JP3036097B2 - EL device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescent device (electroluminescent light emitting device).

[0002] More specifically, the present invention relates to an electroluminescent device having good light emission luminance and efficiency and excellent durability.

[0003]

2. Description of the Related Art Conventionally, an electroluminescent device in which a high dielectric constant layer, a light emitting layer and a transparent electrode layer are laminated on an electrode layer is known. Examples of the high dielectric constant layer include barium titanate and strontium titanate. In addition, a powder obtained by dispersing a high dielectric constant inorganic powder such as lead titanate in a cellulose-based high dielectric binder such as cyanoethyl cellulose is used. Further, as the light emitting layer, a material in which phosphor powder such as zinc sulfide doped with copper, manganese, or aluminum is dispersed in a cellulose-based high dielectric binder such as cyanoethyl cellulose is used. I have.

[0004]

However, the conventional electroluminescent device has the following problems.

That is, a high dielectric constant inorganic powder such as barium titanate, strontium titanate, or lead titanate used as a high dielectric constant layer is applied to cyanoethyl cellulose.
Phosphor powder such as zinc sulfide doped with copper, manganese, aluminum or the like, which is dispersed in a cellulosic high dielectric binder such as copper, or used as a light emitting layer. Those dispersed in a cellulosic high dielectric binder such as a glass have a problem that the light emission luminance is reduced by adsorbing moisture, a transparent electrode layer and a light emitting layer, or a high dielectric constant layer. There has been a problem that adhesion to the electrode layer is poor and uneven light emission occurs.

[0006] In order to solve these problems, with respect to the improvement of the moisture-proof property, a method of forming an inorganic moisture-proof layer on a fluorine film (Japanese Patent Laid-Open No. 2-229032), and to improve the adhesion, a transparent electrode layer is formed. Forming a palladium layer on the substrate (Japanese Patent Application Laid-Open Nos. 64-81112 and 2-72294)
0, JP-A-2-98436) have been proposed.

However, it is difficult to completely reduce the moisture permeability to zero. Further, regarding the formation of the palladium layer, it is possible to improve the adhesion and to prevent a decrease in emission luminance to some extent,
By forming the palladium layer, light emission luminance is reduced and power consumption is increased, that is, efficiency is reduced.

However, the present inventors have found that the above problems can be solved by adding palladium to the high dielectric constant layer and / or the light emitting layer as in the present invention, and have reached the present invention.

[0009]

That is, the present invention relates to an electroluminescent device comprising an electrode layer, a high dielectric constant layer, a light emitting layer, a transparent electrode layer, and a protective sheet enclosing these layers. Fine particles of palladium having an average particle size of 30 μm or less in one or both of the layers have a content of 0.001 to 5 with respect to all materials constituting the high dielectric constant layer and the light emitting layer.
Provided is an electroluminescent device characterized in that the electroluminescent device is contained in an amount of 0.1 wt%.

As the electrode layer of the present invention, an aluminum foil of 10 to 50 μm is mainly used, but the electrode layer is not limited to this. For example, silver paste or the like may be applied to a plastic film such as a copper foil or polyester of 10 to 50 μm to form an electrode layer.

The high dielectric layer is made of a high dielectric powder such as barium titanate, lead titanate or strontium titanate.
A high dielectric binder such as cyanoethyl cellulose, sucrose, cyanoethyl pullulan, and cellulose acetate is dispersed in a solvent such as dimethylformamide to form a paint. The coating is applied and dried by a method such as printing.

The light emitting layer is made of a phosphor such as zinc sulfide doped with copper or aluminum, and is made of cyanoethyl cellulose.
, Sucrose, cyanoethyl pullulan, cellulose acetate and other high dielectric binders are dissolved in a solvent such as dimethylformamide to form a paint, and the high dielectric layer is screened to a thickness of 10 to 50 μm. It is formed by applying and drying by a method such as printing.

One of a high dielectric constant layer and a light emitting layer;
Alternatively, fine palladium powder having an average particle size of 30 μm or less is added to both of them. The amount of palladium fine powder to be added is based on all materials constituting the high dielectric constant layer and the light emitting layer.
0.001 to 5 wt%. Preferably, 0.002
１1 wt%, more preferably 0.005 to 0.1 w
t%. When the addition amount of palladium is small, the life of the electroluminescent element, that is, the light emission luminance is quickly reduced. Also,
If the amount of added palladium is too large, the luminous efficiency of the electroluminescent device will be reduced, and the power consumption will be increased at the same luminance. The amount of addition in each of the high dielectric constant layer and the light emitting layer is 5 wt% or less, more preferably 1% by weight, based on the material constituting each layer.
wt% or less, more preferably 0.1 wt% or less.

The average particle size of the palladium particles added to the high dielectric constant layer and / or the light emitting layer needs to be 30 μm or less. The particle size is preferably 15 μm or less, and more preferably 5 μm or less. If the average particle size of palladium exceeds 30 μm, problems such as short-circuiting tend to occur, which is not preferable.

When the average particle size of palladium is X (μm), and the concentration of added palladium with respect to all materials constituting the high dielectric constant layer and the light emitting layer is Y (wt%), the formula (X / 3
0) ≦ Y ≦ (X / 6).

