Endoscope Image Pickup Assembly for Thermal Stress Relief

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Solution Overview

Problem

Existing image pickup units at the distal end of endoscopes face challenges in achieving a small diameter while maintaining structural integrity and reliability due to thermal and mechanical stresses.

Innovation Solution

A three-dimensional wiring board with a recess housing a stacked device and filled with sealing resin, where the optical elements and image pickup device are integrated, utilizing a composite element with specific elastic modulus and thermal expansion coefficient relationships to relax stresses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a small-diameter image pickup unit is designed for less invasive endoscopic procedures, then the invasiveness is reduced, but maintaining structural integrity and reliability under thermal and mechanical stresses becomes difficult

Engineering Contradiction:

Improvediameter of image pickup unitVSAvoidstructural integrity under stress

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The patent employs a composite element consisting of a first optical member and a second optical member with different elastic moduli. The first optical member has a higher elastic modulus for structural support, while the second optical member has a lower elastic modulus to absorb thermal and mechanical stresses. This composite structure enables the compact image pickup unit to maintain reliability under stress without increasing diameter.

Inventive Principle:

Principle #40Composite materials

2Length of moving object

If multiple optical elements and image pickup device are integrated in a compact stacked device, then the diameter is reduced, but stress management becomes more challenging

Engineering Contradiction:

Improvediameter of image pickup unitVSAvoidthermal and mechanical stress

Core Design Contradiction:

Length of moving objectVSStress or pressure

Solution Approach 1:

The patent carefully selects materials with specific elastic modulus values for different optical members. The second optical member is designed with an elastic modulus lower than the first optical member and the image pickup device, creating a gradient that progressively absorbs stress. This parameter optimization allows compact integration while managing stress distribution.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The second optical member acts as an intermediary element between the first optical member and the image pickup device. It serves as a stress buffer that absorbs thermal and mechanical stresses before they reach the sensitive image pickup device, enabling reliable compact integration of multiple components.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If sealing resin is used to fill gaps in the compact structure, then structural integrity is improved, but thermal expansion mismatches can cause stress

Engineering Contradiction:

Improvestructural integrityVSAvoidthermal expansion stress

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The patent addresses thermal expansion stress by designing the second optical member with an elastic modulus higher than or equal to the sealing resin. This material property relationship allows the second optical member to constrain the sealing resin's thermal expansion, preventing stress buildup while maintaining the compact structure's integrity.

Inventive Principle:

Principle #37Thermal expansion

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 enhances the reliability and durability of the image pickup unit by absorbing mechanical and thermal stresses, ensuring a compact and robust design suitable for endoscopic applications.

Implementation Method 1

the second optical member has an elastic modulus smaller than an elastic modulus of the first optical member and smaller than an elastic modulus of the image pickup device, and larger than or equal to an elastic modulus of the sealing resin

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

the sealing resin has a thermal expansion coefficient larger than a thermal expansion coefficient of the first optical member and larger than a thermal expansion coefficient of the image pickup device, and smaller than a thermal expansion coefficient of the second optical member

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS12487445B2Image pickup unit and endoscope

Publication Date: 2025.12.02 OLYMPUS MEDICAL SYST CORP

AI summary

An image pickup unit includes: a three-dimensional wiring board having a recess; a stacked device including multiple optical elements and an image pickup device housed in the recess; and sealing resin filling a gap between the recess and the stacked device, in which the multiple optical elements include a composite element having a first optical member and a second optical member disposed on the first optical member, the second optical member has an elastic modulus smaller than an elastic modulus of the first optical member and an elastic modulus of the image pickup device, and larger than or equal to an elastic modulus of the sealing resin, and the sealing resin has a thermal expansion coefficient larger than a thermal expansion coefficient of the first optical member and a thermal expansion coefficient of the image pickup device, and smaller than a thermal expansion coefficient of the second optical member.