JPH09148074A - Electroluminescent display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroluminescent display device having high adhesive strength and low resistance by laminating a transparent conductive laminated body composed of an organic high polymer base body, a transparent electrode layer and a metallic layer having the specified thickness to a luminescent layer laminated body. SOLUTION: A transparent conductive layer 3 formed of at least one oxide of In, Sn, Sb is formed on a high heat resistant organic high polymer base body 2 of polyimide by using a sputtering method or a reaction depositing method. A metallic layer 4 of In, Sn, Cd is attached on the transparent conductive layer 3 by the thickness of 200Å or more by a sputtering method or a depositing method. After the metallic layer 4 and the transparent conductive layer 3 are overlapped, cut, etched and patterned by using the specified mask as necessary, an obtained transparent conductive laminated body 1 is stuck to a laminated body 5 composed of a metallic electrode layer 6, an insulating layer 7 and a luminescent layer 8 by pressurizing and heating rollers 9 through the metallic layer 4 and the luminescent layer 8. Therefore, an electroluminescent display device having the light transmission factor, and in which luminous unevenness is not easily generated is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescence display device.

[0002]

A transparent conductive film or a transparent conductive laminate is used, for example, as an electrode for a liquid crystal display, an electrode for an electroluminescent display device, an electrode for a photoconductive photoreceptor, a cathode ray tube, and various measurements. BACKGROUND ART A transparent conductive film (transparent conductive laminate) is widely used in the electric and electronic fields such as an electrostatic shielding layer of a window portion of a container, an antistatic layer, and a heating element.

[0003] Of these, the transparent conductive laminate having selective light transmittance is applied as a window material for a collector for utilizing solar energy or as a window material of a building due to its infrared light reflectivity. . In addition, with the development of information processing, various solid-state displays using electroluminescence, liquid crystal, plasma, and ferroelectric have been developed as display devices to replace cathode-ray tubes. Transparent electrodes are always used for these displays.

Further, new electro-optical elements and recording materials based on the interaction or mutual conversion between electric signals and optical signals are considered useful for future information processing technology. A combined membrane is required. On the other hand, such a transparent conductive laminate can be used as a window glass for preventing condensation in automobiles and airplanes, or as an antistatic film of polymer or glass, or as a transparent heat insulating window for preventing diffusion of solar energy. .

In particular, in recent years, there has been an increasing demand for high pixel display in liquid crystal displays, electroluminescence, plasma displays, electrochromic displays, fluorescent display devices, and the like. Accordingly, a pixel portion is formed by an electrode made of a transparent conductive layer. In addition, it has been proposed that a signal application line is formed by a low-resistance electrode made of a metal layer to improve an image display speed and an image.

However, in the conventional electroluminescent display device, the resistance of the electrode is not sufficiently reduced, and the adhesive strength between the electroluminescent light emitting layer and the transparent conductive layer is insufficient. Happens,
It has been found that there are problems such as uneven light emission during operation. Therefore, the problem to be solved by the present invention is that the electroluminescence display device has a high light transmittance even when the electrode occupied area is large, and has a sufficient adhesive strength with the light emitting layer, which makes it difficult for uneven light emission to occur. An object of the present invention is to provide an electroluminescent display device using a transparent conductive laminate having a low sheet resistance.

[0007]

Means for Solving the Problems The above-mentioned problems are as follows: an organic polymer substrate, a transparent conductive layer formed on the organic polymer substrate and comprising at least one oxide of indium, tin and antimony; Thickness 2 deposited on the transparent conductive layer
The present invention provides a solution to an electroluminescence display device including a transparent conductive laminate having a metal layer of 00 Å or less.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An electroluminescent display device of the present invention comprises an organic polymer substrate and a transparent conductive layer formed on the organic polymer substrate and comprising at least one oxide of indium, tin and antimony. And a transparent conductive laminate having a metal layer having a thickness of 200 Å or less, which is deposited on the transparent conductive layer.

In particular, the electroluminescence display device of the present invention comprises a light emitting layer integrated (bonded or bonded) with the metal layer having a thickness of 200 Å or less of the transparent conductive laminate. . The material of each layer constituting the transparent conductive laminate 1 as shown in FIG. 1 in the present invention will be described below.

The material of the base 2 constituting the transparent conductive laminate 1 is made of polyimide, polyethersulfone, polysulfone, polyester such as polyethylene terephthalate, polyethylene 2,6-naphthalenedicarboxylate, polydiallyl phthalate, polycarbonate and the like. Base resin, aromatic polyamide, polyamide, polypropylene, cellulose triacetate and the like. These may of course be used alone or as a blend as a homopolymer or a copolymer. There is no particular limitation as long as it is an organic polymer compound having excellent heat resistance, but a compound having heat resistance of 80 ° C. or higher is preferable. The organic polymer substrate is preferably a flexible film.

