Image Pickup Module Electrode Layout for Thermal Stress Reduction

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Solution Overview

Problem

Existing image pickup modules face challenges in maintaining high connection reliability and reducing diameter due to thermal energy and mechanical load applied during bonding of conductive wires, which can lead to unnecessary stress on already bonded portions.

Innovation Solution

The image pickup module design features cable electrodes disposed in a region not facing chip electrodes, allowing for separate and controlled bonding processes that avoid applying thermal energy to already bonded areas, using through wirings and sealing resins to enhance mechanical strength and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conductive wires are bonded to cable electrodes using thermal energy, then bonding strength is improved, but thermal stress is applied to already bonded portions between external electrodes and chip electrodes

Engineering Contradiction:

Improvebonding strengthVSAvoidthermal stress

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent divides the bonding process into two separate stages: first bonding external electrodes to chip electrodes, then bonding cable electrodes to conductive wires. By spatially separating these bonding operations and using the wiring board structure, thermal energy is applied to different locations at different times, preventing simultaneous thermal stress on already bonded portions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary bonding of external electrodes to chip electrodes before bonding cable electrodes to conductive wires. This preliminary action allows the first bonding to complete and cool down before applying thermal energy for the second bonding, avoiding thermal stress on the already bonded portions.

Inventive Principle:

Principle #10Preliminary action

2Device complexity

If cable electrodes are disposed facing chip electrodes, then wiring board structure is simplified, but mechanical load is applied to bonding portions during bonding process

Engineering Contradiction:

Improvewiring board structureVSAvoidmechanical load

Core Design Contradiction:

Device complexityVSStress or pressure

Solution Approach 1:

The patent utilizes the third dimension (vertical stacking) by disposing cable electrodes on the rear surface of the wiring board while chip electrodes are on the front surface. This dimensional separation allows both electrode sets to coexist without facing each other, avoiding mechanical load on bonding portions while maintaining a compact structure.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS9455358B2Image pickup module and image pickup unit

Publication Date: 2016.09.27 OLYMPUS CORPORATION(JP)

AI summary

An image pickup module includes: a wiring board including a first main surface on which chip electrodes are disposed and a second main surface on which the cable electrodes connected respectively to the chip electrodes via respective through wirings are disposed; an image pickup device chip including external electrodes bonded respectively to the chip electrodes; and a cable including conductive wires bonded respectively to the cable electrodes, in which all of the cable electrodes are disposed in a region not facing a region where the chip electrodes are disposed.