Radiation detector

Abstract

In a radiation detector, an active matrix board is formed of switching elements of polycrystalline silicon thin film transistors produced by a poly-silicon (poly-Si) process, charge storage capacitances, insulating layers, electrodes, gate lines and data lines, on which a converting layer is formed by polycrystalline, such as CdTe and CdZnTe, having a high sensitivity with respect to light and radiation at a film-forming temperature higher than 300° C. A gate driving circuit and a signal reading-out circuit are provided on the active matrix board, and signals of the respective images are scanned to take out to the outside. Thus, by using the high heat resistant matrix process board, the radiation detector having a wide dynamic range and a high signal to noise (S/N) ratio can be obtained.

What is claimed is:  
     
         1 . A radiation detector comprising: 
 an active matrix board including gate lines and data lines arranged in a two-dimensional lattice form, a plurality of high-speed switching elements provided at respective lattice points and connected to the gate lines and the data lines, each having a source electrode, pixel electrodes connected to the source electrodes of the high-speed switching elements, and charge storage capacitances, each being disposed between the pixel electrode and a ground electrode, said active matrix board being formed of a poly-silicon process board; and    a converting layer formed on the pixel electrodes to generate a pair of electron-hole by absorbing one of light and radiation.    
     
     
         2 . A radiation detector according to    claim 1   , wherein said converting layer for generating the pair of electron-hole by absorbing one of light and radiation is a polycrystalline film of one of CdTe and CdZnTe.  
     
     
         3 . A radiation detector according to    claim 1   , wherein said high-speed switching elements are formed of polycrystalline silicon thin film transistors.  
     
     
         4 . A radiation detector according to    claim 3   , wherein said active matrix board further includes a base plate having high heat resistance and insulating property, an insulating film disposed on the base plate and sandwiched by the gate lines and data lines, an insulating protecting layer disposed on the insulating film above the switching element, and a common electrode disposed on the converting layer.  
     
     
         5 . A radiation detector according to    claim 4   , further comprising gate driving circuit to be connected to the gate lines, a signal driving circuit to be connected to the data lines, and a signal process circuit formed on the active matrix board for connecting the gate lines and data lines to the gate driving circuit and the signal process circuit.