Electrochromic Spectrometer Lock-In Detection
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Solution Overview
Problem
Infrared spectrometers require cooling to enhance signal-to-noise ratio, which hinders miniaturization and increases cost, while thermal detectors offer lower detectivity and temperature-dependent performance, leading to decreased accuracy.
Innovation Solution
A compact spectrometer design incorporating an electrochromic modulation unit, optical filter, and integrated circuit for temporal modulation and lock-in detection, allowing for accurate detection of electromagnetic radiation without cooling, using a light-emitting diode emitter and optical detectors with low detectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cooling is applied to the detector to increase signal-to-noise ratio, then detection accuracy is improved, but device size and complexity increase
Solution Approach 1:
The patent replaces the mechanical cooling system with an electrical modulation and lock-in detection system. The emitter modulates electromagnetic radiation at a specific frequency, and the lock-in detection electronically extracts the signal at this frequency, achieving high signal-to-noise ratio without physical cooling of the detector
Solution Approach 2:
The patent changes the operating parameters by using frequency-domain separation instead of temperature-based separation. The modulation unit varies the radiation intensity at a specific frequency, and the lock-in amplifier detects signals at this frequency, transforming the detection approach from thermal to electrical parameter control
2Measurement precision
If cooling is applied to the detector, then signal-to-noise ratio is improved, but manufacturing cost increases
Solution Approach 1:
The patent substitutes expensive mechanical cooling infrastructure with affordable electrical modulation and lock-in detection circuitry, dramatically reducing manufacturing costs while maintaining or improving signal-to-noise ratio performance
Solution Approach 2:
The patent employs inexpensive integrated circuit-based lock-in detection and modulation components that can be mass-produced, replacing costly and complex cooling systems with affordable electronic solutions
3Volume of moving object
If thermal detectors are used to avoid cooling, then device size is reduced, but detectivity decreases
Solution Approach 1:
The patent replaces thermal detection mechanisms with electrical field-based detection combined with frequency-domain filtering. The lock-in amplifier uses phase-sensitive detection at the modulation frequency to achieve high detectivity with miniaturized components
Solution Approach 2:
The patent employs periodic modulation of the emitter at a specific frequency, allowing the detector to operate continuously at room temperature while the lock-in detection synchronously integrates signals at this frequency, achieving high detectivity without thermal time constants
4Device complexity
If emitter operates at varying temperature, then device simplicity is maintained, but measurement accuracy decreases
Solution Approach 1:
The lock-in detection system provides feedback by continuously referencing the detected signal to the known modulation frequency, automatically compensating for temperature-induced variations in emitter performance and maintaining measurement accuracy without additional temperature control 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
The solution enhances accuracy and miniaturization of the spectrometer, enabling its integration into portable devices while reducing costs and thermal drift, and improving signal-to-noise ratio through lock-in detection and modulation techniques.
Implementation Method 1
The electrochromic material is configured to change its optical properties when a voltage is applied to the electrochromic material. For example, the transmission for electromagnetic radiation is changed when a voltage is applied to the electrochromic material.
Implementation Method 2
The optical filter can be configured to be transmissive for a predetermined wavelength range. Furthermore, the optical filter can exhibit a high absorption coefficient for electromagnetic radiation outside of the predetermined wavelength range.
Implementation Method 3
The optical detector is configured to detect electromagnetic radiation. For this purpose, the optical detector is configured to convert electromagnetic radiation reaching the optical detector into a modulated voltage signal.
Data Source
Figure 1A~1E
Figure 2A~2E
Figure 3~5
AI summary
A spectrometer (10) comprises an emitter (11) that is configured to emit electromagnetic radiation, a sample area (12) that is arranged at an outer face (13) of the spectrometer (10), a modulation unit (14) comprising an electrochromic material, an optical filter (15), an optical detector (16), an integrated circuit (17) that has a main plane of extension, and an optical path for electromagnetic radiation emitted by the emitter (11) towards the optical detector (16) via the sample area (12), the modulation unit (14) and the optical filter (15), wherein the electrochromic material is electrically connected with the integrated circuit (17), and the modulation unit (14) is configured to modulate electromagnetic radiation temporally. Furthermore, a method for detecting electromagnetic radiation is provided.