SHANGHAI A handful of companies are zooming in on digital auto focus for handset cameras. The technology comes just as system designers are looking to transition to 3-megapixel platforms and it should lower costs as well as slim down module size by doing away with the motors and actuators used today.
MagnaChip Semiconductor, OmniVision Technologies, and STMicroelectronics are all planning digital auto focus products. Engineers at MagnaChip have spent the last six months collaborating with French IP provider DxO Labs on a system-on-chip that combines a digital auto focus engine with a 3-megapixel sensor and an image signal processor.
At this week's 3GSM World Congress in Barcelona, STMicroelectronics also said it would work with DxO to create a complete module. OmniVision also unveiled its 3-megapixel TrueFocus camera, based on its Wavefront Coding technology.
Cell phone camera module makers are interested in moving from 2-megapixel, fixed-focus modules to 3 megapixel without using auto focus lenses and actuators in the modules. "This is the place where we think people have run up against a little bit of a barrier," said Jason Hartlove, senior vice president of the Imaging Solutions Division at MagnaChip. "Because of the resolution and sharpness at 3 megapixel, you begin to see the lack of depth of field in a regular fixed-focus lens."
Jean-Claude Rosichini, vice president of marketing for DxO's Embedded Imaging Solutions, said taking out the mechanical actuator increases reliability of the module, cuts costs and size and adds in additional features unavailable from today's offerings. "Mechanical auto focus cannot provide extended depth of field," he said. "So now you will get sharpness from as close as 10 centimeters up to infinity."
OmniVision is also moving aggressively to carve out market share for its Wavefront technology, a method of optically encoding light using a special lens to form an intermediate image on the sensor, and then decoding this intermediate image with digital processing to create a picture that is in focus across most of the frame, the company said. A TrueFocus camera comprises a Wavefront Coded lens, a 3-megapixel CMOS image sensor, and an image signal processor.
Ed Dowski, president of CDM Optics, a subsidiary of OmniVision, noted that traditional imaging optics have remained basically the same for "several hundred years." He believes that digital auto focus now submits optics to the power of Moore's Law, enabling a quick decline in cost for module makers.