JPH0646026Y2 - Dustproof structure of membrane keyboard - Google Patents

Description

[Detailed Description of the Invention] [Industrial application] The present invention relates to a dustproof structure of a membrane keyboard, and more particularly to a dustproof structure of a membrane keyboard in which an attachment position of an air vent hole is improved.

[Prior Art] FIGS. 2 (A) to (C) and FIGS. 3 to 5 show a conventional membrane keyboard, and FIG. 2 (A) is an exploded perspective view thereof. (B) is a plan view, FIG. 2 (C) is an enlarged sectional view, and FIGS. 3 and 4 are enlarged sectional views in an operating state.
FIG. 5 is a cross-sectional view of a dust infiltration state.

The membrane keyboard consists of the top sheet 1, spacers 2,
The lower sheet 3, the adhesive sheet 4, and the bracket 5 are bonded together. As shown in FIG. 2, on the lower surface of the upper sheet 1 and the upper surface of the lower sheet 3, conductive patterns each having an upper electrode 6 and a lower electrode 7 are juxtaposed and printed. In the conductive pattern, wide electrodes are connected by a narrow conductive portion. The upper electrode 6 and the lower electrode 7 are arranged so as to face each other. The spacer 2 interposed between the sheets 1 and 3 holds the gap between the electrodes 6 and 7, and
When a spacer space 11 is provided around 7 and the switch pressing surface of the upper sheet 1 is pressed as shown in FIG. 2 (C), the electrode 6 comes into contact with the electrode 7 and is turned on.

By the way, when the material of the membrane keyboard is polyester film, if the spacer space 11 is completely sealed,
As shown in FIG. 3, the electrodes 6, 7 are affected by a sudden temperature change.
May come into contact.

Therefore, as shown in FIG. 2 (C) and FIG. 4, the air vent holes 8, 9 and 10 communicating from the spacer space 11 to the outside are provided in the lower sheet 3, the adhesive sheet 4 and the bracket 5, respectively, and the spacer The inner pressure of the space 11 is always the same as the outer pressure.

[Problems to be Solved by the Invention] In a conventional membrane keyboard, one end of the air vent hole is provided in the bracket 5, and the other end of the air vent hole is provided around the electrodes 6 and 7. Therefore, as shown in FIG. 5, every time the key switch is pressed, the dust 12 is mixed with the inflowing outside air around the electrodes 6 and 7, and the dust contained in the outside air is attracted to the high voltage generated in the electrodes. The contact resistance increases due to accumulation between the electrodes 6 and 7, and in the worst case, contact failure may occur.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a dust structure of a membrane keyboard that prevents dust from inflowing from the outside and cannot reach the electrode position even if there is dust inflow. It is in.

[Means for Solving the Problems] In order to achieve the above object, according to the present invention, an upper portion formed by arranging a conductive pattern having a wide upper electrode and a narrow conductive portion on a back surface of a switch pressing surface in parallel. A sheet, a lower sheet formed by arranging a conductive pattern having a wide lower electrode facing the upper electrode and a narrow conductive portion on the upper surface, and both electrodes interposed between the sheets. Spacers each having a spacer space around the electrode that holds a space between them and connected by connection holes, and an adhesive sheet in which a bracket is adhered to a lower surface and an upper surface is adhered to a lower surface of a lower sheet are provided. In the dustproof structure of the membrane keyboard with the air vent holes connecting the bottom sheet, the adhesive sheet, and the bracket arranged so that the air vent holes face the connection holes and do not overlap the conductive parts. The air vent hole provided in the lower sheet, the air vent hole provided in the bracket at a position not overlapping the spacer space and the connection hole, and the air vent hole in the lower sheet and the bracket air vent hole provided in the adhesive sheet. It has a communication hole for communication.

[Operation] When the switch pressing surface of the membrane keyboard configured as described above is pressed, the air in the spacer space is released to the outside through the spacer space, the air vent hole of the lower sheet, the communication hole, and the air vent hole of the bracket. Is released. When the finger is released from the switch pressing surface, the outside air flows into the spacer space through the air vent hole of the bracket, the communication hole, and the air vent hole of the lower sheet. At this time, dust also flows in together with the outside air, but the dust does not reach the electrode position because it adheres to the communication hole, the periphery of the air vent hole of the lower sheet, and the inner surface of the connection hole.

