Heat exchanger

Abstract

A heat exchanger ( 1 ) includes: a heat sink ( 3 ) which is in contact with a heating element ( 2 ); and an electron emitting element ( 4 ) which is provided so as to be separated from the heat sink ( 3 ) by a space and which provides electrons to the heat sink ( 3 ) via air in the space. The electron emitting element ( 4 ) includes: an electrode substrate ( 7 ); a thin-film electrode ( 9 ); a power supply ( 10 ) which applies a voltage between the electrode substrate ( 7 ) and the thin-film electrode ( 8 ); and an electron acceleration layer ( 8 ) which accelerates the electrons inside itself in response to the voltage applied by the power supply ( 10 ) so that the electrons are emitted from the thin-film electrode ( 9 ). The electron acceleration layer ( 8 ) is made at least partially of an insulating material. As a result, the heat exchanger ( 1 ) has a heat exchange capability which can be maintained and improved independently of a structure in which electric field concentration tends to occur.

1 . A heat exchanger, comprising:
 a contact member which is electrically conductive and which is for contacting with a target of heat exchange; and   an electron emitting element which is provided so as to be separated from the contact member by a space and which provides electrons to the contact member via air in the space,   the electron emitting element including:   an electrode substrate; a thin-film electrode;   first voltage applying means for applying a voltage between the electrode substrate and the thin-film electrode; and   an electron acceleration layer which accelerates electrons inside itself by the voltage applied from the first voltage applying means so that the electrons thus accelerated are emitted from the thin-film electrode,   the electron acceleration layer being formed at least partially from an insulating material.   
     
     
         2 . The heat exchanger according to  claim 1 , wherein the electron acceleration layer includes:
 conductive particles formed from an electric conductive material and surrounded by a first dielectric material; and   a second dielectric material larger than the conductive particles.   
     
     
         3 . The heat exchanger according to  claim 2 , wherein the electric conductive material, from which the conductive particle is formed, includes at least one of gold, silver, platinum, nickel, and palladium. 
     
     
         4 . The heat exchanger according to  claim 2 , wherein the first dielectric material includes at least one of alcoholate, aliphatic acid, and alkanethiol. 
     
     
         5 . The heat exchanger according to  claim 2 , wherein the second dielectric material includes either at least one of SiO 2 , Al 2 O 3 , and TiO 2 , or an organic polymer. 
     
     
         6 . The heat exchanger according to  claim 1 , wherein the thin-film electrode includes at least one of gold, carbon, nickel, titanium, and aluminum. 
     
     
         7 . The heat exchanger according to  claim 2 ,
 wherein:
 the first dielectric material is a coating material for coating the conductive particle; 
 the coating material has a thickness smaller than an average diameter of the conductive particles; 
 the second dielectric material takes a form of particles having an average diameter larger than the average diameter of the conductive particles, coated dielectrically with the coating material. 
   
     
     
         8 . The heat exchanger according to  claim 2 ,
 wherein:
 the first dielectric material is a coating material for coating the conductive particle; 
 the coating material has a thickness smaller than an average diameter of the conductive particles; 
 the second dielectric material takes a form of a sheet, and is placed on the electrode substrate; 
 the second dielectric material has a plurality of openings which penetrate the second dielectric material in a thickness direction; and 
 the openings contain the conductive particles, which are dielectrically coated with the coating material. 
   
     
     
         9 . The heat exchanger according to  claim 7 , wherein the particles of the second dielectric material have an average diameter which falls within a range from 30 nm to 1000 nm. 
     
     
         10 . The heat exchanger according to  claim 7 , wherein the conductive particles, which are dielectrically coated, have an average diameter of 10 nm or smaller. 
     
     
         11 . The heat exchanger according to  claim 2 , wherein the second dielectric material accounts for 80 w % to 95 w % of the electron acceleration layer. 
     
     
         12 . The heat exchanger according to  claim 2 , wherein the electron acceleration layer has a thickness which falls within a range from 30 nm to 1000 nm. 
     
     
         13 . The heat exchanger according to  claim 1 , wherein the heat exchanger is a cooling device for cooling a heating element as the target of heat exchange. 
     
     
         14 . The heat exchanger according to  claim 1 , wherein the contact member is a heat sink having an up-and-down surface which faces the electron emitting element. 
     
     
         15 . The heat exchanger according to  claim 1 , wherein the electron emitting element is configured to generate a gas flow under an atmospheric pressure. 
     
     
         16 . The heat exchanger according to  claim 1 , further comprising:
 a substrate having a plane surface or a rounded surface,   wherein the electron emitting element is formed on the substrate.   
     
     
         17 . The heat exchanger according to  claim 1 , wherein the electron emitting element is flexible. 
     
     
         18 . The heat exchanger according to  claim 1 , further comprising:
 a rotary-blade airflow generator which includes a blade provided so as to face the contact member and which rotates the blade so as to blow air toward the contact member,   wherein the electron emitting element is provided on a surface of the blade which surface faces the contact member.   
     
     
         19 . The heat exchanger according to  claim 1 , wherein the electron emitting element takes a form of a mash. 
     
     
         20 . The heat exchanger according to  claim 1 , further comprising:
 second voltage applying means for applying a voltage between the contact member and the electron emitting element,   wherein the voltage applied by the second voltage applying means is higher than 0 V and not higher than +10 kV.   
     
     
         21 . The heat exchanger according to  claim 20 , wherein a strength of an electric field generated between the contact member and the electron emitting element falls within a range from 1 V/m to 10 7  V/m. 
     
     
         22 . The heat exchanger according to  claim 1 , wherein the contact member is grounded. 
     
     
         23 . The heat exchanger according to  claim 1 , wherein the contact member is provided to make an angle with an electron emission surface of the thin-film electrode of the electron emitting element, the angle falling within a range from 0° to 90°. 
     
     
         24 . The heat exchanger according to  claim 1 , wherein the contact member is separated from the electron emitting element by a distance which falls within a range from 100 pm to 50 cm.