JP2005090986A - Liquid dispenser - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid dispenser capable of always dispensing a liquid stably. <P>SOLUTION: The liquid droplets dripped from the leading end of a piezoelectric element 2 are laterally photographed by a video camera 4 and captured by a computer 6 being a control device to be processed. The computer 6 is constituted so as to process the image of the photographed liquid droplets to determine whether or not three liquid droplets are vertically arranged at a predetermined interval. When the liquid droplets taken by the video camera 4 are vertically arranged at a predetermined interval, the same dispensing condition signal as the previous time is supplied to a drive device 8 by the computer 6. However, when the liquid droplets are not vertically arranged at a predetermined interval in the image of the taken-in liquid droplets, a new dispensing condition signal is determined by the computer 6 so that the liquid droplets are vertically arranged at a predetermined interval to be supplied to the drive device 8 which in turns emits a drive signal representing a change in dispensing condition. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a liquid dispensing apparatus, and more particularly to a liquid dispensing apparatus suitable for analysis apparatuses such as analysis, clinical, and biotechnology.

  In a conventional dispensing device, a dispensing element is driven based on a predetermined dispensing condition. However, since the droplet may not fall vertically, it is difficult to accurately dispense the liquid at the target position. Therefore, in a certain type of dispensing device, a CCD camera is attached to the side to check whether or not the droplet is dropping in a correct locus, and the state of the dropping of the droplet is visually observed. The method is taken. In this case, when the droplet does not draw a correct trajectory, the discharge condition is adjusted by manually changing the droplet discharge condition so that the droplet falls along the correct trajectory.

Even when observing the state of dispensing using a CCD camera, it is best to manually change the parameters of the dispensing control device while observing the image from the CCD camera, so that the droplet falls with a correct trajectory. It is necessary to find the conditions, and the parameters for dispensing differ depending on the liquid properties of the droplets, so it is necessary to conduct tests for each type of liquid to find the parameters for the droplets to fall along the correct trajectory. Don't be.
In addition, when dispensing a large amount of liquid droplets over a long period of time, it is necessary for a person to always monitor the state of dispensing.

  Accordingly, an object of the present invention is to provide a liquid dispensing device that eliminates the need for a person to monitor the trajectory of a droplet and adjust the dispensing conditions, and can always stably dispense a liquid to a target position. It is said.

  The present invention includes a dispensing element that drops a droplet from the tip, a driving device that drives the dispensing element by supplying a driving signal determined by a dispensing condition signal supplied from the outside to the dispensing element, An imaging means for imaging a droplet dropped from a dispensing element; and a control device that determines the dispensing condition signal based on a set dispensing condition and supplies the dispensing condition signal to the driving device. The dispensing condition signal of the dispensing element is changed so that the droplet trajectory obtained by the imaging means becomes a desired trajectory.

An example of the image pickup means is a video camera such as a CCD camera, which is provided with a strobe light source, and the strobe light emission is synchronized with the drive signal.
Another example of the image pickup means uses a high-speed camera and synchronizes the shutter with the drive signal.
A preferred example of the dispensing element is a piezo element. In that case, the drive signal for driving the dispensing element is at least one of an applied voltage value, a voltage application time, and an applied voltage rise time.

  Dispensing conditions of the dispensing element so that when the imaging device observes that the trajectory of the droplet dropped by the dispensing element deviates from the desired trajectory, the droplet is dropped in a desired trajectory Therefore, it is not necessary for a person to constantly monitor dispensing, and droplets can be stably dropped at a target position.

One embodiment will be described below.
As shown in FIG. 1, the piezo-type dispensing apparatus includes a piezo element 2 having a discharge portion at the tip. The piezo element 2 ejects liquid droplets from the ejection unit by pressing a liquid reservoir connected to the ejection unit by a driving unit equipped with the piezo element. A piezo dispensing control unit 10 is provided in order to control the driving unit to eject droplets of a certain size, and the piezo element 2 according to the piezo element driving parameters set in the piezo dispensing control unit 10. A droplet is discharged from the nozzle.
As the piezo element 2, for example, as shown in FIG. 2, the liquid reservoir 32 connected to the hole of the discharge part 30 at the tip is pressed by a drive part 34 provided with a piezo element to discharge liquid from the discharge part 30. . A pressure unit (not shown) is connected to the liquid reservoir 32 so as to maintain a constant pressure state even when the liquid in the liquid reservoir 32 decreases.

FIG. 3 is a block diagram schematically showing the configuration of the liquid dispensing apparatus of one embodiment.
The liquid dispensing apparatus includes a piezo element 2 as a liquid dispensing element for dropping a liquid, a video camera 4 as an image pickup unit for imaging a droplet dropped from the piezo element 2 from the side, and a piezo element 2. A stroboscopic illumination device 5 that irradiates the droplet with light in synchronization with the dropping of the droplet, a computer 6 that determines a dispensing condition signal for the piezo element 2, and a dispensing condition signal supplied from the computer 6 And a driving device 8 that generates a driving signal based on the above and supplies the driving signal to the piezo element 2. The piezo dispensing control unit 10 in FIG. 1 is realized by the drive device 8 and the computer 6.

