JP3073057B2 - Manufacturing method of electroluminescence device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an AC-driven thin-film electroluminescent device having a thin-film light-emitting layer made of at least one kind of phosphor on a sintered ceramic substrate and insulating layer having a high dielectric constant.

[0002]

2. Description of the Related Art Electroluminescent devices (hereinafter referred to as E)
L element) has been studied for a long time for application to a flat-panel solid-state light-emitting display device, and there is a strong expectation for its practical use. This EL device has a structure in which a crystalline thin film of a phosphor is formed on a glass or plastic film substrate, and a method of uniformly dispersing and mixing phosphor powder in an organic dielectric binder. It is classified into an organic dispersion type characterized by the feature and an inorganic dispersion type characterized by binding the phosphor powder with an inorganic binder such as glass. Inorganic dispersion type EL is often ceramic type EL
However, the phosphor powder particles are merely dispersed in the inorganic binder. Heretofore, with respect to the emission color of EL, yellow-orange emission in a ZnS: Mn-based double insulating structure AC-driven thin-film EL element and bluish green emission in a ZnS: Cu-based organic dispersion type AC-driven EL element have been put to practical use.

[0003]

However, since the conventional EL element uses a sulfide-based phosphor as the light emitting layer, passivation for use in an oxidizing atmosphere or an oxidizing atmosphere containing moisture is indispensable. It is expensive because of it. In addition, since the types of phosphors that can be used are limited, only the above-mentioned yellow-orange or blue-green light-emitting materials can be used. In the case of thin-film type, catastrophic dielectric breakdown due to high voltage application And in the case of the dispersion type, there is a problem that sufficient luminance for practical use cannot be obtained. For this reason, the conventional E
For the L element, the thin-film type is used only for limited applications such as expensive computer terminal displays, and the dispersed type has low luminance. It was only partially used for panels and the like.

[0004] In order to obtain a stable light emitting state with high luminance, high efficiency, and particularly in the case of a thin film EL device, it may be effective to improve the crystallinity of the light emitting layer.
As described above, the conventionally used substrate is made of glass or plastics, and thus has an essential problem that it cannot be processed at a temperature of 600 ° C. or higher.

According to the present invention, various phosphors such as existing oxyacid-based phosphors, oxide-based phosphors and sulfide-based phosphors which have not been effective for the purpose of multicoloring and practical use of EL devices have been hitherto used. We propose a method for making a thin film composed of at least one type sufficiently function as a light emitting layer for the EL element, and stably provide an AC-driven thin film EL element with high luminance, high efficiency, and stable desired color, full color or white light emission. And to provide a method for easy production.

[0006]

