JP6667301B2 - Electronic circuit board - Google Patents

Description

  The present invention relates to an electronic circuit board, and in particular, is suitably applied to an injection-molded board provided with a large current circuit corresponding to a large current and high heat radiation, such as an inverter circuit and a power supply circuit.

  Conventionally, on an electronic circuit board, a printed board in which a metal foil is cut in accordance with a wiring pattern and laminated with an insulating layer, and an injection molded board in which a metal plate (for example, a copper plate) is cut in accordance with the wiring pattern and integrally molded with an insulating resin. There is.

  In a printed circuit board, it is difficult to provide a stress relieving portion on the board side when increasing the stress concentrated on the electronic component to be mounted and the connection portion between the component boards (increase in cost, manufacturing difficulty). It was common to provide a relief section.

  An electronic component having a package structure has been proposed as an electronic component provided with a stress relaxation portion on the component side (for example, see Patent Document 1). In this electronic component, a crystal resonator housed in a cavity formed inside by a base and a lid, an electrode of the crystal resonator, and a through-hole electrode of a through-hole penetrating the base are connected to each other. A lead terminal connected thereto, and a bent portion (stress relieving portion) is formed between one end and the other end of the lead terminal.

  On the other hand, as shown in FIG. 13, the injection-molded substrate 1 includes a metal plate 2 made of a circuit conductor formed according to a wiring pattern, and an insulating member 3 molded by sandwiching the metal plate 2 with an insulating resin. And an electronic element 5 connected to the metal plate 2. The metal plate 2 is used as a so-called bus bar in the electronic circuit board 1.

  The insulating member 3 has an opening 3a formed of a through hole in which the insulating member 3 does not exist, and the two metal plates 2 are exposed in the opening 3a in a state where they are opposed to each other. I have. The surfaces of the tips of the two metal plates 2 are used as one (left) connection surface 2m and the other (right) connection surface 2m for mounting and connecting the electronic elements 5. The electronic element 5 is placed so as to straddle the connection surface 2 m of the two metal plates 2. One (left) electrode 5 b and the other (right) electrode 5 b of the electronic element 5 and the other One (left) connection surface 2m and the other (right) connection surface 2m are electrically connected by solder 4.

JP 2010-199678 A (page 4, FIG. 1)

  In the injection-molded substrate 1 having such a configuration, it expands when using the device on which the injection-molded substrate 1 is mounted or contracts when not in use. The coefficient of thermal expansion and the coefficient of thermal expansion of the electronic element 5 are different from each other. Therefore, since the degree of expansion of the metal plate 2 and the degree of expansion of the electronic element 5 are different from each other, the solder 4 may be affected by thermal stress and cracks may occur in the solder 4. If a crack occurs in the solder 4, the mechanical and electrical connection between the metal plate 2 and the electronic element 5 will be impaired.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a highly reliable electronic circuit board that does not impair the electrical and mechanical connection between an electronic element and a metal plate. That is.

  In order to achieve the above object, the present invention provides an electronic circuit board including a metal plate forming a circuit conductor, and an insulating member formed in a state where the metal plate is sandwiched, wherein the insulating member is An opening having no insulating member in a part thereof, wherein the metal plate is opposed to each other with the opening interposed therebetween, and one and the other bases respectively sandwiched by the insulating member; and an electronic element. One and the other connection portions respectively exposed at the openings so that the connection surfaces face each other with the connection surfaces interposed therebetween so as not to contact each other with the connection surfaces interposed therebetween. And the metal plate is bent so that the connection portion is at a different height position from the base portion, and has one and the other bent portions respectively connecting the base portion and the connection portion. .

  In the present invention, the connection surface is set at a height corresponding to a surface of the insulating member according to a bent state of the bent portion.

  In the present invention, the bent portion is not in contact with the insulating member.

  In the present invention, the connection portion has a flow-out prevention structure for preventing the flow of the solder to the bent portion on the connection surface.

  In the present invention, one electrode of the electronic element is connected to the one connection surface, and the other electrode of the electronic element is connected to the other connection surface, and the one connection surface is The other connection surface is mechanically and electrically connected by the electronic element.

  In the present invention, when the insulating member is laminated with an insulating member of another electronic circuit board, the connection surfaces are connected to each other.

