Color-Routing Nanostructures for Low-Loss Image Sensor Pixels
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Solution Overview
Problem
Conventional image sensors suffer from low light use efficiency due to the absorption of light by color filters, especially when pixel sizes are reduced to the micrometer level, leading to increased noise vulnerability.
Innovation Solution
The implementation of a color-routing element with nanostructures that separate colors without absorbing or blocking light outside a target wavelength range, allowing each color to focus on a target pixel, along with a method of manufacturing this element by reflecting a color-routing figure of merit and process errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a color filter is used to detect color, then color detection function is achieved, but light use efficiency deteriorates due to absorption of light outside target wavelength range
Solution Approach 1:
The patent extracts the color detection function from the traditional color filter and relocates it to the photodiode layer. By removing the color filter that absorbs light, the system achieves higher light use efficiency while maintaining color detection capability through spatial separation of colors via the microlens array.
Solution Approach 2:
The patent introduces a microlens array as an intermediary component between the incident light and the photodiode. This microlens array performs spectral separation by focusing different wavelengths to different regions of the photodiode, enabling color detection without light absorption losses.
2Measurement precision
If pixel size is reduced to micrometer level, then resolution is improved, but light transmission through color filter further decreases leading to increased noise vulnerability
Solution Approach 1:
The patent removes the color filter component entirely, allowing micrometer-level pixels to receive maximum light without filtration losses. Color detection is achieved through the microlens array's spectral separation function, enabling high resolution with improved light transmission efficiency.
3Loss of energy
If a color-routing element with optimized nanostructures is manufactured, then color-routing efficiency is improved, but manufacturing complexity increases due to need to reflect process errors
Solution Approach 1:
The patent performs preliminary simulation and optimization of the microlens array parameters before manufacturing. By calculating optimal lens shapes, sizes, and arrangements in advance using electromagnetic field simulations, the system achieves high color-routing efficiency while simplifying the actual manufacturing process.
Solution Approach 2:
The patent uses simulation models to create virtual copies of the microlens array design and iteratively optimizes parameters in the virtual environment. This virtual prototyping allows thorough optimization without incurring the full complexity of physical manufacturing iterations.
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 use efficiency and color-routing efficiency while providing robustness against process errors, resulting in improved image sensor performance.
Implementation Method 1
The microlens array focuses light onto the photodiode
Implementation Method 2
the color filter absorbs light of colors other than the light of the corresponding color
Implementation Method 3
uses a color-routing element including nanostructures (or nano posts) so as to separate colors
Implementation Method 4
uses a color-routing element including nanostructures (or nano posts) so as to separate colors so that each color gathers at a focus of a target pixel
Data Source
AI summary
A method of manufacturing a color-routing element, may include: generating an initial pattern; performing blurring on the initial pattern to generate a reference pattern; performing edge detection on the reference pattern to generate at least one comparison pattern reflecting a process error; performing a simulation to obtain at least one color-routing figure of merit based on the reference pattern and the at least one comparison pattern; updating the initial pattern based on a calculation result of the at least one color-routing figure of merit; generating the updated initial pattern as a target pattern of the color-routing element; and manufacturing the color-routing element based on the target pattern.