Camera Actuator Coil Detects Displacement via Inductance
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Solution Overview
Problem
Existing camera module actuators face challenges in accurately detecting displacement for autofocusing and optical image stabilization, particularly in efficiently utilizing driving signals to generate oscillation signals for precise position detection without the need for separate Hall sensors, which can increase manufacturing costs and reduce space efficiency.
Innovation Solution
The actuator incorporates a driving coil with a processor that generates a driving signal and provides a gate control signal to transistors, detecting displacement based on oscillation signals generated by the driving coil's inductance and parasitic capacitance, allowing for precise position detection without a separate Hall sensor, thereby reducing costs and improving space efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate Hall sensor is used for displacement detection, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the displacement detection function into the existing driving coil by utilizing its inductance characteristics. The driving coil serves dual purposes: generating electromagnetic force for actuation and sensing displacement through inductance changes, thereby eliminating the need for separate Hall sensors and reducing overall device complexity while maintaining measurement precision.
Solution Approach 2:
The driving coil is designed to perform multiple functions: it acts as both an actuator (generating electromagnetic force to move the lens) and a sensor (detecting displacement through inductance variations). This multi-functionality reduces the number of components needed and simplifies the overall sensor system while achieving accurate displacement detection.
2Measurement precision
If a separate Hall sensor is used for displacement detection, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines the sensing function with the existing driving coil, eliminating the need for additional Hall sensors. This reduces the number of components that need to be manufactured and assembled, thereby lowering manufacturing costs while maintaining displacement detection precision through the coil's inductance characteristics.
Solution Approach 2:
The driving coil serves itself by utilizing its own inductance properties for displacement sensing. This self-service approach eliminates the need for external sensing components, reducing both manufacturing complexity and cost while achieving accurate position detection.
3Measurement precision
If a separate Hall sensor is used for displacement detection, then measurement precision is improved, but space efficiency decreases
Solution Approach 1:
The patent merges the sensing function into the existing driving coil structure, eliminating the need for separate Hall sensor components and their associated mounting spaces. This integration maintains displacement detection precision while significantly improving space efficiency within the camera module.
Solution Approach 2:
The driving coil performs both actuation and sensing functions, eliminating the need for dedicated sensor space. This multi-functionality allows the same component to serve dual purposes, thereby improving space efficiency while maintaining accurate displacement detection capabilities.
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 enables precise detection of displacement for both autofocusing and optical image stabilization, reducing manufacturing costs and improving space efficiency by eliminating the need for separate Hall sensors while maintaining accurate position detection.
Implementation Method 1
an oscillation signal generated in a driving signal applied to the driving coil
Implementation Method 2
a driving coil disposed to face a detection target... provide a driving force to the lens barrel
Data Source
AI summary
An actuator of a camera module includes a driving coil disposed to face a detection target; a driving circuit including a plurality of transistors connected to the driving coil; and a processor configured to provide a respective gate control signal to a gate of each of the plurality of transistors, and detect a displacement of the detection target based on a component of an oscillation signal generated in a driving signal applied to the driving coil in response to an operation of any one of the plurality of transistors being switched by the respective gate control signal.