  In the present invention, the connection portions are electrically connected to each other via solder between the connection surfaces.

  In the present invention, the connection portions are thermally connected to each other between the connection surfaces via a heat conductive sheet.

  In the present invention, the bent portion is a portion in which a part of a base portion of the metal plate that protrudes from the insulating member to the opening so as to face each other is cut and bent, and the opening of the portion is formed. Is less than half the length of the opening along the longitudinal direction of the metal plate.

  According to the present invention, it is possible to realize an electronic circuit board having high reliability without impairing electrical and mechanical connection between an electronic element and a metal plate.

FIG. 3 is a partial cross-sectional view, an enlarged cross-sectional view, and a top view showing the configuration of the electronic circuit board according to the first embodiment. FIG. 3 is a schematic diagram illustrating a relationship between a bending angle α of a bent portion of the electronic circuit board, a gap g, and a height h of a connection portion (connection surface) in the first embodiment. FIG. 3 is a partial cross-sectional view illustrating a bent state of a bent portion of the electronic circuit board according to the first embodiment. FIG. 3 is a partial cross-sectional view illustrating a relationship between a length of a metal plate of an electronic circuit board and an opening length D of an opening in the first embodiment. It is an expanded sectional view showing the solder flow prevention structure of the electronic circuit board in a 1st embodiment. FIG. 5 is a partial cross-sectional view illustrating a stress relaxation state when the electronic circuit board according to the first embodiment is affected by thermal stress. FIG. 4 is a partial cross-sectional view illustrating a state of solder application using a metal mask of the electronic circuit board according to the first embodiment. FIG. 3 is a partial cross-sectional view illustrating an electrical interlayer connection state of the electronic circuit board according to the first embodiment. FIG. 3 is a partial cross-sectional view illustrating a thermal interlayer connection state of the electronic circuit board according to the first embodiment. It is a partial sectional view showing the composition of the electronic circuit board in a 2nd embodiment. It is a partial sectional view showing the composition of the electronic circuit board in a 3rd embodiment. It is the fragmentary sectional view and top view showing the composition of the electronic circuit board in a 4th embodiment. FIG. 10 is a partial cross-sectional view showing a configuration of a conventional electronic circuit board and a state when the board is affected by thermal stress.

  Hereinafter, the first to fourth embodiments of the present invention will be described with reference to the drawings. It should be noted that the first to fourth embodiments described below are merely examples, and various forms can be taken within the scope of the present invention.

<First embodiment>
<Configuration of electronic circuit board>
The electronic circuit board 10 according to the first embodiment will be described with reference to FIGS. Here, in the figure, the longitudinal direction of the metal plate 12 of the electronic circuit board 10 is defined as the board horizontal direction (arrow ab direction), the arrow a direction is defined as the left side, and the arrow b direction is defined as the right side. In the drawing, the direction in which the metal plate 2 and the insulating member 3 of the electronic circuit board 10 overlap with each other is defined as the substrate vertical direction (arrow cd direction), the arrow c direction is defined as upper side, and the arrow d direction is defined as lower side.

  FIG. 1A is a partial cross-sectional view illustrating a configuration of an electronic circuit board 10 according to the first embodiment, and FIG. 1B is an enlarged cross-sectional view of a bent portion 12b. FIG. 1C is a top view of the electronic circuit board 10 to which the electronic element 5 is not connected. 1A and 1B are a partial sectional view and an enlarged sectional view corresponding to the XX section in FIG. 1C.

  As shown in FIGS. 1A to 1C, the electronic circuit board 10 is an injection-molded board, and includes an insulating member 3, a metal plate 12, and an electronic element 5. The insulating member 3 has insulating properties and is made of an insulating resin such as PPS (polyphenylene sulfide) having high heat resistance, and is formed by molding with the metal plate 12 sandwiched from above and below. is there. The insulating member 3 has an opening 3h formed of a through hole in which the insulating member 3 does not exist.

  The electronic element 5 is, for example, a chip capacitor or a chip resistor, and includes an element body 5a, and one (left) electrode 5b and the other (right) electrode 5b provided on the left and right sides of the element body 5a, respectively. It is configured. The electronic element 5 is electrically and mechanically connected to the metal plate 12. Specifically, the electrode 5b on one side (left side) of the electronic element 5 and the connection surface 12m of the connection portion 12c on one side (left side) of the metal plate 12 are electrically connected by the solder 4, and the other side of the electronic element 5 ( The electrode 5b on the right side and the connection surface 12m of the connection portion 12c on the other side (right side) of the metal plate 12 are electrically connected by the solder 4.

