Lens Driving Device Feedback Control and Coil Support
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Solution Overview
Problem
Existing lens moving apparatuses face challenges with accurate auto focusing, torque control, noise reduction, mechanical resonance, and increased manufacturing costs due to open loop control methods and mechanical vibrations.
Innovation Solution
A lens moving apparatus employing a feedback control method with a cover member, bobbin, winding ring, coil, and flexible circuit board, which reduces vibrations and mechanical resonance, and omits upper and lower elastic members to simplify the structure and lower manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If open loop control method is used with elastic member supporting the bobbin, then the structure is simple, but the position control accuracy is insufficient and auto focusing time is long
Solution Approach 1:
The patent implements a feedback control system using a position sensor to detect the bobbin position and a magnet to generate magnetic field signals. The control unit processes these feedback signals to accurately determine bobbin position and adjust the voice coil motor accordingly, resolving the position control accuracy issue while maintaining relatively simple structure through intelligent control algorithms.
Solution Approach 2:
The patent replaces the traditional mechanical elastic member support system with a magnetic field-based voice coil motor system. This substitution eliminates mechanical contact and friction, enabling more precise position control through electromagnetic force while reducing mechanical complexity.
2Device complexity
If coil is directly wound around the bobbin, then the structure is compact, but the bobbin shrinks due to heat and tension making torque control difficult
Solution Approach 1:
The patent separates the coil winding from the bobbin structure by introducing a distinct voice coil assembly. The coil is wound around a non-magnetic former rather than directly on the bobbin, dividing the system into independent functional components. This segmentation prevents heat and tension from the coil from affecting the bobbin dimensions, ensuring precise torque control while maintaining compact overall structure.
3Ease of manufacture
If adhesive is used to fix coil block to bobbin, then the assembly is simple, but the coil block may separate and adhesive management is difficult
Solution Approach 1:
The patent replaces adhesive bonding with mechanical attachment methods such as snap-fits, clips, or integrated mounting structures. The coil block is securely fixed to the bobbin through physical interlocking mechanisms that provide reliable attachment without the variability and management issues associated with adhesive application, while maintaining assembly simplicity through designed mechanical features.
4Ease of operation
If elastic member is used to support bobbin movement, then the bobbin is elastically supported, but noise is generated and mechanical resonance occurs
Solution Approach 1:
The patent replaces the mechanical elastic member support system with a magnetic field-based suspension and positioning system. The voice coil motor uses electromagnetic forces to support and position the bobbin without mechanical contact, eliminating the noise and mechanical resonance generated by elastic members while maintaining smooth bobbin movement through controlled magnetic fields.
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 apparatus achieves accurate auto focusing, reduces noise and mechanical resonance, and lowers manufacturing costs by using a flexible circuit board for electrical conduction and a winding ring to prevent coil deformation, thereby enhancing the precision and efficiency of lens movement.
Implementation Method 1
a coil wound around the outer circumferential surface of the winding ring for supplying current to the bobbin such that the bobbin is moved in the first direction
Implementation Method 2
a first magnet provided in the cover member for moving the bobbin in the first direction
Data Source
AI summary
One embodiment of a lens driving device may comprise: a cover member; a bobbin which is disposed within the cover member so as to be movable in a first direction; a first magnet which is disposed within the cover member to move the bobbin in the first direction; a winding ring which is coupled to the bobbin; a coil which is wound around the outer circumferential surface of the winding ring and applies current for the movement of the bobbin in the first direction; a base which is coupled to the lower end of the cover member; and a flexible circuit board which is disposed on the lower side of the bobbin so as to be electrically connected with the coil.