JP2005259544A - El sheet and lighted push-button switch member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an EL sheet and a lighted push-button switch member in which occurrence of lighting failure trouble or the like is less at an EL element even if it is worked to have a three-dimensional shape by a plastic working or the like, and in which light emission is enabled stably for a long time. <P>SOLUTION: An EL laminate sheet including a counter electrode layer 14, a dielectric material layer 13, a light emitting layer 12, and a transparent electrode layer 10 is formed. A conductive polymer is used for the transparent electrode layer 10, and a binder high in adhesiveness to the conductive polymer is used for the light emitting layer 12. As the binder high in the adhesiveness, polyester, acrylate, cyanoacrylate, polyolefin, ethylene-vinyl acetate or ethylene-ethyl acrylate based adhesive is used. The dielectric layer is formed by a fluoro-resin binder. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is, for example, a mobile communication device such as a mobile phone or a PDA, a CD player, an MD player, a small tape recorder, or a member for an illuminated pushbutton switch of a small electric / electronic device mounted on an automobile, or an EL sheet used therefor About.

  Conventionally, an illumination type pushbutton switch is used in an input device such as a mobile communication device. In this type of illumination type push button switch member, a so-called illumination function for illuminating a display portion showing the function of the push button switch is required at nighttime use.

  FIG. 2 shows an example of a conventional illuminated pushbutton switch. For example, in a conventional pushbutton switch 30 used for an input device such as a cellular phone, as shown in FIG. 2, a cover base 32 formed integrally with a plurality of key top portions 31 constituting operation keys, and a circuit The switch 33 is incorporated in the casing of the target input device in a state of facing the substrate 33 so that the switch function of the push button switch 30 can be realized. The push button switch 30 has a display unit 34.

  On the circuit board 33, a light source such as an LED 35 is provided. The light emitted from the light source or the reflected light is transmitted from the back surface portion of the key top portion 31 to the top surface portion, so that a mobile phone or the like can be used without any trouble even at night.

  This applicant has already made a patent regarding a pushbutton switch member and a method for manufacturing the same, which can illuminate the display unit without unevenness in luminance while suppressing power consumption by incorporating an EL element using an electroluminescent material. An application has been filed (Patent Document 1).

Further, the key top portion main body is formed of a light transmissive resin film, and a transparent electrode layer which is an organic polymer layer is provided on the lower surface of the resin film. Further, an auxiliary electrode layer, a light emitting layer, a dielectric There is also known an illuminated sheet-like key top configured to include a layer, a counter electrode layer, and an insulating layer (Patent Document 2).
JP 2002-367469 A JP 2000-285760 A

  An EL element used for a pushbutton switch member is composed of a transparent electrode layer, a light emitting layer, a dielectric layer, and a counter electrode layer. In general, a thin film of indium oxide-tin oxide (ITO) is formed on the transparent electrode layer. used. However, since the ITO thin film is glassy, it is easy to break when a certain amount of elongation stress is applied, etc., and the formability of the three-dimensional shape is poor. However, a pushbutton switch member such as a mobile phone is a complicated three-dimensional member. Often shape is required. Therefore, when a three-dimensional shape is formed by drawing, a conductive polymer that is difficult to break against elongation stress is used as the transparent electrode layer.

  However, since the conductive polymer has poor adhesiveness, when the three-dimensional shape is formed by drawing, the remaining stress acts in the direction of peeling from the interface of each layer. For example, the transparent electrode layer and the light emitting layer having low adhesion In some cases, the EL element was peeled off, and this caused a partial failure of the EL element.

  In addition, the light emitting layer and dielectric layer may use a cyanoethyl binder with good adhesion, but the cyanoethyl binder has a hygroscopic property, so the light emitting layer and the dielectric layer generate non-lighting and black spots due to moisture absorption. Sometimes. A black spot means a color change caused by a short circuit that occurs in a dielectric layer, a light emitting layer, a transparent electrode layer, or the like. This is considered to be caused by impurity ions contained in each layer.

  Therefore, the present invention provides an EL sheet that can emit light stably and stably for a long period of time, even if it is processed into a three-dimensional shape such as drawing, for example, and there is little non-lighting or black spots on the EL element. An object is to provide a member for an illuminated pushbutton switch.

