JP2015122415A - Printed circuit board and on-board equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce application and drying operations for a moisture-proof coating agent.SOLUTION: In a printed circuit board 10 held in the state of being inclined by an attachment angle θ with respect to a horizontal plane, a protrusion 12, which is formed by heaping up solder, is formed on an inclination-direction upside with respect to a surface mounted component 11 on a downward back surface of the printed circuit board 10 and on a line crossing the inclination direction. Thus, a direction of a liquid flowing in the inclination direction (an arrow C) in such a manner as to run on the back surface of the printed circuit board 10 is changed (an arrow D) or the liquid is dropped (an arrow E) to prevent the surface mounted component 11 from being covered with water.

Description

  The present invention relates to a printed circuit board having a waterproof structure for mounting components, and an in-vehicle device that accommodates the printed circuit board.

  In recent years, in-vehicle devices have been subjected to a moisture test as an enhancement of practical use resistance. This is a test in which it is assumed that the user has accidentally spilled a liquid such as a beverage drink, and the liquid is applied to the design panel surface of the in-vehicle device to check whether there is a failure. In order to avoid the occurrence of leakage and migration due to humidity or moisture, such as narrow pitch components and high impedance circuits mounted on a printed circuit board, a moisture-proof coating agent is generally applied (see, for example, Patent Document 1). .

JP 2002-246733 A

  When the moisture-proof coating agent is applied to the printed circuit board, not only the material cost and work time required for the application but also the time required for drying is required, so that the manufacturing efficiency of the mounting board is deteriorated. When the application location is on both the front and back sides of the printed circuit board, the efficiency is doubled.

  The present invention has been made to solve the above-described problems, and an object thereof is to reduce application of a moisture-proof coating agent and drying work.

  The printed circuit board according to the present invention is held in an inclined state with respect to a horizontal plane, and when the printed circuit board is installed, the printed circuit board faces downward and is inclined above the mounting component and in the inclined direction. Protrusions on which solder is formed are provided on the intersecting lines.

  The in-vehicle device according to the present invention accommodates the above-described printed circuit board and is installed to be inclined so that the printed circuit board is inclined with respect to a horizontal plane.

  According to the present invention, the mounting part is exposed to water by causing the convex portion where the solder is piled up to function as an embankment, changing the direction of the liquid flowing in the inclined direction along the back surface of the printed circuit board, or dropping the liquid. Do not. Therefore, it is sufficient to apply the moisture-proof coating agent only to the surface of the printed circuit board, and the application and drying operations can be reduced.

It is a figure explaining the example of the moisture test method of the vehicle equipment which concerns on Embodiment 1 of this invention. The structure of the printed circuit board concerning Embodiment 1 is shown, Fig.2 (a) is a X arrow directional view, FIG.2 (b) is a side view. 6 is a plan view showing another configuration example of the printed circuit board according to Embodiment 1. FIG. 6 is a plan view showing another configuration example of the printed circuit board according to Embodiment 1. FIG. 6 is a plan view showing another configuration example of the printed circuit board according to Embodiment 1. FIG. 6 is a plan view showing another configuration example of the printed circuit board according to Embodiment 1. FIG. It is a X arrow line view which shows the structure of the printed circuit board concerning Embodiment 2 of this invention. It is a figure explaining the difference of the effect of the several convex part (FIG. 8 (a)) of Embodiment 2, and the convex part (FIG.8 (b)) of Embodiment 1. FIG.

Embodiment 1 FIG.
FIG. 1 shows an example of a water test method for an in-vehicle device 1 according to Embodiment 1 of the present invention, and shows a state in which the in-vehicle device 1 is viewed from the side. 2A is an arrow view of the printed circuit board 10 accommodated in the in-vehicle device 1 as viewed from the X direction in FIG. 1, and FIG. 2B is a side view.
A vehicle-mounted device 1 such as a car navigation device or a car audio device is held in a state inclined by an attachment angle θ with respect to a horizontal plane. In the wet test, the liquid 4 placed in the cup 3 is poured from the upper part of the design panel 2 to be wet. At this time, the liquid enters the inside of the in-vehicle device 1 from an opening (not shown) formed in the design panel 2 (for example, a disc insertion opening). The infiltrated liquid falls onto the printed circuit board 10 arranged inside the in-vehicle device 1 (arrow A in FIG. 2B), and further flows on the surface of the printed circuit board 10 (arrow B in the figure). It flows from the edge along the back surface (arrow C in the figure). Usually, the in-vehicle device 1 is attached to the vehicle with the design panel 2 facing upward and has a certain attachment angle θ (for example, 30 degrees), so that the liquid-wetting path (arrows B and C) flowing through the printed circuit board 10 is used. Can be specified from the front on the design panel 2 side to the rear. In other words, the wet path (arrows B and C) and the inclination direction of the printed board 10 are substantially parallel, and the liquid flows from the upper side to the lower side in the inclination direction.

  In the first embodiment, the mounting component 11 (for example, a narrow pitch component, a high impedance circuit) mounted on the back surface of the printed circuit board 10 is not wetted by the mounting component 11 as shown in FIG. A mountain-shaped land with the upper side in the tilt direction at the top is formed in front, and solder is deposited on this land to provide the convex portion 12. As a result, the liquid that has traveled along the back surface of the printed circuit board 10 as indicated by the arrow C is separated from the left and right by the convex portion 12 and flows away (arrow D). Alternatively, as shown in FIG. 2B, the liquid that has traveled along the back surface of the printed board 10 as indicated by the arrow C falls at the convex portion 12 (arrow E). In this way, the mounting component 11 can be prevented from getting wet.

