KR100976618B1 - An inorganic electro luminescence device - Google Patents

Abstract

The present invention relates to an inorganic EL device with improved brightness, and more particularly, emits light using UV wavelengths other than blue and blue, and absorbs a part of the light emitted from the light source to transfer to another wavelength and transmits the remaining light. Including inorganic photoluminescent phosphor that uses the wavelength of the light source, color can be realized by using UV as well as visible light to realize colors of various wavelengths. To provide.

High brightness, inorganic EL element, photoluminescent phosphor layer

Description

An inorganic electro luminescence device

The present invention relates to an inorganic EL device with improved luminance, and more particularly, to amplify the wavelength of the inorganic EL using a photoluminescent phosphor that emits light in the UV wavelength range as well as the wavelength of the visible light region rather than the light of the light source. The present invention relates to an inorganic EL element having a high luminance, thereby exhibiting a high luminance.

In general, EL (electro luminescence) is to apply a phosphor as a light emitting layer to a transparent organic or inorganic film or a linear structure, and then apply an alternating voltage to generate an electric field to cause light emission. That is, the electric field generated when the AC voltage is applied causes the phosphor to rapidly charge and discharge, and in this process, the electron movement is represented by light, which means EL, which is manufactured using this characteristic. It is an inorganic EL element.

That is, an electroluminescence device (hereinafter referred to as an EL element) is a self-luminous display element, which has a wide viewing angle, excellent contrast, and fast response time. An EL element is classified into an inorganic EL element and an organic EL element according to a material for forming an emitting layer.

The inorganic EL element is thin and light like paper, and is used in a device requiring uniform light emission such as a back light device of a display liquid crystal display device due to the characteristics of uniform surface light emission and easy manufacturing. do. In addition, it is generally applied to a keypad of a communication device such as a mobile phone, it is generally used as a device for performing the signal generation and other various additional functions of the keypad difficult to identify at night. In addition, the inorganic EL element is placed in front of the display film, such as advertising text, prop pictures, photographs, and the rear of the inorganic EL element after applying the power to emit light, the display film is transmitted through the light to display the backlight It is also used as.

Meanwhile, as shown in FIG. 1, the conventional inorganic EL device includes a transparent insulating film 10, a first electrode 30 made of ITO, an electroluminescent phosphor layer 40, a hole transport layer 50, and a second electrode layer ( 60), the protective layer 70 and the protective film 80 includes a stacked structure sequentially. In addition, as shown in FIG. 2, the transparent conductive film (coated first electrode) 12, the electroluminescent phosphor layer 40, the hole transport layer 50, the second electrode 60, and the protective layer 70. And a structure in which the protective film 80 is sequentially stacked.

The emission form of the inorganic EL device is determined by various causes, the biggest of which is the efficiency of the electroluminescent phosphor.

Since the inorganic EL has been invented, the efficiency of the phosphor has been increased. However, the efficiency of the electroluminescent phosphor itself is limited, and thus the development of the inorganic EL having high brightness is delayed. In particular, the electroluminescent phosphor capable of realizing a white color is not diverse, and dyes and color films are used, which has a problem of reducing lifetime and luminance.

The present invention, in order to overcome the problems of the inorganic EL device according to the prior art, by using an inorganic light emitting phosphor capable of emitting wavelengths in the UV region as well as visible light, improved luminance, various wavelengths, color purity, color rendering index and color It is an object of the present invention to provide an inorganic EL element having a high brightness and a display device using the same, which can improve luminance, such as improving the refresh rate.

In order to achieve the above object, the present invention is a photoluminescent phosphor layer;

A transparent insulating substrate formed on the photoluminescent phosphor layer;

A photoluminescent phosphor layer formed on or below the transparent insulating substrate;

A first electrode formed on the transparent insulating substrate;

An electroluminescent phosphor layer formed on the first electrode; And

Inorganic EL device comprising a second electrode formed on the electroluminescent phosphor layer,

The photoluminescent phosphor layer emits light using UV wavelengths other than blue and blue, absorbs a part of the light emitted from the light source, transitions to another wavelength, and transmits the remaining light.

The photoluminescent phosphor layer may comprise (Sr _2-xy Mg _x Ba _y ) SiO ₄ : Eu ²⁺ (where 0 ≦ _x ≦ 2 and 0 ≦ _y ≦ 2); (Sr _2-xy Ca _x Ba _y ) SiO ₄ : Eu ²⁺ (where 0 ≦ _x ≦ 2 and 0 ≦ _y ≦ 2); (Sr _1-x Ca _x ) Ga ₂ S _4: Eu ²⁺ (where 0 ≦ x ≦ 1); (Sr _1-x Mg _x ) Ga ₂ S _4: Eu ²⁺ (where 0 ≦ x ≦ 1); CaS: Eu ²⁺ ; SrS: Eu ²⁺ ; (Ca _x Sr _y ) S: Eu ²⁺ (where x + y = 1, 0 ≦ x ≦ 1, 0 ≦ y ≦ 1); MgS: Eu; ZnS: Eu; ZnS: Cu, Al; And an inorganic phosphor selected from the group consisting of CaS: Pb.

