JPH1139984A - EL illuminated switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an EL light emitting switch which can be thinned and whose mechanical life is prolonged. SOLUTION: An EL element layer 45 is formed under a sheet 41 made of a flexible and transparent synthetic resin and at the same time a sheet 21 made of synthetic resin on which a pressure sensitive film switch layer constituted of a conductive pattern 27, a pressure sensitive resistance film 25, and two electrode patterns 23, 23 is formed by printing is positioned in the lower side of the EL element layer 45. A dome spring 43 made of a transparent material is put on the sheet 41 made of the synthetic resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an EL illuminated switch.

[0002]

2. Description of the Related Art Conventionally, in order to obtain visibility in a dark place, an electroluminescent device (hereinafter, referred to as "E") has been provided on an input operation portion of a mobile phone or various remote control devices.
L ") illuminated switches have been developed.

[0003] An EL illuminated switch constitutes an EL illuminated sheet by, for example, providing an EL element layer on the entire lower surface of a transparent sheet, and a membrane switch is arranged below the EL illuminated sheet. Is pressed by a key top or a finger to lower the EL illuminating sheet and turn on / off the switch contact portion of the membrane switch.

[0004] Since the EL illuminating sheet is thin and can uniformly illuminate the entire surface of the sheet, it can not only be made thinner but also does not require chip bonding, as compared with a case where a light emitting diode is installed and illuminated. Luminance unevenness hardly occurs.

[0005]

The membrane switch is constructed by laminating contact patterns provided on two flexible sheets through holes provided in a spacer. To make this an illuminated switch, the EL illuminating sheet is mounted on the upper surface of the membrane switch.

To turn on the switch, the EL
It is necessary to press down on the illuminating sheet and push in the upper synthetic resin sheet constituting the membrane switch until its contact pattern contacts the lower contact pattern. In other words, the EL illuminating sheet has to be pushed in and bent by the thickness of the spacer.

However, if the EL illuminating sheet is depressed to bend or if the pressing is stopped and returned to the original position, a deformation load is continuously applied to the EL illuminating sheet, and its mechanical life is shortened. There was a problem that it would.

[0008] The present invention has been made in view of the above points, and an object of the present invention is to provide an EL illuminated switch which can be made thinner and has a longer mechanical life.

[0009]

In order to solve the above-mentioned problems, an EL illuminated switch according to the present invention comprises an EL element layer provided on a lower surface of a flexible transparent synthetic resin sheet and an EL element. When the pressure-sensitive resistive film is pressed in the thickness direction by having a pressure-sensitive resistive film and at least two electrode patterns formed on both or one of the surfaces of the pressure-sensitive resistive film below the layer, A pressure-sensitive membrane switch layer that changes the resistance value between the two electrode patterns is arranged. The present invention also provides the pressure-sensitive membrane switch layer,
The synthetic resin sheet on which the pressure-sensitive membrane switch layer is formed and the synthetic resin sheet on which the EL element layer is formed are formed on a synthetic resin sheet different from the synthetic resin sheet on which the element layer is formed. I decided to match. Further, in the present invention, a single EL / pressure-sensitive sheet is formed by further laminating and printing the pressure-sensitive film switch layer on the lower surface of the EL element layer formed on the synthetic resin sheet. In the present invention, a transparent dome spring is provided on the synthetic resin sheet on which the EL element layer is formed. Further, according to the present invention, an opening is provided in a portion directly above the two electrode patterns of the synthetic resin sheet on which the EL element layer is formed.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. [First Embodiment] FIG. 1 is a schematic side sectional view showing an EL illuminated switch according to a first embodiment. As shown in the figure, the EL illuminated switch is configured such that a pressure-sensitive switch 20 is placed on a hard plate 10, an EL illuminating sheet 40 is placed thereon, and a keytop 70 is placed thereon. I have. In these figures, the thickness of the sheet and each printing layer is shown to be considerably thicker than the actual one for convenience of explanation. Hereinafter, each component will be described in detail.

FIG. 2 is an assembly view of an EL illuminated switch, FIG. 3 is a plan view of a main part of a pressure-sensitive switch 20, and FIG. 4 is an enlarged view of a portion A in FIG.

