JP2002324453A - Decorated sheet-like key top and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a translucent sheet-like key top that is small-sized, lightweight and thin, and yet is decorated so as to present iris color glossiness by selectively reflecting light of a specific wavelength, and its easy manufacturing method that can manufacture the sheet-like key top in a short time and inexpensively. SOLUTION: In this key top a cholesteric liquid crystal layer 41 composed of a liquid crystal polymer is formed on the back face side of a key top body 21, more specifically on the back face 21b of the key top body 21. Preferably, the liquid crystal polymer is an optically active polyester containing at least one kind of hydrocarbon unit as a constituent component, selected from the group consisting of an aromatic unit, a polycyclic hydrocarbon unit and an ortho-substituted aromatic unit having a hydrocarbon of 3-8 carbon atoms and/or a halogen as a substituent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet key top used for electronic equipment such as a cellular phone, a portable information terminal, a remote controller for various home appliances, a card remote controller, and various keyboards, and a method of manufacturing the same. More specifically, the present invention relates to a sheet-like keytop decorated so as to selectively reflect light of a specific wavelength to exhibit an iris-like gloss and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, electronic devices such as portable devices, on-vehicle switches, and remote controllers have been required to be reduced in weight, size, and thickness, and push-button switches used in these devices have also been reduced in weight and size. In addition, there is a demand for a reduction in thickness.

[0003] In response to such a demand, FIG.
A sheet-like key top 50 of a push button switch as shown in FIG. The sheet-like key top 50 has a configuration in which a surface 51 a of a key top body 51 as a pressing portion made of a polymer resin is covered with a translucent resin film 61 and integrated. Then, in such a sheet-like key top 50, the front surface 51a or the rear surface 5
In many cases, a printed layer 71 formed by screen-printing characters, numerals, symbols, pictures, or the like is provided on the back surface 1a of the transparent resin film 61.

On the other hand, with the diversification of product design configurations,
There are demands for pushbutton switches of various colors and designs, for example, those in which the key top portion of the pushbutton switch is decorated to exhibit a metallic gloss or a pearl gloss.

[0005] In order to meet such a demand, a method of molding a key top body by mixing a metal powder or a pearl pigment into a polymer resin or a rubber component, and including a metal powder or a pearl pigment on the surface of the key top body. A method of providing a metal thin film layer of aluminum, chromium, etc. on the surface of the key top body by a method such as screen printing or spray coating of a paint, a vacuum evaporation method or a sputtering method, and a metal thin film layer on a surface of the key top portion by a plating method. Methods are known.

[0006]

In recent years, push-button switches used for portable telephones, portable information terminals, remote controls for various home appliances, card remote controls, various keyboards, and the like have high aesthetics and high quality. From the viewpoint of transparency, there is a strong demand for a translucent sheet-like key top that is decorated so that the key top portion exhibits an iris-like glossy tone.

However, in the above-mentioned conventional method of molding a key top body using a polymer resin or rubber mixed with a metal powder or a pearl pigment, it is difficult to uniformly disperse the powder. There is a problem that characters and symbols are difficult to see due to uneven color tone. Further, in a method of printing or painting a paint containing a metal powder or a pearl pigment on the surface of the key top body, a translucent sheet-like key top decorated so as to have a uniform and high-quality iris glossy tone. Was not obtained. Further, in a method of providing a metal thin film layer on the surface of a key top body by a vacuum evaporation method, a sputtering method, or a plating method, a translucent sheet-like key top decorated to have a metallic glossy tone can be obtained. However, a translucent sheet-like key top decorated to exhibit an iris-colored glossy tone could not be obtained.

On the other hand, the present applicant has already filed Japanese Patent Application No. 9-11 / 1997.
In Japanese Patent Application No. 1741, Japanese Patent Application No. Hei 10-73076 or Japanese Patent Application No. Hei 10-130838, means for decorating a key top portion so as to exhibit an iris glossy color is provided. That is, a transparent sheet-like key decorated by laminating a thin film of metal oxide or the like to an arbitrary thickness to selectively reflect light of a specific wavelength and to exhibit an iris-like glossy tone. It is a top and its manufacturing method. However, according to this means, a sputtering apparatus, a plating apparatus, or a complicated jig is required to form a thin film of a metal oxide or the like, so that the manufacturing process is complicated and large, and is not suitable for cost reduction. Not only that, there are disadvantages such as a long time required for the film forming work, and the method is not simple.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide an iris-colored glossy device that is small, lightweight, and thin, and selectively reflects light of a specific wavelength. It is an object of the present invention to provide a translucent sheet-like key top and a simple manufacturing method capable of manufacturing the sheet-like key top in a short time and at low cost.

