WO2007017997A1

WO2007017997A1 - Optical pickup

Info

Publication number: WO2007017997A1
Application number: PCT/JP2006/313157
Authority: WO
Inventors: Tsukasa Yamada; Soumei Takahashi; Akihiro Yoshizawa
Original assignee: Mitsumi Electric Co., Ltd.
Priority date: 2005-08-09
Filing date: 2006-06-30
Publication date: 2007-02-15
Also published as: JP2007048365A

Abstract

An optical pickup for a thin optical disk device, in which the range of displacement of a lens holder can be limited when an excessive impact is applied to the optical disk device and the optical pickup. The optical pickup has an optical base, an objective lens drive device mounted on the optical base, and a cover (6) for covering the upper surface of the optical base. The objective lens drive device has a damper base fixed to the optical base, suspension wires (53, 54, 55) each supported at one end at the damper base, the lens holder (2) to which the other end of each of the suspension wires is fixed, an objective lens held at the lens holder (2), and a pair of bobbins (241) for a tracking coil, provided on a front side section of the lens holder (2). A first projection (71) projecting toward the outside of the lens holder (2) is provided on the bobbins (241). The displacement range of the lens holder (2) is limited when the first projection (71) collides with the cover (6).

Description

Specification

Optical pickup

Technical field

The present invention relates to an optical pickup used for an optical disc apparatus.

Background art

An optical pickup used in an optical disc apparatus includes an optical base capable of moving along the radial direction of the optical disc, an objective lens driving device mounted on the optical base, and laser light provided on the optical base. A laser light source that emits light, a photodetector that detects the laser light reflected by the optical disk, and an optical device that guides the laser light emitted from the laser light source to the optical disk and guides the laser light reflected by the optical disk to the light detector. A system and a cover covering the top surface of the optical base.

[0003] The objective lens driving apparatus is generally provided with an objective lens, a lens holder for holding the objective lens, and a plurality of actuator coils provided on the lens holder for displacing the lens holder! / And a magnet that forms a magnetic field for these actuator coils, a plurality of suspension wires that support the lens holder at one end, and a damper base that supports the other ends of the plurality of suspension wires. Yes.

In the objective lens driving device having the above-described configuration, the lens holder can be displaced by the interaction between the current supplied to the actuator coil and the magnetic field generated by the magnet. In other words, the objective lens held in the lens holder can be displaced to perform focusing control or tracking control.

[0005] In recent years, optical disk devices have been miniaturized, and in particular, ultra-thin optical disk devices called ultra slim types are used in notebook personal computers and the like. For this reason, the optical pickup mounted on such an optical disc apparatus is also miniaturized, and accordingly, the suspension wire supporting the lens holder of the objective lens driving device is made extremely thin.

[0006] When the optical disk device or the optical pickup is accidentally dropped during transport of the optical disk device or the optical pickup, an excessive impact is applied to the objective lens driving device. Wow. As a result, an undesirable displacement may occur in the lens holder that is supported on the damper base via the suspension wire so as to be displaceable. In particular, when the optical disk device or the optical pickup is transported, the optical disk is loaded and is in a state (non-loaded state). Therefore, when the lens holder collides with the optical disk, the lens holder is desirably used. No displacement can be limited. Since the ultra-slim type optical disc apparatus as described above uses an extremely thin suspension wire, an undesirable displacement of the lens holder becomes excessive, and the suspension is immediately caused by such an undesirable displacement. There was a problem that the wire was deformed.

Disclosure of the invention

[0007] The present invention has been made in view of the above-described problems. When an excessive impact or the like is applied to the objective lens driving device during conveyance of the optical disk device or the optical pickup, the displacement range of the lens holder is determined. It is an object of the present invention to provide an optical pickup for an optical disc apparatus capable of limiting the above.