The material of the transparent conductive layer 3 provided on the surface of the substrate 2 includes a material made of at least one oxide selected from the group consisting of indium, tin, cadmium and antimony. Typical examples are indium oxide, tin oxide, indium-tin oxide mixture, tin oxide-
Antimony mixtures. As a material of the metal layer 4 provided on the surface of the transparent conductive layer 3, indium, tin, cadmium, zinc, titanium, antimony, aluminum,
Tungsten, molybdenum, chromium, tantalum, nickel, platinum, gold, silver, copper, palladium and the like can be mentioned.

The method for producing the transparent conductive laminate 1 is as follows.
That is, the formation of the transparent conductive layer 3 is performed by a sputtering method or a reactive evaporation method using indium, tin, an indium-tin alloy, a tin-antimony alloy or the above-mentioned oxide material as an evaporation source, or a lower oxide of the above-mentioned material. The method may be performed by applying a method of oxidizing the adhered layer by at least one of heating oxidation, discharge oxidation, and solution oxidation, or a method such as spray coating. The metal layer 4 may be formed by a sputtering method or the like. A method such as a vapor deposition method may be used.

After the transparent conductive layer 3 is formed on the transparent insulating substrate 2 composed of the organic polymer compound constituted as described above, the metal layer 4 having a thickness of 200 mm or less is formed on the transparent conductive layer 3. A transparent conductive laminate 1 having
As shown in FIG. 2, a laminate 5 having a light-emitting layer in which an insulating layer 7 as an electrical protection layer and a light-emitting layer 8 are adhered on a metal electrode layer 6 is combined with the metal layer 4 and the light-emitting layer 8 as shown in FIG. Are integrated by a pressure / heating roller 9 so that the electroluminescent display device is bonded.

At this time, when the thickness of the metal layer 4 is 200 Å or less, the light transmittance is lowered by providing the metal layer 4, but the light transmittance is only slightly decreased, and the transparent conductivity is reduced. It was found that the adhesive strength between the laminate 1 and the laminate 5 is increased. Further, it has been found that when the thickness of the metal layer 4 exceeds 200 °, particularly when it exceeds 250 °, the sheet resistance is reduced, but the light transmittance and the adhesive strength tend to be significantly reduced.

When a metal is left in the atmosphere, an oxide film of several tens of degrees is formed on the surface, for example, about 20 degrees for aluminum, about 10 degrees for silver, about 50 degrees for tin, and about 40 degrees for copper. It is known that a natural oxide film is formed on the surface of the metal layer 4. Therefore, there is also a metal layer 4 according to the present invention in which a natural oxide film is formed on the surface. Therefore, it is expected that most of the metal layer 4 is in a naturally oxidized state.

After the transparent conductive layer 3 is formed on the organic polymer substrate as described above, the metal layer 4 is formed on the transparent conductive layer 3.
Can be easily patterned into a predetermined pattern by overlappingly cutting and etching the metal layer 4 and the transparent conductive layer 3 using a predetermined mask. FIG. 3 is a plan view showing an example of a patterned transparent conductive laminate, and FIG.
It is sectional drawing in the V-IV line. A transparent conductive layer 3 and a metal layer 4 deposited thereon are arranged in a predetermined pattern on the insulating transparent substrate 2, and are patterned from one end of each pixel toward the end of the transparent conductive laminate 1. Wiring 3a,
3b is extended.

In general, the characteristics of the transparent conductive laminate are as follows:
The light transmittance (light having a wavelength of 550 mμ) is 50% or more, preferably 80% or more, and the sheet resistance is 1.5 kΩ / □ or less.
It is desired that the transparent conductive laminate 1 of the present invention is preferably 1000 Ω / □ or less, and has an adhesive strength to a laminate having a light emitting layer of 200 g / 2.5 cm or more. Is pleased.

The present invention will be specifically described below with reference to examples.

[0019]

Reference Example 1 A polyethylene terephthalate (PET) film having a thickness of 75 μm was used as the substrate 2, and a mixture of indium oxide and tin oxide (ITO, the mixing ratio was 95).
500 parts by weight of a transparent conductive layer 3 having a thickness of 5 parts by weight was subjected to direct current reactive sputtering using an ITO target or an indium and tin (90 parts by weight: 10 parts by weight) alloy target (Ar gas pressure was 10 ^-3 Torr). ), On which a metal layer 4 made of tin having a thickness of 0 to 800 °
Was formed by a vapor deposition method (a degree of vacuum of 10 ⁻⁵ to 10 ⁻⁶ Torr) to form a transparent conductive laminate 1.