  In order to solve the above-described problems, the invention according to claim 1 is an EL sheet including a counter electrode layer, a dielectric layer, a light emitting layer, a conductive polymer transparent electrode layer, and a sheet base material. The binder is characterized in that it is different from the binder for the dielectric layer and has high adhesion to the conductive polymer.

  In addition to the structure of Claim 1, the invention described in claim 2 is a light-transmitting material having high adhesiveness between the conductive polymer transparent electrode layer and the sheet base material and the conductive polymer. It is characterized by interposing an adhesive layer.

  In addition to the structure of Claim 1 or 2, the light-emitting layer binder is one or more selected from the group consisting of polyester, acrylic, cyanoacrylate, and ethylene vinyl acetate. It is characterized in that it is a resin-based binder or a synthetic rubber-based binder represented by urethane.

  According to a fourth aspect of the present invention, in addition to the structure according to any one of the first to third aspects, the dielectric layer uses a fluororesin binder as a binder.

  According to a fifth aspect of the present invention, in addition to the structure according to any one of the first to third aspects, the counter electrode layer, the dielectric layer, the light emitting layer, the conductive polymer transparent electrode layer, and the conductive polymer At least one of the translucent adhesives having high adhesiveness is characterized by being formed by dispersing ion exchangers.

  The invention according to claim 6 uses the EL sheet according to any one of claims 1 to 5, and protrudes a convex portion from the back side where the counter electrode layer is close to the front side where the transparent electrode layer is close, and on the back side of the convex portion. Is characterized in that it is filled with at least a core material corresponding to the key top shape.

  In the invention according to the first aspect, since the binder having high adhesiveness with the conductive polymer is used for the light emitting layer, the bond between the transparent electrode layer and the light emitting layer becomes strong.

  In the invention according to the second aspect, since the binder having high adhesiveness with the conductive polymer is used for the sheet base material, the bond between the transparent electrode layer and the sheet base material becomes strong.

  In the invention according to claim 3, the transparent electrode layer and the light emitting layer or the sheet substrate are firmly bonded with a binder having high adhesiveness to the conductive polymer.

  In the invention described in claim 4, since the binder uses a fluororesin binder having a low saturated moisture absorption rate and a hydrophobic property, the dielectric layer is difficult to absorb moisture even in a high humidity environment. Even so, the dielectric degradation is low and dielectric breakdown is unlikely to occur.

  In the invention described in claim 5, since the ion exchanger has a property of selectively capturing free ions, partial non-lighting and black spots are generated by suppressing deterioration of insulation resistance and suppressing electrochemical reaction in a hygroscopic state. Etc., and reliability is improved and life is improved.

  A sixth aspect of the present invention is an illumination type push button switch member, and has the function of the first aspect of the present invention.

  According to these inventions, for example, even when processed into a three-dimensional shape body such as drawing, there is little generation of non-lighting and black spots, etc., and a highly moisture-resistant EL provided with an EL element that can stably emit light for a long period of time. Can provide a sheet. In addition, such an illumination type push button switch member can be provided.

  In particular, the invention described in claims 1 to 3 has a strong bond between the transparent electrode layer and the light emitting layer and / or the sheet substrate, and even if various stresses during molding act, delamination and increase in resistance value are caused. It is possible to prevent uneven light emission and non-lighting since it is suppressed.

  The invention according to claim 4 makes it difficult for the dielectric layer and the surrounding binder to absorb moisture, and can suppress an electrochemical reaction related to insulation deterioration, migration, decomposition, bonding, or the like. Therefore, an EL sheet excellent in environment resistance and long-term lighting life can be obtained.

  In the invention according to claim 5, in the case of an ion exchanger, there is a property of selectively capturing ions. Therefore, even when ions are generated in an EL element, electrochemistry related to insulation deterioration, migration, decomposition, bonding, etc. Since the reaction is suppressed, an EL sheet excellent in environment resistance and long lighting life can be obtained.

  According to the sixth aspect of the present invention, an illuminated pushbutton switch member having the effects of the first to fifth aspects can be obtained.

  FIG. 1 is a cross-sectional view of an essential part of a switch using an illuminated pushbutton switch member 1 according to the preferred embodiment of the present invention.