In order to achieve the above object, an optical pickup of the present invention includes an optical base that can move along a radial direction of an optical disk, an objective lens driving device mounted on the optical base, A laser light source that emits laser light provided on an optical base, a photodetector that detects laser light reflected by the optical disk, and guides the laser light emitted from the laser light source to the optical disk and is reflected by the optical disk. In the optical pickup comprising: an optical system that guides the laser beam to the photodetector; and a cover that covers the upper surface side of the optical base, the objective lens driving device condenses the laser beam on an optical disk. An objective lens to be moved, an upper surface, a front side wall, a rear side wall, and left and right side portions, the lens holder holding the objective lens on the upper surface, and a front A pair of actuator coil bobbins provided on the front side wall of the lens holder, and a plurality of suspension wires that have one end fixed to the left right side of the lens holder and support the lens holder; A damper base that supports the other end of each of the plurality of suspension wires, and the actuator coil bobbin is not loaded with an optical disc protruding outward in the orthogonal direction of the front side wall of the lens holder. A first protrusion for preventing displacement is provided, and the first protrusion for preventing displacement when the optical disk is not loaded is connected to the cover. The collision range restricts a displacement range of the lens holder.

[0009] According to the present invention having the above-described configuration, the actuator coil bobbin is provided with the first protrusion for preventing displacement when the optical disk is not loaded, protruding outward in the orthogonal direction of the front side wall of the lens holder. Therefore, the first protrusion for preventing displacement when the optical disk is not loaded collides with the cover even if an impact is applied due to dropping during transportation. Due to this collision, the first protrusion for preventing displacement when the optical disk is not loaded can limit the displacement range of the lens holder, so that deformation of the suspension wire and the like can be prevented. In particular, the first protrusion for preventing displacement when the optical disk is not loaded is provided on the bobbin for an actuator provided on the front side wall of the lens holder. Therefore, such a protrusion is provided on the left and right sides of the lens holder. Compared with the installation, the left and right widths of the entire lens holder can be narrowed, and the optical pickup can be downsized.

[0010] Further, in the optical pickup of the present invention, a laser hole is provided at substantially the center of the front side wall of the lens holder, and the pair of actuator coil bobbins are disposed on both sides of the laser hole, respectively. The first protrusions for preventing displacement when the optical disc is not loaded are preferably provided on the pair of actuator bobbins, respectively.

[0011] According to the above configuration, the pair of actuator coil bobbins are respectively disposed on both sides of the laser hole, and the first protrusion for preventing displacement when the optical disc is not loaded is A pair of actuator bobbins are provided respectively. For this reason, the right and left weight balance of the lens holder can be achieved, and a stable displacement of the lens holder can be realized.

[0012] In the optical pickup of the present invention, the first protrusion for preventing displacement when the optical disk is not loaded is on a side opposite to the laser hole of the bobbin for the actuator coil on the left and right side portions of the lens holder. Close to the side, preferably located in the position.

[0013] According to the above configuration, the first protrusion for preventing displacement when the optical disk is not loaded is provided at a position on the opposite side of the laser hole of the actuator coil bobbin and close to the left and right side portions of the lens holder. Therefore, a magnet that forms a magnetic field for the actuator coil attached to the lens holder can be arranged inside the first protrusion for preventing displacement when the optical disk is not loaded. With such a magnet arrangement, the magnet and the actuator coil The positional relationship is appropriate, and it is possible to prevent unnecessary force from being generated in the lens holder during focusing control, tracking control, and tilting control.

[0014] Further, in the optical pickup of the present invention, an optical disk is mounted at the center of the rear side wall of the lens holder for preventing displacement when not loaded with an optical disk protruding outward in the orthogonal direction of the rear side wall of the lens holder. The second protrusion for preventing displacement when the optical disk is not loaded collides with the first protrusion for preventing displacement when the optical disk is not loaded by colliding with the cover. It is preferable to limit the displacement range of the lens holder.

[0015] According to the above configuration, the second protrusion for preventing displacement when the optical disk is not loaded is provided so as to protrude outward in the orthogonal direction of the rear side wall of the lens holder. The second projection collides with the cover. Due to this collision, the second protrusion for preventing displacement when the optical disk is not loaded can limit the displacement range of the lens holder. Therefore, the first protrusion and the second protrusion for preventing displacement when the optical disk is not loaded can more reliably limit the displacement range of the lens holder on both the front side wall side and the rear side wall side of the lens holder.

