JP5249650B2 - Membrane switch and manufacturing method thereof - Google Patents

Description

  The present invention relates to a membrane switch, and more particularly to a thin membrane switch that is used in an electronic device and has a clear click feeling.

  2. Description of the Related Art Conventionally, membrane switches have been widely used all over the world, ranging from key switches for PC peripheral devices and mobile phones to operation panels for consumer devices such as microwave ovens and washing machines. However, in recent years, demands for miniaturization, weight reduction, thickness reduction, and price reduction have increased.

  Referring to FIGS. 6 and 8, the conventional membrane switch 101 is a switch element composed of a pair of contact electrodes 109 and 111 disposed on two substrates 105 and 107 facing each other with a gap between them with a spacer 103 interposed therebetween. The top sheet 113 is a switch having a double-sided adhesive material 115 attached thereto. The two substrates 105 and 107 are bonded to both surfaces of the spacer 103 with a double-sided adhesive material 117.

  Further, the top sheet 113 includes a plurality of embossed portions 119 (pressing portions) embossed in a spherical shape toward the opposite side of the switch element at a position corresponding to the switch element, A protrusion 121 protruding toward the switch element is provided around the periphery. The projecting portion 121 is formed at a plurality of locations around the embossed portion 119, for example, at four locations with an interval of 90 °, or at eight locations, and is devised so as to be reversed while generating a click feeling. A design printing layer 123 is formed on the surface of the top sheet 113 on the embossing side.

  As shown in FIG. 8, the manufacturing method of the membrane switch 101 includes a flexible substrate 105 having contact electrodes 109 and 111 formed by printing silver paste on the surface of, for example, PET as an insulating resin by screen printing. 107 is formed. A double-sided adhesive material 117 is attached to the flexible substrates 105 and 107 to form first and second flexible substrates 105 and 107 with an adhesive material. Further, the switch element is formed by attaching the spacer 103 between the first and second flexible substrates 105 and 107 so that the contact electrodes 109 and 111 face each other.

  On the other hand, as shown in FIG. 7, the surface sheet 113 is formed by providing a design printing layer 123 by screen printing on, for example, PET as an insulating material. The embossed portion 119 is formed by embossing the surface sheet 113 from the surface side of the design print layer 123 toward the PET side using a mold. At the same time, a protruding portion 121 is formed around the embossed portion 119 from the PET side toward the design printing layer 123 side. The membrane switch 101 is formed by adhering the switch element and the embossed portion 119 of the top sheet 113 with the double-sided adhesive material 115 so that the positions of the embossed portions 119 of the top sheet 113 are matched.

Japanese Patent Application Laid-Open No. H10-228707 discloses a conventional membrane switch 101 described above.
JP-A-2005-19281

  By the way, in the conventional membrane switch 101, in order to adjust the click feeling, there is a problem that it takes time to design the projecting portion 121 projecting toward the switch element on the surface sheet 113 and the embossed shape. . At the same time, as the embossed shape of the topsheet 113 becomes complicated, there is a problem that the number of mold design steps increases.

  Further, the conventional membrane switch 101 has a click feeling due to the protruding portion 121 and the embossed portion 119 on the top sheet 113. However, when the top sheet 113 is deteriorated by repeated use, the click feeling is deteriorated. was there.

  An object of the present invention is to provide a switch having a long life by increasing the degree of freedom in designing a switch.

In order to solve the above-described problems, the membrane switch of the present invention includes a substrate having a fixed contact portion including a central contact and an outer peripheral contact disposed around the central contact on the surface, and the outer peripheral contact of the substrate. A switch dome made of a stainless steel or copper-based metal that is flexible and has a crest-shaped movable contact portion that has an outer peripheral edge that abuts against the central contact, and a resin sheet, An adhesive layer provided on one surface of the resin sheet, and is attached to the substrate to hold the switch dome at a predetermined position on the substrate. a convex side entire surface pasted dome pressing member, embossed portion is positioned outwardly of the dome for the switch, and provided with a printed design layer on the front surface of the embossed side And the surface sheet is provided to press the switch dome inside the printed design layer of the embossed portion includes a protruding portion formed by printing a resin, and for the the projecting portion of the printed design layer switch The dome pressing member and the design printing layer are integrated with an adhesive material at a portion other than the embossed portion so that the position of the movable contact portion of the dome is matched.

