JP2005011867A - Circuit board and optical pickup device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit board equipped with a metal reinforcing plate which is excellent in strength and never causes a trouble, such as a short circuit, to the wiring pattern of an FPC board; and to provide an optical pickup device equipped with the above circuit board. <P>SOLUTION: The circuit board is equipped with the FPC board 24 where the cut holes 23 of a wiring pattern 22 are bored, and one or more metal plates 26 provided on regions including the wiring pattern cut hole forming region and electronic part mounting region of the FPC board 24. A hole 27 larger than the cut hole 23 of the wiring pattern 22 is bored in the metal plate 26 at a position corresponding to the cut hole 23, or an insulator larger in area than the cut hole 23 of the wiring pattern 22 is provided, whereby the above problem can be solved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a circuit board in which a flexible printed circuit board (flexible printed circuit board; hereinafter referred to as an FPC board) is reinforced with a metal plate, and an optical pickup device including the circuit board.
[0002]
[Prior art]
An optical pickup device used for recording / reproduction of an optical recording disk such as a CD or a DVD has a metal frame such as aluminum, an optical element housed in the frame, and an objective lens driving device. Such an optical pickup device is equipped with an FPC board which is a circuit board for controlling the objective lens driving device and optical elements.
[0003]
An FPC board is usually a circuit board in which a copper wiring pattern is formed on a resin film such as polyimide and a cover film is further provided thereon, and an electronic component is soldered to a soldering land formed on the FPC board. It is attached and used. In order to increase the strength of the mounting surface of the electronic component to facilitate mounting of the electronic component on this FPC board, in order to prevent the mounted electronic component from peeling off due to bending of the FPC board or the like, or A reinforcing plate for attaching and detaching the FPC board to and from the connector stably is attached.
[0004]
As such a reinforcing plate, a glass cloth substrate (ANSI / NEMA grade: FR-4), a laminated substrate of glass cloth and glass nonwoven fabric (ANSI / NEMA grade: CEM-3), a phenol resin substrate (ANSI). / NEMA grade: FR-1) and the like are used. Moreover, although it is not for optical pick-up apparatuses, the example which used the metal plate as a reinforcement board is also reported (for example, refer patent document 1, 2).
[0005]
[Patent Document 1]
JP 2003-21863 A [Patent Document 2]
Japanese Patent Laid-Open No. 2001-223446
[Problems to be solved by the invention]
However, since glass fiber is contained in the glass cloth base material or the laminated base material of the glass cloth and the glass nonwoven fabric described above, when they are used for the reinforcing plate, the glass fiber is collected from the end face of the reinforcing plate. There was a problem of dropping out. In particular, in the optical pickup device, there is a problem that dust easily adheres to the optical component, and the attached dust is difficult to remove by washing, which may deteriorate the optical characteristics. Further, these base materials containing glass fibers have a problem of high cost.
[0007]
In addition, the phenol resin base material is low in cost, but has a drawback that the strength is insufficient, and there is a problem that the phenol resin base material cannot be used when force is applied by inserting and removing the connector.
[0008]
On the other hand, in the FPC board, since the electric solder plating is performed on the soldering lands on which the electronic components are mounted, the wiring pattern is usually designed so that all the soldering lands are connected. However, for example, as shown in FIG. 8A, finally, only the wiring pattern 81 through which the electric signal passes is left, and a cut hole 83 is formed in the unnecessary wiring pattern 82 to block conduction of the electric signal. Such drilling causes wear of the tip of the drilling member. For example, as shown in FIG. 8B, a sag 90 is generated in the copper foil 87 of the FPC board 85 at the time of drilling. In some cases, there is a problem that the adhesive 89 provided between the metal plates 84 exceeds or breaks through and comes into contact with the metal plate 84 as a reinforcing plate to cause a short circuit.
[0009]
The present invention has been made to solve the above problems, and an object of the present invention is to provide a circuit board that is excellent in strength and has no problems such as a short circuit, and an optical pickup device including the circuit board. .
[0010]
[Means for Solving the Problems]
A circuit board according to a first aspect of the present invention for solving the above problems includes a flexible printed circuit board in which a cut hole of a wiring pattern is formed, a wiring pattern cut hole formation region of the flexible printed circuit board, and an electronic component mounting A circuit board having one or more metal plates bonded to a region including a region, wherein the metal plate at a position corresponding to the cut hole of the wiring pattern has a hole larger than the wiring pattern cut hole. It is formed.
