Liquid Crystal Light Shutter for Clean Fluorescence Imaging
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Solution Overview
Problem
Existing medical imaging systems using global shutter imagers face contamination of fluorescence imaging data by ambient visible light and have slow mechanical shutters, limiting their ability to acquire both fluorescence and visible-light imaging data simultaneously.
Innovation Solution
Utilizing a liquid crystal light shutter to selectively block visible light from reaching the imager, allowing fluorescence light to pass in both states, and transitioning between states rapidly to enable simultaneous acquisition of clean fluorescence and visible-light imaging data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mechanical shutter is used to block visible light during fluorescence imaging, then fluorescence imaging data can be obtained, but the response time is slow (approximately 500 milliseconds) and the system cannot acquire both fluorescence and visible-light imaging data simultaneously
Solution Approach 1:
The patent replaces the mechanical shutter system with an electronic shuttering mechanism implemented through a global shutter imager. This electronic approach eliminates the mechanical moving parts that caused the 500ms response delay, enabling rapid switching between fluorescence and visible-light imaging modes without the inertia and friction constraints of mechanical components.
Solution Approach 2:
The patent changes the operational parameters of the imager by utilizing the global shutter's ability to capture all pixels simultaneously and hold the image data. This allows the system to rapidly alternate between blocking visible light (for fluorescence imaging) and allowing visible light (for white-light imaging) at the frame rate, achieving response times on the order of milliseconds rather than hundreds of milliseconds.
2Productivity
If ambient visible light is not blocked during fluorescence imaging, then the system can maintain continuous operation, but the fluorescence imaging data becomes contaminated by ambient visible light
Solution Approach 1:
The patent implements preliminary action by using the global shutter to pre-block visible light before fluorescence excitation occurs. The electronic shuttering mechanism ensures that the sensor is already in a state ready to capture only fluorescence signals, preventing ambient visible light contamination from the outset rather than attempting to correct it afterward.
Solution Approach 2:
The global shutter imager acts as an intermediary between the light sources and the sensor. It selectively controls which light reaches the sensor during different time intervals, mediating between the fluorescence excitation light, ambient visible light, and the sensor to ensure only the desired fluorescence signals are captured while maintaining continuous operation.
3Measurement precision
If ambient visible-light imaging data is acquired and subtracted from fluorescence imaging data, then clean fluorescence images can be obtained, but the number of frame periods increases and the output image update rate decreases
Solution Approach 1:
The patent extracts the visible light blocking function from the fluorescence imaging process itself. By using the global shutter to prevent visible light from reaching the sensor during fluorescence acquisition, the system eliminates the need to separately acquire and subtract ambient visible-light data, thereby extracting only the necessary fluorescence signals in a single frame period.
Solution Approach 2:
The patent maintains continuity of useful action by enabling the system to acquire both fluorescence and visible-light imaging data in continuous succession without interruption. The global shutter allows rapid alternation between modes at the frame rate, ensuring that the useful imaging action continues without the time losses associated with multiple acquisition and subtraction operations.
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
Enables simultaneous acquisition of uncontaminated fluorescence and visible-light imaging data, improving image update rate and usability for medical imaging applications.
Implementation Method 1
a liquid crystal light shutter configurable to be in an open state and a closed state
Implementation Method 2
transitioning the liquid crystal light shutter to the closed state to prevent the global shutter imager from receiving visible light
Implementation Method 3
a fluorescence excitation illumination source to illuminate the tissue of the subject
Data Source
AI summary
The present disclosure relates to techniques for imaging tissue of a subject. An exemplary method comprises transitioning the liquid crystal light shutter to the closed state to prevent the global shutter imager from receiving visible light; illuminating the tissue of the subject with the fluorescence excitation illumination source to accumulate charge at a plurality of pixels of the global shutter imager, while the liquid crystal light shutter is in the closed state; reading a set of accumulated charge at the plurality of pixels of the global shutter imager to produce a set of imaging data; and generating a fluorescence image frame based on the set of imaging data.