Camera Module Actuator Position Detection via Dual-Frequency Inductance
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Solution Overview
Problem
Camera module actuators face challenges in precisely detecting the position of a magnet without using a hall sensor, which affects autofocusing and optical image stabilization performance.
Innovation Solution
The actuator employs a position detecting unit with at least two sensing coils forming oscillation circuits that generate signals with different frequency ranges to detect the position of a magnet, enabling precise position detection without a hall sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a hall sensor is used to detect magnet position, then detection accuracy is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the position detection function from a separate hall sensor and integrates it into the existing sensing coil system. The sensing coil serves dual purposes: generating driving force for the magnet and detecting position through inductance changes, thereby eliminating the need for a dedicated hall sensor and reducing device complexity
Solution Approach 2:
The sensing coil is designed to perform multiple functions: it generates electromagnetic driving force for magnet actuation and simultaneously detects magnet position through inductance variations. This multi-functionality reduces the number of components needed while maintaining detection accuracy
2Measurement precision
If a hall sensor is used to detect magnet position, then detection accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent removes the hall sensor component from the bill of materials and replaces it with the existing sensing coil system, directly reducing manufacturing costs while maintaining position detection capability through inductance-based detection
Solution Approach 2:
The patent uses the existing sensing coil infrastructure, which is already part of the actuator system, rather than adding expensive hall sensors. This leverages existing components to achieve the detection function at lower cost
3Measurement precision
If a hall sensor is used to detect magnet position, then detection accuracy is improved, but space efficiency decreases
Solution Approach 1:
The patent eliminates the hall sensor component and its associated mounting space, using instead the inductance detection method through the sensing coil which shares the same spatial footprint, thereby improving space efficiency
Solution Approach 2:
The patent merges the position detection function with the existing sensing coil structure, eliminating the need for separate hall sensor mounting space. The detection function is combined with the driving coil assembly, reducing overall actuator space occupation
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 allows for accurate detection of the lens barrel position, enhancing autofocusing and optical image stabilization, while reducing manufacturing costs and improving space efficiency by eliminating the need for a hall sensor.
Implementation Method 1
a position detecting unit disposed to face the detection target and including at least two sensing coils respectively forming at least two oscillation circuits
Data Source
AI summary
An actuator of a camera module includes: a detection target; and a position detecting unit disposed to face the detection target and including at least two sensing coils respectively forming at least two oscillation circuits, wherein the position detecting unit detects a position of the detection target depending on at least two oscillation signals generated by the at least two oscillation circuits and having different frequency ranges.