JPH07283554A - Portable electronic equipment - Google Patents

Abstract

PURPOSE:To prevent water from entering the inside of a housing and to suppress increase in cost and deterioration in assembly property for enhancing the waterproofness of a portable electronic equipment by forming the space large between the divided parts of an exterior finish body toward the outside as compared with the inside of the exterior finish body so that water can be constantly guided to the outside of the enclosure. CONSTITUTION:A dimension (b) of an outside opening 6 is made larger than a dimension (a) of an inside opening 5 of a clearance 3 at a part for connecting an upper case 1 and a lower case 2. Since water-drop retention force at the outside opening 6 is smaller than that of the inside opening 5, water drop entering the clearance 3 cannot enter the inside. When the material of a housing is made of ABS, the dimension (a) of the enclosure generated in terms of parts accuracy of the upper case 1 and the lower case 2 is regulated to be 0.3mm or less and the opening 6 outside the housing is regulated to be at least 1mm. By inclining the housing when water enters the clearance 3, the opening 6 first reaches the limit depth for retaining water and water starts to flow from the opening 6, thus preventing water from flooding the inside of the housing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable electronic device having an exterior body having a divided structure.

[0002]

2. Description of the Related Art In recent years, portable electronic devices have come to be used in various fields, and the situation in which the devices are used not only indoors but also outdoors is increasing. Therefore, it is necessary to pay sufficient attention to the waterproof design of the equipment, but most of the equipment has an exterior body with a divided structure. In order to prevent water from entering, conventionally, the gap between the connecting portions has been sealed with a rubber packing or the like. Further, a method has been considered in which the dimensional accuracy of the joint portion is made as strict as possible and the gap is brought close to zero.

[0003]

However, when the rubber packing is used, a new component is incorporated in the housing, which causes problems such as deterioration of assemblability and increase of cost.

Further, it is technically difficult to raise the dimensional accuracy to the limit, and even if it can be realized,
There is a problem that it is difficult to maintain it when considering mass production.

An object of the present invention is to provide a portable electronic device having an exterior body having a novel structure capable of solving the problems inherent in the above-mentioned prior art.

[0006]

Means for Solving the Problems The present inventors have proposed a method for obtaining a high waterproof performance without increasing the dimensional accuracy in the joint portion of the exterior body of the divided structure to an extremely unsuitable level for mass production, Various trials were carried out on a method of obtaining a high waterproof performance without using a sealing member such as a rubber packing in the joint portion, and further, as a result of conducting a study on the principle of water leakage and basic properties of water, It was possible to obtain the result that good waterproof performance can be obtained without making the dimensional accuracy of the connecting portion extremely high and without using rubber packing or the like.

In the portable electronic device according to the present invention,
It was possible to effectively prevent water from entering the inside of the exterior body by configuring the gap between the divided portions of the exterior body to increase from the inside to the outside.

[0008]

