Foldable smartphones will be widely commercialized in the next few years. A foldable smartphone will be folded while being carried, therefore, a smaller thickness than a regular smartphone is desired. Reduction in thickness leads to thermal issues, especially in 5G devices.
With the potential use of organic light emitting diode (OLED) or other sensitive materials in next-generation smartphones, the temperature difference across the surface of smartphone is an important design consideration. Temperature difference could be reduced using efficient heat spreaders. Thermal ground plane (TGP) or vapor chamber is the 2-D version of heat pipe which is a highly efficient heat spreader. The current design of TGP fails to maintain its performance after being folded, therefore, it cannot be used for spreading heat in a foldable device.
The reason for this failure is the buckling and wrinkling which leads to clogging of the vapor flow in the TGP. We have developed a TGP without this clogging issue. In this presentation, thermal testing on this foldable TGP will be reported.