Camera Module Lens Drive With Integrated AF and Shake Correction
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Solution Overview
Problem
Existing camera modules face challenges in achieving miniaturization, low power consumption, and accurate focusing while effectively correcting handshake vibrations, especially in ultracompact designs for portable devices.
Innovation Solution
A lens driving apparatus that includes a bobbin with a coil and magnet configuration, supported by elastic members and sensors, allowing for precise displacement detection and movement in multiple directions to address autofocus and handshake correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If VCM technology is adopted for conventional camera modules, then focusing function is achieved, but device size increases and power consumption rises
Solution Approach 1:
The patent extracts the magnet from the conventional VCM structure and places it on the stator, while the coil remains on the bobbin. This reconfiguration eliminates the need for a separate magnet holder and reduces overall device volume while maintaining the electromagnetic driving function for focusing.
Solution Approach 2:
The magnet on the stator serves dual purposes: it provides the magnetic field for the voice coil motor (focusing) and simultaneously enables handshake correction through interaction with the second coil. This multi-functionality reduces the number of components and decreases device size.
2Reliability
If handshake correction is incorporated into camera modules, then image stability improves, but device complexity increases
Solution Approach 1:
The patent merges the autofocus and handshake correction functions into a single integrated structure. The first coil and second coil share the same bobbin and magnetic field environment, allowing both focusing and shake correction without requiring separate motor assemblies, thus reducing structural complexity.
Solution Approach 2:
The magnetic field generated by the magnet on the stator is utilized for both autofocus (through the first coil) and handshake correction (through the second coil). This multi-functional use of the same magnetic field source simplifies the overall device structure while maintaining both functions.
3Measurement precision
If sensors are integrated directly on the bobbin, then displacement detection accuracy improves, but manufacturing difficulty increases
Solution Approach 1:
The sensor is pre-mounted on the bobbin before final assembly, allowing for precise positioning and calibration during the bobbin manufacturing process. This preliminary integration simplifies subsequent assembly steps and ensures accurate displacement detection without requiring complex post-assembly adjustments.
4Reliability
If elastic members are used for conductive connections, then reliability improves, but device complexity increases
Solution Approach 1:
The elastic members serve dual functions: they provide mechanical support and positioning for the bobbin while simultaneously serving as conductive pathways for electrical signals. This eliminates the need for separate support structures and conductive elements, reducing overall device complexity despite the enhanced reliability from the elastic connection.
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 enables accurate displacement sensing, power savings, miniaturization, and improved reliability by directly integrating sensors on the bobbin and using elastic members for conductive connections, effectively addressing the challenges of existing camera modules.
Implementation Method 1
a first sensor for detecting displacement of the bobbin in a first direction, a second magnet disposed to face the first sensor
Implementation Method 2
a second sensor for detecting displacement of the housing with respect to the base in the second and third directions
Implementation Method 3
a first coil being disposed at an outer circumferential surface of the bobbin, a first magnet disposed near the bobbin so as to face the first coil
Implementation Method 4
a second coil disposed so as to face the first magnet
Data Source
AI summary
A lens driving device according to an embodiment comprises: a bobbin wherein at least one lens is installed inside thereof and a first coil is installed on the outer circumferential surface thereof; a first magnet arranged around the bobbin so as to be opposite to the first coil; a housing for supporting the first magnet; upper and lower elastic members coupled with the bobbin and the housing; a first sensor for sensing displacement of the bobbin in the first direction; a second magnet arranged so as to be opposite to the first sensor; a base arranged to be spaced apart from the housing by a certain distance; a second coil arranged so as to be opposite to the first magnet; a circuit board whereon the second coil is installed; a plurality of support members for supporting the housing so as to be movable in the second and third directions which are orthogonal to the first direction with respect to the base and for connecting at least one of the upper and lower elastic members to the circuit board; and a second sensor for sensing displacement of the housing in the second or third direction with respect to the base.