According to the present invention, as a means for solving the above-mentioned problems, a relative dielectric constant of 3,000 or more, preferably 4,000 or more, and a thickness of, for example, 0.04 to 0.7 mm (a value other than this thickness is used). possible is), preferably sintered ceramic substrate and the insulating layer of 0.1 to 0.4 mm [for example, barium titanate; BaTiO ₃
Sintered and lead magnesium _{niobate; Pb (Mg 1/3 Nb} 2/3) O
₃ etc.] and a commercially available oxyacid salt based phosphor, ie, CaWO ₄ based, Mg
WO ₄ system, YVO _4: Eu _{system, Y (PV) 0 4:} Eu system, Zn ₂ Si0 _4: Mn system, Zn ₂ S
iO ₄ : Ti system, MgSiO ₃ : Mn system, (Ca, Mg) SiO ₃ : Ti system, CaSiO ₃ : P
b, Mn system, (Sr, Mg) ₃ (PO ₄ ) ₂ : Sn system, Ca ₂ MgSi ₂ O ₇ : Ce system, Y ₂ Si
O _5: Ce system, Y ₂ SiO ₅ Tb _{based, Ca 2 P 2 O 7:} Dy _{system, (Zn, Ca) 3 (} P0 4) 2:
Mn-based, Ba ₂ P ₂ O ₇ : Ti-based, (Sr, Mg) ₂ P ₂ O ₇ : Eu-based, Ca ₁₀ (PO ₄ ) ₆ F
Cl: Sb, Mn, 3Ca ₃ (PO ₄ ) ₂・ Ca (F, Cl) ₂ : Sb, Mn, Sr ₁₀ (P
_{O 4) 6 FCl: Sb,} Mn _{system, Sr 5 (P0 4) 3} Cl: Eu system, (Sr, Ca, Ba) 5 (P
O ₄ ) ₃ Cl: Eu-based or (Ba, Ca, Mg) ₅ (PO ₄ ) ₃ Cl: Eu-based thin film composed of at least one phosphor, or ZnO: Zn-based, Y ₂
O ₃ : Eu system, La ₂ O ₂ S: Tb system, (Y, Gd) ₂ O ₂ S: Tb system, Y ₂ O ₂ S: Eu
System, Y ₃ Al ₅ O ₁₂ : Ce system, Y ₃ (Al, Ga) ₅ O ₁₂ : Ce system, BaMg ₂ Al ₁₆ O
₂₇ : Eu type, MgAl ₁₁ O ₁₉ : Ce, Tb, Mn type, 3.5Mg0 ・ 0.5MgF ₂・ Ge
O ₂ : Thin film or ZnS: Mn, ZnS: Rare earth system, ZnS: Ag system, ZnS:
Ag, Ni system, ZnS: Ag, Cu system, ZnS: Ag, Al system, ZnS: Ag, Ga, Cl
System, (ZnS, ZnSe): Ag system, ZnS: Cu system, ZnS: Cu, Al system, ZnS: C
u, Pb-based, ZnS: Cu, Au-based, ZnS: Au, Al-based, ZnS: Au, Ag, Al-based thin film composed of at least one sulfide-based phosphor, or various phosphors belonging to each of these systems Electron beam evaporation, activated reactive evaporation (ARE), sputtering, cluster ion beam (ICB), ion beam sputtering (IBS) , Chemical vapor deposition (CVD), atomic layer epitaxy (ALE), molecular beam epitaxy (MB
It can be formed in a vacuum or under various control atmospheres using a known crystal growth technique such as a method E), a gas source (MBE or CBE) method, or a crystal growth method utilizing electron cyclotron resonance (ECR). Thereafter, preferably, the thin film together with the substrate is embedded in a phosphor powder containing at least one component element constituting at least one phosphor constituting the thin film, and a non-oxidizing gas (e.g., argon, nitrogen, Non-oxidizing gas containing krypton, helium, etc. or partially oxidizing gas (e.g., oxygen, water vapor, air, etc.) or non-oxidizing gas containing partially reducing gas (e.g., hydrogen, carbon monoxide, ammonia, etc.) 600 ° C to 1 ° C in an atmosphere or an atmosphere equivalent to these atmospheres or in a vacuum
200 ° C, preferably 750 ° C to 1200 ° C, more preferably 90 ° C
By performing a heat treatment in a temperature range of 0 ° C. to 1050 ° C., the thin film is made to sufficiently function as a light emitting layer for an EL element. At this time, the formation of the thin film and the heat treatment can be performed at the same time, so that there is an advantage that the step is omitted. After forming a thin film in such a simultaneous process,
Further, heat treatment may be performed. Note that the heat treatment is preferably performed in an atmosphere at atmospheric pressure or reduced pressure.

A typical EL device according to the present invention basically comprises a transparent electrode layer 1, a thin film light emitting layer 2,
It comprises a sintered oxide ceramic substrate / insulating layer 3 and a back electrode layer 4. If necessary, various kinds of materials such as a ZnO thin film having conductivity and excellent environmental resistance are used as a charge supply layer between the thin film light emitting layer 2 and the substrate / insulating layer 3 or as a protective film of the substrate / insulating layer 3. It is effective to insert a single layer or a multilayer thin film. Further, in order to obtain a high contrast ratio, a black thin film can be formed or inserted between the thin film light emitting layer 2 and the substrate / insulating layer 3 as necessary. If necessary, an insulating or charge blocking layer may be inserted between the transparent electrode layer 1 and the thin-film light emitting layer 2 without any problem.

[0008]

In the method for manufacturing an EL device according to the present invention, a thin film made of at least one kind of phosphor is deposited on a sintered oxide ceramic substrate / insulating layer having a high relative dielectric constant of 3000 or more, preferably 4000 or more. By adopting the combination of forming, a high-temperature heat treatment of 600 ° C. or more, preferably 750 ° C. or more became possible. By employing this method, an AC-driven thin-film EL device comprising a high-quality light-emitting layer having excellent crystallinity can be easily manufactured, and as a result, an EL device having higher light emission luminance and higher light emission efficiency can be realized. The effect was obtained. An appropriate thickness of the thin film light emitting layer is, for example, 100 to 2000 nm. 100n
If it is less than m, the reliability of the device tends to be poor, and if it is more than 2000 nm, the light emission starting voltage of the device tends to be too high, but depending on the application, a thickness outside these ranges can be used.

