JP2004139694A - Objective lens holding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an objective lens holding device which can be miniaturized sufficiently and which is easy to fix by adhesion. <P>SOLUTION: Protectors 41, 42 are fixed at both sides of a lens holder 33 mounting an objective lens 32. The protectors 41, 42 are made of raw material softer than an object substance such as an optical disk, the objective lens 32 and the lens holder. A dam is formed for adhesive by the protectors 41, 42 and the lens holder, the applied adhesive can be made not to flow out until hardening so as to form an adhesive layer 43. The adhesive layer 43 fixes simultaneously the objective lens 32 and the protectors 41, 42 to the lens holder 33. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an objective lens holding device that holds an objective lens with an optical pickup or the like.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an optical pickup device having an objective lens has been used for a recording medium such as a CD (Compact Disc) and a DVD (Digital Versatile Disc) that optically records and reproduces information. In the optical pickup device, dynamic servo control is performed so that the objective lens is brought close to the recording medium and the position is appropriate. In the direction of servo control, a focus servo that changes the distance between the objective lens and the recording medium on the optical axis of the objective lens, and a direction perpendicular to the optical axis so as to follow a track on which information is recorded on the recording medium. Tracking servo for changing the position in the direction is performed.
[0003]
FIG. 9 shows a schematic configuration of an objective lens holding device 1 conventionally used as a component for holding an objective lens in an optical pickup device. The objective lens holding device 1 includes an objective lens 2 which is basically a convex lens, and a lens holder 3 holding the objective lens 2. The lens holder 3 is wound with tracking coils 4 and 5 for generating an electromagnetic force for tracking servo and focus coils 6 and 7 for generating an electromagnetic force for focus servo. The lens holder 3 is also provided with terminals 8, 9, and 10 for energizing these coils.
[0004]
The optical pickup device has a structure in which the objective lens 2 can be moved in the optical axis direction with the optical axis perpendicular to the surface of the recording medium in order to apply focus servo. The moving range is restricted to a certain range by a stopper or the like, so that the objective lens 2 or the lens holder 3 does not contact the recording medium. However, as the size of the optical pickup device is reduced, the distance between the surface of the recording medium and the objective lens 2 is reduced, and the objective lens 2 or a part of the lens holder 3 comes into contact with the surface of the recording medium. Is coming. In this case, if contact occurs, the objective lens 2 or the recording medium may be damaged, causing an effect of deteriorating the information reading and writing performance, which is a problem.
[0005]
Therefore, what is considered is to use the protectors 11 and 12. The protectors 11 and 12 are made of a material softer than the recording medium. The protectors 11 and 12 contact the recording medium first so that the objective lens 2 or the lens holder 3 does not contact the recording medium. The lens 2 is prevented from being damaged. An adhesive is used to fix the objective lens 2 and the protectors 11 and 12 to the lens holder 3.
[0006]
FIG. 10 shows a simplified state of reading and writing information using the objective lens holding device 1 of FIG. An optical disk 15 such as a CD or a DVD is used as a recording medium. A laser beam is launched from an optical module 16 and guided to the objective lens 2 using an optical component such as a mirror 17, and is irradiated on an information recording portion of the optical disk 15. When reading information, the reflected light from the information recording portion is collected by the objective lens 2 and received by the optical module 16 to read the information. If the tips of the protectors 11 and 12 are set closer to the optical disc 15 than the objective lens 2 and the lens holder 3, the tips of the protectors 11 and 12 will be close even if the objective lens holding device 1 approaches the surface of the optical disc 15. Contact first.
[0007]
FIG. 11 shows a schematic configuration as an optical pickup device. The objective lens holding device 1 is used together with a terminal plate 20, a yoke 21, magnets 22a and 22b, and the like. Terminals 8, 9, and 10 are joined to the distal ends of the support wires 23, 24, 25, and 26 that are erected on the terminal plate 20, so that the terminal plate 20 and each coil are electrically connected to each other. It is also supported. The yoke 21 and the magnets 22a and 22b form a magnetic circuit that generates a magnetic field that interlinks with each coil, generates an electromagnetic force by energizing the coil, and moves the objective lens holding device 1 in the focusing direction and the tracking direction. Can be displaced.
