Lens Unit Drive Sections Asymmetric Positioning for Thrust Balance
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Solution Overview
Problem
Existing lens units with auto-focus functions face challenges in maintaining balance and efficiently transmitting thrust due to the positioning of drive sections, leading to inefficiencies in lens movement and increased size.
Innovation Solution
A lens unit design featuring first and second lens drive sections with voice coil motors, where the magnets are biased to the end portions of yokes and positioned to maintain balance, allowing efficient thrust transmission without increasing the lens unit's size, by ensuring the center point connecting line does not pass through the lens axis, and using cam grooves and pins for movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If multiple drive sections are mounted on the support frame to increase driving force, then the driving force for lens movement is increased, but the lens barrel increases in size
Solution Approach 1:
Multiple drive sections (first and second lens drive sections) are mounted on the support frame to combine their driving forces. The drive sections are positioned at different locations but work together to move the lens holder along the optical axis, achieving increased driving force without proportionally increasing the overall lens barrel size.
Solution Approach 2:
The drive sections are disposed at positions where their center point connecting line does not pass through the lens axis, creating an asymmetric arrangement in the radial dimension. This dimensional positioning allows the drive sections to contribute to axial movement through mechanical coupling while occupying radial space that would otherwise be unused, thereby increasing driving force without significantly increasing the axial length of the lens barrel.
2Volume of moving object
If drive sections are disposed to avoid cam pins, then the lens barrel size is suppressed, but the centroid position of the support frame deviates from the lens axis center causing imbalance
Solution Approach 1:
The drive sections are intentionally disposed asymmetrically such that their center point connecting line does not pass through the lens axis. This asymmetric arrangement allows the drive sections to be positioned at locations that do not overlap with cam pins when viewed in the axial direction, suppressing lens barrel size while the asymmetric configuration is compensated to maintain functional balance.
Solution Approach 2:
The balance of the support frame is maintained not by symmetric positioning of all components, but by ensuring that the drive sections are positioned to provide balanced thrust generation. The local positioning of drive sections is optimized to achieve both size reduction and functional balance, where the thrust balance is maintained through careful selection of drive section positions and their coupling mechanism to the lens holder.
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 design effectively maintains thrust balance and transmits force efficiently, enabling high-speed lens movement without increasing the lens unit's size, while preventing resonance and ensuring smooth operation.
Implementation Method 1
each of the first and second lens drive sections includes a voice coil motor that includes a yoke fixed to one of the lens holder and the support frame, a voice coil fixed to the other thereof and facing the yoke
Implementation Method 2
a plate-like magnet fixed to a surface of the yoke facing the voice coil
Data Source
AI summary
First and second lens drive sections of the lens unit are disposed at positions where a center point connecting line, which connects center positions of the lens drive sections on a plane perpendicular to a lens axis, does not pass through the lens axis; and include yokes, voice coils, and plate-like magnets. The width of the magnet in a lens circumferential direction is smaller than the width of the yoke; and the magnets are disposed to be biased to end portions of the yokes, which are positioned in a divided area in which a lens axis center is present, of divided areas divided into two by a center point connecting line, in the lens circumferential direction, respectively. The shortest distance between an operating point connecting line is shorter than the shortest distance between the center point connecting line and the lens axis.