JPH10233593A - Smd driver module for el with electromagnetic shield and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute operations of an electromagnetic shield and electrostatic shield by providing a shield member using a metal material at an SMD driver module for an EL. SOLUTION: A shield cover 3 formed of a thin metal plate is mounted at a driver module. A magnetic material is preferable as material of the cover 3, and material having high shielding effect such as iron or nickel is used. A material cladded with copper foils on both surfaces without providing a shield cover of a separate component is sued for a circuit board. In the case of forming a pattern by etching, the foil is retained to cover overall surface of a lower surface of the board, used as a shield pattern 4, an hence a sufficient shielding effect is obtained. Since there is adverse influence if a shield member is not effectively grounded, a ground terminal 5 is formed at part of the cover 3 to have spring property. In the case of mounting at the board 1, it is brought into pressure contact with a through hole electrode used also as a ground wire of the electrodes at four corners and grounded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an SMD for EL, which is a surface mount circuit (SMD) for emitting light from an electroluminescent (EL) element used for display illumination in an electronic apparatus having a liquid crystal display device. Regarding the driver module.

[0002]

2. Description of the Related Art A backlight using an EL element is often used for illuminating a liquid crystal display device provided in a device such as a timepiece or a cellular phone, and an EL driver module for driving the backlight has been widely used. In order to reduce the size of these electronic devices, it is required to reduce the size of the driver module. However, the inventors of the present application have previously proposed, in Japanese Patent Application No. 8-356432, to configure an SMD driver module for EL by a surface mounting method, thereby making it possible to reduce the size of the EL driver module.

FIG. 7 shows the SMD module of the above application. FIG. 1A shows an SMD driver module 1 for EL.
01 is connected to the EL substrate 110, and FIG. 2B is a block diagram of a driver module circuit. The EL SMD driver module 101 is configured by surface-mounting circuit components on a circuit board 102 made of a material such as glass epoxy or paper phenol and having a conductive pattern formed on the surface. The components mounted on the surface are a chip IC (107) which is an active element, a chip capacitor 10
8, the inductance element 109 and the like. Circuit board 10
2 has connection terminals at four corners, and these are input terminals 104
a and 104b and output terminals 105a and 105b. The connection terminals are also on the lower surface of the circuit board 102, and the connection terminals on both sides of the board are connected by a conductive portion that covers the curved concave surface at the four corners of the board in FIG. As shown, the SMD driver module for EL 101 is connected to an EL substrate 110 by output terminals 105a and 105b, and the input terminals 104a and 104b are connected to a DC power supply 111 as shown in the circuit diagram of FIG.

[0004] The inductance element 109 is a rod-shaped coil having a magnetic core made of a magnetic material. The circuit board 102 is provided with a component accommodating portion 103 which is a hole or a depression, and both ends of the magnetic core are connected to a circuit pattern. At this time, the height of the module is prevented from increasing as much as possible by the coil being accommodated in the component housing portion 103. After the circuit components are surface-mounted in this manner, the circuit is buried by applying a resin coating 106 thereon to protect the components.

[0005] To manufacture this SMD driver module for EL, a large number of regions to be individual circuit boards are arranged in a grid on a collective substrate, which is a single material, and circuit components are surface-mounted in each region, and a resin is formed. After that, the collective substrate is cut vertically and horizontally and divided into individual EL SMD driver modules. That is, since many driver modules are manufactured in large numbers from one collective board, productivity is high. As described above, the circuit board 1 shown in FIG.
The conductors coated on the concave surfaces of the four corners of No. 02 connect the terminal electrodes on both surfaces of the substrate. The four corners are through holes in which a conductive film is formed on the inner surface of the collective substrate being processed. Since the cutting board is cut along the hole,
The four corners become concave surfaces covered with the conductive film.

[0006]

SUMMARY OF THE INVENTION The SM for EL of the aforementioned application
Although the D driver module is small and useful with high productivity, it is not without its problems. That is, since the driver module for EL includes a coil component in the circuit, it generates a changing magnetic field, but the resin covering the circuit protects the component mechanically and also protects against liquid, moisture, etc. There is no effect of electromagnetic shielding or electrostatic shielding. Therefore, (a) the electromagnetic noise generated from its own circuit becomes unnecessary radiation, and impairs the operation of other devices. (B) Malfunction may occur in its own circuit due to external electromagnetic noise or static electricity, or the IC may be destroyed. Etc. may occur. The present invention is directed to overcoming these problems.

