CN101206964B - Movable contact unit and switch using the same - Google Patents

Abstract

The present invention relates to a movable contact body and a switch using the same. The movable contact body comprises: a base sheet made of polyurethane resin, a dome-shaped movable contact made of a metal sheet, and a pressing protrusion. The movable contact is held on the first surface side of the base sheet. The pressing protrusion is formed on the second surface of the base sheet and is arranged at a position corresponding to the dome-shaped vertex of the movable contact.

Description

Movable contact body and switch using it

technical field

The present invention relates to a movable contact body used in the operation of various electronic devices and a switch using the same. the

Background technique

In recent years, there has been a demand for an easy-to-use and inexpensive operation unit in various electronic devices, especially mobile terminal devices such as mobile phones. Such a conventional movable contact body constituting an operation unit and a switch using the same will be described with reference to FIGS. 9 and 10 . the

FIG. 9 is a cross-sectional view of a conventional movable contact body, and FIG. 10 is a cross-sectional view of a switch using the movable contact body shown in FIG. 9 . The movable contact body 30 has a base plate 31 , a movable contact 33 , and a pressing protrusion 34 . The base sheet 31 is made of a polyethylene terephthalate (PET) resin film. An adhesive layer 32 is provided on the lower surface of the base sheet 31 . The movable contact 33 is formed of an elastic metal thin plate such as stainless steel. The movable contact 33 is formed in a dome shape with an open bottom and swells upward. The dome-shaped upper surfaces of the plurality of movable contacts 33 are bonded by the adhesive layer 32 and held at predetermined positions on the base sheet 31 . The pressing protrusion 34 is fixed to the upper surface of the base sheet 31 at a position corresponding to the dome-shaped apex of the movable contact 33 with an adhesive 35 . Most of the pressing protrusion 34 is made of PET resin. the

The adhesive 35 is an ultraviolet curable adhesive composed of urethane acrylate. A resin layer 31A and a resin layer 34A made of ester-based resin are respectively provided on the fixed surfaces of the base sheet 31 and the pressing protrusion 34 . the

A spacer 36 made of an insulating film is attached to the lower surface of the base sheet 31 via an adhesive layer 32 , so that the movable contact body 30 can be transported and stored. the

When using the movable contact body 30, the movable contact body 30 with the spacer 36 peeled off, as shown in FIG. ) 40 on. On the upper surface of the substrate 40 , a plurality of pairs of fixed contacts including a central fixed contact 41 and an outer fixed contact 42 are arranged. The fixed contacts are respectively provided at positions corresponding to the movable contacts 33 . The switch 50 is configured by attaching the movable contact body 30 to the substrate 40 in this way. the

In the switch 50 , the dome-shaped apex of the movable contact 33 faces the central fixed contact 41 with a gap therebetween, and the outer peripheral lower end is placed on the outer fixed contact 42 . The movable contact 33 and the pair of fixed contacts 41 and 42 constitute one switch, and the switch 50 for an operation panel including a plurality of switches is formed as a whole. In addition, an operation button 43 of the electronic device is disposed on the base sheet 31 at a position corresponding to the upper side of the pressing protrusion 34 . the

Next, the operation of the switch 50 using the conventional movable contact body 30 configured in this way will be described. First, when the user presses the operation button 43 with a finger or the like, the operation button 43 descends downward. Next, a pressing force is applied to the pressing protrusion 34 that is in contact with the operation button 43 . Furthermore, this pressing force is applied to the dome-shaped apex portion of the movable contact 33 through the base sheet 31 . Then, when the force becomes greater than the pressing force of the elastic rebound of the movable contact 33 , the dome-shaped portion of the movable contact 33 elastically rebounds in a downwardly swelled direction with a click feeling. Due to this rebound, the lower surface of the dome-shaped apex portion comes into contact with the central fixed contact 41 , and the fixed contacts 41 , 42 are electrically connected via the movable contact 33 . the

