JP2010118200A - Keyswitch, and electronic display equipment equipped with its keyswitch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a key switch superior in moisture resistance and capable of obtaining a superior click feeling. <P>SOLUTION: A key display body 20 which has a plurality of key display parts in which key display is variable and which has flexibility, a push-down member 30 having a plurality of hemispherical and protruding push-downs 32, and a switch sheet 40 in which a plurality of metal dome springs 43 are installed on an FPC substrate 41 are laminated, and its outer surface is covered to form a package by a covering membrane 50 composed of at least one of moisture-resistant material. The covering membrane 50 is constituted of the covering membrane 50A on a key display body side, and the covering membrane 50B on a switch sheet side, and the covering membrane 50B on the switch sheet side is adhered and fixed to the FPC substrate 41. Moreover, the covering membrane 50B on the switch sheet side is formed of a resin sheet at which a rigid membrane is installed, a metal thin membrane, and a metal plate or the like. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a key switch and an electronic display device including the key switch, and more particularly to a key switch in which key display is variable and the humidity resistance of the key switch is enhanced.

As a key switch of an electronic display device such as a mobile phone or a PDA, one of the conventionally known key switches is configured as shown in FIG. 9 (see, for example, Patent Document 1). 9 includes a switch sheet 1300 disposed on a circuit board 1400, an electronic paper 1200 disposed on the switch sheet 1300, and a transparent key sheet 1100 disposed on the electronic paper 1200. The configuration is arranged.
In addition, a predetermined number of convex and transparent key tops 1101 are integrally formed on the key sheet 1100 so as to look into the upper surface of the casing from a predetermined opening 1501 of the casing 1500 of the key input device. Is configured to have a member 1301 that gives a click feeling.
Further, the electronic paper 1200 is energized by the wiring 1201 from the circuit board 1400.

  The electronic paper 1200 uses an electrophoretic microcapsule type or an electrophoretic black-and-white rotating particle type, and can recognize display characters composed of white and black.

  The key switch having the above configuration presses the key top 1101 at the position of the predetermined display character displayed on the electronic paper 1200 with a finger or the like, thereby causing the click feeling of the electronic paper 1200 and the switch sheet 1300 at that position. The member 1301 to be applied is pressed, and the member 1301 to provide a click feeling is bent to be switched on.

JP 2005-352987 A

  The key switch having such a configuration has the following problems. The first problem is that the water resistance and moisture resistance are not sufficient. Water is likely to enter from the opening 1501 of the housing 1500, and moisture is also likely to occur. For this reason, the microcapsules of the electronic paper 1200 are deteriorated due to moisture and normal driving is not performed, and the member 1301 that gives a click feeling is likely to be deteriorated such as corrosion. Thus, if the moisture resistance is poor, performance deterioration is likely to occur, and quality cannot be maintained over a long period of time.

  The second problem is that a good click feeling cannot be obtained. This configuration has a structure in which a member 1301 having a dome-shaped click feeling is pressed with a flat electronic paper 1200. That is, the electronic paper 1200 has a structure in which the flat surface of the electronic paper 1200 is pressed against the roof of the dome ceiling. In the structure using such a pressing method, the click rate is low, and a good click feeling cannot be obtained.

  As a third problem, since the electronic paper 1200 has a structure that directly presses the member 1301 that gives a click feeling, the electronic paper 1200 directly receives a reaction force from the member 1301 that gives a click feeling, that is, a drag. Since the member 1301 that gives a click feeling has a dome shape, the part of the electronic paper 1200 that receives the resistance varies, and the degree of the force also varies. For this reason, the electronic paper 1200 is likely to be deformed or deteriorated in performance.

  As a fourth problem, a positional deviation between the center position of the key top 1101 and the central position of the display unit of the electronic paper 1200, and a positional deviation between the center position of the key top 1101 and the center position of the member 1301 that gives a click feeling. It is easy to cause positional deviation such as. This structure has a structure in which a key sheet 1100 provided with a key top 1101, an electronic paper 1200, and a switch sheet 1300 provided with a click feeling member 1301 are stacked and stored in a casing 1500. For this reason, positional deviation occurs due to variations in the dimensional accuracy of each part and variations in assembly accuracy. In order to suppress this displacement, it is necessary to strictly manage the dimensional accuracy of each component.

  In addition, in patent document 1, although the thing of the structure which has arrange | positioned electronic paper on each keytop as another structure is shown, under this structure, electronic paper is exposed to the outer side of a housing | casing. Therefore, damage such as scratches is likely to occur. Moreover, the problem that electronic paper peels from a keytop also arises.

  The present invention has been made in view of the above problems, and its object is to improve the moisture resistance of the key switch so that a stable quality can be obtained over a long period of time, and at the same time, a good click It is to obtain a key switch that gives a feeling.

  As a means for solving the above-mentioned problems and achieving the above-mentioned object, the key switch of the present invention has a plurality of key display portions, the key display can be changed, and the flexible key display body has a back side. A key switch in which a pusher member having a plurality of hemispherical projecting pushers is disposed, and a switch sheet provided with a plurality of metal dome springs on the FPC board below the pusher member, The outer surface of the key switch has a coating film made of at least one moisture resistant material.

