Lens Drive Device Electromagnetic Carrier Positioning

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Solution Overview

Problem

Existing lens driving apparatuses in small electronic devices face challenges in maintaining precise lens carrier positioning due to assembly tolerances and deformation from external impacts, leading to potential damage from excessive fluctuation.

Innovation Solution

A lens driving apparatus featuring a housing with a yoke system, electromagnetic interaction between a magnet and coil, and elastic spacers, along with a magnetic member on the carrier to ensure precise positioning and stability against external impacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the carrier is supported by a spring, then the carrier can be positioned, but the carrier may deviate from the precise position due to assembly tolerance and spring deformation

Engineering Contradiction:
Improvecarrier positioning accuracyVSAvoidassembly tolerance
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces the spring-based mechanical support system with an electromagnetic driving system consisting of a magnet and coil. This substitution eliminates the deformation issues inherent in spring mechanisms and assembly tolerances, enabling precise positioning of the carrier through electromagnetic force control rather than mechanical elasticity.

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

Solution Approach 2:

The patent changes the physical state and control parameters from passive mechanical support to active electromagnetic control. By using electromagnetic forces with adjustable intensity and direction, the system can precisely control carrier position without being constrained by spring deformation characteristics or assembly tolerances.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the carrier is supported by a spring, then the carrier can be held in position, but the carrier may be excessively fluctuated by external impact

Engineering Contradiction:
Improvecarrier stabilityVSAvoidexternal impact
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The electromagnetic driving system replaces the spring-based mechanical support, providing active control over carrier stability. The electromagnetic forces can dynamically respond to and counteract external impacts, preventing excessive fluctuation that would occur with passive spring support.

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

Solution Approach 2:

The electromagnetic system can detect and compensate for disturbances autonomously. When external impact causes fluctuation, the electromagnetic driving mechanism can generate counter-forces to stabilize the carrier, providing self-correcting stability without requiring additional mechanical damping elements.

Inventive Principle:
Principle #25Self-service

3Strength

If the carrier is excessively fluctuated by external impact, then the spring may be deformed, but precise positioning is compromised

Engineering Contradiction:
Improvespring durabilityVSAvoidposition accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

By replacing the spring with an electromagnetic driving system, the patent eliminates the spring deformation problem entirely. The electromagnetic mechanism provides precise positioning control without relying on elastic deformation, thereby maintaining both durability and precision simultaneously.

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

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 apparatus effectively maintains the lens carrier in a precise position and prevents excessive fluctuation and damage from external impacts, enhancing the reliability and durability of small electronic device cameras.

Implementation Method 1

a magnet 140 is fixed to an inner peripheral surface of the outer yoke 121 and a coil 150 is fixed to an outer peripheral surface of the carrier 130 while facing the magnet 140. Thus, as current is applied to the coil 150, the coil 150 moves up due to the electromagnetic interaction between the coil 150 and the magnet 140

Methodology Applied
Scientific EffectElectromagnetic interaction: Lorentz Force

Implementation Method 2

A top spacer 161 having a ring shape with elasticity is installed between the top surface of the yoke 120 and the bottom surface of the cover 115, and a bottom spacer 165 having a ring shape with elasticity is installed between the bottom surface of the yoke 120 and the top surface of the base 111. Since the top and bottom spacers 161 and 165 have the elasticity, they can compensate for the dimensional tolerance and assembling tolerance

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2267524B1Lens drive device
Publication Date: 2012.12.19 LG INNOTEK CO LTD
  • EP2267524B1 patent drawingFigure 1~2

AI summary

A lens driving apparatus according to the embodiment includes a housing; a yoke installed in the housing; a magnet fixed to the yoke; a carrier provided inside the yoke to install a lens; a coil coupled with the carrier to interact with the magnet; a spring for elastically supporting the carrier; and a magnetic member coupled to the carrier.