Image-Capture Element With Embedded Micro-Spectroscopy for Low-Light Imaging

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Solution Overview

Problem

Existing image capture elements face challenges with low light utilization efficiency due to color filters absorbing or reflecting unnecessary wavelengths, leading to sensitivity limitations, especially with pixel miniaturization, and existing spectroscopic elements have manufacturing complexities and polarization dependency.

Innovation Solution

A color image-capture element with a two-dimensional pixel array and integrated micro-spectroscopic elements that use columnar structures with symmetrical surfaces to separate incident light into three wavelength ranges, reducing polarization dependency and simplifying manufacturing.

Engineering Contradictions & Design Principles

VSEngineering 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%

Engineering Contradiction:

Improvelight utilization efficiencyVSAvoidmanufacturing simplicity

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The patent changes the fundamental parameter of color separation from absorption-based (color filters) to refraction-based (micro-prisms). This parameter change enables near-100% light utilization by directing different wavelengths to different pixels without absorption losses, while maintaining manufacturing feasibility through standard semiconductor fabrication processes

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the optical filtering mechanism (color filters that absorb light) with a geometric optics mechanism (micro-prisms that refract and redirect light). This substitution eliminates the energy loss inherent in absorption-based color separation while achieving the same color information extraction goal

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Area of moving object

If pixel size is reduced for miniaturization, then device density increases, but quantity of light received per pixel decreases

Engineering Contradiction:

Improvepixel sizeVSAvoidlight quantity per pixel

Core Design Contradiction:

Area of moving objectVSLoss of energy

Solution Approach 1:

By changing from absorption-based to refraction-based color separation, the patent enables small pixels to receive maximum light quantities. The micro-prism structure ensures that nearly all incident light (接近100%) is directed to the photoelectric conversion element, compensating for the reduced pixel area in miniaturized devices

Inventive Principle:

Principle #35Parameter changes

3Loss of energy

If conventional spectroscopic elements are used, then light utilization efficiency improves, but manufacturing complexity and polarization dependency increase

Engineering Contradiction:

Improvelight utilization efficiencyVSAvoidmanufacturing complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent simplifies the spectroscopic element design by using uniform micro-prism structures with consistent height and geometry, eliminating the need for complex multi-layer or variable-structure designs. This uniform structure achieves high light utilization efficiency while being compatible with standard semiconductor manufacturing processes

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The micro-prism structure uses asymmetric geometry (triangular cross-section) to achieve wavelength-dependent refraction. The asymmetric shape creates different phase delays for different wavelengths, enabling color separation without requiring complex symmetric multi-layer structures or polarization-sensitive components

Inventive Principle:

Principle #4Asymmetry

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

The solution achieves high light utilization efficiency with minimal light loss and improved sensitivity by spatially separating light into three wavelength regions without polarization dependency, using easily manufacturable micro-spectroscopic elements.

Implementation Method 1

inside the micro-beam structures and around them, phase delay effects perceived by the incident light are greatly different in one wavelength range and almost equal in the other wavelength range

Methodology Applied

Scientific EffectPhase delay effect:

Implementation Method 2

a photoelectric conversion element such as a CCD (Charge Coupled Device) sensor or a COMS (Complementary Metal Oxide Semiconductor) sensor

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS20250261456A1Image-capture element and image capture device

Publication Date: 2025.08.14 NT T INC

AI summary

Provided is a highly-sensitive 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 pixel array. An image capture element has a transparent layer having a low refractive index made of SiO2 or the like and a plurality of micro-lenses laminated on a pixel array in which pixels each including a photoelectric conversion element are disposed in an array. Inside the transparent layer having the low refractive index, micro-spectroscopic elements composed of a plurality of microstructures having constant thickness (length in a direction perpendicular to the pixel array) formed of a material such as SiN having a higher refractive index than that of the transparent layer is embedded.