A solid-state imaging device including a first transfer electrode portion and a second transfer electrode portion having a pattern area ratio higher than that of the first transfer electrode portion. The inner roof frame can include, at least in part, an elongated, transversely extending, intermediate roof rail having a first material thickness, and a plurality of reinforced roof rails. A number of assay pad constructions are described which may include at least one or more of the following components: a prefilter component, a reflective component, a membrane component, a reagent component, a mesh component, and a component to prevent lateral spreading. Furthermore, the circuit is easy to implement and the calibrating process can be easily performed.