JP2003152369A - Radiation structure of electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the small amount of stress in solder at a substrate and a lead section and a sufficient radiation effect. SOLUTION: In the radiation structure of an electronic component, a plurality of lead sections 2 of an electronic component 1 are connected to a substrate 3 that is accommodated in a case body 5 by a solder section, and the rear of the electronic component 1 is brought into contact with and at the same time is adhered to the case body 5 by a mounting spring 4 for radiation. In this case, when the electronic component 1 is packaged to the substrate 3, the shape of one of a plurality of component insertion holes 8 on the substrate 3 where the plurality of lead sections 2 are inserted is changed. For example, the play of one of the component insertion holes 8 is set larger than that of the other of the insertion holes 8. As a result, upstanding properties in the component itself are maintained, and coherency with the case body 5 can be increased, thus reducing the stress of solder to the substrate 3 and lead section 2, and at the same time obtaining a sufficient heat effect when radiating the heat of the electronic component 1 to the peripheral case body 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat radiating structure for electronic parts, which can radiate electronic parts and the like to a surrounding case.

[0002]

2. Description of the Related Art As the power level of semiconductor devices increases and the density of parts increases, more efficient heat dissipation design is required. Generally, when the junction temperature rises in semiconductor devices used for electronic application related equipment,
The function, performance and reliability may be deteriorated and eventually destroyed.

Therefore, it is necessary to lower the junction temperature of the semiconductor to a safe operating temperature range specified by the semiconductor manufacturer. Therefore, heat radiation is usually performed using a heat sink, which is the most practical and economical component for cooling a semiconductor.

Similar to other electronic application devices, there is a strong demand for light, thin, short, and small discharge lamp lighting devices. As a result, the internal temperature of the lighting device rises, the temperature of the electronic parts used, etc. rises, and the life and There was a problem that the reliability was adversely affected.

As a countermeasure, there is a method of radiating heat of a high temperature component such as a transistor using the above heat sink, but as shown in FIG. 11 and FIG.
Using the mounting spring 4, a metal case lid or case body 5
There is also a method of closely fixing and radiating heat, and the methods shown in FIGS. 11 and 12 are effective from the viewpoint of reducing the number of parts and cost. In the figure, 1 is a semiconductor component, 2 is a semiconductor component 1
2 is a printed circuit board, 6 is a solder part, 7 is a case claw, and 8 is an insertion port (component insertion hole) of the lead part 2.

[0006]

However, such a conventional example has the following problems. That is, in the case where the semiconductor component 1 is mounted on the substrate 3 by hand in a manufacturing line and is poured into a solder bath, the substrate 3 is usually used.
Since the shape of the component insertion hole 8 is set to be slightly larger than the cross-sectional area shape of the component lead portion 2, the semiconductor component 1 is gradually
May tilt. Therefore, when the printed circuit board 3 is housed in the case body 5 and fixed by the mounting spring 4 in the final step, a gap 25 is formed between the rear surface of the semiconductor component 1 and the case body 5 as shown in FIG. The heat dissipation effect is impaired, the heat loss increases, and the input power to the lighting device increases.
There was a problem that the amount of heat generated by electronic components increased.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a heat dissipation structure for an electronic component in which the stress of the solder on the substrate and the lead portion is small and a sufficient heat dissipation effect can be obtained.

[0008]

In order to solve the above-mentioned problems, the heat dissipation structure for an electronic component according to claim 1 of the present invention is such that a plurality of lead parts of the electronic component are connected to a substrate housed in a case body by a solder part. In the heat dissipation structure of the electronic component, the back surface of the electronic component and the case body are attached to each other by using a mounting spring, and when the electronic component is mounted on the substrate, the plurality of lead portions are provided. The shape of any of the plurality of component insertion holes of the board to be inserted was changed.

As described above, when the electronic component is mounted on the substrate, any one of the plurality of component insertion holes of the substrate into which the plurality of lead portions is inserted is changed. By making the play of smaller than other insertion holes,
The uprightness of the parts themselves can be maintained and the close contact with the case body can be enhanced. As a result, when the electronic component is radiated to the surrounding case body, the stress of the solder on the substrate and the lead portion can be reduced, and a sufficient heat radiation effect can be obtained.

