Encapsulation structure for encapsulating organic light-emitting diode

Abstract

The present application provides an encapsulation structure for encapsulating an organic light-emitting diode. The encapsulation structure is composed of only two layers, i.e., an organic barrier layer and an inorganic barrier layer, the organic barrier layer is in contact with the organic light-emitting diode, and the inorganic barrier layer is attached on the organic barrier layer, wherein the organic barrier layer is formed from a photocurable composition, and the photocurable composition comprises, in parts by weight, 5-20 parts by weight of a silicon-based photocurable monofunctional monomer, 30-50 parts by weight of a silicon-based photocurable difunctional monomer, 20-60 parts by weight of a non-silicon-based photocurable monomer, and 1-10 parts by weight of a photoinitiator. The encapsulation structure of the present application has only two layers, so that the development requirements of an OLED device towards light weight, thin thickness, and low cost are met. In addition, compared with the prior art, the erosion of the OLED device by moisture and / or oxygen can be better inhibited, so that the reliability of the OLED device is improved and the service life thereof is prolonged.

Description

A packaging structure for packaging organic light-emitting diodes

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to a Chinese patent application filed with the Patent Office of China on August 25, 2023, with application number "2023110762956" and application name "A packaging structure for encapsulating organic light-emitting diodes", the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application belongs to the technical field of electronic device packaging, and specifically relates to a packaging structure for packaging organic light emitting diodes. Background Art

[0004] Organic Light Emitting Diodes (OLEDs) are electroluminescent devices that convert electrical energy into visible light. Compared to traditional LEDs, OLEDs offer advantages such as active illumination, low drive voltage, high luminous efficiency, ultra-thin and lightweight design, low cost, high response speed, and flexibility. Therefore, they are expected to become the mainstream of next-generation display devices, attracting the attention of relevant R&D institutions.

[0005] At present, the industrial development and application of flexible OLED devices have problems such as insufficient stability, lack of reliability and service life. This is mainly because the materials and structures in OLED devices are more sensitive to water vapor, oxygen and heat, and can easily react with water vapor, oxygen and other components in the air, thereby causing the failure of OLED devices. Therefore, strict packaging of flexible OLED devices is the only way to achieve mass production of flexible OLED devices. Currently, the more mainstream packaging method for flexible OLED devices is Barix packaging technology, which is an inorganic-organic overlapping multi-layer packaging structure, that is, an organic layer is coated on the inorganic layer, which can not only fill the defects of the inorganic layer, but also extend the path for water vapor and oxygen to enter the OLED device, thereby improving the high barrier performance.

[0006] To effectively inhibit moisture or oxygen from penetrating into the organic light-emitting layer, the prior art typically employs a multi-layer packaging structure due to limitations in materials and other factors. For example, the Chinese patent publication (announcement) number CN101859792A, entitled "Organic Light-Emitting Diode Display and Method for Manufacturing the Same," describes an encapsulated OLED device structure comprising a five-layer structure comprising a moisture absorption layer, a first barrier layer, a first auxiliary barrier layer, a second barrier layer, and a second auxiliary barrier layer. Although this patent inhibits moisture and / or oxygen erosion of the OLED device to a certain extent through the five-layer packaging structure, the excessive number of layers increases the weight and thickness of the device, hindering the development of OLED devices toward simpler, thinner structures, more controllable processes, and lower costs.

[0007] In view of this, the present application provides a packaging structure for encapsulating an organic light emitting diode to solve the above technical problems.

[0008] Summary of the Invention

[0009] The purpose of this application is to overcome the shortcomings of the above-mentioned prior art and propose a packaging structure for encapsulating organic light-emitting diodes. The packaging structure consists of only one organic barrier layer and one inorganic barrier layer, and the organic barrier layer is formed by irradiating ultraviolet light using the photocurable composition provided by this application. The OLED device formed thereby can better inhibit the corrosion of moisture and / or oxygen on the OLED device while meeting the development trend of light weight, thin thickness and low cost, thereby improving the reliability and service life of the OLED device.

[0010] In order to achieve the above objectives, this application adopts the following technical solutions:

[0011] The present application provides a packaging structure for encapsulating an organic light-emitting diode, wherein the packaging structure is composed of two layers: an organic barrier layer and an inorganic barrier layer. The organic barrier layer is formed of a photocurable composition, and the outgassing amount of the organic barrier layer is less than 10 ppm, and the plasma etching rate is less than 7%.

