JP4477408B2 - Optical pickup device - Google Patents

Description

  The present invention relates to an optical pickup device.

  An optical pickup device used for recording / reproducing information on / from an optical recording medium such as a compact disc (abbreviated CD) or a digital versatile disc (abbreviated DVD) generally has a short wavelength oscillated from a semiconductor laser.・ High power single mode laser is used. One technique for reducing this laser noise is a high-frequency superposition method. A high-frequency superimposing circuit for realizing the high-frequency superimposing method is provided together with a flexible printed circuit board (abbreviated as FPC board) provided for sending electric power, electric signals, and the like to the optical pickup device.

  In the optical pickup device provided with this high frequency superimposing circuit, unnecessary radiation (high frequency noise) is generated, and it becomes a problem to suppress this high frequency noise. As a conventional technique for solving such a problem, a metal plate is attached to a pickup base of an optical pickup device, and the metal plate is directly brought into contact with a ground portion of a laser unit to prevent high-frequency noise ( For example, see Patent Document 1).

  However, in the technique disclosed in Patent Document 1, a metal plate part must be separately prepared and incorporated for reducing high-frequency noise, and there is a problem that production efficiency is lowered.

  Therefore, as a simpler method for reducing high-frequency noise, the entire pickup base made of a conductive material is used as a large-capacity ground, and the ground line formed on the FPC board is brought into contact with the pickup base to propagate the FPC board. Some of them suppress unwanted radiation.

  FIG. 11 is a diagram showing the configuration of the conventional optical pickup device 1 in a simplified manner, FIG. 12 is a plan view showing an outline of a method for fixing the FPC board 6 in the optical pickup device 1 shown in FIG. 11, and FIG. It is sectional drawing seen from the cut surface line XIII-XIII shown in FIG. FIG. 11A is a plan view of the optical pickup device 1, and FIG. 11B is a side view of the optical pickup device 1.

  A conventional optical pickup device 1 is roughly provided with a pickup base 2 and an optical unit 3 provided on the pickup base 2 and including optical components such as a semiconductor laser, a collimator lens, a rising mirror, and a light receiving element as a light source. An objective lens 4 provided in the optical unit 3 for condensing a laser beam emitted from a light source onto an optical recording medium (not shown), a high-frequency superimposing circuit 5, an FPC board 6 mounted on the pickup base 2, A pressing member 7 for pressing the FPC board 6 against the pickup base 2 and a fixing member 8 for mounting and fixing the pressing member 7 on the pickup base 2 are configured. The optical pickup device 1 is slidably supported by, for example, a device main body of an optical information recording / reproducing device by a pair of guide shaft members 9a and 9b provided in parallel.

  The pickup base 2 is made of a conductive material such as an aluminum alloy, and is used as a ground. The FPC board 6 is provided to supply power to each part of the optical pickup device 1 and send an electric signal for control and the like, and is formed by printing an electric circuit on a flexible resin film, for example.

  A ground line 10 for grounding high-frequency noise to the pickup base 2 is formed in the FPC board 6 in advance, and the ground line 10 faces the pickup base 2 at an opening 11 formed in the FPC board 6. The pickup base 2 is exposed and exposed. The ground line 10 in the opening portion 11 is formed in an o shape having a planar shape in the center. Further, the FPC board 6 is formed with an FPC fixing hole 15 which is a through hole in a portion corresponding to a central space formed in the O shape of the ground line 10.

  The pressing member 7 is a flat plate member made of metal such as stainless steel, and is provided on the FPC board 6 mounted on the pickup base 2 so as to press the FPC board 6 against the pickup base 2. Provided. A fixing hole 12 penetrating in the thickness direction of the pressing member 7 is formed at a position corresponding to the opening 11 formed in the FPC board 6 of the pressing member 7. The fixed hole 12 is formed to have a diameter substantially equal to the o-shaped central space portion of the ground line 10.

  In the conventional optical pickup device 1, the fixing member 8 includes a male screw member 13 and a female screw portion 14 formed on the pickup base 2 so as to correspond to the male screw member 13. The male screw member 13 is inserted into the fixing hole 12 formed in the pressing member 6 and the FPC fixing hole 15 formed in the FPC board 6, and is screwed into the female screw portion 14 formed in the pickup base 2 and tightened. The ground line 10 is configured to be biased and contacted with the pickup base 2 together with the pressing member 7 and the FPC board 6 to ground the high frequency noise to the pickup base 2.

