Size measurement of microdroplets using light scattering
1Current Research – Size measurements of microdroplets using light scattering
Evaluation of droplet size in inkjet systems is necessary for…• Printing technology• Manufacturing “functional droplets”
(→refer to “Dynamics of colliding microdroplets”)
Inkjets
10µm in radius 10m/s in velocity 100,000
droplets/sec
Measuring such a small yet fast particles requires special skills
2Current Research – Size measurements of microdroplets using light scattering
Previous methodsMicroscopic Picture Flow Rate Method
Disadvantage;Intrinsic error of about a wavelength resides at the interface
~10µm Counting the amount of
time it takes to produce certain amount of droplets
Disadvantage;Takes a long time.Cannot measure directly; inapplicable to size-changing phenomena
3Current Research – Size measurements of microdroplets using light scattering
Light ScatteringRayleigh Scattering ( Particles smaller than the wavelength )
Mie Scattering ( Particles larger than the wavelength )
large
small
The interference pattern changes with size
4Current Research – Size measurements of microdroplets using light scattering
He-Ne Laser
Lens
CCD
Experiment
Theoretical analysis of the interference position led to a simple method enabling size measurement with 0.3% error.
Techniques and skills• IT
Microsoft Office Suite, gnuplot, ImageJ• Programming
Java• Techniques
Light scattering, image processing, etc.• Equipment
Oscilloscope, function generator, etc.
5Current Research – Size measurements of microdroplets using light scattering