JPS60232695A - Thin film el panel - 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 Conventionally, for AC-operated thin-film KL elements, a dagger-high electric field (about 1O°V/m) is applied to the light-emitting layer to improve dielectric strength, luminous efficiency, and operation stability. etc., 0.1
~1. Owt% Mn (or (!u, A4゜Br
A three-layer structure in which a semiconductor light-emitting layer such as ZnS, ZnSe, etc. doped with
nSe:Mn) EL devices have been developed, and improvements in luminescent characteristics have been confirmed. This thin film EL element is several KH2
It emits high-intensity light when applied with alternating current, and has a long lifespan.

As an example of a thin film EL element, ZnS:Mn thin film EL
The basic structure of the device is shown in FIG.

The structure of the thin film EL element will be specifically explained based on FIG. 5. In, O=, and SnO are formed on the glass substrate 1.

A transparent electrode 2 such as Y, 03, Ta is further layered on top of the transparent electrode 2.
, O,1,, A4. O,,S is Nu,Sin
A first dielectric layer 8 consisting of . A ZnS light emitting layer 4 is formed on the first dielectric layer 3, which is obtained by electron beam evaporation of a ZnS:Mn sintered pellet. At this time, for ZnS:Mn sintering for vapor deposition, Bererite is used, in which Mn, which is an active substance, is set at a concentration depending on the purpose. ZnS light emitting layer 4
A second dielectric layer 5 made of the same material as the first dielectric layer 8 is laminated on top of the second dielectric layer 8, and a back electrode 6 made of At or the like is further deposited thereon. Transparent electrode 2 and back electrode 6
As shown in FIG. 6, a square electrode structure is adopted in which a plurality of electrodes are formed into a strip shape and arranged perpendicularly to each other, and the transparent electrode 2 and the back electrode 6 are formed in a plan view. The crossing position 7 (shaded area) corresponds to one pixel on the panel.

The transparent electrode 2 and the back electrode 6 are each connected to an AC power source 10 via a switch 8.9.

In the above configuration, when the switches 8 and 9 are closed, the electrodes 2 and
When an AC voltage is applied between 6 and 6, the above AC voltage will be induced between dielectric layers 3 and 5 on both sides of the Zr+S light emitting layer 40, and therefore the electric field generated within the ZnS light emitting layer 4 will cause the conductor to The excited and accelerated electrons that have obtained sufficient energy directly excite the Mn luminescent center, and when the excited Mn luminescent center returns to the ground state, it emits orange-yellow light. That is, M
When the electron of n atom is excited and falls to the ground state, approximately 58
It emits strong light in a wide wavelength range with a peak of 50A.

The thin film EL device having the above-mentioned boiled structure can be used as a flat thin display device that takes advantage of the Soubène factor to display characters, symbols, still images, etc.
It can be used as a means of displaying moving images, etc., and is very effective.

However, the dielectric layer of the thin-film EL element contains many pinholes and micro-crystals generated during the manufacturing process, and moisture, etc. enters the ZNS light-emitting layer 4 through these defects, resulting in heat generation due to EL emission loss, This may lead to delamination, deterioration of device characteristics, etc.

In order to solve the above problem, as shown in Fig. 7, we have developed a method to prevent the expansion of minute thermal damage areas caused by breakdowns caused by pinholes and other imperfections peculiar to thin-film KL elements when energized. Thin WK TJ springs are known that are fixed and effective for wet photography protection in atmospheric environments, heat dissipation effects, and against vibration and deflection.

This thin-reflection KL spring/L'll will be explained based on FIG. 7. 1 is a glass substrate shown in FIG. A first dielectric layer 31 and a light emitting layer 4 are formed thereon. Second
Dielectric layer 5. A thin film KL element 12 is constructed in which a back electrode 6 is laminated. A dish-shaped rear glass plate 13 is superimposed on the glass substrate 1 to accommodate the thin film EL element 12, and the thin film EL element 12 is built into the internal gap thereof.

The joint between the glass substrate 1 and the rear glass plate 13 is sealed with a photocurable resin (photobond) ridge adhesive 14.

