JP2002110351A - Laminated phosphor and el panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated phosphor and an EL panel that does not require filter and has a good color purity and is, particularly, suitable for a white monochromatic electroluminescence. SOLUTION: This is a laminated phosphor having at least a first film 2 and a second film 4, and the base material of the first film is mainly composed of barium aluminate and contains sulfur element 0.02-0.5 mol% of S/(S+O) of the base material. And further the laminated phosphor contains Eu as a luminous core and the base material of the second film is mainly composed of zinc sulfide. The combination color of the emitted light of the first film and the second film is a white color of x=0.27-0.39, y=0.27-0.38 in the CIE chromaticity coordinates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting layer used for an inorganic EL device, and more particularly to a laminate of a white phosphor thin film used for a light emitting layer and an EL panel using the same.

[0002]

2. Description of the Related Art In recent years, thin-film EL devices have been actively studied as small, large, and lightweight flat displays. A monochrome thin-film EL display using a phosphor thin film made of manganese-doped zinc sulfide that emits yellow-orange light has already been put to practical use in a double insulating structure using thin insulating layers 2 and 4 as shown in FIG. In FIG. 2, a lower electrode 5 having a predetermined pattern is formed on a substrate 1, and a first insulating layer 2 is formed on the lower electrode 5. A light emitting layer 3 and a second insulating layer 4 are sequentially formed on the first insulating layer 2, and a matrix circuit with the lower electrode 5 is formed on the second insulating layer 4. Upper electrode 6 is formed in a predetermined pattern.

[0003] Furthermore, as a display for personal computers,
Colorization is indispensable for TVs and other displays. The thin-film EL display using the sulfide phosphor thin film is excellent in reliability and environmental resistance. However, at present, the characteristics of the EL phosphor emitting in the three primary colors of red, green and blue are not sufficient. Are unsuitable for color applications. The blue light emitting phosphor is Sr as a base material.
S, SrS using Ce as an emission center: Ce or Zn
S: Tm, ZnS: Sm, Ca
S: Eu, green light emitting phosphors: ZnS: Tb, Ca
S: Ce is a candidate and research is ongoing.

[0004] These phosphor thin films which emit light in the three primary colors of red, green and blue have problems in light emission luminance, efficiency and color purity, and color EL panels have not been put to practical use at present. In particular, for blue, relatively high luminance is obtained using SrS: Ce, but for blue for full-color display, luminance is insufficient and chromaticity is shifted to the green side. Development of a good blue light emitting layer is desired.

In order to solve these problems, Japanese Patent Laid-Open No.
122364, JP-A-8-134440,
As described in IEICE EID 98-113, pp. 19-24, and Jpn. J. Appl. Phys. Vol. 38, (1999) pp. L1291-1292, SrGa ₂ S ₄ : Ce, CaG
a ₂ S _4: Ce and, BaAl ₂ S _4: thiogallate or thioaluminate based blue phosphors such as Eu have been developed. These thiogallate-based phosphors have no problem in terms of color purity, but have low luminance, and particularly have a multi-component composition, so that it is difficult to obtain a thin film having a uniform composition. It is considered that a high-quality thin film cannot be obtained due to poor crystallinity due to poor composition controllability, generation of defects due to sulfur removal, contamination with impurities, and the like, so that the luminance does not increase. In particular, thioaluminate is extremely difficult to control the composition.

On the other hand, in a monochrome display,
It has already been commercialized using the orange phosphor ZnS: Mn. Considering the legibility of the display, there is a demand for a white monocolor. In response to this request, Display and Imaging, (1994) Vol. 3, 159-17
As shown on page 1, various white phosphors are being studied.

Conventionally, as a white phosphor, a ZnS: Pr thin film in which Pr is added as an emission center is known.
Since the emission spectrum was composed of bright lines, a thin-film interference effect appeared, which was dependent on the viewing angle, and had low luminance.
On the other hand, various white phosphors have been realized by a method of adding red components such as Eu and Mn based on a blue-green phosphor of SrS: Ce.

