Imaging Optical System Multi-Wavelength Pupil Segmentation
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Solution Overview
Problem
Current multi-band cameras face challenges in capturing images across different wavelength ranges with high focusing accuracy due to axial chromatic aberration, which is not effectively addressed by existing technologies.
Innovation Solution
The imaging device incorporates an imaging optical system with distinct pupil regions for different wavelength ranges, utilizing aberrations such as spherical, coma, and astigmatism to offset axial chromatic aberration, combined with bandpass and polarization filters to process signals from multiple pixels, thereby improving focusing accuracy across various wavelength ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a multi-band camera uses a conventional imaging optical system to capture images in multiple wavelength ranges, then it can obtain spectral information, but axial chromatic aberration causes focusing accuracy to deteriorate across different wavelengths
Solution Approach 1:
The imaging optical system is segmented into multiple pupil regions (first pupil region, second pupil region, etc.), each corresponding to different wavelength ranges. This segmentation allows independent optimization of optical paths for different wavelengths, enabling the system to capture multiple wavelength ranges while maintaining focusing accuracy by reducing axial chromatic aberration through the specific arrangement of pupil regions
Solution Approach 2:
Different regions of the pupil are assigned different optical characteristics to address local requirements. The first pupil region is optimized for first wavelength range with specific aberration characteristics, while the second pupil region is optimized for second wavelength range. This local quality differentiation allows each wavelength range to be imaged with appropriate focus, resolving the axial chromatic aberration problem while maintaining multi-wavelength capability
2Measurement precision
If axial chromatic aberration is corrected using conventional methods, then focusing accuracy for a single wavelength range can be improved, but the ability to simultaneously capture multiple wavelength ranges with equal accuracy deteriorates
Solution Approach 1:
The imaging optical system achieves multi-functionality by incorporating multiple pupil regions that can simultaneously handle different wavelength ranges. Each pupil region functions as a dedicated optical path for its corresponding wavelength range, yet all regions work together within a single imaging system to achieve both high focusing accuracy and multi-wavelength simultaneous capture capability
3Device complexity
If the imaging optical system uses a single pupil region for all wavelengths, then the device complexity is reduced, but the focusing accuracy across different wavelength ranges deteriorates due to uncorrected axial chromatic aberration
Solution Approach 1:
Instead of adding complex optical elements in the traditional optical path direction, the invention introduces a new dimension of spatial distribution by dividing the pupil into multiple regions. This dimensional approach to organizing optical paths allows the system to maintain relatively simple overall structure while achieving improved focusing accuracy through the strategic arrangement of first pupil region, second pupil region, and their corresponding wavelength ranges
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 allows for simultaneous capture of images in multiple wavelength ranges with reduced axial chromatic aberration, enhancing focusing accuracy and image quality by leveraging the relationship between pupil region positions and aberrations in the imaging optical system.
Implementation Method 1
an axial chromatic aberration of the imaging optical system due to a difference between the first wavelength range and the second wavelength range is reduced based on a relationship between an aberration other than the axial chromatic aberration of the imaging optical system and positions of the first pupil region and the second pupil region
Implementation Method 2
the aberration other than the axial chromatic aberration of the imaging optical system is a coma aberration
Implementation Method 3
the aberration other than the axial chromatic aberration of the imaging optical system is an astigmatism
Implementation Method 4
an axial chromatic aberration of the imaging optical system due to a difference between the first wavelength range and the second wavelength range is reduced
Implementation Method 5
combined with bandpass and polarization filters to process signals from multiple pixels
Implementation Method 6
combined with bandpass and polarization filters to process signals from multiple pixels
Implementation Method 7
an imaging element which includes a first pixel receiving the light passing through the first pupil region and a second pixel receiving the light passing through the second pupil region
Data Source
AI summary
Provided are an imaging device which can simultaneously capture images in different wavelength ranges and can improve a focusing accuracy of each image, an imaging optical system, and an imaging method. An imaging device (1) includes an imaging optical system (10) which has a first pupil region for passing light in a first wavelength range and a second pupil region for passing light in a second wavelength range, in which an axial chromatic aberration of the imaging optical system (10) is reduced based on a relationship between an aberration other than the axial chromatic aberration of the imaging optical system (10) and positions of the first pupil region and the second pupil region in the imaging optical system (10), an imaging element (100) which includes a first pixel receiving the light passing through the first pupil region in the imaging optical system (10) and a second pixel receiving the light passing through the second pupil region in the imaging optical system (10), and a signal processing unit (200) which processes a signal output from the imaging element (100), and generates each of a first image of the first wavelength range and a second image of the second wavelength range based on an output signal of the first pixel and an output signal of the second pixel.