JP2006107654A - Objective lens inspection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an objective lens inspection apparatus for optical pickup in which mechanical external force is not applied to the drive mechanism of focusing and tracking when the objective lens is changed, and durability and reliability of inspection are secured, and the objective lens can be easily and quickly changed, and the objective lens can be inspected quickly in a short period of time. <P>SOLUTION: In the objective lens inspection apparatus which has a holder having a pressurizing member pressurizing and holding an objective lens and a drive means shifting the holder in a direction parallel to an optical axis and a direction orthogonal to the optical axis, and in which the objective lens can be changed, a holder fixing member which can be moved relatively to a first position separated from the holder and a second position engaged with the holder is provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an objective lens inspection apparatus for inspecting an objective lens for an optical pickup.

  2. Description of the Related Art Conventionally, an optical pickup that records and / or reproduces information on an optical disk such as a DVD (Digital Versatile Disk) or a CD (Compact Disk) is known. These optical pickups are provided with an objective lens for focusing a laser beam having a predetermined wavelength on a signal recording area of the disc.

  This optical pickup objective lens is subjected to quality inspection during the manufacturing process. This quality inspection includes measurement of transmitted wavefront aberration of the objective lens and quality evaluation for confirming recording and / or reproduction performance with an actual optical pickup.

As an objective lens inspection device for quality evaluation with this actual optical pickup, when a holding member that holds an objective lens is fixed to a holder with a fixing screw, and the objective lens that is the object to be inspected is replaced, this fixing screw Has been disclosed in which the holding member is removed (see, for example, Patent Document 1).
JP 2000-315334 A

  Although the objective lens inspection apparatus described in Patent Document 1 described above can exchange lenses, each time the objective lens is replaced, the fixing screw must be loosened or tightened, and many objective lenses are inspected during the process. There is a problem that it is extremely inefficient.

  Furthermore, the holder on which the objective lens is placed and the holding member and the fixing screw are fixed is held in a flexible manner so as to be displaceable for focusing and tracking, and the fixing screw is tightened when the objective lens is replaced. Alternatively, there is a problem that an excessive force is applied to loosen, thereby damaging the focusing and tracking drive mechanism and causing a failure.

  In view of the above problems, the present invention prevents an external mechanical force from being applied to a focusing and tracking drive mechanism when exchanging an objective lens, and ensures durability and reliability of inspection, and an easy and quick objective lens. It is an object of the present invention to obtain an inspection apparatus for an objective lens for an optical pickup capable of exchanging the above-described lenses and efficiently inspecting many objective lenses in a short time.

  The above object is solved by the following configuration.

  1) a holder having a lens placement portion for placing an objective lens, a pressing member for pressing and holding the objective lens placed on the lens placement portion, and a direction parallel to the optical axis of the objective lens And a drive means for displacing the objective lens in a direction perpendicular to the optical axis, and the objective lens inspection apparatus in which the objective lens can be exchanged is separated from the holder and does not interfere with the displacement of the holder. An objective lens inspection device comprising: a holder fixing member that can move relative to the position of the second position and a second position that engages with the holder and fixes the holder.

  2) The holder fixing member can be relatively moved to a third position closer to the objective lens than the second position, and with the movement from the second position to the third position, The objective lens inspection device according to 1) configured to release the pressing and holding of the pressing member.

  3) The objective lens inspection apparatus according to 1), further comprising a pressing release member that releases the pressing holding of the pressing member.

  4) The objective lens inspection device according to 3), wherein the holder is supported by a plurality of wires, and the movement direction of the holder fixing member and the movement direction of the pressing release member are arranged substantially orthogonal to each other.

  5) The objective lens inspection device according to any one of 1) to 4), wherein the pressing member is formed so as to press a symmetric position across the optical axis of the objective lens.

  6) The lens mounting portion has a through hole, a part of the objective lens is inserted and placed in the through hole, and an insertion length of the objective lens into the through hole is 0.2 mm to 0. The objective lens inspection device according to any one of 1) to 5), which is 6 mm.

7) When the pressing force of the pressing member is F and the product of the mass of the objective lens and the maximum acceleration applied to the holder is f,
3 ≦ F / f <8
1) to 6) objective lens inspection device.

