Patent ID: 7608463

Claim:
An optical assay apparatus for detecting an analyte in a sample, said optical assay apparatus comprising: (a) a light source module operable to produce an output of excitation light rays having respective wavelengths that fall in a range from about 600 nm to about 700 nm; (b) an optical sensor optically coupled with said light source module, wherein said optical sensor comprises a light ray redirection portion and an assay sensing portion; wherein said assay sensing portion comprises a sensing waveguide and a sensor chemistry coating on said sensing waveguide; wherein said sensing waveguide comprises an input end and an optical axis at said input end; wherein said light ray redirection portion is operable to receive at least some of said excitation light rays produced by said light source module and to correspondingly provide to said sensing waveguide an output of reflected excitation light rays directed at an approximately constant angle with respect to said optical axis at said input end of said sensing waveguide; wherein, during use of said optical assay apparatus, said sensor chemistry coating comprises a fluorophore, at least some of said output of reflected excitation light rays passes through said sensing waveguide and creates an evanescent electric field in said sensor chemistry coating, said fluorophore emits an output of signal recovery light rays in response to said evanescent electric field as a function of a presence of said analyte in said sample, and said sensing waveguide transports a collected portion of said signal recovery light rays; and (c) an interrogation module optically coupled with said optical sensor and operable to receive from said sensing waveguide at least some of said collected portion of said signal recovery light rays; wherein said interrogation module comprises: (i) a photodetector; and (ii) a filter; wherein said filter is located between said photodetector and said optical sensor, and is selected to block greater than about 99.9 percent of said respective wavelengths of said excitation light rays produced by said light source module and to have a transmission of greater than about 50 percent at wavelengths longer than a wavelength that is at least about 25 nm longer than a longest one of said respective wavelengths of said excitation light rays produced by said light source module, to enable said filter to minimize how many of said excitation light rays produced by said light source module reach said photodetector from said filter, while maximizing how many of said signal recovery light rays in said collected portion of said signal recovery light rays reach said photodetector from said filter; and wherein said photodetector is operable to generate a corresponding output signal from said signal recovery light rays that reach said photodetector from said filter.