[0011]
According to the present invention, since the hole larger than the cut hole for cutting off the wiring pattern is formed in the metal plate at the position corresponding to the cut hole of the wiring pattern, even if the copper foil of the wiring pattern sags, the wiring There is no short circuit between the pattern and the metal plate. Further, since a metal plate is used as the reinforcing plate, the strength is high and there is no problem of dust made of glass fiber.
[0012]
A circuit board according to a second aspect of the present invention for solving the above problems includes a flexible printed circuit board in which a cut hole of a wiring pattern is formed, a wiring pattern cut hole formation region of the flexible printed circuit board, and an electronic component mounting A circuit board having one or more metal plates bonded to a region including a region, wherein the metal plate surface at a position corresponding to the wiring pattern cut hole has a larger area than the wiring pattern cut hole. An insulator is provided.
[0013]
According to the present invention, since the insulator having a larger area than the cut hole of the wiring pattern is provided on the metal plate at the position corresponding to the cut hole of the wiring pattern, even if the copper foil of the wiring pattern is sagged, it intervenes. The wiring pattern and the metal plate are blocked by the insulator so that no short circuit occurs. Further, since a metal plate is used as the reinforcing plate, the strength is high and there is no problem of dust made of glass fiber.
[0014]
In the circuit boards according to the first and second aspects, a ground terminal of the flexible printed circuit board and the metal plate are electrically connected.
[0015]
According to this invention, noise countermeasures for the FPC board can be taken by positively connecting the ground terminal of the flexible printed circuit board to the metal plate.
[0016]
In the circuit boards according to the first and second aspects, the metal plate is a copper-clad laminated metal plate in which a wiring pattern is formed on a metal substrate via an insulating film, and the wiring of the copper-clad laminated metal plate The pattern is conductive with the wiring pattern of the flexible printed circuit board to form a circuit pattern.
[0017]
According to this invention, the reinforcing plate is a copper-clad laminated metal plate, and by connecting the copper layer of the metal plate and the wiring pattern of the FPC board, the wiring board wiring flexibility can be greatly improved. And high-density wiring can be realized.
[0018]
In order to solve the above problems, an optical pickup device of the present invention includes the above-described circuit board of the present invention.
[0019]
According to the present invention, it is possible to obtain an optical pickup device having a stable quality, and dust or the like derived from the reinforcing plate does not adhere electrostatically to an optical element such as a lens, so that optical characteristics are not hindered.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a circuit board of the present invention and an optical pickup device including the circuit board will be described with reference to the drawings.
[0021]
(Optical pickup device)
FIG. 1 is a schematic configuration diagram showing an optical system of an optical pickup device of the present invention, and FIG. 2 is a configuration diagram showing an example of the optical pickup device of the present invention. 2A is a plan view, FIG. 2B is a front view, and FIG. 2C is a right side view.
[0022]
An optical pickup device 1 according to the present invention performs information recording and information reproduction on an optical recording disk 5 such as a CD or a DVD, and includes a frame 2, an objective lens driving device 4 and an optical element 3 accommodated in the frame 2. And an FPC board 6 which is a circuit board for controlling the objective lens driving device 4 and the optical element 3.
[0023]
The objective lens driving device 4 drives the objective lens 7 for converging the light emitted from the laser diode 16 as a laser light source to the optical recording disk 5 in the focusing direction (focusing error correction direction) and the tracking direction (tracking error correction direction). This is a device for controlling, and includes a tracking drive coil and a focusing drive coil, and further includes a tracking drive magnet and a focusing drive magnet.
[0024]
The optical element 3 includes a laser diode 16, a beam splitter 17, a lens 18, a reflection mirror 19, and the like, and a photodetector (not shown) that receives the return light reflected by the optical recording disk 5 is also included in the optical element. included. Such an optical element is positioned and fixed to the frame 2 with high accuracy by, for example, an adhesive.
[0025]
The frame 2 is an aluminum die cast product extending in the horizontal direction with substantially the same thickness as the objective lens driving device 4. The inner side is roughly divided into an attachment region for accommodating the optical element 3 described above and an attachment region for accommodating the objective lens driving device 4. A main shaft guide hole 11 made of a round hole and a counter shaft guide groove 12 protruding in a U-shape are formed at both ends of the frame 2. The optical pickup device 1 has a radial direction of the optical recording disk 5 along a main shaft and a sub shaft (not shown) on the main body side of the recording / reproducing apparatus that are passed through each of the main shaft guide hole 11 and the sub shaft guide groove 12. The movement is controlled.
