CN101335842B - Image detection device and method for driving image detector - Google Patents
Image detection device and method for driving image detector Download PDFInfo
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- CN101335842B CN101335842B CN2008101288769A CN200810128876A CN101335842B CN 101335842 B CN101335842 B CN 101335842B CN 2008101288769 A CN2008101288769 A CN 2008101288769A CN 200810128876 A CN200810128876 A CN 200810128876A CN 101335842 B CN101335842 B CN 101335842B
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Abstract
The invention discloses an image detection device has an image detector equipped with a detection section having a charge generation section that receives irradiation of electromagnetic waves and generates charges, a storage capacitor in which two electrodes are disposed so as to oppose one another and which accumulates charges generated at the charge generation section, and a TFT switching element for reading out charges accumulated in the storage capacitor. At a time before a point in time of reading out of charges from the storage capacitor via the switching element of the image detector, a reference potential of the storage capacitor is varied by a variable Cs power source, and leak current sufficiently flows before reading out of a charge signal from the image detector. Leak current is thereby reduced sufficiently at a time of reading out the charge signal.
Description
Technical field
The present invention relates to a kind of image detection device with visual detector, a large amount of pixels are by two-dimensional arrangements in described visual detector, and described pixel has thin-film transistor (TFT) switch element, and the present invention relates to a kind of method that drives visual detector.
Background technology
FPD (flat-panel detector) is put to actual use in recent years, and the X ray photosensitive layer is set in the tft active matrix array in described FPD, and described FPD can directly be converted to numerical data with X ray information.Compare with traditional imaging plate, the advantage of FPD is: image can be confirmed immediately and mobile image also can be identified, and the popularization of FPD is very fast.
At first, will utilize Figure 15 to describe traditional sciagraphy visual detector.Figure 15 is the schematic diagram of the equivalent electric circuit of 3 * 3 pixels.In Figure 15, Reference numeral 211 is imageing sensor parts, the 212nd, and the TFT switch, the 213rd, charge storage capacitor, the 214th, scan line, the 215th, data wire, and 216 are signal detectors.
The characteristics of the sciagraphy visual detector of this FPD of being known as are: owing to picture signal can directly be detected, so can accurately detect the sciagraphy image.Yet there is such situation in more any in a variety of causes, and various types of noises are introduced in the picture signal of wanting detected at first.
For instance, the leakage current of TFT switch is exactly one type a noise.Preferably, when being used to select to detect the shutoff operation of pixel, the TFT switch do not have leakage current fully.Yet, according to device property, the leakage current flow of known quantity is arranged, and this amount is added in the picture signal.In order to overcome this problem, for instance, Japanese Patent Application Publication (JP-A) No.2003-319264 has proposed a kind ofly to read leakage current and by utilizing the method for this leakage current value correction image signal when the TFT switch is closed.
Yet, utilize the method for describing among the JP-ANo.2003-319264, picture quality is not improved inevitably.Its reason is because in the method for JP-ANo.2003-319264, the processing that deducts the leakage current component from picture signal is used to correct magnitude of leakage current.Because the leakage current component is a random noise, so even the leakage current component is deducted from picture signal, the result remains the bonus values and the leakage current component of picture signal, and noisiness increases.In addition, there is such problem: exist the result to cause the possibility of deteriroation of image quality.
In addition, also be major issue for the above-mentioned needed processing time of leakage current correction.In medical diagnosis, because photographical condition must be optimised according to patient, so it is very high to obtain the frequency of image again, and image must be identified after taking pictures as far as possible immediately.In addition, the X-ray detector that is used for the image of moving process obviously can not spend than frame frequency more time.Also have, the cost that is used for the required peripheral circuit of correcting process (for example memory etc.) is very high, and when efforts be made so that the processing time is faster, even need the Circuits System of costliness more.
Summary of the invention
Because it is foregoing, the purpose of this invention is to provide a kind of image detection device and a kind of method that drives visual detector, described method can suppress the influence of the leakage current described the front, and has previously described deterioration of image quality, the correction time prolongs or circuit cost increases problem.
A first aspect of the present invention is a kind of image detection device, described image detection device comprises: visual detector, described visual detector is equipped with test section, described test section has charge generation portion, holding capacitor and TFT switch element, described charge generation portion receives the electromagenetic wave radiation that is used to write down and produces electric charge, two electrodes are set in the described holding capacitor with toward each other, this holding capacitor is accumulated in the electric charge that described charge generation portion is produced, and in this holding capacitor, electromotive force according to the quantity of electric charge that is accumulated and an electrode as a reference, the electromotive force of another electrode changes thereupon, and described TFT switch element is used for reading the electric charge that is accumulated in described holding capacitor; Power supply unit, described power supply unit are connected so that can be to a described electrode application voltage; And control part, described control part control imposes on the voltage of a described electrode from power supply unit, thereby by the predetermined amount of time before from visual detector, reading, promote flowing from the leakage current of switch element for the electric charge in being accumulated in holding capacitor.
The image detection device control of first aspect present invention is applied to the voltage of a described electrode, thereby make and read predetermined amount of time before for the electric charge that is accumulated in the holding capacitor from visual detector, leakage current flows from switch element and becomes easy.Therefore, because before charge signal was read from visual detector, leakage current can be fully mobile, so when reading charge signal, leakage current can fully be reduced.Thereby the noise that is caused by leakage current can be lowered.
In the image detection device of first aspect present invention, control part can be controlled the voltage that is applied to a described electrode in preset time, described predetermined amount of time after the electromagnetic wave that is used for writing down is radiated on the visual detector until the time period process of electric charge before visual detector is read out.
