Combined SWIR and Visible Light Sensor Using Quantum Dot Detection
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Solution Overview
Problem
Existing optical sensors struggle to efficiently integrate both short-wavelength infrared (SWIR) and visible light detection capabilities in a single semiconductor die, limiting their imaging performance in applications such as advanced driver assistance systems and autonomous driving.
Innovation Solution
A semiconductor optical sensor is designed with an array of pixels that includes both SWIR and visible light detectors, utilizing colloidal quantum dots for SWIR detection and a color filter array with microlenses for enhanced sensitivity, integrated with an ASIC die through hybrid bonding for efficient signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single semiconductor die integrates both SWIR and visible light detection capabilities, then imaging performance and sensitivity are improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The semiconductor die is divided into distinct pixel regions: SWIR detector pixels and visible light detector pixels are spatially segmented within the same die. Each pixel type has dedicated photodetector structures optimized for its specific wavelength range, allowing both functions to coexist without mutual interference while maintaining high imaging performance for both modalities.
Solution Approach 2:
The semiconductor die is designed as a multi-functional device that simultaneously performs both SWIR and visible light detection. The shared semiconductor substrate, readout circuitry, and packaging structure support dual detection modes, reducing overall system complexity compared to using separate dedicated sensors while achieving improved imaging performance through combined functionality.
2Measurement precision
If colloidal quantum dots are used for SWIR detection, then SWIR sensitivity is improved, but manufacturing precision and fabrication difficulty increase
Solution Approach 1:
The photodetector structures are designed with adjustable parameters including quantum dot size, composition, and distribution density to optimize SWIR sensitivity. By controlling these parameters during fabrication, the device achieves high SWIR detection capability while managing manufacturing complexity through standardized processing techniques.
Solution Approach 2:
Colloidal quantum dots are integrated into the semiconductor structure as a composite material layer. These quantum dot layers are combined with the underlying semiconductor substrate and associated photodetector structures, creating a composite device that achieves enhanced SWIR sensitivity while utilizing established semiconductor fabrication processes for the supporting infrastructure.
3Measurement precision
If a color filter array with microlenses is integrated, then visible light sensitivity is improved, but device complexity increases
Solution Approach 1:
The color filter array and microlens array are merged into a single integrated optical layer above the visible light detector pixels. This combined structure performs both color filtering and light focusing functions simultaneously, improving visible light sensitivity while reducing the number of separate components and assembly steps compared to having distinct filter and lens arrays.
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 integrated sensor achieves improved imaging performance by combining SWIR and visible light detection, enhancing resolution and sensitivity, suitable for automotive applications like ADAS and autonomous driving.
Implementation Method 1
at least one pixel configured to detect short wavelength infrared radiation (SWIR)
Implementation Method 2
a microlens array to help funnel incoming light into each pixel (thereby increasing the sensitivity of the image sensor)
Implementation Method 3
include a color filter array (CFA)
Data Source
AI summary
A sensor includes an array of optically active pixels disposed on a semiconductor die. The array of optically active pixels includes at least one pixel (P1) configured to detect short wavelength infrared radiation (SWIR), and at least one pixel (P2) configured to detect visible light incident on the sensor.