Semiconductor Gas Sensor Laser-Adjusted Diffusion Channels
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Solution Overview
Problem
Existing gas concentration sensors, such as lambda probes, require individual adjustment for each sensor to establish a correlation between pump current and gas concentration, which is inefficient and lacks precision in semiconductor technology.
Innovation Solution
A semiconductor sensor with a cavity and fluid connection featuring a diffusion channel with adjustable openings, closed using laser light, allows for precise adjustment of the sensor's flow properties for gas analysis, including determination of residual oxygen and nitrogen oxides in exhaust gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual adjustment is performed for each sensor to establish correlation between pump current and gas concentration, then measurement precision is improved, but productivity deteriorates due to time-consuming individual calibration
Solution Approach 1:
The sensor is divided into multiple identical units produced in parallel using semiconductor manufacturing techniques. Each sensor unit has the same structure with diffusion channels, but their flow properties can be individually adjusted by selectively closing openings using laser light, allowing rapid calibration without manual adjustment of each sensor's internal components
Solution Approach 2:
The traditional mechanical individual adjustment process is replaced by an optical method using laser light to close openings in the diffusion channels. This substitution enables automated, precise control of fluid flow properties through selective opening closure, significantly reducing calibration time while maintaining measurement precision
2Manufacturing precision
If laser light is used to close openings in diffusion channels, then manufacturing precision is improved for fluid connection geometry, but device complexity increases due to additional adjustment mechanism
Solution Approach 1:
The adjustment mechanism is extracted from the sensor's functional structure. The openings in the diffusion channels serve dual purposes: as structural features during manufacturing and as adjustable flow control elements during calibration. By closing openings with laser light, the adjustment function is achieved without adding separate mechanical adjustment components to the sensor structure
Solution Approach 2:
The openings in the diffusion channels serve multiple functions: they define the fluid connection geometry during manufacturing and serve as adjustable flow control elements during calibration. The same structural features are used for both fabrication precision and operational adjustment, eliminating the need for separate adjustment mechanisms
3Adaptability or versatility
If multiple openings are provided in diffusion channels, then adaptability is improved for flow property adjustment, but device complexity increases due to more openings to manage
Solution Approach 1:
The fluid flow properties are made dynamically adjustable by providing multiple openings that can be selectively closed using laser light. This allows the sensor to adapt its flow characteristics to match individual pump current-concentration correlations, achieving high adaptability through a simple binary state (open/closed) for each opening rather than complex continuous adjustment mechanisms
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
Enables the construction of a semiconductor gas sensor that can be easily calibrated and adjusted for precise gas analysis, improving the correlation between pump current and gas concentration, and allowing for broad adaptation of flow properties.
Implementation Method 1
At least one of the openings may be closed using laser light in order to influence an effective length or an effective cross section of the fluid connection
Implementation Method 2
The material in the area of the opening may include silicon nitride for example, which absorbs infrared radiation to a greater degree such that the material may be molten by an infrared laser
Implementation Method 3
The pump diaphragm is controlled so as to convey exhaust gas through a fluid connection into the cavity or out of the cavity
Implementation Method 4
The lambda probe includes a Nernst cell for determining a difference in the concentration of oxygen between two different gases, namely, the exhaust gas and usually an ambient air
Implementation Method 5
The fluid connection includes a diffusion channel having multiple openings in the inlet area or multiple diffusion channels having respectively one opening in the inlet area
Data Source
AI summary
A semiconductor sensor includes a cavity; a fluid connection between the cavity and an inlet area; a pump diaphragm that bounds the cavity; and a measuring diaphragm that bounds the cavity. The fluid connection includes a diffusion channel having multiple openings in the inlet area or multiple diffusion channels having respectively an opening in the inlet area, and it is possible to close at least one of the openings using laser light in order to influence an effective length or an effective cross section of the fluid connection.