JPH06231652A - Sheet key switch - Google Patents

Abstract

PURPOSE:To make the sheet key switch in a thin form as well as to eliminate a poor contact, by providing a comb-shape pad on the printed substarte, and a doughnut-type electrode to a membrane sheet, and at the same time, providing a diaphragm having a spherical swelling. CONSTITUTION:A membrane sheet 10 is superposed on a printed substrate 1 through an insulating member 9, and a diaphragm 12 is provided on the sheet 10. To the cutting part of the member 9, a comb-shape pad 5 formed to the substrate 1 is positioned, and a contact electrode 14 opposing to the pad 5 is provided to the sheet 10. When a spherical swelling 15 formed to the diaphragm 12 is pressed, the swelling 15 is turned over and it contacts the electrode 14 of the sheet 10 to the pad 5 by its reverse spherical form. Since the electrode 14 is formed in a doughnut form in this case, the connection between the electrode 14 and the pad 5 is made in a doughnut form, and the contact pattern can obtain a sufficient contact area. Consequently, the low cost can be realized as well as the electron apparatus can be made in a small size and a thin form.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet key switch used for card type or small electronic equipment.

[0002]

2. Description of the Related Art An example of a conventional seat key switch will be described with reference to FIGS.

In the figure, reference numeral 1 is a printed circuit board provided inside a card-type or small electronic device.
A required wiring pattern is formed on the surface of the pad, and a comb-shaped pad 5 as shown in FIG. 6 is provided between the connecting patterns. The comb-shaped pad 5 has comb-shaped connection patterns 5a and 5b. They are formed so as not to come into contact with each other.

Above the comb-shaped pad 5, a rubber key button 3 is provided. The head portion of the key button 3 is exposed by penetrating the front panel 2 of the card-type or small electronic device, and the electrode 4 is heat-welded to the lower surface of the key button 3.

Then, when the key button 3 is pressed, the electrode 4 spans and contacts the connection patterns 5a and 5b of the comb-shaped pad 5 to electrically connect both patterns.

Another conventional example will be described with reference to FIGS. 7 and 8.

A sheet substrate 6 is laid on the printed board 1, and an electrode pad 7 as shown in FIG. 7 is formed on the sheet board 6. The electrode pad 7 has a connection pattern and a printed board via a connector 8. It is connected to the pattern on the 1st side.

The sheet substrate 6 is provided with an insulating material 9, a membrane sheet 10 and a diaphragm 12. An electrode pad 11 is formed at a position facing the electrode pad 7 of the membrane sheet 10, and the electrode pad 11 is formed.
Has a connection pattern, and is connected to the pattern on the printed board 1 side through the sheet board 6 and the connector 8. A portion of the diaphragm 12 corresponding to the electrode 11 bulges upward in a spherical shape. Further, the diaphragm 12 is provided with a rubber sheet-shaped key button 13, and the key button 13 is exposed from the front panel 2.

When the key button 13 is pressed, the bulging portion of the diaphragm 12 is reversed and the electrode pad 11 of the membrane sheet 10 is pressed against the electrode pad 7, and the electrode pad 11 and the electrode pad 7 is connected, and the switch signal at this time is transmitted to the printed board 1 through the connector 8.

[0010]

Among the above-mentioned conventional examples,
In the former case, the movable stroke of the key button 3 itself is large and the device cannot be downsized.
However, there is a problem that it may cause contact failure between the electrode 4 and the comb-shaped pad 5.

Further, of the above-mentioned conventional examples, the latter uses the diaphragm 12, so that the electrode 11 and the electrode pad 7 are in point contact with each other, and are not suitable for the comb-shaped electrode. Further, the printed circuit board 1, the sheet substrate 6, and the membrane sheet 10 are provided, and the electrodes 7 formed on the sheet substrate 6 side and the electrode pads 11 formed on the membrane sheet 10 side are O
Since the structure is such that the N-OFF switch signal is transmitted to the printed circuit board 1 by the connector 8, there are problems such as being complicated and expensive.

In view of the above situation, the present invention intends to provide a very thin sheet key switch which has no contact failure in the electrodes of the comb-shaped pad.

[0013]

SUMMARY OF THE INVENTION According to the present invention, a membrane sheet is provided on a printed circuit board with a required gap therebetween, and a diaphragm is superposed on the membrane sheet, and a pair of connecting members formed in a comb shape on the printed circuit board. Providing comb-shaped pads formed by interposing patterns so as not to contact each other, forming a donut-shaped electrode at a position facing the comb-shaped pad of the membrane sheet, and corresponding to the donut-shaped electrode of the diaphragm. It is characterized in that the portion is bulged to the side opposite to the printed circuit board.

[0014]

When the bulging portion of the diaphragm is pressed, the bulging portion is inverted and the electrodes of the membrane sheet are pressed against the comb-shaped pad, and the pair of connection patterns are brought into conduction at the donut-shaped contact portion.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, the same parts as those shown in FIGS. 5 to 7 are designated by the same reference numerals.

A membrane sheet 10 is superposed on the printed circuit board 1 through an insulating material 9, and a diaphragm 12 is further provided on the membrane sheet 10.

Comb-shaped pads 5 formed on the printed circuit board 1 are located at the cutout portions of the insulating material 9, and the comb-shaped pads 5 are formed.
The contact electrodes 14 facing each other are provided on the membrane sheet 10. The contact electrode 14 is a donut-shaped ring 1.
4a is printed with silver concentrically with the comb-shaped pad 5, and the carbon film 14b further covers the donut-shaped ring 14a including a central portion surrounded by the donut-shaped ring 14a.

In such a structure, the diaphragm 1
When the spherical bulging portion 15 formed on the sheet 2 is pressed, the spherical bulging portion 15 is inverted and the membrane sheet 1 has an inverted spherical shape.
The contact electrode 14 of 0 is brought into contact with the comb pad 5. Since the contact electrode 14 is formed in a donut shape as described above, the contact portion between the contact electrode 14 and the comb-shaped pad 5 has a donut shape as shown in FIG.
For a and 5b, a sufficient contact area can be obtained.

In the above embodiment, the donut-shaped ring 14a may be gold other than silver, for example, and the carbon film 14b may be omitted.

Next, FIGS. 3 and 4 show another embodiment, in which the contact area is further increased as compared with the above-mentioned embodiment.

In the other embodiment, the contact electrodes 14 have the same structure, and a protrusion 16 is formed at the center of the inner surface of the spherical bulging portion 15. When the spherical bulging portion 15 is pressed,
The contact electrode 14 has a portion corresponding to the donut-shaped ring 14a and a portion corresponding to the protrusion 16 concentrically contacting the comb-shaped pad 5.

[0023]

As described above, according to the present invention, the following excellent effects are exhibited.

Since the diaphragm is used, the movable stroke is 1/3 or less as compared with the key button type, and the electronic device can be downsized and thinned.

Since the membrane sheet is brought into direct contact with the comb-shaped pad of the printed circuit board, a connector for signal transmission becomes unnecessary, and the cost can be reduced.

The sheet key switch can be assembled by simply superposing the constituent parts of the sheet key switch, so that the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a contact state of contact electrodes in the embodiment.

FIG. 3 is a cross-sectional view showing the main parts of another embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a contact state of contact electrodes in the other embodiment.

FIG. 5 is a sectional view of a conventional example of a seat key switch.

FIG. 6 is an explanatory diagram of a comb pad that is an example of an electrode pad.

FIG. 7 is an explanatory diagram showing another example of the electrode pad.

8 is a sectional view showing another conventional example of a sheet key switch having the electrode pad of FIG.

[Explanation of symbols]

 1 Printed Circuit Board 5 Comb Pad 10 Membrane Sheet 12 Diaphragm 14 Contact Electrode 15 Spherical Swelling Part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toru Nakata 1 at 100 Nabeta, Toyama City, Toyama Prefecture

Claims (2)

[Claims] 1. A printed circuit board is provided with a membrane sheet with a required gap, and a diaphragm is superposed on the membrane sheet so that a pair of comb-shaped connection patterns formed on the printed circuit board do not come into contact with each other. A comb-shaped pad formed by being inserted is provided, a donut-shaped electrode is formed at a position facing the comb-shaped pad of the membrane sheet, and a portion of the diaphragm corresponding to the donut-shaped electrode is expanded to the side opposite to the printed circuit board. A seat key switch characterized by being released. 2. The sheet key switch according to claim 1, wherein a protrusion is formed on the inner surface of the diaphragm at the center of the bulging portion.