Air Grid Image Sensor Pixel Isolation
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Solution Overview
Problem
Image sensors face optical interference between pixels, leading to noise in pixel signals due to unwanted light crosstalk, which affects image quality and resolution.
Innovation Solution
An image sensor design incorporating an air grid structure with low-index material or air to provide optical isolation between pixels, featuring a grid structure with holes at crossing points and a refractive index configuration that minimizes light transmission between adjacent pixels, including a metal layer and capping films to absorb or reflect stray light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If air grid structure is used to provide optical isolation between pixels, then optical crosstalk is reduced, but structural stability deteriorates when air pressure increases
Solution Approach 1:
The air grid structure is divided into multiple independent air holes instead of a continuous air layer. Each air hole is isolated and surrounded by support structures, segmenting the air pressure distribution. This segmentation prevents uniform pressure buildup across the entire grid while maintaining optical isolation between pixels through the individual air holes.
Solution Approach 2:
The patent introduces support structures (such as posts or walls) at specific locations within the air grid structure. These localized support elements provide mechanical reinforcement exactly where needed to maintain structural stability under air pressure, while the rest of the air grid maintains its low refractive index property for optical isolation. This creates local quality differences - stable supported regions and optically active air regions.
2Ease of manufacture
If continuous air layer is used for optical isolation, then manufacturing is simplified, but structural stability under air pressure deteriorates
Solution Approach 1:
The continuous air layer is segmented into discrete air holes arranged in a grid pattern. This segmentation is achieved through standard semiconductor fabrication processes such as photolithography and etching, which can create periodic hole patterns. The segmented structure maintains ease of manufacture while the holes provide structural support points that prevent collapse under air pressure.
Solution Approach 2:
The air grid structure combines air (low refractive index material) with solid support structures (higher refractive index material) to create a composite structure. The air portions provide optical isolation, while the solid support portions provide mechanical strength. This composite approach allows the structure to withstand air pressure while maintaining its optical isolation function.
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 air grid structure effectively reduces optical crosstalk, enhancing image quality by minimizing noise and improving pixel isolation, while maintaining structural stability through pressure distribution across the grid.
Implementation Method 1
the grid structure including a low-index material or an air to provide optical isolation between two adjacent imaging pixels
Implementation Method 2
a refractive index configuration that minimizes light transmission between adjacent pixels
Implementation Method 3
including a metal layer and capping films to absorb or reflect stray light
Implementation Method 4
including a metal layer and capping films to absorb or reflect stray light
Data Source
AI summary
Designs of image sensors by including at least one grid structure extending in rows and columns of a pixel array including a plurality of imaging pixels arranged in rows and columns and structured to separate the imaging pixels from one another, the grid structure including a low-index material or an air to provide optical isolation between two adjacent imaging pixels, and a plurality of holes respectively formed at crossing points of the grid structures.