It was rumored around five months ago that the Galaxy S8 was going to be the first smartphone with optical fingerprint recognition. This would mean that the handset's display was going to feature an integrated fingerprint sensor. Samsung was already expected to ditch the physical home button so it had to put the sensor somewhere and integrating it with the display felt like the natural choice.
However, we now know that the Galaxy S8's fingerprint sensor has actually been relocated to the back alongside the rear sensor. It's a bit unorthodox as we've seen in leaked images and videos of the Galaxy S8 but there's no going back from this now. A new report out of Korea explains the reason why the Galaxy S8 doesn't have optical fingerprint recognition.
The optical fingerprint recognition technology is still nascent and the report claims that Samsung and its fingerprint sensor supplier Synaptics were running out of time. Even though Samsung poured resources into Synaptics' nascent technology last year, “the results were frustrating.”
The company had to make a decision as it had to start mass production of the Galaxy S8. It made a last minute decision to relocate the fingerprint sensor to the back. Samsung reportedly tried its best to have an embedded fingerprint sensor in the Galaxy S8's display but Synaptics was unable to develop the technology on time.
It's pertinent to mention here that none of this has been confirmed by Samsung or Synaptics so take it with a grain of salt.
Samsung is likely to market the iris scanning and facial recognition features of the Galaxy S8 more to steal the spotlight from the fingerprint sensor. It remains to be seen when this technology will be fully developed so that it might be integrated into future Samsung flagships.