In the membrane switch of the present invention, in the membrane switch, the adhesive material is preferably a double-sided adhesive material.
The membrane switch manufacturing method of the present invention forms a substrate having a fixed contact portion comprising a central contact and an outer peripheral contact disposed around the central contact on the surface, and processes a plate made of stainless steel or copper-based metal. And forming a flexible and saddle-shaped switch dome having an outer peripheral edge abutting against the outer peripheral contact of the substrate and a movable contact portion at the top of the head facing the central contact. An adhesive layer is provided on one surface of the sheet to form a dome pressing member, and the dome pressing member is attached to the entire convex surface of the switch dome, and the switch dome is disposed at a predetermined position on the substrate. in order to suppress in order to paste the dome pressing member on the substrate, it is performed with the embossed portion to the resin sheet, a design printed layer formed by printing on the front surface of the d Nbosu working side, A projection for pressing the dome switch inside the serial printed design layer to form a surface sheet by printing a resin, placing the topsheet outwardly of the dome for the switch, the printed design layer The dome pressing member and the design print layer are integrated with an adhesive material at a portion other than the embossed portion so that the protrusions of the switch and the movable contact portion of the switch dome are aligned.

  As can be understood from the means for solving the problems as described above, according to the present invention, the surface sheet provided with the embossed portion is only provided with the design printing layer, and therefore, the degree of freedom in design and structural design. High membrane switch can be obtained. In addition, since the click feeling is obtained by a switch dome provided separately, a good click feeling can be maintained even after the surface sheet is deteriorated, and a long-life membrane switch can be obtained. In addition, the thickness can be further reduced.

  Embodiments of the present invention will be described below with reference to the drawings.

  Referring to FIGS. 1 to 4, a membrane switch 1 according to this embodiment is provided for a plurality of switches on a printed wiring board 3 such as a PCB (Printed Circuit Board) or FPC (Flexible Printed Circuit) as a board. A dome 5 (metal dome or metal click spring) is incorporated. A switch element is formed by a fixed contact portion (described later in detail) provided on the printed wiring board 3 and each switch dome 5.

  Further, the top sheet 7 made of an insulating resin having a plurality of embossed portions 9 (pressing portions) embossed is positioned above the corresponding switch dome 5. It is an integrated structure that is affixed to the printed wiring board 3 with a double-sided adhesive material 11.

  In this embodiment, a plurality of switch elements are provided as shown in FIG. 4, but only one switch element can be applied. Therefore, the membrane switch 1 is provided with one or a plurality of switch elements in a sheet form as a whole as shown in FIG. 4 with the printed wiring board 3 and the surface sheet 7 attached thereto. It is a form.

  The switch dome 5 is obtained by processing a plate material of, for example, stainless steel or copper-based metal as a conductive material. Furthermore, it is of a saddle shape having flexibility that can be brought into and out of contact with the contact portion on the substrate 3. The switch dome 5 has a diameter of, for example, 4 mm and a height of, for example, 0.2 mm.

  Further, the printed wiring board 3 is provided with a central contact (center electrode) 15A made of a conductive material on the insulating sheet 13, and an outer peripheral contact (outer peripheral electrode) 15B is annularly provided around the central contact 15A. The central contact 15A and the outer peripheral contact 15B constitute a fixed contact portion 15 serving as an electrode pair. A circuit is formed on the printed wiring board 3 in a pattern.

  On the printed wiring board 3, the switch dome 5 described above is arranged in alignment with the center contact 15A and the outer peripheral contact 15B of the electrode pair. That is, the switch dome 5 has a movable contact portion 5A located on the concave side of the top of the switch dome 5 so that the conduction between the central contact 15A and the outer peripheral contact 15B is turned ON / OFF. The bowl-shaped outer periphery is mounted so as to be connected to the outer peripheral contact 15B.

  The above-mentioned switch dome 5 is positioned on the base plate 3 by a dome presser sheet 17 as a dome presser member 17 as a dome presser member made of a resin sheet such as an insulating rubber sheet. .

  The dome presser sheet 17 includes, for example, a sheet material based on a resin sheet such as PET (polyethylene terephthalate), and an adhesive layer made of, for example, an acrylic or silicon adhesive material applied to one surface of the sheet material. The pressure-sensitive adhesive layer that is a single-sided adhesive material configured to hold the switch dome 5 is the same as the adhesive that is directly attached to the surface of the substrate 3.

  The switch dome 5 is disposed so as to cover the center contact 15A substantially in the center, that is, the center contact 15A is located on the center direction side of the bowl-shaped concave surface. In other words, when the top of the switch dome 5 is pressed downward, the vicinity of the top is reversed so that it is depressed so that the movable contact portion 5A contacts the central contact 15A and is conductive. Yes.

