KR100415326B1 - AC powder EL device and fabrication method thereof - Google Patents

Abstract

AC powder EL device according to the present invention, the lower polymer protective film; A noise shielding film formed by mixing copper, graphite, or silver powder encapsulated with a conductive material and a conductive binder; A polymer shielding film made of a nonpolar polymer; A lower electrode layer formed by mixing a copper, graphite, or silver powder encapsulated with a conductive material and a conductive binder; A first electric field polymer layer made of a polar polymer; A dielectric film formed by mixing a dielectric powder and a binder for the dielectric material; A second electric field polymer layer made of a polar polymer; A light emitting layer formed by mixing a light emitting powder and a light emitting binder; An enhancement layer formed by mixing the dielectric powder and the binder for the dielectric; And a structure in which the upper transparent electrode layers are sequentially stacked. According to the present invention, while the luminance is high, the current flows less, the power consumption is lower than in the prior art, and the influence of noise can be reduced, so that the EL element has a long life and good electrical characteristics.

Description

AC powder EL device and fabrication method

The present invention relates to an AC powder EL (ElectroLuminescence) device and a method for manufacturing the same, in particular, a high-life AC powder having a low luminance, a low current consumption, low power consumption, and a long life that can reduce the influence of noise. An EL device and a method of manufacturing the same.

Today, liquid crystal displays are used in notebook computers, cell phones, watches and more. A light source is required to display information through liquid crystals. Small devices such as watches and electronic calculators use reflective liquid crystal devices that use natural light, and display devices of notebook computers and mobile phones are light sources behind liquid crystals. For example, it is common to use a transmissive liquid crystal device using a backlight or a light emitting diode element. However, since the light emitting elements used in the latter case are heavy and have high power consumption, attention has recently been focused on thin and light EL elements.

The conventional powder powder EL element for alternating current has a low brightness and its use is very limited. In particular to apply a backlight for an LCD in demand is expected, and the brightness should be at least 100 to 150cd / m ² or so, when you consider the loss of light when you want to apply to the STN (Super Twisted Nematic) Class 120cd / m ² degree Should be. By the way, the brightness | luminance of AC powder EL element is only a problem about 70-80 cd / m <^2> at present. In addition, there is a disadvantage in that a large amount of current flows in the device when high luminance is obtained.

In addition, since the conventional AC powder EL device consumes a lot of power, when used as a light source of a portable information communication device, the battery usage time is short, and the life of the EL device itself is short. In addition, there is a problem that the EL element is affected by noise a lot and an error occurs in the operation.

Accordingly, the technical problem to be achieved by the present invention is to provide an AC powder EL device having a high brightness and a long lifespan capable of reducing electric current, reducing power consumption, and reducing the influence of noise. .

Another technical problem to be solved by the present invention is to provide an AC powder EL device manufacturing method suitable for achieving the above technical problem.

1 is a schematic view for explaining an AC powder EL device and a method of manufacturing the same according to the present invention;

FIG. 2 is an equivalent circuit of the EL element of FIG.

<Description of Reference Numbers for Main Parts of Drawings>

10: lower polymer protective film 20: noise shielding film

30: polymer shielding film 40: lower electrode layer

50: first electric field polymer layer 60: dielectric film

70: second electric field polymer layer 80: light emitting layer

90: enhancement layer 100: upper transparent electrode layer

110: upper polymer protective film

AC powder EL device according to the present invention for achieving the above technical problem: a lower polymer protective film; A noise shielding film formed on the lower polymer protective film and formed by mixing copper, graphite, or silver powder encapsulated with a conductive material, and a conductive binder; A first capacitor comprising: a polymer shielding film formed on the noise shielding film and made of a nonpolar polymer; A lower electrode layer formed on the polymer shielding film and formed by mixing copper, graphite, or silver powder encapsulated with a conductive material, and a conductive binder; A first electric field polymer layer formed on the lower electrode layer and made of a polar polymer, a dielectric film formed on the first electric field polymer layer and formed by mixing a dielectric powder and a binder for a dielectric material, and a second electric film formed on the dielectric film and made of a polar polymer A second capacitor formed on a second electric field polymer layer and the second electric field polymer layer, the light emitting layer being formed by mixing a light emitting powder and a light emitting binder, the second capacitor being equivalent to the first capacitor; An enhancement layer formed on the light emitting layer and formed by mixing a dielectric powder and a binder for the dielectric; And an upper transparent electrode layer formed on the enhancement layer, wherein a potential having the same polarity is applied to the noise shielding layer and the upper transparent electrode layer, and a polarity applied to the noise shielding layer and the upper transparent electrode layer to the lower electrode layer. AC power is applied to emit light so that a potential of different polarity is applied.

