Airflow Sensor Packaging Structure for Pollutant Diffusion
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Solution Overview
Problem
Airflow sensors in electronic equipment fail to function correctly in environments with fumes or pollutants due to blockage by cigarette oil, leading to false triggering and reduced performance.
Innovation Solution
The airflow sensor design includes a substrate with a back cavity, a vibrating electrode, and a fixed electrode with a gap layer, featuring vent holes only on the insulating layer and pressure equalizing holes on the perimeter edge of the vibrating electrode, forming an air release channel to equalize pressure and prevent contamination, thereby enhancing detection sensitivity and preventing false triggers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vent holes are provided on the fixed electrode to release pollutants, then the sensor can prevent false triggering, but pollutants may enter the sensing cavity and block the holes
Solution Approach 1:
The patent applies local quality by providing vent holes only on the insulating layer portion of the fixed electrode, while the conductive layer remains intact. This localized approach allows pollutant release without compromising the overall sealing of the sensing cavity, enabling the sensor to vent fumes while maintaining protection against pollutant intrusion.
Solution Approach 2:
The insulating layer serves as an intermediary structure that facilitates pollutant venting while protecting the sensing cavity. By placing vent holes in the insulating layer rather than the conductive layer, the patent uses this intermediate layer as a mediator to allow controlled release of accumulated fumes without creating direct pathways for pollutants to enter the sensitive sensing region.
2Reliability
If the conductive layer area is reduced to make space for vent holes, then pollutant release is improved, but the capacitance sensitivity of the sensor decreases
Solution Approach 1:
The patent applies local quality by spatially separating the venting function and sensing function on the fixed electrode. The insulating layer contains vent holes for pollutant release, while the conductive layer maintains its full area for optimal capacitance sensing. This localized functional separation allows both pollutant diffusion and high measurement precision to coexist without compromising either performance.
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 prevents false triggering and contamination, maintaining the airflow sensor's performance and extending its service life by allowing smooth diffusion of pollutants and maintaining the capacitance sensitivity without altering the sensor's volume.
Implementation Method 1
the vibrating electrode and the fixed electrode form a variable capacitor
Implementation Method 2
Changes in air pressure will cause the diaphragm to deform, and the capacitance between the diaphragm and the backplane to change
Data Source
AI summary
Disclosed an airflow sensor and an airflow sensor packaging structure. The airflow sensor comprises a base, a vibrating electrode, and a fixed electrode in a stacked arrangement, wherein the base has a back cavity passing through in its thickness direction. it is intended that the fixed electrode of the air flow sensor is provided with a vent hole and the perimeter edge of the vibration sensitive area of the vibration electrode is provided with a pressure equalizing hole. In the thickness direction of the substrate, the pressure equalizing hole The projection overlaps with the projection of the vent hole, and the pressure equalizing hole, the vent hole and the gap layer channel jointly form an air release channel, which is conducive to the smooth diffusion of oil smoke entering the air flow sensor along the air release channel.