  Relative movement between the first position of the present invention that is separated from the holder on which the objective lens is placed and does not interfere with the displacement of the holder, and the second position that engages with the holder and fixes the holder so that it cannot be displaced is possible. A holder fixing member, that is, when the objective lens is inspected, the holder fixing member is set to the first position, the holder is driven and displaced to inspect the objective lens, and when the objective lens is replaced, the holder fixing member is set to the second position. By moving and fixing the holder firmly, it is possible to eliminate the problem that harmful mechanical external force is applied to the focusing and tracking drive mechanism when changing the objective lens, and there is no damage or failure of the drive mechanism, and the inspection device It is possible to improve the durability and the reliability of inspection results.

  In addition, the holder fixing member can be moved relative to the third position closer to the objective lens than the second position, and the holding of the pressing member is released with the movement from the second position to the third position. In addition to the above-described effects, there is no troublesome operation such as screw loosening or tightening in addition to the above-described effects when the objective lens is replaced. The lenses can be exchanged quickly and easily, and a large number of objective lenses can be inspected in a short time, and the inspection work efficiency can be improved.

  Further, when the holder is supported by a plurality of wires, the pressing release member releases the pressing of the pressing member by arranging the moving direction of the holder fixing member and the moving direction of the press releasing member substantially orthogonal to each other. In doing so, the load on the wire can be reduced.

  In addition, by pressing the symmetrical position with the optical axis of the objective lens sandwiched by the pressing member, it is possible to prevent the objective lens from resonating due to the deviation of the objective lens pressing position during focusing and tracking drive in the high frequency region. Reliability can be improved.

  Further, the lens placement portion has a through hole, and a part of the objective lens is inserted and placed in the through hole, and the insertion length of the objective lens into the through hole is in a range of 0.2 mm to 0.6 mm. Thus, it is fixed steadily at the time of mounting, it is easy to remove at the time of removal, and it is only necessary to lift the pressing member slightly at the time of releasing the pressure, and the amount of deformation within the elastic deformation region of the pressing member can be obtained.

  In addition, when the pressing force of the pressing member is F and the product of the mass of the objective lens and the maximum acceleration applied to the holder is f, the pressing member is formed so as to satisfy 3 ≦ F / f <8. And higher-order resonance of the holder can be prevented, and the reliability of the inspection result can be improved.

  Hereinafter, the present invention will be described in detail with reference to embodiments, but the present invention is not limited thereto.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described. In the present embodiment, the present invention is applied to a type in which a holder on which an objective lens as a subject is placed is supported by a wire.

  FIG. 1 is a diagram showing an objective lens inspection apparatus 100 according to the first embodiment.

  An objective lens inspection apparatus 100 shown in FIG. 1 includes a holder 2 having a lens placement portion on which an objective lens 1 as a subject is placed, and an optical pickup portion 40 provided with a drive portion that drives the holder 2 to be displaced. The holder fixing member 50 and the slide base 60 on which the optical pickup unit 40 and the holder fixing member 50 are placed are configured.

  The optical pickup unit 40 includes the holder 2 and the support member 7 as main components. The objective lens 1 having a flange portion 1f with O as the optical axis is inserted into a through-hole portion (not shown) of the holder 2, and the objective lens 1 The flange portion 1f is fixed to the holder 2 by a pressing member 8 formed of an elastic body such as a leaf spring. The pressing member 8 is fixed to the holder 2 by a fixing screw 9.

  The pressing member 8 is not limited to this, and may be fixed by caulking, adhesion, insertion, or the like, or may be integrally formed with the holder.

  In the present embodiment, a lens surface and a flange portion that are integrally formed and a lens frame that has a flange portion and that incorporates a lens are collectively referred to as an objective lens 1.

  The holder 2 is supported by four flexible wires 6 extending from the support member 7, and the holder 2 can move in the optical axis direction and the optical axis orthogonal direction within a predetermined range using the wire 6 as a suspension. In the present embodiment, the holder 2 is described as being supported by four wires 6. However, the present invention is not limited to this, and the holder 2 may be supported by six or eight wires.

  A focus driving coil 13 is wound around the outer periphery of the holder 2, and an actuator constituted by a tracking driving coil 14 (not shown) in a magnetic circuit constituted by the outer yoke 4, the inner yoke 5 and the magnet 3. Is arranged. By supplying power to these coils, the holder 2 can swing in two directions: a direction of the optical axis O (focusing direction) and a direction orthogonal to the optical axis (tracking direction). Further, power is supplied to these coils via a wire 6.

