This has been a saga and a half. Way back in February 2018, Panasonic announced an organic 8K global shutter CMOS sensor. Later that year, they announced the first camera containing this sensor. Although, they didn’t really announce them. Neither the sensor nor the camera actually existed. It wasn’t until September 2019 that we were finally told what was going on when they made a development announcement for the sensor.
A prototype camera was spotted at a show in Japan in November 2021, but there was still no information on availability or prices. Now, though, it seems that Panasonic has finally, officially, fully developed the sensor, according to a new announcement this month. Do they finally have an 8K camera on the way?
The press release, with the rather long-winded title, Panasonic Develops Organic Photoconductive Film (OPF) CMOS Image Sensor Technology That Achieves Excellent Color Reproducibility under Any Light Source Irradiation, essentially says that they’ve done it now. The sensor exists. What makes it so special? Well, the biggest thing is that it’s a global shutter sensor.
Organic Photoconductive Film
OPF sensors work differently from a more traditional Bayer sensor array, the latter of which Panasonic says “[does] not have sufficient color separation performance for green, red, and blue”, resulting in inaccurate colour representation. Panasonic’s solution to these problems is the Organic Photoconductive Film, or OPF, sensor. OPF’s unique structure uses an organic film to turn light into electrical signals, separated from the parts responsible for storing and reading those signals.
Here’s some of the Abstract from the press release:
Panasonic Develops Organic Photoconductive Film (OPF) CMOS Image Sensor Technology That Achieves Excellent Color Reproducibility under Any Light Source Irradiation
Conventional Bayer array-type silicon image sensors do not have sufficient color separation performance for green, red, and blue. Therefore, for example, under light sources that have peaks at specific wavelengths, such as cyan light and magenta light, it has been difficult to accurately reproduce, recognize, and judge colors.
Our OPF CMOS image sensor has a unique structure in which the photoelectric conversion part that converts light into an electric signal is an organic thin film, and the function of storing and reading out the signal charge is performed in the circuit part, which are completely independent from each other (Figure 1). As a result, unlike with conventional silicon image sensors, it is possible to provide photoelectric conversion characteristics that do not depend on the physical properties of silicon.
The OPF with its high light absorption rate enables the thinning of the photoelectric conversion part ((1) Photoelectric conversion film thinning technology). By providing a discharge electrode at the pixel boundaries, the signal charge due to the incident light at the pixel boundaries is discharged, and the signal charge from adjacent pixels is suppressed ((2) Electrical pixel isolation technology).
So, essentially, their technology splits every individual pixel element up from its neighbour to prevent cross-talk and pollution spilling over from one colour channel to the next. As well as allowing the sensor to operate in a global shutter fashion, capturing the entire frame simultaneously rather than line-by-line like traditional CMOS sensors, this should hypothetically help to reduce noise, too. We should be able to ramp up the ISO (thanks to the claimed 10x light absorption) with the sensor seeing less pollution from adjacent pixels and colour channels spilling into each pixel and each pixel element. However, how well any noise improvements – particularly as a result of increasing ISO – will appear in the real world remains to be seen.
You can read Panasonic’s complete announcement here. However, there’s still no news on when Panasonic will have these in mass production or when we’ll finally see that 8K camera they’ve been teasing for half a decade.