JP2007220528A - Movable contact structure, and push-button switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a movable contact structure having an excellent click feeling and a stable switching function even in a particularly-high-stroke type push-button switch, and to provide a push-button switch. <P>SOLUTION: This movable contact structure 2, 30 or 33 for this push-button switch is provided with: an elastic movable contact plate 4 having dome parts 4a and 4b and base parts 4c formed in peripheral parts of the dome parts, and inversely deformable by a pressing operation; and an insulation sheet 3, 31 or 33 stuck to the dome outside surface side of the movable contact plate; and is characterized in that the insulation sheet has window holes 5, 32 or 35 for suppressing a stress action by the insulation sheet on the outside surface of the dome parts of the elastic movable contact plate. This application is characterized by composing the push-button switch by incorporating the movable contact structure 2, 30 or 33 therein. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a movable contact structure and a pushbutton switch including the movable contact structure, and more particularly to a movable contact structure and a pushbutton switch suitable for improving switching characteristics of a high-stroke type dome-shaped movable contact built-in pushbutton switch.

  In recent years, the fields of various electronic devices have been required to be reduced in size, thickness, and weight, and the same applies to pushbutton switches used for operation switches such as function operation buttons, numeric keys, and keyboards of these electronic devices. There is an increasing demand. An example of a conventional pushbutton switch with a built-in dome-shaped movable contact that meets this requirement will be described with reference to FIG.

  That is, FIG. 5A shows a state when the pushbutton switch is not operated (opened), and FIG. 5B is a cross-sectional view showing a state when the pushbutton switch is turned on (pressed). The substrate 51 serving as a support is composed of a printed wiring board such as RPC or FPC. On the upper surface of the substrate 51, an annular first fixed electrode 52 and a disk-shaped second fixed electrode 53 are arranged coaxially and spaced apart from the inner side of the ring.

  The elastic movable contact plate 54 disposed opposite to the first and second fixed electrodes 52 and 53 is an elastic metal plate formed so as to have a circular dome portion as a main portion and a pedestal portion around the periphery of the dome. It is configured. The pedestal at the periphery of the dome is overlapped along the ring of the first fixed contact 52, and the dome is arranged in a direction that protrudes upward so that its inner surface is separated from the second fixed contact 53.

  The insulating sheet 55 bonded to the entire outer surface of the dome of the elastic movable contact plate 54 is composed of an adhesive sheet having a thickness of about 50 μm made of a material such as polyethylene terephthalate (PET) or polyimide (PI). The plate 54 is supported on the fixed contacts 52 and 53 in a state where the plate 54 can be elastically deformed.

  Therefore, as shown in FIG. 5B, when the central portion of the dome of the elastic movable contact plate 54 is pressed down (pressed), the elastic movable contact plate 54 is inverted and bent, and the inner surface of the dome portion is the second. By contacting the fixed contact 53, the first and second fixed contacts are connected (turned on). Next, when the pressing is released, the elastic movable contact plate 54 is automatically restored like a leaf spring and returns to an open (off) state as shown in FIG. Further, in order to avoid the influence of the compression action of the air in the dome during the pressing operation of the dome, a ventilation hole 56 having a diameter of about 1 mm is formed in the insulating sheet 55 in a part around the pedestal portion of the elastic movable contact plate 54. Is provided. The structure of the push button switch with a built-in dome-shaped movable contact as described above can also be seen in Patent Document 1 below.

  By the way, when the elastic movable contact plate 54 is used, for example, in an electronic device such as a mobile phone, one having an outer diameter of 4 to 6 mm and a height of 0.2 to 0.3 mm is often used. However, depending on the applied electronic device, the elastic movable contact plate 54 may have a high stroke type dome shape having an outer diameter of 10 mm or more and a height of about 0.7 mm, for example.

  In this type of switch, as one of its switching characteristics, a characteristic relating to the click feeling of the elastic movable contact plate 54 is an important factor. FIG. 4 is a load (N) -displacement (mm) characteristic curve diagram for explaining the click characteristics, and the vertical axis indicates the pressure that presses the top of the dome portion against the second fixed contact 53 from the open state. The amount of load (N) is shown, and the horizontal axis shows the amount of displacement (operation movement) (mm) reaching the second fixed contact 53 at the top of the dome.

  The characteristic curve 41 in FIG. 4 is obtained when the high-stroke type dome-shaped elastic movable contact plate is incorporated in place of the elastic movable contact plate 54 of the conventional pushbutton switch shown in FIG. The characteristic curve 42 shows the characteristics of a single unit that is the high-stroke type elastic movable contact plate itself.

