US Patent 7137442 Vapor chamber

A vapor chamber, in which a condensable fluid, which evaporates and condenses depending on a state of input and radiation of a heat, is encapsulated in a hollow and flat sealed receptacle as a liquid phase working fluid; and in which the wick for creating the capillary pressure by moistening by the working fluid is arranged in said sealed receptacle, comprising: a wick for creating a great capillary pressure by being moistened by said working fluid, which is arranged on the evaporating part side where the heat is input from outside; and a wick having a small flow resistance against the moistening working fluid, which is arranged on the condensing part side where the heat is radiated to outside.