Shape Memory Alloy Lifting Key for Slim Electronic Modules

The patent replaces the traditional mechanical stepper motor system with a shape memory alloy-based actuation system. The shape memory alloy wire, when heated by passing current through it, changes shape to drive the functional module (e.g., camera lens) to extend or retract. This substitution eliminates the need for complex mechanical motors and gear systems, significantly reducing the thickness of the electronic device while maintaining the switching functionality.

The patent utilizes the temperature-dependent shape change property of shape memory alloy materials. By changing the temperature parameter (through electrical heating), the shape memory alloy wire transforms between different shapes, thereby controlling the extension and retraction of functional modules. This parameter-based actuation method replaces mechanical motor control with thermal-field control, reducing device thickness.

The patent replaces the bulky mechanical stepper motor system with a compact shape memory alloy wire-based actuation system. The shape memory alloy wire can be wound in a compact spiral configuration and provides sufficient actuation force when heated electrically. This substitution dramatically reduces the volume of the lifting mechanism while maintaining the ability to extend and retract functional modules such as cameras, flashes, or antennas.

The patent exploits the phase transition property of shape memory alloys between austenite and martensite phases. When heated above the transformation temperature, the alloy transitions to the austenite phase and recovers its original shape, providing actuation force. When cooled, it transitions back to the martensite phase and becomes soft and flexible. This phase transition mechanism enables compact, motor-free actuation of functional modules.