JPH09102240A - Two-piece cover member for pushbutton switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-piece cover member for a pushbutton switch, which has a pressing part that feels nice to fingertips when pressed and which is excellent in visibility and in productivity because of low cost. SOLUTION: This two-piece cover member for a pushbutton switch has a translucent upper cover member 1 consisting of one or more key top parts 3 each having a recess 4 in its bottom surface, a thin-walled part 5, and a base part 6. Also, the two-piece cover member is provided with a lower cover member 2 which consists of one or more projections 7 each having a mark 10 on its top surface; a thin-walled movable part 8; a base part 9; and a contact part 13 which bulges downwards from almost the center of the bottom surface of the projection 7. The upper cover member 1 is laid on top of the lower cover member 2 with the recess 4 fitted over the projection 7. In this case a horizontal clearance between the recess 4 in the upper cover member 1 and the projection 7 on the lower cover member 2 is 0 to +0.7mm, a clearance between them along their direction of height is 0 to +0.2mm, the bottom surface of the recess 4 in the upper cover member 1 has a surface roughness of 0.1 to 0.6μm, and the top surface of the projection 7 on the lower cover member 2 has a surface roughness of 0.8 to 1.7μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cover member for a push button switch used for an input device of any electronic equipment such as a computer, a remote controller, a musical instrument, a computer and the like.

[0002]

2. Description of the Related Art Operational switches are indispensable for various electronic devices used in various fields. Although various switches such as a toggle switch and a slide switch are known as the switch, a push-button switch is particularly popular because it is particularly noticeable. This push button switch used to be a mechanical push button switch that used multiple parts such as springs, but the number of parts has been reduced to reduce processing costs from about 20 years ago.
A cover member for a push button switch integrally formed with a rubber-like elastic body typified by silicone rubber has been preferred and used. However, in recent years, push-button switches have been developed in various fields, and consumer needs for design and performance are diversifying, so that a base material integrally molded with a rubber-like elastic body such as silicone rubber, which has been the mainstream in the past, has been developed. There is a decreasing need for a cover member for a push button switch having a structure having a code on the top surface of the key top portion. Consumers' demands for the performance of cover members for push button switches are mainly that the push operability is good and the visibility of characters is good (when used for portable devices, the visibility of the push button display is recognizable even in a dark place. Property is required), the visibility of characters is not lost even after long-term use, the design has a high-grade feeling, and it is inexpensive.

Since the cover member for a push button switch, which is integrally formed of a rubber-like elastic body, has an adhesive property peculiar to rubber on the top surface of the key top portion, especially during the hot and humid season of summer, the sticky feeling to the finger during operation is provided. It is shunned for the reason that it feels, and instead, a thin movable part / base part made of a rubber-like elastic body is bonded with a key top chip made of acrylic resin or polyester resin using a primer or the like, or Prepare a composition that can be integrally molded with silicone rubber consisting of multiple special resins mainly made of acrylic resin or polyester resin, and use this composition for the key top part, and only the key top part has high hardness (Shore D hardness). Is a resin body of 40 degrees or more), and the thin movable portion / base portion is made of a rubber-like elastic body.

Conventionally, on the top surface of the key top portion of the cover member for a push button switch, numbers, symbols, characters, symbols and the like (hereinafter, simply referred to as symbols) indicating guides for operating the push button switch are formed. Naturally, these symbols must be capable of adhering to the rubber-like elastic body or high-hardness resin body of the base material, and therefore, usually the same resin component as the resin component of the base material contains a colorant. Often marked by ink. Since the cover member for a push button switch in such a form cannot be used in a dark place, a cover member having a high visibility is used by the following method.
One is a pushbutton switch in which a luminous pigment or a self-luminous pigment is used as an ink and a symbol is marked by this, or the ink itself having a symbol is not luminous or self-luminous, but whose base material is luminous or self-luminous. It is a cover member for.
For others, the base material of the cover material for the push button switch is made of a translucent rubber-like elastic material, and the thickness of 30 ~
A cover member for a push button switch is formed by forming a 100 μm light-shielding layer, removing a part of it by a method such as laser processing, and forming a code. Since this light-shielding layer must be capable of adhering to a rubber-like elastic substrate, a light-shielding pigment typified by carbon black or the like can be attached to the same resin that constitutes the substrate. A resin component (primer, coupling agent, etc.), a curing agent, etc. are mixed. This type of push button switch cover member is incorporated in a push button switch device together with a light emitting source such as an LED and a light guide plate, and performs code illumination by turning on the light emitting source.

Usually, in order to color the code, a light-transmitting colored layer having a color tone different from that of the light-shielding layer is previously provided under the light-shielding layer on the top surface of the key top portion by screen printing or the like. It is often used that the translucent colored layer is exposed by removing a part of it. When the pressing operation is repeated for a long period of time, the code on the top surface of the key top gradually wears out and the visibility is lost.Therefore, the above various push button switch cover members are further subjected to surface treatment such as plasma irradiation and corona discharge. It is also known that a transparent resin layer, such as urethane resin, which is less likely to be worn is coated after the treatment.

