JP2016091797A - Membrane switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a membrane switch that can reduce a gap between a feeling of pressing a rubber dome and a point where an electrically ON state is entered.SOLUTION: A membrane switch 1 comprises a lower sheet 3 which has a lower electrode 31 provided corresponding to an opening part 20 of a spacer 2, and is provided on one main surface 21 of a spacer with a lower adhesive layer 33 interposed, and an upper sheet 4 which has an upper electrode 41 provided opposite the lower electrode with the opening part interposed, and is provided on the other main surface 22 of the spacer with an upper adhesive layer 43 interposed, and turns on by bringing the lower electrode and upper electrode into contact with each other with press force applied to the upper sheet through a rubber dome 5 having a fitting part 52 corresponding to a peripheral edge part of the opening part, an upper edge part 522 on a reverse surface of the rubber dome in plan view being positioned between the opening part of the spacer and a lower edge part 331 of the lower adhesive layer positioned at a periphery of the opening part.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 keyboard or the like that is configured by attaching a rubber dome that is elastically deformed by a pressing force to the upper part of the membrane switch as described above, the amount of pushing required until the electrodes come into contact after the rubber dome is pushed and deformed Therefore, there is a problem that there is a large gap between the feeling of pressing the rubber dome and the point where it is electrically turned on.

  The problem to be solved by the present invention is to provide a membrane switch that can reduce the distance between the sense of pressing the rubber dome and the point where it is electrically turned 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 outer edge portion of the attachment portion in a plan view has the opening portion and the first portion located around the opening portion. Located between the first edge of the adhesive layer of And wherein the Rukoto.

  [2] In the above invention, the outer edge portion may be located between the opening and the second edge of the second adhesive layer located around the opening.

  [3] In the above invention, a protrusion may be provided around the first electrode in the first sheet and located inside the opening in plan view.

  [4] In the above invention, the height of the protrusion may be greater than the height of the first electrode.

  According to the present invention, the outer edge portion of the rubber dome mounting portion in plan view includes the opening portion of the spacer, the first edge portion of the first adhesive layer positioned around the opening portion, and the periphery of the opening portion. And at least one of the second edges of the second pressure-sensitive adhesive layer. Thereby, when the rubber dome is pushed in, the first electrode and the second electrode can be brought close to each other before the rubber dome is deformed. For this reason, the distance between the feeling of pressing the rubber dome and the point at which it is electrically turned on can be reduced.

FIG. 1 is a cross-sectional view showing a membrane switch in a first embodiment of the present invention. FIG. 2 is a sectional view showing a modification of the membrane switch in the first embodiment of the present invention. FIG. 3 is a graph for explaining the action of the membrane switch in the first embodiment of the present invention. FIG. 4 is a cross-sectional view showing a membrane switch according to a second embodiment of the present invention.

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

<< First Embodiment >>
FIG. 1 is a cross-sectional view showing a membrane switch in the first embodiment, and FIG. 2 is a cross-sectional view showing a modification of the membrane switch in the first embodiment.

  The membrane switch 1 in the present embodiment is an input switch used for a keyboard of, for example, a notebook personal computer, and as shown in FIG. 1, a spacer 2, a lower sheet (first sheet) 3, an upper sheet (first sheet) 2 sheet) 4. 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 may be any shape that surrounds the lower electrode 31 and the upper electrode 41 in plan view, and is not particularly limited. 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 lower main surface 21 of the spacer 2 in the present embodiment corresponds to an example of one main surface of the present invention, and the upper main surface 22 corresponds to an example of the other main surface of the present invention.

  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 gap 202 is formed between the spacer 2 and the lower sheet 3 at the peripheral edge 201 of the opening 20.

  The outer shape of the lower electrode 31 has a circular shape smaller than the opening 20 of the spacer 2 in plan view, and is provided at a position corresponding to the opening 20 of the spacer 2 in the lower sheet 3. That is, in the plan view, the center of the lower electrode 31 and the center C of the opening 20 of the spacer 2 substantially coincide with each other. Note that 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 It is located around the opening 20 in plan view.

