With nearly two billion mobile phones and 800 million digital cameras shipping each year, there has been an ongoing need for faster focus, rapid picture taking, and continuous auto focus for clearer video capture. A key motion technology that has emerged in these applications is piezoelectric micro motors, which, coupled with innovative micro-mechanical design, is minimizing lens tilt and enabling extremely high-precision imaging in micro-camera formats.
New Scale Technologies offers a micro-motion design solution for phones and cameras based on its piezoelectric motor, which uses an ultrasonically vibrating beam. This approach uses custom, ultra-thin, auto focus actuators that combine a motor with a linear guide mechanism to create an autofocus lens module. The beam is oriented perpendicular to the optical axis, and contacts the lens at two points to maximize stability and driving force.
The technology uses a unique vibration mode that optimizes resolution and speed for the autofocus function. The actuator assembly is only 3.8 mm high, and is thinner than the lens assembly, so the lens, not the motor, determines the module size.
According to the press release :
- New Scale Technologies, Inc. has received a U.S. patent for its UTAF (ultra-thin auto focus) piezoelectric lens actuator module measuring only 8.5 x 8.5 x 3.8 mm. The UTAF actuator module integrates New Scale's UTAF piezoelectric beam motor with a drive IC and position sensor IC for closed-loop motion control. Patent # 8,279,541 extends coverage to the module's precision pin bushing system that moves the lens in a straight line with dynamic tilt of less than 0.1 degree. This low tilt is a critical requirement for high-megapixel cameras and imaging systems. The patent also covers a unique flexure preload or magnetic preload system that produces substantially zero additional friction in the bearing guide, irrespective of the location along the optical centerline. This allows the module to lift a mass at least three times greater than the typical lens mass of 0.25 grams, insuring a low sensitivity to gravity orientation for the camera system...
"This precision lens actuator module enables development of high-performance vision systems that fit into smaller and smaller form factors -- from thin smart phones, to ultra-compact devices for medical imaging and diagnostics," said David Henderson, CTO and co-CEO of New Scale Technologies. "At the same time, our high level of electronic and mechatronic integration makes it easier for system designers to use this powerful new technology: they simply provide high-level digital commands for step and velocity over a standard SPI or I2C interface."
The UTAF motor is produced under license by New Scale's technology partner, TDK-EPC (EPCOS), using multi-layer co-fired ceramic processing. It is manufactured as a single part that operates directly from the phone battery, less than 2.8 V.