The EL device according to the present invention uses a sintered oxide ceramic substrate having a high relative dielectric constant and an insulating layer as described above as an insulating layer, and therefore has excellent withstand voltage characteristics. In addition, an extremely high electric field can be effectively applied to the light-emitting layer without the fear of catastrophic dielectric breakdown, and the light-emitting center can be efficiently excited. In this case, it is more effective to use a bulk sintered oxide ceramic having a high relative dielectric constant, but this is not particularly limited.

The most significant effect of the present invention is that
CRT never applied as light emitting layer of L element
Alternatively, a wide variety of phosphors centering on oxyacid-based phosphors and oxide-based phosphors found in phosphors for lamps and the like are used.
The point is that it can be sufficiently activated as a light emitting layer for an L element. Simply replacing the light-emitting layer in the conventional EL device with the thin film made of the above-mentioned phosphor can reduce the E-value as conventionally believed.
Although it does not function effectively as a light emitting layer for an L element, the heat treatment method according to the present invention is applied to the phosphor thin film formed on the sintered oxide ceramic substrate / insulating layer, or the thin film formation and heat treatment are performed in the same step. This is the first point that the layer effectively functions as the EL element light emitting layer.

It is considered that these are caused by the following effects. 1) The crystallinity and structure of the compound base material of the phosphor thin film can be optimized. 2) The state of introduction of the luminescent center of the phosphor thin film can be optimized through a film forming process by the crystal growth technique or a subsequent high-temperature heat treatment at 600 ° C. or more, preferably 750 ° C. or more. 3) Damage to the sintered oxide ceramics of the insulating layer introduced during the process of forming the phosphor thin film can be recovered by the heat treatment step. Further, between the sintered oxide ceramic and the phosphor thin film light emitting layer, for example, various thin film layers having a thickness of 20 nm to 1 μm (a value other than this thickness is possible), preferably a thickness of about 50 nm to 500 μm. The insertion is effective as a buffer layer, a charge supply layer, a protection layer, or the like, and as a result, low voltage driving, high efficiency, and high emission luminance can be realized.

The significance of the fact that many phosphors, which have hardly been used as a light emitting layer for an EL device, can now function effectively by the manufacturing technique of the EL device according to the present invention is significant. This makes it possible to easily realize not only full-color display such as multi-color display of red, green, and blue light emission, but also white light-emitting EL elements, and wide application can be expected. Simply replacing the light emitting layer in the conventional EL element with a thin film made of a phosphor is not effective as a light emitting layer for an EL element as conventionally believed. As described above, the present invention relates to an EL device such as a surface-emitting type illuminating lamp, a surface-emitting type display panel, or a flat-panel display device having a flat light source.
An extremely innovative manufacturing technology is provided for the device. Hereinafter, the present invention will be described with reference to examples.

[0013]

(Example 1) A high-frequency magnetron in an argon gas atmosphere was used as a target with a powder of a Zn ₂ SiO ₄ : Mn (NO.P-1 phosphor) powder, which is an oxysilicate silicate phosphor. 800 nm thick Zn ₂ SiO ₄ : Mn on a sintered BaTiO ₃ ceramic substrate / insulating layer with a relative dielectric constant (εs) of 6000, thickness (t) of 0.2 mm and diameter (D) of 20 mm by sputtering. A thin film was formed. Then, in the oxide phosphor ZnO: Zn (NO.P-15 phosphor) powder charged in the alumina ceramic boat, Zn ₂ SiO ₄ : B with Mn
aTiO ₃ ceramics embedded, set in an electric furnace, 10
Heat treatment at 00 ° C. for 5 hours in an argon gas atmosphere,
A function as a light emitting layer for an EL element was imparted to the thin film. Then, on the light emitting layer, by magnetron sputtering method,
500 nm thick aluminum (Al) doped zinc oxide (ZnO: A
l) A transparent electrode layer was formed, and a metal Al back electrode layer was formed on the opposite surface by a vacuum deposition method, to produce an EL device.