For example, (1) a method using SrS: Ce, Eu in which both Ce and Eu are added as emission centers to a SrS base material,
(2) SrS: Ce / SrS: E using SrS: Ce and SrS: Eu in a multilayer structure
u, (3) SrS: Ce / CaS: Eu using SrS: Ce and CaS: Eu in a multilayer structure, (4) SrS: Ce / ZnS: using SrS: Ce and ZnS: Mn in a multilayer structure. There is a method using Mn.

These SrS: Ce-based white phosphor thin films are:
Although the emission spectrum is broad, it can be said to be an ideal material for white light emission, but the brightness is low, and the obtained white is also a so-called egg-shell white that is close to yellow. Those close to x = 0.3 and y = 0.3 in CIE chromaticity coordinates are not obtained except when a filter is used.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a laminated phosphor and an EL panel which do not require a filter and have good color purity and are particularly suitable for a paper white monocolor EL panel. is there.

[0011]

This and other objects are achieved by any one of the following constitutions (1) to (4). (1) A laminated phosphor having at least a first thin film and a second thin film, wherein a base material of the first thin film contains barium aluminate as a main component, and the base material contains a sulfur element; Further, a laminated phosphor containing Eu as a luminescent center, wherein a base material of the second thin film is mainly zinc sulfide. (2) The laminated phosphor according to the above (1), wherein the mixing amount of the sulfur element and the molar ratio of the oxygen element of the base material, S / (S + O) are 0.02 to 0.5. (3) The composite color of the light emission of the first thin film and the second thin film is x = 0.27 to 0.39 and y = 0.2 in CIE chromaticity coordinates.
The laminated phosphor of the above (1) or (2), which is 7 to 0.38 white. (4) EL having the laminated phosphor of (1) to (3) above
panel.

[0012]

Embodiments of the present invention will be described below in detail. The present invention is a laminate of a phosphor thin film in which a first thin film and a second thin film are laminated, and the obtained laminated phosphor combines the light emission of each layer to emit white light.

[0013] The first thin film of the present invention, as a base material,
The oxide barium aluminate is used.

Conventionally, alkaline earth aluminate thin films have been
There has been no investigation as a thin film phosphor for use. It is presumed that the alkaline earth aluminate was difficult to obtain a crystallized thin film and could not be used as a phosphor thin film that emits EL light. Alkaline earth aluminates are being studied for PDP or fluorescent lamps. A Ba raw material such as barium carbonate, an Al raw material such as alumina, and Eu are added and calcined at 1100 ° C. to 1400 ° C. to synthesize a powder. It is used as a blue phosphor by synthesis.

The inventors thinned barium aluminate as a thin film phosphor for EL. Then, an EL element was formed using this thin film, but no light could be obtained. After annealing at 1100 ° C., EL emission was finally observed. However, at a low luminance of ² cd / m ^2, it was necessary to increase the luminance and reduce the process temperature in order to apply the EL element to a panel.

From these results, in the phosphor thin film of this system, the research was repeated, and it was found that the luminance was drastically improved by adding sulfur to the barium aluminate base material.

The first thin film of the present invention comprises a barium aluminate host material which is an oxide, containing sulfur, and further containing an Eu element as a luminescent center.

The phosphor thin film is preferably one represented by the composition formula Ba _x Al _y O _{z Sw} : Eu. In the above formula, x, y, z and w are elements Ba, Al, O,
Represents the molar ratio of S. x, y, z are preferably x = 1-5 y = 1-15 z = 3-30 w = 3-30.

S / (S + O) in an atomic ratio of sulfur to the barium aluminate base material is 0.01 to 0.95,
In particular, it is preferable to contain it in the range of 0.02 to 0.7. That is, in the above equation, the value of w / (z + w) is 0.0
2 to 0.7, preferably 0.02 to 0.50, especially
It is preferably 0.03 to 0.35.

Sulfur has the effect of dramatically increasing the emission luminance of the phosphor thin film EL. When sulfur is contained in the alkaline earth aluminate, crystallization is promoted at the time of film formation of the base material or at the time of post-treatment such as annealing after the film formation, and the added Eu becomes divalent in the base material, and It is considered that the material has an effective transition in the crystal field and emits light with high luminance.