The convex portion 12 may be formed by providing a land on the back surface of the printed circuit board 10 and depositing solder on the land, or stripping the resist on the back surface of the printed circuit board 10 to expose the solid ground, and soldering the exposed portion. You may form by piling up.
The soldering method may be any method such as a dip method or a flow method.

Next, some modified examples of the convex portion 12 will be described.
3 to 6 are arrow views of the printed circuit board 10 as viewed from the X direction in FIG. In the modification of FIG. 3, a linear convex portion 12 a that intersects the water-receiving path substantially at a right angle is provided in front of the water-receiving path from the mounting component 11 on the back surface of the printed circuit board 10. In the modification of FIG. 4, the linear convex part 12b which cross | intersects diagonally with respect to a to-be-watered path | route is provided. In the modification of FIG. 5, the curved convex part 12c which cross | intersects a to-be-watered path | route is provided. In the modification of FIG. 6, a frame-shaped convex portion 12 d that intersects the water-protected path and surrounds the mounting component 11 is provided.
Similarly to the convex portion 12, the convex portions 12 a to 12 d change the direction of the liquid that travels on the back surface of the printed circuit board 10 or drops the liquid, so that the mounting component 11 can be prevented from getting wet.

In addition, since the height of the convex parts 12, 12a to 12d is limited due to the structure in which the solder is piled up, it is considered that the wet prevention effect is large on the back surface of the printed circuit board 10 through which a small amount of liquid is transmitted by the surface tension effect. Therefore, in FIGS. 2 to 6, protrusions 12, 12 a to 12 d are provided on the back surface of the printed circuit board 10 to prevent water exposure. On the other hand, the surface of the printed circuit board 10 is coated with a moisture-proof coating agent to prevent water exposure as in the past.
Thereby, application | coating of a moisture-proof coating agent and a drying operation can be reduced compared with the case where moisture-proof coating is carried out on both the front and back of the printed circuit board 10 conventionally.

  As described above, according to the first embodiment, when the printed circuit board 10 is installed with the mounting angle θ, the soldering is performed on the back surface facing downward from the mounting component 11 and on the line intersecting the tilt direction. Since the convex portions 12, 12a to 12d are provided, the direction of the liquid flowing in the inclined direction (that is, the arrow C in FIG. 2) along the back surface of the printed circuit board 10 is changed or the liquid is dropped. Thus, the mounting component 11 can be prevented from getting wet. Accordingly, it is sufficient to apply the moisture-proof coating agent only to the surface of the printed circuit board 10, and the application and drying operations can be reduced.

Embodiment 2. FIG.
7 is an arrow view of the printed circuit board 10 according to the second embodiment of the present invention as viewed from the X direction of FIG. FIG. 8 is an enlarged view of the convex portion when the printed circuit board 10 is viewed from the side surface direction. FIG. 8A shows the convex portions 12-1 to 12-3 of the second embodiment, and FIG. The convex part 12 of the said Embodiment 1 is shown. 7 and 8, the same or corresponding parts as those in FIGS. 1 to 6 are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 7, in the second embodiment, a plurality of convex portions 12-1 to 12-3 arranged in the inclination direction are formed in front of the wet route from the mounting component 11. By forming a plurality of convex portions 12-1 to 12-3 as shown in FIG. 8A, the surface area is increased as compared with the case where a single convex portion 12 is formed as shown in FIG. 8B. However, the surface tension of the liquid 4 on the convex portions 12-1 to 12-3 brings about an effect that the liquid 4 tries to stay there. Therefore, as compared with the case where the convex portion 12 is configured by one, the effect of preventing the infiltration of a larger amount of the liquid 4 can be obtained more reliably.

In FIG. 7 and FIG. 8A, three convex portions 12-1 to 12-3 are formed, but the number may be arbitrary.
Moreover, although the example which formed multiple mountain-shaped convex parts was shown, you may form several linear, curved, and frame-shaped convex parts as shown in FIGS.

  As described above, according to the second embodiment, since the plurality of convex portions 12-1 to 12-3 are formed along the inclination direction of the printed circuit board 10, a larger amount of the liquid 4 can be obtained more reliably. Can be prevented from entering.

The printed circuit board 10 according to the present invention is suitable for use in an electronic device, particularly the in-vehicle device 1, which is installed at an inclination, since the solder is piled up and embanked so as to intersect the wet route.
Since the in-vehicle device 1 is attached at an inclination, the printed board 10 accommodated in the in-vehicle apparatus 1 is also inclined in the same manner, but the in-vehicle apparatus 1 is attached horizontally and the printed board 10 is inclined therein. Even in the case of a construction that accommodates it, it has an effect of preventing water exposure.

  In addition to the above, within the scope of the present invention, the present invention can be freely combined with each embodiment, modified any component of each embodiment, or omitted any component in each embodiment. Is possible.

  DESCRIPTION OF SYMBOLS 1 In-vehicle apparatus, 2 design panel, 3 cups, 4 liquid, 10 printed circuit board, 11 mounting components, 12, 12a-12d, 12-1-12-3 convex part, (theta) mounting angle.

Claims (4)

A printed circuit board held in an inclined state with respect to a horizontal plane,
A printed circuit board comprising a convex portion on which solder is piled up on a line that faces the lower side of the printed circuit board in an inclined direction above the mounting component and on a line that intersects the inclined direction.   The printed circuit board according to claim 1, wherein the convex portion has a mountain shape having an apex at an upper side in the inclination direction.   The printed circuit board according to claim 1, wherein a plurality of the convex portions are formed side by side in the inclined direction.   The in-vehicle apparatus which accommodates the printed circuit board of any one of Claims 1-3, and is installed inclining so that the said printed circuit board may be in the state inclined with respect to the horizontal surface.

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