Eddy Current Shake Correction Device for Lens Hysteresis
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Solution Overview
Problem
Existing shake correction devices for cameras, such as those used in mobile phones, suffer from hysteresis phenomena due to the poor recovery nature of damping materials, leading to shifts in the lens position during swinging, which results in unintended image capture.
Innovation Solution
A shake correction device utilizing rectangle board-shaped permanent magnets disposed around the optical axis at 90-degree intervals, combined with a brake member featuring eddy current induction plates and an electromagnetic shield board, which generates eddy currents to mitigate vibrations and impacts without damping materials, preventing hysteresis and enhancing impact endurance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If damping material is used to suppress vibration and impact, then vibration suppression is improved, but hysteresis phenomenon occurs causing lens position shift
Solution Approach 1:
The patent replaces the mechanical damping material with an electromagnetic braking system consisting of eddy current induction plates and permanent magnets. This substitution eliminates the hysteresis phenomenon inherent in mechanical damping materials while maintaining effective vibration suppression through electromagnetic forces.
Solution Approach 2:
The patent changes the physical mechanism from mechanical deformation (damping material) to electromagnetic interaction (eddy currents). By inducing eddy currents in conductive plates through magnetic field changes from permanent magnets, the system achieves vibration damping without the position drift caused by material hysteresis.
2Reliability
If damping material is used to improve impact endurance, then impact resistance is improved, but hysteresis causes unintended image capture
Solution Approach 1:
The patent replaces mechanical damping with electromagnetic braking to maintain impact endurance while eliminating hysteresis. The eddy current induction plates and permanent magnets create a non-contact braking system that provides consistent stopping force without the position drift that causes unintended image capture.
Solution Approach 2:
The patent introduces eddy current induction plates as an intermediary between the moving lens assembly and the fixed structure. These plates interact with permanent magnets to provide braking force during impact, protecting the system while maintaining precise lens positioning through non-contact electromagnetic forces.
3Reliability
If conventional shake correction structure is used, then shake correction function is achieved, but device complexity increases
Solution Approach 1:
The patent merges the vibration suppression function and the electromagnetic drive function into a single integrated structure. The eddy current induction plates are positioned to work with the permanent magnets that also provide the driving force, eliminating the need for separate damping components and reducing overall structural complexity.
Solution Approach 2:
The permanent magnets and eddy current induction plates serve multiple functions: they provide the electromagnetic driving force for shake correction and simultaneously act as the braking mechanism for vibration and impact suppression. This multi-functionality reduces the number of components needed in the system.
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 effectively suppresses unnecessary resonance and improves impact endurance by generating a braking force through eddy currents, maintaining the center position of the photographed object and preventing hysteresis, thus ensuring stable image capture.
Implementation Method 1
the at least one eddy current induction plate generates eddy currents in response to a magnetic field caused by the shift of the permanent magnets
Implementation Method 2
the shield cover 39 can shield electromagnetic waves leaked from the outside or emitted from an image sensor
Implementation Method 3
The lens driving device for automatic focus is used to generate Lorentz force to shift the lens holder 38 in the Z axis direction
Data Source
AI summary
The present invention provides a shake correction device which can not generate the hysteresis phenomenon and can suppress unnecessary resonance and improve endurance with respect to drop impact. In this shake correction device, the eddy current induction plate 16a of +Z side is opposite to and has a gap with the surface (14a) of the +Z side of the permanent magnet (14) which is arranged to wind around the optical axis at an interval of 90 degree in the Z direction, the eddy current induction plate 16b of radial direction is opposite to and has a space with the surface (14b) of the outside in the radial direction, and the eddy current induction plate 16c of the periphery direction is opposite to and has a gap with the surface (14c) in the periphery direction.