Endoscope Optical Member Bonding via Segmented Metal Welding
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Solution Overview
Problem
Conventional endoscopes face challenges in achieving chemical resistance and reducing diameter, particularly in the distal end portion where optical members are located, due to limitations in adhesive resistance and the need for larger diameters when using lens frames for soldering.
Innovation Solution
The endoscope employs a combination of metal welding and adhesion for bonding optical members, using metal films on the surfaces to improve solder flow and reduce the diameter, with Cr, Ni, and Au metal films for enhanced chemical resistance and watertightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If adhesive bonding is used to fix the optical member to the distal end portion body and cover, then the device complexity is reduced, but the chemical resistance and watertightness deteriorate
Solution Approach 1:
The bonding process is segmented into two distinct stages: first metal welding to establish chemical-resistant and watertight joints between the optical member and distal end portion body, then adhesive bonding to attach the cover. This segmentation allows each bonding method to perform its specialized function optimally.
Solution Approach 2:
Different bonding methods are applied to different locations and interfaces: metal welding is used where chemical resistance and watertightness are critical (optical member to distal end portion body), while adhesive bonding is used where structural flexibility is needed (cover attachment). This local differentiation optimizes overall system performance.
2Reliability
If a lens frame is used for solder bonding the optical member, then the chemical resistance is improved, but the diameter of the distal end portion increases
Solution Approach 1:
The lens frame component is completely removed from the structure. Instead of using a lens frame as an intermediate carrier, the optical member is directly welded to the distal end portion body, eliminating the unnecessary structural element that increased diameter.
Solution Approach 2:
The functions of the lens frame (holding the optical member, providing structural support, enabling solder bonding) are merged directly into the distal end portion body through metal welding, eliminating the need for a separate lens frame component.
3Length of moving object
If metal welding is used to bond the optical member directly without a lens frame, then the diameter is reduced, but the ease of manufacture deteriorates due to solder flow control requirements
Solution Approach 1:
Metal films are deposited on the optical member and distal end portion body surfaces before the soldering process. This preliminary action prepares the surfaces to control solder flow and wetting characteristics, making the subsequent welding process easier to manufacture.
Solution Approach 2:
The surface properties of the bonding interfaces are modified by adding metal films, which change the physical and chemical parameters of the surfaces to optimize solder flow control and manufacturing ease.
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 approach enhances chemical resistance and maintains watertightness while reducing the endoscope's diameter by directly bonding optical members to the distal end portion body and cover without a lens frame, improving the overall durability and functionality.
Implementation Method 1
The portion of the optical member contactably facing one of the first and second members is bonded to the one of the first and second members by metal welding
Implementation Method 2
the portion of the optical member contactably facing the other one of the first and second members is bonded to the other one of the first and second members by adhesion
Data Source
AI summary
An endoscope includes a distal end portion body 31 formed of a metal, a distal end portion cover 32 formed of an insulating resin to cover the distal end portion body 31, and a cover lens 25 disposed at a position at which the circumferential surface of the cover lens 25 is contactable with both the distal end portion body 31 and the distal end portion cover 32. In the above, the proximal end side of the circumferential surface of the cover lens 25 is bonded to the distal end portion body 31 by soldering along the circumferential direction. Meanwhile, the distal end side of the circumferential surface of the cover lens 25 is bonded to the distal end portion cover 32 by adhesion along the circumferential direction. Each of bonding surfaces of the cover lens 25 and the distal end portion body 31 is previously formed with a metal film for improving the flow of a liquid solder.