Patent Application
20080089031
Referring to
The heat sink 10 comprises a base 11, a plurality of fins 12 extending up from the base 11, and four legs 110 extending down from four corners of the base 11. Each leg 110 is in a ladder shape, including a supporting portion 111 with a large cross section, and an inserting portion 112 with a small cross section, which extends down from the supporting portion 111. The PCB 20 defines four holes 21 corresponding to the four legs 110 of the heat sink 10 respectively. A cross section of each of the holes 21 is larger than that of the inserting portion 112 but smaller than that of the supporting portion 111 to stop the supporting portion 111 passing through the holes 21. An upright length of the supporting portion 112 is greater than a thickness of the chip 30. The chip 30 is attached on the PCB 20 among the four holes 21. A layer of a heat-conduction medium 40 is disposed on a top surface of the chip 30.
In assembly of the heat sink 10 onto the PCB 20, the inserting portions 112 of the heat sink 10 are inserted in the holes 21 of the PCB 20 respectively until the supporting portions 111 resist the top surface of the PCB 20, and the heat sink 10 is compressing the layer of heat-conduction medium 40. Because the supporting portions 111 contact on the PCB 20, pressure from the heat sink 10 is distributed between the chip 30 and the PCB 20, protecting the chip 30. The parts of the inserting portions 112 that pass through the holes 21 may be fastened to the bottom surface of the PCB 20, by soldering, gluing, and so on.
Referring to
The heat sink 110′ comprises a base 11′, a plurality of fins 12′ extending up from the base 11′, and four legs 110′ extending down from the base 11′. A layer of heat-conduction medium 50′ is disposed on a top surface of the chip 30′. The upright length of the leg 110′ is greater than that of the chip 30′. The heat sink clip 40′ defines two latching members 41′ at the end of the heat sink clip 40′. The PCB 20′ defines two latching rings 21′ corresponding to the latching members 41′.
In assembling the heat sink 10′ onto the PCB 20′, the heat sink 10′ is laid on the PCB 20′, compressing the layer of heat-conduction medium 50′. Distal ends of the legs 110′ away from the base 11′ contact the top surface of the PCB 20′. Because the legs 110′ contact on the PCB 20′, pressure from the heat sink 10′ is distributed between the chip 30′ and the PCB 20′, protecting the chip 30′. Then, the heat sink clip 40′ is mounted on the base 11′ of the heat sink 10′ and the latching members 41′ clasp the latching rings of the PCB 20′. Thus, the heat sink 10 is fastened on the PCB 20′, as best shown in
In the above embodiments of the present invention, the legs may be of greater number and have different shapes. The PCB may define a plurality of flutes corresponding to the legs of the heat sink. The legs of the heat sink may be formed separately then connected to the heat sink.
It is to be understood, however, that even though numerous characteristics and advantages have been set forth in the foregoing description of preferred embodiments, together with details of the structures and functions of the preferred embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
