JP2581811B2 - Clip-type lead frame - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clip type lead frame used for external leads of a hybrid IC, and a hybrid IC in which external leads are assembled using the clip type lead frame.

[Conventional technology]

Hybrid with many external leads on circuit board
In an IC, a clip-type lead frame is generally used as an external lead for assembly.

Next, FIG. 7 shows the structure of a conventional clip-type lead frame and a hybrid IC using the lead frame. In FIG. 1, reference numeral 1 denotes a hybrid IC substrate, 2 denotes a lead mounting electrode of a circuit pattern formed on the substrate 1, and 3 denotes a clip-type lead frame mounted on the substrate 1. Here, the clip type lead frame 3 has lead pieces 5 arranged in a comb shape with one end connected to the side rail 4, and the tip of each of the lead pieces 5 has a bifurcated bent clip portion. 6 are formed. Note that 6a, 6
b is the upper and lower jaws of the clip part 6.

Such a clip-type lead frame was manufactured by pressing a strip-shaped metal plate to stamp the side rails 4 and the lead pieces 5 at the same time, and then bending the tip of each lead piece 5 to form a clip portion 6. Things. To assemble the external leads to the substrate 1 of the hybrid IC, first, as shown in the drawing, the external leads are attached to the substrate 1 and the substrate 1 is sandwiched between the clip portions 6 of the lead frame 3. 6 (upper jaw 6a in the example shown)
And the lead mounting electrode 2 on the substrate side are soldered. Next, each lead piece 5 is cut into a predetermined length at once,
Separate from the side rail 4. In this case, if there is an idle lead piece that is not used, the lead piece is extracted from the substrate 1. When the substrate 1 is a single-sided metal insulating substrate, the substrate 1 is in contact with the rear surface of the substrate in order to prevent the clip portion 6 from electrically shorting between the front surface and the rear surface of the substrate. Between the lower jaw 6b of the clip part 6 and the substrate 1, an insulating spacer 7 is previously inserted as shown in the drawing.
And between the clip part 6.

[Problems to be solved by the invention]

By the way, the above-mentioned conventional clip-type lead frame and a hybrid IC in which external leads are assembled using the lead frame have the following disadvantages.

(1) After cutting the lead pieces by soldering the lead frame to the board, if there are free lead pieces that are not connected to the circuit on the board side, it is necessary to manually remove unnecessary lead pieces one by one, After that, processing work takes time.

(2) When the substrate is a single-sided metal insulated substrate, it is necessary to insert an insulating spacer between the tip clip portion of the lead piece and the substrate, and the assembling work is troublesome.

(3) If the clip dimensions of the lead frame do not match the thickness dimension of the board, the clip section may not be stably mounted on the board and may fall off the board before the soldering process. Therefore, a manufacturer that produces a wide variety of hybrid ICs on substrates having different thickness dimensions needs to prepare various types of lead frames having different dimensional standards according to various substrates, which makes component management difficult.

(4) In a conventional lead frame, the width dimension and lead pitch of each lead piece are constant, and a hybrid IC having a current terminal of a power output section and a voltage terminal (a small current) of a control signal system is required. In addition, it is necessary to separately wire using two types of lead frames having different widths of the lead pieces, which increases the number of assembly steps.

(5) Since the clip portion is formed in a forked shape at the tip of the lead piece, the position of the lead attachment electrode on the substrate side needs to be provided near the periphery of the substrate in accordance with the shape and size of the clip portion. For example, circuit patterns of hybrid ICs are limited in terms of design. For this reason, there is an inconvenience that the lead frame cannot be used for a hybrid IC in which the external lead attachment electrode is formed at a position recessed from the peripheral edge of the substrate.

The present invention has been made in view of the above points, and solves the above-described conventional problems, is widely used, and has a clip-type lead frame for a hybrid IC that is easy to dispose after soldering to a substrate. And a hybrid IC capable of expanding the degree of freedom in designing circuit patterns.

[Means for solving the problem]

In order to solve the above-mentioned problems, the present invention provides: (1) a clip-type lead frame having independent upper and lower jaw lead pieces arranged in a comb shape with one end connected to a side rail; The tip of each of the upper and lower jaw lead pieces has at least a first bent portion bent downward from the side rail side toward the side of the substrate and a second bent portion bent toward the surface of the substrate. A first bent portion of the lower jaw reed is bent on the side rail side from the first bent portion of the upper reed, and is longer than a first bent portion of the upper reed; At least one of the first bent portions is in contact with the side surface of the substrate, and the second bent portions of the upper and lower jaw lead pieces are in contact with the upper and lower surfaces of the substrate, respectively. Bend it It is assumed that the shape.

