Two-dimensional spectral imaging system

Abstract

Improved devices, systems, and methods for sensing and/or identifying signals from within a signal detection region are well-suited for identification of spectral codes. Large numbers of independently identifiable spectral codes can be generated by quite small bodies, and a plurality of such bodies or probes may be present within a detection region. Simultaneously imaging of identifiable spectra from throughout the detection region allows the probes to be identified. As the identifiable spectra can be treated as being generated from a point source within a much larger detection field, a prism, diffractive grading, holographic transmissive grading, or the like can spectrally disperse the images of the labels across a sensor surface. A CCD can identify the relative wavelengths of signals making up the spectra. Absolute signal wavelengths may be identified by determining positions of the labels, by an internal wavelength reference within the spectra, or the like.

What is claimed is:  
     
         1 . A method for identifying signals of differing strengths, the method comprising: 
 generating a plurality of signals in response to excitation energy, the signals comprising higher intensity signals and lower intensity signals;    sensing the lower intensity signals by simultaneously imaging the signals on a sensor; and    sequentially sensing at least some of the higher intensity signals.    
     
     
         2 . The method of  claim 1 , wherein at least one of the signals is generated by a semiconductor nanocrystal.  
     
     
         3 . The method of  claim 1 , wherein sensing the lower intensity signals comprises imaging for a first integration time, and wherein sequentially sensing the higher intensity signals comprises sequentially imaging for a second integration time shorter than the first integration time.  
     
     
         4 . The method of  claim 1 , further comprising filtering the higher intensity signals from the simultaneously imaged signals.  
     
     
         5 . The method of  claim 4 , wherein the higher intensity signals have wavelengths that are different than wavelengths of the lower intensity signals, and wherein the filtering step comprises wavelength filtering the higher intensity signals.  
     
     
         6 . The method of  claim 1 , wherein the higher intensity signals are sequentially sensed by scanning markers generating the signals, and wherein the markers generating the higher intensity signals are spatially intermingled with the markers generating the lower intensity signals.  
     
     
         7 . The method of  claim 6 , wherein the scanning step comprises scanning an aperture relative to the markers.  
     
     
         8 . The method of  claim 7 , wherein the scanning step comprises scanning a slit relative to the markers.  
     
     
         9 . The method of  claim 1 , wherein the excitation energy comprises a first energy, the first energy exciting high-energy markers to generate the high energy signals, and a second energy, the second energy exciting low-energy markers to generate the lower energy signals.  
     
     
         10 . The method of  claim 9 , wherein the second energy is less than the first energy, and wherein the second energy selectively excites the low energy markers.  
     
     
         11 . The method of  claim 1 , wherein the high intensity signals are generated by label markers and define an identifiable spectral code, and wherein the low intensity signals are generated by assay markers and indicate results of a plurality of assays, each assay having an associated spectral code.  
     
     
         12 . The method of  claim 11 , wherein the markers are supported by probe bodies to define probes, each probe comprising a label with at least one label marker to generate the spectral code, wherein at least one assay marker is associated with the probe to indicate results of an associated assay, and further comprising determining each assay result by identifying each label and correlating the label with the associated marker signal.