As shown in the vertical cross-sectional view of FIG. 11, it is assumed that all of the excellent characteristics of the cover member for a push button switch of various modes which have been conventionally used have been combined in recent years.
A combination of lower two-piece cover members 101 and 102 and a click plate 103 incorporated into a push button switch device 104 has also been used. In this push-button switch device 104, the upper cover member 101 is such that a large convex portion which is a key top portion 106 is provided on a flat sheet 105 which is a rubber-like elastic body. The key top portion 106 itself is formed of a rubber-like elastic body or a high hardness resin. In addition, the lower cover member 10
2 has a small convex portion which is a click plate pressing portion 108 provided on the lower surface of a flat sheet 107 which is a rubber-like elastic body.
The click plate pressing portion 108 is formed of a rubber-like elastic body or high hardness resin. Underside of flat sheet 105 or flat sheet
Reference numeral 109 is formed on any one of these surfaces, with the top surface of 107 being a flat surface having no irregularities. With such a configuration, a plurality of key tops 10 of different sizes can be
Even if 6 is a cover member disposed adjacent to each other, it is possible to form the code 109 of good quality. Therefore, the upper cover member 101 and the lower cover member 102 are formed of a transparent material. In this type, the cover member itself cannot be formed with a thin-walled movable part that acts as a spring,
The push button switch device 104 has a separate click plate 103 made of metal or plastic as described above.

[0007]

A cover member for a push button switch, in which a key top portion is made of high hardness resin, a thin movable portion and a base portion are made of a rubber-like elastic body, provides a good pressing feeling and smooth push button operation. It has the advantage that it can. However, in manufacturing, it is difficult to always keep the boundary position between the high hardness resin portion and the rubber-like elastic body portion constant and there are variations, and there is a disadvantage that they may differ in appearance when compared individually. This is because there is a limit to the accuracy itself of the discharging device that fills the mold with the high hardness resin. Furthermore, the high-hardness resin and the rubber-like elastic body have a unique color tone, and the color tone is different at the boundary position. In addition, it has been technically difficult to make the push button switch cover member a code-illuminated type that has good visibility even in a dark place. In other words, the light-shielding coating layer that can be provided on the rubber-like elastic portion is different from the light-shielding coating layer that can be provided on the high-hardness resin portion (adhesiveness, elastic modulus, heat shrinkage rate, etc.). However, there is a drawback that an accurate masking technique is required and the number of steps must be increased, resulting in high cost.

Further, the conventional code-illumination type push-button switch cover member of the type using a phosphorescent pigment or a self-luminous pigment has a low illuminating ability of the pigment itself, resulting in deterioration of durability due to addition of the pigment, It has not been put on the market so much because it has various problems such as the color being limited to the unique pale yellow-green color.

Further, a transparent resin layer such as urethane resin,
A cover member made of a rubber-like elastic material and provided on at least the top surface of the key top portion is also unsatisfactory in terms of hard finger touch. Furthermore, the two-piece cover member that has been adopted in recent years has the advantage that a push button switch with excellent code quality can be obtained because the code can be formed on a flat surface. However, this type always requires a click plate, and in order to incorporate the click plate into the push button switch device together with the upper cover member and the lower cover member, they must be accurately aligned, and the guide protrusion for positioning is bothered. I had to set it up. Further, there is a drawback that the upper cover member and the lower cover member are locally brought into close contact with each other at the time of pressing, and the close contact portion causes interface reflection due to external light, resulting in poor visibility.

[0010]

The present invention has solved many of the problems described above, and a two-piece cover member for a push button switch according to the present invention has one or more key tops having a recess on the bottom surface thereof. Portion, a thin-walled portion located on the skirt of the key-top portion, and a transparent upper cover member including a base portion that supports the key-top portion through the thin-walled portion, and one or more having a sign on the top surface. Of the convex portion, the thin movable portion located in the skirt of the convex portion, the base portion that supports the convex portion through the thin movable portion, and the contact portion that bulges downward from approximately the center of the bottom surface of the convex portion. The upper cover member is laminated on the lower cover member by fitting the concave portion into the convex portion, and the concave portion of the upper cover member and the convex portion of the lower cover member at this time are horizontal. 0 to + 0.7mm clearance, height Direction of the clearance is 0~ + 0.2mm
And the surface roughness (Ra) of the bottom surface of the recess of the upper cover member is 0.
1 to 0.6 μm, the surface roughness (R
a) is 0.8 to 1.7 μm. In one aspect of the present invention, the top surface of the key top portion of the upper cover member is made of a transparent resin having a Shore D hardness of 40 to 80 degrees. Hereinafter, the present invention will be described in detail with reference to the drawings.

[0011]

1 (a) is a perspective view showing a two-piece cover member for a push button switch of the present invention in which two-piece members of an upper cover member 1 and a lower cover member 2 are laminated, and FIG. FIG. 3 is a vertical cross-sectional view of a push button switch device configured by incorporating both laminated members in a panel. Both the upper cover member 1 and the lower cover member 2 are made of a rubber-like elastic body. In the figure, the upper cover member 1 has a key top portion 3 which is a pressing portion on the upper portion, a recess 4 is provided on the bottom surface thereof, and a thin portion 5 is formed at the position of the skirt of the key top portion 3. Base part through part 5
6 supports the key top part 3. Lower cover member 2
Has a convex portion 7 that fits into the concave portion 4 of the key top portion 3,
A thin movable portion 8 is formed at the position of the skirt of the convex portion 7, and the base portion 9 supports the convex portion 7 via the thin movable portion 8. A reference numeral 10 is formed by a colored layer on the top surface of the convex portion 7 of the lower cover member 2. And the upper cover member
The lower cover member 1 and the lower cover member 2 are laminated on the substrate 11 by fitting the concave portion 4 of the upper cover member 1 and the convex portion 7 of the lower cover member 2 together. These are incorporated into the panel 12 to form a push button switch device.

