Asymmetric Magnet Camera Actuator Position Control
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Solution Overview
Problem
Small form factor cameras face challenges in achieving high image quality due to unwanted motion, which is difficult to compensate for with existing optical image stabilization and autofocus mechanisms, requiring accurate position measurement of camera components.
Innovation Solution
A camera unit with an asymmetric magnet arrangement and position sensor magnets, coupled with magnetic field sensors, allows for precise determination and adjustment of the optical package's position along the optical axis and orthogonal planes, enabling effective autofocus and optical image stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If small form factor cameras incorporate OIS and AF mechanisms, then image quality can be improved by compensating for unwanted motion, but device complexity increases due to additional components and control systems
Solution Approach 1:
The patent combines OIS and AF control systems into a unified architecture where a single processor manages both optical image stabilization and autofocus operations. The magnetic actuator system serves dual purposes: it can move the lens assembly for autofocus while simultaneously compensating for camera shake through OIS. This merging reduces overall system complexity compared to having separate independent control systems for each function.
Solution Approach 2:
The magnetic actuator and control system are designed to perform multiple functions: autofocus adjustment, optical image stabilization, and potentially other lens control operations. The position sensors and processing circuitry serve universal purposes across different operational modes, eliminating the need for dedicated separate systems for each function and thereby reducing overall device complexity.
2Measurement precision
If position sensors are added to achieve accurate lens position measurement, then measurement precision improves, but device complexity increases due to additional sensors and control circuitry
Solution Approach 1:
The magnetic field sensors serve dual purposes: they detect the position of the lens assembly for autofocus control and simultaneously provide position information for OIS operations. This universal sensor system eliminates the need for separate sensor systems for each function, achieving high measurement precision while minimizing the increase in device complexity through multi-functional utilization.
Solution Approach 2:
The patent implements closed-loop feedback control where position sensors continuously monitor lens assembly position and feed this information back to the processor. The processor then adjusts actuator signals to maintain precise positioning for both AF and OIS operations. This feedback mechanism enables high measurement precision to be effectively utilized across multiple functions without requiring proportionally complex control circuitry.
3Measurement precision
If magnetic field sensors are used to determine position of position sensor magnets, then position accuracy improves, but manufacturing precision requirements increase due to sensitive magnetic field measurements
Solution Approach 1:
The system incorporates self-calibration or self-adjustment mechanisms where the control processor analyzes magnetic field measurements and automatically compensates for manufacturing tolerances or misalignments. The feedback control system can detect and correct for positional variations in magnets and sensors during operation, reducing the stringency of manufacturing precision requirements while maintaining high measurement accuracy through active compensation.
Solution Approach 2:
The patent employs software-based parameter adjustment and calibration routines that modify operational parameters to compensate for manufacturing variations. By dynamically adjusting measurement and control parameters based on actual system performance, the system achieves high measurement precision without requiring extremely tight manufacturing tolerances for magnet and sensor placement.
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 position accuracy and reduces parasitic motion, leading to improved image quality by accurately compensating for unwanted camera motion and minimizing interference between adjacent camera units.
Implementation Method 1
one or more magnetic field sensors for determining a position of the moving member
Implementation Method 2
an asymmetric magnet arrangement for actuation along an optical axis and/or along a plane that is orthogonal to the optical axis
Data Source
AI summary
In some embodiments, a camera unit of a multifunction device may include an optical package and an actuator for moving the optical package. In some embodiments, the actuator may include an asymmetric magnet arrangement. The asymmetric magnet arrangement may include a lateral position control magnet situated at a first side of the optical package, and a pair of transverse position control magnets situated at respective second and third sides of the optical package opposite one another with respect to an axis between the optical package and the lateral magnet. In some embodiments, the actuator may include one or more position sensor magnets attached to the optical package, and one or more magnetic field sensors for determining a position of the position sensor magnets.