JPH07288061A - Manufacture of embossed sheet for membrane switch and mold for manufacturing embossed sheet - Google Patents

Abstract

PURPOSE:To provide an efficient manufacturing method and better switching property as a result of stable emboss property by holding a resin sheet between the protrusion and the recess of a die and cooling it right after heating and molding. CONSTITUTION:A PET sheet 23 placed on the upper face of a middle plate 37 is arranged between a male mold 21 and a female mold 22, the mold 22 is moved upward and both molds 21, 22 are clamped to hold the sheet 23. In this way, a protruded portion is formed on the sheet 23 in a shape corresponding to the protrusion 33. Then, a heater 36 is switched on, the protrusion 33 is heated at a thermally deforming point of the sheet 23 or higher and the protruded portion formed on the sheet 23 is kept under high temperature heat. After heating for a certain time, the heater is switched off to release the protrusion 33 from heat and cooling air is guided into a space 26 in the mold 21 through a pipe 30 to cool the protruded portion formed on the sheet 23. Then, the mold 22 is moved downward to separate the 22 from the mold 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die and a method for producing a membrane switch suitable for use in a keyboard switch of electronic equipment.

[0002]

2. Description of the Related Art Membrane switches are known as thin switch input devices for electronic equipment. Figure 4
It is a figure which shows the structure of the membrane switch provided with the general click board. Reference numerals 1a and 1b are electrode supporting sheets, and the electrode supporting sheets 1a and 1b are aligned so that the electrodes 2a and 2b on a circuit pattern installed on the surface thereof are planarly aligned with each other, Spacer 3
Are installed facing each other via. Further, metal click plates 4 are arranged above the upper electrode support sheet 1a where the electrodes 2a and 2b are present. The click plate 4 is provided to give the operator a feeling of pressing the switch (click feeling) when the membrane switch 5 is pressed, and is adhered to the electrode supporting sheet 1a through the spacer 3. It is adapted to be fixed at a predetermined position by the pressing sheet 6.

However, the membrane switch 5 having the above-mentioned structure has drawbacks such that the manufacture of the click plate 4 itself and the assembly work of the switch accompanied by the alignment of the click plate 4 are complicated. Therefore, as an improvement measure, the following membrane switch was devised. FIG. 3 is a diagram showing an improved membrane switch. The membrane switch 7 is different from the membrane switch 5 only in the configuration on the upper electrode side.
Instead of using, the upper electrode supporting sheet 9a made of elastic polyethylene terephthalate resin, to which the upper electrode 8a is attached, is curved at the electrode installation portion to form a dome-shaped convex portion 10a.
Is processed so that the click plate 4 serves as the click plate 4. (Hereinafter, processing a flat sheet so as to form a dome-shaped convex portion is referred to as embossing, and a sheet subjected to embossing is referred to as an embossing sheet.) Then, the upper electrode sheet 9
A cover sheet 11 is installed on the upper part of a.

In this membrane switch 7, when the convex portion 10 of the upper electrode sheet 9a having elasticity is pushed, the upper electrode sheet 9a bends and the upper and lower electrodes 8a and 8b come into contact with each other, so that the contact is conducted. Since the upper electrode sheet 9a has elasticity when the finger is released, the upper electrode sheet 9a is restored and the upper and lower electrodes 8a and 8b are separated from each other, so that the contact is interrupted and the switch operation is performed. The membrane switch 7 has an advantage that constituent members such as the click plate 4 can be omitted and the switch operation is stable.

By the way, as a conventional method for embossing the upper electrode sheet 9a, a method using both a hot press machine and a cold press machine is known. That is, the sheet made of the polyethylene terephthalate resin (hereinafter,
It is called PET sheet. ) Is clamped and the mold is heated to a temperature of 10
The PET sheet is deformed by applying pressure for 2 minutes on a hot press machine set at 0 ° C. Next, the mold is
Transfer to a cold press machine set at ° C and pressurize for 2 minutes. After that, even if the PET sheet is removed from the mold, the shape of the convex portion 10 of the PET sheet is maintained as it is, and the embossed sheet is completed.