According to a second aspect of the invention, there is provided a heat dissipation structure for an electronic component according to the first aspect, in which one of the lead parts of the electronic component is processed to change its shape. In this way, by processing one of the lead parts of the electronic component to change its shape, the inclination of the component when flowing into the solder bath is suppressed,
The uprightness of electronic components can be maintained.

According to a third aspect of the present invention, there is provided a heat dissipation structure for an electronic component according to the first aspect, wherein an elastic metal is used in a portion of the case body which is in contact with the electronic component. Since the metal having elasticity is used for the portion of the case body that is in contact with the electronic component as described above, the adhesion between the electronic component and the metal portion made of the metal having elasticity can be improved. That is, even when the electronic component is mounted in an inclined manner when the electronic component moves in the solder bath, it is possible to maintain adhesion by bending the metal part according to the inclination,
It is possible to prevent an increase in heat loss.

According to a fourth aspect of the present invention, there is provided a heat dissipation structure for an electronic component according to the first aspect, wherein the electronic part has three lead portions, and the electronic part is mounted on a board to face the electronic part. When defining the shapes of the center part insertion hole and the remaining two part insertion holes, when the part insertion hole is square,
The length in the longitudinal direction of the component insertion hole in the central portion is L1, the length in the lateral direction is L3, the length in the longitudinal direction of the remaining two component insertion holes is L2, and the length in the lateral direction is L4. When the part insertion hole is round, the diameter of the part insertion hole in the center is φ1 and the remaining 2
Assuming that the diameter of one component insertion hole is φ2, in the rectangular shape, 0 <(L2-L1) ≦ 0.1,0 <(L
4-L3) ≦ 0.1 In the round shape, the component insertion hole was set so that 0 <(φ2-φ1) ≦ 0.1.

Thus, in the rectangular shape, 0 <(L2-
L1) ≤ 0.1, 0 <(L4-L3) ≤ 0.1, and in the round shape, the component insertion holes were set so that 0 <(φ2-φ1) ≤ 0.1, so the electronic component center It is effective to maintain the uprightness of the electronic component by making the play of the component insertion hole of the board smaller than that of the other insertion holes in the above range with respect to the lead portion of the electronic component.

According to a fifth aspect of the present invention, there is provided an electronic component heat radiation structure according to the first aspect, wherein the electronic component has three lead portions, and the electronic component is mounted on a substrate and is in front of the electronic component. When defining the shapes of the center part insertion hole and the remaining two part insertion holes, when the part insertion hole is square,
The length in the longitudinal direction of the component insertion hole in the central portion is L1, the length in the lateral direction is L3, the length in the longitudinal direction of the remaining two component insertion holes is L2, and the length in the lateral direction is L4. When the part insertion hole is round, the diameter of the part insertion hole in the center is φ1 and the remaining 2
Assuming that the diameter of one component insertion hole is φ2, in the rectangular shape, 0 <(L1-L2) ≦ 0.1,0 <(L
3-L4) ≦ 0.1 In the round shape, the component insertion holes were set so that 0 <(φ1−φ2) ≦ 0.1.

Thus, in the rectangular shape, 0 <(L1-
L2) ≦ 0.1, 0 <(L3-L4) ≦ 0.1, and in the round shape, the component insertion holes are set to satisfy 0 <(φ1-φ2) ≦ 0.1. It is effective to maintain the uprightness of the electronic component by making the play of the component insertion hole of the board smaller than that of the insertion hole of the central portion with respect to the lead portion other than the central portion within the above range.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described with reference to FIG. 1 is a perspective view of a heat dissipation structure for an electronic component according to a first embodiment of the present invention. The purpose of this embodiment is to maintain the uprightness of the parts themselves and to improve the close contact with the case body.

As shown in FIG. 1, a plurality of lead portions 2 of an electronic component 1 such as a semiconductor component are connected to a printed circuit board 3 housed in a case body 5, and the back surface of the electronic component 1 and the case body 5 are connected.
Are attached to and in close contact with each other to dissipate heat. The printed circuit board 3 is supported by the case claws 7 and connected to the lead portions 2 of the electronic component 1 by the solder portions 6 as in the case of FIG. The electronic component 1 has three lead portions 2. In such a configuration, when the electronic component 1 is mounted on the printed circuit board 3, one of the plurality of component insertion holes 8 of the printed circuit board 3 into which the plurality of lead portions 2 are inserted is changed. In this case, at least one of the plurality of component insertion holes 8 of the printed circuit board 3 has a play portion extremely small so that the component can be firmly fixed.