[0016] Further, in the optical pickup of the present invention, a protective protrusion for preventing contact between the optical disk and the objective lens is further provided on the upper surface of the lens holder. It is preferable that the distance between the protective projections is shorter than the distance between the first projection for preventing displacement when the optical disc is not loaded and the cover.

[0017] According to the above configuration, the distance between the optical disc and the protective projection is shorter than the distance between the first projection for preventing displacement when the optical disc is not loaded and the cover. For this reason, the protective projection cannot collide with the optical disk and limit the displacement range of the lens holder! / ヽ Displacement prevention when the optical disk is not loaded even when an optical disk is not loaded and an impact is applied due to dropping during transportation. Since the first projection for impacting the cover limits the displacement range of the lens holder, it is possible to prevent the suspension wire from being deformed.

[0018] The objects, configurations, and effects of the present invention described above or other than the above will become more apparent from the explanation of the following embodiments with reference to the drawings.

Brief Description of Drawings FIG. 1 is a perspective view showing an overall configuration of an optical pickup, with a cover removed.

FIG. 2 is a perspective view showing the overall configuration of an objective lens driving device for an optical pickup according to an embodiment of the present invention.

FIG. 3 is a perspective view showing the overall configuration and cover of the objective lens driving device shown in FIG. 2.

FIG. 4 is a perspective view seen from the front side wall side of the lens holder.

FIG. 5 is a side view showing a part of the objective lens driving device shown in FIG. 2.

FIG. 6 is a perspective view of the lens holder as viewed from the rear side wall.

FIG. 7 is a cross-sectional view showing a part of the objective lens driving device shown in FIG.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of an optical pickup according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing the overall configuration of the optical pickup, with the cover removed. The optical pickup 1 is generally provided on an optical base 11 that can move along the radial direction of an optical disc (not shown), an objective lens driving device 10 mounted on the optical base 11, and the optical base 11. The laser light source 12 that emits the emitted laser light, the photodetector 13 that detects the laser light reflected by the optical disk, and the emitted laser light is guided to the optical disk, and the laser light that is reflected by the optical disk is guided to the photodetector 13 An optical system (not shown) and a cover 6 (which has been removed in FIG. 1 and shown in FIG. 3) covering the upper surface of the optical base 11 are provided.

[0022] The optical pickup 1 of the present embodiment is mounted on an optical disk device generally called an ultra slim type. In the present embodiment, for example, the optical pickup 1 is mounted on an optical disk device having a thickness of 9.5 mm. It goes without saying that the force illustrated is not limited to this thickness.

FIG. 2 is a perspective view showing the overall configuration of the objective lens driving device 10 of the optical pickup 1 according to the embodiment of the present invention. As shown in FIGS. 2 to 7, the objective lens driving device 10 includes an objective lens 22 for condensing the laser light emitted from the laser light source 12 onto the optical disc, and an upper surface 2. 11, a front side wall 212, a rear side wall 213, and left and right side portions, the objective lens 22 is held on the upper surface 211, and provided on the front side wall 212 of the lens holder 2 and the lens holder 2! / A pair of actuator coil bobbins (tracking coil bobbins 241 and 242) and a suspension wire (focusing wire 53, tracking wire 54) that is fixed to the left and right sides of the lens holder 2 and supports the lens holder 2 And a tilting wire 55) and a damper base 3 that supports the other end of each of the focusing wire 53, the tracking wire 54, and the tilting wire 55.

[0024] The lens holder 2 includes a lens holder body 21, focusing coils 231, 232, tracking coils 245 to 248, a tilting coil (not shown), wire support portions 26, 26, and connection protrusions 273. With ~ 275.