[0026]
An objective lens driving device 4 and an optical element 4 are accommodated in the side surface of the frame or in the frame, and an FPC board 6 for supplying electric signals to the objective lens driving device 4 and the optical element 3 to control them is provided. Mounted or contained.
[0027]
As shown in FIG. 1, the frame 2 has an upper surface portion 13 on the optical recording disk side (hereinafter referred to as the upper surface side or upper side) and an outer peripheral edge of the upper surface portion 13 on the opposite side (hereinafter referred to as the optical recording disk). An outer peripheral wall portion 15 extending at a right angle to the lower surface portion 14. Such a frame 2 has an opening on one or both of the upper surface side and the lower surface side, and the objective lens driving device 4 and the optical element 3 are accommodated from the openings (upper surface side opening, lower surface side opening), If necessary, it is fixed to the frame with an adhesive or the like. Further, an upper surface cover 8 that covers the objective lens driving device 4 and an upper surface cover 9 that covers the optical element 3 are mounted on the upper surface side opening of the frame 2. On the other hand, a lower surface cover 10 that covers the objective lens driving device 4 is attached to the lower surface side opening of the frame 2.
[0028]
(Circuit board)
FIG. 3 is a plan view (a), a back view (b), and a circuit diagram (c) showing an example of the circuit board according to the first aspect of the present invention. The optical pickup device 1 shown in FIG. A circuit board to be mounted.
[0029]
The circuit board 21 according to the first aspect is configured by bonding an FPC board 24 and one or more metal plates 26 together.
[0030]
The FPC board 24 is a laminated board in which a wiring pattern 22 is formed between, for example, a base film made of polyimide and a cover film, and an electronic component is placed on a solder land on at least one surface (usually the surface on the cover film side). 25 is surface-mounted. In such an FPC board 24, a cut hole 23 is formed in an arbitrary shape for cutting a wiring pattern that is used only for performing an electric solder plating on a solder land.
[0031]
The metal plate 26 has a size including an area where the cut hole 23 is formed and an area where the electronic component 25 is mounted, and is bonded to the FPC board 24. For example, in FIG. 3B, a metal plate 26A having a size including a cut hole forming region and an electronic component mounting region and a metal plate 26B having a size including the electronic component mounting region are bonded to the FPC board 24. .
[0032]
In the metal plate 26 to be bonded, a hole 27 larger than the cut hole 23 is formed at a position corresponding to the cut hole 23 formed in the FPC board 24. FIG. 4 is an explanatory diagram of the relationship between the holes 27 formed in the metal plate 26 and the cut holes 23 formed in the FPC board 24. As shown in FIG. 4, it is desirable to form a large hole 27 in the metal plate 26 so that the sag 28 of the copper foil 32 on the side surface of the cut hole of the FPC board 24 does not contact the metal plate 26. It is desirable that the hole 27 has a gap G of about 0.3 mm from the side wall end face.
[0033]
The shape of the cut hole 23 formed in the FPC board 24 is not particularly limited to a round hole, a long hole, or a square hole. Therefore, the hole 27 formed in the metal plate 26 corresponding to the cut hole 23 is not limited. The shape of the hole is not limited.
[0034]
The material of the metal plate 26 is not particularly limited. For example, various metal plates such as a galvanized steel plate, a stainless steel plate, and an aluminum plate can be used. Moreover, the thickness should just be sufficient thickness to provide the function as a reinforcement board for mounting the electronic component 25, and although it changes also with the intrinsic strength derived from the material of a metal plate, it is 0. It may be a thickness of about 2 to 0.3 mm, and it is equivalent even if it is made thinner than the thickness (for example, about 0.5 to 0.8 mm) of a resin plate or a phenol resin plate containing conventional glass fibers. Strength can be given.
[0035]
The metal plate 26 is not necessarily provided in the region where the electronic component 25 is not mounted, but may be provided. Further, the FPC board 24 and the metal plate 26 can be bonded with, for example, an epoxy-based adhesive or an adhesive.
[0036]
In the circuit board 21 according to the first aspect, since a hole 27 larger than the cut hole 23 is formed in the metal plate 26 at a position corresponding to the cut hole 23, the sagging of the copper foil 32 is formed on the side wall of the cut hole 23. Even if 28 occurs, a short circuit between the sag 28 of the copper foil 32 and the metal plate 26 does not occur. Further, the metal plate 26 is effective as a reinforcing plate having a cost merit because dust such as glass fiber is not generated and the strength can be sufficiently secured.
