JPS618896A - Electric field light emitting lamp - 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 The invention in the field of "Industry" relates to an electroluminescent lamp, and more particularly to a luminescent layer that emits light upon application of an alternating electric field.

Organic electroluminescent lamps, which are prized for displaying characters and figures, and as light sources for liquid crystal displays, are generally produced by the Japanese Patent Publication Publication No. 36-8.
As disclosed in Japanese Patent Publication No. 479 and Japanese Patent Publication No. 40-8575, a white high-permittivity dielectric powder such as barium titanate powder is used for a back electrode such as aluminum, a high-permittivity dielectric material such as cyanoethyl elrose, etc. A reflective insulating layer made of a mixture of 1. T, 0. It is constructed by thermo-compression sealing an electroluminescent lamp element consisting of a transparent electrode and a laminate of a transparent resin film with a resin outer film. When an AC voltage is applied between the back electrode and the transparent electrode, the phosphor particles in the light emitting layer are excited by the AC electric field and emit light.

The luminance, efficiency, and lifespan of such an electroluminescent lamp are greatly influenced by external conditions such as the magnitude and frequency of the voltage applied between the two electrodes, as well as especially by the internal conditions of the light emitting layer.

In other words, if the particle size of the phosphor particles in the light-emitting layer is made larger, the life will be extended, but the leakage current will increase and the efficiency determined by the brightness per unit power will decrease, and the unevenness of the light-emitting layer will become larger, causing luminescence spots. On the contrary, if the particle size of the phosphor particles in the light-emitting layer is made small, leakage current will be reduced, efficiency will increase, and luminescence spots will be reduced, but small-sized phosphor particles will deteriorate quickly due to moisture adsorption. It is known that the lifespan is short.

Therefore, in general electroluminescent lamps, the phosphor particles in the light emitting layer are made of particles with a normal distribution of various particle sizes, that is, they are not classified based on particle size.
Both the efficiency and efficiency were unsatisfactory.

1.The demand for electroluminescent lamps has been increasing rapidly in many directions.
There is a growing demand for products with improved longevity and efficiency. However, as mentioned above, products with long lifespans have poor efficiency, and increasing efficiency has a contradictory relationship with shortening lifespans. Therefore, products that are unsatisfactory in both lifespan and efficiency are used, and cannot fully meet the above requirements. The current situation was that I couldn't do it.

The present invention has been made in view of the increasing demand for electroluminescent lamps and the need for a lamp with good longevity and efficiency.The technical means of the present invention to meet this demand is an electroluminescent lamp. The light-emitting layer is formed by mixing large-sized phosphor particles and small-sized pigment particles into a dielectric material.

According to the above technical means, since the phosphor particles contained in the light emitting layer have a large particle size, moisture deterioration of the phosphor particles is slow, and therefore the life of the electroluminescent lamp is extended. In addition, the small-sized pigment particles contained in the light-emitting layer exert the effect of suppressing multiple currents,
Improving the efficiency of electroluminescent lamps. Furthermore, small-sized pigment particles coexist between large-sized phosphor particles, causing unevenness in the luminescent layer.
This makes the light-emitting layer smaller.

∎ Medical The present invention will be explained based on an embodiment of FIG. 1. In FIG. 1, (1> is a back electrode, (2) is a reflective insulating layer, (
3) is a light emitting layer that is a feature of the present invention, (4) is a transparent electrode,
(5) is a transparent resin film that becomes the base material of the transparent electrode (4), and an electroluminescent lamp element is formed by laminating the above (1) to (5), and this electroluminescent lamp element is directly or The resin outer films (6) (G) are sandwiched through a moisture-absorbing film such as nylon 6, and the resin outer films (6) (6) protruding from the periphery of the electroluminescent lamp element are sealed together by thermocompression. 1. An electroluminescent lamp (7) is formed. The light-emitting layer (3) is made of an organic dielectric material (8) such as cyanoethyl cellulose, and phosphor particles (9) arranged into large particle sizes by classification;
Pigment particles (
10) in a desired weight ratio.

