Camera Module Voice-Coil Focusing to Prevent Vibration Banging

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional camera modules in mobile phones experience a thud noise due to the lens unit rocking during vibration mode, caused by the spring supporting the lens unit, which results in a banging sound when the mobile phone vibrates.

Innovation Solution

A camera module design incorporating a bobbin with a coil and magnet system, where a reverse current is applied to the coil to push the lens unit onto a tension member, preventing the lens unit from rocking during vibration mode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a spring supports the lens unit in a conventional camera module, then the lens unit can move along the optical axis for auto focusing, but the spring causes the lens unit to rock during vibration mode, generating banging sounds

Engineering Contradiction:

Improveauto focusing capabilityVSAvoidbanging sound in vibration mode

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent removes the spring component from the camera module and replaces it with a voice coil motor system. This extraction of the problematic spring element eliminates the rocking motion that causes banging sounds during vibration mode, while the voice coil motor provides the necessary lens unit movement for auto focusing through electromagnetic force.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical spring-based focusing mechanism with an electromagnetic voice coil motor system. The voice coil motor uses electromagnetic interaction between a coil and magnet to drive the lens unit along the optical axis, substituting the mechanical spring system that caused vibration-related banging sounds.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If a voice coil motor is used to move the lens unit, then auto focusing is achieved, but the lens unit remains vulnerable to rocking during phone vibration

Engineering Contradiction:

Improveauto focusing capabilityVSAvoidstability during vibration mode

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent merges the voice coil motor components (coil and magnet) into an integrated assembly with the lens unit. The coil is wound around a bobbin that is coupled to the lens unit, and the magnet is positioned within the yoke structure. This integrated design ensures that the electromagnetic driving force and the lens unit move together as a unified system, improving stability during vibration.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent applies reverse current to the coil in advance when vibration mode is detected, which pushes the lens unit onto the tension member before significant rocking occurs. This preliminary action secures the lens unit in a stable position, preventing the rocking motion that would otherwise generate banging sounds during vibration.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If the lens unit is allowed to move freely for focusing, then focusing functionality is maintained, but the lens unit touches the bottom surface during vibration, causing noise

Engineering Contradiction:

Improvefocusing functionalityVSAvoidbanging sound from lens contact

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a tension member as an intermediary element between the lens unit and the bottom surface of the housing. The tension member provides a controlled stopping point for the lens unit during vibration, preventing direct contact between the lens unit and the hard bottom surface that would generate banging sounds, while still allowing the lens unit to move freely for focusing operations.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Inventive Principle:

Principle #10Preliminary action

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 design effectively inhibits the banging sound by securely positioning the lens unit during vibrations, ensuring smooth operation without noise.

Implementation Method 1

a coil wound on the bobbin, the bobbin moving to two directions based on a current applied to the coil; a magnet configured to interact the coil

Methodology Applied

Scientific EffectElectromagnetic interaction: Lorentz Force

Data Source

PatentUS12445546B2Camera module and mobile phone using the same

Publication Date: 2025.10.14 LG INNOTEK CO LTD

AI summary

Disclosed herein is a camera module comprising: a circuit board; a frame coupled to the circuit board; an image sensor on the circuit board; a bobbin on the frame, a plurality of lenses being inside the bobbin; a coil wound on the bobbin, the bobbin moving to two directions based on a current applied to the coil; a magnet configured to interact the coil; and a yoke on the frame, the magnet being at an inner side of the yoke, wherein the bobbin moves to a first direction when a forward current is applied to the coil and to a second direction when a reverse current is applied to the coil.