The present invention also provides a transparent insulating substrate;

A photoluminescent phosphor layer formed on the transparent insulating substrate;

A first electrode formed on the photoluminescent phosphor layer;

An electroluminescent phosphor layer formed on the first electrode; And

Inorganic EL device comprising a second electrode formed on the electroluminescent phosphor layer,

The photoluminescent phosphor layer emits light using UV wavelengths other than blue and blue, absorbs a part of the light emitted from the light source, transitions to another wavelength, and transmits the remaining light.

The photoluminescent phosphor layer may comprise (Sr _2-xy Mg _x Ba _y ) SiO ₄ : Eu ²⁺ (where 0 ≦ _x ≦ 2 and 0 ≦ _y ≦ 2); (Sr _2-xy Ca _x Ba _y ) SiO ₄ : Eu ²⁺ (where 0 ≦ _x ≦ 2 and 0 ≦ _y ≦ 2); (Sr _1-x Ca _x ) Ga ₂ S _4: Eu ²⁺ (where 0 ≦ x ≦ 1); (Sr _1-x Mg _x ) Ga ₂ S _4: Eu ²⁺ (where 0 ≦ x ≦ 1); CaS: Eu ²⁺ ; SrS: Eu ²⁺ ; (Ca _x Sr _y ) S: Eu ²⁺ (where x + y = 1, 0 ≦ x ≦ 1, 0 ≦ y ≦ 1); MgS: Eu; ZnS: Eu; ZnS: Cu, Al; And CaS: Pb, which provides one or more inorganic phosphors selected from the group consisting of.

In addition, the present invention provides a display device including the inorganic EL element having the high brightness. The device may be an illumination display device or a backlight device for liquid crystal display.

Hereinafter, the present invention will be described in detail.

The present invention is to construct an inorganic EL element by using a phosphor that induces photoluminescence in a conventional inorganic EL element, and the phosphor includes a light emitting phosphor that emits light using UV wavelengths other than blue and blue. In addition, the photoluminescent phosphor partially absorbs light from a light source and transitions to another wavelength, and transmits the remaining light.

That is, according to the present invention, since the photoluminescent phosphor layer absorbs a part of the wavelength emitted from the electroluminescent phosphor layer to implement white light, it is possible to display high luminance and improve color purity without using a filter such as a dye and a color film. Can be.

In addition, although the conventional inorganic EL device was able to emit light using only visible light such as blue light, the present invention electroluminescent not only visible light such as blue light, but also using an inorganic phosphor that emits UV light. It is possible to provide an inorganic EL element capable of more various colors.

In addition, the blue light emission must be used in the prior art, but there was a limitation in efficiency and color implementation in implementing the color of the EL. However, when the UV of the present invention is used, various color implementations are possible. And, simultaneously emitting blue and UV light as in the present invention improves both efficiency and color implementation.

The inorganic EL device of the present invention comprises a photoluminescent phosphor layer; A transparent insulating substrate formed on the photoluminescent phosphor layer; A first electrode formed on the transparent insulating substrate; An electroluminescent phosphor layer formed on the first electrode; And a second electrode formed on the electroluminescent phosphor layer. In this case, the first electrode may be a transparent conductive film coated with a conductive material on a transparent insulating substrate. Accordingly, the transparent insulating substrate and the first electrode may be formed on one layer on the photoluminescent phosphor layer.

In addition, the inorganic EL element of the present invention comprises a transparent insulating substrate; A photoluminescent phosphor layer formed on the transparent insulating substrate; A first electrode formed on the photoluminescent phosphor layer; An electroluminescent phosphor layer formed on the first electrode; And a second electrode formed on the electroluminescent phosphor layer.

In addition, the inorganic EL device of the present invention may further include a hole transport layer between the electroluminescent phosphor layer and the second electrode. The present invention may further include a first electrode between the photoluminescent phosphor layer and the electroluminescent phosphor layer formed on the transparent substrate. The inorganic EL device may further include an insulating-oxidation protective layer and a protective film on the second electrode. The photoluminescent phosphor layer formed under the transparent substrate may further include a protective film on the rear surface. In addition, the protective film in the present invention may further include a conventional encapsulation film that can prevent the penetration of moisture or oxygen.

In the present invention, the photoluminescent phosphor layer constituting the inorganic EL element may be configured in the form of a sheet, a film, or a plate, and preferably may be manufactured and used in the form of a sheet. The method of forming the photoluminescent phosphor layer is not particularly limited, but may be performed by, for example, a screen printing method using a paste composition.

