Glass substrate for flexible OLED display

Abstract

The invention discloses a glass substrate for flexible OLED display, and belongs to the technical field of electronic information display. Comprising the following raw materials in percentage by mass: 58 to 62 percent of SiO2, 18 to 22 percent of Al2O3, 1.5 to 3 percent of B2O3, 3 to 4 percent of MgO, 3.5 to 4.5 percent of CaO, 6 to 8 percent of SrO, 0.15 to 0.25 percent of SnO, 0.8 to 1.50 percent of La2O3 and 0.35 to 0.45 percent of Y2O3. SnO is added and can be used as a clarifying agent, so that the transparency of the glass is improved; through co-doping of rare earth elements La2O3 and Y2O3, the transmittance of ultraviolet light can be greatly improved; therefore, the prepared glass substrate is endowed with higher elastic modulus, strain point and ultraviolet light transmittance and lower thermal shrinkage rate by accurately regulating and controlling the dosage of each component, and has important application value in the technical field of electronic information display.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic information display, and in particular, relates to a glass substrate for flexible OLED display. Background Art

[0002] The main difference between flexible OLED and traditional TFT-LCD and hard screen OLED is that, first of all, the process of flexible OLED begins with coating and curing high temperature resistant plastic materials such as polyimide on the glass substrate, then using multi-layer film (not glass) to encapsulate the flexible display, and finally the plastic substrate needs to be peeled off from the glass substrate. Although glass plays a completely different role in these processes, they are all very important. For flexible OLED displays, high-performance display glass is used as a substrate in the panel process. It will be cut into half or a quarter of the original size of the substrate before the OLED deposition process, and finally the plastic substrate is peeled off from the glass substrate using ultraviolet light. The glass substrate must use a high-performance display glass substrate with a pure surface, excellent dimensional stability and optical properties to carry out these two processes. Therefore, the transmittance of ultraviolet light is very important (generally 308nm ultraviolet transmittance is used as the evaluation standard). In addition, flexible OLED panels put forward some new requirements for the performance of glass substrates. For example, they can withstand smaller curvature radius requirements without cracking when bending, and large-size substrates have as little sag as possible during transmission. This requires improving the requirements for the mechanical properties of the glass substrate. At the same time, the thermal shrinkage rate is the amount of shrinkage and deformation of the glass substrate after high-temperature heat treatment at 550℃-600℃. The smaller the thermal shrinkage rate, the higher the quality and production efficiency of the high-precision panel. Therefore, it is urgent to invent a flexible OLED substrate glass with small thermal shrinkage, high mechanical properties and good ultraviolet light transmittance to meet the higher demands in the field of electronic information display technology. Summary of the invention

[0003] The purpose of the present invention is to overcome the defects of the prior art and provide a glass substrate for a flexible OLED display.

[0004] The purpose of the present invention can be achieved through the following technical solutions: A glass substrate for a flexible OLED display comprises the following raw materials in percentage by mass: 58-62% SiO2, 18-22% Al2O3, 1.5-3% B2O3, 3-4% MgO, 3.5-4.5% CaO, 6-8% SrO, 0.15-0.25% SnO, 0.8-1.50% La2O3 and 0.35-0.45% Y2O3.

[0005] Furthermore, the mass percentage of (MgO+CaO+SrO) in the glass substrate is 14-17%.

[0006] Furthermore, the mass ratio of MgO to (MgO+CaO+SrO) is 0.20-0.30; and the mass ratio of MgO to SrO is 0.45-0.55.

[0007] Furthermore, the mass ratio of SnO to Y2O3 is 0.40-0.55.

[0008] Furthermore, the mass ratio of La2O3 to Y2O3 is 2.5-4.

[0009] A glass substrate for a flexible OLED display is prepared by the following steps: S1. Add SiO2, Al2O3, B2O3, MgO, CaO, SrO, SnO, La2O3 and Y2O3 into a mixer, mix and stir evenly to obtain a mixture; S2, adding the mixture obtained in step S1 into a tubular furnace, raising the temperature from room temperature to 1550°C at a rate of 2.5°C / min, and keeping the temperature for 2 hours, then raising the temperature from 1550°C to 1700°C at a rate of 2°C / min, and keeping the temperature for 6 hours, to obtain glass liquid; S3, pouring the glass liquid obtained in step S2 onto a copper plate for molding and annealing to obtain a glass substrate for flexible OLED display.

[0010] Furthermore, the annealing condition is at 700-800° C. and kept warm for 4-8 hours.

