JP2001143872A - Complex substrate and electroluminescent element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a complex substrate which can be sintered in a range of temperature at which a ceramic substrate is not reacted on firing and can form a electroluminescent element having a sufficient luminescence property, and the luminescent element using the same. SOLUTION: The complex substrate has an electric insulating substrate 4, an electrode layer 6 formed on the substrate 4 and a dielectric layer 8 formed on the electrode layer 6 and composed of a barium titanate ceramic sintered compact fired at a temperature of 1000 deg.C to 3000 deg.C. The dielectric layer 8 contains preferably 0.1-20 mol of lithium silicate in terms of Li2SiO3, per 100 mol of barium titanate in terms of BaTiO3. El element is obtainable by forming a luminous layer 12 on the dielectric layer 8 of the complex substrate and forming a transparent electrode 16 on the luminous layer 12, if required, by inserting an insulating layer 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite substrate having a dielectric layer and an electrode layer, and an electroluminescent device using the composite substrate.

[0002]

2. Description of the Related Art A phenomenon in which a substance emits light by application of an electric field is called electroluminescence (EL), and an element using this phenomenon has been put to practical use as a backlight of a liquid crystal display (LCD) or a watch. The electroluminescent element was formed by dispersing a powdered fluorescent substance into an organic substance or an enamel, and having a structure in which electrodes were provided on the upper and lower sides and a form in which an electrode was sandwiched between two electrodes on an electrically insulating substrate. There is a thin film type device using a thin film phosphor. In addition, there are a DC voltage driving type and an AC voltage driving type depending on the driving method.

[0003] Dispersion type electroluminescent elements have been known for a long time and have the advantage of being easy to manufacture, but their use is limited because of their low luminance and short life. On the other hand, the thin film type electroluminescent device has characteristics of high luminance and long life, and has greatly expanded the practical range of the electroluminescent device.

Conventionally, in a thin film type electroluminescent device, a method of using glass as a substrate, forming a transparent electrode layer of ITO or the like in contact with the substrate, and taking out light emitted from the phosphor layer from the substrate side has been the mainstream. (For example, JP-B-62-40836). However, in recent years, development of devices using an electrically insulating ceramic substrate as a substrate and using a thick dielectric layer instead of a thin insulating layer has been reported.

[0005] The basic structure of this device is different from the conventional structure, and the transparent electrode layer is provided on the upper part in order to take out the light emission of the phosphor from the upper part opposite to the substrate. As a feature of this element, since the thick film dielectric is used as the insulating layer, it is resistant to dielectric breakdown, and high reliability and high production yield can be obtained. In addition, when a normal glass substrate was used, the heat treatment of the fluorescent layer had to be performed at a temperature of about 600 ° C. or less at most.
By using a ceramic substrate and a thick dielectric layer, the heat treatment temperature can be increased. As a result, crystal defects in the light emitting layer can be reduced, and high light emitting characteristics can be obtained.

In the past, many electroluminescent devices using a thick-film dielectric developed using a material containing lead as the dielectric (for example, Japanese Patent Publication No. 7-440).
No. 72, JP-A-7-50197). this is,
The reason is that the dielectric material containing lead has a low firing temperature of usually 1000 ° C. or lower, and can be fired without reacting with a substrate that causes characteristic deterioration. However, since the phosphor layer also needs to be heat-treated at a temperature lower than that temperature, it has been difficult to produce an element having sufficient light emitting characteristics. In addition, lead is a problem due to its toxicity, and its use is currently being restricted.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a composite substrate which can be sintered in a temperature range which does not react with the substrate at the time of sintering and which can produce an electroluminescent device having sufficiently high luminescence characteristics. A light-emitting element using the same is provided.

[0008]

In order to achieve the above object, a composite substrate according to the present invention comprises an electrically insulating substrate, an electrode layer formed on the substrate, and an electrode layer formed on the electrode layer. And a dielectric layer composed of a ceramic sintered body containing barium titanate as a main component and fired at a temperature of more than 1000 ° C. and less than 1300 ° C.

[0009] In the present invention, the barium titanate is represented by a composition formula _{Ba m TiO 2 +} m, m in the composition formula is 0.9 ≦ m ≦ 1.1, the ratio of Ba and Ti 0. It is preferable that 95 ≦ Ba / Ti ≦ 1.05.

It is preferable that the dielectric layer contains an alkali component. The alkali component is not particularly limited, but is preferably at least one of lithium oxide, potassium oxide, and sodium oxide. Instead of the alkali component, one of silicon oxide, bismuth oxide, boron oxide and aluminum oxide is used.
It may contain at least species or more.

