KR100897577B1 - Flexible Electro Luminescence Sheet with Increasing Size - Google Patents

Abstract

Urethane base film; A back electrode stacked on the base film and electrically connected to an external lead; A dielectric layer stacked on the back electrode; A phosphor layer stacked on the dielectric layer; A transparent insulating layer laminated on the phosphor layer; A transparent electrode layer stacked on the transparent insulating layer and electrically connected to another external lead; And a large area electroluminescent sheet comprising a urethane protective layer laminated on the transparent electrode layer is disclosed.

EL, electroluminescent, moisture resistant, urethane, flexible, reliable

Description

Flexible large area electroluminescent sheet {Flexible Electro Luminescence Sheet with Increasing Size}

The present invention relates to an electroluminescent sheet, and more particularly, to an electroluminescent sheet having excellent moisture resistance, flexibility and reliability, and suitable for a continuous manufacturing process.

Conventional advertising displays use neon lights, fluorescent lights, CCFL (Cold Cathode Fluorescent Lamp), such as backlighting to see the advertising content at night, and recently, a self-luminescent electroluminescent sheet (EL) was developed. .

The electroluminescent sheet is composed of a polyester transparent film, which is a kind of polymer film having excellent flexibility, transmission characteristics and heat resistance, and indium oxide (ITO) coated on the back of the polyester transparent film and having conductive properties and excellent light transmission. The formed front electrode layer, the fluorescent layer formed on the back surface of the front electrode layer, the dielectric layer formed on the back surface of the fluorescent layer, the back electrode layer formed on the back surface of the dielectric layer, and a protective layer formed on the back electrode layer back surface.

In order to manufacture such an electroluminescent sheet, a discontinuous process such as screen printing or a continuous process such as a roll screen is usually used. In particular, continuous processes such as roll screens are widely applied in terms of reducing production costs and improving productivity.

However, according to the conventional continuous process, the front electrode layer is damaged in the process of passing through the roll and the heating chamber in the step of forming the fluorescent layer and the dielectric layer on the front electrode layer of the ITO, this damage is the ITO front electrode layer during the light emission of the electroluminescent sheet This can cause breakage due to overload. In particular, this problem occurs more seriously in large area electroluminescent sheets.

In addition, in the case of a large area electroluminescent sheet, the unevenness of the light emitting surface due to bending or wrinkles becomes a problem, and furthermore, there is a problem in that moisture resistance is weak.

Accordingly, it is an object of the present invention to provide a method for producing an electroluminescent sheet in which the ITO front electrode layer is produced in a post process so that the ITO front electrode layer is not damaged in a continuous manufacturing process.

Another object of the present invention is to provide a electroluminescent sheet manufactured by applying a continuous manufacturing process, having a large area and sufficient flexibility so that there is no problem of bending or wrinkles, and excellent moisture resistance.

The above object is a urethane base film; A back electrode stacked on the base film and electrically connected to an external lead; A dielectric layer stacked on the back electrode;

A phosphor layer stacked on the dielectric layer; A transparent insulating layer stacked on the phosphor layer; A transparent electrode layer stacked on the transparent insulating layer and electrically connected to another external lead; And a large area electroluminescent sheet having flexibility including a urethane protective layer laminated on the transparent electrode layer.

Preferably, the base film and the urethane protective layer may be formed by coating a liquid urethane on a release treatment surface, laminating a urethane sheet, or laminating thermoplastic urethane after the release treatment of the carrier film.

Preferably, the dielectric layer, the phosphor layer, the transparent insulating layer, and the transparent electrode layer are formed to have the same width smaller than that of the back electrode, and first bus bars are formed at both edges of the back electrode in the longitudinal direction, respectively, and an upper portion of the transparent electrode layer. Second bus bars may be formed at both edges in the longitudinal direction.

More preferably, power may be applied to any one of the first bus bars and the second bus bar diagonally opposite to any one of the first bus bars.

In addition, a copper foil having the same width may be provided on the transparent electrode layer in correspondence with the second bus bar.

The outer lead is electrically connected to the transparent electrode layer by crimping between the second bus bar and the copper foil from the longitudinal end, or by crimping between the first bus bar and the rear electrode from the longitudinal end. It may be electrically connected to the back electrode.

Preferably, through holes are formed in the base film and the protective layer, respectively, and the outer lead may be electrically connected to the back electrode or the transparent electrode layer through the through holes.

Further, preferably, through holes are formed in the base film and the protective layer, respectively, and the outer lead may be electrically connected to the back electrode or the copper foil, respectively, through the through holes.

According to the present invention, the front transparent electrode layer including ITO is not damaged in a continuous manufacturing process, thereby preventing disconnection due to overload during light emission of the electroluminescent sheet.

