摘要
This work presents the performance test results for novel two-piece ultra-thin vapor chambers with a thickness (t) of 0.38 mm, 0.48 mm and 0.58 mm, having a vapor duct thickness (h) of 0.15 mm, 0.25 mm, and 0.35 mm, respectively. These ultra-thin vapor chambers simply comprise a top plate etched with arrayed pillars as the condenser and a mesh-wicked bottom plate as the evaporator and liquid path. The inner surface of the top plate contains cross parallel vapor ducts configured by aligned pillars for vapor spreading all over the vapor chamber. The pillars provide strong structural support, an enlarged condensation area, and a direct shortcut for liquid return. Compared to traditional vapor chambers, the novel ultra-thin vapor chambers have the advantages of simpler structure, easier manufacturing process, lower cost, superior anti-compression ability, and better thermal performance. They keep excellent structural integrity at a footprint of 140 mm × 80 mm. Cooled by natural convection, the vapor chamber resistances (R vc s) are measured for different hs at different filling ratios (γs). Capillary blocking is observed for h = 0.15 mm and 0.25 mm at γ larger than 1.0, but it does not appear for h = 0.35 mm even with considerable over-charge. Although capillary blocking may slightly raise R vc s, it can be avoided by suitable under-charging. Except for cases with significant over-charge, R vc s are similar for h of 0.15 mm to 0.35 mm at heat loads less than 15 W due to the low vapor resistances at low mass flow rates. At heat loads of about 14 W, the minimum R vc s of unblocked ultra-thin vapor chambers are about 0.25 K/W to 0.3 K/W, greatly superior to the value of 0.88 K/W of a 0.5 mm-thick copper plate.