The influence of leakage current when reading image can diminish by constructing aforesaid image detection device, promptly, be applied to the voltage of a described electrode by control in the image detection device of first aspect present invention, make in preset time, leakage current flows from switch element and becomes easily, described preset time the electromagnetic wave that is used for writing down is radiated on the visual detector after up to the time period process of electric charge before visual detector is read out.
In the image detection device of first aspect present invention, control part can be controlled the voltage that is applied to a described electrode in the preset time section, described preset time section comprises the time period that the electromagnetic wave that is used to write down is radiated on the visual detector to be continued.
By constructing aforesaid image detection device, promptly, be applied to the voltage of a described electrode by control in the preset time section, wherein said preset time section comprises the period when the electromagnetic wave that is used to write down is radiated on the visual detector, the influence of the leakage current when reading image can be diminished, and can be accelerated the readout time of image further.
The TFT switch element that visual detector has can have the defencive function for voltage; described defencive function protective circuit prevents owing to the risk that is accumulated in the holding capacitor when electric charge and the electromotive force of other electrode electric current when becoming more than or equal to set-point flows and causes.
By constructing aforesaid image detection device, that is, by the defencive function for voltage is provided to the TFT switch element, the characteristic of leakage current becomes characteristic as shown in Figure 6, and this characteristic will be described later, and realizes that effect of the present invention becomes easy.
In addition, power supply unit can be set on the peripheral circuit substrate, and described peripheral circuit substrate is independent of visual detector and is provided with.
By constructing aforesaid image detection device, promptly, by power supply unit being set being independent of on the peripheral circuit substrate that visual detector is provided with, power supply with big capacity, large-scale PC and analog can be installed, and when the voltage of this power supply unit of switch, can be so that power supply noise reduces.
The image detection device of first aspect present invention can also comprise signal detector, described signal detector detects the stored charge amount by the electromotive force that detects the charge signal of reading from the test section of visual detector, and when detecting the electromotive force of charge signal, the electromotive force of reference electrode line can be configured to identical potential level with the electromotive force of a described electrode that constitutes holding capacitor, and described reference electrode line is the reference that signal detector detects.
By constructing aforesaid image detection device, can be reduced at the leakage current when visual detector is read charge signal, and detection noise can be reduced, promptly, by making image detection device further comprise signal detector, the electromotive force that described signal detector detects by detecting the charge signal of reading from the test section of visual detector detects the stored charge amount, and when detecting the electromotive force of charge signal, make the electromotive force of reference electrode line and the electromotive force of a described electrode that constitutes holding capacitor be in identical level, described reference electrode line is the detection reference in the signal detector.For instance, just, under the situation that the electromotive force of the electromotive force of the reference electrode line of signal detector and a described electrode is offset with respect to each, for example, under the high situation of the electromotive force of a described electrode, unified electric current always from a described electrode effluent to the signal detector side.Just, original, when the quantity of electric charge that accumulates in holding capacitor finishes to flow, the current vanishes that flows to signal detector from test section.Yet, because phenomenon recited above, leakage current when detecting (because constant current that the difference between the electromotive force of the electromotive force of the reference electrode line of signal detector and a described electrode causes) increases, and because this, white noise (noise of constant level) raising.Therefore, if the electromotive force of the electromotive force of signal detector reference electrode and a described electrode is set at par as mentioned above, then previously described white noise can be lowered.
In the image detection device of first aspect present invention, preferably, described predetermined amount of time is to 1s from 100 μ s.
If predetermined amount of time is configured to from 100 μ s to 1s, can be so that fully flow and can not make operating efficiency worsen from the leakage current of switch element.
The image detection device of second aspect present invention comprises: visual detector, described visual detector is equipped with test section, holding capacitor and TFT switch element, described test section has charge generation portion, described charge generation portion receives the irradiation of electromagnetic waves that is used to write down and produces electric charge, two electrodes are set in this holding capacitor with toward each other, and described holding capacitor is accumulated in the electric charge that charge generation portion produces, and in described holding capacitor according to the electromotive force of the quantity of electric charge that is accumulated and an electrode as a reference, the electromotive force of another electrode changes thereupon, and described TFT switch element is used for reading the electric charge that is accumulated in holding capacitor; And voltage applying circuit, described voltage applying circuit applies controlled voltage to a described electrode, to change the leakage current from switch element.
The image detection device of second aspect present invention is provided with voltage applying circuit, and described voltage applying circuit changes the leakage current from the switch element of visual detector.Therefore, from the leakage current of switch element can be as will be described later Be Controlled, and, because leakage current is fully mobile before charge signal is read from visual detector, so leakage current can fully be reduced when reading charge signal.Thereby the noise that causes owing to leakage current can be lowered.
A third aspect of the present invention is a kind of method that drives visual detector, described visual detector is equipped with test section, described test section has charge generation portion, holding capacitor and TFT switch element, described charge generation portion receives the irradiation of electromagnetic waves that is used to write down and produces electric charge, two electrodes are set in this holding capacitor with toward each other, and described holding capacitor is accumulated in the electric charge that charge generation portion produces, and in described holding capacitor, electromotive force according to the quantity of electric charge that is accumulated and an electrode as a reference, the electromotive force of another electrode changes thereupon, described TFT switch element is used for reading the electric charge that is accumulated in holding capacitor, described method comprises: produce the electromagnetic wave be used to write down, and with this electromagenetic wave radiation to charge generation portion; For the predetermined amount of time before the time point of from holding capacitor, reading electric charge via switch element, change the voltage that is applied on the described electrode, to promote leakage current from switch element; And the console switch element also detects the electric charge that is accumulated in the holding capacitor.