[0037]
FIG. 5 is a schematic plan view (a), a schematic back view (b), and a schematic cross sectional view (c) showing an example of a circuit board according to the second aspect of the present invention. The circuit board 51 according to the second aspect is the same as the circuit board according to the first aspect described above in that the FPC board 52 and the metal plate 53 are bonded to each other. The insulator 54 is provided between the metal plate 53 and the metal plate 53.
[0038]
As the insulator 54, for example, an insulating film such as a polyamide-imide film can be used. The insulator 54 may be provided by being bonded between the metal plate 53 and the FPC board 52, or a resin composition such as an epoxy resin may be used as a metal. It may be applied on a plate and the FPC board 52 may be bonded thereon. In FIG. 5A and later-described FIG. 6A, reference numeral 56 denotes an insertion hole for the laser diode 16, and in FIG. 5B and later-described FIG. 6B, reference numeral 57 denotes the insertion hole. 56 is a hole corresponding to 56.
[0039]
The area of the insulator 54 only needs to be larger than the end portion of the cut hole 55 formed in the FPC board 52, and is desirably about 0.3 mm larger than the end portion of the cut hole 55, for example. In the case of having two or more cut holes 55, it is convenient to form with an area including them. Note that a metal plate 53 provided with an insulator 54 (insulating film) on the entire surface on the side bonded to the FPC board 52 may be used.
[0040]
The thickness of the insulator 54 made of an insulating film, an insulating film or the like is a thickness that does not break through the copper foil and can be arbitrarily set in relation to the insulation resistance derived from the material of the insulator. However, it is usually preferable that the thickness is about 10 to 50 μm.
[0041]
Next, another aspect of the circuit board of the present invention will be described.
[0042]
6 is an example of a circuit board 61 in which the ground terminal 63 of the FPC board 62 and the metal plate 64 are electrically connected. FIG. 6A is a plan view of the circuit board 61, and FIG. FIG. 4C is a back view, FIG. 3C is a plan view of the metal plate 64, and FIG. In this circuit board 61, as in the first embodiment described above, an FPC board 62 having a cut hole 67 and a metal plate 64 having a hole 68 of a predetermined size at a position corresponding to the cut hole 67 are bonded together. ing.
[0043]
In this embodiment, the metal plate 64 is preferably a copper-clad laminated metal plate in which a copper foil 66 is provided on an iron plate 65, for example. The copper foil 66 may be formed on the entire surface of the iron plate 65 or formed in a predetermined size as shown in FIG. 6C, but is not particularly limited, but at least the ground terminal 63 of the FPC board 62. It is necessary to be formed below.
[0044]
Such a metal plate 64 is bonded to the FPC board 62 and soldered to the ground terminal 63 of the FPC board 62 by solder 69. As a result, the ground of the circuit board can be strengthened and the influence of noise can be eliminated. In addition, although the copper clad laminated metal plate which provided the copper foil 66 on the iron plate 65 was used as the metal plate 64 here, it is not necessarily limited to this aspect, The kind of metal materials, such as the copper foil 66 and the iron plate 65, It is also possible to change the laminated structure. The circuit board 61 of this aspect has the same effects as the first and second aspects described above and is effective as a noise countermeasure.
[0045]
FIG. 7 is an example of a circuit board 71 of the present invention using a copper-clad laminated metal plate in which a wiring pattern 70 is formed on a metal substrate 77 via an insulating film 76 as a metal plate 74. FIG. 5B is a plan view of the circuit board 71, FIG. 5B is a plan view of the metal plate 74, and FIG. The circuit board 71 omits the same cut holes as those of the first and second aspects described above, but naturally includes the first and second aspects, the FPC board 72 having the cut holes, A metal plate 74 having a hole or insulator having a predetermined size is attached to a position corresponding to the cut hole.
[0046]
In this embodiment, the insulating film 76 may be provided on the entire surface of the metal base 77 or may be formed in a shape slightly larger than the wiring pattern 70 made of the copper foil 75. Although not particularly limited, it is necessary that the metal substrate 77 and the wiring pattern 70 made of the copper foil 75 be formed in a shape that can be insulated. Further, the wiring pattern 70 is a pattern for connecting to the land of the FPC board 72 to form a new circuit pattern on the metal plate, and the degree of design freedom of the circuit board 71 can be remarkably improved.
[0047]
Such a metal plate 74 is bonded to the FPC board 72, and a soldering land 78 formed on the metal plate 74 and a connection terminal 73 of the FPC board 72 are connected by solder 79. As a result, the design flexibility of the circuit board 71 can be significantly improved. In addition, although the copper clad laminated metal plate which provided the wiring pattern 70 of the copper foil via the insulating film 76 on the metal base material 77 as the metal plate 74 was used here, it is not necessarily limited to this aspect, It is also possible to change the type of metal material and the laminated structure.
