Over the last year or so we have seen some smartphone manufacturers, including Xiaomi and Oppo, experimenting with under-display front cameras. The technology could allow for the design of displays without a 'notch' or front camera 'punch hole' but also means that incoming light has to first travel through the display before it hits the camera lens.

The latter is a major challenges to overcome and a reason why, according to Xiaomi VP Lu Weibing, we should not expect the technology to arrive any time soon in a production device.

Currently the pixel-dense displays of modern smartphones block too much of the incoming light. Combined with the small image sensors deployed in most front cameras this means the imaging module's light gathering capabilities are much more limited than on a more conventional camera, resulting in sub-par image quality.

Researchers and engineers are looking to develop technologies that allow for a combination of high pixel density and good light transmittance but are not quite there yet. Until the problem is solved there probably aren't too many consumers willing to sacrifice front camera image quality for a more streamlined device design which is we'll likely have to wait a little longer for the technology to make it into mass production.