[Action]

(1) In the clip-type lead frame having the above configuration, the upper and lower jaw reeds are separated from the base and branched to the side of the side rail to protrude in a comb-like shape. Have at least a first bent portion bent downward from the side rail side toward the side of the substrate and a second bent portion bent toward the surface of the substrate, and the first bent portion of the lower jaw lead piece. Is bent on the side rail side from the first bent part of the upper jaw lead piece, and is longer than the first bent part of the upper jaw lead piece. By inserting the lead frame into the circuit board and mounting it,
The substrate is sandwiched between the second bent portion of the upper jaw lead and the second bent portion of the lower jaw lead. In this state, after soldering between the lead mounting electrode on the board side and the tip of the lead piece that comes into contact with this, if the straight portion of each lead piece is collectively lead cut, the lead soldered to the board will be obtained. All of the side rails and unnecessary lead pieces will fall off at the same time by one lead cutting except for the pieces.

In addition, the upper and lower jaw lead pieces each have a sufficient overhang length from the side rail, so that lead frames of the same specification can be stably mounted on various substrates having different thickness dimensions. In this case, for example, by bending the first bent portion abutting on the side surface of the substrate to the lower jaw lead piece as a stopper, positioning can be performed so that the insertion depth into the substrate is constant.

In addition, by changing the tip shape of the lead piece, it can be used as a pin-type terminal lead, and by changing the width of the upper and lower jaw lead pieces to be large or small, a double-sided board can be used. For a hybrid IC having a power output circuit on the upper surface and a control circuit on the lower surface, a current lead and a signal voltage lead can be formed on the same lead frame.

(2) On the other hand, by assembling external leads to the hybrid IC using the above-described clip-type lead frame, the position of the lead mounting electrode on the substrate side does not necessarily have to be provided near the side edge of the substrate, but is slightly recessed. Can be connected to the lead frame even at a different position, and the degree of freedom in designing circuit patterns is increased accordingly. Therefore, a circuit design such as forming another circuit pattern between the lead mounting electrode and the side edge of the board or providing the lead mounting electrode at the center of the board is hardly affected by the lead frame. Is also possible.

〔Example〕

1 to 6 show an embodiment of the present invention, and the same members corresponding to FIG. 7 are denoted by the same reference numerals.

First, in each of the drawings, a clip type lead frame 3 according to the present invention is configured such that upper ends 8 and lower leads 9 of sufficient length are alternately arranged independently of one another along a side rail 4 with one end connected to the side rail. And the upper and lower jaw lead pieces 8 and 9 are connected to the lead mounting electrode 2 formed on the board 1 on the other side of the connection, and the leading end and the middle of the lead piece are formed. The substrate 1 is appropriately bent so as to have at least a first bent portion in the side direction and a second bent portion in the surface direction.

FIG. 1 shows a state in which the clip type lead frame 3 is mounted on the substrate 1 of the hybrid IC. The lead frame 3 is inserted into the substrate 1 from the side, and the distal end portion 8a of the upper jaw lead piece 8 is connected to the substrate side. A stopper portion 9b formed by bending the middle part of the lower jaw lead piece 9 at a right angle while holding the substrate 1 between the leading end portion 9a of the lower jaw lead piece 9 while being aligned with the lead mounting electrode 2 is formed. 1. Push the entire lead frame until it hits the side end surface of the lead frame. Thereby, the lead frame 3 is correctly positioned at a predetermined position with respect to the substrate 1 and is stably held. FIG. 2 is a partially enlarged view of the lead frame mounted state of FIG. 1 viewed from the side.

Next, in the mounting state shown in FIG.
And the tip 8a of the upper jaw lead piece 8 in contact therewith is soldered by, for example, a reflow soldering method. In a subsequent step, the straight portions of the respective lead pieces are cut at once along the chain line P shown in FIG. As a result, all of the side rails 4 and the lower jaw lead pieces 9 are simultaneously separated and dropped, leaving the upper jaw lead pieces 8 soldered to the substrate 1. In addition, if there is a play lead that is not soldered on the board side in the row of the upper jaw lead pieces 8, unnecessary lead pieces are simultaneously dropped and removed by the above-described lead cut.

FIG. 3 shows an embodiment in which the same lead frame 3 as in FIGS. 1 and 2 is applied to a substrate having a large thickness, and in this case also, the protruding length of the lead edge from the side rail 4 is shown. Since the length is sufficiently long, it can be securely mounted on the substrate 1 within the range of the bending allowance of the lead piece. That is, the present invention can be applied to various substrates having different thickness dimensions using lead frames of the same specification, and the versatility is improved accordingly.

In this case, even if the position of the lead mounting electrode 2 on the substrate side is retracted from the side edge of the substrate 1, the stopper portion 9b of the lower jaw lead piece 9 is bent in accordance with this. The distal end portion 8a of the upper jaw lead piece 8 can be correctly brought into contact with the lead attachment electrode 2, thereby increasing the degree of freedom in designing the circuit pattern on the substrate side. Therefore, another circuit pattern can be formed in the remaining space between the side edge of the substrate 1 and the lead mounting electrode 2, or the lead mounting electrode 2 can be arranged at the center of the substrate 1. Also, as shown in FIG. 1, by designing the width of the lower jaw lead piece 9 to be wide, for example, the lead frame 3 can be stably held in the state of being mounted on the board 1 and the upper jaw lead piece 8 after soldering can be obtained. Parallelism and squareness can be secured.

