JPH069169U - Capacitor mounting structure - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To alleviate the stress due to the difference in thermal expansion between the ceramic capacitor and the aluminum substrate or printed wiring board on which it is mounted. [Structure] One end of a polyamide-based flexible substrate 2 is soldered to an aluminum substrate or printed wiring board 1, one end of a ceramic capacitor 3 is directly soldered to the aluminum substrate or printed wiring substrate 1, and the other end is the flexible substrate. 2 is soldered to the other end. The flexible substrate 2 and the aluminum substrate or the required portions of the copper foil pattern portion 7 and the copper foil pattern portion 8 of the printed wiring board 1 are solder-printed using a metal mask, and the ceramic capacitor 3 is mounted at a predetermined position. After mounting other surface mount components, the soldering process is performed by reflow to obtain the solder portion 4, the solder portion 5, and the solder portion 6.
To form.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to surface mounting technology, and to a mounting structure of a capacitor.

[0002]

[Prior art]

 When mounting a ceramic capacitor on a printed wiring board using a hybrid IC or surface mounting technology, a cross-sectional view of the main part of the conventional capacitor mounting structure shown in FIG. 2 is used. Reflow soldering processing is performed after soldering the required parts of the copper foil pattern 18 of the printed wiring board 11 using a metal mask, mounting the ceramic capacitor 3 and mounting other surface mount components. Thus, the solder portion 14 and the solder portion 15 are formed. In this case, if the size of the capacitor is relatively small, such as length = 2 mm, width = 1.25 mm, thickness = 1 mm, there is no particular problem, but length = 5.7 mm, width = 2.7 mm, thickness = 1. In the case of a large size of about 8 mm, when mounted on an aluminum board or a printed wiring board, the coefficient of thermal expansion of these boards and the ceramic capacitors are significantly different, so that a large thermal stress may cause the ceramic capacitors to crack. Occurs.

[0003]

[Problems to be solved by the device]

 The present invention has been made in view of the above point, and for example, a large-sized capacitor having a length of 5.7 mm, a width of 2.7 mm, and a thickness of 1.8 mm is mounted on an aluminum substrate or a printed wiring board. Even in such a case, it provides a capacitor mounting structure in which the capacitor does not crack due to a large difference in thermal expansion coefficient.

[0004]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention is to mount a ceramic capacitor on an aluminum substrate or a printed wiring board by soldering, and the other end of the ceramic capacitor is connected to the aluminum substrate or the printed circuit board via a flexible substrate. To provide a capacitor mounting structure characterized by being connected to a wiring board.

[0005]

[Action]

 With the above configuration, in the capacitor mounting structure according to the present invention, one end of the ceramic capacitor is directly soldered to the aluminum substrate or the printed wiring board, while the other end is connected to the aluminum substrate via the flexible substrate. Since it is connected to the board or printed wiring board, the difference in thermal expansion between the ceramic capacitor and the aluminum board or printed wiring board is absorbed by the flexible and flexible flexible board, and the ceramic capacitor is prevented from cracking due to thermal stress. You can

[0006]

【Example】

 Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view of an essential part of an embodiment of a capacitor mounting structure according to the present invention. In the figure, 1 is an aluminum substrate or a printed wiring board, one end of a polyamide flexible substrate 2 is soldered to the aluminum substrate or the printed wiring board 1, 3 is a ceramic capacitor, and one end is the aluminum substrate directly. Alternatively, it is soldered to the printed wiring board 1 and the other end is soldered to the other end of the flexible substrate 2. In order to mount the ceramic capacitor 3 on the aluminum substrate or the printed wiring board 1, first, one end of the flexible substrate 2 is temporarily attached to a predetermined portion of the aluminum substrate or the printed wiring board 1 with an adhesive, and then the flexible substrate 2 and the aluminum are printed. The board or the required parts of the copper foil pattern portion 7 and the copper foil pattern portion 8 of the printed wiring board 1 are solder-printed using a metal mask, and the ceramic capacitor 3 has a predetermined end on the aluminum substrate or the printed board 1. The other end on the flexible substrate 2 at a predetermined position on the other end side (opposite side of the side where the adhesive is temporarily attached), and after mounting other surface mount components. Then, soldering processing is performed by reflow to form the solder portion 4, the solder portion 5, and the solder portion 6. Since one end of the ceramic capacitor 3 is mounted on the aluminum substrate or the printed wiring board 1 via the flexible substrate 2, the aluminum substrate or the printed wiring board 1 has a coefficient of thermal expansion of 2.5 which is equal to that of the ceramic capacitor 3. It has a coefficient of thermal expansion of up to 3.5 times, but this difference in coefficient of thermal expansion is absorbed by the flexible polyimide-based substrate.

[0007]

[Effect of device]

 As described above, in the capacitor mounting structure according to the present invention, one end of the ceramic capacitor is directly soldered to the aluminum substrate or the printed wiring board by soldering, while the other end is connected to the aluminum substrate via the flexible substrate. Since it is connected to the board or the printed wiring board, the difference in the amount of thermal expansion between the ceramic capacitor and the aluminum board or the printed wiring board is absorbed by the flexible and flexible flexible board, which makes it resistant to thermal stress. It also prevents the ceramic capacitors from cracking and can withstand a wide range of operating conditions. By using the flexible substrate, the conventional pattern of the aluminum substrate or the printed wiring board can be easily changed to the current pattern without increasing the conductor resistance.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of an embodiment of a capacitor mounting structure according to the present invention.

FIG. 2 is a cross-sectional view of a main part of an example of a conventional capacitor mounting structure.

[Explanation of symbols]

 1 Aluminum board or printed wiring board 2 Flexible board 3 Ceramic capacitor 4 Solder part 5 Solder part 6 Solder part 7 Copper foil pattern 8 Copper foil pattern

Claims (1)

[Scope of utility model registration request] 1. A ceramic capacitor mounted on an aluminum substrate or a printed wiring board by soldering, wherein the other end of the ceramic capacitor is connected to the aluminum substrate or the printed wiring board via a flexible substrate. Characteristic capacitor mounting structure.