  The top sheet 7 is provided with a plurality of embossed portions 9 embossed in a spherical shape toward the opposite side of the switch dome 5 at a position corresponding to the switch dome 5. Further, a design printing layer 19 is provided on the surface of the top sheet 7 on the embossing side, and a protruding portion 21 is printed and formed almost at the center of the embossed portion 9.

  As shown in FIG. 3, the manufacturing method of the membrane switch 1 according to this embodiment is such that a silver paste is printed on the surface of, for example, PET (polyethylene terephthalate) as the insulating sheet 13 by screen printing, and the central contact 15A. For example, the flexible substrate 3 is formed as a printed wiring board having a fixed contact portion 15 (contact electrode) composed of the outer peripheral contact 15B. The switch dome 5 is affixed to the dome presser sheet 17 that is a single-sided adhesive material, and the dome presser sheet 17 is affixed to the insulating sheet 13 of the flexible substrate 3 to form a switch element having the switch dome 5.

  On the other hand, as shown in FIG. 2, the surface sheet 7 is formed by printing the design printing layer 19 and the protruding portion 21 on the PET, which is a sheet-like insulating resin, by screen printing. The embossed portion 9 is formed by embossing the surface sheet 7 in a circular arc shape around the projection 21 from the surface side of the design printing layer 19 toward the PET side using a mold.

  The surface sheet 7 is affixed to the dome presser sheet 17 on the flexible substrate 3 with a double-sided adhesive material 11 such as a double-sided adhesive tape so that the positions of the switch dome 5 and the embossed portion 9 of the surface sheet 7 are aligned. Thus, the membrane switch 1 is formed.

  With the configuration described above, the membrane switch 1 according to this embodiment is configured so that when the embossed portion 9 formed on the topsheet 7 is pushed in by a human finger or the like, as shown in FIG. The provided projecting portion 21 pushes down the movable contact portion 5 </ b> A at the top of the dome 5 for switch from above the dome presser sheet 17.

  Then, the movable contact portion 5A at the top of the dome 5 for the switch is displaced and deformed, and is pushed into the switch dome 5 so as to be recessed. Thereby, the movable contact portion 5A of the switch dome 5 is in contact with the central contact 15A, and the central contact 15A and the outer peripheral contact 15B, which are paired electrodes, are electrically connected to each other via the switch dome 5. The membrane switch 1 is turned on.

  At this time, the switch dome 5 is inverted and recessed near the top of the switch dome 5, so that a click feeling can be obtained during this deformation. Further, when the finger or the like is removed from the embossed portion 9 of the topsheet 7, the switch dome 5 returns to the original position of the initial shape by its own elastic force, so the embossed portion 9 of the topsheet 7 also returns to the original position, The central contact 15A and the outer peripheral contact 15B, which are electrodes forming a pair, are electrically disconnected, and the membrane switch 1 is turned off.

  Next, in order to examine the effect of the membrane switch 1 of the above embodiment, an example based on the configuration of this embodiment is created, and the conventional membrane of FIG. The switch 101 was created as a comparative example.

  In each of Examples and Comparative Examples, membrane switches 1 and 101 were manufactured by using the materials shown below and the manufacturing methods of Examples and Comparative Examples.

  As the material used, the flexible substrates 3, 105, 107 are made of PET film [manufactured by Teijin DuPont Films Co., Ltd., model number: HSL] and have a thickness of 100 μm. A conductive ink mainly composed of silver that forms an electric circuit including contact electrodes on the substrates 3, 105, and 107 is a silver paste [model number: DX-351H-30 manufactured by Toyobo Co., Ltd.].

  The surface sheets 7 and 113 are made of PET film [manufactured by Teijin DuPont Films Co., Ltd., model number: HSL] and have a thickness of 100 μm. The design printing layers 19 and 123 were subjected to design printing with design printing ink [model number; PAL mat manufactured by Seiko Advance Co., Ltd.].

  The protrusion part 21 of the Example was formed by printing with a UV curable resin ink [manufactured by Toyo Ink Mfg. Co., Ltd., model number: SS Braille ink].

  As the double-sided pressure-sensitive adhesive materials 11, 115, 117, those of Tessa Tape Co., Ltd. (model number: 4983 manufactured by the company) were used.

  The material used for the switch dome 5 of the example was SUS [stainless steel, model number manufactured by Yamamoto Co., Ltd .; F3016S].

  The dome presser sheet 17 (single-sided adhesive material) of the example was made of a polyester film tape [Isawa Co., Ltd .; [5]].

  The spacer 103 of the comparative example uses a PET film [manufactured by Teijin DuPont Films, Inc., model number: HSL], and has a thickness of 25 μm.