  Thus, a gap 203 is formed between the spacer 2 and the upper sheet 4 at the peripheral edge 201 of the opening 20. In the present embodiment, the lower edge 331 of the lower adhesive layer 33 and the upper edge 431 of the upper adhesive layer 43 have substantially the same shape in plan view.

  Although not particularly illustrated, the lower sheet 3 is provided with a lead wiring connected to the lower electrode 31, and the upper sheet 4 is provided with a lead wiring connected to the upper electrode 41. An electrical connection state between the lower electrode 31 and the upper electrode 41 is detected through these lead wires.

  The outer shape of the upper electrode 41 has the same circular shape as that of the lower electrode 31 and is provided at a position corresponding to the opening 20 of the spacer 2. In other words, the center of the upper electrode 41 and the center C of the opening 20 of the spacer 2 substantially coincide with each other in plan view. 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.

  In the present embodiment, the thickness of the lower adhesive layer 33 and the thickness of the upper adhesive layer 43 are substantially equal to each other, but are not particularly limited thereto. For example, as shown in FIG. 2, the thickness D2 of the upper adhesive layer 43 may be larger than the thickness D1 of the lower adhesive layer 33 (D1 <D2). In the present embodiment, the shape and arrangement of the lower edge portion 331 of the lower adhesive layer 33 in plan view are substantially the same as the shape and arrangement of the upper edge portion 431 of the upper adhesive layer 43, but they are different from each other. It may be.

  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 outer edge shape of the rubber dome 5 is not particularly limited to the above.

  In the present embodiment, as shown in FIG. 1, the position of the inner edge portion 521 of the attachment portion 52 of the rubber dome 5 substantially coincides with the position of the edge portion 200 of the opening 20 of the spacer 2. The position of the inner edge portion 521 of the attachment portion 52 of the rubber dome 5 may be located in the opening 20 of the spacer 2.

  On the other hand, the position of the outer edge portion 522 of the mounting portion 52 of the rubber dome 5 is located slightly on the center C side of the opening 20 from the position of the lower edge portion 331 of the lower adhesive layer 33 and the upper edge portion 431 of the upper adhesive layer 43. doing. It is preferable that the distance between the outer edge 522 and the lower edge 331 and the distance between the outer edge 522 and the upper edge 431 are longer. That is, as shown in FIG. 2, the position of the outer edge portion 522 is preferably located closer to the center C side of the opening portion 20 than the edge portions 331 and 431.

  Next, the operation of the membrane switch 1 in this embodiment will be described. FIG. 3 is a graph for explaining the operation of the membrane switch 1 in the present embodiment.

  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 front-end | tip of the processus | protrusion 511 contacts the upper side main surface 421 of the upper sheet | seat 4. FIG. Next, when the upper sheet 4 is pressed toward the lower sheet 3 through the rubber sheet 5 in this state, the lower electrode 31 and the upper electrode 41 come into contact with each other, and input is performed.

  In the above series of operations, the relationship between the pushing amount of the rubber dome 5 and the load applied at the time of pushing at the time of input is as shown in the graph of FIG. That is, at the stage before the rubber dome 5 starts to deform (step 1 in FIG. 3, S1 in the graph), the load at the time of pushing increases as the pushing amount of the rubber dome 5 increases. And if the load at the time of pushing exceeds a peak, the rubber dome 5 will begin to deform | transform so that it may dent.

  Next, when the protrusion 511 of the main body 51 of the rubber dome 5 comes into contact with the upper sheet 4 (step 2 in FIG. 3, S2 in the graph), the load during pushing becomes a minimum value, and the input person A sensation of deformation of the dome 5 (feeling of pushing the rubber dome) is obtained. Subsequently, when the rubber dome 5 is further pushed while the protrusion 511 of the main body 51 of the rubber dome 5 is in contact with the upper sheet 4, the load at the time of pushing again increases and the lower electrode 31 and the upper electrode 41 are increased. And the membrane switch 1 is turned on (step 3 in FIG. 3, S3 in the graph).