In operation, the selected key top portion 3
The corresponding lower cover member 2 by pushing from above.
The convex portion 7 is pushed down, and the movable contact portion 13 provided on the bottom portion of the convex portion 7 comes into contact with the fixed contact 14 provided on the substrate 11. When you release your finger, the key top part 3 is the thin part 5, the thin movable part.
Restored to its original position by the repulsive force of 8. Tao, code 10
Is provided on the flat top surface of the convex portion 7 of the lower cover member 2, and it is difficult to form a code on the surface of the cover member for a conventional pushbutton switch, and thus the curved top surface or the top surface, which has been shunned. Even the key top portion whose surface is inclined can be formed without any trouble.

Next, based on FIGS. 2 to 5, the upper cover member 1 and the lower cover member 2 in the stacked state of FIG. 1 will be described in more detail by separating them. FIG. 2 shows the upper cover member 1,
(A) is a perspective view showing the front surface side, and a key top portion 3 projects upward from a flat sheet portion.
(B) is a perspective view showing the back surface side of the upper cover member 1 of (a), and a recess 4 is formed on the back surface of the key top portion 3. Further, on the back surface side, there is provided an exhaust groove 15 for discharging the air between the upper cover member and the lower cover member to the outside when the key top portion 3 is pressed as a push button switch device. The exhaust groove 15 is provided so as to communicate with each recess 4, and at least one exhaust groove 15 reaches the outer end of the upper cover member 1 in order to facilitate exhaust.

FIG. 3 shows the lower cover member 2, and FIG. 3 (a) is a perspective view showing the surface side thereof. The convex portion 7 projects upward from the flat sheet portion, and the top surface of the convex portion 7 is shown. Sign 10
Is provided. (B) is the lower cover member 2 of (a)
FIG. 6 is a perspective view showing the back surface side of the above, in which a concave portion 16 is formed on the rear surface of a convex portion 7 protruding upward, and a movable contact portion 13 is provided substantially at the center thereof. Further, similarly to the upper cover member 1, an exhaust groove 15 for discharging the air between the lower cover member 2 and the substrate 11 (see FIG. 1B) to the outside is provided so as to communicate each recess 16. At least one exhaust groove 15 reaches the outer end of the lower cover member 2 to facilitate exhaust. FIG. 4 shows another embodiment of the upper cover member 1 (a) and the lower cover member 2 (b). Both of them are made of a translucent material, and the surface of the lower cover member 2 has convex portions 7
A light-shielding colored layer is provided on the entire surface except the reference numeral 10 on the top surface.

In the two-piece cover member for a push button switch according to the present invention, since the reference numeral is provided on the convex top surface of the lower cover member,
Conventionally, it is possible to manufacture a cover member in which adjacent key top portions have different heights, which have been shunned because it is difficult to form a code. An example is shown in FIG. (A) is an upper cover member 1 and (b) is a perspective view showing the lower cover member 2. Therefore, the size, shape, and arrangement of the key top portion are not particularly limited as long as the operation of the push button switch is not hindered.

The thickness of the thin portion 5 of the upper cover member 1 is not particularly limited as long as it can slide, but is 0.1 to 0.8 m.
The range of m is preferable, and it may be set thinner than the thickness of the base portion 6. It is to be noted that a preferable pressing feeling can be obtained by forming the thin wall portion 5 into an inverted bowl shape (dome shape) to form a thin wall movable portion having a repulsion function against pressure. Thin part 5
It is preferable that the thickness of the sheet-shaped base portion 6 supporting the plurality of key top portions 3 via the is about 0.4 to 1.5 mm. The lower surface of the sheet-shaped base portion 6 of the upper cover member 1 (the contact surface with the base portion 9 of the lower cover member 2) has a role of discharging the air in the key top portion to the outside during pressing. The exhaust groove 15 may be provided so as to communicate between the key tops and to communicate at least at one location with the outer periphery (outer end in the case of a rectangle). Similarly, the base portion 9 of the lower cover member 2
The exhaust groove 15 may be provided on the lower surface (the contact surface with the upper surface of the substrate 11) of. The exhaust groove 15 has a depth of 0.1 to 0.
It is preferable that the width is 4 mm and the width is 0.5 to 1.6 mm.

Further, the key top portion 3 of the upper cover member 1
There is a slight clearance between the concave part 4 provided on the bottom surface of the cover and the convex part 7 of the lower cover member 2 that fits with this part. Considering the above, a tolerance of 0 to +0.7 mm in the horizontal direction and 0 to +0.2 mm in the vertical direction (that is, the height direction) is permissible within a range that does not affect the pressing operation. By setting the clearance within this range, the upper cover member 1 and the lower cover member 2
And the upper and lower cover members are integrally fitted and held by the rubber adhesiveness of the upper and lower cover members.