[0010]

According to a first aspect of the present invention, there is provided a key top body comprising a light transmitting polymer resin and a light transmitting resin film. In a sheet-like key top in which the upper surface side is covered with a translucent resin film and integrated, a cholesteric liquid crystal layer made of a liquid crystalline polymer is provided on the back side of the key top body.

According to a second aspect of the present invention, in the first aspect of the present invention, the liquid crystalline polymer is an aromatic unit having a hydrocarbon having 3 to 8 carbon atoms and / or a halogen as a substituent. An optically active polyester comprising at least one hydrocarbon unit selected from the group consisting of a cyclic hydrocarbon unit and an ortho-substituted aromatic unit as a constituent component.

According to a third aspect of the present invention, there is provided a key top body made of a light-transmitting polymer resin and a light-transmitting resin film. In the method for manufacturing a keyed sheet-like key top, after integrating the key top body and the light-transmitting resin film, a liquid crystal polymer is applied to the back surface of the key top body and rubbed and aligned, thereby obtaining a cholesteric liquid crystal. Forming a layer.

According to a fourth aspect of the present invention, there is provided a key top body made of a light-transmitting polymer resin and a light-transmitting resin film. In the method for manufacturing a keyed sheet-like key top, after integrating the key top body and the translucent resin film, a cholesteric liquid crystal film made of a liquid crystalline polymer prepared in advance on the back surface of the key top body is bonded, A cholesteric liquid crystal layer is formed by sticking or transferring.

(Function) The present invention comprises a key top body made of a light-transmitting polymer resin and a light-transmitting resin film, and the upper surface of the key-top body is covered with the light-transmitting resin film and integrated. In the sheet-like key top, a cholesteric liquid crystal layer made of a liquid crystalline polymer is provided on the back side of the key top body. By forming a cholesteric liquid crystal layer made of a liquid crystalline polymer on the back side of the keytop body in this way, it is possible to realize a sheet-like keytop that selectively reflects light of a specific wavelength and exhibits an iris-like gloss. Can be.

The liquid crystal polymer constituting the cholesteric liquid crystal layer is not particularly limited as long as it is in a liquid crystal state showing cholesteric alignment at a high temperature and in a glass state at a temperature lower than the liquid crystal transition point. Absent.
As such a liquid crystalline polymer, for example, polyester, polyamide, polycarbonate, main chain type liquid crystalline polymer such as polyester imide, or polyacrylate,
Examples thereof include side-chain type liquid crystalline polymers such as polysiloxane. Among them, ease of synthesis, translucency,
It is preferable to use polyester as the liquid crystalline polymer from the viewpoint of orientation, glass transition point, and the like.

The liquid crystalline polymer constituting the cholesteric liquid crystal layer comprises an aromatic unit having a hydrocarbon having 3 to 8 carbon atoms and / or a halogen as a substituent, a polycyclic hydrocarbon unit, and an ortho-substituted aromatic unit. It is more preferable that the polyester is an optically active polyester containing at least one hydrocarbon unit selected from the group as a component. When the optically active polyester is used as the liquid crystalline polymer as described above, it is possible to realize a sheet-like keytop exhibiting an iris glossy tone excellent in aesthetic appearance, particularly exhibiting a uniform and high texture iris glossy tone.

The total light transmittance of the cholesteric liquid crystal layer is:
Although not particularly limited, it is preferably at least 70%. If the total light transmittance is less than 70%, the translucency becomes insufficient, visibility deteriorates, and it becomes difficult to recognize characters and symbols printed on the base. Therefore, the total light transmittance of the cholesteric liquid crystal layer is more preferably 75% or more, and particularly preferably 80% or more.

The thickness of the cholesteric liquid crystal layer is not particularly limited, but is preferably from 250 to 15000 nm, and more preferably from 500 to 5000 nm. If the film thickness is less than 250 nm, the iris gloss becomes poor, and if it exceeds 15000 nm, the translucency becomes insufficient and visibility deteriorates. Actually, depending on the material of the liquid crystalline polymer, the refractive index, the color tone, or the type, the refractive index, and the shape of the resin used for the key top body or the translucent resin film, the film thickness is 500 to 5000 nm. Highly selective reflection of light of a specific wavelength within the range, and a sheet key with excellent aesthetic appearance that exhibits a uniform and high-quality iris-colored glossy tone mainly composed of red, yellow, blue, and purple, etc. You get the top.

