Microtiter well plates are commonly used in immunology research and clinical diagnostic testing laboratories. The number of wells or vials in each plate vary from having 6, 12, 24, 96, 384, or 1536 wells. These vials are deep in height but narrow in width, making the process for volume measurement in the vial difficult. Each well is clear, small, narrow, and has a curved cone-shaped base, in which the volume of the liquid inside is difficult to measure.

With the use of SICK's Optical Displacement Sensor and a custom build vial positioning device, we were able to measure the volume of liquid in each vial. Traditional sensors are unable to receive a signal since the walls of the vial are too narrow and cause a disturbance to the reflected laser field. Volume measurement is made possible because the emitter and receiver are positioned to allow for narrow space measurements. The vial is first calibrated to make the liquid level known, whether it is higher or lower than the cone-shaped base. The emitted laser is positioned to be exactly at the bottom center of the vial, which is critical to have an accurate volume reading. The light can be reflected in several different directions since the bottom of the vial is curved, but engineers at Cyth were able to come up with a mechanism that accurately determined the bottom of each vial.

Since the volume of one vile can be determined, the same mechanism can be used throughout the well plate and the volume of all vials can be determined within seconds. This would save researchers and medical laboratories much more time when evaluating test tube or well plate samples. Often times, there is a minimum volume necessary for analysis of a sample in research and development applications. Other times, the volume of a sample needs to be known in order to calculate the density or other fluid properties of a specimen.