Particularly preferably, when the barium titanate is converted to BaTiO ₃ to make 100 mol, lithium silicate is converted to Li ₂ SiO _3, and is preferably 0.1 to 0.1 mol.
A content of 20 mol is contained in the dielectric layer. The dielectric layer may contain one or more of manganese oxide, magnesium oxide, yttrium oxide, vanadium oxide, tungsten oxide, silicon oxide, calcium oxide, zirconium oxide, niobium oxide, and cobalt oxide. .

In order to achieve the above object, an electroluminescent device according to the present invention comprises: the composite substrate; a light emitting layer formed on a dielectric layer of the composite substrate; And a transparent electrode layer formed on the substrate. An insulating layer may be interposed between the light emitting layer and the transparent electrode layer.

[0013]

[Operation and Effect] Barium titanate (hereinafter simply referred to as Ba)
TiO ₃ ) is generally well known as a high dielectric constant material, and is widely used as a capacitor material because of its high dielectric constant, high withstand voltage, and low cost.

However, BaTiO ₃ is generally 130
A high firing temperature of 0 ° C. or higher is required. Therefore, when a conventional BaTiO ₃ -based material is formed into a thick film on a ceramic substrate and baked, the dielectric layer reacts with the substrate, and the electrical characteristics of the dielectric layer deteriorate.

In the present invention, since the sintering temperature of the BaTiO ₃ dielectric is low, there is no reaction with the ceramic substrate, and a composite substrate with a dielectric having a high dielectric constant, insulation resistance, withstand voltage and high reliability is obtained. Can be made.

In the present invention, by using a dielectric having the above composition, a composite substrate which can be fired at a temperature lower than 1300 ° C. can be produced. In the electroluminescence device using the composite substrate, it is possible to reduce the light emission starting voltage and to improve the light emission luminance under the same applied voltage.

[0017] The composite substrate of the present invention comprises a luminescent layer,
By forming a functional film such as an insulating layer and another electrode layer, a thin film / thick film hybrid EL device can be obtained. In particular, since the composite substrate of the present invention is a sintered material, it is necessary to form a thin film or a heat treatment after forming a luminescent layer which is a functional film.
Also suitable for thick-film hybrid EL devices.

To obtain a thin-film / thick-film hybrid EL device using the composite substrate of the present invention, a light-emitting layer / another insulating layer (dielectric layer) / another electrode layer is formed on a dielectric layer in this order. do it.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments shown in the drawings. FIG. 1 is a sectional view of a main part of an electroluminescent element according to the present invention. Electroluminescent element (EL element) 2 according to the embodiment of the present invention
Has a composite substrate 10. The composite substrate 10 includes an electrically insulating substrate 4 and an internal electrode layer 6 formed on the substrate 4.
Formed on the internal electrode layer 6,
And a dielectric layer 8 composed of a ceramic sintered body containing barium titanate as a main component and fired at a temperature lower than 0 ° C. A light emitting layer 12 is formed on the dielectric layer 8 of the composite substrate 10, and a transparent electrode layer 16 is formed on the light emitting layer 12 via an insulating layer 14. Note that the insulating layer 14 may be omitted.

Substrate 4 The substrate 4 is not particularly limited as long as it has electrical insulation properties and can maintain a predetermined strength without contaminating the internal electrode layer 6 and the dielectric layer 8 formed thereon. Not something. As a specific material, alumina (Al ₂ O
₃ ), forsterite (2MgO.SiO ₂ ),
Steatite (MgO.SiO ₂ ), Mullite (3A
_{l 2 O 3 · 2SiO 2)} , beryllia (BeO),
Aluminum nitride (AlN), silicon nitride (Si
N) and a ceramic substrate such as silicon carbide (SiC + BeO). Further, crystallized glass having heat resistance can be used as the substrate 4. The thickness of the substrate is usually about 0.1 to 10 mm, preferably about 0.5 to 5 mm, and more preferably about 1 to 3 mm.

Internal Electrode Layer 6 The internal electrode layer 6 is not particularly limited. For example, Mn, Fe, Co, Ni, Cu, Si, W, Mo, Pb
, One or more base metals, Ni-Cu, Ni-
Base metal alloys such as Mn, Ni-Cr, Ni-Co, Ni-Al, or Ag, Au, Pt, Rh, Ru,
It is composed of one or more noble metals of Ir and Pd, or a noble metal alloy such as Ag-Pd and Au-Ag. The electrode layer may contain glass frit. Adhesion with the substrate 4 serving as a base can be improved.

When the paste for the electrode layer is prepared, it may have an organic binder. The organic binder is the same as the above-mentioned substrate. Further, additives such as various dispersants, plasticizers, and insulators may be contained in the electrode layer paste as needed. Their total content is
It is preferably 1% by mass or less.

The thickness of the internal electrode layer 6 is usually set to 0.1.
It is about 5-5 μm, preferably about 1-3 μm. The internal electrode layer 6 is formed on the surface of the substrate 4, for example, in a stripe pattern at a predetermined interval by a thick film method such as a screen printing method.