The cholesteric liquid crystal layer may have a configuration in which a plurality of cholesteric liquid crystal layers are stacked. When stacking in this way,
Preferably, each cholesteric liquid crystal layer has a monodomain structure with a thickness of 50 to 300 nm. Since the central wavelength of light selectively reflected by the obtained sheet-shaped keytop depends on the thickness of each layer, a sheet-like sheet with excellent aesthetic appearance that selectively reflects light of a specific wavelength and exhibits a uniform and high-quality iris-colored glossy tone. You can get a key top. The number of stacked cholesteric liquid crystal layers is preferably 5 to 50 in consideration of the selective reflectivity of light at a specific wavelength and the total film thickness.

The place where the cholesteric liquid crystal layer is formed is not limited to the back surface of the key top body, but is formed, for example, on the back surface of the sheet-like key top, that is, on the back surface of the translucent resin film around the back surface of the key top body. It does not matter. Further, the cholesteric liquid crystal layer is formed on the entire back surface of the key top body, and may be formed only on a part of the back surface of the key top body. By appropriately changing the formation location of the cholesteric liquid crystal layer, the entire surface or a part of the key top body, or the entire surface or a part of the translucent resin film selectively reflects light of a specific wavelength. Various forms of sheet-like keytops exhibiting an iris-colored glossy tone and excellent in aesthetic appearance can be realized.

The cholesteric liquid crystal layer is preferably provided with a polymer protective film made of a translucent resin and having a thickness of 5 to 60 μm on the surface. By providing the polymer protective layer on the surface of the cholesteric liquid crystal layer in this way, the liquid crystalline polymer in the cholesteric liquid crystal layer can be physically and chemically stabilized. Specific translucent resins constituting the polymer protective layer are not particularly limited, and include, for example, known translucent resins such as acrylic, urethane, silicone, epoxy and ester. Can be This polymer protective layer may be colorless, but if a chromatic color such as red, blue, or yellow is used, any color can be applied, and the color tone of the cholesteric liquid crystal layer can be further changed. When the thickness of the polymer protective layer is less than 5 μm, the mechanical properties of the polymer protective layer are weak and it is difficult to sufficiently protect the liquid crystalline polymer. On the other hand, when the thickness is more than 60 μm, the iris gloss is sharp. Fades and spoils aesthetics. More preferably, the thickness of the polymer protective layer is in the range of 10 to 40 μm. Further, a plurality of polymer protective layers may be laminated.

<Manufacturing Method> As a method of forming the cholesteric liquid crystal layer on the back surface of the key top body, various forming methods can be cited, and the forming method described in the following (1) or (2) is applied to a specific wavelength. Can be easily and inexpensively manufactured in a short time with aesthetically pleasing sheet-like key tops that exhibit a uniform and high-quality iris-colored glossy color by selectively reflecting light from the cholesteric liquid crystal layer. It can be conveniently used in that it can be easily provided.

(1) After integrating the key top body with the translucent resin film, a liquid crystal polymer is applied to the back surface of the key top body and rubbed to form a cholesteric liquid crystal polymer. A method for forming a liquid crystal layer. That is, the back surface of the key top body is subjected to a rubbing treatment, the liquid crystal polymer described above is applied to the back surface of the key top body, and then heat-treated at a temperature equal to or higher than the glass transition temperature,
Next, a cholesteric liquid crystal layer is formed on the back surface of the key top body by cooling to a temperature equal to or lower than the glass transition temperature. The application method of the liquid crystalline polymer is not particularly limited, and a known application method such as a screen printing method, a tampo printing method, a gravure printing method, a flexographic printing method, a spray coating method, a dipping method, and a potting method. Can be used.

(2) After integrating the key top body and the translucent resin film, a cholesteric liquid crystal film made of a liquid crystalline polymer previously formed on a base material is adhered to the back surface of the key top body. A method of forming a cholesteric liquid crystal layer composed of a liquid crystalline polymer by sticking or transferring. Here, the method of transferring, bonding or sticking the cholesteric liquid crystal layer is not particularly limited. For example, transfer by a hot stamp method, adhesion by an adhesive or the like, or by an adhesive or a double-sided adhesive tape or the like Examples of the method include sticking. Further, in order to produce a cholesteric liquid crystal film on a substrate, although not particularly limited, after applying the above-mentioned liquid crystalline polymer on a previously rubbed substrate, at a temperature equal to or higher than the glass transition temperature. It can be easily produced by heat treatment and then cooling to a temperature below the glass transition temperature. Further, a cholesteric liquid crystal film previously formed on a base material is placed at a predetermined position of a molding concave portion in a mold for molding a key top body, and a cholesteric liquid crystal layer is formed on the back surface of the key top body molded in the mold. Can also be applied.

Among these, the method of forming a cholesteric liquid crystal layer by transferring the cholesteric liquid crystal film by the hot stamping method described in (2) above can more easily form the cholesteric liquid crystal layer. In addition, it is preferable because it is easy to provide a cholesteric liquid crystal layer in a position-selective manner.