First, the hard plate 10 shown in FIGS. 1 and 2 is made of, for example, a metal plate, but may be made of another hard resin plate or the like.

Next, the pressure-sensitive switch 20 is shown in FIGS.
As shown in FIG. 3, two circular electrode patterns 23 are formed on an insulating synthetic resin sheet 21, and the pressure-sensitive resistive film 2 is formed so as to cover the two electrode patterns 23.
5 and further, one conductive pattern 27 is formed on the pressure-sensitive resistive film 25 at a position facing the two electrode patterns 23 and 23. The electrode pattern 2
3, 23, the pressure-sensitive resistance film 25 and the conductive pattern 27 constitute a pressure-sensitive film switch layer.

Here, as the synthetic resin sheet 21, for example, a polyethylene terephthalate sheet (PET sheet) having a thickness of about 75 μm to 188 μm is used.

Next, the electrode patterns 23, 23 are formed by screen printing silver paste.
From one end, circuit patterns 24, 24 (see FIG. 3) formed by screen printing at the same time as the electrode patterns 23, 23 are drawn out. The electrode patterns 23, 23
Is about 10 μm in this embodiment (4 μm to 2 μm).
About 0 μm is preferable).

Next, the pressure-sensitive resistive film 25 is formed by printing a pressure-sensitive material having a function of reducing the resistance value in the thickness direction by pressing in the thickness direction, and has a thickness of 15 to 100 μm. The degree is preferred.

In the pressure-sensitive resistive film 25 according to the present embodiment,
An anisotropic pressure-sensitive resistive film whose resistance changed only in the pressing direction (that is, only in the thickness direction) and remained insulated in other directions was used. As the material of the pressure-sensitive resistance film 25, a material obtained by mixing conductive powder in an elastic material is used. Specifically, in this embodiment, silicon rubber is used as the elastic material,
Using carbon powder as conductive powder, silicon rubber 5.0
1.0 to 2.0 parts by weight of carbon powder (0.1 to 2.0 parts by weight of an insulating filler with respect to silicon depending on the case) is mixed with the high-boiling ester. Used in a solvent. Further, as the carbon powder, general carbon black in the form of fine powder in the order of submicrons is used.

The elastic material is not limited to silicone rubber, but may be other various rubber materials (eg, butadiene rubber, acrylonitrile / butadiene / styrene rubber), or thermoplastic elastomers (eg, styrene-based thermoplastic elastomer, olefin-based rubber). Materials having various elasticity such as thermoplastic elastomers), polyvinyl chloride / vinyl acetate resin materials, and polyethylene can be used.

As the material of the conductive powder, besides carbon black, spherical graphite, bead-like graphite, scale-like graphite, flake-like graphite, earth-like graphite and the like may be used, or a mixture thereof. Other conductive metal powders may be used.

The conductive pattern 27 is the same as the electrode patterns 23, 23.

Next, as shown in FIGS. 1 and 2, the EL illuminating sheet 40 is made of a transparent synthetic resin sheet 4 having flexibility.
An EL element layer 45 is provided on the entire lower surface of the device 1 and a dome spring 43 made of a transparent material is attached to the upper surface of the synthetic resin sheet 41.

Here, a method of manufacturing the EL illuminating sheet 40 will be described. That is, the EL illuminating sheet 40 has a thickness of, for example, about 75 μm to
FIG. 4 shows a synthetic resin sheet 41 made of a T sheet.
A transparent electrode layer 421 is previously formed on the entire lower surface of the transparent electrode layer 421 as shown in FIG. 3, and the phosphor layer 423, the dielectric layer 425, and the back electrode layer 427 are printed and laminated on the entire lower surface of the transparent electrode layer 421. To form an EL element layer 45, a resist layer 429 is printed and laminated on the entire lower surface of the EL element layer 45, and a dome spring 43 shown in FIGS. It is manufactured by attaching it with a sheet or the like.

Here, as the transparent electrode layer 421, for example, an ITO film (indium tin oxide film) having a thickness of about 1 μm is used. This transparent electrode layer 421 is made of a synthetic resin sheet 41.
Is deposited in advance.