That is, the glass substrate 1 and the rear glass plate 18 constitute an envelope 15 for the thin film EL resistor 12. and envelope 15
Inside, the thin film E and L elements 12 are built in, and an insulating protective fluid 16 for protecting the thin film KL element 12 such as silicone oil or vacuum grease is filled and sealed. The conditions required for the insulating protective fluid 16 include permeability into pinholes, high dielectric strength, excellent heat resistance and moisture resistance, no reaction with the constituent films of the thin film KL element 12, and a vapor pressure of ≠ Isoji Temple →
It is desirable that the material be a fluid substance with a small coefficient of thermal expansion, but it is particularly required that it has permeability into pinholes, has a somewhat high dielectric strength voltage, and does not react with the films constituting the thin-film EL element.

This insulating protective fluid 16 is injected through an injection hole 17 provided in the rear glass plate 13, and this injection hole 17 is sealed with a resin 18 (Japanese Patent Laid-Open No. 12290/1983). Further, one end of the lead terminal portions of the transparent electrode 2 and the back electrode 6 of the thin film KL element 12 extends onto the glass substrate 1 outside the envelope 15 via the joint between the glass substrate 1 and the back glass plate 18. and is electrically connected to a drive control circuit (not shown).

In addition, the injection hole 17 for the protective fluid 16 is filled with the resin 1 as described above.
8, it has also been proposed to seal the glass plate 19 by bonding it with an adhesive 20, as shown in FIG.

As mentioned above, the thin film FIL spring Jv11 containing the protective fluid 16 in the envelope 15 can completely prevent moisture from entering into the atmosphere, so it is an excellent product that dramatically improves the reliability and lifespan of thin film EL panels. have an effect.

However, even in the above configuration, since the protective fluid 16 itself contains moisture, this moisture is transferred to the thin film KL element 1.
However, there still remains the problem that it invades the 2nd layer and becomes a factor of deterioration of the device characteristics. Water contained in the protective fluid 16 is removed from the envelope 1.
It is technically difficult to completely remove the water from the protective fluid 16 before injection, and even after degassing, some moisture remains in the protective fluid 16.
remain inside.

In order to deal with such problems, as shown in FIG. 9, a protective fluid 16 is contained in the envelope 15, and
A protective fluid containing fine powder of a moisture absorber such as silica gel is placed in the thin film EL panel 21 (Japanese Patent Laid-Open Publication No. 124182/1982) containing a moisture absorber 22 such as Noryl gel, and in the envelope 15. A thin film EL panel has been proposed (Japanese Unexamined Patent Publication No. 56-92581).

However, as shown in FIGS. 7 to 9, the envelope 15
When the insulating protective fluid 16 is filled and sealed inside the envelope 15, the protective fluid 16 is sealed inside the envelope 15, so that it may not be affected by a rise in ambient temperature, a thermal cycle test, or a temperature rise in the spring A during operation. When the protective fluid 16 thermally expands, the pressure increases due to the increase in volume, and stress is applied to weak parts of the envelope 15, such as the joint between the glass substrate 1 and the rear glass plate 13, causing the glass substrate 1 to warp. The thin film formed on the glass substrate 1 may peel off. Furthermore, when injecting the protective fluid 16 into the envelope 15, it is difficult to inject the protective fluid 16 flush with the top surface of the rear glass plate 13 as shown in FIG. 10, and as shown in FIG. I feel like I'm lacking,
As shown in Figure 12, it is easy to become excessive. If the protective fluid 16 is insufficient and sealed with the resin 18 or the glass plate 19, as shown in FIG. easy to become. On the other hand, as shown in Figure 12,
When the protective fluid 16 is in an excessive state, the resin 18 and the glass plate 1
9, the excess protective fluid 16 flows around the injection hole 17, making it difficult or unreliable to bond with the resin 18 or adhesive 20. Therefore, as shown in FIG.
It was a hassle to wipe it off and seal it.

Means for Solving the Problems The present invention provides a thin film Bl which contains thin film E and L elements and an insulating protective fluid for the thin film KL elements in an envelope comprising a translucent front substrate and a back plate. , the panel is characterized in that porous glass is disposed in the insulating protective fluid injection hole of the envelope.

In other words, according to the above configuration, the moisture contained in the insulating protective fluid and the gas generated by the thin film KL element are adsorbed by the porous glass, and the thin film EL element is prevented from deteriorating due to moisture and gas. . Also, JP-A-55-
The entire structure can be made thinner than the one disclosed in Japanese Patent No. 124182, in which the moisture and absorber are housed in the envelope. moreover,
Not only when the protective fluid is injected into the envelope through the porous glass, but also after the protective fluid is injected into the envelope.
Even if the porous glass is placed in the injection hole, the excess protective fluid is absorbed by the porous glass, so that the protective fluid does not flow around the injection hole and make the seal difficult or unreliable. Moreover, by impregnating the porous glass with a gas such as dry nitrogen, it is possible to absorb the increase in internal pressure due to the expansion of the protective fluid due to the rise in ambient temperature or the heat generated by the operation of the thin-film KL panel. Highly reliable thin film B
CL spring strength is obtained.