When the pressing force applied to the operation button 43 is released, the pressing force applied to the movable contact 33 by the pressing protrusion 34 and the base sheet 31 becomes smaller. When this force becomes smaller than the rebound restoring force of the elastically rebounded dome-shaped portion of the movable contact 33 , the movable contact 33 returns to the original dome shape with a click feeling. Therefore, the movable contact 33 is separated from the central fixed contact 41 , and the fixed contacts 41 and 42 are electrically isolated. the

In addition, the pressing protrusion 34 is provided so that the center portion of the dome-shaped apex portion of the movable contact 33 can always be pressed even when the operation button 43 is pressed at a position shifted from the center. Thereby, the click feeling accompanying the bouncing and returning of the movable contact 33 during operation is stabilized, and a good operating feeling is obtained. the

As the base sheet 31, PET resin is generally used. The breaking strength of PET resin is 200MPa-260MPa, and the breaking elongation is 80%-140%. That is, PET resin is a relatively hard material. Therefore, the click feeling when the movable contact 33 rebounds elastically is reduced. This is because, when the movable contact 33 is pressed by the base sheet 31 made of PET resin during operation, a force to deform the base sheet 31 itself is required. This tendency is remarkable especially in the case where an electroluminescent element (hereinafter referred to as an EL element) is formed on the lower surface of the base sheet 31 . the

In order to prevent the click feeling from being degraded, the base sheet 31 is formed relatively thin. That is, the thickness of the base sheet 31 is about 25 μm to 75 μm. If it is made thinner, the base sheet 31 may be damaged when the EL element is attached to the substrate 40 by printing. Therefore, there is a limited effect in improving the click feeling when the switch 50 is pressed. the

Contents of the invention

The present invention provides a movable contact body which obtains a light click feeling and can be operated with good tactile feeling, and a switch using the same. The movable contact body of the present invention has a base sheet made of polyurethane resin, a movable contact made of a dome-shaped metal sheet, and a pressing protrusion. The movable contact is held on the first face side of the base sheet. The pressing protrusion is formed on the second surface of the base sheet and arranged at a position corresponding to the dome-shaped apex of the movable contact. By forming the base sheet with polyurethane in this way, it is possible to prevent a decrease in the click feeling. the

Description of drawings

FIG. 1 is a cross-sectional view of a movable contact body according to an embodiment of the present invention. the

Fig. 2 is an exploded perspective view of the movable contact body shown in Fig. 1 . the

Fig. 3 is a cross-sectional view of a switch using the movable contact body shown in Fig. 1 . the

Fig. 4 is a cross-sectional view showing an operating state of the switch shown in Fig. 3 . the

5 is a cross-sectional view of another movable contact body according to the embodiment of the present invention. the

Fig. 6 is an enlarged sectional view of the movable contact body shown in Fig. 5 . the

Fig. 7 is a cross-sectional view of a switch using the movable contact body shown in Fig. 5 . the

8 is a cross-sectional view of another movable contact body according to the embodiment of the present invention. the

Fig. 9 is a sectional view of a conventional movable contact body. the

Fig. 10 is a cross-sectional view of a switch using the movable contact body shown in Fig. 9 . the

Detailed ways

FIG. 1 is a sectional view of a movable contact body according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view thereof. Fig. 3 is a cross-sectional view of a switch using the movable contact body shown in Fig. 1, and Fig. 4 is a cross-sectional view showing its operating state. The movable contact body 20 has a base sheet 1 , a movable contact 3 and a pressing protrusion 4 . the

The base sheet 1 is made of a polyurethane resin film. On the upper surface of the base sheet 1 , unlike conventional ones, no ester-based resin layer is provided. An adhesive layer 2 of acrylic, butyl rubber, or the like is provided on the entire lower surface (first surface) of the base sheet 1 . The circular movable contact 3 is formed of an elastic metal thin plate such as copper alloy, copper, or stainless steel. The movable contact 3 is formed in a dome shape with an open bottom and swells upward. When the movable contact 3 receives a predetermined pressing force, it elastically rebounds with a click feeling, and elastically returns to the original dome shape with the click feeling when the pressing force is released. the

