Movable Seal Microphone Protection Against Sonic Overpressure
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Solution Overview
Problem
Portable mobile devices' microphones are prone to damage from sudden mechanical and atmospheric shocks, leading to functional losses and unexpected behavior due to sonic pressure effects.
Innovation Solution
Incorporating movable seals, expandable elements, and bistable structures within the microphone assembly that can alter their state in response to sonic pressure or shocks to protect the microphone, allowing ordinary sound waves to pass while blocking or venting excessive pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealed cavity is used to protect the microphone from sonic pressure, then the microphone is protected from damage, but ordinary sound waves cannot reach the diaphragm
Solution Approach 1:
The seal is designed to be movable rather than fixed, allowing it to dynamically change position between blocking and non-blocking states. The seal can be actuated by electromagnetic circuits, bimetallic strips, or other mechanisms that respond to sonic overpressure or shock detection, enabling the system to adapt its sealing behavior based on environmental conditions while maintaining normal acoustic transmission during regular operation.
2Ease of operation
If a movable seal is introduced to allow sound waves to pass, then the microphone can function normally, but the protection against sonic overpressure is reduced
Solution Approach 1:
The movable seal is positioned in advance to block the sonic pathway before sonic overpressure or shock occurs. The seal can be pre-positioned in the blocked state and only moved to allow sound transmission when normal operating conditions are detected, or pre-positioned to allow transmission and automatically moved to blocked state upon detection of abnormal pressure or shock conditions.
Solution Approach 2:
The seal mechanism converts the harmful effect of sonic overpressure into a beneficial protective action. When sonic overpressure or shock occurs, the seal automatically moves to block the pathway, using the harmful pressure wave itself to trigger the protective blocking action, thereby protecting the microphone from damage.
3Reliability
If electromagnetic circuits or sensors are added to control the seal, then the seal can respond to shocks and sonic pressure, but the device complexity increases
Solution Approach 1:
The seal system is designed to be self-actuating without requiring external control systems. The seal responds automatically to sonic overpressure or shock conditions through passive mechanisms such as bimetallic strips that bend in response to pressure changes, or through the direct mechanical action of the pressure wave itself on the seal structure, eliminating the need for complex electromagnetic circuits or external sensors.
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 protects the microphone from damage by blocking or dissipating sonic pressure, maintaining functionality and reducing noise distortion, while allowing acoustic signals to be received.
Implementation Method 1
sonic pressure can actuate the movable seal, such as by pushing the seal into place
Implementation Method 2
the shock itself can actuate the movable seal, such as by accelerating a portion of the seal or a weight attached thereto
Implementation Method 3
the movable seal can be actuated by an electromagnetic circuit, which can be responsive either to sonic overpressure or to a shock
Implementation Method 4
a bimetallic strip, an electromagnetic strip, a memory-metal alloy, a solenoid, or another element having a mechanical response to an electrical or electromagnetic signal
Implementation Method 5
the cavity can include compressible or soft elements, disposed to expand the cavity in the event of sonic overpressure, or even to de-link the cavity in the event of sonic overpressure
Implementation Method 6
which can be responsive either to sonic overpressure or to a shock (such as in response to an accelerometer or another type of inertial response sensor)
Data Source
AI summary
A microphone includes elements to protect against overpressure, such as from sudden physical shock. A cavity between ambient atmosphere and the microphone diaphragm includes a movable seal, which blocks overpressure from reaching the diaphragm when closed, and allows ordinary pressure to reach the diaphragm when open. The cavity can also have an entrance from ambient atmosphere offset from an exit to the diaphragm, and can include a valve which vents overpressure, or balloons in response to overpressure, so that overpressure does not directly reach the diaphragm. The seal or valve can be kept open or kept closed, and moved between states in response to whether the microphone should be in use or protected.