Optical image stabilization: comparison of MEMS and non-MEMS technologies

MEMS Drive is a fabless MEMS based actuator device maker focusing on optical image stabilization (OIS) technology for mobile devices.  The company raised $11 million in its series B round in October 2016, and is aiming to replace the currently dominant voice coil motor (VCM) technology with its MEMS based chip.  The company is planning to use the funds from the most recent financing round to expand capacity and team, and to further customize their actuator to fit a wider variety of image sensors and customer requirements.  MEMS Drive is already working with OPPO, a Chinese smartphone maker, which announced an image stabilization feature based MEMS Drive’s technology at the Mobile World Congress in 2016.  We recently spoke with the company’s CEO Colin Kwan about the technology trends in this market segment, competitive dynamics, and application requirements.

MEMS Journal: What is your main product and which problem does it solve?

Colin Kwan: Our current product is a MEMS based actuator sitting underneath the image sensor.  We move the image sensor in x-y plane in a very fast and precise way.  This allows us to compensate the undesired vibrations that cause image blur while taking a photo.  Currently available technologies only provide 2-axis compensation, whereas we provide 3-axis compensation.

MEMS Journal: Who are your main competitors?  How do your competitor’s technologies compare to MEMS Drive?

Colin Kwan: We don’t currently see any technologies on the market that can provide 3-axis compensation OIS solution for mobile phone.  VCM is considered as our competing technology.  Currently OIS actuator in mobile phone are dominated by voice coil motor (VCM) suppliers in Japan, namely TDK, Mitsumi and Alps.  These companies take up more than 90% of mobile phone OIS market.

MEMS Journal: Could you please discuss the history of VCM a bit more and, more specifically, its use in compact camera modules (CCMs)?

Colin Kwan: VCM has been used in mobile phone CCM such as auto focus for approximately 10 years and then for OIS applications in last two years.  Currently, mobile phone OEMs are more comfortable with the supply chain and expectation of performance that have been set to date.  Voice coil motor performing auto focus, or VCM AF, which moves the lens barrel in the z-direction is a very crowded market with a bunch of Chinese suppliers (more than 50) and the adoption of VCM AF in mobile phone main camera is now almost 100%.  For VCM used in OIS applications, there are a few Japanese suppliers (which I mentioned in the previous question) who are technically proven.  The good thing for VCM OIS in mobile phones is that its proven technology where OEM pays less effort and time to market is short.

MEMS Journal: What makes your technology unique (e.g. process or device structure)?  Why can't your competitors do what you do?

Colin Kwan: We have a few ground-breaking patents for moving the image sensor inside a very small space while having a big stroke. This significantly enhances the OIS performance in mobile by allowing 3- axis (pitch, yaw, and roll axis stabilization).  Our competitors are moving the lens barrel, which means that they are limited to 2-axis compensation only.  Our actuator is using electrostatic comb drive instead of the VCM that uses using current drive which is almost impossible to get close to the power consumption used in MEMS.

MEMS Journal: What are your main advantages over your competition?  How do you compare on costs?

Colin Kwan: Our advantages are that we provide 3-axis instead of 2-axis stabilization, ultra-low power consumption, and high precision of movement.   Our long term cost will be competitive when we are fully ready to address the mass market.

MEMS Journal: What are the main challenges with your approach?

Colin Kwan: From system point of view, our performance exceeds current OIS systems.  However, we need other system partners to build new chips and enhance their software to fully realize the best possible capability of MEMS based OIS.  From manufacturing standpoint, our MEMS chip requires high precision assembly processes to enable high level of integration.

MEMS Journal: Flagship smartphones from leading OEMs are now starting to ship with dual cameras.  Does this have any implications for your solution?

Colin Kwan: There are challenges for manufacturing of dual cameras, especially with OIS in place.  This is actually another advantage that MEMS based OIS can bring to camera modules.  First, MEMS OIS solution does not have any coils and magnets, and therefore does not create cross talk issue when these components are placed in proximity.

The second challenge for dual cameras is that the optical axis alignment requirements of two cameras are very stringent.  High volume manufacturing for dual camera will require tight tolerance in assembly, calibration and test.  MEMS OIS can precisely move the image sensor in x-y plane and this can allow tuning the optical center by MEMS actuator without a very tight tolerance assembly of the module.

MEMS Journal: What is the actuation mechanism for your OIS product -- electrostatic, piezoelectric, or other?  How is this superior to existing solutions in the marketplace?

Colin Kwan: Our OIS actuator use electrostatic combo drive as the fundamental element.  Comb drive is extremely low power using voltage control.  The capacitance of combo drive can provide precise feedback without need of hall sensor or position sensor to save cost and space.

MEMS Journal: What type of materials are you using for your OIS actuator device?  Are you processing these devices on silicon wafers using standard semiconductor and MEMS processes?

Colin Kwan:  Our MEMS OIS actuator is made from silicon.  We use standard MEMS processes.

MEMS Journal: Are you planning to raise additional funding rounds or do you have a clear path to volume production with existing funds?

Colin Kwan:  We have planning to have additional round for further expand our capacity. With current funding, we are able to meet initial production volume needs.

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