JPH0918111A - Fixing structure for electronic device - Google Patents

Abstract

PURPOSE: To enhance the bonding strength by forming a bonding land on a copper foil adhesion layer and then bonding a movable member thereto through a bonding agent. CONSTITUTION: A bonding land 10 is provided at a part for securing a movable member 8. The land 10 is formed on the basic material 2 of a circuit board 1 applied only with a copper foil adhesion layer 3. When a resist is applied in order to protect a pattern, the bonding land part can be coated with a protective film which can be removed after application of resist. Alternatively, the cured resist and indication print may be removed by means of chemical or mechanical polishing. This structure enhances the bonding strength stably for a long term thus enhancing the reliability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing structure for fixing electronic parts constituting a circuit to a circuit board.

[0002]

2. Description of the Related Art When an electronic component is mounted on a circuit board such as a printed wiring board, there is one in which a terminal of the component is fitted into a hole formed in a land of a pattern forming the circuit board and fixed by soldering. Due to restrictions in pattern design, etc. in addition to the mounting of conventional electronic components, a wire rod is pulled out from the land, and the wire rod is made to crawl across the pattern that constitutes a circuit different from the circuit to which this land belongs and is made to conduct to the functional member. In some cases, a functional component such as a capacitor may be arranged along the pattern as a component to be attached later.

When the circuit board has a pattern for sending a drive signal to a drive member such as a motor, the circuit board is often placed in the same housing as the drive member and in close proximity to the drive member. The circuit board undergoes mechanical vibration due to the rotation, and the above-mentioned wire and functional parts rub the pattern of the circuit board during long-term use, breaking the pattern and the wire itself, or short-circuiting the pattern and the wire and functional parts. The drive member may stop functioning or the drive member may be destroyed.

Therefore, the movable member such as the wire is fixed to the circuit board so that the movable member cannot be easily moved even if such vibration occurs. For example, the movable member is bound by a binding member provided on the circuit board, or after the electronic component is mounted on the circuit board, the movable member is printed with a resist or a display printing pattern such as an adhesive or an adhesive. A method of fixing with a fixative is used.

However, in the method of fixing with the binding member, the binding member is required in addition to the circuit board, and an extra man-hour is required for processing the binding member. In many cases, they are bound, and in this case, the binding member may increase the dimension of the motor in the thickness direction, which hinders the reduction in thickness of the motor.

The method of fixing with a fixing agent can prevent protrusion in the vertical direction of the substrate, unlike the case of binding with the above-mentioned binding member, but it is fixed on a resist or a pattern on which display printing is applied. At this time, if the wettability or the affinity of the interface between the resist or the display printing and the fixative is poor, the fixing strength is lowered, and the fixative may not function in long-term use. For example, in resists and display printing, hydrophobic members are often cured, and when an oil film or the like remains on the surface or when a group with weak affinity is oriented at the interface, it is used as a fixing agent. Even if the agent is used, its adhesiveness is poor and it seems that it is temporarily adhered, but it may fall off during long-term use.

FIG. 3 is a sectional view showing the structure of the circuit board and the case where the circuit board is fixed by such a fixing method. In the figure, a circuit board 1 has a copper foil 4 constituting a conductive pattern adhered to an insulating base material 2 with a copper foil adhesive layer 3, and a pattern protection resist 5 is applied after the pattern is completed. Printing 6 is applied.

The base material 2 is a resin plate or resin film made of phenol resin, polyester, epoxy resin or the like, and a member made of a metal plate such as an iron plate insulated with a metal oxide film or resin for reinforcement and magnetic shielding. used. An adhesive such as an epoxy adhesive is attached to the base material 2 to form the copper foil adhesive layer 2, and then the copper foil 4 is stacked and pressed and heated to form a conductive member on at least one surface. A substrate is formed.

A land is printed on this board as a desired pattern or a current-carrying terminal by drawing with a photolithography, and it is etched with a corrosive chemical such as iron chloride to remove the copper foil portion other than the pattern and the current-carrying terminal from the base material 2. After forming a hole for inserting a functional component terminal for holding a functional component on the land or shaping the pattern, a resist 5 for pattern protection is applied to a portion other than the land, and then a display for component display is performed if desired. Printing 6 etc. is performed and it is set as a circuit board. Therefore,
At least the resist 5 is coated on the pattern except the land.

When the movable member 8 such as a wire or a capacitor is drawn on and crawled on the pattern or the display print 6 on which the resist 5 is applied, an adhesive 9 is attached to the pattern on which the resist 5 or the display print 6 is applied. And then fix it,
The resist 5 is not originally formed with a member suitable for joining in anticipation of joining with the adhesive 9, and since the wettability of the interface and the affinity with the adhesive are poor, it will fall off during long-term use as described above. It is a thing.

There is a strong demand for miniaturization and improvement in reliability of electronic equipment using circuit boards. The driving members such as the motors described above are more strongly thinned and improved in reliability, and these can be achieved by reducing the size of each constituent member and increasing the reliability of each member. At this time, the circuit board attached inside the motor housing cannot be easily repaired once it is installed, and the above-mentioned detachment significantly impairs reliability.

In addition to mounting the electronic parts on the circuit board described above, in fixing small parts to the circuit board, after sticking an adhesive or the like on one surface of the electronic part, the terminals and the land are aligned. Then, the circuit board is temporarily fixed with the adhesive or the like, and the land and the terminal are fixed by reflow soldering.

In this case, temporary fixing must be surely performed until the reflow soldering is completed, but if the surface on which the resist 5 or the display print 6 is applied and the above-mentioned adhesive are not wet well, the reflow soldering is performed before the reflow soldering. Electronic components mounted on the circuit board may fall off. This repair requires man-hours.

[0014]

Therefore, according to the present invention, in order to increase the reliability of the fixation between the circuit board and the movable member, it is possible to form the movable land by forming an adhesive land, which is compatible with an adhesive agent, on the circuit board. It is an object of the present invention to provide a circuit board in which the fixing strength between the member and the circuit board is enhanced.

[0015]

An electronic component fixing structure of the present invention is an electronic component fixing structure for fixing an electronic component constituting an electronic circuit to a circuit board by using a fixing agent. The land for joining is formed in the joining portion of the circuit board to be formed, and this joining land is characterized in that only the copper foil adhesive layer is applied to the base material of the circuit board. And

[0016]

[Function] A land for adhesion is formed on a portion of the base material of the circuit board where only the copper foil adhesive layer is applied, and the land and the movable member are movable at this position without resist or display printing. By fixing and using an adhesive or an adhesive, the wettability and the affinity at the interface between the circuit board and the movable member are improved, and the fixing strength is prevented from decreasing.
As a result, it is possible to improve the reliability of the device because it is stably fixed for a long period of time.

[0017]

1 is a sectional view showing an embodiment of the structure of a circuit board according to the present invention. 2 is a sectional view showing another embodiment of the structure of the circuit board according to the present invention. The same members as those in the conventional example shown in FIG. 3 are designated by the same reference numerals. Further, the description overlapping with that of the conventional example described above will be omitted.

In FIGS. 1 and 2, a land 10 for joining is formed at a joining portion for fixing the movable members 8 and 8-1 such as wires and functional parts.
The bonding land is formed on the base material 2 of the circuit board 1 on which only the copper foil adhesive layer 3 is applied.

When a resist for pattern protection is applied to the bonding land 10 in addition to the soldering land, a protective film is coated so that the resist does not cover the bonding land, and the resist is finished. After removing the protective film, it may be used as a land for bonding, or by applying resist on the pattern other than the land for soldering and hardening the resist and display printing, the resist is removed with a chemical solution or mechanical polishing. It may be used for land.

Movable members 8 and 8-1 made of functional parts such as wires and capacitors are attached to the bonding lands 10 of the circuit board according to the present invention having the above-mentioned structure by the adhesive 9,
When the copper foil adhesive layer 3 is attached and fixed later by using 9-1 or the like, the copper foil adhesive layer 3 has good wettability and affinity at the interface with the adhesive or the like, so that the copper foil adhesive layer 3 is reliably connected. Further, since the surface of the bonding land has a surface roughness larger than that of the resist or the surface of the display printing portion, the anchoring effect is easily exerted and the adhesive strength is increased. Therefore,
Even if vibration occurs in the circuit board, it does not move easily, and stable fixation is ensured and functions in long-term use. Further, as shown in FIG. 2, the terminal 7 is securely held on the substrate until soldering 11 of the terminal to the pattern 7 of the movable member 8-1 is completed.

Even when the circuit board according to the present invention is placed close to a driving member such as a motor and is installed in the same box, it exhibits a high fixing and holding force against vibrations, and a highly reliable power supply board is completed, which is long-term. Shows stable operation in use.

[0022]

As described above, the land for adhesion is formed on the portion of the base material of the circuit board where only the copper foil adhesive layer is applied, and the land is not subjected to resist or display printing. By fixing the circuit board and the movable member at a position with an adhesive or a pressure-sensitive adhesive, it is possible to improve the wettability and affinity of the interface between the circuit board and the movable member and prevent the fixing strength from lowering. You can As a result, the fixing is stable over a long period of time, so that the reliability is improved.

Since the processing can be performed relatively thin in the thickness direction of the circuit board, the thickness of the electronic device to which the circuit board is attached can be set thin.

In the reflow soldering of small electronic parts, temporary fixing is surely performed until the reflow soldering is completed, so that not only the production reliability is improved, but also the man-hours for dropout repair can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a circuit board according to the invention.

FIG. 2 is a diagram showing another embodiment of the circuit board according to the invention.

FIG. 3 is a cross-sectional view of a conventional example showing a structure of a circuit board and a case where the circuit board is fixed by such a fixing method.

[Explanation of symbols]

 2 Base material 3 Copper foil adhesive layer 4 Copper foil 5 Resist 6 Display printing 7 Pattern 8 Movable member 9 Adhesive 10 Land for joining

Claims (1)

[Claims] 1. A fixing structure of an electronic component for fixing an electronic component constituting an electronic circuit to a circuit board by using a fixing agent, wherein a bonding land is provided at a joint portion of the circuit board to which the fixing agent is applied. The adhesive land is a fixing structure for electronic parts, in which only the copper foil adhesive layer is applied to the base material of the circuit board.