As a result of driving this EL element with a sine wave AC voltage of 1 kHz, a light emission starting voltage of 90 V and a maximum light emission luminance of 2200 were obtained.
Uniform green light emission was obtained over the entire surface of the transparent electrode with cd / m ² (200 V applied) and luminous efficiency 1.0 lm / W. Further, as the sintered oxide ceramic substrate / insulating layer, εs = 12000, t =
In the surface smooth _{Pb (Mg 1/3 Nb 2} /3) O 3 sintered ceramics employing EL elements forming the same light-emitting layer of 0.15 mm,
Uniform green light emission was obtained over the entire surface of the transparent electrode at a light emission start voltage of 60 V, a maximum light emission luminance of 1200 cd / m ² (120 V applied), and a light emission efficiency of 0.1 lm / W. Further, on the BaTi0 ₃ ceramics, 50Nm～500n as a charge supply layer in advance sputtering
After forming a ZnO-based thin film of m thickness, Zn ₂ Si
O ₄ : In the case of a device having a Mn light emitting layer, the light emission starting voltage is 10
The voltage can be reduced by V to 30 V, and the same or higher EL characteristics can be realized. Further, in any of the above cases, the light emitting layer is formed of ZnO: Zn
System, La ₂ O ₂ S: Tb system, (Y, Gd) ₂ O ₂ S: Tb system, Y ₃ Al ₅ O ₁₂ : Ce system, Y
₃ (Al, Ga) ₅ O ₁₂ : Ce-based or Y ₂ SiO ₅ : Tb-based phosphor, etc. . Further, under substantially the same film-forming conditions, the light-emitting layer was replaced with Zn ₂ SiO ₄ : Mn by Zn ₂ SiO ₄ : Ti.
Uniform blue light emission was obtained over the entire surface of the transparent electrode at d / m ² (200 V applied) and luminous efficiency 0.2 lm / W. In addition, the light-emitting layer
Substantially the same characteristics were obtained by replacing with a, Mg) SiO ₃ : Ti.

Example 2 In a quartz reaction tube of an atmosphere-controlled horizontal tubular electric furnace having an external heater, a heated portion of 750 ° C. was heated to a sintered surface of 25 mmφ × 0.2 mm in thickness and having a relative dielectric constant of 6200. _{(3) A} ceramic substrate / insulating layer is set, and a raw material gas introduction quartz tube nozzle containing Si having an inner diameter of 4 mmφ is placed near the substrate from a gas introduction port which is one end of the reaction tube,
The substrate was placed at an angle so that the flow of the introduced raw material gas on the substrate became laminar.

On the other hand, a quartz tube for introducing a raw material gas containing zinc was drawn in parallel to the quartz tube for introducing a Si raw material to the vicinity of the substrate. At that time, zinc acetate (Zn (CH ₃ COO) ₂ ) powder was previously loaded as a zinc raw material in the 350 ° C. soaking part. Then, a quartz tube for introducing a raw material gas containing a titanium (Ti) dopant as an emission center was drawn almost in parallel to the above-described quartz tube for introducing a raw material and similarly to the vicinity of the substrate. In order to control the gas partial pressure and the reaction in the reaction tube, an air introduction tube was disposed near the raw material gas introduction port, and a vacuum exhaust system was set on the opposite side of the reaction tube.

The Si raw material was sent to the introduction pipe by flowing a nitrogen carrier gas through a bubbler placed outside the furnace and containing tetraethylorthosilicate (commonly called tetraethoxysilane; TEOS). At this time, air and nitrogen gas are oxidizing gas
It acted as a non-oxidizing gas (nitrogen gas) atmosphere partially containing (air). On the other hand, an argon carrier gas was used to transport the zinc raw material, and a Ti dopant was introduced into a bubbler containing tetraisopropyl titanate (Ti (OC ₃ H ₇ ) ₄ ) outside the furnace using the argon carrier gas. Led to the tube.

Using this apparatus, a reduced pressure MOCV under a pressure of 1 Torr was used.
By method D, a Ti-doped zinc silicate (Zn ₂ SiO ₄ : Ti) thin film having a thickness of about 450 nm was formed on the substrate. Then, a 500 nm-thick aluminum (Al) -doped zinc oxide (ZnO: Al) transparent electrode layer was formed on the light-emitting layer by magnetron sputtering, and a metal Al back electrode layer was formed on the opposite surface by vacuum evaporation. Each was formed to produce an EL element. As a result of driving this EL element with a sine wave AC voltage of 1 kHz, a light emission starting voltage of 120 V, a maximum light emission luminance of 1200 cd / m ² (200 V applied),
Uniform blue light emission was obtained over the entire surface of the transparent electrode at a luminous efficiency of 0.2 lm / W. In addition, the heat treatment performed under the same conditions as in Example 1 (800 ° C. only at the temperature) after the formation of the Zn ₂ SiO ₄ : Ti thin film also showed extremely good results.