The sheet resistance and light transmittance of the transparent conductive laminate 1 were measured, and the results are shown in FIG. still,
The thickness of the metal layer 4 is calculated from the indicated value of the evaporation rate meter and the evaporation time. The thickness of the tin layer is 0,400 mm,
Each point of 600 ° and 800 ° is a value for the comparative transparent conductive laminate.

From the figure, it can be seen that when the thickness of the tin layer is 200 ° or less, a light transmittance of 50% or more can be obtained.
Further, it can be seen that the sheet resistance increases as the thickness of the tin layer decreases, but does not exceed 1000 Ω / □ even if the thickness is reduced. Also, the surface of the transparent conductive laminate 1 is ESC
The results are shown in FIG. According to this, the binding energy of Sn3d5 _{/ 2} is 486.4e.
From V, it can be seen that the surface of the metal layer 4 is in the state of tin oxide. This is a natural oxide film that a metal usually has, usually several tens of mm, and it is considered that the metal layer 4 in this embodiment also has a natural oxide film.

[0022]

Example 1 Aluminum plate 6 having a thickness of 0.2 mm
On top, BaTiO ₃ powder is dispersed in a resin, coated and dried to a thickness of several μm with a wire bar, and further, zinc sulfide and manganese powder are further dispersed thereon in a cellulosic resin such as cyanoethylated cellulose to form a coating liquid. After coating and drying, a laminate 5 (see FIG. 2) provided with a light emitting layer 8 having a thickness of several tens of μm was prepared. As described above, since the light emitting layer 8 is formed of the powder dispersion layer, it has an uneven surface of several tens of μm.

Then, the laminate 5 provided with the light emitting layer 8 and the transparent conductive laminate 1 of Reference Example 1 (the thickness of the tin metal layer 4 is 20 °) are combined with the metal layer 4 and the light emitting layer 8. Were combined by a heating / pressing roller 9 to form an electroluminescent display device. However, the roller pressure is 1K
g / cm, roller temperature 150 ° C, transparent conductive laminate 1
And the width dimension of the laminate 5 provided with the light emitting layer is 2.5
cm.

The sheet resistance of the transparent conductive laminate 1 is 3
30Ω / □, light transmittance was 82%. The thus obtained electroluminescent display device was measured for the adhesive strength of the above-mentioned bonded portion with a Tensilon UTM-III type 180 ° peel tester manufactured by Toyo Keiki Co., Ltd. As shown in FIG. 7, the outline of the measuring method is as follows. One end of the laminate 5 provided with the light emitting layer 8 is fixed, the transparent conductive laminate 1 is pulled in the 180 ° direction, and both are peeled off. This is a method for obtaining the relationship with the applied load, that is, the adhesive strength.

The test results are as shown by the curve a in FIG. Although the peeling load is small when the tensile distance is 1 mm or less, this is based on the play of the chuck portion (not shown) of the testing machine, and does not indicate the true load. In the figure, for comparison, the results of the same test performed on an electroluminescent display device obtained without using the tin metal layer 4 and under the same conditions except for the other conditions are also indicated by a curve b.

The electroluminescent display device using the comparative transparent conductive laminate has an adhesive strength of 70 to 12
It varies between 0 g / 2.5 cm and does not show satisfactory adhesive strength. In contrast, the electroluminescent display device of the present invention has an adhesive strength of 250 g /
It is about 2.5 cm, indicating a sufficient adhesive strength.

[0027]

Second Embodiment In the first embodiment, the transparent conductive layer 3 has a thickness of 5
The ITO is 00Å, and the metal layer 4 is indium and has a thickness of 30.
An electroluminescent display device was obtained in the same manner except that the temperature was set to 0 ° or less. Then, the sheet resistance, light transmittance, and adhesive strength of this electroluminescent display device were measured, and the results are shown in FIG.

The values in the case where the metal layer 4 is not provided are described by adding parentheses to arrows indicated by broken lines (the same applies hereinafter).

[0029]

Third Embodiment In the second embodiment, the metal layer 4 is made of tin and has a thickness of 6
An electroluminescent display device was obtained in the same manner except that the temperature was set to 00 ° or less. Then, the sheet resistance, light transmittance, and adhesive strength of the electroluminescent display device were measured, and the results are shown in FIG.

[0030]

Example 4 An electroluminescence display device was obtained in the same manner as in Example 2, except that the metal layer 4 was made of aluminum and had a thickness of 600 Å or less. Then, the sheet resistance, light transmittance, and adhesive strength of this electroluminescence display device were measured, and the results are shown in FIG.