[Embodiment] An embodiment of the present invention will be described with reference to the drawings.
Elements common to the drawings are given the same reference numerals.

1 (A) to 1 (D) show a membrane keyboard to which the dustproof structure of the present invention is applied. FIG. 1 (A) is an exploded perspective view thereof, and FIG. 1 (B) is a plan view. Figure, first
Figures (C) and (D) are respectively C-C lines in Figure 1 (B),
It is an expanded sectional view which follows the DD line.

The membrane keyboard, as shown in Fig. 1 (A),
It is composed of an upper sheet 1, a spacer 2, a lower sheet 3, an adhesive sheet 4 and a bracket 5, and plan views of the respective sheets are shown in FIGS. 6 to 9. On the lower surface of the upper sheet 1, that is, the back surface of the switch pressing surface, a conductive pattern having an upper electrode 6 is formed by printing as shown by a broken line in FIG. The conductive pattern connects the wide upper electrodes 6 with a narrow conductive portion. Also on the upper surface of the lower sheet 3,
As shown by the solid line in FIG. 1 (A), a conductive pattern having the lower electrode 7 is formed by printing, and is arranged in parallel as shown in FIG. Since the upper electrode 6 and the lower electrode 7 are arranged to face each other to form a key switch, a conductive pattern is also provided in parallel on the upper sheet 1. The spacer 2 interposed between the upper sheet 1 and the lower sheet 3 is
As shown in FIGS. 1 (C), (D) and FIG. 6, a gap between the electrodes 6 and 7 is maintained and a spacer space 11 is provided around the electrodes 6 and 7. The four spacer spaces 11 are connected in the longitudinal direction by four elongated connecting holes 11a, and are provided so that the spacers 2 do not contact the conductive patterns of the upper sheet 1 and the lower sheet 3.

As shown in FIG. 7, the lower sheet 3 is provided with an air vent hole 18 so as to face the connection hole 11a and not to overlap the conductive portion. Further, as shown in FIG. 8, the adhesive sheet 4 is provided with a long hole-shaped communication hole 19 at a position overlapping with the air vent hole 18 of the lower sheet 3. Further, as shown in FIGS. 1B and 9, the bracket 5 is provided with an air vent hole 20 at a position overlapping the communication hole 19 but not the spacer space 11 and the connection hole 11a. . That is, the communication hole 19 connects the air vent hole 18 of the lower sheet 3 and the air vent hole 20 of the bracket 5.

As shown in FIG. 1 (A), the respective sheets thus constructed are bonded in the order of the bracket 5, the adhesive sheet 4, the lower sheet 3, the spacer 2 and the upper sheet 1 to complete the membrane keyboard, and the key switch portion. The cross-sections are as shown in FIGS. 1 (C) and (D).

Next, the operation will be described. When a key is pressed, the upper sheet 1 bends, the upper electrode 6 comes into contact with the lower electrode 7 and a current is conducted, and the switch is turned on. At this time, the spacer space 11
The air inside is connected to the connection hole 11a, the air vent hole 18 of the lower sheet 3,
It is discharged to the outside through the communication hole 19 and the air vent hole 20 of the bracket 5.

Then, when the finger is released from the key, the upper sheet 1 becomes flat, the upper electrode 6 is separated from the lower electrode 7, and the outside air is exposed to the air vent hole 20, communication hole 19 and lower sheet 3 of the bracket 5.
The air flows into the spacer space 11 through the air vent hole 18 and the connection hole 11a. At this time, although dust also flows in, outside air reaches the connection hole 11a through the air vent hole 20 of the lower sheet 3, the communication hole 19, and the air vent hole 18 of the lower sheet 3, and then the spacer space having the electrodes 6 and 7. As it reaches 11, dust will pass through the communication hole 19,
The air bleeding hole 18 of the lower sheet, the upper sheet of the connection hole 11a and the inner surface of the lower sheet 3 are attached and removed. Particularly, when passing through the narrow air vent hole 18 and the air vent hole 20, a Karman vortex is generated to attach dust to the inner surfaces of the lower sheet 3 and the bracket 5 around the hole mouth.