Here, the encapsulated copper powder of the noise shielding layer and the lower electrode layer may be encapsulated by coating the surface thereof with silver, and the polar polymer, the binder for the dielectric, or the binder for the light emitter may be cyanoethyl pullulan or fluororesin. It may be made, including.

The second electric field polymer layer or the enhancement layer may further include a fluorescent dye, and the fluorescent dye may use a red light emitting rhodamine dye type.

BaTiO ₃ powder having a size of 0.8 μm or less may be used as the dielectric powder of the dielectric layer or the enhancement layer. As the light emitting powder, a II-VI compound such as ZnS powder may be used. Preferably, the light emitter powder has a size of about 20 μm.

The binder for the light emitter preferably has a larger dielectric constant than the light emitter powder.

The upper transparent electrode layer may be formed by mixing a transparent conductive powder such as ITO powder and a transparent conductive binder including cyanoethyl pullulan or fluororesin.

According to another aspect of the present invention, there is provided a method for manufacturing an AC powder EL device according to the present invention by applying a copper, graphite, or silver powder and a conductive binder, the surface of which is coated with a conductive material on a lower polymer protective film, thereby applying a noise shielding film. Forming a; Applying a nonpolar polymer on the noise shielding film to form a polymer shielding film; Forming a lower electrode layer by mixing and coating a copper, graphite, or silver powder encapsulated with a conductive material on the polymer shielding film and a conductive binder; Applying a polar polymer on the lower electrode layer to form a first electric field polymer layer; Mixing and applying a dielectric powder and a binder for the dielectric on the first electric field polymer layer, and heat treating at a temperature ranging from 80 to 170 ° C. to form a dielectric film; Applying a polar polymer on the dielectric layer and instantaneous heat pressing at a temperature of 100 to 150 ° C. to form a second electric polymer layer; Mixing and applying a light-emitting powder and a light-emitting binder on the second electric field polymer layer and heat-treating at a temperature in a range of 100 to 150 ° C. to form a light emitting layer; Mixing and applying a dielectric powder and a binder for the dielectric on the light emitting layer and heat-treating at a temperature ranging from 80 to 170 ° C. to form an enhancement layer; And forming an upper transparent electrode layer on the enhancement layer.

Here, the upper transparent electrode layer may be formed by mixing and applying a transparent conductive powder and a liquid transparent conductive binder and heat treatment at a temperature in the range of 80 to 150 ℃. The noise shielding film, the polymer shielding film, the lower electrode layer, the first electric field polymer layer, the dielectric film, the second electric field polymer layer, the light emitting layer, the enhancement layer, and the upper transparent electrode layer may be formed by applying a spin coating or screen printing method.

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

1 is a schematic view for explaining an AC powder EL device and a method of manufacturing the same according to the present invention.

The noise shielding film 20 is coated with a conductive material on the surface 24 of the encapsulated copper, graphite, or silver powder 22, and the conductive binder is mixed and applied onto the lower polymer protective film 10. To form.

On the noise shielding film 20, a polymer shielding film 30 made of a non-polarity polymer is formed. Thermoplastic or UV polymer may be used as the material of the polymer shielding film 30.

The lower electrode layer 40 has a surface 44 coated with a conductive material on the polymer shielding film 30 in the same manner as in the case of the noise shielding film 20. The encapsulated copper, graphite, or silver powder 42 and the conductive binder are mixed with each other. It is then applied and formed. The conductive material used for the coating 44 preferably has a better conductivity than the target powder 42 to be coated. For example, when the copper powder surface is coated with silver and encapsulated.

On the lower electrode layer 40, a first electric field polymer layer 50 made of a polar polymer such as cyanoethyl pullulan or fluororezin is formed. The dielectric film 60 is formed by mixing a dielectric powder and a binder for the dielectric and applying the same on the first electric field polymer layer 50 and heat treatment at a temperature ranging from 80 to 170 ° C. so that the dielectric powder is rearranged densely to have a high dielectric constant. do. BaTiO ₃ powder having a size of 0.8 μm or less may be used as the dielectric powder, and a binder having a high dielectric constant such as cyanoethyl pullulan or fluororesin may be used as a binder for the dielectric for binding the dielectric powder. have.

The second electric field polymer layer 70 is formed by applying a polar polymer such as cyanoethyl pullulan or fluororezin on the dielectric layer 60 and instantaneous heat compression at a temperature of 100 to 150 ° C. do. As a result of the instantaneous heat compression process, the interlayer adhesion between the dielectric layer 60 and the second electric field polymer layer 70 is improved, and the dielectric constant of the dielectric layer 60 is increased.

Since the second electric field polymer layer 70 and the first electric field polymer layer 50 serve to reduce current leakage and increase an electric field, the second electric field polymer layer 70 and the first electric field polymer layer 50 increase the leakage current and the luminous efficiency of the EL element. Higher luminous efficiency results in longer lifetime when operating at the same brightness as conventional EL devices.

