CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation application of International Application No. PCT/JP2012/000183, with an international filing date of Jan. 13, 2012, which claims priority of Japanese Patent Application NO: 2011-031596 filed on Feb. 17, 2011, the content of which is incorporated herein by reference.

BACKGROUND

1. Technical Field

The technical field relates to an optical disc driving device for performing recording or reproduction on an optical disc.

2. Description of Related Art

Conventionally, optical disc drive devices for performing recording or reproduction of information on optical discs such as DVDs and Blu-ray Discs (BDs) are mounted on electronic equipment such as game equipment, recorders and players.

This type of optical disc drive device has an internal unit including an optical pickup unit for performing optical recording or reproduction on an optical disc, a rotation drive device for driving rotation of an optical disc, a moving mechanism for moving the optical pickup unit in radial directions of an optical disc, and the like. Also, the optical disc drive device has an electroconductive, metallic exterior casing for housing the internal unit.

In information recording/reproducing devices such as hard disks, as shown in Japanese Patent Application Publication No. 2001-291985A, conventionally, an internal unit is housed in a metallic exterior casing for purposes of dust prevention for the internal unit and shielding outward radiation noise. Also in optical disc drive devices, the internal unit is housed in a metallic exterior casing from the same reasons.

SUMMARY

In cases where the exterior casing of the optical disc driving device is made up of a plurality of components, there is a need for taking measures against radiation of noise radiated from between the plurality of components to outside.

Accordingly, the present disclosure provides to reduce noise radiated outside from between a plurality of components constituting the exterior casing of the optical disc driving device.

In one general aspect, the present disclosure describes an optical disc driving device having: a metallic exterior casing composed of a first casing and a second casing; and an internal unit to be housed in the exterior casing, the internal unit including an optical pickup unit having an optical pickup part that moves in radial directions of an optical disc to perform recording or reproduction of information signals on the optical disc, wherein at a portion, which the optical pickup part moved radially outward of the optical disc makes a closest approach to, in either one of the first casing or the second casing. opposed to the first casing, a protrusion for electrically connecting the first casing and the second casing to each other is provided.

According to the present disclosure, electrical conduction between the first casing and the second casing, which constitute the exterior casing, can be ensured enough so that release of radiation noise from between the first casing and the second casing to outside can be reduced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing an appearance of an optical disc drive device according to an embodiment;

FIG. 2 is an exploded perspective view showing a state in which the exterior casing is exploded;

FIG. 3 is a schematic plan view showing a schematic structure of an internal unit of the optical disc drive device;

FIG. 4 is a plan view showing a state in which the internal unit is housed in a first casing;

FIG. 5 is a sectional view showing part of a completed structure in which with the first casing and a second casing set up, the internal unit is housed in the exterior casing;

FIG. 6 is a perspective view showing a positional relationship between the first casing and a printed wiring substrate of a control circuit block;

FIG. 7 is a perspective view showing a state in which the printed wiring substrate is excluded in FIG. 6;

FIG. 8 is a schematic sectional view showing a structure of an interfacing connector portion in the control circuit block; and

FIG. 9 is a schematic view showing a contact state between a fringe portion of an opening of the first casing and a ground pattern of the printed wiring substrate.

DETAILED DESCRIPTION

Hereinbelow, an embodiment of the present disclosure will be described with reference to the accompanying drawings.

FIG. 1 is a perspective view showing an appearance of an optical disc drive device according to an embodiment of the disclosure. FIG. 2 is an exploded perspective view showing a state in which the exterior casing is exploded. As shown in FIGS. 1 and 2, the optical disc drive device is made up with an internal unit 2 housed in an electroconductive, metallic exterior casing 1 having a disc insertion opening 1a. The exterior casing 1 also serves a role as a shield for reducing outward release of radiation noise generated from the internal unit 2.

The exterior casing 1 is composed of a quadrilateral box-like first casing 3, and a quadrilateral lid-like second casing 4 which is put on the first casing 3 so as to cover an upper opening portion of the first casing 3 and which has a front portion 4a with the disc insertion opening 1a formed therein. The internal unit 2 can be housed in the exterior casing 1 by first doing temporary fixing, i.e. hanging of the front portion 4a of the second casing 4 to a front portion of the first casing 3, then putting a rear portion of the second casing 4 on a rear portion of the first casing 3, and subsequently screwing the rear portion of the second casing 4 to the rear portion of the first casing 3 with screws 5.

As shown in FIG. 2, fixing portions 3a each having a screw hole to which a screw 5 is tightened are provided in the upper opening portion of the first casing 3. At portions of the second casing 4 corresponding to those fixing portions 3a, through holes 4b through which the screws 5 are to be inserted are provided, respectively. The screws 5 are inserted through the holes 4b of the second casing 4, respectively, so as to be tightened to the screw holes of the fixing portions 3a of the first casing 3.

Further, as shown in FIG. 2, a plurality of fitting portions 3b each having a screw hole to which a screw is tightened to fix the internal unit 2 into the first casing 3 are formed in a bottom face of the first casing 3.

The exterior casing 1 can be made by molding a sherardized steel sheet having a thickness of 0.4 mm to 0.5 mm. In particular, the first casing 3 can be made by using, for example, thin-plate sheet metal or the like of a copper sheet, tin sheet, stainless sheet or the like having a thickness of 0.2 mm to 0.3 mm. In addition, when rust-proofing property is considered preferentially important, tin plates or stainless sheets are preferably used. In addition, with cost regarded as another important factor, tin plates are preferably used.

FIG. 3 is a schematic plan view showing a schematic structure of the internal unit of the optical disc drive device. As shown in FIG. 3, the internal unit 2 has, in a metallic unit housing 2a, a spindle motor 6 for holding a center of an optical disc and rotating the disc at high speed, a disc insertion mechanism 7 for guiding an optical disc inserted through the disc insertion opening 1a to the spindle motor 6, an optical pickup unit 8 for performing recording/reproduction of information signals on an optical disc, and a control circuit block 11 having a printed wiring substrate 10 electrically connected via a flexible wiring substrate 9 to electronic components of the optical pickup unit 8.

The disc insertion mechanism 7, under control by the control circuit block 11, introduces an optical disc inserted through the disc insertion opening 1a into the internal unit 2 and guides the optical disc to the spindle motor 6 so that the center of the optical disc is aligned with a rotating shaft of the spindle motor 6.

The optical pickup unit 8 has an optical pickup part 8a on which a semiconductor laser device and an optical lens for applying light of a specified wavelength to an optical disc rotated by the spindle motor 6 are mounted, guide shafts 8b for holding the optical pickup part 8a so that the optical pickup part 8a can be moved linearly in radial directions of the optical disc, and a tracking mechanism for moving the optical pickup part 8a in radial directions of the optical disc. The tracking mechanism has a gear part 8c provided in the optical pickup part 8a, and a rotating shaft 8d to be meshed with the gear part 8c. As the rotating shaft 8d is rotated under control by the control circuit block 11, the optical pickup part 8a is moved in a radial direction of the optical disc via the gear part 8c.

The guide shafts 8b of the optical pickup unit 8 as well as the rotating shaft 8d of the tracking mechanism are held by holding parts 2b provided in the unit housing 2a.

The control circuit block 11 is so made up that a microcomputer or other semiconductor integrated circuit element 11a and its peripheral circuits are mounted on the printed wiring substrate 10 while an interfacing connector 11b for transmission and reception of electrical signals from and to external electronic equipment (not shown) is mounted thereon. The semiconductor integrated circuit element 11a of the control circuit block 11 controls the spindle motor 6, the disc insertion mechanism 7 and the optical pickup unit 8 and moreover processes signals for information writing onto an optical disc via the optical pickup unit 8 or signals read from an optical disc. Signals are also delivered and received between the control circuit block 11 and external electronic equipment via the interfacing connector 11b.

Further, on the printed wiring substrate 10 of the control circuit block 11, a ground pattern 10a is formed so as to surround the connector 11b mounted on the printed wiring substrate 10. Whereas the printed wiring substrate 10 is made up by alternately stacking electrically conductive layers of copper foil or the like and insulating layers of epoxy resin or the like, the ground pattern 10a can be formed by cutting out part of the insulating layers of the printed wiring substrate 10 so that the conductive layers are exposed.

The ground pattern 10a, as will be described later, has through holes 10b formed therein for insertion of screws serving for electrical connection of the ground pattern 10a and the first casing 3 of the exterior casing 1 to each other as well as for mechanical fitting of the printed wiring substrate 10 to the first casing 3. Further, another ground pattern (not shown) is provided at an end portion of the printed wiring substrate 10. Also provided are through holes 10c for electrical connection of the exterior casing 1 and the unit housing 2a to each other via the another ground pattern as well as for mechanical fitting of the printed wiring substrate 10 to the unit housing 2a (see FIG. 3).

FIG. 4 is a plan view showing a state in which the internal unit is housed in the first casing. As shown in FIG. 4, the internal unit 2 is housed in the first casing 3 so that the printed wiring substrate 10 of the control circuit block 11 is positioned on the bottom side, and the internal unit 2 is fitted to the fitting portions 3b in the bottom portion of the first casing 3 with screws (not shown). It is noted that as shown in FIG. 4, the internal unit 2 is fitted to the first casing 3 in a state reversed from the state shown in FIG. 3.

FIG. 5 is a sectional view showing part of a completed structure in which with the first casing and the second casing set up, the internal unit is housed in the exterior casing.

As shown in FIGS. 4 and 5, a protrusion 3c is provided at a portion of the first casing 3 to which the optical pickup part 8a moved radially outward of the optical disc makes a closest approach, i.e., at a portion of a rear-side side wall fixed with the two screws 5. In this embodiment, the protrusion 3c is provided, specifically, at a central portion of the side wall of the first casing 3 to which the optical pickup part 8a makes a closest approach and which corresponds to an intermediate position of the two screws 5.

This protrusion 3c, which protrudes outward, comes into contact with a side wall 4c of the second casing 4 when the second casing 4 is fitted to the first casing 3. As a result, the protrusion 3c and the second casing 4 are electrically connected to each other. The protrusion 3c is formed by extruding part of the side wall of the first casing 3. Alternatively, the protrusion 3c may be formed by forming two slits parallel to part of the side wall of the first casing 3 and further bending a portion between the two slits. Furthermore, the protrusion 3c may also be formed by fitting another metallic member to the side wall of the first casing 3 by welding or brazing or the like. In addition, although FIGS. 4 and 5 show one example in which one protrusion 3c is formed, a plurality of protrusions 3c may also be formed in the side wall to which the optical pickup part 8a makes a closest approach.

Reasons that such a protrusion 3c is provided are described below. Such an optical disc drive device as shown in FIGS. 1 to 5, in which the internal unit 2 is housed in the exterior casing 1 composed of the first casing 3 and the second casing 4, has been under a demand for downsizing as electronic equipment containing the optical disc drive device gets downsized more and more. For downsizing of the optical disc drive device, such measures are implemented as reduction of clearances between the internal unit 2 and the exterior casing 1, thinning of the exterior casing 1, simplification of the assembling structure of the exterior casing 1, and the like.

However, with the optical disc drive device downsized, it would occur, in some cases, that a central portion of the side wall of the first casing 3 to which the optical pickup part 8a, when moved to an outermost peripheral portion of an optical disc, makes a closest approach, and/or an opposing central portion of the side wall 4c of the second casing 4 is flexed. That is, it might occur heretofore that an unfixed portion corresponding to an intermediate position between the two screws 5 is flexed. Moreover, such flexure might cause occurrence of a gap between the side wall of the first casing 3 and the side wall 4c of the second casing 4.

With occurrence of such a gap, an elongate hole is formed so as to extend from one screw 5 toward the other screw 5, so that electrical conduction between the first casing 3 and the second casing 4 can no longer be secured enough due to the elongate hole. Then, radiation noise becomes more likely to leak from between the side wall of the first casing 3 and the side wall 4c of the second casing 4, i.e., through the elongate hole.

Accordingly, the protrusion 3c is provided at a central portion of the rear-side side wall of the first casing 3, to which the optical pickup part 8a makes a closest approach, as shown in FIGS. 4 and 5, so that even upon the closest approach of the optical pickup part 8a, the electrical connection between the first casing 3 and the second casing 4 can be maintained. More specifically, the protrusion 3c is provided in the first casing 3 so that when the second casing 4 is fitted to the first casing 3, the protrusion 3c presses the side wall 4c of the second casing toward the outside.

According to the structure having, such a protrusion 3c as shown above, even with the optical disc drive device provided in a downsized scale, electrical conduction between the portion of the side wall of the first casing 3 to which the optical pickup part 8a makes a closest approach and the opposing portion of the side wall 4c of the second casing can be secured enough. As a result, outward release of radiation noise from between the first casing 3 and the second casing 4 can be reduced.

Preferably, as shown in FIG. 3, the optical pickup unit 8 is so placed that the optical pickup part 8a is moved toward the side wall 4c opposed to the disc insertion opening 1a in the same direction as the optical-disc insertion direction. Alternatively, the optical pickup unit 8 may also preferably be so placed that the optical pickup part 8a is moved in a direction perpendicular to the optical-disc insertion direction. As a result, leakage of radiation noise to the outside through the disc insertion opening 1a can be suppressed.

Also, the protrusion 3c may be so formed not that the protrusion 3c protrudes from a side wall of the first casing 3 so as to come into contact with the side wall 4c of the second casing 4, but that the protrusion 3c protrudes from the side wall 4c of the second casing 4 so as to come into contact with the side wall of the first casing 3.

Furthermore, instead of the protrusion 3c, a protrusion electrically connected to a back face of a top plate of the second casing 4 may be provided in an upper end face of the side wall of the first casing 3 to which the optical pickup part 8a makes a closest approach. That is, at a portion between the first casing 3 and the second casing 4 where there may arise a gap due to the closest approach of the optical pickup part 8a, a protrusion for maintaining electrical connection may be provided.

FIG. 6 is a perspective view showing a positional relationship between the first casing and the printed wiring substrate of the control circuit block. FIG. 7 is a perspective view showing a state in which the printed wiring substrate is excluded in FIG. 6. FIG. 8 is a schematic sectional view showing a structure of an interfacing connector portion in the control circuit block.

As shown in FIGS. 6, 7 and 8, at a portion of the bottom of the first casing 3 corresponding to the connector 11b mounted on the printed wiring substrate 10, an opening 3d for allowing the connector 11b to be protruded outward of the first casing 3 is provided. A flat cable 12, which is a cable for external connection to fulfill transmission and reception of signals to and from external electronic equipment (not shown), is inserted into the connector 11b protruding from the opening 3d.

Also, the opening 3d of the first casing 3 is formed at a bottom portion of a recess portion 3e recessed from outside to inside of the first casing 3. The recess portion 3e is so sized as to accommodate the connector 11b protruding from the opening 3d so that the connector 11b is prevented from extending beyond the bottom face of the first casing 3.

Further, a surface 3f which is a portion of the recess portion 3e for accommodating the connector 11b therein and along which the flat cable 12 inserted into the connector 11b extends is formed as a sloped surface sloped from the bottom portion of the recess portion 3e toward an outer surface of the first casing 3. By laying down the flat cable 12 along the sloped surface 3f so that the flat cable 12 is inserted into the connector 11b protruding from the opening 3d, the flat cable 12 can easily be electrically connected to the connector 11b. For practical implementation of this, the connector 11b has an insertion opening into which the flat cable 12 is inserted in a direction crossing with, preferably orthogonal to, the direction in which the connector 11b protrudes from the opening 3d.

According to such an interconnection structure around the connector 11b as shown above, the flat cable 12 can be provided so as to extend from the connector 11b while kept along the first casing 3, which is an electric conductor. In this case, a loop area over which a common mode current flows in the flat cable 12 can be reduced. As a result, radiation noise generated from the flat cable 12 can be reduced, so that radiation noise generated from the optical disc drive device can be reduced.

Further, since the opening 3d that allows the connector 11b to be protruded is formed at a bottom portion of the recess portion 3e recessed inward of the first casing 3, the connector 11b can be placed so as not to extend beyond the bottom face of the first casing 3.

In this embodiment, the opening 3d of the first casing 3 is formed at a bottom portion of the recess portion 3e. However, the present disclosure is not limited to this. For example, the opening 3d that allows the connector 11b of the printed wiring substrate 10 to be protruded outward may be formed in the first casing 3 without forming the recess portion 3e.

Further, the external connection cable connected to the connector 11b and laid down along the sloped surface 3f of the recess portion 3e of the first casing 3 is not limited to the flat cable 12.

As described above and as shown in FIG. 8, the printed wiring substrate 10 is screwed to the fitting portions 3b of the first casing 3 with screws 13. More specifically, the printed wiring substrate 10 is fixed to the first casing 3 in a state that the ground pattern 10a formed around the connector 11b is in electrical contact with the fringe portion of the opening 3d of the first casing 3.

FIG. 9 is a schematic view showing a contact state between the fringe portion of the opening 3d of the first casing 3 and the ground pattern 10a of the printed wiring substrate 10. As shown in FIG. 9, the ground pattern 10a of the printed wiring substrate 10 is fixed to the fitting portions 3b of the first casing 3 with the screws 13, and thereby maintained in a state of electrical contact with the bottom portion (a portion indicated by area A) of the recess portion 3e, which is a fringe portion of the opening 3d of the first casing 3.

According to such an interconnection structure around the connector 11b as shown above, the ground pattern 10a of the printed wiring substrate 10 is securely electrically connected to the exterior casing 1. Also, the ground pattern 10a of the printed wiring substrate 10 is formed so as to surround the periphery of the connector 11b, coming into electrical contact with the first casing 3. Therefore, release of radiation noise to the outside through between the connector 11b and the opening 3d can be reduced. That is, the connector 11b is protruded from the opening 3d in a state that shielding is provided between the connector 11b and the opening 3d. In addition to this, intrusion of foreign matters into the exterior casing 1 through between the connector 11b and the opening 3d can be suppressed.

As described hereinabove, according to this embodiment, in the optical disc drive device, radiation noise to the outside can be reduced. Further, by virtue of the structure in which radiation noise is structurally reduced, there can be provided an optical disc drive device showing less variations in the radiation noise reduction effect.

Although the present disclosure has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such Changes and modifications are to be understood as included within the scope of the present disclosures as defined by the appended claims unless they depart therefrom.