Abstract: The liquid droplet spray device (1) comprises a housing formed of a superposition of a first and a second substrate (5, 6) and a space (2) within the housing for containing a liquid substance (3), vibrating means (8) for applying a frequency vibration to the substance (3) thereby generating the liquid droplet spray, and outlet means (7, 9, 10) for ejecting the liquid droplet spray. The outlet means comprise a cavity (7), output nozzles (9) and output channels (10) connecting the cavity (7) to the outlet nozzles (9). According to the invention, the vibrating means (8) creates a standing wave pattern within the liquid substance (3), and the outlet means are arranged such that said outlet nozzles (9) are superposed on the vibration mode peaks of the standing wave pattern. Advantageously, the first and second substrates have similar geometrical shapes. Minimal retention and optimal flow of the substance are obtained.

Abstract: The liquid droplet spray device (5) has a micromachined substrate (8, 18, 18a; 8a, 18, 18a), a space (9) within the substrate for containing a liquid substance (4), an inlet channel for supplying (7) the liquid (4) to the space (9), and outlet structure (13, 14, 15) for ejecting the liquid as a mono-dispersive droplet spray when the liquid undergoes a vibration. The outlet structure comprises a cut-off pyramid-shaped tapered cavity (13) which is micromachined in the space (9). The outlet structure further comprises at least one output (14) and output channel (15) connecting the tapered cavity (13) to the outlet (14), the outlet (14) and the output channel (15) having a non-tapered vertical shape. Thanks to such a device, the exact amount ejected may be determined accurately which allows for a predicted lung deposition of the droplets by using appropriate control means adapted to the kind of patient.

Abstract: This process consists of machining a silicon piece (4) by means of selective oxidation operations and photolithography to form therein at least one cavity (7, 12) adapted to contain or convey a fluid, and of oxidizing the wall of the cavity to make this hydrophilic. The device is completed by fixing closing plates (1, 5) to its body thus formed. Prior to the machining operations the surfaces of the piece (4) adapted to be in contact with the closing plates (1, 5) are covered with a screening layer that resists these machining operations. Then, after these have been completed, the surfaces of the piece intended to be exposed to the fluid are oxidized to form therein an oxide layer favoring the wettability of these surfaces. The screening layer is then removed and the closing plates are fixed to the piece.The invention has applications, notably in micropumps.