According to a patent filed by Sony, fans might soon be able to upgrade their DualSense controllers with a back button that adds more features. This wouldn't be the first time that PlayStation fans have seen something like this, as the DualShock 4 controller for PS4 had something very similar, but it is the first mention of a new design for the current generation of gaming. Though patents like this are typically somewhat difficult to read, a lot can be learned by examining it and more can be inferred by looking at the previous rendition of a back button for PlayStation gaming.
It should be said that Sony hasn't made any kind of announcement about a PS5 DualSense back button, so this is technically not official yet. The existence of a patent implies that it's something the company is considering and maybe even working on, but this is by no means a guarantee of this product coming to players in the near future.
Officially referred to as a "controller add-on device with customizable presets," the images filed with the patent show that this is indeed some type of back button. In terms of the back button already on the market for the DualShock 4 controller, it has two primary functions. Since it adds two more mappable buttons to the back of the controller, competitive players can use it to perform certain inputs faster and with greater ease. Perhaps more important than this, though, is its application for disabled gamers. Sometimes it can be difficult for disabled gamers to make use of the spread out buttons of PlayStation controllers, and this helps with that.
Aside from being made specifically for the DualSense controller, it doesn't look as though it will function much differently. More likely than not, it will add at least two new buttons to the controller, and since they are customizable players should be able to map them to anything they want. The DualShock 4 back button was very popular, so it's likely that this one will perform well too.
Though this isn't a huge surprise, the timing of these releases does seem strange. Sony released the DualShock 4 back button in January of 2020, just a few short months before the reveal of its next generation DualSense controller. These PS5 controllers don't support the back button already on the market, and it feels like a lot of extra work for everyone to have a separate one for the DualSense as well.
Source: Gaming Route; WIPO