Further, the surface roughness (Ra) of the recess 4 of the upper cover member 1 is 0.1 to 0.6 μm, preferably 0.2 to 0.4 μm.
And It is not preferable to adjust the surface roughness (Ra) of the recesses 4 to less than 0.1 μm in terms of processing, and if it exceeds 0.6 μm, the transparency of the key tops 3 is lost and it becomes unclear because it becomes white and turbid. Therefore, the surface roughness (Ra) of the recess 4 is within the above range. The surface roughness (Ra) of the top surface of the key top portion is preferably 0.1 to 0.3 μm, but is not necessarily limited to these ranges.

Reference numeral 10 is provided on the top surface of the convex portion 7 of the lower cover member 2.
Printing surface is formed, but this printing surface does not necessarily have to consist of one layer. Reference numeral 10 may be formed of one transparent or light-shielding colored layer, and the transparent coloring layer and the light-shielding coloring layer are laminated in this order on the top surface of the convex portion 7, and a part of the light-shielding coloring layer is formed. May be removed so that the transparent colored layer is exposed as a code. A colored layer may be provided not only on the top surface of the convex portion 7 but also on the side surface of the convex portion 7, the thin-walled movable portion 8 and the base portion 9. Should be formed. The sign
The colored layer forming 10 has an arbitrary thickness. The top surface of the convex portion 7 is a plane convenient for printing the reference numeral 10. Further, the height of each convex portion 10 is substantially the same. "Substantially the same" means that the height difference of each convex portion is less than 1 mm, which enables excellent quality code formation on all top surfaces of the convex portions even if pad printing is performed, and more preferably a screen capable of forming a clear code. The length should be less than 0.5 mm, which enables code formation with excellent quality even by the printing method.

The shape of the thin movable portion 8 of the lower cover member 2 is an inverted bowl shape, the thickness of which is 0.1 to 0.6 mm, and the base portion 9 thereof.
The thickness is preferably 0.4 to 4.0 mm, but is not necessarily limited to these ranges. A protrusion with a diameter of 1 to 10 mm (at least smaller than the outer diameter of the protrusion 10) bulges downward is present in the approximate center of the bottom surface of the protrusion 10, and the tip of the protrusion has a movable contact portion of a carbon layer or a metal layer. 13 are provided. The thickness of the carbon layer is 10 to 60 μm when it is formed by printing in the subsequent step, and it is 0.2 to 0.5 mm when it is integrally molded with carbon conductive chips. As the metal layer, a nickel plate, a nickel silver plate, or those plated with gold, silver, titanium, or the like is used, and the thickness thereof is 10 to 50 μm when a metal conductive chip is integrally molded.

The surface roughness (Ra) of the code surface of the convex portion 7 is 0.8 to
It is 1.7 μm, preferably 1.1 to 1.5 μm. When the surface roughness of the reference numeral 10 is less than 0.8 μm, only the part to which strong force is applied when pressed is in close contact, and the surrounding area is in a floating state. The unevenness occurs and the visibility of the code 10 is impaired. If the surface roughness (Ra) of the code surface exceeds 1.7 μm, the diffused reflection at the pressed portion will be too strong, and the key top portion 3 itself will appear whitish. It is not necessary to use a transparent raw material for the lower cover member 2, but FIG. 4 (b) and FIG. 5 (b)
In the case of a mode in which a light-shielding layer is provided on the entire surface of the lower cover member 2 except for the reference numeral 10, as shown in FIG.

The upper cover member 1 and the lower cover member 2
Are all made of a rubber-like elastic body. Examples of the rubber-like elastic body include synthetic rubber such as urethane rubber, acrylic rubber, butyl rubber, silicone rubber, isoprene rubber, ethylene-propylene-diene terpolymer (EPDM), natural rubber, polyester-based or urethane-based An example is a plastic elastomer. In addition, precision workability,
It is preferable to select a silicone rubber that is excellent in various physical properties such as electric insulation, impact resilience, heat resistance and cold resistance in a well-balanced manner. Further, with respect to the upper cover member 1, it is most preferable that all of the raw materials constituting the upper cover member 1 are transparent, but at least it must be transparent.

It is preferable that at least the top surface of the key top portion of the upper cover member 1 is made of a resin having a Shore D hardness of 40 to 80 degrees so that the sticky feeling peculiar to rubber at the time of pressing is eliminated and the push button operation becomes good. . At this time, the range of hardness increase of the upper cover member 1 is up to the thin portion 5 and not the portion, and preferably 0.5 mm above the bottom surface of the concave portion 4 of the key top portion 3 which is fitted with the convex portion 7 of the lower cover member 2. Up to Key top part 3 To provide a resin layer with a Shore D hardness of 40 to 80 degrees on the top surface, it is necessary to select a resin that can be firmly bonded to the rubber-like elastic body that forms the other part of the upper cover member. is there. Adhesion of a hard resin chip and a rubber-like elastic body using a primer is complicated because the process is complicated, and a step is likely to occur at the joint part in appearance, and the transparency is likely to be deteriorated. It is preferable to select a resin that can be integrally molded with the elastic body. In this case, the silicone rubber compound is selected to have a vinyl group, and the thermosetting resin is a resin composition prepared by mixing an unsaturated polyester resin or an acrylic resin with a vinyl monomer together with a curing agent, or A high-hardness silicone resin such as diphenyldimethyl silicone resin or phenylmethyl silicone resin may be selected. An epoxy resin or the like may be added to the resin composition in order to eliminate the difference in shrinkage from the silicone rubber portion (rubber-like elastic body portion) or to supplement the strength of the cured resin composition.

