Lens Module on Rigid-Flex PCB with Clearance Glue

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Solution Overview

Problem

Conventional camera lens modules face challenges such as increased thickness, high production costs, and reduced yield rates due to complex assembly processes and inadequate packaging technologies, which hinder the miniaturization of camera lenses in thin electronic products.

Innovation Solution

A lens module is designed using a rigid-flex PCB unit comprising two rigid PCBs and a thinner flex PCB in between, with a lens and image sensor attached to the flex PCB, and clearance glue filling gaps between components, eliminating the need for connectors or welding and forming an integral, thin structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If conventional packaging technologies (CSP, COB, flip chip) are used, then lens modules can be manufactured, but the module height increases and production cost increases

Engineering Contradiction:

Improvelens module heightVSAvoidproduction cost

Core Design Contradiction:

Length of moving objectVSEase of manufacture

Solution Approach 1:

The rigid PCB is divided into two separate rigid PCBs with a flex PCB connecting them, creating a rigid-flex structure that allows the lens module to be mounted on the thinner flex PCB portion, thereby reducing overall module height while maintaining manufacturing feasibility

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A flex PCB is introduced as a thin flexible substrate between two rigid PCBs, enabling the lens module to be mounted on the thin flex PCB section which reduces the overall height of the lens module while maintaining electrical connectivity and structural support

Inventive Principle:

Principle #30Flexible shells and thin films

2Adaptability or versatility

If the number of superposed parts increases, then lens module functionality is enhanced, but the final fit tolerance becomes larger and imaging effect is influenced

Engineering Contradiction:

Improvelens module functionalityVSAvoidfinal fit tolerance

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

Multiple components (lens, image sensor, filter, and rigid PCBs) are merged into a single integrated assembly on the flex PCB, where the flex PCB serves as a common mounting platform that precisely positions all components relative to each other, thereby maintaining tight tolerances even as the number of components increases

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The flex PCB acts as an intermediary platform between the two rigid PCBs and all mounted components, providing a flexible yet precise mounting surface that accommodates multiple components while maintaining relative positioning accuracy through its inherent flexibility and precision manufacturing capabilities

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If conventional COB packaging with hot bar soldering is used, then lens modules can be assembled, but reliability decreases

Engineering Contradiction:

Improveassembly processVSAvoidassembly reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The conventional hot bar soldering process is replaced with a mechanical bonding approach where the flex PCB is bonded to the two rigid PCBs through adhesive bonding or other non-soldering mechanical connections, eliminating the reliability issues associated with hot bar soldering while maintaining ease of assembly

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The assembly method transitions from thermal-soldering processes to chemical-bonding or mechanical-bonding processes, changing the fundamental bonding parameter from temperature/heat to adhesive strength or mechanical attachment, thereby improving reliability while maintaining manufacturability

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

The solution reduces the overall thickness of the camera lens module while enhancing yield rates and structural integrity, addressing the limitations of existing packaging technologies by creating a robust and compact lens module.

Implementation Method 1

a type of clearance glue is filled in the clearances. With the clearance glue, joints between the flex PCB and the two rigid PCBs are reinforced

Methodology Applied

Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentUS11711891B2Lens module mounting on rigid-flex printed circuit board

Publication Date: 2023.07.25 JIASHAN WANSHUNDA ELECTRONICS CO LTD

AI summary

A lens module mounted on rigid-flex printed circuit board (PCB) includes a rigid-flex PCB unit having two rigid PCBs and a flex PCB connected to between the two rigid PCBs, and an image sensor and a lens mounted on the flex PCB. A clearance is formed between the lens and the two rigid PCBs, and is filled with clearance glue. The clearance glue reinforces joints of the flex PCB and the two rigid PCBs, and the lens module becomes an integral structure after the clearance glue is cured.