The light emitting layer 80 is mixed with a light emitting powder 82 having a size of about 20㎛ and a binder for the light emitting 86 and apply it on the second field polymer layer 70 and heat-treated at a temperature in the range of 100 to 150 ℃ Form. The higher the density of the light emitting layer 80 than in the conventional case. The emitter powder 82 may be made of a II-VI compound.

The binder 86 for the luminous material should serve to fix the luminous material powder 82 and at the same time fill the void space between the luminous material powder 82 to independently act as a dielectric. Therefore, it is preferable that the binder 86 for the emitter is made of a dielectric material in order to make the EL element having high luminance emission characteristics, and the binder 86 for the emitter is more than the emitter powder 82 to further enhance the intensity of the internal electric field. It is more desirable to have a large dielectric constant. For example, ZnS powder may be used as the emitter powder 82, and cyanoethyl pullulan or fluororesin may be used as the binder for the emitter 86.

The added layer 90 is formed by mixing the dielectric powder and the binder for the dielectric, applying the same on the light emitting layer 80 and heat treatment at a temperature in the range of 80 to 170 ° C. The enhancement layer 90 may be made of the same material as the dielectric layer 60. This heat treatment during formation of the augmentation layer 90 densely rearranges the dielectric powder, thereby increasing the dielectric constant of the augmentation layer 90 and ultimately increasing the luminance of the EL element.

The light emitted from the light emitting layer 80 is scattered in the enhancement layer 90 to use a dielectric powder in the enhancement layer 90 to enhance the uniformity of the light, thereby increasing the internal electric field to increase the light emission luminance.

In order to increase the luminous efficiency, the second electric field polymer layer 70 and the enhancement layer 90 formed on both surfaces of the light emitting layer 80 further include a fluorescence dye such as a red emission Rodamin dye type. May be included.

The upper transparent electrode layer 100 is formed by mixing the transparent conductive powder 102 and the liquid transparent conductive binder 106 and applying it on the enhancement layer 90 and heat-treating at a temperature in the range of 80 to 150 ℃. ITO powder may be used as the transparent conductive powder 102. In addition, cyanoethyl pullulan or fluororesin may be used as the transparent conductive binder 106, and InGa may be further included therein for better conductivity. The upper polymer protective layer 110 may be disposed on the upper transparent electrode layer 100. ).

Noise shielding film 20, polymer shielding film 30, lower electrode layer 40, first electric field polymer layer 50, dielectric film 60, second electric field polymer layer 70, light emitting layer 80, enhancement layer 90 ), And the upper transparent electrode layer 100 is formed by applying a spin coating or screen printing method. The upper transparent electrode layer 100 may be an ITO thin film formed by a sputtering method using a multi-target or a compound target without using ITO powder.

The spin coating method is a method of applying a thin and uniform film while rotating by dropping a liquid coating material onto a rotating plate. The screen printing method is a soft plastic bar placed on a silk or stainless steel mesh with a liquid coating material. It is a method of applying a thin and uniform film by rubbing with a (soft plastic bar) to allow the coating material to escape through the mesh.

FIG. 2 is an equivalent circuit of the EL element of FIG. Here, C1 is a capacitor formed by sequentially stacking the first electric field polymer layer 50, the dielectric film 60, the second electric field polymer layer 70, and the light emitting layer 80, and C2 is the polymer shielding film 30. Capacitor. When driving the EL element, AC power is applied to the noise shielding film 20, the lower electrode layer 40, and the upper transparent electrode layer 100.

In practice, the EL element forms an equivalent circuit with a capacitor in which a dielectric material is located between the plate electrodes. Therefore, when AC power is applied to the plate electrode, the electric field changes direction according to the operating frequency and acts on the internal dielectric, and the device vibrates according to the frequency by the electric field. In other words, the noise generated in the EL may be mainly caused by the vibration of the device due to the electrostriction. Therefore, reducing the vibration of such a device also reduces the noise.

In order to reduce vibration of the device, the present invention has a structure in which the noise shielding film 20, the polymer shielding film 30, and the lower electrode layer 40 are sequentially stacked. As shown in Fig. 2, when an operating AC power source is connected to an EL element, an electric field having a different direction and substantially the same size as the conventional EL element is applied to the EL element. Therefore, the electrical compressive force is alleviated, so that noise of the EL element due to vibration is reduced.

According to the powdered AC device for alternating current according to the present invention as described above and a method of manufacturing the same, the luminance is high, but the current flows less, the power consumption is lower, and the influence of noise can be reduced. This long electrical property is good.

The present invention is not limited to the above embodiments, and it is apparent that many modifications are possible by those skilled in the art within the technical spirit of the present invention.