The lens holder body 21 has an upper surface 211, a front side wall 212, and a rear side wall 213 (see FIGS. 4 and 6). The front side wall 212 and the rear side wall 213 face each other in the tangential direction (Tg direction shown in FIG. 2). Further, the lens holder main body 21 is disposed on a yoke 4 described later. The lens holder main body 21 moves relative to the yoke 4 (moving in the focusing direction, which is the F direction shown in FIG. 2 or in the tracking direction, which is the Tr direction shown in FIG. 2) or tilting position so that it can tilt. Supported as possible.

The upper surface 211 of the lens body 21 is provided with two rectangular through holes 214 and 215 through which yoke pieces 431 to 432 described later pass. In addition, a laser hole 216 is formed substantially at the center in the tracking direction (Tr direction) of the front side wall 212 of the lens holder body 21 (see FIGS. 2 and 4).

[0027] The objective lens 22 is fixed to the center of the upper surface 211 of the lens holder body 21, and converges the laser light emitted from the laser light source 12 on the recording surface of an optical disc (not shown) to record the optical disk. The laser beam reflected by the surface is passed.

Further, a pair of protective projections 28 for preventing contact with the objective lens are provided around the objective lens 22. The protective projection 28 prevents contact between the recording surface of the optical disk and the objective lens 22 when the optical disk is loaded, and prevents damage to the surface of the objective lens 22. [0029] The focusing coil is composed of two rectangular focusing coils 231 and 232, and is attached to the lens holder body 21 (see FIGS. 4 and 6).

The focusing coil 231 is arranged in a magnetic field formed between the magnet 441 and the yoke piece 431 and between the magnet 444 and the yoke piece 431. On the other hand, the focusing coin 232 is arranged in a magnetic field formed between the magnet 442 and the yoke piece 432 and between the magnet 443 and the yoke piece 432.

[0031] Lead ends of the focusing coils 231 and 232 are wound around the connection protrusion 273 and electrically connected to the focusing wire 53 (see FIG. 2).

[0032] The tracking coil is composed of four tracking coils 245 to 248. The tracking coils 245 to 248 are respectively wound around four tracking coil bobbins 241 to 244 which are bobbins for an actuator coil provided integrally with the lens holder main body 21.

[0033] Two of these tracking coil bobbins 241 to 244 are formed to stand on the front side wall 212 and the rear side wall 213 of the lens holder main body 21, respectively (see FIGS. 4 and 6). These tracking coil bobbins 241 to 244 are installed between the focusing coins 231 and 232 and the magnets 441 to 444! /

The tracking coil bobbins 241 and 242 formed on the front side wall 212 are disposed on both sides of the laser hole 216 in the tracking direction (Tr direction), respectively.

[0035] As shown in FIG. 2, the tracking coils 245 to 248 are arranged in a magnetic field formed between the magnets 441 to 444 and the yoke pieces 431 and 432! RU

The lead wire ends of the tracking coils 245 to 248 are wound around the connection protrusion 274 and electrically connected to the tracking wire 54.

The tilting coil is composed of two rectangular tilting coils (not shown) provided on the lens holder 2. The two tilting coils are arranged inside the four-force single coils 231 and 232, respectively.

[0038] The tilting coil inside the focusing coil 231 is attached to the lens holder body 21 and is in a magnetic field formed between the magnet 441 and the yoke piece 431 and between the magnet 444 and the yoke piece 431. Is arranged. Meanwhile, focusing coil 2 The tilting coil on the inner side of 32 is attached to the lens holder body 21 and is disposed in a magnetic field formed between the magnet 442 and the yoke piece 432 and between the magnet 443 and the yoke piece 432. RU

[0039] The lead wire end of the tilting coil is wound around the connection protrusion 275, and the tilting wire

55 (see Figure 2).

[0040] The wire support portion 26 is formed integrally with the lens holder main body 21 so that both side (left and right side) forces in the tracking direction (Tr direction) of the lens holder main body 21 also protrude outward. These wire support portions 26 have through holes 263 to 265 for passing through one end sides of the focusing wire 53, the tracking wire 54, and the tilting wire 55, respectively (see FIGS. 4 and 6).

