Optical Sensor Array Wavelength Assignment via Photocurrent Ratios
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Solution Overview
Problem
Existing techniques for measuring spectral emission characteristics of optical radiation often provide only global or averaged measurements, making it difficult to assign a specific wavelength to a measured photocurrent, especially in cases with multiple emission peaks or ambient light detection.
Innovation Solution
The use of optical radiation sensors and detection techniques that involve an array of light sensitive elements with stacked photosensitive regions and optical filters configured to allow only narrow parts of the optical spectrum to pass, allowing for the calculation of photocurrent ratios and assignment of specific wavelengths to incident radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an array of photodiodes is used to measure incident light of various wavelengths, then global or averaged measurements can be obtained, but it becomes impossible to assign a particular photocurrent value to a unique wavelength
Solution Approach 1:
The patent divides the detection system into multiple photodiodes, each equipped with a specific optical filter that allows only a narrow wavelength band to pass. This segmentation enables each photodiode to measure a specific wavelength range, thereby preserving wavelength-specific information that would otherwise be lost in global measurements.
Solution Approach 2:
Each photodiode is assigned a unique optical filter with specific wavelength transmission characteristics, creating local quality differences across the array. This allows different regions of the photodiode array to detect different wavelength bands, enabling precise wavelength identification through spatial differentiation.
2Adaptability or versatility
If standard RGB filters are used in the sensor, then the sensor can detect red, green and blue light, but it will be unable to detect emission peaks outside these filter ranges such as sodium-vapor lines near 589 nm
Solution Approach 1:
The patent employs an array of photodiodes with multiple optical filters including but not limited to standard RGB filters. This multi-functional configuration enables the sensor to detect a broad spectrum of wavelengths, including emission peaks outside conventional RGB ranges such as sodium-vapor lines, while maintaining detection capability across the visible spectrum.
3Measurement precision
If optical filters are used to allow only narrow parts of the optical spectrum to pass, then specific wavelengths can be assigned to photocurrents, but the device complexity increases
Solution Approach 1:
The patent combines multiple optical filters with corresponding photodiodes in an integrated array structure. By merging the filter-diode pairs into a unified sensor array, the system achieves precise wavelength assignment through the combination of spectral filtering and spatial detection, managing complexity through systematic integration.
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 approach enables accurate determination of spectral emission characteristics of optical radiation, allowing for precise wavelength assignment even in complex light sources, thereby improving measurement accuracy and applicability across various applications.
Implementation Method 1
Optical filters are disposed over the array of light sensitive elements, wherein the optical filters are configured to allow only respective narrow parts of the optical spectrum to pass to different ones of the light sensitive elements
Implementation Method 2
an array of light sensitive elements composed at least in part of stacked first and second photosensitive regions whose optical responsivity characteristics differ from one another
Data Source
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Figure 5~6A
AI summary
The present disclosure describes optical radiation sensors and detection techniques that facilitate assigning a specific wavelength to a measured photocurrent. The techniques can be used to determine the spectral emission characteristics of a radiation source. In one aspect, a method of determining spectral emission characteristics of incident radiation includes sensing at least some of the incident radiation using a light detector having first and second photosensitive regions whose optical responsivity characteristics differ from one another. The method further includes identifying a wavelength of the incident radiation based on a ratio of a photocurrent from the first region and a photocurrent from the second region.