JP2016091796A - Membrane switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a membrane switch that can be suppressed from turning ON unexpectedly.SOLUTION: A membrane switch 1 is such that an inner edge part 521 of a lower surface 523 in plan view of a rubber dome 5 is positioned more on the side of a center C of an opening part 20 than an edge part 431 of an upper adhesive layer 43 positioned at a periphery of an opening part 20 of a spacer 2, an upper gap 203 formed as the edge part 431 is positioned outside the opening part 20 is provided at an overlap part between the spacer 2 and an upper sheet 4 in a region that the lower surface 523 occupies in plan view, and an upper thickness increasing member 45 is provided at the upper gap 203.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a membrane switch.

  A membrane switch is known in which contacts between electrodes facing each other through an opening of a spacer plate are arranged at a position corresponding to a key (see, for example, Patent Document 1).

JP 2012-129140 A

  In a notebook computer equipped with a keyboard constructed by attaching a rubber dome that is elastically deformed by pressing force on the top of the membrane switch as described above, the electrodes of the membrane switch approach each other even when no pressure is applied. There is a problem that the membrane switch may be turned on unexpectedly.

  The problem to be solved by the present invention is to provide a membrane switch that can suppress unexpectedly turning on.

[1] A membrane switch according to the present invention includes a spacer having an opening and a first electrode provided corresponding to the opening, and one main surface of the spacer via a first adhesive layer And a second electrode provided so as to face the first electrode through the opening, and the other main portion of the spacer through the second adhesive layer. A second sheet provided on the surface, and a pressing force applied to the first sheet or the second sheet via a rubber dome having a mounting portion corresponding to a peripheral edge of the opening. In the membrane switch in which the first electrode and the second electrode are brought into contact with each other, the inner edge portion of the attachment portion in a plan view is the first adhesive layer located around the opening. Located closer to the center of the opening than the edge of 1. In the area occupied by the mounting portion in plan view, the first edge formed on the overlapping portion of the spacer and the first sheet is located outside the opening. Gap is provided,
The first gap is provided with a first thickening member.

  [2] In the above invention, the first thickening member may be provided on the first sheet.

  [3] In the above invention, an end of the first thickening member on the center side of the opening may extend inside the opening.

  [4] In the above invention, the first thickening member may be formed integrally with the first electrode.

  [5] In the above invention, the first thickening member may be formed independently of the first electrode.

  [6] In the above invention, a plurality of the first thickening members arranged apart from each other may be provided on the first sheet.

  [7] In the above invention, the outer edge portion of the attachment portion in a plan view may be located closer to the center of the opening than the first edge portion.

  [8] In the above invention, the inner edge portion of the attachment portion in plan view is located closer to the center of the opening portion than the second edge portion of the second adhesive layer located around the opening portion. In the region occupied by the attachment portion in plan view, the second edge portion is formed by the second edge portion being located outside the opening portion at the overlapping portion of the spacer and the second sheet. A second thickening member may be provided in the second gap.

  According to the present invention, the inner edge of the rubber dome mounting portion in plan view is located closer to the center of the opening than the first edge of the first adhesive layer positioned around the opening of the spacer. ing. Further, in a region occupied by the attachment portion in plan view, a first gap is provided in an overlapping portion between the spacer and the first sheet, and a first thickening member is provided in the first gap. It has been. Thereby, even if the pressure is not applied, it can prevent that the electrodes of a membrane switch will approach, and it can suppress that a membrane switch will be in an ON state unexpectedly.