Dielectric layer 8 The dielectric layer 8 is composed of a high dielectric constant ceramic sintered body containing BaTiO ₃ as a main component, and contains lithium oxide, potassium oxide, sodium oxide and the like in the sintered body. Alkali component, or silicon oxide, bismuth oxide,
First containing at least one kind of boron oxide or aluminum oxide
Secondary components have been added. As the first subcomponent, lithium silicate (Li ₂ SiO ₃ ) is particularly preferably used. By adding such an additive, the dielectric layer 8 can be fired at a temperature lower than 1300 ° C.

BaTiO₃Is 100 moles
The amount of the first sub-component in the dielectric layer 8 is
To Li₂O, K₂O, Na₂O, SiO₂, B
₂O ₃Or Al₂O₃Converted to
Is 0.01 to 20 mol, more preferably 0.1 to 10 mol.
Mol, particularly preferably 0.5 to 5 mol. 1st by-product
If the amount added is too small, the firing temperature tends to increase.
Yes, too much tends to lower the dielectric constant
You.

In the dielectric layer 8, manganese oxide,
A second subcomponent containing at least one of magnesium oxide, yttrium oxide, vanadium oxide, tungsten oxide, silicon oxide, calcium oxide, zirconium oxide, niobium oxide, and cobalt oxide may be included.
As the second subcomponent, MgO, MnO or (Ba, C
a) SiO _{3 and the} like are particularly preferred.

The content of the second subcomponent when the BaTiO ₃ as 100 mol, MnO a second subcomponent, Mg
O, Y ₂ O ₃ , V ₂ O ₅ , WO ₃ , SiO
₂ , CaO, ZrO ₂ , Nb ₂ O ₅ or Co
Preferably 0.05 to 5 mol in terms of ₂ O ₃ ,
More preferably, 0.1 to 3 mol, particularly preferably 0.1 to 3 mol.
5 to 2 mol. If the added amount of the second subcomponent is too small, the reliability tends to decrease, and if it is too large, the dielectric constant tends to decrease.

The following are particularly preferred dielectric materials:
Is included. As a main component of the dielectric layer 8,
Lithium silicate and lithium oxide
Gnesium, manganese oxide, yttrium oxide,
Vanadium oxide, barium oxide, and calcium oxide
And silicon oxide. Barium titanate to Ba
TiO₃Lithium silicate into Li₂SiO₃To
Magnesium oxide to MgO, manganese oxide to MnO
And yttrium oxide to Y₂O₃And vanadium oxide
V₂O₅And barium oxide to BaO
Lucium to CaO, silicon oxide to SiO₂Each
When converted, the ratio of each compound in the dielectric layer
Is BaTiO₃Li per 100 moles₂SiO
₃: 0.1 to 20 mol, preferably 1 to 10 mol, M
gO: 0.1-3 mol, preferably 1-3 mol, Mn
O: 0.05 to 1.0 mol, preferably 0.1 to 0.3
Mole, Y₂ O₃: 0.1 to 3 mol, preferably 1 to 3
Mole, V₂O₅: 0.01 to 1 mol, preferably
0.05 to 0.15 mol, BaO + CaO: 2 to 12 mol
, SiO₂: 2 to 12 mol.

The ratio of (BaO + CaO) / SiO ₂ is not particularly limited, but is usually preferably from 0.9 to 1.1. BaO, CaO and SiO ₂ are (Ba)
_x Ca _1-x O) _y · SiO ₂ may be included. In this case, it is preferable that 0.3 ≦ x ≦ 0.7 and 0.95 ≦ y ≦ 1.05 in order to obtain a dense sintered body. (Ba _x Ca _1-x O) _y · Si
The content of O ₂ is preferably 1 to 10% by mass, more preferably 4 to 6% by mass, based on the total mass of the dielectric layer 8. The oxidation state of each oxide is not particularly limited as long as the content of the metal element constituting each oxide is within the above range.

The reasons for limiting the contents of the respective subcomponents are as follows. By setting the content of lithium silicate within the above range, a dielectric layer having good dielectric properties can be fired without reacting with the substrate at a temperature higher than 1000 ° C. and lower than 1300 ° C.

