Quantum Dot Imaging Sensor Array for Uniform VIS-NIR Responsivity
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Solution Overview
Problem
Conventional imaging sensors, particularly those based on InGaAs, suffer from low responsivity and non-uniform spectral response across the visible and near-infrared spectrum, limiting their ability to detect weak optical signals effectively.
Innovation Solution
The use of quantum dots with varying diameters arranged in an array structure, each optimized for specific wavelengths, enhances quantum efficiency and responsivity by matching the absorption maximum of each detector element to the incident light wavelength, thereby improving the overall sensitivity of the imaging sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If InGaAs-based detector elements are used, then sensitivity to NIR light is improved, but responsivity remains less than 1 A/W over considerable parts of the VIS and NIR spectrum
Solution Approach 1:
The patent applies local quality by using quantum dots with different sizes at different positions along the array axis. Each quantum dot size is optimized for a specific wavelength range, creating local optimization rather than uniform material properties. This allows each detector element to have maximum responsivity at its designated wavelength position.
Solution Approach 2:
The patent changes the size parameter of quantum dots along the array axis to optimize absorption at different wavelengths. By systematically varying the quantum dot diameter, the absorption maximum shifts across the spectrum, achieving high responsivity (1.0 or more) over extended wavelength ranges while maintaining NIR sensitivity.
2Measurement precision
If quantum dots with varying sizes are used along the array axis, then responsivity is improved to 1.0 or more over 85-90% of the target range, but device complexity increases
Solution Approach 1:
The patent segments the imaging sensor into multiple detector elements along an array axis, with each element containing quantum dots of a specific size optimized for a particular wavelength. This segmentation allows independent optimization of each element's quantum dots while maintaining a relatively simple overall array structure that can be manufactured using standard techniques.
3Ease of manufacture
If alternatives to InGaAs-based detector elements are investigated (Bulk PbS, PbS quantum dots, graphene combinations, NIR polymers), then cost and material availability may be improved, but performance does not reach the same level as InGaAs
Solution Approach 1:
The patent uses composite material structures by combining quantum dots with varying sizes within a single imaging sensor array. This composite approach allows the system to achieve performance comparable to or exceeding InGaAs across the entire VIS-NIR spectrum by leveraging the complementary strengths of different quantum dot sizes, while using materials that are more readily available and cost-effective.
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 results in an imaging sensor with high and uniform responsivity across an extended spectrum, achieving a responsivity of 1 or more over 85% of the target range, significantly enhancing the sensor's sensitivity and detection capabilities.
Implementation Method 1
detector elements comprising quantum dots, wherein the average diameter of the quantum dots of the detector elements increase along an array axis of the array structure such that each of the detector elements along the array axis has an absorption maximum at a different pre-determined wavelength
Implementation Method 2
each of the detector elements along the array axis has an absorption maximum at a different pre-determined wavelength
Data Source
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AI summary
An imaging sensor comprises a plurality of light-sensitive detector elements being arranged in an array structure, the detector elements comprising quantum dots, wherein the average diameter of the quantum dots of the detector elements increase along an array axis of the array structure such that each of the detector elements along the array axis has an absorption maximum at a different pre-determined wavelength. Further, a sensor system and a method for manufacturing an imaging sensor is presented.