Lens Driving Device with Spatially Separated Sensing for Camera Modules
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Solution Overview
Problem
Existing camera modules in mobile devices face challenges in achieving precise auto focusing and optical image stabilization, leading to resolution degradation due to user hand-shake and other movement-related issues.
Innovation Solution
A lens driving device with a focusing unit and a movement correction unit is employed, utilizing a carrier with a focusing magnet and coil for axial movement, and a guide member with correction magnets and coils for perpendicular movement, along with a focus sensing portion and movement correction sensing portion for closed-loop control, to accurately focus and stabilize the lens barrel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the focus sensing portion is disposed on the planar surface where focusing magnet and coil are mounted, then the structure is compact, but the driving power for focusing is insufficient
Solution Approach 1:
The focus sensing portion is moved from the planar mounting surface to the side surface of the lens barrel, utilizing a different spatial dimension. This allows the focusing magnet and coil to maintain their planar arrangement for sufficient driving power, while the sensing portion occupies a different spatial location, resolving the conflict between power and complexity
2Reliability
If a single-focus camera module is used, then the structure is simple, but image quality degrades due to hand-shake
Solution Approach 1:
The actuator system is segmented into two independent units: a focusing unit for auto-focusing and a movement correction unit for optical image stabilization. Each unit has its own driving mechanism and sensing portion, allowing them to function independently and simultaneously, thereby improving image quality stability without excessive complexity
3Measurement precision
If the focus sensing portion shares the planar surface with focusing components, then manufacturing is easier, but measurement precision of focus position is reduced
Solution Approach 1:
The focus sensing portion is positioned on the side surface of the lens barrel rather than sharing the planar mounting surface with focusing components. This spatial separation enables each component to be manufactured and assembled independently with higher precision, while the overall assembly remains relatively simple through standardized mounting interfaces
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 solution enhances the camera module's ability to maintain sharp focus and reduce image blurriness caused by user hand-shake, improving image quality by enabling precise movement correction and increased driving power for focusing and stabilization.
Implementation Method 1
a focusing coil disposed to oppose the focusing magnet
Implementation Method 2
a first movement correction coil disposed to oppose the first movement correction magnet and a second movement correction coil disposed to oppose the second movement correction magnet
Implementation Method 3
a focus sensing portion having a focus sensing yoke and a focus sensing coil disposed to oppose the focus sensing yoke
Implementation Method 4
a movement correction sensing portion including a movement correction sensing yoke and a movement correction sensing coil disposed to oppose the movement correction sensing yoke
Data Source
AI summary
A camera module comprises a lens barrel, a lens driving device including a focusing unit moving a lens barrel in an optical axis direction and a movement correction unit moving the lens barrel in a direction perpendicular to the optical axis direction, and a housing accommodating the lens barrel and the lens driving device. A focus sensing portion of the focusing unit is disposed in an area not including a planar surface on which a focusing magnet and a focusing coil are mounted.