The dome-shaped upper surfaces of the plurality of movable contacts 3 are adhered to and held at predetermined positions on the base sheet 1 by the adhesive layer 2 . The columnar pressing protrusion 4 is fixed to the upper surface (second surface) of the base sheet 1 at a position corresponding to the dome-shaped top of the movable contact 3 with an adhesive 5 . The pressing protrusion 4 is formed by punching a resin thin plate as a raw material. Most of the pressing protrusions 4 are made of PET resin. the

The adhesive 5 is an ultraviolet curable adhesive composed of urethane acrylate. A resin layer 4A made of an ester-based resin is provided on the fixing surface of the pressing protrusion 4 . the

A spacer 6 made of an insulating film such as PET having a thickness of about 50 to 100 μm is attached to the lower surface of the base sheet 1 via an adhesive layer 2 , so that the movable contact body 20 can be transported and stored. The surface of the separator 6 is subjected to a release treatment. By using the spacer 6 , the lower surface of the movable contact 3 is protected and oxidation of the surface is prevented, and foreign matter and the like are prevented from adhering to the adhesive layer 2 . That is, as shown in FIG. 1 , the entire lower surface of the base sheet 1 is covered with the partition 6 , and the movable contact 3 is sandwiched between the base sheet 1 and the partition 6 for transport and storage. the

When using the movable contact body 20, the movable contact body 20 with the spacer 6 peeled off is attached to the wiring substrate (hereinafter referred to as the substrate) through the adhesive layer 2 on the lower surface of the base sheet 1 as shown in FIG. 10 on. The substrate 10 is made of paper phenol, epoxy resin mixed with glass, etc., and a plurality of wiring patterns are formed with copper foil or the like on the upper surface and/or the lower surface. In addition, on the upper surface of the substrate 10, a plurality of pairs of fixed contacts 14 are arranged, in which a substantially circular central fixed contact 11 and a substantially horseshoe-shaped outer fixed contact 12 form a pair. The fixed contacts 14 are respectively provided at positions corresponding to the movable contacts 3 . That is, the movable contact 3 of the movable contact body 20 faces the fixed contact 14 of the substrate 10 and is attached to the substrate 10 through the lower surface side of the base sheet 1 to form the switch 21 .

The switch 21 is arranged such that the dome-shaped apex of the movable contact 3 faces the central fixed contact 11 with a gap therebetween, and the outer peripheral lower end is placed on the outer fixed contact 12 . The movable contact 3 and the fixed contact 14 constitute one switch, and the switch 21 for an operation panel including a plurality of switches is formed as a whole. In addition, an operating body 13 made of insulating resin is disposed on the base sheet 1 at a position corresponding to the upper side of the pressing protrusion 4 . A pressing portion 13A protruding from the lower surface of the operating body 13 is in contact with the pressing protrusion 4 . In this state, the switch 21 is incorporated into an electronic device (not shown). The central fixed contact 11 and the outer fixed contacts 12 are connected to a circuit (not shown) of the electronic device through a wiring pattern, a connector, and the like. the

Next, the operation of the switch 21 using the movable contact body 20 of this embodiment configured in this way will be described with reference to FIG. 4 . First, when the user presses the operation body 13 with a finger or the like, the operation body 13 descends downward. Next, a pressing force is applied to the pressing protrusion 4 in contact with the pressing portion 13A of the operation body 13 . Furthermore, this pressing force is applied to the dome-shaped apex portion of the movable contact 3 through the base sheet 1 . Then, when this force becomes greater than the pressing force of the elastic rebound of the movable contact 3 , the dome-shaped portion of the movable contact 3 elastically rebounds in a downwardly swelled direction with a click feeling. Due to this rebound, the lower surface of the dome-shaped apex portion comes into contact with the central fixed contact 11 , and the fixed contacts 11 and 12 are brought into electrical conduction through the movable contact 3 . the