Visual detector driving method according to third aspect present invention, time before the time point of from holding capacitor, reading electric charge via the switch element of visual detector, the voltage that is applied on the described electrode is changed, and becomes easy thereby make leakage current flow from switch element.Therefore, from the leakage current of switch element can be as will be described later Be Controlled, and since before charge signal is read from visual detector leakage current fully mobile, so leakage current can fully be reduced when reading charge signal.Thereby the noise that causes owing to leakage current can be lowered.
Description of drawings
Fig. 1 is the schematic structural representation of sciagraphy image detecting system that is employed first exemplary embodiments of image detection device of the present invention;
Fig. 2 is the plane graph of structure that a pixel cell of sciagraphy visual detector is shown;
Fig. 3 is the cutaway view of structure that a pixel cell of sciagraphy visual detector is shown;
Fig. 4 is the schematic equivalent circuit of a pixel cell of sciagraphy visual detector;
Fig. 5 is the figure that is illustrated in the leakage current characteristic of the TFT switch under the situation that does not have the TFT protective circuit;
Fig. 6 is the figure that is illustrated in the leakage current characteristic of the TFT switch under the situation with TFT protective circuit;
Fig. 7 is the figure that shows another example of structure of variable C s power supply;
Fig. 8 is the time diagram that is used for the embodiment of interpretation of images detector drive method, and this visual detector is relevant with first exemplary embodiments of the present invention;
Fig. 9 is the figure that is used to explain traditional driving method of sciagraphy visual detector;
Figure 10 is the functional block diagram of the sciagraphy image detecting system shown in Fig. 1;
Figure 11 is the structural representation of sciagraphy image detecting system that is applied to second exemplary embodiments of image detection device of the present invention;
Figure 12 is the equivalent circuit diagram of a pixel cell of sciagraphy visual detector shown in Figure 11;
Figure 13 A is the figure that is used to explain the leakage current of the TFT switch under the situation of not protecting diode; And Figure 13 B is the figure that is used to explain at the leakage current with the TFT switch under the situation of protecting diode;
Figure 14 is used to explain under the situation of the embodiment that realizes visual detector driving method of the present invention the figure of the leakage current of TFT switch;
Figure 15 is the structural representation of traditional sciagraphy visual detector;
Figure 16 is the time diagram of embodiment that is used for the driving method of interpretation of images detector, and the 3rd exemplary embodiments of this visual detector and the present invention is relevant;
Figure 17 is the time diagram that is used for the embodiment of interpretation of images detector drive method when the capture movement image; And
Figure 18 is the time diagram that is used for the embodiment of interpretation of images detector startup method when the shooting that twice and energy reduce.
Embodiment
The situation that is applied to the sciagraphy image detecting system in the present invention will describe with reference to accompanying drawing below.
Fig. 1 is the structural representation of the sciagraphy image detecting system relevant with first exemplary embodiments.
As shown in Figure 1, this sciagraphy image detecting system has the sciagraphy image detection device 100 of reading the sciagraphy picture signal from the sciagraphy visual detector, and the display 200 that shows the sciagraphy image according to the sciagraphy picture signal of being read by sciagraphy image detection device 100.
Sciagraphy image detection device 100 has: sciagraphy visual detector 101; Signal detector 102, described signal detector 102 are used to detect the sciagraphy picture signal from 101 outputs of sciagraphy visual detector; Sweep signal control device 103, described sweep signal control device 103 is used for the scan line of output scanning signal to sciagraphy visual detector 101; And signal processing apparatus 104, described signal processing apparatus 104 obtains the detection signal that detected by signal detector 102 and they is outputed to display 200 as vision signal, and further control signal is outputed to sweep signal control device 103, signal detector 102 and the power supply unit 106 that will be described later.
Sciagraphy visual detector 101 is constructed such that a large amount of pixels is aligned to two dimensional form.Described pixel is made of following: imageing sensor portion 105, and it is made of bias electrode, semiconductor film and the charge collection electrode that will be described later; Charge storage capacitor 5, it is accumulated in the charge signal that is detected in the imageing sensor portion 105; And TFT switch 4, it is used for reading the electric charge that is accumulated in charge storage capacitor 5.In addition, be provided with scan line 2 and lot of data line 3 that a large amount of being used to opens and closes TFT switch 4, the electric charge that is accumulated in the charge storage capacitor 5 is read out by this data wire 3.
Sciagraphy image detection device 100 has variable C s power supply 106,106 pairs of preset time sections of this variable C s power supply change the electromotive force of charge storage capacitor electrode 14, this will be described later, and the charge storage capacitor 5 of each pixel of these charge storage capacitor electrode 14 structure sciagraphy visual detectors 101.Notice that variable C s power supply 106 is set on the peripheral substrate, this periphery substrate is different from and is independent of sciagraphy visual detector 101.
In this exemplary embodiments, variable C s power supply 106 is made of direct current (DC) voltage source 106a and switch 106b, as shown in Figure 1.By diverter switch 106b, charge storage capacitor 5 and GND () or DC power supply 106a link to each other, and for predetermined amount of time, the electromotive force that constitutes the charge storage capacitor electrode 14 of charge storage capacitor 5 is changed.
Variable C s power supply 106 is connected by Cs power control line 112 with signal processing apparatus 104.The control signal of switching the switch 106b of variable C s power supply 106 is outputed to Cs power control line 112 from signal processing apparatus 104.
