Electromechanical Polymer Transducers for Low-Voltage Haptic Feedback
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Solution Overview
Problem
Current transducers, such as DEAP elastomers and piezoceramic materials, face challenges in providing high-definition haptic feedback and multimodal responses due to requirements for high voltages, brittleness, and limited strain, making them unsuitable for handheld devices and applications needing localized tactile feedback.
Innovation Solution
Electromechanical polymer (EMP) transducers with electrostrictive polymer layers, capable of generating high strains and vibrations under low driving voltages, are used to provide localized haptic responses, acting as both sensors and actuators, and can produce audible sounds, enabling robust and flexible haptic systems for consumer devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If DEAP elastomer is used to provide electromechanical response, then softness and flexibility are improved, but high driving voltage (1000V or more) is required which poses safety and cost concerns
Solution Approach 1:
The patent changes the material parameter from DEAP elastomer to electrostrictive polymer, which fundamentally alters the electromechanical response characteristics. This material substitution enables the system to achieve the same or better flexibility while operating at significantly lower voltages (50-100 MV/m electric field intensity versus 1000V+ for DEAP), directly resolving the contradiction between softness and voltage requirement
Solution Approach 2:
The patent employs a composite structure consisting of electrostrictive polymer layers combined with electrode patterns and optional substrate materials. This composite approach allows optimization of both mechanical properties (flexibility, softness) and electrical properties (lower operating voltage, higher strain output) simultaneously, resolving the trade-off between ease of operation and energy consumption
2Use of energy by moving object
If piezoceramic material is used to provide force output under low electric voltage, then driving voltage requirement is reduced, but brittleness increases making it unable to withstand shock load
Solution Approach 1:
The patent changes the material phase from crystalline piezoceramic to polymeric electrostrictive material. This parameter change transforms the mechanical properties from brittle to flexible while maintaining the ability to generate force under electric field, and adds the capability to withstand shock loads due to the polymer's inherent toughness and elasticity
Solution Approach 2:
The patent employs a thinner polymer film (20 micrometers or less) compared to what would be needed for other materials, creating a more fragile-seeming structure that is actually more durable due to the polymer material's shock resistance. This resolves the contradiction by using a material that appears vulnerable but performs robustly under stress
3Length of moving object
If DEAP film thickness is reduced to 20 micrometers or less for handheld device application, then flexibility is improved, but electromechanical response becomes insufficient
Solution Approach 1:
The patent changes the material properties from DEAP elastomer to electrostrictive polymer, which has fundamentally different electromechanical coupling characteristics. This material substitution enables thin films (20 micrometers or less) to generate sufficient electromechanical response because the electrostrictive effect produces higher strain output per unit electric field intensity compared to DEAP, overcoming the power limitation while maintaining thinness
Solution Approach 2:
The patent applies specific electrode patterns and configurations to the thin polymer film to optimize the local electric field distribution. This ensures that even at reduced thickness, the electromechanical response is concentrated and sufficient where needed, resolving the contradiction between thinness and power output
4Power
If electrostrictive polymer is used to provide high strain output, then electromechanical response is improved, but electric field intensity of 50-100 MV/m requires careful voltage management
Solution Approach 1:
The patent divides the voltage management into two distinct functional stages: a charging phase that establishes the electric field in the polymer, and a sensing/actuation phase that utilizes the stored field for high-strain output. This segmentation simplifies control by separating the high-voltage charging operation from the lower-voltage operational phase, reducing overall system complexity
Solution Approach 2:
The patent performs preliminary charging of the electrostrictive polymer to establish the required electric field intensity before the actual sensing or actuation operation. This preliminary action stores the necessary energy in the polymer, allowing subsequent high-strain output without requiring continuous high-voltage application, thereby simplifying voltage management during operation
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
EMP transducers offer high strains, flexible manufacturing, and low power consumption, allowing for localized and intense tactile feedback, reducing device power requirements and enabling advanced haptic experiences in portable electronics with fast response times and multimodal capabilities.
Implementation Method 1
electromechanical polymer (EMP) layers... electrostrictive polymer active layer... capable of generating high strains and vibrations under low driving voltages
Implementation Method 2
one or more EMP transducers, each including one or more EMP layers, such as an electrostrictive polymer active layer... capable of serving as both a sensor and an actuator
Data Source
AI summary
A localized multimodal haptic system includes one or more electromechanical polymer (EMP) transducers, each including an EMP layer, such as an electrostrictive polymer active layer. In some applications the EMP transducer may perform an actuator function or a sensor function, or both. The EMP polymer layer has a first surface and a second surface on which one or more electrodes are provided. The EMP layer of the EMP actuator may be 5 microns thick or less. The EMP transducers may provide local haptic response to a local a stimulus. In one application, a touch sensor may be associated with each EMP transducer, such that the haptic event at the touch sensor may be responded to by activating only the associated EMP transducer. Furthermore, the EMP transducer may act as its own touch sensor. A variety of haptic responses may be made available. The EMP transducers may be used in various other applications, such as providing complex surface morphology and audio speakers.