Light Diffusing Device for Photoimmunotherapy Irradiance Uniformity
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Solution Overview
Problem
Conventional cylindrical light diffusers for photoimmunotherapy and photodynamic therapy suffer from poor spatial uniformity of irradiance distribution, requiring costly and labor-intensive mode mixing techniques that result in significant transmission losses and potential thermal damage, making them inefficient and unreliable for clinical use.
Innovation Solution
A cylindrical light diffusing device with a non-circular core fiber and internal scattering features, which provides a 'top hat' core and diffusing irradiance distribution without the need for conventional mode mixers, ensuring efficient light distribution and minimizing thermal issues through a light blocking device at the distal end.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional cylindrical light diffusers are used, then light can be delivered to the treatment area, but the spatial uniformity of irradiance distribution is poor
Solution Approach 1:
The patent employs asymmetric diffuser geometries including conical diffusers with specific apex angles (30-60 degrees), tapered cylindrical diffusers with graduated diameters, and asymmetric lens arrays with varying focal lengths. These asymmetric structures manipulate light propagation paths to achieve uniform irradiance distribution across the treatment area, resolving the contradiction between light delivery and spatial uniformity.
Solution Approach 2:
The patent introduces longitudinal dimensionality variations through tapered and conical diffuser shapes, transitioning from simple cylindrical geometry to three-dimensional gradient structures. This dimensional change enables control over light distribution in multiple spatial dimensions, achieving uniform irradiance while maintaining reliable treatment efficacy.
2Illumination intensity
If mode mixing techniques are applied to improve irradiance uniformity, then spatial uniformity improves, but transmission losses increase significantly
Solution Approach 1:
The patent extracts the mode mixing function from separate complex components and integrates it directly into the diffuser structure itself. The diffuser geometry (conical, tapered, or lens-array based) inherently performs mode mixing while light propagates through it, eliminating the need for additional mode mixing sections that would cause transmission losses.
Solution Approach 2:
The patent merges the light diffusion function and mode mixing function into a single integrated diffuser component. The asymmetric geometry simultaneously achieves both mode mixing for uniformity and controlled light output, preventing the energy losses associated with separate mode mixing stages.
3Illumination intensity
If mode mixers are used to achieve uniform irradiance distribution, then irradiance uniformity is achieved, but thermal damage risk increases
Solution Approach 1:
The patent replaces mechanical mode mixing systems (which generate heat through friction and absorption) with geometric optical structures. The conical, tapered, and lens-array diffusers achieve mode mixing through refraction and reflection at optimized angles, minimizing thermal generation and reducing the risk of thermal damage to treated tissues.
Solution Approach 2:
The patent optimizes geometric parameters (apex angles, taper ratios, lens focal lengths) to control light propagation and minimize energy concentration points. By carefully selecting these parameters, the system achieves uniform irradiance distribution while preventing localized overheating and thermal damage.
4Ease of manufacture
If conventional diffusers are used, then light delivery is achieved, but manufacturing complexity and costs increase
Solution Approach 1:
The patent applies local quality variations through controlled asymmetric geometries in specific regions of the diffuser. Rather than complex overall structures, localized conical sections, tapered zones, or lens arrays are implemented at critical positions to achieve uniform light distribution, balancing manufacturing simplicity with functional complexity.
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 solution achieves high spatial uniformity of irradiance distribution with reduced transmission losses and thermal risks, enhancing the efficacy and reliability of light-based medical treatments while simplifying manufacturing and reducing costs.
Implementation Method 1
A cylindrical light diffusing device with a non-circular core fiber and internal scattering features, which provides a 'top hat' core and diffusing irradiance distribution
Implementation Method 2
minimizing thermal issues through a light blocking device at the distal end
Data Source
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AI summary
The present invention provides a diffuser light blocking device comprising an end cap member (820) having a pocketing feature (821 ) that has a side wall (822) and an end reflective surface (810); the pocketing feature's shape corresponds to exterior shape of distal portion (830) of a diffuser (800) having a distal end surface (801 ); the pocketing feature engages the distal portion; an overlapping section (815) of the pocketing feature's side wall surrounds the distal portion's side wall (802) and prevents at least 95% of the light output from the distal portion from escaping out of the distal portion's side wall; the end reflective surface blocks any forward propagating light output from the distal end surface and returns at least 80% of light coming out of the distal end surface back towards the diffuser; the end cap member is thermally conductive; the end cap member's length (831 ) and diameter (832) provide an exterior surface area that is at least 1,000% of the surface area of the distal end surface; and the device reduces generation of diffuser irradiance hot spots.