As a method, there are three lead portions 2a,
2b, 2c, a method of making the play of the component insertion hole 8 of the printed circuit board 3 smaller than that of the other insertion hole 8 with respect to the lead portion 2b in the central portion of the semiconductor component 1,
There is a method of reducing the component insertion hole 8 of the printed circuit board 3 with respect to 2b, but the uprightness of the component can be maintained by any method.

In the former method, when the shapes of the component insertion hole 8 and the remaining two component insertion holes 8 in the central portion of the front surface of the electronic component 1 are determined with the electronic component 1 mounted on the printed circuit board 3, the component insertion hole 8 is formed. When the is square, the part insertion hole 8 in the center
Let L1 be the length in the lengthwise direction, L3 be the length in the widthwise direction, L2 be the length in the lengthwise direction of the remaining two component insertion holes 8, and L4 be the length in the widthwise direction. In the case of a round shape, assuming that the diameter of the central component insertion hole 8 is φ1 and the diameters of the remaining two component insertion holes 8 are φ2, in the rectangular shape, 0 <(L2-L1) ≦ 0.1,0 < (L
4-L3) ≦ 0.1 In the round shape, the component insertion hole 8 was set so that 0 <(φ2-φ1) ≦ 0.1.

In the latter method, when the shapes of the component insertion hole 8 and the remaining two component insertion holes 8 in the central portion of the front surface of the electronic component 1 are determined in a state where the electronic component 1 is mounted on the printed circuit board 3, in the rectangular shape, 0 <(L1-L2) ≦ 0.1, 0 <(L
3-L4) ≦ 0.1 In the round shape, the component insertion hole 8 was set so that 0 <(φ1−φ2) ≦ 0.1.

As described above, according to this embodiment, when the electronic component 1 is mounted on the printed circuit board 3, any of the plurality of component insertion holes 8 of the printed circuit board 3 into which the plurality of lead portions 2 are inserted. Since the shape is changed, for example, by making the play of one of the component insertion holes 8 smaller than that of the other insertion holes 8, the uprightness of the component itself can be maintained and the close contact with the case body 5 can be enhanced. As a result, when the electronic component 1 is radiated to the surrounding case body 5, the stress of the solder on the printed circuit board 3 and the lead portion 2 can be reduced, and a sufficient heat radiation effect can be obtained.

A second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a perspective view of a heat dissipation structure for electronic parts according to a second embodiment of the present invention. In this embodiment, the uprightness of the component is maintained by processing the lead portion.

As shown in FIG. 2, one of the lead portions 2 of the electronic component 1 was processed to change its shape. First, in an electronic component having a lead portion 2 having a rectangular cross section, an angle θ formed by the longitudinal direction B of the rectangular cross section of the lead portions 2a and 2c other than the central portion of the electronic component 1 and the longitudinal direction A of the printed board 3. Is arbitrarily set within an angle range of 0 ° <θ <180 °. If the angle θ between the substrate longitudinal direction A and the longitudinal direction B of the lead portion 2 is 0 ° as in the conventional example, the electronic component 1 is naturally used.
Is easily tilted in the direction of arrow D due to the influence of stress and the existence of a play portion of the component insertion hole 8 provided in the printed circuit board 3.

In the case of this embodiment, when the electronic component 1 is manufactured, the lead portions 2a and 2c are previously set to a certain angle θ with respect to the substrate longitudinal direction A as shown in FIG.
The lead structure is set so as to maintain (0 ° <θ <180 °). (In the case of θ = 90 ° in FIG. 2) With such a lead structure, the inclination of the component in the arrow D direction can be reduced. Further, by setting the longitudinal direction B of the rectangular cross section of the lead portion 2b at the central part of the electronic component 1 to be the longitudinal direction A, the inclination in the arrow C direction can be reduced. The shape (direction) of the component insertion hole 8 is changed so that the lead portions 2a and 2c can be inserted. As a result, it becomes possible to maintain the uprightness of the parts as in the first embodiment. Other configuration effects are similar to those of the first embodiment.

A third embodiment of the present invention will be described with reference to FIG. FIG. 3 is a perspective view of a heat dissipation structure for electronic parts according to a third embodiment of the present invention.