This sciagraphy image detecting system is equipped with high voltage source 108, described high voltage source 108 bias electrode to imageing sensor portion 105 when being recorded in the sciagraphy image on the sciagraphy visual detector 101 applies high pressure, and this will be described later.Notice that although in this sciagraphy image detecting system, high voltage source 108 is independent of sciagraphy image detection device 100 and is provided with, high voltage source 108 can be included in the sciagraphy image detection device 100.In addition, " high pressure " means the voltage more than or equal to about 500V here.
Sciagraphy visual detector 101 will be described in more detail.Fig. 2 is the plane graph of structure that shows a pixel cell of sciagraphy visual detector 101, and Fig. 3 is the cutaway view along 3-3 line among Fig. 2.
As shown in Figure 3, in sciagraphy visual detector 101, the semiconductor film 106 of conduction electro-magnetic wave one after the other is formed on the active matrix substrate 10 with the bias electrode 7 that is connected to high voltage source 108.Semiconductor film 6 is because portion such as the irradiation of electromagnetic waves of X ray or analog and within it thereon produces electric charge (electronics-hole).Just, semiconductor film 6 is conduction electro-magnetic wave, and is used to by X ray image information is converted to charge information.In addition, for instance, semiconductor film 6 is formed by amorphous a-Se (amorphous selenium), and the main component of this amorphous a-Se is a selenium.Here, " main component " means the content that has more than or equal to 50%.
To specifically describe active matrix substrate 10 below.
Thin-film transistor (TFT) 4 is made of scan line 2, gate insulating film 15, data wire 3, connection electrode 13, channel layer 8, contact layer 9 etc.Charge storage capacitor (Cs) 5 is made of Cs electrode 14, gate insulating film 15, connection electrode 13 etc.
Channel layer (i layer) the 8th, the channel part of TFT switch 4, and be the current channel that connects data wire 3 and connection electrode 13.Contact layer (n
+Layer) 9 connect data wire 3 and connection electrode 13.
Insulating protective film 17 is formed on data wire 3 and the connection electrode 13,, is formed on the whole basically surface (whole basically zones) of covering on the glass substrate 1 that is.Like this, insulating protective film 17 is protected connection electrode 13 and data wires 3, and they are carried out electric insulation and isolation.In addition, insulating protective film 17 promptly, is positioned at the zone of facing on connection electrode 13 parts of Cs electrode 14 via gate insulating film 15 at its preposition, has contact hole 16.
Interlayer insulating film 12 by sensitization, form with TFT switch 4 electric insulations and the basic resin that separates.Contact hole 16 passes interlayer insulating film 12, thereby makes charge collection electrode 11 be connected to connection electrode 13.
The interlayer insulating film 12 of TFT switch 4 is set on the insulating protective film 17.Charge collection electrode 11 is set at the upper strata of interlayer insulating film 12, that is, and and in the superiors of active matrix substrate 10.Charge collection electrode 11 and TFT switch 4 are connected via connection electrode 13.
In addition, gate insulating film 15 is set on the Cs electrode 14, and connection electrode 13 is set on the gate insulating film 15.
High voltage source 108 (see figure 1)s are connected to bias electrode 7.Voltage is applied on the bias electrode 7 from high voltage source 108.Like this, via charge storage capacitor 5, between bias electrode 7 and charge collection electrode 11, produced electric field.At this moment, because semiconductor film 6 and charge storage capacitor 5 are configured to make it in series to be electrically connected, so when the radiation of passing the main body of taking pictures by when bias electrode 7 sides penetrate, at this moment, bias electrode 7 is in bias voltage and is applied to state on this bias electrode 7, and electric charge (electron-hole pair) produces in semiconductor film 6.The electronics that produces in semiconductor film 6 moves to positive electrode side, and move to negative electrode side in the hole, and the result to be electric charge be accumulated in the electrode holding capacitor 5.
Seeing on the whole of sciagraphy visual detector, a large amount of charge collection electrodes 11 are by two-dimensional arrangements, and the sciagraphy visual detector is provided with a large amount of charge storage capacitor 5 and a large amount of TFT switches 4, this charge storage capacitor 5 is connected to charge collection electrode 11 separately, and this TFT switch 4 is connected to charge storage capacitor 5 separately.Like this, the electromagnetic wave information that the charge information of two dimension can be by being accumulated in the two dimension in the charge storage capacitor 5 before and by the TFT switch 4 of continuous sweep, and easily read.
The equivalent electric circuit of a pixel that next will be by utilizing sciagraphy visual detector is as shown in Figure 4 described the TFT protective circuit.
As mentioned above, in this exemplary embodiments, charge collection electrode 11 is configured to make its channel part that covers TFT switch 4 via insulating protective film 17 and interlayer insulating film 12 (part that is formed by channel layer 8 and contact layer 9).By such structure, charge collection electrode 11 is used as second gate electrode about TFT switch 4, and the magnitude of current that flow to TFT raceway groove 4 can be controlled by the electromotive force of charge collection electrode 11.
Here, because charge collection electrode 11 is connected to the drain electrode (connection electrode 13) of TFT switch 4 via contact hole 16, charge collection electrode 11 is used as diode.Therefore, as equivalent electric circuit, exist wherein diode D as shown in Figure 4 to be parallel to TFT switch 4 and the structure of setting.
