Layered Color-Separating Lens Array for Image Sensors
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Solution Overview
Problem
Image sensors using color filters suffer from low light utilization efficiency, with only about 33% of incident light being transmitted and the rest absorbed, leading to significant light loss.
Innovation Solution
An image sensor utilizing a color separating lens array that separates and condenses light of different wavelengths onto specific pixels using a spacer layer and multiple lens layers with nanoposts, enhancing light utilization efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a color filter is used to sense light color, then the image sensor can distinguish different wavelengths, but light utilization efficiency deteriorates because most incident light is absorbed
Solution Approach 1:
The color separating lens array segments incident light by wavelength, with each lens focusing a specific wavelength range onto corresponding pixels. This segmentation approach replaces the absorbing color filter mechanism with a directional focusing mechanism, allowing different wavelength components to be spatially separated and directed to appropriate photodetectors without absorption losses.
Solution Approach 2:
The color separating lens array acts as an intermediary optical element between the incident light and the pixel array. Instead of using color filters that absorb light to achieve wavelength discrimination, the lens array mediates the light-pixel interaction by focusing specific wavelengths to specific pixels based on optical focusing principles, thereby maintaining high light utilization efficiency.
2Measurement precision
If a color filter absorbs light to achieve color separation, then wavelength discrimination is improved, but light loss increases significantly
Solution Approach 1:
The lens array segments the incident light spectrum into multiple wavelength components, with each lens element optimized to focus a specific wavelength range. This spatial segmentation replaces the spectral filtering approach, achieving wavelength discrimination through directional focusing rather than absorption, thereby minimizing light loss.
Solution Approach 2:
The patent replaces the chemical/absorptive mechanism of color filters with an optical/mechanical focusing mechanism. The lens array uses refractive optics to physically direct different wavelength components to different pixels, substituting the absorption-based wavelength discrimination with a focusing-based approach that preserves light energy.
3Measurement precision
If multiple lens layers are added to improve color separation, then wavelength discrimination is enhanced, but device complexity increases
Solution Approach 1:
The lens array is segmented into multiple functional layers, with each layer containing lenses optimized for specific wavelength ranges. This layered segmentation allows progressive refinement of wavelength discrimination, with each layer contributing to separating specific spectral components, achieving high-color accuracy through modular architectural design.
Solution Approach 2:
The patent transitions from a single-plane lens arrangement to a multi-layer three-dimensional structure. By stacking lens layers at different depths, the system exploits the vertical dimension to achieve enhanced spectral discrimination. Each layer adds a dimension of optical path control, enabling more sophisticated wavelength separation without requiring excessive lateral complexity.
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
Improves light utilization efficiency and color reproductivity by effectively directing light to respective pixels, reducing light loss and enhancing image quality.
Implementation Method 1
a color separating lens array on the spacer layer, the color separating lens array being configured to condense the light of the first wavelength incident on the color separating lens array toward the first pixel
Implementation Method 2
the color separating lens array being configured to condense the light of the first wavelength incident on the color separating lens array toward the first pixel
Data Source
AI summary
Provided is an image sensor including a color separating lens array. The image sensor includes: a sensor substrate including a first pixel configured to sense light of a first wavelength and a second pixel configured to sense light of a second wavelength; a transparent spacer layer on the sensor substrate; and a color separating lens array on the spacer layer, wherein the color separating lens array condenses the light of the first wavelength toward the first pixel, and includes a first lens layer on the spacer layer, a second lens layer on the first lens layer, and an etch prevention layer between the first lens layer and the second lens layer.