Coatable Grey Polarizer for Foldable Displays
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Solution Overview
Problem
Current polarizer technologies for displays, such as LCDs and OLEDs, face challenges in achieving thinner polarizers or those that can be directly coated on substrates, which is essential for realizing foldable displays, and they often require additional barrier layers that increase thickness.
Innovation Solution
A coatable grey polarizer is developed using a composition of two or more dichroic dye compounds with enhanced dichroic ratios, forming an achromatic polarizer that can be coated directly onto substrates, including a linear polarizer with specific dichroic dye compounds and a circular polarizer incorporating an achromatic quarter-wave plate, achieving a thickness of less than 2 micrometers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional polarizing films with thickness of at least 20 micrometers are used, then dimensional stability is maintained, but the polarizer thickness increases and foldable display implementation becomes difficult
Solution Approach 1:
The patent applies this principle by developing a polarizing film with thickness of 5 micrometers or less (specifically 1-3 micrometers), transforming the conventional thick rigid structure into a thin flexible film that can be bent and folded without compromising structural integrity, enabling foldable display applications
Solution Approach 2:
The patent uses composite materials by combining polyvinyl alcohol resin with dichroic dyes and crosslinking agents, creating a multi-component system where the resin provides structural framework, the dichroic dyes provide polarization function, and crosslinking agents enhance dimensional stability in the thin film structure
2Reliability
If additional barrier layers are added to maintain dimensional stability, then reliability improves, but the polarizer thickness increases
Solution Approach 1:
The patent merges the functions of multiple layers into a single integrated polarizing film structure. The crosslinked polyvinyl alcohol-dichroic dye composite simultaneously provides dimensional stability, polarization function, and mechanical strength, eliminating the need for separate barrier layers that would increase thickness
Solution Approach 2:
The patent changes the physical and chemical parameters of the polarizing film by implementing crosslinking of the polyvinyl alcohol chains, which fundamentally alters the material's dimensional stability properties, allowing thin film formation without requiring additional thick barrier layers
3Adaptability or versatility
If polarizers are made thinner for foldable displays, then adaptability improves, but manufacturing precision becomes more difficult to achieve
Solution Approach 1:
The patent applies preliminary action by pre-crosslinking the polyvinyl alcohol resin to form a stable gel structure before dyeing. This preliminary crosslinking creates a rigidified matrix that maintains uniform thickness and prevents distortion during subsequent manufacturing steps, enabling precise control of thin film dimensions
Solution Approach 2:
The patent applies local quality by creating a crosslinked gel structure throughout the polyvinyl alcohol matrix that provides localized structural reinforcement. This distributed crosslinking network maintains uniform mechanical properties and dimensional stability across the entire thin film, ensuring consistent quality throughout the polarizer
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 coatable grey polarizer effectively transmits most visible light of a specific polarization while absorbing orthogonal polarized light, providing improved thinness and uniform absorption across the visible spectrum, enhancing display performance and enabling thinner, flexible display solutions.
Implementation Method 1
a polarizing film formed of a polyvinyl alcohol type resin layer having a dichroic material impregnated therein
Implementation Method 2
absorbing orthogonal polarized light
Implementation Method 3
The circular polarizer consists of a linear polarizer and a quarter-wave plate (QWP). Unpolarized ambient light is polarized by the linear polarizer; the linearly polarized light is converted to circularly polarized light upon passing through the QWP.
Data Source
AI summary
A linear polarizer may be formed a blue dichroic dye compound, having a maximum dichroic ratio Kd≤12 in an entire visible wavelength range, and a red dichroic dye compound, having a maximum dichroic ratio Kd≤16 in the entire visible wavelength range. The linear polarizer has a dichroic ratio Kd≥18 and a thickness of less than or equal to 2 micrometers. The linear polarizer may form an achromatic polarizer.