Voice Coil Motor Bobbin Rotation Prevention
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Solution Overview
Problem
Conventional voice coil motors suffer from damage or bending of the leaf spring and poor assembly due to rotational forces when mounting a lens to a bobbin using a screw thread, leading to uncontrollable distance adjustments between the image sensor and lens.
Innovation Solution
A voice coil motor design featuring a bobbin with intermittently protruded second bobbins and a rotation prevention unit, such as grooves or plates, to prevent the bobbin from rotating, coupled with elastic members for support, ensuring the lens is securely mounted without damaging the leaf spring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the lens is mounted to the bobbin using a screw thread formed at an inner surface of the bobbin, then the lens can be securely fixed to the bobbin, but the bobbin is generated with a rotational force by rotation of the lens, whereby the lens and the bobbin are rotated by the rotational force
Solution Approach 1:
The patent introduces asymmetric features (protrusions and grooves) on the bobbin that interact with corresponding features on the leaf spring. This asymmetric design allows the lens to be securely fixed while preventing the bobbin from rotating during the mounting process, as the asymmetric features engage to restrict rotational movement.
Solution Approach 2:
The patent introduces an intermediate structure (the combination of protrusions and grooves) between the lens mounting process and the bobbin-leaf spring interface. This intermediate mechanism transfers and restricts rotational forces, preventing them from being transmitted to the leaf spring while still allowing secure lens fixation.
2Ease of manufacture
If the bobbin is rotated, then the lens can be mounted to the bobbin, but a leaf spring of an extremely thin metal plate coupled to the bobbin and elastically supporting the bobbin is simultaneously rotated, and the leaf spring is thereby damaged or bent
Solution Approach 1:
The patent applies preliminary anti-action by pre-configuring the protrusions and grooves on the bobbin before the lens mounting process. These features are designed to counteract and prevent the rotational force that would otherwise be generated during lens mounting, thereby protecting the leaf spring from damage before the harmful rotation can occur.
Solution Approach 2:
The patent converts the potentially harmful rotational force into a beneficial locking mechanism. The protrusions and grooves are designed to engage in a way that the rotational movement intended for mounting is instead converted into a secure, non-rotational fixed position, protecting the leaf spring while achieving mounting.
3Ease of manufacture
If the bobbin is designed with a simple cylindrical shape, then the manufacturing is easier, but the bobbin cannot prevent rotation during lens mounting
Solution Approach 1:
The patent applies local quality by adding protrusions and grooves only at specific locations on the bobbin surface, rather than changing the entire bobbin structure. This allows the majority of the bobbin to maintain its simple cylindrical shape for easy manufacturing, while the localized asymmetric features provide the necessary rotation control functionality.
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
Prevents bobbin rotation during lens mounting, thereby avoiding damage to the elastic members and ensuring accurate, reliable assembly of the voice coil motor, enhancing its operational stability and assembly quality.
Implementation Method 1
an elastic member elastically supporting the bobbin
Implementation Method 2
A voice coil motor uses a repulsive force and an attractive force generated by a magnetic field of a magnet and a magnetic field of coil
Implementation Method 3
a repulsive force and an attractive force generated by a magnetic field of a magnet and a magnetic field of coil
Data Source
AI summary
A voice coil motor is disclosed, the motor including: a mover including a bobbin including a first bobbin having a lens secured therein and a plurality of second bobbins intermittently protruded from an upper surface of the first bobbin, and a coil block secured to a periphery of the first bobbin; a stator including a magnet facing the coil block and a yoke securing the magnet; a case including a bottom case formed with the bobbin and an upper case coupled to the bottom case and having a portion that is correspondingly opened to the bobbin; and an elastic member elastically supporting the bobbin, wherein any one of the yoke and the upper case is formed with a rotation prevention unit extended to the plurality of second bobbins in order to prevent the bobbin from rotating.