In addition, by applying a urethane material to the base film and the protective layer, there is an advantage that by having a thin film thickness has sufficient flexibility and excellent moisture resistance.

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

1 is a cross-sectional view showing an electroluminescent sheet according to the present invention, Figure 2 is a plan view.

Referring to FIG. 1, an electroluminescent sheet according to the present invention includes a back electrode 20, a dielectric layer 30, a phosphor layer 40, a transparent insulating layer 50, a transparent electrode layer 60, and a base film 10. The protective layer 70 has a structure in which sequentially stacked.

According to this structure, unlike the related art, by having the structure laminated in reverse, even if the laminate passes through the roll and the heating chamber to form the phosphor layer 40 or the dielectric layer 30, the transparent electrode layer 60 such as ITO is formed. Since it is not yet formed, no damage occurs.

According to the present invention, the base film 10 is made of a urethane material, and thus is made of a urethane material, so that the moisture resistance is strong and has a thin film thickness, so that the thickness of the electroluminescent sheet as a whole is not only flexible but also easy to process. There is an advantage.

Since the base film 10 itself has a thin film thickness of 50 to 125 μm, a carrier film, for example, a PET film, which has been released by silicon or the like, is formed thereon as a support, and then the carrier film is removed.

To this end, liquid urethane is coated on the release treatment surface of the carrier film, or the urethane sheet is laminated, or thermoplastic urethane is extruded and laminated using a T-die.

The back electrode 20 formed on the base film 10 has a width smaller than that of the base film 10 so that both sides thereof are exposed to the outside. The back electrode 20 may be formed by coating the entire surface using a conductive ink such as silver paste or carbon paste, or laminating aluminum foil or copper foil.

Bus bars 21 and 22 electrically connected to the external leads 81 and 82 are formed on both sides of the rear electrode 20 exposed to the outside in the longitudinal direction.

A dielectric layer 30 having a narrower width than that of the back electrode 20 is formed on the back electrode 20, and may be formed to a thickness of 10 to 50 μm.

The phosphor layer 40 is coated on the dielectric layer 30. Usually, the phosphor powder and the binder are used in combination at a predetermined ratio. The compounded phosphor paste may be mixed with 0.2 to 5% of pink pigment to emit white light, and may be preferably formed to an appropriate thickness, for example, 20 to 80 μm, to adjust brightness and color.

According to the present invention, the transparent insulating layer 50 serving as a binder is coated on the phosphor layer 40 so that the transparent electrode layer 50 can be smoothly deposited and the reliability of the light emitting sheet is improved. In particular, the phosphor layer 40 includes a large number of pores of a large size, the upper transparent electrode layer 50 and the lower back electrode 20 can be electrically connected to cause a short, the transparent insulating layer 50 Adding these eliminates this problem and improves reliability.

Bus bars 61 and 62 are formed at both edges of the transparent insulating layer 50 in the longitudinal direction to correspond to the bus bars 21 and 22 formed at both edges of the back electrode 20, respectively. By forming the bus bars 61, 62 and 21 and 22 in this manner, when the width of the sheet is narrow, the bus bars that are diagonal to each other, for example, the bus bars 21 and 62 and 22 and 61, are formed. It can be used as a pair of power supply terminals, and in the case of a wide power supply, the bus bars 21, 22, 61, and 62 can all be electrically stable.

According to such a configuration, there is an advantage that the light emission is uniform at the entire surface by applying power in the entire longitudinal direction in the diagonal direction to each other. In addition, when the intermediate portion of the electroluminescent sheet is cut, there is an advantage that the bus bars 21, 61 and 22, 62 can be used as a pair of power supply terminals.

The transparent electrode layer 60, for example, ITO, is deposited on the transparent insulating layer 50 on which the bus bars 61 and 62 are formed. At this time, as shown in FIG. 2, masking tapes 100 and 101 are masked on the exposed back electrode 20 including the bus bars 21 and 22, including portions of both edges of the transparent insulating layer 50. After that, ITO deposition is performed.

The electric resistance value of the transparent electrode layer 60 is appropriately 50 to 500 Ω, and the appropriate resistance value is determined according to the width of the electroluminescent sheet.

After the transparent electrode layer 60 is formed, the masking tapes 100 and 101 are removed, and then the urethane protective layer 70 is formed on the entire surface.

The urethane protective layer 70 may be coated with a liquid urethane on a front surface in a roll-coating manner, or may be laminated using a urethane sheet. In addition, thermoplastic urethane may be formed by extrusion after extrusion using a T-die.