In the external body structure of the portable electronic device according to the present invention, as shown in FIG. 1, the outer opening is larger than the dimension a of the inner opening 5 of the gap 3 in the connecting portion between the upper case 1 and the lower case 2. Since the dimension b of the portion 6 is made large, the water droplet holding force in the outer opening portion 6 is smaller than that in the inner opening portion 5, so that the water droplets that have entered the gap 3 do not enter the inside.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of the outer casing of the first embodiment of the portable electronic device according to the present invention and the principle of waterproofing of this outer casing will be described below with reference to FIGS. In FIG.
Reference numeral 1 denotes an outer case, that is, an upper case of the housing, which is connected to the lower case 2. If the gap between the joints of the upper case 1 and the lower case 2 can be set to 0, it is possible to completely prevent the intrusion of water. However, considering the precision of the parts, the gap of the entire joints is 0. Is very difficult to do. Considering the nature of water here, even if water enters a gap,
There are conditions that can stay in the gap due to surface tension and affinity for solids. For example, in the case of ABS resin, in the case of a gap extending in parallel in the vertical direction, the minimum condition that water can enter and stay in the gap is determined by the relation between the width of the gap and the depth of water in the vertical direction.
The relationship is inversely proportional as shown in the graph of FIG. 3 (the width of the gap is x and the depth of water in the vertical direction is y). From the graph of FIG. 3, the thickness of the general housing is 2
When considering ~ 3mm, if this thickness is in the vertical direction,
If the width of the gap is about 2 mm, water will not pass through the gap. However, when considering the usage state of the portable electronic device, the posture of the housing is not constant, and it can be imagined that the casing tilts freely. Considering the case where water has entered the gap between the joints of the casing and the casing is tilted, the water will flow to the lower side of this gap. If there is a part where the gap becomes 0 or is extremely narrow in the middle of this flow, the flowing water will start to accumulate in that part. At this time, depending on the amount of accumulated water, as shown in FIG. 4, the vertical depth (H and J) with respect to the width of the gap becomes considerably deeper than the plate thickness. Therefore, judging from the graph of FIG. 3, when the housing is tilted, the limit depth (y) where water cannot be retained in the gap (x) having a width of 2 mm is immediately reached. Moreover, considering that the housing tilts and water accumulates in the gap,
As can be seen from FIG. 4, the vertical depth of the gap is such that H inside the housing is slightly deeper than J outside the housing. For this reason, when water begins to accumulate, the limit depth at which water can be stored comes earlier in the gap inside the casing than in the gap outside the casing, and there is a high possibility that water will flow into the casing. Become.

In this embodiment, in order to prevent water from entering the inside of the casing due to this phenomenon, a gap 3 that widens toward the outside of the casing is formed in the casing connecting portion as shown in FIG. . When the material of the casing is, for example, the above-mentioned ABS, the dimension a of the opening inside the casing that occurs due to the component accuracy of the upper case 1 and the lower case 2 is restricted to 0.3 mm or less, and The dimension b of the opening 6 is 1 mm or more. With such a structure, if the housing is tilted while water is invading the gap 3, the vertical depth difference between H and J shown in FIG. 4 (the thickness does not exceed the maximum) In consideration of the above, the opening 6 reaches the limit depth at which water can be held first from the graph of FIG. 3, and the water always flows out from the opening 6 outside the housing, so that the inside of the housing is flooded. Will not do.

A second embodiment of the present invention is shown in FIGS. FIG. 6 is a view of the upper case 1 of FIG. 5 viewed from the direction of arrow D. In this embodiment, as shown in FIG.
A rib 4 corresponding to the cross-sectional shape of the gap 3 is provided in the structure so that the gap 3 can be secured even if the upper case 1 and the lower case 2 are slightly deformed. Further, the distance between the ribs 4 can limit the amount of water accumulated in the gap 3. Therefore, H in FIG.
And the depth of J can be suppressed to be shallow, and the width of the opening 5 in FIG.
It is possible to prevent water from entering the housing more easily.

7 and 8 show a third embodiment of the present invention.

FIG. 7 shows the housing connecting portion of this embodiment, and is a sectional view taken along the line EE 'of FIG. 8 (a perspective view of this embodiment).
In this embodiment, as shown in FIG. 7, a lateral opening 8 is provided in the upper case 1, a downward opening 7 is formed between the upper case 1 and the lower case 2, and the f and g surfaces are formed. Perform hydrophilic treatment. The hydrophilic treatment means a treatment in which the f and g surfaces are made different in surface state from each other so that the f and g surfaces are more easily wet with water than the other surfaces.
Here, the wettability of water will be described. As shown in FIG. 9, the contact angle K between the surface 10 and the water droplet 11 stabilizes at a certain angle due to the affinity between the surface 10 and water and the surface tension of water. . As the contact angle K becomes smaller, the height of the water drop becomes lower, so that the surface area of the water drop having the same volume increases and the water drops easily spread. Therefore, in this embodiment, the f and g surfaces in FIG. 7 are coated or coated so that the contact angle of water is small (for example, water repellent to hydrophilic can be obtained by the fluorine treatment). Make it easier to get wet with water than the surface. By such processing, the water that has entered through the opening 8 that faces the outside of the housing advances to the opening 7 that also faces the outside of the housing, and the water that enters through the opening 7 enters the opening 8. I will proceed. For this reason, water does not enter the opening 9 that occurs due to the accuracy of the parts, and it is possible to prevent water from entering the inside of the housing. Of course, the same effect can be obtained by applying a water-repellent coating (increasing the contact angle) to the surface (other than the f and g surfaces) on the opening 9 side.