[0041] By filling the through holes 263 to 265 with a damping material, one end side of the focusing wire 53, the tracking wire 54, and the tilting wire 55 is held.

[0042] The first connection protrusion 273, the second connection protrusion 274, and the third connection protrusion 275 protrude outward from both side portions (left and right side portions) in the tracking direction (Tr direction) of the lens holder body 21, respectively. Are provided separately from each other.

The damper base 3 includes a damper base body 31 and wire support portions 32 and 32. A yoke 4 is fixed to the damper base 3, and the lens horeda 2 can also move or tilt with respect to the damper base 3.

The damper base body 31 is arranged at a predetermined interval from the lens holder 2 in the tangential direction (Tg direction), and is fixed to the optical base 11.

[0045] The wire support portions 32, 32 are integrally provided on both sides of the damper base body 31 in the tracking direction (Tr direction). The wire support portion 32 includes a through hole 323 through which a focusing wire 53 (described later) is inserted, a through hole 324 through which the tracking wire 54 is passed, and a through hole 325 through which the tilting wire 55 is passed. The

Further, the wire support portion 32 supports the focusing wire 53 and the tracking wire 54 via the damping material 322, respectively. The wire support portions 32 are provided with two filling recesses 321 for filling the damping material 322 above and below each wire support portion 32. It has been.

[0047] The filling recess 321 is provided at a position spaced apart from the through holes 323, 324 in the tangential direction (Tg direction), respectively. The damping material 322 prevents the resonance of the lens holder 2 caused by the focusing wire 53 and the tracking carrier 54 when the entire lens holder 2 moves or tilts.

Furthermore, a through-hole 326 through which the tilting wire 55 is passed is formed between the filling recesses 321 provided above and below each wire support portion 32. By filling the through hole 326 with a damping material, the through hole 326 supports the tilting wire 55 via the damping material. The damping material of the through hole 326 prevents resonance of the lens holder 2 caused by the tilting wire 55.

[0049] The yoke 4 includes a bottom plate portion 41, four magnet mounting portions 421 to 424, two yoke pieces 431 and 432, four magnets 441 to 444, and an extending rod 48! / Speak. The bottom plate ridge 41 is located under the lens holder body 21 described above.

The magnets 441 and 442 are arranged so as to face the front side wall 212 of the lens holder main body 21 of the lens holder 2 described above. The magnets 441 and 442 are provided on magnet attachment portions 421 and 422 that are formed integrally with the bottom plate portion 41, respectively. On the other hand, the magnets 443 and 444 are arranged so as to face the rear side wall 213 of the lens holder main body 21 of the lens holder 2 described above. The magnets 443 and 444 are provided in magnet attachment portions 423 and 424 that are formed integrally with the bottom plate portion 41, respectively.

[0051] Magnet side surfaces 441a and 442a located on the outer side in the tracking direction (Tr direction) of magnets 441 and 442 are located inside first projections 71 and 72, which will be described later.

The yoke pieces 431 and 432 are erected on the bottom plate portion 41 so as to pass through the two rectangular through holes 214 and 215 formed in the lens holder body 21. The yoke pieces 431 and 432 are inserted into the rectangular through holes 214 and 215, respectively.

The extension 48 is formed by raising and bending the damper base 3 side of the bottom plate 41 and is fixed to the damper base 3.

[0054] As described above, the suspension wire includes the focusing wire 53 and the tracking wire. And a tilting wire 55, and the focusing wire 53, the tilting wire 55, and the tracking wire 54 are arranged in this order from the top on the side of the lens holder 2.

[0055] As described above, the focusing wire 53, the tracking wire 54, and the tilting wire 55 are respectively connected to the wire support portion 26 and the damper base 3 provided on both side portions (left and right side portions) of the lens holder body 21 of the lens holder 2. It is stretched between the wire support 32. The lens holder 2 is supported so as to be displaceable with respect to the damper base 3 by elastically deforming the stretched portion.

