Metalens Error Compensation via Segmented Illumination
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Solution Overview
Problem
Metalenses suffer from focusing inefficiencies, particularly due to 2nd order light, which results in poor image quality and the formation of undesirable bright spots on image sensors.
Innovation Solution
An imaging system and method that incorporate error compensation by partially illuminating the field of view during image capture, allowing for the reduction and control of 2nd order light, and generating output images using various combinations of image segments to minimize or eliminate 2nd order light artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If metalenses are used to focus light onto image sensors, then miniaturization and simplification of optics is achieved, but 2nd order light causes unfocused light and bright spots on image sensors resulting in poor image quality
Solution Approach 1:
The field of view is divided into multiple image segments, where certain segments capture 2nd order light while others do not. By selectively combining image segments from multiple images, the patent separates and eliminates 2nd order light artifacts while preserving the desired focused image content.
Solution Approach 2:
The patent employs periodic illumination patterns where different portions of the field of view are illuminated in alternating time intervals. This periodic action allows capture of multiple images with different 2nd order light distributions, enabling subsequent computational elimination of the artifacts.
2Illumination intensity
If 2nd order light is present in captured images, then light intensity is increased, but visual artifacts in the form of bright spots appear on image sensors
Solution Approach 1:
The patent converts the harmful 2nd order light into a useful signal by having it selectively illuminate specific image segments in specific images. This allows the 2nd order light to be identified and eliminated through computational processing, transforming the artifact problem into a solvable pattern recognition task.
Solution Approach 2:
The patent dynamically controls illumination patterns across multiple time intervals, causing 2nd order light to appear in different image segments at different times. This dynamic approach enables the system to distinguish 2nd order light from desired image content through temporal variation analysis.
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 proposed solution effectively compensates for focusing inefficiencies in metalenses, resulting in high-quality output images with minimal visual artifacts, thereby enabling the use of metalenses in various imaging systems.
Implementation Method 1
a metalens employs metasurfaces having nanostructures to focus light
Implementation Method 2
A first order focal length f of the metalens focuses the light correctly on the plane 106 of the image sensor
Data Source
AI summary
Disclosed is imaging system (200) including controllable light source; image sensor; metalens to focus light onto IS; and processor(s). The processor(s) is configured to control CLS to illuminate given part of field of view of IS at a first instant, while controlling IS to capture first image (FImg). The image segment(s) represent a given part as illuminated and remaining image segment(s) represent a remaining part of the FOV as non-illuminated. The processor controls the CLS to illuminate the remaining part at second instant, while controlling IS to capture a second image whose image segment(s) represents a given part as non-illuminated and a remaining image segment(s) represents a remaining part as illuminated. Output image is generated based on: (i) image segment(s) of FImg and remaining image segment(s) of SImg, and/or (ii) remaining image segment(s) of FImg and image segment(s) of SImg.