JP4045809B2 - Optical disk device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical disk device, and more particularly to an optical disk device such as an external CD-ROM device used by being connected to a computer main body.
[0002]
[Prior art]
In the optical disk apparatus incorporated in the computer main body, countermeasures against electromagnetic interference are taken by the box of the computer main body. However, in an external type disk device used in connection with the computer main body, it is necessary to take measures against electromagnetic interference by the optical disk device itself.
[0003]
In the conventional external type optical disc apparatus, the countermeasure against electromagnetic interference has been made by forming a metal plating layer on the inner surfaces of the housing and the lid which are synthetic resin molded products.
[0004]
[Problems to be solved by the invention]
Forming the metal plating layer on the inner surfaces of the housing and the lid is costly and increases the manufacturing cost of the optical disk device. Also, the effect of shielding electromagnetic waves was low.
[0005]
SUMMARY An advantage of some aspects of the invention is that it provides an optical disc apparatus that solves the above-described problems.
[0006]
[Means for Solving the Problems]
The invention of claim 1 is a structure in which a mechanism unit having a moving optical head is incorporated in a housing, and is used in connection with a computer.
While the mechanism unit is covered with a shield case made of metal plate ,
The optical head is configured to be fitted to a guide shaft and move along the guide shaft, and to have a permanent magnet piece that is magnetically attracted to the guide shaft.
The shield case made of a metal plate is configured to have an opening window in a portion facing the portion where the permanent magnet piece moves .
[0007]
By covering with a shield case made of a metal plate, it is not necessary to form a costly metal plating layer, and the effect of shielding electromagnetic waves is enhanced.
[0009]
The opening window increases the distance between the permanent magnet piece and the portion of the shield case made of metal plate that is closest to the permanent magnet piece, thereby reducing the attractive force of the permanent magnet piece to the shield case made of metal plate. Thereby, the smoothness of the movement of the optical head is guaranteed.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
1A and 1B show an external type optical disc apparatus 1 according to an embodiment of the present invention. FIG. 1A shows a state during a reading operation, and FIG. 1B shows a state in which the lid is opened. X1-X2 is the width direction, Y1-Y2 is the depth direction, and Z1-Z2 is the height direction.
[0011]
The optical disc apparatus 1 includes a housing 2, a lid 3 that can be opened and closed on the upper surface side of the housing 2, and a mechanism unit 4 incorporated in the housing 2. Both the housing 2 and the lid 3 are synthetic resin molded parts.
[0012]
As shown in FIG. 4, the mechanism unit 4 has a structure in which a mechanism unit body 10 is fixed inside a rectangular frame 11 that is a synthetic resin molded part, and the frame 11 is fixed on a printed circuit board 12. Reference numeral 13 denotes a tin plate box-shaped shield cover member, which covers the unit main body 10 and the frame body 11.
[0013]
The mechanism unit main body 10 has a configuration in which a turntable 20 and an optical head 21 are provided on a rectangular metal plate member 22. The turntable 20 is fixed to the spindle of the motor 23, and the motor 23 is fixed to the metal plate member 22. On the metal plate member 22, a main guide rail 24 and a sub guide rail 25 for the optical head 21 are arranged in parallel with their both ends fixed. The main guide rail 24 and the sub guide rail 25 are both iron round bars. The optical head 21 has an objective lens 26 on the upper surface, a semiconductor laser, a focus drive unit, and a tracking drive unit (both not shown) inside, and a guide hole 21a on the X2 side is fitted into the main guide rail 24, and X1 The guide groove 21b on the side is fitted to the sub guide rail 25 and supported so as to be movable in the Y1-Y2 direction. A permanent magnet piece 27 for preventing rattling between the guide groove 21b and the sub guide rail 25 is incorporated at a position directly above the sub guide rail 25 on the X1 side. A rack 28 is fixed to the side of the optical head 21 where the guide hole 21a is formed. Further, a feed motor 29, a worm gear mechanism 30, and a rack and pinion mechanism 31 are provided on the lower surface of the metal plate member 22.
[0014]
When the feed motor 29 is driven, the optical head 21 is moved to Y1-Y2 while being supported by the main guide rail 24 and the sub guide rail 25 via the worm gear mechanism 30 and the rack and pinion mechanism 31. The permanent magnet piece 27 is magnetically attracted to the sub guide rail 25, a magnetic force F in the Z2 direction is generated on the X1 side of the optical head 21, and the guide groove 21b is moved in the Z2 direction with respect to the sub guide rail 25. Of the inner surface of the groove 21b, the surface 21c on the Z1 side always continues to contact the sub guide rail 25. Therefore, the optical head 21 is stably moved without being affected by the play between the guide groove 21b and the sub guide rail 25, and maintains a constant posture.
[0015]
The box-shaped shield cover member 13 made of a tin plate has a top plate portion 40 and surrounding side plate portions 41, and the leg portions 42 of the side plate portions 41 are fitted into the slits 12a of the printed circuit board 12 and soldered. In addition, the opening 43 of the side plate 41 is engaged with and attached to the protrusion 11 a of the frame 11. The leg portion 42 is electrically connected to the ground pattern of the printed circuit board 12, and the shield cover member 13 is at ground potential.
