Camera Module EMI Shielding via Voice-Coil Motor Grounding
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Solution Overview
Problem
Digital camera modules face interference from electro-magnetic waves generated by voice-coil motors, which can affect the proper functioning of other electronic components.
Innovation Solution
The camera module incorporates a grounding structure that electrically connects the metallic casing of the voice-coil motor to the circuit board, providing effective EMI shielding by grounding the metallic casing, thereby preventing external electro-magnetic waves from interfering with electrical signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a voice-coil motor is used for driving lens modules, then automatic focus function is achieved, but electro-magnetic waves are generated that interfere with other electronic components
Solution Approach 1:
A grounding structure is introduced as an intermediary element between the voice-coil motor and the circuit board. This grounding structure provides a dedicated path for electro-magnetic interference to be discharged to ground, preventing it from affecting other electronic components. The grounding structure includes a grounding pad on the circuit board and a grounding electrode that connects to the voice-coil motor, creating an intermediate channel for EMI dissipation.
Solution Approach 2:
The harmful electro-magnetic interference is extracted and separated from the main circuit by providing a dedicated grounding path. The grounding structure extracts the EMI from the voice-coil motor and directs it to ground, isolating it from other electronic components. This extraction approach removes the harmful effect while preserving the useful automatic focus function.
2Object-affected harmful factors
If EMI shielding is enhanced by grounding the metallic casing, then interference with electronic components is reduced, but device complexity increases
Solution Approach 1:
The grounding structure is designed to serve multiple functions simultaneously. The grounding pad on the circuit board not only provides EMI discharge path but also serves as a mounting reference for the grounding electrode. The metallic casing of the voice-coil motor serves both as structural protection and as part of the EMI shielding system when connected to the grounding electrode. This multi-functionality reduces the need for separate dedicated components.
Solution Approach 2:
The grounding structure merges several elements into an integrated system: the circuit board's grounding pad, the grounding electrode, and the metallic casing are combined into a unified grounding path. Rather than adding separate shielding components, the design merges the existing structural elements with the grounding function, reducing overall complexity while maintaining EMI protection effectiveness.
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 effectively shields the camera module from external EMI, ensuring reliable operation of electronic components by grounding the metallic casing of the voice-coil motor, reducing electromagnetic interference.
Implementation Method 1
The camera module incorporates a grounding structure that electrically connects the metallic casing of the voice-coil motor to the circuit board, providing effective EMI shielding by grounding the metallic casing
Data Source
AI summary
A camera module includes a circuit board of a grounding pad, a lens module, and a voice-coil motor. The voice-coil motor for receiving and driving the lens module automatically focus comprises a main body, a metallic casing and a grounding structure. The metallic casing covers the main body. After electrically grounding by connecting with the grounding pad of the circuit board, the grounding structure connects with the metallic casing and the circuit board. With the grounding structure, the metallic casing can be grounded. Thereby, prevent external electro-magnetic waves from affecting electrical signals communicated between the camera module and the circuit board.