Thin Polarizer Resists Red Discoloration via Retardation Ratio
Solution Overview
Problem
Conventional polarizing plates with small thicknesses are prone to red discoloration during heat resistance tests, and existing methods to suppress this issue, such as adding zinc ions, pose environmental and health concerns.
Innovation Solution
A polarizer with a polyvinyl alcohol-based resin layer and iodine adsorbed and oriented, having a thickness of less than or equal to 10 μm and a retardation ratio of iodine to polyvinyl alcohol greater than or equal to 0.38, which stabilizes the iodine-polyvinyl alcohol complex to resist red discoloration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the thickness of the polarizer is reduced to meet the requirement for thin and light mobile devices, then the weight and thickness requirements are satisfied, but red discoloration occurs during heat resistance tests
Solution Approach 1:
The patent changes the chemical composition parameters by introducing boron compounds and controlling the ratio of iodine to polyvinyl alcohol (specifically setting Ri/Rpva ≥ 0.38). It also controls the molecular weight and degree of saponification of the polyvinyl alcohol to prevent red discoloration while maintaining thin film structure
Solution Approach 2:
The patent creates a composite structure by combining polyvinyl alcohol with boron compounds (such as boric acid, borax, or boron-containing crosslinking agents) to form a stabilized complex. This composite material prevents red discoloration during heat resistance tests while maintaining the required thin thickness
2Reliability
If conventional methods such as adding zinc ions are used to suppress red discoloration, then heat resistance is improved, but environmental pollution and skin irritation problems occur
Solution Approach 1:
The patent replaces harmful heavy metal ions (zinc) with environmentally benign boron compounds. Boron is naturally occurring, non-toxic, and does not cause skin irritation or environmental pollution, thus eliminating the harmful effects associated with conventional methods
Solution Approach 2:
The patent changes the chemical additive from harmful zinc ions to safe boron compounds, fundamentally altering the composition to eliminate environmental and health hazards while maintaining the heat resistance function
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 polarizer effectively resists red discoloration and maintains neutral display even under prolonged heat resistance testing, ensuring high heat resistance and image clarity in thin-film applications.
Implementation Method 1
iodine adsorbed and oriented in the polyvinyl alcohol-based resin layer
Implementation Method 2
iodine adsorbed and oriented in the polyvinyl alcohol-based resin layer
Data Source
AI summary
Provided are a polarizer that resists red discoloration in a heat resistance test even when it has a small thickness, and a polarizing plate including the polarizer. The polarizer includes a polyvinyl alcohol-based resin layer and iodine adsorbed and oriented in the polyvinyl alcohol-based resin layer, and has a thickness less than or equal to 10 μm and a ratio of a retardation of iodine to a retardation of polyvinyl alcohol greater than or equal to 0.38.