JP3847136B2 - Electronic components - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic component, and more particularly to an electronic component that is mounted on a substrate by a dipping method immersed in a molten solder bath.
[0002]
[Prior art]
Conventionally, as shown in FIG. 5, an element in which a piezoelectric element 1 and a capacitor substrate 3 are stacked in a thickness direction at a predetermined interval is disposed between U-shaped holding portions 9 at the tip portions of a pair of lead terminals 5 and 7. Further, after the lead terminal 11 on the earth side is brought into contact with the electrode 13 of the capacitor substrate 3, the piezoelectric element 1 and the electrode of the capacitor substrate 3 are joined to the respective lead terminals 5, 7, 11 by soldering, and the piezoelectric An electronic component is formed by covering the center portion of the element 1 with a coating resin so as to form a cavity capable of vibration.
[0003]
In an electronic component having such a lead terminal, conventionally, after the end portions of the lead terminals 5, 7, and 11 are inserted into a board insertion hole and temporarily fixed, the lead terminal is inserted into the board insertion hole. The electronic component and the substrate are mechanically fixed and electrically connected by a solder dip in which end portions of 5, 7, and 11 are immersed in a solder bath.
[0004]
However, when the ends of the lead terminals 5, 7, and 11 are immersed in the solder bath, the temperature of the three lead terminals 5, 7, and 11 increases with time mainly due to heat conduction. When the temperature of the solder joint portion of the lead terminal 11 reaches the melting point of the solder, there is a problem that the solder melts and the lead terminal 11 is peeled off from the electrode 13 of the capacitor substrate 3, resulting in poor connection.
[0005]
That is, the electrode 13 forming surface of the capacitor substrate 3 and the extending direction of the lead terminal 11 are substantially parallel, and one end of the lead terminal 11 is soldered in a state of being in contact with the electrode 13 of the capacitor substrate 3. When the solder is melted by heating the lead terminal 11, there is a problem that one end of the lead terminal 11 is easily peeled off from the electrode 13 of the capacitor substrate 3.
[0006]
In other words, the other end portion of the lead terminal 11 is inserted into the insertion hole of the substrate and joined to the substrate by soldering by a dipping method. However, as the solder is cooled and solidified, one end portion of the lead terminal 11 becomes the electrode 13 of the capacitor substrate 3. There is a problem that a force to move away from the electrode is easily applied, and one end portion of the lead terminal 11 is peeled off from the electrode 13 of the capacitor substrate 3 due to the melting of the solder joint with the electrode 13 due to the heating of the lead terminal 11. .
[0007]
Therefore, conventionally, in order to shorten the solder dip time or lengthen the time until the solder joint between the lead terminal 11 and the electrode 13 reaches a certain temperature, the coating is performed to increase the heat capacity of the coating resin forming the cavity. The bulk of the resin was controlled to be above a certain level.
[0008]
[Problems to be solved by the invention]
However, according to the method for increasing the volume of the coating resin described above, the rate of temperature rise at the solder joint between the one end portion of the lead terminal 11 and the electrode 13 of the capacitor substrate 3 can be moderated. Therefore, it is necessary to carry out manufacturing management with a larger volume in view of the safety side so that the rate of temperature rise is slower, which is disadvantageous for downsizing of the product.
Further, the temperature at which the lead terminals 5, 7, and 11 finally reach after solder dipping hardly depends on the volume of the coating resin. Therefore, in the method of increasing the volume, it is necessary to strictly control the solder dipping time. In addition, there is a problem that the manufacturing process is complicated, for example, strict temperature control is required.
[0009]
Furthermore, if the solder dipping time is controlled to be extremely short so that the lead terminal temperature does not reach a temperature higher than the specified value without increasing the bulk of the coating resin, the connection to the connection portion between the board and the lead terminal can be reduced. Since solder wraparound is reduced, mechanical and electrical coupling between the electronic component and the substrate is insufficient, and it is difficult to obtain stable characteristics.
[0010]
Particularly in recent years, miniaturization and low profile have been demanded, the length of the lead terminal has been shortened, the distance from the junction with the substrate to the electrode of the capacitor substrate has also been shortened, and the solder There was a problem that the joint was easily heated.