When the pressing force applied to the operating body 13 is released, the pressing force applied to the movable contact 3 by the pressing protrusion 4 and the base sheet 1 becomes smaller. When this force becomes smaller than the rebound restoring force of the elastically rebound dome-shaped portion of the movable contact 3, the movable contact 3 returns to the original dome shape with a click feeling. Therefore, the movable contact 3 moves away from the central fixed contact 11, and the fixed contacts 11, 12 return to an electrical insulation state. the

In addition, the pressing protrusion 4 is provided so that the center of the dome-shaped apex of the movable contact 3 can always be pressed even when the pressing is performed at a position shifted from the center of the operation body 13 . Thereby, the click feeling accompanying the bouncing and returning of the movable contact 3 during operation is stabilized, and a good operating feeling is obtained. the

In this embodiment, as the base sheet 1 , a polyurethane resin sheet having a breaking strength of 2 MPa to 10 MPa and a breaking elongation of 300% to 1000%, which is softer than PET or the like, and has ductility and elasticity, is used. That is, the base sheet 1 can be deformed with a small force. Therefore, when the operating body 13 is pressed to apply a pressing force to the movable contact 3 , the elastic deformation of the dome-shaped portion is similar to a state in which the movable contact 3 is directly pressed alone. The result is a crisp and light click. the

There is a click rate as an index for evaluating the click feeling with a measured value. The pressing force (P1) immediately before the elastic rebound when pressing, and the pressing force (P2) immediately after the elastic recovery from the elastic rebound state when the pressing force is released were measured. Next, divide P1 by the difference (D) between P1 and P2. This value is expressed as a percentage, and the click rate is obtained. the

When the base sheet made of PET resin is used, the click rate is reduced by 3% to 6% compared to using the movable contact 3 alone. On the other hand, in the case of using the base sheet 1 made of polyurethane resin, the decrease in the click rate was maintained at 1% to 2%. the

In addition, since the adhesive 5 and the base sheet 1, which is the member to be bonded, are made of the same polyurethane-based resin, the affinity between the bonding interfaces is high. Due to the improved affinity, it is not necessary to provide a resin layer on the bonding surface of the base sheet 1, and the preparation of the base sheet 1 as a component is relatively easy. In addition, since the ultraviolet curable adhesive 5 containing urethane acrylate can be cured in a short time, it is suitable from the viewpoint of production work. the

In addition, preferably, the base sheet 1 is formed of thermoplastic polyurethane (TPU). In addition, TPU having a thickness of 15 μm to 100 μm, more preferably about 50 μm, can be used for the base sheet 1 . the

In addition, in the present embodiment, the pressing protrusion 13 is formed of PET resin which is a material harder than the base sheet 1 . Therefore, when the operation body 13 is pressed, even if the center of the pressing portion 13A and the movable contact 3 is somewhat misaligned, the deflection of the pressing protrusion 4 itself is small. The elastic rebound of the movable contact 3 is reliably performed by pressing the dome-shaped apex of the dome. In addition, the movable contact 3 can be operated with a good tactile feeling. the

In addition, when the pressing protrusion 4 is formed of PET resin, it is preferable to provide the resin layer 4A made of ester-based resin on the fixing surface of the pressing protrusion 4 as described above. In this way, the adhesive strength of the pressing protrusion 4 can be improved. the

Next, a movable contact body having another structure according to the embodiment of the present invention will be described with reference to FIGS. 5 to 7 . 5 is a sectional view of another movable contact body according to the embodiment of the present invention, FIG. 6 is an enlarged sectional view of the movable contact body shown in FIG. 5 , and FIG. 7 is a switch using the movable contact body shown in FIG. 5 . cutaway view. the

