KR19990022666A - Electric luminescence element - Google Patents

Abstract

An object of the present invention is to provide an electroluminescent device that emits high efficiency and high luminance.

It is to add the induced light excitation component to the conventional light emitting component by providing a light excitation layer in which the light excitation layer is mixed so that the induced light is excited by receiving the light emission of the light emitting layer or the light excitation layer in which the light excitation layer is mixed.

Description

Electric luminescence element

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric luminescence device which emits light by applying an alternating current or a direct current voltage between a pair of electrodes and is used for a liquid crystal backlight or the like.

As an electric luminescence element, a thin surface light emitting element uses the reflective back electrode layer sheet which consists of metal sheets, such as aluminum, for obtaining high efficiency, and the means which reflects the light leaking from an insulation breakdown layer to the whole surface, etc. has been used. .

The electric luminescence element is used for backlights such as a handheld type LCD-equipped product, and since the driving power of the current product becomes a small power source such as a battery or a button battery, it has a low current consumption and prolongs the battery life time. There is a growing demand for relief.

On the other hand, the electroluminescent device has a low current consumption in a conventional product, so that light emission imbalance is likely to occur, making it difficult to see the LCD display.

On the contrary, in order to emit light with high luminance, it is necessary to start a high frequency high voltage and a high current, thereby shortening the lifespan.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of conventional electric luminescence elements, and its object is to provide high efficiency to achieve high brightness in the case where the current consumption is small or the same as the conventional current consumption under conventional luminance generation conditions. An object of the present invention is to provide an electroluminescent device that emits high luminance.

In order to achieve the above object, the electroluminescent device of the present invention emits light by incorporating a phosphor into an excitation layer or a light emitting layer incorporating a light excitation material such as a fluorescent pigment and a fluorescent dye to excite the induced light by receiving light from the light emitting layer. By providing a layer, high luminance emission is obtained by adding the induced light excitation component to the light emitting component of the light emitting layer.

That is, the first excitation layer made of coating such as a transparent light excitation film or printing in which the light excitation material is mixed in the light transmissive range is disposed on the front side of the light emitting layer.

In addition, a second excitation layer made of coating such as an optical excitation film or printing incorporating an optical excitation material is disposed on the rear side of the light emitting layer.

In addition, an optical excitation material is mixed in the light emitting layer and the insulating layer.

1 is a first embodiment of the present invention electroluminescent device.

2 is a second embodiment of the present invention electroluminescent device.

3 is a third embodiment of the present invention electroluminescent device.

4 is a fourth embodiment of the present invention electroluminescent device.

5 is an explanatory diagram of a conventional electric luminescence element.

6 is an explanatory diagram of spectral distribution of the electroluminescent device of the present invention.

Explanation of symbols for main parts of the drawings

1: transparent conductive film 2: light emitting layer

3: insulating layer 4: back electrode layer

6: 1st excitation layer 7: 2nd excitation layer

8: light emitting excitation layer 9: insulation insulating layer

11: reflective layer

The photo-excited material uses daylight fluorescent pigments, etc., and emits light by being qualified by irradiation of artificial light such as daylight, fluorescent lamp, mercury lamp, etc.

FIG. 6 is an explanatory diagram of spectral distribution for fluorescence color spectral distribution of a standard light source C coated on a white base cloth.

The fluorescent color (A) serving as an excitation component of the photoexcited material can be divided into a pure reflection component (C) in which the fluorescent component (B) and the fluorescent component are not mixed. Normal color (D), which consists only of reflected light of almost the same color as this light excitation substrate, absorbs a certain portion of the incident white light, emits heat energy and others other than light, and the remainder reflects the color by appearing to be colored. However, the fluorescent color (A) has an intensity that is somewhat higher than the ordinary color (D) of the residue that selectively absorbs the incident white light, and radiates again the energy of the incident light absorbed as fluorescence in addition to thermal energy.

Since the fluorescence energy is naturally smaller than the incident energy, the frequency becomes small, and as a result, the wavelength becomes long. As a result, the wavelength range of the reflection component and the wavelength range of the fluorescent component are close to each other, so that both components are combined to obtain a spectle having a high peak component that can be seen in the fluorescent color (A).

When assembled with the electroluminescence, the excitation component of an optical excitation material stronger than the reflected light is added to the fluorescent component of the electroluminescence itself, thereby making it possible to emit high luminance light from the electroluminescence element.

EXAMPLE

4 and 5 are cross-sectional explanatory diagrams of a conventional electric luminescence element.

In the electroluminescent device, the insulating layer 3 and the light emitting layer 2 are sandwiched between the transparent conductive film 1 forming the transparent conductive layer on the lower surface and the back electrode layer 4, and the transparent conductive film 1 AC or DC voltage is applied to the light emitting layer 2 through the back electrode layer 4.

