(Pocket-lint) - The arms race is very real, in smartphone camera terms - we're starting to pass out of the phase where every major phone has a similar camera unit and system attached to it. We've seen handsets with flip-up cameras, pop-up selfie shooters and it looks like under-display lenses could be around the corner, too.

Now Oppo has tilted its hand a little, letting us see that it's working on another tactic entirely - a camera unit that can be completely detached from its smartphone. The clear caveat at this stage is that this comes in the form of a patent filing to the World Intellectual Property Office (WIPO), rather than in a working concept or announced model. 

The patent shows an intriguing design that has a camera module that can be removed from the smartphone housing it, with its own small USB-C connector allowing it to be secured in place. That connector also appears to allow for a design where the module could be plugged into the phone's charging port to turn into a selfie-unit when needed. The connector can even seemingly be placed at different angles to let you shoot in more ways. 

Plus, the camera unit would apparently have its own self-contained battery and the potential to connect back to your phone via Bluetooth, Wi-Fi or NFC wirelessly, meaning that you could even use it as a remote camera, view-finding and activating the shutter using the phone's screen. 

As is often the case, it's worth reiterating that a patent is far from confirmation that this will ever get to market or be worth Oppo's time to actually build, but it's nonetheless an interesting example of how manufacturers are seeking to keep things fresh and find new offerings when it comes to smartphone photography. 

Writing by Max Freeman-Mills.