_{Further, Ba x Al y O z S} w: in Eu, a part of Ba is, Mg, Ca, may be those substituted with Sr, a portion of Al, B, Ga, In, T
It may be replaced by l. With this substitution,
The chromaticity of white is adjustable.

Furthermore, it is preferable to add Eu as a luminescence center. The amount of Eu added is preferably 1 to 10 mol% based on barium atoms. Also,
Other rare earth elements may be added together with Eu, or may be added alone. For example, rare earth elements are Sc, Y, L
a, Ce, Pr, Nd, Gd, Tb, Ho, Er, T
m, Lu, Sm, Eu, Dy, and Yb, but in addition to Eu, Ce, Tb, Ho, Sm, Yb, N
It is preferred to add d. The chromaticity of white can be adjusted by adding these other rare earth elements.

The film thickness is not particularly limited, but if it is too thick, the EL driving voltage increases, and if it is too thin, the luminous efficiency decreases. More specifically, the thickness is about 50 to 1000 nm, particularly about 100 to 400 nm. However, in order to obtain a white phosphor, the thickness ratio to a second thin film described below is important.

The second thin film of the present invention is a thin film whose base material is mainly zinc sulfide. The base material contains ZnS as a main component, and may be a solid solution or a laminate of ZnS and MgS, SrS, BaS, or the like. The emission center includes transition metal elements such as Mn and Cu, rare earth metal elements, P
One or more elements selected from b and Bi can be mentioned. In particular, a ZnS: Mn-based phosphor conventionally used as an orange phosphor thin film is preferable. The second base material has Mn as a luminescent center,
It is preferable that 0.1 to 1.0 mol%, preferably 0.2 to 0.6 mol%, particularly 0.3 to 0.4 mol% is added to the second base material. According to the solid solution with ZnS described above, it is possible to adjust the chromaticity of ZnS: Mn orange,
The chromaticity adjustment of the white of the present invention is possible.

The film thickness is not particularly limited, but if it is too thick, the EL driving voltage increases, and if it is too thin, the luminous efficiency decreases. Specifically, it is about 300 to 2000 nm, particularly about 400 to 800 nm.

The order of lamination and the number of laminations of the first thin film and the second thin film are not particularly limited. A plurality of first thin films and second thin films having the same or different compositions may be used. For example, for the second thin film, ZnS:
A plurality of Mn fluorescent films and a solid solution of ZnMgS: Mn fluorescent film may be used. Using the white color of the present invention, red, green, and blue are extracted by a color filter, and when applied to a display for full color, by a plurality of films described above,
Red, green and blue can be adjusted. These films are preferably formed first under conditions of high film formation temperature.
That is, it is preferable that the thin film having a high film forming temperature is located on the substrate side. Usually, it is preferable to form the second thin film on the first thin film.

By adjusting the ratio T2 / T1 of the total thickness T1 of the first thin film and the total thickness T2 of the second thin film, white (chromaticity) can be adjusted. If the value of T2 / T1 is too large, the color becomes close to yellow, and if it is too small, the color becomes pale white.

In the laminate of the present invention, the combined color of the light emitted from the first thin film and the second thin film is x = 0.27 to CIE chromaticity coordinate.
0.39, y = 0.27-0.38, especially x = 0.30
~ 0.36, y = 0.30 ~ 0.35 high purity white is obtained.

The first thin film is preferably obtained by, for example, the following reactive evaporation method.

For example, binary reactive deposition using Eu-added barium oxide pellets, alumina pellets, and H ₂ S gas. Alternatively, binary vacuum deposition without using Eu-added barium sulfide pellets, alumina pellets, or gas.
Binary reactive vapor deposition using Eu-added barium oxide pellets, alumina pellets, and H ₂ S gas. Barium sulfide pellets, alumina pellets and Eu-added binary vacuum deposition without gas. Binary vacuum deposition without using Eu-added barium oxide pellets, aluminum sulfide pellets, or gas. Binary reactive deposition using Eu-added barium sulfide pellets, aluminum sulfide pellets, and H ₂ S gas. Binary reactive vapor deposition using Eu-added barium sulfide pellets, aluminum sulfide pellets, and O ₂ gas.
Are preferred. After forming the sulfide thin film, the sulfur-added barium aluminate thin film may be obtained by annealing in an oxidizing atmosphere.