FIG. 1 is a cross-sectional view showing a membrane switch according to an embodiment of the present invention. FIG. 2 is a plan view showing the inner surface of the first sheet constituting the membrane switch in the embodiment of the present invention. FIG. 3 is a plan view showing the inner surface of the second sheet constituting the membrane switch in the embodiment of the present invention. 4 (A) and 4 (B) are plan views showing a modification of the second sheet constituting the membrane switch in the embodiment of the present invention, and FIG. 4 (A) is a first modification. FIG. 4B shows a second modification. FIG. 5 is a sectional view showing a modification of the membrane switch in the embodiment of the present invention. FIG. 6 is a cross-sectional view showing another modification of the membrane switch in the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a sectional view showing a membrane switch in the present embodiment, FIG. 2 is a plan view showing the inner surface of a lower sheet (second sheet) constituting the membrane switch in the present embodiment, and FIG. It is a top view which shows the inner surface of the upper sheet | seat (1st sheet | seat) which comprises the membrane switch in a form, FIG. 4 (A) and FIG. 4 (B) are the 1st of the upper sheet | seat which comprises the membrane switch in this embodiment. And FIG. 5 is a cross-sectional view showing a modification of the membrane switch in the present embodiment.

  The membrane switch 1 in this embodiment is an input switch used for a keyboard of a notebook personal computer, for example, and includes a spacer 2, a lower sheet 3, and an upper sheet 4 as shown in FIG. A rubber dome 5 is attached to the upper part of the upper sheet 4. The use of the membrane switch 1 is not particularly limited.

  The spacer 2 is a sheet-like member having a predetermined thickness, and is formed of a flexible insulating material such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN). Yes. The spacer 2 has a circular opening 20 for electrodes 31 and 41 (both described later) to face each other. The shape of the opening 20 is not particularly limited as long as it is a shape surrounding the lower electrode 31 and the upper electrode 41 in plan view as shown in FIGS. 2 and 3. For example, the opening 20 may be rectangular or the like in plan view.

  The lower main surface 21 of the spacer 2 is provided with a lower sheet 3 via a lower adhesive layer 33, and the upper main surface 22 of the spacer 2 is provided with an upper sheet 4 via an upper adhesive layer 43. Yes. The upper main surface 22 of the spacer 2 in the present embodiment corresponds to an example of one main surface of the present invention, and the lower main surface 21 of the present invention corresponds to an example of the other main surface.

  The lower sheet 3 is made of a flexible insulating material such as polyethylene terephthalate or polyethylene naphthalate. The lower adhesive layer 33 is provided between the spacer 2 and the lower sheet 3 on substantially the entire surface excluding the peripheral edge 201 of the opening 20 of the spacer 2, and the lower edge 331 of the lower adhesive layer 33 is a flat surface. It is located around the opening 20 in view. Thus, a lower gap 202 is formed between the spacer 2 and the lower sheet 3 at the peripheral edge 201 of the opening 20.

  Further, as shown in FIG. 2, the main surface 32 of the lower sheet 3 in the present embodiment is provided with a lower electrode 31 and a lead wiring 34 connected to the lower electrode 31. The lower electrode 31 and the lead-out wiring 34 are formed by printing and curing a conductive paste such as a silver paste or a copper paste on the main surface 32 of the lower sheet 3. Examples of such printing methods include screen printing, gravure offset printing, and inkjet printing. In the present embodiment, the lower electrode 31 and the lead-out wiring 34 are integrally formed, but they may be formed separately.

  As shown in FIG. 2, the outer shape of the lower electrode 31 is a circular shape having a smaller diameter than the opening 20 of the spacer 2, and is provided at a position corresponding to the opening 20 of the spacer 2. That is, in plan view, the center of the lower electrode 31 and the center of the opening 20 of the spacer 2 substantially coincide with each other. The “center” indicates a point corresponding to the center of gravity in the planar shape. The shape of the lower electrode 31 is not particularly limited to the above. For example, the outer shape of the lower electrode may be rectangular, mesh, or comb-like.

  Similarly to the lower sheet 3, the upper sheet 4 is also made of a flexible insulating material such as polyethylene terephthalate or polyethylene naphthalate. The upper adhesive layer 43 is provided between the spacer 2 and the upper sheet 4 on substantially the entire surface excluding the peripheral edge 201 of the opening 20 of the spacer 2, and the upper edge 431 of the upper adhesive layer 43 is a flat surface. It is located around the opening 20 in view. Thereby, an upper gap 203 is formed between the spacer 2 and the upper sheet 4 at the peripheral edge 201 of the opening 20.

