Endoscope Optical Adhesion via Low-Expansion Resin Buffer
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Solution Overview
Problem
Existing endoscope designs fail to adequately consider the thermal expansion of adhesives and external shock resistance, leading to insufficient adhesion strength between optical components, particularly at high temperatures and under mechanical stress.
Innovation Solution
An endoscope design featuring an adhesive layer between optical members and a resin layer that fills the gap between them, with a thermal expansion coefficient of the resin layer set to 1/10 or less of the adhesive layer, ensuring enhanced adhesion strength and reliability by preventing separation due to thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If adhesive is used to adhere optical members in a small space, then the components can be mounted in compact arrangement, but the adhesive layer becomes vulnerable to thermal expansion and shock forces
Solution Approach 1:
The patent uses a composite structure consisting of two different resin materials with different thermal expansion coefficients. The first resin material (adhesive layer) has high adhesion to optical members, while the second resin material (resin layer) has low thermal expansion coefficient to counteract thermal stress. This composite material approach resolves the contradiction by combining materials with complementary properties.
Solution Approach 2:
The patent changes the thermal expansion parameter by introducing a resin layer with a thermal expansion coefficient that is 1/10 or less of the adhesive layer's coefficient. This parameter modification allows the structure to maintain adhesive bond strength despite thermal expansion forces, resolving the contradiction between compact mounting and reliability.
2Manufacturing precision
If adhesive layer is made thin to reduce gap, then mounting precision improves, but the adhesive layer becomes more susceptible to thermal expansion damage
Solution Approach 1:
The patent introduces a resin layer as an intermediary between the adhesive layer and the gap. This resin layer acts as a buffer that absorbs thermal expansion forces, protecting the thin adhesive layer from damage while maintaining the precision gap control. The intermediary layer resolves the contradiction by providing mechanical protection without compromising precision.
Solution Approach 2:
The patent applies different material properties to different regions: the adhesive layer has high adhesion quality for bonding optical members, while the resin layer has low thermal expansion quality for stress resistance. This local differentiation of material qualities allows the thin adhesive layer to maintain both precision and strength.
3Adaptability or versatility
If components are mounted in distal end portion under high temperature, then endoscope functionality is maintained, but thermal expansion of adhesive causes adhesion failure
Solution Approach 1:
The patent directly addresses thermal expansion by introducing a resin layer with a thermal expansion coefficient that is 1/10 or less of the adhesive layer's coefficient. This resin layer compensates for thermal expansion forces during high-temperature operation, preventing adhesion failure while maintaining endoscope functionality.
Solution Approach 2:
The patent changes the thermal parameter of the assembly by adding a material with fundamentally different thermal expansion characteristics. This parameter change enables the adhesive bond to remain stable under high-temperature conditions, resolving the contradiction between adaptability and reliability.
4Ease of manufacture
If adhesive layer is used alone to fill gap, then manufacturing simplicity is maintained, but adhesion strength is insufficient under external shock
Solution Approach 1:
The patent uses a composite resin structure where the first resin material provides adhesion and the second resin material provides shock resistance. This composite approach enhances adhesion strength under external shock while maintaining relatively simple manufacturing processes.
Solution Approach 2:
The resin layer with low thermal expansion coefficient acts as a pre-established cushion against thermal and mechanical stresses. This beforehand cushioning protects the adhesive layer from shock forces, enhancing adhesion strength without complicating the manufacturing process.
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
The solution effectively enhances the adhesion strength between optical members, improving the endoscope's reliability and performance under high-temperature and mechanical stress conditions by controlling thermal expansion and reinforcing the adhesive bond.
Implementation Method 1
an influence of the thermal expansion of the adhesive, which adheres these components, needs to be considered... A thermal expansion coefficient of the resin layer is set to 1/10 or less of a thermal expansion coefficient of the adhesive layer
Data Source
AI summary
There are provided an endoscope in which adhesion strength between two optical members can be enhanced and an endoscope apparatus including the endoscope. An endoscope includes an insertion part that is to be inserted into a subject, a first unit that is built in a distal end portion of the insertion part and includes a prism, a second unit that is built in the distal end portion and includes a cover glass, an adhesive layer that is formed between the light-emitting surface of the prism and the surface of the cover glass and adheres the prism to the cover glass, and a resin layer that fills a gap larger than the thickness of the adhesive layer formed between the first unit and the second unit. The thermal expansion coefficient of the resin layer is set to 1/10 or less of the thermal expansion coefficient of the adhesive layer.