[0012] The organic barrier layer is in contact with the organic light emitting diode, and the inorganic barrier layer is adhered to the top of the organic barrier layer.

[0013] Furthermore, the photocurable composition includes the following components (A) to (D):

[0014] (A) component: silicon-based photocurable monofunctional monomer,

[0015] (B) component: a silicon-based photocurable bifunctional monomer,

[0016] (C) component: a non-silicon-based photocurable monomer,

[0017] (D) ingredient: photoinitiator;

[0018] The photocurable composition comprises, by weight, 5 to 20 parts of a silicon-based photocurable monofunctional monomer, 30 to 50 parts of a silicon-based photocurable difunctional monomer, 20 to 60 parts of a non-silicon-based photocurable monomer, and 1 to 10 parts of a photoinitiator.

[0019] Furthermore, the silicon-based photocurable monofunctional monomer is represented by structural formula (1):

[0020] In the structural formula (1), R1, R2, and R3 are each independently any one of a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C1-C20 alkoxy group, a substituted or unsubstituted C3-C20 cycloalkyl group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C3-C30 heteroaryl group, and a substituted or unsubstituted C7-C30 aralkyl group;

[0021] X is a single bond, O, S, NH or NR', wherein R' is any one of a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C3-C10 cycloalkyl group, and a substituted or unsubstituted C1-C10 aryl group;

[0022] Y is any one of a substituted or unsubstituted C1-C20 alkylene group, a substituted or unsubstituted C1-C20 alkyleneoxy group, a substituted or unsubstituted C3-C20 cycloalkylene group, and a substituted or unsubstituted C6-C30 arylene group;

[0023] R4 is hydrogen or methyl.

[0024] Furthermore, the silicon-based photocurable bifunctional monomer is represented by structural formula (2):

[0025] In structural formula (2), Y1, Y2, Y3, Y4, Y5, and Y6 are each independently hydrogen, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C1-C20 alkoxy group, a substituted or unsubstituted C3-C20 cycloalkyl group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C3-C30 heteroaryl group, or a substituted or unsubstituted C7-C30 aralkyl group;

[0026] Preferably, Y1, Y2, Y3, Y4, Y5, and Y6 contain substituted or unsubstituted C6-C30 aryl groups.

[0027] Y7 and Y8 are each independently any one of a single bond, a substituted or unsubstituted C1-C20 alkylene group, a substituted or unsubstituted C1-C20 alkyleneoxy group, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C7-C30 arylalkylene group;

[0028] Y9 and Y10 are each independently hydrogen or methyl.

[0029] Specifically, the silicon-based photocurable bifunctional monomer includes but is not limited to the following structural formula:

[0030] Furthermore, the non-silicon-based photocurable monomer does not contain silicon and has one or more photocurable functional groups.

[0031] Furthermore, the non-silicon-based photocurable monomer is a mixture of a monofunctional monomer and a multifunctional monomer, and the weight ratio of the monofunctional monomer to the multifunctional monomer is (1:0.1) to (1:10).

[0032] Furthermore, the monofunctional monomer is a mixture of at least two mono(meth)acrylate monomers to optimize the inkjet printing performance of the photocurable composition and achieve good leveling and film-forming properties.

[0033] The mono(meth)acrylate monomer includes a cyclic mono(meth)acrylate and / or an aliphatic mono(meth)acrylate. The cyclic mono(meth)acrylate preferably has a viscosity of ≤15 cps at 25°C, and specifically may include one or more of cyclohexyl methacrylate (1-5 cps at 25°C), isobornyl methacrylate (2-10 cps at 25°C), tetrahydrofurfuryl methacrylate (4-10 cps at 25°C), and 2-phenoxyethyl methacrylate (5-15 cps at 25°C). Cyclic mono(meth)acrylates with a viscosity of ≤15 cps at 25°C have excellent leveling and high spreading properties, and can be cured to form a uniform, smooth film on an organic light-emitting diode. The aliphatic mono(meth)acrylate includes a (meth)acrylate containing a branched or linear alkyl group, specifically including any one of methyl(meth)acrylate, ethyl(meth)acrylate, butyl(meth)acrylate, 2-hydroxyethyl(meth)acrylate, 2-hydroxybutyl(meth)acrylate, hexyl(meth)acrylate, octyl(meth)acrylate, nonyl(meth)acrylate, decyl(meth)acrylate, undecyl(meth)acrylate, and dodecyl(meth)acrylate.