  Further, as shown in FIG. 3, the main surface 42 of the upper sheet 4 in the present embodiment is provided with an upper electrode 41 and a lead wiring 44 connected to the upper electrode 41. The upper electrode 41 and the lead wiring 44 are provided by the same material and method as the lower electrode 31. In the present embodiment, the upper electrode 41 and the lead-out wiring 44 are integrally formed, but they may be formed separately.

  As shown in FIG. 3, the outer shape of the upper electrode 41 has a circular shape similar to that of the lower electrode 31, and is provided at a position corresponding to the opening 20 of the spacer 2. That is, in the plan view, the center of the upper electrode 41 and the center of the opening 20 of the spacer 2 substantially coincide with each other. The shape of the upper electrode 41 is not particularly limited to the above. For example, the outer shape of the upper electrode may be rectangular, mesh, or comb-like.

  As shown in FIGS. 1 and 3, an upper thickening member 45 is provided around the upper electrode 41 on the main surface 42 of the upper sheet 4 of the present embodiment. The upper thickening member 45 in this embodiment is provided on the upper sheet 4 by the same material and method as the upper electrode 41. The height (thickness) of the upper thickening member 45 is not less than the height (thickness) of the upper electrode 41 and not more than the height (thickness) of the upper adhesive layer 43. At least a portion is provided in the upper gap 203. Further, the end 451 on the opening 20 side of the spacer 2 in the upper thickening member 45 extends to the inside of the opening 20, and the upper thickening member 45 and the opening 20 overlap in plan view. . The material constituting the upper thickening member 45 is not particularly limited to the above. For example, the upper thickening member 45 may be made of an insulating material. Although not particularly illustrated, the upper thickening member 45 may be provided on the upper main surface 22 of the spacer 2. The end 451 of the upper thickening member 45 in the present embodiment corresponds to an example of the “end on the center side of the opening” in the present invention.

  Further, the upper sheet 4, the upper adhesive layer 43, the upper electrode 41, the upper edge 431, the upper gap 203, and the upper thickening member 45 in the present embodiment are the first sheet, the first adhesive layer, It corresponds to an example of the first electrode, the first edge, the first gap, and the first thickening member, respectively, and the lower sheet 3, the lower adhesive layer 33, the lower electrode 31, and the lower edge in the present embodiment. 331 and the lower gap 202 correspond to examples of the second sheet, the second adhesive layer, the second electrode, the second edge, and the second gap of the present invention, respectively.

  In the present embodiment, a plurality of (in this example, four) upper thickening members 45 are provided so as to surround the upper electrode 41 at a certain distance, and these upper thickening members 45 are planarly viewed. Are arranged on the edge of the opening 20 of the spacer 2 at substantially equal intervals. Each of the upper thickening members 45 has an elliptical shape or a generally slender shape that gently curves toward the center of the upper electrode 41. The number of upper thickening members 45 provided on the upper sheet 4 and the arrangement and shape of the upper thickening members 45 are not particularly limited. For example, the outer shapes of the plurality of upper thickening members 45 may be different from each other.

  Further, for example, as shown in FIG. 4A, two upper thickening members 45 </ b> B may be provided on the main surface 42 of the upper sheet 4. In the example of FIG. 4A, the upper thickening member 45B has a perfect circular outer shape having a diameter smaller than the diameter of the upper electrode 41, and the lead wiring 44 is sandwiched between the centers C of the upper electrode 41. It is provided on the opposite side. Further, the two upper thickening members 45B are arranged at line-symmetrical positions with the extending direction of the lead wiring 44 as the center, and the edge of the opening 20 of the spacer 2 is the upper thickening member 45B in plan view. It is arranged so as to overlap with the approximate center.

  Further, for example, as shown in FIG. 4B, the upper electrode 41 may be continuous with the upper thickening member 45C, and they may be integrally formed from the same material. Although not particularly illustrated, for example, only a part of the plurality of upper thickening members 45 is formed integrally with the upper electrode 41, and the other upper thickening members 45 are formed independently of the upper electrode 41. May be. Further, a part of the upper thickening member 45 may be connected to each other.