[0006]

However, in the method in which the hot press machine and the cold press machine are used together, two press machines are required, so that the burden of equipment cost is large and each press machine has its own burden. Since it takes time to heat or cool the mold, there is a problem that the manufacturing efficiency is poor.

As another method, there is a method of embossing by mechanical deformation using only a cold press machine. In this method, embossing characteristics (dome shape during molding of an embossed sheet, mainly, The emboss height is liable to change, and there is a problem that switching characteristics, which are the load values (maximum load, minimum load, ON load) of the switch, tend to vary.

The present invention has been made in view of the above circumstances, and has a small load on the press equipment, a high manufacturing efficiency, and a stable switching of the embossing characteristics to obtain good switching characteristics. An object of the present invention is to provide a method for manufacturing an embossed sheet for a switch and a mold for manufacturing the embossed sheet.

[0009]

A method of manufacturing an embossed sheet for a membrane switch according to claim 1, wherein the embossed sheet is arranged above a pair of electrodes arranged facing each other and spaced apart from each other, and the embossed sheet has a convex shape. A method for manufacturing the embossed sheet for a membrane switch that operates a part to open and close the electrode, wherein the embossed sheet comprises:
A step of sandwiching a resin sheet between one die having a convex portion and the other die having a space at a position facing the convex portion, and the convex portion of the one die for a predetermined time. A step of heating the convex portion formed on the resin sheet at a high temperature, and introducing the cooling air into the space of the other mold after releasing the heating of the convex portion to form the resin sheet. It is manufactured by a process of cooling the convex portion of.

The mold for manufacturing an embossed sheet according to claim 2 is the mold for manufacturing an embossed sheet used in the method for manufacturing an embossed sheet for a membrane switch according to claim 1, wherein a convex portion is formed on the first processed surface. One of the formed dies, the other of the dies on which the second processing surface facing the first processing surface is provided with a space portion opening at a position corresponding to the convex portion, It is characterized by comprising heating means for heating the convex portion of the mold and air introducing means for introducing cooling air into the space of the other mold. Here, as the heating means, an electric heating device such as a heating coil or a heater can be considered, and an instantaneous on / off type electric heating device capable of heating immediately is suitable. Further, as the air introducing means, for example, a pipe line that introduces cooling air from an air supply source and is arranged in the space of the other mold is conceivable.

The mold for manufacturing an embossed sheet according to a third aspect is the mold for manufacturing an embossed sheet according to the second aspect, wherein the opening end of the space portion is formed on the second processed surface of the other mold. A wall surface that is closed and has heat-resistant rubber adhered thereto and that forms the space of the other mold has a tapered surface in the vicinity of the opening end that gradually increases in diameter from the inside toward the opening end. It has a feature.

[0012]

In the method for manufacturing an embossed sheet for a membrane switch according to claim 1, first, between one die having a convex portion and the other die having a space at a position facing the convex portion. Hold the resin sheet. As a result, a convex portion having a shape corresponding to the convex portion of the one mold is formed on the resin sheet. Next, the convex portion of one mold is heated for a certain period of time to keep the convex portion formed on the resin sheet at a high temperature. In this case, the resin sheet is plastically deformed by heat to form the convex portion. Then, after the heating of the convex portion is released, cooling air is introduced into the space of the other mold to immediately cool the convex portion of the resin sheet. After that, when the two molds are released from each other, the embossed sheet on which desired convex portions are formed is completed.

In the die for producing an embossed sheet according to claim 2, when the resin sheet is placed between one die and the other die and the die is clamped, the one die is attached to the resin sheet. A convex portion having a shape corresponding to the convex portion of the mold is formed. After that, when the convex portion of the one mold is heated by the heating means to place the convex portion formed on the resin sheet at a high temperature, the resin sheet is plastically deformed by heat. Then, cooling air is introduced into the space of the other mold to cool the convex portion formed on the resin sheet, and then the two molds are released from each other to form a desired convex portion. The embossed sheet is completed.

