JP2011060889A - Package with electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a package with an electronic component which realizes miniaturization and enhances the operation reliability of the electronic component. <P>SOLUTION: A body 6, which is a resin, expands thermally due to change in the open-air temperature (temperature increase, to be precise). Since the resin material has a thermal expansion coefficient higher than that of a metal, etc., the body 6 shows a large thermal distortion caused by thermal expansion. The thermal expansion of the body 6 applies an external force to a lead frame 8 fixed to the body 6. In response to this external force, an easing portion 11 formed on an electronic component 10a of the lead frame 8 deforms elastically, which prevents the external force from propagating to the electronic component 10a. This suppresses the occurrence of trouble of the electronic component 10a, thus enhance the operation reliability of the electronic component 10a. Such a configuration allows dispensing with a printed board, thus realizing miniaturization of a current sensor, at the same time. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a package with electronic components.

  Conventionally, for example, as shown in Patent Document 1, electronic components such as an amplifier circuit and a noise filter are arranged on a printed board including a lead frame and then packaged with a resin material. The thermal expansion coefficient of the printed circuit board is adjusted by appropriate selection of the material or the like so that an external force that leads to a malfunction of the electronic component is not applied due to thermal stress and thermal expansion caused by changes in the outside air temperature.

  By the way, in recent years, with a demand for miniaturization of various products, a more compact package with electronic components is required. Therefore, a package with an electronic component in which a printed board is omitted has been studied. Specifically, as shown in FIG. 8, a lead frame 108 made of a conductive material is fitted on the inner bottom surface of a body 106 made of resin. Here, the lead frame 108 has the same surface as the inner bottom surface of the body 106. The electronic component 110 is installed on the inner bottom surface of the body 106 at a position in contact with the lead frame 108. Thereby, the electronic component 110 is electrically connected by the lead frame 108. According to this configuration, since a printed circuit board is not required, a more compact package with electronic components can be constructed.

JP-A-9-32145

  By the way, in the package with an electronic component in which the printed circuit board described above is omitted, the body 106 is made of resin, and the influence of thermal expansion due to an increase in the outside air temperature is higher than that of the printed circuit board with the adjusted thermal expansion coefficient. Big. This is because the body 106 mainly functions as a case for protecting the electronic component 110 from the outside, and is not considered from the viewpoint of physical properties such as a coefficient of thermal expansion. Due to this thermal expansion, an external force is applied to the electronic component 110 directly or via the lead frame 108. In addition, an external force is similarly applied to the electronic component 110 even during heat shrinkage accompanying a decrease in the outside air temperature. Since thermal expansion and contraction occur with a temperature difference, for example, when installed in an environment where the change in ambient temperature is large, external force is repeatedly generated on the electronic component 110 semipermanently. Thereby, there is a concern that the electronic component 110 may be defective.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a package with an electronic component in which the reliability of the operation of the electronic component is enhanced while realizing miniaturization.

Hereinafter, means for achieving the above-described object and its operation and effects will be described.
According to a first aspect of the present invention, there is provided a package with an electronic component in which a cover is attached to a body made of a resin to which a lead frame for energizing the electronic component is fixed, and the lead frame and the electronic component are packaged. In the meantime, a relaxation portion for separating the electronic component from the body is provided, and the relaxation portion is formed by a conductive material so as to be elastically deformable.

  According to this configuration, the body, which is a resin, thermally expands due to a change in the outside air temperature (more precisely, a temperature increase). Here, since the thermal expansion coefficient of the resin material is higher than that of metal or the like, the thermal strain due to the thermal expansion of the body is large. External force is applied to the lead frame fixed to the body by thermal expansion of the body. When the relaxation portion interposed between the lead frame and the electronic component is elastically deformed against the external force, the external force is suppressed from being transmitted to the electronic component. As a result, the occurrence of defects in the electronic component is suppressed, and as a result, the reliability of the operation of the electronic component is enhanced. Moreover, according to the said structure, since a printed circuit board can be abbreviate | omitted, size reduction of a package with an electronic component is realizable.

  According to a second aspect of the present invention, in the package with an electronic component according to the first aspect, the relaxation portion is formed by bending a part of the lead frame to the side opposite to the inner bottom surface of the body. This is the gist.