(Embodiment 3) εs = 4600, t = 0.3 mm, D = 20
mm in surface smoothness sintered BaTi0 ₃ ceramic substrate and an insulating layer of an oxide-based phosphor Y ₂ O _3: Eu system of (NO.P-56 phosphor) powder compact pellet by electron beam evaporation , Thickness 6
A thin film of Y ₂ O ₃ : Eu having a thickness of 00 nm was embedded in P-56 phosphor powder charged in an alumina ceramic boat, set in an electric furnace, and heat-treated at 1000 ° C. for 2 hours in an argon gas atmosphere. The thin film was given a function as a light emitting layer for an EL element. Thereafter, the same transparent electrode as in Example 1 was formed on the light-emitting layer, and a metal Al back electrode was formed on the opposite surface by a vacuum evaporation method, to produce an EL device.

As a result of driving this EL element with a sine wave AC voltage of 1 kHz, a light emission start voltage of 60 V and a light emission luminance of 2500 cd /
Uniform red light emission was obtained over the entire surface of the transparent electrode at m ² (200 V applied) and luminous efficiency 1.1 lm / W. Further, the above light emitting layer, MgSiO ₃ : Mn system, CaSiO ₃ : Pb, Mn system, (Zn, Ca) ₃ (PO ₄ ) ₂ : Mn
Even if it was replaced with a thin film made of a phosphor such as a YVO ₄ : Eu-based phosphor, almost the same color, which appeared red with the naked eye, was obtained.

(Embodiment 4) εs = 4600, t = 0.3 mm, D = 20
An oxide-based phosphor Y ₂ O ₃ : Eu-based (NO.P-56 phosphor) powder compact was used as a target on a sintered BaTiO ₃ ceramic substrate / insulating layer with a smooth surface of 400nm in thickness by high frequency magnetron sputtering method
Y ₂ O ₃ : Eu phosphor thin film on which oxylate-based
A Zn ₂ SiO ₄ : Mn thin film was formed by laminating a 500 nm thick Zn ₂ SiO ₄ : Mn thin film by high-frequency magnetron sputtering in the same manner as in Example 1, and the same amount as P-56 charged in an alumina ceramic boat was used. It is embedded in the P-1 phosphor mixed powder, set in an electric furnace, and heat-treated at 1000 ° C. for 5 hours in an argon gas atmosphere or a nitrogen gas-diluted ammonia gas atmosphere. Function was added. Thereafter, the same transparent electrode layer as in Example 1 was formed on the light emitting layer, and a metal Al back electrode was formed on the opposite surface by a vacuum deposition method, respectively, to produce an EL device.

As a result of driving this EL device with a sine wave AC voltage of 1 kHz, a light emission starting voltage of 90 V and a light emission luminance of 1500 cd /
m ² (200 V applied) and luminous efficiency of 0.3 lm / W, uniform yellow light emission was obtained by mixing red and green over the entire surface of the transparent electrode.

(Embodiment 5) εs = 5000, t = 0.25 mm, D = 2
A high-frequency magnetron sputtering method (type A method) targeting a sulfide-based phosphor, ZnS: Mn-based powder compact, on a 0 mm surface smooth sintered BaTiO ₃ ceramic substrate / insulating layer, and an organic metal By a chemical vapor deposition (MOCVD) method (referred to as a type B method), ZnS having a thickness of about 420 nm
The pellet formed with the thin film composed of the Mn phosphor was embedded in ZnS: Mn phosphor powder charged in an alumina ceramic boat and set in an electric furnace, and the sputtered film was heated at 900 ° C. for 5 hours.
The OCVD film was subjected to a heat treatment at 800 ° C. for 5 hours in an atmosphere of argon gas to give the thin film a function as a light emitting layer for an EL element. Thereafter, the same transparent electrode layer as in Example 1 was formed on the light emitting layer, and a metal Al back electrode was formed on the opposite surface by a vacuum deposition method, respectively, to produce an EL device.

Each of the EL devices prepared from the thin films obtained by the type A method and the type B method was driven by a sinusoidal AC voltage of 1 kHz. As a result, the light emission starting voltage was 30 V, and the light emission luminance was 5000 cd / m. ² (200V applied), luminous efficiency 4.0 lm / W, luminous luminance 9000 cd / m ² (200V applied), luminous efficiency 6.0 lm / W for the device by the type B method
In each case, uniform yellow-orange emission was obtained over the entire surface of the transparent electrode, and the temporal stability was significantly improved. Further, even when the above-mentioned light emitting layer was replaced with a thin film composed of a (ZnS, ZnSe): Mn phosphor, substantially the same light emission as that of yellowish orange was obtained with the naked eye.

