Droplet movement actuated by electrical voltage
The water droplets in an opaque liquid (i.e. blackened decane) are used as optical irises.
The video gives a view onto a preliminary 3x3 test iris array (standing vertically) with 2x2 different droplet/iris positions in each subarray, switched between by electrowetting-on-dielectrics (EWOD). There is diffuse illumination from the back.
Any of the droplets belongs to one 2x2 subarray and has a volume of around 60 nl. A single subarray has dimensions of 1mm x 1mm x 0.25 mm.
The rectangular AC drive voltage is 2x 130 V peak-to-peak (response time <40 ms) and has a frequency of 5 kHz.
One of the subarrays (right bottom) is not working; i. e. the droplet does not move. In another subarray (left middle) a small air bubble is visible (having entered the subarray upon packaging), of course not actuated by EWOD, but by the movement of the main droplet.