  The holder 2 is preferably formed with a mass sufficiently larger than the mass of the objective lens 1. By doing so, it is possible to reduce the amount of movement of the center of gravity when used for inspection of different objective lenses, and it is possible to provide a versatile inspection apparatus that prevents pitching due to a bias in balance.

  Further, holes 15 are formed at two locations on the surface of the holder 2 on the holder fixing member 50 side with the outer yoke 4 interposed therebetween.

  Note that the pressing member 8 is formed so as to press a symmetrical position across the optical axis O of the objective lens 1 as illustrated. By doing so, the holder 2 is driven, and at the time of focusing and tracking at a high frequency, resonance of the objective lens due to the deviation of the objective lens pressing position can be prevented.

  The holder fixing member 50 is guided and slidable by a guide groove 61 formed in the slide base 60. When the holder fixing member 50 is moved from the illustrated position along the guide groove 61 to the optical pickup unit 40 side, the two engaging portions 50k that engage with the two hole portions 15 formed in the holder 2 are provided. Is formed. The tip of the engaging portion 50k is formed in a conical shape as shown in the figure so that the engagement can be smoothly performed even if the hole portion 15 is slightly displaced. The engaging portion 50k may be formed by processing a bar and planting it on the holder fixing member 50, or may be formed integrally with the holder fixing member 50.

  Further, it is preferable to form a chamfer or the like on the hole 15 side of the holder so that the engagement with the engagement portion 50k can be smoothly performed, but either one may be used.

  Further, the holder fixing member 50 has a clearance between the distal end portion 8s of the pressing member 8 and the holder 2 when the engaging portion 50k is further engaged with the hole portion 15 of the holder 2 and further approaches the objective lens 1. An inclined portion 50s to be inserted into is integrally formed.

  The slide base 60 on which the optical pickup unit 40 and the holder fixing member 50 are placed is supported by a main guide shaft 62 and a sub guide shaft 63 of a lead screw, and in the guide axis direction by rotation of the lead screw which is the main guide shaft 62. It is made movable.

  The slide base 60 is assembled with a laser light source that emits laser light to the objective lens 1, a light receiving portion that receives light returned from the optical disk, and an optical block 64 that includes optical members that form these optical paths. It has been.

  Although not shown, an optical disk is disposed above the objective lens 1 and the objective lens is inspected. The optical disk is held on a known disk table by a clamp member, and is driven to rotate at a predetermined rotational speed by a spindle motor and a drive controller.

  The above is the schematic configuration of the objective lens inspection apparatus 100 according to the first embodiment.

  Next, the operation of the objective lens inspection apparatus 100 when the objective lens is replaced will be described.

  FIG. 2 is a diagram schematically showing the relative positional relationship between the holder 2 and the holder fixing member 50 of the objective lens inspection apparatus 100 and the function of the holder fixing member 50. This figure is a schematic view showing only the holder 2 and the holder fixing member 50 extracted.

  1A shows a state when the holder fixing member 50 is separated from the holder 2 and is in a position where it does not interfere with the displacement drive of the holder 2, as in FIG.

  As shown in the figure, a flange portion 1 f of an objective lens 1 (not shown) as a subject is pressed and fixed to a holder 2 by a pressing member 8 fixed by a fixing screw 9. In this state, the holder 2 is oscillated and displaced in two directions of the focusing direction and the tracking direction, and the objective lens 1 is inspected. The position of the holder fixing member 50 shown in FIG.

  When the inspection of the objective lens 1 is completed, the main guide shaft 62, which is a lead screw, is rotated, the slide base 60 is moved (see FIG. 1), and retracted from the lower surface of the optical disk (not shown). Thereafter, the objective lens 1 is exchanged.

  FIGS. 5B and 5C show the relative positional relationship between the holder fixing member 50 and the holder 2 when the objective lens 1 is replaced.

  As shown in FIG. 4B, the holder fixing member 50 is moved from the first position along the guide groove 61 formed in the slide base 60 (see FIG. 1), and the engaging portion 50k is moved to the holder 2. It is inserted into the formed hole 15 and engaged. The position of the holder fixing member 50 shown in FIG. 4B is referred to as a second position.

  Due to the movement of the holder fixing member 50 to the second position, the holder 2 is firmly supported by the holder fixing member 50 instead of being supported by the flexible wire 6 described above. In this state, even if the fixing screw 9 is loosened, the pressing member 8 is removed, and the objective lens 1 is replaced, the holder 2 is firmly supported, which is harmful to the focusing and tracking displacement drive mechanism. The problem of applying external force can be solved, and the breakage and failure of the drive mechanism can be eliminated.

