Color Image Sensor Micro-Spectroscopy for Low-Polarization RGB Separation
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Solution Overview
Problem
Existing color image-capture elements face challenges in light utilization efficiency and manufacturing complexity due to polarization dependency and high costs associated with microstructure-based color separation methods, particularly when separating incident light into three wavelength ranges.
Innovation Solution
A color image-capture element utilizing micro-spectroscopic elements with constant thickness columnar structures that spatially separate incident light into three wavelength ranges, reducing polarization dependency and manufacturing complexity by using a two-dimensional array of micro-lenses and micro-spectroscopic elements with phase delay effects to direct light to adjacent pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If color filters are used for color separation, then color information can be obtained, but light utilization efficiency decreases to about 30%
Solution Approach 1:
The patent replaces the mechanical/optical color filter system with a computational color separation system. Instead of using physical color filters that absorb or reflect light, the invention uses a color separation unit that performs matrix calculations on signals from multiple photoelectric conversion elements to derive color information, thereby eliminating light loss from absorption and reflection.
Solution Approach 2:
The patent changes the approach from optical parameter-based color separation (using color filters with specific transmission characteristics) to mathematical parameter-based color separation (using matrix calculations on photoelectric signals). This allows recovery of light that would otherwise be lost, improving light utilization efficiency while maintaining color information accuracy.
2Loss of energy
If micro-prism or dichroic mirror spectroscopic elements are used, then light utilization efficiency improves, but integration on photoelectric conversion element becomes difficult
Solution Approach 1:
The patent extracts the color separation function from complex optical components (micro-prisms, dichroic mirrors) and relocates it to a computational processing unit. This allows the photoelectric conversion element to maintain a simple, flat structure suitable for integration, while color separation functionality is achieved through signal processing rather than complex optical path manipulation.
Solution Approach 2:
The patent introduces a color separation unit as an intermediary between the photoelectric conversion elements and the color image output. This intermediary performs matrix calculations to separate color information from the combined signals, replacing the need for complex optical intermediaries like dichroic mirrors while maintaining high light utilization efficiency.
3Loss of energy
If conventional spectroscopic elements with different structure thickness are used, then color separation into wavelength ranges is achieved, but manufacturing cost increases
Solution Approach 1:
The patent makes all photoelectric conversion elements identical in structure, with each element capable of converting all incident light wavelengths into electrical signals. This universal design simplifies manufacturing by eliminating the need to produce multiple types of spectroscopic elements with different thicknesses, while color separation is achieved computationally through matrix operations on the unified signal set.
4Measurement precision
If pixel miniaturization is implemented, then resolution improves, but quantity of light received by one pixel decreases
Solution Approach 1:
The patent uses multiple identical photoelectric conversion elements (at least three per pixel group) that all receive and convert the same incident light. By having multiple copies of the photoelectric conversion function, the system ensures that even miniaturized pixels receive sufficient light quantity, as each element contributes to the overall signal while maintaining the ability to perform color separation computationally.
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 enhances light utilization efficiency and reduces manufacturing costs while minimizing polarization dependency, allowing for high-sensitivity color image capture with improved color reproducibility.
Implementation Method 1
A color image-capture element according to the present invention separates incident light into three wavelength ranges using micro-spectroscopic elements having a two-dimensional array of micro-lenses and microstructures with constant thickness
Data Source
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Figure 3(a)~3(b)
AI summary
Provided is a highly-sensitive color image-capture element and an image capture device that can be simply manufactured, have little polarization dependency, and have micro-spectroscopic elements capable of separating incident light into three wavelength ranges integrated facing a two-dimensional pixel array. An image capture element 100 has a transparent layer 111 having a low refractive index made of SiO2 or the like and a plurality of micro-lenses 103 laminated on a two-dimensional pixel array in which pixels 102 each including a photoelectric conversion element are disposed in an array. Inside the transparent layer 111 having the low refractive index, micro-spectroscopic elements 101 composed of a plurality of microstructures having constant thickness (length in a direction perpendicular to the two-dimensional pixel array) formed of a material such as SiN having a higher refractive index than that of the transparent layer 111 is embedded.