Dual-Guide Lens Actuator for Low-Friction Zoom Alignment

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Solution Overview

Problem

Existing camera modules face issues such as increased friction torque, lens decent or tilt, reduced magnetic force, and reliability problems due to impacts between the lens housing and stoppers, which affect image quality and zooming functionality, especially in compact designs.

Innovation Solution

The lens actuator includes a guide rail with metal stoppers and a rolling driving unit using balls for minimal friction, a yoke integrated within the coil unit to enhance magnetic force, and a dual-function magnet for precise positioning, all integrated into a compact camera module design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a lens housing is driven by mechanical movement using a lens actuator for zooming function, then the zooming function is achieved, but friction torque increases and power consumption increases

Engineering Contradiction:

Improvezooming functionVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent replaces the traditional mechanical contact-based lens actuator with a magnetic field-based actuator. The lens housing includes a magnet and the actuator includes a coil that generates a magnetic field to drive the lens housing along the optical axis, eliminating mechanical friction and reducing power consumption while maintaining the zooming function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a magnetic fluid (ferrofluid) as the medium between the magnet and the coil. This magnetic fluid transmits the magnetic field force while providing cooling and lubrication, enabling the lens housing to move smoothly without mechanical contact, thus reducing friction torque and power consumption.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Manufacturing precision

If the lens housing is stopped by a stopper at the limit of movement range, then the movement range is controlled, but impact occurs causing lens decent or tilt

Engineering Contradiction:

Improvemovement range controlVSAvoidlens alignment

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent replaces the mechanical stopper system with a magnetic field-based positioning system. The magnetic field provides continuous force control that can precisely position the lens housing at the limits of its movement range without physical contact, eliminating impact forces that cause lens decent or tilt.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses the magnetic field to apply a preliminary counteracting force before the lens housing reaches the physical stopper. This prevents the lens housing from impacting the stopper by neutralizing the momentum before contact occurs, thereby preventing lens decent or tilt.

Inventive Principle:

Principle #9Preliminary anti-action

3Measurement precision

If the yoke is disposed on the rear side of the coil unit, then the initial position of the lens housing can be controlled, but the magnetic force between the yoke and the magnet is weak

Engineering Contradiction:

Improveinitial position controlVSAvoidmagnetic force

Core Design Contradiction:

Measurement precisionVSForce

Solution Approach 1:

The patent introduces magnetic fluid as an intermediary between the yoke and the magnet. This magnetic fluid enhances the magnetic field coupling, allowing the yoke to exert sufficient magnetic force on the magnet from the rear side of the coil unit while maintaining precise initial position control of the lens housing.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 design reduces friction torque, prevents lens decent and tilt, enhances magnetic force, and improves image quality and resolution while enabling smooth zooming functions in compact camera modules.

Implementation Method 1

a rolling driving unit using balls for minimal friction

Methodology Applied

Scientific EffectFriction reduction through rolling contact: Ball Bearing

Implementation Method 2

a yoke integrated within the coil unit to enhance magnetic force

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

a dual-function magnet for precise positioning

Methodology Applied

Scientific EffectMagnetic force: Magnetism

Data Source

PatentUS20250355217A1Lens actuator and a camera module including the same

Publication Date: 2025.11.20 LG INNOTEK CO LTD

AI summary

A lens actuator includes a base, a first guide rail disposed within the base, a second guide rail disposed within the base, a first lens assembly configured to move in an optical axis direction along the first guide rail, a second lens assembly configure to move in the optical axis direction along the second guide rail, a first magnet disposed on one side of the first lens assembly, a first coil unit spaced apart from the first magnet and disposed within the base, and a first ball disposed between the first lens assembly and the first guide rail. The first guide rail includes a first guide recess. A length of the first guide recess is greater than a length of the first lens assembly. The first guide rail and the second guide rail are diagonally disposed within the base on a plane perpendicular to the optical axis.