As shown in FIG. 3, in an electronic component 1 having a lead portion 2 having a square cross section, the lead portions 2a and 2c other than the central portion of the electronic component 1 have a rectangular parallelepiped structure having a square cross section S1. Cross section S1 of the lead portions 2a, 2c of
The angle between the diagonal direction E and the longitudinal direction A of the printed circuit board 3 is 90 °. In addition, the lead portion 2 in the center of the electronic component 1
The longitudinal direction B of the rectangular cross section of b is the longitudinal direction A.
The shape of the component insertion hole 8 is changed so that the lead portions 2a and 2c can be inserted. As a result, the inclination in the arrow C direction and the arrow D direction can be reduced, and the uprightness of the component can be maintained.
Other configuration effects are similar to those of the first embodiment.

A fourth embodiment of the present invention will be described with reference to FIG. FIG. 4 is a perspective view of an electronic component according to a fourth embodiment of this invention.

As shown in FIG. 4, in the forming shape of the lead portion 2 of the electronic component 1, by forming the lead portions 2a and 2c other than the central portion of the electronic component 1 before and after the central lead portion 2b, printing is performed. It has a component structure that suppresses the inclination of the component when it is mounted on the substrate 3. in this case,
In the forming of the lead portions 2a and 2c other than the central portion of the electronic component 1 with respect to the front direction in which the lead portion 2 of the component is arranged downward, the upper portion of one lead portion 2c is in the front horizontal direction and the lower portion is downward. The other lead portion 2a is bent in the inner side horizontal direction, and the lower part is bent in the lower side vertical direction. The shape (arrangement) of the component insertion hole 8 is changed so that the lead portions 2a and 2c can be inserted. Even with this structure, the uprightness of the printed circuit board 3 can be maintained as compared with the conventional forming shape of electronic components. Other configuration effects are similar to those of the first embodiment.

A fifth embodiment of the present invention will be described with reference to FIG. FIG. 5 is a perspective view of a heat dissipation structure for electronic parts according to a fifth embodiment of the present invention. In this embodiment, the basic idea of maintaining the uprightness of the components is the same as in the first to fourth embodiments, but the difference from these is that the lead portion of the electronic component is not processed. Connector to the lead part.

As shown in FIG. 5, the lead portions 2a and 2c other than the central portion of the electronic component 1 are provided with the connector 9 having a square cross section for preventing inclination, so that the electronic component 1 can be moved in the directions of arrows C and D. Reduce tilt. The insertion angle of the connector 9 is preferably 90 ° in the diagonal direction E of the cross section S1 of the square connector 9 with respect to the longitudinal direction A of the printed circuit board 3. The shape of the component insertion hole 8 is changed so that the lead portions 2a and 2c can be inserted together with the connector 9.

A sixth embodiment of the present invention will be described with reference to FIGS. 6 and 7. FIG. 6 is a perspective view of a heat dissipation structure for an electronic component according to a sixth embodiment of the present invention, and FIG. 7 is an operation explanatory view of the sixth embodiment. The purpose of this embodiment is to improve the adhesiveness between the electronic component and the metal portion by using the elastic metal portion for the case heat dissipation portion even when the electronic component is tilted.

As shown in FIG. 6, in the metal case body 5 that contacts the electronic component 1, at least one or more elastic heat radiating metal portions 5 ′ are in contact with the back surface of the electronic component 1. Is provided. The metal part 5 ′ is formed by cutting the metal body case 5 with the notch 15. Further, as shown in FIG. 7, the metal portion 5 ′ may have a bent portion 16. Although the configuration of the lead portion 2 and the component insertion hole 8 of the electronic component 1 is illustrated as being similar to that of the first embodiment, it may be configured as in the second to fifth embodiments.
Further, the mounting spring 4 is used for mounting the electronic component 1, and the printed circuit board 3 is supported by the case claw 7 as in the first embodiment.

When the electronic component 1 manually mounted on the manufacturing line is tilted when moving in the solder bath, the conventional example when the printed circuit board 3 is housed in the case body 5 is shown in FIG. In addition, a gap is created between the back surface of the electronic component 1 and the case body 5, and the heat dissipation effect is impaired. On the other hand, according to this embodiment, even when the electronic component 1 is mounted by being inclined by the elastic metal portion 5 ', as shown in FIG. By appropriately bending in the direction, it becomes possible to maintain the adhesion between the electronic component 1 and the metal part 5 ′, and it is possible to prevent an increase in heat loss. Other configuration effects are similar to those of the first embodiment.

