UV LED Gas Sensor Controller With Offset Calibration
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Solution Overview
Problem
Conventional metal-oxide based thin film sensors lack selectivity and require high operating temperatures, leading to limited usability and reliability issues, especially in detecting specific chemical species like explosives, which are challenging due to low vapor pressures and noisy environments.
Innovation Solution
A semiconductor nanostructure functionalized with metal or metal-oxide nanoparticles forms a hybrid sensor that enables light-assisted sensing, controlled by an Application Specific Integrated Circuit (ASIC) to provide accurate gas concentration readings, using pulse width modulation and calibration to enhance selectivity and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional metal-oxide based thin film sensors are used, then high operating temperatures can be achieved, but selectivity deteriorates and reliability worsens
Solution Approach 1:
The patent changes the operating temperature parameter from high (conventional) to room temperature (invention), fundamentally altering the sensor's operational conditions. This is achieved through the hybrid nanostructure design that enables sensitive detection without thermal activation, thereby improving reliability while maintaining functionality
Solution Approach 2:
The patent employs a composite hybrid structure combining semiconductor nanostructures with metal or metal-oxide nanoparticles. This composite material approach enables the sensor to achieve both high sensitivity and selectivity at room temperature, resolving the contradiction between conventional high-temperature operation and reliable performance
2Temperature
If conventional metal-oxide based thin film sensors are used, then high operating temperatures are required, but selectivity deteriorates
Solution Approach 1:
The patent fundamentally changes the temperature parameter from high operating conditions to room temperature operation. This parameter change, enabled by the hybrid nanostructure, allows the sensor to achieve superior selectivity for distinguishing different chemical species without the thermal broadening that plagues conventional sensors
Solution Approach 2:
The patent applies local quality by functionalizing specific regions of the semiconductor nanostructure with metal or metal-oxide nanoparticles. This localized functionalization creates distinct active sites with different affinities for various chemical species, thereby enhancing selectivity through spatially differentiated sensing capabilities
3Measurement precision
If nanowire structures are used to increase active surface area, then sensitivity improves, but device complexity increases
Solution Approach 1:
The patent segments the sensor structure into distinct functional components: the semiconductor nanostructure provides the conductive backbone, while metal or metal-oxide nanoparticles provide the active sensing sites. This segmentation allows each component to be optimized independently and facilitates simpler fabrication processes compared to monolithic nanowire structures
Solution Approach 2:
The semiconductor nanostructure serves multiple functions simultaneously: it provides the electrical conduction pathway, supports the nanoparticle functionalization, and contributes to the overall sensing mechanism. This multi-functionality reduces device complexity by eliminating the need for separate components that would otherwise be required
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 hybrid sensor achieves selective detection of chemicals at room temperature with high sensitivity, distinguishing between different classes of compounds, such as aromatic compounds and explosives, with improved response times and reduced power consumption.
Implementation Method 1
An Application Specific Integrated Circuit (ASIC) controls the sensor device. The ASIC generates a pulse width modulated (PWM) signal for driving a ultraviolet (UV) light emitting diode (LED)
Implementation Method 2
sensors which include a semiconductor nanostructure and at least one of metal or metal-oxide nanoparticles functionalizing the nanostructure and forming a hybrid sensor that enables light-assisted sensing of a target analyte
Data Source
AI summary
An Application Specific Integrated Circuit (ASIC) configured to control one or more gas sensors includes a light emitting diode (LED) driver which receives a pulse width modulator (PWM) signal for driving at least one ultraviolet (UV) LED, wherein an output of the at least one UV LED activates the one or more gas sensors; and an amplifier front end and an analog to digital converter (ADC) configured to calibrate an output of an amplifier to remove offsets associated with outputs associated with the one or more gas sensors, wherein calibration of the amplifier occurs after both generation of the PWM signal and entering a steady state by the one or more gas sensors in which the one or more sensors are not exposed to any gas but air and the amplifier receives one or more inputs associated with the one or more gas sensors.