This disclosure provides systems, methods and apparatus for preventing particles from entering electromechanical systems (EMS) display devices. In one aspect, an apparatus includes a plate, a substrate supporting at least one EMS device, a seal joining the plate and the substrate to define a cavity therebetween and at least one port for receiving a fluid, and a filter disposed between the port and the EMS device. The filter includes elements formed on at least one of a surface of the substrate and a surface of the plate, defining a gap sized to allow the received fluid to pass and to inhibit non-fluidic particles carried in the fluid from the EMS device.