Camera Actuator Hall Sensor Layout for Zoom Position Detection
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Solution Overview
Problem
Conventional actuators for zoom lenses face challenges in accurately detecting the position of the carrier throughout the extended movement range, leading to deteriorated operation performance due to small errors in position detection, which is critical for precise implementation of autofocusing and zoom functions.
Innovation Solution
The actuator design incorporates a carrier with a magnet and a housing containing coils and hall sensors arranged to face the same magnetic pole, ensuring precise position detection and feedback control across the entire stroke range by optimizing the mutual positional relationship between the magnet, coil, and hall sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the moving distance of the zoom lens is extended to achieve zoom-in and zoom-out functions, then the driving force and stroke are improved, but the position detection precision deteriorates due to small errors accumulating over the extended range
Solution Approach 1:
The detection sensor is divided into multiple sensing elements arranged in an array along the optical axis direction. Each sensing element detects the magnetic field at a specific position, and the combined output provides precise position detection throughout the extended stroke range, eliminating error accumulation by distributing detection across multiple discrete sensing points
Solution Approach 2:
A magnet is introduced as an intermediary between the zoom lens and the detection sensor. The magnet generates a magnetic field that serves as a detectable signal carrier, allowing the detection sensor to accurately track the position of the carrier throughout the extended movement range without direct mechanical contact or complex sensing mechanisms
2Device complexity
If a generalized method of placing the hall sensor is used, then the device complexity is reduced, but the operation performance deteriorates due to inaccurate position detection throughout the extended movement range
Solution Approach 1:
The detection sensor is configured with multiple sensing elements positioned at specific locations along the optical axis, each optimized to detect the magnetic field at its local position. This localized optimization ensures accurate position detection at every point in the extended stroke range while maintaining a relatively simple overall structure
Solution Approach 2:
The positional relationship between the magnet and the detection sensor is carefully designed, with the sensor arranged to face the same magnetic pole when the carrier is at the reference position. This parameter optimization ensures that the magnetic field strength and direction are suitable for accurate detection throughout the entire movement range
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 configuration enhances driving efficiency and precision by providing clearer linearity in signal output from the hall sensors, enabling sophisticated feedback control and improved movement characteristics of the carrier throughout its extended movement section.
Implementation Method 1
a plurality of detection sensors configured to sense a position of the magnet
Implementation Method 2
a plurality of coils arranged along an optical axis to face the magnet
Data Source
AI summary
An actuator for a camera includes a carrier equipped with at least one lens and configured to move in an optical axis direction, a magnet provided in the carrier, a housing configured to accommodate the carrier, a plurality of coils arranged along an optical axis to face the magnet, and a plurality of detection sensors configured to sense a position of the magnet and disposed to be spaced apart from each other based on the optical axis direction. When the carrier is located at a reference position, the plurality of detection sensors all face the same one magnetic pole among magnetic poles of the magnet.