[0056] One end of the focusing wire 53, the tracking wire 54, and the tilting wire 55 is electrically connected to the connection protrusions 273 to 275 of the lens holder described above. On the other hand, the other ends of the focusing wire 53, the tracking wire 54 and the tilting wire 55 are electrically connected to a substrate (not shown) provided on the optical base 11.

[0057] The cover 6 covers the upper surface side of the optical base 11 in order to prevent dust from entering the optical pickup 1, and includes a cover main body 61 and an opening 62 formed in the cover main body 61. (See Figure 3).

[0058] The cover body 61 is provided so as to cover a part of the damper base 3, the yoke 4, and the focusing wire 53. The cover main body 61 is fixed to an optical base (not shown).

[0059] The opening 62 is formed in the cover main body 61. More specifically, the opening 62 is formed in a rectangular shape above the lens holder 2, and is formed so as to open along the stretched portion of the focusing wire 53. The shape of the opening 62 is such that the lens holder 2 and the focusing wire 53 other than the first protrusions 71 and 72 and the second protrusion 73, which will be described later, do not contact the cover body 61 when the lens holder 2 moves. It has become. The opening 62 has front edges 63 and 64 that collide with first projections 71 and 72 described later, and a rear edge 65 that collides with a second projection 73 described later (FIGS. 3, 5, and 7). reference).

[0060] The lens holder 2 includes first protrusions 71 and 72 and second protrusions for preventing displacement when the optical disk is not loaded. A protrusion 73 is further provided (see FIGS. 4 and 6).

The first protrusions 71 and 72 are provided integrally with the lens holder 2 so as to protrude from the tracking coil bobbins 241 and 242 outward in the orthogonal direction of the front side wall 212, that is, toward the tangential direction (Tg). (See Figure 4).

The first protrusions 71 and 72 are provided at positions close to the left and right side portions of the lens holder 2 on the opposite side of the laser holes 216 of the tracking coil bobbins 241 and 242 of the front side wall 212. That is

The first protrusions 71 and 72 are provided at positions outside the tracking coil bobbins 241 and 242 in the tracking direction (Tr direction).

[0063] The distance in the focusing direction (F direction) between the optical disc and the above-described protective projection 28 is the distance between the first projections 71 and 72 and the front edges 63 and 64 of the opening 62 of the cover 6. It is shorter than the distance in the direction (F direction).

[0064] The second protrusion 73 is located on the outer side in the orthogonal direction of the rear side wall 213 from the rear side wall 213 of the lens holder 2.

That is, it is provided integrally with the lens holder 2 so as to protrude in the tangential direction (see FIG. 6).

Next, the operation of the lens holder 2 in the objective lens driving device 10 of the optical pickup 1 having the above configuration will be described. As described above, the lens holder 2 has the focusing wire 53, the tracking wire 54, and the tracking wire 54 on the damper base 3 so as to move or tilt with respect to the yoke 4 provided with the magnets 441 to 444 and the yoke pieces 431 and 432. It is supported through a tilting wire 55 so as to be displaceable. Therefore, the lens holder 2 can be displaced by the interaction between the current supplied to the focusing coils 231 and 232, the tracking coils 245 to 248 and the tilting coil and the magnetic field formed by the magnets 441 to 444. Focusing coils 231, 232, tracking coils 245 to 248, and current supplied to the tilting coil are controlled to perform focusing control, tracking control and tilting control of the objective lens 22 held in the lens holder 2. Can do.

Next, the function and effect of this embodiment will be described.

