Electrostatic imaging apparatus
AssigneeThe University of Texas System
InventorsPoen S. Ong, Alfonso Zermeno, Lee M. Marsh, Jr., James M. Hevezi, Ronald W. Cowart
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Abstract
An image scanning apparatus for obtaining radiographic information from a detector system. The apparatus produces a video signal by optical readout of a latent image found in a detector system. The video signal is processed and displayed to provide radiographic information.
Claims19
A method of recording and reading out a latent image comprising:
- exposing a multilayered detector apparatus whose photoconductive layer has no surface potential to a modulated radiation flux capable of producing electron hole pairs, said photoconductive layer being biased by an electric field during said exposure, whereby a modulated surface charge is placed on the photoconductive layer;
- scanning said exposed detector with a photon beam whereby said modulated surface charge is at least partially discharged;
- and
- measuring the charging potential of said discharge as a function of time.
An apparatus for reading out the latent image stored as variations in surface charge on a photoconductive layer in a multilayered photon detector apparatus comprising:
- a light-tight housing;
- a holder capable of receiving said detector at one end of said housing;
- a laser producing a thin beam of light located within said housing;
- said laser being pulse modulated in a recurring pattern of 5 nanoseconds to 5 microseconds of "on" time followed by 5 nanoseconds to 10 microseconds of "off" time;
- scanning means for directing said beam of light in a regular raster pattern over said detector's photoconductive layer;
- signal acquisition means operably connected to said detector for measuring the variable discharge potential flowing in said photoconductive layer as it is scanned by said light beam;
- display means responsive to said signal acquisition means for displaying image information contained in said variable discharge potential.
A mass screening system for obtaining radiographs comprising:
- a source of X-rays;
- a light-tight housing spaced apart from said source and adapted to permit a patient to place the body part being X-rayed against the side of the housing proximate said source;
- a multilayered photon detector apparatus mounted in said housing proximate said source, said multilayered photon detector comprising:
- a first conductive layer;
- a photoconductive layer in electrical contact with said first conductive layer;
- a transparent insulating layer affixed to said photoconductive layer, said photoconductive layer disposed between said transparent insulating layer and said first conductive layer;
- and
- a transparent conductive layer affixed to said transparent insulating layer, said transparent insulating layer disposed between said transparent conductive layer and said photoconductive layer, said first conductive layer of said detector being covered with an insulative layer and faces said source;
- means for scanning said photoconductive layer of said detector with a thin beam of light;
- control means operably connected to said X-ray source and said scanning means for sequentially exposing said detector to X-rays from said source after their passage through a patient and then scanning said thin light beam in a regular raster pattern over the surface of said photoconductive layer;
- signal acquisition means operably connected and responsive to said detector for reading out the latent image on said detector while it is scanned by said light beam;
- video display means connected and responsive to said signal acquisition means for displaying the latent image readout of said detector.
Dependencies are inferred from the claim text.