Abstract: A vapor chamber having improved heat transfer capacity by efficiently returning the working fluid to the evaporating portion is provided. A hollow flat container 2 is formed by a base member 4 and a lid 3 closing an opening of the base member. Phase-changeable working fluid is held in the container, and fins 9 are arranged in the container to transmit heat of a heat generating object between the bottom plate of the base member and the lid. The fins are densely juxtaposed on an evaporating portion in comparison with the other fins juxtaposed on the outside of the evaporating portion.

Abstract: A vapor chamber includes: an upper plate; a lower plate; a plurality of side walls disposed between the upper plate and the lower plate; a wick body that is disposed in a space sealed by the upper plate, the lower plate, and the side walls and that contacts the upper plate and the lower plate; and a pillar that is disposed in the space and contacts the upper plate and the lower plate. The wick body includes first wick portions each including a first terminal positioned in a vaporization portion, a linear portion, and a second terminal, wherein each of the first wick portions extends to the side walls from the first terminal, and a second wick portion that connects the second terminals of the first wick portions to each other.

Abstract: In a heat spreading module, a plurality of hollow paths is formed in a thin plate-shaped main body so as to pass though the heating portion, and the hollow paths communicate with each other in a heating portion, a working fluid is enclosed in the hollow paths, a wick is disposed in each of the hollow paths such that a vapor flow path in which vapor of the working fluid flows is formed in each of the hollow paths, a part of each wick is positioned at the heating portion, and the vapor flow paths formed in the hollow paths communicate with each other in the heating portion.

Abstract: A heat pipe having a wick structure for efficiently returning working fluid to an evaporating portion is provided. The heat pipe comprises a container 2 sealed at its both ends, a working fluid encapsulated in the container, and a wick structure 10 covering an inner face of the container. The wick structure 10 includes a porous wick 11 of a sintered metal powder, and a fiber wick 12 buried in the porous wick. A capillary pressure of the fiber wick 12 is weaker than that of the porous wick 11, and a pressure loss of the fiber wick 12 is smaller than that of the porous wick 11.

Abstract: In a heat spreading module, a plurality of hollow paths is formed in a thin plate-shaped main body so as to pass though the heating portion, and the hollow paths communicate with each other in a heating portion, a working fluid is enclosed in the hollow paths, a wick is disposed in each of the hollow paths such that a vapor flow path in which vapor of the working fluid flows is formed in each of the hollow paths, a part of each wick is positioned at the heating portion, and the vapor flow paths formed in the hollow paths communicate with each other in the heating portion.