  The holder fixing member 50 is moved from the second position shown in FIG. 5B to a position closer to the objective lens 1 and is in the state shown in FIG.

  At this time, as shown in FIG. 5C, the inclined portion 50s formed on the holder fixing member 50 pushes up the tip portion 8s of the pressing member 8 and releases the pressing of the pressing member 8 on the flange portion 1f. The position of the holder fixing member 50 shown in FIG. 5C is referred to as a third position.

  By moving the holder fixing member 50 to the third position, the holder 2 is firmly supported, while the pressing of the pressing member 8 on the flange portion 1f is released, so that the objective lens 1 can be replaced quickly and easily. Thus, a large number of objective lenses can be inspected in a short time, and the inspection work efficiency can be improved.

  Note that the holder fixing member described with reference to FIG. 1 may be separated into a holder fixing member 50 having an engaging portion 50k and a press releasing member having an inclined portion 50s.

  FIG. 3 is a schematic diagram showing the relative positional relationship and the respective functions when the holder fixing member 50 having only the engaging portion 50k and the press releasing member having the inclined portion 50s are separated.

  The holder fixing member 50 having the engaging portion 50k and the pressing release member 51 having the inclined portion 50s shown in the figure move along the same guide groove 61, and the holder fixing member 50 is disposed on the holder 2 side. Thereby, the press release member 51 is configured so that it cannot move to the holder 2 side before the holder fixing member 50.

  FIG. 6A is in the same state as FIG. The position of the holder fixing member 50 shown in FIG.

  As shown in FIG. 4B, the holder fixing member 50 is moved from the first position along the guide groove 61 formed in the slide base 60 (see FIG. 1), and the engaging portion 50k is moved to the holder 2. It is inserted into the formed hole 15 and engaged. The position of the holder fixing member 50 shown in FIG. 4B is referred to as a second position.

  By the movement of the holder fixing member 50 to the second position, the holder 2 is firmly supported, not supported by the flexible wire 6, and the same effect as described above can be obtained.

  Next, as shown in FIG. 5C, the pressing release member 51 in which the inclined portion 50s is formed moves along the guide groove 61, pushes up the distal end portion 8s of the pressing member 8, and the flange portion of the pressing member 8 Release the pressure to 1f.

  By releasing the pressing to the flange portion 1f by the pressing release member 51 and firmly fixing the holder 2 by the holder fixing member 50, the objective lens 1 can be replaced quickly and easily. Inspection can be performed and inspection work efficiency can be improved.

  In the above-described embodiment shown in FIG. 3, the example in which the holder fixing member 50 and the press releasing member 51 are configured to move in the same direction along the same guide groove has been described. And the pressing release member 51 may be arranged so that the moving directions thereof are substantially orthogonal. By doing in this way, when the press release member 51 cancels the press holding of the press member 8, the load applied to the wire 6 can be reduced, which is more preferable. Alternatively, the holder fixing member 50 may be provided on each of the opposing side surfaces of the holder 2 so as to move and fix the holder 2 from two directions substantially perpendicular to the moving direction of the press release member 51.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described. In the present embodiment, the present invention is applied to a so-called shaft sliding type.

  FIG. 4 is a diagram showing an objective lens inspection apparatus 200 according to the second embodiment.

  An objective lens inspection apparatus 200 shown in FIG. 1 includes a holder 2 having a lens placement portion on which an objective lens 1 as a subject is placed, and an optical pickup portion 140 including a drive portion that drives the holder 2 to be displaced. It is composed of a holder fixing member 150 and a slide base 60 on which these are mounted. Since the slide base 60 is the same as that in FIG. 1, the parts other than the upper surface are omitted, and the optical pickup unit 140 and the holder fixing member 150 are shown. Is.

  The optical pickup unit 140 includes the holder 20 and the support member 30 as main components, and the objective lens 1 having a flange portion 1f with O as the optical axis is inserted into a through-hole portion (not shown) of the holder 20 so that the objective lens 1 The flange portion 1f is fixed to the holder 20 by pressing a pressing member 8 formed of an elastic body such as a leaf spring. The pressing member 8 is fixed to the holder 20 by a fixing screw 9.

