JP2004234936A - Film key sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film key sheet where the body made of resin of a key top is integrally formed with a resin film, wherein push buttons are tall and light-weight does not leak into a colored layer covering the resin film and the push button. <P>SOLUTION: There is provided a hole edge 33a of a film-removing hole, which is formed in the resin film 33, is made to rise from the surface of the resin film 33 and adhere to a peripheral face 34a of the main body of the key top 34 and the colored layer 35, which covers the resin film 33 and the body of the key top 34. As a result, without depending on the drawing workability of the resin film 33, the height of the body of the key top 34 can be set at any height, and gaps do not exist between the body of the key top 34 and the resin film 33, and poor illumination due leakage of light from the gap will not occur. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a film key sheet in which a key top body made of a thermoplastic resin and a resin film are integrated with each other, which is used for a push button switch of various devices having a key input function such as a mobile phone, a keyboard, and a controller. is there.
[0002]
[Prior art]
As shown in FIGS. 6 and 7, a push button switch of a device having a key input function includes a plurality of key top bodies 2 made of a thermoplastic resin functioning as push buttons 1, and a resin covering the surface of the key top body 2. A film key sheet 4 integrated with a film 3 is often used. The film key sheet 4 is placed on a circuit board 6 via a rubber sheet 5 made of silicone rubber or a thermoplastic elastomer. When the push button 1 is pressed toward the circuit board 6, the pusher 5a is set on a metal plate. The spring 6a is buckled to make conductive contact with a contact (not shown) on the circuit board 6 so that an input operation can be performed. If an internal light source (not shown) such as an LED is provided on the circuit board 6, a so-called illuminated film key sheet 4 illuminated by the push button 1 can be used.
[0003]
In order to manufacture the film key sheet 4, on the back surface of the resin film 3, a display portion 7 representing characters, symbols, or the like by printing or the like, or a colored layer that gives color to the push button 1 or blocks light from the LED 8 is applied in advance. Then, the resin film 3 is bent into a convex shape in the same shape as the push button 1 by drawing, and the molten resin is injected into the convex shape and solidified. Thereby, the push button 1 in which the resin film 3 and the key top main body 2 are integrated is formed.
[0004]
As such a conventional technique, for example, in Japanese Patent Application Laid-Open No. 8-156020 (Patent Document 1), a display portion is printed in advance on the surface of a resin film, and the display portion is placed in an injection molding die to display the display portion. A method of forming a key top on a part is described.
[0005]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 8-156020
[Problems to be solved by the invention]
However, among pushbutton switches used in in-vehicle electronic devices, AV devices, and the like, in order to enhance the operability by highlighting the presence of the pushbutton, the height is generally higher than that of the conventional pushbutton 1, and generally, In some cases, a high-profile push button of about 5 mm or more is required. However, in the case where the conventional push button 1 having the above-described structure is a high-profile push button, the resin film 3 must be deeply drawn deeply. Cracks may occur. Further, the resin film 3 itself may be broken due to insufficient elongation of the resin film 3. That is, since the height of the push button 1 depends on the drawability of the resin film 3, it is difficult to make the conventional push button 1 a high-profile push button by this method.
[0007]
On the other hand, as shown in FIG. 8, the key top body 12 provided with the display unit 10 and the colored layer 11 on the surface thereof is A film key sheet 15 integrated with the adhesive 14 is conceivable. However, in order to manufacture the film key sheet 15, the adhesive 14 must be uniformly and thinly applied to the entire back surface of the key top main body 12 so as not to protrude from the bonding surface. bad. Further, there is a case where the bonding area cannot be sufficiently secured, and there is a problem that the key top body 12 falls off. Since it is difficult for the film key sheet 15 to adhere the entire lower portion of the key top main body 12 to the base film 13, the film key sheet 15 is disposed between the colored layer 11 of the key top main body 12 and the colored layer 16 of the base film 13. Gaps will occur in the For this reason, when the film key sheet 15 is illuminated by the internal light source, there is a problem in that the light leaks from the gap to illuminate the film key sheet 15 differently from the colored layers 11 and 16, thereby causing a problem of poor illumination.
[0008]
Therefore, the present invention has been made in order to solve such a problem, and an object of the present invention is to make the push button tall, and to prevent light leakage from occurring in the colored layer covering the resin film and the push button. It is to obtain a film key sheet.