In the die for producing an embossed sheet according to claim 3, when the resin sheet is placed between the one die and the other die and the die is clamped, the die of the other die is The heat-resistant rubber adhered to the processed surface of 2 by closing the opening end of the space portion presses the surface of the resin sheet opposite to the convex portion of the one mold, and the convex portion of the resin sheet is formed. The part surface is made to fit into the convex part of the one mold. Further, in this case, the taper surface of the wall surface forming the space of the other mold gives an appropriate stress to the rising portion of the convex portion formed on the resin sheet to clarify the shape of the rising portion. Let

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. This embodiment relates to a method for manufacturing the embossed sheet (upper electrode sheet 9a) for the membrane switch 7 described in FIG. 3 and a mold for manufacturing the embossed sheet. FIG. 1 is a diagram showing a mold for manufacturing an embossed sheet according to this embodiment. In this figure, reference numeral 21 is an upper die (the other die), 22 is a lower die (one die), and 23 is a PET sheet (resin sheet).

The upper die 21 is composed of an upper die 24 and an upper die mounting portion 25 to which the upper die 24 is attached. In the upper mold 24, the space 2 that opens to the second processing surface 27 at the lower end
6 is formed. The shape of the space 26 is circular in horizontal cross section. The wall surface forming the space portion 26 of the upper mold 24 is a tapered surface 28 in the vicinity of the opening end 26a whose diameter gradually increases from the inside toward the opening end 26a.

Further, the upper die mounting portion 25 is formed with a through hole 29 communicating with the space portion 26 of the upper die 24. Inside this through hole 29, a pipe line 30 (air introducing means) for introducing cooling air from an air supply source (not shown) is arranged inside the space 26. A heat resistant rubber 31 is attached to the second processed surface 27 of the upper mold 24 so as to close the opening end 26a of the space 26. The heat resistant rubber 31 is made of silicon and has a thickness of 1.5 mm.

On the other hand, the lower mold 22 is fitted in the lower mold 32 and the hole formed in the lower mold 32, and the upper end portion thereof is the convex portion 3.
3 and a lower mold attaching portion 35 to which the lower mold 32 and the convex mold 34 are attached. A heater 36 (heating means) is built in the convex portion 34, and electric power is supplied from the outside and is turned on and off to heat and release the electric power. There is. In this case, as the heater 36, an electric heating device of a type (for example, a heat coil) capable of instantaneously heating and releasing is used. The upper surfaces of the lower mold 32 and the convex mold 34 are the first processed surface 39 that constitutes the present invention.

The convex portion 33 is located at a position corresponding to the space portion 26 of the upper die 24, and a position such that the convex portion 33 can relatively enter into the space portion 26 when the two 33, 26 are brought close to each other. Has become. On the other hand, an intermediate plate 37 is arranged between the two molds 21 and 22.
A through hole 38 is formed at a position corresponding to the convex portion 33 and the space portion 26 of 7. The diameter of the through hole 38 is
The size is formed so that the convex portion 33 can be inserted therethrough.

Next, a method of manufacturing the embossed sheet will be described. First, as shown in FIG. 1A, the upper mold 2
1 and the lower mold 22, the PET sheet 23 placed on the upper surface of the intermediate plate 37 is disposed, and the lower mold 22 is moved upward (toward the upper mold 21), so that both molds 21,
The mold 22 is clamped, and the PET sheet 23 is sandwiched via the intermediate plate 37 (see FIG. 2B). This gives P
A convex portion having a shape corresponding to the convex portion 33 is formed on the ET sheet 23.

