Stacked Body Dummy Pattern for Voice Coil Motor Magnetic Field
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Solution Overview
Problem
Voice coil motors exhibit poor responsiveness due to inadequate electromagnetic force, which affects the performance of devices that rely on them, such as camera shake correction systems.
Innovation Solution
A stacked body configuration incorporating insulating base material layers with a winding-shaped conductive coil and electrically isolated dummy patterns that enhance the magnetic field intensity by acting as a magnetic field shield, increasing the electromagnetic force and responsiveness of the voice coil motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the voice coil motor uses a conventional coil structure without dummy patterns, then the device complexity is low, but the electromagnetic force is insufficient resulting in poor responsiveness
Solution Approach 1:
The patent divides the conductive pattern into two distinct segments: the functional coil pattern and the dummy pattern. The coil pattern generates the magnetic field for actuation, while the dummy pattern acts as a magnetic shield. This segmentation allows the system to achieve both sufficient electromagnetic force and improved responsiveness without excessive complexity, as each segment performs a specific function.
Solution Approach 2:
The dummy pattern serves as an intermediary element between the coil and the external environment. It acts as a magnetic field shield that confines and intensifies the magnetic field in the desired region while preventing field leakage. This intermediary structure enhances the electromagnetic force efficiency and responsiveness without requiring a complete redesign of the coil itself.
2Reliability
If dummy patterns are added to increase magnetic field intensity, then the electromagnetic force and responsiveness improve, but the manufacturing process becomes more complex
Solution Approach 1:
The patent merges the coil pattern and dummy pattern into a single integrated conductive structure formed on the same substrate. Both patterns are created using the same manufacturing processes (printing, sintering, or electroplating), eliminating the need for separate fabrication steps. This merging approach maintains manufacturing simplicity while achieving the reliability and responsiveness improvements through the dummy pattern's magnetic shielding effect.
3Force
If the stacked body has a step structure with varying thickness, then the magnetic field intensity around the step portion increases, but the shape stability of the stacked body deteriorates
Solution Approach 1:
The dummy pattern is strategically positioned to provide preliminary magnetic shielding at the step portion where the stacked body thickness varies. By placing the dummy pattern adjacent to the step, it preemptively counteracts the magnetic field leakage that would occur at this geometric discontinuity. This preliminary anti-action maintains both the enhanced magnetic field intensity in the operational region and the overall shape stability of the stacked body.
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 introduction of dummy patterns between the coil and the step in the stacked body structure significantly increases the magnetic field intensity above the coil, enhancing the electromagnetic force and responsiveness of the voice coil motor, thereby improving the performance of devices like camera shake correction systems.
Implementation Method 1
the dummy pattern increases the intensity around the step portion, thus preventing a loss of the shape of the stacked body
Implementation Method 2
a voice coil motor is an actuator that utilizes a change in a magnetic field caused by a change in a current flowing through a coil
Data Source
AI summary
A stacked body includes a base including a plurality of insulating base material layers, a coil including a winding-shaped conductive pattern located on at least one of the plurality of the insulating base material layers, and an electrically isolated dummy pattern extending along at least a portion of the coil outside of the coil on at least one of the plurality of the insulating base material layers in a plan view, wherein the stacked body includes a step at which a thickness of the stacked body is different in a stacking direction, and the dummy pattern is located between the coil and the step at a portion defining the step where the thickness of the stacked body is larger.