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KR-102961822-B1 - ELECTROLUMINESCENT(EL) SHEET AND METHOD FOR MANUFACTURING THE SAME

KR102961822B1KR 102961822 B1KR102961822 B1KR 102961822B1KR-102961822-B1

Abstract

An electroluminescent (EL) sheet is provided. The sheet comprises a transparent electrode layer, a light-emitting layer, a dielectric layer, a back electrode layer, and an insulating layer formed sequentially on a transparent substrate, wherein the light-emitting layer comprises a binder; and zinc sulfide (ZnS)-based phosphors and rutile titanium dioxide ( TiO2 ) particles having an average particle size of 0.2 μm to 0.5 μm dispersed in the binder, wherein, based on 100 parts by weight of solid content in the light-emitting layer, the zinc sulfide-based phosphors comprise 55 parts by weight to 70 parts by weight and the titanium dioxide ( TiO2 ) particles comprise 3 parts by weight to 10 parts by weight.

Inventors

  • 정승복

Dates

Publication Date
20260507
Application Date
20251024

Claims (10)

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  7. Step of preparing fluorescent paste; A step of applying the prepared fluorescent paste onto a transparent substrate; and The method includes the step of curing the applied paste to form a light-emitting layer; The above light-emitting layer is, It comprises a binder and a zinc sulfide (ZnS)-based phosphor dispersed in the binder, and rutile titanium dioxide ( TiO2 ) particles having an average particle size of 0.2 μm to 0.5 μm, and Based on 100 parts by weight of solid content in the light-emitting layer, the zinc sulfide (ZnS)-based phosphor comprises 55 to 70 parts by weight, and the titanium dioxide ( TiO2 ) particles comprise 3 to 10 parts by weight. The step of applying on the transparent substrate is a step of applying the fluorescent paste on the transparent substrate having a transparent electrode layer using a screen printing method, and The method includes the step of sequentially forming a dielectric layer, a back electrode layer, and an insulating layer on the light-emitting layer after the step of forming the light-emitting layer, and The above screen printing method is, Using a screen of 180 mesh to 200 mesh, Performed under conditions of a squeegee angle of 70° to 80°, a pressure of 1.5 N/cm to 3.0 N/cm, and a velocity of 50 mm/s to 100 mm/s, Method for manufacturing an electroluminescent (EL) sheet.
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  10. Step of preparing fluorescent paste; A step of applying the prepared fluorescent paste onto a transparent substrate; and The method includes the step of curing the applied paste to form a light-emitting layer; The above light-emitting layer is, It comprises a binder and a zinc sulfide (ZnS)-based phosphor dispersed in the binder, and rutile titanium dioxide ( TiO2 ) particles having an average particle size of 0.2 μm to 0.5 μm, and Based on 100 parts by weight of solid content in the light-emitting layer, the zinc sulfide (ZnS)-based phosphor comprises 55 to 70 parts by weight, and the titanium dioxide ( TiO2 ) particles comprise 3 to 10 parts by weight. The step of forming the light-emitting layer above is, A drying step performed at 60℃ to 80℃ for 2 to 3 minutes; After the drying step above, a first curing step performed at 95°C to 105°C for 3 to 5 minutes; and A second curing step performed at 120°C to 150°C for 10 to 20 minutes after the first curing step; comprising Method for manufacturing an electroluminescent (EL) sheet.

Description

Electroluminescent (EL) Sheet and Method for Manufacturing the Same The present invention relates to an electroluminescent (EL) sheet and a method for manufacturing the same. More specifically, it relates to an electroluminescent (EL) sheet with improved brightness and luminescence uniformity and a method for manufacturing the same. Conventional electroluminescent (EL) sheets were generally manufactured by mixing zinc sulfide (ZnS)-based phosphors into a binder resin to form an emissive layer. However, these conventional emissive layers suffered from low light extraction efficiency from phosphor particles, making it difficult to secure sufficient luminous brightness. Furthermore, particularly when printing over large areas, controlling the physical properties of the paste was difficult, leading to a problem of reduced uniformity across the entire emissive surface. Furthermore, during prolonged operation, problems arose in which the luminescence characteristics deteriorated due to electrical stress applied to the light-emitting layer and external environmental factors. Specifically, the luminescence color became uneven or micro-cracks occurred on the surface, reducing visibility, which caused a decrease in the overall reliability of the product and a shortened lifespan. FIG. 1 is a cross-sectional structural diagram of an electroluminescent (EL) sheet according to one embodiment of the present invention. FIG. 2 is a schematic diagram showing a comparison of cross-sections of a light-emitting layer before and after the addition of titanium dioxide ( TiO2 ) particles according to one embodiment of the present invention. FIG. 3 is a schematic diagram showing a comparison of the effects according to the size of titanium dioxide ( TiO2 ) particles according to one embodiment of the present invention. FIG. 4 is a flowchart showing the manufacturing process of a fluorescent paste according to one embodiment of the present invention. FIG. 5 is a flowchart showing the printing and curing process of a light-emitting layer according to one embodiment of the present invention. The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. In this specification, "zinc sulfide-based phosphor" is used to refer to a phosphor powder in which ZnS is used as the host material and an activator, such as copper (Cu) or manganese (Mn), is doped. For example, 'ZnS:Cu' refers to a structural material in which Cu is doped into a ZnS host material. FIG. 1 is a cross-sectional structural diagram of an electroluminescent (EL) sheet according to one embodiment of the present invention. Referring to FIG. 1, an electroluminescent (EL) sheet (100) according to one embodiment of the present invention includes a structure in which a transparent electrode layer (20), a light-emitting layer (30), a dielectric layer (40), a rear electrode layer (50), and an insulating layer (60) are sequentially formed on a transparent substrate (10). The transparent substrate (10) serves to support the entire structure, and, for example, a polyethylene terephthalate (PET) film having high visible light transmittance and excellent flexibility may be used. The transparent electrode layer (20) is an electrode for applying an electric field to the light-emitting layer (30) and is formed from a material that is transparent and has excellent electrical conductivity, such as indium tin oxide (ITO). The rear electrode layer (50) is another electrode that applies an electric field to the light-emitting layer (30) together with the transparent electrode layer (20) and can be formed by printing silver (Ag) paste or carbon paste, etc. The dielectric layer (40) is positioned between the light-emitting layer (30) and the rear electrode layer (50) to prevent insulation breakdown and to efficiently concentrate the electric field on the light-emitting layer (30). It is typically formed by curing an insulating paste containing ceramic particles such as BaTiO3, which has a high dielectric constant. The insulating layer (60) serves as a protective layer that protects the entire device from external moisture or physical shock. The light-emitting layer (30), which is a core component of the present invention, is a layer that emits light on its own when an alternating electric field is applied, and has a structure in which zinc sulfide (ZnS)-based phosphor and titanium dioxide ( TiO2 ) particles are uniformly dispersed within a binder. The specific configuration of the