Nanopost Color-Separating Lens Array for Filterless Image Sensors
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Solution Overview
Problem
Conventional image sensors utilize color filters that absorb light other than the intended color, resulting in low light utilization efficiency, with most light loss occurring in the color filter, prompting the need for a method to separate colors by wavelength without using filters.
Innovation Solution
An image sensor incorporating a color separating lens array that changes the phase of incident light by wavelength and condenses it onto specific pixels, using nanoposts arranged in distinct regions to achieve wavelength-specific light separation and improved autofocus performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a color filter is used to sense the color of incident light, then color separation is achieved, but light utilization efficiency is degraded due to absorption of light other than the corresponding color
Solution Approach 1:
The invention extracts and removes the color filter from the optical path. Instead of using a color filter to separate wavelengths, the patent employs a microlens array that directly guides different wavelengths of light to corresponding pixels based on their focal lengths, eliminating the light-absorbing filter component entirely
Solution Approach 2:
The invention replaces the optical filtering mechanism (color filter) with a geometric/optical focusing mechanism (microlens array). The microlens array uses differences in focal length for different wavelengths to achieve spectral separation without absorption, substituting a mechanical/optical focusing system for a filtration system
2Measurement precision
If a color filter is used to separate colors, then color information is obtained, but most light loss occurs in the color filter reducing overall efficiency
Solution Approach 1:
The color filter is extracted and removed from the system. The patent achieves color information detection without a color filter by using a microlens array to spatially separate wavelengths based on their focal properties, allowing all incident light to be utilized rather than absorbed by a filter
Solution Approach 2:
The invention changes the optical parameters of the system by using microlenses with different focal lengths for different wavelengths. This parameter-based separation (focal length differentiation) replaces the absorption-based separation of color filters, enabling full light utilization while maintaining color detection capability
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
Enhances light efficiency and autofocus performance by effectively separating colors without absorbing light, reducing light loss and improving image sensor performance.
Implementation Method 1
a color separating lens array changing phase of the light of the first wavelength, the second wavelength, and the third wavelength and condensing the phase-changed light of the first wavelength, the second wavelength, and the third wavelength onto the first pixel, the second pixel, and the third pixel respectively
Implementation Method 2
a color separating lens array changing phase of the light of the first wavelength, the second wavelength, and the third wavelength and condensing the phase-changed light
Data Source
AI summary
An image sensor includes a sensor substrate includes first, second, and third pixels respectively sensing first, second and third wavelengths of light, A color separating lens array changes phase of light of the first, second, and third wavelengths, and condenses the phase-changed light onto the first, second and third pixels, respectively. The color separating lens array includes first to third pixel corresponding regions respectively facing the first to third pixels. The first pixel corresponding region includes a plurality of first nanoposts, the second pixel corresponding region includes a plurality of second nanoposts, and the third pixel corresponding region includes a plurality of third nanoposts, a second center nanopost having a greatest cross-sectional width among the second nanoposts overlaps a center of the second pixel, and a third center nanopost having a greatest cross-sectional width among the third nanoposts does not overlap a center of the third pixel.