Electroactive Polymer Haptic Layer with Dispersed Beads
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Solution Overview
Problem
Existing haptic devices for display devices, such as those using eccentric rotating mass (ERM), linear resonant actuator (LRA), and piezo ceramic actuators, suffer from low durability, limited vibration range, and require high driving voltage, while electroactive polymer (EAP) devices offer lower vibration strength and are not effectively transmissible through display panels.
Innovation Solution
A touch sensitive element with an electroactive layer, electrodes, and dispersed beads having a diameter larger than the electroactive layer's thickness, which increases the surface area and Young's modulus, enhancing blocking force and vibration strength, allowing effective tactile feedback transmission through display panels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If electroactive polymer (EAP) is used for haptic device, then the device becomes thin and flexible, but vibration strength becomes lower than ERM, LRA, and piezo ceramic actuator
Solution Approach 1:
The patent combines electroactive polymer with a porous substrate to create a composite structure. The porous substrate provides mechanical support and enhances vibration strength while the electroactive polymer maintains the thin and flexible characteristics. This composite approach resolves the contradiction by integrating materials with complementary properties.
Solution Approach 2:
The patent introduces a porous substrate with specific pore structures at strategic locations within the EAP layer. This creates local variations in density and mechanical properties, enhancing vibration strength in critical areas while maintaining overall thinness and flexibility of the device structure.
2Device complexity
If electroactive polymer (EAP) is used for haptic device, then the device becomes thin and flexible, but driving voltage becomes high
Solution Approach 1:
The patent modifies the physical and chemical parameters of the electroactive polymer composite, including pore size, porosity, and material composition, to optimize the electromechanical coupling efficiency. These parameter changes enable the device to achieve desired vibration strength at lower driving voltages while maintaining the thin and flexible structure.
3Force
If existing haptic devices (ERM, LRA, piezo ceramic actuator) are used, then vibration strength is sufficient, but durability becomes low and they easily break due to external impact
Solution Approach 1:
The patent employs a flexible porous substrate that can absorb and distribute external impacts throughout the structure, preventing concentrated stress points that would cause breakage. This flexible film approach maintains sufficient vibration strength while significantly improving durability and resistance to external impact.
4Force
If existing haptic devices are used, then vibration strength is sufficient, but they vibrate the entire display device instead of a specific part
Solution Approach 1:
The patent creates localized vibration by introducing porous structures and varying the electroactive polymer composition in specific regions of the display. This enables different areas to have different mechanical properties, allowing vibration to be concentrated in specific parts rather than propagating throughout the entire display device.
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 solution significantly improves vibration strength and durability, enabling effective tactile feedback transmission through display panels with reduced driving voltage requirements, addressing the limitations of existing haptic devices.
Implementation Method 1
an electroactive layer including an electroactive polymer; a first electrode electrically coupled to a surface of the electroactive layer; a second electrode electrically coupled to a same surface or a different surface of the electroactive layer as the first electrode, the electroactive layer configured to vibrate responsive to applying a voltage difference between the second electrode and the first electrode
Data Source
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AI summary
The touch sensitive element (100) according to an exemplary embodiment of the present disclosure includes an electroactive layer (120), an electrode (110, 140), and a plurality of beads (130). The electroactive layer (120) includes an electroactive polymer. The electrode (110, 140) is disposed on at least one surface of the electroactive layer (120). The plurality of beads (130) is dispersed in the electroactive layer (120) and has a diameter (d) larger than the thickness (t) of the electroactive layer (120).