[0008]
There has also been proposed a configuration in which an annular protective member corresponding to a protector is mounted around an objective lens, and fixed to a lens holder with an adhesive (for example, see Patent Document 1). Also, a configuration has been proposed in which a protection member corresponding to a protector is mechanically locked from both sides of a lens holder on which an objective lens is mounted (for example, see Patent Document 2).
[0009]
[Patent Document 1]
JP 10-320802 A [Patent Document 2]
JP 2000-311363 A
[Problems to be solved by the invention]
In order to mount the protectors 11 and 12 as shown in FIG. 9, a space is required around the objective lens 2. For this reason, there is no problem if the lens holder 3 has a sufficient space, but it is difficult to mount the lens holder 3 with a downsized lens holder. In general, the objective lens 2 and the protectors 11 and 12 are often fixed with an adhesive, but a structure for preventing the adhesive from flowing before it is hardened may be required. In the case of Patent Document 1, although the adhesive is applied to a portion that is opened to the side to prevent the adhesive from wrapping around the surface, it is difficult for the adhesive to flow downward from the side before the adhesive is cured. It is unknown how to prevent it. Patent Literature 2 only describes that a protection member corresponding to a protector is mechanically locked. If the protection member is not adhered, there is a possibility that a shift or the like may occur due to mechanical vibration or the like.
[0011]
In the objective lens holding device 1 shown in FIG. 9, a weir 3a and a rib 3b are formed on the surface of the lens holder 3 on which the objective lens 2 is mounted in order to prevent the adhesive from flowing out. An extra space is required to form the weir 3a and the rib 3b.
[0012]
SUMMARY OF THE INVENTION An object of the present invention is to provide an objective lens holding device that can be sufficiently miniaturized and can be easily fixed by bonding.
[0013]
[Means for Solving the Problems]
The present invention is an objective lens holding device that holds an objective lens close to the surface of an object that handles information optically,
A lens holder on which an objective lens is mounted on a surface facing the object;
A protector formed of a material softer than the objective lens and the lens holder, and mounted on the surface side facing the object with the lens holder so as to protrude from the objective lens,
An adhesive layer for simultaneously fixing the objective lens and the protector to the lens holder,
An objective lens holding device characterized in that a weir is formed around a surface of a lens holder facing an object and a protector, or with a protector, surrounding a radial outside of the objective lens.
[0014]
According to the present invention, the objective lens holding device includes a lens holder, a protector, and an adhesive layer for holding the objective lens close to the surface of an object that handles information optically. The lens holder has an objective lens mounted on a surface facing an object, and a protector formed of a material softer than the objective lens and the lens holder is mounted so as to protrude beyond the objective lens. The objective lens and the protector are fixed simultaneously with the adhesive layer. The weir surrounding the objective lens in the radial direction is formed around the surface of the lens holder facing the object and the protector, or with the protector, apply an adhesive to form an adhesive layer. Even so, runoff can be prevented by the weir. Since the protector forms part or all of the weir, the space required for the lens holder can be reduced, and the size can be reduced.
[0015]
Further, in the present invention, the protector is provided on both sides of the optical axis of the objective lens.
[0016]
In the present invention, since the protectors are provided on both sides of the optical axis of the objective lens, even if the objective lens holding device is tilted, any one of the protectors comes into contact with the object and prevents contact of the objective lens and the lens holder. it can.
[0017]
Further, in the present invention, the protector makes a round around the periphery of the objective lens, and protrudes toward the object on both sides of the optical axis of the objective lens.
[0018]
According to the invention, the protector can be integrated to prevent contact with the object on both sides of the objective lens.
[0019]
Further, in the present invention, the joint surface between the protector and the lens holder,
On one side of the protector or the lens holder, a protrusion protruding from the one side to the other side,
A concave portion with which the convex portion is fitted is formed on the other side, respectively.
By fitting the convex portion and the concave portion, temporary fixing before the application of the adhesive is possible.