When radiation irradiation on semiconductor layer 6 and electric charge is produced and charge-trapping when the electromotive force Vp of charge collection electrode 11 places and charge collection electrode 11 becomes more than or equal to set-point, diode D connects and is accumulated in the flow of charge data wire 3 in the charge storage capacitor 5.Like this, because the irradiation of radiation when making that a large amount of electric charges is produced, before TFT switch 4 or charge storage capacitor 5 were disconnected by static, electric charge can be lowered by the electromotive force Vp that diode D flows to data wire 3 and charge collection electrode 11.
Next, will be described in the leakage current characteristic of TFT switch 4 under the situation that aforesaid TFT protective circuit is not set at TFT switch 4, and under the situation that is provided with the TFT protective circuit leakage current characteristic of TFT switch 4.Do not have at TFT switch 4 under the situation of TFT protective circuit, as shown in Figure 5, the leakage current Ioff of TFT switch 4 is along with dull the increasing near electrical source voltage of the electromotive force Vp of charge collection electrode.On the other hand, have at TFT switch 4 under the situation of TFT protective circuit, as shown in Figure 6, when the electromotive force Vp of charge collection electrode surpassed given voltage (being about 30V) here, as the diode operation of TFT protective circuit, leakage current is index to be increased.Like this, compare with the situation that does not have the TFT protective circuit, a large amount of leakage currents can flow out, and the result is easily to prevent the electrostatic breakdown to TFT switch and charge storage capacitor.
In addition, in this exemplary embodiments, variable C s power supply 106 is provided with as shown in Figure 1.Yet, as shown in Figure 7, the DC power supply 106a of variable C s power supply 106 can also only be set in signal processing apparatus 104, and the switch 106b of variable C s power supply 106 is merged among the amplifier IC107, described amplifier IC107 is equipped with a large amount of signal detector (amplifier) 102.By switch 106 is merged among the amplifier IC107, the distance between switch 106b and the sciagraphy visual detector 101 can be shortened, and the noise that is produced by the path circuit can be lowered.In addition, by switch 106b is merged among the amplifier IC107, the switch on the peripheral electrode substrate becomes unnecessary, and the surface area of peripheral circuit can be reduced, and can become compact.Notice that signal processing apparatus 104 is connected by Cs power control line 112 with amplifier IC 107, and the control signal of the switch 106b of switching variable C s power supply 106 is outputed to Cs power control line 112 from signal processing apparatus 104.
Next will utilize Fig. 8 to explain driving method for the sciagraphy visual detector that reduces the TFT leakage current, wherein reducing the TFT leakage current is feature of the present invention.Fig. 8 show the irradiation that is radiated at the radiation on the sciagraphy visual detector 101 time signal, control TFT switch 4 opening/closing and by from the sweep signal of sweep signal control device 103 outputs, be applied to the bias voltage of charge storage capacitor 5 and by signal detector 102 detected sensed current by variable C s power supply 106.
At first, in write cycle time, radiation is irradiated on the sciagraphy visual detector 101.In this write cycle time, the Cs electrode 14 that constitutes charge storage capacitor is maintained at the electromotive force identical with GND.Subsequently, in the write cycle time process, the electromotive force Vp of charge collection electrode 11 increases according to the amount of radiation of being shone.For instance, in Fig. 6, when Vp25V, approximately the leakage current of 10pA flows out to holding wire 3 via TFT switch 14.
Subsequently, as described in Figure 8, leakage current finishes after write cycle time.Yet, owing to the electromotive force Vp of charge collection electrode also reveals when descending, so leakage current reduces in time gradually.Subsequently, in this exemplary embodiments, for the leakage current that reduces slowly to flow, in the time period of read cycle, the Cs power switch signal is outputed to variable C s power supply 106 from signal processing apparatus 104 after write cycle time finishes.The switch 106b of described variable C s power supply is switched according to this signal, and the electromotive force Vcs of the Cs electrode 14 of charge storage capacitor 5 is by 106 superchargings of variable C s power supply, and for the given time period, the electromotive force Vp of charge collection electrode thereby be maintained at a high position.Notice that " supercharging " means that here the voltage that is applied to Cs electrode 14 is configured to the high potential more than or equal to predetermined value.In addition, this predetermined value preferably is configured to the magnitude of voltage of the breakover point (beginning to be index at this as the diode operation of TFT protective circuit and leakage current increases) more than or equal to as described in Figure 6 leakage current characteristic.
For instance, also become under the situation of 35V owing to Vcs at Vp rising 10V, the leakage current of 100pA is to data wire.Above-mentioned voltage hold period preferably is guaranteed.Become about 30 to 25V from 4 outflows of TFT switch and Vp fully up to electric charge.With regard to the time, the voltage hold period preferably is set between 100 μ s to 1s, and more preferably is about 100ms.If the voltage hold period is too short, then leakage current can not fully flow out, and if the voltage hold period is oversize, then the time point that begins of read cycle becomes very evening, and operating efficiency is worsened.
After voltage was applied to charge storage capacitor 5 as mentioned above, when the Cs of charge storage capacitor 5 electrode 14 was connected to GND and Vcs and turns back to its initial value, Vp reduced 10V, and becomes about 15 to 20V thus.At this moment leakage current drops to about a few pA.Be applied to the Cs electrode 14 voltage Vcs of charge storage capacitor 5 by such change, leakage current can be reduced.
Next, sweep signal is outputed to scan line G1, G2, G3 in succession from sweep signal control device 103.The TFT switch 4 that is connected to scan line G1, G2, G3 is opened in succession, and the electric charge that is accumulated in the charge storage capacitor 5 flows out to data wire 3.The electric charge that flows out to data wire 3 is detected by signal detector 102, and reads.
