The VCM is used in many image sensors today but OmniVision has coupled its 23.8-magapixel OV23850 sensor with a MEMS from Wavelens to produce a high-speed autofocus and bring digital still camera functionality to high-end smartphones.
The OV23850 is capable of recording quad high definition (QHD) video at 30 fps in HDR mode to enable ‘always on’ HDR preview mode for a resolution size popular with flagship smartphone displays. Additionally, the sensors support 720p HD video at 120 fps and 1080p HD video at 90 fps, allowing for crisp slow motion video recording.
Wavelens has developed three optical MEMS with different optical apertures and dimensions to cater form a few megapixels to more than 20 megapixels.
Wavelens’ optical MEMS consists of an optical membrane released onto an optical oil-filled cavity, with MEMS actuators embedded at the membrane periphery. As an operating principle, when the MEMS are actuated, the optical oil flows through the membrane center-modifying the membrane’s curvature and introducing a focal length variation.
This smart combination of the flexible membrane and the optical oil makes possible an efficient and powerful variable focus component.
Since the MEMS actuators are embedded at the membrane periphery, Wavelens technology is very competitive in term of compactness (ratio between MEMS outline and optical aperture).
Thanks to the optical oil, the voltage required is typically below 10V, because of the low force needed to change the membrane curvature, and the power efficiency is very high. The optical power variation required for Autofocus application (at least 10 diopters) can easily be achieved for a wide range of optical MEMS aperture.
Wavelens optical MEMS has a functional thickness less than 100-microns.
"With our partnership with OmniVision, we are able to fully leverage the high-speed focus and low-power consumption that our MEMS-based autofocus technology offers," said Sebastien Bolis, CEO at Wavelens, in a statement. "Together, we are redefining what users can do with a smartphone camera, allowing them to take rapid multi-frame captures or to have continuous autofocus during video capturing."
"The OV23850 supports fast-auto focus modes and is our highest resolution image sensor currently available, which makes it the preferred sensor for the MEMS focus technology developed by Wavelens," said Tehzeeb Gunja, senior partnership and business development manager at OmniVision, in the same statement. "VCM-based autofocus, while a proven technology, suffers from slow speed to focus and high current consumption. We are excited to take part in the transition to a superior MEMs-based solution that can overcome VCM’s shortcomings. OmniVision is working with Wavelens to bring to market the MEMS-based autofocus technology across a wide array of sensors."
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