[0020]
According to the present invention, on the joint surface between the protector and the lens holder, a convex portion protruding from one side and a concave portion in which the convex portion is fitted on the other side are formed. By fitting, the protector and the lens holder can be temporarily temporarily fixed. By mounting and bonding the objective lens to the lens holder to which the protector is temporarily fixed, the objective lens holding device can be easily assembled and fixed.
[0021]
Further, in the present invention, the convex portion and the concave portion are formed so as to allow attachment / detachment only in a predetermined direction in a fitted state and restrict displacement in a direction orthogonal to the one direction. Features.
[0022]
According to the present invention, the convex portion and the concave portion for temporarily fixing the protector and the lens holder allow attachment / detachment only in a predetermined direction in a fitted state, and restrict displacement in a direction orthogonal to the one direction. As a result, it is possible to assemble firmly in a temporarily fixed state.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a schematic configuration of an objective lens holding device 31 according to a first embodiment of the present invention. The objective lens holding device 31 holds the objective lens 32 with a lens holder 33. The tracking coils 34 and 35 and the focus coils 36 and 37 are wound around the lens holder 33, and terminals 38 and 39 for electrical connection and mechanical support are provided. The tracking coils 34 and 35, the focus coils 36 and 37, and the terminals 38 and 39 are equivalent to the tracking coils 4 and 5, the focus coils 6 and 7, and the terminals 8 and 9 in FIG. A terminal is also provided on the focus coil 37 side. The objective lens 32 is formed of a transparent synthetic resin or glass having good optical properties. The lens holder 33 is formed of a synthetic resin.
[0024]
The objective lens holding device 31 of the present embodiment mounts the objective lens 32 on the surface facing the object in order to hold the objective lens 32 close to the surface of the object such as an optical disk that handles information optically. The lens holder 33 is formed around the objective lens 32 and a material such as synthetic resin or rubber that is softer than the lens holder 33, and protrudes from the objective lens 32 toward the surface facing the object with the lens holder 33. Protectors 41 and 42 are mounted as described above. The objective lens 32 and the protectors 41 and 42 are simultaneously fixed to the lens holder 33 by the adhesive layer 43. The periphery of the surface of the lens holder 33 facing the object and the protectors 41 and 42 form a weir surrounding the objective lens 32 in the radial direction, and the adhesive layer 43 is held inside the weir. At a joint between the lens holder 33 and the protectors 41 and 42, a temporary fixing groove 45 and a temporary fixing ridge 46 are formed, respectively.
[0025]
FIG. 2 shows a cross-sectional configuration around the objective lens 32 in the objective lens holding device 1 of FIG. In the objective lens holding device 31 of FIG. 1, protectors 41 and 42 formed of a material softer than the objective lens 32 and the lens holder 33 are mounted so that the tips 41 a and 42 a protrude beyond the objective lens 32. . The objective lens 32 and the protectors 41 and 42 are simultaneously fixed by the adhesive layer 43. The periphery 33a of the surface of the lens holder 33 facing the object and the tips 41a and 42a of the protectors 41 and 42 form a weir surrounding the objective lens 32 in the radial direction, so that the adhesive layer 43 is formed. Even if an adhesive is applied for the purpose, the flow can be prevented by the weir. Since the protectors 41 and 42 form a part of the weir, the space required for the lens holder 33 can be reduced, and the size can be reduced.
[0026]
The protectors 41 and 42 are provided on both sides of the optical axis of the objective lens 32. Thus, even if the objective lens holding device 1 is tilted, one of the protectors 41 and 42 comes into contact with the object, and the contact between the objective lens 32 and the lens holder 33 can be prevented.
[0027]
FIG. 3 shows a state in which one of the protectors 41 is removed before the adhesive for forming the adhesive layer 43 is applied in the objective lens holding device 1 of FIG. The temporary fixing ridges 46 of the protector 41 can be temporarily fixed by fitting into the temporary fixing grooves 45 of the lens holder 33. In addition, the convex portion such as the temporary fixing ridge 46 may be formed on the joint surface between the protectors 41 and 42 and the lens holder 33, and the other from one side of the protectors 41 and 42 or the lens holder 33 to the other side. It only has to project to the side. On the other side, a recess such as the temporary fixing groove 45 may be formed. A convex portion protruding from one side and a concave portion to which the convex portion fits are formed on the other side. By fitting the convex portion into the concave portion, the protectors 41 and 42 and the lens holder 33 are mechanically connected. It can be temporarily fixed temporarily. The objective lens holding device 31 can be easily assembled and fixed by attaching the objective lens 32 to the lens holder 33 to which the protectors 41 and 42 are temporarily fixed and applying and bonding an adhesive. This is the same in other embodiments.
