JP2005222589A - Wiring apparatus for head device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring apparatus for a head device, which enables a flexible wiring board to be formed of a single-layer substrate, can separately form a single-layer substrate and a multilayer substrate by a flexible wiring board and a subsubtrate, and reduces the area of using the multilayer substrate and therefore is cost-advantageous. <P>SOLUTION: A subsubtrate 15 to which an electric component 13 to be installed in a head device 1 is fitted is mounted on a flexible wiring board 5, the subsubstrate 15 is constituted of a double-surface substrate, and a connection pattern to be connected to a wiring pattern formed on the flexible wiring board 5 is formed on the backside of the subsubstrate 15 facing the flexible wiring board 5. Thus, the single-layer substrate is enough for the flexible wiring board 5 formed into a shape not to be efficiently taken out of a mold, and the range of the multilayer substrate used as the subsubstrate 15 is reduced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wiring for a head device that uses a flexible wiring board to connect a head device used for signal reading and / or signal writing on a signal recording medium and a circuit board installed in a device main body on which the head device is mounted. Relates to the device.

  2. Description of the Related Art Information recording / reproducing apparatuses that perform signal reading and / or signal writing on a signal recording medium such as a disk by a head device such as an optical pickup are known.

  In such an information recording / reproducing apparatus, generally, a head device is supported so as to be movable in a direction crossing a signal track of a signal recording medium, and is installed in the head device and a device main body on which the head device is mounted. A circuit board is connected using a flexible wiring board, and electrical signals are exchanged between the head device and the circuit board using the flexible wiring board.

  A wiring device of a head device that uses a flexible wiring board for connection between the head device and the circuit board of the apparatus main body is disclosed in, for example, Patent Document 1.

  By the way, when there is an electrical component to be mounted on the head device instead of the circuit board of the device main body, it is incorporated in a circuit pattern for installing each electrical component at a predetermined position on the side connected to the head device of the flexible wiring board or the head device. Circuit patterns to be connected to the electrical components are formed, and land portions are provided to which terminals of the electrical components corresponding to the respective circuit patterns are connected by soldering.

When the head device is an optical head device that optically reads and / or writes signals using laser light, a semiconductor laser that is a light source, a photodetector that receives laser light reflected by a signal recording medium, and the semiconductor Laser-driving semiconductor integrated circuit (laser-driving IC) for driving a laser, and a laser emitted from the semiconductor laser to maintain a predetermined intensity of a coil, a capacitor, a resistor, or a semiconductor laser for setting a circuit constant A front monitor diode that receives light is mounted on the head device, and these electrical components are connected to the flexible wiring board. (See Patent Document 2)
JP 2003-228866 A JP 2001-339182 A

  As described above, in the flexible wiring board used for connection between the head device and the circuit board of the apparatus main body, various electrical components are installed near the end on the head device side, or electrical components incorporated in the head device are connected. And since these various electrical components are arranged at a predetermined part of the head device by bending the flexible wiring board, etc., each installation part for installing each electrical component of the flexible wiring board branches into four branches in all directions. It has a complicated shape.

  By the way, when signal recording is performed on a DVD or CD, the semiconductor laser is driven by a driving current superimposed with a high frequency.

  Therefore, in the case of an optical head device compatible with DVD or CD signal recording, a laser drive IC mounted on the head device is equipped with a high frequency superimposing circuit, and a laser is used to set the high frequency oscillated by this high frequency superimposing circuit. Since a coil, a capacitor, and a resistor are required as external components of the drive IC, and an optical head device compatible with DVD is also compatible with CD, a dedicated semiconductor laser is often provided for each of DVD and CD.

  Therefore, when mounting a plurality of electrical components necessary for the head device on the flexible wiring board in this way, the flexible wiring board cannot be enlarged unnecessarily due to the mounting on the head device. It is necessary to use a multilayer substrate such as double-sided as a wiring substrate.

  In addition, when each drive circuit for driving each semiconductor laser is incorporated in the laser drive IC so that a single laser drive IC can be used for both the semiconductor laser for DVD and the semiconductor laser for CD, the laser drive IC is inserted. Since the number of output pin terminals is increased and the laser drive IC is downsized because it is necessary to be mounted on the optical head device, the laser drive IC has a configuration in which the pin terminal protrudes from any of the four sides of the package. (Quad in-line package), especially from the relationship between the laser diode for DVD and the semiconductor laser for CD, the front monitor diode and the coil, capacitor, and resistor for setting circuit constants. There are many conductive patterns and they are complicated by being wired vertically and horizontally.

  For this reason as well, it is necessary to use a multilayer substrate as a flexible wiring board on which electrical components necessary for the head device are mounted.

  When using a flexible wiring board as the wiring device of the head device, there is a lot of space in the layout design when taking out the flexible wiring board from the mold due to the relationship of the outer shape of the flexible wiring board, and the flexible wiring board can be taken out at the same time The number of printed wiring boards is not efficient, and the cost of a multilayer flexible wiring board is significantly higher than that of a single layer. Therefore, if a multilayer flexible wiring board is used as a wiring device for a head device, the cost of the flexible wiring board is increased. It becomes a problem.

