Lens Moving Structure for Low-Power AF and Handshake Correction
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Solution Overview
Problem
Conventional voice coil motor (VCM) technology is difficult to adopt in ultracompact camera modules due to high power consumption and the need for low power consumption, and there is a requirement for a technology that can incorporate optical image stabilizers to correct handshake in camera modules, especially in small-sized electronic devices like smartphones, while ensuring durability and accurate, rapid movement of the optical system.
Innovation Solution
A lens moving apparatus with a bobbin, first and second coils, magnets, elastic members, and support members that allow for accurate and rapid handshake correction and autofocusing, featuring a simplified structure and reduced driving force, utilizing electromagnetic interactions and elastic support to move the optical module in multiple directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If VCM technology is used in conventional camera modules, then focusing function is achieved, but power consumption is high and it cannot be adopted in ultracompact camera modules
Solution Approach 1:
The patent replaces the conventional VCM electromagnetic driving system with a piezoelectric actuator that utilizes piezoelectric effect for mechanical displacement. This substitution eliminates the need for continuous electromagnetic power consumption while achieving the same focusing function through voltage-driven piezoelectric material expansion/contraction, thereby reducing power consumption and enabling ultracompact camera module integration
2Reliability
If optical image stabilizer is incorporated to correct handshake, then image stability is improved, but device size increases and durability is compromised
Solution Approach 1:
The patent merges the optical image stabilizer (OIS) and auto-focus (AF) functions into a single integrated lens moving apparatus. The same piezoelectric actuator and support member structure serve dual purposes: correcting handshake movements and adjusting focus, thereby eliminating the need for separate OIS and AF mechanisms, reducing overall device size, and improving durability through simplified structure
Solution Approach 2:
The support members and piezoelectric actuators are designed to perform multiple functions simultaneously - they enable both lateral movement for handshake correction and axial movement for focus adjustment. This multi-functionality reduces the number of components needed, thereby decreasing device complexity and size while maintaining image stability
3Force
If conventional VCM technology is used, then focusing is achieved, but driving force is excessive for compact designs
Solution Approach 1:
The patent changes the driving mechanism from high-force electromagnetic VCM to low-force piezoelectric actuation. The piezoelectric material generates precise, controlled displacement through voltage application, providing just enough force for focusing and stabilization without the excessive driving force of VCM, thereby enabling more compact structural design
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 reduced driving force and increased durability for handshake correction, enabling accurate and rapid movement of the optical system in compact camera modules, addressing the challenges of power consumption and durability in small-sized electronic devices.
Implementation Method 1
a first coil, a first magnet disposed to face the first coil
Implementation Method 2
a second coil disposed to face the first magnet
Implementation Method 3
upper and lower elastic members each coupled to both the bobbin and the housing
Data Source
AI summary
A lens moving apparatus includes a bobbin including a first coil disposed therearound, a first magnet disposed to face the first coil, a housing for supporting the first magnet, upper and lower elastic members each coupled to both the bobbin and the housing, a base disposed to be spaced apart from the housing by a predetermined distance, a second coil disposed to face the first magnet, a printed circuit board on which the second coil is mounted, a plurality of support members, which support the housing such that the housing is movable in second and/or third directions and which connect at least one of the upper and lower elastic members to the printed circuit board, and a conductive member for conductively connecting the upper and lower elastic members.