Xiaomi officially announced the arrival of the new Mi 4i smartphone in Malaysia yesterday. After the event, selected members of the media were invited to a unique teardown session with Donovan Sung, Xiaomi Global’s Director of Product Management. Xiaomi is especially proud of the Mi 4i’s construction and in the efficiency of its design, and the company was keen to show us what’s underneath the polycarbonate unibody.
The back cover can actually be easily removed using a spudger (Xiaomi says even a guitar pick might work). The SIM tray needs to be removed first, though.
A standard Phillips #00 screwdriver opens all the necessary screws required to access the circuit boards. Sung says even the screws were sourced from the best companies that make them.
The Mi 4i’s battery is actually removable. A little tab near the bottom right side of the device allows the 3,120mAh battery to be safely removed.
The Mi 4i uses two printed circuit boards (PCBs), located at the top and bottom of the device. They’re connected by two strips of connectivity cables, which Xiaomi says is a lot more efficient in design.
The top houses the processor, memory and storage modules as well as the camera modules.
The bottom houses the charging module and the speakers.
The Mi 4i uses a dual-sided PCB, allowing the board’s physical size to be significantly smaller, allowing Xiaomi to fit in a battery that’s as thick as the device itself. (Not pictured: the 13MP Sony IMX 214 camera module – it’s located at the top right of the PCB above, where the square gap is.)
The Mi 4i’s PCB, including the camera module. It is the smallest – and densest – PCB ever designed by Xiaomi.
Xiaomi patented the “floating” camera design, where the camera module is bound to the PCB via a thin connector, allowing it to fit flush in the final device – no camera bumps.
Next, Sung shows off the Mi 4i’s display panel. Using an one-glass solution (OGS) panel, what you see above is the Corning protective glass, digitizer and LCD all in one exceptionally thin strip of glass.
To demontrate just how thin it is, Sung whips out a credit card – the screen is only marginally thicker.
After the teardown, Sung casually fitted everything back together, powering it on like it’s something he does every day. He probably does.
