Heat sink structure

1. A heat sink structure comprising:

a base seat having a first face and a second face, at least one extension column correspondingly vertically extending from a periphery of four corners of the second face of the base seat, and together defining a support space, a support section located on the at least one extension column and above the base seat and between an upward extending section of the at least one extension column and the base seat to divide the support space into an upper space and a lower space; and

at least one heat dissipation unit composed of multiple radiating fin assemblies, the support section and the base seat respectively serving to secure and support the multiple radiating fin assemblies in the upper space and the lower space, such that the multiple radiating fin assemblies are stacked as an upper layer and a lower layer by means of the support section, a gap existing between the radiating fin assemblies in a vertical direction, and wherein the base seat, the extension column and the support section together restrict or secure the heat dissipation unit in horizontal and vertical directions.

2. The heat sink structure as claimed in claim 1 , wherein the heat dissipation unit is a radiating fin assembly composed of multiple radiating fins, which are arranged at intervals and connected with each other by means of lap joint or engagement or latching.

3. The heat sink structure as claimed in claim 1 , wherein the at least one extension column includes a first extension column, a second extension column, a third extension column and a fourth extension column, the first, second, third and fourth extension columns being respectively disposed on four corners of the base seat.

4. The heat sink structure as claimed in claim 1 , wherein the heat dissipation unit is composed of a first radiating fin assembly and a second radiating fin assembly, the first and second radiating fin assemblies being arranged as an upper layer and a lower layer and secured by the extension columns, the first radiating fin assembly being composed of multiple first radiating fins, each first radiating fin having a first thickness, a first gap being defined between each two adjacent first radiating fins, the second radiating fin assembly being composed of multiple second radiating fins, each second radiating fin having a second thickness, a second gap being defined between each two adjacent second radiating fins, the first thickness being larger than or smaller than the second thickness, the first gap being larger than or smaller than the second gap.

5. The heat sink structure as claimed in claim 4 , wherein the first radiating fins have a configuration identical to or different from a configuration of the second radiating fins.

6. The heat sink structure as claimed in claim 4 , wherein the first radiating fins have a height equal to or unequal to a height of the second radiating fins.

7. The heat sink structure as claimed in claim 1 , wherein vacuumed airtight chambers are disposed in an interior of the base seat and an interior of the extension column for heat exchange of two-phase fluid, the vacuumed airtight chamber of the extension column being selectively in communication with the vacuumed airtight chamber of the base seat or not in communication with the vacuumed airtight chamber of the base seat.

8. The heat sink structure as claimed in claim 1 , wherein the base seat has a heat dissipation section, the heat dissipation section being formed in such a manner that the heat dissipation section directly upward extends from the second face of the base seat.