Piezoelectric Switch Eliminates Display Scanning for Power Mode Control
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Solution Overview
Problem
Portable electronic devices with touch-sensitive displays consume significant power due to periodic scanning required to detect touch events, leading to increased power consumption in sleep or off modes.
Innovation Solution
Incorporating a piezoelectric switch that generates an electric charge in response to externally applied forces, allowing the device to switch between power modes without periodic scanning of the touch-sensitive display, using an actuator to engage the piezoelectric element and trigger mode changes based on the generated charge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If periodic scanning is used to detect touch events on the display screen, then touch sensitivity is maintained, but power consumption increases significantly
Solution Approach 1:
The patent extracts the touch detection function from the continuous display scanning process by introducing a separate piezoelectric sensor system. This allows the display to stop periodic scanning while touch events can still be detected through the piezoelectric elements that sense mechanical stress independently of the display refresh cycle.
Solution Approach 2:
The piezoelectric switch acts as an intermediary between the physical touch event and the electronic detection system. When a user touches the display, the mechanical force is converted into an electrical signal by the piezoelectric element, which then triggers the processor to wake from sleep mode without requiring continuous display scanning.
2Speed
If the device remains in full-power mode to ensure immediate responsiveness, then response time is minimized, but battery life is reduced
Solution Approach 1:
The piezoelectric switch is pre-positioned and continuously monitored in a low-power state, ready to immediately detect and respond to touch events. This preliminary preparation allows the system to maintain rapid response capability while staying in sleep mode, as the piezoelectric sensor requires minimal power to remain sensitive to mechanical stress.
Solution Approach 2:
Instead of continuous full-power operation, the system uses periodic wake-up triggered by piezoelectric detection. The processor alternates between sleep mode and active state, waking only when the piezoelectric switch detects a touch event, thereby reducing overall power consumption while maintaining responsiveness.
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
This solution reduces power consumption by eliminating the need for continuous scanning, allowing the device to wake up from sleep or off modes efficiently and conserve energy, thereby extending battery life.
Implementation Method 1
a piezoelectric switch connected to the processor and disposed in the housing, the piezoelectric switch comprising a piezoelectric element which generates an electric charge in response to forces applied to the piezoelectric element
Data Source
AI summary
The present disclosure provides a method of switching power modes on a portable electronic device and a portable electronic device configured to perform the same. In accordance with one embodiment, there is provided a portable electronic device, having a housing; a processor received within the housing; a display screen connected to the processor and exposed by the housing; a piezoelectric switch connected to the processor disposed in the housing, the piezoelectric switch having a piezoelectric element which generates an electric charge in response to forces applied to the piezoelectric element; and an actuator for engaging the piezoelectric element, the actuator being exposed by the housing and movable within the housing to transfer externally applied forces to the piezoelectric element; wherein the processor is configured for switching between at least two power modes in response to the generation of the electric charge by the piezoelectric element.