In particular, the phosphor used in the photoluminescent phosphor layer of the present invention emits light using UV wavelengths other than blue and non-blue wavelengths, partially absorbs the light emitted from the light source and transfers it to other wavelengths, and transmits the remaining light. do. The photoluminescent phosphor exhibiting the above characteristics is characterized in that the inorganic phosphor. Inorganic phosphors used in the present invention are higher in brightness than organic phosphors or nano phosphors, have excellent reliability, are suitable for long-term use, are stable to heat and humidity, and can emit UV wavelengths as well as visible light such as blue.

The inorganic fluorescent material _{(Sr 2 -x- y Ca x Ba} y) SiO 4: Eu 2 + ( However, 0≤x≤2, 0≤y≤2); (Sr _{2 -xy} Mg _x Ba _y ) SiO ₄ : Eu ²⁺ (where 0 ≦ _x ≦ 2 and 0 ≦ _y ≦ 2); _{(Sr 1 - x Ca x)} Ga 2 S 4: Eu 2 + ( However, 0≤x≤1); _{(Sr 1 - x Mg x)} Ga 2 S 4: Eu 2 + ( However, 0≤x≤1); CaS: Eu ^{2 +;} SrS: Eu ^{2 +;} _{(Ca x Sr y) S:} Eu 2 + ( stage, x + y = 1, 0≤x≤1 , 0≤y≤1); MgS: Eu; ZnS: Eu; And ZnS: Cu, Al, and CaS: Pb, or one or two or more inorganic crystal mixed phosphors selected from the group consisting of. When the two kinds of phosphors are mixed, for example, a blue phosphor and a green phosphor or a blue phosphor and a red phosphor may be mixed, and the ratio may be 1: 9 to 9: 1.

Since the emission spectra of the inorganic phosphors are different from each other, the present invention implements a variety of high brightness by making a mixture of light using such a spectrum. In _{particular, SiO 4 (Sr 2 -x- y} Ca x Ba y): Eu 2 + In the case of the fluorescent material absorbs the blue light emitted from the electroluminescent phosphor layer to emit yellow light emission of about 550nm. Using the fluorescent material, the sheet is printed on the bottom of the upper side of the substrate to produce a sheet of inorganic EL, which can realize high brightness white color. G. A preferred example of a phosphor used for the light-emitting phosphor layer in the present ^{_{invention, Sr 2 SiO 4: Eu 2+}} , SrBaSiO 4: Eu 2 +, Sr 1 Ga 2 S 4: Eu 2 +, CaS: Eu 2 + , etc. There is this. In addition, CaS: Pb is more preferably used as the phosphor having a wavelength in the UV region among the inorganic phosphors. The CaS: Pb phosphor is electroluminescent in an inorganic EL device and emits UV in a 365 nm region, and in this case, color can be realized through visible light variation similar to blue light emission. In addition, when the blue phosphor layer is formed between the hole transport layer and the electron transport layer, that is, when the blue phosphor layer is located at a position related to electroluminescence, the blue phosphor layer is deteriorated in brightness and reliability under the influence of current. Therefore, it is effective to make the phosphor layer have a separate layer to emit light.

In this case, the transparent substrate may be selected from the group consisting of a transparent insulating film and a transparent conductive film.

The transparent insulating film may be a plastic film such as transparent glass or PET without conductivity. Specifically, the resin used in the production of the transparent insulating substrate film in the present invention is epoxy, polyethylene, urethane, polyester, polyvinyl chloride, polycarbonate, acrylic, vinyl, fluororesin, polypropylene , ABS, CBS, polymethyl methacrylate, methacrylic ester, polyvinyl chloride, synthetic rubber and the like.

The first electrode may include a transparent conductive film coated with a conductive material on a transparent insulating substrate. That is, the transparent conductive film is prepared by coating the resin with a film, and then coating the conductive material with a thin film and a thick film on the top and bottom of the film by a physical-chemical method, and the type thereof is not particularly limited. For example, the transparent conductive film may be coated with a conductive material of a transparent material such as indium tin oxide (ITO), indium zinc oxide (IZO), and antimony tin oxide (ATO).

When the photoluminescent phosphor layer is formed on the transparent substrate, it is preferable to use a transparent insulating substrate as the substrate. When the photoluminescent phosphor layer is formed below the transparent substrate, it is preferable to use a transparent conductive film as the substrate.

The electroluminescent phosphor layer may be formed in a predetermined pattern on the first electrode. In addition, the electroluminescent phosphor layer can be used both of the surface of the phosphor used in the electroluminescent layer of the ordinary EL element. Preferably, the electroluminescent phosphor uses a blue light emitting phosphor having a maximal emission wavelength in a wavelength band of at least 400 to 500 nm, and more preferably, a phosphor emitting light of 450 to 460 nm, wherein ZnS: Ag, ZnS : Cu, Al, SrGaS: Eu, etc. can be used, and in particular, ZnS: Cu, Al can be used.