The transparent electrode layer is formed on one side of a polyester film by forming a transparent conductive layer made of indium oxide-tin composite oxide (ITO) by a method such as vacuum deposition and sputtering, and further provides adhesion to the light emitting layer. Therefore, an easy-adhesion layer is provided as needed. Examples of the easily adhesive layer include JP-A-64-81112, JP-A-2-72940, and JP-A-2-72940.
The technique described in -98436 can be used. This transparent electrode layer is laminated with the light emitting layer by a method such as pressure pressing.

The protective sheet covers the entirety of the electrode layer, the high dielectric constant layer, the light emitting layer, and the transparent electrode layer.
A film in which a vinyl acetate copolymer resin is laminated is generally used, but is not necessarily limited thereto.
If necessary, a water trapping layer such as a polyamide film may be included between the transparent electrode and the back electrode layer and the protective sheet. Further, electrodes are respectively provided from the transparent electrode and the back electrode layer.

[0018]

EXAMPLE A high dielectric constant layer having a coating composition of each of the following four compositions shown in Table 1 was formed to a thickness of 35 .mu.m on a 50 .mu.m aluminum foil (manufactured by Showa Aluminum Co., Ltd.) washed with acetone.

For barium titanate, BT-300 manufactured by Rhone-Pulan was used, and for cyanoethyl pullulan, CR-S manufactured by Shin-Etsu Chemical Co., Ltd. was used. Reagents (special grade) were used for dimethylformamide and acetone.

[0020]

[Table 1]

Next, on the high dielectric layer having the composition shown in Table 1, a light emitting layer having the coating composition shown in Table 2 was coated with 35 μm.
m thickness.

The phosphor in the light emitting layer is TYP of Sylvania.
E830 was used.

[0023]

[Table 2]

Further, a transparent electrode (a transparent conductive film "HIBIM" 75 manufactured by Toray Industries, Inc.) on which an extraction electrode is set.
L-CF98) and the intermediate element.
Temporary lamination was performed. Lastly, ethylene trifluoride chloride film (Nitoflon No.4810 manufactured by Nitto Denko Corporation)
This lamination was performed to obtain an electroluminescent device.

0.002 wt% palladium in the high dielectric constant layer
%, (Example 2), 0.02 wt% added (), Example 2, and 0.2 wt% added ().

Also, 0.002 w of palladium is added to the light emitting layer.
Example 4 was obtained by adding t% (), Example 5 was obtained by adding 0.02 wt% (), and Example 6 was obtained by adding 0.2 wt% ().

The palladium used had a purity of 99.9% and an average particle diameter of 10 μm manufactured by Tanaka Kikinzoku Co., Ltd.

The initial luminance of this electroluminescent device at 900 Hz and 100 V, the efficiency at 200 nt, and 50
900Hz after leaving for 500 hours
The luminance at 0 V and the efficiency at 200 nt were measured. Table 3 shows the results.

[0029]

[Table 3]

[0030]

Comparative Example A high dielectric constant layer having a coating composition shown in Table 1 having a thickness of 35 μm was formed on a 50 μm aluminum foil (manufactured by Showa Aluminum Co., Ltd.) washed with acetone.

Next, on the high dielectric layer having the composition shown in Table 1, a light emitting layer having the coating composition shown in Table 2 was formed to a thickness of 35 μm.

Further, a transparent electrode (a transparent conductive film "HIBIM" 75 manufactured by Toray Industries, Inc.) on which an extraction electrode is set.
L-CF98) and the intermediate element.
Temporary lamination was performed. Lastly, ethylene trifluoride chloride film (Nitoflon No.4810 manufactured by Nitto Denko Corporation)
This lamination was performed to obtain an electroluminescent device. This is referred to as Comparative Example 1.

Further, the transparent electrode of Comparative Example 1 was replaced with a transparent conductive film in which only an ITO layer was formed on a 75 μm polyethylene terephthalate film. Table 3 shows the results.

[0034]

The electroluminescent device of the present invention can be widely used in fields such as planar illumination and display. Among them, it can be used for a backlight of a liquid crystal display element or a liquid crystal television, a curved surface display, a panel display of a car, a train, or the like.

The electroluminescent device of the present invention has a higher luminance and efficiency than the conventional electroluminescent device because of its excellent light emission luminance and efficiency and excellent durability.

Since the efficiency is good, power consumption is low at the same luminance.

Because of excellent durability, light emission luminance is maintained for a long time. And the like.

As described above, the effect is exhibited because palladium added to the high dielectric constant layer or the light emitting layer reacts with the moisture that has invaded the electroluminescent element, and the ZnS of the light emitting layer
It is presumed that it functions to prevent the deterioration of for that reason,
For example, a hydrogen storage alloy is considered to have a similar effect.

Claims (1)

(57) [Claims] 1. An electroluminescent device comprising an electrode layer, a high dielectric constant layer, a light emitting layer, a transparent electrode layer, and a protective sheet,
Fine particles of palladium having an average particle size of 30 μm or less in either one or both of the high dielectric constant layer and the light emitting layer are used in an amount of 0.00% with respect to all materials constituting the high dielectric constant layer and the light emitting layer.
An electroluminescent device characterized by containing 1 to 5 wt%.