Be used for being illustrated at Figure 10 in the high-level schematic functional block diagram of all time executive control operations as shown in Figure 8.The time Be Controlled of the irradiation of supercharging Cs electrode 14, image detection (image reads) and radiation is so that it was performed in all time as shown in Figure 8.
Particularly, be included in the control of all operations as shown in Figure 8 of time control part f1 execution in the signal processing apparatus 104.When carries out image detected, at first, control signal S1 was outputed to unshowned radiation source from time control part f1, and radiation f2 was controlled by this control signal S1 by the time on from radiation source irradiates to sciagraphy visual detector 101.
Next, control signal S2 is outputed to variable C s power supply 106 via Cs power control line 112 from time control part f1.The switch 106b of variable C s power supply 106 is switched to DC power supply 106a side, and the time of variable C s power supply supercharging f3 is controlled.
Subsequently, after variable C s power supply supercharging f3, control signal S3 is outputed to sweep signal control device 103, signal detector 102 etc. from time control part f1.Time to the detection f4 that is recorded in the image in the sciagraphy visual detector 101 is controlled according to this control signal S3.
Notice that for instance, the time, control part f1 can realize by program, the calculation element such as CPU, DSP etc. that described program is included in the signal processing apparatus 104 is carried out.
As mentioned above, according to the driving method of this exemplary embodiments, view data before the read cycle leakage current fully mobile, and leakage current is fully reduced in the process of view data read cycle, and thereafter, view data reads and is performed.Thereby leakage current effects can be restrained in the read cycle process.Notice that in the read cycle process, the electromotive force of the Cs electrode 14 of the electromotive force of the reference electrode line 102a (see figure 4) of signal detector 102 and formation charge storage capacitor 5 is set at identical level.When the pixel of sciagraphy visual detector was provided with as described in Figure 4, the electromotive force of the Cs electrode 14 of the electromotive force of the reference electrode line 102a of signal detector 102 and formation charge storage capacitor 5 was GND.GND can realize stable by aforesaid reference electrode line 102a is linked to each other with Cs electrode 14.
For sake of comparison, figure 9 illustrates the conventional ADS driving method of sciagraphy visual detector.
At first, in write cycle time, radiation is irradiated onto on the sciagraphy visual detector.In this write cycle time, the Cs electrode 14 that constitutes charge storage capacitor is maintained at the electromotive force identical with GND.Subsequently, in the write cycle time process, the electromotive force Vp of charge collection electrode 11 increases according to the amount of radiation of being shone.The electric charge that becomes superfluous owing to the increase of the electromotive force of charge collection electrode 11 spills via TFT switch 4.Thus, the electromotive force Vp of charge collection electrode 11 reduces, thereby and, leakage current also reduces gradually.Yet, as shown in Figure 9, compare with sciagraphy visual detector driving method of the present invention, need long time.
Next, the sweep signal from sweep signal control device 103 is outputed to scan line G1, G2, G3 in succession.The TFT switch 4 that is connected to scan line G1, G2, G3 is opened in succession.The electric charge that is accumulated in the charge storage capacitor 5 flows out to data wire 3.The electric charge that flows out to data wire 3 is detected by signal detector 102, and reads.Yet, in this conventional ADS driving method, as mentioned above, in order to make leakage current need reduce long time.Therefore, in the read cycle of view data, be increased, and to form easily be not the Vitua limage (artificial product) that is caused by the data that write corresponding to the amount of the electric charge of leakage current.
Notice that in the sciagraphy visual detector of aforesaid exemplary embodiments, the TFT protective circuit is arranged on TFT switch 4 as mentioned above.Yet the TFT protective circuit is not to be provided with.To aforesaid predetermined amount of time, as long as by apply the effect that voltage just can obtain to reduce leakage current to charge storage capacitor.
In addition, in the sciagraphy image detection device of aforesaid exemplary embodiments, positive voltage is applied to charge storage capacitor.Yet, have at the sciagraphy visual detector under the situation of back bias voltage, need to apply negative voltage.Just, the direction that need increase along the leakage current from TFT switch 4 applies voltage.
Next sciagraphy image detecting system about second exemplary embodiments will be described.
Similar about the general configuration of the sciagraphy image detecting system of second exemplary embodiments to the sciagraphy image detecting system of first exemplary embodiments shown in Figure 1.Yet the structure of the variable C s power supply in this sciagraphy image detecting system is different with structure in first exemplary embodiments.
As shown in figure 11, the voltage of the 113 output square wave shapes of the variable C s power supply in the sciagraphy image detecting system of second exemplary embodiments.In addition, control signal is outputed to variable C s power supply 113 from signal processing apparatus 104, and according to this control signal, in the time shown in Fig. 8, the voltage of square wave shape is exported from variable C s power supply 113.Notice that in this exemplary embodiments, the voltage of square wave shape is exported from variable C s power supply 113, but waveform is not limited thereto.Can use waveform arbitrarily, as long as this waveform can supercharging predetermined value or more.For instance, can use the voltage drift (mountain-shaped voltage shift) of chevron.
The equivalent circuit diagram of a pixel of the sciagraphy visual detector of second exemplary embodiments is illustrated in Figure 12.
Variable C s power supply 113 can be set on the peripheral circuit substrate, and described peripheral circuit substrate is independent of sciagraphy visual detector 101 and is provided with, and perhaps can be set on the sciagraphy visual detector 101.
