reference will now be made in detail to the present preferred embodiments of the invention , examples of which are illustrated in the accompanying drawings . wherever possible , the same reference numbers are used in the drawings and the description to refer to the same or like parts . fig1 illustrates a cross sectional view of a heat dissipation device according to one embodiment of this invention . the heat dissipation device 100 includes a hollow housing 106 and a speaker 101 . the housing 106 has an opening 106 a and an opening 106 b . the speaker 101 is disposed at the opening 106 b , and electrically connected to a frequency signal source by a signal cable 108 . when the speaker 101 is driven by the frequency signal source , a diaphragm 102 of the speaker 101 oscillates along a direction 120 to cause forced air convection inside the housing 106 such that airflow is generated through the opening 106 a along a direction 130 . once the opening 106 a of the heat dissipation device 100 is directed towards a heat generating source ( i . e . an integrated circuit ), a heat dissipation purpose is achieved . in addition , a heat sink , i . e . a heat dissipation fin , is positioned within an area where the airflow along the direction 130 can reach ( i . e . adjacent to the opening 106 a ) such that the overall dissipation efficiency can be enhanced . in order to make the heat dissipation device 100 a silent one ( i . e . does not make any sound ), the diaphragm 102 of the speaker 101 oscillates within a frequency scope the human ear cannot hear , i . e . less than about 20 hz or larger than about 20 khz . in fact , the human ear hardly hear a frequency scope less than about 50 hz , even less than about 100 hz . although the speaker 101 has its original function of producing sound the human can hear , its diaphragm 102 materials may not necessarily be varied in this silent heat dissipation device . as long as the diaphragm 102 can oscillate properly within a frequency scope the human ear cannot or hardly hear , the diaphragm 102 materials can be the same as a common speaker &# 39 ; s . the speaker 100 structure is similar as speakers in general market . in particular , the diaphragm 102 includes a magnet 102 a and the speaker 101 includes a magnetic inductive coil 104 . in addition , the speaker 101 includes at least one opening 103 to allow the oscillation of the diaphragm 102 to induce airflow along the direction 130 . fig2 illustrates a cross sectional view of a heat dissipation device according to another embodiment of this invention . this embodiment employs the same operation principle of last embodiment to provide another heat dissipation device 200 . a housing 206 has an opening 206 a and an opening 206 b . a diaphragm 202 with a magnet 202 a is disposed at the opening 206 b . a magnetic circuit ( including a ferrite 210 and a magnetic inductive coil 212 around the ferrite 210 ) operatively coupled with the diaphragm 202 is installed inside the hollow housing 206 , and electrically connected to a frequency signal source by a signal cable 208 . when the magnetic circuit ( the magnetic inductive coil 212 ) is electrified , i . e . by the frequency signal source , the diaphragm 202 oscillates along a direction 220 within a frequency scope the human ear cannot hear , i . e . less than about 20 hz or larger than about 20 khz . in fact , the human ear can hardly hear a frequency scope less than about 50 hz , even less than about 100 hz . air inside the hollow housing 206 is forced to flow along the direction 230 . a heat sink 240 , i . e . a heat dissipation fin , is positioned within an area where the airflow along the direction 130 can reach ( i . e . adjacent to the opening 206 a ) such that the overall dissipation efficiency can be enhanced . thus , the heat dissipation device of the present invention can provide forced air convection to achieve a heat dissipation function without making noises . it will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention . in view of the foregoing , it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents .