Voice Coil Lens Carrier Rolling Guide for Low-Friction Autofocus

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Solution Overview

Problem

Voice coil motor devices face high friction issues during lens focusing or zooming operations due to line contact between guide shafts and hole walls, requiring excessive power and limiting movement precision.

Innovation Solution

A voice coil motor device with a movable magnetic path component and a rollable structure that utilizes magnetic attraction forces and three-point contacts between the component, base, and elongate guide rods, facilitated by balls, to minimize friction and enhance movement travel for precise focusing or zooming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If guide shafts are used for moving the lens carrier, then the lens carrier can be guided along a fixed path, but line contact between the guide shaft and hole wall results in excessive friction

Engineering Contradiction:

Improveguiding accuracyVSAvoidfriction force

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The patent replaces the traditional guide shaft structure with a guide rod that has a curved surface, specifically a cylindrical or slightly tapered shape. This curved surface contacts the lens carrier through point contact rather than line contact, significantly reducing the friction area and friction force while maintaining guiding accuracy through the geometric constraint of the curved surface.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent introduces a magnetic field-based positioning system that supplements or replaces the purely mechanical guide shaft system. Magnetic attraction forces between the guide rod and the lens carrier provide positioning and guiding functions, reducing reliance on mechanical contact and thereby reducing friction.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If guide shafts with line contact are used, then structural simplicity is maintained, but excessive friction requires more driving power

Engineering Contradiction:

Improveguiding structure complexityVSAvoiddriving power

Core Design Contradiction:

Device complexityVSPower

Solution Approach 1:

The guide rod employs a curved cylindrical surface that enables point contact with the lens carrier. This geometric modification reduces the contact area from a line to a point, thereby reducing friction and the driving power required to move the lens carrier, while adding minimal structural complexity.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent incorporates magnetic fields to assist in the guiding and positioning of the lens carrier. This magnetic assistance reduces the mechanical load and friction, thereby reducing the driving power requirement without significantly increasing device complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If guide shafts are used for horizontal movement, then the periscopic camera lens can achieve horizontal focusing or zooming, but similar line contact friction problems occur

Engineering Contradiction:

Improvemovement direction capabilityVSAvoidfriction force

Core Design Contradiction:

Adaptability or versatilityVSForce

Solution Approach 1:

The patent applies the same curved surface guide rod design to both vertical and horizontal movement directions. The guide rod's cylindrical curved surface provides point contact for the lens carrier regardless of movement direction, reducing friction in both vertical focusing and horizontal zooming operations while maintaining the required adaptability.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 solution reduces frictional forces, allowing for more efficient and precise optical focusing and zooming operations by enabling the movable magnetic path component to move with a minimum friction force, increasing movement travel and improving operational efficiency.

Implementation Method 1

the movable magnetic path component, the base and the rollable structure abut against one another by the magnetic attraction force of the magnetic sensing elements and the elongate guide rods

Methodology Applied

Scientific EffectMagnetic attraction force: Magnetism

Implementation Method 2

the plurality of balls facilitate a movement of the movable magnetic path component in the first receiving slot, for performing an auto focusing or zooming of the lens

Methodology Applied

Scientific EffectFriction reduction: Friction

Data Source

PatentUS11747587B2Voice coil motor devices for auto focusing or zooming

Publication Date: 2023.09.05 VASSTEK INT

AI summary

The present invention is related to a voice coil motor device for auto focusing or zooming, mainly includes a base, a movable magnetic path component, two elongate guide rods and a plurality of balls. The base has a first receiving slot and two second receiving slots. The movable magnetic path component is configured in the first receiving slot and has a lens carrier installing thereon a lens, wherein the lens carrier has a bottom surface having a plurality of first abutting structures. The two elongate guide rods are mounted in the two second receiving slots respectively. The plurality of balls are respectively mounted between the plurality of first abutting structures and the two elongate guide rods, wherein the plurality of balls facilitate a movement of the movable magnetic path component in the first receiving slot, for performing an auto focusing or zooming of the lens.