Dual-Stage Lens Motion for Low-Power Image Stabilization
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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 existing handshake correction technologies require high driving force and lack durability, especially in compact camera modules prone to shocks and hand tremors.
Innovation Solution
A lens moving apparatus with a simplified structure that reduces driving force and increases durability, incorporating a first lens moving unit for autofocusing and a second lens moving unit for handshake correction, using magnets and coils for precise movement in x and y axes, with elastic members for support and a sensor for feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional voice coil motor (VCM) technology is adopted for handshake correction, then image stabilization can be achieved, but power consumption increases and durability decreases
Solution Approach 1:
The lens moving apparatus is divided into two independent units: a first lens moving unit for autofocusing and a second lens moving unit for handshake correction. This segmentation allows each unit to be optimized for its specific function, enabling the handshake correction unit to use a simpler, lower-power mechanism while the autofocus unit handles precision focusing, thereby reducing overall power consumption and improving durability.
Solution Approach 2:
The first lens moving unit serves dual purposes: it performs autofocusing during normal operation and can be selectively deactivated during handshake correction. This multi-functionality allows the system to use the more durable first unit for focusing while relying on the specialized second unit for stabilization, reducing wear on the autofocus mechanism and extending overall system durability.
2Speed
If high driving force is used for handshake correction, then rapid and accurate image stabilization can be achieved, but durability of the lens moving apparatus decreases
Solution Approach 1:
By separating autofocus and handshake correction into distinct units, the second unit can be designed specifically for rapid stabilization movements without the mechanical constraints of the autofocus unit. This allows optimized speed for handshake correction while isolating the high-force movements from the autofocus mechanism, preserving its durability.
3Device complexity
If a simplified structure is used for the lens moving apparatus, then manufacturing cost and complexity are reduced, but precision and speed of handshake correction may be compromised
Solution Approach 1:
The simplified structure is achieved by dividing functionality into two units, where the second unit uses a straightforward electromagnetic driving mechanism without complex mechanical linkages. This segmentation allows the precision requirements to be met through controlled electromagnetic actuation rather than complex mechanical systems, maintaining accuracy while reducing overall structural complexity.
Solution Approach 2:
The apparatus incorporates a sensor that detects the position of the lens barrel and provides feedback to the control unit. This feedback mechanism enables precise control of the second lens moving unit's movements, ensuring accurate handshake correction despite the simplified structure. The real-time position monitoring compensates for the lack of complex mechanical precision elements.
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
Enables accurate and rapid handshake correction with reduced power consumption, enhancing the durability and performance of compact camera modules in mobile devices.
Implementation Method 1
a coil wound around the bobbin and a magnet disposed to correspond to the coil, and configured to move the lens barrel in the optical axis direction by the interaction between the magnet and the coil
Implementation Method 2
an elastic member coupled to the bobbin and the housing, and configured to support the bobbin
Data Source
Figure 1
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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.