A seventh embodiment of the present invention will be described with reference to FIG. FIG. 8 is a side view of a heat dissipation structure for electronic parts according to a seventh embodiment of the present invention.

As shown in FIG. 8, a metal case body 5 using a metal having elasticity in a portion in contact with the electronic component 1.
In the electronic component 1, the side surface shape of the case body 5 near the lead portion of the electronic component 1 is stepped like the stepped portion 10 to maintain the insulation distance between the lead portion 2 and the case body 5 in the immediate vicinity thereof. The contact area of the contact portion between the back surface of the component 1 and the case body 5 can be increased.

Since the uprightness of the parts is also very important in this structure, it goes without saying that the structure is combined with any of the methods described in the first to fifth embodiments. FIG. 8 shows a case of combining with the measure of FIG. Further, the mounting spring 4 is used for mounting the electronic component 1, and the printed circuit board 3 is supported by the case claw 7 as in the first embodiment.

The eighth embodiment of the present invention will be described with reference to FIG. FIG. 9 is a plan view of a heat dissipation structure for electronic parts according to an eighth embodiment of the present invention. In this embodiment,
The purpose is to increase the surface area of the case body and improve heat dissipation.

As shown in FIG. 9, the metal case body 5 is made of a metal having elasticity in a portion in contact with the electronic component 1.
In, the heat dissipation effect is improved by providing at least one groove 11 on the side surface of the case body 5 to increase the surface area. Thereby, the heat dissipation of the case body 5 can be improved. The configurations of the lead portion 2 and the component insertion hole of the electronic component 1 can apply the first to fifth embodiments. Further, the mounting spring 4 is used for mounting the electronic component 1, and the printed circuit board is supported by the case claws as in the first embodiment.

The ninth embodiment of the present invention will be described with reference to FIG. FIG. 10 is a circuit diagram of the ninth embodiment of the present invention.

The heat dissipation structure according to the first to eighth embodiments is, for example, a power supply voltage rectifying circuit 20, a power supply circuit 21, and at least one of the electronic application related devices requiring heat dissipation as shown in FIG. It can be applied to the switch element 23 of the discharge lamp lighting circuit configured by the inverter circuit 22 having the switch element 23 described above. The electronic component 1 by combining and adapting the first to eighth embodiments
The adhesion between the case body 5 and the case body 5, the uprightness of the electronic components, and the heat dissipation effect of the case body itself are enhanced, and the heat dissipation performance of the semiconductor element of the lighting inverter circuit can be improved as compared with the conventional case.

[0041]

According to the heat dissipation structure of the electronic component of the present invention, any of the plurality of component insertion holes of the substrate into which the plurality of lead portions are inserted when the electronic component is mounted on the substrate. Since the shape is changed, for example, by making the play of one of the component insertion holes smaller than that of the other insertion holes, the uprightness of the component itself can be maintained and the close contact with the case body can be enhanced. This reduces the stress of solder on the board and leads when radiating electronic components to the surrounding case body, improving their reliability and enhancing their adhesion and uprightness of components, thus improving the heat radiation effect. Can be made.

According to the second aspect of the present invention, by processing one of the lead parts of the electronic component to change its shape, the inclination of the component when it is poured into the solder bath can be suppressed and the uprightness of the electronic component can be maintained.

According to the third aspect, since the elastic metal is used for the portion of the case body that comes into contact with the electronic component, the adhesion between the electronic component and the metal portion made of the elastic metal can be enhanced. In other words, even when the electronic components are mounted in an inclined manner when the electronic components move in the solder bath, it is possible to maintain the adhesiveness by bending the metal part according to the inclination, which increases heat loss. Can be prevented.

In the fourth aspect, in the rectangular shape, 0 <(L2
-L1) ≤ 0.1, 0 <(L4-L3) ≤ 0.1, and in the round shape, the component insertion holes were set to satisfy 0 <(φ2-φ1) ≤ 0.1. It is effective to maintain the uprightness of the electronic component by making the play of the component insertion hole of the board smaller than that of the other insertion holes with respect to the central lead portion within the above range.

