Compact Lens Driving Device with Simplified Coil Configuration
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Solution Overview
Problem
Conventional lens driving devices with shake suppression functions have complex structures and low driving efficiency due to multiple coil ends and inefficient coil arrangements, which hinder the production of sharp images in vari-focal camera modules.
Innovation Solution
A compact lens driving device with a simplified assembly process, featuring a driving coil configuration with only six coil ends, where coils are wound around the lens holder's circumference, and permanent magnets are arranged to enhance Lorentz forces for effective shake suppression and auto-focus operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coils are allocated to the sides of the lens holder with eight coil ends, then shake suppression function is achieved, but the structure becomes complex
Solution Approach 1:
The driving coil is divided into multiple independent coils (first coil, second coil, third coil) wound around the lens holder circumference. Each coil can be independently controlled to generate specific Lorentz forces for different shaking directions, enabling comprehensive shake suppression while maintaining a modular and manageable structure.
Solution Approach 2:
The coils are arranged in a circumferential configuration around the lens holder rather than linearly on one side. This three-dimensional arrangement allows the coils to counteract shaking forces from multiple directions simultaneously, achieving comprehensive shake suppression with a more compact and symmetric structure.
2Ease of operation
If coils are wound around an axis perpendicular to the optical axis, then the lens holder can be driven, but the driving efficiency is low
Solution Approach 1:
The coils are wound around the circumferential surface of the lens holder, following its curved geometry. This curved arrangement optimizes the magnetic field distribution and Lorentz force generation, improving the coupling between the driving coil and permanent magnets, thereby enhancing driving efficiency while maintaining ease of operation.
3Reliability
If multiple permanent magnets are arranged around the Z axis, then Lorentz forces are enhanced for shake suppression, but the assembly process becomes more difficult
Solution Approach 1:
The permanent magnets are arranged in an asymmetric pattern around the Z axis with specific spacing relationships. The first and fourth magnets face the first coil, the second magnet faces the first and second coils, and the third magnet faces the second and third coils. This asymmetric arrangement optimizes the Lorentz force distribution for effective shake suppression while establishing a repeatable assembly pattern.
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 provides a compact, high-efficiency lens driving device capable of suppressing shakes and ensuring sharp images by effectively controlling the Lorentz forces acting on the lens holder, thereby improving image quality in vari-focal camera modules.
Implementation Method 1
the configuration of the driving coil including a first through third coils wound around the Z axis is such that the second coil is arranged in the forward direction of the Z axis with respect to the first coil and the third coil is arranged in a backward direction of the Z axis with respect to the first coil, and that the permanent magnets include a first through fourth magnets whose polarity at respective sides facing the driving coil is the same
Implementation Method 2
A lens driving device includes a lens holder holding a lens assembly; a casing disposed outside of the lens holder and connected with the lens holder by a spring member to retain the lens holder; a driving coil mounted on an outer circumference of the lens holder; and a permanent magnet mounted on the casing and arranged opposite to and separated from the driving coil with spacing
Data Source
AI summary
The present invention provides a simple and compact lens driving device with a shake suppression function. In a VCM lens driving device 10, the driving coil 15 mounted on the outer circumference of the lens holder 11 includes a first through third coils 15a-15c, and the permanent magnet 16 mounted on the casing 13 and opposite to the driving coil 15 with spacing includes a first through fourth magnets 161-164. The first magnet 161 and the second magnet 162 are facing the first coil 15a at the middle of the lens holder 11; the third magnet 163 is facing the first coil 15a and the second coil 15b at the imaged-object side of the first coil 15a; the fourth magnet 164 is facing the first coil 15a and the third coil 15c at the opposite side to the imaged-object side of the first coil 15a.