JPS60170195A - El display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a multicolor display type EL display device.

BACKGROUND TECHNOLOGY AND PROBLEMS Conventionally, two methods have been used to increase the number of colors in a distributed AC EL display device.
There are different types. There are two methods: using color filters and using phosphors that emit light in each color.

However, when a color filter is used, there is a problem in that the brightness becomes low. Also, for example, green ZnS:Cu,
At (Cu and At are activators), blue Zn:Cu, I,
When using phosphors such as orange ZnS:Cu, Mn, etc., there is a problem in that the luminance reduction due to one use is greatly different because the luminance attenuation characteristics of each phosphor are different.

OBJECTS OF THE INVENTION In view of the above-mentioned points, the present invention provides a multi-color display type BL display device that has high brightness and does not exhibit any difference in brightness reduction for each color even after long-term use. be.

Summary of the Invention The present invention is an EL display device in which the same phosphor and a mixture of the same phosphor and a dye of a desired color are used as the luminescent material in the luminescent layer, and the display surface is divided into a plurality of colors. .

According to the above invention, each color has stable luminance characteristics.
A display device can be obtained.

Example In this EL display device, the luminescent material in the luminescent layer is a phosphor that emits blue-green light such as ZnS:Cu, CL, and this phosphor and a red dye Rhodamine B (C28H).
3103N2C4, orange dye rhodamine 5 (C2oH2
3N20!1C2), yellow dye Verdrazine (C,6H
9N4Nh s 09 S 2 ).

Other phosphors that emit blue-green light include ZnS:Cu
, I can be used. Furthermore, for high voltage applications, ZnS:Cu, Br, which emits green light, may be used. Then, using these four types of light emitting materials, the light emitting layer of the display portion having a desired shape is formed so as to be color coded. You can color code from 2 to 4 colors as needed.

When a light-emitting layer is formed using the light-emitting material according to the present invention, it not only exhibits a unique color when fluorescent, but also exhibits a unique color when exposed to natural light when not emitted. The colors of these luminescent materials and the colors when they emit light are as follows.

Luminescent material Color of the material itself Color when emitting light ZnS: CmaCt Yellowish milky white Blue-green Zn
S: Cu, CL + o-damin B Reddish purple Purple ZnS: Cu, CL + o-damin S Light brownish white Color ZnS: CuXCL + Pardrazine Brass green Green For the above luminescent materials, the wavelength and relative energy at the time of light emission in order from the top The results of measuring the relationship between the two are shown in FIGS. Further, the results of measuring the reflective female vectors of the four types of luminescent materials mentioned above are shown in FIG. Figure 7
Curve A is ZnS:Cu1CL, curve B is znS:C
u1Ct and rhodamine B1 curve C is Zn8:Cu, C1
and Roguemi yS, the curve is ZnS: Cu, CL and/
This is Drazin.

Therefore, in the display device according to the present invention, there is no need to keep the light-emitting layer emitting light at all times as in the conventional case, and when it is bright, the display portion appears to be color-coded depending on the color of the light-emitting material itself, so there is no need to supply power when it is bright. become.

Next, an embodiment of the present EL display device and its manufacturing method will be described.

FIG. 1 is a sectional view of a flexible EL display device (1). This EL display device (1) is constructed by, for example, sealing a substantially square thin plate-like EL element (2) with two upper and lower transparent moisture-proof films (3), and the entire structure is flexible. ing. The EL element (2) consists of a transparent polyester film (4), on which a layer of ITO is vacuum-deposited.
It consists of a transparent electrode (5), a light emitting layer (6), and a back electrode (7) made of Ar foil.