Next, a method of manufacturing the two-piece cover member for a push button switch of the present invention will be described. The method of manufacturing the cover member for a push button switch in the mode in which both the upper cover member and the lower cover member are formed of a rubber elastic body may be performed in the same manner as in the case of a general silicone rubber molded product, and specifically, A molding method such as compression molding, injection molding or injection compression molding may be used. In the case of a mode in which a thermosetting resin layer having a Shore D hardness of 40 to 80 degrees is provided on the top surface of the key top portion of the upper cover member, two separable molds are used,
A predetermined amount of liquid thermosetting resin composition that can be integrally molded with uncured rubber is filled into the engraved portion for forming the key top portion of the mold, and after curing for a time that does not cause loss of adhesive performance, further on top of it Injection molding method of filling an uncured rubber-like elastic body, or compression molding method of pressurizing from above the filled uncured rubber-like elastic body, and the resin composition and rubber-like elasticity previously filled The body and the body may be integrally cured and taken out from the mold.

The recess of the bottom surface of the key top portion of the upper cover member is preferably adjusted to have a surface roughness (Ra) of 0.1 to 0.6 μm by using, for example, a method such as ultraviolet irradiation.
The conditions for UV irradiation are the size of the workpiece, the thickness of the thin wall,
The irradiance is less than 200 mW / cm ² , and the cumulative light intensity is 200 to 15000 mJ, although there are some differences depending on the grade of the raw material.
The range is / cm ² (determined by the distance from the ultraviolet radiation lamp to the work (irradiation distance) and irradiation time). The wavelength of UV irradiation is generally 184.9 nm
And two wavelengths of 253.7 nm can be irradiated simultaneously.

It is preferable to form the code on the top surface of the convex portion of the lower cover member by a printing method, and specific examples thereof include a screen printing method and a pad printing method. The ink to be used may be a resin component of a rubber-like elastic body that constitutes the base material of the lower cover member, with a predetermined amount of an organic or inorganic coloring agent and a curing agent, a catalyst or the like. Since the code surface of the top surface of the convex portion must have a surface roughness (Ra) of 0.8 to 1.7 μm, it is surface-modified by the ultraviolet irradiation treatment like the upper cover member. In this case, the conditions for UV irradiation are irradiance of less than 200 mW / cm ² and integrated light intensity of 18000.
The range may be up to 35000 mJ / cm ² . The most preferable method for adjusting the surface roughness (Ra) of the code surface of the convex top surface to 0.8 to 1.7 μm is to use silica powder having a particle size of 0.8 to 65 μm.
At least one layer of solid printing (printing on the entire top surface) is performed on the top surface of the convex portion by screen printing using an ink mixed with 5 to 40 parts by weight, and then an ink of different coloring (similarly to a particle size of 0.8 5 to 40 parts by weight of silica powder having a particle size of ˜65 μm is added). When a code surface with a predetermined surface roughness is formed by ultraviolet irradiation treatment, there is the disadvantage that the code surface is slightly deteriorated and the color tone changes, but solid printing is performed with an ink containing a silica powder of a predetermined particle size. It is more preferable that the symbols and are provided because such inconvenience does not occur.

It is preferable that the upper cover member has a concave portion that fits with all the convex portions of the lower cover member.
In a push button that is used less frequently, as shown in the vertical cross-sectional view of FIG. 6, there may be a portion in which a part of the convex portion of the lower cover member is not covered with the upper cover member. Further, the lower cover member may be produced in large quantity as a common component, and may be used in combination with an upper cover member having a key top portion having the same arrangement of the convex portions and the arrangement of the concave portions but different shapes. For example, although the shape of the key top portion of the upper cover member is different between FIG. 4 and FIG. 5, it is shown that the common lower cover member 2 may be used.

The mechanism by which uniform visibility is obtained by the two-piece cover member for a push button switch of the present invention will be described in detail with reference to FIGS. 7 to 10. FIG. 7A particularly shows the surface of the concave portion 4 on the bottom surface of the key top portion 3 and the lower cover member 2.
10 is a longitudinal sectional view showing a state in which the upper and lower cover members 1 and 2 are molded without adjusting the surface roughness of reference numeral 10 and the top surface of the key top portion 3 of the assembled push button switch is pressed with a finger. . At this time, as shown by reference numeral 10, as shown in FIG. 7 (b), the portion where the force is applied becomes clear, and the other portions become indistinct. The bad state will continue for a predetermined time. It is considered that this is because the surface roughness varies due to the influence of the flow of the raw material during the molding process of the upper and lower cover members, and due to the adhesiveness peculiar to the rubber elastic body, the portions to which force is applied adhere to each other. If this state is compared, it is similar to that a water drop is interposed between two glass plates, and when viewed from one side, the part where the water drop is present has a different refractive index from the other parts, which is similar to the feeling of strangeness.

