Big news is coming out of Sony and it’s that they’ve developed a back-illuminated CMOS sensor that enables global shutter function. Now, the sensor is only 1.46 megapixels, so don’t expect it to be integrated into any Sony cameras anytime soon, but regardless, it's still a big feat for Sony.
The advantage of backlit CMOS sensor is that it basically allows cameras to capture images at lower light levels with a lot less noise. This is because the sensor’s electric circuits are placed at the back of the sensor, not the front, meaning that more light can get to the photosites and less readout amplification is required.
Sony has designed the sensor with a new pixel-parallel A/D converter that they report enables global shutter.
“The new Sony sensor comes with newly developed low current, compact A/D converters positioned beneath each pixel. These A/D converters instantly convert the analog signal from all the simultaneously exposed pixels in parallel to a digital signal to temporarily store it in digital memory. This architecture eliminates focal distortion due to readout time shift, making it possible to provide a Global Shutter function, an industry first for a high sensitivity back illuminated CMOS sensor,” says Sony.
Additionally, Sony says that the sensor’s new readout circuit can uses 1.46 million converters in high speed, allowing for a high data transfer rate.
Sony also has developed something called Cu-Cu connection that they said allows the privilege of the parallel analog to digital conversion.
“To achieve the parallel A/D conversion for all pixels, Sony has developed a technology which makes it possible to include approximately three million Cu-Cu connections in one sensor. The Cu-Cu connection provides electrical continuity between the pixel and logic substrate, while securing space for implementing as many as 1.46 million A/D converters, the same number as the effective megapixels, as well as the digital memory,” says Sony.
So, in summary, the new sensor allows cameras to shoot at lower noise levels and allows filmmakers to shoot without rolling shutter. The big question, though, is if the the video industry really needs global shutter. Sony's not the only company investing into global shutter; Panasonic's announced that they've developed an 8K global shutter CMOS sensor. What do you think? Should companies like Sony and Panasonic be investing their time into global shutter, or are cameras already good enough with rolling shutter? If you’re not sure what the difference between global and rolling shutter is, be sure to watch the video below so we can help explain the difference.