Vibrating Diffuser for Uniform Laser Illumination
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Solution Overview
Problem
Fluorescence imaging systems face challenges due to non-uniform excitation light sources, leading to artificial differences in fluorescence intensity, which can result in clinical misinterpretations and incorrect pixel intensity measurements, and require skin-safe and eye-safe illumination.
Innovation Solution
A fluorescence imaging system utilizing a vibrating diffuser and optical system to modify non-uniform laser diode illumination into a uniform 'top hat' beam, ensuring consistent excitation light intensity and safety standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a laser diode is used as the excitation light source, then the fluorescence signal intensity is improved, but the uniformity of illumination deteriorates
Solution Approach 1:
The patent employs a vibrating diffuser that dynamically oscillates at a specific frequency to scatter the laser diode beam. This dynamic vibration transforms the static non-uniform Gaussian beam into a uniformly distributed illumination pattern across the field of view, resolving the contradiction between high intensity and uniformity.
Solution Approach 2:
The diffuser is mechanically vibrated at a resonant frequency to create time-varying scattering patterns. This mechanical vibration distributes the laser energy uniformly across the illumination area, converting the concentrated Gaussian profile into a homogeneous 'top hat' beam profile while maintaining high overall intensity.
2Device complexity
If a non-uniform laser beam is used for illumination, then the system complexity is reduced, but the measurement precision deteriorates
Solution Approach 1:
The vibrating diffuser introduces dynamic scattering that uniformizes the beam profile without requiring complex optical elements. This simple mechanical vibration approach achieves uniform illumination, enabling accurate pixel intensity measurements while keeping the overall system relatively simple.
3Power
If a laser diode with high power is used, then the fluorescence excitation capability is improved, but the safety risk increases
Solution Approach 1:
The vibrating diffuser scatters the high-power laser beam through dynamic vibration, distributing the energy across a wider area and reducing the power density at any single point. This reduces the risk of skin and eye damage while maintaining sufficient total power for fluorescence excitation.
Solution Approach 2:
The diffuser acts as an intermediary element between the high-power laser diode and the tissue. It transforms the concentrated high-power beam into a distributed illumination pattern, mediating the safety risk while preserving the excitation capability.
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 provides clinically accurate and reliable fluorescence imaging by ensuring uniform illumination, reducing misinterpretations and enhancing safety by diffusing the laser beam, making it suitable for skin and eye safety standards.
Implementation Method 1
A diffuser that vibrates along the plane its plane is known in the art... Speckle noise from a laser-based system is reduced by dynamically diffusing the laser beam.
Implementation Method 2
The optical system is configured to modify the non uniform fluence illumination beam into a uniform fluence illumination beam
Implementation Method 3
The diffuser is bonded to a thin elastic membrane, which includes four independent electro-active polymer electrodes that induce a circular oscillation of the diffuser in X and Y directions.
Implementation Method 4
The excitation light filter is positioned between the object and the camera. The excitation light filter is configured for filtering out the excitation illumination beam, such that the excitation illumination beam does not reach the camera.
Data Source
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AI summary
A fluorescence imaging system including a light source, an optical system, camera and an excitation light filter, the optical system produces a non-uniform fluence excitation illumination beam for illuminating an object and promoting fluorescence emissions, the optical system is positioned between the light source and the object, the optical system modifies the non-uniform fluence illumination beam into a uniform fluence illumination beam and changes the divergence of the uniform fluence illumination beam, the camera has an array of pixels, the camera detects the fluorescence emissions and performs pixel intensity measurements for each of the pixels, the excitation light filter is positioned between the object and the camera and filters out the excitation illumination beam, such that the excitation illumination beam does not reach the camera.