On the other hand, FIG. 8 (a) is a vertical section showing a state in which the top surface of the key top portion 3 of a push button switch assembled using the two-piece cover member for a push button switch of the present invention is pressed with a finger. It is a side view. Further, a part thereof is enlarged and shown in FIG. The surface treated surface 20 of the concave portion 4 on the bottom surface of the key top portion 3 and the surface treated surface 21 of the convex portion 7 of the lower cover member 2 are
Although it abuts when pressed from above, as seen in FIG. 8B, since the abutting surfaces are rough surfaces, they do not come into close contact with each other and are excellent in visibility. Since the concave portion 4 of the upper cover member 1 was prepared by irradiating the surface roughness (Ra) of 0.1 to 0.6 μm with ultraviolet rays, the adhesiveness peculiar to the rubber-like elastic body was lost, and the convex portion 7 of the lower cover member 2 was lost. Reference numeral 10 on the top surface has a relatively rough surface roughness (Ra) of 0.8 to 1.7 by ultraviolet irradiation or by printing with an ink containing a predetermined amount of silica powder having a predetermined particle diameter. By making it μm, the surface hardness of the code part is increased by 3 to 5 degrees, and a uniform light diffusion effect is brought about, and when pressing, locally sharp and unclear parts are mixed. And uniform visibility is ensured.

The method of assembling the two-piece member for a push button switch of the present invention into the push button switch device is the same as the conventional cover member for a push button switch.
The upper cover member 1 may be laminated in this order and incorporated. If positioning is required, provide guide pins at any location on the substrate 11 and also cover the upper cover member 1 and the lower cover member 2
It suffices to provide guide holes at the same position on both. If a sign-illuminated push button switch device is desired, as shown in Fig. 10, the panel 12 and the sheet-shaped base portion 6 of the upper cover member 1 are used.
The light emitting source 17 may be installed so as to be located between the above and the light emitting source 17, or the light emitting source 17 may be provided below the lower cover member 2.

The two-piece cover member for a push button switch of the present invention can be easily assembled by fitting the concave portion of the upper cover member and the convex portion of the lower cover member. By making the convex top surface of the lower cover member a flat surface, the code can be printed extremely easily by the screen printing method,
The code quality and visibility are also good. Since the lower cover member is protected by the transparent upper cover member, the visibility of the code is not lost semipermanently even if it is used for a long period of time. Further, by providing the exhaust grooves on the back surfaces of the base portion of the upper cover member and the base portion of the lower cover member, the pressing operation can be performed smoothly. The surface roughness (Ra) of the recess of the upper cover member is 0.1-
0.6 μm, and the surface roughness (Ra) of the top surface code surface of the convex portion of the lower cover member is 0.8 to 1.7 μm, so even if pressed, local adhesion does not occur on the key top part, and therefore uniform visibility Is secured. Furthermore, the horizontal clearance between the concave portion of the upper cover member and the convex portion of the lower cover member should be 0 to +
With 0.7mm and height clearance of 0 to + 0.2mm, it is easy to assemble the upper cover member and the lower cover member, does not affect the pressing operation, and allows for local adhesion and local reflection. It does not occur and good visibility is obtained. Less than,
Embodiments of the present invention will be described in detail based on examples.

[0032]

EXAMPLES Prior to the examples, the relationship between the surface roughness of the concave portion on the bottom surface of the key top portion of the upper cover member and the surface roughness of the code surface formed on the convex portion of the lower cover member and the visibility was examined. [Preliminary test 1] Silicone rubber compound KE-951U
(Shin-Etsu Chemical Co., Ltd., trade name) 100 parts by weight and hardener C-8
(Shin-Etsu Chemical Co., Ltd., trade name) 2 parts by weight are mixed, kneaded and compression-molded at a temperature of 200 ° C. and a pressure of 200 kg / cm ² for 2 minutes, and a silicone rubber plate A with dimensions of 2 mm × 20 mm × 20 mm I got multiple cards. Next, the liquid of methylphenyl silicone resin was filled into a mold having a mirror-finished surface heated to 180 ° C using an air dispenser AD3000 (manufactured by Iwashita Engineering Co., Ltd.), and the fluidity disappeared. By the way, 100 parts by weight of transparent grade silicone rubber compound DY32-379U (product of Toray, trade name) was filled with 0.5 parts by weight of RC-8 curing agent, the silicone rubber raw material was filled, the mold was closed, and the temperature was 180 ° C. , At a pressure of 200 kg / cm ² 2
After compression molding for a minute, a plurality of plates B were obtained in which a methylphenyl silicone resin layer having a size of 1 mm × 20 mm × 20 mm and a silicone rubber layer having the same size were laminated. The thickness of the coating layer is 30 μm by screen printing with silicone resin black ink on one side of the silicone rubber plate A.
Formed a triangular mark. Prepare the ones prepared by changing the surface roughness of the triangular mark forming surface of plate A and the silicone rubber surface of plate B by UV irradiation, and stacking these plates A and B in various combinations (however, Laminate so that the triangular mark forming surface of A touches the silicone rubber surface of plate B), plate
The visibility of the code was confirmed by pressing with a finger from the high hardness resin surface side of B. Table 1 shows the results. The “untreated” display in the table indicates that the ultraviolet irradiation treatment was not performed.

[0033]

[Table 1]

From the above results, the plate B on the pressing side
The lower surface of has a surface roughness (Ra) of 0.1 to 0.6 μm,
It was found that uniform and excellent visibility was obtained when the surface roughness (Ra) of the code forming surface of the plate A on the code formed side was 0.8 to 1.7 μm.