[0067] According to the present embodiment, the first protrusions 71, 72 for preventing displacement when the optical disk is not loaded are projected from the tracking coil bobbins 241, 242 in the tangential direction (Tg). Therefore, the first protrusions 71 and 72 for preventing displacement when the optical disk is not loaded collide with the front edges 63 and 64 of the cover 6 even if an impact is applied due to dropping or the like during conveyance. Due to this collision, the first protrusions 71 and 72 for preventing displacement when the optical disk is not loaded can limit the displacement range of the lens holder 2. Therefore, the first protrusions 71 and 72 for preventing displacement when the optical disk is not loaded can prevent deformation of the focusing wire 53, the tracking wire 54, and the tilting wire 55. In particular, since the first protrusions 71 and 72 for preventing displacement when the optical disk is not loaded are provided on the tracking coil bobbins 241 and 242 provided on the front side wall 212 of the lens holder 2, such protrusions are not attached to the lens. Compared with the case where the holder 2 is provided on the left and right side portions, the left and right widths of the entire lens holder 2 can be narrowed, and the optical pickup 1 can be downsized.

Further, according to the present embodiment, the tracking coil bobbins 241 and 242 are disposed on both sides of the laser hole 216, respectively, and the first protrusions 71 and 72 for preventing displacement when the optical disk is not loaded are Since the tracking coil bobbins 241 and 242 are respectively provided, the right and left weight balance of the lens holder 2 can be balanced, and a stable displacement of the lens holder 2 can be realized.

Further, according to the present embodiment, the first protrusions 71 and 72 for preventing displacement when the optical disk is not loaded are provided outside the tracking coil bobbins 241 and 242 in the tracking direction (Tr direction). The focusing coils 231 and 232 attached to the lens holder 2, the tracking coils 245 to 248, and the magnets 441 to 444 that form a magnetic field with respect to the tilting coil can be arranged inside. Such an arrangement of the magnets 441 to 444 makes the positional relationship between the magnets 441 to 444, the focusing coils 231, 232, the tracking coils 245 to 248, and the tilting coil appropriate, and provides focusing control, tracking control, and tilting. It is possible to prevent an unnecessary force from being generated in the lens holder 2 during the control.

In addition, according to the present embodiment, the second protrusion 73 for preventing displacement when the optical disk is not loaded is provided that protrudes from the rear side wall 213 of the lens holder 2 in the tangential direction (Tg direction). Therefore, the second protrusion 73 collides with the rear edge 65 of the cover 6 also on the rear side wall 213 side of the lens holder 2. This collision limits the displacement range of the lens holder 2. be able to. Therefore, the first protrusions 71 and 72 and the second protrusion 73 for preventing displacement when the optical disk is not loaded more reliably set the displacement range of the lens holder 2 on both the front side wall 212 side and the rear side wall 213 side of the lens holder 2. Can be limited.

Hereinafter, the limitation on the displacement range of the first protrusions 71 and 72 and the second protrusion 73 will be described in more detail with reference to FIG.

If the optical disk device or the optical pickup 1 is accidentally dropped during transport of the optical disk device or the optical pickup 1, an excessive impact is applied to the objective lens driving device 10. As a result, the lens holder 2 is displaced in the direction of the arrow A, and the first protrusion 71 or the first protrusion 72 collides with the front edge 63 or the front edge 64 of the opening 62 of the cover 6. That is, the first protrusion 71 or the first protrusion 72 can limit the displacement range on the front side wall 212 side of the lens holder 2. Next, the lens holder 2 is turned back in the direction of arrow B with the front edge 63 or the front edge 64 where the first protrusion 71 or the first protrusion 72 collides as a fulcrum. Therefore, the second protrusion 73 collides with the rear edge 65 of the opening 62 of the cover 6. That is, the displacement range of the lens holder 2 on the back side wall 213 side can be limited.

In this way, the second protrusion 73, together with the first protrusions 71 and 72, can more reliably limit the displacement range of the lens holder 2. Therefore, deformation of the focusing wire 53, the tracking wire 54, and the tilting wire 55 due to excessive displacement of the lens holder 2 in the focusing direction (F direction) can be prevented.

