Compact Optical Driving Mechanism Control With Inertial Feedback

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Solution Overview

Problem

The challenge of reducing the size and increasing the durability of driving mechanisms in modern electronic devices with image capturing or recording functions, such as smartphones and digital cameras, while maintaining effective auto focus and optical image stabilization, has not been adequately addressed by existing technologies.

Innovation Solution

A control method for a driving mechanism that includes providing electrical signals to a driving assembly to move a movable portion relative to a fixed portion, using a control unit and position sensing unit to calculate and adjust the position, and employing an inertia sensing unit to enhance accuracy and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the driving mechanism is reduced in size to meet modern device requirements, then the device becomes more compact and lightweight, but the durability and precision of the driving mechanism deteriorate

Engineering Contradiction:
Improvesize of driving mechanismVSAvoiddurability of driving mechanism
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent replaces traditional mechanical driving mechanisms with a magnetic driving assembly that uses magnetic fields to move the optical element along the optical axis. This eliminates complex mechanical contact parts, reducing the overall size while improving durability by removing wear-prone mechanical components. The magnetic driving assembly achieves precise positioning without the need for large mechanical structures.

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

Solution Approach 2:

The control assembly integrates multiple functions including position sensing, signal processing, and driving control into a single unified unit. This multi-functional integration reduces the overall size of the driving mechanism while maintaining full functionality for auto-focus and optical image stabilization, thereby improving compactness without sacrificing reliability.

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

2Volume of moving object

If the driving mechanism is reduced in size, then the device becomes more compact, but the manufacturing precision and assembly difficulty increase

Engineering Contradiction:
Improvesize of driving mechanismVSAvoidprecision of driving mechanism
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The magnetic driving assembly replaces mechanical transmission components with magnetic field-based actuation, eliminating the need for precise mechanical tolerances and complex gear trains. This approach maintains high positioning precision while allowing for more relaxed manufacturing tolerances in the overall assembly, thereby improving manufacturability in compact form factors.

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

Solution Approach 2:

The control assembly incorporates a position sensing unit that provides real-time feedback on the position of the optical element. This feedback mechanism enables closed-loop control, ensuring high positioning precision even in the compact magnetic driving assembly. The feedback system compensates for any manufacturing variations and maintains accurate focus and stabilization performance.

Inventive Principle:
Principle #23Feedback

3Volume of moving object

If a magnetic driving assembly is used to reduce size, then the device becomes more compact, but magnetic field interference may corrupt position detection signals

Engineering Contradiction:
Improvesize of driving mechanismVSAvoidmagnetic field interference
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a magnetic shielding structure as an intermediary element between the magnetic driving assembly and the position sensing unit. This shielding structure directs or blocks magnetic field lines to prevent them from reaching the position detection components, thereby eliminating signal corruption while maintaining the compact magnetic driving design.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The control assembly is positioned and oriented to extract or separate the position sensing function from the magnetic field generation zone. By strategically placing the position sensing unit in a location where magnetic field interference is minimal, the system achieves accurate position detection without requiring additional shielding in all areas, thus maintaining compactness.

Inventive Principle:
Principle #2Taking out (Extraction)

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 method enhances the accuracy and durability of the driving mechanism, ensuring precise movement and stability of optical elements, thereby improving auto focus and optical image stabilization in compact electronic devices.

Implementation Method 1

a position sensing unit configured to provide a position signal indicating a position of the movable portion relative to the fixed portion

Methodology Applied
Scientific EffectPosition sensing:

Implementation Method 2

an inertia sensing unit configured to provide a status signal indicating a status of the optical element

Methodology Applied
Scientific EffectInertial sensing:

Data Source

PatentEP3690508B1Control method of driving mechanism
Publication Date: 2025.08.06 TDK TAIWAN
  • EP3690508B1 patent drawingFigure 1
  • EP3690508B1 patent drawingFigure 2
  • EP3690508B1 patent drawingFigure 3

AI summary

A control method of a driving mechanism is provided, including: the driving mechanism provides a first electrical signal from a control assembly to the driving mechanism to move the movable portion into an initial position relative to the fixed portion, wherein the control assembly includes a control unit and a position sensing unit; the status signal of an inertia sensing unit is read; the control unit sends the status signal to the control unit to calculate a target position; the control unit provides a second electrical signal to the driving assembly according to the target position for driving the driving assembly; a position signal is sent from the position sensing unit to the control unit; the control unit provides a third electric signal to the driving assembly to drive the driving assembly according the position signal.