The phosphor layer 423 is obtained by mixing powder of a phosphor (for example, ZnS doped with Cu) in a resin binder (for example, a resin having a high dielectric constant, for example, a cyanoethyl resin or a polyvinylidene fluoride resin). Using
Its thickness is, for example, about 50 μm.

As the dielectric layer 425, a high dielectric constant insulating material, for example, a high dielectric constant resin (for example, a cyanoethyl resin,
A mixture of a high dielectric constant filler (eg, barium titanate powder) and a polyvinylidene fluoride resin is used.

As the back electrode layer 427, for example, a carbon paste or a silver paste is used.

As the dome spring 43, for example, a PET sheet is used which is formed in a dome shape so as to be thermally deformed by being sandwiched by a mold and projecting upward.

To assemble the EL illuminated switch, as shown in FIG. 2, the pressure-sensitive switch 20 is placed on the hard plate 10, the EL illuminating sheet 40 is placed thereon, and the EL illuminating sheet 40 is Dome spring 43 attached
A transparent key top 70 made of mold resin is placed on the top. The key top 70 is vertically movably supported via an opening 61 provided in a case 60 provided on the EL illuminating sheet 40. The case 60 may be transparent or opaque.

When the key top 70 is pressed in the direction of arrow B in FIG. 1, the dome spring 43 is deformed while generating a click feeling, and the lower surface thereof presses the EL illuminating sheet 40 and the pressure-sensitive resistive film 25.

As a result, the resistance in the thickness direction of the pressed portion of the pressure-sensitive resistive film 25 is reduced, and one electrode pattern 23 → the conductive pattern 27 → the other electrode pattern 23
Circuit is turned on.

On the other hand, when the pressing on the key top 70 is released, the dome spring 43 automatically returns to the original state, and returns to the off state between the two electrode patterns 23,23.

The thickness of the pressure-sensitive resistive film 25 hardly changes even if the key top 70 is pressed. Therefore the pressed EL
The illumination sheet 40 also hardly bends. Therefore, no mechanical deformation load is continuously applied to the EL illuminating sheet 40, and the mechanical life can be extended as compared with the case where a conventional membrane switch is used.

On the other hand, between the transparent electrode layer 421 and the back electrode layer 427 (see FIG. 4) in the EL element layer 45, for example, 1
When an alternating voltage of 1 KHz is applied at 00 V, the phosphor layer 4
23 emits light, and the light is emitted from the transparent synthetic resin sheet 4.
1 and the surface of the key top 70 are brightly illuminated through the dome spring 43 and the key top 70.

Here, the reason why the dome spring 43 is mounted in this embodiment will be described. That is, the reason why the dome spring 43 is attached is, of course, to obtain a good clicking feeling when the key top 70 is pressed, but also to turn on and off the electrode patterns 23 of the pressure-sensitive switch 20 with high sensitivity. is there.

That is, the resistance value of the pressure-sensitive resistance film 25 in the thickness direction changes according to the pressing force for pressing the pressure-sensitive resistance film 25. That is, if the pressing force is weak, there is a possibility that the two electrode patterns 23 may not be turned on even if the pressing is intended.

Then, if the dome spring 43 is attached, if it is pushed to the depth where the clicking feeling is generated,
The conductive pattern 27 is pressed by a predetermined concentrated strong impact force by the reversing force of the dome spring 43, so that the resistance value between the two electrode patterns 23, 23 can be reliably reduced to a resistance value that can be turned on. That is, on / off switching can be performed reliably.

The structure of the pressure-sensitive switch 20 is not limited to the above-described embodiment, and various other structures can be used. For example, as shown in FIG. The patterns 23a and 23b may be provided (therefore, the conductive pattern 27 is omitted), so that the two electrode patterns 23a and 23b are turned on and off. In this case, the electrode patterns 23a and 23b and the pressure-sensitive resistive film 25 constitute a pressure-sensitive film switch layer.

[Second Embodiment] FIG. 6 is an assembly view of an EL illuminated switch according to a second embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The difference of this embodiment from the first embodiment is that the conductive pattern 27 is not formed on the pressure-sensitive resistive film 25 but is printed on the lower surface of the resist layer 429 of the opposing EL illuminating sheet 40. Only the formed points.