The light emitting layer 2 is formed of zinc sulfide or the like as an electroluminescent material deposited on the transparent conductive layer formed on the lower surface of the transparent conductive film 1. As the transparent conductive film 1, an ITO electrode film made of indium tin oxide as a transparent conductive layer or the like is widely used.

In addition, although the transparent conductive film 1 and the back electrode layer 4 are covered with the sealing film 10 in FIG. 4, the sealing film 10 may be absent by treating the light emitting layer 2 hardly with moisture absorption. .

1 (a), (b), (c), (d) and (e) are explanatory diagrams of a first embodiment of the electroluminescence of the present invention.

In the drawings, the same symbol as that in FIG. 4 has the same name and the same function.

1 (a), (b), (c), (d), and (e) show a conventional electroluminescent element shown in FIG. 5, namely, a transparent conductive film 1, a light emitting layer 2, and an insulating layer laminated thereon. It is a 1st Example of the electroluminescent element of this invention which provided the 1st excitation layer 6 which becomes a transparent light excitation film etc. on the front surface of the light emitting layer 2 among the layer 3 and the back electrode layer 4. .

In FIG. 1 (a), the surface of the transparent conductive film 1 is coated with a transparent light excitation film or printing, which is a first excitation layer in which light excitation materials such as fluorescent pigments and fluorescent dyes are mixed in a light transmissible range. Excreted on The sealing film 10 is sealed including the first excitation layer 6 and the back electrode layer 4. Here, when a voltage is applied between the conductive film 1 and the back electrode layer 4, the light emitting layer 2 emits light. Light emission of the light emitting layer 2 is directed to the side of the insulating layer 3 on the rear side and the first excitation layer 6 on the surface side. In FIG. 1 (a), since the amount of light emission on the side of the natural layer 3 and the amount of reflection on the back surface are considered to be the same as in the related art, only light from the light emitting layer 2 directed toward the first excitation layer 6 is considered. good. In addition to the light emitting component of the light emitting layer 2, the excitation component of the light excited by the light excitation material included in the first excitation layer 6 is emitted toward the front in the sealing film 10, thereby resulting in high luminance light emission.

In addition, the fluorescent color (A) by the light excitation material remains for a short time after the light of the light emitting layer 2 is burned out, and the light intensity nonuniformity which is likely to occur when the low resolution is reduced due to the internal reflection effect is also achieved. Play the role of resolving.

FIG. 1 (b) shows the same action of the first excitation layer 6 as the sealing film 10 is removed from the electric luminescence device shown in FIG. 1 (a).

In addition, in FIG.1 (c), the 1st excitation layer 6 was adhere | attached on the sealing film 10 surface of the conventional electroluminescent element shown in FIG. 5, The light of the light emitting layer 2 was a sealing film. As an extinction by (10), since the film 10 is extremely thin, the effect | action of the 1st excitation layer similar to FIG. 1 (a) arises.

1 (d) and (e) show a first excitation layer 6 serving as a transparent light excitation film or a transparent coating material incorporating an excitation material between the light emitting layer 2 and the transparent conductive film 1. As provided, as compared with FIG. 1 (a), since the first excitation layer is closer to the light emitting layer 2, the loss in the way is also reduced, and thus the brightness can be expected more.

2 (a), 2 (b) and 2 (c) show a conventional electroluminescent element shown in FIG. 5, namely, a transparent conductive film 1, a light emitting layer 2, an insulating layer 3, and a back electrode layer (laminated) 4) A second embodiment of the electroluminescent device of the present invention in which a second excitation layer 7 made of a coating such as light excitation film or printing is disposed on the rear surface of the light emitting layer 2.

In FIG. 2 (a), the back electrode layer 4 in which coating such as an optical excitation film or printing, which is used as the second excitation material 7 incorporating optical excitation materials such as fluorescent pigments and fluorescent dyes, is used as an aluminum laminate sheet or the like 4 Excluded behind).

The sealing film 10 is sealed including the transparent conductive film 1 and the second excitation layer 7. Here, when a voltage is applied between the conductive film 1 and the back electrode layer 4, the light emitting layer 2 emits light. Light emission of the light emitting layer 2 is directed to the transparent conductive film 1 on the front side and the back electrode layer 4 on the back side. In Fig. 2 (a), it is considered that the components reflected from the surface of the back electrode layer 4 in the direction of light emission toward the transparent conductive film 1 and in the opposite direction are the same as in the conventional example shown in Fig. 5.