The second electrode is a cathode, and includes a conductive polymer, Ag-based or carbon-based, for example, metal oxides such as metals such as aluminum, gold, silver, nickel, palladium, platinum, and oxides of indium and / or tin. And metals such as copper iodide, halogenated metals, carbon black, or conductive polymers such as poly (3-methylthiophene), polypyrrole, and polyaniline can be formed in a predetermined pattern by a method well known in the art. . For example, the second electrode layer may be formed by sputtering, vacuum deposition, screen printing, or the like.

The hole transport layer is a dielectric layer that assists the transport of holes from the first electrode to the electroluminescent phosphor layer. The brightness and stability of the overall inorganic EL device also depend on the thickness of the dielectric layer, the size of the dielectric powder, the resin and the solvent used, and the like. These appear differently and can be formed by methods well known to those skilled in the art and are not particularly limited. For example, the hole transport layer may be formed by applying a liquid material obtained by dispersing or dissolving a dielectric powder such as BaTiO ₃ and an insulating organic material in a solvent, or by heating and drying the electroluminescent phosphor layer. Examples of the organic material include 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl, 4,4 ', 4''-tris (1-naphthylphenylamino) triphenylamine And spiro compounds such as 2,2 ', 7,7'-tetrakis- (diphenylamino) -9,9'-spirobifluorene, polyvinylcarbazole, polyvinyltriphenylamine and tetraphenylbenzidine Materials, such as polyarylene ether sulfone and polyvinylidene fluoride, are mentioned. The hole transport layer of the present invention as described above may include BaTiO ₃ .

The first electrode layer is an anode electrode and may be formed in a predetermined pattern on the photoluminescent phosphor layer by using a transparent conductive material selected from the group consisting of ITO, indium zinc oxide (IZO), and antimony tin oxide (ATO). have.

The insulating-oxidation protective layer may be used as long as it is a metal oxide-based material. Typically, MgSiO ₂ is used, which serves to insulate the electrode layer, increase moisture resistance of the inorganic EL element, and reduce oxidation. It can be formed using glass or ordinary plastics with a high refractive index. For example, plastics may have a refractive index of 1.6 or more and a light transmittance of 90% or more, and may be PC, PET, PP, or the like.

The protective film may be used as long as it is a material capable of preventing the penetration of moisture and finally passivating the device, and the kind and formation method thereof are not particularly limited. For example, the protective film can use a transparent insulating film, such as a polyethylene film, a polypropylene film, an acryl type, an epoxy type, and a silicone type compound.

In the present invention, the method for forming the first electrode layer and the second electrode layer is sputtering, electron beam deposition, ion beam assisted deposition (IBAD), chemical vapor deposition (CVD), and sol-gel (sol-gel). ), Screen printing, or the like.

In addition, in the present invention, the film thickness of the photoluminescent and electroluminescent fluorescent layers is not particularly limited, but if the thickness is too thick, the driving voltage is increased, and if the thickness is too thin, the luminous efficiency is lowered. It is good.

Hereinafter, with reference to the drawings will be described in detail with respect to the configuration of the inorganic EL according to an embodiment of the present invention and its manufacturing method. However, this is presented by way of example, whereby the present invention is not limited and the present invention is defined only by the scope of the claims to be described later.

3 is a cross-sectional view of an inorganic EL device having improved luminance using a transparent insulating substrate and a photoluminescent phosphor layer according to a first embodiment of the present invention.

As shown in FIG. 3, the inorganic EL element having high brightness according to the present invention includes a transparent insulating substrate 10 and a photoluminescent phosphor layer 20 formed thereon; A first electrode layer 30 formed on the photoluminescent phosphor layer; An electroluminescent phosphor layer 40 formed on the first electrode layer; A hole transport layer (dielectric layer) 50 formed on the electroluminescent phosphor layer; A second electrode layer 60 formed on the hole transport layer; An insulating-oxidation protection layer 70 formed on the second electrode layer; And a protective film 80 formed on the protective layer.

The manufacturing method of the inorganic EL device is not particularly limited and may be made by a method in the art to which the present invention belongs. For example, the above-described transparent insulating substrate 10 is prepared, the photoluminescent phosphor layer 20 is formed by using a photoluminescent phosphor paste in a predetermined pattern thereon, and the hole transport layer 50 is formed using an organic insulating material. ) Is formed in a predetermined pattern, the second electrode layer 60 is formed of a metal material such as aluminum, and the protective film 90 is formed by a method of encapsulation after forming the protective layer 70.

In this case, when the first electrode layer is formed, the photoluminescent phosphor layer should be formed on the transparent insulating substrate. Therefore, it is preferable to print and stack the photoluminescent phosphor layer on the transparent insulating substrate before printing the first electrode layer. The paste includes a photoluminescent phosphor material, a binder resin, and a solvent, and the mixing ratio thereof is not particularly limited.

The photoluminescent phosphor paste includes an inorganic photoluminescent phosphor, a binder resin, and a solvent having a UV wavelength other than the blue color and the blue color, and the polymer and solvent for the binder resin used therein are commonly used in the art. Since it can be selected from those, it does not specifically limit, For example, ECA, BCA, DMAC etc. can be used as a binder resin, Ethanol, acetone, ether, an organic solvent, etc. can be used as a solvent.

