JP2001229776A - Membrane switch and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a membrane switch excellent in water-proof, drip-proof and also dust-proof performance. SOLUTION: In the membrane switch, a spacer part 30 is inserted between an upper circuit board 10 and a lower circuit board 20, and the spacer part 30, the upper circuit board 10 and the lower circuit board 20 are stuck to each other with an adhesive layer 50. In addition, a primer processing layer 70 is applied to the surface of the spacer part. Therefore, the adhesion between the adhesive layer and the spacer part can be improved, and the membrane switch excellent in water-proof, drip-proof, and also dust-proof performance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane switch used for a keyboard of a computer or an input switch of various electronic devices or devices, and more particularly to a switch having improved waterproofness.

[0002]

2. Description of the Related Art The structure of a membrane switch is roughly shown in FIGS. 2 and 3, and a sheet-like upper circuit board 10, a lower circuit board 20, and a spacer sheet 30 interposed therebetween. Upper circuit board 1
Electrodes 11 and 21 are provided on opposing inner sides of the 0 and lower circuit boards 20 at appropriate positions. On the other hand, a part of the spacer sheet 30 corresponding to this part is removed, and a switch chamber (electrode chamber) of the space is formed. 31, these two electrodes 11,
A switching operation can be obtained by contact and non-contact of 21.

The upper circuit board 10 and the lower circuit board 20
The spacer sheet 30 is generally made of a plastic film such as polyethylene terephthalate, and the electrodes 11, 21 and necessary circuits are formed by a printing method such as silver, copper paste, or solder. Here, the spacer sheet 30 is for preventing the electrodes 11 and 21 from contacting in a normal state, and may be formed not only by such a sheet but also by a method such as printing. .

On the other hand, in the case of a membrane switch having such a structure, the periphery of each of the substrates 10, 20 and the sheet 30 and the periphery of the through hole 40 penetrated through the switch itself for waterproof, drip-proof and dust-proof. Each part is adhered to each other by an adhesive layer 50 such as an adhesive paste, and has a sealed structure to prevent water and dust from entering the switch chamber 31 in particular. In the figure, reference numeral 60 denotes an air vent hole.

[0005]

However, due to the recent miniaturization of keyboards and electronic devices, the width of the adhesive portion between the spacer sheet 30 and the upper circuit board 10 or the lower circuit board 20, that is, the width of the adhesive layer 50 is reduced. While the width is reduced, there is a portion where the width is about 0.5 mm in some parts, and there is a problem that adhesion failure is likely to occur in this portion.

The present invention has been made in view of such conventional problems, and a primer treatment layer is applied to the surface of a spacer portion such as a spacer sheet to improve the adhesiveness with an adhesive. An object of the present invention is to provide a membrane switch and a method for manufacturing the same, which suppress occurrence of adhesion failure.

[0007]

According to the first aspect of the present invention, a spacer is interposed between an upper circuit board and a lower circuit board, and the spacer is connected to the upper circuit board and the lower circuit board. In a membrane switch bonded by an adhesive layer, a primer treatment layer is applied to the surface of the spacer portion.

According to a second aspect of the present invention, a spacer is interposed between an upper circuit board and a lower circuit board, and the spacer is adhered to the upper circuit board and the lower circuit board by an adhesive layer. In the method for manufacturing a membrane switch, a primer material is applied to the surface of the spacer portion, and the upper circuit board or the lower circuit board is assembled and thermally laminated with the adhesive layer interposed therebetween. A method for manufacturing a membrane switch.

According to a third aspect of the present invention, after the thermal lamination, further heat treatment is performed.
In the method for manufacturing the membrane switch described above.

[0010]

FIG. 1 shows a part of an embodiment of a membrane switch according to the present invention, and its entire structure is substantially the same as that of the membrane switch shown in FIGS. There is a structure. Therefore, FIGS.
The same components as those of the membrane switch are denoted by the same reference numerals.

That is, in the present embodiment, the surface of the spacer portion 30 made of a spacer sheet or the like
0 so that the primer-treated layer 70 and the pressure-sensitive adhesive layer 50 are well bonded. In addition, the spacer portion 30 includes one formed by a method such as printing, in addition to the case using the spacer sheet.

As the primer material of the primer-treated layer 70, it is preferable to use a curable resin ink that is compatible with the adhesive of the adhesive layer 50. More specifically, since urethane-based, polyester-based, and acrylic-based materials are usually used as the pressure-sensitive adhesive, in response to this, the primer material may be a urethane-based ink, a polyester-based ink, or an acrylic-based ink. .

This primer material is applied to the surface of the spacer portion 30 at the time of manufacturing, and then the upper circuit board 10 or the lower circuit board 20 is assembled with the adhesive layer 50 interposed therebetween, and these are integrated by heating. A heat lamination process for bonding is performed. This makes them compatible with each other,
Primer treatment layer 70 and pressure-sensitive adhesive layer 50 on spacer surface
Therefore, even if the width of the pressure-sensitive adhesive layer 50 is as small as about 0.5 mm, a good adhesive force can be obtained. In other words, in other words, a membrane switch having excellent waterproof, drip-proof, and dust-proof properties can be obtained.