  The metal plate 12 is used as a so-called bus bar, and is a circuit conductor formed by punching a steel plate with a press die according to a wiring pattern. The metal plate 12 includes one (left) and the other (right) bases 12a, one and the other bent parts 12b, and the one and the other connection parts 12c which are arranged to face each other with the opening 3h interposed therebetween. And is bent in a substantially S-shape toward the tip as a whole. That is, each of the one (left) metal plate 12 and the other (right) metal plate 12 has a base portion 12a, a bent portion 12b, and a connection portion 12c, and has the same orientation except that the directions are opposite. Because of the configuration, the left metal plate 12 will be mainly described here for convenience.

  The base 12a of the metal plate 12 is a portion extending rightward (in the direction of arrow b) from the insulating member 3 toward the opening 3h while being sandwiched between the upper insulating member 3 and the lower insulating member 3. The tip is exposed to the opening 3h.

  The bent part 12b of the metal plate 12 is a part that connects the base part 12a and the connection part 12c. The bent portion 12b includes a bent portion 12ba bent upward (in the direction of arrow c) at the tip of the base portion 12a, and a straight portion that extends obliquely and linearly further upward (in the direction of arrow c) from the bent portion 12ba. 12bs, and a bent portion 12bc bent rightward (in the direction of arrow b) at the upper end (in the direction of arrow c) of the straight portion 12bs.

  The bent portion 12b is bent by the bent portion 12ba and the bent portion 12bc such that the base portion 12a and the connection surface 12m of the connection portion 12c are at different heights in the substrate vertical direction. Specifically, the bent portion 12ba and the bent portion 12ba of the bent portion 12 are arranged such that the connection surface 12m of the connection portion 12c and the exposed surface 3m of the insulating member 3 are at the same height position in the substrate vertical direction, that is, flush. The bent portion 12bc is bent.

  However, it is not always necessary that the connection surface 12m of the connection portion 12c and the exposed surface 3m of the insulating member 3 be completely at the same height position. It may have a recess slightly recessed from the projection, or may have a slightly convex protruding projection.

  Here, when the connection surface 12m of the connection portion 12c is slightly recessed from the exposed surface 3m of the insulating member 3, the depth of the recess is, for example, within 30 μm. The reason for setting the depth of the concave portion to 30 μm is that the depth is such that the variation in the amount of solder when applying the solder by using a metal mask MM (see FIG. 7) described later can be suppressed low.

  When the connection surface 12m of the connection portion 12c slightly protrudes from the surface 3m, the height of the protrusion is, for example, 100 μm to 200 μm, which is smaller than the thickness of a metal mask MM described later. The reason why the height of the protrusion is 100 μm to 200 μm is that the solder can be applied uniformly if the height of the protrusion is smaller than the thickness of the metal mask MM.

  That is, the height of the connection surface 12m of the connection portion 12c may be a height corresponding to the surface 3m of the insulating member 3, that is, within a range of −30 μm to 200 μm or less. However, more preferably, the connection surface 12m of the connection portion 12c and the exposed surface 3m of the insulating member 3 have the same height in the substrate vertical direction.

  The connecting portion 12c of the metal plate 12 is a portion that extends linearly from the bent portion 12bc of the bent portion 12b toward the right side (the direction of the arrow b), and the upper surface (in the direction of the arrow c) on which the electronic element 5 is mounted. And a connection surface 12m for electrical and mechanical connection. Therefore, when the electronic element 5 is placed and connected, the connection surface 12m of the connection part 12c on one side (left side) and the connection surface 12m of the connection part 12c on the other side (right side) are connected by one side. The (left) connection surface 12m and the other (right) connection surface 12m are mechanically and electrically connected.

  The left metal plate 12 and the right metal plate 12 are arranged so as to face each other via the opening 3h. Further, the left metal plate 12 and the right metal plate 12 are exposed in the opening 3h with a certain gap g provided so that the left and right connection portions 12c do not contact each other. The gap g is set in advance in accordance with the distance between one (left) electrode 5b and the other (right) electrode 5b in the electronic element 5.