[0009]
[Means for Solving the Problems]
In order to achieve this object, the film key sheet of the present invention is provided with a hole edge rising from the surface of the resin film in the film removal hole formed in the resin film, and fixing the hole edge to the outer peripheral surface of the key top body, In addition, a high-profile push button provided with a colored layer covering the resin film and the key top body is provided.
[0010]
The high-profile push button provided on the film key sheet of the present invention has a hole edge portion of the resin film fixed to the outer peripheral surface of the key top body. Therefore, unlike the conventional film key sheet (4), the resin film (3) covering the entire surface of the push button (1) can be eliminated, so that the back of the key top main body is not dependent on the drawing workability of the resin film. Can be of any height. In addition, since the high-profile push button is provided with a colored layer that covers the resin film and the key top body, the colored layer is a series without being divided by the resin film and the key top. Therefore, when this is an illuminated type, unlike a conventional film key sheet (15) in which illumination is defective due to light leakage in a gap between the divided colored layer (11) and the colored layer (16), the key is different. A structure in which illumination failure due to light leakage in the divided gap between the top body and the resin film does not occur.
[0011]
Further, in this film key sheet, since the coloring layer is formed so as to cover the key top body and the resin film, if the coloring layer is formed of a light-shielding material, light transmission can be blocked, and If the layer is formed of a translucent material, it can be illuminated from the entire surface of the push button, so that it can be applied to diversification of designs. In addition, since the coloring layer is provided on the surface of the film key sheet, the coloring layer can be easily formed, and the film key sheet can be easily decorated.
[0012]
In the film key sheet of the present invention, a display portion for displaying characters, symbols, and the like on the colored layer can be formed. Since the coloring layer covers the key top body and the resin film, the display unit is formed on the surface of the film key sheet, and is not formed inside the resin film or the key top body. A display portion with good visibility can be obtained. That is, since the display section is not formed on the back surface of the key top main body, it is necessary to visually recognize the display section through the thick high-profile push button even with a film key sheet having a tall high-profile push button. And the display portion can be clearly seen.
[0013]
Furthermore, in the case of the film key sheet of the present invention, if a lightening portion is provided on the back surface of the key top body, the occurrence of sink marks can be avoided even when the height of the key top body is raised, and the high height type push button is distorted. And a film key sheet without dents. Further, the weight reduction of the film key sheet can be achieved by the lightening portion.
[0014]
The film key sheet of the present invention can be a so-called illuminated film key sheet by forming the key top body of a light-transmitting resin and forming the coloring layer as a light-transmitting coloring layer. Since the key top body is not covered with the resin film, the film key sheet can be a film key sheet having high transparency and excellent design.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the film key sheet of the present invention will be described in more detail with reference to the drawings. FIG. 1 is a partial sectional view showing one embodiment of the film key sheet 31 of the present invention. Although only one high-profile push button 32 is shown in FIG. 1, usually, a plurality of such push buttons 32 are formed on the resin film 33 as shown in FIG.
[0016]
The film key sheet 31 is formed by integrally forming a resin film 33 and a high-profile key top body 34. At the corresponding position of the resin film 33 where the push button 32 is formed, a hole edge 33a rising upward from the surface is formed. The key top body 34 is integrally fixed to the hole edge 33a by heat fusion, and the side surface 34a is substantially flush with the outer peripheral surface 33b of the hole edge 33a. Therefore, since the edge 33c of the hole edge 33a does not protrude from the side surface 34a of the key top main body 34, the hole edge 33a does not catch on the hole edge provided in the housing. Further, a lightening portion 34c is formed on the back surface 34b of the key top main body 34 so that the high-top key top main body 34 does not have sink marks.
[0017]
On the surfaces of the resin film 33 and the key top body 34, a colored layer 35 that covers the entire film key sheet 31 is provided. In addition, on the upper surface (top surface) of the key top main body 34, the coloring layer 35 is cut out in a cut-out character shape to form the display section 36.
[0018]
In this film key sheet 31, a key top main body 34 forming a high-profile push button 32 and a resin film 33 are widely fixed on an inner peripheral surface 33d of a hole edge 33a. Therefore, a strong adhesive force is exerted in the operation direction (up and down direction) of the push button 32. Therefore, even if the push button 32 is repeatedly pressed, the boundary portion 37 between the resin film 33 and the key top main body 34 is not easily peeled off. Therefore, the coloring layer 35 formed on the boundary portion 37 is hardly cracked or peeled off.
