The present invention relates generally to techniques that sense thermal stimuli. In particular, implementations employ arrays of cells, each including thermometer elements or other thermal sensors. Such arrays can be used, for example, in a calorimeter, a term used herein to refer to any device or apparatus that measures quantities of absorbed or evolved heat or determines specific heats; the use of a calorimeter is referred to herein as calorimetry.
Calorimetry can measure enthalpic changes, including enthalpic changes arising from reactions, phase changes, changes in molecular conformation, temperature variations, and other variations of interest that may occur for a particular specimen. By measuring enthalpic changes over a series of conditions, other thermodynamic variables may be deduced. For example, measurements of enthalpy as a function of temperature reveal the heat capacity of a specimen, and titrations of reacting components can be used to deduce the binding constant and effective stoichiometry for a reaction.
Arrays have been proposed for performing calorimetry. U.S. patent application Publication Nos. 2004/0038227 and 2004/0038228 describe array devices for high-throughput lead profiling and microphysiometry, respectively.
Arrays of cells with thermometer elements or other thermal sensors can also be used in other applications. For example, U.S. Pat. No. 6,701,774 describes a parallel gas chromatograph with a microdetector array. Each microdetector is a thermal conductivity detector with one or more thin-film detection filaments.
Previous techniques in sensing or detecting heat or temperature in cells of an array have a number of limitations. It would be advantageous to have additional techniques for cells with thermometer elements or other thermal sensors. In particular, it would be advantageous to have techniques that could be used in very sensitive calorimetry.