[0031]

Fifth Embodiment In the second embodiment, the metal layer 4 is made of copper and has a thickness of 4
An electroluminescent display device was obtained in the same manner except that the temperature was set to 00 ° or less. The sheet resistance, light transmittance, and adhesive strength of the electroluminescent display device were measured, and the results are shown in FIG.

[0032]

Example 6 An electroluminescent display device was obtained in the same manner as in Example 2, except that the metal layer 4 was made of chromium and had a thickness of 500 Å or less. The metal layer 4 is formed by sputtering. Then, the sheet resistance, the light transmittance, and the adhesive strength of this electroluminescent display device were measured, and the results are shown in FIG.

[0033]

Example 7 An electroluminescent display device was obtained in the same manner as in Example 6, except that the metal layer 4 was made of palladium and had a thickness of 400 Å or less. The sheet resistance, light transmittance, and adhesive strength of this electroluminescent display device were measured, and the results are shown in FIG.

[0034]

[Embodiment 8] The same procedure as in Embodiment 3 was carried out except that the transparent conductive layer 3 was a mixture of tin oxide and antimony (antimony 2% by weight) having a thickness of 700 Å formed by the DC reactive sputtering method. I got the device.
Then, the sheet resistance, light transmittance, and adhesive strength of this electroluminescent display device were measured, and the results are shown in FIG.

[0035]

Example 9 An electroluminescent display device was obtained in the same manner as in Example 4, except that the transparent conductive layer 3 was the same as in Example 8. However, the thickness of the aluminum layer is 30
0 ° or less. Then, the sheet resistance, light transmittance, and adhesive strength of this electroluminescent display device were measured, and the results are shown in FIG.

The results of Examples 2 to 9 are summarized in Tables 1 and 2.

[0037]

[Table 1]

[0038]

[Table 2]

The following is understood from the results of these examples. (1) When the thickness of the metal layer 4 exceeds a certain value, the light transmittance decreases. However, when the thickness is 200 ° or less, a light transmittance of 50% or more can be secured. 100Å
If it is less than or equal to 75%, the light transmittance becomes 75% or more, and if the thickness of the metal layer 4 is 50 ° or less, the light transmittance becomes 80% or more. (2) Although the sheet resistance increases when the thickness of the metal layer 4 is reduced, the sheet resistance is 1000 regardless of the thickness.
Ω / □ or less. (3) The adhesive strength is such that the thickness of the metal layer 4 is 50 to 100 mm.
When the thickness of the metal layer 4 is 200 ° or less, an adhesive strength of 200 g / 2.5 cm or more is secured. Even when the thickness of the metal layer 4 is as thin as 1 to 2 mm, an adhesive strength of 200 g / 2.5 cm or more is secured. (4) From the viewpoint of adhesive strength, the thickness of the metal layer 4 is preferably 3 Å or more, more preferably 5 Å or more. From the viewpoint of light transmittance, the thickness of the metal layer 4 is 20
It is preferably 0 ° or less, preferably 100 ° or less, and more preferably 50 ° or less. Therefore, the most preferable thickness of the metal layer 4 is 5 ° to 50 °.

The reason why the adhesive strength increases as the thickness of the metal layer 4 increases, exhibits a maximum value, and tends to decrease is considered as follows. In order for the laminate 5 provided with the light emitting layer 8 and the transparent conductive laminate 1 to adhere firmly,
(A) good compatibility between the two (the wettability of both when the light emitting layer 8 is softened by roller heating);
(B) The condition that the contact area between the two is large must be satisfied.

By the way, the metal layer 4 is formed on the transparent conductive laminate 1.
When the light emitting layer 8 and the transparent conductive layer 3 are directly bonded without providing the transparent conductive layer 1, the transparent conductive laminate 1 has flexibility,
Although the uneven shape of the surface of the light emitting layer 8 and the contact area when the roller is pressed can be increased, the transparent conductive layer 3 is formed in a highly oxidized state, so that the compatibility between the light emitting layer 8 and the transparent conductive layer 3 is improved. Inferior, adhesive strength does not increase.

On the other hand, when the metal layer 4 is provided on the transparent conductive laminate 1 and the light emitting layer 8 and the transparent conductive layer 3 are bonded via the metal layer 4, the metal layer 4 is thin and thus transparent. The flexibility of the conductive laminate 1 is hardly reduced, and the light emitting layer 8
Since the unevenness of the surface and the contact area when the roller is pressed can be sufficiently ensured, and the light-emitting layer 8 has good adaptability to the metal layer 4, the adhesive strength is high.