  The pressing member 8 is not limited to this, and may be fixed by caulking, adhesion, insertion, or the like, or may be integrally formed with the holder.

  Also in the present embodiment, the objective lens 1 is collectively referred to as one in which the lens surface and the flange portion are integrally molded and the one in which the lens is incorporated in the lens frame having the flange portion.

  Although not shown, the holder 20 is provided with an insertion hole parallel to the optical axis O of the objective lens 1, and the support member 30 is formed with an axis that fits into the insertion hole. The holder 20 slides in this axial direction and is rotationally displaced about the axis so that focusing and tracking are performed.

  Focusing coils 25 constituting the biaxial actuator 21 are arranged opposite to each other at two notch positions on the outer peripheral portion of the holder 20. An annular tracking coil 26, a U-shaped yoke 27 having one end inserted into the inner peripheral portion of the focusing coil 25, the focusing coil 25 and the tracking coil 26 are disposed on the outer peripheral portion of the focusing coil 25. And a driving magnet 28 provided on the yoke 27 so as to oppose each other. A neutral magnetic body for positioning the holder 20 at the initial position in the focusing direction is disposed at the center of the tracking coil 26. The above-mentioned insertion hole is formed in the approximate center of these opposing actuator parts.

  The holder 20 is preferably formed with a mass sufficiently larger than the mass of the objective lens 1. By doing so, it is possible to reduce the amount of movement of the center of gravity when used for inspection of different objective lenses, and it is possible to provide a versatile inspection apparatus that prevents pitching due to a bias in balance.

  Further, the holder 20 is formed with a tongue-shaped protrusion 20t. As shown in the drawing, the pressing member 8 is formed so as to press a symmetrical position with the optical axis O of the objective lens 1 interposed therebetween, and the tip 8s is formed to be in the protruding direction of the protruding portion 20t.

  The holder fixing member 150 is guided by a guide groove 61 formed in the slide base 60 and is slidable. When the holder fixing member 150 moves from the illustrated position along the guide groove 61 to the optical pickup unit 140 side, the holder fixing member 150 engages with a protrusion 20t formed on the holder 20 and engages with a U-shaped through hole. A joint portion 150k is formed. The engaging portion 150k is preferably formed with rounded corners, chamfered portions, etc. at the insertion port of the protruding portion 20t, and the tip of the protruding portion 20t is tapered or arcuate as shown. It is preferable.

  Further, the holder fixing member 150 has a gap between the distal end portion 8s of the pressing member 8 and the holder 20 when the engaging portion 150k is further engaged with the protruding portion 20t of the holder 20 and further approaches the objective lens 1. An inclined portion 150s to be inserted into is integrally formed.

  The slide base 60 on which the optical pickup unit 140 and the holder fixing member 150 are mounted is similar to that illustrated in FIG. 1 although not shown, and is supported by the main guide shaft and the sub guide shaft of the lead screw. It can be moved in the direction of the guide shaft by the rotation of the screw. The slide base is assembled with a laser light source that emits laser light to the objective lens 1, a light receiving portion that receives light returned from the optical disk, and an optical block that includes optical members that form these optical paths. An optical disk is arranged above 1, and the objective lens is inspected. The optical disk is held on a known disk table by a clamp member, and is driven to rotate at a predetermined rotational speed by a spindle motor and a drive controller.

  The above is the schematic configuration of the objective lens inspection apparatus 200 according to the second embodiment.

  Next, the operation of the objective lens inspection apparatus 200 when the objective lens is replaced will be described.

  FIG. 5 is a diagram schematically showing the relative positional relationship between the holder 20 and the holder fixing member 150 of the objective lens inspection apparatus 200 and the function of the holder fixing member 150. This figure is a schematic diagram showing only the holder 20 and the holder fixing member 150 extracted. In addition, the holder fixing member 150 is shown in the cross section cut | disconnected by FF line shown in FIG.

  4A shows a state in which the holder fixing member 150 is separated from the holder 20 and is in a position where it does not interfere with the displacement drive of the holder 20, as in FIG.

  As shown in the figure, a flange portion 1 f of an objective lens 1 (not shown) as a subject is pressed and fixed to a holder 20 by a pressing member 8 fixed by a fixing screw 9. In this state, the holder 20 is driven to swing and move in two directions of the focusing direction and the tracking direction, and the objective lens 1 is inspected. The position of the holder fixing member 150 shown in FIG.