After the above-mentioned heat laminating treatment, if necessary, post-treatment by heating may be performed. by this,
Since the pressure-sensitive adhesive is completely cured, a membrane switch with further improved adhesiveness can be obtained.

(Examples 1 to 6, Comparative Example 1) A 75 μm polyethylene terephthalate film is used for both the upper circuit board, the lower circuit board, and the spacer sheet of the spacer section, and the overall structure is as shown in FIGS. And a primer treatment layer as shown in FIG. 1 was provided on the surface of the spacer portion, and the pattern width of the pressure-sensitive adhesive layer was 0.6 mm and the pattern thickness of the pressure-sensitive adhesive was 15 μm. A sample membrane switch having a circuit pattern thickness of 8 μm was manufactured under the conditions shown in Table 1.

Each of these membrane switches (Example 1)
６，6 and Comparative Example 1) were subjected to a short circuit test by water immersion. That is, the entire switch is immersed in a water depth of 2 mm. At this time, normal water and hot water of 60 ° C. are used as the water for 1 hour, 4 hours, 12 hours, and 24 hours. The presence or absence was determined. In addition, each of these tests prepared five samples about each example, and performed each five times. And, when there is no short circuit, it is indicated by ○, and when there is a short circuit, it is indicated by ×.

For reference, a polyethylene terephthalate film corresponding to an upper circuit board or a lower circuit board and a polyethylene terephthalate film provided with a primer treatment layer corresponding to a spacer sheet of a spacer portion were subjected to the conditions shown in Table 1. Examples 1 to 6 were laminated according to Comparative Example 1), and a peel test for determining the adhesive strength between these laminated films was also performed. And, when the adhesive strength was extremely good, it was indicated by ◎, when it was good, it was indicated by ○, and when it was good, it was indicated by △.

[0018]

[Table 1]

As shown in Table 1, in the case of the membrane switch according to the present invention (Examples 1 to 6), even when immersed in water for 1 hour to 24 hours, there is no short circuit between the electrodes from normal temperature to 60 ° C. hot water. It can be seen that a stable operation can be obtained. On the other hand, in the case of the membrane switch lacking the requirements of the present invention (Comparative Example 1), it can be seen that there is a short circuit between the electrodes when hot water is immersed for a long time, and stable operation cannot be obtained. In the case of the membrane switch according to the present invention (Example 1)
In Examples 6 to 6, the peel strength is good, whereas the membrane switch lacking the requirements of the present invention is used (Comparative Example 1).
Can be seen to be slightly defective.

[0020]

As is clear from the above description, according to the membrane switch of the present invention, since the surface of the spacer portion is provided with the primer-treated layer, the adhesion between the pressure-sensitive adhesive layer and the spacer portion can be improved. As a result, a membrane switch having excellent waterproof, drip-proof, and dust-proof properties can be obtained.

Further, according to the method of manufacturing a membrane switch according to the present invention, the primer-treated layer can be easily implemented because it is only necessary to apply a primer material to the surface of the spacer portion and then heat laminate. At this time, if necessary, a heat treatment is performed after the heat lamination, whereby the curing of the pressure-sensitive adhesive is further promoted, and a more excellent membrane switch can be manufactured.

[Brief description of the drawings]

FIG. 1 is a partially enlarged longitudinal sectional view showing a part of an example of a membrane switch according to the present invention.

FIG. 2 is a schematic plan view showing a part of the membrane switch.

FIG. 3 is a cross-sectional view of the membrane switch of FIG.
It is a line longitudinal cross-sectional view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Upper circuit board 20 Lower circuit board 30 Spacer part (spacer sheet) 50 Adhesive layer 70 Primer processing layer

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Nobuyuki Sasaki 1400, Misaki, Sakura City, Chiba Prefecture Fujikura Sakura Works F-term (reference) 5G006 AA01 FB14 FD03 FD04 5G023 CA19 CA21

Claims (3)

[Claims] 1. A membrane switch comprising a spacer part interposed between an upper circuit board and a lower circuit board, and the spacer part being bonded to the upper circuit board and the lower circuit board by an adhesive layer. A membrane switch characterized in that a primer treatment layer is applied to a surface of a spacer portion. 2. A method for manufacturing a membrane switch, comprising a spacer part interposed between an upper circuit board and a lower circuit board, and the spacer part being bonded to the upper circuit board and the lower circuit board by an adhesive layer. 3. The method for manufacturing a membrane switch according to claim 1, wherein a primer material is applied to a surface of the spacer portion, and the upper circuit board or the lower circuit board is assembled and thermally laminated with the adhesive layer interposed therebetween. 3. The method for manufacturing a membrane switch according to claim 2, further comprising a heat treatment after the heat lamination.