In the sciagraphy image detecting system of first exemplary embodiments,, when diverter switch, produce switching noise because variable C s power supply 106 is made of dc voltage source and switch.Yet,, can eliminate this switching noise by only constructing as the variable C s power supply 113 in this exemplary embodiments by voltage source.
The structure of the sciagraphy image detecting system of other structure and operation and first exemplary embodiments and class of operation are seemingly.
Next sciagraphy image detecting system about the 3rd exemplary embodiments will be described.
Because about the similar of the sciagraphy image detecting system of the structure of the sciagraphy image detecting system of the 3rd exemplary embodiments and first exemplary embodiments, so will omit specific descriptions to this structure.
Next, will utilize Figure 16 to describe driving method about the sciagraphy image detecting system of this exemplary embodiments.Figure 16 shows the opening/closing of the time signal of radiation irradiation to the sciagraphy visual detector 101, control TFT switch 4 and by from the sweep signal of sweep signal control device 103 outputs, be applied to the bias voltage of charge storage capacitor 5 and by signal detector 102 detected detection electric currents by variable C s power supply 106.
At first, in image detection device of the present invention, when image detection is performed, the Cs power switch signal from signal processing apparatus 104 to the output of variable C s power supply 106 before write cycle time.Switch 106b is switched by this signal, thereby makes voltage be applied to Cs electrode 14 from dc voltage source 106a, and the Cs electrode 14 of charge storage capacitor 5 is supercharged to electromotive force Vcs.
Subsequently, in write cycle time, radiation is irradiated to sciagraphy visual detector 101.In this write cycle time, the Cs electrode 14 that constitutes holding capacitor is maintained at electromotive force Vcs.
In the write cycle time process, with the electromotive force Vcs of Cs electrode 14 as a reference, the electromotive force Vp of charge collection electrode 11 increases according to the amount of radiation of being shone.For instance, if the electromotive force Vcs of Cs electrode 14 be 10V and under with the electromotive force Vcs situation as a reference of Cs electrode 14 electromotive force Vp be 25V, then in fact, the electromotive force Vcs of Cs electrode 14 is 35V.
As shown in Figure 6, the leakage current of 100pA flows to data wire 3 according to the electromotive force of the electromotive force Vcs of Cs electrode 14 via TFT switch 4.
Subsequently, the predetermined amount of time after write cycle time finishes was after the past, and the Cs power switch signal is stopped from the output of signal processing apparatus 104 to variable C s power supply 106.In this way, the switch 106b of variable C s power supply is switched, and the Cs electrode 14 of charge storage capacitor 5 is connected to GND, and the electromotive force Vp of charge collection electrode 11 gets back to the electromotive force based on GND.Like this, Vp reduces 10V, becomes 15 to 20V.At this moment, leakage current reduces about a few pA.By utilizing this mode to change to be applied to the voltage Vcs of the Cs electrode 14 of charge storage capacitor 5, leakage current can be reduced.
Next, sweep signal is outputed to scan line G1, G2, G3 in succession from sweep signal control device 103.The TFT switch 4 that is connected to scan line G1, G2, G3 is opened in succession, and the electric charge that is accumulated in the charge storage capacitor 5 flows out to data wire 3.The electric charge that flows out to data wire 3 is detected by signal detector 102, and reads.
Like this, according to the driving method of this exemplary embodiments, as mentioned above, before the read cycle, leakage current is fully mobile in view data, and is fully reduced at the time of view data read cycle leakage current, and thereafter, view data reads and is performed.Thereby in the read cycle process, the effect of leakage current can be suppressed.
Like this, according to the driving method of this exemplary embodiments, can be shortened in the time that after write cycle time, begins up to the read cycle.
Just, for the electric charge that is accumulated is read with being stabilized, need the given time period from write cycle time to electromotive force supercharging (for example, about 10ms) from each pixel of sciagraphy visual detector 101 to Cs electrode 14.This is because if the electromotive force of Cs electrode 14 is pressurized, then have such worry in the process of x-ray bombardment: the electromotive force Vp of charge collection electrode 11 will uprise suddenly and TFT switch 4 will turn-off.Therefore, needing the supercharging to carry out the time enough allowance from write cycle time to electromotive force to Cs electrode 14.
In addition, as mentioned above, fully mobile in order to make leakage current, voltage hold-time is preferably about 100ms.
Therefore, as shown in Figure 8, when leakage current is configured to write cycle time independence deenergized period, there is one long period before can carrying out in the read cycle.
Therefore, as shown in figure 16, by the electromotive force of Cs electrode 14 being carried out supercharging in the preset time section, can reduce aforesaid argin etc., and the time that begins from the write cycle time to the read cycle can be shortened, described predetermined amount of time comprises that the electromagnetic wave that is used to write down is by the time period of radiation (that is write cycle time).
Note, utilize the mode identical with first exemplary embodiments, in the aforesaid read cycle, preferably the electromotive force of the reference electrode line 102a (see figure 4) of signal detector 102 and the electromotive force that constitutes the Cs electrode 14 of charge storage capacitor 5 are arranged to identical level.
Next, with the principle of the less leakage current that illustrated above describing.
The initial existence of the protection diode of TFT protective circuit is in order to protect the TFT switch to avoid puncture voltage.Yet, in fact,, also exist and reduce by the caused anti noise of leakage current by the protection diode is provided.If the threshold voltage of protection diode can be optimised, then can be reduced by the caused noise of leakage current.
Utilize the protection diode to reduce to utilize Figure 13 A and Figure 13 B to specifically describe by the mechanism of the caused noise of leakage current.Figure 13 A is the figure that is used to explain the leakage current under the situation of not protecting diode; And Figure 13 B is the figure that is used to explain the leakage current under the situation that the protection diode is arranged.Figure 13 A and Figure 13 B show the example that four detecting elements (pixel) are connected to a data wire 20.
