JP2010129114A - Lens holding member and lens driver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens holder which adjusts an optical axial direction of an objective lens, that is, adjusts an arrangement angle of the objective lens in a state wherein the objective lens is stably supported. <P>SOLUTION: In the lens holder 20 including the objective lens 10a and at least three supporting surfaces 11 holding the objective lens 10a and coming in contact with the objective lens 10a to support the objective lens 10a, each of the lens supporting surfaces 11 has a flat or convex surface, is disposed along one circumference of a circle having a center axis of the objective lens 10a as the center thereof and faces the center axis of the objective lens 10a. Thereby, the optical axial direction of the objective lens 10a is adjusted in a state wherein the objective lens 10a is stably supported by the lens holder 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an objective lens holding member of an optical pickup device used when recording information on an optical recording medium such as an optical disk or reproducing information from the optical recording medium, and more specifically, stabilizes the objective lens. In particular, the present invention relates to an objective lens holding member, an objective lens driving device, and an optical pickup device that can perform tilt adjustment while being held.

  Conventionally, an optical pickup device that records information on an optical recording medium such as an optical disk or reproduces information from the optical recording medium has been provided with an objective lens that focuses a light beam on the optical recording medium. This objective lens is fixed to the lens holding portion of the objective lens driving device in a state where the direction of the optical axis of the objective lens is adjusted.

  FIG. 6 is a plan view showing a configuration of a conventional lens holder (lens holding member). The lens holder 100 includes three lens support surfaces 111 formed side by side on the circumference, and three lens adhesion portions 112 formed next to the lens support surface 111, respectively. The objective lens 110 is disposed at the center of the three lens support surfaces 111 of the lens holder 100 and is supported by each lens support surface 111. The objective lens 110 is fixed to the lens holder 100 with an adhesive injected into the lens bonding portion 112.

  FIG. 7 is a cross-sectional view showing a BB cross section of FIG. 6. An optical path 113 that allows the light beam to pass therethrough is provided around the optical axis L2 below the objective lens 110 in the lens holder 100. The outer periphery of the objective lens 110 is supported in contact with the lens support surface 111. The objective lens 110 is fixed to the lens holder 100 with an adhesive (not shown) injected into the lens bonding portion 112.

  Here, the three lens support surfaces 111 are substantially spherical surfaces, and when the circular objective lens 110 is installed on the lens support surface 111, the center of the substantially spherical surface is configured to substantially coincide with the optical axis L2. In the configuration in which the lens support surface 111 is spherical, the design is easy because the concave spherical surface of the lens support surface 111 may be designed around a point on the optical axis L2 of the objective lens 110. Such a lens holder is described in Patent Document 1, for example.

Since the lens support surface is formed in a spherical shape, the angle at which the objective lens is arranged can be adjusted, and the direction of the optical axis of the objective lens can be adjusted.
JP 2006-209875 A (published August 10, 2006)

  However, the conventional configuration has a problem that it is difficult to adjust the arrangement angle of the objective lens when the objective lens is installed.

  The portion where the objective lens 110, which is circular when viewed from the direction of the optical axis L2, and the lens support surface 111, which is spherical, are in contact with each other, becomes a circular arc when viewed in FIG. That is, the objective lens 110 and the lens support surface 111 are in contact with each other with a line. Therefore, when the objective lens 110 or the lens support surface 111 is distorted due to a manufacturing error and the optical axis L2 of the objective lens 110 and the center of the spherical surface of the lens support surface 111 are shifted, the objective lens 110 and the lens support surface 111 are Then, by changing the arrangement angle of the objective lens 110, the contact is made with a line, or the contact is made with a plurality or one point. For example, when the objective lens 110 and one lens support surface 111 are in contact only at two points of the first and second points, if the arrangement angle of the objective lens 110 is changed, one of the points is separated and the objective The lens 110 and one lens support surface 111 may come into contact only at one point. As described above, when the contact line or the contact point changes discontinuously by changing the arrangement angle of the objective lens 110, the support position of the objective lens 110 may become unstable, and the arrangement angle of the objective lens 110 is continuously changed. It becomes difficult to change. That is, it becomes difficult to adjust the direction of the optical axis L2 of the objective lens 110.

  The present invention has been made in view of the above problems, and its purpose is to adjust the direction of the optical axis of the objective lens in a state where the objective lens is stably supported, that is, to change the angle of arrangement of the objective lens. It is to realize a lens holder that can be adjusted.