By setting the content of magnesium oxide in the above range, the temperature characteristics of the capacitance in the dielectric layer can be set in a desired range, and the change with time of the capacitance can be suppressed. As a result, it is possible to suppress a change in temperature and a change with time in light emission luminance in the electroluminescence element. By setting the content of manganese oxide in the above range, the reliability of the insulation resistance can be improved and the breakdown voltage can be increased. This allows
The stability and reliability of the electroluminescent element are improved. By setting the content of yttrium oxide in the above range, it is possible to suppress a change with time in the capacitance and the insulation resistance of the dielectric layer. For this reason, the reliability of the electroluminescence element and the stability of the emission luminance are improved. By setting the content of vanadium oxide in the above range, the temperature characteristics of the capacitance can be set in a desired range, and the breakdown voltage can be increased. For this reason, the temperature stability of the emission luminance of the electroluminescent element is improved, and at the same time, the reliability can be improved.
Further, BaO + CaO, SiO ₂ , (Ba _x Ca
_By setting the content of _1-xO ) _y · SiO _{2 in} the above range, the temperature characteristics of the capacitance of the dielectric layer can be set in a desired range and contribute to improvement of sinterability. . Thereby, the temperature stability of the emission luminance of the electroluminescence element is improved.

The dielectric layer 8 is formed by printing a dielectric paste made from a powdery dielectric material as a raw material by a thick film method such as a screen printing method, like the internal electrode layer 6. Alternatively, a green sheet is formed by casting a dielectric paste,
This may be laminated and pressed on the internal electrode 6. Moreover,
The internal electrode layer 6 may be printed on a dielectric green sheet (dielectric layer 8), and may be pressed on the substrate 4.

The dielectric layer 8 is fired simultaneously with the internal electrode layer 6 on the substrate 4. The firing temperature is higher than 1000 ° C and lower than 1300 ° C, preferably higher than 1000 ° C and 1250 ° C or lower, more preferably 1100 ° C or higher and 1200 ° C or lower. The thickness of the dielectric layer 8 is 2 to 2 due to manufacturing problems.
3 μm or more is required. If the dielectric layer 8 is too thick, not only does the capacitance decrease and the voltage applied to the light emitting layer 12 decreases, but also the spread of the internal electric field causes an image to bleed or crosstalk when the display element is used. Can occur. Therefore, the thickness of the dielectric layer 8 is preferably 300 μm or less, and more preferably 5 to 100 μm.

[0034] As the material of the light-emitting layer 12 light-emitting layer 12, for example, a material such as those described in Monthly Display '98 April recent display of technological trends (Tanaka Ministry work copyright) p1~10 Can be mentioned. Specifically, as a material for obtaining red light emission, such as ZnS, Mn / CdSSe, or a material for obtaining green light emission, such as ZnS: TbOF, ZnS: Tb, Zn
S: As a material for obtaining blue light emission such as Tb, Sr
S: Ce, (SrS: Ce / ZnS) n, CaCa ₂
S ₄ : Ce, Sr ₂ Ga ₂ S ₅ : Ce and the like can be mentioned. Further, Sr is used to obtain white light emission.
S: Ce / ZnS: Mn and the like are known.

Of these, IDW (Intern)
nationalDisplayWorkshop) '
97 X. Wu "Multicolor Thin-
Film Ceramic Hybrid-EL Di
Particularly preferable results can be obtained by applying the composite substrate of the present invention to an EL element having a blue light-emitting layer of SrS: Ce, which has been studied in “sprays” p593to596.

The thickness of the light emitting layer is not particularly limited, but if it is too thick, the driving voltage increases, and if it is too thin, the luminous efficiency decreases. Specifically, although it depends on the fluorescent material, it is preferably 100 to 1000 nm, especially 150 to 1000 nm.
It is about 500 nm.

The light emitting layer 12 can be formed by a thin film method such as a vapor deposition method. Examples of the vapor deposition method include physical vapor deposition methods such as a sputtering method and a vapor deposition method, and CV
Chemical vapor deposition such as Method D can be used.

Further, as described in the above-mentioned IDW, when a luminous layer of SrS: Ce is formed, H
_When formed by an electron beam evaporation method in a 2S atmosphere, a high-purity light-emitting layer can be obtained.

After the formation of the light emitting layer, a heat treatment is preferably performed. The heat treatment may be performed after the electrode layer, the dielectric layer, and the luminescent layer are stacked from the substrate side, or the electrode layer, the insulating layer, the luminescent layer, the insulating layer, or the transparent electrode layer may be formed on the electrode layer from the substrate side. After formation, cap annealing may be performed. Usually, it is preferable to use the cap annealing method. The temperature of the heat treatment is preferably from 600 to the sintering temperature of the substrate, more preferably from 600 to 1300 ° C, especially from 600 to 1200 ° C.
℃, treatment time is 10-600 minutes, especially 30-180
Minutes. The atmosphere during the annealing process is N
An atmosphere in which O ₂ is 0.1% or less in ₂ , Ar, He, or N ₂ is preferable.

The insulating layer formed on the light emitting layer 12 has a resistivity of 10 ⁸ Ω · cm or more, particularly 10 ¹⁰ to 10 ¹⁸ Ω.
-About cm is preferable. Further, it is preferable that the substance has a relatively high dielectric constant, and the relative dielectric constant ε thereof is preferably about 3 to 1000.