With such a configuration, the same operation as in the first embodiment is performed. In the case of this embodiment, the pressure-sensitive resistive film 25 and the conductive pattern 27 are not bonded at all, and are simply in contact with each other. Therefore, the contact resistance value at the contact surface between the two is large.

For this reason, even if a material having high sensitivity as the material of the pressure-sensitive resistance film 25, that is, a material whose resistance value is easily changed with respect to a change in stress, is used, the contact resistance value can be kept large. In the state, both electrode patterns 23, 2
3 can be reliably kept in the off state.

On the other hand, when the conductive pattern 27 is pressed from above, the space between the two electrode patterns 23 is turned on as described above. At this time, the conductive force is applied to the pressure-sensitive resistive film 25 by the pressing force. Since it is strongly pressed, the contact resistance value at the contact surface between the two becomes small. At the same time, as described above, a highly sensitive pressure-sensitive resistive film 25 can be used.
In response to the pressing, the space between the two electrode patterns 23 is immediately turned on.

That is, in the present embodiment, the conductive patterns 27 are not printed on the pressure-sensitive resistive film 25, but are formed on separate substrates and then overlapped so that they are in contact with each other. Even if a good pressure-sensitive resistive film 25 is used, the resistance between the two electrode patterns 23 can be kept large in the non-pressed state, and the OFF state can be reliably maintained. Can be turned on.

When the present embodiment is applied to the pressure-sensitive switch 20 having the configuration in which the electrode patterns 23a and 23b are provided above and below the pressure-sensitive resistive film 25 as shown in FIG. 5, the upper electrode pattern 23a faces the EL. What is necessary is just to print and form on the lower surface of the resist layer 429 of the illumination sheet 40.

[Third Embodiment] FIG. 7 is an assembly view of an EL illuminated switch according to a third embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The difference between this embodiment and the first embodiment is that the entire lower surface of the synthetic resin sheet 41 is EL
An element layer 45 is provided, and a conductive pattern 27, a pressure-sensitive resistive film 25, and two electrode patterns 23, 23 are further laminated and printed in this order on the lower surface of the resist layer 429 printed below the EL element layer 45. The point is that the pressure-sensitive film switch layer is formed, and the resist layer 31 is further formed by printing on the lower surface thereof, thereby forming the EL / pressure-sensitive sheet 50.

Then, the EL / pressure-sensitive sheet 50 is placed on the hard plate 10, while the dome spring 43 is mounted on the upper surface of the EL / pressure-sensitive sheet 50, and the key top 70 is further disposed thereon. , The EL illuminated switch is completed.

In this embodiment, the switch can be turned on and off in the same manner as in the first embodiment.

According to this embodiment, compared to the first and second embodiments, the lower surface of one synthetic resin sheet 41 can have two functions only by the printing process.
The number of parts can be reduced, the structure can be simplified, the thickness can be reduced, and the assembly cost can be reduced.

In this embodiment, as shown in FIG. 5, the electrode patterns 23 are formed above and below the pressure-sensitive resistive film 25.
a, 23b may be provided.

[Fourth Embodiment] FIG. 8 is a schematic side sectional view of an EL illuminated switch according to a fourth embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

This embodiment is different from the first embodiment in that the dome spring 43 is mounted directly on the pressure-sensitive switch 20 with an adhesive tape (not shown) or the like, and a circular opening 49 is provided thereon. This is the point where the illumination sheet 40 is placed. At this time, the dome spring 43 is
Exposed from 9.

According to this structure, the key top 70 is pressed to invert the dome spring 43 and the pressure-sensitive switch 20 is turned on.
When the button is pressed, the pressing force does not press the EL illuminating sheet 40 at all, so that the switch on / off sensitivity is further improved as compared with the above embodiments, and at the same time, the EL illuminating sheet 4 is pressed.
Since no mechanical damage is given to 0, the life can be extended.