  As shown in FIGS. 2A and 2B, the bending angle α of the straight portion 12bs with respect to the base 12a is defined via the bent portion 12ba, and the straight portion 12bs is formed via the bent portion 12bc. The bending angle β (β = 180 ° −α) of the connecting portion 12c is defined, and the bending state of the bent portion 12b is set by the bending angles α and β.

  For example, the bent portion 12b can bend the straight portion 12bs with respect to the base portion 12a at a bending angle α (= 90 °) or any bending angle α smaller than that. When the straight portion 12bs is bent at a bending angle α (= 90 °) with respect to the base portion 12a, the size of the gap g between one (left) connecting portion 12c and the other (right) connecting portion 12c is a maximum value. g1 and the height h from the base portion 12a to the connection portion 12c is the maximum value h1. In this case, as shown in FIG. 3A, the bent portion 12b of the metal plate 12 is bent at a right angle to the base 12a and the connecting portion 12c.

  In addition, the bent portion 12b can bend the straight portion 12bs with respect to the base 12a at a bending angle α (= 60 °). When the straight portion 12bs is bent at a bending angle α (= 60 °) with respect to the base 12a, the size of the gap g becomes a value g2 smaller than the maximum value g1, and the height from the base 12a to the connection portion 12c. The value h is also a value h2 smaller than the maximum value h1. In this case, as shown in FIG. 3B, the bent portion 12b of the metal plate 12 is bent at about 60 ° with respect to the base 12a.

  That is, the gap g between the one (left) metal plate 12 and the other (right) metal plate 12 and the height h from the base 12a to the connection portion 12c are determined by the bent portion 12b with respect to the base 12a. It can be set freely according to the bending angle α of the straight portion 12bs and the bending angle β of the connecting portion 12c with respect to the straight portion 12bs. Further, even when the bent portion 12b is bent at a bending angle α (= 90 °) with respect to the base 12a, the opening end face 3a of the opening 3h of the insulating member 3 and the straight portion 12bs of the metal plate 12 are formed. Is non-contact.

  As described above, the bent portion 12b of the metal plate 12 is bent into a substantially S shape including the bent portion 12ba, the straight portion 12bs, and the bent portion 12bc, and the opening end surface of the opening 3h of the insulating member 3 is formed. 3a. Therefore, since the movement of the bent portion 12b in the horizontal direction (the direction of the arrow ab) is not restricted, the solder 4 connecting the connection portion 12c of the metal plate 12 and the electronic element 5 is affected by the thermal stress. In this case, it functions as a stress relaxation portion that reduces the influence of thermal stress on the solder 4.

  Further, as shown in FIGS. 4A and 4B, when the bent portion 12b has a bending angle α (= 0 degree) with respect to the base portion 12a, that is, when the bent portion 12b is not bent, The length of the plate 12 is set as follows. The maximum protrusion amount Lmax from the opening end face 3a of the opening 3h of the insulating member 3 to the tip of the metal plate 12 is the length D / of the horizontal opening length D of the opening 3h from the opening end face 3a to the center C. 2 or less and is represented by the following equation 1.

Lmax ≦ D / 2 …………………………………… (Equation 1)

  This means that one (left) metal plate 12 and the other (right) metal plate 12 can be formed by cutting and bending one steel plate. That is, since it can be formed from one steel plate without the need for two steel plates, the structure can be reduced in cost.

  The metal plate 12 on one side (left side) and the metal plate 12 on the other side (right side) have an opening of the insulating member 3 when the bent portion 12b has a bending angle α (≧ 0 °) with respect to the base 12a. The protrusion amount L1 from the opening end surface 3a of 3h to the tip of the connection portion 12c is equal to or less than the maximum protrusion amount Lmax, and the gap g is equal to or greater than 0.

  Subsequently, as shown in FIG. 5 (A), in the connection portion 12c of the metal plate 12, the connection surface 12m electrically and mechanically connected to the electronic element 5 is slightly recessed from the connection surface 12m. A step surface 12d is formed. In this case, the connection surface 12m of the connection portion 12c and the exposed surface 3m of the insulating member 3 are at the same height position, but the step surface 12d is located below the surface 3m in the substrate vertical direction (the direction of the arrow cd). The height is slightly lowered in the direction of arrow d).

