Method of Fabricating Bubble-Type Micro-Pump

Abstract

A manufacturing method of a bubble-type micro-pump is provided. At least a bubble-generating unit is provided on the bubble-generating section. Because of the varied surface energies on the top of the bubble-generating section, the varied backfilling velocities of the fluid of the front end and the rear end cause fluid moving when a bubble vanishes. The top surface of the bubble-generating section is subjected to a particular surface treatment to form a surface energy gradient. Examples of surface treatment include sputtering a thin film with varied densities or thickness, radiating one or multi-layer thin films by a laser beam, etc.

What is claimed is: 
     
         1 . A method of fabricating a bubble-type micro-pump, comprising:
 providing a micro-channel having a top surface, a bottom surface and two side walls, the micro-channel comprising at least a bubble-generating section;   providing a bubble-generating unit in the bubble-generating section of the micro-channel, for generating a bubble in a liquid between a front end and a rear end of the bubble-generating section; and   applying a surface treatment to the top surface of the bubble-generating section to form a surface energy gradient on the top surface, so that a difference between a backfilling velocity at the front end and that at the rear end drives the liquid to flow toward the front end or the rear end;   wherein the surface energy gradient is formed by using a laser beam.   
     
     
         2 . The method according to  claim 1 , wherein at least two regions with different surface energies are formed by laser technology to form the surface energy gradient on the top surface. 
     
     
         3 . The method according to  claim 2 , wherein the step of forming the surface energy gradient on the top surface comprises:
 forming a reflective layer on the top surface in the bubble-generating section;   forming a first film on the reflective layer after forming the reflective layer;   forming a second film on the first film after forming the first film;   heating a plurality of regions of the first film and the second film in the bubble-generating section by a laser beam, and the heated regions comprising complex of the first film and the second film, wherein the surface energy of the heated regions is different from that of the un-heated regions.   
     
     
         4 . The method according to  claim 3 , wherein the first film and the second film are formed by sputtering. 
     
     
         5 . The method according to  claim 2 , wherein the step of forming the surface energy gradient on the top surface comprises:
 forming a reflective layer on the top surface in the bubble-generating section;   forming a mixed film on the reflective layer after the step of forming the reflective layer; and   heating a plurality of regions of the mixed film in the bubble-generating section by a laser beam, wherein the surface energy of the heated regions is different from that of the un-heated regions.   
     
     
         6 . The method according to  claim 5 , wherein the mixed film comprises a pressure sensitive adhesive and a foaming agent, a plurality of foaming protruding parts are formed in the laser-heated regions, and the surface energy of the foaming protruding parts is different from that of the un-heated regions. 
     
     
         7 . The method according to  claim 5 , wherein the mixed film comprises a pressure sensitive adhesive and a dye, a plurality of concaves are formed in the laser-heated regions, and the surface energy of the concaves is different from that of the un-heated regions. 
     
     
         8 . The method according to  claim 2 , wherein the step of forming the surface energy gradient on the top surface comprises:
 forming a plurality of micro-cylinders on the top surface by a laser beam, the variation of the cross-sectional area of the micro-cylinders causing varied surface roughness of the top surface for forming the surface energy gradient.   
     
     
         9 . The method according to  claim 8 , wherein the step of forming a plurality of micro-cylinders on the top surface by a laser beam comprises:
 forming a first cylinder group comprising a plurality of first micro-cylinders with the same cross-sectional area; and   forming a second cylinder group comprising a plurality of second micro-cylinders with the same cross-sectional area, wherein the cross-sectional area of the first micro-cylinders is different from that of the second micro-cylinders.   
     
     
         10 . The method according to  claim 9 , wherein the step of forming a plurality of micro-cylinders on the top surface by a laser beam comprises forming a plurality of micro-cylinders with the cross-sectional area gradually increasing or decreasing from the front end to the rear end, which forms a surface energy gradient on the top surface of the bubble-generating section. 
     
     
         11 . The method according to  claim 1 , wherein the step of providing the micro-channels comprises:
 providing a first substrate and a second substrate, the first substrate comprising at least a recess having the bubble-generating section; and   attaching the first substrate and the second substrate, wherein the surface of the recess forms the top surface and the two walls of the micro-channel, and surface of the second substrate forms the bottom surface of the micro-channel.   
     
     
         12 . The method according to  claim 11 , wherein the step of providing the bubble-generating unit comprises:
 disposing a first electrode and a second electrode on the bottom surface in the bubble-generating section, the first electrode and the second electrode respectively adjacent to the front end and the rear end of the bubble-generating section.   
     
     
         13 . The method according to  claim 11 , wherein the first substrate is manufactured by a disc manufacturing process. 
     
     
         14 . The method according to  claim 11 , wherein the first substrate with the recess is manufactured by injection molding, pressure casting or etching. 
     
     
         15 . The method according to  claim 11 , wherein the first substrate and the second substrate are attached by a pressure sensitive adhesive.