Under the above configuration, when the key display portion of the key display body covered with the coating film is pressed, the key display body is bent, and at the same time, the presser of the presser member is pressed by the bent key display body. Then, the pressed pusher presses the metal dome spring of the switch sheet, and the metal dome spring bends. The bent metal dome spring contacts the switch electrode pattern of the FPC board (Flexible Printed Circuit Board) and switches on.
Here, since the key display of the key display can be changed, various characters such as numerals, hiragana, katakana, English characters, and symbols can be displayed by a character switching operation. Further, since the key display body has flexibility, it is possible to directly perform a keystroke operation with a finger or the like.

Further, the pusher of the pusher member has a hemispherical shape. Since the pusher has a spherical shape, the metal dome spring is first pushed by the tip of the pusher's spherical surface and then pushed along the spherical surface. Therefore, the metal dome spring is not damaged, and a large force is not applied only to a specific portion, so that the life of the metal dome spring can be maintained long.
Moreover, when such a shape is taken, the click rate becomes high and the click feeling appears well.

In addition, a reaction force from the metal dome spring, that is, a drag acts on the pusher, but this drag is also transmitted to the key display and affects the key display.
The drag acting on the key display body is greatly influenced by the size of the area of the projection base of the hemispherical projection of the pusher. If the area of the protrusion root is large, the drag is dispersed and the drag per unit area acting on the key display body is reduced. Conversely, if the area of the protrusion root is small, the drag per unit area acting on the key display body is increased. .
Therefore, the area of the protrusion root can be increased by making the shape of the pusher into a hemispherical shape. Then, by setting the area of the protrusion base large, the drag per unit area acting on the key display body is reduced, and the deformation and quality deterioration of the key display body can be minimized.

In addition, since the outer surface of the key switch configured as described above has a coating film made of a moisture resistant material, the moisture resistance performance is further improved, and the performance of the key display body and the switch sheet can be maintained over a long period of time.
Further, the key switch can be packaged in a flat shape by the coating film. The packaged key switch can be easily handled for transportation and built into electronic display devices.
In addition, the key display body, the pusher member, and the switch sheet are packaged with their positions aligned in advance, so that the position of the key display portion of the key display body, the position of the pusher member of the pusher member, and the position of the pusher and the switch Position accuracy such as the position of the metal dome spring of the sheet can be increased. And generation | occurrence | production of position shift can be suppressed also in long-term use.

  In the key switch of the present invention, the key display body side coating film that the coating film on the outer surface of the key switch has on the outer surface side of the key display body and the switch sheet side that the outer surface side of the switch sheet has The switch sheet side coating film is fixed to the FPC board.

The FPC board provided with the switch electrode pattern has flexibility. For this reason, when the metal dome spring is pressed by the pusher, the FPC board is bent together with the bending of the metal dome spring, so that it is difficult to turn on the switch.
Here, since the switch sheet side coating film is fixed to the FPC board, the bending strength of the FPC board is reinforced by the switch sheet side coating film and becomes large. That is, the strength of the FPC board is increased and the bending of the FPC board is reduced. For this reason, the metal dome spring is normally bent and the switch is easily turned on. In addition, since the reaction force from the metal dome spring is increased, the click rate is also increased.

  In the key switch of the present invention, the key display body side coating film that the coating film on the outer surface of the key switch has on the outer surface side of the key display body and the switch sheet side that the outer surface side of the switch sheet has The bending strength of the switch sheet side coating film is greater than the bending strength of the FPC board.

This structure is a structure in which a switch sheet side coating film larger than the bending strength of the FPC board is laminated under the FPC board. Therefore, when the switch sheet side coating film is bonded and fixed to the FPC board, a bending strength of twice or more can be obtained, and the bending of the FPC board can be suppressed to a small value. In addition, when the switch sheet side coating film is several times larger than the bending strength of the FPC board, for example, a metal plate is used, the switch sheet side coating film is not bonded and fixed to the FPC board. The bending of the FPC board can be kept small by being restricted by the covering film.
As a result, the metal dome spring can be bent normally, and the switch can be easily turned on. In addition, since the reaction force from the metal dome spring is increased, the click rate is also increased.

  The key switch of the present invention is characterized in that the switch sheet side coating film is formed by providing a hard film on the surface of a resin sheet.

Bending strength can be increased by providing a hard film on the surface of the resin sheet. That is, the bending elasticity of the coating film is increased. The effects as described above can be obtained.
Examples of the hard film include films such as SiO ₂ and Al ₂ O ₃ .

  The key switch of the present invention is characterized in that the switch sheet side coating film is made of a metal foil film or a metal plate.

  Similarly, even if the coating film is formed of a metal foil film or a metal plate, the bending elasticity of the coating film is enhanced. In this case, it is preferable to use a metal with good moisture resistance, and examples thereof include aluminum and stainless steel. Furthermore, aluminum can be said to be more suitable in consideration of lightness.

  The key switch of the present invention is characterized in that the pusher member has a sheet shape.

  When the pusher member has a sheet shape, the handling is easy, and the key switch can be easily assembled. The effect of reducing assembly man-hours is obtained.

  The key switch of the present invention is characterized in that the key display body is any one of an electrophoretic display panel, a liquid crystal display panel, and an electroluminescence display panel.

  Electrophoretic display panels, liquid crystal display panels, and electroluminescence display panels can form various key display characters. In addition, the key display character can be changed by a simple key operation. Moreover, since the size of the key display character can be arbitrarily set, it is possible to unify the characters into a size that is easy to see.

  In the key switch of the present invention, the electrophoretic display panel has a microcapsule layer between upper and lower flexible substrates, and at least in the region of the key display portion, the microcapsule layer and the lower A cushion layer is provided between the substrate and the substrate.