  The step surface 12d of the connection part 12c functions as a connection surface of the electronic element 5 and also functions as a surface on which the solder 4 is applied. The end of the connection portion 12c where the connection surface 12m is left functions as a weir that protrudes upward in the substrate vertical direction from the step surface 12d. The dam portion has a solder flow prevention structure for preventing an unexpected short circuit due to the flow of the solder 4 into the bent portion 12b when the wettability of the solder 4 is good.

  In this case, the step surface 12d of the connecting portion 12c is set at the same height position as the surface 3m of the insulating member 3, but is not limited to this, and the connecting surface 12m of the connecting portion 12c is It may be set at the same height position as the surface 3m. In this case, the step surface 12d is at a height position slightly recessed from the surface 3m of the insulating member 3.

  However, the solder flow prevention structure is not limited to this, and various other variations are conceivable. For example, as shown in FIG. 5B, a concave portion 12e having a predetermined depth may be provided at the left end of the connection surface 12m of the connection portion 12c as a solder flow prevention structure. The concave portion 12e functions as a storage portion of the solder 4 for preventing an unexpected short circuit due to the solder 4 flowing out to the bent portion 12b when the wettability of the solder 4 is good.

  As shown in FIG. 5C, a through hole 12f may be provided at the left end of the connection surface 12m of the connection portion 12c as a solder flow prevention structure. In this case, even if the wettability of the solder 4 is good, the solder 4 is a viscous liquid and is attached to the through hole 12f by the action of surface tension. Thus, the through-hole 12f functions as a path blocking portion of the solder 4 for preventing an unexpected short circuit due to the entire flow of the solder 4 to the bent portion 12b.

  As shown in FIG. 5D, an upwardly convex portion 12g may be provided between the bent portion 12b and the connection portion 12c as a solder flow prevention structure. The convex portion 12g functions as a weir portion for preventing an unexpected short circuit caused by the solder 4 flowing out to the bent portion 12b when the wettability of the solder 4 is good. The protruding portion 12g can be formed by bending the metal plate 12 with a press die.

  As shown in FIG. 5 (E), a concave protruding portion 12h may be provided on the lower side between the bent portion 12b and the connection portion 12c as a solder flow prevention structure. When the wettability of the solder 4 is good, the convex protruding portion 12h functions as a reservoir for the solder 4 for preventing an unexpected short circuit caused by the solder 4 flowing out to the bent portion 12b. . Note that the protruding protrusion 12g can be formed by bending the metal plate 12 with a press die.

  In the above configuration, the one (left side) and the other (right side) metal plates 12 of the electronic circuit board 10 each have a bent portion 12b functioning as a stress relaxation portion, as shown in FIG. I have. Thus, even when the one and other metal plates 12 and the electronic element 5 expand or contract to generate thermal stress, the bent portion 12b is bent as shown in FIG. 6B or 6C. Since it is possible to fall rightward or leftward through the portions 12ba and 12bc, the influence of thermal stress on the solder 4 can be absorbed.

  Thus, in the electronic circuit board 10, the influence of the thermal stress on the solder 4 can be reduced by the bent portions 12b of the one and the other metal plates 12, so that cracks are prevented from occurring in the solder 4. The mechanical and electrical connection between one and the other metal plate 12 and the electronic element 5 can be maintained.

  The electronic circuit board 10 is flush with the surface 3m of the insulating member 3 and the connection surface 12m of the connection portion 12c of the metal plate 12 with the same height. As a result, as shown in FIG. 7, with the metal mask MM placed on the surface 3m of the insulating member 3, the solder 4 is entirely applied to the surface of the metal mask MM, and the solder 4 is metallized with a squeegee SK. By filling the through holes of the mask MM, the solder 4 can be uniformly and collectively transferred to the connection surface 12m of the connection portion 12c of the metal plate 12. Therefore, when the height of the surface 3m of the insulating member 3 and the height of the connection surface 12m of the connection portion 12c of the metal plate 12 are not uniform, the manufacturing efficiency is much more remarkable than applying the solder 4 individually using a solder dispenser. Can be improved.

