Lens Drive Device Gravity Center Triangle Stabilization

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Solution Overview

Problem

Existing lens drive devices face challenges in stabilizing the movement of movable objects during operation, leading to potential looseness and instability, especially when the direction of the lens drive device is changed.

Innovation Solution

A lens drive device design incorporating X-axis and Y-axis actuators with piezoelectric elements and drive shafts, along with friction engagement and support portions, is used to stabilize the movement of movable objects by positioning the gravity centers within specific triangles, ensuring stable movement in multiple directions without dependence on the device's orientation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the lens drive device uses friction engagement portions and support portions to hold movable objects, then the movable objects can be stably moved in specific directions, but the device becomes complex and the stability becomes dependent on orientation

Engineering Contradiction:

Improvestability of movable object movementVSAvoidcomplexity of holding structure

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The holding structure is segmented into multiple discrete components: friction engagement portions (first and second) and support portions (first and second), each performing specific functions. This segmentation allows independent optimization of each component's stability contribution while managing overall structural complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the movable object are given different local qualities through the strategic placement of friction engagement portions at specific locations (e.g., outer circumferential surfaces of drive shafts) and support portions at other locations, creating orientation-dependent stability characteristics that ensure stable movement in intended directions

Inventive Principle:

Principle #3Local quality

2Stability of the object's composition

If the gravity center is positioned within a specific triangle formed by contact portions, then stable movement is achieved in a specific orientation, but the device cannot maintain stability when rotated or changed in orientation

Engineering Contradiction:

Improvestability of movable object movementVSAvoidadaptability to orientation changes

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The holding structure employs asymmetric configuration where friction engagement portions and support portions are positioned at specific asymmetric locations relative to the movable object's geometry. This asymmetry creates orientation-sensitive stability characteristics that can be optimized for specific operational orientations

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The gravity center positioning acts as a counterbalancing mechanism, strategically placed within the triangle formed by contact portions to counteract destabilizing forces and maintain stability in intended orientations, while the asymmetric structure prevents stability in rotated orientations

Inventive Principle:

Principle #8Anti-weight (Counterweight)

3Ease of operation

If friction engagement portions are used to engage with drive shafts, then movement control is improved, but looseness occurs and stability deteriorates

Engineering Contradiction:

Improveease of movement controlVSAvoidreliability of movement stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The friction engagement portions are merged with support portions to form an integrated holding system. This combination allows the friction engagement to work synergistically with mechanical support, providing both ease of movement control through friction and reliability through structural support, eliminating the looseness that would occur with friction engagement alone

Inventive Principle:

Principle #5Merging (Combining)

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 design enables stable movement of X-axis and Y-axis movable objects, maintaining stability even when the lens drive device is rotated, by effectively suppressing looseness and restricting movement ranges through stopper mechanisms, thus ensuring reliable operation.

Implementation Method 1

an X-axis piezoelectric element expanding and contracting in an X-axis direction orthogonal to a direction of an optical axis of the lens

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a Z-axis friction engagement portion frictionally engaging with outer circumference of the Z-axis drive shaft

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS10247956B2Lens drive device

Publication Date: 2019.04.02 TDK CORP

AI summary

A gravity center obtained by combining a gravity center of an X-axis movable object, a gravity center of a Y-axis movable object, and a gravity center of a lens carrier is located in a triangle, as vertexes, having a contact portion in which an X-axis friction engagement portion comes into contact with an X-axis drive shaft, a contact portion in which a first X-axis support portion comes into contact with an X-axis movable object holding portion, and a contact portion in which a second X-axis support portion comes into contact with the X-axis movable object holding portion.