  Reinforcing plates are bonded to the back surfaces of the flexible wiring board on which various electrical components are installed. When the flexible wiring board is bent by these reinforcing plates and placed at a predetermined portion of the head device, The installation surface of the electrical parts is not curved so that the installation surface is stabilized and the electrical components are prevented from coming off. However, the cost is increased by bonding these reinforcing plates to the flexible wiring board. It was.

  The present invention places a sub-board on which an electrical component installed in a head device is mounted on a flexible wiring board, the sub-board is constituted by a double-sided board, and the flexible wiring board is placed on the back surface of the sub-board facing the flexible wiring board. A connection pattern is formed to connect to the wiring pattern formed above. As a result, the flexible wiring board having a shape that cannot be efficiently taken out by the mold is sufficient by the single-layer board, and the range of the multilayer board used as the sub-board is reduced. Further, by placing the sub-board on which the electrical component is mounted on the flexible wiring board, the portion is reinforced without a reinforcing plate.

In the wiring device of the head device according to the present invention, the electric component installed in the head device is attached to the flexible wiring board to the sub-board configured by the double-sided board, so that the flexible wiring board can be a single layer board. In addition, the flexible wiring board and the sub board can be separately formed into a single layer board and a multilayer board, and the area using the multilayer board is small, which is advantageous in terms of cost.

  In addition, since the electrical components are installed on the sub-board and attached to the flexible wiring board, wiring crossing the electrical parts can be performed without increasing the width of the flexible wiring board by the conductive pattern formed on the back surface of the sub-board. In particular, in the case of a semiconductor integrated circuit for a laser driving circuit, since there are many wirings that intersect the semiconductor integrated circuit for a laser driving circuit, the semiconductor integrated circuit for a laser driving circuit is installed on a sub-board and attached to a flexible wiring board. Is valid.

  In addition, since the sub-board to which the electric component is attached is placed on the flexible wiring board, the electric power of the flexible wiring board can be obtained without attaching a reinforcing plate to the back surface of the flexible wiring board on which the electric component is installed. A necessary strength for maintaining the stability of the installation surface can be obtained on the component installation surface.

  FIG. 1 is a developed perspective view showing an embodiment of a wiring device for a head device according to the present invention, and FIG. 2 is a perspective view showing an example in which the wiring device for the head device shown in FIG. 1 is applied to an optical disk device.

  The optical head device 1 is supported by a screw shaft 3 and a guide shaft 4 so as to be movable in a direction crossing a signal track of a disk (not shown) placed on the turntable 2.

  A flexible wiring substrate 5 is drawn from the upper surface of the optical head device 1 in the moving direction of the optical head device 1, and the flexible wiring substrate 5 is folded back so as to sandwich the optical head device 1 in the thickness direction. The plug portion 6 serving as a simple contact is connected to a circuit board 7 installed in the apparatus main body, and forms a transmission path connecting the circuit board 7 and the optical head device 1.

  Various electrical components incorporated in or mounted on the optical head device 1 are connected to or installed on the flexible wiring board 5, and these electrical components include a semiconductor laser serving as a laser light source having a wavelength suitable for a predetermined disk. 11. Photodetector 12 for receiving the laser beam reflected by the disk, laser driving semiconductor integrated circuit (laser driving IC) 13 for driving the semiconductor laser, and a coil, a capacitor, and a resistor for setting circuit constants (not shown) Or a front monitor diode 14 for receiving the laser beam emitted from the semiconductor laser 11 in order to keep the emitted light quantity of the semiconductor laser at a predetermined intensity.

  When the laser driving IC 13 is installed on the flexible wiring board 5, as shown in FIG. 3, the laser driving IC 13 is previously attached to the sub board 15 by soldering, and the sub board 15 to which the laser driving IC 13 is attached is attached to the flexible wiring board 5. This is performed by overlapping the predetermined positions and fixing by soldering.

The flexible wiring board 5 includes predetermined electrical components, in this embodiment, a semiconductor laser 11 and a second semiconductor laser (not shown) adapted to a different disk at a position different from the semiconductor laser 11. In addition to the sub-substrate 15, a second sub-substrate 16 is installed at a predetermined location in relation to the arrangement position on the optical head device 1, and the second sub-substrate 16 is connected to each terminal of the semiconductor laser 11 and the second semiconductor laser. In this case, since the second sub-board 16 is sufficient as a single-layer board, a connection land in which the cover film is not covered on the front surface on which the wiring pattern is formed is formed corresponding to the wiring pattern. The second sub-board 16 is soldered to connect each of the connection lands to the corresponding connection land on the flexible wiring board 5, and the second sub-board 16 Installed in reluctance wiring board 5.