  However, when the male screw member 13 is simply fixed by tightening, the joining force is lowered and loosened due to a change with time and a vibration load caused by repeated movement of the optical pickup device 1, and the ground line 10 and the pickup base 2 A gap is generated between the two. Such a gap is generated in the same manner even when the male screw member 13 or the male screw member 13 that has been subjected to the loosening prevention process is prevented from being loosened by an adhesive. By generating such a gap, the contact force between the ground line 10 of the flexible substrate 6 and the pickup base 2 is weakened, so that the ground effect of the entire pickup base 2 is reduced and high-frequency noise is increased. There is a problem.

JP 2000-67454 A

  An object of the present invention is to provide an optical pickup device capable of suppressing high-frequency noise without reducing the contact force between a ground line and a pickup base regardless of time and repeated use.

The present invention relates to an optical pickup device that records information on an optical recording medium by light and / or reproduces information from the optical recording medium.
A pickup base made of a conductive material;
A flexible printed circuit board opening facing the pickup base is mounted on the pickup base is Ru is formed, and the flexible printed circuit board ground line exposed at the opening provided with the high frequency superposition circuit is formed,
A pressing member for pressing the flexible printed circuit board against the pickup base ,
A protrusion made of a material having elasticity and protruding toward the flexible printed circuit board is formed at a position corresponding to the opening formed in the flexible printed circuit board, and the ground line is formed with respect to the pickup base by the elastic force of the protrusion. A presser member that urges and contacts ,
A fixing member for mounting fixing the pressing member to the pickup base is an optical pickup apparatus according to claim including that.

Or the invention, the pressing member is characterized in that the notch is formed in the projecting portion.

In the present invention, the presser member is
Made of metal,
It faces the pressing member and contacts a ground line exposed at an opening formed in the flexible printed circuit board.
Further, the present invention is characterized in that the metal that is a material of the pressing member is stainless steel.

  According to the present invention, the fixing member includes a male screw member and a female screw portion formed on the pickup base.

  According to the present invention, the connection between the ground line of the FPC board and the pickup base is not loosened even with time and repeated use, so that the optical pickup device can reliably suppress unnecessary radiation (high-frequency noise) over a long period of time. Is realized.

  FIG. 1 is a plan view showing a simplified configuration of a fixed portion of an FPC board 20 in an optical pickup device according to a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II shown in FIG. FIG. Since the optical pickup device of the present invention is configured in the same manner as the optical pickup device 1 shown in FIG. 11 except for the fixing portion of the FPC board 20, the optical pickup device in the first embodiment and the following embodiments is used. The drawings and description showing the overall configuration of the above are omitted.

  The fixed portion of the FPC board 20 of the optical pickup device in the present embodiment includes a pickup base 21 made of a conductive material, an FPC board 20 mounted on the pickup base 21, and the FPC board 20 with respect to the pickup base. And a pressing member 22 that presses and holds, and a fixing member 23 that attaches and fixes the pressing member 22 to the pickup base.

  Since the FPC board 20 is configured in the same manner as the FPC board 6 provided in the optical pickup device 1 described above, the description thereof is omitted. The pickup base 21 is made of a conductive material, and the material is not particularly limited. For example, an aluminum alloy, a magnesium alloy, a copper alloy, or the like is used. The pickup base 21 made of a conductive material acts so that the ground line 25 of the FPC board 20 exposed at the opening 24 formed in the FPC board 20 contacts the pickup base 21 and grounds high-frequency noise. To do.

  The holding member 22 is made of a material having elasticity, for example, stainless steel, iron alloy, copper alloy, etc. Among them, stainless steel having an appropriate spring property and excellent corrosion resistance is preferably used as the material. In the holding member 22 of the present embodiment, a protrusion 26 protruding toward the FPC board 20 is formed at a position corresponding to the opening 24 formed in the FPC board 21 and exposing the ground line 25. It is formed. Formation of the protrusion 26 in the pressing member 22 can be realized by, for example, pressing.

  The holding member 22 is provided further above the FPC board 20 mounted on the pickup base 21 and acts to hold the FPC board 20 against the pickup base 21. Since the pressing member 22 has a stronger elasticity, that is, a spring property in the protruding portion 26 when the protruding portion 26 is formed, the FPC board 20 and the ground line 25 formed on the FPC board 20 are opened. 24, the force of pressing against the pickup base 21 can be improved.

  The fixing member 23 includes a male screw member 27 and a female screw portion 28 formed on the pickup base 21. The male screw member 27 is inserted into the fixing hole 29 and the FPC fixing hole 30 respectively formed in the holding member 22 and the FPC board 20 so as to correspond to the opening 24, and is screwed into the female screw portion 28 and tightened. The line 25 is urged and brought into contact with the pickup base 21 by the elastic force of the protruding portion 26 formed on the pressing member 22. The elastic force of the protrusion 26 formed on the pressing member 22 not only urges the ground line 25 against the pickup base 21 but also allows the repulsive force to act on the screw head 27 a of the male screw member 27. Therefore, the effect of preventing the loosening of the male screw member 27 can be achieved.

