Prismatic Focus Corrector for Multispectral Imaging
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Solution Overview
Problem
Optical lenses exhibit longitudinal chromatic aberration, causing images to be in-focus for only a single wavelength, leading to out-of-focus and geometrically deformed images when capturing a broader spectrum of wavelengths, especially in multispectral or hyperspectral imaging.
Innovation Solution
Incorporating a focus corrector, such as a prismatic, stepped, or variable index of refraction corrector, within the optical path of the sensor array to refract light and align focal lengths of different wavelengths to a common focus point, accompanied by image processing to correct distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple lens is used, then the device complexity is low, but the image is in-focus for only a single wavelength and out-of-focus for other wavelengths
Solution Approach 1:
The patent divides the correction function into two separate components: a simple lens for capturing broad spectrum light and a focus corrector (prismatic element) that selectively corrects focus for different wavelengths. This segmentation allows each component to be optimized independently - the simple lens maintains low complexity while the separate corrector handles the precision focus adjustment.
Solution Approach 2:
The focus corrector acts as an intermediary element between the simple lens and the sensor array. It receives the light from the simple lens and modifies its path to compensate for chromatic aberration, enabling the system to achieve multi-wavelength focus without requiring the primary lens itself to be complex.
2Manufacturing precision
If chromatically corrected lenses are used, then the focus error is reduced in a certain wavelength band, but the lens becomes heavier and more expensive
Solution Approach 1:
The patent extracts the chromatic correction function from the main lens and implements it through a separate, lightweight focus corrector. This allows the primary lens to remain simple and lightweight while the correction functionality is provided by a smaller, dedicated prismatic element that adds minimal weight.
Solution Approach 2:
The focus corrector is implemented as a simple prismatic element that can be manufactured cost-effectively, replacing the need for expensive, heavy chromatically corrected lenses. The corrector uses basic optical principles (prism refraction) rather than complex multi-element lens designs, significantly reducing material and manufacturing costs.
3Manufacturing precision
If chromatically corrected lenses are used, then the focus error is reduced, but the lens becomes more expensive
Solution Approach 1:
The patent replaces expensive chromatically corrected lenses with a simple lens combined with an inexpensive prismatic focus corrector. The corrector can be manufactured using standard prism fabrication techniques, significantly reducing the overall system cost while maintaining the focus correction functionality.
Solution Approach 2:
The patent substitutes the complex mechanical lens design with a simpler system using a prismatic corrector that relies on geometric refraction principles. This substitution reduces manufacturing complexity and cost while achieving the same optical correction effect.
4Manufacturing precision
If a focus corrector is added to the optical path, then chromatic aberration is corrected, but the device complexity increases
Solution Approach 1:
The patent segments the optical system into a simple lens for light collection and a separate focus corrector for wavelength-specific focus adjustment. This modular approach allows the correction function to be added without redesigning the entire optical system, minimizing the increase in overall complexity.
Solution Approach 2:
The focus corrector applies localized optical correction by introducing wavelength-dependent refraction only where needed in the optical path. Rather than making the entire lens system complex, the corrector provides targeted correction for specific wavelength ranges, adding minimal complexity while achieving the desired precision.
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
Achieves focused hyperspectral or multispectral images with reduced chromatic aberration, using less expensive components than traditional chromatically corrected lenses, while maintaining suitable image quality.
Implementation Method 1
Incorporating a focus corrector, such as a prismatic, stepped, or variable index of refraction corrector, within the optical path of the sensor array to refract light and align focal lengths of different wavelengths to a common focus point
Data Source
Figure 1~2B
Figure 3A~4A
Figure 3B~4B
AI summary
Apparatuses, systems and methods for multispectral imaging are provided. The apparatuses and systems comprise a lens, an imaging device having a sensor array having a plurality of pixel sensors, and a focus corrector disposed between the lens and the sensor array, the focus corrector comprising sections of variable index of refraction configured to refract desired wavelengths of light outside a given spectral range and cause the desired wavelengths to converge onto the sensor array. A method for designing a focus corrector is also provided.