Next, the heater 36 is turned on to heat the convex portion 33 of the lower mold 22 to a temperature higher than the thermal deformation temperature of the PET sheet 23, so that the convex portion formed on the PET sheet 23 is heated to a high temperature. deep. Then, after heating for a certain period of time, the switch of the heater 36 is turned off to release the heating of the convex portion 33, and then cooling air is supplied from the air supply source (not shown) into the space portion 26 of the upper mold 21 through the conduit 30. Introduced, P
The convex portion formed on the ET sheet 23 is cooled. afterwards,
The lower mold 22 is moved downward to move from the upper mold 21 to the lower mold 2.
Release 2 from the mold. As a result, the embossed sheet (PET sheet 23) having the desired convex portion is completed.

In this embodiment, since the heat resistant rubber 31 is attached to the second processed surface 27 of the upper die 21, the PET sheet 23 is placed between the upper die 21 and the lower die 22. When the two dies 21 and 22 are arranged and clamped, the upper surface of the PET sheet 23 is pressed by the lower surface of the heat resistant rubber 31.
As a result, the PET sheet 23 becomes the convex portion 3 of the lower mold 22.
The shape of the PET sheet 23 is well adapted to the shape of No. 3, and the PET sheet 23 is easily formed into a desired shape (the shape of the convex portion 33).

In this case, wrinkles may occur on the surface of the PET sheet 23 depending on the diameter and height of the convex portion 33, but in this embodiment, the entire upper surface of the PET sheet 23 is covered with the lower surface of the heat resistant rubber 31. Since it is pressed, wrinkles do not occur on the surface of the PET sheet 23 regardless of the diameter and height of the convex portion 33.

Further, in the present embodiment, the wall surface forming the space portion 26 of the upper die 21 is a tapered surface 28 in the vicinity of the opening end 26a, the diameter of which gradually increases from the inside toward the opening end 26a. This is because the embossing characteristic of the embossed sheet is that when the embossed convex portion (reference numeral 10 in FIG. 3) is pushed with a finger to reverse the embossed convex portion, the rising portion of the embossed convex portion (the same 40). This is because it is greatly affected by the shape of. That is, in this embodiment, since the wall surface forming the space 26 is the tapered surface 28, the rising portion 40 of the convex portion formed on the PET sheet 23 when the molds 21 and 22 are clamped.
The mechanical stress can be easily concentrated on, and this part is formed into a desired shape (shape of the convex portion 33).

Further, in this embodiment, since the lower die 22 is provided with the heater 36, the PET sheet 23 can be more easily deformed by heating the PET sheet 23 to a temperature higher than the heat deformation temperature. As a result, it is possible to form a desired shape (shape of the convex portion 33), the embossing characteristics are stabilized, and good switching characteristics can be obtained. Accordingly, it is possible to overcome the drawback that the embossing characteristic is not stable when only the cold press machine is used in the conventional example.

Further, in this embodiment, since only the convex portion 33 (the convex portion formed on the PET sheet 23) can be locally heated by the heater 36, the whole die in the above-mentioned conventional example is hot-pressed. The heating can be performed in a shorter time than the case where the heating is performed at 1, and the manufacturing efficiency can be improved. Further, in this case, because of local heating, residual heat does not remain in the molds 21 and 22 after the heating is released, and it is possible to immediately shift to the cooling step after turning off the switch of the heater 36, The manufacturing cycle can be accelerated.

Further, in this embodiment, one die 21, 2 is used.
2 includes both the heater 36 and the pipe 30 for introducing the cooling air, the load on the facility cost is lower than that in the case where the hot press machine and the cold press machine are used together in the conventional example. The effect of being small can be obtained.

Further, in the present embodiment, like the heater 36, the duct 30 introduces cooling air into the space 26 of the upper mold 21 to form only the convex portion formed on the PET sheet 23. Is locally cooled and the entire die is not cooled by the cold press machine as in the conventional example, so that the time required for cooling can be reduced and the manufacturing efficiency can be improved.

In this embodiment, the heat resistant rubber 31 closes the opening end 26a of the space 26 and is attached to the second processed surface 27 of the upper mold 21, and the pipe line 30 is provided during the cooling process.
The cooling air introduced through the space 26 indirectly cools the PET sheet 23 through the heat resistant rubber 31, but if it is necessary to improve the cooling efficiency as compared with this embodiment, Alternatively, a large number of small holes may be formed in the thickness direction of the heat resistant rubber 31 and the PET sheet 23 may be directly cooled by the cooling air passing through the small holes.