[0048]
【The invention's effect】
As described above, according to the circuit board of the present invention and the optical pickup device including the circuit board, even if copper foil sags on the side wall of the cut hole, a short circuit between the wiring pattern and the metal plate does not occur. . In addition, since a metal plate is used as the reinforcing plate, it can be made thinner if it has the same strength as the reinforcing plate made of resin. It can be used in places where there is no impact and cleanliness is required.
[0049]
Further, according to the circuit board of the present invention, it is possible to take measures against noise of the FPC board by positively connecting the ground terminal of the FPC board to the metal plate. In addition, the reinforcing plate is a copper-clad laminated metal plate, and by connecting the copper layer of the metal plate and the wiring pattern of the FPC board, the degree of freedom of wiring on the circuit board can be remarkably improved, and high density Wiring can be made possible.
[0050]
Since the optical pickup device of the present invention includes such a circuit board, the optical pickup device can be a stable quality optical pickup device, and dust or the like derived from the reinforcing plate is not electrostatically attached to an optical element such as a lens. Does not interfere with properties.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an optical system of an optical pickup device of the present invention.
FIG. 2 is a configuration diagram showing an example of an optical pickup device to which the circuit board of the present invention is preferably mounted.
FIG. 3 is a schematic view showing an example of a circuit board according to the first aspect of the present invention.
FIG. 4 is an explanatory diagram of a relationship between holes formed in a metal plate and cut holes formed in an FPC board.
FIG. 5 is a schematic view showing an example of a circuit board according to a second aspect of the present invention.
FIG. 6 is an example of a circuit board in which a ground terminal of an FPC board and a metal plate are electrically connected.
FIG. 7 is an example of a circuit board of the present invention using a copper-clad laminated metal plate made of a copper foil, an insulating film and a metal substrate processed into a wiring pattern as a metal plate.
FIG. 8 is an explanatory view showing a mode in which a short circuit occurs when a sag of a copper foil comes into contact with a metal plate when a hole is made in a wiring pattern of an FPC board to cut off electrical signal conduction.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Optical pick-up apparatus 2 Frame 3 Optical element 4 Objective lens drive apparatus 5 Optical recording disk 6, 24, 52, 62, 72, 85 FPC board 7 Objective lens 8, 9 Upper surface cover 10 Lower surface cover 11 Main shaft guide hole 12 Sub shaft guide Groove 13 Upper surface portion 14 Lower surface portion 15 Outer peripheral wall portion 16 Laser diode 17 Beam splitter 18 Lens 19 Reflection mirror 21, 51, 61, 71 Circuit board 22, 70, 81, 82 Wiring pattern 23, 55, 67, 83 Cut hole 25 Electronic component 26, 26A, 26B, 53, 64, 74, 84 Metal plate 27, 68 Hole 28, 90 Sag 29, 89 Adhesive 30, 86 Base film 31, 80, 88 Cover film 32, 66, 75, 87 Copper foil 54 Insulator 63 Ground terminal 65 Iron plate 69, 79 Solder 73 Connection terminal 76 Film 77 metal base 78 land

Claims (5)

A circuit having a flexible printed circuit board in which a cut hole of a wiring pattern is formed, and one or more metal plates bonded to an area including the wiring pattern cut hole forming area and the electronic component mounting area of the flexible printed circuit board A substrate,
A circuit board, wherein a hole larger than the wiring pattern cut hole is formed in the metal plate at a position corresponding to the wiring pattern cut hole. A circuit having a flexible printed circuit board in which a cut hole of a wiring pattern is formed, and one or more metal plates bonded to an area including the wiring pattern cut hole forming area and the electronic component mounting area of the flexible printed circuit board A substrate,
A circuit board, wherein an insulator having a larger area than the wiring pattern cut hole is provided on the metal plate surface at a position corresponding to the wiring pattern cut hole. The circuit board according to claim 1, wherein a ground terminal of the flexible printed circuit board and the metal plate are electrically connected. The metal plate is a copper-clad laminated metal plate in which a wiring pattern is formed on a metal substrate via an insulating film, and the wiring pattern of the copper-clad laminated metal plate is electrically connected to the wiring pattern of the flexible printed circuit board. The circuit board according to claim 1, wherein a circuit pattern is configured. An optical pickup device comprising the circuit board according to claim 1.

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