  When the inspection of the objective lens 1 is completed, the slide base 60 is moved and retracted from the lower surface of the optical disk (not shown). Thereafter, the objective lens 1 is exchanged.

  FIGS. 5B and 5C show the relative positional relationship between the holder fixing member 150 and the holder 20 when the objective lens 1 is replaced.

  As shown in FIG. 4B, the holder fixing member 150 is moved from the first position along the guide groove 61 formed in the slide base 60 (see FIG. 4), and the engaging portion 150k is moved to the holder 20. It is inserted and engaged with the formed protrusion 20t. The position of the holder fixing member 150 shown in FIG. 4B is referred to as a second position.

  Due to the movement of the holder fixing member 150 to the second position, the holder 20 is not supported by the magnetic force of the iron piece 29 but is firmly supported by the holder fixing member 150. In this state, for example, even if the fixing screw 9 is loosened and the pressing member 8 is removed and the objective lens 1 is replaced, the holder 20 is firmly supported, which is detrimental to the focusing and tracking displacement drive mechanism. The problem of applying external force can be solved, and the breakage and failure of the drive mechanism can be eliminated.

  The holder fixing member 150 is moved from the second position shown in FIG. 2B to a position closer to the objective lens 1 and is in the state shown in FIG.

  At this time, as shown in FIG. 5C, the inclined portion 150s formed on the holder fixing member 150 pushes up the tip end portion 8s of the pressing member 8, and the pressing of the pressing member 8 on the flange portion 1f is released. The position of the holder fixing member 150 shown in FIG. 5C is referred to as a third position.

  By moving the holder fixing member 150 to the third position, the holder 20 is firmly supported and the pressing of the pressing member 8 to the flange portion 1f is released, so that the objective lens 1 can be replaced quickly and easily. Thus, a large number of objective lenses can be inspected in a short time, and the inspection work efficiency can be improved.

  Also in this example, as in the case described with reference to FIG. 3 of the first embodiment, the holder fixing member 150 shown in FIG. 4 is released from the press of the holder fixing member having the engaging portion 150k and the inclined portion 150s. Of course, the members may be separated.

  In the first and second embodiments described above, the slide base is retracted from the optical disk and the objective lens is exchanged. However, the optical disk can be retracted and the slide base is fixed. Of course, it is also possible. Moreover, although demonstrated with the example comprised so that a holder fixing member might be moved to the holder side, the drive part containing a holder may be moved and the holder and the holder fixing member should just be movable relatively It is.

  Further, by using the pressing release member to release the pressing member, the pressing member is not pushed up by a predetermined amount or more, and a failure such as plastic deformation of the pressing member can be prevented.

  Further, since the objective lens inspection apparatus of the present invention can easily replace the objective lens, it can be applied not only as an objective lens inspection apparatus but also to a disk inspection apparatus by appropriately selecting a light source to be used. Can be high.

  FIG. 6 is a schematic cross-sectional view showing a state in which a part of the objective lens 1 is inserted and placed in a through hole formed in the holder.

  As shown in the figure, the holder 2 shown in FIG. 1 or the holder 20 shown in FIG. 4 has a through hole through which laser light passes, and a part of the objective lens 1 of the subject is inserted into the through hole. The flange portion 1f is pressed and fixed by a pressing member (not shown). D shown in the figure indicates the insertion length to be inserted into the through hole portion of the objective lens 1.

  In order to facilitate insertion and removal of the objective lens 1 in the through-hole portion, as shown in FIG. C, chamfering or rounding is formed at the through-hole entrance of the holders 2 and 20, or the portion where the objective lens 1 is inserted is formed. It is necessary to form a chamfer or rounded corner at the tip. This amount needs to be about 0.1 mm. Moreover, in order to position the objective lens 1 by fitting, about 0.1 mm is required as a length of a fitting part. That is, the insertion length D of the objective lens 1 into the through hole is required to be at least about 0.2 mm.

  On the other hand, if this insertion length is set to be large, the amount of pushing up the pressing member at the time of releasing the pressure must be increased, and if the amount exceeds the elastic deformation region of the pressing member formed by a leaf spring or the like, The function cannot be demonstrated.

  That is, the insertion length D of the objective lens into the through hole is preferably set to 0.2 mm to 0.6 mm.

  When driving the high-frequency frequency in the focusing direction and tracking direction using the objective lens inspection apparatus described above, there is a case where the objective lens is not fixed and the test result is not reliable. .