[0034] Preferably, in order to balance the mechanical properties and plasma etching resistance of the photocurable composition, the added amount of the monofunctional monomer of the present application should not exceed 30% of the total mass of the photocurable composition.

[0035] Furthermore, the multifunctional monomer has at least three reactive (meth)acrylate groups. Preferably, the multifunctional monomer is one or more of tri(meth)acrylate, tetra(meth)acrylate, or a (meth)acrylate with higher functionality. Such multifunctional monomers can act as crosslinking agents to increase the crosslinking density of the photocurable composition.

[0036] Furthermore, the photoinitiator includes any typical photo-free radical initiator capable of initiating a photocuring reaction, specifically including one or more of a triazine initiator, an acetophenone initiator, a benzophenone initiator, a thiophenone initiator, a benzoin initiator, a phosphorus initiator, and an oxime initiator. Preferably, the photoinitiator used in this application is a phosphorus initiator having a maximum absorption wavelength of 360nm to 400nm, wherein the phosphorus initiator can advantageously initiate photocuring of the photocurable composition when irradiated with long-wavelength ultraviolet light. In addition, the amount of the photoinitiator added accounts for 1 to 10% of the total mass of the photocurable composition. Within this range, under the irradiation of ultraviolet light, the photocurable composition can fully undergo photopolymerization and can prevent the transmittance from being reduced due to the remaining unreacted photoinitiator after photopolymerization.

[0037] The photocurable composition of the present application is prepared by adding component (A) a silicon-based photocurable monofunctional monomer, component (B) a silicon-based photocurable difunctional monomer, component (C) a non-silicon-based photocurable monomer, and component (D) a photoinitiator in the aforementioned proportions to a brown light-proof bottle and mixing until uniform, thereby obtaining the photocurable composition. Furthermore, the photocurable composition of the present application does not contain any solvent, i.e., it is a solvent-free photocurable composition.

[0038] In summary, the present application provides an encapsulation structure comprising an organic barrier layer and an inorganic barrier layer, wherein the organic barrier layer contacts an organic light-emitting diode (OLED) and the inorganic barrier layer is laminated and disposed above the organic barrier layer. The organic barrier layer is formed from the aforementioned photocurable composition. The organic barrier layer generates less than 10 ppm of outgassing, ensuring minimal impurity release from the organic barrier layer during the deposition of the inorganic barrier layer and ensuring high flatness of the organic layer, thereby achieving effective encapsulation of the OLED.

[0039] Specifically, the organic barrier layer can be printed with a thickness of 1 μm to 15 μm by inkjet printing, and the thickness of the organic barrier layer can be printed with a thickness of 1 μm to 15 μm by 10 mW / cm 2 Up to 500mW / cm 2The photocurable composition is cured by irradiating with ultraviolet light for 1 to 100 seconds. The photocurable composition of the present application has a viscosity of 15 to 45 cps at 25°C and a surface tension of 20 to 38 mN / m, exhibiting good inkjet printing performance. The photocurable composition may further include typical additives known in the art, such as heat stabilizers, antioxidants, and ultraviolet light absorbers, which will not be described in detail.

[0040] The organic barrier layer formed in this application can achieve excellent plasma resistance. After actual testing, its plasma etching rate is below 7%, and it has low roughness to ensure excellent quality. At the same time, it has lower water vapor permeability. After actual testing, its water vapor permeability is 3.0g / m 2 24 hours or less. This prevents corrosion and degradation of OLED luminous efficiency caused by external moisture and / or oxygen penetration, improving the reliability of OLEDs during operation. Furthermore, the barrier layer has a photocuring rate exceeding 96% and a glass transition temperature exceeding 100°C. These properties fully meet operational requirements in terms of heat resistance, chemical resistance, dimensional stability, and long-term reliability, effectively encapsulating OLEDs.