In the case of coating the liquid urethane, the bus bars 21, 22, 61, and 62 are masked at regular intervals so that the portion not coated with urethane is used as a passage connected to the outer leads 81 and 82 later. . In addition, when laminating a urethane sheet or laminating | stacking thermoplastic urethane after extrusion, the copper bars 71 and 72 of the same width | variety as the bus bars 21, 22, 61, 62, etc. are first bus buses 21, 22, 61, 62) and overlap so that it may overlap (FIG. 1 shows only the case where it laminated on the bus bars 61 and 62). In this case, a passage connected to the outer leads 81 and 82 is formed later in the formed urethane protective layer 70.

When connecting the outer leads 81 and 92, the ends of the outer leads 81 and 82 are inserted in the space between the second bus bars 61 and 62 and the corresponding copper foils 71 and 72, and then compressed Connect. In other words, when the sheet is cut to a certain length in the longitudinal direction, a space is formed between the copper foils 71 and 72 and the second buses 61 and 62 bonded to the urethane protective layer 70 at the end thereof. The ends of the leads 81, 82 are fitted here and then pressed to make electrical connections. This method is equally applicable to the case where the external leads 81, 82 and the first buses 21, 22 are electrically connected.

3 is a perspective view illustrating connecting the outer lead 81 and the back electrode 20 through the passage 12 formed in the base film 10. In this case, the external lead 81 and the back electrode 20 may be connected through the passage 12 using solder, for example. 3 also applies to the case where the copper foils 71 and 72 and the outer lead 82 formed on the transparent electrode layer 60 are connected.

In the finished electroluminescent sheet, power is applied to the bus bars 21, 22, 61, and 62 by the external leads 81 and 82 to the back electrode 20 and the front transparent electrode layer 60.

According to the present invention having the above structure, the front electrode layer is not damaged in the continuous manufacturing process by having a reverse laminated structure in which a transparent electrode layer such as ITO is formed after the dielectric layer and the phosphor layer.

In addition, by using a urethane material for both the lower base film and the upper protective layer, it is possible to form a very thin thickness of the sheet as a whole has flexibility and excellent moisture resistance.

The present invention is not limited to the above embodiments, and various changes and modifications can be made by those skilled in the art. Accordingly, the scope of the present invention should not be limited to the above embodiments but should be interpreted by the claims that follow.

1 is a cross-sectional view showing an electroluminescent sheet according to the present invention.

2 is a plan view of FIG. 1.

3 is a perspective view illustrating connecting the outer lead and the rear electrode through a passage formed in the base film.

Claims (9)

Urethane base film; A back electrode stacked on the base film and electrically connected to an external lead; A dielectric layer stacked on the back electrode; A phosphor layer stacked on the dielectric layer; A transparent insulating layer laminated on the phosphor layer; A transparent electrode layer stacked on the transparent insulating layer and electrically connected to another external lead; And It includes a urethane protective layer laminated on the transparent electrode layer, The dielectric layer, the phosphor layer, the transparent insulation layer, and the transparent electrode layer are formed to have the same width smaller than that of the back electrode, and first bus bars are formed on both edges of the back electrode in the longitudinal direction, respectively, and on both upper edges of the transparent electrode layer. A large area electroluminescent sheet having flexibility, wherein a second bus bar is formed in the longitudinal direction. The method according to claim 1, The base film and the urethane protective layer may be formed by coating a liquid urethane on a release treatment surface, laminating a urethane sheet, or laminating thermoplastic urethane after the release treatment of the carrier film. Large area electroluminescent sheet. delete The method according to claim 1, A large-area electroluminescent sheet having flexibility, wherein power is applied to one of the first bus bars and the second bus bar diagonally opposite to any one of the first bus bars. The method according to claim 1, A large area electroluminescent sheet having flexibility, wherein copper foils having the same width are provided on the transparent electrode layer in correspondence with the second bus bars. The method according to claim 1, Through-holes are formed in the base film and the protective layer, respectively, and the outer lead is large area electroluminescent sheet having flexibility, characterized in that electrically connected to the back electrode or the transparent electrode layer through the through-holes. The method according to claim 5, Through holes are formed in the base film and the protective layer, respectively, and the outer lead is a large area electroluminescent sheet having flexibility, characterized in that electrically connected to the back electrode or the copper foil, respectively through the through holes. The method according to claim 5, Wherein said outer lead is sandwiched between said second bus bar and said copper foil from a longitudinal end and electrically connected to said transparent electrode layer by crimping. The method according to claim 5, The outer lead is a large area electroluminescent sheet having flexibility, characterized in that it is connected between the first bus bar and the back electrode from the longitudinal end and electrically connected to the back electrode by compression.

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