The Chinese full name of fpd is

Fpd is called flat panel detector in Chinese.

Flat panel detector is a kind of precise and expensive equipment, which plays a decisive role in imaging quality. Being familiar with the performance index of the detector is helpful to improve the imaging quality and reduce the X-ray radiation dose.

Digital X-ray photography (DR for short) has become the dominant direction of digital X-ray photography technology because of its obvious advantages of faster imaging speed, more convenient operation and higher imaging resolution. DR flat panel detector can be divided into two ways in terms of energy conversion: indirect conversion flat panel detector and direct conversion flat panel detector.

Principle of flat panel detector;

There are two kinds of flat panel detectors: amorphous silicon flat panel detector and amorphous selenium flat panel detector.

Amorphous selenium flat panel detector is a direct flat panel detector structure, which is mainly composed of collector matrix, selenium layer, dielectric layer, top electrode and protective layer.

Amorphous selenium array directly converts X-rays into electrical signals and stores them in storage capacitors. The pulse control gate circuit turns on the thin film transistor, and the charge stored in the storage capacitor is delivered to the charge amplifier for output, thus completing the conversion of photoelectric signals, which are then converted into digital images by the digital converter and input to the computer.

Amorphous silicon flat panel detector is an indirect digital X-ray imaging. Its basic structure is that the surface is a layer of scintillator material, the next layer is a photodiode circuit made of amorphous silicon, and the bottom layer is a charge readout circuit.

The scintillator located on the surface of the detector converts X-rays attenuated after passing through the human body into visible light, and the amorphous silicon photodiode array below the scintillator converts visible light into electrical signals, forming stored charges on the photodiode's own capacitance, then scanning and reading the stored charges of each pixel, outputting digital signals after A/D conversion, and transmitting them to a computer for image processing, thus forming X-ray digital images.