Sensor and device for lifetime imaging and detection applications

Abstract

A method of luminance lifetime imaging includes receiving incident photons at an integrated photodetector from luminescent molecules. The incident photons being received through one or more optical components of a point-of-care device. The method also includes detecting arrival times of the incident photons using the integrated photodetector. A method of analyzing blood glucose includes detecting luminance lifetime characteristics of tissue using, at least in part, an integrated circuit that detects arrival times of incident photons from the tissue. The method also includes analyzing blood glucose based upon the luminance lifetime characteristics.

What is claimed is: 
     
         1 . An eye imaging and/or measuring device comprising:
 an integrated photodetector comprising:
 a photodetection region configured to, in response to receiving incident photons from and/or reflected by a subject's eye, generate charge carriers; 
 a charge carrier storage region electrically coupled to the photodetection region by a charge carrier travel region; 
 a first electrode configured to:
 receive, from a control circuit, a first signal; 
 establish, in response to receiving the first signal, in the charge carrier travel region, an electric potential allowing the charge carriers to travel, in the charge carrier travel region, from the photodetection region toward the charge carrier storage region; 
 receive, from the control circuit, a second signal; and 
 produce, in response to receiving the second signal, in the charge carrier travel region, a potential barrier; and 
 
 a second electrode configured to:
 receive, from the control circuit, a third signal; 
 produce, in response to receiving the third signal, a potential barrier, wherein the first and second electrodes are positioned such that, when the first electrode receives the second signal and the second electrode receives the third signal, the potential barriers confine at least some of the charge carriers between the first and second electrodes. 
 
   
     
     
         2 . The eye imaging and/or measuring device of  claim 1 , wherein the charge carrier storage region is positioned such that, when the potential barrier confines charge carriers between the first and second electrodes, the charge carriers are stored in the charge carrier storage region. 
     
     
         3 . The eye imaging and/or measuring device of  claim 1 , wherein the photodetection region has an electric field established therein to force the charge carriers toward the charge carrier storage region via the charge carrier travel region. 
     
     
         4 . The eye imaging and/or measuring device of  claim 1 , wherein the photodetection region has a spatially graded doping profile. 
     
     
         5 . The eye imaging and/or measuring device of  claim 1 , further configured to establish a potential gradient from the photodetection region toward the at least one charge carrier storage region. 
     
     
         6 . The eye imaging and/or measuring device of  claim 1 , further comprising an excitation light source configured to illuminate the subject's eye to cause emission of the incident photons toward the integrated photodetector, wherein charge carriers are aggregated in the at least one charge carrier storage region over a course of a plurality of excitations of the excitation light source. 
     
     
         7 . The eye imaging and/or measuring device of  claim 2 , wherein the integrated photodetector further comprises:
 a second charge carrier storage region electrically coupled to the photodetection region by a charge carrier travel region;   a third electrode configured to:
 receive, from a control circuit, a fourth signal; 
 establish, in response to receiving the fourth signal, in the charge carrier travel region, an electric potential allowing the charge carriers to travel, in the charge carrier travel region, from the photodetection region toward the second charge carrier storage region; 
 receive, from the control circuit, a fifth signal; and 
 produce, in response to receiving the fifth signal, in the charge carrier travel region, a potential barrier; and 
   a fourth electrode configured to:
 receive, from the control circuit, a sixth signal; 
 produce, in response to receiving the sixth signal, a potential barrier, wherein the third and fourth electrodes are positioned such that, when the third electrode receives the fifth signal and the fourth electrode receives the sixth signal, the potential barriers confine the charge carriers between the third and fourth electrodes. 
   
     
     
         8 . The eye imaging and/or measuring device of  claim 7 , wherein the second charge carrier storage region is positioned such that, when the potential barrier confines the charge carriers between the third and fourth electrodes, the charge carriers are stored in the second charge carrier storage region. 
     
