Interferometric Force Sensor for Microsurgical Tools
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Solution Overview
Problem
Current surgical instruments for microsurgical applications, such as retinal surgery, face challenges in accurately measuring tool-to-tissue forces due to limitations in force sensing technology, particularly in small diameters and within the eye, where existing solutions like FBG sensors face issues with manufacturing complexity, stiffness, and signal noise, leading to reduced sensitivity and calibration problems.
Innovation Solution
The integration of an interferometric optical sensor system, including Fabry-Perot interferometers, which measures changes in reference distance to detect forces and torques applied to the surgical tool, providing improved sensitivity and accuracy through optical coupling and compliant materials, allowing for precise force and torque measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If FBG sensors are used in small-diameter surgical tools, then force sensing capability is provided, but manufacturing complexity and stiffness increase, reducing sensitivity
Solution Approach 1:
The patent replaces FBG (Fiber Bragg Grating) optical fiber sensors with interferometric optical sensors that use mechanical compliance to detect forces. The compliant section with flexures converts force into measurable displacement, eliminating the need for complex FBG manufacturing and attachment processes while maintaining force sensing capability in small-diameter tools.
Solution Approach 2:
The patent employs a compliant section made of flexible materials with integrated flexures that deform under applied forces. This flexible structure allows the sensor to accommodate small diameter constraints while providing accurate force measurement through displacement, avoiding the stiffness and manufacturing complexity issues of FBG sensors.
2Measurement precision
If FBG sensors are used in small-diameter surgical tools, then force sensing capability is provided, but signal noise increases, reducing sensitivity
Solution Approach 1:
The patent replaces FBG optical fiber sensors with interferometric optical sensors that use mechanical compliance to detect forces. The compliant section with flexures converts force into measurable displacement, eliminating the need for complex FBG manufacturing and attachment processes while maintaining force sensing capability in small-diameter tools.
3Measurement precision
If force sensors are placed in the handle of surgical tools, then force measurement is achieved, but tool-to-sclera interaction forces mask tool-to-tissue forces
Solution Approach 1:
The patent segments the surgical tool into distinct sections: a body section, a compliant sensor section with interferometric sensors, and a surgical section. This segmentation allows the sensor to be positioned in the middle section, isolated from both sclera interaction forces at the handle and tissue forces at the tip, enabling accurate measurement of tool-to-tissue forces without contamination from scleral forces.
4Adaptability or versatility
If sensor diameter is reduced for integration into small surgical tools, then tool compatibility is improved, but measurement precision deteriorates
Solution Approach 1:
The patent employs a compliant section made of flexible materials with integrated flexures that deform under applied forces. This flexible structure allows the sensor to accommodate small diameter constraints while providing accurate force measurement through displacement, avoiding the stiffness and manufacturing complexity issues of FBG sensors.
Solution Approach 2:
The patent replaces FBG optical fiber sensors with interferometric optical sensors that use mechanical compliance to detect forces. The compliant section with flexures converts force into measurable displacement, eliminating the need for complex FBG manufacturing and attachment processes while maintaining force sensing capability in small-diameter tools.
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 solution enhances the precision and reliability of force and torque measurements in microsurgical tools, reducing ambiguity and improving surgical outcomes by providing accurate feedback to surgeons, thus addressing the limitations of existing technologies.
Implementation Method 1
an interferometric optical sensor defining a reference distance that changes in response to at least one of a force or a torque when applied to the surgical section of the surgical tool
Implementation Method 2
including Fabry-Perot interferometers, which measures changes in reference distance to detect forces and torques applied to the surgical tool
Data Source
AI summary
A surgical tool system according to an embodiment of the current invention includes a surgical tool, and an interferometry system optically coupled to the surgical tool. The surgical tool includes a body section, a sensor section at least one of attached to or integral with the body section, and a surgical section at least one of attached to or integral with the sensor section at an opposing end of the sensor section from the body section. The sensor section comprises an interferometric optical sensor defining a reference distance that changes in response to at least one of a force or a torque when applied to the surgical section of the surgical tool.