  By providing a cushion layer having elasticity between the microcapsule layer and the lower substrate, the microcapsule layer is disposed on the cushion layer. In other words, the microcapsule comes on the cushion. When the key display portion is pressed with a finger or the like, the microcapsule is pressed, and the pressed microcapsule sinks into the cushion layer. For this reason, the force applied to the microcapsules is alleviated so that the capsules are not deformed.

  The key switch of the present invention is characterized in that the cushion layer is made of a rubber-based resin.

  Since rubber-based resin is rich in elasticity, it can be applied as a suitable cushioning material. Further, it can be easily formed on the lower substrate by a printing method or the like.

  The key switch according to the present invention is characterized in that the electrophoretic display panel has a notch in the lower substrate in a region removed from the key display.

  This notch is provided so that the lower substrate of the key display portion can be easily bent by pressing. Therefore, it is preferable that the shape of the notch is a shape that makes the lower substrate bend easily. By providing such a notch, pressing the key display unit makes it easy for the key display body at the part of the key display unit to bend, and the presser provided on the back side of the key display unit can be pushed down smoothly. become.

  In the key switch of the present invention, the electroluminescence display panel includes a light emitter layer between flexible upper and lower substrates, and a cutout portion is formed in the lower substrate in a region away from the key display portion. It is characterized by having.

  This is due to the same reason as the notch provided on the lower substrate of the electrophoretic display panel. The electroluminescence display panel can obtain the same effect as that of the electrophoretic display panel.

  An electronic display device provided with the key switch of the present invention is characterized in that the key switch uses the key switch described above.

  By incorporating the key switch of the present invention into an electronic display device, the key switch function in the electronic display device has good moisture resistance, can maintain stable quality over a long period of time, and a good click feeling can be obtained. In addition, since the key switch is packaged, it can be easily incorporated into equipment.

Although the effects have been described in detail for each invention item above, when summarized roughly, the moisture resistance performance is improved and the drag acting on the key display body is reduced, so the deterioration of the quality of the key display body and the switch sheet is suppressed and good over a long period of time. Quality can be maintained.
In addition, a good click feeling can be obtained, and the key switch can be packaged, so that it is easy to handle the key switch and assemble it into an electronic display device. In addition, positional accuracy such as misalignment in the key display body, pusher member, and switch sheet stacking can be improved.

  Embodiments for carrying out the present invention will be described below with reference to FIGS. 1 is a plan view showing an example of a key switch panel of a mobile phone according to the present embodiment, FIG. 2 is a cross-sectional view schematically showing the main part of the key switch in FIG. 1, and FIG. -A shows a cross-sectional view.

First, as shown in FIG. 1, the key switch panel 10 of the mobile phone according to the present embodiment is provided with a plurality of openings in a required portion of the cover 11 of the housing, and the key switch 12 is opened from the openings. The key display characters (including symbols and marks) are visible. S in the figure indicates a key display portion of the key switch, and the key display characters displayed on the key display portion S can be seen from the opening.
A feature of the key switch panel 10 in the present embodiment is that there is a character switch mode key switch (displayed as “display” in FIG. 1) for display character switching. By pressing this “display” key switch, various characters such as numerals, hiragana, katakana, English letters, and symbols can be displayed.

In addition, as shown in FIG. 2, the configuration of the key switch 12 of this embodiment includes a pusher member 30 provided with a pusher 32 on an adhesive sheet 31 on the back side of the key display body 20. A switch sheet 40 provided with a metal dome spring 43 is disposed on the FPC board 41 below, and the outer surfaces of the laminated key display 20, pusher member 30, and switch sheet 40 are covered with a moisture resistant material. The structure covered with the film 50 is made.
The key display body 20 here is an electrophoretic display panel, and has a configuration in which a microcapsule layer 23 is provided between an upper substrate 21 and a lower substrate 22 facing each other and sealed with a sealing material 24. Since the upper substrate 21 and the lower substrate 22 have a configuration using a thin PET (polyethylene terephthalate) film, the electrophoretic display panel has flexibility. Although not shown, the key display 20 including an electrophoretic display panel has a plurality of key displays as shown in FIG.
The coating film 50 is formed by integrally joining a key display body side coating film 50A covering the outer surface of the key display body 20 and a switch sheet side coating film 50B covering the outer surface of the switch sheet on the outer periphery. ing. In the present embodiment, the key display member side coating film 50A is formed of a transparent PET film having a thickness in the range of 100 to 150 μm, and the switch sheet side coating film 50B is an aluminum metal foil film having a thickness in the range of 50 to 100 μm. It is formed with.
Although not shown, a part of the FPC board 41 of the switch sheet 40 is exposed to the outside from the joint portion of the key display body side coating film 50A and the switch sheet side coating film 50B. The drive wiring pattern of the key display body 20 which is a display panel is also exposed to the outside and connected to the drive circuit.

The above configuration will be described in more detail with reference to FIG. In FIG. 3, a key display body 20 composed of an electrophoretic display panel has a configuration in which a microcapsule layer 23 is provided in a fixed gap between an upper substrate 21 and a lower substrate 22 facing each other. The microcapsule layer 23 is formed by arranging the microcapsules 23a without gaps.
The upper substrate 21 has a configuration in which a transparent electrode 21b made of an ITO film is provided on the lower surface of a film substrate 21a made of a film such as a transparent PET film, and a protective film 21c made of polyimide resin is provided thereon. The lower substrate 22 is provided with a transparent electrode 22b made of an ITO film formed in a matrix using a TFT element on a film substrate 22a made of a film such as a transparent PET film, and a protective film 22c made of a polyimide resin thereon. The configuration is provided. The microcapsule layer 23 has a configuration in which the microcapsules 23a are aligned and fixed without any gaps with the adhesive 23b.

