Spectral Sensor System with Spatially Modified Filter Cavities
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Solution Overview
Problem
Spectral image sensors using interference-based filters, such as Fabry-Perot filters, face performance issues due to non-ideal angular responses, leading to unstable spectral measurements and reduced accuracy, particularly when high chief ray angle lenses are used, causing shifts in center wavelengths and non-uniform angularity across the sensor array.
Innovation Solution
The implementation of a pre-compensated filter array with varying cavity thicknesses and a reverse telecentric lens system to stabilize filter responses and maintain uniform angularity, using a mosaic pattern of Fabry-Perot filters with thicker cavities at the edges to compensate for the blue shift caused by high chief ray angles, and integrating micro-lenses to control the angle of incidence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If interference-based filters are used in spectral sensors, then controlled light wavelengths can be achieved, but non-ideal angular responses cause shifts in center wavelengths and reduce measurement accuracy
Solution Approach 1:
The patent applies local quality by varying the cavity thickness of interference filters at different spatial locations across the sensor array. Filters at edge positions have different thicknesses compared to center filters, creating location-specific optical properties that compensate for position-dependent angular response variations. This ensures each filter maintains its designed center wavelength despite oblique incident angles at different sensor locations.
Solution Approach 2:
The patent changes the physical parameter of cavity thickness in the interference filters to compensate for angular response issues. By adjusting this parameter spatially across the filter array, the system maintains stable center wavelengths and spectral response characteristics even when subjected to varying incident angles from high chief ray angle lenses.
2Volume of moving object
If high chief ray angle lenses are used, then device miniaturization is enabled, but non-uniform angularity across the sensor array causes spectral impurities and reduces accuracy
Solution Approach 1:
The patent implements local quality by creating position-dependent filter characteristics across the sensor array. Each filter's cavity thickness is specifically tailored to its location, compensating for the non-uniform angular distribution of light from high chief ray angle lenses. This localized optimization maintains spectral accuracy throughout the entire array despite the lens-induced angular variations.
Solution Approach 2:
The patent applies preliminary anti-action by pre-compensating for the expected angular response issues through spatially varying filter design. Before light reaches the sensors, the filter array is configured to counteract the blue shift and spectral impurities that would otherwise be caused by oblique incident angles from compact high CRA lenses, thereby maintaining measurement accuracy in miniaturized systems.
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 ensures a stable and uniform spectral response across the sensor array, reducing spectral impurities and improving accuracy by maintaining consistent filter center wavelengths, even at oblique angles, thereby enhancing the performance of spectral image sensors in applications like mobile devices and industrial inspections.
Implementation Method 1
Interference-based filters, such as Fabry-Perot filters, when used in conjunction with spectral sensors have been shown to be capable of providing controlled light wavelengths
Implementation Method 2
spectral sensors using interference-based filters
Implementation Method 3
reverse telecentric lens system to stabilize filter responses and maintain uniform angularity
Implementation Method 4
an optical element configured to limit an angle of incidence of light passing through the array of optical filters
Data Source
AI summary
A sensor system comprises a plurality of sets optical sensors arranged on an integrated circuit, the plurality of sets optical sensors having a respective top surface. The sensor system further comprising an interface between the plurality of optical sensors and a processing device configured to transmit information there between and an array of optical filters having a respective bottom surface and a respective top surface, where the bottom surface of the optical filter array is located proximal to the top surface of the plurality of sets optical sensors and each optical filter of the optical filter array is configured to pass a target wavelength range of light to a set of optical sensors. The processor is configured to receive an output from each optical sensor in a set of optical sensors and determine a corrected filter response for the set of optical sensors using crosstalk from light transmitted through optical filters adjacent to the set of optical sensors.