  In this way, the protrusion 26 is formed on the presser member 22, and the ground line 25 is sufficiently and reliably grounded to the pickup base 21, and the fixing member can be used over time and repeatedly. Thus, an optical pickup device can be realized in which high-frequency noise can be reliably suppressed over a long period of time without causing a gap between the ground line 25 and the pickup base 21 due to loosening of the ground 23.

  FIG. 3 is a plan view showing a simplified configuration of the fixing portion of the FPC board 20 in the optical pickup device according to the second embodiment of the present invention, and FIG. 4 is viewed from the section line IV-IV shown in FIG. FIG. The configuration of the fixed portion of the FPC board 20 of this embodiment is similar to the corresponding portion of the first embodiment, and the corresponding portions are denoted by the same reference numerals and description thereof is omitted.

  The optical pickup device according to the present embodiment is characterized in that a notch 33 is formed in the protrusion 32 formed in the pressing member 31. By forming the notch 33 in the protrusion 32, the rigidity of the protrusion 32 is relaxed and the deformability is improved, so that the elastic force acts more effectively. Accordingly, the protrusion 32 of the pressing member 31 does not excessively press the FPC board 20 and the ground line 25 against the pickup base 21, so there is no possibility of damaging the FPC board 20 and the ground line 25. It becomes possible to suppress high frequency noise smoothly.

  FIG. 5 is a plan view showing a simplified configuration of the fixing portion of the FPC board 35 in the optical pickup device according to the third embodiment of the present invention, and FIG. 6 is viewed from the section line VI-VI shown in FIG. FIG. The configuration of the fixed portion of the FPC board 35 of the present embodiment is similar to the corresponding portion of the second embodiment, and corresponding portions are denoted by the same reference numerals and description thereof is omitted.

  The FPC board 35 of this embodiment corresponds to the opening 24 formed facing the pickup base 21, and the second opening 36 is also formed on the side facing the pressing member 31. Accordingly, the portion of the ground line 25 formed in an o-shape is configured so as to expose both the pickup base 21 and the pressing member 31 in the opening 24 and the second opening 36. Thus, when the ground line 25 is pressed against the pickup base 21 by the fixing member 23 via the pressing member 31, the pressing member 31 made of conductive stainless steel also comes into contact with the ground line 25, and the pressing member Since it can be grounded to the pickup base 21 through 31 and the male screw member 27, high frequency noise can be reliably suppressed.

  FIG. 7 is a plan view showing a simplified configuration of the fixing portion of the FPC board 20 in the optical pickup device according to the fourth embodiment of the present invention, and FIG. 8 is viewed from the section line VIII-VIII shown in FIG. FIG. The configuration of the fixed portion of the FPC board 20 of the present embodiment is similar to the corresponding portion of the first embodiment, and corresponding portions are denoted by the same reference numerals and description thereof is omitted.

  It should be noted in the present embodiment that the pickup base 41 faces the FPC board 20 in correspondence with the ground line 25 exposed at the opening 24 formed in the FPC board 20 facing the pickup base 41. A protruding portion 42 is formed, and the FPC board 20 is mounted on the pickup base 41 such that the protruding portion 42 contacts the ground line 25. Thus, when the male screw member 27, which is the fixing member 23, is fastened to the female screw portion 28 of the pickup base 41, the protruding portion 42 of the pickup base 41 is used in place of the protruding portion 26 of the pressing member 22 in the first embodiment. However, since the FPC board 20 sandwiched between the pressing member 40 and the pickup base 41 can be pressed locally and strongly, the ground line 25 surely grounds to the pickup base 41 and repeats over time and repeatedly. In use, the connection between the ground line 25 and the pickup base 41 is not loosened.

  FIG. 9 is a plan view showing a simplified configuration of the fixing portion of the FPC board 45 in the optical pickup device according to the fifth embodiment of the present invention, and FIG. 10 is viewed from the section line XX shown in FIG. FIG.

  The optical pickup device of the present embodiment is characterized by the fixing member 50. The fixing member 50 includes a presser member 48 and a pickup base 47. On the pickup base 47, an engagement protrusion 52 is formed so as to protrude from the engagement side surface 51 on one side surface 51 (hereinafter referred to as the engagement side surface 51 for convenience) orthogonal to the surface on which the FPC board 45 is mounted. .

