Optical Fiber Light Diffusion Device for Uniform Emission
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Solution Overview
Problem
Conventional light diffusion devices face challenges in uniformly emitting laser light due to refractive index differences between the core and air, leading to non-uniform emission intensity and increased thermal resistance, which can cause heat-related issues during photoimmunotherapy.
Innovation Solution
A light diffusion device with an optical fiber where the cladding thickness in the light emitting part is reduced to less than in the light transmitting part, forming an uneven surface with a height difference no greater than the wavelength of the light, allowing for uniform light emission and reduced thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If cladding is deeply etched or roughened until the core is exposed to increase light emission area, then the area of interface between core and air increases, but thermal resistance increases and heat generation increases
Solution Approach 1:
The patent applies local quality by creating different surface characteristics in different regions of the light emitting part. Specifically, it forms protrusions and recesses with controlled dimensions (protrusion height 0.1-10μm, recess depth 0.1-5μm) on the cladding outer peripheral surface. This local structural modification enables uniform light emission while controlling the interface area to minimize thermal resistance and heat generation.
Solution Approach 2:
The patent changes the physical parameters of the cladding surface by controlling the height and depth dimensions of protrusions and recesses to be within specific ranges (0.1-10μm for protrusions, 0.1-5μm for recesses). These parameter changes ensure that light can be uniformly emitted while the total interface area remains controlled, preventing excessive thermal resistance and heat generation.
2Illumination intensity
If cladding is removed until core is exposed to enable light emission, then light can be emitted from outer peripheral surface, but emission intensity is non-uniform due to refractive index difference between core and air
Solution Approach 1:
The patent creates local quality variations by forming protrusions and recesses on the cladding surface with controlled dimensions. The protrusion height (0.1-10μm) and recess depth (0.1-5μm) are specifically designed to modify the local optical properties, enabling uniform light emission across the outer peripheral surface while maintaining the core-cladding structure.
Solution Approach 2:
The patent applies partial action by selectively removing only portions of the cladding to form protrusions and recesses, rather than completely removing the cladding. This partial modification is sufficient to achieve uniform light emission while preserving the cladding's protective function and maintaining controlled interface area.
3Illumination intensity
If cladding thickness is reduced in light emitting part to enable light emission, then light can be emitted from outer peripheral surface, but thermal resistance increases
Solution Approach 1:
The patent applies local quality by creating protrusions and recesses with controlled dimensions (protrusion height 0.1-10μm, recess depth 0.1-5μm) on the cladding outer peripheral surface in the light emitting part. This local structural modification enables light to be emitted from the outer peripheral surface while maintaining sufficient cladding thickness in the bulk to minimize thermal resistance and heat generation.
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 configuration ensures uniform light emission and reduces heat generation, enhancing treatment efficiency while minimizing damage to healthy tissues during photoimmunotherapy.
Implementation Method 1
an optical fiber including a core located at a center in a radial direction and a cladding adjacent to an outer periphery of the core, the light diffusion device emitting, from a tip side of the optical fiber, light that is incident from a base end portion of the optical fiber. The optical fiber includes: a light transmitting part that transmits, toward a tip, the light that is incident from the base end portion
Implementation Method 2
a light emitting part that, due to removal of an outer peripheral portion of the cladding from the cladding in the tip side, emits, from an outer peripheral surface of the light emitting part, the light transmitted through the light transmitting part
Data Source
AI summary
Provided is a light diffusion device capable of uniformly emitting light from the outer circumferential surface of a light-emitting part of an optical fiber. This light diffusion device 1 comprises an optical fiber 20 composed of a core 21 positioned on the radial center side and a clad 22 positioned on the outer circumferential side of the core 21, and emits laser light, which is incident from a proximal end section of the optical fiber 20, from the distal end side of the optical fiber 20, wherein: the optical fiber 20 has a light transmission part 20a which transmits the laser light incident from the proximal end section toward the distal end section, and a light-emitting part 20b which emits, from the outer circumferential surface, the laser light transmitted from the light transmission part 20a by removing a portion positioned on the outer circumferential side of the clad 22 on the distal end side; and the maximum thickness of the clad 22 in the light-emitting part 20b is smaller than the thickness of the clad 22 in the light transmission part 20a.