The phosphor particles (9) are normally distributed phosphor particles represented by the chemical formula ZnS:Cu, which are classified to have a uniform particle size of 30 μm or more. In addition, the pigment particles (10) are Paythic Red-1 (chemical substance N0 (5) -1947),
Or Solvent Yellow-44 (Chemical No. (5)
General pigments having a particle size of 3 μm or less, such as 3050), are used. These phosphor particles (9) and pigment particles (10)
The mixing weight ratio of the pigment particles (10) to about 10 to 100 of the phosphor particles (9) gives excellent results in terms of characteristics.

Next, examples of various experimental results clarifying the characteristic improvement ifM9h effect of the present invention will be explained with reference to FIGS. 2 to 5. still,
(A) of the graphs in FIGS. 2 to 4 is a product of the present invention in which pigment particles of 3 μm or less are mixed in large diameter phosphor particles of 30 μm or more in an amount of 3 wt% of the weight of the phosphor ( B) is the first conventional product without pigment in which the phosphor particles in the light-emitting layer have a large particle size of 30μ11 or more, and (C) has a normal distribution in the phosphor particles in the light-emitting layer, that is, the particle size is not classified. (D) represents a general second conventional product using various materials, and (D) represents a third conventional product for comparison with the present invention, in which 3 wt % of a pigment of 3μ or less is mixed in the luminescent layer of the second conventional product. Note that this experiment was conducted at an ambient temperature of 5
These are the results obtained by applying a voltage at a frequency of 400 Hz under conditions of 0° C. and 90% humidity.

No. 215 is the result of a life test in which the lamps were turned on with the same initial brightness to prevent the brightness from decreasing. However, in order to make the initial brightness the same, for graphs (A) and (B), the applied voltage is 140μ,
For graphs (C) and (D), the applied voltage was 130 .mu.m. Generally, when lighting the same electroluminescent lamp, it is known that the brightness deteriorates more as the applied voltage increases, but as is clear from this Figure 2, graphs C and D
The brightness of the second and third conventional products decreases by half after about 200 hours, whereas the graph (A) using large-diameter phosphor particles
In the product of the present invention (B) and the first conventional product, it took about 200 hours for the luminance to be reduced by half, even though the applied voltage was increased.

This shows that the product of the present invention has a long life almost as long as the first conventional product.

Figure 3 is a graph showing the results of examining the brightness-power consumption characteristics. Figure 3 shows that when a pigment is mixed into the light-emitting layer, the power consumption required to turn on the light at the same brightness is lower than when no pigment is mixed. It can be seen that efficiency increases.

Figure 4 is a graph showing the results of examining the voltage-current density characteristics. From this figure, it can be seen that when the same voltage is applied, the current flowing in the case with pigment is less than that without pigment.
This also proves the efficiency improvement effect of the product of the present invention.

Figure 5 shows the product of the present invention and graph I in each of the above experiments.
This is the result of investigating the luminance deviation of the first conventional product of FCB).
The measurement was carried out by moving the light receiving element left and right at 11 intervals and measuring the brightness at each point with the reference position (0 point).

Graph A′ in FIG. 5 shows the luminance deviation of the product of the present invention, and graph B′ shows the luminance deviation of the first conventional product.
It can be seen that the luminance deviation is reduced to about % compared to conventional products, making lighting possible with fewer light-emitting layers.

According to the present invention, it is possible to provide a long-life, high-efficiency electroluminescent lamp that eliminates the disadvantage of low efficiency of conventional long-life electroluminescent lamps that use large-diameter phosphor particles in the light-emitting layer. .

[Brief explanation of drawings]

FIG. 1 is a partial sectional view including a partially enlarged sectional view of an embodiment of the present invention, and FIGS. 2 to 5 are characteristic diagrams showing experimental results of the product of the present invention and the conventional product. (3)--Light emitting layer, (8)-Dielectric layer, (9)°-
*m! (7)! &31m+, (10ゝ°-/J-4!
(MIN f particle.

Claims (1)

[Claims] (1) An electroluminescent lamp characterized in that a light-emitting layer is formed by mixing large-sized phosphor particles and small-sized pigment particles into a dielectric material.