  Since the metal plate 12 includes the bent portion 12b including the bent portion 12ba, the straight portion 12bs, and the bent portion 12bc, the electronic element is positioned from the upper side (arrow c direction) in the substrate vertical direction (arrow cd direction). 5, the bent portion 12b has a rigidity that is not easily bent. Thus, the electronic circuit board 10 can maintain the height position between the surface 3m of the insulating member 3 and the connection surface 12m of the connection portion 12c of the metal plate 12. Thus, when applying the solder 4 to the connection surface 12m of the connection portion 12c via the metal mask MM and the squeegee SK, the electronic circuit board 10 prevents the transfer amount of the solder 4 from varying and transfers the solder 4 uniformly. be able to.

  Subsequently, as shown in FIG. 8A, the connecting portion 12c of the metal plate 12 on the lower electronic circuit board 10 and the connecting portion 12c of the metal plate 12 on the upper electronic circuit board 10 are in close contact with each other. The connection surfaces 12m of the connection portions 12c are reflowed with the solder 4 so that the connection portions 12c can be stacked in the direction perpendicular to the substrate (the direction of the arrow cd).

  In this case, since the connecting surface 12m of the connecting portion 12c and the surface 3m of the insulating member 3 are set to be flush with each other at the same height, the coating is performed between the lower connecting portion 12c and the upper connecting portion 12c. The amount of the solder 4 to be applied can be minimized. As described above, in the electronic circuit board 10, since the connection surface 12m of the connection portion 12c and the surface 3m of the insulating member 3 are set flush with each other at the same height, the thickness in the vertical direction of the board is minimized. The electronic circuit boards 10 can be stacked with excellent space efficiency.

  As shown in FIG. 8B, upper and lower electronic circuit boards 10s having a configuration in which respective connection portions 12cs of one (left) and the other (right) metal plates 12s are integrated, The connecting portion 12cs of the metal plate 12s in the lower electronic circuit board 10s and the connecting portion 12cs of the metal plate 12s in the upper electronic circuit board 10s are arranged in such a direction as to be in close contact with each other. Can be connected by solder 4.

  Further, as shown in FIG. 9, the connection portions 12c of the metal plate 12 on the lower electronic circuit board 10 and the connection portions 12c of the metal plate 12 on the upper electronic circuit board 10 are arranged in such a direction that they are in close contact with each other. In addition, a heat conductive sheet HCS made of, for example, silicone, acrylic, or the like can be sandwiched between the connection surfaces 12m of the connection portions 12c for connection. In this case, the thickness of the metal plate 12 may be reduced by the thickness of the heat conductive sheet HCS. Specifically, the thickness of the upper metal plate 12 and the thickness of the lower metal plate 12 may be set to be thinner by half the thickness of the heat conductive sheet HCS.

  In this case, the lower electronic circuit board 10 and the upper electronic circuit board 10 can be thermally connected via the heat conductive sheet HCS. Thereby, a heat radiation path is added so that heat generated in the lower electronic circuit board 10 and heat generated from the electronic element ep provided between the insulating members 3 are radiated from the upper electronic circuit board 10. Can be. As described above, since the connection surface 12m of the connection portion 12c and the surface 3m of the insulating member 3 are set at the same height, the lower electronic circuit board 10 and the upper electronic circuit board 10 are connected to each other by the heat conductive sheet. It is easy to thermally connect via the HCS, and it is possible to construct a form for efficiently dissipating heat.

  According to the above configuration, the influence of the thermal stress on the solder 4 can be alleviated by the bent portions 12b of the one and the other metal plates 12, and the occurrence of cracks in the solder 4 can be prevented in advance. An electronic circuit board 10 having high reliability without impairing the electrical and mechanical connection between the element 5 and the one and the other metal plates 12 can be realized.

<Second embodiment>
As shown in FIG. 10 in which the same reference numerals are given to portions corresponding to those in FIG. 1, in the electronic circuit board 20 in the second embodiment, the metal plate 12 of the electronic circuit board 10 in the first embodiment is different from the metal plate 12 in the first embodiment. It is characterized by having metal plates 22 of different shapes. In the second embodiment, the same components as those of the insulating member 3, the solder 4, and the electronic element 5 shown in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. .

  In the metal plate 22 of the electronic circuit board 20, the bent portion 22b is bent at bending angles α and β perpendicular to the base portion 22a and the connection portion 22c, and the bent portion 22b is formed on the opening end face 3a of the insulating member 3. In contact. The electronic circuit board 20 has the same configuration as the electronic circuit board 10 except for the metal plate 22.