Eu to be added is added to the raw material in the form of metal, fluoride, oxide or sulfide. Since the amount of addition differs depending on the raw material and the thin film to be formed, the composition of the raw material is adjusted so as to be an appropriate addition amount.

The substrate temperature during the deposition is 100 ° C. to 600 ° C.
° C, preferably 150 ° C to 300 ° C. If the substrate temperature is too high, the surface of the thin film of the base material becomes very uneven, pinholes are generated in the thin film, and a problem of current leakage occurs in the EL element. For this reason, the above-mentioned temperature range is preferable. Further, it is preferable to perform an annealing treatment after the film formation. The annealing temperature is preferably from 600 ° C to 100 ° C.
0 ° C., especially 800 ° C. to 900 ° C.

The formed oxide fluorescent thin film is preferably a highly crystalline thin film. The evaluation of the crystallinity is, for example, X
It can be performed by line diffraction. In order to increase the crystallinity, the substrate temperature should be as high as possible. Annealing in vacuum, in air, in O ₂ , in N ₂ , in Ar, in S vapor, in H ₂ S, or the like after forming the thin film is also effective.

The pressure during the deposition is preferably 1.33 × 10
^{-4 to} 1.33 × 10 ^-1 Pa (1 × 10 ^-6 to 1 × 10 ^-3
Torr). When introducing a gas such as H ₂ S, the pressure is adjusted to 6.65 × 10 ⁻³ to 6.65 × 10 ⁻² Pa.
(5 × 10 ^{−5 to} 5 × 10 ⁻⁴ Torr). If the pressure is higher than this, the operation of the E-gun becomes unstable,
Composition control becomes extremely difficult. The amount of gas introduced depends on the capacity of the vacuum system, but is 5 to 200 SCCM, especially 1
0-30 SCCM is preferred.

The substrate may be moved or rotated at the time of vapor deposition, if necessary. By moving and rotating the substrate, the film composition becomes uniform, and the variation in the film thickness distribution is reduced.

When the substrate is rotated, the number of rotations of the substrate is preferably 10 times / min or more, more preferably 1 / min.
It is about 0 to 50 times / min, especially about 10 to 30 times / min. If the number of rotations of the substrate is too high, problems such as sealing properties tend to occur when the substrate is introduced into the vacuum chamber. Also,
If it is too slow, composition unevenness occurs in the film thickness direction in the tank, and the characteristics of the produced light emitting layer deteriorate. As a rotating means for rotating the substrate, a power source such as a motor, a hydraulic rotating mechanism, and a power transmission mechanism combining a gear, a belt, a pulley, etc.
It can be constituted by a known rotation mechanism using a reduction mechanism or the like.

The heating means for heating the evaporation source and the substrate only needs to have a predetermined heat capacity, reactivity and the like, and examples thereof include a tantalum wire heater, a sheath heater and a carbon heater. The heating temperature by the heating means is preferably 10
The temperature control accuracy is about ± 1 ° C. at 1000 ° C., preferably about ± 0.5 ° C.

FIG. 1 shows an example of the structure of an apparatus for forming a light emitting layer according to the present invention. Here, a method of producing S-added barium aluminate: Eu while using aluminum sulfide and barium sulfide as evaporation sources and introducing oxygen will be described as an example. In the figure, a substrate 12 on which a light emitting layer is formed and EB evaporation sources 14 and 15 are arranged in a vacuum layer 11.

EB (electron beam) evaporation sources 14 and 15 serving as means for evaporating aluminum sulfide and barium sulfide
Are "crucibles" 40, 5 containing barium sulfide 14a and aluminum sulfide 15a to which luminescent centers are added.
0 and electron guns 41 and 51 containing filaments 41a and 51a for emitting electrons. The electron guns 41 and 51 have a built-in mechanism for controlling a beam.
AC power supplies 42 and 52 and bias power supplies 43 and 53 are connected to the electron guns 41 and 51, respectively. The electron beam is controlled by the electron gun, and the barium sulfide and the aluminum sulfide to which the luminescent center is added can be alternately evaporated at a predetermined ratio with a preset power. An evaporation method for performing simultaneous multiple evaporation with one E gun is called a multiple pulse evaporation method. In this example, an EB evaporation source was used as an evaporation source for aluminum sulfide and barium sulfide, but one or both of them may be replaced with another evaporation source such as a resistance heating evaporation source.

