Electronic Cigarette Airflow Sensor Condensate Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electronic cigarettes face safety hazards due to aerosol condensate contacting the capacitance detection circuit, leading to self-starting issues.
Innovation Solution
The electronic cigarette design incorporates a MEMS airflow sensor with a recessed first bonding pad and a ring-shaped second bonding pad, both connected via pins to a main control IC, where the second pin is grounded, preventing condensate from reaching the capacitance detection circuit, and a waterproof sleeve to protect against aerosol ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional PCB is used for the airflow sensor, then the device structure is simple, but condensate contacts the capacitance detection circuit causing self-starting safety hazards
Solution Approach 1:
A waterproof coating layer is applied to the PCB as an intermediary protective barrier between the condensate and the capacitance detection circuit. This coating prevents direct contact between the harmful condensate and the sensitive electronic components, eliminating the self-starting safety hazard while maintaining the simplicity of the PCB structure.
Solution Approach 2:
The grounding structure is designed to utilize the condensate's natural flow path by providing a dedicated grounding pad that attracts and collects condensate. By intentionally creating a grounded area that condensate is drawn to, the design converts the harmful condensate into a benign element that grounds itself away from the capacitance detection circuit, preventing interference while maintaining circuit simplicity.
2Ease of manufacture
If the bonding pads are exposed on the circuit board, then the manufacturing process is simple, but condensate can reach the capacitance detection circuit
Solution Approach 1:
A waterproof coating layer is applied over the bonding pads and circuit board as an intermediary protective barrier. This coating allows the bonding pads to remain structurally simple and easy to manufacture while preventing condensate from reaching and contacting the electrical components, thus eliminating the harmful effect without complicating the manufacturing process.
Solution Approach 2:
A thin waterproof film or coating is applied to the PCB surface, particularly over the bonding pads and capacitance detection circuit areas. This thin film provides effective protection against condensate contact while maintaining the simplicity of the underlying PCB structure and not significantly increasing manufacturing complexity.
3Device complexity
If no waterproof protection is provided, then the device structure is simple, but aerosol condensate enters the capacitance detection circuit causing self-starting
Solution Approach 1:
A waterproof coating layer serves as an intermediary protective barrier applied to the PCB and bonding pads. This simple coating structure prevents aerosol condensate from reaching the capacitance detection circuit, eliminating the self-starting hazard while adding minimal structural complexity to the device.
Solution Approach 2:
The grounding pad is designed to actively attract and collect condensate through its grounded nature. By providing a designated grounding area, the design converts the potentially harmful condensate into a benign element that naturally flows to the grounded pad away from the capacitance detection circuit, preventing self-starting without requiring complex waterproof structures.
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 configuration effectively prevents condensate from contacting the capacitance detection circuit, preventing self-starting and ensuring the electronic cigarette is safe, reliable, and cost-effective.
Implementation Method 1
the air passes through the airflow sensor, making a conductive film of the airflow sensor to deform, thereby causing a change in an equivalent capacitance
Implementation Method 2
The airflow sensor comprises a micro-electro-mechanical system (MEMS) chip
Implementation Method 3
an aerosol may flow back into a cavity of the electronic cigarette, and some of the aerosol condense on a surface of the cavity
Data Source
AI summary
An electronic cigarette includes an atomizer, an e-liquid cavity, and an airflow sensing device. The airflow sensing device includes a first circuit board, a MEMS airflow sensor, and a main control IC. A second control board includes a first bonding pad and a second bonding pad. The second bonding pad is disposed around the first bonding pad. The first bonding pad includes a first pin and the second bonding pad includes a second pin. Since the first bonding pad is surrounded and sealed by the second bonding pad, the first pin is electrically connected to a capacitance detection port of the main control IC, and the second pin is grounded, condensate is prevented from contacting the first pin, thus preventing the condensate from flowing through a capacitance detection circuit. The main control IC does not detect an increase in capacitance value, which prevent the electronic cigarette from self-starting.