Sony’s latest imaging sensor reads like a list of photography buzzwords: Backlit, global shutter, stacked sensor. But using a new design, Sony was able to mix all three sensor technologies into a single unit, the company shared on Monday, March 18. The result is a sensor that solves several image quality concerns using a sensor with a global shutter and a design that’s both stacked and backlit.
Global shutter sensors have been under development for a while, designed to expose the entire image at once instead of a row of pixels at a time. The change prevents a common type of high-speed distortion called focal plane distortion where moving objects appear to bend or lean.
In order to expose the entire image at once, global shutter sensors use temporary data storage, allowing the image data to be captured from the exact same time. The problem is that in order to temporarily store that data, the traditional design requires wiring and other components at the front and to the side of the sensor.
Positioning parts of the sensor at the front blocks light, leading to poorer low-light performance. That reduced performance becomes an issue in high-resolution sensors because more pixels mean smaller pixels, which are less capable of gathering light. Switching to a backlit design, Sony says, negates the effect of increased resolution on low-light performance. The result? A global shutter sensor that offers high resolution, without sacrificing so much low-light performance.
Using a new pixel structure, Sony managed to move the metal wirings to the back, while leaving the memory storage at the side, but further back in the design. Sony says the design results in 1.7 times higher resolution than a sensor that is frontlit, turning a 12-megapixel sensor into a 20-megapixel one.
The new sensor also uses Sony’s stacked sensor design, which adds a third layer of temporary memory. Because of that extra memory, stacked sensors can gather data at a faster rate, which translates into features like the 20 fps full-frame Sony a9. Sony says the new sensor is about 2.4 times faster than earlier global shutters.
While the new Sony sensor contains a list of new design features, it’s first destined for manufacturing and inspection, not mirrorless cameras or smartphones. Early sensor technology has a tendency to be used in high-cost manufacturing and inspection equipment first, but there is always the possibility that the tech trickles down to more widely available uses.