  In order to solve the above problems, a lens holding member according to the present invention includes a lens and is a lens holding member that holds the lens, and has at least three support surfaces that support the lens in contact with the lens. The support surface is a flat surface or a convex surface, is arranged along one circumference centered on the central axis of the lens, and faces the central axis of the lens. .

  In the above configuration, when the number of supporting surfaces for one lens is three, the supporting surface is a plane or a convex surface, and thus the lens is supported at three points by the supporting surface. Therefore, when the arrangement angle of the lens is changed, the lens and each support surface are always in contact with each other only at one point, and the contact points continuously move on the support surface. Therefore, the direction of the optical axis can be adjusted by continuously and smoothly changing the lens arrangement angle while the lens is stably supported on the lens holding member.

  Further, four or more support surfaces may be provided for one lens.

  According to said structure, the location which supports a lens increases, and the support location of a lens can be arrange | positioned more equally. Therefore, since the stress applied to the lens at the time of bonding can be more evenly distributed, the deformation of the lens becomes isotropic with respect to the central axis of the lens. Therefore, since distortion of the lens after bonding can be reduced, it is easy to adjust the direction of the optical axis before bonding.

  A plurality of concave adhesive portions for storing an adhesive for adhering the lens may be provided, and each adhesive portion may be disposed adjacent to the outside of the support surface with respect to the central axis of the lens.

  According to said structure, the stress which arises in a lens resulting from adhesion | attachment of the lens in an adhesion part can be disperse | distributed to a lens holding member via the support surface adjacent to an adhesion part. Therefore, since distortion of the lens after bonding can be reduced, it is easy to adjust the direction of the optical axis before bonding.

  A part of the adhesive portion may be a conical recess.

  According to said structure, when apply | coating or inject | pouring an adhesive agent into an adhesion part, an adhesive agent does not spread outside a recessed part, but it is easy to remain in the range enclosed by a recessed part and a lens. Therefore, the adhesion state between the lens and the lens holding member can be stabilized.

  The lens may have a corner that contacts the support surface along a circumference centered on the central axis of the lens.

  The lens driving device according to the present invention includes a movable portion and a support portion that supports the movable portion so as to be displaceable, and the movable portion includes the lens holding member.

  According to said structure, the lens which can adjust the direction of an optical axis by changing the arrangement | positioning angle of a lens continuously and smoothly in the state where the lens was stably supported on the lens holding member. A driving device can be realized.

  The lens holding member according to the present invention includes a lens and is a lens holding member that holds the lens, and has at least three support surfaces that contact the lens and support the lens, and the support surface is a flat surface. Or it is a convex surface, it is arrange | positioned along one circumference centering on the central axis of the said lens, and it is characterized by facing the central axis of the said lens.

  Therefore, the direction of the optical axis can be adjusted by continuously and smoothly changing the lens arrangement angle while the lens is stably supported on the lens holding member.

[Embodiment 1]
Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing the configuration of the objective lens driving device of the present embodiment. The objective lens driving device (lens driving device) 30 includes a movable portion 1 and a support portion 2 that supports the movable portion 1. The support unit 2 includes a base member 3, an elastic support member 4 that couples the movable unit 1 to the base member 3 and supports the movable unit 1 on the support unit 2, a magnet 5 that is a magnetic field generating unit, and an external control device ( And a flexible substrate 6 for connection to a device (not shown). The objective lens driving device 30 is mounted on an optical pickup device that records information on an optical disc or reproduces information from the optical disc.

  Hereinafter, the radial direction of the optical disk (optical recording member; not shown) is referred to as the radial direction, the tangential direction of the track of the optical disk is referred to as the tangential direction, and the optical axis direction of the objective lens (lens) 10 is referred to as the focus direction. The recording plane of the optical disk is located on one side of the objective lens 10 in the optical axis direction.

  The elastic support member 4 is elastically deformable, and the elastic support member 4 supports the movable part 1 so that the movable part 1 can move in the radial direction and the focus direction with respect to the support part 2.

  The movable part 1 includes two objective lenses 10a and 10b for condensing a light beam on an optical disc, a lens holder (lens holding member) 20 for fixing the objective lenses 10a and 10b, and the movable part 1 by electromagnetic force. A radial coil 7 for displacing in the radial direction and a focus coil 8 for displacing the movable part 1 in the focus direction by electromagnetic force are provided.

  The two objective lenses 10a and 10b are arranged side by side in the tangential direction. The objective lenses 10a and 10b collect light beams having different wavelengths on the optical disc according to the type of the optical disc such as a CD or a DVD.

