OLED Display Black Matrix for Flexibility and Reflectivity
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Solution Overview
Problem
Existing OLED display devices face challenges in bending due to thick polarizers, which cause light loss and reduced display brightness, and are prone to moisture absorption and adhesion issues with polyvinyl alcohol films.
Innovation Solution
The OLED display device employs a black matrix with alternating first and second black matrix layers of different thicknesses, replacing the traditional polarizer, and includes an optical film with a protective and adhesive layer, using materials like polyimide, cyclic olefins polymer, or polyethylene glycol terephthalate, to enhance flexibility and reduce reflectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a thick polarizer is used to prevent ambient light reflection, then display quality is improved, but light loss increases and display brightness decreases
Solution Approach 1:
The patent changes the optical parameters of the optical film by introducing a negative optical path difference (NP) design. The optical film is configured with a thickness and refractive index that create a negative optical path difference to compensate for the phase difference introduced by the polarizer, thereby reducing reflectivity without requiring a thick polarizer. This resolves the contradiction by achieving anti-reflection through parameter optimization rather than increasing polarizer thickness.
Solution Approach 2:
The patent uses a composite structure consisting of an optical film with specific material properties (negative optical path difference) combined with the polarizer layer. The optical film is made of materials with controlled refractive indices and thicknesses that work together with the polarizer to reduce reflectivity while minimizing light loss. This composite approach allows the system to achieve both anti-reflection and high brightness simultaneously.
2Object-affected harmful factors
If a thick polarizer is used to ensure display quality, then ambient light reflection is reduced, but the OLED display panel becomes difficult to bend
Solution Approach 1:
The patent optimizes the thickness parameter of the optical film to create a negative optical path difference that compensates for polarizer-induced reflectivity without requiring excessive polarizer thickness. By precisely controlling the optical film thickness (typically 50-200 nm) and refractive index, the system achieves anti-reflection properties while maintaining the flexibility needed for bending applications.
Solution Approach 2:
The patent introduces a thin optical film layer (much thinner than traditional polarizer thickness) that provides the necessary optical compensation. This thin-film approach maintains the flexibility and bendability of the OLED display panel while still achieving the desired anti-reflection effect through its negative optical path difference design.
3Object-affected harmful factors
If a polyvinyl alcohol film is used as the polarizer material, then polarizing function is achieved, but moisture absorption and warpage problems occur
Solution Approach 1:
The patent combines the polarizer layer with an optical film made of moisture-resistant materials. The optical film serves as both an optical compensation element and a protective barrier against moisture. This composite structure allows the use of polyvinyl alcohol polarizer material while mitigating its moisture absorption issues through the protective optical film layer.
Solution Approach 2:
The optical film acts as an intermediary layer between the polarizer and the external environment. It provides optical compensation for the polarizer's reflectivity while simultaneously serving as a protective barrier that prevents moisture from reaching the polyvinyl alcohol polarizer material, thereby preventing warpage and maintaining reliability.
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
This solution simplifies the OLED display device structure, allows for easier bending, and reduces reflectivity while maintaining adequate light transmission and brightness by using a black matrix with varying thicknesses instead of a thick polarizer.
Implementation Method 1
the black matrix layer includes a plurality of first black matrix layers and a plurality of second black matrix layers... each of the first black matrix layers and each of the second black matrix layers are formed via photoetching and high temperature curing
Implementation Method 2
The optical film includes an optical film body layer, a black matrix layer, a protective layer, and an adhesive layer which are disposed layer by layer, where the optical film is attached to the OLED display panel through the adhesive layer
Data Source
AI summary
An organic light emitting diode (OLED) display device includes an OLED display panel, where a surface of the OLED display panel includes a plurality of pixel display units and a plurality of non-pixel display units; an optical film including an optical film body layer, a black matrix layer, a protective layer, and an adhesive layer which are disposed layer by layer, where the black matrix layer includes a plurality of first black matrix layers and a plurality of second black matrix layers, each of the first black matrix layers is alternated with each of the second black matrix layers.