  In the present embodiment, the upper thickening member 45 is provided only on the main surface 42 of the upper sheet 4, but the present invention is not particularly limited thereto. For example, although not particularly illustrated, a lower thickening member may be provided only on the main surface 32 of the lower sheet 3. In this case, the lower thickening member is provided in the lower gap 202 formed between the peripheral edge 201 of the opening 20 of the spacer 2 and the main surface 32 of the lower sheet 3. In this case, the lower sheet 3, the lower adhesive layer 33, the lower electrode 31, the lower edge portion 331, the lower gap 202, and the lower thickening member are the first sheet, the first adhesive layer, and the first electrode of the present invention. , Corresponding to an example of the first edge, the first gap, and the first thickening member, the upper sheet 4, the upper adhesive layer 43, the upper electrode 41, the upper edge 431, and the upper gap 203, It corresponds to an example of the second sheet, the second adhesive layer, the second electrode, the second edge, and the second gap of the present invention, respectively. A lower thickening member may be provided on the lower main surface 21 of the spacer 2.

  Further, as shown in FIG. 5, thickening members may be provided on both the main surface 32 of the lower sheet 3 and the main surface 42 of the upper sheet 4. In this case, the shape and arrangement of the lower thickening member provided on the main surface 32 of the lower sheet 3 in plan view are the same as the shape and arrangement of the upper thickening member provided on the main surface 42 of the upper sheet 4 in plan view. May be different from each other. In this case, the upper sheet 4, the upper adhesive layer 43, the upper electrode 41, the upper edge 431, the upper gap 203, and the upper thickening member 45 are the first sheet, the first adhesive layer, the first thickness of the present invention. It corresponds to an example of the electrode, the first edge, the first gap, and the first thickening member, respectively, the lower sheet 3, the lower adhesive layer 33, the lower electrode 31, the lower edge 331, the lower gap 202, and The lower thickening member 35 corresponds to an example of the second sheet, the second adhesive layer, the second electrode, the second edge, the second gap, and the second thickening member of the present invention. .

  In the present embodiment, as shown in FIG. 1, the rubber dome 5 is attached to the upper main surface 421 of the upper seat 4. The rubber dome 5 is provided to return the key top to its original position when a pressing force is transmitted via a key top (not shown) provided in a state that allows the rubber dome 5 to move up and down. It is an elastic member made of a rubber material or the like. The rubber dome 5 includes a substantially cup-shaped main body portion 51 and an attachment portion 52 that spreads outward from the edge of the main body portion 51. In the present embodiment, the rubber dome 5 is directly attached to the upper main surface 421 of the upper seat 4, but is not particularly limited thereto. For example, a rubber dome support member (not shown) made of PET or the like may be provided on the upper main surface 421 of the upper sheet 4 and the rubber dome 5 may be attached to the upper sheet 4 via the cover member.

  A protrusion 511 formed to protrude downward in FIG. 1 is provided at the center of the inner surface of the main body 51. The attachment portion 52 is formed on the entire circumference of the main body portion 51, and the lower surface 523 is in close contact with the upper main surface 421 of the upper sheet 4. The outer edge shapes of the main body 51 and the attachment 52 are concentric with each other in plan view. In the present embodiment, the center of the outer edge shape of the main body 51 and the mounting portion 52 of the rubber dome 5 substantially coincides with the center C of the opening 20 of the spacer 2. The shape of the rubber dome 5 is not particularly limited to the above.

  In the present embodiment, as shown in FIG. 1, the shape and arrangement of the inner edge portion 521 in the mounting portion 52 of the rubber dome 5 in a plan view are substantially the same as the shape and arrangement of the opening 20 of the spacer 2. The lower edge 331 of the adhesive layer 33 and the upper edge 431 of the upper adhesive layer 43 are located on the center C side of the opening 20. On the other hand, the outer edge portion 522 of the mounting portion 52 of the rubber dome 5 is located outside the lower edge portion 331 of the lower adhesive layer 33 and the upper edge portion 431 of the upper adhesive layer 43 (on the side away from the center C of the opening 20). doing.