  The illuminated pushbutton switch member 1 according to the embodiment shown in FIG. 1 includes an EL sheet 2 and a core material 3. The back surface of the EL sheet 2 is filled with the core material 3 to form the key top portion 4. The key top portion 4 is provided with a light emitting portion 5 on the top surface portion formed by the EL sheet 2.

  The illuminated pushbutton switch member 1 is provided above the circuit board 6. The circuit board 6 has a pair of fixed contacts 7, and a dome-shaped metal disc spring 8 is often provided so as to cover the pair of fixed contacts 7. A pressing projection 9 is provided at the lower end of the key top portion 4. The pressing protrusion 9 presses the disc spring 8 when the key top portion 4 is pressed toward the circuit board 6, and the pair of fixed contacts 7 are closed.

  For the key top portion 4, a cover base made of an elastic material such as silicone rubber may be used as necessary. The cover base material has elasticity and can be waterproofed by sealing at the outer periphery.

  The outermost peripheral surface of the key top portion 4 is formed of a transparent insulating film 10. A transparent electrode layer 11 for forming one electrode is provided on the back surface of the transparent insulating film 10. The back surface of the transparent electrode layer 11 is combined with the light emitting layer 12. The light emitting layer 12 is provided only on the light emitting portion 5 of the key top portion 4.

  A dielectric layer 13 is provided on the back surface of the light emitting layer 12. Further, a counter electrode layer 14 for forming the other electrode is provided on the back surface of the dielectric layer 13. The transparent electrode layer 11, the light emitting layer 12, the dielectric layer 13 and the counter electrode layer 14 form the light emitting portion 5. In addition, outside the light emitting portion 5, the back surface of the transparent electrode layer 11 is combined with the dielectric layer 13.

  The EL sheet 2 is provided with a film adhesive layer 15 on the back surface of the counter electrode layer 14 constituting the light emitting unit 5. The EL sheet 2 is provided with a convex portion from the counter electrode layer 14 side on which the film adhesive layer 15 is provided toward the transparent electrode layer 12 side on which the transparent insulating film 10 is provided, and the core material 3 is provided on the back side of the convex portion. Filled to form an illuminated pushbutton switch member 1.

  As the transparent insulating film 10 on the outer peripheral surface of the key top portion 4, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polystyrene, polyimide, polyamide, polyphenyl sulfide, or the like, or an acrylic resin can be used. These may be homopolymers or copolymers. Moreover, modified | denatured materials, such as an alloy, may be sufficient. Not only resins, but also styrene, polyester, and polyamide thermoplastic elastomers can be used. As thickness of the transparent insulating film 10, 10-500 micrometers is suitable. The most preferable example is a polycarbonate alloy film having a thickness of 100 to 300 μm.

  A transparent conductive polymer is used for the transparent electrode layer 11 on the back surface of the transparent insulating film 10. As the conductive polymer, polypyrrole, polythiophene, polyaniline, or derivatives thereof are preferable. These are preferable because they have transparency and high conductivity.

  Further, by providing an adhesive layer with high translucency between the transparent insulating film 10 and the transparent electrode layer 11, the reliability of adhesion is improved. As the adhesive layer, a binder having adhesiveness to the transparent electrode layer may be provided. Specifically, polyester-based, acrylic-based, cyanoacrylate, polyolefin, ethylene vinyl acetate, ethylene ethyl acrylate-based resin or Examples include copolymers, and synthetic rubbers such as urethane rubber and butyl rubber.

  The transparent electrode layer 11 is formed of a conductive paint such as carbon or nickel, a low resistance conductive paint such as silver, or an auxiliary electrode made of metal foil, if necessary, in addition to the conductive polymer, in a portion that does not require transparency. May be.

  The light emitting layer 12 provided on the back surface of the transparent electrode layer 11 uses an adhesive having high adhesion to the conductive polymer as a binder. This is different from the binder used for the dielectric layer 13. Examples of such an adhesive binder include polyester, cyanoacrylate, ethylene vinyl acetate, and acrylic resins. These may be homopolymers or copolymers. Also, synthetic rubber such as urethane rubber and butyl rubber may be used. These may be used alone or in combination of two or more.

  As the light emitting layer 12, an EL phosphor that is moisture-proof coated with a thin film of aluminum oxide, titanium oxide, silicon oxide or the like is dispersed in a binder, and the thickness is preferably 0.5 to 50 μm.