  Here, the outer edge 522 of the mounting portion 52 of the rubber dome 5 is between the opening 20 of the spacer 5 and at least one of the lower edge 331 of the lower adhesive layer 33 and the upper edge 431 of the upper adhesive layer 43. 3 (graph A in FIG. 3), the outer edge 522 of the mounting portion 52 is located outside the edges 331 and 431 (graph B in FIG. 3). In the stage up to step 2, the pressing force transmitted through the mounting portion 52 of the rubber dome 5 is easily transmitted toward the gaps 202 and 203 (see FIG. 1).

  Accordingly, the gaps 202 and 203 are compressed by the pressing force, so that the distance between the lower electrode 31 and the upper electrode 41 is reduced in the step 2 of FIG. For this reason, it is possible to reduce the distance (the difference in pushing amount between Step 2 and Step 3 in FIG. 3) between the feeling of pressing the rubber dome 5 and the point where the membrane switch 1 is electrically turned on. Yes (W1 <W2). As shown in FIG. 2, this effect is further improved as the distance between the outer edge 522 of the rubber dome 5 and the edges 331 and 431 is longer. However, when the distance between the outer edge portion 522 and the edge portions 331 and 431 of the rubber dome 5 is too long, the rubber dome 5 or the weight of a key top (not shown) attached above the rubber dome 5 is used. The possibility of causing an erroneous input due to the contact between the lower electrode 31 and the upper electrode 41 is increased. For this reason, the distance between the outer edge portion 522 of the rubber dome 5 and the edge portions 331 and 431 is not more than three times the distance from the edge portion 200 of the opening 20 of the spacer 2 to the outer edge portion 522 of the rubber dome 5. It is preferable.

  In the present embodiment, the outer edge portion 522 of the rubber dome 5 is located between the lower edge portion 331 of the lower adhesive layer 33 and the edge portion 200 of the opening 20 of the spacer 2, and It is located between the upper edge 431 and the edge portion 200 of the opening 20 of the spacer 2. For this reason, said effect can be improved further. Even when the position of the inner edge portion 521 of the attachment portion 52 of the rubber dome 5 is located in the opening portion 20 of the spacer 2, the above effect can be further improved.

  As shown in FIG. 2, when the thickness D2 of the upper adhesive layer 34 is made larger than the thickness D1 of the lower adhesive layer 33 while keeping the distance between the lower sheet 3 and the upper sheet 4 constant. (D1 <D2), the gap 203 becomes larger than the gap 202, so that the lower electrode 31 becomes closer to the upper electrode 41. Thereby, in the step 2 of FIG. 3, the distance between the lower electrode 31 and the upper electrode 41 can be further reduced, so that the above effect can be further achieved without increasing the thickness of the entire membrane switch 1. This can be further improved.

  The lower sheet 3, the lower adhesive layer 33, the lower electrode 31, and the lower edge 331 in this embodiment are the first sheet, the first adhesive layer, the first electrode, and the first edge of the present invention. Each corresponds to one example, and the upper sheet 4, the upper adhesive layer 43, the upper electrode 41, and the upper edge 431 in the present embodiment are the second sheet, the second adhesive layer, the second electrode, and the present invention. Each corresponds to an example of the second edge.

  In addition, you may apply this invention as a structure which mutually replaced the lower sheet | seat 3 etc. and the upper sheet | seat 4 grade | etc.,. That is, the lower sheet 3, the lower adhesive layer 33, the lower electrode 31, and the lower edge 331 in the present embodiment are the second sheet, the second adhesive layer, the second electrode, and the second edge of the present invention. The upper sheet 4, the upper adhesive layer 43, the upper electrode 41, and the upper edge portion 431 in the present embodiment are respectively the first sheet, the first adhesive layer, and the first electrode of the present invention. The present invention may be applied as configurations corresponding to examples of the first edge and the first edge, respectively.

<< Second Embodiment >>
FIG. 4 is a cross-sectional view showing a membrane switch in the second embodiment of the present invention. Since the membrane switch in the second embodiment is the same as the first embodiment described above except that the lower sheet is provided with a protrusion, only the parts different from the first embodiment will be described. The same reference numerals as those in the embodiment are attached and the description thereof is omitted.

  In the membrane switch 1 </ b> B in the present embodiment, as shown in FIG. 4, protrusions 30 are provided around the lower electrode 31 in the lower sheet 3. The protrusion 30 is disposed so as to surround substantially the entire circumference of the lower electrode 31 in a plan view, and is made of substantially the same material as the lower electrode 31. In addition, the material which comprises the projection part 30 is not specifically limited. For example, you may comprise the said projection part 30 from insulating materials, such as a resin material.

  Further, the shape and arrangement of the protrusion 30 are not particularly limited. For example, the protrusions 30 may be integrally formed so as to surround the periphery of the lower electrode 31, and a plurality of protrusions 30 formed independently of each other are arranged around the lower electrode 31 at predetermined intervals. May be. Moreover, in this embodiment, although the projection part 30 is provided only in the lower sheet | seat 3, it is not limited to this in particular. For example, although not particularly illustrated, a similar protrusion may be provided around the upper electrode 41 in the upper sheet 4, and protrudes both around the lower electrode 31 in the lower sheet 3 and around the upper electrode 41 in the upper sheet. A part may be provided.

  Although the height (thickness) of the protrusion 30 is not particularly limited, it is preferable that the height L1 of the protrusion 30 is larger than the height L2 of the lower electrode 31 as shown in FIG. 4 (L1> L2). In the case where a protrusion is provided around the upper electrode 41 in the upper sheet 4, the height of the protrusion is preferably larger than the height of the upper electrode 41.

  The protrusion 30 is located inside the opening 20 of the spacer 2 in plan view. For this reason, in this embodiment, all the protrusions 30 face the main surface 42 of the upper sheet 4.

  Also in the membrane switch 1B in the present embodiment, the outer edge portion 522 of the rubber dome 5 is located closer to the center C side of the opening 20 of the spacer 2 than the lower edge portion 331 of the lower adhesive layer 33, and the upper adhesive layer. 43 is located closer to the center C side than the upper edge portion 431. For this reason, the same effect as the membrane switch 1 demonstrated in 1st Embodiment can be show | played.

  In the present embodiment, the protrusion 30 is provided around the lower electrode 31 in the lower sheet 3. For this reason, it is possible to prevent erroneous input due to contact between the lower electrode 31 and the upper electrode 41 due to the weight of the rubber dome 5 or a key top (not shown) attached above the rubber dome. In this embodiment, since the height L1 of the protrusion 30 is larger than the height L2 of the lower electrode 31, this effect can be further improved. In addition, when the protrusions are provided on both the lower sheet 3 and the upper sheet 4, this effect can be further improved.

  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.

DESCRIPTION OF SYMBOLS 1, 1B ... Membrane switch 2 ... Spacer 20 ... Opening part 200 ... Edge part 201 ... Peripheral part 202, 203 ... Gap 21 ... Lower main surface 22 ... Upper main surface 3 ... Lower sheet 30 ... Projection 31 ... Lower electrode 33 ... Lower adhesive layer 331 ... Lower edge 4 ... Upper sheet 41 ... Upper electrode 43 ... Upper adhesive layer 431: Upper edge 5, 5B ... Rubber dome 51 ... Main body 52 ... Mounting portion 521 ... Inner edge 522 ... Outer edge 523 ... Lower surface

Claims (4)

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,
An outer edge portion of the mounting portion in plan view is located between the opening and the first edge of the first adhesive layer located around the opening. Membrane switch. The membrane switch according to claim 1,
The membrane switch, wherein the outer edge is located between the opening and the second edge of the second adhesive layer located around the opening. The membrane switch according to claim 1 or 2,
The membrane switch according to claim 1, wherein a projection is provided around the first electrode in the first sheet and is located inside the opening in a plan view. The membrane switch according to any one of claims 1 to 3,
The membrane switch according to claim 1, wherein the height of the protrusion is greater than the height of the first electrode.

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