[0007]

In order to achieve the above object, the present invention provides a shield member using a metal material in an SMD driver module for EL, thereby performing an electromagnetic shield and an electrostatic shield. As a structure of the shield member, first, there is a structure in which the module is covered with a metal shield cover. As another structure, metal plating is applied to the resin coating of the components on the module circuit board,
There is a structure used as a shield film. As yet another structure,
There is a structure in which a shield pattern is provided on a circuit board so as to surround a circuit pattern and a circuit component, thereby providing a shield function. The present invention fulfills the function of an electromagnetic shield and an electrostatic shield by using these structures alone or in combination.

Although it is naturally possible to form such a shield member for each of the individually divided single modules in terms of manufacturing, the present invention proposes to form the shield member during a processing step using a collective substrate. And thereby high productivity is obtained. It should be noted that the electromagnetic shield in the name of the present invention does not have a narrow meaning, but indicates a general shielding function including an electrostatic shield.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In the first embodiment, a shield cover is provided as a shield member. In FIG. 1A, the driver module has a resin coating 2 with components mounted on a circuit board 1 as proposed in the earlier application. A shield cover 3 made of a thin metal plate is attached to the driver module. The material of the shield cover 3 is most preferably a magnetic material, and a material having a high shielding effect, such as iron or nickel, is used. The shield cover 3 may be attached by any convenient method such as a method of press-fitting the outer periphery of the substrate 1 or a method of bonding to the substrate 1 using an adhesive.

If a shield cover is arranged on the lower surface side of the circuit board 1 as well, the shielding will be complete. However, even if a shield cover of a separate component is not provided, a circuit board made of copper foil on both sides can be used as a material. When a pattern is formed by etching, a sufficient shielding effect can be obtained by leaving a copper foil so as to cover almost the entire lower surface of the substrate as shown in FIG.

If the shield member is not securely grounded,
On the contrary, in the case of the first embodiment, when the ground terminal 5 is formed so as to have a spring property on a part of the shield cover 3 and is attached to the circuit board 1, through holes at four corners are formed in the first embodiment. Of the electrodes, the electrode is used as a grounding wire so as to be pressed and grounded. The situation is shown in Fig. 1 (C).
The shield cover 3 is shown in a partially cutaway sectional view. FIG.
In (B), the shield pattern 4 on the lower surface of the circuit board 1 has a shape connected to a ground line. In addition to the structure in which the ground terminal 5 of the shield cover 3 is connected to the conductive portion of the circuit board 1 as described above, when the driver module is mounted on a device,
It can also be connected to the device's motherboard.

Next, a second embodiment of the present invention will be described.
Here, a separate shield member such as a shield cover is not used. Instead, a metal coating is formed on the resin coating of the circuit component by electroless plating or the like, and this is used as a shield film. As shown in FIG. 2A, a resin coating 22 is provided with a shield film 23 on the upper surface, which is a plating layer, and shield films 24 and 25 on the side surfaces. On the lower surface of the circuit board 21, as in the first embodiment, a copper foil is left as a shield pattern 26 over a large area as shown in FIG. The plating layer on the side surface 25 extends over the side surface of the circuit board 1 and connects the shield film on the upper surface of the substrate to the shield pattern 26 on the lower surface of the substrate. As the type of plating,
Nickel plating is preferred from the viewpoint of the shielding effect.

In a third embodiment of the present invention, as shown in FIG. 3 (A), a shield pattern 33 is formed by leaving a copper foil in an area as large as possible around the upper surface of a circuit board 31. It is a member. Circuit board 3
As shown in FIG. 3B, a copper foil is left as a shield pattern 36 on a large area on the lower surface of 1 as in the previous embodiment. Therefore, although no shield film is provided on the resin coating 32, a shield film 34 is formed on the side surface of the circuit board 31 by plating, and the shield pattern 33 on the upper surface of the circuit board and the shield pattern 36 on the lower surface are connected. . In order to enhance the shielding effect, the shield pattern 33 on the upper surface of the circuit board has a closed shape that covers the periphery without a break, and the connection between the circuit pattern at the center other than the ground line and the terminal electrode at the corner is performed through the through hole 35. This is a structure performed on the lower surface side of the circuit board by the conductive pattern 37 on the lower surface of the circuit board in FIG.