  According to this configuration, the relaxation portion is formed by bending a part of the lead frame. Therefore, it is not necessary to newly form the relaxation portion as a separate member, and the reliability of the operation of the electronic component can be enhanced without increasing the number of components constituting the package with the electronic component.

  According to a third aspect of the present invention, in the package with an electronic component according to the first or second aspect, an installation portion on which the electronic component is installed at an end of the relaxation portion on the opposite side of the body is the body. Its gist is that it is formed parallel to the inner bottom surface.

  According to this configuration, the electronic component can be more stably held from the lead frame through the relaxation portion by installing the electronic component in the installation portion.

  ADVANTAGE OF THE INVENTION According to this invention, in the package with an electronic component, reliability of operation | movement of an electronic component can be improved, implement | achieving size reduction.

The disassembled perspective view of the current sensor in this embodiment. The perspective view of the lead frame built in the body in this embodiment. AA line sectional view of Drawing 2 in this embodiment. AA line sectional view of Drawing 2 before press processing in this embodiment. (A) in this embodiment is a perspective view of the electricity supply line by which the front-end | tip was extended, (b) is a perspective view of the electricity supply line by which the front-end | tip was bent. FIG. 3 is a cross-sectional view taken along the line AA of FIG. 2 after mounting in the present embodiment and before mounting an electronic component. The perspective view of the connection member attached to the lead frame in other embodiments. Sectional drawing of the package with the conventional electronic component. Sectional drawing of the package with an electronic component in other embodiment.

Hereinafter, an embodiment in which a package with electronic components according to the present invention is embodied in a current sensor 1 will be described with reference to FIGS.
As shown in FIG. 1, the current sensor 1 is configured by housing various electronic components 10 a to 10 c provided on a lead frame 8 made of a conductive metal material in a resin package (housing). Here, the package includes a cover 5 and a body 6.

  FIG. 2 shows a state where the electronic components 10 a to 10 c are mounted on the lead frame 8. The electronic components 10a to 10c are, for example, an amplifier circuit, a Hall IC, and a noise filter, respectively. The current sensor 1 detects the value of the current flowing through the detection target by detecting a change in the magnetic field generated according to the current flowing through the current path that is the detection target by the electronic component 10b that is the Hall IC. An electronic component 10a that is an amplifier circuit and an electronic component 10c that is a noise filter are provided to optimize the detection result of the Hall IC. The optimized detection result is output to the outside through the lead terminal 4 protruding to the outside of the current sensor 1.

  As shown in FIG. 2, a lead frame 8 is fixed to the inner bottom surface of the body 6. The lead frame 8 is formed thin so as to facilitate bending. In addition, the lead frame 8 includes a current line 9 having a predetermined width that is stretched around the inner bottom surface of the body 6. A part of the energization line 9 projects outside the body 6, and this projecting part functions as the lead terminal 4 described above. The energization line 9 electrically connects the electronic components 10 a to 10 c arranged at various locations of the lead frame 8, and sends signals from the electronic components 10 a to 10 c to the outside of the current sensor 1 via the lead terminals 4. Or output to

  As shown in FIG. 3, the body 6 is formed in a U-shaped cross section that opens upward. FIG. 3 shows only the electronic component 10a. The cover 5 indicated by the alternate long and short dash line in FIG. 3 is formed in a U-shaped cross section that opens downward so as to fit on the outer surface of the body 6. A through-hole 7 extending in the vertical direction is formed on the inner surface of the body 6 at a position where the electronic component 10a is provided. The energization line 9 is positioned so as to sandwich the through hole 7.

  As shown in FIG. 3, both energization lines 9 sandwiching the through hole 7 include a relaxation portion 11 that is bent obliquely upward with the through hole 7 side as a base end, and a distal end portion (upper portion) of the relaxation portion 11. Are formed so as to be bent so as to extend toward the through hole 7 in the horizontal direction. An electronic component 10 a is fixed to the upper surfaces of both installation portions 12. The same applies to the electronic component 10c. That is, the through-hole 7 is formed at a position corresponding to the electronic component 10 c of the body 6 and is fixed to the lead frame 8 by the relaxing portion 11 and the installation portion 12. In addition, a plurality of pins 19 having the same shape as the relaxing portion 11 and the installation portion 12 protrude from both side surfaces in the longitudinal direction of the electronic component 10b. The electronic component 10 b is fixed to the lead frame 8 via pins 19.