  In any characteristic curve, each dome portion is deformed so that the displacement amount increases as the load amount increases. When the load amount reaches the maximum value P1 (Pa), buckling reversal occurs, and the load amount However, when the load amount reaches the minimum value P2 (Pb), the inner surface of the dome portion comes into contact with the second fixed contact 53. After reaching the minimum value, the displacement amount is small and the inner surface of the dome portion advances to a state where it is pressed against the second fixed contact 53.

  In a high-stroke type dome-shaped elastic movable contact plate in which an insulating sheet is adhered to the entire outer surface, as indicated by the characteristic curve 41, the amount of pressure applied to the movable contact plate during switch operation is inherently The stroke until switching is shorter than the value of. Therefore, the conventional high stroke type switch cannot maintain the characteristic (characteristic curve 42) inherent to the high stroke type contact plate alone, and the desired click feeling cannot be obtained. There is.

The cause of such problems is that the maximum value Pa and the click rate η2 are reduced because the higher the dome height of the high stroke type movable contact plate is, the more the insulating sheet adhered to the outer surface of the dome part. Crushing stress acts on the dome part of the movable contact plate due to the internal contraction stress of the insulating sheet due to the reaction against the extension of 55, and the dome height after the switch assembly is reduced below the original height, and the height is set as desired. This is thought to be because it cannot be maintained.
International Publication Number WO 2004/025677

  The present invention has been made in order to solve the above-described problems of the prior art, and in particular, a movable contact structure having an excellent click feeling and capable of performing a stable switching function even in a high stroke type pushbutton switch. And a pushbutton switch.

  The movable contact structure for a pushbutton switch according to claim 1 has an elastic movable contact plate that has a dome portion and a pedestal portion formed on a peripheral edge portion of the dome portion and can be inverted and deformed by a pressing operation, An insulating sheet attached to the outer surface of the dome of the movable contact plate, and the insulating sheet has a window hole that suppresses the stress action of the insulating sheet on the outer surface of the dome portion of the elastic movable contact plate. To do.

  According to a second aspect of the present invention, in the movable contact structure according to the first aspect, the pedestal portion of the movable contact plate has a shape having a plurality of legs formed on the periphery of the dome portion. .

  According to a third aspect of the present invention, in the movable contact structure according to the first or second aspect, the window hole that suppresses the stress action entirely exposes at least the outer surface of the dome portion of the movable contact plate. And an inner peripheral edge portion of the insulating sheet along the window hole is bonded to an edge portion of the pedestal portion.

  According to a fourth aspect of the present invention, in the movable contact structure according to the first or second aspect, the insulating sheet is bonded over the outer surfaces of the dome portion and the pedestal portion of the movable contact plate, and the stress is applied. The said window hole which suppresses an effect | action is comprised by forming a several hole group in the bonding part of the said insulating sheet, It is characterized by the above-mentioned.

  According to a fifth aspect of the present invention, there is provided the push button switch according to the first aspect of the present invention, the first fixed contact and the second fixed contact that are arranged in parallel with each other on the support, the dome portion that is spaced apart and opposed to the second fixed contact, and the A movable contact structure configured by bonding an insulating sheet over the outer surface side of the dome portion of the elastic movable contact plate having a pedestal portion overlaid on the first fixed contact and the support. The structure is configured by the movable contact structure according to any one of claims 1 to 4.

  According to a sixth aspect of the present invention, in the pushbutton switch according to the fifth aspect of the present invention, the insulating sheet includes an electronic component that is arranged on the support body and spaced apart from the first fixed contact and the second fixed contact. Has a relief hole for the electronic component, and the relief hole of the insulating sheet and the window hole for suppressing the stress action are formed by simultaneous punching of the insulating sheet.

  According to the push button switch and the movable contact structure of the present invention, the movable contact structure is bonded to the dome outer surface side of the elastic movable contact plate having a dome portion and a pedestal portion formed on a peripheral portion of the dome portion. The insulating sheet has a window hole that suppresses the stress action of the insulating sheet on the outer surface of the dome portion of the elastic movable contact plate. Therefore, the elastic movable contact plate is hardly subjected to the crushing stress action by the insulating sheet, and maintains the original size and function manufactured with a predetermined dome outer diameter and height. Can be installed or installed in the switch. Therefore, when the push button is operated, the elastic movable contact plate has the original excellent click characteristics based on the design, and the switching function is stabilized, so that the on / off signal can be reliably transmitted to the peripheral devices.

  Examples 1 to 3 as embodiments of a movable contact structure and a push button switch according to the present invention will be described below with reference to FIGS. Moreover, the same code | symbol attached | subjected to each component between each figure shows that it is the same structure.

