Irregular Multispectral Color Filter for Compact High-Sensitivity Imaging
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Solution Overview
Problem
Existing methods for acquiring multiband images face challenges in achieving high sensitivity and wavelength resolution while maintaining a compact system size, as they either reduce incident light or require large multi-imaging optical systems.
Innovation Solution
The use of an image sensor with a color filter comprising multiple filter segments, each with unique spectral transmittances, arranged irregularly to increase incident light and facilitate wavelength separation, allowing for high sensitivity and compact system design through single image capturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single wavelength band is assigned to each pixel through array of color filters, then wavelength resolution is improved, but incident light amount decreases and image capturing sensitivity decreases
Solution Approach 1:
The color filter is divided into multiple filter segments (first to Z-th filter segments) with different spectral transmittances, where each segment corresponds to one pixel. This segmentation allows each pixel to receive light from multiple wavelength bands simultaneously, increasing incident light amount while maintaining wavelength resolution through the distinct spectral characteristics of each filter segment.
Solution Approach 2:
Each pixel is equipped with a color filter that has multiple filter segments with different spectral transmittances, enabling each pixel to perform multiple functions by receiving light from multiple wavelength bands. This multi-functionality increases the incident light amount for each pixel while maintaining the ability to distinguish different wavelength bands through the unique spectral characteristics of each filter segment.
2Measurement precision
If a multi-imaging optical system is used to acquire multiband images, then wavelength resolution is improved, but system size increases
Solution Approach 1:
Multiple filtering functions that would traditionally require separate imaging optical systems are merged into a single color filter with multiple filter segments. This consolidation allows a single image sensor to capture multiband images by having each pixel receive light from multiple wavelength bands simultaneously, significantly reducing system size while maintaining wavelength resolution through the distinct spectral transmittances of the filter segments.
Solution Approach 2:
A single image sensor with color filters having multiple filter segments performs the function of multiple imaging systems. Each filter segment with its unique spectral transmittance enables the system to capture different wavelength bands through a single optical path, achieving multi-functionality in a compact configuration that eliminates the need for multiple separate imaging systems.
3Measurement precision
If filter segments with different spectral transmittances are arranged irregularly, then wavelength separation is improved, but device complexity increases
Solution Approach 1:
The filter segments with different spectral transmittances are arranged irregularly rather than in a regular pattern. This asymmetric arrangement improves wavelength separation by ensuring that adjacent pixels receive different combinations of wavelength bands, enhancing the ability to distinguish between different wavelength bands through the unique spectral signatures captured at each pixel location.
Solution Approach 2:
Each filter segment is designed with specific local spectral transmittance characteristics tailored to its position in the irregular arrangement. This local quality approach optimizes wavelength separation by assigning filter segments with appropriate spectral properties to specific locations, ensuring that the irregular pattern effectively captures diverse wavelength information across the image sensor array.
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 enables the acquisition of highly sensitive multiband images with increased incident light and effective wavelength separation, maintaining system compactness and performance without the need for an optical low-pass filter.
Implementation Method 1
an image sensor including M×N pixels and configured to photoelectrically convert an object image
Implementation Method 2
a color filter disposed on an object side of the image sensor, and including a plurality of filter segments. Each filter segment corresponds to one of the pixels of the image sensor. The plurality of filter segments include first to Z-th filter segments having spectral transmittances different from each other
Data Source
AI summary
An image-pickup unit includes an image sensor and a color filter. Each filter segment of the color filter corresponds to one of a plurality of pixels of the image sensor, and the plurality of filter segments include first to Z-th (2L−1≦Z≦2L, where L is an integer equal to or larger than four) filter segments having spectral transmittances for transmitted wavelength bands different from each other among light from an object. Each pixel of the image sensor receives light of a plurality of wavelength bands. The plurality of filter segments are irregularly disposed.