Next, a method for manufacturing the current sensor 1 will be described.
First, the cover 5 is formed by injection molding. Further, the body 6 is injection-molded in a state where a lead frame 8 that has been previously formed into a thin plate shape is inserted. Thereby, as shown in FIG. 4, the lead frame 8 is fixed to the inner surface of the body 6. At this time, the lead frame 8 forms the same surface as the inner surface of the body 6, and the ends of both energization lines 9 face each other in the vicinity of the center of the through hole 7.

  Next, both end portions of the energization line 9 facing each other in the through hole 7 are formed as follows. First, as shown in FIG. 5A, both end portions of the energization line 9 are rolled by press working or the like so as to be thinner than other portions. Thereby, the energization line 9 becomes easier to deform. And the both ends of the electricity supply line 9 are bend | folded as shown in FIG.5 (b) by pressing the end part of the thinned electricity supply line 9 through the through-hole 7. FIG. Thereby, as shown in FIG. 6, the relaxation part 11 and the installation part 12 of the lead frame 8 are formed. And as FIG. 3 shows, the electronic component 10a is fixed to the upper surface of both the installation parts 12 by laser welding. Similarly, the electronic part 10 c is also fixed to the installation part 12 by forming the relaxation part 11 and the installation part 12 in the energization line 9. Moreover, about the electronic component 10b, each pin 19 is adhere | attached on the electricity supply line 9 by welding. As a result, the electronic component 10b is fixed to the lead frame 8. Then, the cover 5 is fitted and fixed to the body 6 to complete the current sensor 1. Thus, since the lead frame 8 is bent to form the relaxing portion 11 and the installation portion 12, it is possible to reduce the number of parts compared to the case where they are formed by separate members. At the same time, the number of assembly steps can be reduced.

Next, the influence of the thermal stress generated in the current sensor 1 as the outside air temperature changes will be described.
The thermal stress is a stress generated inside the rigid body as the temperature of the rigid body changes. In the case of a material that can be deformed instead of a rigid body, a phenomenon of thermal expansion in which the length of the object is extended by a thermal stress generated with a temperature rise is observed. The amount of elongation (thermal strain) due to thermal expansion per unit length is determined by the coefficient of thermal expansion taking different values for each material. Here, the thermal expansion coefficient of the resin material is larger than that of metal or the like. For this reason, the body 6 is more likely to thermally expand due to a temperature rise than the lead frame 8 or the like.

  The thermal expansion of the body 6 is applied as an external force to the lead frame 8 fixed to the body 6, as shown in FIG. However, the relaxation portion 11 in the energization line 9 is provided so as to be deformable. That is, the relaxing part 11 is not restrained by the body 6. Therefore, as shown by a one-dot chain line in the left circle of FIG. 3 with respect to the thermal expansion of the body 6, the two relaxation portions 11 are bent and deformed in a convex shape when viewed from the outside, thereby pulling the electronic component 10a in the left-right direction. Application of force is suppressed. Similarly, even in the case of thermal contraction that occurs when the temperature is lowered, as shown by the alternate long and short dash line in the circle on the right side of FIG. 3, both relaxation portions 11 are bent and deformed in a concave shape when viewed from the outside. It is suppressed that the compression force in the left-right direction is applied to the component 10a. Thereby, generation | occurrence | production of the malfunction of the electronic component 10a accompanying the external force added by thermal expansion and thermal contraction is suppressed, and the reliability of operation | movement of the current sensor 1 can be improved by extension. Similarly, for the electronic component 10c, the relaxation portion 11 is elastically deformed, so that external force applied to the electronic component 10c due to thermal expansion or the like can be suppressed. Moreover, also about the electronic component 10b, since the pin 19 has the same shape as the relaxation part 11 and the installation part 12, the influence of the external force accompanying thermal expansion can be suppressed.