The vacuum chamber 11 has an exhaust port 11a,
By exhausting from the exhaust port, the inside of the vacuum chamber 11 can be set to a predetermined degree of vacuum. The vacuum chamber 11 has a source gas introduction port 11b for introducing a hydrogen sulfide gas or the like.

The substrate 12 is fixed to a substrate holder 12a, and a fixed shaft 12b of the substrate holder 12a is rotatably fixed from the outside while maintaining the degree of vacuum in the vacuum chamber 11 by rotating shaft fixing means (not shown). I have. And
Rotation means (not shown) can rotate at a predetermined rotation number as needed. Also, the substrate holder 1
2a is a heating means 1 composed of a heater wire or the like.
3 is closely attached and fixed, and heats the substrate to a desired temperature;
It can be held.

Using such an apparatus, the EB evaporation source 14,
Barium sulfide vapor and aluminum sulfide vapor evaporated from 15 are combined with the oxygen introduced and deposited on the substrate 12 to form an S-doped oxide fluorescent layer. At that time, by rotating the substrate 12 as necessary, the composition and the film thickness distribution of the light emitting layer to be deposited can be made more uniform.

The second thin film can be formed by a known method such as an evaporation method using ZnS: Mn pellets and a sputtering method using a ZnS target.

As described above, according to the fluorescent thin film material and the manufacturing method by vapor deposition of the present invention, a phosphor thin film having a laminated structure that emits white light with high luminance can be easily formed.

In order to obtain an inorganic EL device using the light emitting layer 3 of the present invention, for example, a structure as shown in FIG. 2 may be used. Substrate 1, electrodes 5, 6, thick insulating layer 2, thin insulating layer 4
Between them, an intermediate layer such as a layer for increasing adhesion, a layer for relaxing stress, a layer for preventing a reaction, and the like may be provided. The surface of the thick film may be polished or a flattening layer may be used to improve the flatness.

FIG. 2 shows inorganic E using the laminated phosphor of the present invention.
FIG. 3 is a partial cross-sectional perspective view showing a structure of an L element. In FIG. 2, a lower electrode 5 having a predetermined pattern is formed on a substrate 1, and a first insulating layer (thick dielectric layer) 2 of a thick film is formed on the lower electrode 5. Further, on the first insulating layer 2, a light emitting layer 3, a second insulating layer (thin film dielectric layer)
4 are sequentially formed, and an upper electrode 6 is formed on the second insulating layer 4 in a predetermined pattern so as to form a matrix circuit with the lower electrode 5. The light emitting layer uses the laminated phosphor.

The material used for the substrate is a thick film forming temperature,
And EL phosphor layer formation temperature, EL element annealing temperature
Heat resistant temperature or melting point that can withstand 600 ° C or more, preferably
Use a substrate at 700 ° C or higher, especially 800 ° C or higher.
EL device by a functional thin film such as a light emitting layer formed on
Can be formed and can maintain a predetermined strength.
It is not limited. Specifically, glass or
Alumina (Al_TwoO_Three), Forsterite (2MgO
SiO_Two ), Steatite (MgO.SiO) _Two ),village
Site (3Al_TwoO_Three ・ 2SiO_Two ), Berylia (Be
O), aluminum nitride (AlN), silicon nitride (S
iN), ceramics such as silicon carbide (SiC + BeO)
Heat-resistant glass substrates such as glass substrates and crystallized glass
Can be. Of these, the heat resistant temperature is about 1000 ° C or less
The above is preferred. Of these, alumina-based
Plate, crystallized glass is preferred, and when thermal conductivity is required
Is preferably beryllia, aluminum nitride, silicon carbide, etc.
New

In addition, a metal substrate made of titanium, stainless steel, inconel, iron, or the like, such as quartz or thermally oxidized silicon wafer, can be used. When a conductive substrate such as a metal substrate is used, a structure in which a thick film having electrodes inside is formed on the substrate is preferable.

