Meta-Photonic Image Sensor Layout for Low-Loss Color Sensing
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Solution Overview
Problem
Image sensors using color filters suffer from low light utilization efficiency due to absorption of unwanted colors, leading to significant light loss, and existing optical structures for improving this efficiency are complex and costly to manufacture.
Innovation Solution
Incorporation of a meta-photonic structure with a crack stopper and nano-structures that separate light by wavelength, combined with a color filter layer and optical black region to enhance light utilization efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a color filter is used to sense color, then color detection is achieved, but light utilization efficiency deteriorates due to absorption of unwanted colors
Solution Approach 1:
The patent replaces the conventional color filter system with a meta-photonic structure that uses optical interference and diffraction effects instead of absorption. The meta-photonic structure separates light by wavelength through physical optics principles, allowing different wavelengths to be directed to different pixel regions without absorbing unwanted colors, thereby maintaining high light utilization efficiency while achieving color detection.
Solution Approach 2:
The patent changes the operating principle from absorption-based color filtering to interference-based wavelength separation. By adjusting the geometric parameters of the meta-photonic structure (such as pillar width, spacing, and height), the system can control light propagation paths for different wavelengths, enabling color detection while minimizing light loss.
2Loss of energy
If optical structures are applied to improve light utilization efficiency, then light loss is reduced, but manufacturing complexity and cost increase
Solution Approach 1:
The patent divides the sensor surface into multiple pixel regions with different meta-photonic structures, where each region is optimized for detecting specific wavelength ranges. This segmentation allows the use of relatively simple geometric patterns (such as cylindrical or rectangular pillars) that can be manufactured using standard photolithography techniques, reducing overall manufacturing complexity while maintaining high light utilization efficiency.
Solution Approach 2:
The patent uses periodic arrays of identical or similar meta-photonic unit cells across the sensor surface. These repeating patterns can be manufactured using template-based lithography or self-assembly methods, significantly reducing manufacturing complexity and cost compared to custom-designed optical structures.
3Reliability
If a crack stopper is added to protect against manufacturing cracks, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent integrates the crack stopper function with the existing meta-photonic structure by positioning the crack stopper at the periphery region surrounding the pixel regions. The crack stopper is formed as a continuous or segmented barrier that physically interrupts crack propagation paths without interfering with the optical function of the meta-photonic structures in the pixel regions, thereby providing protection while minimizing additional 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 meta-photonic structure and crack stopper design significantly reduces light loss by optimizing light separation and protection against manufacturing cracks, enhancing the overall efficiency of the image sensor.
Implementation Method 1
a meta-photonic structure arranged to face the sensor layer and including a plurality of nano-structures... separate incident light by each wavelength to condense the same
Implementation Method 2
a crack stopper arranged at a same layer as the meta-photonic structure so as to surround the plurality of nano-structures
Data Source
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AI summary
An image sensor comprises: an active pixel sensor region outputting a pixel signal for generating an image; and a periphery region surrounding the active pixel sensor region, where the active pixel sensor region and the periphery region each include a sensor layer that includes a plurality of pixels and extends through the active pixel sensor region and the periphery region, where the active pixel sensor region comprises (i) a meta-photonic structure facing the sensor layer, and (ii) a dielectric layer, the meta-photonic structure comprising a plurality of nano-structures arranged to have a meta pattern with the dielectric layer filled among the plurality of nano-structures, and where the periphery portion comprises (i) the dielectric layer integrally extending from the active pixel sensor region and (ii) a crack stopper having a groove shape formed within the dielectric layer.