In the present embodiment, the transparent electrode 22b made of an ITO film formed in a matrix using the TFT elements of the lower substrate 22 is provided only in the area of the key display portion S and in the vicinity thereof, and the cover 11 A wiring pattern for providing conduction to the transparent electrode 22b is provided in a portion hidden behind and completely invisible.
The protective films 21c and 22c are provided for the purpose of protection to prevent breakage such as cracks in the transparent electrode made of the ITO film. The transparent electrode of the ITO film formed on the film substrate is likely to be damaged such as a crack due to the bending deformation of the film. The transparent electrode is protected against damage by covering the transparent electrode with a polyimide resin or urethane resin having adhesiveness and ductility characteristics and excellent flexibility resistance. The protective films 21c and 22c are formed with a film thickness in the range of 0.5 to 1.5 μm.

  The microcapsule 23a of the microcapsule layer 23 is encapsulated in a state where white particles made of titanium oxide and black particles made of carbon black are dispersed in a liquid such as silicone oil inside a capsule shell made of methacrylic acid resin or urea resin. Made up of. Titanium oxide, which is a white particle, has a positive charge, and carbon black, which is a black particle, has a negative charge. The size of the microcapsule 23a is usually 30 μm to 60 μm.

The key display body 20 having the above-described configuration selectively applies black and white character images formed in black and white by selectively applying an electric field to the transparent electrode 21b of the upper substrate 21 and the transparent electrode 22b of the lower substrate 22. A display is obtained.
Moreover, since the film substrates 21a and 22a are formed from a PET film having a thickness of 100 to 200 μm, the film substrates 21a and 22a have flexibility, and the key display body bends when pressed with a finger or the like.

Since the electrophoretic display panel as the key display body 20 has an electrode configuration using TFT elements, various key characters can be displayed. Various characters such as numbers, hiragana, katakana, English letters, and symbols can be switched using the “display” key switch.
In addition, although the key display body of this embodiment uses an electrophoretic display panel, a liquid crystal display panel, an electroluminescence display panel, etc. can also be applied as a key display body. The liquid crystal display panel can display color key characters by incorporating a color filter, and the electroluminescence display panel can display luminescent characters.

  In the present embodiment, the electrode of the lower substrate 22 is configured by the transparent electrode 22b formed of an ITO film, but the electrode at this portion is not necessarily a transparent electrode. For example, there is no problem even if it is composed of a copper thin film. When the electrode is composed of a copper thin film, there is no need to provide the protective film 22c because the risk of the copper thin film being bent and causing damage such as a crack is small.

Next, the pusher member 30 is formed by forming a plurality of pushers 32 projecting in a hemispherical shape (for the number of key display portions) on a thin adhesive sheet 31. The pusher 32 is provided at a portion of the key display body 20 that faces the key display portion.
In this embodiment, the pusher 32 is made of a resin excellent in heat resistance, moisture resistance, impact resistance, chemical resistance, etc., for example, a resin such as polycarbonate resin or acrylic resin, and has a spherical shape protruding in a hemispherical shape. It has a shape. The pusher 32 is formed by a screen printing method, a potting method, or the like. The height of the protrusion of the pusher 32 and the area of the protrusion base 32a (the portion indicated by a thick line in FIG. 3) are important management elements. Therefore, ink having a certain viscosity is used.
The adhesive sheet 31 is attached to the back surface of the key display body 20 so that the key display body 20 and the pusher member 30 are integrated.

In this embodiment, the pusher member is composed of a pusher formed on an adhesive sheet. However, the pusher may be formed simply on a resin sheet.
Moreover, you may comprise a pusher member only with a pusher. In this case, a pusher is directly formed on the back surface of the key display body by a screen printing method or a potting method.

Next, the switch sheet 40 has a configuration in which a metal dome spring 43 is provided on a portion of the FPC board 41 on which the switch electrode pattern 42 is formed, and a fixing sheet 44 for fixing the metal dome spring 43 is provided. .
The metal dome spring 43 is formed of an elastic conductive metal material. When the metal dome spring 43 is pressed from above, the metal dome spring 43 bends and comes into contact with the switch electrode pattern 42 to conduct electricity between the switch electrode patterns 42. Figured. Further, when the pressing is released, the metal dome spring 43 is released from the bending and returns to its original shape.
The metal dome spring 43 and the pusher 32 are provided at a portion facing (facing).

In the configuration of the pusher member 30 and the switch seat 40 described above, when the metal dome spring 43 is pressed by the pusher 32, the metal dome spring 43 bends and contacts the switch electrode pattern 42, and conduction is performed and the switch is turned on.
Since the metal dome spring 43 has an elastic force, a reaction force acts on the pusher 32 when pressed by the pusher 32. That is, an upward drag acts on the pusher 32. This drag will eventually act on the key display 20 through the area of the projection base 32a of the hemispherical projection of the pusher 32.
Therefore, when the area of the protrusion root 32a is small, the drag per unit area acting on the key display body 20 increases, and when the area of the protrusion root 32a is large, the drag per unit area acting on the key display body 20 decreases.
The microcapsule 23 where the drag acts on the key display body 20 also receives a pressing force from above. That is, the force is received from both above and below. And the microcapsule 23 of the part which receives a big drag becomes easy to produce the capsule shape deformation.
Therefore, when the pusher 32 is formed into a spherical shape projecting in a hemispherical shape and the area of the projection base 32a is set large within an allowable range, the drag per unit area acting on the key display body 20 is reduced, and the capsule is deformed. Can be minimized.