As the dielectric thick film material (first insulating layer), a known dielectric thick film material can be used. Further, a material having a relatively large dielectric constant is preferable.

For example, materials such as lead titanate, lead niobate, and barium titanate can be used.

The resistivity of the dielectric thick film is 10 ⁸ Ω ·
cm or more, particularly about 10 ¹⁰ to 10 ¹⁸ Ω · cm. It is also preferable that the material has a relatively high dielectric constant,
The dielectric constant ε is preferably ε = 100 to 100
It is about 00. The film thickness is preferably from 5 to 50 μm, particularly preferably from 10 to 30 μm.

The method for forming the insulating layer thick film is not particularly limited, and a method in which a film having a thickness of 10 to 50 μm can be obtained relatively easily is preferable.

In the case of the printing and baking method, the particle size of the material is appropriately adjusted and mixed with a binder to obtain a paste having an appropriate viscosity. This paste is formed on a substrate by a screen printing method and dried. The green sheet is fired at an appropriate temperature to obtain a thick film.

As a constituent material of the thin film insulating layer (second insulating layer), for example, silicon oxide (SiO ₂ ), silicon nitride (SiN), tantalum oxide (Ta ₂ O ₅ ), strontium titanate (SrTiO ₃ ), Yttrium oxide (Y ₂ O ₃ ), barium titanate (BaTiO ₃ ), lead titanate (PbTiO ₃ ), PZT, zirconia (Zr
O _2), silicon oxynitride (SiON), alumina (Al ₂ O _3), lead niobate, PMN-PT based material and can be exemplified these multilayer or mixed thin film, the insulating layer with these materials As a method of forming,
Existing methods such as an evaporation method, a sputtering method, a CVD method, a sol-gel method, and a printing and baking method may be used. In this case, the thickness of the insulating layer is preferably 50 to 1000 nm, especially 10 to 1000 nm.
It is about 0 to 500 nm.

The electrode (lower electrode) is formed at least on the substrate side or in the first dielectric. When forming a thick film, the electrode layer exposed to the high temperature of the heat treatment together with the light emitting layer further includes palladium, rhodium, iridium, rhenium, ruthenium, platinum, tantalum, nickel, chromium, as a main component.
One or more commonly used metal electrodes such as titanium may be used.

The other electrode layer serving as the upper electrode has
Normally, the light emission is taken out from the opposite side of the substrate,
A transparent electrode having a light-transmitting property in a wavelength range is preferable. Transparent
The pole takes out the emitted light from the substrate side if the substrate is transparent
It may be used for the lower electrode because it can be used. This place
In particular, it is particularly preferable to use a transparent electrode such as ZnO or ITO.
preferable. ITO is usually In_TwoO_Three Chemistry with SnO
Although it is contained in a stoichiometric composition, the O content is slightly deviated from this
You may. In_TwoO_Three SnO against_Two Is 1
-20% by mass, more preferably 5-12% by mass. Ma
Also, In at IZO _TwoO_Three The mixing ratio of ZnO to
Usually, it is about 12 to 32% by mass.

Further, the electrode may have silicon. This silicon electrode layer is made of polycrystalline silicon (p-S
i) or amorphous (a-Si), and if necessary, single crystal silicon.

The electrodes are doped with impurities in order to ensure conductivity in addition to silicon as the main component. The dopant used as the impurity only needs to be able to secure predetermined conductivity, and a normal dopant used for a silicon semiconductor can be used. Specifically, B,
Examples thereof include P, As, Sb, and Al. Among them, B, P, As, Sb, and Al are particularly preferable. The concentration of the dopant is preferably about 0.001 to 5 at%.

As a method for forming an electrode layer using these materials, existing methods such as a vapor deposition method, a sputtering method, a CVD method, a sol-gel method, and a printing and firing method may be used. In particular, an electrode is formed inside a substrate. When fabricating a structure having a thick film having the same, the same method as that for forming a dielectric thick film is preferable.

The preferable resistivity of the electrode layer is 1 Ω · cm or less, particularly 0.003 to 0.1 Ω · cm, in order to efficiently apply an electric field to the light emitting layer. The thickness of the electrode layer depends on the material to be formed, but is preferably from 50 to 200.
0 nm, especially about 100 to 1000 nm.

