Dual Meta-Lens Image Sensor for Thin Pixels and High Sensitivity
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Solution Overview
Problem
Existing image sensing devices face challenges in reducing pixel size without increasing epitaxial thickness, which affects spatial resolution and sensitivity, particularly in RGB and infrared sensing devices.
Innovation Solution
The implementation of a cavity resonance structure with dual meta-lens layers, comprising a first meta-lens layer to focus incident light and a second meta-lens layer to scatter or reflect light, reduces epitaxial thickness while maintaining sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If epitaxial thickness is increased to maintain sensitivity, then sensitivity is improved, but pixel size cannot be reduced and manufacturing cost increases
Solution Approach 1:
The patent introduces meta-lens layers that manipulate light in three-dimensional space, creating cavity resonance structures that trap and guide light vertically through the photodetector. This dimensional approach to light management allows reduced epitaxial thickness while maintaining sensitivity, as the resonance cavity confines light within a smaller vertical space.
Solution Approach 2:
The patent changes the optical parameters by introducing meta-lens structures with specific refractive indices and geometries. These meta-lenses create resonance conditions that enhance light-matter interaction, allowing the system to achieve high sensitivity with reduced material thickness by optimizing optical field distribution rather than relying solely on increased thickness.
2Measurement precision
If epitaxial thickness is reduced to enable smaller pixel size, then spatial resolution is improved, but sensitivity deteriorates
Solution Approach 1:
The meta-lens layers create vertical cavity resonance that confines light in the thickness direction, effectively using the third dimension to compensate for reduced lateral light collection. The resonance cavity structure guides light vertically through the thinned photodetector, maintaining sensitivity despite reduced epitaxial thickness that enables smaller pixel pitch and higher spatial resolution.
Solution Approach 2:
The meta-lens layers act as intermediary structures that mediate between the reduced-thickness photodetector and incident light. These layers focus and trap light within the cavity region, ensuring that even with minimal epitaxial thickness, sufficient light energy is delivered to the photodetector active region to maintain sensitivity while enabling higher spatial resolution.
3Measurement precision
If dual meta-lens layers are added to reduce epitaxial thickness, then spatial resolution is improved, but device complexity increases
Solution Approach 1:
The meta-lens layers perform multiple functions simultaneously: they focus incident light onto the photodetector, create cavity resonance to trap and guide light vertically, and enable the system to operate with reduced epitaxial thickness. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in overall device complexity while achieving improved spatial resolution.
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
This approach enhances spatial resolution and sensitivity by minimizing epitaxial thickness, addressing process limitations and cost increases associated with larger epitaxial thickness in RGB and infrared sensing devices.
Implementation Method 1
a first meta-lens layer disposed over the upper layer and configured to focus incident light
Implementation Method 2
a second meta-lens layer disposed below the lower layer and configured to scatter or reflect the incident light toward the photodetectors
Data Source
AI summary
Image sensing devices are disclosed. In an embodiment, an image sensing device may include: a lower layer including a substrate and a plurality of photodetectors such as photodiodes; an upper layer disposed over the lower layer; a first meta-lens layer disposed over the upper layer and configured to focus incident light; and a second meta-lens layer disposed below the lower layer and configured to scatter or reflect the incident light toward the photodetector.