As a constituent material of the insulating layer, for example, acid
Silicon (SiO)₂), Silicon nitride (Si₃N
₄), Tantalum oxide (Ta)₂O₅), Titanium titanate
Trontium (SrTiO₃), Yttrium oxide
(Y₂O₃), Barium titanate (BaTi
O₃), Lead titanate (PbTiO)₃), Zirconia
(Zr ₂O₃), Silicon oxynitride (S
iON), alumina (Al₂O₃), Lead niobate (P
bNbO₃) And the like.

The method for forming the insulating layer 14 from these materials is the same as that for the light emitting layer 12 described above. In this case, the thickness of the insulating layer 14 is preferably 50 to 1000
nm, especially about 100 to 500 nm.

Transparent Electrode Layer 16 The transparent electrode layer 16 is not particularly limited.
(Indium oxide doped with tin as a different additive) film; SnO ₂ film; Sn doped with Sb and F
O ₂ film; ZnO doped with Al, In, B and F
And the like. In addition, the transparent electrode layer 16 does not necessarily need to be completely transparent, and may be translucent. From such a viewpoint, the transparent electrode layer 1
6 may be an electrode layer in which the light transmittance is increased by adjusting the thickness of the metal film.

The pattern of the transparent electrode layer 16 is not particularly limited, but may be, for example, a stripe in a direction substantially perpendicular to the stripe-shaped internal electrode layer 6. Striped transparent electrode layer 16 and striped internal electrode layer 6
When the luminous body layer 12 corresponding to the intersection with is selectively emitted, light is displayed as viewed from the transparent electrode side. The pattern processing of the transparent electrode layer 16 can be performed by, for example, photolithography.

Other Configurations In the above example, the case where only a single light emitting layer is used has been described. However, the thin film EL device of the present invention is not limited to such a configuration, A plurality of light-emitting layers may be stacked, or different types of light-emitting layers (pixels) may be combined in a matrix and arranged in a plane.

In the thin-film EL device of the present invention, by using a composite substrate material obtained by firing, a light-emitting layer capable of emitting high-luminance blue light can be easily obtained. High performance, due to the smooth surface of the layer
A high-definition color display can also be formed.
Further, the manufacturing process is relatively easy, and the manufacturing cost can be kept low. Since efficient and high-luminance blue light emission can be obtained, the light-emitting element may be combined with a color filter in order to form a white light-emitting element.

As the color filter film, a color filter used in a liquid crystal display or the like may be used, but the characteristics of the color filter are adjusted according to the light emitted from the EL element to optimize the extraction efficiency and color purity. do it.

If a color filter capable of cutting off short-wavelength external light that is absorbed by the EL element material or the fluorescence conversion layer is used, the light resistance of the element and the display contrast are improved. Further, an optical thin film such as a dielectric multilayer film may be used instead of the color filter.

The fluorescence conversion filter film absorbs EL light and emits light from the phosphor in the fluorescence conversion film to convert the color of the emitted light. It is formed from a fluorescent material and a light absorbing material.

As the fluorescent material, basically, a material having a high fluorescence quantum yield may be used, and it is desirable that the material has strong absorption in an EL emission wavelength region. In practice, laser dyes and the like are suitable, and rhodamine compounds, perylene compounds, cyanine compounds, phthalocyanine compounds (including subphthalocyanines, etc.) naphthalimide compounds, condensed ring hydrocarbon compounds, condensed heterocyclic compounds A styryl compound, a coumarin compound or the like may be used.

As the binder, a material that does not quench the fluorescence may be basically selected, and a binder that can be finely patterned by photolithography, printing, or the like is preferable. Further, when formed on the substrate in contact with the transparent electrode, a material that does not damage the transparent electrode layer (ITO) is preferable.

The light absorbing material is used when the light absorption of the fluorescent material is insufficient, but may be omitted when unnecessary. As the light absorbing material, a material that does not quench the fluorescence of the fluorescent material may be selected. The thin film EL device of the present invention
Usually, pulse driving or AC driving is performed, and the applied voltage is about 50 to 200 V.

In the above example, a thin-film EL device is described as an application example of the composite substrate. However, the composite substrate of the present invention is not limited to such applications, but can be applied to various electronic materials and the like. It is. For example, application to a thin film / thick film hybrid high frequency coil element or the like is possible.

The method of manufacturing a composite substrate 10 first, the surface of the substrate 4, printed by the thick film method, and the conductive paste for forming the internal electrode layer 6, a dielectric paste for forming a dielectric layer 8 I do. After that, binder removal processing and firing processing are performed.

The conditions for the binder removal treatment performed before firing may be ordinary conditions, but it is particularly preferable to perform the following conditions. Heating rate: 5 to 300 ° C / hour, especially 10 to 100 ° C / hour
Time, holding temperature: 200 to 700 ° C, especially 300 to 600 ° C, Temperature holding time: 0.5 to 24 hours, especially 5 to 20 hours, Atmosphere: in air.

