Optical Image Stabilization Camera Module with SMA Wire Actuation
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Solution Overview
Problem
The existing camera modules face challenges in achieving effective image stabilization due to the limitations in driving force provided by the motor, which affects the image stabilization stroke and response speed, especially as the lens size and weight increase.
Innovation Solution
The optical image stabilization camera module incorporates a second driving part with interlaced SMA wires to drive the photosensitive chip, allowing for simultaneous movement of the lens and photosensitive chip in opposite directions, thereby improving image stabilization stroke and response speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the lens size and weight are increased to improve imaging quality, then the imaging quality is improved, but the driving force requirements increase and the motor cannot provide sufficient driving force
Solution Approach 1:
The camera module is divided into two separate driving systems: a first driving part (motor) for driving the lens, and a second driving part (SMA wires) for driving the photosensitive chip. This segmentation allows each driving mechanism to be optimized independently, with the SMA wires providing additional stabilization capability without burdening the motor with excessive weight compensation requirements.
Solution Approach 2:
The photosensitive chip acts as an intermediary compensation element. Instead of requiring the motor to directly compensate for all shake effects on a heavy lens, the system uses the photosensitive chip as a mediator that can be rapidly positioned to counterbalance image displacement, thereby reducing the direct driving force requirements on the motor-lens system.
2Force
If the motor driving force is increased to handle heavier lenses, then the driving force is sufficient, but the volume of the camera module increases
Solution Approach 1:
The patent replaces part of the traditional mechanical motor-driven stabilization system with an intelligent control system using SMA (shape memory alloy) wires. The SMA wires can be controlled to contract and extend, providing precise positioning of the photosensitive chip with smaller actuation forces compared to driving a heavy lens, thereby reducing the overall volume requirements.
Solution Approach 2:
Instead of moving the heavy lens to compensate for shake (traditional approach), the patent inverts the approach by moving the lighter photosensitive chip in the opposite direction to achieve the same image stabilization effect. This inversion significantly reduces the mass that needs to be accelerated, allowing for a more compact motor design.
3Volume of moving object
If the motor is made more compact to reduce volume, then the volume is reduced, but the driving force and response speed decrease
Solution Approach 1:
The patent introduces dynamic control through the SMA wire system, which can rapidly adjust the position of the photosensitive chip in response to detected shake. The SMA wires provide a dynamic compensation mechanism that operates independently of the motor's mechanical limitations, enabling fast response speeds within a compact form factor.
Solution Approach 2:
The system uses a gyroscope to detect shake in advance and issues instructions to the SMA wires to pre-position the photosensitive chip for compensation. This preliminary detection and action allow the compact system to respond faster than a purely reactive motor-driven system would allow.
4Reliability
If the lens is driven to move in multiple degrees of freedom to compensate for all types of shake, then the image stabilization ability is improved, but the motor structure becomes more complicated
Solution Approach 1:
The stabilization function is segmented between two independent systems: the motor-driven lens positioning system and the SMA wire-driven photosensitive chip positioning system. Each system handles specific aspects of stabilization, dividing the complex multi-degree-of-freedom control task into simpler, independent subsystems with dedicated functions.
Solution Approach 2:
The photosensitive chip serving platform is designed as a multi-functional component that can accommodate different lens types and configurations while providing consistent stabilization capability. The SMA wire arrangement with fixed ends at corner areas allows the same basic structure to handle various shake patterns without requiring complex reconfiguration.
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 compensate for larger camera shakes and improves response speed, while maintaining a compact structure suitable for miniaturized camera modules.
Implementation Method 1
each side surface is provided with two interlaced SMA wires, and two ends of each SMA wire are connected to a fixed end of the second basic portion and a fixed end of the second movable portion, respectively
Data Source
AI summary
The present application relates to an optical image stabilization camera module, comprising: a lens; a photosensitive assembly having a photosensitive chip; a first driving part adapted to drive the lens to translate in x-axis and y-axis directions; and a second driving part comprising a second basic portion and a second movable portion, the second driving part having four side surfaces, wherein each side surface is provided with two interlaced SMA wires, and both ends of each SMA line are connected to a fixed end of the second basic portion and a fixed end of the second movable portion, respectively; each of the fixed ends is located at a corner area of the second basic portion or the second movable portion. The photosensitive assembly is fixed to the second movable portion, and the second movable portion is adapted to drive, under the drive of the SMA lines, the photosensitive chip to move in an xoy plane; and the lens and the photosensitive chip are configured to be simultaneously driven and move in opposite directions. According to the present application, the image stabilization stroke and the image stabilization response speed of the camera module can be improved at the cost of a small volume.