In addition, the first electrode layer may be deposited by a sputtering method using ITO or the like.

The electroluminescent phosphor layer may be formed by a screen printing method using a paste containing a conventional blue light emitting phosphor, a binder resin, and a solvent. As the blue light emitting phosphor, ZnS: Cu, Al, SrGaS: Eu, or the like may be used. In addition, ECA, BCA, DMAC, etc. may be used as the binder resin. The solvent may be ethanol, acetone, ether, an organic solvent and the like.

The hole transport layer 50 may be formed by a screen printing method using a paste containing BaTiO ₃ and an additive as a piezoelectric polymer, a solvent, and a dielectric powder.

The second electrode layer 60 may be formed by a sputtering method or a vacuum deposition method using a metal such as aluminum.

The protective layer 70 is an insulating-oxidation protective layer, and may be formed using MgSiO ₂ or the like.

The protective film 80 may be formed using a polyethylene film, a polypropylene film, or the like.

4 is a cross-sectional view of an inorganic EL device having improved luminance using a transparent conductive substrate and a photoluminescent phosphor layer according to a second embodiment of the present invention.

As shown in FIG. 4, the inorganic EL element having the high brightness of the present invention includes a transparent conductive film 12; A photoluminescent phosphor layer 20 formed at a lower portion thereof; A protective film 80 formed on the rear surface of the photoluminescent phosphor layer; An electroluminescent phosphor layer 40 formed on the transparent conductive film 12; A hole transport layer (dielectric layer) 50 formed on the electroluminescent phosphor layer; A second electrode layer 60 formed on the hole transport layer; A protective layer 70 formed on the second electrode layer; And it may be configured to include a protective film 80 formed on the protective layer. In this case, the transparent conductive film includes a first electrode formed on the transparent insulating substrate, and the transparent insulating substrate and the first electrode may be formed on one layer on the photoluminescent phosphor layer.

The inorganic EL device manufacturing method is also not particularly limited, and the transparent insulating film 12 coated with the first electrode, which is a conductive material, is used for the transparent insulating substrate 10, and a photoluminescent phosphor paste is disposed thereunder. The hole transport layer 50 is formed, except that the photoluminescent phosphor layer 20 and the protective film 80 formed on the rear surface of the photoluminescent phosphor layer 20 are formed and the electroluminescent phosphor layer is formed on the transparent insulating substrate 12. The method of forming the second electrode layer 60, the protective layer 70, and the protective film 80 is as described above.

In the present invention, the thickness of each layer constituting the inorganic EL element is not particularly limited, and may be manufactured in a conventional thickness range in the art to which the present invention belongs.

In addition, the present invention provides a display device including an inorganic EL element having high luminance capable of implementing various wavelengths and improving color purity and luminance. The device may be an illumination display device or a backlight device for liquid crystal display. Since the display device structure described above is well known in the art and can be sufficiently understood by those in the art, detailed description thereof will be omitted.

The present invention can overcome the disadvantages of the conventional inorganic EL element using the photoluminescent phosphor and can implement the color using the visible light and UV wavelength can provide an inorganic EL element having a high brightness significantly improved brightness.

In particular, according to the present invention it is possible to implement a high brightness by the effect of amplification and diffusion of light using the photoluminescent phosphor in the form of a sheet.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the following examples are only intended to illustrate the present invention, and the protection scope of the present invention is not intended to be limited to the following examples.

Comparative Example 1

As shown in FIG. 1, the first electrode layer 30, the electroluminescent phosphor layer 40, the hole transport layer 50, the second electrode layer 60, A conventional inorganic EL device including a protective layer 70 and a protective film 80 was manufactured.

At this time, the transparent insulating film was used polyethylene terephthalate (PET). (Fig. 1-PET (transparent insulating film), ITO coated transparent conductive film)

As the electroluminescent phosphor layer, a ZnS: Cu, Al phosphor showing blue light emission at 455 nm was used.

Comparative Example 2

In Comparative Example 1, the electroluminescent phosphor layer 40, the hole transport layer 50, and the second electrode layer 60 shown in FIG. 2 are used as a substrate by using the transparent conductive film 12 as a substrate instead of the transparent insulating film. The conventional inorganic EL device including the protective layer 70 and the protective film 80 was manufactured. In this case, the transparent conductive film was a polyethylene film (coated first electrode) on which ITO was deposited. (Fig. 2-Thermoplastic-Polyurethane (TPU) (transparent insulating film))

Example 1

Using transparent insulation board EL element  Produce

As shown in FIG. 3, the photoluminescent phosphor layer 20, the first electrode layer 30, the electroluminescent phosphor layer 40, the hole transport layer 50, and the second electrode layer 60 are sequentially disposed on the transparent insulating substrate 10. ), An insulation-oxidation protective layer 70, and a protective film 80 were formed to manufacture an inorganic EL device.

