Quantum Dot Image Sensor Stacking for Longer TOF Depth Range
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Solution Overview
Problem
Current depth imaging systems, particularly those using time-of-flight technology, face challenges in miniaturization and have limited detectable distances, making them unsuitable for applications like smartphones and requiring improved accuracy and detection range.
Innovation Solution
The development of an image sensor with a light absorption layer composed of quantum dot semiconductor materials, including multiple P-region layers and a N-region layer with cylindrical structures, enhances the detection distance and accuracy of depth imaging systems by integrating the light emitter and image sensor into a single chip module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional TOF depth imaging systems are miniaturized for smartphones, then device portability is improved, but detection distance is reduced
Solution Approach 1:
The patent transitions from conventional planar photodetector structures to a three-dimensional stacked architecture with multiple P-region layers (first P-region layer, second P-region layer) positioned at different vertical levels above the N-region layer. This vertical stacking enables enhanced light absorption efficiency within a compact footprint, improving detection distance without increasing device planar dimensions.
Solution Approach 2:
The patent employs a composite semiconductor structure combining N-type semiconductor material in the N-region layer with P-type semiconductor material in the P-region layers, forming a P-N junction configuration. This composite material approach optimizes both light absorption efficiency and charge carrier separation, enabling extended detection range while maintaining miniaturized device form factor.
2Measurement precision
If quantum dot semiconductor materials are used in the light absorption layer, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent divides the light absorption function across multiple segmented P-region layers (first P-region layer, second P-region layer) stacked vertically above the N-region layer. Each layer contributes to light absorption at different depths, enhancing overall detection accuracy through cumulative signal collection while maintaining a modular structure that manages complexity through systematic repetition of functional units.
Solution Approach 2:
The P-region layers serve multiple functions simultaneously: they act as light absorption regions, charge generation zones, and electrical connection interfaces to the N-region layer. This multi-functionality reduces the need for separate dedicated components, thereby improving detection accuracy without proportionally increasing device complexity.
3Reliability
If multiple P-region layers are stacked above the N-region layer, then light absorption efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The patent implements a periodic stacking pattern of P-region layers separated by intermediate regions, creating a repeating structural motif that facilitates standardized manufacturing processes. This periodic architecture allows for modular fabrication approaches where identical layer sequences can be reproduced systematically, improving light absorption efficiency while managing manufacturing complexity through pattern repetition.
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 configuration significantly increases the detection distance and improves the accuracy of time-of-flight depth imaging systems, enabling their integration into smaller devices like smartphones while maintaining high signal-to-noise ratios and reducing dark current rates.
Implementation Method 1
The light absorption layer is composed of a multi-layer structure including a P-region layer formed using quantum dot semiconductor materials
Data Source
AI summary
The present disclosure provides an image sensor, which may include a driving layer, a negative electrode layer formed in the driving layer, a N-region layer formed above the negative electrode layer. The N-region layer includes multiple cylindrical structures formed of semiconductor materials. The image sensor may also include a light absorption layer formed above the N-region layer. The light absorption layer is composed of a multi-layer structure including a P-region layer formed using quantum dot semiconductor materials. The image sensor may further include a positive electrode layer formed above the light absorption layer and configured to receive incoming light signals.