Polyurethane Film for Haptic Displays
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Solution Overview
Problem
Existing haptic display films face challenges in achieving a balance between high dielectric constant and low modulus characteristics, which affects their electroactivity, permeability, and haze characteristics, making them unsuitable for haptic displays.
Innovation Solution
A polyurethane film with a dielectric constant/elastic modulus value of 2 to 15 mm2/N is developed by mixing polyol with polyisocyanate, optimizing the strain of the dielectric elastomer to enhance electroactivity and optical characteristics, while maintaining low crosslinking density to prevent tearing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a dielectric material is used to achieve high dielectric constant, then electroactivity is improved, but the material becomes rigid and prone to tearing
Solution Approach 1:
The patent changes the physical and chemical parameters of the dielectric material by controlling crosslinking density and molecular structure. By adjusting the crosslinking degree and using specific polyurethane compositions, the material achieves optimal balance between dielectric constant (electroactivity) and mechanical strength (tear resistance), resolving the contradiction between electrical performance and mechanical durability
Solution Approach 2:
The patent employs composite material design by combining polyol and polyisocyanate in specific ratios to create polyurethane films with optimized properties. The composite structure allows simultaneous achievement of high dielectric constant for electroactivity and appropriate mechanical strength to prevent tearing during operation
2Strength
If crosslinking density is increased to improve mechanical strength, then tear resistance is improved, but electroactivity decreases
Solution Approach 1:
The patent optimizes the crosslinking density parameter within a specific range rather than maximizing it. By controlling the crosslinking degree to an optimal level, the material maintains sufficient mechanical strength for tear resistance while preserving the dielectric properties necessary for high electroactivity, thus resolving the inverse relationship between these two properties
3Power
If PVDF film is used to achieve piezoelectric effect, then haptic feedback is improved, but haze increases due to crystallinity
Solution Approach 1:
The patent substitutes the piezoelectric system (PVDF) with a dielectric elastomer system (polyurethane film). This replacement eliminates the crystallinity-induced haze problem associated with PVDF while maintaining haptic feedback functionality through dielectric actuation, thus resolving the contradiction between haptic performance and optical clarity
4Power
If dielectric constant is increased to improve electroactivity, then haptic performance is improved, but the film becomes more prone to tearing
Solution Approach 1:
The patent simultaneously optimizes multiple parameters including dielectric constant, crosslinking density, and molecular weight of polyurethane. By coordinating changes in these parameters, the film achieves high dielectric constant for improved haptic performance while maintaining adequate mechanical strength and tear resistance through controlled crosslinking and molecular structure
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 polyurethane film exhibits improved haptic performance, excellent permeability, and haze characteristics, enabling effective application in haptic displays with enhanced vibration acceleration and optical clarity.
Implementation Method 1
a polymer such as urethane, which uses a dielectric system in which a dielectric material shrinks and expands in a vertical direction when the dielectric material is charged
Data Source
AI summary
The present invention relates to a polyurethane film for displays, which has high dielectric constant and low modulus characteristics and a dielectric constant/elastic modulus value of 2 to 15 mm2/N, and a production method thereof.