In the fifth aspect, in the rectangular shape, 0 <(L1
-L2) ≤ 0.1, 0 <(L3-L4) ≤ 0.1, and in the round shape, the component insertion holes were set to satisfy 0 <(φ1-φ2) ≤ 0.1. It is effective to maintain the uprightness of the electronic component by making the play of the component insertion hole of the board smaller than that of the insertion hole of the central portion with respect to the lead portion other than the central portion in the above range.

[Brief description of drawings]

FIG. 1 is a perspective view of a heat dissipation structure of an electronic component according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a heat dissipation structure for electronic parts according to a second embodiment of the present invention.

FIG. 3 is a perspective view of a heat dissipation structure of an electronic component according to a third embodiment of the present invention.

FIG. 4 is a perspective view of an electronic component according to a fourth embodiment of the present invention.

FIG. 5 is a perspective view of a heat dissipation structure of an electronic component according to a fifth embodiment of the present invention.

FIG. 6 is a perspective view of a heat dissipation structure for electronic parts according to a sixth embodiment of the present invention.

FIG. 7 is an operation explanatory view of the sixth embodiment.

FIG. 8 is a side view of a heat dissipation structure of an electronic component according to a seventh embodiment of the present invention.

FIG. 9 is a plan view of a heat dissipation structure of an electronic component according to an eighth embodiment of the present invention.

FIG. 10 is a circuit diagram of a ninth embodiment of the present invention.

FIG. 11 is a perspective view of a conventional heat dissipation structure for an electronic component.

FIG. 12 is an explanatory diagram of a problem of the conventional example.

[Explanation of symbols]

1 electronic components 2 lead part 3 printed circuit boards 4 mounting spring 5 Case body 5'metal part 6 Solder part 7 case claws 8 parts insertion holes A printed circuit board longitudinal direction B Lead longitudinal direction Vertical direction with C B Horizontal direction with DB

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroyuki Asano             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works             Within the corporation (72) Inventor Masahiro Yamanaka             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works             Within the corporation F-term (reference) 5E322 AA03 AB04                 5E336 AA04 BB02 BC07 CC03 CC51                       GG05

Claims (5)

[Claims] 1. An electronic component in which a plurality of lead portions of the electronic component are connected to a substrate housed in a case body by a solder portion, and the back surface of the electronic component and the case body are brought into contact and close contact with each other using a mounting spring to radiate heat. In the heat dissipation structure according to claim 1, when mounting the electronic component on the substrate, any one of a plurality of component insertion holes of the substrate into which the lead portions are inserted is changed. Heat dissipation structure. 2. The heat dissipation structure for an electronic component according to claim 1, wherein one of the lead parts of the electronic component is processed to change its shape. 3. The heat dissipation structure for an electronic component according to claim 1, wherein a metal having elasticity is used for a portion of the case body that comes into contact with the electronic component. 4. The electronic component has three lead parts, and when the shapes of the component insertion hole and the remaining two component insertion holes in the front central portion of the electronic component are determined in a state where the electronic component is mounted on a substrate,
When the component insertion holes are square, the length of the central component insertion hole in the longitudinal direction is L1, the length in the lateral direction is L3, and the length of the remaining two component insertion holes in the longitudinal direction is L2, the lateral direction. When the component insertion hole is round, the diameter of the central component insertion hole is φ1, and the diameters of the remaining two component insertion holes are φ2.
Then, in the rectangular shape, 0 <(L2-L1) ≦ 0.1,0 <(L
4-L3) ≦ 0.1 The heat dissipation structure for electronic parts according to claim 1, wherein the parts insertion holes are set so that 0 <(φ2-φ1) ≦ 0.1 in a round shape. 5. The electronic component has three lead portions, and when the shapes of the component insertion hole and the remaining two component insertion holes at the center of the front surface of the electronic component are determined with the electronic component mounted on the substrate,
When the component insertion holes are square, the length of the central component insertion hole in the longitudinal direction is L1, the length in the lateral direction is L3, and the length of the remaining two component insertion holes in the longitudinal direction is L2, the lateral direction. When the component insertion hole is round, the diameter of the central component insertion hole is φ1, and the diameters of the remaining two component insertion holes are φ2.
Then, in the rectangular shape, 0 <(L1-L2) ≦ 0.1,0 <(L
3-L4) ≦ 0.1 The heat dissipation structure for an electronic component according to claim 1, wherein the component insertion hole is set so that 0 <(φ1−φ2) ≦ 0.1 in a round shape.