The case where the light emitting layer of the present invention is applied to an inorganic EL device has been described above. However, any device that can use the phosphor thin film of the present invention can be used in other forms, such as a device that emits white light. If it is used, it can be applied to a monocolor panel for a display.

[0062]

EXAMPLES Hereinafter, the present invention will be described in more detail by showing specific examples of the present invention.

Embodiment 1 FIG. 1 shows an example of a vapor deposition apparatus that can be used in the manufacturing method of the present invention. Here, 2
One E gun and one resistance heating cell were used in place of the point control gun.

The EB source 15 containing the BaS powder to which 5 mol% of Eu was added, and the resistance heating cell source (1 containing the Al ₂ S ₃ powder)
4) is provided in the vacuum chamber 11, and is evaporated from the respective sources at the same time, heated to 400 ° C., and Ba _{x is} placed on the rotated substrate.
Al _y O _z S _w: was formed Eu layer. The evaporation rate of each evaporation source was adjusted so that the obtained thin film was 1 nm / sec. At this time, ₂₀ SCCM of H ₂ S gas was introduced. After forming the thin film, the film was annealed for 10 minutes in an air atmosphere at 750 ° C. to form a first thin film having a thickness of 300 nm.

On this, Zn added with 0.5 mol% of Mn was added.
Using an S pellet, a second thin film having a thickness of 4 was formed by EB evaporation.
00 nm was formed.

A first thin film Ba _x Al _y O _z S _w : Eu thin film was separately prepared and analyzed for composition by fluorescent X-ray analysis.
Ba: Al: O: S: Eu = 7.40: 19 in atomic ratio.
18: 70.15: 2.90: 0.36.

Further, an EL device using the light emitting layer was manufactured. By applying an electric field of 1 kHz and a pulse width of 50 μS to the electrode, a white light emission luminance of 500 cd / m ² was obtained with good reproducibility. The emission color is x = 0.35 in CIE chromaticity coordinates
2. Paper white was obtained at y = 0.303.

As described above, the laminated phosphor of the present invention makes it possible to obtain a white phosphor thin film material which emits light with high color purity and high luminance without using a filter.

Also, an EL using such a laminated phosphor is described.
The element has excellent light-emitting characteristics, and can particularly form a white EL element and a monochrome EL panel, and has great practical value.

[0070]

As described above, according to the present invention, there is no need for a filter, good color purity, and especially white and black E
A laminated phosphor and an EL panel suitable for L can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing an apparatus to which a method of the present invention can be applied or a configuration example of a manufacturing apparatus of the present invention.

FIG. 2 is an inorganic EL that can be manufactured by the method and apparatus of the present invention.
FIG. 3 is a partial cross-sectional view illustrating a configuration example of an element.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 substrate 2 first insulating layer (dielectric layer) 3 phosphor thin film (light emitting layer) 4 second insulating layer (dielectric layer) 5 lower electrode 6 upper electrode (transparent electrode) 11 vacuum chamber 12 substrate 13 heating means 14 EB evaporation source 15 EB evaporation source

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 33/14 H05B 33/14 Z F term (Reference) 3K007 AB02 AB04 CA01 CB01 DA05 FA01 4H001 CA02 CA05 CA06 XA08 XA13 XA16 XA30 XA56 YA63

Claims (4)

[Claims] 1. A laminated phosphor having at least a first thin film and a second thin film, wherein a base material of the first thin film contains barium aluminate as a main component, and the base material contains a sulfur element. And a base phosphor of the second thin film, wherein the base material of the second thin film is mainly zinc sulfide. 2. The mixture ratio of the sulfur element and the molar ratio of the oxygen element of the base material, S / (S + O) is 0.02 to 0.5.
The laminated phosphor according to claim 1, which is: 3. The composite color of light emitted from the first thin film and the second thin film is x = 0.27 to 0.39, y = 2 in CIE chromaticity coordinates.
3. The laminated phosphor according to claim 1, wherein the phosphor is 0.27 to 0.38 white. 4. An EL comprising the laminated phosphor according to claim 1.
panel.