That is, a screen including a paste containing an inorganic fluorescent material on a polyethylene terephthalate and a polyurethane transparent insulating substrate 10 having a thickness of 100 to 150 μm, and dried at 130 to 150 ° C., a photoluminescent phosphor layer having a thickness of 20 to 50 μm. (20) was formed. At this time, the paste is an inorganic fluorescent material Sr ₂ SiO ₄ : Eu ^{2 +} , a mixed resin of ECA (diethylene glycol monoethyl ether acetate) and BCA (diethylene glycol butyl ether acetate) as a binder resin and a mixed solvent of ethanol and acetone as a solvent Was prepared to contain a weight ratio of 50:35:15.

Subsequently, ITO was deposited on the photoluminescent phosphor layer 20 by a sputtering method to form a first electrode layer 30.

After formation of the first electrode layer 30, a blue light emitting phosphor ZnS: Cu, Al, a binder resin diethylene glycol monoethyl ether acetate (ECA), a diethylene glycol butyl ether acetate (BCA) mixed resin, and a solvent of ethanol and acetone A paste containing a mixed solvent in a weight ratio of 50:35:15 was applied and dried to form an electroluminescent fluorescent layer 40.

Then, a polyvinylidene fluoride, cyclohexanone as a solvent, dielectric powder BaTiO ₃ and a paste containing a resin were applied to the electroluminescent layer 40 and dried to form a hole transport layer 50. .

Thereafter, aluminum is printed on the hole transport layer 50 by screen printing to form a second electrode layer 60, and MgSiO ₂ An inorganic EL device was manufactured by sequentially forming a protective layer 70 of a raw material and a transparent protective film 80 of polypropylene.

[Example 2]

Transparent conductive substrate  Used EL  device

As shown in FIG. 4, a photoluminescent phosphor layer 20 is formed below the transparent conductive film 12, a protective film 80 is formed on the rear surface thereof, and electroluminescence is sequentially performed on the transparent conductive film 12. An inorganic EL device was manufactured by forming the phosphor layer 40, the hole transport layer 50, the second electrode layer 60, the insulation-oxidation protective layer 70, and the protective film 80.

That is, a screen containing a paste containing an inorganic fluorescent material on the polyethylene terephthalate transparent conductive substrate 12 having ITO deposited thereon with a thickness of 100 μm is dried and dried at 130 to 150 ° C. to form a photoluminescent phosphor layer having a thickness of 20 to 50 μm ( 20) was formed. At this time, the paste is the same as in Example 1.

Then, the protective film 80 of the transparent polymer-based on the photoluminescent phosphor layer 20 was formed.

Subsequently, the electroluminescent phosphor layer 40 was formed on the transparent conductive substrate 12 using the blue light emitting phosphor paste of Example 1.

Thereafter, in the same manner as in Example 1, the hole transport layer 50, the second electrode layer 60, the protective layer 70, and the protective film 80 are sequentially formed on the electroluminescent layer 40. The device was manufactured.

Example 3

Except for using SrBaSiO ₄ : Eu ^{2 +} as the phosphor used for the photoluminescent phosphor layer 20, it was carried out in the same manner as in Example 1.

Example 4

A phosphor used in the light-emitting phosphor layer _{(20) Sr 1 Ga 2 S} 4: was carried out in the same manner as in Example 1, except for using Eu ^{+ 2.}

Example 5

Except for using CaS: Eu ^{2 +} as the phosphor used for the photoluminescent phosphor layer 20, it was carried out in the same manner as in Example 2.

Experimental Example 1

Comparative experiments were performed on the inorganic EL devices of Comparative Example 1 and Examples 1 to 5, and the results are shown in FIGS. 5 and 6.

FIG. 5 compares the emission spectrum of the inorganic EL device of Comparative Example 1 and the white inorganic EL device to which the phosphor sheet of Example 1 is applied.

In addition, Figure 6 shows a comparison of changes in the emission spectrum of Comparative Example 1 and Examples 2 to 5 in which various kinds of phosphor sheets were applied to the inorganic EL. That is, the phosphor of Comparative Example 1 (EL sheet), Example _{2 (Sr 2 SiO 4: Eu} 2 +, EL sheet + green phosphor _{I (Sr 2 SiO 4: Eu} 2 +)) in the sequence in Figure 6, the embodiment ^{_{3 (SrBaSiO 4: Eu 2+,}} EL sheet + green phosphor ^{_{II (SrBaSiO 4: Eu 2+)}} ), example _{4 (Sr 1 Ga 2 S 4} : Eu 2 +, EL sheet + green phosphor III (Sr ₁ Ga ₂ S _4: ^{Eu 2 +)): Eu 2+} )), example ^{5 (CaS: Eu 2 +,} EL sheet + red phosphor (CaS.