Further, according to the present embodiment, the distance between the optical disc and the protective projection 28 is such that the first projections 71 and 72 for preventing displacement when the optical disc is not loaded and the front edge 63 of the opening 62 of the cover 6, It is shorter than the distance between 64. For this reason, when an impact is applied due to a drop or the like during transportation, even when the protective projection 28 collides with the optical disk in the optical disk non-loading state and the displacement range of the lens holder 2 cannot be limited, the displacement when the optical disk is not loaded. When the first protrusions 71 and 72 for prevention collide with the front edges 63 and 64 of the opening 62 of the cover 6, the displacement range of the lens holder 2 can be limited. Therefore, the first protrusions 71 and 72 for preventing displacement when the optical disk is not loaded can prevent deformation of the focusing wire 53, the tracking wire 54, and the tilting wire 55 even when the optical disk is not loaded.

Industrial applicability [0075] According to the present invention, the actuator coil bobbin is provided with the first protrusion for preventing displacement when the optical disk is not loaded, which protrudes outwardly in the orthogonal direction of the front side wall of the lens holder. Therefore, even if an impact is applied due to a drop during transportation, it collides with the first projection force cover for preventing displacement when the optical disk is not loaded. Due to this collision, the first protrusion for preventing displacement when the optical disk is not loaded can limit the displacement range of the lens holder, so that the suspension wire can be prevented from being deformed. In particular, the first projection for preventing displacement when the optical disc is not loaded is provided on the actuator bobbin provided on the front side wall of the lens holder. Therefore, such a projection is provided on the left and right sides of the lens holder. Compared to the case of the case, the width of the entire lens holder can be narrowed, and the optical pickup can be downsized.

[0076] This application is based on Japanese Patent Application 2005-230742 filed on August 9, 2005, and the entire disclosure of the application is filed by specifying the application number. It shall be incorporated in

Claims

The scope of the claims

[1] an optical base capable of moving along the radial direction of the optical disc;

An objective lens driving device mounted on the optical base;

A laser light source for emitting laser light provided on the optical base, a photodetector for detecting laser light reflected by the optical disc,

An optical system that guides the laser beam emitted from the laser light source to the optical disc and guides the laser beam reflected by the optical disc to the photodetector;

The objective lens driving device includes an objective lens for condensing laser light onto an optical disc, an upper surface, a front side wall, and a rear side wall. The objective lens is held on the upper surface, and a pair of actuator coil bobbins provided on the front side wall of the lens holder; One end is fixed to the left and right side portions of the lens holder, and includes a plurality of suspension wires that support the lens holder, and a damper base that supports the other end of each of the plurality of suspension wires. The bobbin is provided with a first protrusion for preventing displacement when the optical disk is not loaded, protruding outward in the orthogonal direction of the front side wall of the lens holder. Ri, the first projection of the optical disc unloading time for displacement prevention, by colliding with the cover, the optical pickup and limits the displacement range of the Renzuho holder.

[2] A laser hole is provided at substantially the center of the front side wall of the lens holder, and the pair of actuator coil bobbins are disposed on both sides of the laser hole, respectively, for preventing displacement when the optical disk is not loaded. 2. The optical pickup according to claim 1, wherein the first protrusions are respectively provided on the pair of actuator bobbins.

[3] The first protrusion for preventing displacement when the optical disk is not loaded is provided at a position on the opposite side to the laser hole of the actuator coil bobbin and close to the left and right side portions of the lens holder. The optical pickup according to claim 2.

[4] A second protrusion for preventing displacement at the time of non-loading of the optical disk that protrudes outward in the orthogonal direction of the rear side wall of the lens holder is approximately at the center of the rear side wall of the lens holder. And the second protrusion for preventing displacement when the optical disk is not loaded collides with the force bar, so that the lens holder is coupled with the first protrusion for preventing displacement when the optical disk is not loaded. 2. The optical pickup according to claim 1, wherein a displacement range of the optical pickup is limited.

A protective protrusion for preventing contact between the optical disk and the objective lens is further provided on the upper surface of the lens holder, and the distance between the optical disk and the protective protrusion is determined when the optical disk is not loaded. The optical pickup according to claim 1, wherein the distance between the first protrusion for preventing displacement and the cover is shorter than the distance.