[Fifth Embodiment] FIG. 9 is a schematic sectional side view of an EL illuminated switch according to a fifth embodiment. In the case of this embodiment, the pressure-sensitive switch 20 and the EL illuminating sheet 40 are mounted on the hard plate 10 as in the first embodiment, and the dome spring 43 and the key top 70 are arranged thereon. The difference is that a circular opening 49 is provided in a portion directly below the dome spring 43 of the EL illuminating sheet 40.

With this configuration, as in the fourth embodiment shown in FIG. 8, the switch ON / OFF sensitivity is improved, and at the same time, the EL illuminating sheet 40 is not mechanically damaged.

[0056]

As described in detail above, the present invention has the following excellent effects. By stacking the EL element layer and the pressure-sensitive membrane switch layer, the EL
Since the illuminated switch is configured, not only the thickness can be reduced, but also the EL element layer pressed when the switch is turned on and off by pressing the EL element layer hardly bends, and the life of the EL illuminated switch can be extended.

When a transparent dome spring is provided on a synthetic resin sheet provided with an EL element layer, it is transparent, so that light can be uniformly radiated from directly beneath, and there is little unevenness in brightness. With the concentrated strong impact force, the pressure-sensitive membrane switch layer can be reliably switched on and off.

When one EL / pressure-sensitive sheet is formed by sequentially laminating and printing an EL element layer and a pressure-sensitive film switch layer on the lower surface of one synthetic resin sheet, the number of parts can be further reduced. The thickness can be further reduced, and the assembly cost can be reduced.

When an opening is provided in the EL element layer immediately above the two electrode patterns, no pressing force is applied to the EL element layer at the time of switching on and off, so that the on / off sensitivity is improved and the EL element is simultaneously improved. Since the layer is not mechanically damaged, the life can be extended.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view showing an EL illuminated switch according to a first embodiment.

FIG. 2 is an assembly view of an EL illuminated switch.

FIG. 3 is a plan view of a main part of the pressure-sensitive switch 20.

FIG. 4 is an enlarged view of a portion A in FIG. 2;

FIG. 5 is an assembly view of an EL illuminated switch using a pressure-sensitive switch 20 having another structure.

FIG. 6 is an assembly view of an EL illuminated switch according to a second embodiment.

FIG. 7 is an assembly view of an EL illuminated switch according to a third embodiment.

FIG. 8 is a schematic side sectional view of an EL illuminated switch according to a fourth embodiment.

FIG. 9 is a schematic side sectional view of an EL illuminated switch according to a fifth embodiment.

[Explanation of symbols]

 Reference Signs List 10 hard plate 20 pressure-sensitive switch 21 synthetic resin sheet 23, 23 electrode pattern 25 pressure-sensitive resistive film 27 conductive pattern 40 EL illumination sheet 41 synthetic resin sheet 43 dome spring 45 EL element layer 49 opening 50 EL / pressure-sensitive sheet 70 key top

Claims (5)

[Claims] An EL element layer is provided on the lower surface of a transparent synthetic resin sheet having flexibility, and a pressure-sensitive resistive film and / or both sides of a pressure-sensitive resistive film are provided below the EL element layer. A pressure-sensitive membrane switch layer that has at least two electrode patterns formed on the surface of the pressure-sensitive resistive film and changes a resistance value between the two electrode patterns when the pressure-sensitive resistive film is pressed in a thickness direction. An EL illuminated switch characterized by the following: 2. The synthetic resin sheet in which the pressure-sensitive membrane switch layer is formed on a synthetic resin sheet different from the synthetic resin sheet on which the EL element layer is formed, and the pressure-sensitive membrane switch layer is formed. 2. The EL illuminated switch according to claim 1, wherein the sheet and a synthetic resin sheet on which an EL element layer is formed are overlapped. 3. An EL / pressure-sensitive sheet is formed by further laminating and printing the pressure-sensitive film switch layer on the lower surface of an EL element layer formed on the synthetic resin sheet. Item 9. An EL illuminated switch according to Item 1. 4. The EL illuminated switch according to claim 1, wherein a transparent dome spring is provided on the synthetic resin sheet on which the EL element layer is formed. 5. The EL device according to claim 1, wherein an opening is provided at a position directly above the two electrode patterns of the synthetic resin sheet on which the EL element layer is formed. Illuminated switch.