KR100817142B1 - Flexible EL Sheet Integral Keypad and Manufacturing Method Thereof - Google Patents

Abstract

The present invention relates to an EL sheet for mobile phones and a method of manufacturing the EL sheet is integrated with the keypad integrally improve the feeling of click, simple structure and manufacturing process, the EL sheet integral keypad of the present invention is a polyurethane (Polyurethane) film And an EL sheet having an indium thin oxide (ITO) layer, a fluorescent layer, a dielectric layer, a back electrode, and a protective layer on the composite film on which the base film is laminated; and an EL sheet laminated on the upper surface of the EL sheet by silicon molding. A key panel on which light exit parts of various shapes in which light can be emitted are printed; And a silicon sheet having a protrusion formed at a lower portion of the lower surface of the EL sheet, the protrusion for pressing the contacts of the printed circuit board.

According to the above configuration, the EL integrated keypad manufacturing method can print or injection molding liquid silicon to form a silicon protrusion on the back of the EL sheet, and does not require a separate silicon layer (steel use stainless) or plastic. Since it can be directly laminated with a plastic key panel, the manufacturing process can be simplified and the cost can be reduced.

Cell Phone, Keypad, Backlight, EL Sheet, Silicone Molding

Description

Flexible EL sheet integrated keypad and its manufacturing method {EL keypad and manufacturing method of the same using flexible EL seet}

1 is a cross-sectional view showing the structure of a keypad of a portable terminal using a metal dome sheet according to the prior art,

2 is a cross-sectional view showing the structure of a keypad of a portable terminal using a silicon sheet according to the prior art;

3 is a cross-sectional view showing the structure of an EL sheet according to the prior art;

4 is a cross-sectional view showing the structure of an EL sheet integrated keypad according to an embodiment of the present invention;

5 is a sectional view showing the structure of an EL sheet according to an embodiment of the present invention;

6 is a flowchart showing a process of manufacturing an EL sheet according to an embodiment of the present invention;

7 is a flowchart showing a process of manufacturing an EL sheet integrated keypad according to an embodiment of the present invention.

** Explanation of symbols for main parts of drawings **

10: transparent conductive film 20: EL layer

11: polyurethane film 12: basic film

13: transparent electrode layer (ITO layer) 14: auxiliary film

100: EL sheet 200: silicon sheet

300: key panel

The present invention relates to a keypad of a portable terminal, and more particularly, to an EL keypad for a mobile phone and a method of manufacturing the same, in which the EL sheet is integrally combined with the keypad, thereby improving a feeling of clicking, and having a simple structure and manufacturing process.

In general, the keypad is a switching device for signal generation used in an electronic device such as a mobile communication terminal or a remote control, and should have a separate backlight device for identifying keys such as numbers and letters at night or in a dark place.

Conventionally, as a keypad backlight device of a mobile communication terminal, a chip LED (Light Emitting Diode) is mounted on a printed circuit board of a mobile phone and a reflective film is installed on a metal dome sheet to diffuse light to the front so that the illumination of the keypad of a mobile phone or an electronic device is improved. It was configured to be made. However, since the LED is a point light source, it is reflected by a reflective film to illuminate by diffusing light only on the key top portion of the keypad. However, the LED has the advantage of identifying letters or numbers printed on the surface of the key button portion of the keypad. There is a problem of low visibility and high power consumption.

In order to solve this problem, in recent years, a keypad backlight device using an EL sheet (Electroluminescent sheet) has been developed in place of the LED as a light source of the backlight of the mobile communication terminal. In connection with the backlight for a keypad using such an EL sheet, the applicant has also filed 10-2005-0000778 and 10-2005-0119024, and keypads having various structures using the EL sheet have been developed and released.

1 and 2 show a structure of a keypad of a portable terminal according to the prior art, Figure 1 is a structure of a keypad using a metal dome sheet, Figure 2 shows a structure of a keypad using a rubber sheet, Figure 3 shows the structure of the EL sheet used for such a keypad.