  The dielectric layer 13 provided on the back surface of the light emitting layer 12 increases luminous efficiency by dispersing a high dielectric such as barium titanate, titanium oxide or potassium titanate in a binder. The binder is preferably a cyanoethylated product typified by cellulose. Other examples include fluorine resins, polyester resins, and acrylic resins. These may be homopolymers or copolymers. Synthetic rubber may also be used. Preferably, a material having a dielectric constant as high as possible is selected. Of these, the fluororesin binder is preferable because of its excellent hydrophobicity.

  The counter electrode layer 14 provided on the back surface of the dielectric layer 13 may be formed of a conductive paint in which a conductive filler is dispersed in an insulating resin solution. The conductive filler may be a single metal such as gold, silver, copper, or nickel, or may be an alloy containing these single metals. In addition to metals, carbon black, graphite and the like can also be mentioned. Examples of the resin solution include an epoxy resin, a urethane resin, an acrylic resin, a polyester resin, and a silicone resin. These may be homopolymers or copolymers. It may be used alone or in combination of two or more.

  An ion exchanger may be dispersed together in at least one of the light emitting layer 12 and the dielectric layer 13. In particular, when a cyanoethyl-based binder is used as the binder, the ion exchanger captures ions in the layer and effectively blocks unexpected movement of ions.

  There are ion exchangers for positive ions, negative ions, and both ions. For cation or for both ions is desirable. Examples of ion exchangers that can be preferably used include zirconium, antimony, and bismuth.

  The introduction amount of the ion exchanger is calculated for each layer, and is 0.1 to 15% by mass, preferably 1 to 10% by mass in the amount including the binder. If the amount is 1% by mass or less, a sufficient ion trapping effect may not be obtained. If the amount exceeds 10% by mass, the dielectric constant of the layer starts to decrease, which is not preferable.

  A film adhesive layer 15 is provided on the back surface of the surface light emitter 5 formed by the transparent electrode layer 11, the light emitting layer 12, the dielectric layer 13, and the counter electrode layer 14. As the film adhesive layer 15, a resin or rubber may be used. The film adhesive layer 15 is useful for enhancing the adhesiveness with the resin that becomes the core material 3.

  The material of the core 3 of the key top portion 4 may be a hard or soft resin, an elastomer, a silicone rubber, or the like. Either thermoplastic or thermosetting may be used. Specifically, for example, polycarbonate resin or the like is used.

  The core material 3 is formed in a substantially cylindrical shape, for example. Or you may form with the elliptical column or the prism.

  For example, colored ink may be partially applied between the back surface of the transparent insulating film 10 and the transparent electrode layer 11. If a colored ink is used, a desired colored pattern can be provided.

  The illuminated pushbutton switch member 1 as described above is manufactured, for example, as follows.

  Using a printing machine, for example, the transparent insulating film 10 placed horizontally is placed at the bottom, and a strip-shaped transparent electrode layer 11 is formed thereon by, for example, screen printing. The transparent electrode layer 11 is formed to have a width substantially equal to the width of the top surface of the key top portion 3 and is aligned with the position where the key top portion 3 of the transparent insulating film 10 is located.

  A light emitting layer 12 is formed on the transparent electrode layer 11 at a place where light emission is necessary, for example, by screen printing. The light emitting layer 12 uses light emitting ink or the like.

  A dielectric layer 13 is applied on the light emitting layer 12, and a counter electrode layer 14 having the same size as the light emitting layer 12 is printed thereon. A film adhesive layer 15 is printed on the counter electrode layer 14. In this way, the EL sheet 2 is obtained.

  The obtained EL sheet 2 is fitted into a predetermined cavity. It sets in the uneven | corrugated metal mold | die formed according to the shape of the desired key top part 4, and performs a drawing process by pressure-air and vacuum forming or compression molding. The transparent insulating film 10 side is protruded and a recess is provided on the film adhesive layer 15 side. The formed recess is filled with a core material 22 such as polycarbonate resin. In this way, the illuminated pushbutton switch member 1 is obtained in which delamination between the transparent electrode layer 11 and the light emitting layer 12 hardly occurs.

  Examples will be described below.

  According to the above embodiment, the EL sheet 2 and the illuminated pushbutton switch member 1 were formed as follows.

