Color-Separating Lens Array for Low-Loss Image Sensor Pixels
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Solution Overview
Problem
Conventional image sensors using color filters suffer from low light utilization efficiency, with only about 33% of incident light being transmitted, resulting in significant light loss due to absorption of other colors, leading to inefficiencies in color display and image sensing applications.
Innovation Solution
The implementation of a color separating lens array that uses nanoposts arranged in specific patterns to separate and condense light of different wavelengths onto corresponding pixels, enhancing light utilization efficiency by minimizing absorption and maximizing transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a color filter is used to sense light color, then light color separation is achieved, but light utilization efficiency deteriorates due to absorption of non-corresponding colors
Solution Approach 1:
The patent extracts the light separation function from the color filter and implements it through a color separating lens array positioned before the pixel array. This allows incident light to be separated by wavelength through refraction in the lens array, directing different colors to appropriate pixels without absorption losses that occur in color filter-based systems.
Solution Approach 2:
The color separating lens array acts as an intermediary optical element between the incident light and the pixel array. It mediates the light separation process by using refractive index differences to spatially separate wavelengths, replacing the direct absorption-based separation of color filters with a refraction-based spatial separation mechanism.
2Measurement precision
If a color filter absorbs light of other colors to achieve color sensing, then color discrimination is improved, but light transmission efficiency deteriorates to about 33%
Solution Approach 1:
The patent replaces the absorption-based color filtering mechanism with a refraction-based optical routing mechanism. The color separating lens array uses the refractive index difference between materials to spatially separate and direct different wavelengths to appropriate pixels, substituting the mechanical absorption process with an optical refraction process that preserves more incident light.
3Ease of manufacture
If conventional color filter structures are used, then manufacturing simplicity is maintained, but light loss increases significantly
Solution Approach 1:
The patent segments the light separation function into a distinct color separating lens array component positioned above the pixel array. This segmentation allows the lens array to be manufactured and optimized separately for optical performance, using standard semiconductor fabrication processes for the nanopost structures, while maintaining compatibility with existing pixel array manufacturing.
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 solution significantly improves light utilization efficiency, allowing for the development of high-resolution, sensitive image sensors with reduced light loss, enabling the creation of ultra-high resolution and ultra-small image sensors for various electronic devices.
Implementation Method 1
a color separating lens array capable of focusing incident light separately according to wavelengths of the incident light
Implementation Method 2
a color separating lens array capable of focusing incident light separately according to wavelengths of the incident light
Data Source
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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.