Abstract:
The present invention relates to an apparatus and process for producing a thin organic film on a substrate using an ultrasonic nozzle to produce a cloud of micro-droplets in a vacuum chamber. The micro-droplets move turbulently within the vacuum chamber, isotropically impacting and adhering to the surface of the substrate. The resulting product has a smooth, continuous, conformal, and uniform organic thin film, when the critical process parameters of micro-droplet size, shot size, vacuum chamber pressure, and timing are well-controlled, and defects such as nullorange peelnull effect and webbing are avoided. The apparatus includes an improved ultrasonic nozzle assembly that comprises vacuum sealing and a separate, independent passageway for introducing a directed purging gas.
Abstract:
An ultrasonic aerosol apparatus having a piezoelectric element which generates ultrasonic signals in response to signals received from an oscillating circuit, where the temperature of the piezoelectric element is controlled by an electronic device such as an N.T.C. thermistor. The temperature control device senses the temperature of the piezoelectric element and controls the power fed to the oscillator circuit in accordance with the temperature of the piezoelectric element. Rather than cut power completely to the oscillator circuit (thereby interrupting the atomization process of the apparatus), the temperature control device reduces power fed to the oscillator circuit when the piezoelectric element temperature rises above a predetermined value, and increases power fed to the oscillator circuit when the piezoelectric element temperature falls below a predetermined value. Leakage of liquids (e.g., water or medication) contained within the apparatus is avoided by the lack of joints in the liquid-holding apparatus containers. The piezoelectric element may be ceramic, and may be supported by an elastic element which itself may act as an electrical connection between the piezoelectric element and the temperature control device.
Abstract:
A method for driving an ultrasonic transducer, intended for use in atomization of liquids, at one of its selected resonance frequencies, by tuning out the capacitance of the ultrasonic transducer by means of an inductor, by sensing the transducer current, by comparing the phases of the transducer driving voltage and the transducer current and by controlling a voltage controlled oscillator for driving the ultrasonic transducer, by means of a phase error signal such that the ultrasonic transducer is driven with a frequency at which the transducer driving voltage and the transducer current are in phase, whereby the transducer driving circuit is locked to a natural resonance frequency of the ultrasonic transducer.
Abstract:
In a process and a circuit for exciting an ultrasonic generator the latter is excited by an output signal of a voltage-controlled oscillator, which is controlled by a control device including a triangular wave generator so that its frequency is periodically swept in a range covering the series resonance of the ultrasonic generator. A measured quantity value, which can be voltage or current corresponding to the damping of the ultrasonic generator, is formed and is compared with the maximum permitted damping. If the established damping is smaller than the maximum permitted damping, the oscillator is additionally regulated as a function of the measured quantity. This measured quantity is preferably a function of the exciting current of the ultrasonic generator. An instantaneous measured value and a delayed value are formed and their difference is compared with a threshold value in a comparator. If this difference is the same as the threshold value, the sweep direction in the control device is reversed. The power at the ultrasonic generator can be regulated by varying the operating voltage of an output stage connected upstream of the ultrasonic generator. The process can be used for atomizing a liquid by an ultrasonic generator provided with an atomizer disk.
Abstract:
A piezoelectric fluid atomizer comprises an oscillating plate which is made to resonate by means of an electric alternating voltage. The element causing the oscillations is a piezoceramic converter which is connected to the oscillating plate via a cylindrical extension part. The cylindrical extension with the oscillating plate is constructed as an axial extension of the front side of a bolt which comprises a widened portion in the form of an abutment plate adjacent the cylindrical extension. The bolt supports converter elements which are shaped as rings and which are pressed across the bolt against the abutment plate by means of a pressure plate. A shield which extends across the converter elements is secured on the bolt at some distance behind the pressure plate. In operation an oscillation node is present for the freely suspended part supporting the piezoelectric converter elements, at the area of the abutment plate. A further oscillation node is present for the freely supported part and the shield, at the area where the shield is secured to the bolt.
Abstract:
An ultrasonic oscillator, which can be mounted on a vehicle and which enables an oscillating element itself to generate a high ultrasonic energy, comprising a storage battery having one power line thereof grounded, a DC -- DC converter which is electrically isolated from said power lines of the storage battery and which supplies D.C. power to non-grounded power lines thereof, and a Darlington transistor circuit having a ultrasonic oscillating element connected across base and collector thereof.
Abstract:
A compact apparatus for atomisation of fluid samples comprises a sonotrode (11), placed so that an ultrasonic wave emitted by the sonotrode is directed through a channel (25) in a separate channel device (21) and reflected by from the interface (26) in a high-low impedance transition zone (Tz), so that a standing wave is formed within the channel. A positive air flow through the channel, driven by a pressure differential at each end of the channel, interacts with the working fluid or slurry being delivered by a fluid delivery device (30) to atomise it. The speed of the air flow and the dispersal, homogeneity, and size of particles in the slurry sample can be controlled by varying the shape of the channel outlet.
Abstract:
The invention relates to a method for detecting insufficient liquid in an ultrasound spraying device (1), the device (1) comprising at least one piezoelectric element (8) capable of spraying a liquid, the method being characterised in that it comprises: a step of provisionally supplying power to the piezoelectric element (8), so as to cause a deformation of the piezoelectric element (8); a step of measuring the electric current produced by the piezoelectric element (8) under the deformation thereof; and a step of comparing said current with a predetermined threshold value, insufficient liquid being detected in the spraying device (1) if said current is lower than said threshold value.