[0019]
Also, unlike the conventional film key sheet 4 in which the upper surface of the key top body 2 is covered with the resin film 3 and the display section 7 is formed on the back surface of the resin film 3, the resin film 33 is formed of the key top body 34. Since the upper surface of the display portion is not covered, the display portion is not visually recognized through the resin film, and a clear display portion 36 is obtained.
[0020]
Next, one embodiment of a method of manufacturing the film key sheet 31 will be described.
[0021]
First, a step of forming a film removing hole at a position corresponding to the push button 32 of the resin film 33 is performed by a press molding machine. At this time, the film removal hole obtained by piercing the resin film 33 has a size slightly smaller than the outer diameter of the push button 32. Subsequently, draw forming in the vicinity of the film removing hole is performed by a press forming machine. That is, a hole edge 33a that rises upward from the surface of the horizontal resin film 33 is formed from the film removal hole formed at a position corresponding to the push button 32.
[0022]
Then, the injection molding process of the key top body 34 is executed. The drawn resin film 33 is placed and placed on a first mold in which a cavity corresponding to the shape of the push button 32 is formed such that the outer peripheral surface 33b of the hole edge 33a faces the surface forming the cavity. The second mold having a flat surface facing the resin film 33 is overlaid. Then, the molten resin is injected from the pin gate of the second mold, and flows into the cavity through the inner peripheral surface 33d of the hole edge 33a. At this time, due to the flow pressure of the molten resin, the hole edge 33a of the resin film 33 comes into contact with the surface forming the cavity, and the molten resin does not flow around the outer peripheral surface 33b of the hole edge 33a. When the cavity is filled with the molten resin, excess resin flows into the air vent in the second mold. Thereafter, the molten resin is cured, the first mold and the second mold are opened, and the film key sheet 31 is taken out.
[0023]
In the process from the injection of the molten resin to the solidification thereof, the inner peripheral surface 33d and the edge 33c of the hole edge 33a of the resin film 33 and the key top main body 34 are fixed by heat fusion. Therefore, the key top main body 34 of this embodiment is integrated with the resin film 33, and has a fixing force that can withstand practical use.
[0024]
With respect to the film key sheet 31 having undergone the above-described injection molding step, a step of forming a colored layer 35 having a light-shielding property and giving a color is performed on the surface of the film key sheet 31 by a method such as painting or printing. Thereafter, the colored layer 35 of the push button 32 is cut out by laser processing or the like and cut into a character shape to form a display portion 36 representing characters, symbols, and the like. Then, a gate cut or the like is performed to remove an unnecessary portion to obtain a completed film key sheet 31.
[0025]
Next, each part of the film key sheet 31 will be described.
[0026]
A plurality of push buttons 32 are formed on the resin film 33 which is a part of the film key sheet 31, but the push operation of one push button 32 has elasticity such that it does not interlock with the push operation of the other push buttons 32. is there. The resin film 33 functions to prevent light leakage between the push buttons 32 and to prevent moisture and dust from entering the inside of the device.
[0027]
The material used for the resin film 33 is preferably a polycarbonate resin, an ABS resin, an acrylic resin, a polyester resin, a polyamide resin, a PBT resin, or an alloy thereof in consideration of moldability, fixability to the key top body 34, and the like. . When used as the illuminated film key sheet 31, it is preferable to use a translucent resin film. In addition, a resin film having high dimensional stability is preferable to be integrated with the key top body 34.
[0028]
The thickness of the resin film 33 is determined in consideration of moldability at the time of integration with the key top body 34, operability as a push button switch, functionality, durability, and the like, and is usually 25 μm to 200 μm, preferably, It is 50 μm to 150 μm.
[0029]
The material used for the key top main body 34 is appropriately selected from silicone rubber, thermoplastic elastomer, thermosetting resin, thermoplastic resin, and the like. Consideration is given to moldability, transparency, adhesion to the resin film 33, and the like. Then, a thermoplastic resin is preferable. Particularly, a polycarbonate resin, an ABS resin, an acrylic resin, a polyester resin, a PBT resin, and an alloy thereof are preferable. In the case of an illuminated type, it is preferable to use a translucent resin, and it is more preferable to use a colorless and transparent resin.However, depending on the application, colored transparent or colored or colorless translucent, colored opaque Those can also be used.
[0030]
It is also important to determine the combination of the key top body 34 and the resin film 33. It is preferable that the material of the key top body 34 and the material of the resin film 33 be the same or of the same type, since the fixing force between them is increased and the durability is improved. In that sense, it is preferable that both the combination of the resin film 33 and the key top body 34 be a polycarbonate resin. As other combinations, for example, an alloy film of polycarbonate and polybutylene terephthalate and a polycarbonate resin, a polycarbonate film and an acrylonitrile-butadiene-styrene resin, and an acrylic film and an acrylic resin can be used.
[0031]
Further, a compounding agent for improving the adhesion to the resin film 33 may be added to the key top main body 34, or conversely, before applying an adhesive or the like for improving the adhesion to the resin film 33. The processing may be performed in advance. In addition, it is a matter of course that addition of a compounding agent and various pretreatments may be performed in order to improve moldability and the like.
[0032]
The display unit 36 is a part that displays characters, symbols, and the like. In the present embodiment, the colored layer 35 on the upper surface of the push button 32 is cut out in a cut-out character shape, and the key top main body 34 is exposed to form the display section 36.
[0033]
The coloring layer 35 is a layer formed to give color to the film key sheet 31 and to shield light from the LED. Therefore, the coloring layer 35 can be formed according to various usage modes of the film key sheet 31. For example, the coloring layer 35 may be light-transmitting (light-transmitting) instead of light-shielding. If it is light-shielding, it can be an illuminated film key sheet 31 in which only the portion without the colored layer 35 illuminates the illumination from an LED or the like provided below the film key sheet 31. As a result, a film key sheet 31 of a type in which the entire surface of the push button 32 shines in a predetermined color can be obtained.
[0034]
For the colored layer 35, use is made of a non-crosslinkable resin such as a solvent evaporation type, or an ink or paint formed from a crosslinkable resin such as a heat curable type, an ultraviolet curable type, a moisture curable type, or an electron beam curable type. Can be. This is because the adhesiveness to the resin film 33 and the key top body 34 is good, and the workability is also preferable. Above all, from the viewpoint of excellent workability when unnecessary portions are removed by laser processing for forming the display portion 36, urethane-curable inks such as acrylic urethane and polyester urethane and acrylic silicone inks and paints are used. It is more preferable to use. Further, from the viewpoint of workability and adhesion to the key top body 34, it is more preferable to use an ink or paint made of a solvent-evaporable, non-crosslinkable resin such as a vinyl-based, acrylic-PC-based, or polycarbonate-based resin. Further, the colored layer 35 can be formed not only from a resin ink but also as a vapor-deposited layer, formed by transferring a metal thin film or the like, or can be formed as a plating layer. Then, two or more layers having different colors and materials may be laminated. Therefore, the colored layer 35 can be formed by various methods including a printing method such as screen printing and pad printing, a coating method, and a potting and dipping method.
[0035]
In the film key sheet of the present invention, various decorations can be given on the film key sheet depending on how the colored layer and the display section are provided. For example, as in the case of the film key sheet 38 shown in FIG. 2, the colored layer 39 may be provided with colored translucent ink, and the display unit 40 may be provided in a character shape with colored light-shielding ink. In addition, as in the film key sheet 41 shown in FIG. 3, an auxiliary coloring layer 43 having a different color from the coloring layer 42 is formed in advance with a coloring translucent ink or the like under the coloring light shielding coloring layer 42. Can be. If the coloring layer 42 is cut out and cut into a character shape, the auxiliary coloring layer 43 appears in the character shape, so that the display unit 44 can be realized with various character colors, and the film key sheet 41 with excellent design can be obtained. For the auxiliary coloring layer 43, the same ink or paint as that of the coloring layer 42 can be used. The display section 44 can also be formed by previously masking the auxiliary colored layer 43 in a character shape with a transparent resin and then applying the colored layer 42.
[0036]
A protective layer can be further provided as shown in FIGS. 4 and 5 so that the coloring layer and the display portion are not worn or stained. The film key sheet 51 shown in FIG. 4 is obtained by providing a protective layer 52 on the film key sheet 31 shown in FIG. The film key sheet 55 shown in FIG. 5 is obtained by providing a protective layer 56 on the film key sheet 41 shown in FIG. The material of the protective layers 52 and 56 is preferably a material having good adhesiveness to the colored layers 35 and 42 and the auxiliary colored layer 43, abrasion resistance, and workability such as painting and printing. A crosslinkable resin such as a curable type, a moisture-curable type, and an electron beam-curable type is preferable. In particular, it is preferable to use urethane curable such as acrylic urethane type or polyester urethane type or an acrylic type ink or paint. The method for forming the protective layers 52 and 56 can be selected in the same manner as the method for forming the colored layers 35 and 42.
[0037]
Note that the above embodiment is an example of the present invention, and the present invention includes various modifications made by those skilled in the art without departing from the spirit thereof.
[0038]
For example, in the above embodiment, the hole edge 33a is fixed to the lower end of the side surface 34a of the key top main body 34, but the hole edge 33a is raised and fixed so as to cover the side surface 34a to a position near the upper end. You may make it. However, when the entire surface of the push button 32 is illuminated, if the stand is raised too long, the amount of light illuminated from the side surface 34a is reduced, and there is a disadvantage that the outer periphery of the push button 32 is not clearly distinguished. It is preferable to fix to the lower end of the side surface 34a of the key top main body 34 as in the embodiment.
[0039]
Note that the method of manufacturing the film key sheet described in the above embodiment is also an example. For example, a resin film having an opening formed in advance may be used without performing a step of forming a film removing hole. .
[0040]
【The invention's effect】
According to the film key sheet of the present invention, the key top main body can be firmly fixed to the resin film even if the resin film that has been conventionally fixed to the top and bottom surfaces of the key top main body is eliminated. Since it is not affected by the characteristics, a film key sheet having a high-profile push button can be realized.
[0041]
According to the film key sheet of the present invention, the display portion is formed on the surface of the high-profile push button, and the display portion is not visually recognized through the thick key top body. Since the display unit is not visually recognized through the display unit, sufficiently clear visibility can be obtained for the display unit.
[0042]
In addition, according to the film key sheet of the present invention, by forming a flesh relief portion on the back surface of the key top main body, sink does not occur on the surface of the key top main body even with a high-profile push button, further reducing the weight of the film key sheet. I can do it.
[0043]
Furthermore, according to the film key sheet of the present invention, since the resin film reaches only a part of the push button, it is easy to produce a film key sheet having a push button having a complicated shape.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view of a film key sheet according to an embodiment of the present invention.
FIG. 2 is a partial cross-sectional view of a film key sheet according to another embodiment of the present invention.
FIG. 3 is a partial cross-sectional view of a film key sheet according to still another embodiment of the present invention.
FIG. 4 is a partial cross-sectional view of a film key sheet according to still another embodiment of the present invention.
FIG. 5 is a partial cross-sectional view of a film key sheet according to still another embodiment of the present invention.
FIG. 6 is a schematic perspective view of a conventional film key sheet.
FIG. 7 is a partial cross-sectional view showing an installation state of a conventional film key sheet, and is a cross-sectional view taken along line SA-SA of FIG.
FIG. 8 is a partial sectional view of another conventional film key sheet.
[Explanation of symbols]
1,32 push button 2,12,34 key top body 3,33 resin film 33a hole edge 33b outer peripheral surface 33c edge 33d inner peripheral surface 4,15,31,38,41,51,55 film key sheet 5 rubber Sheet 5a Presser 6 Circuit board 6a Metal disc springs 7, 10, 36, 40, 44 Display sections 8, 11, 16, 35, 39, 42 Color layer 13 Base film 14 Adhesive 37 Boundary portion 43 Auxiliary color layer 52 , 56 protective layer

Claims (4)

In a film key sheet in which a resin key top body is integrally formed with a resin film,
A high-profile push button provided with a colored layer that covers the resin film and the key top body by raising the edge of the film removal hole formed in the resin film from the surface of the resin film and fixing it to the outer peripheral surface of the key top body. Having a film key sheet. The film key sheet according to claim 1, wherein a display portion for displaying characters, symbols, and the like is formed on the colored layer. The film key sheet according to claim 1 or 2, wherein a lightened portion is formed on the back surface of the key top body. The film key sheet according to any one of claims 1 to 3, wherein the key top body is made of a translucent resin, and the colored layer is formed as a translucent colored layer.

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