Example Embodiments of the present invention will be described below with reference to all the drawings.

FIG. 1 is a sectional view of one embodiment of the present invention.

The figure is the same as FIG. 7 except for the following points, and the same parts are given the same reference numerals and their explanations will be omitted.

The thin film EL spring (V23) of this embodiment houses a thin film KL element 1°2 in an envelope 15 consisting of a glass substrate 1 and a rear glass plate 18, and is coated with insulating material such as silicone oil or silicone grease. In the one containing the protective fluid 16, on the outside of the injection hole 17 of the rear glass plate 13,
The lower surface of a non-porous glass 25 integrated around the porous glass 24 is adhered with an adhesive 26 and sealed with a resin 27.

The porous glass 24 has a porosity of 2 and has several tens to several thousand fine pores (average pore diameter of about 40X).
5 VOI%, specific surface area of 200 m''/2, dry apparent specific gravity of about 1.5, and has high water adsorption properties.

This porous glass 24 is created, for example, as follows. First, using silica sand (s1o+), boric acid (H, Bo,
s-B+OHN'zO-based borosilicate glass (Sin:
70 wt%.

B203; 23 wt%, Na0; 7 wt%
) and process it into a plate shape. Next, several hundred degrees Celsius
Heat treatment is performed at a temperature of Then, the number 10A
Separation of the entangled structure of the glass phase occurs on the order of , and the phase separates into a strength phase of Bt' Os N tl @ Sochi and a glass phase of S i021 and Nochi. @1 BHO; N ; r O phase is soluble in acid solution or hot water, so when acid treatment is performed, the BtO
+ The Na5O phase is dissolved and removed to obtain a porous glass 24 rich in EtiO and components (EliO and 96 components). This porous glass 24 has a diameter of 810 mm.
．． Since it is a component, it is chemically stable, and even if it comes into contact with the protective fluid 16, there will be no adverse effect on each other. The non-porous glass 25 may be manufactured separately from the porous glass 24 and then welded or bonded with an adhesive.
It can be formed integrally with In other words, porous glass becomes non-porous when reheated at an appropriate temperature, so for example, if the periphery of a plate-shaped porous glass is pressed into contact with a heating element heated to a predetermined temperature or higher, only the outer periphery becomes non-porous. Can be made into pores. After that, when one side of the porous glass 24 is brought into contact with the etching solution, the porous glass 24 is mainly etched because the etching rate of the porous tube glass 24 is higher than that of the non-porous glass 25. The upper surface of 24 is lower than the upper surface of non-porous glass 25.

FIG. 2 shows how to inject the protective fluid 16 after bonding the porous glass 24 and the non-porous glass 25 to the rear glass plate 13 with the adhesive 26 as described above. An enlarged sectional view of the main part is shown. In the figure, 28 is F1. This O-ring is made of raw rubber, etc.
An injection tube 29 is attached to the porous glass 24 via a ring 28 . In this state, the entire body is placed in a vacuum chamber and evacuated, and then the entire tip of the injection tube 29 is immersed in an insulating protective fluid 16 such as silicone oil. Protective fluid 16 is injected into envelope 15 through tube 29 and porous glass 24 . At this time, due to the excellent moisture adsorption effect of the porous glass 24, the moisture contained in the protective fluid 16 is adsorbed and removed by the porous glass 24, leaving the envelope 15 free of moisture. Fluid 16 can be injected.

Moreover, when the porous tube glass 24 is placed in the injection hole 17, the protective fluid 16 in the envelope 15 will not spill out after the injection of the protective fluid 16 is completed. Furthermore, if the injection of the protective fluid 16 is finished in a state where the porous glass 24 partially contains dry nitrogen, etc. and is sealed with the resin 27, it will be protected from the rise in ambient temperature and the temperature rise during operation of the thin-film KL panel 23. Fluid 1
6 expands (in 2, the dry nitrogen, etc. is compressed, absorbs the expansion of the protective fluid 16, prevents an increase in internal pressure, and thin film E
Gas such as dry nitrogen in the porous glass 24 that can prevent the L spring/l/28 from breaking is retained within the porous glass 24 and will not mix into the protective fluid 16.

