Shape Memory Alloy Tactile Feedback for Touch Screens
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Solution Overview
Problem
Touch screen devices lack desirable tactile feedback, leading to a poor user experience due to their inability to provide effective haptic sensations, which is essential for user interaction and input confirmation.
Innovation Solution
A portable electronic device with a touch screen display that incorporates a shape memory alloy wire system, where electric current is used to change the shape of the alloy, causing the touch screen to move relative to its base, providing tactile feedback through mechanical movement in response to user input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional touch screen devices are used, then device portability and space efficiency are improved, but tactile feedback quality deteriorates
Solution Approach 1:
The patent replaces traditional mechanical tactile feedback mechanisms (such as buttons or levers) with a shape memory alloy wire system that uses thermal-mechanical properties to generate tactile sensations. The shape memory alloy wires are positioned to contact the touch screen at specific locations and can change their shape in response to electrical current, providing localized tactile feedback without requiring additional mechanical components.
Solution Approach 2:
The patent utilizes the temperature-dependent shape memory properties of the alloy wires. By applying electrical current, the wires undergo a phase transformation from martensite to austenite, changing their shape and providing tactile feedback. This parameter change (temperature-induced shape transformation) enables the system to provide tactile feedback without mechanical actuators.
2Loss of information
If audio output and vibrational devices are used for feedback, then information delivery is improved, but tactile quality deteriorates
Solution Approach 1:
The shape memory alloy wires act as an intermediary between the touch screen interface and the user's tactile sense. Rather than relying on audio or vibration to convey feedback information, the wires directly contact the user's finger through the touch screen, providing a tactile sensation that confirms input while maintaining visual display integrity.
3Ease of operation
If shape memory alloy wire system is implemented, then tactile feedback quality is improved, but device complexity increases
Solution Approach 1:
The shape memory alloy wires serve multiple functions: they provide structural support for the touch screen, act as heating elements for thermal management, and generate tactile feedback through shape transformation. This multi-functionality reduces the need for separate components and simplifies the overall system architecture despite the advanced material properties involved.
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 enhances user interaction by providing a tangible tactile response, improving the overall user experience by confirming input actions through physical movement of the touch screen, thus addressing the lack of haptic feedback in traditional touch screen devices.
Implementation Method 1
A shape memory alloy 32 is disposed between the base 22 and the display device 26 and is configured to change shape in response to conduction of an electric current
Data Source
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Figure 3
Figure 4A
AI summary
An electronic device includes a base, a touch screen display, a shape memory alloy and operational components. The touch screen display is connected to the base and moveable relative to the base and includes a display device and a touch-sensitive input surface overlying the display device and connected to a controller for determining a touch event to the touch-sensitive input surface. The shape memory alloy is disposed between the base and the display device and is configured to change shape in response to conduction of an electric current to cause movement of the display device relative to the base. The operational components include a processor between the base and the touch screen display. The processor is operatively connected to the controller, the display device and the shape memory alloy for causing conduction of current through the shape memory alloy in response to the touch event, resulting in movement of the display relative to the base.