[0011]
An object of this invention is to provide the electronic component which can improve the soldering joint reliability of an electronic component main body and a lead terminal.
[0012]
[Means for Solving the Problems]
The electronic component according to the present invention includes an electronic component body having a plurality of electrodes, one end holding and fixing the electronic component body, and the other end connected to the substrate by soldering, and one end An electronic component comprising: a contact bonding lead terminal bonded to the substrate by solder while being in contact with an electrode of the electronic component main body, and having the other end bonded to the substrate by solder. A heat conduction suppressing portion for suppressing heat conduction to the electronic component main body is formed in the lead terminal, and the electronic component main body is a portion on the electronic component main body side of the holding and fixing lead terminal and the lead terminal for contact joining It is characterized by being covered with a coating resin together with a part on the electronic component main body side including the heat conduction suppressing part .
[0013]
In such an electronic component, when the other end of the holding and fixing lead terminal and the abutting and joining lead terminal is inserted into the insertion hole of the substrate and this part is immersed in a solder bath, the lead terminal is mainly formed by heat conduction. Although the temperature rises with time, a heat conduction suppressing portion that suppresses heat conduction to the electronic component body is formed on the lead terminal for contact bonding that is joined by solder while being in contact with the electrode of the electronic component body. Therefore, heat conduction from the solder bath to the electronic component main body is suppressed, and it is possible to suppress the release of solder bonding between the electrode of the electronic component main body and one end portion of the lead terminal for contact bonding. Reliability can be improved.
[0014]
Further, in the present invention, it is desirable that the heat conduction suppressing portion is formed by bending or bending at least a part of the contact bonding lead terminal. Thereby, the heat conduction path from the substrate side to the electrode of the electronic component main body becomes long, the thermal resistance increases, the temperature drop can be increased, the heat conduction to the electronic component main body can be suppressed, and the electrode of the electronic component main body, It is possible to improve the solder joint reliability with one end of the contact joining lead terminal.
[0015]
Furthermore, the present invention can be applied to the case where the extending direction of the abutting joining lead terminal and the forming surface of the electrode to which one end of the corresponding joining joining lead terminal is joined are substantially parallel. desirable.
[0016]
As described above, the extending direction of the contact bonding lead terminal is substantially parallel to the electrode forming surface of the electronic component body, and one end of the contact bonding lead terminal is in contact with the electrode formed on this surface. In the case where the solder is joined in such a state, the joint is easily released due to the high temperature of the joint. Even so, it is possible to effectively prevent the joint from being released.
[0017]
In particular, the electronic component main body includes a piezoelectric element in which vibration electrodes are formed on opposite surfaces of the piezoelectric ceramic, and a capacitor substrate in which electrodes are formed on both main surfaces of the dielectric ceramic. In the case where bonding is performed in a state where one end portion of the contact bonding lead terminal is in contact with the electrode of the substrate, the bonding portion is easily released due to the high temperature of the bonding portion, so that the present invention is significant.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a front view of the electronic component of the present invention, and FIG. 2 is an exploded perspective view. As shown in FIG. 1, the electronic component of the present invention is covered with a coating resin 31 so as to embed an electronic component main body composed of a piezoelectric element and a capacitor substrate, and has three lead terminals 33, 35, and 37 in the same direction. It is constituted by extending.
[0019]
These lead terminals 33 and 37 are mainly holding and fixing lead terminals 33 and 37 which serve to hold and fix both ends of the electronic component main body, and one end portion of the central lead terminal 35 is the electronic component main body. In this state, the lead terminal 35 is joined by solder in a state of being in contact with the electrode, and mainly serves as an electrical connection.