  The focus coils 8 are symmetrically arranged on a plane that includes the centers of the objective lenses 10a and 10b and is perpendicular to the radial direction. The focus coil 8 is a coil wound around the focus direction.

  The radial coil 7 is disposed on the surface of the lens holder 20 facing the magnet 5 and is symmetrically disposed in a plane that includes the centers of the objective lenses 10a and 10b and is perpendicular to the radial direction. The radial coil 7 is a coil wound around the tangential direction. Since only a part of the radial coil 7 is used as an effective magnetic field, the radial coil 7 protrudes so as to face the magnet 5.

  FIG. 2 is a plan view showing the configuration of the lens holder of the present embodiment. In the lens holder 20, two objective lenses 10a and 10b are arranged. The lens holder 20 has three lens adhesion portions (adhesion portions) 12 on the outer peripheral portion of each of the arranged objective lenses 10a and 10b. The objective lenses 10 a and 10 b are fixed to the lens holder 20 by an adhesive injected into the lens bonding portion 12. The lens holder 20 includes three lens support surfaces (support surfaces) 11 that support the objective lenses 10a and 10b in the same radial direction as the lens bonding portion 12 with the central axes of the objective lenses 10a and 10b as the center. Has been. Each lens support surface 11 is arranged on the circumference centering on the central axis (optical axis) of the objective lens. The lens support surface 11 is arranged so that the triangle formed by connecting the contact points between the lens support surfaces 11 and the objective lens 10a (or the objective lens 10b) becomes an acute triangle. Therefore, the objective lenses 10a and 10b can be stably supported by the three lens support surfaces 11 one by one. Since the objective lens 10a and the objective lens 10b are supported by the same configuration, only the configuration for supporting the objective lens 10a will be described below.

  FIG. 3 is an enlarged perspective view showing the configuration of the lens support surface and the lens bonding portion. In this figure, the objective lens is not shown. The lens support surface 11 has a planar shape, and the surface thereof faces the central axis (optical axis) of the objective lens. That is, one of the normal lines drawn from the surface of the lens support surface 11 intersects the central axis of the objective lens. The lens bonding portion 12 is a concave portion having a conical side surface. Therefore, when the objective lens is arranged and the adhesive is applied or injected, the adhesive does not spread outside the recess and remains in the range surrounded by the recess and the objective lens. Can be stabilized. Further, by forming the lens bonding portion 12 in a conical shape, the application shape of the adhesive is more stable than in the case where the lens bonding portion has a groove shape as in Patent Document 1, for example, and stable bonding is possible.

  FIG. 4 is a cross-sectional view showing the AA cross section of FIG. The shape of the objective lens 10a is symmetric about the optical axis L1. An optical path 13 through which the light beam passes is provided around the optical axis L1 below the objective lens 10a in the lens holder 20. The objective lens 10a is supported such that a corner portion outside the lens portion is in contact with the lens support surface 11. The corner portion that is a contact portion with the lens support surface 11 is formed along a circumference centered on the optical axis L1 of the objective lens 10a. The objective lens 10 a is fixed to the lens holder 20 with an adhesive injected into the lens bonding portion 12.

  Here, each lens support surface 11 is a flat surface, and when the circular objective lens 10a is installed in the lens holder 20, the outer periphery of the objective lens 10a and each lens support surface 11 are in contact with each other at one point. That is, the objective lens 10 a is supported at three points by the three lens support surfaces 11 of the lens holder 20. Therefore, the objective lens 10a and each lens support surface 11 are always in contact with only one point even when the arrangement angle of the objective lens 10a is changed. Therefore, the objective lens 10 a is stably supported on the lens holder 20. Further, the contact point between the objective lens 10a and each lens support surface 11 continuously moves on the lens support surface 11 by changing the arrangement angle of the objective lens 10a. Therefore, it is possible to continuously change the arrangement angle of the objective lens 10a in a state where the objective lens 10a is stably supported on the lens holder 20. That is, it is easy to adjust the direction of the optical axis L1 of the objective lens 10a.

