Ultra-thin heat pipe and ultra-thin VC

Ultra-thin heat pipe and ultra-thin VC

      Because flattening can damage the capillary structure inside the heat pipe, the capillary structure of ultra-thin heat pipes is different from conventional heat pipes. The inner wall of a conventional heat pipe often has a loop of capillary structure, and the capillary structure of an ultra-thin heat pipe is usually only in the middle. When the heat pipe is flattened, the capillary structure does not follow the pipe wall to bend, but is only compressed. This reduces the damage to the capillary structure caused by the flattening.

  Because the heat pipe is very thin, its maximum heat transfer is very small. For example, the maximum heat transfer capacity of a 0.4mm thick heat pipe is only ~ 3W. In addition, although the central capillary structure is used, when the heat pipe is flattened, the copper walls on both sides will inevitably be deformed. Therefore, a 0.4 mm thick heat pipe can be photographed, and its original pipe diameter is not large (usually (More than 5mm-September 2019 data). This results in a limited width of the heat pipe after shooting, which affects the effect of soaking. In addition, after the heat pipe is flattened, the steam channel is completely hollow, and because the copper wall is thin (usually <0.15mm), its compressive or bending strength is very poor. In summary, the ultra-thin heat pipe has the following disadvantages:
1) Low maximum heat transfer;
2) Can only be close to one-dimensional soaking, the area of ​​soaking is limited;
3) Low mechanical strength

Similarly, due to the small internal space, the capillary structure of ultra-thin VC is also different from that of traditional VC. According to the technology in 2019, ultra-thin VC uses etching technology to etch the boss on the copper plate, and the boss plays a supporting role. The other copper plate is fitted with a copper mesh inside as a capillary structure. The gap between the copper pillars is the steam flow channel, and the copper mesh is the liquid return channel [4]. Etching, welding, filling, vacuuming, sealing, etc. of such a thin copper plate are all difficult problems. This results in lower yield and higher cost of the current ultra-thin VC.