[0020]
That is, as shown in FIG. 2, the electronic component main body 39 has a piezoelectric element 45 formed by forming a pair of vibrating electrodes 43, 44 on opposite surfaces of the piezoelectric ceramic 41 and electrodes on both main surfaces of the dielectric ceramic 47. The vibrating electrodes 43 and 44 of the piezoelectric element 45 constituted by the capacitor substrate 53 formed with 49 and 51 are formed so as to extend to the end of the piezoelectric ceramic 41. The capacitor substrate 53 has individual electrodes 49a and 49b formed on one main surface of the rectangular dielectric ceramic 47 and common potential side electrodes 51a and 51b formed on the other main surface in order to form two capacitor components. Yes. Specifically, the common potential side electrodes 51 a and 51 b are formed so that the end portions of the dielectric ceramic 47 are exposed, and the individual electrodes 49 a and 49 b are formed so as to extend to the end portions of the dielectric ceramic 47. ing.
[0021]
At one end portions of the holding and fixing lead terminals 33 and 37, holding portions 55 and 57 for holding and fixing both end portions of the electronic component main body 39 are formed. As shown in FIG. 57, the electronic component main body 39 is held and fixed with solder, and the vibration electrode 43 of the piezoelectric element 45, the individual electrode 49a of the capacitor substrate 53, and the holding portion 55 of the holding and fixing lead terminal 33 are electrically connected. Then, the vibration electrode 44 of the piezoelectric element 45, the individual electrode 49b of the capacitor substrate 53, and the holding portion 57 of the holding and fixing lead terminal 37 are electrically connected.
[0022]
In addition, one end portion of the contact bonding lead terminal 35 is substantially T-shaped or Y-shaped so as to be electrically connected across the common potential side electrodes 51a and 51b, and a solder pool is formed. A connecting portion 59 having a curved structure is formed, and the connecting portion 59 is joined by solder while being in contact with the common potential side electrodes 51a and 51b. The surface of the capacitor substrate 53 on which the common potential side electrodes 51 a and 51 b are formed is substantially parallel to the extending direction of the contact bonding lead terminal 35.
[0023]
In the present invention, the heat conduction suppressing portion 63 that suppresses heat conduction to the electronic component main body 39 is formed in the contact bonding lead terminal 35. The heat conduction suppressing portion 63 is configured by bending a part of the contact bonding lead terminal 35, whereby the heat conduction path becomes longer, the thermal resistance increases, and the temperature drop can be increased. Heat conduction to the component main body 39 can be suppressed, and the reliability of solder bonding between the electrode 51 of the electronic component main body 39 and one end of the contact bonding lead terminal 35 can be improved.
[0024]
The bending angle of the contact bonding lead terminal 35 is preferably 15 to 90 degrees. For example, as shown in FIG. 4, even if a part of the contact bonding lead terminal 35 is bent to form the heat conduction suppressing portion 65, the same effect as described above can be obtained.
[0025]
Needless to say, the heat conduction suppressing portion 63 may be formed by bending a part of the contact bonding lead terminal 35.
[0026]
In addition, it is desirable that the heat conduction suppressing portion 63 of the contact bonding lead terminal 35 has a smaller cross-sectional area than other portions. Thereby, thermal resistance further increases, a temperature drop can be increased, and heat conduction to the electronic component main body 39 can be suppressed.
[0027]
Further, it is desirable that the length of the bent portion or the curved portion is in the range of 150 to 300% of the distance between the lead terminals 33, 35 and 37. Thereby, a necessary thermal resistance can be ensured without causing an extreme signal voltage drop.
[0028]
In the electronic component configured as described above, the other ends of the holding and fixing lead terminals 33 and 37 and the abutting and joining lead terminal 35 are inserted into the insertion hole of the substrate, and this portion is immersed in a solder bath. Mounted on the board.
[0029]
The temperature of the lead terminals 33, 35, and 37 increases with time due to heat conduction during immersion in the solder bath, but the contact bonding lead terminals 35 are joined by solder while being in contact with the electrodes 51 of the electronic component body 39. Since the heat conduction suppressing portion 63 that suppresses heat conduction to the electronic component main body 39 is formed, heat conduction to the electronic component main body 39 is suppressed, and the electrode 51 of the electronic component main body 39 is brought into contact contact with The solder joint property with the one end part of the lead terminal 35 can be improved, and the electrical connection reliability can be improved.