Inorganic EL devices of Comparative Examples 1 and 2 through the prior art showed a luminance of up to 70 cd / m 2.

In addition, in general, when applied to a display, since the inorganic EL element of the white light should be manufactured, the color change is shown using a dye and a color film, in this case, Comparative Examples 1 and 2 have a luminance of up to 50 cd / m 2. The brightness was reduced.

On the other hand, Examples 1 and 2 have a high luminance of 200 cd / m 2 by using an inorganic photoluminescent phosphor that can absorb a portion of the emitted light in an inorganic or organic EL element having a wavelength other than blue or blue and transition to another wavelength. Indicated. Through these results, the present invention can implement various wavelengths, and it is possible to provide an inorganic EL device having high luminance by improving color purity and improving luminance.

Example 6

A phosphor used in the light-emitting phosphor layer (20) CaS: were prepared inorganic ELK sheet in the same manner as in Example 1 except that the Pb ^{2 +} phosphor. Then, the optical properties were confirmed, and the emission spectrum results are shown in FIG. 7. As shown in Figure 7, CaS: Pb ^{2 +} phosphor has a main peak in the UV emission was of 3.37eV, namely 362.5nm.

Example 7

The phosphor used for the photoluminescent phosphor layer 20 is a blue (SrMg) ₂ SiO ₄ : Eu phosphor, a green Ba ₂ SiO ₄ : Eu ^{2 +} phosphor, and a yellow Sr ₂ SiO ₄ : Eu phosphor. An inorganic EL sheet was produced in the same manner as in Example 1, except that the mixture was used in a ratio of 2. Then, the optical properties were confirmed, and the spectral results are shown in FIG. 8. As shown in FIG. 8, it can be seen that when the mixed phosphor is included, blue-yellow-yellow mixed white is emitted from the photoluminescent phosphor layer 20 by absorbing the UV region emitting from the sheet.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and a person skilled in the art does not depart from the spirit and scope of the present invention described in the above-described range and the appended claims. It will be appreciated that various changes and modifications can be made within the scope of the invention.

1 is a cross-sectional view of a general inorganic EL device of Comparative Example 1. FIG.

2 is a sectional view of a general inorganic EL device of Comparative Example 2. FIG.

3 is a sectional view of an inorganic EL device according to Embodiment 1 of the present invention.

Figure 4 shows a cross-sectional view of the inorganic EL device according to a second embodiment of the present invention.

FIG. 5 shows a comparison of emission spectra of the inorganic EL device of Comparative Example 1 and the white inorganic EL device to which the phosphor sheet is applied.

FIG. 6 shows a comparison of changes in emission spectra of Comparative Example 1 and Examples 2 to 5 in which various kinds of phosphor sheets are applied to inorganic EL.

Figure 7 shows the emission spectrum of the inorganic EL device of Example 6 of the present invention.

8 shows light emission spectrum results of the inorganic EL device of Example 7 of the present invention.

<Description of the symbols for the main parts of the drawings>

10: transparent insulation film

12: transparent conductive film (transparent insulating substrate coated with a first electrode)

20: photoluminescent phosphor layer

30: first electrode

40: electroluminescent phosphor layer

50: hole transport layer (dielectric layer)

60: second electrode 70: protective layer 80: protective film

Claims (28)

