Patent ID: 7768645
Filing Date: 2010-08-03
Classification: G01N

Abstract:
1. A miniature readhead for a photometric diagnostic instrument for detecting color information from a target area using ambient light, the readhead comprising: a housing having a hand-held form factor, including a plate and a tray configured for being superposed with one another, said tray configured for receiving reagent sample media therein, the sample media having a plurality of test areas disposed in spaced relation thereon, each of the test areas configured to react with a sample when disposed in contact with the sample and to change color according to an amount of an analyte in the sample; the tray sized and shaped for forming an indexed fit with the sample media; said plate being optically transmissive, wherein ambient light is transmissible therethrough to the sample media indexed within the tray; an array of light detectors disposed in spaced relation along said plate; said array including sets of light detectors configured to respectively detect light of at least three mutually distinct wavelengths; each set configured to receive diffuse, non-specular reflections of light from a respective one of the test areas when the sample media is indexed within said tray; a plurality of light shields superposed with each of said light detectors to selectively permit ambient light to pass to the tray, while substantially preventing ambient light from reaching the light detectors prior to reflecting from the test areas; and said readhead being operable free of any non-ambient light sources.