  In photographing the droplet, the light emitted from the strobe lighting device 5 is synchronized with the dispensing of the piezo element 2, and the droplet irradiated by the strobe lighting device 5 is photographed by the video camera 4. If the liquid droplets irradiated onto the stroboscopic illumination device 5 and imaged by the video camera 4 are normal, the stroboscopic light emission is synchronized with the liquid droplet dropping. Several droplets (three droplets in the same embodiment) are photographed vertically aligned at predetermined intervals. When the parameters for dispensing by the piezo element 2 are not appropriate, the droplets photographed by the video camera 4 are not aligned vertically or are not aligned at a predetermined interval.

  The computer 6 determines a dispensing condition signal based on the dispensing condition input by the operator and supplies it to the drive device 8. The drive device 8 generates a drive signal such as an analog waveform shown by a solid line in FIG. 4 based on the dispensing condition signal from the computer 6, and the drive signal is supplied to the piezo element 2. The piezo element 2 dispenses liquid based on the drive signal. An image of the dropped liquid droplet is captured by the video camera 4 and captured by the computer 6. The computer 6 processes the photographed droplet image and determines whether or not the droplets are arranged vertically at a predetermined interval.

  When the droplets captured by the video camera 4 are arranged vertically at a predetermined interval, the same dispensing condition signal as that of the previous time is supplied from the computer 6 to the driving device 8. However, in the case where the droplets are not arranged vertically at a predetermined interval in the captured droplet image, the computer 6 determines a new dispensing condition signal and supplies it to the driving device 8, and the driving device 8 in FIG. A drive signal having a changed dispensing condition such as an analog waveform indicated by a broken line is generated. Even after changing the dispensing conditions, the image of the droplet dropped from the piezo element 2 is photographed by the video camera 4 to check the locus of the dropped droplet. If the droplet is not dropped correctly, the dispensing condition is changed. And make sure that dispensing is done correctly. By always performing this operation, the liquid can be dispensed automatically and stably without being monitored by a person for a long time.

The dispensing condition signal is set based on the result obtained by processing the image obtained by the video camera 4 except for the first droplet generation.
Dispensing parameters of the piezo element 2 are applied voltage value, voltage application time, applied voltage rise time, and the like.

FIG. 5 is a flowchart showing the operation of the embodiment.
When the operator inputs a desired dispensing condition to the computer 6, a dispensing condition signal corresponding to the dispensing condition is supplied from the computer 6 to the driving device 8, and the driving device 8 drives the driving signal based on the dispensing condition signal. Is supplied to the piezo element 2. The piezo element 2 dispenses droplets according to the drive signal supplied from the drive device 8, and the droplet image is taken by the video camera 4. The computer 6 takes in the image of the photographed droplet and determines whether or not the dispensing is correctly performed. If the dispensing is not performed correctly, the computer 6 changes the parameters of the piezo element. Even after changing the parameter, the image of the droplet is captured, and if there is a problem with the locus of the droplet, the parameter is changed again. If it is determined that the dispensing is correctly performed, the same dispensing condition signal as the previous time is supplied to the driving device 8, and the same dispensing is performed. Until the predetermined dispensing operation is completed, the trajectory of the droplet is always checked, and if the droplet is not correctly dropped vertically, control is performed to correct it.

As described above, by observing the droplet trajectory with a video camera at all times and performing feedback control to correct the droplet trajectory to the correct trajectory, a large amount of liquid is dispensed over a long period of time. However, it is not necessary for the person to monitor, and the liquid can be dispensed stably.
Moreover, it can apply similarly even if it replaces with a piezoelectric element as a dispensing element, for example, is a case where an inkjet element etc. are used.
The image of the droplet trajectory can be performed by a high-speed camera as shown in FIG. 6 instead of the video camera 4. In that case, it is preferable to synchronize the opening timing of the shutter of the high-speed camera with the dispensing operation of the dispensing element.

It is the schematic which shows a piezo-type dispensing apparatus. It is a longitudinal cross-sectional view which shows the structure of a piezoelectric element. It is a block diagram which shows one Example schematically. It is a graph which shows a drive signal. It is a flowchart figure which shows the operation | movement of the Example. It is a block diagram of the liquid dispensing apparatus at the time of imaging | photography of a droplet using a high-speed camera.

Explanation of symbols

2 Piezo element 4 Video camera 5 Strobe lighting 6 Computer 8 Drive unit

Claims (5)

A dispensing element for dropping a droplet from the tip;
A driving device for driving the dispensing element by supplying a driving signal determined by a dispensing condition signal supplied from the outside to the dispensing element;
Imaging means for imaging a droplet dropped from the dispensing element;
A controller that determines the dispensing condition signal based on the set dispensing condition and supplies the signal to the drive device,
The liquid dispensing apparatus according to claim 1, wherein the control device changes the dispensing condition signal of the dispensing element so that a droplet trajectory obtained by the imaging unit becomes a desired locus.   The liquid dispensing apparatus according to claim 1, wherein the image pickup unit includes a strobe light source, and synchronizes strobe light emission with the drive signal.   The liquid dispensing apparatus according to claim 1, wherein the imaging unit is a high-speed camera, and synchronizes a shutter with the drive signal.   The liquid dispensing apparatus according to claim 1, wherein the dispensing element is a piezo element.   The liquid dispensing apparatus according to claim 4, wherein the drive signal is at least one of an applied voltage value, a voltage application time, and an applied voltage rise time.

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