JP2000208883A - Electronic circuit unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce warping at the periphery of an insulating substrate by mounting an electric part on a circuit pattern provided on one surface of the insulating substrate while a grid-like ground pattern comprising a pattern removing part is formed on the entire of the other surface. SOLUTION: An electronic circuit unit 1 comprises an insulating substrate 2 where insulators are laminated in multiple layers, and electric parts 3 such as resistors, capacitors, and IC parts, etc., which are, connected to a circuit pattern provided on an upper surface 2a of the insulating substrate 2, mounted on the upper surface 2. Further, a resist 6 is provided which is formed on the upper surface of a ground pattern 5 formed in grid comprising many pattern removing parts 5a over almost entire of a lower surface 2c except for a side electrode 4 drawn out to the lower surface 2c through a side edge part 2b of the insulating substrate 2 while connected to the circuit pattern. The pattern removing part 5a is rectangular while the ground pattern 5 is grid-like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic circuit unit such as a transmission / reception unit used for a portable telephone.

[0002]

2. Description of the Related Art A conventional electronic circuit unit will be described with reference to FIGS. 5 to 7. FIG. 5 is a side view showing a state in which the conventional electronic circuit unit is mounted on a mother board, and FIG. FIG. 7 is an explanatory view showing a warped state of a conventional electronic circuit unit with the resist removed.

[0003] The conventional electronic circuit unit 21 comprises:
As shown in FIGS. 5 to 7, an insulating substrate 22 formed by laminating insulators in multiple layers and a circuit pattern (not shown) provided on the upper surface 22 a of the insulating substrate 22 are connected to the upper surface 22 a. Except for the mounted electrical components 23 such as resistors, capacitors, and IC components, the side electrodes 24 drawn out to the lower surface 22c through the side edges 22b of the insulating substrate 22 while being connected to the circuit pattern, and the side electrodes 24 are excluded. Lower surface 2
On the entire surface of 2c, a ground pattern 25 in which copper foil is formed in a solid shape and a resist 26 formed on the upper surface of the ground pattern 25 are formed.

Then, such an electronic circuit unit 21
Is placed on the motherboard 27 as shown in FIG.
A side electrode 24 is attached to a conductive pattern (not shown) provided on the motherboard 27 by soldering 28, and the electronic circuit unit 21 is surface-mounted on the motherboard 27. In general, various tests are performed on such an electronic circuit unit 21. As a result of performing a temperature cycle test in a state where the electronic circuit unit 21 is surface-mounted on the motherboard 27, warpage of the outer peripheral portion of the insulating substrate 22 is found. As a result, the connection between the conductive pattern of the mother board 27 and the side electrode 24 by the solder 28 was broken, and many connection failures occurred.

Therefore, as a result of analyzing the connection breakdown of the solder 28, as shown in FIG. 7, when the insulating substrate 22 having a thickness of 1 mm is used, the outer peripheral portion is determined with reference to the center of the insulating substrate 22. Warpage occurs, and the warp T is 0.2 mm
It was the size of.

[0006]

The conventional electronic circuit unit has a configuration in which the ground pattern 25 is provided in a substantially solid state on almost the entire lower surface 22c of the insulating substrate 22, so that the periphery of the side edge portion 22b is provided. When the electronic circuit unit 21 is used in an external environment in a state in which the electronic circuit unit 21 is soldered to the mother board 27 in a state where the electronic circuit unit 21 is soldered to the mother board 27, there is a problem that a large number of connection failures occur.

[0007]

As a first means for solving the above problems, a circuit pattern is provided on one surface of an insulating substrate, and electric components are connected to the circuit pattern and mounted. In addition, on the other surface of the insulating substrate, a mesh-like ground pattern having a pattern removing portion is formed on almost the entire surface. As a second solution, the ground pattern has a configuration in which an area of the ground pattern at an outer peripheral portion of the insulating substrate is smaller than an area of the ground pattern at a central portion of the insulating substrate. Further, as a third solution, the width of the ground pattern at the outer peripheral portion of the insulating substrate is formed to be smaller than the width of the ground pattern at the center of the insulating substrate.

[0008]

FIG. 1 shows an electronic circuit unit according to the present invention.
FIG. 1 is a side view showing a state where the electronic circuit unit of the present invention is mounted on a mother board,
FIG. 2 is a bottom view of the electronic circuit unit according to the first embodiment of the present invention with the resist removed, and FIG. 3 is a view of the second embodiment of the electronic circuit unit of the present invention with the resist removed. FIG. 4 is an explanatory view showing a warped state of the electronic circuit unit of the present invention.

A first embodiment of an electronic circuit unit 1 according to the present invention, as shown in FIGS. 1 and 2, comprises an insulating substrate 2 in which insulators are laminated in multiple layers, and an upper surface of the insulating substrate 2. The electrical component 3 such as a resistor, a capacitor, and an IC component mounted on the upper surface 2a is connected to a circuit pattern (not shown) provided on the upper surface 2a.
A side electrode 4 drawn out to the lower surface 2c through the side edge 2b of the insulating substrate 2 and a ground pattern 5 formed in a mesh shape having a large number of pattern removing portions 5a on almost the entire lower surface 2c except for the side electrode 4. And a resist 6 formed on the upper surface of the ground pattern 5.