As shown in FIG. 1, the metal dome keypad using the EL sheet according to the related art forms a structure in which the key panel 1, the EL sheet 2, and the metal dome sheet 3 are laminated, but is not shown. A flexible printed circuit board is positioned below the metal dome sheet 3.

Here, the key panel 1 is for the user to directly press the keypad, and the front surface is printed so that light is transmitted from the bottom of the numbers, letters, figures, etc., and the EL sheet 2 is a backlight light source from the keypad at the bottom of the key panel. In the metal dome sheet 3, holes for inserting the metal dome 3 'are formed in the lower portion of the EL sheet.

The conventional keypad having such a structure has a separate top tape or adhesive or the like composed of double-sided tape for laminating the key panel 1 and the EL sheet 2, the EL sheet 2 and the metal dome sheet 3, respectively (5). Is used, and a separate metal dome sheet and a metal dome 3 'for inserting therein are required in order to compress the contacts of the flexible printed circuit board (FPCB) located at the bottom, and the metal The dome sheet 3 and the metal dome 3 'are also laminated to the EL sheet by the top tape or the adhesive 5.

This not only complicates the overall configuration of the keypad, but also requires a step of laminating with a tape or adhesive in the manufacturing process, and a demanding process for inserting the metal dome into the hole of the metal dome sheet. In addition, when the inserted metal dome is used for a long time, the adhesive force may be separated, thereby causing malfunctions of the mobile phone.

In order to solve this problem, as shown in FIG. 2, a keypad in which the rubber sheet 4 is integrally developed on the back of the EL sheet has been developed, but in the case of the keypad using the rubber sheet 4, the key panel 1 and To laminate the EL sheet 2, the EL sheet 2 and the rubber sheet 4, respectively, a top tape or an adhesive 5 is used, and although not shown, a separate silicon forming process is provided on the back of the EL sheet for adhesion. Required.

On the other hand, the general structure of the EL sheet used for the backlight for the keypad has an indium thin oxide (ITO) layer 12 formed on the base film 11 to form a transparent conductive film, as shown in Figure 3, a transparent conductive film The fluorescent layer 21, the dielectric layer 22, the back electrode 23, and the protective layer 24 are sequentially stacked on the substrate.

However, when the ITO layer, the fluorescent layer, the dielectric layer, etc. are formed on the base film 11, since the film is made in a high temperature environment, the base film 11 having a single structure is easily deformed by the high temperature heat, thereby preventing this. In order to base film 11 should be more than a predetermined thickness. In this case, the thicker the base film is, the thicker the overall thickness of the EL sheet becomes, and a problem arises in that a feeling of clicking decreases when the keypad is operated.

The present invention has been proposed to solve the above problems, EL sheet and the EL sheet which can improve the feeling of click while preventing the thermal deformation occurring during the manufacturing process by forming a base film of the EL sheet in a thin multilayer structure It is an object to provide a manufacturing method.

Another object of the present invention is to use the EL sheet as described above so that the EL sheet is directly laminated to the key panel without the need for a separate silicon forming process on the back of the EL sheet, so that the overall structure of the keypad is thin and the structure is simple and manufactured. It is to provide an EL sheet-integrated keypad and a method of manufacturing the same, which can simplify the process.

EL sheet integrated keypad of the present invention for achieving the above object is an indium thin oxide (ITO) layer, a fluorescent layer, a dielectric layer, a back electrode and a protective layer on a composite film laminated a polyurethane film and a base film A key panel having a light emitting part having various shapes, which are laminated on the upper surface of the EL sheet by silicon molding and can emit light of the EL sheet; A first silicon sheet for laminating the key panel and the EL sheet between the key panel and the EL sheet; And a silicon sheet having a protrusion formed at a lower portion of the lower surface of the EL sheet, the protrusion for pressing the contacts of the printed circuit board.

In the above-described configuration, the polyurethane film is composed of a thickness of 5㎛ to 20㎛, the base film is characterized in that composed of a thickness of 5㎛ 25㎛.