The movable contact body 20A shown in FIG. 5 differs from the movable contact body 20 shown in FIG. 1 in the following two points. First, instead of the base sheet 1 , a light-transmitting and flexible base sheet 1A is used. In addition, an electroluminescence element (hereinafter, EL element) 7 is formed on the lower surface of the base sheet 1A. Also, an adhesive layer 2 is formed on the lower surface of the EL element 7 . That is, the EL element 7 is provided between the base sheet 1A and the movable contact 3 . the

As shown in FIG. 6 , the EL element 7 has a light-transmitting electrode layer 71 , a luminous body layer 72 , a dielectric layer 73 , and a back electrode layer 74 . The light-transmitting electrode layer 71 is formed by printing and dispersing a light-transmitting synthetic resin such as indium tin oxide or a conductive resin such as polyethylenedioxythiophene on the lower surface of the base sheet 1A. The luminous material layer 72 is formed by printing synthetic resin such as fluorine-containing rubber on the lower surface of the light-transmitting electrode layer 71 and dispersing phosphors such as zinc sulfide as a light-emitting base material. The dielectric layer 73 is formed by printing and dispersing a synthetic resin such as barium titanate on the lower surface of the phosphor layer 72 . The back electrode layer 74 is formed by printing resin dispersed with silver, carbon, etc. on the lower surface of the dielectric layer 73 . In addition, an insulating layer such as epoxy resin or polyester resin may be provided to cover these layers. The light-transmitting electrode layer 71 and the back electrode layer 74 are connected to a circuit (not shown) of an electronic device through a wiring pattern, a connector, and the like. the

In this configuration, each function of the electronic device is switched in accordance with the electrical conduction/disconnection of the fixed contact 14 caused by the pressing operation of the operating body 13 . At the same time, when a voltage is applied from the circuit of the electronic device to the light-transmitting electrode layer 71 and the back electrode layer 74 of the EL element 7, the luminous material layer 72 emits light. This light illuminates the operation body 13 from below through the base sheet 1A. Therefore, even in a dark environment, for example, the user can easily recognize and operate the operation unit of the electronic device. the

In addition, as described above, the base sheet 1A is formed of a light-transmitting polyurethane resin. Therefore, even when the EL element 7 having a thickness of about 50 μm to 100 μm is formed on the lower surface of the base sheet 1A, the click feeling when the movable contact 3 bounces elastically is not impaired. Therefore, the user obtains a light click feeling, and can operate the switch 21A with a good tactile feeling. the

Furthermore, as shown in FIG. 8 , instead of the pressing protrusion 4 made of PET resin, a pressing protrusion 4B made of a material having the same hardness as or lower than that of the base sheet 1A may be used. The pressing protrusion 4B can be formed of the same type or grade of TPU resin or silicone resin as that of the base sheet 1A or with a lower hardness. In addition, the pressing protrusion 4B can be formed by punching a thin plate-shaped material with a thickness of about 100 μm to 250 μm. the

Compared with the case of using the pressing protrusion 4 made of PET resin, the pressing protrusion 4B itself presses the movable contact 3 while flexing, so that the user can obtain a good operating touch with a soft feeling. the

In addition, when the pressing protrusion 4B is formed of the same polyurethane resin as the base sheet 1A, it is not necessary to form the ester-based resin layer 4A on the lower surface on the side to be bonded like the pressing protrusion 4 made of PET resin. In this way, the affinity between the adhesive interfaces is improved by using the same polyurethane-based resin as the adhesive 5 and the pressing protrusion 4B as the adhered member. As a result, the pressing protrusion 4B is fixed in a firmly bonded state. the

In addition, when the base sheet 1A and the pressing protrusion 4B have elasticity, that is, when the switch is configured by attaching the movable contact body 20B as shown in FIG. That is, with respect to the dimension from the upper surface of the substrate 10 to the lower surface position of the operating body 13, the height dimension of the movable contact body 20B as a whole, that is, from the lower surface of the adhesive layer 2 at the position attached to the substrate 10 The dimension to the upper surface of the pressing protrusion 4B is set slightly larger. Also, the assembly operation body 13 is in elastic contact with the pressing protrusion 4B. In this way, the difference in size generated during assembly is absorbed by the elasticity of the pressing protrusion 4B. Accordingly, it is possible to easily realize a high-quality switch for an operation panel without rattling of the operation body 13 . In addition, even if there is a slight gap between the lower surface of the operating body 13 and the upper surface of the pressing protrusion 4B, as long as there is the pressing protrusion 4B, it can be easily realized that the lower surface of the operating body 13 and the pressing protrusion caused by the pressing operation do not occur. High-quality switch for the operation panel with a bump sound on the upper surface of the protrusion 4B. the

In addition, in FIG. 8 , the movable contact body 20B provided with the EL element 7 has been described, but it is not limited to this, and the EL element 7 may not be provided, and the hardness equal to or lower than that of the base sheet 1A may be used. The pressing protrusion 4B made of material. In this case, if the non-light-transmitting base sheet 1A is used instead of the light-transmitting base sheet 1A, the cost is lower. the

In addition, the pressing protrusions 4 and 4B may be formed by printing instead of punching a thin plate. the

As described above, the movable contact body of the present invention and the switch using the same can be operated with good tactile feeling. The movable contact body and the switch using the same can be used for the operation of various electronic devices. the

Claims (13)

1. movable contact unit possesses:

Have first substrate thin plate with second polyurethane resin system of said first opposition side;

Remain in the travelling contact said first side, dome-type sheet metal system of said substrate thin plate; And

Said substrate thin plate said second, with the corresponding position of dome-shaped apex of said travelling contact on the push projection that forms.

2. movable contact unit according to claim 1, wherein,

Said substrate thin plate is by made from thermoplastic polyurethane resin.

3. movable contact unit according to claim 1, wherein,

Also have said first tack coat of going up, bond and keep said travelling contact that is located at said substrate thin plate.

4. movable contact unit according to claim 1, wherein,

Said substrate thin plate and said push projection are mutually bonding through the bonding agent of the ultraviolet hardening that is made up of urethane acrylate.

5. movable contact unit according to claim 1, wherein,

Said push projection is harder than said substrate thin plate.

6. movable contact unit according to claim 5, wherein,

Said push projection is by PETG system.

7. movable contact unit according to claim 6, wherein,

Said substrate thin plate and said push projection are mutually bonding through the bonding agent of the ultraviolet hardening that is made up of urethane acrylate,

It is the resin bed that resin constitutes that said push projection has by ester on by bonding face.

8. movable contact unit according to claim 1, wherein,

The hardness of said push projection is less than or equal to the hardness of said substrate thin plate.

9. movable contact unit according to claim 8, wherein,

Said push projection is by polyurethane resin system.

10. movable contact unit according to claim 8, wherein,

Said push projection is by thermoplastic polyurethane system.

11. movable contact unit according to claim 1, wherein,

Also possess the electroluminescent cell that is located between said substrate thin plate and the said travelling contact,

Said substrate thin plate is a transmitance.

12. a switch, wherein,

Possess: movable contact unit and substrate with fixed contact,

Said movable contact unit has: have first substrate thin plate with second polyurethane resin system of said first opposition side;

Remain in the travelling contact said first side, dome-type sheet metal system of said substrate thin plate; And

Said substrate thin plate said second, with the corresponding position of dome-shaped apex of said travelling contact on the push projection that forms,

Said movable contact unit with the said fixed contact of the said travelling contact of said movable contact unit and said substrate relatively to mode, said first side through said substrate thin plate is attached on the said substrate.

13. switch according to claim 12, wherein,

Also possess the electroluminescent cell that is located between said substrate thin plate and the said travelling contact,

Said substrate thin plate is a transmitance.

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