  In this case, the bent portion 22b of the metal plate 22 is in contact with the open end surface 3a of the insulating member 3, but is not in a direction approaching each other in the horizontal direction of the substrate, so that the metal plates 22 are separated from each other. Only when the electronic element 5 contracts or the electronic element 5 contracts, the bent part 22b falls down so that the connection part 22c approaches each other along the horizontal direction of the substrate, and the influence of thermal stress on the solder 4 can be absorbed.

<Third embodiment>
As shown in FIG. 11 in which the same reference numerals are given to the portions corresponding to those in FIG. 1, in the electronic circuit board 30 in the third embodiment, the metal plate 12 of the electronic circuit board 10 in the first embodiment is different from the metal plate 12 in the first embodiment. It is characterized by having metal plates 32 of different shapes. In the third embodiment, the same components as those of the insulating member 3, the solder 4, and the electronic element 5 shown in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. .

  The metal plate 32 of the electronic circuit board 30 includes a base 32a, a bent portion 32b, and a connecting portion 32c. The base portion 32a is a portion that extends in the horizontal direction while being sandwiched between the upper insulating member 3 and the lower insulating member 3, and the tip thereof is exposed to the opening 3h of the insulating member 3.

  The bent part 32b is a part that connects the base part 32a and the connection part 32c. The bent portion 32b includes a bent portion 32ba bent at the tip of the base portion 32a, a straight line portion 32bs extending vertically from the bent portion 32ba upward (direction of arrow c), and an upper side of the straight portion (direction of arrow c). ) And a bent portion 32bc bent at the end.

  The bent portion 32b is bent at the two bent portions 32ba and 32bc such that the base 32a and the connection surface 32m of the connection portion 32c are at different heights in the substrate vertical direction. Specifically, the bent portion 32ba of the bent portion 32b is formed such that the connection surface 32m of the connection portion 32c and the exposed surface 3m of the insulating member 3 are at the same height position in the substrate vertical direction, that is, flush. 32bc is bent.

  However, the connecting surface 32m of the connecting portion 32c and the exposed surface 3m of the insulating member 3 do not necessarily have to be completely at the same height position. It may be slightly concave or slightly projecting.

  The connecting portion 32c is a portion that extends linearly from the bent portion 32bc of the bent portion 32b toward the insulating member 3, and the upper surface (in the direction of arrow c) of the bent portion 32b on which the electronic element 5 is placed is electrically connected. The connection surface 32m is to be connected mechanically and mechanically.

  In this case, the distal end of the metal plate 12 in the first embodiment is substantially S-shaped, whereas the distal end of the metal plate 32 in the third embodiment is substantially U-shaped. The functions of the plates 12 and 32 are the same. However, the electronic circuit board 30 in the third embodiment is not formed of two metal plates 32 from one steel plate, but formed of two metal plates 32 from two steel plates. However, the present invention is not limited to this, and two metal plates 32 may be formed from one steel plate when the interval between the bent portions 32b can be further increased.

<Fourth embodiment>
As shown in FIG. 12 in which the same reference numerals are given to the parts corresponding to FIG. 1, in the electronic circuit board 40 in the fourth embodiment, the metal plate 12 of the electronic circuit board 10 in the first embodiment It is characterized by having metal plates 42 of different shapes. Note that, in the fourth embodiment, the same components as those of the insulating member 3, the solder 4, and the electronic element 5 shown in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. .

  This electronic circuit board 40 includes a metal plate 42 arranged in a direction orthogonal to the metal plate 12 in the first embodiment. The metal plate 42 includes a base 42a, a bent portion 42b, and a connecting portion 42c.

  The base 42a is a portion extending in a direction orthogonal to the longitudinal direction of the insulating member 3 while being sandwiched between the upper insulating member 3 and the lower insulating member 3, and a part of the base 42a is 3h.

  The bent portion 42b is formed integrally with a part of the base 42a exposed to the opening 3h. The bent portion 42b is a portion that connects the base 42a and the connecting portion 42c. The bent portion 42b is bent at an end of the base portion 42a close to the insulating member 3, a bent portion 42ba, a straight line portion 42bs extending vertically from the bent portion 42ba upward (in the direction of arrow c), and the straight line 42bs. And a bent portion 42bc bent at the upper end (in the direction of arrow c) of the portion 42bs.