Claims (18)

A lower polymer protective film; A noise shielding film formed on the lower polymer protective film and formed by mixing copper, graphite, or silver powder encapsulated with a conductive material, and a conductive binder; A first capacitor comprising: a polymer shielding film formed on the noise shielding film and made of a nonpolar polymer; A lower electrode layer formed on the polymer shielding film and formed by mixing copper, graphite, or silver powder encapsulated with a conductive material, and a conductive binder; A first electric field polymer layer formed on the lower electrode layer and made of a polar polymer, a dielectric film formed on the first electric field polymer layer and formed by mixing a dielectric powder and a binder for a dielectric material, and a second electric film formed on the dielectric film and made of a polar polymer A second capacitor formed on a second electric field polymer layer and the second electric field polymer layer, the light emitting layer being formed by mixing a light emitting powder and a light emitting binder, the second capacitor being equivalent to the first capacitor; An enhancement layer formed on the light emitting layer and formed by mixing a dielectric powder and a binder for the dielectric; And An upper transparent electrode layer formed on the enhancement layer; AC power is applied to emit light such that a potential of the same polarity is applied to the noise shielding film and the upper transparent electrode layer, and a potential of a polarity different from that applied to the noise shielding film and the upper transparent electrode layer is applied to the lower electrode layer. AC powder EL device characterized by the above-mentioned. 2. The powder EL device for alternating current as claimed in claim 1, wherein the encapsulated copper powder of the noise shielding film and the lower electrode layer is encapsulated with a surface coated with silver. 2. The powder EL device for alternating current as claimed in claim 1, wherein said polar polymer, said dielectric binder, or said light emitting binder comprises cyanoethyl pullulan or fluororesin. The powder EL device for alternating current as claimed in claim 1, wherein the second electric field polymer layer or the enhancement layer further comprises a fluorescent dye. The powder EL device for alternating current as claimed in claim 4, wherein the fluorescent dye is red light emitting rhodamine dye type. The powder EL device for alternating current as claimed in claim 1, wherein the dielectric powder of the dielectric film or the enhancement layer is BaTiO ₃ powder. 7. The powder EL device for alternating current as claimed in claim 6, wherein the dielectric powder has a size of 0.8 mu m or less. The powder EL device for alternating current as claimed in claim 1, wherein said light emitting powder is a II-VI compound. The alternating current powder EL device according to claim 8, wherein said light emitting powder is a ZnS powder. The powder EL device for alternating current as claimed in claim 1, wherein the light-emitting body powder has a size of about 20 mu m. The powder EL device for alternating current as claimed in claim 1, wherein the binder for the luminous material has a larger dielectric constant than the luminous material powder. The powder EL device for alternating current as claimed in claim 1, wherein the upper transparent electrode layer is formed by mixing a transparent conductive powder and a transparent conductive binder. The alternating current powder EL device according to claim 12, wherein said transparent conductive powder is ITO powder. The powder EL device for alternating current as claimed in claim 12, wherein the transparent conductive binder comprises cyanoethyl pullulan or fluororesin. delete Forming a noise shielding film by coating copper, graphite, or silver powder encapsulated with a conductive material on the lower polymer protective film to form a noise shielding film; Applying a nonpolar polymer on the noise shielding film to form a polymer shielding film; Forming a lower electrode layer by mixing and coating a copper, graphite, or silver powder encapsulated with a conductive material on the polymer shielding film and a conductive binder; Applying a polar polymer on the lower electrode layer to form a first electric field polymer layer; Mixing and applying a dielectric powder and a binder for the dielectric on the first electric field polymer layer, and heat treating at a temperature ranging from 80 to 170 ° C. to form a dielectric film; Applying a polar polymer on the dielectric layer and instantaneous heat pressing at a temperature of 100 to 150 ° C. to form a second electric polymer layer; Mixing and applying a light-emitting powder and a light-emitting binder on the second electric field polymer layer and heat-treating at a temperature in a range of 100 to 150 ° C. to form a light emitting layer; Mixing and applying a dielectric powder and a binder for the dielectric on the light emitting layer and heat-treating at a temperature ranging from 80 to 170 ° C. to form an enhancement layer; And And forming an upper transparent electrode layer on the enhancement layer. 17. The method of claim 16, wherein the upper transparent electrode layer is formed by mixing and applying a transparent conductive powder and a transparent transparent conductive binder and heat treatment at a temperature in the range of 80 to 150 ° C. The method of claim 16, wherein the noise shielding film, the polymer shielding film, the lower electrode layer, the first electric field polymer layer, the dielectric film, the second electric field polymer layer, the light emitting layer, the enhancement layer, and the upper transparent electrode layer are applied by spin coating or screen printing. AC powder EL device manufacturing method characterized in that it is formed.