  Here, in the body 6, strictly speaking, although thermal expansion and thermal compression also occur in the vertical direction, the thickness of the body 6 in the vertical direction is sufficiently smaller than the length in the horizontal direction of the body 6, The influence on the electronic component 10a due to thermal expansion or the like can be ignored. Even if the body 6 is thermally expanded and compressed in the vertical direction, the electronic component 10a is slightly displaced in the vertical direction, and no large external force is generated in the electronic component 10a.

As described above, according to the embodiment described above, the following effects can be obtained.
(1) The body 6, which is a resin, thermally expands due to a change in the outside air temperature (more precisely, a temperature increase). Here, since the thermal expansion coefficient of the resin material is higher than that of metal or the like, the thermal strain due to the thermal expansion of the body 6 is large. External force is applied to the lead frame 8 fixed to the body 6 due to thermal expansion of the body 6. Due to the elastic deformation of the relaxing portion 11 formed on the electronic component 10a side of the lead frame 8 against this external force, the transmission of the external force to the electronic component 10a is suppressed. Thereby, generation | occurrence | production of the malfunction of the electronic component 10a is suppressed, and the reliability of operation | movement of the electronic component 10a is improved as a result. Moreover, according to the said structure, since a printed circuit board can be abbreviate | omitted, size reduction of the current sensor 1 is realizable simultaneously.

  Further, when the electronic component 10a is mounted by laser welding or the like, the relaxation portion 11 is deformed, so that an excessive external force is not applied to the electronic component 10a. Therefore, the electronic component 10a can be mounted without applying an extra external force.

  (2) The relaxation portion 11 is formed by bending a part of the lead frame 8. Therefore, it is not necessary to newly form the relaxing portion 11 as a separate member, and the reliability of the operation of the electronic component 10a can be increased without increasing the number of components constituting the current sensor 1.

(3) By installing the electronic component 10 a on the pair of installation portions 12, the electronic component 10 a can be more stably held from the lead frame 8 via the relaxation portion 11.
(4) The amount of elongation due to thermal expansion or the like is proportional to the length of the object. Therefore, since the through-hole 7 is formed in the body 6, the length of the body 6 in the left-right direction can be shortened, and as a result, thermal expansion and thermal compression can be suppressed. Thereby, the external force applied to the electronic component 10a can be further suppressed.

In addition, the said embodiment can be implemented with the following forms which changed this suitably.
In the above embodiment, the electronic component 10a is fixed to the upper surfaces of the both installation portions 12 by laser welding. However, as long as it can fix to both installation parts 12, you may fix with not only laser welding but soldering, an adhesive material, etc.

  In the above embodiment, the lead frame 8 is insert-molded on the body 6. However, the lead frame 8 may be fitted and fixed to the body 6 later. In this case, a groove in which the lead frame 8 is fitted is formed in the body 6. Further, the lead frame 8 may be bonded to the inner surface of the body 6 without forming a groove.

  In the above-described embodiment, the current sensor 1 is embodied as a package with an electronic component. However, the package is not limited to the current sensor as long as it is a package with an electronic component. In addition, the electronic components to be mounted are not limited to the Hall ICs and the amplifier circuits described in the above embodiment.

  In the above-described embodiment, both ends of the electronic component 10a are fixed in a state where both the installation portions 12 support the electronic component 10a. However, it may be supported by the single installation part 12, for example. In this case, the installation part 12 is formed so as to support a wide area of the lower surface of the electronic component 10a.

  In the above embodiment, as shown in FIG. 5A, after the opposing side end portion of the energization line 9 is formed thin, the relaxing portion 11 and the installation portion 12 are formed. However, the relaxation portion 11 and the installation portion 12 may be formed without extending the opposite end portion of the energization line 9 thinly. In this case, the lead frame 8 (energization line 9) is formed in a thin plate shape that can be elastically deformed in advance.