(Embodiment 6) εs = 5600, t = 0.15 mm, D = 2
On a sintered BaTiO ₃ ceramic substrate / insulating layer with a surface smoothness of 0 mm, an oxide-based phosphor Y ₂ O ₂ S: Eu (NO.P-22) Thickness in a mixed gas atmosphere by high-frequency magnetron sputtering
600nm of Y ₂ O ₂ S: a thin film made of Eu phosphor, a further sulphide phosphor thereon ZnS: Ag and target (NO.P-55) phosphor powder compact, an argon gas atmosphere A 400 nm thick ZnS: Ag phosphor thin film formed by magnetron sputtering at was embedded in the same amount of P-22 phosphor mixed powder as the P-55 phosphor powder charged into the alumina ceramic boat It was set in an electric furnace and heat-treated at 900 ° C for 5 hours in an argon gas atmosphere.
A function as a light emitting layer for an L element was provided. Thereafter, the thickness of the light emitting layer was reduced to 25 mm by a high-frequency magnetron sputtering method.
An EL element was manufactured by forming a ZnO: Al transparent electrode layer of 0 nm and a metal Al back electrode on the opposite surface by a vacuum evaporation method.

As a result of driving this EL element with a sine wave AC voltage of 1 kHz, a light emission starting voltage of 70 V and a light emission luminance of 1000 cd /
Uniform blue-white light emission was obtained over the entire surface of the transparent electrode with m ² (120 V applied) and luminous efficiency of 0.1 lm / W.

(Embodiment 7) εs = 6500, t = 0.25 mm, D = 2
A sulfide-based phosphor, ZnS: Ag + ZnS: Au, Al + Y ₂ O ₂ S: Eu, is formed on a 0 mm surface smooth sintered BaTiO ₃ ceramic substrate / insulating layer.
440 nm thick ZnS: A by high-frequency magnetron sputtering with a target (NO.P-4 phosphor) powder compact
g + ZnS: Au, Al + Y ₂ O ₂ S: Eu formed a thin film consisting of the phosphor was embedded in a P-4 phosphor powder charged in an alumina ceramic boat, set in an electric furnace, at 900 ℃ 5 hours,
Heat treatment was performed in an argon gas atmosphere to give the thin film a function as a light emitting layer for an EL element. Thereafter, the same transparent electrode layer as in Example 1 was formed on the light-emitting layer, and a metal Al back electrode was formed on the opposite surface by a vacuum evaporation method.
An element was manufactured.

As a result of driving this EL element with a sine wave AC voltage of 1 kHz, a light emission starting voltage of 75 V and a light emission luminance of 1700 cd
/ m ² (applied to 160 V) and a luminous efficiency of 0.2 lm / W, uniform white light emission was obtained over the entire surface of the transparent electrode. Further, the light-emitting layer, ZnS: Au + ZnS: Ag , Al (NO.P-4 phosphor) _{system, Y 2 O 2 S: Tb} (NO.
Even when replaced with a thin film made of a phosphor such as a (P-45 phosphor) system, almost the same, light emission that appeared white to the naked eye was obtained.

Example 8 εs = 5500, t = 0.25 mm, D = 2
A sulfide-based phosphor, ZnS: Ag + ZnS: Au, Al + Y ₂ O ₂ S: Eu, is formed on a 0 mm surface smooth sintered BaTiO ₃ ceramic substrate / insulating layer.
(NO.P-4 phosphor) powder compact
(S) While introducing a gas and maintaining the partial pressure ratio at 20%, a 440 nm thick Z
nS: Ag + ZnS: Au, Al + Y 2 O 2 S: forming a thin film made of Eu phosphor. Thereafter, heat treatment was performed at 850 ° C. for 5 hours in an argon gas atmosphere to give the thin film a function as a light emitting layer for an EL element. Thereafter, a ZnO: Al transparent electrode layer having a thickness of 25 nm was formed on the light emitting layer by a high-frequency magnetron sputtering method,
On the other side, a metal Al back electrode was formed by a vacuum evaporation method to produce an EL element.

As a result of driving this EL element with a 1 kHz sinusoidal AC voltage, a light emission starting voltage of 95 V and a light emission luminance of 2300 cd /
Uniform white light emission was obtained over the entire surface of the transparent electrode with m ² (150 V applied) and luminous efficiency of 0.4 lm / W. Even if the above-mentioned light emitting layer is replaced with a thin film made of a phosphor of ZnS: Au + ZnS: Ag, Al system, Y ₂ O ₂ S: Tb system, etc. Obtained.

