Radiation image detector
View Patent ↗A TFT readout system radiation image detector capable of satisfactorily removing noise signals generated by the parasitic capacitors formed in the vicinity of the respective intersections between gate control signal lines and charge signal lines with a simple and inexpensive circuit configuration. The detector includes charge detecting elements for storing charges generated by receiving radiation; gate control signal lines through which a gate control signal flows to control the switching element of each charge detecting element; charge signal lines to which charge signals stored in the storage sections flow out; and dummy signal lines, each being installed adjacent to each of the corresponding charge signal lines. The dummy signal flowed out to each dummy signal line is subtracted from the signal flowed out to each charge signal line when the gate signal is flowed through the gate control signal line by the differential amplifier.
1. A radiation image detector, comprising:
(a) a radiation image recording medium, including:
(1) a charge generating section for generating charges by receiving radiation carrying a radiation image;
(2) multitudes of charge detecting elements disposed two-dimensionally in orthogonal directions, each having a storage section for storing the charge generated in the charge generating section, and a switching element for reading out the charge signal stored in the storage section;
(3) multitudes of charge signal lines for receiving the charge signals flowing out from the storage sections, each of the charge signal lines being installed in parallel with each column of the charge detecting elements disposed in either direction of the orthogonal directions;
(4) multitudes of gate control signal lines for receiving a gate control signal for controlling the switching elements ON and OFF, each of the gate control signal lines being installed in parallel with each row of the charge detecting elements disposed in the other direction of the orthogonal directions; and
(b) a detecting section for detecting the charge signals flowed out to the charge signal lines of the radiation image recording medium,
wherein:
the radiation image recording medium further includes multitudes of dummy signal lines, each being installed adjacent to each of the corresponding charge signal lines in parallel; and
the detecting section includes a subtracting means for subtracting each of the dummy signals flowed out to each of the dummy signal lines installed adjacent to each of the corresponding charge signal lines from each of the charge signals flowed out to each of the charge signal lines when the gate control signal is flowed through the gate control signal lines.
2. The radiation image detector according to claim 1 , wherein the detecting section includes multitudes of differential amplifiers as the subtracting means; and each of the charge signal lines and each of the dummy signal lines installed adjacent to each of the corresponding charge signal lines are connected to each of the corresponding differential amplifiers.
3. The radiation image detector according to claim 2 , wherein the differential amplifier is a charge amplifier; and each charge signal line and each corresponding dummy signal line are connected to the inverting input terminal and non-inverting input terminal of the charge amplifier respectively, the non-inverting terminal being grounded through a capacitor having a capacitance value which is equal to the feedback capacitance of the charge amplifier.