The atmosphere at the time of firing may be appropriately determined according to the type of the conductive material in the electrode layer paste. The holding temperature at the time of firing is more than 1000 ° C and less than 1300 ° C,
It is preferable that the temperature be set to ~ 1200 ° C. If the holding temperature is lower than the above range, densification is insufficient, and if it exceeds the above range, the substrate reacts with the dielectric. The firing atmosphere is
This is possible even in a reducing atmosphere. The temperature holding time during firing is preferably 0.5 to 8 hours, particularly preferably 1 to 3 hours. As described above, the composite substrate 10 shown in FIG. 1 can be obtained.

[0057]

EXAMPLES Hereinafter, the present invention will be described based on more detailed examples, but the present invention is not limited to these examples. Example 1 An alumina substrate 4 having a purity of 99.5% was prepared. The thickness of the substrate 4 was 1.1 mm. On this substrate 4, a Pd paste was applied with a width of 1.5 mm and a gap of 1.5 m.
screen printing with a stripe pattern of m
Drying was performed at 10 ° C. for several minutes.

Separately, BaTiO ₃ powder was mixed with a binder composed of ethyl cellulose and α-terpineol to prepare a dielectric paste. The prepared dielectric paste was printed on the substrate on which the above-mentioned electrode pattern was printed so as to have a thickness of 20 μm, dried, and then baked at 1250 ° C. for 2 hours to obtain a composite substrate 10.
Was prepared. The thickness of the dielectric layer 8 after firing was 12 μm.

Next, a light emitting layer 12 was formed on the surface of the dielectric layer 8 of the composite substrate 10. The luminous body layer 12 is formed by heating the composite substrate to 600 to 700 ° C., and then forming an SrS thin film doped with Ce so that the thickness becomes 0.7 μm.
It was formed by an electron beam evaporation method in an atmosphere.
Then, on the surface of the luminous body layer 12,
An i ₃ N ₄ thin film was formed by sputtering to a thickness of 0.2
μm, and then as a transparent electrode 16, I
A TO thin film was formed with a thickness of 0.3 μm by a sputtering method in an Ar + O ₂ atmosphere to obtain an EL element. Table 1 shows the electrical characteristics of the dielectric layer 8 on the composite substrate 10 manufactured as described above and the light emitting characteristics of the EL device manufactured using the composite substrate 10.

[0060]

[Table 1]

The electrical characteristics of the dielectric layer 8 were measured using a test substrate different from the EL device composite substrate. Instead of forming the light emitting layer 12 on the surface of the dielectric layer 8 in the composite substrate 10, the test substrate has a Pd paste of 1.5 mm width and a gap of 1.5 m on the surface of the dielectric layer 8 before firing.
After printing and drying in a m-striped pattern so as to be orthogonal to the striped pattern of the internal electrode layer 6, baking was performed at the above-mentioned temperature.

The electric characteristics of the dielectric layer 8 were measured by measuring the capacitance and the dielectric loss (tan δ) under the conditions of 1 KHz and 1 Vrms using an LCR meter, and the obtained capacitance, electrode dimensions and distance between the electrodes were obtained. From the relative permittivity (εr)
Was calculated. The dielectric strength was determined using an automatic booster.

The emission start voltage of the EL element was obtained by gradually applying a voltage from 0 V between the internal electrode and the transparent electrode of the EL element, and reading the voltage at which light emission was started with a voltmeter. In Table 1, those having no numerical value of the light emission start voltage indicate EL elements which did not start light emission even at 250V. The light emission luminance was measured by applying a voltage of 210 V to the EL element and making contact with the transparent electrode layer 16 to measure the color luminance (T).
OPCON product number BM-5A) was placed and measured.

Example 2 A dielectric paste for forming a dielectric layer was prepared by the following method, and the firing temperature of the composite substrate was adjusted to 1100.
C., and a composite substrate, an EL element, and a test substrate were prepared in the same manner as in Example 1 except that the thickness of the dielectric layer after firing was changed to 16 μm. Electric characteristics and emission characteristics of the EL element were measured. Table 1 shows the results.

In order to prepare the dielectric layer paste, first, BaTiO ₃ powder: 100 mol of BaTiO ₃ , 5 mol of Li ₂ SiO ₃ , and 0.1 mol of MnO.
19 mol, MgO: 2 mol, Y ₂ O ₃ : 2.1 mol, V ₂ O ₅ : 0.1 mol, (Ba _0.8 Ca
_{0.4) SiO} 3: 3 mol was added, mixing was performed in water. After the mixed powder was dried, it was mixed with a binder composed of ethyl cellulose and α-terpineol to prepare a dielectric paste.