[0030]
The holding and fixing lead terminals 33 and 37 also rise in temperature in the same manner as the abutting and joining lead terminal 35, but holding portions 55 and 57 are formed at one end thereof, and the electronic component main body 39 is held and fixed. Therefore, the release of the electrical connection due to the melting of the solder hardly occurs. However, as shown in FIG. 2, the contact bonding is performed by solder bonding in a state of contacting the electrode 51 formed on the side surface of the electronic component main body 39. In the lead terminal 35, one end portion of the contact bonding lead terminal 35 is melted by heating the bonding portion, and the solder for bonding the other end portion of the contact bonding lead terminal 35 to the substrate is cooled and solidified. However, since a stress that tends to be separated from the electrode 51 formed on the side surface of the electronic component main body 39 is generated, it is significant to apply the present invention to an electronic component having such a contact bonding lead terminal 35.
[0031]
Further, since the heat conduction suppressing portion 63 of the contact bonding lead terminal 35 is embedded in the coating resin 31 described above, it is easy to handle electronic components, and contact with the insertion hole of the substrate is possible. The joining lead terminal 35 can be easily inserted.
[0032]
【The invention's effect】
As described above, in the electronic component of the present invention, when the other end part of the holding and fixing lead terminal and the abutting and joining lead terminal is inserted into the insertion hole of the substrate and this part is immersed in the solder bath, the heat component is mainly heated. Although the temperature of the lead terminal rises with time due to conduction, the lead terminal for contact joining that is joined by solder while in contact with the electrode of the electronic component main body has heat conduction that suppresses heat conduction to the electronic component main body. Since the suppression portion is formed, heat conduction to the electronic component body is suppressed, and the solder joint between the electrode of the electronic component body and one end portion of the contact bonding lead terminal is released at the time of mounting on the substrate. This can be suppressed, and electrical connection reliability and mechanical joint reliability can be improved.
[Brief description of the drawings]
1A and 1B show an electronic component of the present invention, in which FIG. 1A is a front view and FIG. 1B is a side view;
FIG. 2 is an exploded perspective view of an electronic component in which an exterior resin of the present invention is omitted.
FIG. 3 is a plan view of an electronic component in which an exterior resin of the present invention is omitted.
FIG. 4 is an exploded perspective view showing another electronic component of the present invention.
FIG. 5 is an exploded perspective view of an electronic component in which a conventional exterior resin is omitted.
[Explanation of symbols]
33, 37 ... holding and fixing lead terminals 35 ... contact joining lead terminals 39 ... electronic component main body 41 ... piezoelectric ceramics 43, 44 ... vibrating electrodes 45 ... piezoelectric elements 47 ..Dielectric porcelain 49a, 49b, 51a, 51b ... Electrode 53 of capacitor substrate ... Capacitor substrate 63 ... Heat conduction suppressing part

Claims (5)

An electronic component main body having a plurality of electrodes, one end holding and fixing the electronic component main body, the other end connected to the substrate by soldering, and one end connected to the electrode of the electronic component main body An electronic component comprising: a contact joining lead terminal joined by solder in a contact state and the other end joined to the substrate by solder, wherein the electronic component is connected to the contact joining lead terminal. A heat conduction suppressing portion that suppresses heat conduction to the main body is formed, and the electronic component main body includes a portion of the holding and fixing lead terminal on the electronic component main body side and a heat conduction suppressing portion of the contact bonding lead terminal. An electronic component that is coated with a coating resin together with a portion on the electronic component main body side . 2. The electronic component according to claim 1, wherein the heat conduction suppressing portion is formed by bending or bending at least a part of the contact terminal for contact. 3. The extending direction of the abutting joining lead terminal and the formation surface of the electrode to which one end of the corresponding joining joining lead terminal is joined are substantially parallel to each other. Electronic components. 4. The electronic component according to claim 1, wherein the heat conduction suppressing portion of the contact terminal for contact has a smaller cross-sectional area than other portions. The electronic component body includes a piezoelectric element formed with vibration electrodes on opposing surfaces of the piezoelectric ceramic, and a capacitor substrate formed with electrodes on both main surfaces of the dielectric ceramic. 5. The electronic component according to claim 1, wherein the electronic component is bonded to the electrode in a state in which one end portion of the contact bonding lead terminal is in contact with the electrode.

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