Back-Illuminated Photodetector Arrays With Photon-Trapping Nanostructures
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Solution Overview
Problem
Existing photodetector arrays for LIDAR and 3D imaging technologies face challenges in manufacturing accuracy and cost due to the need for complex components like micro-lens arrays.
Innovation Solution
The integration of photon-trapping nanostructures (PTN) in the detection layer and fill regions of photodetector arrays, which cause optical energy to disperse perpendicular to the incident direction, improving absorption efficiency without the need for costly micro-lens arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If micro-lens arrays are used to improve optical energy absorption, then absorption efficiency is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent extracts the optical energy concentration function from the complex micro-lens array structure and relocates it to the fill regions between detector elements. By placing simplified optical structures only where needed (in fill regions rather than across the entire surface), the patent reduces manufacturing complexity while maintaining the optical energy concentration function.
Solution Approach 2:
The patent replaces expensive, complex micro-lens arrays with simpler, more affordable optical structures formed directly in the fill regions. These simplified structures achieve the necessary optical function at lower manufacturing cost and with easier fabrication processes.
2Loss of energy
If micro-lens arrays are used to improve optical energy absorption, then absorption efficiency is improved, but manufacturing cost increases
Solution Approach 1:
The patent extracts the optical energy concentration function from the expensive micro-lens array and implements it through simpler structures in the fill regions. This extraction allows the system to achieve the same optical function at lower manufacturing cost.
Solution Approach 2:
The patent uses cost-effective optical structures formed directly in the fill regions instead of expensive micro-lens arrays. These simplified structures provide the necessary optical energy concentration at a fraction of the manufacturing cost.
3Ease of manufacture
If fill regions are added between detector structures, then manufacturing ease is improved, but optical energy absorption is reduced
Solution Approach 1:
The patent applies local quality by placing optical energy concentration structures specifically in the fill regions where they are most needed. The fill regions are designed with different optical properties than the detector structures, creating localized optical functionality that concentrates light onto detector elements without compromising the overall manufacturing simplicity.
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 solution enhances the absorption efficiency of photodetector arrays, reducing the complexity and cost of manufacturing while maintaining accurate performance in LIDAR and 3D imaging applications.
Implementation Method 1
The PTN cause optical energy incident on the back side to disperse in a direction perpendicular to the incident direction
Implementation Method 2
improve an absorption efficiency of the back-illuminated PDA
Data Source
AI summary
A back-illuminated photo detector array (PDA) includes a front side and a back side. The back side receives optical energy incident on the back side at an incident direction. The front side includes a detection layer that includes detection structures and a plurality of photon-trapping nanostructures (PTN). The PTN cause optical energy incident on the back side to disperse in a direction perpendicular to the incident direction, and thereby improve an absorption efficiency of the back-illuminated PDA.