  This is considered to be because higher-order resonance occurs at a pressing force of the degree obtained by the product of the mass of the objective lens and the maximum acceleration 25G applied thereto. On the other hand, in order to increase the pressing force, it is necessary to increase the plate thickness, or to bring the action point and the support point closer to each other.When the thickness is excessively increased or approached, the pressing member is pushed up to release the pressure. It will cause plastic deformation. The inventor conducted the following experiment in order to obtain a suitable pressing force range of the pressing member.

  The setting conditions are as follows.

Objective lens inspection device used: having an axial sliding type drive unit shown in FIG. 4 Objective lens mass: 2 g
Pressing force of the pressing member: 5 types of 0.061N to 0.4N The above pressing members having the above 5 types of pressing force were used to examine whether high-order resonance occurred and whether the pressing member was plastically deformed.

  FIG. 7 is a table showing the experimental results. The F / f ratio is shown in the rightmost column in the figure, where F is the pressing force and f is the product of the mass of the objective lens and the maximum acceleration. Note that f is 0.049N, calculated by f = mass × maximum acceleration (25G).

  As shown in the figure, high-order resonance is not generated when the pressing force is 0.154 N or more, while plastic deformation of the pressing member is generated when the pressing force is 0.200 N.

  From the above results, it is preferable to set 3 ≦ F / f <8, where F is the pressing force of the pressing member and f is the product of the mass of the objective lens and the maximum acceleration applied to the holder. understood. Moreover, it is more preferable to set 3 ≦ F / f ≦ 4 in consideration of the reduction of the force applied to the inclined portion at the time of releasing the pressure and the individual difference variation of the pressing member.

It is the figure which showed the objective lens test | inspection apparatus 100 which concerns on 1st Embodiment. It is the figure which showed typically the relative positional relationship of the holder of the objective lens test | inspection apparatus 100, and a holder fixing member, and the function of a holder fixing member. It is a schematic diagram which shows each relative positional relationship and each function at the time of comprising separately with the holder fixing member which has only an engaging part, and the press release member which has an inclination part. It is the figure which showed the objective lens test | inspection apparatus 200 which concerns on 2nd Embodiment. It is the figure which showed typically the relative positional relationship of the holder of the objective lens test | inspection apparatus 200 and a holder fixing member, and the function of a holder fixing member. It is a schematic sectional drawing which shows the state which inserted and mounted some objective lenses in the through-hole formed in the holder. The experimental results are tabulated.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Objective lens 2 Holder 3 Magnet 4 Outer yoke 5 Inner yoke 6 Wire 7 Support member 8 Press member 13 Focus drive coil 14 Tracking drive coil 15 Hole 50 Holder fixing member 60 Slide base 62 Main guide shaft 63 Sub guide shaft 64 Optical block

Claims (7)

A holder having a lens placement portion for placing the objective lens, a pressing member for pressing and holding the objective lens placed on the lens placement portion, and a direction parallel to the optical axis of the objective lens and the holder An objective lens inspection apparatus having a drive means for displacing in a direction perpendicular to the optical axis, wherein the objective lens is replaceable,
A holder fixing member that is relatively movable between a first position that is separated from the holder and does not interfere with the displacement of the holder, and a second position that engages with the holder and fixes the holder; Objective lens inspection device. The holder fixing member is movable relative to a third position closer to the objective lens than the second position;
The objective lens inspection device according to claim 1, wherein the holding of the pressing member is released in accordance with the movement from the second position to the third position. The objective lens inspection apparatus according to claim 1, further comprising a press release member that releases the press holding of the press member. The objective lens inspection apparatus according to claim 3, wherein the holder is supported by a plurality of wires, and is arranged so that a movement direction of the holder fixing member and a movement direction of the press release member are substantially orthogonal to each other. 5. The objective lens inspection device according to claim 1, wherein the pressing member is formed so as to press a symmetric position across the optical axis of the objective lens. The lens placement portion has a through hole, and a part of the objective lens is inserted and placed in the through hole, and the insertion length of the objective lens into the through hole is 0.2 mm to 0.6 mm. The objective lens inspection device according to claim 1, wherein the objective lens inspection device is provided. When the pressing force of the pressing member is F and the product of the mass of the objective lens and the maximum acceleration applied to the holder is f,
3 ≦ F / f <8
The objective lens inspection device according to claim 1, wherein:

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