Endoscope Defogging via Nanoparticle Photothermal Heating
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Solution Overview
Problem
Endoscope fogging due to condensation on the optical window reduces visibility during surgical procedures, with existing solutions either disrupting the procedure or adding bulk and complexity to the endoscope.
Innovation Solution
An endoscope with a cover window made of an optically clear material doped with metal nanoparticles or nanorods that selectively absorbs light to heat the lens, combined with a machine learning algorithm to detect and mitigate fogging by adjusting the light source emission profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If forced convection by flowing air is used to mitigate fogging, then fogging is reduced, but the endoscope diameter increases and complexity is added
Solution Approach 1:
The patent replaces the mechanical forced convection system (requiring bulk and flow channels) with a photothermal system using light-absorbing nanoparticles embedded in the optical window coating. This substitution eliminates the need for mechanical air flow components while achieving the same fogging mitigation effect through optical energy conversion to thermal energy.
Solution Approach 2:
The patent changes the physical-chemical parameters of the optical window by embedding light-absorbing nanoparticles (such as iron oxide, gold, or silver nanoparticles) into the coating layer. This modifies the optical properties of the window to selectively absorb specific wavelengths of light, converting optical energy to thermal energy to prevent condensation without requiring structural modifications to the endoscope.
2Object-affected harmful factors
If the endoscope window temperature is raised above dew point to prevent condensation, then visibility is maintained, but additional heating mechanisms increase device complexity
Solution Approach 1:
The optical window performs its primary function of transmitting light while simultaneously serving a secondary function of heating itself through the photothermal effect of embedded nanoparticles. The window absorbs specific wavelengths of light (particularly in the infrared range) and converts this energy to heat, maintaining its own temperature above the dew point without requiring external heating mechanisms.
Solution Approach 2:
The optical window coating is designed to perform multiple functions: transmitting visible light for imaging while simultaneously absorbing infrared light for thermal management. The nanoparticle-enhanced coating acts as both an optical element and a heating element, eliminating the need for separate heating components and reducing overall device complexity.
3Temperature
If light-absorbing materials are added to the optical window to heat it, then fogging is prevented, but the window's optical clarity may be compromised
Solution Approach 1:
The patent applies local quality by embedding nanoparticles selectively in specific regions or layers of the optical window coating. The coating structure is designed so that nanoparticles are positioned to absorb infrared light while minimizing interference with visible light transmission. This localized modification allows different parts of the optical system to have different properties: the nanoparticle-containing regions provide thermal management, while the overall coating maintains optical clarity for imaging.
Solution Approach 2:
The optical window uses a composite material structure combining transparent coating materials (such as silicon dioxide, titanium dioxide, or zinc oxide) with light-absorbing nanoparticles (iron oxide, gold, or silver). This composite structure leverages the complementary properties of each component: the transparent matrix maintains optical clarity while the nanoparticle inclusions provide selective light absorption and photothermal heating to prevent condensation.
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
Effectively maintains clear visibility by raising the optical window temperature above the dew point, minimizing fogging without disrupting surgical procedures or increasing endoscope bulk, using a feedback algorithm to adjust light emission based on fog severity.
Implementation Method 1
An endoscope with a cover window made of an optically clear material doped with metal nanoparticles or nanorods that selectively absorbs light to heat the lens
Data Source
AI summary
An endoscope includes a light source coupled to emit light, and a lens disposed proximate to a distal tip of the endoscope tube and structured to absorb at least some of the light. A controller is coupled to the light source, and the controller includes logic that when executed by the controller causes the endoscope to perform operations, including adjusting an emission profile of the light source to heat the lens with the light, and heating the lens mitigates formation of fog on the lens.