[0041] The inorganic barrier layer of the present invention is formed of the same or different inorganic materials, and can be formed by sputtering, chemical vapor deposition, atomic layer deposition, particle beam assisted deposition of metal oxides and nitrides; specifically, the inorganic material of the inorganic barrier layer includes silicon oxide (SiO X ), silicon nitride (SiN x ), silicon oxynitride (SiO x N y ), ZnSe, ZnO, Sb2O3, Al2O3, etc., wherein x and y are in the range of 1 to 5, preferably, the thickness of the inorganic barrier layer is 1 to 1000 nm.

[0042] Compared with the prior art, this application has the following beneficial effects:

[0043] A packaging structure for encapsulating an organic light-emitting diode (OLED), comprising only two layers: an organic barrier layer and an inorganic barrier layer. This structure meets the development needs of organic light-emitting devices towards light weight, thin thickness, and low cost. Furthermore, the organic barrier layer formed by irradiating a photocurable composition with ultraviolet light provided herein has a lower plasma etching rate, lower water vapor permeability, and lower impurity gas release than those in the prior art. Furthermore, it also has a higher photocuring rate and a higher glass transition temperature. Therefore, even with a two-layer packaging structure, a stable and reliable packaging effect can be achieved, protecting the functional structures within the OLED from corrosion by water vapor and oxygen, thereby improving the reliability and service life of the OLED device and meeting the stringent requirements for the functional characteristics and packaging effect of OLED packaging materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings are incorporated into and constitute a part of this specification and, together with the description, are used to explain the principles of the present invention.

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0046] FIG1 is a cross-sectional view of an organic light emitting diode device of the present application.

[0047] Among them: 1 is the base substrate; 2 is the organic light emitting diode; 3 is the organic barrier layer; 4 is the inorganic barrier layer. DETAILED DESCRIPTION

[0048] Here, exemplary embodiments will be described in detail, and the embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are only examples of devices consistent with some aspects of the present application as detailed in the appended claims.

[0049] In order to enable those skilled in the art to better understand the technical solution of the present application, the present application is further described in detail below in conjunction with embodiments.

[0050] Synthesis Example 1 (Target Product Formula 1-1 Compound)

[0051] 500 mL of ethyl acetate, 50 g of methyl (diphenyl) silane and 80 g of allyl alcohol were added to the reactor, which was then replaced with nitrogen three times. 144 ppm of platinum-carbon black catalyst was added to the reactor, heated to 80 ° C and stirred for 4 hours, and the remaining solvent was distilled off to obtain an intermediate product. Then, 130 g of the obtained intermediate product and 32 g of triethylamine were added to 500 methylene chloride, cooled to 0 ° C, 30 g of methacryloyl chloride was slowly added, and the solvent was distilled off to obtain a compound represented by Formula 1-1.

[0052] Synthesis Example 2 (Target Product Formula 1-2 Compound)

[0053] 500 mL of dichloromethane, 50 g of 2-hydroxyethyl methacrylate and 43.7 g of triethylamine were added to the reactor, and then 87.4 g of triphenylsilyl chloride was slowly added while stirring these components at 0°C, and then heated to 25°C and stirred for 4 hours, and the remaining solvent was distilled off to obtain the compound represented by Formula 1-2.

[0054] Synthesis Example 3 (Target Product Formula 2-1 Compound)

[0055] 600 mL of ethyl acetate, 66.4 g of 3,3-diphenyl-1,1,5,5-tetramethyltrisiloxane (Beijing Bailingwei Technology Co., Ltd.), and 46.5 g of allyl alcohol were added to a reaction vessel, purged with nitrogen, and replaced three times. 200 ppm of platinum / carbon black powder was added to the mixture, heated to 80°C, stirred for 4 hours, and the solvent was distilled off. The obtained compound and 60.7 g of triethylamine were added to 400 ml of dichloromethane, and then 50.2 g of methacryloyl chloride was slowly added. At the same time, the composition was stirred at 0°C, the solvent was distilled off, and the compound represented by formula 2-1 was obtained by column separation.

[0056] Synthesis Example 4 (Target Product Formula 2-2 Compound)

[0057] 600 mL of ethyl acetate, 54.1 g of 3-phenyl-1,1,3,5,5-pentamethyltrisiloxane (Beijing Bailingwei Technology Co., Ltd.), and 46.5 g of allyl alcohol were added to a reaction vessel, and nitrogen was passed through and replaced three times. 200 ppm of platinum / carbon black powder was added to the mixture, and the mixture was heated to 80°C and stirred for 4 hours. The solvent was distilled off, and the obtained compound and 60.7 g of triethylamine were added to 400 ml of dichloromethane, and then 43.5 g of acryloyl chloride was slowly added. At the same time, the composition was stirred at 0°C, the solvent was distilled off, and the compound represented by formula 2-2 was obtained by column separation.

[0058] Synthesis Example 5 (Target Product Formula 2-4 Compound)

[0059] In a 1000 ml flask equipped with a cooling tube and a stirrer, 300 ml of ethyl acetate, 18 g of 1,1,3,3,5,5-hexamethyltrisiloxane, and 40 g of allyl alcohol were placed, and then purged with nitrogen for 30 minutes. Next, 72 ppm of Custer catalyst was added, and the flask was heated to 80°C and the components were stirred for 4 hours. The remaining solvent was removed by distillation to obtain the obtained compound. 68.4 g of the obtained compound and 37 g of triethylamine were added sequentially to 300 ml of dichloromethane, and then 29.1 g of methacryloyl chloride was slowly added to the mixture while slowly stirring it at 0°C. The remaining solvent was removed by distillation to obtain the target product represented by Formula 2-4.

[0060] The detailed information of the components used in Examples and Comparative Examples are as follows:

[0061] (A) Silicon-based photocurable monofunctional monomer: (A1) a monomer represented by Formula 1-1 (Synthesis Example 1), (A2) a monomer represented by Formula 1-2 (Synthesis Example 2);

[0062] (B) Silicon-based photocurable bifunctional monomer: (B1) a monomer represented by Formula 2-1 (Synthesis Example 3); (B2) a monomer represented by Formula 2-2 (Synthesis Example 4); (B3) a monomer represented by Formula 2-4 (Synthesis Example 5);

[0063] (C) Non-silicon-based photocurable monomers: (C1) isobornyl methacrylate; (C2) 2-phenoxyethyl methacrylate; (C3) dodecyl methacrylate; (C4) pentaerythritol tetraacrylate;

[0064] (D) Photoinitiator: photoinitiator TPO.

[0065] Example 1

[0066] As shown in FIG1 , this example provides a packaging structure for encapsulating an organic light-emitting diode, including an organic light-emitting diode 2 disposed on a base substrate 1. The packaging structure is disposed on the organic light-emitting diode 2 and, in combination with the base substrate 1, covers the entire organic light-emitting diode 2. The packaging structure is composed of an organic barrier layer 3 and an inorganic barrier layer 4, wherein the organic barrier layer 3 contacts the organic light-emitting diode 2, and the inorganic barrier layer 4 is laminated on top of the organic barrier layer 3.

[0067] The organic barrier layer 3 is formed from a photocurable composition. Specifically, in parts by weight, the photocurable composition in this embodiment comprises 15 parts by weight of A1, 40 parts by weight of B1, 10 parts by weight of C1, 15 parts by weight of C3, 15 parts by weight of C4, and 5 parts by weight of D. The composition is placed in a 125 mL brown bottle and then mixed using an oscillator for 3 hours to prepare the photocurable composition.

[0068] Example 2

[0069] As shown in FIG1 , this example provides a packaging structure for encapsulating an organic light-emitting diode, including an organic light-emitting diode 2 disposed on a base substrate 1. The packaging structure is disposed on the organic light-emitting diode 2 and, in combination with the base substrate 1, covers the entire organic light-emitting diode 2. The packaging structure is composed of an organic barrier layer 3 and an inorganic barrier layer 4, wherein the organic barrier layer 3 contacts the organic light-emitting diode 2, and the inorganic barrier layer 4 is laminated on top of the organic barrier layer 3.

[0070] The organic barrier layer 3 is formed from a photocurable composition. Specifically, in parts by weight, the photocurable composition in this embodiment comprises 20 parts by weight of A1, 35 parts by weight of B1, 10 parts by weight of C2, 15 parts by weight of C3, 15 parts by weight of C4, and 5 parts by weight of D. The components are placed in a 125 mL brown bottle and then mixed using an oscillator for 3 hours to prepare the photocurable composition.

[0071] Example 3

[0072] As shown in FIG1 , this example provides a packaging structure for encapsulating an organic light-emitting diode, including an organic light-emitting diode 2 disposed on a base substrate 1. The packaging structure is disposed on the organic light-emitting diode 2 and, in combination with the base substrate 1, covers the entire organic light-emitting diode 2. The packaging structure is composed of an organic barrier layer 3 and an inorganic barrier layer 4, wherein the organic barrier layer 3 contacts the organic light-emitting diode 2, and the inorganic barrier layer 4 is laminated on top of the organic barrier layer 3.

[0073] The organic barrier layer 3 is formed from a photocurable composition. Specifically, in parts by weight, the photocurable composition in this embodiment includes 5 parts by weight of A2, 50 parts by weight of B2, 15 parts by weight of C1, 5 parts by weight of C3, 20 parts by weight of C4, and 5 parts by weight of D. The composition is placed in a 125 mL brown bottle and then mixed using an oscillator for 3 hours to prepare the photocurable composition.

[0074] Example 4

[0075] As shown in FIG1 , this example provides a packaging structure for encapsulating an organic light-emitting diode, including an organic light-emitting diode 2 disposed on a base substrate 1. The packaging structure is disposed on the organic light-emitting diode 2 and, in combination with the base substrate 1, covers the entire organic light-emitting diode 2. The packaging structure is composed of an organic barrier layer 3 and an inorganic barrier layer 4, wherein the organic barrier layer 3 contacts the organic light-emitting diode 2, and the inorganic barrier layer 4 is laminated on top of the organic barrier layer 3.

[0076] The organic barrier layer 3 is formed from a photocurable composition. Specifically, in parts by weight, the photocurable composition in this embodiment comprises 15 parts by weight of A2, 40 parts by weight of B2, 10 parts by weight of C1, 10 parts by weight of C2, 5 parts by weight of C3, 5 parts by weight of C4, and 5 parts by weight of D. The composition is placed in a 125 mL brown bottle and then mixed using an oscillator for 3 hours to prepare the photocurable composition.

[0077] Comparative Example 1

[0078] The specific implementation of Comparative Example 1 is different from that of Example 1 only in that the silicon-based photocurable bifunctional monomer B used in Comparative Example 1 is 40 parts by weight of B3, and the other components and proportioning conditions are exactly the same.

[0079] Comparative Example 2

[0080] The specific implementation of Comparative Example 2 is different from that of Example 1 only in that the silicon-based photocurable bifunctional monomer B used in Comparative Example 2 is 55 parts by weight of B1, and the other components and proportioning conditions are exactly the same.

[0081] Comparative Example 3

[0082] The specific implementation of Comparative Example 3 is different from that of Example 1 only in that the non-silicon-based photocurable monomer C used in Comparative Example 3 is only 30 parts by weight of C3 and 10 parts by weight of C4, and the other components and proportioning conditions are exactly the same.

[0083] In order to further verify the efficacy of the present application, the inventors conducted the following relevant tests on the organic barrier layers (photocurable compositions) obtained in Examples 1 to 4 and Comparative Examples 1 to 3:

[0084] Performance testing:

[0085] (1) Outgassing: The photocurable composition was inkjet printed on a glass substrate and the photocurable composition was sprayed with a 150 mJ / cm 2The sample was UV-cured for 30 seconds under UV irradiation, and the cured sample was peeled off and cut into thin strips (8 mm × 55 mm). The strips were attached to the inner wall of a 20 mL empty head bottle. The sample weighed about 0.1 g. Outgas was measured using a gas chromatography-mass spectrometer (Thermo Fisher TRACE1300). The gas chromatography-mass spectrometry instrument used an Agilent HP-5MS UI column (length: 30 m, diameter: 0.25 mm, stationary phase thickness: 0.25 μm) as a chromatographic column, and helium was used as a mobile phase with a split ratio of 17:1. The temperature program was set as follows: 35°C for 2 min, increased to 200°C at 8°C / min, increased to 300°C at 20°C / min, and maintained for 10 min. The degassing was collected under the following conditions: the collection temperature was 110°C, the collection time was 30 min, and He gas was purged at a flow rate of 200 mL / min. The adsorbent was 5% phenylmethylpolysiloxane, and NMP solutions of acetone with concentrations of 6 ppm, 8 ppm, 10 ppm, 12 ppm, and 14 ppm were used as standard solutions to draw a calibration curve, where R 2 The value is 0.9991.

[0086] (2) Plasma Etching Rate: The composition for OLED thin film encapsulation was coated onto a silicon wafer and photocured to form an organic layer, and then the initial coating height of the organic layer (T1, unit: μm) was measured. The organic barrier layer was plasma treated under the following conditions: ICP power: 2500 W; RE power: 300 W; DC bias: 200 V; Ar flow rate: 50 sccm; etching time: 1 minute; pressure: 10 mTorr, and then the height of the organic layer (T2, unit: μm) was measured. The plasma etching rate of the organic layer was calculated by the following equation:

[0087] Plasma etching rate (%) = (T1-T2) / T1×100%

[0088] Here, T1 is the initial height of the organic layer, and T2 is the height of the organic layer after plasma treatment.

[0089] (3) Photocuring rate: FT-IR (Bruker INVENIO) was used to measure the photocuring rate of the glue before curing and the film after curing at 1635 cm -1 (C=C) and 1720cm -1 Absorption peak intensity near (C=O). Curing rate (%) = |1-(C1 / C0)| × 100%;

[0090] Among them, C1 is the cured film at 1635cm -1 The absorption peak intensity near 1720 cm -1 The ratio of the absorption peak intensities near 1635cm -1The absorption peak intensity near 1720 cm -1 The ratio of the absorption peak intensities near

[0091] (4) Glass transition temperature (Tg): The prepared photocurable composition was inkjet printed on a glass substrate and heated to 30 mW / cm 2 A sample with a size of 5 cm × 5 cm × 1 mm (width × length × thickness) was prepared by subjecting it to UV curing for 60 s under UV irradiation. The sample was then tested using a differential scanning calorimeter (DSC). The test conditions were: test atmosphere N2 / O2; test temperature range: -180 to 550°C; heating rate: 10°C / min.

[0092] (5) Water vapor transmission rate: The prepared photocurable composition was inkjet printed on a glass substrate and the water vapor transmission rate was 30 mW / cm 2 A specimen having a size of 5 cm×5 cm×1 mm (width×length×thickness) was prepared by subjecting it to UV curing for 60 s by UV irradiation under UV conditions, and then the water vapor transmission rate was measured using a water vapor transmission rate tester (PERMATRAN-W3 / 33, manufactured by MOCON) at 85° C. and 85% relative humidity for 24 hours.

[0093] (6) Film thickness uniformity: The film was coated on a 6-inch ordinary glass at a speed of 500 r / min on a coating machine. The spin-coated film was irradiated under a UV lamp for 30 seconds, and then 30 points were evenly selected on an ellipsometer to measure the film thickness. After measuring the thickness of 30 points, the film thickness uniformity was calculated using the following formula.

[0094] Film thickness uniformity = (maximum film thickness - minimum film thickness) / (maximum film thickness + minimum film thickness) * 100%;

[0095] (7) Leveling characteristics: Print one drop on an inkjet printer, and observe the droplet leveling diameter (μm) after leveling for 120 s;

[0096] Performance test results: as shown in Table 1 below:

[0097] Table 1

[0098] The data in Table 1 show that the properties of the cured film layer (organic barrier layer) obtained by using the photocurable composition of the present application are as follows: degassing generation <5ppm, plasma etching rate <7%, photocuring rate >97, glass transition temperature ≥103°C, water vapor transmission rate <3g / m 2After 24 hours, the film thickness uniformity is less than 3.2%, and the leveling properties are maintained in the range of 180μm to 260μm. That is, the organic barrier layer obtained in this application has excellent properties. Therefore, the two-layer packaging structure composed of the organic barrier layer and the inorganic barrier layer not only has the advantages of light weight, thin thickness and low cost, but also has a lower plasma etching rate, lower water vapor permeability and lower impurity gas release. At the same time, it has a high photocuring rate and a high glass transition temperature. Therefore, the use of this packaging structure can significantly improve the reliability and service life of OLED devices.

[0099] The foregoing description is merely a detailed description of the present invention, intended to enable those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0100] It should be understood that the present application is not limited to the above-described contents, and various modifications and changes can be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A packaging structure for packaging an organic light emitting diode, characterized in that: The encapsulation structure is composed of two layers, an organic barrier layer (3) and an inorganic barrier layer (4); the organic barrier layer (3) is formed of a photocurable composition, and the degassing amount of the organic barrier layer (3) is less than 10 ppm, and the plasma etching rate is less than 7%; The organic barrier layer (3) is in contact with the organic light-emitting diode (2), and the inorganic barrier layer (4) is arranged on top of the organic barrier layer (3).

2. The packaging structure of an organic light emitting diode according to claim 1, characterized in that: The photocurable composition comprises the following components (A) to (D): (A) component: a silicon-based photocurable monofunctional monomer, (B) component: a silicon-based photocurable bifunctional monomer, (C) component: a non-silicon-based photocurable monomer, (D) ingredient: photoinitiator; The photocurable composition comprises, by weight, 5 to 20 parts of a silicon-based photocurable monofunctional monomer, 30 to 50 parts of a silicon-based photocurable difunctional monomer, 20 to 60 parts of a non-silicon-based photocurable monomer and 1 to 10 parts of a photoinitiator.

3. The encapsulation structure for encapsulating an organic light emitting diode according to claim 2, characterized in that: The silicon-based photocurable monofunctional monomer is represented by structural formula (1): In the structural formula (1), R1, R2, and R3 are each independently any one of a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C1-C20 alkoxy group, a substituted or unsubstituted C3-C20 cycloalkyl group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C3-C30 heteroaryl group, and a substituted or unsubstituted C7-C30 aralkyl group; X is a single bond, O, S, NH or NR', wherein R' is any one of a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C3-C10 cycloalkyl group, and a substituted or unsubstituted C1-C10 aryl group; Y is any one of a substituted or unsubstituted C1-C20 alkylene group, a substituted or unsubstituted C1-C20 alkyleneoxy group, a substituted or unsubstituted C3-C20 cycloalkylene group, and a substituted or unsubstituted C6-C30 arylene group; R4 is hydrogen or methyl.

4. The encapsulation structure for encapsulating an organic light emitting diode according to claim 2 is characterized in that: The silicon-based photocurable bifunctional monomer is represented by structural formula (2): In the structural formula (2), Y1, Y2, Y3, Y4, Y5, and Y6 are each independently hydrogen, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C1-C20 alkoxy, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, or substituted or unsubstituted C7-C30 aralkyl; Y7 and Y8 are each independently any one of a single bond, a substituted or unsubstituted C1-C20 alkylene group, a substituted or unsubstituted C1-C20 alkyleneoxy group, a substituted or unsubstituted C6-C30 arylene group, and a substituted or unsubstituted C7-C30 arylalkylene group; Y9 and Y10 are each independently hydrogen or methyl.

5. The encapsulation structure for encapsulating an organic light emitting diode according to claim 2, characterized in that: The non-silicon-based photocurable monomer is a mixture of a monofunctional monomer and a multifunctional monomer, and the weight ratio of the monofunctional monomer and the multifunctional monomer is (1:0.1) to (1:10).

6. The encapsulation structure for encapsulating an organic light emitting diode according to claim 5, characterized in that: The monofunctional monomer is a mixture of at least two mono(meth)acrylate monomers.

7. The encapsulation structure for encapsulating an organic light emitting diode according to claim 6, characterized in that: The mono(meth)acrylate monomer is a cyclic mono(meth)acrylate and / or an aliphatic mono(meth)acrylate.

8. The encapsulation structure for encapsulating an organic light emitting diode according to claim 5, characterized in that: The multifunctional monomer has at least three reactive (meth)acrylate groups.

9. The encapsulation structure for encapsulating an organic light emitting diode according to claim 8, characterized in that: The multifunctional monomer is one or more of tri(meth)acrylate, tetra(meth)acrylate or (meth)acrylate with higher functionality.

10. The encapsulation structure for encapsulating an organic light emitting diode according to claim 2, characterized in that: The photoinitiator includes one or more of triazine initiator, acetophenone initiator, benzophenone initiator, thiophenone initiator, benzoin initiator, phosphorus initiator and oxime initiator.

11. The encapsulation structure for encapsulating an organic light emitting diode according to claim 5, characterized in that: The added amount of the monofunctional monomer does not exceed 30% of the total mass of the photocurable composition.

12. The encapsulation structure for encapsulating an organic light emitting diode according to claim 7, characterized in that: The viscosity of the cyclic mono(meth)acrylate is ≤15 cps at 25°C.

13. The packaging structure for packaging an organic light emitting diode according to claim 2, characterized in that: The added amount of the photoinitiator accounts for 1-10% of the total mass of the photocurable composition.

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