  Therefore, in the present embodiment, the lower gap 202 is formed at the overlapping portion of the spacer 2 and the lower sheet 3 in the region E occupied by the lower surface 523 of the rubber dome 5 in plan view. Similarly, the upper gap 203 is formed in an overlapping portion between the spacer 2 and the lower sheet 3 in a region E occupied by the lower surface 523 of the rubber dome 5 in plan view.

  When an input is made to the membrane switch 1, a pressing force applied from above in FIG. 1 is transmitted to the top portion of the main body 51 of the rubber dome 5 via a key top (not shown). Next, the lower surface 523 of the mounting portion 52 of the rubber dome 5 presses the upper sheet 4 by the pressing force, and the lower electrode 31 and the upper electrode 41 approach each other by the pressing. And the top part of the main-body part 51 deform | transforms so that it may dent toward the downward direction in FIG. 1, and the upper sheet | seat 4 is the lower sheet | seat 3 in the state which the front-end | tip of the processus | protrusion 511 contacted the upper main surface 421 of the upper sheet | seat 4. Is pressed, the lower electrode 31 and the upper electrode 41 come into contact with each other to conduct electricity, and input is performed.

  Next, the operation of the membrane switch 1 in this embodiment will be described.

  When the membrane switch is used for a keyboard of a notebook personal computer, if the notebook personal computer is carried in a closed state, the casing is slightly deformed by an external force applied to the notebook personal computer casing. Then, due to this deformation, the keyboard is pressed (ON state), and may be turned on unexpectedly. Further, when the keyboard is kept pressed (ON state), the electrode of the membrane switch may be damaged by the spark generated between the electrodes. Such a phenomenon is particularly likely to occur due to the thinning of the spacer of the membrane switch accompanying the thinning of the notebook personal computer.

  On the other hand, in the membrane switch 1 of the present embodiment, the inner edge 521 of the lower surface 523 of the rubber dome 5 in plan view is more than the upper edge 431 of the upper adhesive layer 43 positioned around the opening 20 of the spacer 2. It is located on the center C side of the opening 20. Further, in an area occupied by the lower surface 523 in plan view, an upper gap 203 is provided in an overlapping portion between the spacer 2 and the lower sheet 3, and an upper thickening member 45 is provided in the upper gap 203. .

  Therefore, when the membrane switch 1 is used as a keyboard of a notebook computer, if an external force applied to the casing of the notebook computer is first transmitted to the lower surface 523 of the mounting portion 52 of the rubber dome 5, the upper sheet 4 Is slightly curved toward the lower sheet 3. At this time, since the upper thickening member 45 is sandwiched between the upper sheet 4 and the spacer 2, the degree of bending of the upper sheet 4 due to external force is reduced.

  Thereby, it is possible to suppress the membrane switch 1 from being unexpectedly turned on due to the electrodes 31 and 41 coming into contact with each other by an external force transmitted from the rubber dome 5 and to prevent damage to the electrodes 31 and 41. This effect is further improved when the lower thickening member 35 is provided on the main surface 32 of the lower sheet 3 and the upper thickening member 45 is provided on the main surface 42 of the upper sheet 4 as shown in FIG. In the present embodiment, the end 451 on the opening 20 side of the spacer 2 in the upper thickening member 45 extends to the inside of the opening 20, so that the upper sheet 4 is based on the opening end of the spacer 2. Bending is suppressed. Thereby, since the degree of curvature of the upper sheet 4 when an external force is applied can be reduced, the above effect can be further improved.

  In the present embodiment, a plurality of upper thickening members 45 are provided on the main surface 42 of the upper sheet 4 so as to be separated from each other. For this reason, it is possible to more effectively suppress the membrane switch 1 from being unexpectedly turned on and damage to the electrodes 31 and 41.

  In the present embodiment, the upper thickening member 45 is formed independently of the upper electrode 41. For this reason, the upper thickening member 45 can be formed from a material different from silver or the like constituting the upper electrode 41, and the cost of the membrane switch 1 can be reduced.

  In the present embodiment, as described above, the gaps 202 and 203 are provided between the spacer 2 and the lower sheet 3 and between the spacer 2 and the upper sheet 4. Thereby, at the time of the input of the membrane switch 1, it is possible to prevent the switching performance from being deteriorated due to the lower adhesive layer 33 or the upper adhesive layer 43 protruding near the electrodes 31 and 41.

  The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, as shown in FIG. 6, the outer edge portion 522 of the attachment portion 52 of the rubber dome 5 </ b> B may be located closer to the center C side of the opening 20 than the upper edge portion 431 of the upper adhesive layer 43. That is, the position of the outer edge portion 522 of the mounting portion 52 of the rubber dome 5B may correspond to the position of the gap 203. In this case, since the external force transmitted to the rubber dome 5B is easily transmitted to the upper thickening member 45, the membrane switch 1 is more effectively prevented from being turned on unexpectedly and the electrodes 31 and 41 are prevented from being damaged. can do. 6, the outer edge 522 of the mounting portion 52 of the rubber dome 5 </ b> B is not affected by any of the lower edge 331 of the lower adhesive layer 33 and the upper edge 431 of the upper adhesive layer 43. In the case where it is located closer to the center C side of the opening 20 than the portion, it is further improved.

DESCRIPTION OF SYMBOLS 1 ... Membrane switch 2 ... Spacer 20 ... Opening part 201 ... Peripheral part 202 ... Lower gap 203 ... Upper gap 21 ... Lower main surface 22 ... Upper main surface DESCRIPTION OF SYMBOLS 3 ... Lower sheet 31 ... Lower electrode 32 ... Main surface 33 ... Lower adhesion layer 331 ... Lower edge 35 ... Lower thickening member 4 ... Upper sheet 41 ... Upper electrode 42 ... main surface 43 ... upper adhesive layer 431 ... upper edge 45, 45B, 45C ... upper thickening member 5, 5B ... rubber dome 51 ... main body 52 .... Mounting part 521 ... Inner edge 522 ... Outer edge 523 ... Lower surface

Claims (8)

A spacer having an opening;
A first sheet provided corresponding to the opening, and provided on one main surface of the spacer via a first adhesive layer;
A second sheet provided on the other principal surface of the spacer via a second adhesive layer, having a second electrode provided to face the first electrode via the opening; With
By the pressing force applied to the first sheet or the second sheet through a rubber dome having a mounting portion corresponding to the peripheral edge of the opening, the first electrode and the second electrode are connected to each other. In membrane switches that are brought into contact with each other,
The inner edge portion of the attachment portion in plan view is located closer to the center side of the opening portion than the first edge portion of the first adhesive layer located around the opening portion,
In a region occupied by the attachment portion in plan view, a first gap formed by the first edge portion being located outside the opening portion at an overlapping portion between the spacer and the first sheet. Is provided,
A membrane switch, wherein a first thickening member is provided in the first gap. The membrane switch according to claim 1,
The membrane switch according to claim 1, wherein the first thickening member is provided on the first sheet. The membrane switch according to claim 2, wherein
The membrane switch according to claim 1, wherein an end of the first thickening member on the center side of the opening extends to the inside of the opening. The membrane switch according to claim 2 or 3,
The membrane switch according to claim 1, wherein the first thickening member is formed integrally with the first electrode. The membrane switch according to claims 1 to 3,
The membrane switch according to claim 1, wherein the first thickening member is formed independently of the first electrode. The membrane switch according to claim 5, wherein
A membrane switch characterized in that a plurality of the first thickening members arranged apart from each other are provided on the first sheet. The membrane switch according to any one of claims 1 to 6,
The membrane switch according to claim 1, wherein an outer edge portion of the attachment portion in plan view is located closer to a center side of the opening portion than the first edge portion. The membrane switch according to any one of claims 1 to 7,
The inner edge portion of the attachment portion in plan view is located closer to the center side of the opening portion than the second edge portion of the second adhesive layer located around the opening portion.
In a region occupied by the mounting portion in plan view, a second gap formed by the second edge portion being located outside the opening portion at an overlapping portion between the spacer and the second sheet. Is provided,
A membrane switch, wherein a second thickening member is provided in the second gap.

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