Lens Drive Ball-Guided Layout for Low-Power Autofocus

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Solution Overview

Problem

Conventional lens driving devices in camera devices face increased power consumption and size issues due to the use of heavier magnets in the moving part, which is exacerbated by higher pixelation and increased lens diameter, leading to protrusion from smartphones.

Innovation Solution

A lens driving device design that incorporates a lighter coil in the moving unit, utilizing a configuration with multiple moving units and drive units to minimize size and power consumption, including a bobbin and guide frame with specific ball arrangements for precise movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If magnets are disposed in the moving part for autofocus function, then the autofocus function can be performed, but the current consumption increases due to the heavier weight of magnets compared to coils

Engineering Contradiction:
Improveautofocus functionVSAvoidcurrent consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent inverts the conventional arrangement by placing the coil in the moving part and the magnet in the fixed part. This reversal allows the electromagnetic interaction to remain functional for autofocus while significantly reducing the weight of the moving part, thereby lowering current consumption.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent replaces the conventional magnetic actuation system with an electromagnetic coil-based system in the moving part. This substitution enables the same autofocus function to be achieved with lighter components, reducing the mechanical load and energy requirements.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If magnets and coils are disposed for autofocus and handshake correction functions, then both functions can be performed, but the device size in optical axis direction increases causing protrusion from smartphone

Engineering Contradiction:
Improveautofocus and handshake correction functionsVSAvoiddevice size in optical axis direction
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent designs the moving part to perform multiple functions - both autofocus (via the coil interacting with the fixed magnet) and handshake correction (via the guide frame interacting with another fixed magnet). This multi-functionality eliminates the need for separate magnetic components, reducing the overall device length.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the autofocus and handshake correction mechanisms into a single integrated moving part structure. By combining these functions in one assembly with shared components, the patent reduces the total space required in the optical axis direction, preventing protrusion from the smartphone.

Inventive Principle:
Principle #5Merging (Combining)

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

Reduces current consumption for autofocus functions and minimizes the camera device's size in the optical axis direction, enabling both autofocus and handshake correction without protrusion from smartphones.

Implementation Method 1

Autofocus and handshake correction functions can be performed through the electromagnetic interaction between the magnet and the coil

Methodology Applied
Scientific EffectElectromagnetic interaction: Lorentz Force

Implementation Method 2

Autofocus and handshake correction functions can be performed through the electromagnetic interaction between the magnet and the coil

Methodology Applied
Scientific EffectElectromagnetic interaction: Lorentz Force

Data Source

PatentEP4597189A1Lens driving device, camera device, and optical device
Publication Date: 2025.08.06 LG INNOTEK CO LTD
  • EP4597189A1 patent drawingFigure 1
  • EP4597189A1 patent drawingFigure 2~3
  • EP4597189A1 patent drawingFigure 4~5

AI summary

The present embodiment relates to a lens driving device comprising: a base; a housing arranged on the base; a guide frame arranged in the housing; a bobbin arranged in the guide frame; a first ball arranged between the base and the housing; a second ball arranged between one side surface of the guide frame and the side surface of the housing; and a third ball arranged between the side surface of the bobbin and the other side surface of the guide frame.