  One lens bonding portion 12 is provided for each lens support surface 11. When the objective lens 10a is bonded to the lens holder 20, the adhesive condenses due to the curing of the adhesive, thereby causing stress on the objective lens 10a. The objective lens 10a may be deformed by this stress. Here, the lens bonding portion 12 is disposed adjacent to the outside of the lens support surface 11 with respect to the central axis of the objective lens 10a. Therefore, the stress generated in the objective lens 10 a due to the adhesion at the lens adhesion part 12 can be dispersed in the lens holder 20 via the lens support surface 11 adjacent to the lens adhesion part 12. Therefore, deformation of the objective lens 10a due to bonding can be reduced, and the direction of the optical axis of the objective lens 10a can be prevented from being shifted after bonding.

[Embodiment 2]
FIG. 5 is a plan view showing the configuration of the lens holder of the present embodiment. In the present embodiment, members having the same functions or configurations as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In the first embodiment, three lens support surfaces are provided for each objective lens. However, the lens holder 21 of the present embodiment has a configuration in which four lens support surfaces 11 are provided for one objective lens 10a. belongs to.

  Each lens support surface 11 is arranged so that the outer periphery of the objective lens 10a is divided into four equal parts. One lens bonding portion 12 is provided for each lens support surface 11. As in the first embodiment, each lens support surface 11 is a flat surface, and when the circular objective lens 10a is installed in the lens holder 21, the outer periphery of the objective lens 10a and each lens support surface 11 are in one point. Touch. Therefore, the direction of the optical axis of the objective lens 10a can be adjusted while the objective lens 10a is stably supported on the lens holder 20. That is, the arrangement angle of the objective lens can be changed more smoothly (continuously) than when the lens support surface is formed of a concave surface such as a spherical surface.

  Moreover, the lens adhesion part 12 is arrange | positioned at four places with respect to one objective lens 10a. Compared to the first embodiment, since the adhesion portion and the support portion of the objective lens 10a are arranged more evenly on the outer periphery of the objective lens 10a, the deformation of the objective lens 10a is more isotropic with respect to the center of the objective lens 10a. Thus, the distortion of the objective lens 10a can be reduced. Therefore, it is possible to prevent the direction of the optical axis of the objective lens 10a from deviating after bonding.

  In the above embodiment, the number of lens support surfaces provided in the lens holder is three or four for one objective lens, but may be larger than that. As the number of lens support surfaces increases, the stress inside the objective lens becomes more isotropic and the distortion of the objective lens is reduced. On the other hand, when the number of lens support surfaces is small, the arrangement angle of the objective lens can be changed more smoothly.

  Further, although the lens support surface is a flat surface, it may be a convex surface. Also in this case, each lens support surface is in contact with the objective lens at one point.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The present invention can be applied to a holding mechanism that needs to adjust the arrangement angle of a condensing member such as a lens.

1 is a perspective view illustrating a configuration of an objective lens driving device according to Embodiment 1. FIG. 3 is a plan view showing a configuration of a lens holder according to Embodiment 1. FIG. It is an expansion perspective view which shows the structure of the lens support surface of FIG. 2, and a lens adhesion part. It is sectional drawing which shows the AA cross section of FIG. 6 is a plan view showing a configuration of a lens holder according to Embodiment 2. FIG. It is a top view which shows the structure of the conventional lens holder. It is sectional drawing which shows the BB cross section of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Movable part 2 Support part 3 Base member 4 Elastic support member 5 Magnet 6 Flexible board 7 Radial coil 8 Focus coil 10, 10a, 10b Objective lens (lens)
11 Lens support surface (support surface)
12 Lens bonding part (bonding part)
20, 21 Lens holder (Lens holding member)
30 Objective lens drive (lens drive)

Claims (7)

In a lens holding member that includes a lens and holds the lens,
Having at least three support surfaces in contact with the lens and supporting the lens;
The support surface is a flat surface or a convex surface, is disposed along one circumference centered on the central axis of the lens, and faces the central axis of the lens. Element.   The lens holding member according to claim 1, wherein the number of the support surfaces for one lens is three.   The lens holding member according to claim 1, wherein four or more support surfaces are provided for one lens.   A plurality of concave adhesive portions for accumulating an adhesive for adhering the lens are provided, and each adhesive portion is disposed adjacent to the outside of the support surface with respect to the central axis of the lens. Item 4. The lens holding member according to any one of Items 1 to 3.   The lens holding member according to claim 4, wherein a part of the adhesive portion is a conical concave portion.   6. The lens holding member according to claim 1, wherein the lens has a corner that contacts the support surface along a circumference centered on a central axis of the lens. . A movable part, and a support part that supports the movable part to be displaceable,
The lens driving device according to claim 1, wherein the movable portion includes the lens holding member according to claim 1.

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