Polymer Actuator Lens Drive for Compact Camera OIS
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Solution Overview
Problem
Existing voice coil motor (VCM) technology is difficult to apply to subminiature, low-power camera modules, and there is a need for improved autofocus and optical image stabilization (OIS) performance in miniaturized camera modules to address increased resolution and functionality demands.
Innovation Solution
A lens moving apparatus using a polymer actuator that reduces height in the optical-axis direction and performs OIS operations, incorporating a circuit board, bobbin, magnet, coil, and elastic members to inhibit drooping and magnetic interference, with electrodes and drive signals to control movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If voice coil motor (VCM) technology is applied to camera modules, then autofocus and optical image stabilization functions are achieved, but the device size and power consumption increase, making it unsuitable for subminiature camera modules
Solution Approach 1:
The patent replaces the traditional voice coil motor (electromagnetic system) with a polymer actuator system that uses electroactive polymer materials. This substitution enables the same autofocus and optical image stabilization functions to be achieved with a significantly reduced device volume and lower power consumption, making it suitable for subminiature camera modules while maintaining the required adaptability and versatility
Solution Approach 2:
The patent changes the fundamental operating parameters of the actuator system by transitioning from electromagnetic actuation (VCM) to electroactive polymer actuation. This parameter change involves using voltage-driven polymer deformation instead of current-driven electromagnetic force, resulting in reduced size and power consumption while preserving the essential autofocus and OIS functionalities
2Volume of moving object
If camera modules are miniaturized to meet demand for smaller devices, then device size is reduced, but autofocus and optical image stabilization performance deteriorates
Solution Approach 1:
The patent employs polymer actuators with electroactive polymer materials that provide high force density and precise control, enabling reliable autofocus and optical image stabilization performance even in miniaturized camera modules. This mechanical substitution maintains functional reliability while achieving the required size reduction
Solution Approach 2:
The patent utilizes composite polymer actuator structures combining electroactive polymer materials with supportive frameworks and electrode systems. These composite materials enable the actuator to deliver sufficient force and precision for reliable autofocus and OIS operation in compact form factors, preventing performance deterioration despite miniaturization
3Length of stationary object
If polymer actuators are used for OIS operation, then device height in optical-axis direction is reduced, but susceptibility to magnetic field interference increases
Solution Approach 1:
The patent replaces electromagnetic actuation systems with polymer actuator systems that operate on electroactive polymer principles, fundamentally eliminating susceptibility to magnetic field interference. This substitution reduces the device height in the optical-axis direction while making the system immune to magnetic interference, as polymer actuators respond to voltage rather than magnetic fields
Solution Approach 2:
The patent converts the potential vulnerability of polymer actuators to electrical interference into an advantage by designing electrode configurations and drive circuits that are immune to magnetic field interference. The electroactive polymer mechanism, which responds to voltage rather than magnetic fields, naturally provides protection against magnetic interference while achieving reduced device height
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
The solution enables reduced height and improved autofocus and OIS performance, inhibiting drooping and magnetic interference, and supports larger, heavier lenses, enhancing camera module functionality.
Implementation Method 1
a coil disposed on the bobbin and configured to move the bobbin in an optical-axis direction by interaction with the magnet
Implementation Method 2
the polymer actuator is bending-deformed in a direction toward the second electrode from the first electrode or in a direction toward the first electrode from the second electrode by the first drive signal
Implementation Method 3
a polymer actuator comprising one end coupled to the upper elastic member, wherein the circuit board is conductively connected to the polymer actuator and configured to supply a first drive signal to the polymer actuator
Data Source
AI summary
An embodiment comprises: a circuit board; a housing disposed on the circuit board; a bobbin disposed within the housing; a magnet disposed in the housing; a coil disposed on the bobbin to move the bobbin in an optical-axis direction by interaction with the magnet; an upper elastic member coupled to the bobbin and the housing; and a polymer actuator coupled at one end thereof to the upper elastic member, wherein the circuit board is electrically connected to the polymer actuator to supply a first driving signal to the polymer actuator, and the polymer actuator moves the housing in a direction perpendicular to the optical-axis direction by the first driving signal.