Endoscope Frame Body Segmentation for Thermal Stress Relief
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Solution Overview
Problem
Endoscope apparatuses face issues with the detachment of solid-state image pickup devices due to stress caused by high temperature and pressure during autoclave sterilization, leading to defective images, as existing adhesives expand and impose stress on the bonding between the glass cover and the image pickup device.
Innovation Solution
The endoscope apparatus incorporates a frame body with a fixing region and a non-fixing region, where the glass cover and image pickup device are not directly fixed by the adhesive, allowing for expansion without transmitting stress, and tension in the image pickup cable is managed to reduce detachment risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is used to fix the glass cover and image pickup device together, then the bonding strength is improved, but stress concentration occurs during high temperature autoclave sterilization causing detachment
Solution Approach 1:
The frame body is divided into a fixing region (where adhesive is applied to secure the image pickup device to the frame) and a non-fixing region (where the glass cover and image pickup device are not directly bonded). This segmentation allows the adhesive to provide structural support while avoiding stress concentration at the glass cover bonding interface during thermal expansion.
Solution Approach 2:
The adhesive application is localized to specific regions: it is applied between the image pickup device and frame body in the fixing region, but deliberately avoided in the non-fixing region where the glass cover interfaces with the image pickup device. This creates different bonding characteristics in different locations to accommodate thermal stress differently.
2Ease of manufacture
If the glass cover and image pickup device are directly bonded, then assembly simplicity is improved, but impact resistance and stress distribution are worsened
Solution Approach 1:
The bonding structure is segmented into two functional zones: a fixing region for structural attachment and a non-fixing region for stress relief. This allows the assembly to maintain simplicity while improving impact resistance through strategic placement of adhesive bonds.
Solution Approach 2:
The frame body acts as an intermediary structure between the image pickup device and the glass cover. The fixing region bonds the image pickup device to the frame, while the non-fixing region allows the glass cover to remain relatively independent, with the frame mediating the mechanical connection and stress distribution.
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 enhances the durability of the image pickup unit by preventing stress-induced detachment and maintaining image quality under high temperature conditions, while also improving assemblability and impact resistance.
Implementation Method 1
Respective members and charged adhesives in each endoscope expand under high temperature. At the time of the expansion, stress may be imposed on the part of the bonding between the glass cover and the solid-state image pickup device
Data Source
AI summary
An endoscope apparatus includes: an image pickup device; a glass lid that is provided on a distal end side ahead of a light receiving surface of the image pickup device and is fixed to a front face of the image pickup device in an integrated manner; and a frame body that covers at least a part of the image pickup device and the glass lid. The frame body includes a fixing region for fixing an image pickup circuit portion provided on a proximal end side opposite to the front face of the image pickup device, and a non-fixing region that keeps the distal end side relative to the light receiving surface of the image pickup device and the glass lid fixed to the light receiving surface of the image pickup device in a non-fixed state.