In the above-described configuration, the first silicon sheet and the EL sheet is characterized in that it is configured to be inserted while bent into the light transmitting portion of the key panel.

In addition, the EL sheet integrated keypad manufacturing method of the EL sheet integrated keypad in which the EL sheet is laminated on the key panel, the transparent electrode layer, the fluorescent layer, the dielectric layer, the back on the composite film laminated with the polyurethane film and the base film An EL sheet manufacturing step of forming an electrode and a protective layer; and a first silicon forming step of forming protrusions on a bottom surface of the EL sheet; And a second silicon molding step of laminating the polyurethane film of the key panel and the EL sheet. Alternatively, the first silicon molding step and the second silicon molding step may be performed simultaneously.

In the above-described configuration, the EL sheet manufacturing step comprises the steps of laminating a polyurethane film on the auxiliary film, laminating the base film on the polyurethane film and forming a transparent electrode layer to produce a transparent conductive film having a multilayer structure; and Forming a fluorescent layer, a dielectric layer, a back electrode layer and a protective layer on the transparent conductive film to produce an EL layer; and removing the auxiliary film on the back of the polyurethane film; characterized in that it comprises a .

In the above-described configuration, the transparent electrode layer of the transparent conductive film is formed by depositing ITO, or is formed by screen printing the ITO or conductive polymer.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 4 shows the structure of the EL sheet integrated keypad according to an embodiment of the present invention, Figure 5 is a cross-sectional view showing the structure of the EL sheet according to an embodiment of the present invention.

Referring to FIG. 4, in the keypad according to the embodiment of the present invention, the key panel 300 is laminated on the upper surface of the EL sheet 100, and the silicon sheet 200 having protrusions is formed on the rear surface of the EL sheet 100. Is formed.

In more detail, the above-described key panel 300 is a panel made of a steel use stainless steel or plastic material, and a light-transmitting part 310 through which light is transmitted from the lower EL sheet 100 is formed. The light emitting unit 310 is formed in various shapes such as numbers, letters, shapes, etc. required for the keypad of the mobile phone, through which light or light emitted outside can recognize numbers or letters even at night or in a dark place. Will be.

As described above, the EL sheet 100 has a structure in which the EL layer 20 is formed on the transparent conductive film 10 on which the polyurethane film 11 and the base film 12 are laminated.

The transparent conductive film 10 is a double-layered transparent conductive film in which a polyurethane film 11 and a base film 12 are laminated, and an ITO layer 13 is formed as a transparent electrode layer on the laminated base film 12. It is composed. The base film 12 may be composed of polyethylene terephthalate (PET) film or polycarbonate (PC) film, polyethylene naphthalate (PEN, polyethylene naphtalate) film, or the like.

In general, the EL sheet uses a transparent conductive film having an ITO layer formed on a single base film. However, in the embodiment of the present invention, a double structure film (11, 12) in which a polyurethane (PU) film and a base film are laminated is laminated. ) To form a structure in which an ITO layer 13, which is a transparent electrode layer, is formed.

The single base film according to the prior art has a problem that the thickness of the EL sheet is at least 50 μm or more, and the whole EL sheet is thick, and the click feeling of the keypad is inferior, but the multilayer structure according to the embodiment of the present invention is transparent. The conductive film 10 is laminated with a PU film 13 of 5 μm to 20 μm and a base film 11 such as PET film of 5 μm to 25 μm to reduce the overall thickness, and at the same time exhibit the flexible characteristics of the polyurethane film. It can have a significantly improved clicking feeling of the keypad.

That is, according to an embodiment of the present invention, a transparent conductive film having a structure in which two films (PU and PET or PC and PEN) are completely laminated has the ductility of the PU film and the characteristics of the PET film at the same time. The disadvantages of the film can be compensated for.

On the other hand, an EL layer on which a bus bar and a phosphor layer, a dielectric layer, a back electrode, a protective layer, and the like are stacked is formed on the transparent conductive film, and a detailed configuration of such a bus bar and the EL layer will be omitted. .

