Metasurface Polarimetric Image Sensor for Higher Light Sensitivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing polarimetric image sensors face limitations in measuring light polarization efficiently due to bulky acquisition systems and reduced sensitivity caused by polarizer filters blocking part of the light signal.
Innovation Solution
A polarimetric image sensor is designed with a semiconductor substrate, featuring pixels with integrated photodetectors, polarization structures, and a two-dimensional metasurface that routes polarized radiation efficiently, reducing the need for external polarizers and enhancing light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a matrix of polarizing filters is placed opposite the image sensor to measure polarization information, then polarization measurement capability is improved, but the overall sensitivity and quantum efficiency of the acquisition system deteriorates due to light signal blocking
Solution Approach 1:
The sensor divides the pixel array into multiple groups, with each group containing pixels sensitive to different polarization states (0°, 45°, 90°, 135°). This segmentation allows simultaneous measurement of all polarization components without requiring sequential filtering, thereby maintaining high quantum efficiency while achieving complete polarization information.
Solution Approach 2:
The patent introduces a spectral dimension by using different wavelength ranges for different polarization measurements. The first set of pixels measures linear polarization in a first wavelength range, while the second set measures linear polarization in a second wavelength range, enabling polarization measurement without traditional blocking filters.
2Loss of information
If successive images are acquired with different polarizers to measure multiple polarization states, then complete polarization information is obtained, but the system becomes bulky and complex due to required mechanical components
Solution Approach 1:
The patent merges multiple polarization measurement functions into a single sensor array by integrating polarization-sensitive photodetectors directly in the pixel structure. This eliminates the need for separate polarizer components and mechanical rotation stages, significantly reducing system complexity and bulkiness while maintaining complete polarization measurement capability.
Solution Approach 2:
The sensor structure itself provides the polarization discrimination function through the inherent properties of the photodetectors and associated optical elements integrated within each pixel. Each pixel group is self-configured to detect specific polarization states, eliminating the need for external polarizing optics and mechanical adjustment mechanisms.
3Measurement precision
If multiple polarizers are used to capture different polarization states simultaneously, then polarization measurement accuracy is improved, but the acquisition system becomes less efficient due to light loss through multiple filters
Solution Approach 1:
The pixel array is segmented into distinct groups, each optimized for measuring specific polarization states. This allows direct detection of polarized light without requiring multiple sequential filter applications, thereby maintaining high acquisition efficiency while achieving accurate polarization measurement across all states.
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 design improves the sensitivity and efficiency of polarimetric image acquisition by directly routing polarized light to photodetectors, reducing bulkiness and increasing the overall quantum efficiency of the sensor.
Implementation Method 1
a polarizing filter disposed on the side of an illumination face of the photodetectors, the filter comprising, for each pixel, a polarization structure
Implementation Method 2
a plurality of pixels each comprising a photodetector formed in the semiconductor substrate
Implementation Method 3
a polarization router comprising a two-dimensional metasurface disposed on the side of the polarizing filter opposite the photodetectors, the metasurface comprising a two-dimensional network of pads
Data Source
Figure 1A~1B
Figure 2~3
Figure 4A~4B
AI summary
The present description relates to a polarimetric image sensor (400) formed in and on a semiconductor substrate, the sensor comprising: - a plurality of pixels (P) each comprising a photodetector formed in the semiconductor substrate; - a polarization router comprising a two-dimensional metasurface (MS) disposed on the side of an illumination face of the photodetectors, the metasurface comprising a two-dimensional array of dots; and - a plurality of first microlenses (401) extending opposite a pair of adjacent pixels of the sensor.