CML's SMA technology solves a major problem with magnetic interference inside premium smartphones

Premium smartphones are continuing to feature an increasing number OIS and AF enabled cameras per device, and in turn this is causing an ever-growing challenge for smartphone OEMs who need to take into account magnetic interference of OIS and AF camera modules.

Robin Eddington, Actuator Design Group Manager at CML, explains below.

A typical VCM-based OIS camera system might use 4 neodymium rare-earth magnets per actuator. The actuator manufacturer can carefully design the actuator to ensure no unexpected magnetic interference within the camera module, but with multiple actuators per handset, the smartphone manufacturer must also take into account how each camera module will affect each other, which often means having to position them differently, leaving gaps between camera modules or other critical components such as the vibration motors or speakers. The magnetic interaction between separate components can be difficult to simulate,  and with time to market pressures, it ultimately leads to compromises with the design.

The recent trend of foldable handsets has conflated the problem further, as often the latch mechanism which keeps the handset shut uses much more powerful magnets than those found in the camera module. Magnets also cause trouble for the designers of smartphone accessories such as cases. Apple provide guidelines recommending that accessory designers avoid the use of magnets and metal components to avoid interference with the AF and OIS operation.

Magnets are inherent to the operation of a VCM actuator, and thus cannot be avoided. Cambridge Mechatronics’ Shape Memory Alloy (SMA) actuators do not use magnets and therefore give much more flexibility in the design process. Smartphone OEMs can position CML-enabled camera modules where they like without fear of interfering with other components or accessories which do contain magnets.

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