Referring to FIG. 4 again, the aforementioned silicon sheet 200 has a protrusion 210 formed on a lower surface of the silicon sheet 200 so as to be in contact with a contact point of a printed circuit board (FPCB, not shown) positioned below the keypad. Liquid silicone is formed directly on the back of the sheet 100 by printing or injection molding.

The key panel and the EL sheet are also directly laminated by the injection molded silicon 320. The transparent conductive film front surface of the EL sheet is composed of a double of a PU film and a PET film, and is laminated on the front surface of the EL sheet 100 by silicon 320 injection-molded without a separate silicon process.

In particular, according to an embodiment of the present invention, when the key panel and the EL sheet are laminated by silicon injection, as shown in (b), the EL sheet 100 may be formed of the silicon 320 due to the ductility of the PU film 11. It is laminated together while being inserted into the light transmitting portion 310 of the key panel 300. In this case, by the EL sheet structure inserted into the light transmitting portion of the key panel, visibility from the outside during keypad operation can be further improved.

FIG. 6 is a flowchart illustrating a process of manufacturing an EL sheet of a multilayer structure according to an embodiment of the present invention, and FIG. 7 is a flowchart illustrating a process of manufacturing a keypad using the EL sheet of FIG.

In the method of manufacturing an EL sheet according to an embodiment of the present invention, as shown in (A), a step of preparing a transparent conductive film (S10) and a step of forming an EL layer on the transparent conductive film (S20), as described above It comprises a step (S30) of removing the auxiliary film from the EL sheet produced by the process.

Looking in more detail, the step (S10) of manufacturing the above-mentioned transparent conductive film is to prepare a secondary film to laminate a polyurethane (PU, Polyurethane) film on the auxiliary film (S11, S12), and to laminate the base film thereon ( S13), an ITO layer is formed on the base film as a transparent electrode layer (S14).

Here, the basic film is a polyethylene terephthalate (PET) film or a polycarbonate (PC, Polycarbonate) film, polyethylene naphthalate (PEN, Polyethylene Naphtalate) film of 5㎛ to 25㎛ thickness is used, the polyurethane film 5 μm to 20 μm thick films are used.

In addition, the transparent electrode layer may be formed by depositing ITO or screen printing an ITO paste or a conductive polymer. Especially when EL sheet forming is required, if ITO paste or conductive polymer is screen printed to form a transparent electrode layer, the paste-type transparent electrode layer also has a ductility, thereby preventing breakage during lamination and improving product reliability. have.

A fluorescent layer, a dielectric layer, a back electrode, and a protective layer are formed on the transparent conductive film prepared as described above (S21 to S25) to form an EL layer (S20). The auxiliary film laminated on the back surface of the transparent conductive film on which the EL layer is formed is removed again (S30).

In the EL sheet manufacturing method according to an embodiment of the present invention, a transparent conductive film is prepared using a polyurethane film and a base film such as PET, which is two kinds of thin films having different properties. In this case, two thin films having different properties may generate curl due to thermal deformation due to differences in film properties in repeated high temperature heat treatment processes.

Therefore, in the embodiment of the present invention, the auxiliary film 14 is used to prevent curling as shown in FIGS. 5 and 6, and the auxiliary film 14 is finally removed.

As shown in FIG. 7, a silicon sheet is formed on the rear surface of the EL sheet manufactured by the process S100 as described above so that the contact protrusion is provided (S200). This silicon sheet is formed by printing or injection molding liquid silicon on the back of the EL sheet.

The key panel is laminated on the back of the EL sheet on which the silicon sheet is formed (S300). In the present invention, the EL sheet is placed on the top of the key panel, and the silicon is injected and laminated.

According to the prior art, a key panel in which a silicon pad is separately laminated on the back of the key panel is manufactured, and the silicon pad is laminated with the EL sheet. However, according to the present invention, as described above, the front surface of the EL sheet is made of a polyurethane film, so that a key panel made of metal or plastic can be directly laminated using silicon molding without the need for a separate silicon pad on the back of the key panel. It is.

