Apparatus and method for inspecting droplet

A method of inspecting a droplet on a substrate, the method comprising:

• applying, using an ultrasonic transmitter, an ultrasonic wave to a droplet on the substrate;
• detecting, using an ultrasonic receiver, an ultrasonic wave reflected from the droplet on the substrate and converting the detected ultrasonic wave to an electrical signal;
• acquiring a plurality of heights of the droplet at a plurality of positions on the substrate on the basis of the electrical signal received from the ultrasonic receiver;
• calculating a volume of the droplet on the basis of the plurality of heights of the droplet at the plurality of positions;
• and
• storing or outputting data in relation to the volume of the droplet.

An inkjet printing facility comprising:

• a substrate loading part configured to load a substrate;
• a substrate conveying part configured to convey the substrate;
• a substrate processing part comprising a support unit on which the substrate is seated, a head unit configured to discharge a droplet onto the substrate seated on the support unit, and a gantry to which the head unit is movably coupled;
• a facility inspection part configured to inspect a module comprised in the substrate processing part;
• an apparatus for inspecting the droplet discharged by the head unit, the apparatus being comprised in the substrate processing part or the facility inspection part;
• and
• a substrate unloading part configured to unload the substrate,
• wherein the apparatus for inspecting the droplet comprises:
• an ultrasonic sensor configured to apply an ultrasonic wave to the droplet from above or below the substrate, detect an ultrasonic wave reflected from the droplet on the substrate, and convert the detected ultrasonic wave to an electrical signal;
• and
• a processor configured to acquire a plurality of heights of the droplet at a plurality of positions on the substrate on the basis of the electrical signal that is received from the ultrasonic sensor, calculate a volume of the droplet on the basis of the plurality of heights of the droplet at the plurality of positions, and output or store data in relation to the volume of the droplet.