[Example 1] Silicone rubber compound KE-951U (manufactured by Shin-Etsu Chemical Co., Ltd., trade name) 100 parts by weight and curing agent C-8 (Shin-Etsu Chemical Co., Ltd., trade name) 2 parts by weight of silicone rubber Kneading raw materials, temperature 185 ℃, pressure 200k
Compression molding was performed at g / cm ² for 2 minutes to obtain a substrate for the lower cover member. The thickness of the convex surface of this board is 7 by screen printing.
A transparent colored layer of μm is formed, and a thickness of 15
A μm light-shielding colored layer was removed and laminated in a code shape to form a code necessary for telephone operation. In addition, 20 particles of silica particles having a particle size of approximately 30 μm were added to the ink used for forming the light-shielding colored layer.
The surface roughness (Ra) of the convex top surface was set to 1.1 μm. Further, a movable contact portion was printed by using carbon conductive ink to obtain a lower cover member. Next, silicone rubber compound, DY32-379U (made by Toray, trade name)
Prepare a silicone rubber raw material consisting of 100 parts by weight and 0.5 part by weight of a curing agent, RC-8 (trade name, manufactured by Toray) and molding temperature 185
° C., to obtain a substrate for the upper cover member molding pressure 200 kg / cm ^2, compression molded to the condition that the molding time of 2 minutes 45 seconds. UV-DRY-PROCESSOR ・ VUM is placed in the recess on the bottom of the key top of this board.
-3333-A (Oak Seisakusho Co., Ltd., product name) was used for UV irradiation at an irradiation distance of 15 cm for 2 minutes.
An upper cover member having a concave surface roughness (Ra) of 0.3 μm was obtained.

The heights of the key tops of the upper cover member are individually different and have a maximum and a minimum of 5 mm, and the top surface of the key top has a convex shape with a radius of curvature of 5 mm. . The upper cover member was laminated on the lower cover member and incorporated into a telephone case together with a plurality of LEDs to assemble a telephone push button switch device. In this device, when the key top is pressed, the LED lights up and the code is illuminated. When the push button operability and the code visibility of this device were confirmed, the pressing operation had a good click feeling and the code was clearly visible. In the case of a conventional push button switch cover member, the height between adjacent key tops is 3.
If the difference is 5 mm or more, it is difficult to form the code, but the code of the cover member for the push button switch obtained in this embodiment is formed with high quality.

[Embodiment 2] The lower cover member used in Embodiment 1 is used, and the upper cover member is formed of a thermosetting resin up to 2.5 mm below the top surface of the key top portion. The member was manufactured by the following method. . Unsaturated polyester resin Ester 1510C (manufactured by Mitsui Toatsu Chemicals, Inc.) 100 parts by weight, diallyl phthalate 35 parts by weight, epoxy resin Epior P on the engraved part for forming the key top part of the mold which has been heated to 160 ° C in advance. -400 (Made by NOF Corporation, product name) 20 parts by weight, melamine resin / Cymel 701 (Mitsui Cyanamid, product name) 15 parts by weight, hardener / niper
1 part by weight of BMT-k40 (made by NOF CORPORATION, product name) and acidic catalyst / catalyst 4050 (made by Mitsui Cyanamid, product name)
An uncured resin composition containing 1 part by weight is filled in a predetermined amount using an air dispenser AD3000, and when the resin composition loses fluidity, a thin portion and a base portion are formed from above. Fill the engraved part with silicone rubber compound DY32-379U (Toray, trade name) 100 parts by weight of curing agent RC-8 (Toray, trade name) 0.5 parts by weight, and fill with silicone rubber raw material. 165 ℃, pressure 200kg /
Integral molding was carried out at a cm ² for 2 minutes to obtain a base material for an upper cover member.

On the concave side of the bottom surface of the key top portion of this base material,
Ultraviolet treatment was performed with an irradiance of 200 mW / cm ² and an integrated light amount of 8000 mJ / cm ² to obtain an upper cover member having a surface roughness (Ra) of 0.4 μm. Although the key tops of the upper cover member have the same height, a plurality of small protrusions indicating the operation content of the push button switch operation in Braille are provided on the top surface thereof. Similar to the first embodiment, the upper cover member is laminated on the lower cover member and incorporated into a telephone case together with a plurality of LEDs, and a telephone push button switch device is assembled (the LED lights up by pressing the key top portion). And the sign is illuminated).
After confirming the push button operability and the visibility of the code of this device, the push operation has a good click feeling, and the push button switch operation can be performed smoothly without the sticky feeling on the top surface of the key top part, and the code is clear. I could see it.

In the conventional push-button switch cover member having the high-hardness resin portion provided on the top surface of the key top portion, a color tone difference was noticeable at the joint between the high-hardness resin portion and the silicone rubber portion. The two-piece cover member for the switch is
High hardness resin and transparent silicone rubber could be used, and the difference in color tone at the boundary was not noticeable. For the conventional push button switch cover member with a high hardness resin key top part, two types of coloring ink for the high hardness resin part and coloring ink for the silicone rubber part are prepared in order to make it a code illuminated type. Although the masking work had to be performed with caution, the thing of the present invention does not require the painting work and the laser processing work as well as the masking work, so that the yield rate is high and the productivity is excellent. Moreover, in the conventional cover member for a push button switch, if there is a protrusion on the top surface of the key top portion, it was difficult to form the code while maintaining the quality, but in the present invention, the code was formed with good quality.