Meanwhile, in FIG. 7, a step of forming a silicon sheet on the back surface of the EL sheet (S200) and laminating the key panel on the front surface (S300) is performed separately, but by placing the EL sheet on the key panel and injection molding silicon, A silicon sheet may be formed on the back of the sheet, and the process of laminating the EL sheet and the key panel may be performed at the same time.

That is, liquid silicon is injected while the EL sheet is placed on the key panel, and pressurized for about 1 minute at a temperature of about 150 ° C. to form a silicon sheet having protrusions, and the EL sheet can be laminated to the key panel at the same time. have.

Although the present invention has been described in detail through specific embodiments, the present invention is not limited to the above-described embodiments, and various changes may be made by those skilled in the art to which the present invention pertains without departing from the spirit and scope of the present invention. It may be changed and implemented.

As described above, the EL integrated keypad according to the present invention is excellent in the click feeling of the keypad by the transparent conductive film of the multiple structure in which the polyurethane film is laminated, and the thickness of the keypad becomes thinner.

In addition, the EL integrated keypad manufacturing method according to the present invention can form a silicon protrusion on the back of the EL sheet by printing or injection molding liquid silicon, and does not require a separate silicon layer (steel use stainless) or plastic ( Since it can be directly laminated with the plastic key panel, the manufacturing process can be simplified and the cost can be reduced.

Claims (8)

In the EL seat integrated keypad, An EL sheet having an ITO layer, a fluorescent layer, a dielectric layer, a back electrode, and a protective layer formed on a base film of a composite film in which a polyurethane film and a base film are laminated; Wow A key panel laminated on an upper surface of the polyurethane film of the EL sheet and having light transmitting parts having various shapes through which light of the EL sheet can be transmitted; A first silicon sheet for laminating the key panel and the EL sheet between the key panel and the polyurethane film of the EL sheet; And And a second silicon sheet having a protrusion formed at a lower portion of the protective layer on the lower surface of the EL sheet, the protrusion for pressing the contact of the printed circuit board. The EL sheet integrated keypad of claim 1, wherein the polyurethane film has a thickness of 5 μm to 20 μm, and the base film has a thickness of 5 μm to 25 μm. The EL sheet integrated keypad according to claim 1 or 2, wherein the first silicon sheet and the EL sheet are configured to be inserted while being bent into the light transmitting portion of the key panel. In the EL sheet integrated keypad manufacturing method in which the EL sheet is laminated on the key panel, An EL sheet manufacturing step of forming a transparent electrode layer, a fluorescent layer, a dielectric layer, a back electrode, and a protective layer on the base film of the composite film in which the polyurethane film and the base film are laminated; Wow, A first silicon forming step of forming a projection for contacting the printed circuit board on a rear surface of the protective layer of the EL sheet; And A second silicon forming step of laminating the polyurethane film of the key panel and the EL sheet; EL sheet integrated keypad manufacturing method comprising a. 5. The EL sheet integrated keypad manufacturing method according to claim 4, wherein the first silicon forming step and the second silicon forming step are performed by placing the manufactured EL sheet on the key panel and injecting silicon into the same. Way. The method of claim 4 or 5, wherein the EL sheet manufacturing step is Manufacturing a transparent conductive film having a multilayer structure by laminating a polyurethane film on an auxiliary film, laminating a base film on the polyurethane film, and forming a transparent electrode layer; Wow Manufacturing an EL layer by forming a fluorescent layer, a dielectric layer, a back electrode layer, and a protective layer on the transparent conductive film; And Removing the auxiliary film on the back of the polyurethane film; EL sheet integrated keypad manufacturing method characterized in that it comprises a. 7. The method of claim 6, wherein the transparent electrode layer of the transparent conductive film is formed by depositing indium thin oxide (ITO). 7. The method of claim 6, wherein the transparent electrode layer of the transparent conductive film is formed by screen printing an indium thin oxide (ITO) paste or a conductive polymer.

Images