However, the back electrode layer 4 is made of a thin aluminum laminate sheet or the like, or is molded by printing of a conductive material or the like, so that when viewed in detail, it is in a porous state and leaks light emitted from the light emitting layer 2. This leakage component enters the second excitation layer 7 and light is excited by the light excitation material. A part of this excited light is returned to the back electrode layer 4 and the light emitting layer 2 and directed toward the transparent conductive film 1.

Such a return makes it possible to achieve higher luminance than the conventional example shown in FIG.

FIG. 2 (b) shows the sealing film 10 removed from the electroluminescent element shown in FIG. 2 (a), and the action of the second excitation layer 7 is the same. In addition, in FIG.2 (c), titanium oxide etc. are disperse | distributed and apply | coated to the back surface of the electroluminescent element shown in FIG.2 (b). Alternatively, the reflective layer 11 formed of the laminate sheet is provided, and the light excited by the second excitation layer 7 is returned to the transparent conductive film 1 and is transmitted without being omitted. It is possible to achieve high luminance light emission further than the example of 2 (b).

3 (a) and 3 (b) show a third embodiment of the electroluminescent device of the present invention in which a light excitation material is incorporated into the light emitting layer 2 to form a light emission excitation layer 8. FIG. The sealing film 10 is sealed including the transparent conductive film 1 and the back electrode layer 4.

Incorporating the light excitation material into the light emitting layer 2 can emit high luminance by emitting light of the light emission component of the light emitting layer 2 itself and the excitation component of the light excitation material.

3 (c) and 3 (d) show an electroluminescence in which an optical excitation material is mixed into the insulating layer 3 provided between the light emitting layer 2 and the back electrode layer 4 to form the insulating excitation layer 9. It is an example of a necessity element, and FIG. 3 (a) is sealed by the sealing film 10. As shown in FIG.

4 (a), (b), (c), and (d) illustrate the present invention's electroluminescent device using two excitation layers, a second excitation layer 7 and an insulation excitation layer 9. 4 shows the assembling method of the second excitation layer 7 and the insulation excitation layer 9.

In addition, the same high luminance light emission can be achieved even when assembling two or more excitation layer portions.

On the contrary, if the conventional brightness is good, the current and the like are reduced to reduce the amount of light emitted from the light emitting layer 2. The light emission nonuniformity generated in this case is averaged by the afterglow action of the light excitation materials and the reflected light components of the light excitation materials, thereby enabling uniform surface light emission.

In the electroluminescent device of the present invention, as described above, the first excitation layer 6 and the second excitation layer 7 incorporating the light excitation material are disposed so as to be sandwiched by the respective portions of the electroluminescence element or the light emitting layer. (2) By incorporating an optical excitation material into the main constituent layers of the electroluminescent element such as the insulating layer 3 and the back electrode layer 4, there is an effect of enabling high-brightness light emission of the prior art.

In addition, since the high luminance light emission is independent regardless of the voltage and current applied between the transparent conductive film 1 and the back electrode layer 4, the amount of power required for the unit light emission amount can be reduced to increase the light emission efficiency.

In addition, the light excitation material has an afterglow effect, and the light emission is averaged by the reflection of the light excitation materials, thereby enabling uniform surface light emission. For this reason, it is impossible to lower the current below a certain level in order to generate a conventional light emission nonuniformity, but the light excitation allows visually uniform light emission, so that a slightly dark surface light emission following low tracking is realized. There is an effect that the life of the battery and the battery serving as a power source can be realized by long life and low consumption.

Claims (3)

In the electroluminescent layer in which a transparent conductive film, a light emitting layer, an insulating layer, and a back electrode layer are laminated, a transparent light excitation film or a coating such as a printing incorporating light excitation materials such as fluorescent pigments and fluorescent dyes in a light-transmitting range. The first excitation layer is disposed on the front side of the light emitting layer, and the amount of light emitted from the light emitting layer is further excited by the first excitation layer to emit high luminance. In an electroluminescent layer in which a transparent conductive film, a light emitting layer, an insulating layer, and a back electrode layer are laminated, a second excitation layer serving as a coating such as a photoexcitation film or printing incorporating light excitation materials such as fluorescent pigments and fluorescent paints. The light emitting layer is disposed on the rear side of the light emitting layer, and the light emitting element emits light while emitting the light emitted from the light emitting layer. In the electroluminescence by laminating a transparent conductive film, a light emitting layer, an insulating layer, and a back electrode layer, light excitation materials such as fluorescent pigments and fluorescent paints are mixed into the light emitting layer and the insulating layer, and the light excitation layer and the insulation excitation layer are used. And an optical luminescence device having a light excitation function in the light emitting layer and the insulating layer so as to emit light having a luminance corresponding to the amount of excitation light emission.