The surface of this light emitting layer (6) becomes a display surface. For example, when displaying the numbers 1, 2, and 3 as shown in Fig. 2, the luminescent layer (9) of the part 1 contains a luminescent material containing a mixture of ZnS:Cu, CL and rhodamine B, and the luminescent layer (9) of the part 2 contains a luminescent material containing a mixture of ZnS:Cu, CL and rhodamine B. The light-emitting layer a1 contains a light-emitting material containing ZnS:Cu, a mixture of CL and padrazine, and the light-emitting layer (11) in the portion 3 contains ZnS:C.
A luminescent material containing only CL is used, and a luminescent material containing a mixture of Zn:Cu, CL and rhodamine S is used for the luminescent layer (2) in other parts. Specifically, ZnS:C
u, CL (50-95 wt 11%) and dye (0,01
~0.1% by weight) mixture with a high dielectric constant binder (~0.1% by weight)
The luminescent material is constituted by dispersing it in a liquid (by weight).

ZnS: Cu, the content of Cu and Ct in CL is
They are 0.045 weight factor and 0020 weight factor, respectively.

As the high dielectric constant binder, trifluoroethylene-polyvinylidene fluoride, cyanoethyl cellulose, etc. can be used. This light emitting layer (6) has a transparent electrode (5)
The material for the light emitting layer (6) in slurry form is coated on top of the light emitting layer (6) by screen printing to a thickness of 50 μm, and then dried at 150° C. for 30 minutes.

Note that the light emitting layer (6) may contain an appropriate amount of dimethylacetamide as a solvent for adjusting viscosity.

Although the light-emitting layer (6) can be formed using a slurry material in which a phosphor and a dye are mixed, another method is to apply a phosphor. After that, a layer may be formed by printing a dye dispersed in the inder on this layer.The Ar foil that will become the back electrode (7) is a 100 μm thick Ar foil on the light emitting layer (6). The EL element (
The EL element (2) is sealed by thermocompression bonding two upper and lower moisture-proof films (3) to the BL device t (1).
). This gL element (2) is sealed using dry Ar
Alternatively, since N2 is carried out in a gas atmosphere, the gap (8) in the EL device (1) is filled with dry Ar or N2 gas. As the moisture-proof film (3), a fluorohalocarbon film (for example, Aclar (trade name) manufactured by Allied Chemical Company, USA), a polychlorotrichloroethylene film, or the like is used. The electrodes (5) and (7) are provided with lead terminals (not shown), and the leads (not shown) are connected to two moisture-proof films (3) for connection to an external power source.
It is derived to the outside from between.

An alternating current voltage is applied to the electrodes (5) and (7) of this EL device (1) via leads to cause the light emitting layer (6) to emit light. Each light-emitting layer had the light-emitting material as described above.The part of the reef 1 was purple, the part 2 was green, the part 3 was a curved green,
Other parts emit white light. However, in this EL display device, it is only necessary to apply a voltage to cause the light-emitting layer to emit light when it is dark, and when it is bright, the display of each of 1.2.3 is recognized by the coloring of the light-emitting layer itself. can do.

Effects of the Invention According to the present EL display device, since the same phosphor is used as the luminescent material in the luminescent layer, variations in the luminance of each color are eliminated, and the luminance attenuation characteristics as the luminescence time elapses. There will be no difference. Furthermore, in this display device, since each display part is colored when it is bright, the displayed content can be recognized without emitting light, and it is only necessary to make the light emitting layer emit light when it is dark. Therefore, compared to conventional EL display devices, less power is required and the life of the display device itself is extended.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the present invention, FIG. 2 is a plan view thereof, and FIGS. 3 to 6 show wavelengths and relative energies of four types of luminescent materials according to the present invention when emitting light. FIG. 7 is a characteristic diagram in which the reflection spectra of four types of luminescent materials were measured. (1) is an EL display device, and (6) is a light emitting layer. □'&"i・y2Pa Figure 1 Figure 2 [-" Figure 3 Kuku 4 Figure 11i-(A, 1 Figure 5 Figure 6 Figure 7 Meng length (nm)

Claims (1)

[Claims] An EL display device in which the same phosphor and a mixture of the same phosphor and a dye of a desired color are used as the luminescent material in the luminescent layer, and the display surface is divided into a plurality of colors.