Fingerprint Module Sealing via Adhesive and Nesting

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Solution Overview

Problem

Existing fingerprint modules face safety issues due to poor sealing between circuit boards and fingerprint chips, leading to corrosion, contamination, and impurity mixing, which compromises the module's integrity.

Innovation Solution

A fingerprint module design that includes a fingerprint chip with an identifying surface and a connecting surface, where a circuit board is coupled to the connecting surface with a sealing adhesive positioned between them, and a conductive surface attached to the connecting surface, creating a sealed environment to prevent corrosion and contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a fingerprint chip and circuit board are connected without complete integration, then the module structure is simpler, but sealing performance deteriorates leading to corrosion and contamination

Engineering Contradiction:
Improvemodule structureVSAvoidsealing performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The circuit board is designed with a recessed region that accommodates the fingerprint chip, creating a nested structure where the chip is inserted into the circuit board's recessed area. This nesting approach provides inherent sealing without requiring complete integration, thus maintaining structural simplicity while improving sealing performance.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

A sealing adhesive is introduced as an intermediary material between the fingerprint chip and circuit board. This adhesive fills the gaps and interfaces between the two components, providing effective sealing against corrosion and contamination while allowing the components to remain separately integrated.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If sealing adhesive is added between circuit board and fingerprint chip, then sealing performance improves, but manufacturing complexity increases

Engineering Contradiction:
Improvesealing performanceVSAvoidmanufacturing process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The circuit board is pre-formed with a recessed region during the circuit board manufacturing process, before the fingerprint chip is attached. This preliminary structuring simplifies the subsequent assembly process by providing a ready-made sealing cavity that guides the placement and sealing of the fingerprint chip.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The sealing adhesive is applied specifically at the interface between the fingerprint chip and the recessed region of the circuit board, rather than uniformly across the entire assembly. This localized application of sealing material reduces waste and simplifies the manufacturing process while maintaining effective sealing at the critical interface.

Inventive Principle:
Principle #3Local quality

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 effectively prevents corrosion, contamination, and impurity mixing, thereby enhancing the safety and reliability of the fingerprint module by maintaining a stable and sealed environment for the circuit board and fingerprint chip.

Implementation Method 1

a sealing adhesive is positioned between the circuit board and the fingerprint chip... the sealing adhesive is disposed between the connecting surface and the peripheral side surface

Methodology Applied
Scientific EffectSealing:

Data Source

PatentEP3291515B1Fingerprint module, method for fabricating the same, and mobile terminal
Publication Date: 2020.02.12 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD
  • EP3291515B1 patent drawingFigure 1
  • EP3291515B1 patent drawingFigure 2
  • EP3291515B1 patent drawingFigure 3

AI summary

Disclosed are a fingerprint module, a method for fabricating the same, and a mobile terminal. The fingerprint module has a fingerprint chip and a circuit board. The fingerprint chip has an identifying surface and a connecting surface opposite to the identifying surface, wherein the identifying surface is configured to identify a fingerprint of a user. The circuit board is attached to the connecting surface, wherein a sealing adhesive is disposed between the circuit board and the fingerprint chip.