FIG. 3 shows an enlarged sectional view of a main part of another embodiment of the present invention. In this embodiment, after the protective fluid 16 is injected into the envelope 15 from the injection hole 17 in the same manner as before, a cap 31 covering the top and side surfaces of the porous glass 24 with non-porous glass 30 is bonded. It was glued with Agent 2 O. In this embodiment, even if the protective fluid 16 is injected in an excessive amount as shown in FIG. 11, if the porous glass 24 is placed in the injection hole 17, the porous glass 24 will absorb the excess protective fluid 16. , the protective fluid 16 does not flow into the bonded portion by the adhesive 25, and bonding by the adhesive 25 does not become difficult or unreliable. In addition, the moisture contained in the protective fluid 16 is adsorbed and removed by the porous glass 24, and the thin film EL
The element 12 will not deteriorate.

FIG. 4 shows an enlarged sectional view of a main part of still another embodiment of the present invention. In this first embodiment, after the protective fluid 16 is injected into the envelope 15 through the injection hole 17, a porous glass 24 is bonded to the injection hole 17 with an adhesive 2, and a dish-shaped glass plate is placed on the outside of the porous glass 24. 32 is bonded with an adhesive 33. In this embodiment as well, since the porous glass 24 absorbs excess protective fluid 16 when bonding the porous glass 24, it is likely that the protective fluid 16 will flow into the bonded area, resulting in difficulty in bonding or poor bonding. Moreover, since the cavity 84 is formed outside the porous glass 24, it is more advantageous against thermal expansion of the protective fluid 16 due to an increase in ambient temperature or a temperature increase due to the operation of the thin film KL spring p itself.

In addition to the above-mentioned embodiments, the present invention includes all embodiments in which porous glass is disposed in the injection hole.

Effects of the Invention As described above, in this invention, the porous glass is arranged in the protective fluid injection hole of the envelope, so that the moisture in the protective fluid can be adsorbed by the porous glass, and the thin film EL element due to moisture can be absorbed. In addition to preventing deterioration of the envelope, the porous glass also prevents the protective fluid injected into the envelope from leaking out, so it can be easily and reliably sealed. In addition, by incorporating a gas such as dry nitrogen into the porous glass, thermal expansion of the protective fluid due to increases in ambient temperature or thin-film EL panel temperature can be suppressed.
It is possible to prevent destruction of the envelope and peeling of the structure of the thin film EL element due to absorption by the gas and increase in internal pressure.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a thin film EL panel according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a main part for explaining a method of injecting an insulating protective fluid. FIG. 3 and FIG. 4 show thin film EL of other embodiments of this invention.
FIG. 3 is an enlarged sectional view of the main part of the panel. Figure 5 is a cross-sectional view of a thin-film EL element, Figure 6 is a plan view showing the relationship between the transparent electrode and the back electrode, Figure 7 is a cross-sectional view of a conventional thin-film EL panel, and Figure 8 is a conventional thin-film EL panel. j bladder K
Figure 9 is a cross-sectional view of the main part of the L panel, Figure 9 is a cross-sectional view of another conventional thin-film KL panel, and Figures 10 to 12 are enlarged views of the main part to explain problems when injecting insulating protective fluid. FIG. 1... Translucent front substrate (glass substrate), 2...
...Transparent electrode, 3.5...Dielectric layer, 4...Light emitting layer, 6...Back electrode, 13... ... Rear plate (rear glass plate), 1
5... Envelope, 16... Insulating protective fluid, 17...
・Injection hole, 24...Porous glass. 1] Fig. 1 Fig. 3 Fig. 1 Fig. 4 Fig. 9 Fig. 12 Fig. 5 Fig. 6 Fig. 7]] 1] 4 Fig. 8 Fig. 10 Fig. 1 Fig. 11 Fig. 12

Claims (1)

[Claims] A thin film E is provided in an envelope consisting of a translucent front substrate and a back plate.
A thin film EL panel comprising an L element and an insulating protective fluid, characterized in that a porous glass is disposed in an injection hole for the nj1 supinated envelope rim protective fluid. The present invention relates to a structure for sealing an insulating protective fluid injection hole, which is an effective technology for an EL display panel in which a thin film EL element that emits light (luminescence) is housed together with an insulating protective fluid in an envelope.