[0028]
FIG. 4 shows a schematic configuration of an objective lens holding device 51 according to a second embodiment of the present invention. In the present embodiment, portions corresponding to the embodiment of FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted. In this embodiment, the adhesive layer 43 is formed in the same manner as in the embodiment of FIG. 1, but the illustration is omitted. The same applies to each embodiment described below.
[0029]
In the present embodiment, the distal end 52a of the protector 52 makes a round around the objective lens 32 and protrudes toward the object on both sides of the optical axis of the objective lens 32. Thereby, the protector 52 can be integrated, and contact with the object on both sides of the objective lens 32 can be prevented.
[0030]
FIG. 5 shows a schematic configuration of an objective lens holding device 61 according to a third embodiment of the present invention. In the present embodiment, the protectors 65 and 66 mounted on both sides of the lens holder 63 are temporarily fixed using a step generated in the tracking coils 34 and 35. That is, the protectors 65 and 66 are temporarily fixed by the temporary fixing ridges 67 projecting downward. The formation of the weir by the tips 65a, 66a of the protectors 65, 66 and the periphery 63a of the lens holder 63 is the same as in the embodiment of FIG.
[0031]
FIG. 6 shows a schematic configuration of an objective lens holding device 71 according to a fourth embodiment of the present invention. In the present embodiment, the integrated protectors 75 mounted on both sides of the periphery of the lens holder 63 are temporarily fixed by using steps generated in the tracking coils 34 and 35. That is, the protector 75 is temporarily fixed by the temporary fixing ridge 77 projecting downward. The formation of the weir by the tip 75a of the protector 75 is the same as that of the embodiment of FIG.
[0032]
FIG. 7 shows a schematic configuration of an objective lens holding device 81 according to a fifth embodiment of the present invention. In the present embodiment, the protectors 85 and 86 mounted on both sides of the lens holder 83 fit the temporary fixing protrusions 87 into the temporary fixing recesses 88 on the lens holder 83 side. In the present embodiment, the displacement in the direction 88b perpendicular to the attaching / detaching direction 89a can also be restricted during the temporary fixing. The tracking coils 34 and 35 are temporarily fixed by using a step generated in the portions. That is, in the fitted state, the temporary fixing projection 87 and the temporary fixing recess 88 allow attachment / detachment only in one predetermined direction 89a, and restrict displacement in a direction 89b orthogonal to the one direction 89a. Is formed. Thereby, the convex portion and the concave portion for temporarily fixing the protector 85 and the lens holder 83 allow attachment / detachment only in a predetermined direction in a fitted state, and restrict displacement in a direction orthogonal to the one direction. It can be firmly assembled in a temporarily fixed state. The formation of the weir by the tips 85a, 86a of the protectors 85, 86 and the periphery 83a of the lens holder 83 is the same as in the embodiment of FIG.
[0033]
FIG. 8 shows a schematic configuration of an objective lens holding device 91 according to a sixth embodiment of the present invention. In this embodiment, protectors 95 and 96 are mounted on both sides of the lens holder 93. The lens holder 93 has a temporary fixing protrusion 97 and can be fitted into a temporary fixing recess 98 formed on the protector 95 or 56 side. Similar to the embodiment of FIG. 7, it is possible to assemble firmly in a temporarily fixed state. The formation of the weir by the distal ends 95a, 96a of the protectors 95, 96 and the periphery 93a of the lens holder 93 is the same as in the embodiment of FIG.
[0034]
Although the case where the objective lens holding device is used in the optical pickup device has been described above, the present invention can be similarly used in a reading device for reading characters and bar codes.
