Patent ID: 6878341

Claim:
A microplate apparatus comprising: a microtiter plate defining an array of sample wells, each having exterior wall surfaces; a plate-handling machine having a plate-support surface and a sample-handling or reading device which operates on individual wells in said microtiter plate; a control unit for controlling the position of said device with respect to defined coordinates on said plate-support surface; and a locator structure comprising at least one projection extending from said plate-support surface, wherein each of said at least one projection engages said exterior wall surfaces of at least one but no more than four adjacent wells, when said microtiter plate is positioned on said plate-support surface, to fix the position of each well at a known location with respect to said defined coordinates, wherein one or more of said at least one projection and said exterior wall surfaces of one or more wells have complementary shaped regions, with said engaging taking place between said at least one projection and said complementary shaped regions of said wells when said microtiter plate is positioned on said plate-support surface.