  The bent portion 42b is bent at the two bent portions 42ba and 42bc so that the base 42a and the connection surface 42m of the connection portion 42c are at different heights in the substrate vertical direction. Specifically, the bent portion 42b is bent so that the connecting surface 42m of the connecting portion 42c and the exposed surface 3m of the insulating member 3 are at the same height position in the substrate vertical direction, that is, flush with each other. 42bc.

  However, the connecting surface 42m of the connecting portion 42c and the exposed surface 3m of the insulating member 3 do not necessarily have to be completely at the same height position, and the connecting surface 42m of the connecting portion 42c is not necessarily the same as the exposed surface 3m of the insulating member 3. It may be slightly recessed from or slightly protruded.

  The connecting portion 42c is a portion extending linearly from the bent portion 42bc of the bent portion 42b toward the electronic element 5, and the upper surface (in the direction of arrow c) of the connecting portion 42c places the electronic element 5 thereon, and is electrically and mechanically mounted. A connection surface 42m is provided for the connection.

  As described above, the portion of the metal plate 42 where the base portion 42a, the bent portion 42b, and the connection portion 42c are formed is formed in a substantially U-shaped cross section. Also in this case, the bent portion 42b of the metal plate 42 falls down in the horizontal direction of the substrate, so that the influence of thermal stress on the solder 4 can be absorbed.

1, 10, 10s, 20, 30, 40 Electronic circuit board 2, 12, 22, 32, 42 Metal plate 3 Insulating member 3a Surface 3h Opening 4 Solder 5 Electronic element 5a Element body 5b Electrodes 12a, 22a, 32a, 42a Bases 12b, 32b, 42b Bends 12ba, 12bc Bends 12bs Straights 12c, 22c, 32c, 42c Connections 12d Step surfaces 12e Recesses 12f Through holes 12g Convexes 12h Concave protrusions 2m, 12m, 22m, 32m, 42m Connection surface g Gap h Height L1 Projection amount Lmax Maximum projection amount D Opening length ep Electronic element HCS Thermal conductive sheet MM Metal mask SK Squeegee

Claims (7)

A metal plate forming a circuit conductor;
An electronic circuit board comprising: an insulating member molded while sandwiching the metal plate;
The insulating member has an opening where no insulating member is present in a part thereof,
The metal plate has one and the other bases respectively sandwiched by the insulating members in a state where the metal plates face each other with the opening interposed therebetween, and has a connection surface for electrically connecting to an electronic element. One and the other connection portions respectively exposed to the opening so that the connection surfaces face each other with the opening interposed therebetween so as not to contact each other, and a height position where the connection portion is different from the base portion. become as the metal plate is bent in the base and the said connecting portion possess the one and the other bent portion respectively link,
The connection surface is set at a height corresponding to the surface of the insulating member according to a bent state of the bent portion,
The electronic circuit board , wherein the bent portion is not in contact with the insulating member . Said connection unit, an electronic circuit board according to claim 1 Symbol mounting and having an outflow preventing structure for preventing the solder from flowing out to the bent portion to the connection surface. The one connection surface is connected to one electrode of the electronic element, the other connection surface is connected to the other electrode of the electronic element, and the one connection surface is connected to the other connection surface. electronic circuit board according to claim 1 or 2 faces and is characterized in that it is mechanically and electrically connected by the electronic device. The insulating member is, when it is stacked with other electronic circuit board of the insulating member, an electronic circuit board according to any one of claims 1 to 3, characterized in that the connecting faces are connected to each other. The electronic circuit board according to claim 4 , wherein the connection portions are electrically connected to each other via solder between the connection surfaces. The electronic circuit board according to claim 4 , wherein the connection portions are thermally connected to each other between the connection surfaces via a heat conductive sheet. The bent portion is a portion in which a part of the base of the metal plate that protrudes from the insulating member to the opening so as to face each other is cut and bent, and the protruding amount of the portion with respect to the opening is The electronic circuit board according to any one of claims 1 to 6 , wherein the length is not more than half the length of the opening along the longitudinal direction of the metal plate.

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