Next, FIGS. 4 and 5 show application examples different from the above. First, FIG. 4 shows that the pin portion 8b bent at the tip 8a of the upper jaw lead piece 8 is inserted into the pin hole 1a formed in the board 1, and the tip of the lower jaw lead piece 9 is simultaneously inserted into the double-sided mounting board 1. The surface mount type chip element 10 mounted on the back surface side of the substrate 1 at the portion 9a is interposed and temporarily fixed.
In this state, the substrate 1, the upper jaw lead piece 8, and the chip element 10
The chip element 10 to be mounted especially on the back side by performing reflow soldering between
The external leads and the chip element can be mounted and assembled at the same time without temporarily fixing the chip with an adhesive or the like.

FIG. 5 shows an application example in which an external lead is placed in a pin hole 1a drilled in the substrate 1 and soldered. A U-shaped bent portion 8c is formed at the tip of the upper jaw lead piece 8 of the lead frame 3.
Is formed, the insertion depth of the pins into the substrate 1 is set, and the substrate 1 is sandwiched between the lower jaw lead pieces 9 and temporarily fixed. Thereby, soldering can be performed while the external leads are stably held in the upright state.

FIG. 6 shows an embodiment of a clip-type lead frame applied to a double-sided mounting board in which external leads are drawn out from both upper and lower surfaces of the board. The lead pitch of the upper jaw lead piece 8, the lower jaw lead piece 9, and each lead are shown. The length dimension of the straight part of each piece is set as shown in the figure a, b, c, 1, l2, l3, and especially the lower jaw lead piece indicated by reference numeral 9d is used as a dummy lead piece for positioning To make the length of the straight part of the dummy lead piece l2 (l2> 1).
It is what it was. Then, when mounting the lead frame 3 on the mating substrate, the stopper portion 9b of the dummy lead piece 9d is positioned against the side end surface of the substrate. Accordingly, each of the lower jaw lead pieces 9 (length 1 of the straight portion) to be soldered to the back surface of the board except for the dummy lead piece 9d can be connected to the side end face of the board in a non-contact manner.

〔The invention's effect〕

Since the clip-type lead frame according to the present invention is configured as described above, its versatility is wider than that of a conventional lead frame in which a forked clip is formed at the tip of a lead piece connected to a side rail, and furthermore, An effect is obtained such that the work of removing unnecessary lead pieces after soldering to the board becomes easy.

Also, by assembling the external lead of the hybrid IC using the clip type lead frame of this structure,
In addition to widening the degree of freedom in designing circuit patterns for hybrid ICs, it can streamline the assembly process and improve product quality and reliability.

[Brief description of the drawings]

1 to 6 each show an embodiment of the present invention. FIG. 1 is a perspective view showing a state in which a clip-type lead frame is mounted on a substrate of a hybrid IC, and FIG. 2 is a partially enlarged view of FIG. FIG. 3 is a side view, FIG. 3 is a mounting state diagram of a lead frame applied to a substrate having a large thickness, FIGS. 4 and 5 are mounting state diagrams of a lead frame of an applied embodiment, and FIG. FIG. 7 is a perspective view showing the structure of a clip-type lead frame applied to a shaped substrate, and FIG. 7 is a state in which a conventional clip-type lead frame is mounted on the substrate. In the figure, 1: substrate, 2: lead mounting electrode, 3: clip-type lead frame, 4: side rail, 8: upper jaw lead, 9: lower jaw lead, 8a, 9a: tip.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kimio Yoshioka, Inventor 1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. No. 1 Inside Fuji Electric Co., Ltd. (56) References JP-A-63-138673 (JP, A) JP-A-6-17148 (JP, U)

Claims (1)

(57) [Claims] 1. A clip-type lead frame connected as an external lead to a substrate of a hybrid IC, comprising a comb-shaped independent upper jaw lead piece and a lower jaw lead piece connected at one end to a side rail. At least a first bent portion in which the distal ends of the upper and lower jaw lead pieces are bent downward from the side rails toward the side of the substrate and a second bent portion which is bent in the surface direction of the substrate. A first bent portion of the lower jaw reed is bent at a side rail side from a first bent portion of the upper reed, and is longer than a first bent portion of the upper reed. At least one of the first bent portions of the pieces comes into contact with the side surface of the substrate, and the second bent portions of the upper and lower jaw lead pieces come into contact with the upper and lower surfaces of the substrate, respectively, so that each lead is sandwiched between the substrates. Piece Clip-lead frame, characterized in that the molding is subjected to bending.