KR20000009716A - Organic el-display device - Google Patents

Abstract

PURPOSE: Organic EL-display device has a protective layer having a superior absorption, and enhances a stability of components. CONSTITUTION: Organic EL-display device has a laminated structure having organic lamination layer(25) between the first and second electrodes(23,27). The organic EL-display device includes absorption material having P2O5 and antioxidant material. The antioxidant material is comprised of alkali salt or a metal, or includes all of the alkali salt and metal. Thereby, the organic EL-display device has a protective layer(29) having a superior absorption, and enhances a stability of components.

Description

Organic light emitting diode

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent device, and more particularly to a hygroscopic agent used in a protective film of an organic electroluminescent device.

Recently, as the size of display devices (displays) increases, the demand for flat display devices with less space is increasing. One of such flat display devices is an electroluminescent device.

The electroluminescent device is largely divided into an inorganic electroluminescent device and an organic electroluminescent device according to the material used.

In general, the inorganic electroluminescent device is a device that accelerates electrons by applying a high electric field to the light emitting part, and thus emits light by exciting the emission center by colliding the accelerated electrons with the light emitting center.

In the organic light emitting diode, the excitons generated by combining the injected electrons and holes by injecting electrons and holes from the electron injection electrode and the hole injection electrode into the light emitting unit are respectively grounded from the excited state. It is a device that emits light when falling.

Since the inorganic electroluminescent device having the above operating principle requires a high electric field, a high voltage of 100 to 200 V is required as a driving voltage, whereas the organic electroluminescent device can be driven at a low voltage of about 5 to 20 V. There is an advantage, and research is being actively conducted.

In addition, the organic light emitting display device has excellent characteristics such as wide viewing angle, high speed response and high contrast, so it can be used as a pixel of a graphic display, a TV image display or a surface light source. They are thin, light, and have good color, making them suitable for next-generation flat panel displays.

However, one of the biggest problems in the practical application of the organic light emitting display device is its short lifetime.

There are many reasons for determining the lifetime of a device, but the main causes are impurities in organic material, interface between organic material and electrode, low crystallization temperature (Tg) of organic material, oxidation of device by oxygen and moisture. Can be.

In more detail, impurities in the organic material trap electrons, holes, and the like, leak current, increase organic crystallization, and ultimately shorten device life. If the interface state between the electrode and the organic material is not good, injection of charges (electrons or holes) becomes difficult, and a large amount of current flows in part, which may damage the organic material.

In addition, in addition to the interface between the electrode and the organic material, there is a problem when the interface state between the organic material and the organic material is not good.

That is, interdiffusion occurs at the interface between the organic hole transport layer (HTL) and the emitting layer (EML), and the light emitting layer material prevents the movement of holes in the hole transport layer and the hole transport layer material is Interfering with the movement of electrons in the light emitting layer causes a problem of lowering the luminous efficiency.

In addition, the low crystallization organic material is crystallized inside the device is excited (excited) molecules do not emit energy to the light, the transition to the non-luminescent energy level to reduce the luminous efficiency and shorten the lifetime.

However, such problems can be solved by improving the interface by purifying organic matter, developing a material having a high crystallization temperature, and introducing a material that increases adhesion to the interface between the organic material and the electrode. It is removal.

Moisture and oxygen that oxidize the device may already exist inside the device and penetrate from the outside during the manufacturing process. In the latter case, moisture and oxygen enter the microholes of the device, and the organic film and metal Is oxidized to lose its function as a light emitting device, which means that the light emitting area of the device is reduced.

In order to solve this problem, various absorbents can be applied to the organic light emitting device, the most powerful absorbent of which is phosphorus pentoxide (P ₂ O ₅ ).

Phosphorous pentoxide is a chemical reaction that absorbs water and becomes phosphoric acid, unlike physical adsorption mechanisms of physical adsorption such as alumina and silica gel.

On the other hand, as the structure of the organic light emitting device to which the adsorbent is applied, conventionally adsorbent to the cover plate (cover plate) to the device, and then adhered to the substrate by using the sealing capper plate to the encapsulant to block moisture and oxygen A method (Japanese Patent Laid-Open No. 9-148066) has been proposed, and a method (Japanese Laid-Open Patent Publication No. 3-261091) in which a support layer is introduced is also proposed to prevent the adsorbent from falling onto the device.

That is, as shown in FIG. 1, Japanese Patent Laid-Open No. 9-148066 includes a glass substrate 1, a first electrode 2, and an organic laminated film (hole injection layer or hole transport layer, light emitting layer, electron injection layer, or electron transport layer). (3), a cover plate (6) is formed on the organic light emitting device having the second electrode (4), and metal oxide, alkali metal oxide, alkaline earth metal oxide, sulfate or metal halide compound on the cover plate (6). A layer composed of a moisture absorbing layer 5 was formed to block moisture and oxygen. The moisture absorption layer may be adhered to the cover plate by using a method such as vacuum deposition, sputtering, spin coating, etc., and the adhered cupper plate may be adhered to the substrate using the encapsulant 7.

Such a method can absorb moisture of the device as the moisture absorbing layer, but there is a risk that an adsorbent such as a metal oxide or an alkali metal oxide in the moisture absorbing layer may fall on the device due to an external impact, or the like. Adsorbents that can corrode the device when dropped cannot be introduced into the structure.

In order to solve such a structural problem, Japanese Patent Laid-Open No. 3-261091 shown in Fig. 2 has been proposed.

The overall structure of FIG. 2 is similar to that of FIG. 1, except that the support layer 8 is introduced at the lower portion of the absorbent layer 5 to prevent the absorbent from falling onto the device.

However, even in this case, there is a problem in using phosphorus pentoxide, which is the most powerful adsorbent.

That is, phosphorus pentoxide absorbs moisture as an adsorbent of the device. In this case, phosphorus pentoxide (P ₂ O ₅ ), an phosphate anhydride, absorbs water and becomes liquid phosphoric acid (H ₃ PO ₄ ) in the solid phase. This is due to the fact that the melting point of pure phosphoric acid is 42.35 degrees, so that it exists in liquid phase at room temperature depending on the amount of moisture. Therefore, in general, since acid has a property of corroding by oxidizing a material having a greater tendency to ionize than hydrogen, liquid phosphoric acid may adversely affect the device through the support layer.

In addition, phosphorus pentoxide may be a problem due to its acidity even when the organic electroluminescent device is disposed of later.

The present invention has been made in order to improve the above-mentioned conventional problems, an object of the present invention is to form a protective film containing a strong absorbent called phosphorus pentoxide (P ₂ O ₅ ) to extend the life of the organic light emitting device, the moisture absorbent The present invention provides an organic light emitting device that can solve the problem of oxidation or corrosion caused by the use of the device, and also provides an organic light emitting device having a simple process of introducing the moisture absorbent into the device.

1 and 2 is a structural cross-sectional view showing an organic light emitting device according to the prior art,

3 and 4 are structural cross-sectional views showing an organic light emitting display device according to the present invention.

Explanation of symbols for main parts of the drawings

21 transparent substrate 23 first electrode

25 organic laminate film 27 second electrode

29: protective film 31: silicone oil or inert gas

33: support layer 35: moisture absorption layer

37 cover plate 39 encapsulant

The organic electroluminescent device according to the present invention is an organic electroluminescent device having a laminated structure including an organic laminated film between a first electrode and a second electrode, wherein phosphorus pentoxide (P ₂ O ₅ ) and at least one device It is characterized by including a moisture absorbent containing an antioxidant material.

In the present specification, the material for preventing the oxidation of an element means a material which performs a function of preventing the organic electroluminescent device from oxidizing and corroding by phosphoric acid formed by absorbing moisture of phosphorus pentoxide used as an absorbent, and the present invention. Plays a key role.

The device anti-oxidation material that plays such a role may be selected and used among alkali salts and metals, and may include both alkali salts and metals.

In this case, the alkali salt may be a mixture of one or two or more materials selected from phosphates, sulfates and carbonates, of which phosphates are Na ₃ PO ₄ , Na ₂ HPO ₄ , NaH ₂ PO ₄ , K ₃ PO ₄ , K ₂ HPO ₄ , KH ₂ PO ₄ , CaHPO ₄ , MgHPO _{4 It} may be a material selected by mixing one or two or more.

In addition, the metal may be selected from alkali metals, alkaline earth metals and metals having a higher ionization tendency than hydrogen, and include Na, K, Mg, Ca, Al, Cr, Mn, Fe, Co, Ni, Cu, and Zn powders ( powder may be selected.

The organic light emitting diode may further include a support layer of a moisture absorbent, and may further include a protective film formed on a laminate structure including the organic laminate.

The support layer is made of a polymer or glass, characterized in that having a pore of 0.01μm-10μm. The support layer made of the polymer is preferably polyethylene, polyurethane, polytetrafluoroethylene, polyamide, polyvinylchloride, polymethylmethacrylate, polypropylene, polyolefin, polycarbonate, polyethylene, cellulose, polyformaldehyde, It may consist of a material selected from polysulfone and polyethylene terephthalate.

In addition, when P ₂ O ₅ or P ₂ O ₅ and the antioxidant is added as described above, it can be introduced by mixing with the UV curing agent. The reason for adding the UV curing agent is to solve the problem that the particles in powder form during the process of introducing the absorbent is blown during the process. The UV curing agent may be used a silicone, acrylic, epoxy, urethane type. Such UV curing agent introduction portion may be omitted.

Hereinafter, an organic light emitting display device according to the present invention will be described with reference to the accompanying drawings.

3 and 4 are schematic diagrams for explaining the structure of the organic light emitting display device according to the present invention.

As shown in FIG. 3, the transparent substrate 21, the first electrode 23, the organic laminated film (composed of the hole injection layer or the hole transport layer, the light emitting layer, the electron injection layer or the electron transport layer) 25, the second electrode ( A cover plate 37 is formed on the organic light emitting device having the 27), and a moisture absorption layer 35 containing phosphorus pentoxide (P ₂ O ₅ ) is formed under the cover plate 37. The moisture absorbing layer 35 is bonded to the cover plate 37 by vacuum deposition, sputtering, spin coating, or the like, or forms a trench in the lower portion of the cover plate 37 to form phosphorus pentoxide (P ₂ O _5). The moisture absorbing layer 35 may be injected to form the moisture absorbing layer 35.

The moisture absorbing layer contains at least one material for preventing oxidation of the device, which is a material capable of preventing the device from being oxidized and corroded by phosphoric acid formed by moisture absorption.

The device antioxidant material may be a metal or an alkali salt.

The related action when a moisture absorption layer is formed by mixing with phosphorus pentoxide using a metal, particularly an alkali metal, an alkaline earth metal or a metal having a greater ionization tendency than hydrogen as the device anti-oxidation material, is as follows.

Phosphorous pentoxide used as the moisture absorbent in the present invention absorbs moisture to become phosphoric acid. At this time, before the phosphoric acid in the liquid phase oxidizes the organic electroluminescent layer and the metal to oxidize the device, the metal having a greater tendency to ionize than the alkali metal, alkaline earth metal or hydrogen is oxidized to the protective film so as to oxidize the nearby metal and lose its activity. To add.

That is, the alkali metal, alkaline earth metal, or metal having a greater ionization tendency than hydrogen gives electrons to phosphoric acid and oxidizes itself. As the metal, Na, K, Mg, Ca, Al, Cr, Mn, Fe, Co, Ni, Cu, Zn powder may be selected.

On the other hand, there is an alkali salt as described above as another substance for preventing oxidation of the element besides the metal. The alkali salts refer to alkali salts that show basicity (PH 7 or higher) when dissociated in water.

The action of the alkali salt in the moisture absorption layer is as follows.

Phosphorous pentaoxide absorbs water and becomes acidic phosphoric acid. At this time, the phosphate is formed through the movement of alkali metal ions, alkaline earth metal ions from the alkali salt in the process of phosphoric acid.

That is, a kind of neutralization reaction occurs in which hydrogen of phosphoric acid and alkali ions of alkali salts are exchanged.

The alkali salt is preferably a substance mixed with one or two or more of phosphate, sulfate, carbonate. The phosphate may be used by mixing together Na ₃ PO ₄ , Na ₂ HPO ₄ , NaH ₂ PO ₄ , K ₃ PO ₄ , K ₂ HPO ₄ , KH ₂ PO ₄ , CaHPO ₄ , MgHPO _4, and the like. By adjusting the amount of alkali salts during the preparation of P, the pH can be kept constant at 5-8 even during disposal.

As such, when the alkali salt is used as the material for preventing the oxidation of the element, when the phosphate forms the phosphate, the melting point becomes high, and thus, the melting point can be maintained in the solid phase, thereby preventing corrosion of the support layer and the cover plate. It is possible to maintain a constant pH according to the amount of alkali salts can solve the problem of acidic problems during the waste treatment. In addition, the alkali salt is also excellent in the moisture absorption of moisture does not significantly affect the moisture absorption capacity.

When the phosphorus pentoxide is used as the hygroscopic agent, as mentioned above, phosphorus pentoxide and metal or phosphorus pentoxide and alkali salt may be mixed and both metal and alkali salt may be mixed and used together with phosphorus pentoxide.

As a next step, the cover plate 37 may be adhered to the substrate using an encapsulant 39 such as an epoxy adhesive.

Furthermore, as shown in FIG. 4, the organic light emitting diode may be manufactured by further including a support layer 33 of the moisture absorbing layer in order to prevent the moisture absorbent from falling onto the device.

The support layer of the moisture absorption layer may be made of a polymer or glass, it characterized in that having a pore of 0.01μm-10μm.

The material used for the support layer made of the polymer is as mentioned above.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(First embodiment)

3 is a schematic structural diagram of an organic light emitting display device according to the first embodiment of the present invention. This will be described in detail below.

Copper phthalocyanine (CuPc) is sequentially deposited as a hole injection layer on a transparent substrate coated with about 140 nm of ITO (Indium Tin Oxide) 21, which is a transparent electrode, as the first electrode. Next, N, N'-diphenyl-N, N'-bis (3-methylphenyl)-(1,1'-biphenyl) -4,4'-diamine (N, N'-diphenyl-N) as a hole transport layer , N'-bis (3-methylphenyl)-(1,1'-biphenyl) -4,4'-diamine; abbreviated as TPD) about 30 nm, and then 8-hydroxyquinoline aluminum (Alq ₃₎ as a green light emitting layer. ) Is formed by vacuum deposition about 50 nm. Subsequently, the electron injection layer or the electron injection / transport layer may be formed or omitted.

The second electrode layer 27 is formed by thinly coating an alkali metal oxide and a metal on the laminated plate structure 25 of the organic light emitting device formed as described above. Li ₂ O, Al, and the like may be formed to a thickness of about 50 nm as the second electrode layer.

A first passivation layer 29 is formed on the second electrode layer.

The first passivation layer 29 may be coated with an organic metal, a polymer, or the like through chemical vapor deposition (CVD), and this process may be omitted if necessary.

Next, a cover plate 37 is formed to cover and protect the substrate made above. The glass, plastic, or coated metal plate used as the cover plate 37 is concave to introduce a moisture absorbent to form a moisture absorbing layer 35, wherein the plastic material of the cover plate may be limited in the usable range depending on the thickness. However, it is usually advantageous to use PET, PBT, Nylon, PC (Polycarbonate), etc., and by plating metal on these polymers, a better effect can be obtained.

As the metal plate used as the cover plate 37 of the moisture absorption layer 35, aluminum, iron, copper, etc. may be used. However, when the metal plate is used, the metal plate may be corroded by an absorbent. The hydrophobic polymer may be coated inside.

Next, a process of forming a moisture absorbing layer 35 by putting an absorbent into the cover plate 37 will be described in detail.

The moisture absorbent is to use phosphorus pentoxide (P ₂ O ₅ ) as a function of absorbing moisture,

A moisture absorption layer 35 is formed by adding a device antioxidant material together with the phosphorus pentoxide. The device anti-oxidation material may be an alkali metal, an alkaline earth metal, or a metal having a higher ionization tendency than hydrogen, and may also be an alkali salt. Furthermore, a moisture absorption layer may be formed by using both alkali metal, alkaline earth metal, or a metal having a higher ionization tendency than hydrogen and an alkali salt together with phosphorus pentoxide.

Next, the cover plate 37 on which the second protective film is formed is bonded to the substrate. At this time, an epoxy adhesive is used as the sealing agent 39 to adhere.

(Second embodiment)

4 is a schematic structural diagram of an organic light emitting display device according to a second embodiment. This will be described in detail below.

After the first electrode 23 is formed on the substrate 21, the organic electroluminescent layer 25 is formed and the second electrode layer 27 is formed by thinly coating an alkali metal thereon.

A protective film 29 coated with an organic metal, a polymer, or the like by CVD may be formed on the second electrode layer 27. This process may be omitted.

Subsequently, after the cover plate 37 is formed, a moisture absorption layer 35 containing phosphorus pentoxide and an element antioxidant material is formed on the formed cover plate. Usable types of the device for preventing the oxidation of the material or the material or manufacturing process of the components that are not described are as described above in the present specification.

A feature of the second embodiment is to protect the device by introducing a support layer 33 so that phosphorus pentoxide of the moisture absorption layer 35, which is one of the gist of the present invention, does not fall on the device.

The support layer 33 can easily permeate the water molecules, but the moisture absorbent such as phosphorus pentoxide to adjust the pores so as not to fall into the device. The pores of the support layer are preferably adjusted within the range of 0.01 μm-10 μm.

In addition, the support layer 33 is a porous material made of a polymer or glass, and the support layer made of the polymer includes polyurethane, polytetrafluoroethylene, polyamide, polyvinylchloride, polymethylmethacrylate, polypropelin, Polyolefin, polycarbonate, polyethylene, cellulose, polyformaldehyde, polysulfone, polyethylene terephthalate and the like can be used. Preferably, polyethylene, polypropylene, polytetrafluoroethylene (teflon), etc., which are resistant to acids and bases, are used.

Next, the support layer 33 is adhered to and fixed to the cover plate 37 on which the moisture absorption layer 35 is formed.

That is, after coating a hot melt adhesive on the support layer 33, it is pressurized and melted to adhere to the cover plate 37 or pressurized and melted at a temperature at which the support layer 33 is melted without an adhesive to adhere to the cover plate 37. You can. Alternatively, the adhesive may be adhered to the support layer 33 or the cover plate 37 at room temperature.

Finally, the cover plate 37 is bonded to the substrate 21.

(Third Embodiment)

It is the same as Example 2 except the UV hardening | curing agent is comprised in the moisture absorption layer. As mentioned above, usable UV curing agents include silicone, acrylic, epoxy and urethane types.

According to the present invention, an organic electroluminescent device using a protective film made of phosphorus pentoxide and an alkaline substance, an organic electroluminescent device using a protective film made of phosphorus pentoxide only, and an organic electroluminescent device using alumina as a protective film were compared. Is as follows.

Sample A B C Absorbent P ₂ O ₅ P ₂ O ₅ + Na ₃ PO ₄ Alumina Sealing agent Epoxy Epoxy Epoxy Temperature 80 ℃ 80 ℃ 80 ℃ Humidity 50% 50% 50% Experiment time 72 hours 72 hours 12 hours Shrinkage 0% 0% 17.7% (305 μm-251 μm)

As can be seen from the above experimental results, it can be seen that there is no difference in the ability to absorb moisture even when Na ₃ PO ₄ is added to phosphorus pentoxide, and thus Na ₃ PO ₄ and the like. By using the device for preventing the oxidation of the device can be prevented from corrosion of the device can significantly improve the stability of the device.

In addition, by adding the UV curing agent to the protective film having a moisture absorption function, it is possible to prevent the powder component of the protective film from flying during the process.

In summary, the organic electroluminescent device according to the present invention has the following effects.

That is, the present invention is to provide an organic electroluminescent device using a powerful hygroscopic agent called phosphorus pentoxide (P2O5), while having the moisture absorption power as it is, without oxidizing or corroding the device, and further simplifying the manufacturing process.

Claims (30)

In the organic light emitting device having a laminated structure (laminated structure) comprising an organic laminated film between the first electrode and the second electrode, An organic electroluminescent device comprising a hygroscopic agent containing phosphorus pentoxide (P ₂ O ₅ ) and at least one device anti-oxidation material. The method of claim 1, The device for preventing oxidation of an organic light emitting device, characterized in that the alkali salt. The method of claim 1, The device for preventing oxidation of the organic light emitting device, characterized in that the metal. The method of claim 1, The device for preventing oxidation of an organic light emitting device, characterized in that it comprises both an alkali salt and a metal. The method of claim 1, An organic light emitting display device, characterized in that it further comprises a support layer of the moisture absorbent. The method of claim 1, The organic light emitting device further comprises a protective film formed on the laminated plate structure including the organic laminated film. The method of claim 1, An organic light emitting display device, characterized in that the moisture absorbent further comprises a UV curing agent. The method according to claim 2 or 4, The alkali salt is an organic electroluminescent device, characterized in that a mixture of one or two or more materials selected from phosphates, sulfates and carbonates. The method according to claim 3 or 4, The metal is an organic light emitting device, characterized in that selected from alkali metals, alkaline earth metals and metals having a greater tendency to ionize than hydrogen. The method of claim 5, The support layer is an organic light emitting device, characterized in that made of a polymer or glass. The method of claim 8, The phosphate is selected from one or two or more selected from Na ₃ PO ₄ , Na ₂ HPO ₄ , NaH ₂ PO ₄ , K ₃ PO ₄ , K ₂ HPO ₄ , KH ₂ PO ₄ , CaHPO ₄ , MgHPO ₄ An organic light emitting display device. The method of claim 9, The metal is an organic light emitting diode, characterized in that selected from Na, K, Mg, Ca, Al, Cr, Mn, Fe, Co, Ni, Cu and Zn powder (powder). The method of claim 10, The support layer is an organic light emitting device, characterized in that having a pore of 0.01μm-10μm. The method of claim 10, The support layer composed of the polymer is polyethylene, polyurethane, polytetrafluoroethylene, polyamide, polyvinyl chloride, polymethylmethacrylate, polypropylene, polyolefin, polycarbonate, polyethylene, cellulose, polyformaldehyde, polysulfone and An organic electroluminescent device, characterized in that consisting of a material selected from polyethylene terephthalate (Teflon). The method of claim 7, wherein The UV curing agent is an organic light emitting device, characterized in that selected from silicon, acrylic, epoxy, urethane type. In the organic light emitting device having a laminated structure (laminated structure) comprising an organic laminated film between the first electrode and the second electrode, An organic electroluminescent device comprising phosphorus pentoxide (P ₂ O ₅ ) and a moisture absorbent containing a substance selected from Na ₃ PO ₄ and K ₃ PO ₄ . The method of claim 16, An organic light emitting display device, characterized in that it further comprises a support layer of the moisture absorbent. The method of claim 16, The organic light emitting device further comprising a protective film formed on the laminated plate structure including the organic laminated film. The method of claim 16, An organic light emitting display device, characterized in that the moisture absorbent further comprises a UV curing agent selected from silicone, acrylic, epoxy, and urethane types. The method of claim 17, The support layer is an organic light emitting device, characterized in that selected from polyethylene, polypropylene and polytetrafluoroethylene. In the organic light emitting device having a laminated structure (laminated structure) comprising an organic laminated film between the first electrode and the second electrode, A cover plate formed to cover the upper front and side surfaces of the laminated plate structure including the organic laminate film; A film formed under the cover plate, the moisture absorbing layer including phosphorus pentoxide (P ₂ O ₅ ) and at least one antioxidant material; And An organic light emitting display device, characterized in that consisting of a support layer made of polymer or glass formed under the moisture absorption layer. The method of claim 21, The organic light emitting device further comprises a protective film formed on the laminated plate structure including the organic laminated film. The method of claim 21, The device for preventing oxidation of an organic light emitting device, characterized in that the alkali salt. The method of claim 21, The device for preventing oxidation of the organic light emitting device, characterized in that the metal. The method of claim 21, The device for preventing oxidation of an organic light emitting device, characterized in that it comprises both an alkali salt and a metal. The method of claim 21, The organic light emitting device, characterized in that the moisture absorption layer further comprises a UV curing agent selected from silicon, acrylic, epoxy, urethane type. The method of claim 23 or 25, The alkali salt is an organic electroluminescent device, characterized in that a mixture of one or two or more materials selected from phosphates, sulfates and carbonates. The method of claim 24 or 25, The metal is an organic light emitting device, characterized in that selected from alkali metals, alkaline earth metals and metals having a greater tendency to ionize than hydrogen. The method of claim 27, The phosphate is selected from one or two or more selected from Na ₃ PO ₄ , Na ₂ HPO ₄ , NaH ₂ PO ₄ , K ₃ PO ₄ , K ₂ HPO ₄ , KH ₂ PO ₄ , CaHPO ₄ , MgHPO ₄ An organic light emitting display device. The method of claim 28, The metal is an organic light emitting diode, characterized in that selected from Na, K, Mg, Ca, Al, Cr, Mn, Fe, Co, Ni, Cu and Zn powder (powder).