[0035]
【The invention's effect】
As described above, according to the present invention, a weir is formed around the surface of the lens holder facing the object and the protector or with the protector so as to surround the radial outside of the objective lens, and the flow of the adhesive is performed by the weir. Therefore, the bonding can be easily performed, the space required for the lens holder can be reduced, and the size can be reduced.
[0036]
Further, according to the present invention, since the protectors are provided on both sides of the optical axis of the objective lens, even if the objective lens holding device is tilted, contact of the objective lens and the lens holder can be prevented.
[0037]
Further, according to the present invention, it is possible to prevent the contact with the object on both sides of the objective lens by integrating the protector.
[0038]
Further, according to the present invention, the convex portion is fitted into the concave portion at the joint surface between the protector and the lens holder, thereby temporarily temporarily fixing the protector and the lens holder, and easily assembling and fixing the objective lens holding device. be able to.
[0039]
Further, according to the present invention, the convex portion and the concave portion for temporarily fixing the protector and the lens holder are fitted to each other, detachment is allowed only in a predetermined direction, and displacement is restricted in a direction orthogonal to the one direction. It can be firmly assembled in a temporarily fixed state.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an external configuration of an objective lens holding device 31 according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view near the objective lens of FIG.
FIG. 3 is a perspective view showing a state where one protector 41 is removed from the objective lens holding device 31 of FIG. 1;
FIG. 4 is a perspective view showing an external configuration of an objective lens holding device 51 according to a second embodiment of the present invention.
FIG. 5 is a perspective view illustrating an external configuration of an objective lens holding device 61 according to a third embodiment of the present invention.
FIG. 6 is a perspective view showing an external configuration of an objective lens holding device 71 according to a fourth embodiment of the present invention.
FIG. 7 is a perspective view illustrating an external configuration of an objective lens holding device 81 according to a fifth embodiment of the present invention.
FIG. 8 is a perspective view showing an external configuration of an objective lens holding device 91 according to a sixth embodiment of the present invention.
FIG. 9 is a perspective view showing an external configuration of a conventional objective lens holding device 1.
10 is a simplified cross-sectional view showing a schematic configuration of an optical pickup device using the objective lens holding device 1 of FIG.
FIG. 11 is a simplified perspective view showing a schematic configuration of an optical pickup device using the objective lens holding device 1 of FIG.
[Explanation of symbols]
31, 51, 61, 71, 81, 91 Objective lens holding device 32 Objective lenses 33, 63, 83, 93 Lens holders 41, 42, 52, 65, 66, 75, 85, 86, 95, 96 Protector 43 Adhesive Layer 45 Temporary fixing grooves 46, 67, 77 Temporary fixing protrusions 87, 98 Temporary fixing protrusions 88, 97 Temporary fixing recesses

Claims (5)

An objective lens holding device that holds an objective lens close to the surface of an object that handles information optically,
A lens holder on which an objective lens is mounted on a surface facing the object;
A protector formed of a material softer than the objective lens and the lens holder, and mounted on the surface side facing the object with the lens holder so as to protrude from the objective lens,
An adhesive layer for simultaneously fixing the objective lens and the protector to the lens holder,
An objective lens holding device, wherein a weir is formed around a surface of a lens holder facing an object and a protector, or the protector surrounds a radial outside of the objective lens. The objective lens holding device according to claim 1, wherein the protector is provided on both sides of the optical axis of the objective lens. 2. The objective lens holding device according to claim 1, wherein the protector makes a round around the periphery of the objective lens and protrudes toward the object on both sides of the optical axis of the objective lens. 3. On the joint surface between the protector and the lens holder,
On one side of the protector or the lens holder, a protrusion protruding from the one side to the other side,
A concave portion with which the convex portion is fitted is formed on the other side, respectively.
The objective lens holding device according to any one of claims 1 to 3, wherein the convex portion and the concave portion are fitted to each other, whereby temporary fixing before applying the adhesive is possible. The said convex part and the said concave part are formed so that attachment / detachment is permitted only in one predetermined direction in a fitting state, and restricts displacement about the direction orthogonal to this one direction. 5. The objective lens holding device according to 4.

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