Camera Actuator With Variable-Length Sub-Coils for Autofocus and Zoom
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Solution Overview
Problem
Existing camera devices face challenges in achieving ultra-slim, ultra-small, and high-resolution capabilities due to space constraints for image stabilization actuators, magnetic field interference, and limited lens movement for auto focusing and zooming functions.
Innovation Solution
A camera actuator design with a driving unit comprising a driving coil and magnet configuration that allows for increased lens movement and reduced size, including sub-coils of varying lengths along the optical axis to enhance auto focusing and zooming capabilities while minimizing magnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a common OIS actuator is disposed around the lens, then optical image stabilization function is achieved, but space for lens tilting or moving is insufficient and device size increases
Solution Approach 1:
The actuator is divided into multiple independent actuators, each responsible for specific movement directions. This segmentation allows for more efficient space utilization and reduces interference between components while maintaining OIS functionality.
Solution Approach 2:
The patent introduces movement along the optical axis direction in addition to lateral movements. By utilizing the optical axis dimension for lens movement, the design achieves OIS functionality without requiring excessive lateral space, thus resolving the space constraint contradiction.
2Illumination intensity
If lens size is increased to increase light reception, then image quality improves, but space occupied by OIS actuator limits further enlargement
Solution Approach 1:
By segmenting the actuator system into multiple smaller units positioned around the lens, the design reduces the space occupation of each individual actuator, thereby allowing larger lens aperture while maintaining OIS capability.
Solution Approach 2:
The actuator design enables both OIS function and lens positioning function using the same actuator components, maximizing space utilization and allowing larger lens size without proportionally increasing actuator space occupation.
3Volume of moving object
If OIS magnet and AF or zoom magnet are disposed close to each other, then device size is reduced, but magnetic field interference occurs
Solution Approach 1:
The patent extracts and separates the magnetic field sources into distinct groups with different polarities, positioning them such that their magnetic fields do not interfere with each other. This allows close spacing while eliminating harmful magnetic interference.
Solution Approach 2:
The actuator uses asymmetric magnetic pole arrangements where adjacent magnets have opposite polarities. This asymmetric configuration creates localized magnetic fields that cancel out interference effects, enabling compact design without magnetic interference.
4Measurement precision
If pixel density is increased for higher resolution, then camera resolution improves, but image shake becomes more severe in dark environment
Solution Approach 1:
The segmented actuator design enables more precise and responsive lens movement control, improving OIS effectiveness for high-resolution sensors that are more susceptible to shake in low-light conditions.
Solution Approach 2:
The actuator design allows for optimized movement parameters including larger moving distance and adjusted movement speed, enhancing the OIS performance to compensate for the increased sensitivity of high pixel density sensors to image shake.
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 design enables a camera actuator with improved moving distance for auto focusing and zooming, suitable for ultra-slim and high-resolution cameras, reducing weight and minimizing magnetic interference.
Implementation Method 1
a driving unit configured to move the first lens assembly and the second lens assembly, wherein the driving unit includes a driving coil, and a driving magnet facing the driving coil
Data Source
AI summary
An embodiment of the present invention provides a camera actuator comprising: a housing; a first lens assembly and a second lens assembly which are moved in an optical axis direction on the basis of the housing; and a driving unit which moves the first lens assembly and the second lens assembly, wherein the driving unit comprises: a driving coil; and a driving magnet facing the driving coil. The driving coil comprises: a first sub-coil; a second sub-coil; and a third sub-coil arranged between the first sub-coil and the second sub-coil, wherein the first sub-coil, the third sub-coil, and the second sub-coil are sequentially arranged along the optical axis, and the length of the third sub-coil in the optical axis direction is different from the length of at least one of the first sub-coil and the second sub-coil in the optical axis direction.