     
         9 . An eye imaging and/or measuring device, comprising:
 an integrated photodetector, comprising:
 a photodetection region configured to, in response to receiving incident photons from and/or reflected by a subject's eye, generate charge carriers; 
 a first electrode; 
 a second electrode; and 
 a charge carrier storage region positioned between the first and second electrodes; and 
   a processor configured to:
 provide, to the first electrode, at a first predetermined incident photon arrival time, a first signal, the first signal establishing an electric potential that allows the charge carriers to travel from the photodetection region toward the charge carrier storage region; 
 provide, to the first and second electrodes, at a second predetermined incident photon arrival time, second signals, the second signals producing potential barriers that confine at least some of the charge carriers between the first and second electrodes for storing in the charge carrier storage region. 
   
     
     
         10 . The eye imaging and/or measuring device of  claim 9 , wherein the processor is further configured to associate, based on the first and second predetermined incident photon arrival times, a number of the charge carriers stored in the charge carrier storage region with fluorescence lifetime information. 
     
     
         11 . The eye imaging and/or measuring device of  claim 9 , wherein the photodetection region has an electric field established therein to force the charge carriers toward the charge carrier storage region. 
     
     
         12 . The eye imaging and/or measuring device of  claim 9 , wherein the photodetection region has a spatially graded doping profile. 
     
     
         13 . The eye imaging and/or measuring device of  claim 9 , further configured to establish a potential gradient from the photodetection region toward the at least one charge carrier storage region. 
     
     
         14 . The eye imaging and/or measuring device of  claim 9 , further comprising an excitation light source configured to illuminate the subject's eye to cause emission of the incident photons toward the integrated photodetector, wherein charge carriers are aggregated in the at least one charge carrier storage region over a course of a plurality of excitations of the excitation light source. 
     
     
         15 . The eye imaging and/or measuring device of  claim 10 , wherein:
 the integrated photodetector further comprises:
 a third electrode; 
 a fourth electrode; and 
 a second charge carrier storage region positioned between the third and fourth electrodes; and 
   the processor is further configured to:
 provide, to the third electrode, at a third predetermined incident photon arrival time, a third signal, the third signal establishing an electric potential that allows the charge carriers to travel from the photodetection region toward the second charge carrier storage region; 
 provide, to the third and fourth electrodes, at a fourth predetermined incident photon arrival time, fourth signals, the fourth signals producing potential barriers that confine at least some of the charge carriers between the third and fourth electrodes for storing in the second charge carrier storage region. 
   
     
     
         16 . The eye imaging and/or measuring device of  claim 15 , wherein the third and fourth predetermined incident photon times associate the charge carriers stored in the second charge carrier storage region with second fluorescence lifetime information. 
     
     
         17 . The eye imaging and/or measuring device of  claim 9 , further comprising:
 an excitation light source configured to emit excitation light; and   a plurality of optical components configured to:
 illuminate the subject's eye with the excitation light; 
 receive incident photons from the subject's eye; and 
 provide the incident photons to the integrated photodetector. 
   
     
     
         18 . The eye imaging and/or measuring device of  claim 9 , wherein the plurality of optical components comprises a dichromic mirror configured to reflect and/or refract one of the excitation light and the incident photons and transmit the other of the excitation light and the incident photons. 
     
     
         19 . A method of eye imaging and/or measuring, the method comprising:
 receiving, at a photodetection region of an integrated photodetector, incident photons from and/or reflected by a subject's eye;   generating, in the photodetection region in response to receiving the incident photons, charge carriers;   providing, by a processor to a first electrode, at a first predetermined incident photon arrival time, to establish an electric potential that allows the charge carriers to travel from the photodetection region toward a charge carrier storage region, a first signal;   providing, by the processor to the first electrode and a second electrode, at a second predetermined incident photon arrival time, to produce potential barriers that confine the charge carriers between the first and second electrodes for storing in the charge carrier storage region, second signals.   
     
     
         20 . The method of  claim 19 , further comprising associating with fluorescence lifetime information, by the processor, based on the first and second predetermined incident photon arrival times, a number of the charge carriers stored in the charge carrier storage region.