Further, in this embodiment, cooling air is introduced into the space 26 of the upper mold 21 through the pipe 30, and the air discharged toward the heat resistant rubber 31 passes through the space 26. After that, it rises and is exhausted to the outside from the opening of the through hole 29. For example, when it is necessary to introduce cooling air into the space 26 from the entire opening of the through hole 29, as shown in FIG. Are provided on the second processed surface 27 of the upper die 24 in the radial direction from the space portion 26, and the grooves 41, 41.
It may be configured such that the air is exhausted from the outside.

[0031]

According to the method of manufacturing an embossed sheet for a membrane switch of the first aspect, the embossed sheet has one mold having a convex portion and the other having a space portion at a position facing the convex portion. Sandwiching a resin sheet between the resin sheet and the mold, heating the convex portion of the one mold for a certain period of time to keep the convex portion formed on the resin sheet at a high temperature, Since it is manufactured by a step of cooling the convex portion of the resin sheet by introducing cooling air into the space of the other mold after releasing the heating of the part, the conventional example Compared to the method using both a hot press machine and a cold press machine, only one press machine is required and the burden of equipment cost is small, and unlike the conventional method, the entire die is not heated or cooled, and the resin Formed into a sheet Since parts are locally heated or cooled, it requires less time required for the heating or cooling,
The effect of good manufacturing efficiency can be obtained.

Further, the method for manufacturing an embossed sheet for a membrane switch according to claim 1 includes a step of heating a convex portion formed on the resin sheet, and heating the resin sheet at a heat distortion temperature or higher. Since the resin sheet can be more easily deformed, it is possible to overcome the variation in the embossing characteristics, which was the drawback of the method using only the cold press machine of the conventional example, and to obtain an embossing sheet having good switching characteristics. It can be manufactured.

According to the die for producing an embossed sheet according to claim 2, the die for producing an embossed sheet for use in the method for producing an embossed sheet for a membrane switch according to claim 1, wherein the die is convex on the first processed surface. One die having a portion formed therein, and the other die having a second processing surface facing the first processing surface and a space portion opening at a position corresponding to the convex portion, It is characterized in that it comprises a heating means for heating the convex portion of one mold and an air introducing means for introducing cooling air into the space of the other mold. Both heating and cooling can be performed, and as compared with the conventional method using both a hot press machine and a cold press machine, only one press machine is needed, and the burden of equipment cost is small.

Further, according to the die for manufacturing an embossed sheet according to claim 2, only the convex portion formed on the resin sheet (the convex portion formed on the first processed surface of the one die). Since it can be locally heated or cooled, the time required for heating or cooling is less than that for heating or cooling the entire mold by the method of using the conventional hot press machine and cold press machine together. And the manufacturing efficiency is good.

Further, according to the mold for producing an embossed sheet according to the second aspect, since the die has the heating means, the convex portion formed on the resin sheet is heated to a temperature not lower than the heat deformation temperature, so that the resin By making it easier to deform the sheet,
It is possible to obtain an embossed sheet having a stable embossing characteristic and good switching characteristics, and thus it is possible to overcome the disadvantage that the embossing characteristics vary when only the cold press of the conventional example is used.

According to the die for producing an embossed sheet according to a third aspect, in the die for producing an embossed sheet according to the second aspect, an opening of the space portion is formed on the second processed surface of the other die. The heat-resistant rubber is adhered by closing the end, and the wall surface forming the space of the other mold has a tapered surface in the vicinity of the opening end, the diameter of which gradually increases from the inside toward the opening end. Therefore, when the resin sheet is placed between the one die and the other die and the die is clamped, the heat-resistant rubber is the one of the die of the resin sheet. Suppressing the surface on the side opposite to the convex portion, the convex portion surface formed on the resin sheet can be made to fit into the convex portion of the one mold, which makes it easier to mold the resin sheet. Then, it is possible to form a convex portion having a desired shape on the resin sheet. That.

