Pixel AEC flat panel detector

Abstract

The invention provides a pixel AEC flat panel detector. The pixel AEC flat panel detector comprises a pixel array, a gate drive signal control circuit, a normal pixel signal reading circuit, an AEC signal control processing system, an image information acquisition system and an image information processing system, wherein the pixel array comprises a plurality of normal pixel units and a plurality of AEC pixel units, wherein the plurality of normal pixel units form an array, the plurality of AEC pixel units are distributed in the array by means of replacing normal pixels in the array, each of the normal pixel units is composed of a thin film transistor switch and a photodiode, and each of the AEC pixel units is composed of a photodiode. The pixel AEC flat panel detector provided by the invention is capable of accurately detecting an exposure starting time, automatically controlling an exposure ending time, and automatically controlling an exposure dose. The pixel AEC flat panel detector provided by the invention is simple in structure and suitable for industrial production.

Description

technical field [0001] The invention relates to a DR digital flat panel system, in particular to a pixel AEC flat panel detector. Background technique [0002] AEC, the full name of Automatic Exposure Control, means automatic exposure control, which is an image exposure dose control technology used in X-ray imaging systems. Its purpose is to reduce the X-ray radiation dose suffered by patients under the premise of ensuring image quality. Usually an AEC device is placed between the patient to be diagnosed and the flat panel detector, of course there are AEC devices placed under the flat panel detector. After the AEC device detects the X-rays passing through the diagnosed patient, it generates an electrical signal. Since the electrical signal is proportional to the total dose of X-rays received by the flat-panel detector, it is used to identify the X-ray received by the flat-panel detector. Whether the amount of ray exposure is up to standard, once the electrical signal cons...

AI Technical Summary

Problems solved by technology

Its first AEC pixel unit structure design is to short-circuit the source and drain poles of the TFT to short-circuit the TFT without any other changes, so that the pixel capacitance is in a permanent readout state, but this circuit structure will inevitably lead to broken lines; The second structure is to disconnect the TFT switch from the photodiode pixel capacitor. The pixel capacitor has an independent readout circuit and does not share a readout circuit with the normal pixel unit. This design does not introduce bad lines, but useless TFTs are still preserved. Reduce the aperture ratio of the pixel unit; the third design is to independently design the AEC photosensitive detector outside the AA area, and its direction is parallel to the dataline of the normal pixel unit. This design does not need to sacrifice the normal pixel unit, but complicates the image detector. Circuit structure design and manufacturing process; the fourth type of AEC pixel unit only has photodiode pixel capacitors, which share a set of readout circuits with normal pixel units, and the result is that bad lines will inevitably be introduced and image quality will be reduced; the fifth method is to short-circuit the TFT switch The source and drain poles of the AEC pixel unit and the normal pixel unit share a set of readout circuits, which will inevitably lead to a bad line, but its AEC electrical signal is determined by the difference between the electrical signal of the bad line row (column) and the adjacent normal row (column) value acts as

The sixth structure adopts the independent gateline design of the AEC pixel unit. The AEC pixel unit maintains the structure of the normal pixel unit, but has an independent gateline readout scanning drive system. This structural design can avoid bad lines, but inevitably increases the image detector The complexity of layout and manufacturing process, while reducing the aperture ratio of the row (column) pixel unit

For all AEC pixel units with different structures, another common problem is the increase of system noise

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