Lens Positioning Correction for Disturbance Magnetic Fields

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Solution Overview

Problem

Optical modules with lens positioning systems face errors in position detection due to external disturbance magnetic fields, leading to instability in camera shake correction and autofocus functions.

Innovation Solution

A driving apparatus that includes a magnetic field detection section, a storage section for reference information, and a control section to correct the magnetic field information, allowing the actuator to accurately position the lens despite external disturbances by comparing detected magnetic field data to pre-stored reference information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If magnetic field detection is used to detect lens position, then position detection is enabled, but position detection accuracy deteriorates due to external disturbance magnetic fields

Engineering Contradiction:

Improvelens position detection accuracyVSAvoidexternal disturbance magnetic field influence

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent stores reference magnetic field information in advance when no disturbance magnetic field is present. This preliminary action creates a baseline that can be used for comparison during operation, allowing the system to detect and correct for disturbance magnetic fields by comparing current readings against the stored reference data.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback control by comparing the magnetic field detection result with the stored reference information, calculating a correction value, and using this correction to adjust the lens position control. This closed-loop feedback mechanism continuously compensates for disturbance magnetic fields to maintain accurate positioning.

Inventive Principle:

Principle #23Feedback

2Reliability

If feedback control is performed using magnetic field detection results, then lens positioning control is achieved, but positioning accuracy deteriorates when disturbance magnetic fields are present

Engineering Contradiction:

Improveoptical camera shake correction stabilityVSAvoidlens position detection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent modifies the feedback control by introducing a correction value calculation step. The control section compares the magnetic field detection result with stored reference information, calculates the difference as a correction value, and applies this correction to the feedback control signal, ensuring reliable operation even under disturbance magnetic fields.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the control parameter by introducing a correction value that adjusts the magnetic field detection result. This parameter modification allows the system to compensate for disturbance magnetic fields dynamically, maintaining reliable optical camera shake correction and autofocus functions.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If magnetic field information is used directly for control, then simple control is achieved, but lens positioning accuracy deteriorates due to disturbance magnetic fields

Engineering Contradiction:

Improvecontrol simplicityVSAvoidlens position detection accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent maintains control simplicity by automatically calculating the correction value through feedback comparison and applying it transparently to the control process. The system remains easy to operate while internally compensating for disturbance magnetic fields through the feedback mechanism, without requiring complex manual intervention.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent enables the system to self-correct for disturbance magnetic fields by automatically comparing detection results with stored reference information and applying corrections without external intervention. This self-service capability maintains both simplicity of operation and accuracy simultaneously.

Inventive Principle:

Principle #25Self-service

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 stabilizes the operation of optical camera shake correction and autofocus functions by reducing the influence of disturbance magnetic fields, ensuring accurate lens positioning and maintaining system performance.

Implementation Method 1

a magnetic field detection section that detects magnetic field information corresponding to the relative position between the lens section and the imaging device

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentUS11347024B2Driving apparatus, lens unit, device, and correction method for external disturbance magnetic field

Publication Date: 2022.05.31 ASAHI KASEI MICRODEVICES CORP

AI summary

A driving apparatus, a lens unit, a device, a correction method, and a computer readable recording medium are provided, the driving apparatus including an actuator that changes a relative position between a lens section and an imaging device; a magnetic field detection section that detects magnetic field information corresponding to the relative position between the lens section and the imaging device; a storage section that stores reference information that is based on an output of the magnetic field detection section when the lens section or the imaging device is positioned at the reference position; and a control section that controls a driving amount of the actuator based on the magnetic field information and the reference information.