Glass Substrate Sealing Material Layer for OLED Reliability
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Solution Overview
Problem
Current methods for sealing OLED displays using organic resin-based bonding materials fail to maintain air tightness due to gas penetration, leading to degradation of the organic light-emitting layer and reliability issues, while glass powder sealing methods damage active elements and organic materials due to high heat requirements.
Innovation Solution
A glass substrate with a sealing material layer comprising inorganic powder, specifically glass powder and refractory filler, with controlled refractory filler content and surface smoothness, is used for laser sealing, which reduces thermal expansion, enhances mechanical strength, and prevents gas release, thereby improving long-term reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass powder sealing material is used to achieve excellent water resistance and air tightness, then sealing performance is improved, but thermal degradation of active elements and organic light-emitting materials occurs due to high softening point requiring furnace heating
Solution Approach 1:
The patent changes the physical and chemical parameters of the sealing material by incorporating organic resin components with low softening points (below 150°C) alongside glass powder. This parameter modification enables the sealing material to soften and seal at low temperatures, preventing thermal degradation of heat-sensitive components while maintaining the water resistance and air tightness provided by the glass powder.
Solution Approach 2:
The patent creates a composite sealing material combining glass powder (for water resistance and air tightness) with organic resin components (for low-temperature softening). This composite structure allows the sealing material to exhibit both the sealing performance of glass and the low-temperature processability of organic resins, resolving the contradiction between sealing quality and thermal compatibility.
2Ease of manufacture
If organic resin-based bonding material is used to bond glass substrates at low temperature, then ease of manufacture is improved, but gas penetration occurs leading to degradation of organic light-emitting layer
Solution Approach 1:
The patent develops a composite bonding material combining organic resin components (for low-temperature bonding) with glass powder particles (for gas blocking). This composite structure enables the material to bond glass substrates at low temperatures while the glass powder particles create a physical barrier that prevents gas penetration, thus achieving both ease of manufacture and reliability.
Solution Approach 2:
The patent applies local quality by incorporating glass powder particles specifically into the bonding material at the sealing interface, where gas blocking is most critical. This localized enhancement of gas barrier properties within the bonding material ensures effective sealing without requiring the entire organic resin structure to provide gas resistance.
3Reliability
If conventional sealing methods are used to ensure hermetic sealing, then sealing quality is improved, but thermal expansion differences cause stress and cracking
Solution Approach 1:
The patent modifies the thermal expansion parameters of the sealing material by selecting glass powder with specific composition and incorporating organic resin components. This parameter adjustment enables the sealing material's thermal expansion coefficient to closely match that of the glass substrate, reducing thermal expansion differences and preventing stress and cracking during temperature cycling while maintaining hermetic sealing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively seals OLED displays with a low-power laser, preventing thermal degradation and maintaining air tightness without the need for additional gas adsorption materials, thus enhancing the long-term reliability of OLED devices.
Implementation Method 1
laser sealing can locally heat only the sites that should be sealed, and hence glass substrates can be sealed with each other while thermal degradation of an active element and the like is prevented
Implementation Method 2
it has been necessary to put the whole OLED display in an electric furnace and fire it at a temperature equal to or higher than the softening temperature of the glass powder, thereby softening and flowing the glass powder
Data Source
AI summary
Provided is a glass substrate with a sealing material layer, including a sealing material layer formed by sintering a sealing material, in which: the sealing material includes at least inorganic powder; the inorganic powder includes glass powder and a refractory filler; the content of refractory filler in the inorganic powder is 10 to 35 vol %; and the sealing material layer has a surface roughness Ra of less than 0.5 μm.