Magnetic Shield Caps for VCM Modules in Camera Arrays
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Solution Overview
Problem
The manufacturing of digital camera modules is hindered by the strong magnetic fields generated by voice coil motor (VCM) modules, which cause repelling forces that lead to inconsistent spacing and increased costs due to the need for larger silicon wafer spacing and inefficient use of silicon, as well as additional costly singulation processes that can degrade image quality.
Innovation Solution
The use of magnetic shields made from high magnetic permeability metal alloys is introduced to reduce the magnetic field around VCM modules, allowing for closer spacing of camera modules during manufacturing and increasing the number of modules that can be assembled on a substrate without sacrificing image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If larger spacing between image sensors is used to minimize repelling force between VCM modules, then magnetic interference is reduced, but silicon usage efficiency decreases and manufacturing cost increases
Solution Approach 1:
A magnetic shield cap is introduced as an intermediary component between adjacent VCM modules. This cap contains the magnetic flux generated by permanent magnets within each VCM module, preventing magnetic interference from affecting adjacent modules. As a result, image sensors can be placed closer together on the silicon wafer without suffering from magnetic repulsion effects, thereby improving silicon usage efficiency while maintaining low magnetic interference
Solution Approach 2:
The harmful magnetic flux is extracted and contained within a localized region by the magnetic shield cap. The cap acts as a magnetic flux containment structure that prevents the magnetic field from extending beyond the immediate vicinity of each VCM module, effectively isolating the magnetic interference to a small area and allowing closer spacing of adjacent modules
2Object-affected harmful factors
If singulation method is used to attach image sensors with greater spacing, then magnetic interference is reduced, but manufacturing cost increases and image quality may degrade due to particulate debris
Solution Approach 1:
The magnetic shield cap is attached to each VCM module in advance, before the modules are mounted onto the image sensors on the silicon wafer. This preliminary action ensures that magnetic flux containment is already in place during the array manufacturing process, allowing all modules to be processed together without requiring subsequent singulation operations. This eliminates the need for additional manufacturing steps while maintaining effective magnetic shielding
Solution Approach 2:
Multiple VCM modules with their respective magnetic shield caps are processed together as an array on the silicon wafer. By combining the magnetic shielding function with the VCM module assembly and processing them in parallel during mounting, the manufacturing process avoids the need for separate singulation operations, reducing both cost and complexity while preventing particulate contamination
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 magnetic shields significantly reduce the repelling force between adjacent VCM modules, enabling a 50% increase in camera module density on a substrate, improving manufacturing throughput and reducing costs while maintaining image quality.
Implementation Method 1
The magnetic shields significantly reduce the repelling force between adjacent VCM modules
Implementation Method 2
magnetic shields made from high magnetic permeability metal alloys
Data Source
AI summary
A method for manufacturing camera modules for use in portable electronic devices, such as mobile phones, is provided. More specifically, in camera modules utilizing lens motion type auto focus actuation, permanent magnets associated with voice coil motors utilized in the auto focus system, generate magnetic flux that can interfere with the process of bonding image sensors to camera modules if the permanent magnets of different voice coil motors are positioned too closely. Incorporating a magnetic shield into the manufacturing process to restrain or control the magnetic flux generated by the permanent magnets permits voice coil motors camera modules to be positioned closer together during the manufacturing process. This increases manufacturing throughput and reduces cost.