Further, since the pusher has a hemispherical spherical shape, the metal dome spring is first pushed at the tip of the pusher spherical surface and then is pushed along the spherical surface. For this reason, the metal dome spring is not damaged, and a large force is not applied only to a specific portion, so that the life of the metal dome spring can be maintained for a long time.
Moreover, when such a shape is taken, the click rate becomes high and the click feeling appears well.

Next, the coating film 50 includes a key display body side coating film 50A that covers the outer surface of the key display body 20 and a switch sheet side coating film 50B that covers the outer surface of the switch sheet. Bonding is performed on the outer periphery of the switch via adhesive.
Further, as described above, the key display body side coating film 50A is made of a transparent PET film having a thickness in the range of 100 to 150 μm, and the switch sheet side coating film 50B is an aluminum metal foil film having a thickness in the range of 50 to 100 μm. It is composed. The switch sheet-side coating film 50B has a structure in which the switch sheet 40 is bonded and fixed to the FPC board 41 of the switch sheet 40.
The PET film of the key display member side coating film 50A has excellent performance in moisture resistance, impact resistance, chemical resistance, etc., and therefore can be suitably applied as a coating film, and may be as thin as 100 to 150 μm. It has flexibility. Moreover, since the aluminum metal foil film of the switch sheet side coating film 50B is also excellent in moisture resistance, a moisture resistance effect is obtained. Further, although it is a thin metal foil film having a thickness of 50 to 100 μm, by bonding to the FPC board 41, the bending strength of the FPC board 41 with the aluminum metal foil film is strengthened and increased, and the bending of the FPC board 41 is reduced. Can be suppressed.

  Since the flexible FPC board 41 is used as the switch board, when the metal dome spring 43 is pressed by the pusher 32, the FPC board 41 is bent and it becomes difficult to turn on the switch. However, by sticking the aluminum metal foil film to the FPC board 41 and fixing it, the strength of the aluminum metal foil is added and the strength is reinforced, and the bending of the FPC board 41 is suppressed to a small level. And it becomes easy to switch on. Moreover, since the reaction force of the metal dome spring 43 is increased thereby, the click rate is further increased. As a result of various tests, it has been confirmed that the click rate can be increased by about 10% when an aluminum metal foil film having a thickness of 50 μm is pasted.

In the electrophoretic display panel, when moisture enters the microcapsule, the movement of particles deteriorates and it does not start, causing a display defect. Similarly, when moisture enters the switch sheet 40, the metal dome spring 43 and the switch electrode pattern 42 of the FPC board 41 are changed in quality to cause poor conduction.
However, when the coating film is configured as described above, the moisture resistance performance is greatly improved and stable quality can be obtained over a long period of time. Further, the click rate is further improved, and a good click feeling can be obtained.

Furthermore, the key switch can be packaged by the coating film 50. The packaged key switch has advantages such as ease of handling and ease of incorporation into a key switch panel of an electronic display device.
Further, since the key display body 20, the pusher member 30, and the switch sheet 40 are packaged with their positions aligned, the positional accuracy of the key display portion and the pusher 32, the positional accuracy of the pusher 32 and the metal dome spring 43, and the like. The accuracy is improved.

In the present embodiment, a thin aluminum metal foil film is used for the switch sheet side coating film 50B, but it is not limited to the aluminum metal foil film. For example, the same effect can be obtained even if a resin film provided with a hard film is attached to the FPC board 41 and used. Examples of the hard film include a SiO ₂ film and an Al ₂ O ₃ film.
It is also possible to select a metal plate having excellent corrosion resistance such as an aluminum metal plate or a stainless metal plate thicker than the metal foil film as the sheet-side coating film 50B. When a metal plate is used, it has rigidity and high bending strength. Therefore, it is not necessary to adhere to the FPC board, and a similar effect can be obtained simply by superimposing them. In order to reduce the weight of the key switch as much as possible, it is preferable to use an aluminum metal plate.

  In the present embodiment, a PET film is used for the key display body side coating film 50A. However, in addition to the PET film, for example, a resin film such as a polyethylene resin, a polypropylene resin, a polyimide resin, or a polycarbonate resin can be used. .

Here, by providing the key display body side coating film 50A on the key display body 20, the bending strength of the key display body 20 is increased (strong). Therefore, in order to obtain the required deflection (amount) of the key display body 20, it is necessary to make the pressing force of the key display portion larger (stronger) than the pressing force when the key display body side coating film 50A is not provided. It is said.
However, when the pressing force is increased, the force applied to the microcapsule 23a is increased, and the risk that the microcapsule 23a is deformed increases. In addition, when the pressing force increases, finger pain and fatigue are also born.
Therefore, a configuration that suppresses the deformation of the microcapsule 23a, a configuration that can perform a keystroke operation with a low pressing force, and the like are required.

FIG. 4 shows a cross-sectional view of the main part of the key switch mentioned as a configuration for suppressing the deformation of the microcapsule.
In FIG. 4, reference numeral 120 denotes a key display body, which differs from the configuration of the key display body 20 shown in FIG. 3 only in the configuration in which a cushion layer 125 is provided between the lower substrate 22 and the microcapsule layer 23. . That is, the key display body 120 is configured by providing the cushion layer 125 under the microcapsule layer 23.

The cushion layer 25 here is formed by a printing method such as a screen printing method using a soft rubber-based resin, for example, a resin such as polyurethane resin or nitrile rubber (NBR).
This cushion layer 125 is provided to relieve the force applied to the microcapsule 23a by pressing and suppress the deformation, and the pressed microcapsule 23a bites into the soft cushion layer 125 to reduce the deformation of the microcapsule 23a. Is done.

  Since the cushion layer 125 only needs to be in the area of the key display portion where the keystroke operation is performed, in this embodiment, it is provided only in the area of the key display portion. However, there is no problem even on the entire surface of the lower substrate 22.

  By adopting the configuration as described above, the microcapsule 23a pressed by the keystroke operation bites into the soft cushion layer 125, and when the pressure is released, the microcapsule 23a is restored to its original state by the restoring force of the cushion layer 125. Return. As a result, the deformation of the microcapsule 23a can be minimized.

  Next, a configuration capable of a keystroke operation with a low pressing force will be described with reference to FIGS. FIG. 5 is a cross-sectional view of the main part of the key switch showing a configuration that can reduce the pressing force, and FIG. 6 is a plan view of the main part of the lower substrate in FIG.

  As shown in FIG. 5, a feature of the configuration in which the pressing force can be reduced is that a notch portion 132 a is provided on the lower substrate 132 of the key display body 130 in a region removed from the key display portion. The lower substrate 132 is composed of a transparent electrode and a protective film formed in a matrix using a film substrate and TFT elements, and this transparent electrode is provided only in the key display area. A cutout portion 132a is provided in a region that is outside the key display portion and does not affect the wiring pattern connected to the transparent electrode.

  FIG. 6 is a view showing an example of the notch. In FIG. 6, S is a key display portion, and the inside of an ellipse indicated by a chain line is the key display portion S. A cutout portion 132 a made up of a U-shaped slit is provided in an area outside each key display portion S so as to surround the key display portion S. The part provided with the notch 132a is also a part without the wiring pattern of the transparent electrode, and is a part completely hidden by the cover of the housing.

  As described above, by providing the notch portion in the vicinity of the key display portion of the lower substrate, the bending strength in the key display portion of the lower substrate becomes small and the bending becomes easy. For example, when a U-shaped notch is provided in the outer peripheral area of the key display portion as described above, the tension from the three directions with the notch is lost, and the tension only from one connected direction acts. Accordingly, the portion of the key display portion has a very small bending strength and is easily bent. As a result, the required deflection (amount) can be obtained with a low pressing force.

  Although the cutout portion has a U-shaped slit shape in FIG. 6, the shape of the cutout portion is not particularly limited to the U-shaped slit shape. For example, a slit may be used instead of a slit shape, and an effect of lowering the pressing force at the time of keystroke can be produced by two opposing slit shapes or four opposing slit shapes.

  As mentioned above, although embodiment of this invention was described in detail, the further detailed description of this invention is given in describing an Example below.

  Next, a key switch according to the first embodiment will be described with reference to FIG. FIG. 7 is a cross-sectional view of a main part of the key switch according to the first embodiment. In addition, the same code | symbol is provided to the component which makes the same specification as the component in the above-mentioned embodiment.

  The key switch of the first embodiment is a key switch using a liquid crystal display panel as a key display body. Compared with the key switch in the above-described embodiment, the specifications of the key display body, the pusher member, and the coating film are different, and the switch sheet has the same specification.

As shown in FIG. 7, in the structure of the key switch 52 of the first embodiment, a pusher member 70 is disposed on the back side of a key display body 60 formed of a liquid crystal display panel, and the switch sheet 40 is provided below the pusher member 70. Are arranged and covered with a coating film.
The liquid crystal display panel which is the key display body 60 is a distributed liquid crystal display panel. This dispersive liquid crystal panel is composed of a pair of substrates arranged facing each other with a certain gap, that is, a polymer material (for example, an ultraviolet curable acrylic resin) and a liquid crystal material in a gap between the upper substrate 61 and the lower substrate 62. A liquid crystal material 63 in a PNLC (Polymer Network Liquid Crystal) mode mixed with (for example, TN liquid crystal) is sealed. The upper substrate 61 has a configuration in which a transparent electrode 61b made of an ITO film is provided on the lower surface of a film substrate 61a made of a PET film, and a protective film 61c made of a polyimide resin is provided thereon, and the lower substrate 62 is made of a PET film. A transparent electrode 62b made of an ITO film formed in a matrix using TFT elements is provided on the upper surface of the film substrate 62a to be formed, and a protective film 62c made of polyimide resin is provided thereon.
Although not shown, spacer balls are disposed between the upper substrate 61 and the lower substrate 62 in which the liquid crystal material 63 is sealed, and a required cell gap is maintained.

  Here, as described in the previous embodiment, the protective films 61c and 62c provided on the transparent electrodes 61b and 62b cause breakage such as cracks in the transparent electrodes 61b and 62b due to the bending of the key display body 60. It is provided to prevent this.

The pusher member 70 has a configuration in which a pusher 72 is provided on a reflection sheet 71. The reflection sheet 71 has a reflection surface 71a on the key display body 60 side, and a pusher 72 is formed on the surface opposite to the reflection surface 71a. The reflection sheet 71 is a resin sheet on which a highly reflective metal film is formed, and a known sheet having a desired reflection color is used. The pusher 72 has the same shape as that in the above-described embodiment, that is, a spherical shape protruding in a hemispherical shape, and is formed by a screen printing method using a polycarbonate resin.
The pusher member 70 according to the first embodiment is also used as a reflection sheet of a dispersion type liquid crystal display panel which is a key display body 60, and is used by being fixed to the back surface of the key display body 60 via an adhesive. Is done.
As the key characters displayed on the key display body 60 thus configured, characters composed of white (white cloudy color) and the color tone of the reflection sheet are obtained.

  The switch seat 40 has the same configuration as that in the above-described embodiment, and the specifications of the components are the same as those in the above-described embodiment, so that detailed description thereof is omitted here.

Next, the coating film is composed of the key display body side coating film 80A and the switch sheet side coating film 80B, and is joined at the outer periphery of the key switch as shown in FIG.
The key display body side coating film 80A is made of a transparent PET film having a thickness in the range of 100 to 150 μm, and the switch sheet side coating film 80B is a hard film of SiO ₂ on the resin sheet 80B2 which is a PET film having a thickness in the range of 100 to 150 μm. The configuration is provided with 80B1. The switch sheet side coating film 80B is pasted and fixed to the FPC board 41 of the switch sheet 40 via an adhesive.

The hard film 80B1 is provided to increase the mechanical strength of the switch sheet side coating film 80B, and is preferably selected in consideration of the hardness, moisture resistance, electrical insulation, and the like. In Example 1, although SiO ₂ is selected as the material for the hard film, it is not particularly limited to SiO ₂ , and Al ₂ O _{3 and the} like can also be cited as representative materials. The hard film is preferably thickly formed, and is formed by a PVD method such as a vacuum deposition method or a sputtering method.

By making the switch sheet side coating film 80B a structure in which the hard film 80B1 of SiO ₂ is provided on the resin sheet 80B2, the bending strength of the switch sheet side coating film 80B can be increased. Further, by joining the switch sheet side coating film 80B to the FPC board 41 of the switch sheet 40, the bending strength of the FPC board 41 is greatly reinforced, the bending thereof is reduced, and the switch is easily turned on. It also increases the click rate.

In the first embodiment, a PNLC liquid crystal display panel is used as a key display, but a TN liquid crystal display panel using a general polarizing plate can also be used as a key display. However, the type using a polarizing plate is less flexible because the thickness of the display panel is increased. Therefore, it is necessary to increase the pressing force.
The PNLC-type liquid crystal display panel has a structure in which a liquid crystal material is contained in the network stitch of a resin that forms a polymer network with a three-dimensional stitch, so that deformation or alteration occurs even when a pressing force is applied by keystroke. Absent. It is a thin display panel having flexibility, and can be said to be a suitable key display body capable of maintaining quality over a long period of time.

  Next, a key switch according to the second embodiment will be described with reference to FIG. FIG. 8 is a cross-sectional view of the main part of the key switch according to the second embodiment.

  The key switch of the second embodiment is a key switch using an electroluminescence display panel (hereinafter referred to as an EL display panel) as a key display. In FIG. 8, a key switch 82 is provided with a pusher member 30 provided with a pusher 32 on an adhesive sheet 31 on the back surface of a key display body 90 formed of an EL display panel, and a switch sheet 40 provided below the pusher member 30. The key display body side coating film 100A made of a PET film and the switch sheet side coating film 100B made of a thin aluminum plate are used. And the key display body side coating film 100A and the switch sheet side coating film 100B are joined at the outer peripheral portion via an adhesive.

A key display body 90 which is an EL display panel has a structure in which an upper substrate 91, a light emitting layer 93 and a lower substrate 92 are laminated. The upper substrate 91 is provided with a transparent electrode 91b made of an ITO film formed in a matrix using a TFT element on the lower surface of a film substrate 91a made of a PET film, and a protective film 91c made of polyimide resin is formed on the transparent electrode 91b. The provided structure is made.
The lower substrate 92 is provided with a back electrode 92e made of silver paste on the upper surface of a film substrate 92a made of PET film, and an inorganic dielectric compound such as titanium oxide is dispersed on a high dielectric resin binder such as a cyanoresin compound. The dielectric layer 92f is provided.

The phosphor layer 93 is formed by dispersing phosphor powder obtained by doping a small amount of an activator (metal or halogen element) using zinc sulfide as a luminous matrix in a high dielectric resin binder such as a cyanoresin compound.
The emission color varies depending on the material of the activator to be added. For example, yellow is orange in the case of Mn, green is in the case of Tb, blue is in the case of Ce, and red is in the case of Sm.

  The EL display panel configured as described above has flexibility because a PET film having a thickness of 100 to 200 μm is used for the upper substrate 91 and the lower substrate 92, and bends when pressed with a finger or the like. Further, when a required electric field is selectively applied to the transparent electrode 91b and the back electrode 92e formed in a matrix shape, the emitted key characters are displayed.

  The pusher member 30 disposed on the back surface of the key display body 90 and the switch sheet 40 disposed below the pusher member 30 have the same specifications as the pusher member and switch sheet used in the above-described embodiment. The detailed explanation here is omitted.

The key display body side coating film 100A, which is a coating film, is composed of a transparent PET film having a thickness of 100 to 150 μm, and is provided for the purpose of moisture prevention. The switch sheet side coating film 100B, which is a coating film, is made of an aluminum plate having a thickness of about 200 μm, and is provided for the purpose of moisture prevention and for the purpose of preventing the FPC board 41 of the switch sheet 40 from being bent.
The switch sheet side coating film 100B made of an aluminum plate having a thickness of about 200 μm has rigidity, and its bending strength is several times larger than the bending strength of the FPC board of the switch sheet 40, and the switch sheet side coating film 100B. Deflection by itself is very small.

Under the above configuration, the key display body side coating film 100A made of PET film and the key display body 90, the pusher member 30, the switch sheet 40, and the switch sheet side coating film 100B made of a thin aluminum plate are overlapped. When packaged, even if the metal dome spring 43 of the switch sheet 40 is pressed by the pusher 32, the deflection of the FPC board 41 of the switch sheet 40 is restricted by the switch sheet side coating film 100B made of an aluminum plate and is kept small. It is done. Therefore, it becomes easy to switch on, and the click rate is also increased.
Moreover, although the performance of the luminescent layer 93 deteriorates due to moisture, the moisture resistance is improved by covering with the coating film having excellent moisture resistance as described above, and good quality can be maintained over a long period of time.

In addition, although Example 2 demonstrated the key display body of inorganic EL, even if it is organic EL, the same effect can be acquired.
In addition, the key display body using the EL display panel can be provided with a notch in the lower substrate as described with reference to FIG. 6 in the above-described embodiment. By providing a notch in a region outside the key display portion, the keystroke operation can be performed with a low pressing force.

  While the configuration of the key switch of the present invention has been described with reference to a mobile phone, the configuration of the key switch of the present invention can be applied not only to an electronic display device such as a PDA but also to various electronic display devices such as a car navigation system. Is. It can also be used as a touch panel itself.

It is a top view which shows an example of the key switch panel of the mobile telephone which concerns on this embodiment. It is principal part sectional drawing which showed typically the key switch in FIG. It is AA sectional drawing in FIG. It is principal part sectional drawing of the key switch mentioned as a structure which suppresses a deformation | transformation of a microcapsule. It is principal part sectional drawing of the key switch which shows the structure which can make a pressing force small. It is a principal part top view of the lower board | substrate in FIG. FIG. 3 is a cross-sectional view of a main part of the key switch according to the first embodiment. FIG. 6 is a cross-sectional view of a main part of a key switch according to a second embodiment. It is sectional drawing of the key input device shown by patent document 1. FIG.

Explanation of symbols

10 Key switch panel 11 Cover 12, 52, 82 Key switch 20, 60, 90, 120, 130 Key display body 21, 61, 91 Upper substrate 21a, 22a, 61a, 62a, 91a, 92a Film substrate 21b, 22b, 61b , 62b, 91b Transparent electrodes 21c, 22c, 61c, 62c, 91c Protective films 22, 62, 92, 132 Lower substrate 23 Microcapsule layer 23a Microcapsule 23b Adhesive 24 Sealant 30, 70 Pusher member 31 Adhesive sheet 32 72 Pusher 32a Protrusion root 40 Switch sheet 41 FPC board 42 Switch electrode pattern 43 Metal dome spring 44 Fixed sheet 50 Coating film 50A, 80A, 100A Key display body side coating film 50B, 80B, 100B Switch sheet side coating film 63 Liquid crystal material 71 Reflective sheet 8 B1 hard film 80B2 resin sheet 92e back electrode 92f dielectric layer 93 emitting material layer 125 cushioning layer 132a notch

Claims (12)

  A pusher member having a plurality of hemispherical projecting pushers is disposed on the back side of a flexible key display body having a plurality of key display portions and a variable key display, and is disposed below the pusher member. A key switch in which a switch sheet comprising a plurality of metal dome springs is provided on an FPC board, and the outer surface of the key switch has a coating film made of at least one moisture-resistant material. Key switch.   The coating film on the outer surface of the key switch comprises a key display body side coating film on the outer surface side of the key display body and a switch sheet side coating film on the outer surface side of the switch sheet. The key switch according to claim 1, wherein the sheet-side coating film is fixed to the FPC board.   The coating film on the outer surface of the key switch comprises a key display body side coating film on the outer surface side of the key display body and a switch sheet side coating film on the outer surface side of the switch sheet. The key switch according to claim 1, wherein the bending strength of the sheet-side coating film is greater than the bending strength of the FPC board.   The key switch according to claim 2 or 3, wherein the switch sheet side coating film is formed by providing a hard film on a surface of a resin sheet.   4. The key switch according to claim 2, wherein the switch sheet side coating film is made of a metal foil film or a metal plate.   The key switch according to claim 1, wherein the pusher member has a sheet shape.   2. The key switch according to claim 1, wherein the key display body is one of an electrophoretic display panel, a liquid crystal display panel, and an electroluminescence display panel.   The electrophoretic display panel includes a microcapsule layer between flexible upper and lower substrates, and a cushion layer between the microcapsule layer and the lower substrate at least in the region of the key display portion. The key switch according to claim 7, wherein the key switch is provided.   The key switch according to claim 8, wherein the cushion layer is made of a rubber-based resin.   10. The key switch according to claim 7, wherein the electrophoretic display panel has a cutout portion in the lower substrate in a region removed from the key display portion. 11.   The electroluminescence display panel includes a light emitter layer between flexible upper and lower substrates, and has a notch in the lower substrate in a region away from the key display portion. The key switch according to claim 7. An electronic display device comprising a key switch, wherein the key switch is the key switch according to any one of claims 1 to 11.

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