JPH03280394A - Thin film type electroluminescence element - Google Patents

Abstract

PURPOSE:To make an EL material which emits efficiently a blue color with good tone, by using a fluorescent substance having a complex ion light emission center to an EL layer. CONSTITUTION:As a transparent electrode 2 an ITO is formed on a glass base board 1, while a CaWO4 film is formed as a light emitting layer 3 by the RF sputter method, and thereover Y2O3 is formed as an insulative layer 4 by the electron beam evaporation method. A blue colored light emission as not achieved by any conventional technique is obtained by energizing the formed thin film type EL element with a voltage of 5kHz. This demonstrates possibility of using a fluorescent substance having complex ion light emission center as the light emitting layer even in electroluminescence of thin film type, and it is practicable to fabricate elements emitting different colors through the use of other complex ion light emission centers.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a thin film electroluminescent device (hereinafter abbreviated as a thin film EL device).

[Prior Art] Conventionally, there have been no luminescent materials, particularly blue luminescent layer materials, used in full-color EL displays.

A fluorescent material is used as the material for the light-emitting layer, and its luminescent color is almost the same as that of the phosphor.

In the field of fluorophores, their luminescence mechanisms can be classified into: (1) donor-acceptor pair (D-A pair) luminescence;
) Luminescence centered on rare earth or transition metal ions, etc., and (3) Luminescence centered on complex ions.

Conventionally, there has been no example of utilizing light emission centered on complex ions in a thin film EL string.

[Problem to be solved by the invention WrJ] The present invention aims to provide an EL light-emitting material that emits blue light with good color tone and has high luminous efficiency in order to realize a full-color EL display. .

[Means for Solving the Problems] The structure of the present invention for solving the above problems is an EL device having an insulating layer on at least one side on a light-transmitting striped electrode formed on a transparent substrate. A thin film EL device having a light emitting layer and having striped electrodes thereon perpendicular to the striped electrodes, wherein the EL light emitting layer is a thin film made of a phosphor material containing a complex ion as a light emitting center. It is element.

Among the phosphor materials having a complex ion luminescent center, CaWO4 (calcium tungstate) is the most suitable as a material that emits blue light, so we will only mention this material here, but of course other materials may also be used. Similar effects can be obtained if the emission wavelength is blue. Furthermore, similar material systems can be used for other luminescent colors as well.

The method for producing the light-emitting layer of the thin-film EL device of the present invention is not particularly limited, but since it is a multi-component compound, sputtering method, carbon
It is desirable to use the VD method.

Further, the structure of the thin film EL element is not limited in any way, and therefore, conventionally used structures and materials may be used.

Hereinafter, the present invention will be specifically explained with reference to Examples.

[Example] Here, a thin film EL element having a structure as shown in FIG. 1 was manufactured. ITO as transparent electrode 2 on glass substrate
Then, a Ca WO 4 thin film was formed as the light emitting layer 3.
It was manufactured by F sputtering method. After forming the light emitting layer, Y2O:l (yttrium oxide) was formed as the insulating layer 4 by electron beam evaporation.

FIG. 2 shows the luminance-applied voltage (LV) characteristics of the thin film EL cord thus obtained.

A voltage with a limit of 5 Kllz was applied to excite the device.

Next, FIG. 3 shows the EL spectrum. As can be seen from this spectrum, the emission color was blue.

As described above, by using Ca W 04 in the light emitting layer, blue light emission, which could not be obtained with the conventional technology, was realized. This shows that a phosphor having a complex ion luminescent center can be used in the luminescent layer even in thin film EL, and it is possible to use a phosphor having a complex ion luminescent center in the luminescent layer.
The device can be manufactured.

[Effect of the invention] As explained above, by using a phosphor having a complex ion luminescent center in the EL emitting layer, EL, which could not be realized in the past, can be achieved.
We were able to realize the characteristics, especially blue light emission.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of the structure of the thin film EL device of the present invention, and FIG. 2 is a diagram showing the luminance and applied voltage (
FIG. 3 is a graph showing the EL spectrum of the EL light emitting device of the same example. ■...Glass substrate, 2...Transparent electrode, 3...Light emitting layer, 4...Insulating layer, 5...Back electrode. Figure ζ Figure 2 Applied voltage Vrms (V)

Claims (1)

[Claims] A thin film having an electroluminescence emitting layer with an insulating layer on at least one side on a light-transmitting striped electrode formed on a transparent substrate, and having a striped electrode orthogonal to the striped electrode on top of the electroluminescent layer. 1. A thin film electroluminescent device, wherein the electroluminescent layer is a thin film made of a phosphor material containing complex ions as a luminescent center.