Patent Document

RELATED APPLICATIONS 
     The present application is based on, and claims priority from, Taiwan Application Serial Number 95133538, filed on Sep. 11, 2006, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Field of Invention 
     The present invention relates to a heat dissipation device. 
     2. Description of Related Art 
     As the information technology and computer industry advances, portable electronic apparatuses, such as notebook computers, and other precise instruments are more widely used. Owing to demands for convenience and practicality, the portable electronic product is designed to be lighter, thinner, shorter, and smaller. For example, a notebook PC is required to be lighter, thinner and powerful in computing performance. 
     Because of the requirement of lighter, thinner, shorter, and smaller for portable electronic apparatuses, components therein face a heat dissipation problem. The mainstream framework of heat dissipation design in a portable electronic apparatus, i.e. a notebook computer, is forced heat convection via a centrifugal fan. 
     Once heat dissipation efficiency is enhanced, airflow is essentially accelerated. The stronger the airflow is, the more turbulent the wake flow is. Thus, notebook PC manufacturers face a challenge between reducing noise and improving overall heat dissipation efficiency. 
     SUMMARY 
     A heat dissipation device includes a hollow housing and a speaker. The hollow housing has a first opening and a second opening. The speaker is disposed at the first opening, wherein the speaker includes a diaphragm oscillating within a frequency scope the human ear cannot or hardly hear so as to generate airflow through the second opening. 
     A heat dissipation device is described. A hollow housing has a first opening and a second opening. A diaphragm having a magnet is disposed at the first opening. A magnetic circuit means for oscillating the diaphragm within a frequency scope the human ear cannot or hardly hear is disposed inside the hollow housing so as to generate airflow through the second opening. 
     A method for heat dissipating is described. A hollow housing having a first opening and a second opening is provided. A speaker is disposed at the first opening. A diaphragm of the speaker is oscillated within a frequency scope the human ear cannot or hardly hear so as to generate airflow through the second opening. 
     It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings, 
         FIG. 1  illustrates a cross sectional view of a heat dissipation device according to one embodiment of this invention; and 
         FIG. 2  illustrates a cross sectional view of a heat dissipation device according to another embodiment of this invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     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. 
       FIG. 1  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 . 
       FIG. 2  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.

Technology Category: g