  A keystroke endurance test was performed on the embossed portions 9 and 119 of the membrane switches 1 and 101 of the above examples and comparative examples. In the keystroke endurance test, silicon rubber (hardness 50, SR7 mm) was used as the keystroke element. The keystroke load is 7N and the number of keystrokes is 500,000. Note that the N number is N = 6.

As a result, the click rate after the keystroke endurance test is as shown in Table 1. The pusher used for the click rate was made of brass with a diameter of 2.0 mm and the tip was flat.

  As can be seen from Table 1, when the surface sheets 7 and 113 are deteriorated, it is 20.5% in the comparative example, and is reduced to about 2/3 compared to 30.3% before the keystroke durability test. On the other hand, in the example, it is 29.8%, which is not much lower than 32.7% before the key hit durability test. Therefore, it was confirmed that the click feeling could be sustained in the example.

  From the above, the membrane switch 1 according to this embodiment has a click feeling controlled by the arc-shaped switch dome 5, so that the embossed shape of the topsheet 7 is designed considering only the design printing layer 19. Is possible. As a result, the design is easy and the degree of freedom in design is increased.

  In addition, since no spacer is required between the flexible printed wiring board 3 and the top sheet 7, the thickness can be reduced as compared with the conventional structure.

  In addition, since the click feeling is obtained by the switch dome 5 provided separately, even if the surface sheet 7 is deteriorated by repeated use of the membrane switch 1, the switch dome 5 does not deteriorate the click feeling. Therefore, a switch structure with a long life can be obtained.

It is sectional drawing of the membrane switch of embodiment of this invention. It is sectional drawing of the surface sheet of FIG. It is sectional drawing by the side of the board | substrate of FIG. It is a whole perspective view of the membrane switch which shows a partial section. It is a state explanatory view showing the operation of FIG. It is sectional drawing of the conventional membrane switch. It is sectional drawing of the surface sheet of FIG. It is sectional drawing by the side of the board | substrate of FIG.

Explanation of symbols

1 Membrane switch 3 Printed wiring board (board)
5 Dome for switch 5A Movable contact part 7 Surface sheet 9 Embossed part 11 Double-sided adhesive 13 Insulating sheet 15 Fixed contact part 15A Center contact (center electrode)
15B Peripheral contact (peripheral electrode)
17 Dome presser sheet (dome presser member)
19 Design printing layer 21 Protrusion

Claims (3)

A substrate provided on the surface with a fixed contact portion comprising a central contact and an outer peripheral contact disposed around the central contact;
A flexible switch-shaped dome made of stainless steel or copper-based metal having an outer peripheral edge abutting against the outer peripheral contact of the substrate and having a movable contact portion at the top facing the central contact; ,
It consists of a resin sheet and an adhesive layer provided on one surface of the resin sheet, and is affixed on the substrate in order to hold the switch dome at a predetermined position on the substrate, A dome holding member affixed to the entire convex surface of the switch dome;
And the surface sheet embossed portion, and provided with a printed design layer on the front surface of the embossed side located outside of the dome for said switch,
A protrusion formed on the inside of the design printing layer of the embossed portion for pressing the switch dome, and printed with resin.
The dome pressing member and the design print layer are integrated with an adhesive material at a portion other than the embossed portion so that the protrusions of the design print layer and the movable contact portion of the switch dome are aligned. Membrane switch characterized by that.   The membrane switch according to claim 1, wherein the adhesive material is a double-sided adhesive material. Forming a substrate with a fixed contact portion comprising a central contact and an outer peripheral contact disposed around the central contact on the surface;
A flexible and saddle-shaped plate having a peripheral contact with the outer peripheral contact of the substrate and a movable contact portion at the top facing the central contact while processing a plate made of stainless steel or copper-based metal Form a switch dome of shape,
An adhesive layer is provided on one surface of the resin sheet to form a dome presser member,
Affixing the dome presser member on the entire surface of the convex surface of the switch dome and affixing the dome presser member on the substrate to hold the switch dome at a predetermined position on the substrate,
The resin sheet is performed with an embossed portion, a design printed layer formed by printing on the front surface of the d Nbosu processing side, a protrusion for pressing the dome switch inside the printed design layer by printing a resin Forming a face sheet,
The dome presser member and the design print layer are arranged so that the surface sheet is disposed outside the switch dome, and the protrusions of the design print layer and the movable contact portions of the switch dome are aligned. A method for manufacturing a membrane switch, wherein a portion other than the embossed portion is integrated with an adhesive material.

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