After the cholesteric liquid crystal layer is formed on the back side of the key top main body, a laser beam such as a YAG laser or a CO ₂ laser is swept over a part of the surface of the formed cholesteric liquid crystal layer, whereby the cholesteric alignment is performed. May be erased to form a portion having no cholesteric reflection color.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. As shown in FIG. 1, the sheet-like key top 11 of the present embodiment includes a key top body 21 as a pressing portion made of a light-transmitting polymer resin and a light-transmitting resin film 3.
1, and the upper surface 21a side of the key top main body 21 is covered with a translucent resin film 31 and integrated. That is, at least a part of the translucent resin film 31 is curved to cover a part of the key top body 21. The cholesteric liquid crystal layer 41 made of the above-mentioned liquid crystalline polymer is formed on the back side of the sheet-like key top 11, more specifically, on the back side 21 b of the key top main body 21.

The type, composition, elastic modulus, and color of the translucent polymer resin constituting the key top main body 21 are not particularly limited as long as they are translucent polymer resins. A known polymer resin such as a resin or a thermoplastic resin can be suitably used. The curing mode is not particularly limited. For example, a polymer resin in a known curing mode such as heat curing, light curing, and moisture curing can be used.

Specific translucent polymer resins constituting the key top body 21 include polymethyl methacrylate resin, polycarbonate resin, silicone resin, amorphous polyester resin, polyvinyl chloride resin, polystyrene resin, polyarylate resin, and the like. Amorphous polyolefin resin, polymethylpentene resin, amorphous nylon resin, polyurethane resin, ester-based thermoplastic elastomer, styrene-based thermoplastic elastomer, nylon-based thermoplastic elastomer, and the like are used. Can be In addition, polyethylene resin, polypropylene resin, ABS resin, crystalline polyester resin such as polyethylene terephthalate and polybutylene terephthalate, crystalline nylon resin, polyphenylene ether resin, polyacetal resin, polyacetal resin, polysulfone resin, polyethersulfone resin, polyphenylene sulfide Translucent or slightly colored translucent resin such as resin, polyimide resin, polyether resin, polyketone resin, polyetherketone resin, polyetheretherketone resin, polyethernitrile resin, polyetherimide resin, liquid crystal polymer, fluorine resin, etc. It may be a molecular resin. Further, known polymer resins such as a silicone resin, an epoxy resin, a phenol resin, an unsaturated polyester resin, a diallyl phthalate resin, an acrylic resin, and a urethane resin can also be used.

The translucent resin film 31 is not particularly limited in terms of its composition, type, elastic modulus, and color as long as it is a translucent resin film, and may be colorless transparent, colored transparent, or translucent. A known resin film having a light-transmitting property can be used. Examples of such a light-transmitting resin film include polyester, polyolefin, polystyrene, polyurethane, polyamide,
Thermoplastic films such as silicone, 1,2-polybutadiene, polyethylene vinyl acetate, polyvinyl chloride, and polyvinyl alcohol; polyamide films, polyethylene terephthalate films, polypropylene films, polycarbonate films, polyvinyl chloride films, polyvinyl alcohol films, cellophane films, and the like. These are preferably used because of their good translucency.

On the back surface 31a of the translucent resin film 31, ink or paint is applied and printed so that
A printed layer 32 on which a pattern such as a character, a number, a symbol, or a pattern is drawn is formed. The material of the ink or paint that constitutes the print layer 32 is not particularly limited, and known inks and paints can be used. From the viewpoint of adhesion and the like, acrylic resin, vinyl chloride resin, Vinyl acetate resin, vinyl chloride-vinyl acetate copolymer resin,
It is preferable to use inks or paints such as urethane resin, vinyl resin, polycarbonate resin, polyester resin, and epoxy resin. Further, the curing form is not particularly limited, for example, heat curing,
Known curing forms such as light curing and moisture curing can be appropriately selected and used.

The method for forming the print layer 32 is not particularly limited, and the back surface 31a of the light-transmitting resin film 31 to be the adhered surface is formed.
In addition, it can be easily formed by applying or printing ink or paint by a known method. For example,
A part of the back surface 31a of the translucent resin film 31 serving as an attachment surface is coated with a translucent ink or the like and drawn in a character shape, or the back surface 31a of the translucent resin film 31 serving as an attachment surface. After printing solid ink or the like having a light-shielding property on the entire surface of the substrate, the surface may be etched into a predetermined shape using a laser marker or the like, and drawn in a character shape. In order to improve the fixability, adhesion, bleeding, coloring, and the like of the ink and the paint, various known coating layers may be previously formed on the back surface 31a of the light-transmitting resin film 31 serving as the adhered surface. It is preferable that the surface is modified by performing various known surface treatments.

