This invention offers a liquid crystal display device according to FFS technology. The electromagnetic radiation is collectively emitted by an array defining a layer aligned parallel with the surface and overlapping at least a region of the surface onto which the graphical user interface is projected. The ultrasonic receiver receives a synchronous echo, and determines whether the amplitude of the synchronous echo is larger than a first threshold. The chips can efficiently be discharged from the tool without being deposited in the internal fluid passage, by the air which flows at a suitable speed through the internal fluid passage and draws the chips, regardless of the diameter of the tool.