Camera Module Actuator Using Coil Inductance for Position Detection
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Solution Overview
Problem
Existing camera modules lack an efficient mechanism for auto-focusing and optical image stabilization, particularly in portable devices, which are prone to resolution degradation due to user hand-shake.
Innovation Solution
A camera module actuator that detects the position of a magnet using changes in resonant frequency, employing a coil, driver, and detector with a resonant frequency detecting circuit, eliminating the need for a hall sensor to provide precise positioning and movement of the lens barrel for auto-focusing and image stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a hall sensor is used to detect magnet position for auto-focusing and image stabilization, then positioning precision is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent extracts the magnet position detection function from the traditional hall sensor system and implements it through the existing coil's inductance changes. By detecting resonant frequency shifts caused by magnet movement, the system achieves positioning capability without requiring separate hall sensors, thereby reducing device complexity while maintaining measurement precision
Solution Approach 2:
The coil serves multiple functions: it acts as both the actuator component for generating magnetic force and as the sensing element for detecting magnet position through inductance changes. This multi-functionality eliminates the need for dedicated hall sensors, reducing both device complexity and manufacturing cost while maintaining precise position detection
2Measurement precision
If a hall sensor is used to detect magnet position, then positioning precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent removes the hall sensor component from the system and extracts the position detection capability from the coil's electromagnetic properties. By utilizing inductance changes and resonant frequency shifts, the system achieves accurate magnet position detection without requiring additional sensors, thereby reducing manufacturing cost while maintaining measurement precision
Solution Approach 2:
The patent replaces expensive hall sensors with a cost-effective approach using the existing coil structure. The coil's inherent electromagnetic properties are utilized for detection purposes, eliminating the need for costly additional components while achieving the required measurement precision for auto-focusing and image stabilization
3Measurement precision
If hall sensors are installed for precise magnet positioning, then auto-focusing and image stabilization performance is improved, but space efficiency decreases
Solution Approach 1:
The coil performs dual functions as both actuator and sensor, eliminating the need for separate hall sensor components. This integration reduces the overall space required for the actuator assembly while maintaining the precision needed for auto-focusing and optical image stabilization functions
Solution Approach 2:
The patent merges the actuator coil and position sensing functions into a single integrated system. By detecting position through inductance changes of the existing coil rather than using separate hall sensors, the design reduces component count and space occupation while achieving the required measurement precision
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
Enables precise detection of magnet position without a hall sensor, reducing manufacturing costs and improving space efficiency while effectively enabling auto-focusing and optical image stabilization, thereby enhancing image quality in portable devices.
Implementation Method 1
The inductance of the coil may vary based on a strength of a magnetic field of the magnet.
Implementation Method 2
a coil disposed to face the magnet; a driver configured to apply a driving signal to the coil to move the magnet; and a detector configured to detect a position of the magnet from a change in inductance of the coil
Implementation Method 3
The detector may include a resonant frequency detecting circuit including a capacitor, which forms a resonant tank together with the coil, and a resonant frequency of the resonant tank may be determined based on the inductance of the coil.
Data Source
AI summary
A camera module actuator is described including a magnet, a coil disposed to face the magnet, and a driver configured to apply a driving signal to the coil to move the magnet. The camera module actuator also includes a detector configured to detect a position of the magnet from a change in inductance of the coil, based on the movement of the magnet.