Optical Element Drive Device Position Detection via Magnetic Field Interaction

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Solution Overview

Problem

Conventional optical element drive devices face accuracy issues in detecting the position of a lens holder due to changes in external environments, such as temperature, affecting the reliability of position detection.

Innovation Solution

The optical element drive device incorporates a movable section with a first magnetic field generator and a fixed section with a sensor unit that detects the interaction between the first magnetic field and a bias magnetic field, ensuring accurate position detection regardless of environmental changes by utilizing a combined magnetic field analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a magnetic detection device is used to detect the position of the lens holder, then the position can be detected, but the detection accuracy decreases due to changes in external environment such as temperature

Engineering Contradiction:

Improveposition detection accuracyVSAvoiddetection reliability under environmental changes

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent changes the detection parameter from measuring only magnetic field strength to measuring the interaction between magnetic field strength and bias field. By detecting the combined effect of the first magnetic field (from sensor magnet) and bias magnetic field (from drive magnet), the system can determine position based on the relationship between these fields rather than absolute field strength, making the detection immune to temperature-induced field strength variations

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The bias magnetic field generated by the drive magnet serves as an intermediary reference field. This bias field acts as a stable reference that, when combined with the sensor magnet's field, creates a detection signal that reflects position changes without being affected by environmental temperature variations. The bias field mediates between the sensor magnet and the detection system to eliminate temperature sensitivity

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 approach enhances the detection accuracy of the movable section's position relative to the fixed section, maintaining reliability even with external environmental fluctuations, and allows for precise control of the lens holder's movement.

Implementation Method 1

a movable section including a first magnetic field generator for generating a first magnetic field

Methodology Applied

Scientific EffectMagnetic field generation: Magnetic Field

Implementation Method 2

the sensor unit carries out a detection based on the first magnetic field and a bias magnetic field different from the first magnetic field

Methodology Applied

Scientific EffectMagnetic field interaction detection: Magnetic Field

Data Source

PatentUS11567289B2Optical element drive device

Publication Date: 2023.01.31 ACTUTEK CORP

AI summary

An optical element drive device includes a movable section and a fixed section. The movable section includes a first magnetic field generator for generating a first magnetic field and is drivable in a motion direction. The fixed section includes a sensor unit. The sensor unit carries out a detection based on the first magnetic field and a bias magnetic field different from the first magnetic field.