As described above, the third embodiment utilizes a conductive pattern on a substrate as a shield member.
Since the structure is simpler than the first and second structures, the shielding effect is not as good as these. However, there is an advantage that a separate shield member or metal plating on a resin coating is not required, and the IC has It has considerable effects in terms of electrostatic protection.

The formation of the above-mentioned shield member on the EL SMD driver module, that is, the attachment of the shield cover, the plating of the shield film on the resin coating or the side surface of the circuit board, and the like are, of course, performed on a single driver module. However, as proposed in the above-mentioned application, the inventors assembled circuit components for a plurality of modules on a collective board for the manufacture of a driver module and cut it into many small pieces. Since the manufacturing method is intended, it is advantageous to form the shield member in the state of the collective substrate.

FIG. 4 shows a situation in which the driver module as shown in FIG.
In FIG. 1, a large number of regions serving as individual driver modules are arranged in a lattice. After assembling the circuit components in each area and applying the resin coating 42, the resin coating 42 is formed by electroless plating or the like.
Forming a metal film on the upper and side surfaces of the shield film 43;
44 and 45. The side shield film 45 is made of resin coating 4
2 and the inner peripheral surface of the elongated through hole 46 of the collective substrate 41, and a lower shield pattern (FIG. 2).
(B) 26). It is possible to form a long hole through hole 46 by providing a conductive film on the inner surface of the long hole by photolithography technology. Round hole through hole 4
Reference numeral 7 denotes a portion to be a terminal electrode at the four corners of the substrate when the driver module is completed.

After the circuit pattern is formed on the collective board in this way, round holes and long through holes are provided, the circuit components are assembled, the resin is covered, and the shield film is formed by plating. By cutting along dicing or slicing along the cutting line 48,
Individual finished products of the SMD driver module for EL with an electromagnetic shield are obtained.

When a circuit pattern formed on the collective substrate 41 is subjected to electrolytic plating, a conductive pattern called a common electrode is provided to keep all the patterns conductive. It is cut off at the opening or the last cutting step and becomes irrelevant to the circuit, but when the conductive layer is plated on the inner surface of the elongated hole to form the elongated hole through hole, the common electrode cut by the elongated hole is the edge of the elongated hole. In the case of an arrangement where the end faces are exposed and lined up, if the through holes are plated directly into the long holes, these end faces will be short-circuited and incorrect wiring will occur. Procedures such as providing an insulating film to prevent short circuit between common electrodes and then performing through-hole plating are required.

In the multi-cavity method shown in FIG.
Assembly board 51, long hole through hole 56, through hole 5
7 and the like are the same as those in FIG.
Is not performed independently for each region as shown in FIG. Then, plating is performed from above the resin coating 52 to form the shield film 53. When this is cut along the cutting line 58, a driver module with an electromagnetic shield as shown in FIG. 5B is obtained. By doing so, it is not necessary to coat the resin for each region, so that the process is simplified. However, since the end face 59 of the resin coating 52 is a cut surface, there is no shield film. To compensate for this, the plating of the shield film 53 can be performed on the entire upper surface of the resin coating 52 without being divided for each region. In short, various modifications can be made within the scope of the present invention.

FIG. 6 shows a situation in which a driver module shielded by a shield pattern as shown in FIG. 3 is manufactured on an aggregate board. A shield pattern 63 is provided on the aggregate board 61 for each of a large number of driver modules. Is formed. Similar to the collective substrate in FIGS. 4 and 5 described above, a hole is formed by combining a long through hole 66 extending to the left and right and a round through hole 67.
Further, a long hole through hole 69 is provided in a direction orthogonal to the long hole through hole 66, and a metal film is formed on the inner surface by plating. Thus, when the collective substrate 61 is cut along the cutting line 68, the obtained individual driver modules have the shield films 34 on the four side surfaces of the circuit board 31 as shown in FIG. Although not shown in FIG. 6, it is needless to say that the circuit components are thereafter covered with resin and protected as in the previous embodiment.

In the case where the shield cover 3 of the first embodiment shown in FIG. 1 is provided, the shield cover may be attached to each area of the collective board as shown in FIGS. In the case of the collective board 41 of FIG. 4, the shape of the side surface of the shield cover is
1 can be covered, but in a direction perpendicular to this, the upper surface of the collective substrate 41 stops at the upper surface and cannot extend to the side surface of the substrate. However, if the elongated through holes 66 and 69 are provided in the direction crossing each other as in the collective board 61 of FIG. 6, the shield cover shape covers most of the four side surfaces of the circuit board in the completed state of each module. I can do it.

