Patent ID: 8201913

Claim:
A liquid handling system, comprising: a liquid supply; a drop ejector operatively connected to the liquid supply, the ejector having nozzles through which drops of liquid are ejected through a drop zone toward a drop receiver, the drop zone having a length less than or equal to 3 mm in a Z direction between the nozzles and the receiver; a movable carriage carrying the drop ejector for positioning the drop ejector relative to a drop receiver; a light source for illuminating drops of liquid passing through the drop zone; a light sensor exposed to the drop zone for sensing light from the light source scattered off drops of liquid as the drops pass through the drop zone, the light sensor supported in a substrate at least partially surrounding the ejector nozzles and having a cross sectional dimension in the Z direction less than the length of the drop zone; a photo detector operatively connected to the light sensor for converting light from the light sensor into an electrical signal; and a controller operatively connected to the drop ejector and the photo detector for selectively ejecting drops from the ejector, and to the ejector carriage for moving the ejector carriage to position the ejector relative to a drop receiver.