Further, depending on the diameter and height of the convex portion of the one die, wrinkles may be generated in the finished embossed sheet. According to the die for producing an embossed sheet according to claim 3, Since the heat resistant rubber presses down the entire surface of the resin sheet, this can be effectively prevented.

Further, according to the die for manufacturing an embossed sheet according to the third aspect, the wall surface forming the space portion of the other die gradually expands in the vicinity of the opening end from the inside toward the opening end. Since the diameter is a tapered surface, a convex portion formed on the resin sheet when the resin sheet is arranged and clamped between the one die and the other die. The mechanical stress can be easily concentrated on the rising portion of the embossed sheet, which serves as a fulcrum when the convex portion of the embossed sheet is inverted, and the rising portion of the convex portion can be particularly clearly formed into a desired shape. However, it is possible to overcome the disadvantage that the embossing characteristic and the switching characteristic are not stable when only the cold press machine is used in the conventional example.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a method for manufacturing an embossed sheet for a membrane switch which is an embodiment of the present invention and a mold for manufacturing an embossed sheet used in the method.

FIG. 2 is a bottom view showing a second processed surface of a mold that is a modified example of the present invention.

FIG. 3 is a side sectional view showing a conventional general membrane switch.

FIG. 4 is a side sectional view showing another conventional general membrane switch.

[Explanation of symbols]

7 ... Membrane switch, 8a, 8b ... Electrode, 9a ... Embossed sheet (upper electrode sheet), 21 ... Other mold,
22 ... One mold, 23 ... Resin sheet, 26 ... Space part, 26a ... Open end, 27 ... Second processed surface, 28 ... Tapered surface, 30 ... Air introducing means (pipe line), 31 ... Heat resistant rubber ,
33 ... Convex part, 36 ... Heating means (heater), 39 ... First processed surface

Claims (3)

[Claims] 1. An embossing sheet (9a) is arranged above a pair of electrodes (8a, 8b) which are arranged so as to face each other and are spaced apart from each other, and a convex portion (10) of the embossing sheet is operated to operate the electrode ( 8a, 8b) is a method for manufacturing the embossed sheet (9a) for the membrane switch (7) that opens and closes, wherein the embossed sheet (9a) is one mold (22) having a convex portion (33). ) And the other die (21) having the space (26) at a position facing the convex portion (33), sandwiching the resin sheet (23), and the one die ( 22) heating the convex portion (33) for a certain period of time to keep the convex portion formed on the resin sheet (23) at a high temperature; and after releasing the heating of the convex portion, the other mold ( 21)
Of the embossed sheet (9a) for a membrane switch, which is manufactured by introducing cooling air into the space (26) of the sheet to cool the convex portion of the resin sheet (23). . 2. A mold (21, 22) for manufacturing an embossed sheet used in the method for manufacturing an embossed sheet (9a) for a membrane switch according to claim 1, wherein a convex portion (21) is formed on the first processed surface (39). 33) on which one die (22) is formed, and a second processed surface (2) facing the first processed surface (39).
In (7), the other mold (21) in which the space (26) opening to the position corresponding to the convex part (33) is formed, and the convex part (33) of the one mold (22) are shown. Manufacturing of an embossed sheet, comprising: heating means (36) for heating; and air introduction means (30) for introducing cooling air into the space (26) of the other mold (21). Mold (21, 2
2). 3. The mold (21, 22) for producing an embossed sheet according to claim 2, wherein the second processed surface (27) of the other mold (21) is
The wall surface that closes the opening end (26a) of the space (26) and has a heat resistant rubber (31) adhered thereto and forms the space (26) of the other mold (21) is the opening end. A die (21, 22) for manufacturing an embossed sheet, characterized in that the vicinity of (26a) is a tapered surface (28) whose diameter gradually increases from the inside toward the opening end (26a).