(Example 1):
FIG. 1 is a partially exploded schematic perspective view showing an overall image in which a plurality of pushbutton switches according to the first embodiment of the present invention are arranged. FIG. 2A is an enlarged plan view of one unit body of the movable contact structure of the pushbutton switch, and FIG. 2B is a cross-sectional view of the movable contact structure taken along the line AA of FIG. It is sectional drawing which shows the unit body of a pushbutton switch containing.

The flat support 1 is composed of a printed wiring board such as RPC or FPC, and a plurality of sets of fixed contact pairs and various electronic devices mounted thereon are arranged on the upper surface thereof to arrange a plurality of pushbutton switches. A conductive wiring layer for components is formed by patterning (details will be described later).
The movable contact structure 2 disposed on the surface of the support 1 includes an insulating sheet 3 that covers substantially the entire surface of the support 1 and a plurality of domes respectively disposed corresponding to the plurality of sets of fixed contact pairs. It is comprised by the integral structure with the elastic elastic contact plate 4 of a shape.

  The insulating sheet 3 is composed of an adhesive sheet having a thickness of about 50 μm made of a flexible resin material such as polyethylene terephthalate (PET) or polyimide (PI), and is opposed to the main dome of each elastic movable contact plate 4. For example, a plurality of circular window holes 5 formed so as to penetrate the positions are provided.

  And the inner peripheral edge part along each window hole 5 of the said insulating sheet 3 is bonded together by the adhesion | attachment to the outer surface of the dome peripheral part of each said elastic movable contact plate 4, and the movable contact structure 2 of the said integral structure is comprised. . Each window hole 5 functions so as not to apply a stress (dome crushing) load by the insulating sheet to the outer dome surface of each elastic movable contact plate 4.

  On the lower surface of the insulating sheet 3 that is not in contact with the movable contact plate 4, a release sheet is attached in a state before the switch is assembled, and the release sheet attaches each movable contact plate 4 to the support 1. The insulating sheet 3 is adhered to almost the entire upper surface of the support 1.

  The push button operation panel 10 disposed above the movable contact structure 2 includes a flexible panel 11 made of, for example, an insulating rubber sheet, and a plurality of push button portions 12, and the plurality of push button portions 12 are It is provided on the panel 11 corresponding to the arrangement of the plurality of elastic movable contact plates 4 (details will be described later). Further, a key display code (not shown) is displayed on the surface of the push button portion 12.

  Meanwhile, a plurality of electronic components 20 electrically connected to a part of the wiring layer are mounted on the support 1, and these electronic components 20 correspond to the movable contact plates 4. It comprises LED elements arranged in parallel, and is used as side view illumination for each key display code of the plurality of pushbuttons 12. A plurality of escape holes 21 corresponding to the LED elements 20 are formed in the insulating sheet 3.

  The plurality of window holes 5 and the plurality of escape holes 21 for electronic parts of the movable contact structure 2 are formed by simultaneously punching the insulating sheet 3 after defining a push button switch arrangement pattern and an electronic part arrangement pattern. The manufacturing process has been simplified. Although the push button operation panel 10 is illustrated as being far away from the support 1 upward, it is necessary for each movable contact plate 4 to perform its switching function by the operation of the push button portion 12. It is supported and fixed on the support 1 with a small interval (not shown).

  Next, the structure of the movable contact structure in this embodiment and the unit of a push button switch using the same will be described in detail with reference to FIG.

  On the upper surface of the printed wiring board support 1 (see FIG. 2B), the annular first fixed electrode 25 and the inner ring are spaced apart and coaxially arranged by wiring layer patterning. A disc-shaped second fixed electrode 26 is formed.

  Here, the elastic movable contact plate 4 of the movable contact structure 2 disposed on the first and second fixed electrodes 25 and 26 is made of an elastic metal plate such as stainless steel or phosphor bronze as described above. Molded into a stroke type dome. The elastic movable contact plate 4 includes a circular or spherical dome central part 4a as a main part thereof, an annular dome peripheral part 4b continuous with the peripheral edge of the dome central part 4a, and an outer peripheral edge of the dome peripheral part 4b. A plurality of (four) leg-shaped pedestal portions 4c that are partially continuous in, for example, a cross shape in four directions.

  The dome central portion 4a, the dome peripheral portion 4b, and the leg-shaped pedestal portion 4c are formed with annular bent ridgelines 4d and 4e that are slightly bent between the respective portions, and the elastic movable contact plate 4 is It is molded so as to have a dome shape as a whole. The elastic movable contact plate 4 has, for example, an outer diameter (a distance between the outermost edges of the two pedestal portions 4c facing each other at the center of the dome) of 10 mm and a dome height (the lowermost surface of the pedestal portion 4c and the dome central portion). The distance from the outermost surface of 4a) is a dimension of a high stroke type of 0.6 to 0.7 mm.