[0040]

The two-piece cover member for a push button switch according to the present invention has a variation in the height of the key top portion of the upper cover member, and an uneven or curved surface on the top surface of the key top portion. A high-quality code can be formed, the pressing operation is excellent, and even when the pressing operation is performed, the code can be displayed with a uniform contrast and excellent visibility, and no discomfort occurs. Further, it is possible to provide a product having an excellent click feeling without using a click plate. Further, even if the key top portion is made of high hardness resin, the code illumination function can be easily provided by using the two-piece cover member for a push button switch having the configuration of the present invention.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a two-piece cover member for a push button switch of the present invention, (a) is a perspective view thereof, and (b) is a perspective view thereof.
FIG. 4 is a vertical sectional view of a push button switch device in which a two-piece cover member for a push button switch of the present invention is incorporated in a panel.

FIG. 2 is a perspective view showing an aspect of an upper cover member constituting a two-piece cover member for a push button switch of the present invention, (a) showing a front surface thereof and (b) showing a rear surface thereof.

FIG. 3 is a perspective view showing one embodiment of a lower cover member that constitutes the two-piece cover member for a push button switch of the present invention, (a) showing the front surface and (b) showing the back surface thereof.

FIG. 4 shows another embodiment of the two-piece cover member for a push button switch of the present invention, (a) shows the upper cover member,
(B) is a perspective view showing a lower cover member.

FIG. 5 shows another embodiment of the two-piece cover member for a push button switch of the present invention, (a) shows the upper cover member,
(B) is a perspective view showing a lower cover member.

FIG. 6 is a vertical cross-sectional view showing another embodiment of the two-piece cover member for a push button switch of the present invention.

FIG. 7 shows a two-piece cover member for a push button switch whose surface roughness is not adjusted, which is used in the present invention, in which (a) is a longitudinal sectional view when it is pressed and (b) is a plan view showing its visibility. is there.

FIG. 8 shows a two-piece cover member for a push button switch of the present invention, (a) is a vertical cross-sectional view when pressed, and (b) is a plan view showing visibility.

FIG. 9 is a partially enlarged sectional view of a two-piece cover member for a push button switch of the present invention.

FIG. 10 is a vertical cross-sectional view showing another embodiment in which the two-piece cover member for a push button switch of the present invention is incorporated in a push button switch device.

FIG. 11 is a vertical cross-sectional view showing a conventional two-piece cover member for a push button switch.

[Explanation of symbols]

1. ・ ・ ・ ・ Upper cover member, 2. ・ ・ ・ ・ Lower cover member, 3. ・ ・ ・ ・ Key top part, 4. ・ ・ ・ ・ Recessed part,
5 .... ・ Thin part, 6. ・ ・ ・ ・ Base part,
7. ・ ・ ・ ・ Convex part, 8. ・ ・ ・ ・ Thin wall moving part, 9. ・ ・ ・ ・ Base part, 10. ・ ・ ・ ・ Code,
11. ・ ・ ・ ・ Substrate, 12. ・ ・ ・ ・ Panel, 1
3. ・ ・ ・ ・ Movable contact part, 14. ・ ・ ・ ・ Fixed contact,
15 .... Exhaust groove, 16 .... Recess, 17.
.... Light-emitting source, 18 ....- Light-shielding layer, 19.-
... Colored layer, 20 ... Surface-treated surface, 2
1. ・ ・ ・ ・ Surface treatment surface, 101. ・ ・ ・ ・ Upper cover member, 102. ・ ・ ・ ・ Lower cover member, 103. ・ ・ ・ ・ Click plate, 104. ・ ・ ・ ・ Push button switch device, 105 .....
Flat sheet, 106 .... Key top part, 107.
.... Flat sheet, 108 ..... Click plate pressing part,
109 ..... Code, 110 ..... Light source, 11
1. ・ ・ ・ ・ Movable contact part, 112. ・ ・ ・ ・ Fixed contact,
113 .... Panel, 114 .... Substrate.

Claims (2)

[Claims] 1. A key top portion having a recess on its bottom surface, a thin portion located in a skirt of the key top portion, and a base portion supporting the key top portion through the thin portion. A transparent upper cover member, one or more convex portions having a symbol on the top surface, a thin movable portion located in a skirt of the convex portion, and a base portion that supports the convex portion via the thin movable portion. A lower cover member consisting of a contact portion that bulges downward from substantially the center of the bottom surface of the convex portion, wherein the upper cover member is laminated on the lower cover member such that the concave portion is fitted to the convex portion. When the horizontal clearance between the concave part of the upper cover member and the convex part of the lower cover member is 0 to +0.7 mm,
The clearance in the height direction is 0 to +0.2 mm, the surface roughness (Ra) of the bottom surface of the recess of the upper cover member is 0.1 to 0.6 μm,
The surface roughness (Ra) of the convex top surface of the lower cover member is 0.8 to 1.7.
Two-piece cover member for push-button switches, which is characterized by being μm. 2. The two-piece cover member for a push button switch according to claim 1, wherein the top surface of the key top portion of the upper cover member is made of a transparent resin having a Shore D hardness of 40 to 80 degrees.