Circuit board adapted to fan and fan structure

Abstract

A circuit board adapted to a fan comprises a circuit region and a heat-dissipative film. The circuit region is provided on a first surface of the circuit board and comprises at least one heat-generating component thereon. The heat-dissipative film is coated on an edge portion of the first surface and is in contact with the heat-generating component. A plurality of openings through the heat-dissipative film, a protrusion of the circuit board, a cutout in the protrusion to expose the heat-generating component to airflow, etc., have been disclosed and claimed for enhancing the efficiency in heat dissipation. A heat sink may also be provided on a second surface opposite to the first surface of the circuit board. The heat sink is connected to the heat-dissipative film to help dissipate the heat generated by the operation of the fan.

What is claimed is:  
     
         1 . A fan structure comprising a hub, a motor located inside the hub, a plurality of fan blades connected to the hub, and a circuit board connected to the motor, wherein the circuit board comprises: 
 a circuit region provided on a first surface of the circuit board, the circuit region comprising at least one heat-generating component thereon; and    a heat-dissipative film coated on an edge portion of the first surface and in contact with the heat-generating component.    
     
     
         2 . The fan structure as claimed in  claim 1 , wherein the circuit region is surrounded by the heat-dissipative film.  
     
     
         3 . The fan structure as claimed in  claim 1 , wherein the heat-dissipative film extends outside the circumference of the hub.  
     
     
         4 . The fan structure as claimed in  claim 1 , wherein the heat-dissipative film is formed with a plurality of openings.  
     
     
         5 . The fan structure as claimed in  claim 1 , further comprising a heat sink located on a second surface of the circuit board opposite to the first surface of the circuit board.  
     
     
         6 . The fan structure as claimed in  claim 5 , wherein the heat sink is connected to the heat-dissipative film by means of a plurality of through holes and a fastening portion.  
     
     
         7 . The fan structure as claimed in  claim 1 , wherein the first surface of the circuit board comprises a protrusion for carrying the heat-generating component and optionally the heat-dissipative film, and the protrusion extends outside the circumference of the hub.  
     
     
         8 . The fan structure as claimed in  claim 7 , wherein the protrusion has a cutout that extends from a tip of the protrusion to the heat-generating component.  
     
     
         9 . The fan structure as claimed in  claim 7 , wherein the protrusion has a cutout that extends over a portion of the heat-generating component so that the portion of the heat-generating component is exposed via the cutout in the protrusion.  
     
     
         10 . A fan structure comprising a hub, a motor located inside the hub, a plurality of fan blades connected to the hub, and a circuit board connected to the motor, wherein the circuit board comprises a protrusion, which extends outside the circumference of the hub and carries thereon a heat-generating component.  
     
     
         11 . The fan structure as claimed in  claim 10 , wherein the protrusion further comprises a cutout that extends from a tip of the protrusion to the heat-generating component.  
     
     
         12 . A circuit board for operating a fan, comprising: 
 a circuit region provided on a first surface of the circuit board and including at least one heat-generating component thereon; and    a heat-dissipative film coated on an edge portion of the first surface and in contact with the heat-generating component.    
     
     
         13 . The circuit board as claimed in  claim 12 , wherein the circuit region is surrounded by the heat-dissipative film.  
     
     
         14 . The circuit board as claimed in  claim 12 , wherein the heat-dissipative film is formed with a plurality of openings.  
     
     
         15 . The circuit board as claimed in  claim 12 , further comprising a heat sink provided on a second surface of the circuit board opposite to the first surface of the circuit board.  
     
     
         16 . The circuit board as claimed in  claim 15 , wherein the heat sink is connected to the heat-dissipative film by means of a plurality of through holes and a fastening portion.  
     
     
         17 . The circuit board as claimed in  claim 15 , wherein the heat sink is selected from the group consisting of a heat-conducting film and a heat-conducting sheet.  
     
     
         18 . The circuit board as claimed in  claim 12 , wherein the first surface of the circuit board comprises a protrusion and the at least one heat-generating component is mounted over the protrusion of the first surface.  
     
     
         19 . The circuit board as claimed in  claim 17 , wherein the protrusion has a cutout that extends from a tip of the protrusion to the heat-generating component and optionally to the heat-dissipative film.  
     
     
         20 . The circuit board as claimed in  claim 12 , wherein the heat-dissipative film is formed by a coating film made of heat-conducting material.