The method for integrating the key top main body 21 and the translucent resin film 31 is not particularly limited, and a known method can be applied. For example,
By using upper and lower dies having a molded concave portion having substantially the same shape as the desired key top main body 21, a transparent resin film 31 having a printed layer 32 formed on the front surface and / or the back surface is sandwiched between the upper and lower dies. After the mold is clamped, the heat-melted resin or the liquid uncured resin is filled into the molding recesses of the mold, so that the translucent resin film 31 is curved and the key top body 21 is molded. Body 2
1 and the translucent resin film 31 can be integrated. When the key top body 21 and the translucent resin film 31 are integrally formed as described above, the printing layer 3
In order to suppress a change in elongation, distortion, and the like of the character and shape of No. 2, it is preferable to provide a reinforcing printing layer made of a liquid resin on the printing layer 32 in advance. Examples of the liquid resin include thermosetting, photocurable, and moisture curable resins such as an acrylic resin, a urethane resin, a silicone resin, an epoxy resin, and diallyl phthalate. The reinforced print layer is formed by applying an uncured liquid resin onto the print layer 32 by using a known method such as a spray coating method, a potting method, a dispenser method, a pad printing method, a transfer method, and curing by reaction. Can be provided.

The sheet-like key top 11 obtained by integrating the key top body 21 and the translucent resin film 31 as described above has a surface, more specifically, a surface of the translucent resin film 31. It is preferable to provide an overcoat layer made of a translucent resin. By providing an overcoat layer on the surface of the translucent resin film 31,
The smoothness of the film surface is improved, the translucency or the visibility is improved, the appearance can be further improved, and the abrasion of the film surface can be prevented. Specific translucent resins constituting the overcoat layer are not particularly limited, but include, for example, known translucent resins such as acrylic resins, urethane resins, silicone resins, epoxy resins, and diallyl phthalate resins. Resin. The method for forming the overcoat layer is not particularly limited. For example, the overcoat layer can be easily formed by applying an uncured liquid resin on the surface of the light-transmitting resin film 31 and curing it by reaction. The application method of the liquid resin is not particularly limited, for example,
Spray application method, potting method, dispenser method,
A pad printing method, a transfer method and the like can be mentioned. In addition, in order to improve the adhesiveness with the translucent resin film, it is preferable that the surface of the translucent resin film 31 be subjected to a surface treatment such as short-wave ultraviolet irradiation, corona treatment, or coupling agent treatment in advance.

According to the present embodiment, the following functions and effects can be obtained. A sheet-like key including a key top body 21 made of a light-transmitting polymer resin and a light-transmitting resin film 31, wherein the upper surface 21 a side of the key-top body 21 is covered with the light-transmitting resin film 31 and integrated. On the top 11, a cholesteric liquid crystal layer 41 made of a liquid crystalline polymer was formed on the back surface side of the key top body 21, more specifically, on the back surface 21b of the key top body 21.

As a result, it is possible to realize a translucent sheet-like keytop 11 which reflects light of a specific wavelength selectively and exhibits a uniform and high-quality iris-colored glossy tone and is excellent in appearance. For example, if the cholesteric liquid crystal layer 41 has a thickness of 5
By changing the thickness in the range of 00 to 5000 nm, it is possible to realize a sheet-like keytop which is excellent in aesthetic appearance and exhibits a uniform and high-quality iris-color glossy tone mainly composed of red, yellow, blue, and purple. Further, by configuring the entire sheet-like key top 11 to have a light-transmitting property, an illuminator such as an LED (light emitting diode) or an EL (electroluminescence) can be provided to easily provide an illuminating function. it can.

The upper surface 21a of the key top main body 21
The sheet-like key top 11 in which the cholesteric liquid crystal layer 41 is provided on the side, that is, on the upper surface 21a of the key top main body 21 or the back surface 31a of the translucent resin film 31, can be realized. However, when the cholesteric liquid crystal layer 41 is provided on the upper surface 21a side of the key top main body 21 as described above, when the translucent resin film 31 is curved and deformed into the shape on the upper surface 21a side of the key top main body 21, or When the light-transmissive resin film 31 and the light-transmitting resin film 31 are integrated, there is a disadvantage that the cholesteric liquid crystal layer 41 is subjected to heat or stress and cholesteric alignment is easily disturbed.
Therefore, in order to realize a sheet-like keytop 11 having a uniform appearance and a high texture with an iris-colored gloss and excellent appearance, it is preferable to provide the cholesteric liquid crystal layer 41 on the back surface 21b side of the keytop body 21.

After the key top main body 21 and the translucent resin film 31 are integrated, a liquid crystal polymer is applied to the back surface 21b of the key top main body 21 and rubbed and aligned, so that the liquid crystal polymer is A cholesteric liquid crystal layer 41 was formed.