A photoluminescent phosphor layer; A transparent insulating substrate formed on the photoluminescent phosphor layer; A first electrode formed on the transparent insulating substrate; An electroluminescent phosphor layer formed on the first electrode; And Inorganic EL device comprising a second electrode formed on the electroluminescent phosphor layer, The photoluminescent phosphor layer emits light using UV wavelengths other than blue and blue, absorbs a part of the light emitted from the light source, transitions to another wavelength, and transmits the remaining light. The photoluminescent phosphor layer may comprise (Sr _2-xy Mg _x Ba _y ) SiO ₄ : Eu ²⁺ (where 0 ≦ _x ≦ 2 and 0 ≦ _y ≦ 2); (Sr _2-xy Ca _x Ba _y ) SiO ₄ : Eu ²⁺ (where 0 ≦ _x ≦ 2 and 0 ≦ _y ≦ 2); (Sr _1-x Ca _x ) Ga ₂ S _4: Eu ²⁺ (where 0 ≦ x ≦ 1); (Sr _1-x Mg _x ) Ga ₂ S _4: Eu ²⁺ (where 0 ≦ x ≦ 1); CaS: Eu ²⁺ ; SrS: Eu ²⁺ ; (Ca _x Sr _y ) S: Eu ²⁺ (where x + y = 1, 0 ≦ x ≦ 1, 0 ≦ y ≦ 1); MgS: Eu; ZnS: Eu; ZnS: Cu, Al; And one or more inorganic phosphors selected from the group consisting of CaS: Pb. The inorganic EL device according to claim 1, wherein the phosphor that emits UV wavelengths is CaS: Pb. The inorganic EL device of claim 1, wherein the first electrode comprises a transparent conductive film coated with a conductive material on a transparent insulating substrate. The inorganic EL device of claim 1, further comprising a hole transport layer between the electroluminescent phosphor layer and the second electrode. The inorganic EL device of claim 1, wherein the inorganic EL device further comprises an insulating-oxidation protective layer and a protective film on the second electrode. The inorganic EL device of claim 1, wherein the photoluminescent phosphor layer formed under the transparent substrate further includes a protective film on a rear surface thereof. The inorganic EL element according to claim 1, wherein the transparent substrate is selected from the group consisting of a transparent insulating film and a transparent conductive film. The inorganic EL device according to claim 1, wherein the electroluminescent phosphor layer comprises a blue light emitting phosphor selected from ZnS: Ag, ZnS: Cu, Al, and SrGaS: Eu. The inorganic EL device according to claim 1, wherein the second electrode is a conductive polymer, Ag-based or carbon-based. The inorganic EL device of claim 4, wherein the hole transport layer is a dielectric material comprising BaTiO ₃ . The inorganic EL device of claim 3, wherein the first electrode comprises a conductive material selected from the group consisting of indium tin oxide (ITO), indium zinc oxide (IZO), and antimony tin oxide (ATO). The inorganic EL device according to claim 5, wherein the insulation-oxidation protective layer is a metal oxide compound including MgSiO ₂ . The inorganic EL element according to claim 5 or 6, wherein the protective film is a transparent insulating film selected from the group consisting of polyethylene film, polypropylene film, acrylic, epoxy and silicone compounds. A transparent insulating substrate; A photoluminescent phosphor layer formed on the transparent insulating substrate; A first electrode formed on the photoluminescent phosphor layer; An electroluminescent phosphor layer formed on the first electrode; And Inorganic EL device comprising a second electrode formed on the electroluminescent phosphor layer, The photoluminescent phosphor layer emits light using UV wavelengths other than blue and blue, absorbs a part of the light emitted from the light source, transitions to another wavelength, and transmits the remaining light. The photoluminescent phosphor layer may comprise (Sr _2-xy Mg _x Ba _y ) SiO ₄ : Eu ²⁺ (where 0 ≦ _x ≦ 2 and 0 ≦ _y ≦ 2); (Sr _2-xy Ca _x Ba _y ) SiO ₄ : Eu ²⁺ (where 0 ≦ _x ≦ 2 and 0 ≦ _y ≦ 2); (Sr _1-x Ca _x ) Ga ₂ S _4: Eu ²⁺ (where 0 ≦ x ≦ 1); (Sr _1-x Mg _x ) Ga ₂ S _4: Eu ²⁺ (where 0 ≦ x ≦ 1); CaS: Eu ²⁺ ; SrS: Eu ²⁺ ; (Ca _x Sr _y ) S: Eu ²⁺ (where x + y = 1, 0 ≦ x ≦ 1, 0 ≦ y ≦ 1); MgS: Eu; ZnS: Eu; ZnS: Cu, Al; And one or more inorganic phosphors selected from the group consisting of CaS: Pb. The inorganic EL device according to claim 14, wherein the phosphor that emits UV wavelengths is CaS: Pb. The inorganic EL device of claim 14, wherein the first electrode comprises a transparent conductive film coated with a conductive material on a transparent insulating substrate. 15. The inorganic EL device of claim 14, further comprising a hole transport layer between the electroluminescent phosphor layer and the second electrode. 15. The inorganic EL device of claim 14, wherein the inorganic EL device further comprises an insulating-oxidation protective layer and a protective film on the second electrode. The inorganic EL device of claim 14, wherein the photoluminescent phosphor layer formed under the transparent substrate further includes a protective film on a rear surface thereof. The inorganic EL element according to claim 14, wherein the transparent substrate is selected from the group consisting of a transparent insulating film and a transparent conductive film. 15. The inorganic EL device according to claim 14, wherein the electroluminescent phosphor layer comprises a blue light emitting phosphor selected from ZnS: Ag, ZnS: Cu, Al, and SrGaS: Eu. 15. The inorganic EL device according to claim 14, wherein the second electrode is a conductive polymer, Ag-based or carbon-based. 18. The inorganic EL device of claim 17 wherein the hole transport layer is a dielectric material comprising BaTiO ₃ . The inorganic EL device of claim 16, wherein the first electrode comprises a conductive material selected from the group consisting of indium tin oxide (ITO), indium zinc oxide (IZO), and antimony tin oxide (ATO). 19. The inorganic EL device according to claim 18, wherein the insulation-oxidation protective layer is a metal oxide based compound comprising MgSiO ₂ . 20. The inorganic EL device according to claim 18 or 19, wherein the protective film is a transparent insulating film selected from the group consisting of polyethylene film, polypropylene film, acrylic, epoxy and silicone compounds. A display device comprising the inorganic EL element according to claim 1. The display device according to claim 27, which is an illumination display device or a backlight device for liquid crystal display.

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