Although some of the embodiments described above have their own effects, they can be used in combination. For example, since the shield pattern according to the third embodiment can be formed as a conductive pattern on a circuit board irrespective of other components, it is suitable to be used together with the first and second embodiments and the like, thereby further improving the effect. Can be enhanced.

[0023]

As described above, according to the present invention, there is provided a small-sized EL SMD driver module suitable for surface mounting, which is an electromagnetically and electrostatically shielded EL-equipped EL SMD driver module. Is achieved. Thus, (a) it is possible to prevent the electromagnetic noise generated from its own circuit from becoming unnecessary radiation, which would impair the operation of other devices. (B) It is possible to prevent a malfunction of its own circuit or breakage of an IC due to external electromagnetic noise or static electricity. This has the effect.

Further, the SMD driver module for EL with an electromagnetic shield according to the present invention can be manufactured in a large number of pieces using a collective substrate, so that the productivity is extremely high. As a result, a small and high-performance EL SMD driver module with an electromagnetic shield is provided at low cost, which contributes to miniaturization, high performance, and low price of electronic devices.

[Brief description of the drawings]

FIG. 1 is an SMD driver module for EL with a shield cover according to a first embodiment of the present invention, wherein (A) is a perspective view of the module and a shield cover, (B) is a perspective view of a lower surface of the module, and (C). FIG. 3 is a partial cross-sectional view of a module to which a shield cover is attached.

FIG. 2 shows an EL with a shield film according to a second embodiment of the present invention.
(A) is a perspective view of an SMD driver module for use in the first embodiment.
Is the upper surface of the module, and (B) is the lower surface of the module.

FIG. 3 is a perspective view of an EL SMD driver module with a shield pattern according to a third embodiment of the present invention;
(A) is the upper surface of the module, and (B) is the lower surface of the module.

FIG. 4 is a perspective view of an example of a method of manufacturing the EL SMD driver module with an electromagnetic shield according to the present invention in a number of pieces using a collective substrate.

FIGS. 5A and 5B are perspective views of another example of a method of manufacturing the EL SMD driver module with an electromagnetic shield according to the present invention in a multi-piece manner by using a collective substrate, wherein FIG. 5A is a collective substrate, and FIG. There is a module.

FIG. 6 is a perspective view of yet another example of a method of manufacturing the EL SMD driver module with an electromagnetic shield according to the present invention in a number of pieces using a collective substrate.

7A is a perspective view of a conventional EL SMD driver module, and FIG. 7B is a block diagram of a circuit.

[Explanation of symbols]

1, 21, 31 Circuit board 2, 22, 32, 42, 52 Resin coating 3 Shield cover 4, 26, 36, 63 Shield pattern 5 Ground terminal 23, 24, 25, 34, 43, 44, 45, 53 Shield film 35, 47, 57, 67 Through hole 41, 51, 61 Assembly board 46, 56, 66, 69 Slotted through hole 48, 58, 68 Cutting line

Claims (7)

[Claims] 1. An EL SMD driver module with an electromagnetic shield, comprising an EL driver module having a surface mounting structure, comprising a shield member. 2. The EL with the electromagnetic shield according to claim 1.
An SMD driver module for EL with an electromagnetic shield, wherein the shield member is a metal shield case. 3. The EL with the electromagnetic shield according to claim 1.
SMD driver module for EL, wherein the shield member is a metal shield film formed from a resin covering a circuit, and the electromagnetically shielded SMD for EL.
Driver module. 4. An EL with an electromagnetic shield according to claim 1.
Wherein the shield member is a metal shield pattern formed on a circuit board so as to surround the circuit.
SMD driver module for L. 5. The electromagnetically shielded EL SMD driver module according to claim 2, wherein the shield member has a metal shield pattern formed on substantially the entire lower surface of the circuit board. SMD driver module with EL. 6. An EL with an electromagnetic shield according to claim 2.
With electromagnetic shield, wherein the shield case is grounded in the SMD driver module for
SMD driver module. 7. The electro-magnetically shielded SMD driver module according to claim 2, wherein the shield member is formed on a collective board of the module. EL
Of manufacturing SMD driver module for use