This makes it possible to easily and inexpensively produce a sheet-like key top 11 which reflects light of a specific wavelength selectively and exhibits a uniform and high-quality iris-colored glossy tone and which is excellent in aesthetic appearance in a short time. Can be. In addition, it becomes easy to positionally provide the cholesteric liquid crystal layer.

After the key top main body 21 and the translucent resin film 31 are integrated, a cholesteric liquid crystal film made of a liquid crystalline polymer prepared in advance is bonded and adhered to the back surface 21b of the key top main body 21. Or by transferring the cholesteric liquid crystal layer 4 made of a liquid crystalline polymer.
1 was formed.

As a result, the sheet-like key top 11 having an aesthetically pleasing iris-colored glossy tone which selectively reflects light of a specific wavelength and exhibits a uniform and high-quality iris-colored glossy tone.
Can be easily and inexpensively manufactured in a short time. In addition, it becomes easy to positionally provide the cholesteric liquid crystal layer.

[0042]

EXAMPLES Hereinafter, the embodiments will be described more specifically with reference to examples, but the present invention is not limited by these examples.

(Embodiment 1) FIG. 2 shows a cross-sectional view of the sheet-like key top 11 of this embodiment. Translucent resin film 31
A commercially available polycarbonate film having a thickness of 80 μm is used, and on the back surface 31 a of the light-transmitting resin film 31,
After forming a printing layer 32 on which characters and patterns were drawn by screen printing of a translucent ink, a reinforcing printing layer 33 was further formed on the back surface 32 a of the printing layer 32. Then, a part of the translucent resin film 31 on which the printing layer 32 and the reinforcing printing layer 33 were formed was deformed in advance to have substantially the same shape as the upper surface 21a side of the key top body 21 to be molded.

The deformed translucent resin film 31
Is clamped between upper and lower molds having a molding recess having substantially the same shape as the shape of the key top main body 21, and polycarbonate (Panlite L1225L manufactured by Teijin Chemicals Ltd.) is injected into the molding recess of the mold. Thus, the key top body 21 was molded, and the key top body 21 and the translucent resin film 31 were integrated. Next, an acrylic paint was applied to the back surface 21b of the molded key top body 21 and dried to form a base coat layer 35, and the back surface 35a of the base coat layer 35 was subjected to a rubbing treatment.

On the other hand, apart from this, 8w of a polyester-based mixed composition (logarithmic viscosity of base polymer: 0.12, Tg = 75 ° C.) as a liquid crystalline polymer represented by the following formula (A):
A t% tetrachloroethane solution was prepared.

[0046]

Embedded image An 8 wt% tetrachloroethane solution of the adjusted polyester-based mixed composition is applied to the back surface 21 b of the key top main body 21,
That is, the back surface 3 of the rubbed base coat layer 35
5a, dried and then heat-treated at 150 ° C. for 10 minutes,
Then, the cholesteric liquid crystal layer 41 is cooled to a temperature lower than the glass transition temperature, fixed, and reflects green light having a thickness of 2 μm.
Was formed. Thereafter, an acrylic printing ink was screen-printed on the back surface 41a of the formed cholesteric liquid crystal layer 41 to form a solid printing layer 43, and the sheet-like key top 11 was manufactured.

The appearance of the obtained sheet-like key top 11 is as follows.
The whole was excellent in aesthetic appearance exhibiting an iris-colored glossy color mainly composed of green. The optical spectrum of the cholesteric liquid crystal layer 41 similarly formed on a polyethylene terephthalate film having a thickness of 80 μm is shown by a solid line in FIG.

(Embodiment 2) FIG. 3 is a sectional view of a sheet-like key top 11 of this embodiment. Translucent resin film 31
A commercially available polyethylene terephthalate film having a thickness of 50 μm is used, and this translucent resin film 31 is clamped between upper and lower molds having a molding recess having substantially the same shape as the shape of the key top main body 21 and then clamped. Polycarbonate (Panlite L1225L manufactured by Teijin Chemicals Ltd.) is injected into the molding recess of the mold to form the key top body 21 and the key top body 21 and the translucent resin film 31.
And were integrated. Next, the molded key top body 2
After printing a light-shielding ink on a part of the back surface 21b of 1 by screen printing to form a printed layer 32 on which characters and patterns are drawn,
Further, a polyester-vinyl acetate adhesive was printed and cured on the back surface 32a of the print layer 32 to form an adhesive layer 44.

On the other hand, separately from this, as shown in FIG.
A hot stamp foil 46 having a cholesteric liquid crystal film 45 on a substrate 49 was produced. First, a polyethylene terephthalate film having a thickness of 12 μm was used as the base material 49, and the surface 49a of the base material 49 was subjected to a rubbing treatment. The surface 49a of the rubbed substrate 49
Then, an 8 wt% tetrachloroethane solution of the polyester-based mixed composition used in Example 1 was applied by a gravure roll method, dried, heat-treated at 150 ° C. for 10 minutes, and then cooled to a glass transition temperature or lower. To form a cholesteric liquid crystal film 45 having a thickness of 2.2 μm and reflecting red light. Further, a polymer protective layer 4 is provided on the surface 45a of the cholesteric liquid crystal film 45.
7 was formed to produce a hot stamp foil 46. The optical spectrum of the cholesteric liquid crystal film 45 of the hot stamp foil 46 is shown by a broken line in FIG.

The obtained hot stamp foil 46 is placed so that the polymer protective layer 47 faces the back surface 21b of the key top body 21, that is, the back surface 44a of the adhesive layer 44.
The polymer protective layer 47 and the cholesteric liquid crystal film 45 are transferred from the base material 49 by heating and pressing at 200 ° C. for 2 seconds using a hot stamping device, and the polymer protective layer 47 and the cholesteric A liquid crystal layer 41 was formed. After that, the cholesteric liquid crystal layer 41
Screen printing of an acrylic printing ink on the back surface 41a of
Was manufactured.

The appearance of the obtained sheet-like key top 11 is such that the key top body 21 has an iris gloss mainly composed of red, except for a portion where characters and patterns are drawn (a portion where the printed layer 32 is formed). The aesthetic appearance was excellent.

(Embodiment 3) FIG. 5 is a sectional view of a sheet-like key top 11 of this embodiment. Translucent resin film 31
A commercially available polyethylene terephthalate film having a thickness of 50 μm is used, and on the back surface 31 a of this translucent resin film 31, the characters are screen-printed with light-shielding ink, and the other portions are screen-printed with translucent ink. After forming the printing layer 32, a transparent reinforcing printing layer 33 was further formed on the back surface 32a of the printing layer 32. Then, the upper surface 2 of the key top main body 21 for molding a part of the translucent resin film 31 on which the printing layer 32 and the reinforcing printing layer 33 are formed.
It was previously deformed to the same shape as the 1a side shape.

The deformed translucent resin film 31
Is clamped between upper and lower molds having a molding recess having substantially the same shape as the shape of the key top main body 21, and polycarbonate (Panlite L1225L manufactured by Teijin Chemicals Ltd.) is injected into the molding recess of the mold. Thus, the key top body 21 was molded, and the key top body 21 and the translucent resin film 31 were integrated. Next, a polyester-vinyl acetate adhesive was printed and cured on the back surface 21b of the molded key top main body 21, thereby forming an adhesive layer 44.

On the other hand, separately from this, as shown in FIG.
A hot stamp foil 46 having a cholesteric liquid crystal film 45 on a substrate 49 was produced. First, a polyethylene terephthalate film having a thickness of 12 μm was used as the base material 49, and the surface 49a of the base material 49 was subjected to a rubbing treatment. The surface 49a of the rubbed substrate 49
Then, an 8 wt% tetrachloroethane solution of the polyester-based mixed composition used in Example 1 was applied by a gravure roll method, dried, heat-treated at 150 ° C. for 10 minutes, and then cooled to a glass transition temperature or lower. To form a cholesteric liquid crystal film 45 having a thickness of 2.0 μm and reflecting green light. Further, a polymer protective layer 4 is provided on the surface 45a of the cholesteric liquid crystal film 45.
7 was formed to produce a hot stamp foil 46.

The obtained hot stamp foil 46 is placed so that the polymer protective layer 47 faces the back surface 21b of the key top body 21, that is, the back surface 44a of the adhesive layer 44.
The polymer protective layer 47 and the cholesteric liquid crystal film 45 are transferred from the base material 49 by heating and pressing at 200 ° C. for 2 seconds using a hot stamping device, and the polymer protective layer 47 and the cholesteric A liquid crystal layer 41 was formed. After that, the cholesteric liquid crystal layer 41
Screen printing of an acrylic printing ink on the back surface 41a of
Was manufactured.

The appearance of the sheet-like key top 11 obtained is excellent in that the key top main body 21 exhibits an iris-colored glossy color mainly composed of green except for the character portion drawn with the light-shielding ink. It was.

The above embodiments and examples may be modified and implemented as follows. Changing the formation of the printing layer 32; For example, the upper surface of the translucent resin film 31 or the key top body 21
Upper surface 21a or the back surface 21b of the key top body 21
Forming the printing layer 32 on the substrate.

The technical ideas grasped from the above embodiment and examples will be described below. A sheet-like key top comprising a key top body made of a light-transmitting polymer resin and a light-transmitting resin film, wherein an upper surface side of the key-top body is covered with a light-transmitting resin film and integrated; A sheet-like key top characterized in that a cholesteric liquid crystal layer made of a liquid crystalline polymer is provided on the upper surface of the top body.

With this configuration, it is possible to realize a translucent sheet-like keytop having an aesthetic appearance, which selectively reflects light having a specific wavelength and exhibits an iris gloss. A sheet-like keytop having a key top body made of a light-transmitting polymer resin and a light-transmitting resin film, wherein an upper surface of the key-top body is covered with a light-transmitting resin film and integrated; On the back of the optical resin film,
A sheet-like key top provided with a cholesteric liquid crystal layer made of a liquid crystalline polymer.

With this configuration, it is possible to realize a translucent sheet-like keytop which is excellent in aesthetic appearance and selectively reflects light of a specific wavelength and exhibits an iris gloss.

[0061]

As described above, according to the present invention, by providing a cholesteric liquid crystal layer made of a liquid crystalline polymer on the back side of the key top body, it is small, light, thin and selectively emits light of a specific wavelength. The present invention can provide a translucent sheet-like keytop which is decorated so as to reflect light to give an iris glossy color.

Further, a light-transmitting resin film is coated on the upper surface side of the key-top main body made of a light-transmitting polymer resin to integrate them, and then a liquid crystal polymer is applied to the back surface of the key-top main body. By forming a cholesteric liquid crystal layer by rubbing alignment, a light-transmitting sheet that is small, light and thin, and is decorated so that it selectively reflects light of a specific wavelength and exhibits an iris-like gloss. It is possible to provide a simple manufacturing method capable of manufacturing a key top in a short time and at low cost.

Further, a light-transmitting resin film is coated on the upper surface side of the key-top main body made of a light-transmitting polymer resin and integrated, and then a liquid crystal polymer prepared in advance on the back surface of the key-top main body. A cholesteric liquid crystal film is formed by bonding, affixing or transferring a cholesteric liquid crystal film to form a cholesteric liquid crystal layer. It is possible to provide a simple manufacturing method capable of manufacturing a translucent sheet-like key top decorated in a short time at low cost.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a sheet-like keytop according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a sheet-like key top according to the first embodiment of the present invention.

FIG. 3 is a sectional view showing a sheet-like key top according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a hot stamp foil in Examples 2 and 3 of the present invention.

FIG. 5 is a sectional view showing a sheet-like key top according to a third embodiment of the present invention.

FIG. 6 is an optical spectrum analysis diagram of the cholesteric liquid crystal layer and the cholesteric liquid crystal film of Example 1 and Example 2 of the present invention.

FIG. 7 is a sectional view showing a conventional sheet-like key top.

[Explanation of symbols]

11: sheet key top, 21: key top body, 2
1a top surface, 21b back surface, 31 translucent resin film, 31a back surface, 41 cholesteric liquid crystal layer, 41
a: back surface, 45: cholesteric liquid crystal film.

Claims (4)

[Claims] 1. A sheet-like key top comprising a key top body made of a light-transmitting polymer resin and a light-transmitting resin film, wherein an upper surface of the key-top body is covered with a light-transmitting resin film and integrated. 3. The sheet-like keytop according to claim 1, wherein a cholesteric liquid crystal layer made of a liquid crystalline polymer is provided on a back side of the keytop body. 2. The liquid crystalline polymer is selected from the group consisting of an aromatic unit having a hydrocarbon having 3 to 8 carbon atoms and / or a halogen as a substituent, a polycyclic hydrocarbon unit, and an ortho-substituted aromatic unit. The sheet-like key top according to claim 1, wherein the key top is an optically active polyester containing at least one type of hydrocarbon unit as a constituent component. 3. A sheet-like key top comprising a key top body made of a light-transmitting polymer resin and a light-transmitting resin film, wherein an upper surface side of the key-top body is covered with a light-transmitting resin film and integrated. The method according to the above, wherein the cholesteric liquid crystal layer is formed by integrating the key top body and the translucent resin film, and then applying a liquid crystalline polymer to the back surface of the key top body and performing rubbing alignment. A method for manufacturing a sheet-like key top. 4. A sheet-like key top comprising a key top body made of a light-transmitting polymer resin and a light-transmitting resin film, wherein an upper surface of the key-top body is covered with a light-transmitting resin film and integrated. In the manufacturing method, the key top body and the translucent resin film are integrated, and then a cholesteric liquid crystal film made of a liquid crystalline polymer prepared in advance is bonded, adhered, or transferred to the back surface of the key top body. And a cholesteric liquid crystal layer is formed.