Camera Module Adhesive Bonding for Thermal Misalignment

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Solution Overview

Problem

The existing imaging devices face challenges in accurately adjusting the optical axis due to deviations caused by fastening forces and thermal stress, leading to misalignment and errors in distance measurement.

Innovation Solution

The use of adhesives as fastening means instead of screws, with a combination of temporary and main adhesives to secure the camera module to the housing, reducing optical axis misalignment by managing thermal deformations and environmental changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a fastening member such as a screw is used to attach the camera module to the housing, then the camera module can be securely fixed, but the fastening force causes deviation in the optical axis position and rotational direction

Engineering Contradiction:
Improvefastening forceVSAvoidoptical axis position accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical fastening system (screws) with an adhesive bonding system. The adhesive layer bonds the camera module holder to the housing without applying concentrated mechanical fastening forces, thereby eliminating the deviation in optical axis position and rotational direction that occurs with screw fastening while still providing secure fixation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Strength

If screws are used for fastening, then the camera module can be securely attached, but thermal stress causes the fastening portion to slip and reduces reproducibility

Engineering Contradiction:
Improvefastening strengthVSAvoidreproducibility of optical axis alignment
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The adhesive bonding system replaces the mechanical screw fastening system, eliminating the slip phenomenon that occurs under thermal stress. The adhesive layer distributes thermal stresses uniformly and maintains consistent bonding strength across temperature changes, thereby improving the reproducibility of optical axis alignment and eliminating the instability associated with mechanical fastening.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If adhesive is used instead of screws, then optical axis misalignment is reduced, but the fastening strength may be insufficient

Engineering Contradiction:
Improveoptical axis alignment accuracyVSAvoidfastening strength
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent optimizes adhesive bonding parameters including selecting appropriate adhesive materials with suitable bonding strength, controlling adhesive layer thickness, and optimizing curing conditions. These parameter changes ensure that the adhesive bonding provides both high optical axis alignment accuracy and sufficient fastening strength to securely attach the camera module to the housing.

Inventive Principle:
Principle #35Parameter changes

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 stabilizes the camera module's position and reduces optical axis misalignment, ensuring accurate and stable distance measurements despite temperature changes.

Implementation Method 1

a camera module 102 is attached to a housing 101 by adhesive 56

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

the fastening force of the fastening member is transmitted to the pressurized camera module, which may cause the deviation in rotational direction of the axis and the deviation in the optical axis position at the time of fastening... a large thermal stress is generated against temperature change

Methodology Applied
Scientific EffectThermal stress distribution: Thermal Expansion

Data Source

PatentEP3614204B1Imaging device
Publication Date: 2023.11.22 ASTEMO LTD
  • EP3614204B1 patent drawingFigure 1(a)~1(b)
  • EP3614204B1 patent drawingFigure 2
  • EP3614204B1 patent drawingFigure 3

AI summary

The purpose of the present invention is to provide a stereo-camera capable of reducing optical axis misalignment from, for instance, thermal deformations due to the differences in thermal expansion at ambient temperature between a housing and an imaging element module. The present invention comprises: an imaging element module 102 including a lens barrel 2 and a holder 1 around the lens barrel 2; and a housing 101 that holds the imaging element module 102. The housing 101 has a support 6 for supporting the holder 1 in the imaging element module 102. The holder 1 is held by the housing 101 via a first bonding region 13 between supports 6a, 6b and the lens barrel 2 and a second bonding region 14 located closer to the lens barrel 2 than the first bonding region 13.