(Embodiment 9) εs = 6200, t = 0.15 mm, D = 2
On one side (referred to as type A) and both sides (referred to as type B) on a sintered BaTiO ₃ ceramic substrate / insulating layer having a surface smoothness of 0 mm, an oxygenate-based halophosphate phosphor, Ca ₁₀ (PO ₄ ) ₆ F
Pellets on which a Ca ₁₀ (PO ₄ ) ₆ FCl: Sb, Mn thin film having a thickness of 450 nm was formed by a high-frequency magnetron sputtering method in an argon gas atmosphere using a Cl: Sb, Mn-based powder compact as a target. Thereafter, the pellets were buried in the phosphor powder charged in an alumina ceramic boat, set in an electric furnace, heat-treated at 900 ° C. for 5 hours in an oxygen / argon mixed gas atmosphere, and EL was applied to the thin film.
A function as a light emitting layer for an element was provided. Thereafter, a 750 nm thick ZnO: Al transparent electrode layer is formed on the surface of the type A light emitting layer and the substrate / insulating layer side, and on both surfaces of the type B light emitting layer by a high-frequency magnetron sputtering method, An EL device made entirely of oxide was produced.

As a result of driving this EL element with a sine wave AC voltage of 1 kHz, the EL element of type A emits light at 70 V, and the EL element of type B emits light at 120 V and emits light at 1500 cd / m ² (220 V). Applied), luminous efficiency
At 0.2 lm / W, uniform white light emission was obtained over the entire surface of the transparent electrode. Further, the above light emitting layer is made of (Sr, Mg) ₂ P ₂ O ₇ : Eu based, S
r ₅ (PO ₄ ) ₃ Cl: Eu, (Sr, Ca, Ba) ₅ (PO ₄ ) ₃ Cl: Eu, CaWO
₄ system, CaWO ₄ : Pb system, when replaced with a thin film composed of a phosphor such as MgWO ₄ system, it looks blue to the naked eye, almost the same emission characteristics, Ba ₂ P ₂ O ₇ : Ti system, Zn ₂ SiO ₄ : Mn-based, MgAl ₁₁ O ₁₉ : Ce, Tb,
When replaced with a thin film made of a phosphor such as Mn-based material, it looks green to the naked eye and has almost the same emission characteristics, and Y (PV) O ₄ : Eu
When replaced with a thin film composed of a phosphor such as a 3.5MgO.0.5MgF ₂ .GeO ₂ : Mn-based or Y ₂ O ₃ : Eu-based phosphor, almost the same luminescence was obtained which appeared red to the naked eye.

In the above embodiment, the thin film light emitting layer is formed by a high frequency magnetron sputtering method, an electron beam evaporation method or an MOCVD method, but an existing crystal growth technique such as a CVD method using a halide or an MBE method is used. it can. Furthermore, in addition to the ZnO: Al transparent electrode exemplified in the above embodiment, tin oxide (SnO ₂ ) and indium tin oxide (ITO)
Use of a system or other various transparent conductive films is not a problem. When the light emitting layer is manufactured by the MOCVD method, it is effective to form a conductive film having excellent hydrogen resistance such as ZnO: Al on the sintered ceramic substrate / insulating layer as a protective film of the substrate. It is.

[0034]

According to the present invention, various types of materials which have not heretofore been usable as a light emitting layer material of an EL device, or were not characteristically usable as a light emitting layer material, or were insufficient in characteristics. It can provide a way to use phosphors, especially oxide-based phosphors, and the effect is enormous. That is, at least one of various phosphors such as oxyphosphate-based phosphors, oxide-based phosphors, and sulfide-based phosphors known as existing phosphors for electron tubes and lamps functions as a light-emitting layer for an EL element. As a result of establishing the manufacturing method, it is possible to realize light emission of desired colors such as white light emission as well as light emission of each color such as red, green, and blue, and full color light emission irrespective of the kind of the fluorescent substance so far. As a result, it can be used as an EL element for a light emitting type flat display, or an illuminating lamp utilizing a feature of a surface light emitting element, various application devices using a liquid crystal display device which requires various pattern displays or a flat light source, and a commercial power supply type light emitting device. It can be used in various fields, such as exerting a great deal of power on the element, and has the effect of creating a wide range of unprecedented applications.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a structural example of an EL element according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent electrode layer 2 Thin film light emitting layer 3 Sintered oxide ceramic substrate and insulating layer 4 Back electrode layer

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H05B 33/10

Claims (10)

