but since the objective lens 3 and the bobbin 1 are firmly adhered, the objective lens 3 and the bobbin 1 can be moved integrally. . As a result, frequency characteristics can be improved.

Further, an embodiment of the invention described in claim 3 will be described with reference to FIG. The present invention communicates with the gap between the fitting portion 4 and the objective lens 3 and allows the adhesive 10 filled in the gap to escape toward the outer peripheral direction of the objective lens 3.
Is formed on the bobbin 1. The figure (a) is the example which formed the relief part 13 which penetrates below, and the figure (b) formed the relief part 13 with a bottom. Therefore, when the amount of the adhesive 10 filled in the gap between the fitting portion 4 and the objective lens 3 is too large, the excess amount of the adhesive 10 can be released to the escape portion 13. This makes it possible to prevent the adhesive from adhering to the lens surface of the objective lens 3. Therefore,
It is possible to prevent the deterioration of the optical signal passing through the objective lens.

Further, an embodiment of the invention described in claim 5 will be described with reference to FIGS. As shown in FIG. 10, the present invention is a recording medium (not shown) for the objective lens 3.
An aperture 14 having the same diameter as the aperture 5 of the bobbin 1 is provided on the surface opposite to the side. Therefore, FIG.
As shown in, the light flux that has passed through the objective lens 3 from below the bobbin 1 is incident on the light receiving element 15, and the objective lens 3 is displaced in the direction orthogonal to the optical axis so that the light receiving amount of the light receiving element 15 is maximized. By doing so, when the center of the objective lens 3 is determined at the center of the fitting portion 4 of the bobbin 1, the bobbin 1 and the objective lens 3 are provided with the apertures 5 and 14 of the same diameter, so that the alignment can be easily performed. It becomes possible to do. Thereby, as shown in FIG. 10, the gap Δs between the fitting portion 4 and the objective lens 3 and the filling amount of the adhesive 10 can be made uniform over the entire circumference.

The adhesive 10 may expand or contract depending on the ambient temperature, but since the filling amount of the adhesive 10 is uniform over the entire circumference, the objective lens 3 is expanded even if the adhesive 10 expands or contracts. The position shift of the center of the can be suppressed. Although the aperture 14 is formed by painting the objective lens 3, as shown in FIG. 12A, it is formed by fixing a light-shielding cover 16 made of plastic or the like, or made of plastic. When the objective lens 3 of No. 2 is used, as shown in FIG. 12B, two-color molding is performed using a transparent resin and a light-shielding resin, and the aperture 14 is formed by the light-shielding portion 17 as well. The effect can be obtained.

[0027]

According to the first aspect of the present invention, the reference surface is formed in the vicinity of the outer periphery of one surface of the objective lens, and the convex portion supporting the reference surface is integrally formed on the bobbin. The adhesive can be cured while being supported by the
This makes it possible to position the objective lens in the optical axis direction, and by determining the position of the convex portion in the tangential direction, it is possible to prevent the bobbin from tilting in the tracking direction when the objective lens contacts the convex portion. Can be prevented.

According to a second aspect of the present invention, in the first aspect of the present invention, since a plurality of recesses for filling the adhesive are formed on the inner peripheral surface of the fitting portion, these recesses increase the adhesive bonding area of the adhesive. The objective lens and the bobbin can be moved integrally because the objective lens is servoed at a certain frequency but firmly adhered to the bobbin. As a result, the frequency characteristic is improved.

According to a third aspect of the present invention, in the first aspect of the present invention, since the escape portion communicating with the gap between the fitting portion and the objective lens is formed on the bobbin, the fitting portion and the objective lens are not separated from each other. If there is too much adhesive filling the gap between them, it is possible to prevent the adhesive from adhering to the lens surface of the objective lens, as the excess adhesive can escape to the escape area. Therefore, it is possible to prevent the deterioration of the optical signal passing through the objective lens.

According to a fourth aspect of the invention, in the invention of the first aspect, since the openings are formed at least at two locations on the outer periphery of the fitting portion, a clamp for holding the objective lens is provided in the opening of the fitting portion. By positioning it, it is possible to stably insert and bond the objective lens to the fitting portion.

According to the fifth aspect of the present invention, since the aperture of the same diameter is provided on the surface of the objective lens on the side opposite to the recording medium and on the bobbin, the light quantity of the light flux passing through the objective lens enters the light receiving element, By displacing the objective lens in the direction orthogonal to its optical axis so that the amount of light received by the light receiving element becomes maximum,
When the center of the objective lens is determined at the center of the fitting portion of the bobbin, the objective lens and the bobbin are provided with apertures of the same diameter, which facilitates the alignment. The gap between the objective lens and the filling amount of the adhesive can be made uniform over the entire circumference, and therefore, even if the adhesive expands or contracts, the displacement of the center of the objective lens can be suppressed.

According to the sixth aspect of the present invention, since the concave groove is formed on the outer peripheral surface of the objective lens along the circumferential direction thereof, when the objective lens is aligned and inserted into the fitting portion of the bobbin, the objective lens of the objective lens is inserted. By engaging the tip of the clamp with the concave groove formed on the outer peripheral surface, the holding state of the objective lens by the clamp is stabilized, the optical axis of the objective lens is easily adjusted, and the adhesive area is formed by forming the concave groove. It can be spread to increase the adhesive strength.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an assembly structure of an objective lens driving device in an embodiment of the invention described in claims 1 and 4. FIG.

FIG. 2 is a vertical cross-sectional front view of an objective lens driving device in a section along the tracking direction.

FIG. 3 is a vertical cross-sectional front view of the objective lens driving device in a section along the tangential direction.

FIG. 4 is a perspective view of a bobbin.

FIG. 5 is a partial perspective view showing another example of the opening formed on the bobbin.

FIG. 6 is a perspective view showing another example in which an objective lens is held by a clamp.

FIG. 7 is a side view showing a support state of an objective lens by a clamp in an embodiment of the invention as set forth in claim 6;

FIG. 8 is a perspective view of a part of the bobbin according to the second embodiment of the invention.

FIG. 9 is a vertical sectional front view of an objective lens driving device according to an embodiment of the present invention.

FIG. 10 is a vertical sectional front view of an objective lens driving device according to an embodiment of the present invention.

FIG. 11 is a vertical cross-sectional front view showing how the position of the objective lens is adjusted.

FIG. 12 is a cross-sectional view showing a modified example of the aperture.

FIG. 13 is a front view showing a conventional example.

[Explanation of symbols]

 1 bobbin 3 objective lens 3a concave groove 4 fitting part 5 aperture 6 opening 7 reference surface 8 convex part 10 adhesive 12 concave part 13 escape part 14 aperture

Claims (6)

[Claims] 1. A bobbin having a fitting portion for loosely fitting an objective lens facing a recording medium in an adjustable manner, the bobbin being driven in the optical axis direction of the objective lens, and the fitting with the outer periphery of the objective lens. In the objective lens driving device in which an adhesive is filled between the base and the base, a reference surface is formed in the vicinity of the outer periphery of one surface of the objective lens, and a convex portion supporting the reference surface is integrally formed on the bobbin. Characteristic objective lens drive device. 2. The objective lens driving device according to claim 1, wherein a plurality of recesses for filling the adhesive are formed on the inner peripheral surface of the fitting portion. 3. A bobbin is formed with an escape portion that communicates with a gap between the fitting portion and the objective lens and allows the adhesive filled in the gap to escape in the outer peripheral direction of the objective lens. The objective lens driving device according to claim 1. 4. The objective lens driving device according to claim 1, wherein openings are formed at least at two locations on the outer periphery of the fitting portion. 5. A bobbin which has a fitting portion for loosely fitting an objective lens facing a recording medium and is driven in the optical axis direction of the objective lens is provided, and the outer periphery of the objective lens is fitted with the bobbin. In an objective lens driving device in which an adhesive is filled between the objective lens and the portion, an aperture having the same diameter is provided on the surface of the objective lens opposite to the recording medium and the bobbin. Drive. 6. A bobbin that has a fitting portion for loosely fitting an objective lens facing a recording medium and is driven in the optical axis direction of the objective lens is provided, and the outer periphery of the objective lens is fitted with the bobbin. An objective lens driving device in which an adhesive is filled between the objective lens driving device and the outer surface of the objective lens, wherein a concave groove is formed along the circumferential direction of the objective lens driving device.