Double-Sided Spherical Lens for Image Sensor Crosstalk Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Highly integrated image sensors face increasing defects due to crosstalk issues, particularly optical and electrical crosstalk, as pixels become smaller, affecting their performance and efficiency.
Innovation Solution
An image sensor design incorporating a double-sided spherical lens with material layers of different refractive indices, integrated into a planarization lens layer, to improve light collection efficiency and reduce crosstalk by efficiently refracting incident light onto corresponding pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pixels are made smaller to increase integration, then productivity and integration are improved, but optical crosstalk increases and measurement precision deteriorates
Solution Approach 1:
The lens is divided into multiple material layers with different refractive indexes (first lens material layer with refractive index n1, second lens material layer with refractive index n2 where n1 < n2). This segmentation allows each layer to contribute differently to light refraction, improving light collection efficiency while reducing optical crosstalk between adjacent pixels, thus maintaining measurement precision even as pixel size decreases for higher integration density.
2Productivity
If pixels are made smaller to increase integration, then productivity is improved, but optical crosstalk increases
Solution Approach 1:
Different regions of the lens are assigned different material properties - the first lens material layer and second lens material layer have different refractive indexes (n1 < n2). This local quality variation enables precise control of light paths, directing light from each pixel to its corresponding photodiode while preventing light from adjacent pixels from interfering, thus reducing optical crosstalk in highly integrated sensors.
3Device complexity
If a single-material lens is used, then device complexity is reduced, but light collection efficiency is insufficient
Solution Approach 1:
The lens is constructed using composite materials - specifically, a first lens material layer and a second lens material layer with different refractive indexes (n1 < n2). This composite structure enables superior light refraction control and collection efficiency compared to single-material lenses, while the layered design remains compatible with existing semiconductor manufacturing processes, balancing complexity and performance.
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 enhances light collection efficiency and minimizes optical crosstalk, thereby improving the overall performance and reducing defects in image sensors by effectively guiding light to the intended pixel without crossing over to adjacent pixels.
Implementation Method 1
a lens layer arranged on the color filter layer and including a double-sided spherical lens, wherein the double-sided spherical lens includes at least two material layers having different refractive indexes
Data Source
AI summary
An image sensor including: a substrate which has a first surface and a second surface opposite to the first surface and pixels arranged in a two-dimensional array, wherein each of the pixels includes a photodiode; a multi-wiring layer arranged on the first surface of the substrate; a color filter layer arranged on the second surface of the substrate and including color filters that respectively correspond to the pixels; and a lens layer arranged on the color filter layer and including a double-sided spherical lens, wherein the double-sided spherical lens includes at least two material layers having different refractive indexes.