  The holding member 48 is made of stainless steel as in the optical pickup device of the above-described embodiment, and the shape viewed from the cutting plane line XX is formed in a substantially L shape. The pressing member 48 is provided so that one side 48 a of a substantially L shape comes into contact with the engaging side surface 51 and the other side 48 b presses the FPC board 45 mounted on the pickup base 47. A through hole is formed in a rectangular shape on one side 48 a of the pressing member 48, and this through hole constitutes the engagement recess 53. The pressing member 48 is mounted and fixed to the pickup base 47 such that the engagement recess 53 engages with the engagement protrusion 52 formed on the pickup base 47.

  On the other side 48 b of the pressing member 48, a punching hole 54 having a substantially U-shaped planar shape is formed at a position corresponding to the opening 24 formed in the FPC board 45. The tongue-like piece 49 formed on the other side 48a of the presser member 48 as the remaining portion of the substantially U-shaped punching hole 54 is attached to the FPC board 45 in a state of being mounted on the pickup base 47 when punching the punching hole 54. It is pressed so that it bends slightly. This bending press process reinforces the elastic force of the tongue-like piece 49.

  When the engaging recess 53 formed on one side 48 a of the pressing member 48 is engaged with the engaging protrusion 52 of the pickup base 47 and the pressing member 48 is mounted on the pickup base 47, the other side 48 b of the pressing member 48. The tongue-like piece 49 formed in the step presses and fixes the FPC board 45 to the pickup base 47 by its elastic force. Thus, in the optical pickup device of the present embodiment, the FPC board 45 can be fixed by the pressing member 48 and the pickup base 47 without using a screw member. Further, since the tongue-like piece 49 is formed at a position corresponding to the opening 24 where the ground line 46 is exposed in the FPC board 45, the ground line 46 is securely grounded to the pickup base 47 by its elastic force, Looseness can be prevented.

1 is a plan view showing a simplified configuration of a fixed portion of an FPC board 20 in an optical pickup device according to a first embodiment of the present invention. It is sectional drawing seen from the cut surface line II-II shown in FIG. It is a top view which simplifies and shows the structure of the fixing | fixed part of the FPC board 20 in the optical pick-up apparatus which is the 2nd Embodiment of this invention. It is sectional drawing seen from the cut surface line IV-IV shown in FIG. It is a top view which simplifies and shows the structure of the fixing | fixed part of FPC board | substrate 35 in the optical pick-up apparatus which is the 3rd Embodiment of this invention. It is sectional drawing seen from the cut surface line VI-VI shown in FIG. It is a top view which simplifies and shows the structure of the fixing | fixed part of the FPC board 20 in the optical pick-up apparatus which is the 4th Embodiment of this invention. It is sectional drawing seen from the cut surface line VIII-VIII shown in FIG. It is a top view which simplifies and shows the structure of the fixing | fixed part of the FPC board 45 in the optical pick-up apparatus which is 5th Embodiment of this invention. It is sectional drawing seen from the cut surface line XX shown in FIG. It is a figure which simplifies and shows the structure of the conventional optical pick-up apparatus 1, It is a top view which shows the outline of the fixing method of FPC board | substrate 6 in the optical pick-up apparatus 1 shown in FIG. It is sectional drawing seen from the cut surface line XIII-XIII shown in FIG.

Explanation of symbols

20, 35, 45 FPC board 21, 47 Pickup base 22, 31, 40, 48 Holding member 23, 50 Fixing member 24, 36 Opening
25, 46 Ground line 26, 32 Protruding part 27 Male thread member 28 Female thread part 33 Notch part 42 Protruding part 49 Tongue piece 52 Engaging protrusion 53 Engaging recess

Claims (5)

In an optical pickup device for recording information on an optical recording medium by light and / or reproducing information from the optical recording medium,
A pickup base made of a conductive material;
A flexible printed circuit board opening facing the pickup base is mounted on the pickup base is Ru is formed, and the flexible printed circuit board ground line exposed at the opening provided with the high frequency superposition circuit is formed,
A pressing member for pressing the flexible printed circuit board against the pickup base ,
A protrusion made of a material having elasticity and protruding toward the flexible printed circuit board is formed at a position corresponding to the opening formed in the flexible printed circuit board, and the ground line is formed with respect to the pickup base by the elastic force of the protrusion. A presser member that urges and contacts ,
The optical pickup apparatus according to claim including that a fixing member for mounting fixing the pressing member to the pickup base. The presser member is
The optical pickup apparatus of claim 1, wherein the notch is formed in the projecting portion. The holding member is
Made of metal,
3. The optical pickup device according to claim 1, wherein the optical pickup device faces the pressing member and contacts a ground line exposed at an opening formed in the flexible printed circuit board. The optical pickup device according to claim 3 , wherein the metal that is a material of the pressing member is stainless steel. The fixing member is
Male screw member and the optical pickup device according to any one of claims 1-4, characterized in that it comprises a female thread portion formed on the pickup base.

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