Liquid dispensing apparatus, coating apparatus for same, and liquid dispensing method

A liquid dispensing apparatus that sucks a liquid into a measuring bore and ejects the liquid in the measuring bore by moving a piston reciprocally, the liquid dispensing apparatus comprising:

• a liquid contact member that has first and second measuring bores;
• a first piston sliding in the first measuring bore in close contact therewith and a second piston sliding in the second measuring bore in close contact therewith;
• a supply channel communicating with a storage unit;
• an ejection channel communicating with a nozzle;
• a switching valve that is disposed in an inner space of the liquid contact member, and that has a first position at which the first measuring bore is communicated with the supply channel and the second measuring bore is communicated with the ejection channel, and a second position at which the first measuring bore is communicated with the ejection channel and the second measuring bore is communicated with the supply channel;
• a valve driving mechanism that operates the switching valve;
• and
• a piston driving mechanism that operates an arm connected to the first and second pistons,
• wherein the first and second measuring bores are arranged to oppose to each other on both sides of the switching valve, and
• the supply channel and the ejection channel are arranged adjacent to the switching valve, and
• wherein the liquid contact member includes a first bubble mixing prevention mechanism including a first bore that is communicated with the first measuring bore and that allows the piston to move reciprocally in the first bore, and a second bore that is communicated with the first bore at a lateral surface thereof, and a second bubble mixing prevention mechanism including a first bore that is communicated with the second measuring bore and that allows the piston to move reciprocally in the first bore, and a second bore that is communicated with the first bore at a lateral surface thereof.

A coating apparatus comprising:

• a liquid dispensing apparatus that sucks a liquid into a measuring bore and ejects the liquid in the measuring bore by moving a piston reciprocally;
• a compressed gas source that supplies compressed gas to apply pressure to a liquid that is stored in a storage vessel;
• a discharge controller that controls the valve and piston driving mechanisms of the liquid dispensing apparatus and gas pressure in the compressed gas source;
• a work table on which a coating target is placed;
• XYZ driving mechanisms that move the liquid dispensing apparatus and the work table relative to each other;
• and
• a driving controller that controls operations of the XYZ driving mechanisms,
• wherein the liquid dispensing apparatus comprising:
• a liquid contact member that has first and second measuring bores;
• a first piston sliding in the first measuring bore in close contact therewith and a second piston sliding in the second measuring bore in close contact therewith;
• a supply channel communicating with a storage unit;
• an ejection channel communicating with a nozzle;
• a switching valve that is disposed in an inner space of the liquid contact member, and that has a first position at which the first measuring bore is communicated with the supply channel and the second measuring bore is communicated with the ejection channel, and a second position at which the first measuring bore is communicated with the ejection channel and the second measuring bore is communicated with the supply channel;
• a valve driving mechanism that operates the switching valve;
• and
• a piston driving mechanism that operates an arm connected to the first and second pistons,
• wherein the first and second measuring bores are arranged to oppose to each other on both sides of the switching valve, and
• the supply channel and the ejection channel are arranged adjacent to the switching valve, and
• wherein the arm holds constant a distance between the first and second pistons.