  The elastic movable contact plate 4 overlaps the lower end of the pedestal portion 4c along the ring of the first fixed electrode 25, and protrudes upward so that the inner surface of the dome central portion 4a is separated from the second fixed electrode 26. It is arranged in the direction.

  Therefore, when the top portion of the dome central portion 4a is pressed (pressed) toward the second fixed electrode 26, the pedestal portion 4c has a shape divided into legs, so that the movable contact plate No. 4, the pedestal 4c as a whole is formed in an annular shape, and elastic deformation easily occurs with a weaker pressing force, so that the pressing operation can be performed smoothly. Further, since the dome peripheral portion 4b and the bent ridge lines 4d and 4e are formed, the dome reversal deformation of the movable contact plate 4 is smoothly performed by buckling based on the bent ridge lines 4d and 4e. By such a smooth elastic deformation and dome reversal deformation of the movable contact plate 4, a high stroke switching operation of the movable contact plate 4 can be performed reliably and stably.

  And the inner peripheral edge part along the window hole 5 of the said insulating sheet 3 is piled up on the outer surface in the range of about 1 mm from the leg edge part of each said base part 4c located in the dome peripheral part of each said elastic movable contact plate 4 Are stuck together. Thus, each pedestal portion 4c has a shape having a notch between the legs, and the window hole 5 for suppressing the crushing load on each elastic movable contact plate 4 is provided. Since an air passage is formed in the inner and outer spaces of the dome, there is no need to provide a vent hole as described in the prior art.

  The push button operation panel 10 shown in FIG. 2B has the push button 12 provided on a part of the upper surface of a flexible panel 11 made of a flexible insulating rubber sheet, and the push button Corresponding to 12, an actuator (pressing element) 13 is provided so as to protrude from a part of the lower surface of the panel 11. The actuator 13 is disposed so as to be able to apply a pressing load to each dome central portion 4a of each of the plurality of elastic movable contact plates 4 for each push button operation.

  The movable contact structure 2 in the pushbutton switch of the first embodiment has substantially the same operating characteristics (click feel) as the characteristic curve 42 of the elastic movable contact plate 4 alone, as shown by the characteristic curve 43 in FIG. ) Is realized. That is, according to the pushbutton switch having the movable contact structure 2 of the first embodiment, each window hole 5 has a stress (dome crushing) caused by an insulating sheet on the outer dome surface of each elastic movable contact plate 4. ) It functions so as not to apply a load. The movable contact plate 4 can be incorporated in or attached to the pushbutton switch while maintaining the original size and function produced with a predetermined dome outer diameter and height. Therefore, when the push button is operated, the elastic movable contact plate has an original excellent click characteristic based on the design, its switching function is stabilized, and reliable on / off signal transmission to peripheral devices can be performed. Such an effect is particularly exhibited when the elastic movable contact plate 4 is of a high stroke type.

(Example 2):
In the second embodiment shown in FIG. 3A, the insulating sheet 31 of the movable contact structure 30 is made of the same material as the insulating sheet 3 of the first embodiment, but penetrates the insulating sheet 31. The formed window hole 32 is formed in, for example, an octagonal polygonal shape. In this way, the protection range can be expanded so as not to expose the wiring layer of the printed circuit board constituting the support as much as possible as compared with the circular window hole 5 in the first embodiment. In this way, the shape of the window hole 32 may be changed according to the purpose such as protection.

(Example 3):
In the third embodiment shown in FIG. 3B, the insulating sheet 34 of the movable contact structure 33 is made of the same material as that of the insulating sheet 3 of the first embodiment. Board 4
The entire outer surface of the dome is bonded together. A plurality (16 in the drawing) of window holes 35 are formed through the surface of the insulating sheet 34 that overlaps the outer surface of the dome of the elastic movable contact plate 4. Also, some of the plurality of window holes 35 are arranged so as to straddle outwardly on the leg side edges of the pedestal portion 4c of each elastic movable contact plate 4. It can also function as a road.

  The plurality of window holes 35 can weaken the internal contraction stress of the portion of the insulating sheet 34 bonded to the outer surface of the dome portion of the movable contact plate 4, so that the elastic movable contact plate 4 is formed by the insulating sheet 34. Incorporated into a pushbutton switch as shown in FIG. 1 while maintaining the original dimensions and function of the movable contact plate 4 manufactured with a predetermined dome outer diameter and height with almost no crushing stress. Or it can be installed. Therefore, when the push button is operated, the elastic movable contact plate has the original excellent click characteristics based on the design, and the switching function is stabilized, so that the on / off signal can be reliably transmitted to the peripheral devices. Further, since the insulating sheet 34 is widely bonded to the outer surface of the dome of the movable contact plate 4, the supporting force of the movable contact plate 4 and the protection range of the wiring layer of the printed circuit board are the same as those of the first and second embodiments. Can be larger than the case.

  By the way, the window holes 5 and 32 in the first and second embodiments expose the entire base portions of the dome central portion 4a, the dome peripheral portion 4b and the pedestal portion 4c of the elastic movable contact plate 4, so that the outer surface of the dome portion is exposed. The stress action is suppressed so that the stress action (dome crushing action) by the insulating sheets 3 and 31 hardly occurs. On the other hand, the plurality of window holes 35 in Example 3 suppress the stress action so as to weaken the internal contraction stress on the outer surface of the dome portion of the movable contact plate 4 of the insulating sheet 34.

  The number of legs of the pedestal 4c of the elastic movable contact plate 4 is not limited to four and may be increased or decreased. The elastic movable contact plate 4 in the embodiment includes the dome central portion 4a and the dome peripheral portion 4b. However, depending on the degree of the click function required for the elastic movable contact plate, the dome peripheral portion may be omitted and the dome center portion may be used.

It is a partially exploded schematic perspective view for showing the whole picture which has arranged a plurality of pushbutton switches concerning Example 1 of the present invention. It is a figure for demonstrating the movable contact structure and pushbutton switch which concern on Example 1 of this invention, (a) is an enlarged plan view of the unit body of the movable contact structure, (b) is FIG. It is sectional drawing which shows the unit body of a pushbutton switch containing the cross section of the movable contact structure in alignment with the AA of a). It is a figure for demonstrating one unit body of the movable contact structure which concerns on the other Example of this invention, (a) is an enlarged plan view of one unit of the movable contact structure which concerns on Example 2 of this invention. (B) is an enlarged plan view of one unit body of the movable contact structure according to Embodiment 3 of the present invention. It is a characteristic curve figure for demonstrating the load-displacement characteristic of a movable contact structure and a pushbutton switch. It is a figure for demonstrating the conventional movable contact structure, (a) is sectional drawing of the conventional movable contact structure, (b) is sectional drawing which shows the state at the time of ON operation of the movable contact structure. .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Support body 2,30,33 Movable contact structure 3,31,34 Insulating sheet 4 Elastic movable contact plate 5,32,35 Window hole 10 Pushbutton operation panel 11 Panel 12 Pushbutton part 13 Actuator 20 Electronic component 21 Escape hole

Claims (6)

  An elastic movable contact plate having a dome portion and a pedestal portion formed on a peripheral portion of the dome portion and capable of being inverted and deformed by a pressing operation; and an insulating sheet attached to the dome outer surface side of the movable contact plate, A movable contact structure for a pushbutton switch, wherein the insulating sheet has a window hole that suppresses the stress action of the insulating sheet on the outer surface of the dome portion of the elastic movable contact plate.   2. The movable contact structure according to claim 1, wherein the pedestal portion of the movable contact plate has a plurality of legs formed on the periphery of the dome portion.   3. The movable contact structure according to claim 1, wherein the window hole that suppresses the stress action has a hole diameter that exposes at least the outer surface of the dome portion of the movable contact plate, and the insulating sheet. The movable contact structure according to claim 1, wherein an inner peripheral edge along the window hole is bonded to an edge of the pedestal.   The movable contact structure according to claim 1 or 2, wherein the insulating sheet is bonded to each outer surface of the dome portion and the pedestal portion of the movable contact plate, and the window hole for suppressing the stress action is: A movable contact structure comprising a plurality of hole groups formed in a bonded portion of the insulating sheet.   A first fixed contact and a second fixed contact juxtaposed apart from each other on the support; a dome portion spaced apart from and opposed to the second fixed contact; and a pedestal stacked on the first fixed contact. A movable contact structure configured by bonding an insulating sheet over the outer surface side of the dome portion of the elastic movable contact plate and the support, and the movable contact structure is any one of claims 1 to 4. A pushbutton switch comprising the movable contact structure according to one claim. 6. The pushbutton switch according to claim 5, further comprising: an electronic component disposed on the support body and spaced apart from the first fixed contact and the second fixed contact, wherein the insulating sheet has an escape hole for the electronic component. And the escape hole of the insulating sheet and the window hole for suppressing the stress action are formed by simultaneous punching of the insulating sheet.

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