Endoscope Image Pickup Unit Adhesive Hardness Gradient
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Solution Overview
Problem
The existing image pickup units for endoscopes with movable lenses are prone to breakage due to excessive force applied during handling or assembly, and the soft fixing of the lens barrel and drive mechanism portions leads to uncertain positioning of the movable lens holding barrel.
Innovation Solution
An image pickup unit design that includes a lens barrel portion with a movable lens holding barrel and a drive mechanism portion, where a holding portion on the side surface of the lens barrel positions and holds the drive mechanism, and the gap between the lens barrel and drive mechanism is filled with adhesive of varying hardness, with higher hardness on the distal end and lower hardness on the proximal end to enhance fixation and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the drive mechanism portion is disposed apart from the lens barrel portion with a gap, then the positioning of the movable lens holding barrel is improved, but the fixing portion becomes vulnerable to breakage from excessive force
Solution Approach 1:
The adhesive is designed with varying hardness at different locations: harder at the distal end for strong fixation and softer at the proximal end for shock absorption. This local differentiation of material properties allows the fixing portion to simultaneously achieve strong attachment and resistance to breakage from excessive force during assembly or maintenance.
Solution Approach 2:
The patent uses a composite adhesive structure with two different adhesive materials having distinct hardness characteristics. The harder adhesive provides rigid fixation for positioning accuracy, while the softer adhesive provides flexibility and shock absorption, creating a composite fixing system that resolves the contradiction between positioning precision and breakage resistance.
2Strength
If the adhesive is made uniformly hard, then the fixation strength is improved, but the drive mechanism portion cannot move relative to the lens barrel portion causing misregistration
Solution Approach 1:
The adhesive hardness varies by location: the distal end uses harder adhesive to provide strong fixation and prevent misregistration, while the proximal end uses softer adhesive to allow controlled relative movement between the drive mechanism portion and lens barrel portion. This local differentiation enables both stable positioning and necessary flexibility for operation.
Solution Approach 2:
The adhesive system transitions from a static, uniform hardness design to a dynamic configuration where different regions have different compliance characteristics. The softer proximal adhesive allows the drive mechanism to move relative to the lens barrel during operation, while the harder distal adhesive maintains precise positioning, enabling the system to adapt its rigidity based on operational requirements.
3Adaptability or versatility
If the adhesive is made uniformly soft, then the flexibility is improved, but the positioning accuracy of the movable lens holding barrel deteriorates
Solution Approach 1:
The adhesive hardness is differentiated by location: the proximal end uses softer adhesive to provide flexibility and absorb shocks, while the distal end uses harder adhesive to ensure precise positioning of the movable lens holding barrel. This spatial variation in adhesive properties allows the system to simultaneously achieve both flexibility and positioning accuracy.
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 design effectively prevents breakage of the fixing portion by allowing the drive mechanism to move relative to the lens barrel without misregistration, ensuring precise positioning and durability of the image pickup unit.
Implementation Method 1
the gap between the lens barrel portion and the drive mechanism portion is filled with an adhesive which is made to have a difference in hardness such that hardness becomes lower toward a proximal end side
Data Source
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AI summary
According to this invention, there is provided an image pickup unit for an endoscope, including a lens barrel portion which is configured to hold an objective lens including a movable lens and an image pickup device and includes a movable lens holding barrel that holds the movable lens and is movable to advance and retract and a drive mechanism portion which is disposed at a side surface portion of the lens barrel portion and drives the movable lens holding barrel. The unit has a holding portion which is disposed at the side surface portion of the lens barrel portion and is configured to position and hold the drive mechanism portion, the drive mechanism portion is shaped to extend in a direction toward a proximal end with a gap with the lens barrel portion on a side closer to the proximal end than the holding portion, and the gap between the lens barrel portion and the drive mechanism portion is filled with an adhesive which is made to have a difference in hardness such that hardness becomes lower toward a proximal end side.