Low Profile Surface Mount Microphone with Ceramic Back Plate
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Solution Overview
Problem
Existing surface mountable condenser microphones are too bulky and thick for applications such as airplane surfaces and wind turbine blades, as they project significantly over the mounting surface, which can interfere with measurements and create air turbulences.
Innovation Solution
A surface mountable condenser microphone design featuring a ceramic back plate with a conductive and non-conductive spacer layer, a diaphragm spaced by a fixation element, and a venting channel to minimize projection and ensure flatness, allowing for a robust and thin housing with a defined air gap between the diaphragm and the conductive capacitor layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional surface mountable condenser microphones are used, then they provide adequate sound capture functionality, but they project significantly over the mounting surface creating air turbulences and interfering with measurements
Solution Approach 1:
The patent merges the back plate and spacer into a single integrated component. The back plate includes an integrally formed spacer that protrudes into the acoustic chamber, eliminating the need for separate spacer components. This integration reduces the overall number of parts and minimizes the projection height of the microphone while maintaining the air gap necessary for acoustic functionality.
Solution Approach 2:
The invention repositions the spacer from a separate component to an integrated feature of the back plate in the vertical dimension. By forming the spacer as part of the back plate structure, the design achieves the necessary spacing function while reducing the overall thickness of the microphone assembly, thereby minimizing projection over the mounting surface.
2Device complexity
If multiple separate components are used for back plate and spacer, then assembly flexibility is provided, but the microphone becomes thicker and more complex
Solution Approach 1:
The patent combines the back plate and spacer into a single integrated component. The back plate includes an integrally formed spacer that protrudes into the acoustic chamber, eliminating the need for separate spacer components. This integration reduces the overall number of parts and simplifies the microphone structure while maintaining the necessary air gap for acoustic functionality.
Solution Approach 2:
The integrated back plate serves multiple functions simultaneously: it provides the structural base for the microphone, forms the spacer to maintain the air gap, and contributes to the overall housing structure. This multi-functionality reduces the need for separate specialized components, thereby reducing overall device complexity and thickness.
3Length of stationary object
If the microphone housing is made thinner to reduce projection, then it may compromise structural robustness and assembly stability
Solution Approach 1:
The integration of the spacer into the back plate creates a more rigid and stable structure. The protruding spacer forms part of the back plate's structural geometry, distributing mechanical stresses more effectively than separate components could. This integrated structure maintains robustness while reducing overall thickness.
Solution Approach 2:
The back plate is formed from a composite structure combining the base plate material with the spacer material in a single integrated component. This composite construction provides both the structural strength of the base plate and the spacing function of the spacer, achieving robustness in a thinner profile through material integration rather than component stacking.
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 design results in a flat, robust, and thin microphone that minimizes air turbulences, enabling accurate measurement of physical parameters like sound and pressure without interfering with airflow, achieving a thickness of 1 mm or less.
Implementation Method 1
arrange a venting channel from the back volume to the area outside of the housing of the condenser microphone to ensure that the average static pressure on both sides of the diaphragm is equal
Implementation Method 2
a diaphragm spaced by a spacer from a conductive capacitor layer, which is arranged on a surface of a back plate
Implementation Method 3
The condenser microphone disclosed is an electret condenser microphone
Data Source
AI summary
A surface mountable condenser microphone (1) comprising a diaphragm (7) spaced by a spacer from a conductive capacitor layer (14), which is arranged on a surface of a back plate (15), wherein the back plate (15) is realized by a ceramic plate that carries the conductive capacitor layer (14) and isolated on another surface area of the same side of the back plate (15) a spacer layer (23) that projects over the conductive capacitor layer (14) and forms the spacer.