In the first embodiment, as shown in FIG. 2, the pattern removing section 5a is formed in a rectangular shape, and the ground pattern 5 has a mesh shape. The width A1 of the portion 5a is 0.4 mm, the width A2 between the pattern removing portions 5a is also 0.4 mm, and the mesh-like ground pattern 5 having the aligned pattern removing portions 5a.
Is formed.

FIG. 3 shows a second embodiment of the present invention. In this embodiment, the ground pattern 5 is
The area of the ground pattern 5 in the outer peripheral portion of the
Is smaller than the area of the ground pattern 5 in the central portion of FIG. As an example of the specific configuration, as shown in FIG. 3, the width A3 of the pattern removing portion 5a at the outer peripheral portion of the insulating substrate 2 is 0.6 mm, and the width A4 between the pattern removing portions 5a is 0.2 mm. And the insulating substrate 2
The width A5 of the pattern removing portion 5a at the center of
mm, and the width A6 between the pattern removing portions 5a is also 0.4 m.
m, the ground pattern 5 on the outer peripheral portion of the insulating substrate 2
Is smaller than the width A6 of the ground pattern 5 at the center of the insulating substrate 2 so that the area of the ground pattern 5 at the outer periphery is smaller than the area of the ground pattern 5 at the center. .

Then, such an electronic circuit unit 1
As shown in FIG. 1, the electronic circuit unit 1 is mounted on a mother board 7, and a side electrode 4 is attached to a conductive pattern (not shown) provided on the mother board 7 by soldering 8. It is designed to be surface-mounted on the substrate 7.
Generally, various tests are performed on such an electronic circuit unit 1. As a result of performing a temperature cycle test in a state where the electronic circuit unit 1 is surface-mounted on the mother board 7, the warpage of the insulating board 2 is small, As a result, there was little breakage due to the solder 8 between the conductive pattern of the substrate 7 and the side electrode 4 and the occurrence of poor connection was reduced.

As a result of analyzing the warpage of the insulating substrate 2 in the first and second embodiments, as shown in FIG.
When the insulating substrate 22 having a thickness of 1 mm is used, in the first embodiment, a warp occurs at an outer peripheral portion with respect to a central portion of the insulating substrate 2, and the warp t1 is 0.1 mm. In the second embodiment, the warp t1 is 0.03
mm, which could be made smaller than before.

[0014]

According to the electronic circuit unit of the present invention, the pattern removing portion 5 is provided on almost the entire lower surface 2c of the insulating substrate 2.
Since the mesh-shaped ground pattern 5 having a is provided, the warpage in the outer peripheral portion of the insulating substrate 2 can be reduced as compared with the related art, and the connection failure due to the solder 8 with the mother substrate 7 can be reduced. Units can be provided. Further, the ground pattern 5 is formed such that the area of the ground pattern 5 at the outer peripheral portion of the insulating substrate 5 is smaller than the area of the ground pattern 5 at the central portion of the insulating substrate 2, thereby further warping the outer peripheral portion of the insulating substrate 2. Can be reduced, and an electronic circuit unit with extremely few connection failures can be provided. Also,
By forming the width of the ground pattern 5 at the outer peripheral portion of the insulating substrate 2 to be smaller than the width of the ground pattern 5 at the central portion of the insulating substrate 2, warpage at the outer peripheral portion of the insulating substrate 2 can be further reduced. Thus, an electronic circuit unit with extremely few connection failures can be provided.

[Brief description of the drawings]

FIG. 1 is a side view showing a state where an electronic circuit unit of the present invention is mounted on a mother board.

FIG. 2 is a bottom view of the electronic circuit unit according to the first embodiment of the present invention, with a resist removed.

FIG. 3 is a bottom view of a second embodiment of the electronic circuit unit according to the present invention, with a resist removed.

FIG. 4 is an explanatory diagram showing a warped state of the electronic circuit unit of the present invention.

FIG. 5 is a side view showing a state in which a conventional electronic circuit unit is mounted on a mother board.

FIG. 6 is a bottom view of a conventional electronic circuit unit with a resist removed.

FIG. 7 is an explanatory view showing a warped state of a conventional electronic circuit unit.

[Explanation of symbols]

 Reference Signs List 1 electronic circuit unit 2 insulating substrate 2a upper surface 2b side edge 2c lower surface 3 electric component 4 side electrode 5 ground pattern 5a pattern removing portion 6 resist 7 mother substrate 8 solder A1 width A2 width A3 width A4 width A5 width A6 width

Claims (3)

[Claims] 1. A circuit pattern is provided on one surface of an insulating substrate, and an electric component is connected to and mounted on the circuit pattern. An electronic circuit unit, wherein a mesh-like ground pattern having a pattern removing portion is formed. 2. The ground pattern according to claim 1, wherein an area of the ground pattern in an outer peripheral portion of the insulating substrate is smaller than an area of the ground pattern in a central portion of the insulating substrate. Electronic circuit unit. 3. The electronic circuit according to claim 2, wherein a width of the ground pattern at an outer peripheral portion of the insulating substrate is smaller than a width of the ground pattern at a central portion of the insulating substrate. unit.