Comparative Example 1 A composite substrate, an EL element and a test substrate were prepared in the same manner as in Example 2 except that the firing temperature of the composite substrate was 950 ° C. and the thickness of the dielectric layer after firing was 14 μm. Then, the electrical characteristics of the dielectric layer and the light emission characteristics of the EL element were measured in the same manner as in Example 1. Table 1 shows the results. In the EL element, no light emission was observed even when 210 V was applied.

Comparative Example 2 A composite substrate, an EL element and a test substrate were prepared in the same manner as in Example 2 except that the firing temperature of the composite substrate was 1350 ° C. and the thickness of the dielectric layer after firing was 15 μm. Then, the electrical characteristics of the dielectric layer and the light emission characteristics of the EL element were measured in the same manner as in Example 1. Table 1 shows the results. During firing of the composite substrate, the dielectric layer reacted with the substrate, and the relative permittivity, dielectric loss, and dielectric strength could not be measured.

Example 3 A composite substrate, an EL element and a test substrate were prepared in the same manner as in Example 1 except that the thickness of the dielectric layer after firing was 11 μm and the firing temperature of the composite substrate was 1200 ° C. Then, the electrical characteristics of the dielectric layer and the light emission characteristics of the EL element were measured in the same manner as in Example 1. Table 1 shows the results.

Example 4 The procedure of Example ₂ was repeated except that the amount of Li ₂ SiO ₃ added was 1 mol, the firing temperature of the composite substrate was 1200 ° C., and the thickness of the dielectric layer after firing was 12 μm. Then, a composite substrate, an EL element, and a test substrate were prepared, and the electrical characteristics of the dielectric layer and the emission characteristics of the EL element were measured in the same manner as in Example 1. Table 1 shows the results.

Example 5 The procedure of Example ₂ was repeated except that the amount of Li ₂ SiO ₃ added was 10 mol, the firing temperature of the composite substrate was 1200 ° C., and the thickness of the dielectric layer after firing was 17 μm. Then, a composite substrate, an EL element, and a test substrate were prepared, and the electrical characteristics of the dielectric layer and the emission characteristics of the EL element were measured in the same manner as in Example 1. Table 1 shows the results.

Example 6 The procedure of Example ₂ was repeated except that the amount of Li ₂ SiO ₃ added was 20 mol, the firing temperature of the composite substrate was 1200 ° C., and the thickness of the dielectric layer after firing was 15 μm. Then, a composite substrate, an EL element, and a test substrate were prepared, and the electrical characteristics of the dielectric layer and the emission characteristics of the EL element were measured in the same manner as in Example 1. Table 1 shows the results.

Example 7 K ₂ SiO ₃ was used in place of Li ₂ SiO ₃ , the amount added was 5 mol, and the firing temperature of the composite substrate was 1
A composite substrate, an EL element, and a test substrate were prepared in the same manner as in Example 2 except that the temperature was set to 200 ° C. and the thickness of the dielectric layer after firing was changed to 15 μm. And the emission characteristics of the EL element were measured.
Table 1 shows the results.

Example 8 Instead of Li ₂ SiO ₃ , Na ₂ SiO ₃ was used, the addition amount was 5 mol, and the firing temperature of the composite substrate was 1
A composite substrate, an EL element, and a test substrate were prepared in the same manner as in Example 2 except that the temperature was set to 200 ° C. and the thickness of the dielectric layer after firing was changed to 10 μm. And the emission characteristics of the EL element were measured.
Table 1 shows the results.

Example 9 Bi ₂ O ₃ was used in place of Li ₂ SiO ₃ ,
The addition amount was 5 mol, and the firing temperature of the composite substrate was 120.
A composite substrate, an EL element, and a test substrate were prepared in the same manner as in Example 2 except that the temperature was set to 0 ° C., and the thickness of the dielectric layer after firing was changed to 16 μm. And the emission characteristics of the EL element were measured. Table 1 shows the results.

Example 10 B ₂ O ₃ was used in place of Li ₂ SiO ₃ , the added amount was 5 mol, and the firing temperature of the composite substrate was 1200.
C., and a composite substrate, an EL element and a test substrate were prepared in the same manner as in Example 2 except that the thickness of the dielectric layer after firing was changed to 15 μm. Electric characteristics and emission characteristics of the EL element were measured. Table 1 shows the results.

Example 11 Using Al ₂ O ₃ instead of Li ₂ SiO ₃ ,
The addition amount was 5 mol, and the firing temperature of the composite substrate was 120.
A composite substrate, an EL device and a test substrate were prepared in the same manner as in Example 2 except that the temperature was set to 0 ° C. and the thickness of the dielectric layer after firing was changed to 10 μm. And the emission characteristics of the EL element were measured. Table 1 shows the results.

