Optical CO2 Sensor IC with Differential Light Detection
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Solution Overview
Problem
Existing integrated circuits (ICs) with CO2 sensors face challenges in achieving high sensitivity while being cost-effective, particularly for impedometric CO2 sensors, which are bulky and expensive due to complex manufacturing processes and low production yield.
Innovation Solution
An integrated circuit (IC) with an optical CO2 sensor design featuring first and second light sensors and a layer containing organic compounds with amine or amidine functional groups, which change transmissivity upon CO2 exposure, allowing for accurate CO2 concentration determination using a signal processor to calculate the difference in output signals from both sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If impedometric CO2 sensors are used, then CO2 detection capability is achieved, but sensitivity is poor and device size is large
Solution Approach 1:
The patent replaces the traditional impedometric sensing mechanism with an optical sensing mechanism. Instead of measuring electrical impedance changes, the invention uses light transmission through an organic compound layer that changes transmissivity when CO2 binds to amine functional groups, thereby achieving high sensitivity with a compact structure
Solution Approach 2:
The patent utilizes the dynamic parameter change of organic compounds (specifically amine-containing compounds) that undergo chemical transformation when exposed to CO2. The binding of CO2 to amine groups alters the optical properties (transmissivity) of the compound, enabling sensitive detection through optical measurement rather than electrical measurement
2Adaptability or versatility
If multiple discrete sensors are integrated in an IC, then sensing capability is achieved, but manufacturing complexity increases and production yield decreases
Solution Approach 1:
The patent merges the CO2 sensing function directly into the IC substrate by integrating the organic compound layer with the light sensor structure. This consolidation eliminates the need for separate discrete sensor components and their associated complex assembly processes, thereby simplifying manufacturing while maintaining sensing functionality
Solution Approach 2:
The IC design incorporates a universal sensing platform where the organic compound layer can be integrated with standard IC manufacturing processes. The light sensor and signal processor work together to provide CO2 detection capability that is seamlessly embedded in the IC, enabling multi-functionality without requiring specialized manufacturing steps
3Measurement precision
If organic compound layer is added over light sensor, then CO2 sensitivity is improved, but additional manufacturing steps are required
Solution Approach 1:
The patent exploits the reversible parameter change of organic compounds between bound and unbound states with CO2. The amine-containing compound transitions from a transparent state to a clouded state upon CO2 binding, and this reversible transformation enables accurate CO2 concentration measurement through optical detection
Solution Approach 2:
The patent utilizes the optical property change (clouding effect) of the organic compound when CO2 binds to it. The change in light transmissivity through the organic layer serves as a direct visual and measurable indicator of CO2 presence and concentration, enabling sensitive detection without complex electronic processing
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 IC provides a compact, cost-effective solution for sensitive CO2 detection, enhancing manufacturing efficiency and reducing production costs by utilizing organic compounds that alter transmissivity or color in response to CO2, enabling precise CO2 level measurement without requiring additional processing steps.
Implementation Method 1
a layer portion including an organic compound comprising at least one amine or amidine functional group for reacting with CO2 over the first light sensor
Implementation Method 2
which have the ability to cloud or otherwise alter their transmissivity including changing their colour upon exposure to CO2
Implementation Method 3
a signal processor coupled to the first and second light sensor for determining a difference in the respective outputs of the first and second light sensor
Data Source
Figure 1~2B
Figure 3(a)~3(c)
Figure 4~5
AI summary
Disclosed is an integrated circuit comprising a substrate (10); and an optical CO2 sensor comprising: first and second light sensors (12, 12') on said substrate, said second light sensor being spatially separated from the first light sensor; and a layer portion (14) including an organic compound comprising at least one amine or amidine functional group over the first light sensor; wherein said integrated circuit further comprises a signal processor (16) coupled to the first and second light sensor for determining a difference in the respective outputs of the first and second light sensor. An electronic device comprising such a sensor and a method of manufacturing such an IC are also disclosed.