Light detection device

Abstract

Apparatus and methods for optical detection with improved read speed and/or signal-to-noise ratio.

We claim:  
     
         1 . An apparatus for detecting light transmitted from a substrate having a plurality of sample sites, the apparatus comprising: 
 a stage for supporting the substrate, the stage being configured to move the substrate in a first direction so that the sample sites pass sequentially through an examination region delimited by a detection initiation position and a detection termination position;    a detector configured to detect light;    an optical relay structure configured to transmit light from a sensed volume within the examination region to the detector, the sensed volume being smaller than the examination region; and    an automated scanning mechanism configured to move the sensed volume in the first direction between the detection initiation position and the detection termination position;    wherein the sensed volume tracks a first sample site as it moves between the initiation position and the termination position, so that light transmitted by the first sample can be detected by the detector.    
     
     
         2 . The apparatus of  claim 1 , wherein the sensed volume returns to the initiation position after the first sample site passes the termination position to track the next sample site as it moves between the initiation position and the termination position.  
     
     
         3 . The apparatus of  claim 1  further comprising a light source, where the optical relay structure further is configured to transmit light from the light source to the sensed volume.  
     
     
         4 . The apparatus of  claim 1 , wherein the sample sites move at a substantially constant speed through the examination region.  
     
     
         5 . The apparatus of  claim 1 , wherein the time required for the sensed volume to return to the initiation position is less than the time required for the sensed volume to track a sample site as it moves between the initiation position and the termination position.  
     
     
         6 . The apparatus of  claim 1 , wherein the scanning mechanism includes reflective optics.  
     
     
         7 . The apparatus of  claim 6 , wherein the reflective optics is selected from the group consisting of a parabolic mirror, a polygonal mirror, and a galvanometer mirror.  
     
     
         8 . The apparatus of  claim 6 , wherein at least a portion of the reflective optics undergoes translational motion to track the sample sites.  
     
     
         9 . The apparatus of  claim 6 , wherein at least a portion of the reflective optics undergoes rotational motion to track the sample sites.  
     
     
         10 . The apparatus of  claim 1 , wherein the scanning mechanism includes refractive optics.  
     
     
         11 . The apparatus of  claim 6 , wherein the detector includes a wide area detection device, and the scanning mechanism includes a light blocking member having an aperture positioned between the detection device and the examination region so that sensed volume tracking through the examination region is facilitated by moving the light blocking member relative to the wide area detection device.  
     
     
         12 . The apparatus of  claim 1 , wherein the substrate is selected from the group consisting of a microplate, a biochip, and a chromatography plate.  
     
     
         13 . The apparatus of  claim 12 , wherein the substrate is a microplate and the sample sites are wells in the microplate.  
     
     
         14 . The apparatus of  claim 1 , wherein the separation between the first and second sample sites exceeds the separation between the initiation position and the termination position.  
     
     
         15 . The apparatus of  claim 1  further comprising a housing configured to support and enclose a least a portion of the apparatus, where the initiation position and the termination position are referenced relative to a fixed portion of the housing.  
     
     
         16 . The apparatus of  claim 1 , wherein the first sample site moves past the termination position before the second sample site moves into the initiation position.  
     
     
         17 . The apparatus of  claim 1 , wherein the light transmitted from the substrate includes light selected from the group consisting of fluorescence, phosphorescence, and chemiluminescence.  
     
     
         18 . The apparatus of  claim 1 , the composition being contained in a spatial volume lying between boundary interfaces located at different points along a Z-axis, wherein the Z-axis is substantially perpendicular to the stage.  
     
     
         19 . The apparatus of  claim 1 , wherein the substrate further includes a third sample site, and wherein the sensed volume returns to the initiation position after the second sample site passes the termination position to track the third sample site as it moves between the initiation position and the termination position.