(57) [Claims] 1. A thin film made of at least one kind of phosphor is formed on one side or both sides on a sintered oxide ceramic plate having a relative dielectric constant of 3000 or more, which is a substrate / insulating layer,
After the thin film is formed, a sufficient heat treatment is performed in an appropriate atmosphere at a temperature of 600 ° C. to 1200 ° C. to give the thin film a sufficient function as a light emitting layer for an electroluminescence element. In the method for producing an AC-driven thin-film electroluminescent element formed with a take-out transparent electrode layer, the thin film made of the phosphor is a mixture of at least one kind of oxyacid-based phosphor and at least one kind of oxide-based phosphor. A method for producing an AC-driven thin-film electroluminescent device, comprising a single-layer thin film or a multilayer thin film obtained by laminating respective thin films of the oxyacid-based phosphor and the oxide-based phosphor. 2. The method of manufacturing an AC-driven thin-film electroluminescent device according to claim 1, wherein said heat treatment is performed in a vacuum instead of in an appropriate atmosphere. 3. The alternating current according to claim 1, wherein the heat treatment is performed in an atmosphere of a non-oxidizing gas containing a non-oxidizing gas or a partially oxidizing gas, or a non-oxidizing gas containing a partially reducing gas. A method for manufacturing a driving thin-film electroluminescence device. 4. The AC-driven thin film electroluminescent device according to claim 1, wherein various thin film layers of 20 nm to 1 μm are inserted on the ceramic plate before forming the thin film made of the phosphor. Manufacturing method. 5. A thin film made of at least one kind of phosphor is formed on one side or both sides on a sintered oxide ceramic plate having a relative dielectric constant of 3000 or more, which is a substrate / insulating layer,
After the thin film is formed, a sufficient heat treatment is performed in an appropriate atmosphere at a temperature of 600 ° C. to 1200 ° C. to give the thin film a sufficient function as a light emitting layer for an electroluminescence element. In the method for producing an AC-driven thin-film electroluminescence device having a take-out transparent electrode layer, the thin film made of the phosphor may be at least one kind of an oxyacid-based phosphor or an oxide-based phosphor and a sulfide-based phosphor. A method for producing an AC-driven thin-film electroluminescent device, which has a two-layer structure with a body or a three-layer structure in a sandwich shape, or has a multilayer structure in which both are alternately laminated. 6. The method according to claim 5, wherein the heat treatment is performed in a vacuum instead of in an appropriate atmosphere. 7. The alternating current according to claim 5, wherein the heat treatment is performed in an atmosphere of a non-oxidizing gas containing a non-oxidizing gas or a partially oxidizing gas, or a non-oxidizing gas containing a partially reducing gas. A method for manufacturing a driving thin-film electroluminescence device. 8. The AC-driven thin-film electroluminescent device according to claim 5, wherein various thin-film layers of 20 nm to 1 μm are inserted on the ceramic plate before forming the thin film made of the phosphor. Manufacturing method. 9. A thin film made of at least one kind of phosphor on a sintered oxide ceramic plate having a relative dielectric constant of 3000 or more, which is both a substrate and an insulating layer, in a temperature range of 600 ° C. to 1200 ° C. in an appropriate atmosphere. Is formed on only one side or both sides, thereby imparting the thin film with a sufficient function as a light emitting layer for an electroluminescent element, and an AC-driven thin film electro-electrode comprising a light extraction transparent electrode layer formed on the thin film. In the method for manufacturing a luminescence element, the thin film made of the phosphor is a single-layer thin film of a mixture of at least one kind of oxyacid-based phosphor and at least one kind of oxide-based phosphor, or the oxyacid-based phosphor and A method for manufacturing an AC-driven thin-film electroluminescent device, comprising a multilayer thin film formed by stacking respective thin films of an oxide-based phosphor. 10. A thin film made of at least one kind of phosphor on a sintered oxide ceramic plate having a relative dielectric constant of 3000 or more, which is both a substrate and an insulating layer, in a temperature range of 600 ° C. to 1200 ° C. in an appropriate atmosphere. Is formed on only one side or both sides, thereby imparting the thin film with a sufficient function as a light emitting layer for an electroluminescent element, and an AC-driven thin film electro-electrode comprising a light extraction transparent electrode layer formed on the thin film. In the method for manufacturing a luminescence element, the phosphor thin film has a two-layer structure or a sandwich-like three-layer structure of at least one kind of oxyacid-based phosphor or oxide-based phosphor and a sulfide-based phosphor. A method for manufacturing an AC-driven thin-film electroluminescent device, comprising: