JPH02278751A - Surface-mounted parts - Google Patents

Abstract

PURPOSE:To enable connection operation to a mother board to be performed easily by reflow, reduce mounting height, and enhance installation stability by making an electrode piece positioned within an expanded opening recessed part in non-contact state. CONSTITUTION:The lower-side opening of a penetration hole 2 for penetrating an electrode lead 25 formed at a base 1 is opened in a cut heat conical shape for forming an expanded opening recessed part 20, an insulating material 4 such as a kovar glass is filled into the penetration hole 2 excluding the expanded opening recessed part 20 for retaining an electrode lead 25, and an electrode piece 26 is turned into one piece at the lower edge part of the electrode lead 25. An electrode piece 26 is a conductive metal piece in conical form which is formed in one piece at the tip of lead while retaining a specified space to be in non-contact with the inner wall of the expanded opening recessed part 20 and the bottom surface of the expanded opening recessed part 20 and the bottom surface is machined in a flat surface shape. Thus, it becomes possible to perform connection operation onto a mother board easily by reflow, reduce mounting height, and improve installation stability.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a surface mount component in which an electronic component having lead terminals has an electrode structure suitable for surface mount.

(Prior Art) Conventionally, a piezoelectric device such as a water oscillator has been used to airtightly pass through a base made of a conductor block that has undergone the required molding process, and a piezoelectric device is attached to the end of a lead electrically insulated from the base. Generally, the piezoelectric device is permanently fixed and electrically connected by bonding the electrode lead portion with a conductive adhesive, and after the piezoelectric device is completely fixed to the base, this piezoelectric The device is covered with a cap and hermetically sealed with the base.

The electrode leads of such electronic components extend from the bottom surface of the base, and when connecting the electronic component to the printed circuit board, the electrode leads are inserted into the through holes of the printed circuit board and then the leads protruding from the other side of the board. The ends are soldered to wiring patterns etc. using the dip method.

i? When fixing the cap described in i on the base, a method is generally used in which welding pieces are applied to the lower and upper surfaces of the flange portion extending around the periphery of the base, respectively, and the welding is carried out by applying a predetermined current while applying pressure. .

By the way, the electronic components mentioned above are referred to as so-called through-hole type electronic components, but the workability when mounting these electronic components on printed circuit boards is similar to that of so-called surface-mounted electronic components, which can be connected using a reflow one-way method. This is significantly lower than what is possible.

For this reason, many attempts have been made to convert electronic components having two electrode leads into surface-mounted components.

That is, FIG. 5 is an explanatory diagram of the structure of the base portion of an electronic component as a first conventional example, in which an electrode lead 3 is inserted into a through hole 2 of a base 1 and extends from the through hole 2 to the entire bottom surface of the base. An insulating material 4 such as cover glass is integrated. Furthermore, the lower end of the lead 3 is connected to an electrode 6 on the bottom surface of the cover glass 4.

However, in order to weld the cap 7 to the base of such a mounted electronic component, the upper and lower welding pieces 10.1 are
If the base 1 and cap 7 are pressurized in step 1, there is a high risk that the cover glass will be damaged. Another problem arises in that the height of the entire component increases by the thickness of the cover glass and the electrodes.

Next, FIG. 6 shows a second conventional example, which is different from the conventional example in that the cover glass at the bottom of the 5 base l is provided only on the peripheral edge of the through hole 2, and the cover glass is not pressurized by the welding piece. Therefore, the problem of damage as described above does not occur, but there is no damage to the wiring pattern F. The problem of mounting height still remains unresolved.

(Object of the Invention) The present invention has been made in order to solve the problems of conventional surface mount components as described above. The purpose is to provide surface mount components that reduce the amount of damage caused by surface mounting and have high installation stability.

(Summary of the Invention) In order to achieve the above-mentioned object, a surface mount component according to the present invention includes a base having a flange for hermetically connecting the cap opening edge to the bottom periphery of the conductor block, and the base having a thickness. In an electronic component including an electrode lead inserted into a hole penetrating in the direction, [1] the distribution hole has an enlarged opening recess formed by expanding the -F end opening, and the above-mentioned The lower end of the electrode lead is integrated with a 1ffi piece located in the expansion recess in a non-contact manner, and furthermore, the bottom surface of the electrode piece protrudes below the bottom surface of the 1ii73a base. It is said that

Further, the present invention (5) is characterized in that the entire surface except the bottom surface of the base, the inner wall surface of the expansion recess, and the bottom surface of the front electrode piece is coated with a solder adhesion prevention paint.

(Examples) Hereinafter, the present invention will be described in detail based on examples shown in the accompanying drawings.

FIG. 1 is a sectional view of the base of a piezoelectric device package made into a chip component by applying the present invention.

The lower opening of the through hole 2 formed in the base 1 for inserting the electrode lead 25 is expanded into a truncated conical shape to form an expanded opening recess 20, and a through hole excluding the expanded opening recess 20. 2 is filled with an insulating material 4 such as cover glass to hold an electrode lead 25, and an electrode piece 26 is integrated at the lower end with an electrode ratio of 1:25.

This 7a pole piece 26 is a conical conductive metal piece that is integrated with the lead tip while maintaining a predetermined space so that it does not come into contact with the inner wall of the expansion opening recess 20, and its bottom surface is a flat surface. It is designed to increase the stability of installation on the wiring pattern of the printed circuit board. In addition, electrode piece 2
By making the bottom of the base 1 slightly protrude from the bottom of the base 1, it is possible to prevent a short circuit from occurring due to contact between the wiring pattern on the printed circuit board and the base.

When mounting a piezoelectric device package made into a chip component in this way on a printed circuit board, one electrode piece 26 is placed on the wiring pattern of the board via cream solder and connected by a solder flow. method, and the connection work can be made more efficient.

Note that the shape of the expanded opening recess 20 and the shape of the electrode piece 26 are not limited to those shown in FIG. 1; for example, as shown in FIG. or prismatic)
At the same time, the electrode piece 26 stored here is shaped like a cylinder (
Alternatively, it may be configured in a prismatic shape.

By the way, the problem with each of the embodiments shown in FIGS.
There is a risk that the capillary material may enter the ri' between the opening recess 20 and the expanded opening recess 20 due to capillary action, causing a short circuit between the two. Moreover, if the amount of downward protrusion of the electrode piece 26 is suppressed to the minimum necessary range, the gap between the wiring pattern of the board and the bottom of the base becomes small, but this gap is filled with solder and the pattern and base There is also a risk of short circuiting with the lower surface.

FIG. 3 shows an example of improvement of each of the above embodiments, and in terms of reflow,
A distinctive feature is that an insulating anti-solder coating 30 is applied or baked onto the entire bottom surface of the base, including the bottom peripheral surface of the electrode piece 26 and the inner wall of the expanded opening recess 20.

Examples of the paint used here include baking of amino alkyd resin, coating or baking of phthalic acid paint, or cloth of epoxy paint. It is important that any paint has insulating properties.

By forming a coating with the paint 30 described in L before reflowing, it is possible to avoid the possibility that solder melted during reflowing will enter the gap between the electrode piece 26 and the expanded opening recess 20 and cause a short circuit. Furthermore, the paint 30 coated on the bottom surface of the base serves to accurately prevent the occurrence of short circuits with patterns on the substrate.

Note that since the paint 30 is applied uniformly to the bottom surface of the electrode piece 26, it is necessary to remove only the paint on the bottom surface of the electrode piece 26 during reflow.

Thereafter, the cap is pressure welded to the base using a conventional method to complete the piezoelectric device package.

FIG. 4 is an explanatory diagram of the configuration of a polishing device for removing paint from the bottom surface of the N pole piece of structure F, and this polishing device is based on the base l.
A support frame 41 has a large number of recesses 40 along its length for storing and holding the support frame 41, a guide rail 44 formed on the product beads projecting on both sides of the recess 40, and a guide portion 46 that fits into the guide rail 44. A gantry type belt holding frame 48,
The polishing belt 52 is stretched around a plurality of rollers 50 that are rotatably supported by a belt holding frame 48. The polishing belt 52 has an abrasive surface capable of polishing the bottom surface of the electrode piece 26 extending from the base held in the recess, and is driven by the roller 50 to remove paint on the bottom surface of the electrode. Therefore, it is necessary to appropriately set the width, position, etc. of the belt so that it does not abrade the base or other parts.

A coil 54 is wound around the outer periphery of the support frame 41 to
A current is applied to the base to hold the base in the recess 40 magnetically.

In the above configuration, when the base l is held upside down in the recess 40 and the polishing belt 52 is driven and run, the polishing belt 52 can remove only the paint on the bottom surface of the electrode piece 26.

The base on which the electrode piece 26 has been polished is placed on the support frame 4.
1, the piezoelectric device package is completed by welding and fixing the cap opening edge in an airtight manner while applying pressure to the flanges on the outer peripheral edge of the base from above and below.

When mounting the electronic device package according to the present invention on a printed circuit board, the electrode piece 26 protruding from the bottom of the base is placed on a predetermined wiring pattern L via cream solder, and connected by reflowing. Complete T.

The protruding length of the electrode piece 26 is small, and the bottom surface of the base may come into contact with the wiring pattern due to the inclination of the entire package. However, since the bottom surface of the base is coated with the paint (insulating) 30, This does not cause any problems; on the contrary, the installation stability can be improved by bringing the bottom surface of the base into contact with the substrate.

Although the above embodiments have mainly been described with reference to a piezoelectric device package, the present invention is generally applicable to the case where a through-hole type electronic component having a base and leads is made into a chip component. For example, the present invention is applicable to power transistors, reed relay chips, etc.

In this way, a through-hole type electronic component can be converted into a surface-mounting chip component by simply adding a small amount of processing to the conventional base processing process. Furthermore, the components sit well before solder reflow, and there is no short circuit between the leads and the base due to solder.

(Effects of the Invention) As described above, according to the present invention, the connection work to the motherboard can be easily performed by reflow, the mounting height can be reduced, and the installation stability can be further improved. .

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the main part configuration of a piezoelectric device as an example of an electronic component to which the present invention is applied, FIG. 2 is an explanatory diagram of a modification of FIG. 1, and FIG. FIG. 4 is an explanatory diagram showing an example of a polishing apparatus, and FIG. 4 is an explanatory diagram of the configuration of a conventional example. 1...Base 2...Through hole lead 4...Insulating material 20. Location 25. . . Electrode lead 26 30... Paint area for preventing solder adhesion 41... Support frame 44.. 46..・Guided part 48... Root holding frame 50... Roller belt Figures 5 and 6 3... Electrode... Expansion opening concave... Electrode piece 40... Concave, guide rail, gantry type plate 52... Kenshin

Claims (2)

[Claims] (1) An electronic component comprising: a base having a flange for airtightly joining the cap opening edge to the bottom periphery of the conductor block; and an electrode lead inserted into a hole penetrating the base in the thickness direction; An expanded recess formed by expanding the lower end opening is formed in the through hole, and an electrode piece is integrated with the lower end of the electrode lead to be positioned in the expanded recess in a non-contact state. A surface mount component, characterized in that a bottom surface of the electrode piece protrudes below the bottom surface of the base. (2) The entire surface of the electrode piece except for the bottom surface, the bottom surface of the base, and the inner wall surface of the expansion recess are each coated with an insulating anti-solder coating. Surface mount parts.