  In the above embodiment, the relaxing portion 11 and the installation portion 12 are formed by bending the energization line 9 of the lead frame 8. However, you may form the electricity supply line 9, the relaxation part 11, and the installation part 12 with another member. Specifically, as shown in FIG. 7, a connecting member 20 having a relaxation portion 11 and an installation portion 12 is provided separately from the lead frame 8. The connecting member 20 is formed by bending a conductive material (metal) with a press or the like. In addition to the relaxing part 11 and the installation part 12, the connecting member 20 is connected to the end of the relaxation part 11 on the opposite side of the installation part 12, and has an attachment part 21 that protrudes on the opposite side of the installation part 12. A mounting hole 22 extending in the vertical direction is formed in the mounting portion 21. On the other hand, a cylindrical positioning pin 25 that fits into the mounting hole 22 is formed on the upper surface of the opposite side end portions of the both energization lines 9. An electronic component 10a is fixed to the upper surface of the installation portion 12 of both connecting members 20 by laser welding or the like. Then, the mounting holes 22 of the mounting portions 21 of both the connecting members 20 integrated with the electronic component 10 a are fitted into the positioning pins 25 of the energization line 9. The connecting member 20 is fixed to the energization line 9 by laser welding or the like.

  When the fitting of the mounting hole 22 and the positioning pin 25 is a tight fit, the positioning pin 25 is press-fitted into the mounting hole 22 without being connected by laser welding or the like, and the connecting member 20 is inserted into the lead frame 8. Fixed. Thus, by connecting the lead frame 8 and the electronic component 10a with the connecting member 20, it is not necessary to form the through-hole 7 used at the time of pressing in the above embodiment. Further, since the connecting member 20 can be bent in advance, the electronic component 10a can be easily mounted by simply fixing the two connecting members 20 to which the electronic component 10a is attached to the energization line 9.

  In the above embodiment, the electronic component 10a is supported by the pair of installation portions 12. However, for example, as shown in FIG. 9, a relaxation member 50 made of, for example, conductive rubber may be fixed between the energization lines 9, and the electronic component 10 a may be fixed to the upper surface of the relaxation member 50. In this case, the upper surface of the relaxing member 50 corresponds to the installation portion 12. In this configuration, when an external force is applied to the energization line 9 due to thermal expansion of the body 6, the lower portion of the relaxation member 50 is deformed, and the bottom of the relaxation member 50 has a bottom as shown by a one-dot chain line in FIG. Long trapezoidal shape. As described above, the elastic member 50 is elastically deformed into a trapezoidal shape, thereby suppressing an external force from being applied to the electronic component 10a. Further, in this configuration, since the formation of the through hole 7 and the bending process of the lead frame 8 are not necessary, the work process can be reduced.

Next, the technical idea that can be grasped from the embodiment will be described together with the effects.
(A) The package with electronic components according to claim 2, wherein the relaxation portion of the lead frame is formed thinner than other portions of the lead frame.

  According to this configuration, the portion serving as the relaxation portion of the lead frame is formed thinner than other portions of the lead frame, and thus the relaxation portion is more easily elastically deformed. Therefore, the external force applied to the electronic component accompanying the thermal expansion of the body can be further suppressed.

(B) The package with an electronic component according to any one of claims 1 to 3 and (A), wherein the package with an electronic component is a current sensor.
In this configuration, the package with electronic components is a current sensor including a magnetic sensor such as a Hall IC, electronic components such as an amplifier circuit and a noise filter.

  DESCRIPTION OF SYMBOLS 1 ... Current sensor, 5 ... Cover, 6 ... Body, 7 ... Through-hole, 8 ... Lead frame, 9 ... Current supply line, 10a-10c ... Electronic component, 11 ... Relaxation part, 12 ... Installation part, 19 ... Pin, 20 ... connecting member, 50 ... relaxation member.

Claims (3)

In a package with an electronic component that is packaged by attaching a cover to a body made of a resin in which a lead frame for energizing the electronic component is fixed inside,
A package with an electronic component is provided between the lead frame and the electronic component, wherein a relaxation portion for separating the electronic component from the body is provided, and the relaxation portion is elastically deformed by a conductive material. In the package with an electronic component according to claim 1,
The relaxation part is a package with an electronic component formed by bending a part of the lead frame to the side opposite to the inner bottom surface of the body. In the package with an electronic component according to claim 1 or 2,
A package with an electronic component, wherein an installation portion on which the electronic component is installed is formed at an end portion of the relaxation portion opposite to the body so as to be parallel to an inner bottom surface of the body.

Images