Pressure Sensor Liquid Ejection Using a Magnetic Actuator
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Solution Overview
Problem
Portable electronic devices with pressure sensors face issues due to liquid occlusion, which leads to unreliable pressure readings and errors, as liquid infiltration blocks airflow and causes capillary forces, resulting in significant fluctuations in pressure measurements.
Innovation Solution
A magnetic actuator is used to create a syringe-like mechanism that expels trapped liquid by leveraging the motion of a magnet within a coil, adjusting the protective cap's movement frequency to unclog apertures and restore airflow, and breaking hardened crusts formed by particle accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is exposed to the external environment through an opening, then barometric pressure measurements can be obtained, but liquid infiltration can block airflow and cause capillary forces leading to unreliable readings
Solution Approach 1:
The system performs preliminary detection of liquid occlusion by monitoring pressure readings and identifying patterns indicative of liquid presence. When liquid occlusion is detected, the magnetic actuator is activated to expel the liquid before it can significantly degrade measurement accuracy, preventing the harmful effect rather than just responding to it.
Solution Approach 2:
The patent replaces traditional mechanical clearing mechanisms with a magnetic actuator system. The magnetic actuator uses electromagnetic fields to generate motion that expels liquid from the sensor opening, substituting complex mechanical structures with a more compact and controllable electromagnetic system.
2Reliability
If liquid occlusion is detected and cleared using traditional methods, then pressure readings can be restored, but prolonged waiting periods are required
Solution Approach 1:
The system employs periodic detection of pressure readings to identify liquid occlusion events. When detected, the magnetic actuator is activated for brief periodic pulses to expel the liquid, rather than requiring continuous operation or prolonged waiting periods. This periodic action restores functionality quickly and efficiently.
Solution Approach 2:
Instead of allowing liquid to evaporate naturally over prolonged periods, the magnetic actuator actively expels the liquid in rapid succession, rushing through the clearing process. This skips the slow evaporation phase and directly removes the occluding liquid, restoring sensor functionality in seconds rather than minutes or hours.
3Productivity
If a magnetic actuator is used to expel liquid occlusion, then clearing time is reduced to seconds, but device complexity increases
Solution Approach 1:
The magnetic actuator serves multiple functions: it expels liquid occlusion from the pressure sensor opening, can clear particulate matter, and may assist in maintaining aperture patency. This multi-functionality justifies the added complexity by providing several benefits from a single component.
Solution Approach 2:
The magnetic actuator acts as an intermediary component between the sensor opening and the external environment. Rather than directly modifying the sensor or the liquid, the actuator mediates the interaction by generating controlled motion to expel occluding substances, simplifying the overall system architecture.
4Object-generated harmful factors
If the magnetic actuator generates repulsive force to expel liquid, then liquid occlusion is effectively removed, but energy consumption increases
Solution Approach 1:
The magnetic actuator is activated only partially or intermittently to expel liquid occlusion, rather than operating continuously. The system applies just enough energy to achieve the clearing objective, using excessive action only when necessary to overcome liquid adhesion forces, thereby optimizing energy consumption.
Solution Approach 2:
The system changes operational parameters of the magnetic actuator based on detected conditions. When liquid occlusion is detected, the actuator parameters (current, pulse duration, frequency) are adjusted to provide the necessary repulsive force. When no occlusion is present, parameters are reduced or operation is suspended, minimizing energy consumption.
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 effectively expels liquid occlusion within seconds, reducing the need for prolonged waiting periods and ensuring accurate pressure sensor readings by restoring airflow and preventing particle-induced pressure errors.
Implementation Method 1
A magnetic actuator is used to create a syringe-like mechanism that expels trapped liquid by leveraging the motion of a magnet within a coil
Implementation Method 2
The sensor data may be indicative of a change in capacitance that satisfies criteria indicative of occlusion
Data Source
AI summary
Aspects of the subject technology relate to electronic devices with pressure sensors. Pressure sensor occlusion may be mitigated by ejecting occluding liquid with a repulsive force from a motion generated with a magnetic actuator associated with the pressure sensor. Processing circuit of the electronic device can detect that the opening is occluded. The processing circuitry activates, when an occlusion is detected, the magnetic actuator by applying an electrical current to a coil in the magnetic actuator and ejects the liquid occlusion in the opening by generating a mechanical motion with a magnet in the magnetic actuator based on the applied electrical current to the coil.