Patent ID: 7884438

Claim:
A photodetector comprising: a semiconductor conversion layer having a first surface and a second surface disposed opposite the first surface; a first electrode coupled to the first surface of the semiconductor conversion layer; a second electrode coupled to the second surface of the semiconductor conversion layer; a low density substrate coupled to the second electrode opposite the semiconductor conversion layer, the low density substrate including a detector array; a high density layer disposed over the first electrode opposite the semiconductor conversion layer; a protective layer disposed between the high density layer and the first electrode, wherein the protective layer comprises a material that is non-reactive with the high density layer, wherein the protective layer comprises one of a paralyene C, a polyethylene terephthalate, an acrylic or vinyl polymer that is formed from a material including the acrylic or vinyl polymer, toluene and methyl ethyl ketone, and an acrylic to protect one of the semiconductor conversion layer, the first electrode, the second electrode, and the substrate from damage due to one of air, humidity, and corrosion; wherein the high density layer includes a thickness of a high density material to create a number of photoelectrons caused by mega-voltage x-ray photons incident upon the high density layer, the photoelectrons to be received by the semiconductor conversion layer; wherein the first electrode includes a thickness of another high density material to create a number of photoelectrons caused by mega-voltage x-ray photons incident upon the first electrode to be received by the semiconductor conversion layer; wherein the semiconductor conversion layer includes a thickness of a photo-conductive material to convert photoelectrons received from one of the high density layer and the first electrode to free charge carriers for detection by the detector array, wherein detected free charge carriers provide an image, and wherein the low density substrate has a density and thickness so that mega-voltage x-ray photons incident upon the low density substrate create no more than an insubstantial amount of photoelectrons to be converted by the semiconductor conversion layer.