  The flexible wiring board 5 configured as described above has an outer shape as shown in FIG. 3, the solid line portion is folded in a mountain, the broken line portion is folded in a valley, and bent according to the outer shape of the optical head device 1. A site where the electrical component is connected or installed is set at a predetermined position of the optical head device 1.

  In this way, various electrical components, that is, the photodetector 12 and the front monitor diode 14 are installed at a predetermined position of the optical head device 1, or the semiconductor laser 11 incorporated at a predetermined position of the optical head device 1 is connected to the flexible wiring board 5. The laser drive IC 13 is installed at a predetermined corner on the back surface of the optical head device 1 as shown in a partial perspective view of the back surface of the predetermined portion of the optical head device 1 shown in FIG.

  In this case, the sub-board 15 is placed on the flexible wiring board 5 and the sub-board 15 is a double-sided board, and the ground pattern is formed on the sub-board 1. The strength of the portion where the laser driving IC 13 is installed is increased, and the laser driving IC 13 is stably installed at a predetermined position of the optical head device 1 without requiring a reinforcing plate.

  FIG. 5 is a cross-sectional view for explaining a cross section of each substrate in a state in which the sub-board 15 is placed on the flexible wiring board 5, and the flexible wiring board 5 is made of copper on a base film 5a made of a resin film such as polyimide. A foil conductive pattern 5b is formed, and the conductive pattern 5b is covered with a cover film 5c made of a resin film such as polyimide.

  On the other hand, the sub-board 15 is composed of a multilayer board on which wiring patterns are formed on both sides, and copper foil conductive patterns 15b and 15c are formed on both sides of a base film 15a made of a resin film such as polyimide, respectively. And 15c are coated with a liquid resist to form insulating surfaces 15d and 15e that are insulated, and the wiring patterns that need to be electrically connected to the conductive patterns 15b and 15c on the front and back sides are formed by a through-hole structure. Electrically connected.

  Connection patterns for electrical connection are formed on the installation surface of the flexible wiring board 5 on which the sub board 15 is installed and the installation surface of the sub board 15 installed on the flexible wiring board 5. And the site | part in which the said connection pattern of the installation surface of the flexible wiring board 5 is formed is not covered with the cover film 5c, and the connection pattern of the installation surface of the sub board | substrate 15 is formed. The part which is not subjected to the resist processing is exposed, and the sub-board 15 is placed on the flexible wiring board 5 so that the connection pattern of the sub-board 15 is connected to the connection pattern of the flexible wiring board 5.

  By placing the sub-board 15 on the flexible wiring board 5 in this way, a wiring pattern is formed by the flexible wiring board 5 and the sub-board 15 under the laser driving IC 13 without increasing the width of the flexible wiring board 5.

  In this case, since the laser drive IC 13 is installed on the sub-board 15 of the multilayer board and the wiring pattern on the back surface of the sub-board 15 is used effectively, the flexible wiring board 5 requires a complicated wiring pattern. The flexible wiring board 5 is sufficient as a single-layer board without increasing the width.

In addition, a ground pattern for electromagnetic shielding is formed on the projection surface of the laser drive IC 13 at a position avoiding the wiring pattern soldered to the terminals of the laser drive IC 13 on the installation surface of the sub-board 15 where the laser drive IC 13 is installed. Thus, the influence of the unnecessary radiation caused by the drive pulse generated by the laser drive IC 13 on the wiring pattern of the flexible wiring board 5 is suppressed.

It is a development perspective view showing one example of a wiring device of a head device concerning the present invention. It is a perspective view which shows an example which applied the wiring apparatus of the head apparatus shown in FIG. 1 to the optical disc apparatus. It is a top view explaining the bending method while showing the external shape of the flexible wiring board. 3 is a partial perspective view showing a back surface of a predetermined part of the optical head device 1. FIG. It is sectional drawing explaining the cross section of each board | substrate in the state which has arrange | positioned the sub board | substrate 15 on the flexible wiring board 5, and is arrange | positioned.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical head apparatus 5 Flexible wiring board 13 Semiconductor integrated circuit 15 for a laser drive Sub board | substrate

Claims (3)

In the wiring device for a head device, wherein a head device used for signal reading and / or signal writing on a signal recording medium and a circuit board installed in a device main body on which the head device is mounted are connected using a flexible wiring substrate, A sub-board with electrical components installed in the head device is placed on the flexible wiring board. The sub-board is composed of a double-sided board and formed on the back surface of the sub-board facing the flexible wiring board on the flexible wiring board. A wiring device for a head device, wherein a connection pattern connected to the wiring pattern is formed. 2. The wiring device for a head device according to claim 1, wherein a wiring pattern that bypasses the wiring pattern formed on the flexible wiring substrate is formed on the front surface of the sub-substrate. The head device includes a semiconductor laser as a light source for emitting a laser beam used for signal reading and / or signal writing on a signal recording medium, and an electrical component installed in the head device is a semiconductor integrated semiconductor for driving the semiconductor laser. 2. The wiring device for a head device according to claim 1, wherein the wiring device is a circuit component.

Images