Dual-Sided Coil Substrate Layout for Compact Image Stabilization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional camera modules with coil patterns on circuit boards suffer from reliability issues due to short circuits in bent regions, and there is a need for a coil substrate that maximizes Lorentz force generation in a limited space while improving manufacturing efficiency and reducing resistance.
Innovation Solution
A coil substrate design with first and second coil pattern portions on opposite surfaces of an insulating layer, connected by pad portions and vias, allowing for uniform plating and increased line widths in critical regions, and a camera module incorporating this substrate for improved hand shake prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coil pattern is disposed on a circuit board with bent regions, then the coil pattern can be formed, but the photosensitive pattern collapses during the bending process causing short circuits between coil electrodes
Solution Approach 1:
The coil pattern is formed on both the front surface and back surface of the circuit board, utilizing the third dimension (depth/layer) to distribute the coil structure. This spatial distribution prevents pattern collapse in bent regions by avoiding concentration of photosensitive materials in single-layer bent areas, thereby preventing short circuits between coil electrodes.
Solution Approach 2:
The coil pattern is divided into multiple segments located at different positions on the circuit board (front surface and back surface). This segmentation distributes the electrical pathways, so that if one region experiences bending stress, other segments remain intact and functional, preventing complete short circuit failure.
2Volume of moving object
If the coil pattern is formed in a limited space, then the camera module size is reduced, but the Lorentz force generation is insufficient
Solution Approach 1:
The coil pattern extends into the third dimension by utilizing both front and back surfaces of the circuit board. This effectively doubles the available space for coil winding within the same footprint, increasing the total wire length and turn count, thereby enhancing Lorentz force generation without increasing the camera module's external dimensions.
Solution Approach 2:
The coil pattern on the back surface is positioned to overlap or align with the front surface coil pattern when viewed from above, creating a nested configuration. This nesting maximizes the use of available space, allowing the magnetic field lines to pass through both coil layers, thereby amplifying the Lorentz force effect within a compact volume.
3Ease of manufacture
If the coil pattern uses standard plating thickness, then the manufacturing process is simple, but the resistance is high
Solution Approach 1:
The plating thickness is increased specifically in the bent regions of the coil pattern where stress concentration occurs during bending. This localized thickening compensates for potential material thinning or damage in high-stress areas, maintaining low electrical resistance and high reliability without requiring uniform thick plating across the entire circuit board, thus preserving manufacturing efficiency.
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 design enhances Lorentz force generation, improves manufacturing process efficiency, reduces resistance, and increases reliability by minimizing short circuits and maintaining positional balance, thereby enhancing the camera module's hand shake prevention capabilities.
Implementation Method 1
maximizing a Lorentz force generated in the coil substrate
Data Source
AI summary
A coil substrate according to an embodiment includes an insulating layer; a first coil pattern portion disposed on one surface of the insulating layer; a second coil pattern portion disposed on the other surface of the insulating layer; and a pad portion disposed on the one surface of the insulating layer and connected to the first coil pattern portion, wherein the first coil pattern portion includes: an inner coil pattern portion; and an outer coil pattern portion spaced apart from the inner coil pattern portion at a predetermined interval and disposed outside the inner coil pattern portion, wherein the pad portion is disposed between the inner coil pattern portion and the outer coil pattern portion.