Flexible SPAD Detector Array for Non-Invasive Neural Imaging
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Solution Overview
Problem
Current neural imaging technologies face challenges in achieving high spatiotemporal resolution non-invasively, with existing methods either providing poor spatial or temporal resolution, or requiring invasive procedures due to tissue scattering and absorption.
Innovation Solution
A diffuse optical tomography (DOT) system using near-infrared (NIR) photons with a flexible substrate and single photon avalanche diode (SPAD) detectors, integrated on a CMOS chip, capable of generating and detecting NIR photons to achieve high spatiotemporal resolution by measuring time-of-flight and absorption, allowing for non-invasive brain imaging with sub-mm spatial and millisecond temporal resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If non-invasive optical imaging methods are used, then invasiveness is reduced, but spatial and temporal resolution deteriorate
Solution Approach 1:
The patent uses time-correlated single photon counting (TCSPC) as an intermediary detection method that bridges the gap between non-invasive optical imaging and high-resolution measurement. By detecting the precise arrival times of individual photons and using time-gated detection, the system achieves millisecond temporal resolution and sub-mm spatial resolution without requiring invasive procedures, thus resolving the contradiction between non-invasiveness and measurement precision.
Solution Approach 2:
The system changes the detection parameter from conventional optical detection to time-correlated single photon counting. By measuring the time of flight of photons and using time-gated detection windows, the system transforms optical signals into temporally resolved data, enabling millisecond temporal resolution while maintaining non-invasive optical imaging, thereby resolving the resolution-invasiveness tradeoff.
2Measurement precision
If time-gated detection is used, then temporal resolution is improved, but device complexity increases
Solution Approach 1:
The time-gated detection system uses the photons' own flight time information to automatically sort and gate detection events. The TCSPC method inherently provides time-stamping of each photon detection, eliminating the need for external complex timing control systems. The system self-regulates the detection window based on the expected photon arrival time, reducing overall device complexity while maintaining high temporal resolution.
3Measurement precision
If single photon avalanche diode detectors are used, then detection sensitivity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent uses an array of identical SPAD detectors where each detector operates as an independent unit with standardized characteristics. By using multiple copies of the same detector type arranged in an array, the system achieves high detection sensitivity through parallel measurement while distributing manufacturing tolerances across multiple units. The time-correlated analysis method further compensates for minor variations between detectors, reducing the stringency of individual manufacturing precision requirements.
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 system achieves high spatiotemporal resolution of sub-mm and milliseconds, enabling effective non-invasive neural activity measurement and improving signal-to-noise ratio, while reducing the need for invasive procedures by utilizing time-gated detection and genetically encoded indicators.
Implementation Method 1
an optical source(s) that is configured to generate a plurality of near infrared ('NIR') photons
Implementation Method 2
The scattering and absorption produced by the scalp, skull, and brain tissue
Implementation Method 3
single photon avalanche diode ('SPAD') detectors... configured to detect a plurality of backscattered NIR photons
Implementation Method 4
The detectors can be configured to measure an arrival time of the backscattered NIR photons
Implementation Method 5
each of the detectors can be configured to detect... based on the NIR photons... determining an absorption of the NIR photons by the anatomical structure
Data Source
AI summary
An exemplary diffuse optical tomography (DOT) device, can be provided, which can include, for example, a flexible substrate, an optical source(s) configured to generate a plurality of near infrared (NIR) photons disposed on the flexible substrate, and a plurality of detectors disposed on the flexible substrate, wherein each of the detectors can be configured to detect a plurality of backscattered NIR photons from an anatomical structure(s) that can be based on the NIR photons. The flexible substrate can be configured to be applied to an anatomical structure. The detectors can be an array of single photon avalanche diode (SPAD) detectors. The detectors can be configured to measure an arrival time of the backscattered NIR photons. The array can be disposed on a CMOS integrated circuit chip, which can be disposed on the flexible substrate.