Lens Moving Apparatus Inductive Position Detection

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Solution Overview

Problem

The existing lens moving apparatuses in camera modules face challenges with increased manufacturing costs and complexity due to the need for additional position detecting sensors, which restrict the linear range of output and require additional components, making it difficult to achieve accurate AF feedback control and wider linearity.

Innovation Solution

A simplified structure using a bobbin with a first coil and a magnet, supported by a housing with elastic members and a second coil that generates induction voltage through inductive interaction, allowing for wider linearity and more accurate AF feedback control without the need for additional position detecting sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an additional position detecting sensor is used to detect displacement of the bobbin, then measurement precision is improved, but device complexity increases due to additional PCB and mounting structures

Engineering Contradiction:

Improvedisplacement detection precisionVSAvoidstructure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the position detecting sensor and PCB into an integrated unit that is directly mounted on the bobbin, eliminating the need for separate mounting structures and reducing overall device complexity while maintaining detection precision

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The PCB is designed to serve multiple functions: mounting the position detecting sensor, providing electrical connections, and serving as a structural support element, thereby reducing the need for additional components

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If an additional position detecting sensor is used, then measurement precision is improved, but manufacturing cost increases due to complicated structure

Engineering Contradiction:

Improvedisplacement detection precisionVSAvoidmanufacturing cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent integrates the position detecting sensor and PCB into a compact assembly that reduces component count and assembly steps, thereby lowering manufacturing costs while maintaining detection precision

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The bobbin structure is designed to incorporate the PCB and sensor mounting features directly, allowing the component to serve its own mounting and support functions without requiring external structures

Inventive Principle:

Principle #25Self-service

3Measurement precision

If additional components are provided for sensor mounting, then measurement precision is improved, but the space required increases making it difficult to realize a lens having large diameter

Engineering Contradiction:

Improveposition detection accuracyVSAvoidspace required

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The position detecting sensor is mounted directly on the bobbin structure, nesting the sensor within the existing mechanical framework rather than requiring external mounting space, thus preserving lens diameter

Inventive Principle:

Principle #7Nested doll (Nesting)

4Device complexity

If the positional relationship between the position detecting sensor and magnet is fixed, then device complexity is reduced, but linearity range becomes extremely restricted

Engineering Contradiction:

Improvestructure simplicityVSAvoidlinearity range

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent employs a magnetic field distribution design that dynamically adapts to bobbin displacement, maintaining linear output characteristics over a wider range through optimized magnet and sensor positioning that accounts for movement variations

Inventive Principle:

Principle #15Dynamics

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 solution reduces manufacturing costs and facilitates more accurate AF feedback control by enabling wider linearity and reducing the defect rate, eliminating the need for additional position detecting sensors and simplifying the structure of the lens moving apparatus.

Implementation Method 1

a second coil disposed so as to be spaced apart from the first coil in the first direction, wherein the second coil generates induction voltage resulting from inductive interaction with the first coil when the bobbin moves in the first direction

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS11653103B2Lens moving apparatus and camera module and portable terminal including the same

Publication Date: 2023.05.16 LG INNOTEK CO LTD

AI summary

Embodiments provide a lens moving apparatus including a housing supporting a magnet, a bobbin having an outer circumferential surface on which a first coil is disposed, the bobbin moving in the housing in a first direction, upper and lower elastic members each connected to both the housing and the bobbin, and a second coil disposed so as to be spaced apart from the first coil in the first direction, wherein the second coil generates induction voltage resulting from inductive interaction with the first coil when the bobbin moves in the first direction.