In the embodiment, the adhesive sheet 4 has a large hole-like communication hole 19
However, the communication hole 19 may have any other shape as long as it can communicate the air vent hole 18 provided in the lower sheet 3 and the air vent hole 20 provided in the bracket 5.

[Effects of the Invention] As described in detail above, the present invention provides an upper sheet formed by juxtaposing a conductive pattern having a wide upper electrode and a narrow conductive portion on a back surface of a switch pressing surface, and an upper sheet. A lower sheet formed by arranging a conductive pattern on the upper surface of a conductive pattern having a wide lower electrode facing the electrode and a narrow conductive portion, and a gap between the two electrodes interposed between the two sheets. Air for connecting the spacer space and the outside is provided with spacers each having a spacer space that is held and connected by a connection hole around the electrode, and an adhesive sheet that has a bracket attached to the lower surface and an adhesive sheet attached to the lower surface of the lower sheet on the upper surface. In the dustproof structure of the membrane keyboard where the vent holes are arranged in the lower sheet, adhesive sheet, and bracket, the air vent holes are installed in the lower sheet so that they do not overlap the conductive parts facing the connection holes. The air vent hole, the air vent hole provided in the bracket at a position not overlapping the spacer space and the connection hole, and the communication hole provided in the adhesive sheet for communicating the air vent hole of the lower sheet with the air vent hole of the bracket. From having
Without impairing the function of the conventional air vent hole, it is possible to prevent the contact failure of the electrodes and the increase of the contact resistance due to the inclusion of dust.

[Brief description of drawings]

1 (A), (B), (C) and (D) show a membrane keyboard to which the dustproof structure of the present invention is applied.
FIG. 1A is an exploded perspective view thereof, FIG. 1B is a plan view, and FIGS. 1C and 1D are CC of FIG. 1B, respectively.
Line, an enlarged cross-sectional view along the line D-D, FIG. 2 (A),
(B), (C), FIGS. 3 to 5 show a conventional membrane keyboard, FIG. 2 (A) is an exploded perspective view thereof, FIG. 2 (B) is a plan view, and FIG. C) is an enlarged sectional view, third
FIGS. 4 and 5 are enlarged cross-sectional views of an operating state, FIG. 5 is a cross-sectional view of a dust invading state, FIG. 6 is a plan view of a spacer, FIG. 7 is a plan view of a lower sheet, and FIG. 8 is a plan view of an adhesive sheet. A plan view and FIG. 9 are plan views of the bracket. 1 ... Upper sheet, 2 ... Spacer, 3 ... Lower sheet, 4 ...
Adhesive sheet, 5 ... Bracket, 6 ... Upper electrode, 7 ... Lower electrode, 11 ... Spacer space, 11a ... Connection hole, 12 ... Dust, 18
… Lower seat air vent hole, 19… communication hole, 20… bracket air vent hole.

Claims (2)

[Scope of utility model registration request] 1. An upper sheet formed by juxtaposing a conductive pattern having a wide upper electrode and a narrow conductive portion on the back surface of a switch pressing surface, and a wide lower electrode facing the upper electrode and a narrow width. A lower sheet formed by arranging a conductive pattern having a conductive portion on the upper surface, and a spacer space interposed between the two sheets to maintain a gap between the electrodes and connect with a connecting hole to form an electrode. Each of which has a spacer around it and an adhesive sheet in which a bracket is adhered to the lower surface and the upper surface is adhered to the lower surface of the lower sheet, and air vent holes for connecting the spacer space and the outside are arranged in the lower sheet, the adhesive sheet, and the bracket. In the dustproof structure of the provided membrane keyboard, the air vent hole is provided in the lower sheet so as to face the connection hole and not overlap the conductive portion,
An air vent hole provided in the bracket at a position not overlapping the spacer space and the connection hole, and a communication hole provided in the adhesive sheet for communicating the air vent hole of the lower sheet and the air vent hole of the bracket. Dustproof structure of the membrane keyboard. 2. The dustproof structure for a membrane keyboard according to claim 1, wherein the communication hole is a long hole shape communicating with the air vent holes of the plurality of lower sheets.