Your presentation focuses on “Deep Well” pixel HDR technology. Can you explain what this means in a little more detail?
In general, high dynamic range (HDR) imaging relies on digital photographic techniques that expand the scope of luminosity to duplicate the human visual experience. This allows us to recreate balanced scenes regardless of lighting conditions. All of OmniVision’s HDR pixel technologies enable image capture in both bright and dark areas at the same time to produce image and video with balanced lighting. Deep Well HDR is the most advanced of these technologies.
“Deep Well” refers to full-well capacity. Our sensors have a full-well capacity of 50,000 electrons, which translates to 2-3 times larger than what is typical for 2.8µm pixels. Additionally, the pixels are read out with both high gain (for dark objects) and low gain (for bright objects) simultaneously, thus achieving HDR with one single exposure.
How is this different than other HDR technologies?
Most other HDR techniques require multiple exposures (e.g., multiple integration times) to achieve the same dynamic range. This often leads to ghosting artifacts after combining the data into one HDR pixel value when there are fast-moving objects in the scene. This is the case with industry-standard dual-gang conversion HDR, which snaps two image shots in succession before conversion to create the image. Alternatively, OmniVision’s Deep Well pixel HDR unleashes full-pixel technology in one shot that generates a single readout charge with both low- and high-conversion gain to produce sharp images without motion artifacts.
As a regular attendee and conference chair in the past, you must have heard a number of forecasts and trends predicted over the years; where do you foresee the image sensor market is headed in the next 5 years?
The image sensor market is exploding across multiple applications from smartphones, wearables and augmented/virtual reality to automotive, medical, security and surveillance, and industrial sectors thanks to trends like the internet of things, driver-assist and autonomous vehicles, smart homes, cities and industry. From a technology perspective, we’re noticing that the pixel war (pixel shrink) is slowing down, and there is more focus on differentiating features such as HDR, global shutter, backside illumination (BSI), wide-angle and optical zoom for dual cameras, all targeting improved image performance benefits such as low-light performance, sharper, crisper images, and more.
In 5 years, we expect most sensors will be stacked sensors using backside illumination, which gives better image quality thanks to CMOS process nodes that are more optimized for its purpose. This applies to all markets, not just consumer cameras.
And what would you say over the last 10 years have been the biggest game changes for the industry?
From my perspective, the biggest game changers in image sensor technology have been BSI image sensors and stacked wafer technology, both of which are featured in the OmniVision product line. BSI reverses the order of the photodiode and circuitry, creating a more direct path for light to reach the pixels, providing a leap in low-light performance and signal-to-noise ratio by enabling smaller pixels. Further, our second-generation BSI technology is based on 65nm node semiconductor 300mm wafers to create the industry’s first 1.1-micron pixel image sensor, and provides low-light sensitivity and advancements in dark current and full-well capacity.
Stack technology is a two (or more) wafer solution that leads to smaller die size and higher-level integration opportunities with advanced camera features.
What can the attendees look to gain by hearing your presentation and attending the conference?
My presentation will give a good understanding of both the benefits and limitations of the new HDR technology. In general, IS London gives an excellent overview of what’s going on in this industry, and is one of the best networking conferences I know of thanks to the organization and its facilities.
What are you most looking forward to at the 10-year anniversary edition of the Image Sensors Europe 2017
There are several things I’m looking forward to at this year’s edition. I’m especially interested in being brought up-to-date on market trends and learning what our camera module customers will be requiring from image sensor manufacturers. Moreover, I'm looking forward to the new awards program, and who will be recognized for their achievements.