Flattened Light Guide Layout for Slim Arthroscope Illumination
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Solution Overview
Problem
Existing endoscopes face challenges with reusability, leading to increased costs and risks of cross-infection due to imperfect sterilization, as well as issues with optical degradation and fouling during multiple uses.
Innovation Solution
Designing endoscopes with partially reusable and partially disposable components, including a detachable shaft with a disposable cap and handle, and utilizing poka-yoke design principles for correct assembly, along with fiber optics and LED illumination to ensure sterility and reduce optical artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If endoscopes are designed for multiple uses, then productivity and cost-effectiveness improve, but reliability deteriorates due to sterilization imperfections and optical degradation
Solution Approach 1:
The endoscope is divided into reusable components (handle, illumination system) and disposable components (shaft with camera). This segmentation allows the critical imaging and illumination parts to be sterilized and reused, while the shaft that contacts bodily fluids is discarded after single use, eliminating sterilization concerns for the disposable portion.
Solution Approach 2:
The shaft including the camera is designed as a disposable component that is discarded after single use. This eliminates all concerns about sterilization imperfections and optical degradation from repeated use, as the disposable shaft is replaced rather than reused.
2Ease of operation
If the shaft diameter is reduced to improve ease of insertion, then ease of operation improves, but device complexity increases due to tighter tolerances and more difficult assembly
Solution Approach 1:
By separating the shaft into disposable and reusable segments with standardized interfaces, the design simplifies assembly. The disposable shaft can be pre-assembled with its components and then quickly attached to the reusable handle, reducing the complexity of assembling all components to tight tolerances.
Solution Approach 2:
The disposable shaft and its components are pre-assembled and pre-sterilized as a unit before use. This preliminary assembly allows for quality control and sterilization of the critical path components separately from the reusable parts, simplifying the overall assembly process.
3Reliability
If disposable components are used to ensure sterility, then reliability improves, but manufacturing costs increase
Solution Approach 1:
The endoscope is segmented into high-value reusable components (handle, illumination system requiring precision optics) and low-value disposable components (shaft with camera). This segmentation allows the expensive reusable parts to be manufactured once and sterilized repeatedly, while the disposable shaft is manufactured at lower cost and discarded after use.
Solution Approach 2:
The disposable shaft is discarded after single use to ensure sterility, while the reusable handle and illumination system are recovered, sterilized, and reused across multiple procedures. This recovers the high manufacturing costs of the complex optical and electronic components.
4Illumination intensity
If light conductors are positioned close to the camera to maximize illumination, then illumination intensity improves, but optical artifacts increase due to reflections and light leakage
Solution Approach 1:
A light guide is introduced as an intermediary component between the illumination light source and the camera. The light guide conducts light from the illumination source past the camera to the distal end, allowing illumination to be positioned close to the camera for maximum intensity while the light guide's optical design (with proper indexing and surface treatment) prevents harmful reflections and light leakage.
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 design reduces manufacturing costs, improves patient safety by ensuring disposability of components in contact with bodily fluids, and maintains optical clarity and functionality by minimizing reuse-related issues.
Implementation Method 1
The light guide has an optical fiber that extends through the second component. The converter is coupled to the proximal end such that the primary and secondary light is injected into the optical fiber, is conducted from the proximal end to the distal end, and emitted at the distal end.
Implementation Method 2
The arthroscope has a handle and an insertion shaft. The insertion shaft has near its distal end a solid state camera.
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
An arthroscope's insertion shaft has near its distal end a solid state camera. The shaft has an outer diameter of no more than 6mm, and has rigidity and strength for insertion of the camera into joints for arthroscopic surgery. Light conductor(s) have a flattened region shaped to lie between an endoscope camera and an inner surface of an outer wall of an endoscope shaft. The flattened region is shaped to conduct illumination light though the space between the camera and inner surface of the other wall to a distal end of the endoscope shaft for illumination of a surgical cavity to be viewed by the camera. The flattened region is formed by heating a region of a plastic optical fiber, and squeezing the heated region in a polished mold.