Nano-Photonic Image Sensor With Patterned Anti-Reflection Layer
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Solution Overview
Problem
Image sensors suffer from low light utilization efficiency due to the absorption of unwanted light colors by color filters and reflection at interfacial layers, leading to significant light loss.
Innovation Solution
An image sensor with a patterned anti-reflection layer and a nano-photonic lens array that includes periodically arranged nano-patterns and meta-regions to reduce reflection loss and enhance light focusing, where the distance between nano-structures and nano-patterns satisfies a specific condition to optimize light separation and focusing.
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 unwanted colors
Solution Approach 1:
The patent removes the color filter layer from the image sensor structure and replaces it with a nano-photonic lens array that performs both color separation and light focusing functions. This extraction of the color filter eliminates the 2/3 light absorption problem while maintaining color separation capability through wavelength-dependent refraction in the nano-structures.
Solution Approach 2:
The nano-photonic lens array performs multiple functions simultaneously: it acts as both a color separation element (replacing the color filter) and a light focusing element (replacing the microlens). This multi-functionality integrates the roles of color filtering and light concentration into a single component, improving overall light utilization.
2Measurement precision
If multiple layers with different refractive indices are used in the image sensor, then light color separation is enabled, but reflection loss increases at interfacial layers
Solution Approach 1:
The patent introduces an anti-reflection layer with a graded refractive index structure (using nano-patterns) as an intermediary between the nano-photonic lens array and the incident light. This intermediary layer gradually transitions the refractive index from air to the substrate material, minimizing reflection at each interface while maintaining the optical path for color separation.
Solution Approach 2:
The anti-reflection layer utilizes controlled changes in refractive index through its nano-patterned structure. By varying the density and arrangement of nano-patterns, the effective refractive index is gradually changed from that of air at the top surface to that of the substrate at the bottom, reducing reflection losses at each transition point.
3Loss of energy
If a nano-photonic lens array is introduced to improve light focusing, then light utilization efficiency is improved, but device complexity increases
Solution Approach 1:
The patent merges the color separation function and light focusing function into a single integrated nano-photonic lens array structure. Instead of having separate color filters and microlenses, the nano-structures perform both functions simultaneously, reducing the number of discrete components and simplifying the overall device architecture.
Solution Approach 2:
The patent transitions from conventional two-dimensional planar color filters to three-dimensional nano-photonic structures with controlled refractive indices in multiple dimensions. This dimensional transition enables color separation through spatial arrangement and refractive index gradients rather than requiring separate color filter layers, reducing structural 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
The solution significantly improves light utilization efficiency by minimizing reflection and enhancing light focusing, thereby increasing the overall performance of the image sensor.
Implementation Method 1
an anti-reflection layer on a light incident surface of the nano-photonic lens array, the anti-reflection layer being configured to reduce a reflection loss
Implementation Method 2
the plurality of meta-regions include a plurality of nano-structures configured to color-separate light that is incident on the nano-photonic lens array
Implementation Method 3
the plurality of meta-regions include a plurality of nano-structures configured to color-separate light that is incident on the nano-photonic lens array and focus the light onto each of the plurality of pixels
Data Source
AI summary
Provided is an image sensor including a sensor substrate including a plurality of pixels configured to sense light, the plurality of pixels being are two-dimensionally provided, a nano-photonic lens array including a plurality of meta-regions respectively corresponding to the plurality of pixels, and an anti-reflection layer on a light incident surface of the nano-photonic lens array, the anti-reflection layer being configured to reduce a reflection loss and including a plurality of nano-patterns that are periodically and two-dimensionally provided, wherein the plurality of meta-regions include a plurality of nano-structures configured to color-separate light that is incident on the nano-photonic lens array and focus the light onto each of the plurality of pixels.