Reflective Sealant Scattering Light in OLED Display Panels
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Solution Overview
Problem
The low light extraction efficiency of Organic Light-Emitting Diode (OLED) display devices is due to the substrate mode/waveguide mode, where light is totally reflected and cannot emerge from the optically denser medium when the incident angle exceeds the critical angle, reducing the overall light extraction efficiency.
Innovation Solution
A sealant comprising a main body material and a reflective material, such as silicon-based particles, is used to scatter light and break the total reflection condition, improving light extraction efficiency by distributing the reflective material within the sealant and arranging reflection columns in the dummy and non-light-emission regions to redirect light back into the display region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional sealant is used to bond upper and lower substrates, then the sealing function is achieved, but light extraction efficiency is reduced due to total internal reflection at the interface
Solution Approach 1:
The sealant is formulated as a composite material containing transparent resin base material mixed with reflective particles (such as TiO2, SiO2, or Al particles with 0.1-10 μm diameter). This composite structure maintains the sealing function while the reflective particles scatter light to reduce total internal reflection, thereby improving light extraction efficiency without compromising the bonding performance between substrates
Solution Approach 2:
The refractive index of the sealant is adjusted by controlling the concentration, size, and material composition of reflective particles. By optimizing these parameters, the sealant achieves a balance between maintaining adequate adhesion strength for sealing and modifying optical properties to reduce light loss through total internal reflection at the substrate interface
2Loss of energy
If the refractive index of the sealant is increased to reduce total internal reflection, then light extraction efficiency improves, but the sealing and bonding performance may be compromised
Solution Approach 1:
The sealant uses a composite formulation where reflective particles are dispersed in a transparent resin matrix. This composite structure allows independent optimization of optical properties (through particle selection) and bonding properties (through resin selection), enabling improved light extraction without sacrificing sealing performance
Solution Approach 2:
The reflective particles are distributed throughout the sealant volume rather than concentrated at specific interfaces. This uniform distribution creates local light scattering effects throughout the bonding layer, progressively reducing total internal reflection while maintaining consistent sealing and bonding properties across the entire sealant structure
3Loss of energy
If reflective particles are added to the sealant to improve light extraction, then light scattering increases, but the manufacturing complexity and material selection difficulty increase
Solution Approach 1:
The patent specifies concrete parameter ranges for reflective particles (0.1-10 μm diameter, specific material types like TiO2, SiO2, or Al) to optimize light scattering while maintaining manufacturability. These parameter specifications provide clear manufacturing guidelines that balance light extraction improvement with production feasibility, avoiding overly complex material selection
Solution Approach 2:
The patent employs conventional, readily available reflective particles and transparent resins that are already widely used in industrial applications. By selecting common materials with established supply chains and processing methods, the invention improves light extraction efficiency without introducing significant manufacturing complexity or requiring specialized materials
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 use of the reflective sealant and reflection columns enhances light extraction efficiency by scattering and redirecting light that would otherwise be totally reflected, allowing more light to emerge from the display panel, thereby improving the overall performance of OLED display devices.
Implementation Method 1
The reflective material is distributed in the main body material... the reflective material in the sealant... scatter light and break the total reflection condition
Implementation Method 2
the substrate mode/waveguide mode, where light is totally reflected and cannot emerge from the optically denser medium when the incident angle exceeds the critical angle
Data Source
AI summary
A sealant, a display panel and a display device are provided. The sealant includes: a main body material and a reflective material distributed in the main body material. In the case that the display device adopts the sealant, due to the scattering effect of the reflective material, the light incident onto the sealant is scattered by the reflective material and the light scattered by the reflective material cannot be continuously propagated along an original total reflection propagation direction, so that the light, which is originally totally reflected, emerges from the display panel, and thus the light extraction efficiency of the display panel is improved.