[0011] Beneficial effects of the present invention: 1. The glass substrate prepared by the present invention is aluminosilicate glass, which ensures that the strength and toughness of the obtained flexible glass are higher than those of ordinary silicate glass; 2. Adding MgO can not only improve the chemical stability of glass and reduce viscosity, but also improve the heat resistance of glass; 3. Adding SrO can increase the expansion coefficient of glass and improve chemical stability; 4. Adding SnO can be used as a glass clarifier to help remove bubbles in the glass melt and improve the transparency and uniformity of the glass; 5. The transmittance of ultraviolet light can be greatly improved by co-doping rare earth elements La2O3 and Y2O3; Therefore, the glass substrate prepared by the present invention has a higher elastic modulus, a higher strain point, a lower thermal shrinkage rate, and a higher ultraviolet light transmittance by precisely controlling the amount of each component, and has important application value in the field of electronic information display technology. DETAILED DESCRIPTION

[0012] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0013] A glass substrate for a flexible OLED display is prepared by the following steps: S1. Add the glass batch material into a mixer, mix and stir evenly to obtain a mixture; S2, adding the mixture obtained in step S1 into a tubular furnace, raising the temperature from room temperature to 1550°C at a rate of 2.5°C / min, and keeping the temperature for 2 hours, then raising the temperature from 1550°C to 1700°C at a rate of 2°C / min, and keeping the temperature for 6 hours, to obtain glass liquid; S3, pouring the glass liquid obtained in step S2 onto a copper plate for molding and annealing to obtain a glass substrate for flexible OLED display.

[0014] The annealing condition is 700-800°C for 4-8h; The glass batch material comprises the following raw materials in percentage by mass: 58-62% SiO2, 18-22% Al2O3, 1.5-3% B2O3, 3-4% MgO, 3.5-4.5% CaO, 6-8% SrO, 0.15-0.25% SnO, 0.8-1.50% La2O3 and 0.35-0.45% Y2O3; wherein the mass percentage of (MgO+CaO+SrO) to the glass substrate is 14-17%; wherein the mass ratio of MgO to (MgO+CaO+SrO) is 0.20-0.30; and the mass ratio of MgO to SrO is 0.45-0.55; wherein the mass ratio of SnO to Y2O3 is 0.40-0.55; and wherein the mass ratio of La2O3 to Y2O3 is 2.5-4.

[0015] By following the above steps and controlling the dosage and conditions of the raw materials, Examples 1-5 and Comparative Examples were obtained, and their properties were measured according to the following standards: Refer to GBT 38711-2020 "Test method for reheating shrinkage of ultra-thin glass" and use the laser method to test the thermal shrinkage of glass in ppm; The elastic modulus of glass was measured using a glass elastic modulus tester according to ASTM C-623, and the unit is GPa; The strain point of the glass is measured using a three-point tester in accordance with ASTM C-336, and the unit is °C.

[0016] The dosage and performance test results of each component of Examples 1-5 and Comparative Examples are shown in the following table: It can be seen from the above table that the various properties of the glass substrate prepared by co-doping the rare earth elements La2O3 and Y2O3 in the embodiment of the present invention are higher than those of the control example; and by precisely controlling the amount of each component, the glass substrate is given a higher elastic modulus, a higher strain point, a lower thermal shrinkage rate, and a higher ultraviolet light transmittance, which has important application value in the field of electronic information display technology.

[0017] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0018] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A glass substrate for flexible OLED display, characterized in that: The invention comprises the following raw materials in percentage by mass: 58-62% SiO2, 18-22% Al2O3, 1.5-3% B2O3, 3-4% MgO, 3.5-4.5% CaO, 6-8% SrO, 0.15-0.25% SnO, 0.8-1.50% La2O3 and 0.35-0.45% Y2O3.

2. The glass substrate for flexible OLED display according to claim 1, characterized in that: The mass percentage of (MgO+CaO+SrO) in the glass substrate is 14-17%.

3. The glass substrate for flexible OLED display according to claim 1, characterized in that: The mass ratio of MgO to (MgO+CaO+SrO) is 0.20-0.30; and the mass ratio of MgO to SrO is 0.45-0.

55.

4. The glass substrate for flexible OLED display according to claim 1, characterized in that: The mass ratio of SnO to Y2O3 is 0.40-0.

55.

5. The glass substrate for flexible OLED display according to claim 1, characterized in that: The mass ratio of La2O3 to Y2O3 is 2.5-4.

6. The glass substrate for flexible OLED display according to claim 1, characterized in that: Prepared by the following steps: S1. Add SiO2, Al2O3, B2O3, MgO, CaO, SrO, SnO, La2O3 and Y2O3 into a mixer, mix and stir evenly to obtain a mixture; S2, adding the mixture obtained in step S1 into a tubular furnace, raising the temperature from room temperature to 1550°C at a rate of 2.5°C / min, and keeping the temperature for 2 hours, then raising the temperature from 1550°C to 1700°C at a rate of 2°C / min, and keeping the temperature for 6 hours, to obtain glass liquid; S3, pouring the glass liquid obtained in step S2 onto a copper plate for molding and annealing to obtain a glass substrate for flexible OLED display.

7. The glass substrate for flexible OLED display according to claim 1, characterized in that: The annealing condition is 700-800° C. for 4-8 hours.

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