Diffraction Grating Spectral Imaging Optical System
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Solution Overview
Problem
Existing image pickup devices for spectral imaging, such as medical endoscopes and industrial inspection devices, face challenges in achieving high-resolution spectral imaging while also providing color images, as they either lack color object images or require additional components that increase device size.
Innovation Solution
Incorporating a diffraction element in the optical path of the observation optical system, which separates zero-order light for color imaging and ±1st-order light for spectral imaging, allowing both to be imaged on the same image pickup surface without overlap, enabling simultaneous high-resolution spectral and color image observation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a spectroscopic element is used to obtain high-resolution spectral images, then spectral resolution is improved, but color object images cannot be obtained and device size increases
Solution Approach 1:
The patent segments the light from a single object point into multiple spectral components using a diffraction grating. The zero-order light forms a color image while the ±1st-order diffracted lights form spectral images at different positions on the image pickup surface, allowing simultaneous acquisition of both color and spectral information without additional devices
Solution Approach 2:
The diffraction grating serves multiple functions simultaneously: it acts as a dispersion element for spectral analysis while also allowing the zero-order light to pass through for color imaging. This multi-functionality eliminates the need for separate spectroscopic and color imaging systems, reducing overall device size
2Loss of information
If a rotating filter or variable transmittance element is used to obtain spectral images, then spectral information is obtained, but high-resolution spectral extraction cannot be achieved
Solution Approach 1:
The patent replaces mechanical filtering systems (rotating filters, variable transmittance elements) with a diffraction-based optical system. The diffraction grating spatially separates wavelengths optically, achieving high spectral resolution without mechanical movement or complex filtering mechanisms
Solution Approach 2:
The patent changes the approach from temporal multiplexing (rotating filters switching wavelengths over time) to spatial multiplexing (diffraction grating separating wavelengths simultaneously in space). This parameter change enables high-resolution spectral extraction while maintaining continuous illumination and imaging
3Adaptability or versatility
If additional image pickup optical system is provided to obtain color images, then color imaging capability is improved, but device size increases
Solution Approach 1:
The patent merges the spectroscopic imaging function and color imaging function into a single optical path using a diffraction grating. The zero-order light from the diffraction grating provides color imaging while the diffracted orders provide spectral imaging, eliminating the need for separate optical systems
Solution Approach 2:
The single optical system with diffraction grating performs both color imaging and spectral imaging functions simultaneously. The same image pickup element captures both zero-order color images and ±1st-order spectral images, making the system universal and eliminating the need for additional color imaging hardware
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 solution allows for a compact image pickup apparatus that can provide both morphological and spectral information of an object, enabling detailed analysis and inspection without increasing the device size, while preventing flare in the light-receiving areas.
Implementation Method 1
a diffraction element (3) provided in the optical path of an observation optical system (2)
Data Source
AI summary
An image pickup apparatus has a construction in which a diffraction element is provided in an observation optical system. Zero-order light that is transmitted straight through the diffraction element and one of the +1st-order diffracted light and the −1st-order diffracted light that is diffracted by the diffraction element are imaged onto an image pickup surface of an image pickup apparatus. The imaging areas of the zero-order light and one of the +1st-order diffracted light and the −1st-order diffracted light that is diffracted by the diffraction element do not overlap on the image pickup surface of the image pickup apparatus. With this construction, a small image pickup apparatus that provides a high-resolution spectral image and a color image of an object can be obtained.