COMPARATIVE EXAMPLE 3 A dielectric layer was formed by sputtering to a thickness of 0.1 mm.
A composite substrate, an EL element, and a test substrate were prepared in the same manner as in Example 1 except that the thin film was composed of a 6 μm Y ₂ O ₃ thin film. Were measured for light emission characteristics. Table 1 shows the results.

[0078]Comparative Example 4 The thickness of the dielectric layer formed by the sputtering method is 0.1 mm.
6 μm Si₃O₄ Example 1 except that it was composed of a thin film
In the same manner as above, the composite substrate, the EL element, and the test substrate
The electrical characteristics and dielectric properties of the dielectric layer were prepared in the same manner as in Example 1.
And the emission characteristics of the EL element were measured. Table 1 shows the results.

As shown in Evaluation Table 1, the EL elements according to the examples use the dielectric layers of the high dielectric constant materials, and thus the comparative examples 3 and 4
The light emission starting voltage was lower than that of the EL device of No. 1, and the light emission luminance was higher under the same applied voltage. Further, by comparing Examples 2 and 3, it was confirmed that the emission luminance was increased by increasing the heat treatment temperature.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of an electroluminescent element according to the present invention.

[Explanation of symbols]

 2 electroluminescent element (EL element) 4 substrate 6 internal electrode layer 8 dielectric layer 10 composite substrate 12 light emitting layer 14 insulating layer 16 transparent electrode layer

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Daisuke Iwanaga 1-13-1 Nihonbashi, Chuo-ku, Tokyo FDT term in TDK Corporation (reference) 3K007 AB02 AB04 AB06 AB17 AB18 BA06 BB06 CA00 CA01 CA02 CB01 CC00 DA02 DA05 DB01 DB02 DC02 DC04 EC01 EC02 FA01 FA03 5C094 AA06 AA08 AA10 AA42 AA43 AA44 BA29 BA43 CA19 EA05 EB01 EB10 ED02 FB02 GB10 HA03 HA08

Claims (13)

[Claims] 1. An electrically insulating substrate, an electrode layer formed on the substrate, and barium titanate formed on the electrode layer and fired at a temperature higher than 1000 ° C. and lower than 1300 ° C. And a dielectric layer composed of a ceramic sintered body. 2. The composite substrate according to claim 1, wherein said dielectric layer contains an alkali component. 3. The method according to claim 2, wherein the alkali component is at least one of lithium oxide, potassium oxide and sodium oxide.
The composite substrate according to claim 2, comprising at least one species. 4. The composite substrate according to claim 1, wherein the dielectric layer contains at least one of silicon oxide, bismuth oxide, boron oxide, and aluminum oxide. 5. The barium titanate is made of BaTiO _3.
When converted to 100 moles, lithium silicate is converted to L
_2. The composite substrate according to claim 1, wherein the composite substrate includes the dielectric layer in a content of 0.1 to 20 mol in terms of i ₂ SiO ₃ . 6. The dielectric layer according to claim 1, wherein the dielectric layer comprises one of manganese oxide, magnesium oxide, yttrium oxide, vanadium oxide, tungsten oxide, silicon oxide, calcium oxide, zirconium oxide, niobium oxide and cobalt oxide.
The composite substrate according to claim 1, wherein the composite substrate includes at least one species. 7. An electrically insulating substrate, an electrode layer formed on the substrate, and barium titanate formed on the electrode layer and fired at a temperature higher than 1000 ° C. and lower than 1300 ° C. An electroluminescent device comprising: a dielectric layer formed of a ceramic sintered body; a light emitting layer formed on the dielectric layer; and a transparent electrode layer formed on the light emitting layer. 8. The electroluminescent device according to claim 7, wherein an insulating layer is interposed between the light emitting layer and the transparent electrode layer. 9. The electroluminescent device according to claim 7, wherein the dielectric layer contains an alkali component. 10. The method according to claim 1, wherein the alkali component is lithium oxide,
The electroluminescent device according to claim 9, comprising at least one of potassium oxide and sodium oxide. 11. The method according to claim 1, wherein the dielectric layer is made of one of silicon oxide, bismuth oxide, boron oxide and aluminum oxide.
2. The method according to claim 1, wherein the composition contains at least a species.
0. The electroluminescent device according to any one of 0. 12. The barium titanate is made of BaTiO.
9. The electroluminescent device according to claim 7, wherein lithium silicate is contained in the dielectric layer in a content of 0.1 to 20 mol in terms of Li ₂ SiO ₃ when converted to 100 mol in terms of _3. Sense element. 13. The method according to claim 1, wherein the dielectric layer contains at least one of manganese oxide, magnesium oxide, yttrium oxide, vanadium oxide, tungsten oxide, silicon oxide, calcium oxide, zirconium oxide, niobium oxide and cobalt oxide. An electroluminescent device according to any one of claims 7 to 12, wherein: