TW502552B - UV-cut film of organic electroluminescent display - Google Patents

Abstract

The present invention discloses an UV-cut film of organic electroluminescent display. The film is formed below the positive electrode (ITO conductive layer) or outside the glass substrate (illuminating face) of an organic electroluminescent display by sputtering. The film is able to prevent the organic electroluminescent display from shortening the lifetime due to decomposition of electroluminescent material in the display caused by illumination of external UV light in the operating process. The UV-cut film is formed by alternating stacked layers. In accordance with the present invention, the UV-cut film can filter out the incident light with a wavelength smaller than 400 nm, thereby effectively preventing the UV light from decomposing the electroluminescent material. In addition to filtering out the UV light, if the substrate of the organic electroluminescent display is a plastic substrate, the UV-cut film coated on the plastic substrate can prevent water and oxygen from entering into the electroluminescent layer via the plastic substrate, which may damage the electroluminescent material.

Description

502552 V. Description of the invention (l) Field of the invention The present invention relates to a film that can filter UV light, and particularly to a UV-resistant film suitable for organic electroluminescent display. Description of related technologies The earliest discovery of organic electroluminescence (oEL) can be traced back to 1963. Pope et al. Applied high voltage to Anthracene crystals to produce luminescence. Until 1987, Tang et al. Used vacuum deposition technology to produce organic low-molecular electrical excitation light elements with small molecules as the light-emitting layer, which stimulated the research craze for organic electrical excitation light. In 1990, the Cavendish Laboratory of the University of Cambridge, UK, published an organic polymer electro-optical light-emitting device made of polyphenylene vinylene (p-phenylene vinylene) (PPV). The characteristics and simple process have caused extensive research in all walks of life. The general organic electroluminescent display is shown in Figure 1. It is mainly made of glass or plastic substrate 10, transparent positive electrode indium tin oxide (IT0) u, organic electroluminescent film 12 (NPB, Alq3 or PPV), and inorganic protection. A film layer (Passivation Layer) 13, a metal negative electrode 14, a glass packaging cover 15 and a packaging resin 16 are composed. When a voltage is applied to the organic electroluminescent display, electrons and holes are injected from the positive electrode U and the negative electrode 14 into the organic light-emitting film layer 12, respectively. The combination of the electron and the hole forms an exconon and releases light. Since the metal negative electrode i 4 and the organic electroluminescent film 12 are easily oxidized and cracked by water and oxygen, the metal negative electrode 14 must be encapsulated with a glass packaging cover 15 to isolate water and oxygen and protect the display. Organic electroluminescence displays are generally made of glass cover 5

Resin (epoxy) 16 is directly displayed in _ w package. In addition, in order to avoid the low-fat direct encapsulation of the negative electrode and the light-emitting film layer during the packaging process, the photoresist layer of the epoxy resin is cracked, which affects the shape of the body: the electrode and organic hair are negative electrodes. 14 The upper layer has a luminous characteristic of 15 'so it is in gold Uyer). X The protective layer of SlN2 or Si 02 (passivation of the organic light-emitting film inside the electroluminescent display is damaged by water and wire 17, which is very sensitive to damage. This must be effectively shielded. Organic light-emitting materials are more severely damaged by ultraviolet rays. These are mainly high-secondary materials, especially pvv series materials whose polymer main chain contains conjugated double bonds. K. Tada et al. Found that conjugated double bonds are exposed to ultra-violet light in the presence of a very small amount of oxygen. After a few minutes of irradiation, it will be cleaved due to the oxidation of the main chain, resulting in a decrease in the fluorescence intensity (Photoluminescence Intensity), a blue shift in the fluorescence wavelength, and a rapid decrease in the electroluminescence intensity (Electroluminescence Intensity). The thin electrode (Cathode) is also unable to resist the damage of ultraviolet light. For other types of high-molecular or low-molecular blue light materials, although there is no group that quickly breaks down, it can absorb the peak distribution range of the blue light-emitting material. Mostly in the ultraviolet region (< 400 nm), which is prone to continuous fluorescent emission due to the action of ultraviolet light for a long time, resulting in organic light-emitting films Aging of the layer. Summary and purpose of the invention: In view of this, the object of the present invention is to provide a UV-resistant film, which can effectively solve the problem of ultraviolet radiation by introducing the UV-resistant film into the structure of an organic electroluminescent display. Light generated by materials inside organic electroluminescent display

502552 V. Description of the invention (3) Cracking problem, prolong the service life of the display. Another object of the present invention is to provide an anti-uv film which, when used in organic electroluminescent display using plastic as a substrate, has the effect of blocking water and oxygen from penetrating into the display in addition to filtering liver light. According to the present invention, as shown in the organic electroluminescence display of FIGS. 2 and 3, the UV-resistant film can be disposed between the glass substrate 20 and the film layer 21 (FIG. 2) or the outer layer of the glass substrate 30 (FIG. 3 Figure). As a result, as shown in Figure 6, it can effectively block the irradiation of ultraviolet rays (especially wavelengths below 400 nm), and completely filter out the wavelengths below 375 nm, so as to solve the problem of organic light-emitting materials cracking caused by ultraviolet light. In addition, the transmittance in the visible light region remains above 88%. The UV-resistant film of the present invention is composed of Ti02 and Si02 films formed by alternating lamination, but the material selection is not limited to this, and 2

Sub2 / MgF2, Ti205 / Si02, Ta2 05 / Si02, Ti017 / Si02,

Hf03 / Si02 and the like. The number of layers of the UV-resistant film is not particularly limited, so it is relatively tie. -Quan Jiafeng According to the present invention, an organic light-emitting display with an anti-function can also be provided. The display includes a glass or plastic substrate coated with IT0 on the surface, and the substrate is also coated with a UV-resistant film and organic electricity. Excitation light thin inorganic protective film and metal negative electrode; and a sealing label for covering the substrate. The display also includes epoxy resin for bonding and encapsulation. In the above display, the plastic substrate is selected from a polymer Polyethylene terephthalate, polyester, polyCarbonates, polyacrylic acid

502552

(polyacrylates), a group of materials consisting of poiystyrene. 'Furthermore, the organic electroluminescent film is an electroluminescent film such as a small molecule or a polymer. The small molecular electroluminescent film is coated by a vacuum evaporation method, and the polymer electroluminescent film is rotated. Coating, inkjet or screen printing method 7U to form a coating film. The material of the metal negative electrode is selected from Ca Ag% Mg A1, Li and other metal materials or composite metal materials with low work function. The metal negative electrode It is completed by vacuum thermal evaporation or sputtering. In addition, the inorganic protective film layer is selected from dielectrics of insulating oxide (Oxide), carbide (Carbide), nitride (Nitride) or a mixed type of dielectric. Matter (dielectric compound). The mixed type dielectric materials are SiNx, SiOx, SiONx, A1NX, A1CX, and the like. The inorganic protective film layer is obtained by vacuum sputtering (Sputter), chemical vapor deposition, or other methods using conventional techniques. According to the UV-resistant film of the present invention, incident light having a wavelength of less than 400 nm can be filtered out, effectively preventing ultraviolet light from causing cracking of the organic light-emitting material, and prolonging the service life of the display. Brief Description of the Drawings Figure 1 shows the basic structure of a conventional electro-luminescent display 1§. Figures 2 and 3 show the basic structure of an organic electroluminescent display with a UV-resistant film in an embodiment of the present invention. Fig. 4 shows a basic structure of an organic electroluminescent display without a UV-resistant film in a comparative example of the present invention.

0338-6518BfF; 90015; phoebe.ptd page 8 5. Description of the invention (5) Electromechanical hairpin display In the embodiment of the present invention, the basic structure of an electromechanical excitation display with an anti-uv film is shown. Penetrate ^ 6. Figure 7 shows the UV-resistant film of the present invention for light of various wavelengths. Figure 9 shows the current and brightness of the organic "light-emitting display" in the comparative example of the present invention. Figure 4 Fig. 12 is a diagram showing the relationship between the current g and the brightness vs. voltage of the organic electro-excitation light display g with anti-evaluation film in the embodiment of the present invention. Explanation of L symbols] Substrate ~ 10, 20, 30, 40, 50; Positive electrode Indium tin oxide (ITO) ~ 11, 21, 31, 41, 51; Organic electroluminescent film ~ 12, 22, 32, 42, 52; Inorganic protective film layer ~ 13, 23, 33, 43, 53; Metal Negative electrode ~ 14, 24, 34, 44, 54; encapsulated resin ~ 16, 26, 36, 46, 56; UV light] 7, 27, 37, 47, 57; UV-resistant film ~ 28, 38, 58. The comparative example uses I TO glass as the substrate of an organic electroluminescent display. The organic film used therein includes two layers: PEDOT (as a hole-transporting layer) and MEH-PPV (as a light-emitting layer). The metal negative electrode is calcium ( Ca) and silver (Ag) two layers were used to fabricate a polymer organic electro-optical excitation light device as shown in Figure 4, followed by irradiation with ultraviolet light (3 65 nm, 0 9 mff), and measuring the amount of light illuminated the current element, the fluorescent brightness and spectral characteristics of the present investigation is not used

V. Description of the invention (6) The results of the invention's anti-UV film material are confirmed, and the results obtained are as the anti-ultraviolet effect of the 7th bacterium organic electro-excitation light element. Indicates the brightness, the X axis is electric: f shows the current density ’and ·), _ 二 (:) 二! ^ Is the current density ma / rm2 λ- Μ, the redundancy is 7 73 0 cd / in2, and the current is about 441 is 311: J light 6Q minutes later, '⑹The current drops' shown in Figure 8 The shell degree decreased to 4674 Cd / m2. After being irradiated with ytterbium 120, as shown in Fig. 9, 'the current drops to 138 — Ϊ is the above result shows that it does not have a UV-resistant film. ^ The material is cracked and damaged after being irradiated with ultraviolet light. The photoelectric characteristics are obvious. Example: ITO glass It is a substrate for an organic electroluminescent display, and the organic medium layer used includes two layers of a foot T (as a hole transfer layer) and a surface_ppv (as a light emitting layer). The metal negative electrode is composed of two layers of calcium (Ca) and silver (Ag), and is shown in the table below: The film material and film thickness are made into f, and there are twelve film layers. Fabrication of electromechanical excitation light components. Table 1 502552 V. Description of the invention (7) Film type thickness (nm) 1 Ti02 18.43 2 Si02 56.34 3 Ti02 39.89 4 Si02 47.80 5 Ti02 36.63 6 Si02 66.55 7 Ti02 31.45 8 Si02 54.00 9 Ti〇2 43.80 10 Si. 2 49.32 11 Ti〇2 23.22 12 Si〇2 303.19 Next, ultraviolet light irradiation (365 nm, 0.9 mW) was performed, and the current, brightness, and fluorescence spectral characteristics of the device were measured, and the resistance using the present invention was investigated. UV film anti-ultraviolet effect. The obtained results are shown in Figures 10 to 12. Among them, ♦ represents the current density and brightness, the X axis is voltage (V), the left Y axis is the current density (mA / cm2), and the right Y axis is Brightness (Cd / m2). Figure 10 shows the photoelectric characteristics of the display with a UV-resistant film of this example. After the element is irradiated with ultraviolet light for 60 minutes, as shown in Figure 11, the current and brightness of the element are changed from the original 355 mA / cm2 and 7256 cd / m2 drops to 335 mA / cm2 and 5630 cd / m2. After 120 minutes of irradiation, as shown in Figure 12, the current and brightness of the device decreased to 224 mA / cm2 and 5489.

0338-6518TWF; 90015; phoebe.ptd Page 11 V. Description of the invention (8) C, f / lD "The above results show that after the element is irradiated with ultraviolet light, its brightness and electrical μ decrease are significantly slower than those in the comparative example. Display with anti-liver film. According to the above results, the organic electro-excitation with anti-binding film according to the present invention can effectively prevent the ultraviolet light from knowing the organic light-emitting material, thereby extending the life of the display. Limited hair =: = J = expose; as above, but it is not used within the scope, when it can be: = 者, without departing from the spirit of the present invention, see the attached application: ^ 2 and retouching 'therefore the present invention The protection of J < Jiayin patents shall prevail.

Claims (1)

502552 6. Scope of patent application 1. A UV-resistant thin film for organic electroluminescent display is composed of Ti0 2 and s 1 0 2 film layers alternately laminated. 2 · The UV-resistant film as described in item 1 of the scope of the patent application, wherein the film layers of Ti 02 and Si02 can be sub2 / MgF2, T "〇5 / Si02, Ta2 05 / Si02, ΊΆ 7 / Si02, Hf03 / Si. 2 etc. 3. 3. The UV-resistant film according to item 1 of the patent application scope, wherein the number of layers of the UV-resistant film is 8 to 16. 4. The UV-resistant film according to item i of the patent application scope, wherein The number of layers of the anti-UV film is 12. 5 · — An organic electroluminescent display comprising: a glass or plastic substrate, the surface of which is plated with IT0, an anti-UV film, an organic electroluminescent film, an inorganic protective film, and a metal negative Electrodes; and a package cover to cover the substrate. 6 · The organic electroluminescent display as described in item 5 of the scope of patent application, wherein the display further includes an epoxy resin for bonding the package. 7 · If a patent is applied The organic electroluminescent display as described in the fifth item, wherein the plastic substrate is a material selected from polyethylene terephthalate, poly (? 〇15 ^ 8 七 61〇, polycarbonate) , Polyacrylates, or polystyrene styrene). § • The organic electroluminescent display as described in item 5 of the patent application scope, wherein the UV-resistant film is made of a material selected from Ti02 / Si02 film, Sub2 / MgF2 film, Ti2 05 / Si02 film, Ta2 05 / Si02 film, Ti01.7 / Si02 film or Hf03 / Si02 film. 0338-6518TWF; 90015; phoebe.ptd Page 13 502552 6. Application scope of patent 9 · The organic electric light emitting display as described in item 5 of the scope of patent application, wherein the organic electroluminescent film is a small 7 knife or polymer electric Excitation light film. I 0 · The organic electroluminescent display as described in item 9 of the scope of the patent application, wherein the thin-molecule electroluminescent light thin film is completed by vacuum evaporation. II. The organic electroluminescent display as described in item 9 of the patent application scope, wherein the polymer electroluminescent film is coated by spin coating, inkjet or screen printing. 1 2. The organic electroluminescent display as described in item 5 of the scope of patent application, wherein the material of the metal negative electrode is selected from Ca, Ag, j | g, ai, Li and other metal materials or composites with low work function metallic material. 1 3 · The organic electroluminescent display as described in item 12 of the scope of patent application, wherein the metal negative electrode is completed by vacuum thermal evaporation or sputtering 1 4 · As described in item 5 of the scope of patent application An organic electroluminescent display, wherein the inorganic protective film is a dielectric compound selected from insulating oxides, carbides, nitrides, or a combination thereof. 15 · As described in item 14 of the scope of patent application, Electromechanical excitation light display, wherein the mixed type of dielectric substance is SiNx, SiOx, SiONx, AINx, AlCx, and the like. 16. The organic electroluminescent display according to item 14 of the scope of application for a patent, wherein the inorganic protective film is formed by vacuum sputtering (Sputter) or chemical 0338-651BTWF; 90015; phoebe.ptd Page 14 502552 6. Scope of patent application It is obtained by vapor deposition. Hill 0338-6518TWF; 90015; phoebe.ptd p. 15