LONDON – Cambridge Mechatronics Ltd. (CML), a developer of actuator technology used in consumer electronics, has demonstrated the application of its technology to optical image stabilization in a smartphone miniature camera.
CML (Cambridge, England) has created an actuator based on wires of nickel-titanium shape memory alloy (SMA) and an associated control and heating ASIC. The alloy has the property that it contracts and expands in a precise and reliable manner under heating and cooling.
The system uses a set of SMA wires to control the pitch and yaw of the lens in its housing and this must be done at frequencies of 1 to 30-Hz in response to gyroscope measurements of handshake, said CML CEO Simon Calder. The same technology is also used to control the z-position of the lens for focus.
CML has already succeeded in getting SMA-based control designed into cameras for autofocus. Mobile phones using AF technology are on sale in Japan, Calder said. But increasingly smartphone developers want to offer similar capabilities to digital still cameras, including OIS, but in a smaller and slimmer device.
Prototype smart-phone camera modules built to take advantage of CML's OIS actuation provide more than 24-dBs (more than 4 optical stops) of hand shake suppression, Calder said. This enables as much as a 20-fold increase in exposure times without hand-shake induced blur. This will help eradicate two weaknesses of smart-phone cameras, poor (or no) low-light performance and shaky video recordings. It also improves the quality of photographs taken in other conditions.
The SMA based system is smaller stronger and simpler and consumes less power than conventional system which is a voice-coil motor, Calder added.