The contact angle between the surface and water can be changed without coating or painting. Wenzel
According to the above, even if the surfaces are made of the same material, the wettability with respect to the liquid is different between the rough surface and the smooth surface, and the contact angle on the smooth surface is K from FIG. 9, and the apparent contact angle on the rough surface is Let L be K> 90 if K <90 ° K = L if K = 90 ° K <L if K = 90 °, and as the roughness of the surface 10 (actual surface area of the surface) increases The change in the contact angle of the droplet 11 becomes large. In this example, the surface 10 was made of the same ABS resin as that of Example 1, and the droplet 11 was made water. As a result, K = 77.7 °.
From the above equation, it can be seen that the contact angle of the droplet 11 becomes smaller when the surface 10 is roughened. The rough surface state of 1 has a groove-shaped rough surface and a projection-shaped rough surface, and the Wenzel's formula is applied to the groove-shaped rough surface. Therefore, by roughening the f and g surfaces in FIG. 7 into grooves, the same effect as that obtained by coating or painting can be obtained.

[0015]

As described above, according to the present invention,
Water can be prevented from entering the inside of the housing by making the gap between the joined parts of the divided construction into a shape in which water is always guided to the outside of the housing. There is an effect that the waterproof property of the portable electronic device can be improved by suppressing the rise of the battery and the deterioration of the assembling property.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of a divided portion of an exterior body of a portable electronic device according to a first embodiment of the present invention, which is an enlarged sectional view of a portion A in FIG.

FIG. 2 is a transverse cross-sectional view of the exterior body of the divided structure of the portable electronic device according to the first embodiment of the present invention.

FIG. 3 is a graph showing a water droplet holding capacity in a gap having a width x and a depth y.

FIG. 4 is an enlarged cross-sectional view when water is accumulated in a gap between housing (exterior body) coupling portions.

FIG. 5 is an enlarged cross-sectional view of a joint portion of an exterior body of a portable electronic device according to a second embodiment of the present invention.

FIG. 6 is a partially enlarged front view of the exterior body having the structure shown in FIG. 5 as seen from the outside.

FIG. 7 is an enlarged cross-sectional view of a coupling portion in an exterior body of a portable electronic device of a third embodiment of the present invention, which is a cross-sectional view taken along the line EE ′ of FIG.

FIG. 8 is a perspective view of a part of an exterior body of a portable electronic device of a third embodiment of the invention.

FIG. 9 is a diagram for explaining a Wenzel's equation regarding a droplet and a surface.

[Explanation of Codes] 1 ... Upper case 2 ... Lower case 3 ... Gap 4 ... Rib 5 ... Inner opening of the gap 6 ... Outer opening of the gap 7, 8 ... Outer opening 9 ... Inner opening Part 10 ... Surface 11 ... Droplet

Claims (3)

[Claims] 1. A portable electronic device having an exterior body having a divided structure, characterized in that a gap between divided portions of the exterior body is configured to become larger from the inside to the outside of the exterior body. Portable electronic device. 2. The portable electronic device according to claim 1, wherein a rib for securing the gap is provided inside or outside the gap of the divided portion of the exterior body. 3. A portable electronic device having an exterior body having a divided structure, wherein at least two outer openings communicating with an inner opening of the exterior body are provided in the divided portion of the exterior body, and the outer opening is provided. The portable electronic device is characterized in that the inner wall surface of the part is configured as a surface through which water is more easily transmitted than other wall surfaces.