Even if the metal layer 4 is provided on the transparent conductive laminate 1, if the metal layer 4 is too thin, the formation of the metal layer 4 is incomplete and not partially formed. The effect of the presence of the metal layer 4 is not sufficiently exhibited, or the formed metal layer 4 does not have perfect adhesion to the transparent conductive layer 3 and the metal layer 4 is easily peeled off from the transparent conductive layer 3, so that the adhesive strength is reduced. I do.

On the other hand, if the metal layer 4 is too thick, the flexibility of the transparent conductive laminate 1 is reduced, and the unevenness of the surface of the light emitting layer 8 and the contact area when the roller is pressed cannot be sufficiently ensured. Strength decreases. In addition, in addition to the above embodiment,
The results obtained when the sputtering method was used to form the metal layer 4 and the following metal was used as the material were as follows.

When cadmium or zinc is used for the metal layer material, the result is almost the same as that when tin is used for the metal layer material, and titanium, antimony, tungsten, platinum, gold, silver When molybdenum, tantalum, or nickel was used, the results were almost the same as those when chromium or palladium was used as the metal layer material. In each of the above embodiments, the metal layer is provided over the entire area of the surface of the transparent conductive layer. However, this metal layer is in a range where the adhesive force can be satisfied (for example, 50% or more of the surface of the transparent conductive layer) )
It is also possible to provide with.

The above embodiments are all examples of a transparent conductive laminate comprising only a substrate, a transparent conductive layer and a metal layer. It is also possible to provide another layer such as an ultraviolet absorbing filter layer, an antireflection film, and a water replenishing layer between the metal layer and the surface of the substrate opposite to the surface on which the transparent conductive layer is provided.

When the metal layer is made of, for example, aluminum, a thin layer of alumina is formed on the surface of the metal layer by natural oxidation.
There is almost no adverse effect on the sheet resistance, the light transmittance, and the adhesive strength, and there is no problem.

[0048]

[Effect] The transparent conductive laminate according to the present invention has features such as high light transmittance, sufficient adhesive strength with the light emitting layer, less uneven light emission, and low sheet resistance. Therefore, when used as a transparent conductive laminate for an electroluminescent display device, the brightness and contrast of the display pattern are good, the light emitting layer and the transparent conductive layer are unlikely to be separated, and the brightness unevenness does not occur. A clear image can be obtained for a long time.

[Brief description of the drawings]

FIG. 1 is a sectional view of a transparent conductive laminate.

FIG. 2 is an explanatory diagram showing adhesion between a transparent conductive laminate and a laminate provided with a light emitting layer.

FIG. 3 is a plan view of a transparent conductive laminate in which a transparent conductive layer and a metal layer are patterned.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a graph showing the relationship between the thickness of the metal layer and the sheet resistance and light transmittance.

FIG. 6 ESCA analysis data of a transparent conductive laminate having a metal layer.

FIG. 7 is an explanatory diagram illustrating a peel test.

FIG. 8 is a graph showing a relationship between a pulling distance and a peeling load in a peel test.

FIG. 9 is a graph showing the relationship between the thickness of a metal layer and sheet resistance, light transmittance and adhesive strength.

FIG. 10 is a graph showing the relationship between the thickness of a metal layer and sheet resistance, light transmittance and adhesive strength.

FIG. 11 is a graph showing the relationship between the thickness of a metal layer and sheet resistance, light transmittance, and adhesive strength.

FIG. 12 is a graph showing the relationship between the thickness of a metal layer and sheet resistance, light transmittance and adhesive strength.

FIG. 13 is a graph showing the relationship between the thickness of a metal layer and sheet resistance, light transmittance and adhesive strength.

FIG. 14 is a graph showing the relationship between the thickness of a metal layer and sheet resistance, light transmittance and adhesive strength.

FIG. 15 is a graph showing the relationship between the thickness of a metal layer and sheet resistance, light transmittance and adhesive strength.

FIG. 16 is a graph showing the relationship between the thickness of a metal layer and sheet resistance, light transmittance and adhesive strength.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent conductive laminated body 2 Substrate 3 Transparent conductive layer 4 Metal layer 5 Laminated body 8 Light emitting layer 9 Pressure / heating roller

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H01B 5/14 H01B 5/14 A

Claims (1)

[Claims] 1. An organic polymer substrate, a transparent conductive layer formed on the organic polymer substrate and containing at least one oxide of indium, tin, and antimony, and a transparent conductive layer deposited on the transparent conductive layer. An electroluminescent display device comprising a transparent conductive laminate having a metal layer having a thickness of 200 Å or less.