  Byhole (trade name, manufactured by Bayer), which is a 125 μm polycarbonate alloy film, was prepared as a transparent insulating film 10 on the outermost peripheral surface, and a colored ink was applied thereto by screen printing.

  A conductive polymer orgacon P3040 (trade name, manufactured by Agfa Co., Ltd.) as the transparent electrode layer 11 was screen-printed and applied to the film coated with the colored ink.

  A light emitting layer 12 was formed by a wet method at a place where light emission was necessary on the film on which the transparent electrode layer 11 was printed. As a binder, a polyester-based EG-000 medium (trade name, manufactured by Teikoku Ink Manufacturing Co., Ltd.) and EL phosphor GGS22 (trade name, manufactured by OSRAM Sylvania) were mixed at a weight ratio of 1: 1, and the light emitting layer ink and did.

  An insulator paste 8153N EL insulator paste (trade name, manufactured by DuPont) was applied as a dielectric layer 13 to the film on which the light emitting layer 12 was screen-printed.

  A conductive paste 7152 EL carbon paste (trade name, manufactured by DuPont) was applied as a counter electrode layer 14 to the film coated with the dielectric layer 13 by screen printing. Thus, an EL sheet 2 was formed.

  On the EL sheet 2 formed by applying the counter electrode layer 14, a polycarbonate ink Noriphan HTR (trade name, manufactured by Prowl) was printed as a film adhesive layer 15 at a position in contact with the resin forming the core material 3.

  The EL sheet 2 on which the film adhesive layer 15 was formed was set in a die having a key top shape and drawn at a mold temperature of 120 ° C. Next, polycarbonate resin was injected into the recesses by injection molding on the drawn EL sheet 2.

  Thus, an illuminated pushbutton switch member 1 that does not cause delamination between the transparent electrode 9 and the light emitting layer 12 even after molding was obtained.

  As the dielectric layer 13, an insulator paste 8153N EL insulator paste (trade name, manufactured by DuPont) and ion exchange resin IXE600 (antimony-bismuth system, product name, manufactured by Toagosei Co., Ltd.) for both ions are used. Dispersed by mass%, screen-printed and applied. The others were the same as in Example 1.

  As a result, a highly durable illuminated pushbutton switch member 1 was obtained.

It is principal part sectional drawing of the switch using the member for illumination type pushbutton switches which concerns on best embodiment. It is a cross section which shows an example of the conventional illumination type pushbutton switch.

Explanation of symbols

1 Illuminated pushbutton switch member 2 EL sheet 3 Core material 4 Key top part
5 Light emitting part 6 Circuit board
7 fixed contact 8 disc spring 9 pressing projection 10 transparent insulating film 11 transparent electrode layer 12 light emitting layer 13 dielectric layer 14 counter electrode layer 15 film adhesive layer

Claims (6)

  In the EL sheet comprising a counter electrode layer, a dielectric layer, a light emitting layer, a conductive polymer transparent electrode layer and a sheet base material, the binder for the light emitting layer is different from the binder for the dielectric layer, And the EL sheet | seat characterized by having high adhesiveness with the said conductive polymer.   The translucent adhesive layer having high adhesiveness with the conductive polymer is further interposed between the conductive polymer transparent electrode layer and the sheet base material. EL sheet.   The binder for the light emitting layer is one or more resin binders selected from the group consisting of polyester, acrylic, cyanoacrylate, and ethylene vinyl acetate, or a synthetic rubber binder typified by urethane. The EL sheet according to claim 1 or 2.   The EL sheet according to any one of claims 1 to 3, wherein the dielectric layer uses a fluorine-based resin binder as a binder.   At least one of the counter electrode layer, the dielectric layer, the light emitting layer, the conductive polymer transparent electrode layer, and the translucent adhesive having high adhesion to the conductive polymer is obtained by dispersing an ion exchanger. The EL sheet according to claim 1, wherein the EL sheet is formed.   The EL sheet according to any one of claims 1 to 5, wherein a convex portion protrudes from the back side where the counter electrode layer is close to the front side where the transparent electrode layer is close, and a core corresponding to at least the key top shape on the back side of the convex portion. A member for an illuminated pushbutton switch, characterized by being filled with a material.

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