JPS59175593A - Electroluminescent 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 Field of Industrial Application The present invention relates to a flat panel display device, and particularly describes the structure of a conventional light emitting device and its problems.
Both sides of the light emitter layer are sandwiched between insulator layers, and the outside 1f]
1175- et al., a double insulating layer type in which a transparent electrode made entirely of indium oxide or tin oxide is sandwiched between metal electrodes such as aluminum, and a vCEL emitter on a transparent electrode made mainly of indium oxide or tin oxide. There is a single insulating layer type in which a stimulant layer is formed, on which an insulating layer is sequentially provided, and a metal electrode is provided. In these two types of devices, when the insulator layer and the luminescent layer are formed with the same thickness and emit light by applying a sine wave or AC pulse voltage, - a heavy insulating layer Compared to the double insulating layer type, the type has a lower luminescence threshold and lower luminance, but it also has the problem of lower luminance.

OBJECTS OF THE INVENTION It is an object of the invention to provide an EL display device with high brightness and a low emission threshold voltage, which can be driven with an AC pulse voltage or a DC pulse voltage.

Constituent of the Invention: An EL light emitting layer whose main component is lead sulfide, a luminescent active substance.On one side, a semiconductor layer of a group consisting of zinc oxide, lead selenide, and cadmium sulfide is entirely formed. , an insulator layer is formed on the other surface, and means is provided for applying an AC pulse voltage and, if grown, a DC pulse voltage to the ELL light layer through the semiconductor layer and the insulator layer.
- I was able to achieve the objective described in (h). By providing a means for applying a hard pulse voltage such that the insulating layer side is positive with respect to the semiconductor layer side when the full DC pulse voltage is applied, higher brightness EL can be achieved than in the case of opposite polarity.
The purpose was to form an L display device.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 shows an example of the structure of the display section of the ELL display device of the present invention.

In the figure, 1 is a glass substrate, Corning 706
9 glass was used. A transparent electrode 2 made of tin-doped indium oxide and having a thickness of 0.1 μm was entirely formed thereon by a high-frequency sputter link method. A semiconductor layer 3 made of lead oxide and having a thickness of 600 onogstroms was entirely formed thereon by high frequency sputtering. At this time, set the substrate temperature to 1
50'C, 2x1o Tor as suha sota gas
I used the red color of r. On the semiconductor layer 3, lead sulfide and manganese as an active substance were simultaneously deposited to form a lead sulfide EL phosphor layer 4 having a thickness of 0.5 μm and containing 0.8 atoms of manganese. At this time, the substrate temperature was maintained at 220'G, and the deposition was performed at a deposition rate of 0.1 μm per minute. Then 5 in vacuum
Heat treatment was performed at 60'C for 2 hours. Next, the substrate temperature is 80
The entire insulating layer 6 having a thickness of Q4 μm17) was formed by electronic beat evaporation of yttrium oxide on the phosphor layer 4 at .degree. Finally, aluminum was deposited in full vacuum to form six reflected charges.

The transparent electrode 2 and reflective electrode 6 of the display section exploded like this.
FIG. 3 shows the light emission characteristics when an AC pulse voltage having a waveform as shown in FIG. 2(a) is applied during this period. The line in the figure (a
) indicates the luminance of the display device in this example, and (
b) shows the characteristics of the device in which only the semiconductor layer 3 was not formed in this example;
2 μm thick yttrium oxide, 0.5 μm thick Manogaf activated zinc sulfide EL phosphor layer, and 0.2 μm thick
This figure shows the characteristics of a conventional display device with a double insulating layer structure, in which an inotorium film with a thickness of As can be seen from Fig. 3, the device of the present invention allows only the drive voltage to be completely lowered without reducing the luminance of the light emitted, making it possible to reduce the voltage of the drive circuit. be.

FIG. 4 shows the display device in this embodiment when a DC pulse (FIG. 2b) with a pulse width of 20 microseconds and a frequency of 100 Hz is applied so that the reflective electrode 6 becomes positive. Shows luminescent properties. As can be seen from the figure, the display device of the present invention has a DC pulse voltage of duty 115CO.
It was possible to display with a brightness of 90 nits. The reason for this is that 1li
Electrons can be easily injected into the FF-ready-lead luminescent layer.
It is thought that this is because of 1-,6.

In the non-example, a case was explained in which zinc oxide was used as the semiconductor layer, but similar effects were obtained even when zinc heptatonide or cadmium sulfide was used.

These semiconductor layers were effective when the thickness was 300 angstroms or more. Although it is effective even if the thickness is 1 μm or more, it is not practical because it requires a long time to manufacture and is likely to be exposed.

Furthermore, as a result of research on stability and low voltage, it was found that dielectric layers such as stronotium titanate, barium titanate, lead acid/acid, lead niobate, and tankle oxide with a thickness of 0.2 to 3 μm were used as the insulator layer. By using a thin film with high dielectric strength and dielectric strength, KL can be driven at low voltage with excellent stability.
It turns out that it can be used to form display devices.

Effects of the Invention As explained above, the EL display device of the present invention has high luminance, is easy to see, and has a low driving voltage, so the withstand voltage of the integrated circuit (I # Can be fully formed. It is also possible to drive with small DC pulses,
The drive circuit can be configured simply.

Its practical value is great.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of the structure of the display section of the EL display device of the present invention, and FIG. 2 shows the applied voltage waveform. FIG. 3 shows voltage-luminance characteristics of the EL display device according to the present invention and the conventional EL display device. FIG. 4 shows the voltage-luminance characteristics of the display device of the present invention when a DC pulse voltage is applied. 1...Crow board, 2...Transparent city pole, 3...
.../Semiconductor layer, 4... EL light emitting layer, 5...
- Insulator layer, 6...Reflecting electrode. Name of agent Patent attorney Toshio Nakao 1.1 or 1 person Figure 1 Figure 2 Time Figure 3 Figure 4 (Ko)

Claims (1)

[Claims] (1) KL whose main component is zinc sulfide containing a luminescent active substance
a light emitting layer, a semiconductor layer provided on one surface of the EL light emitting layer, the semiconductor layer containing at least one selected from the group consisting of zinc oxide, zinc selenide, and cadmium sulfide as a main component; An insulator layer provided on the other surface of the phosphor layer, an AC pulse voltage applied to the EL phosphor layer via the semiconductor layer and the insulator layer, and e) a luminescent active substance of Mn, Cu, Ag. , Al,
Tb. Dy, Er, Pr, Sm, Ho,
(3) The thickness of the semiconductor layer is 300 angstroms or more. (4) The semiconductor layer, the EL light emitter layer, the insulator layer, and the electrode have transparent electrodes in this order. Laminated part on the substrate)
An insulator layer, a KL light emitter layer, a semiconductor layer, and an electrode are sequentially laminated on a transparent substrate having a transparent electrode (6) The polarity of the DC pulse voltage applied to the F and L light emitter layers On the other hand, the insulator layer side is positive.