[0016]
The top plate portion 40 covers the mechanism unit main body 10. Here, in order to reduce the thickness of the mechanism unit 4 and the optical disc apparatus 1, the top plate portion 40 is disposed as low as possible. The top plate portion 40 is formed with an opening window 44 for exposing the range in which the optical head 21 moves, the turntable 20 to be exposed, and an area in which the permanent magnet piece 27 moves. . The opening window 45 has an elongated shape in Y1-Y2.
[0017]
As shown in FIG. 2, a metal plate member 50 is fixed to the upper surface of the bottom plate portion 2 a of the housing 2. The mechanism unit main body 10 to which the shield cover member 13 is attached has the lower surface of the printed circuit board 12 fixed to the metal plate member 50. The metal plate member 50 is at ground potential.
[0018]
Note that an optical disk housing portion 60 is formed on the upper surface of the housing 2. The turntable 20 protrudes from the optical disc housing 60. The lid 3 covers the optical disc housing 60.
[0019]
When the operator opens the lid 3 as shown in FIG. 1B, mounts the optical disk 70 on the turntable 20, closes the lid 3, and presses the read button, the motor 23, the semiconductor laser, and the feed motor 29 is driven, the optical disk 70 is rotated, the optical head 21 is moved, the laser beam relatively scans the optical disk 70, and information is read. The optical disk 70 is a CD-ROM, CD-R, CD-RW, DVD, or the like.
[0020]
When the optical disc apparatus 1 is operating, electromagnetic waves are generated from the mechanism unit main body 10, particularly from the semiconductor laser portion in the optical head 21 and from the printed circuit board 12. The generated electromagnetic wave is shielded by the shield lid member 13 and the metal plate member 50, so that the electromagnetic wave is effectively limited from being radiated to the outside of the optical disc apparatus 1.
[0021]
Here, in the configuration in which the opening window 45 is not formed, since the top plate portion 40 is close to the permanent magnet piece 27, the permanent magnet piece 27 that should be attracted to the sub guide rail 25 originally. May also be attracted to the top plate portion 40, and in some cases, the original function of the permanent magnet piece 27 may be impaired, and stabilization of the movement of the optical head 21 may be impaired.
[0022]
Therefore, in the present embodiment, the opening window 45 is formed. By forming the opening window 45, the distance between the top plate portion 40 and the permanent magnet piece 27 is the distance between the portion of the top plate portion 40 facing the opening window 45 and the permanent magnet piece 27. It becomes d1 and becomes longer than the distance d2 between the top plate portion 40 and the permanent magnet piece 27 when the opening window 45 is not formed. Therefore, the permanent magnet piece 27 becomes difficult to be attracted to the top plate portion 40, the interference between the permanent magnet piece 27 and the shield cover member 13 is eliminated, and the permanent magnet piece 27 is exclusively attracted to the sub guide rail 25. The optical head 21 moves stably.
[0023]
【The invention's effect】
As described above, the invention of claim 1 is a structure in which a mechanism unit having a moving optical head is incorporated in a housing. In a disk device used by being connected to a computer, the mechanism unit is made of a metal plate. Therefore, it is not necessary to form a costly metal plating layer, and the effect of shielding electromagnetic waves can be enhanced compared to the conventional case.
[0024]
Further, the optical science head is configured to move along the guide shaft is fitted to the guide shaft, and has a structure in which a permanent magnet pieces which are sucked the guide shaft and magnetically, the Since the shield case made of a metal plate has an opening window in a portion facing the portion where the permanent magnet piece moves, the permanent magnet piece and the metal plate made by forming the opening window. The distance between the shield case and the portion closest to the permanent magnet piece becomes longer, and the attractive force of the permanent magnet piece to the shield case made of metal plate is reduced, which makes the movement of the optical head smoother. Can be guaranteed. That is, it is possible to realize an optical disk apparatus that is less expensive to manufacture than the conventional one, has a high effect of shielding electromagnetic waves, and does not impair the smooth movement of the optical head.
[Brief description of the drawings]
FIG. 1 is a diagram showing an optical disc apparatus according to an embodiment of the present invention.
FIG. 2 is a sectional view taken along line II-II in FIG.
FIG. 3 is a plan view of the mechanism unit in FIG. 2;
4 is a perspective view showing the mechanism unit of FIG. 3 with its shield lid member removed. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 External type optical disk apparatus 2 Housing 3 Cover body 4 Mechanism unit 10 Mechanism unit main body 12 Printed circuit board 13 Shield cover member 20 Turntable 21 Optical head 21a Guide hole 21b Guide groove 24 Main guide rail 25 Sub guide rail 27 Permanent magnet piece 40 Top plate part 45 Elongated opening window

Claims (1)

In the optical disk apparatus used in connection with a computer, a mechanism unit having a moving optical head is incorporated in the housing.
While the mechanism unit is covered with a shield case made of metal plate ,
The optical head is configured to be fitted to a guide shaft and move along the guide shaft, and to have a permanent magnet piece that is magnetically attracted to the guide shaft.
The optical disc apparatus characterized in that the shield case made of a metal plate has an opening window in a portion facing the portion where the permanent magnet piece moves .

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