When X ray was taken pictures, X ray shone on the sciagraphy visual detector from x-ray source uniformly.The target of taking pictures is placed between x-ray source and the sciagraphy visual detector, and this target is the X ray absorber such as human body etc.The sciagraphy visual detector detects and passes X ray absorber and weakened X ray.At first, consider the situation of the structure shown in Figure 13 A, wherein do not protect diode among the detecting element P1 in Figure 13 A, for instance, the transmissivity of X ray absorber is 0.1%.Therefore, only there is 0.1mR to shine on the detecting element in the X ray of 100mR.Thus, electric charge produces on semiconductor layer, and quantity of electric charge Qp is accumulated in the electrode passive electrode.Here, if the charge conversion efficient of semiconductor layer is 6pC/mR, then Qp is 0.6pC.Further, if the charge storage capacitance Cp of detecting element is 1pF, then the electromotive force Vp of charge collection electrode is 0.6V.According to Fig. 5, leakage current Ioff at this moment is less than or equal to 1fA (being less than or equal to measuring limit).
On the other hand, on the detecting element (the detecting element P2 among Figure 13 A) of the transmission part that does not have photo-object, Qp=60pC, and Vp=60V, and leakage current reaches 230 μ A.Because leakage current is the electric current that flows when the operation of TFT switch is closed, so when obtaining the view data of predetermined detection element, all leakage currents that are connected to the detecting element of data wire 20 are used as the leakage current noise and give.Therefore, exist when maintaining the detecting element of a large amount of stored charges in the detecting element that is connected to the identical data line, its influence is big especially.
On the other hand, having the structure shown in Figure 13 B that protects diode is considered.On the detecting element (the detecting element P2 among Figure 13 B) of the transmission part that does not have photo-object, provisionally, Qp=60pC and Vp=60V.Yet simultaneously, the protection diode activates, and unnecessary electric charge is drained to data wire 20.The maximum leakage current flow that surpasses 10nA is passed the protection diode, and the quantity of electric charge that is accumulated reduces.The result is, the electromotive force of charge collection electrode drops near the protection diode drive threshold voltage of 25V, and, thereby magnitude of leakage current also reduces to 10 μ A.After fully carrying out, carry out reading of view data by the leakage of protection diode.Therefore, the leakage current of protection diode can not have contribution to the leakage current noise.Like this, because becoming, the noise that leakage current causes is less than or equal to 1/20 when not having the TFT protective circuit.
Have a lot of examples, the magnitude of current of wherein above-mentioned protection diode is not enough to reach the target that reduces the leakage current noise.Further, the amount of radiation required as X ray information normally is less than or equal to 10mR, although they are different along with the difference of goal systems.If the threshold voltage of TFT protective circuit can be lowered, then the leakage current noise can be further reduced and picture quality can improve.
These problems can the application of the invention sciagraphy image detection device and sciagraphy visual detector driving method overcome.
As mentioned above, as shown in figure 14, the electromotive force Vcs of charge storage capacitor is pressurized, and because this, for the given time period, the electromotive force Vp of charge collection electrode is maintained on the numerical value of high 10V.Just, on the detecting element (the detecting element P2 among Figure 14) of transmission part, because the x-ray bombardment of 100mR, provisionally, Qp=60pC and Vp=60V, but because protected diode and Vcs supercharging, unnecessary electric charge is escaped to data wire 20.The result is near the threshold voltage of the electromotive force of the charge collection electrode protection diode that drops on 25V.Therefore, up to reads image data, Vp is just returned to its initial condition by Vcs.Therefore, the electromotive force of charge collection electrode is lowered to about 15V, and the result is, the amount of leakage current reduces to 1.6 μ A.In mode same as described above, after fully being carried out, carry out reading of view data by spilling of protection diode.Therefore, the leakage current of protection diode does not contribute to the leakage current noise.
The first and the 3rd top exemplary embodiments has been described the situation of using direct conversion hysteria sciagraphy visual detector 101, and wherein, radiation directly is converted to electric charge on semiconductor film 6 and this electric charge is accumulated.Yet, the present invention is not limited only to this, but can be applied in the non-direct conversion hysteria sciagraphy visual detector, wherein radiation is once converted to light in CsI:Tl, GOS (Gd2O2S:Tb) or similar scintillator, and this light of changing is converted into electric charge at semiconductor layer 6, and this electric charge is accumulated.Especially, in direct conversion hysteria detector, semiconductor film 6 must be set to thicker so that directly convert radiation to electric charge, and compare with non-direct conversion hysteria detector, higher voltage is applied to bias electrode 7 from high-voltage power supply 108, thereby easier appearance owing to leakage current goes wrong.Therefore, by using above-mentioned first and the driving method of the 3rd exemplary embodiments, the effect of leakage current can be suppressed.Note, under the situation of non-direct conversion hysteria detector, exist radiation scintillator be converted into light, and the light changed of institute be converted into the structure of electric charge at semiconductor layer 6.Thereby, to compare with the situation of direct conversion hysteria detector, semiconductor film 6 can be configured to approach, and electric charge can be accumulated on the charge collection electrode 11 and charge storage capacitor 5 need not be set.Yet, there is such situation, wherein electric capacity is provided with wittingly so that increase the quantity of electric charge that can be accumulated.Be arranged on auxiliary capacitor, parasitic capacitance or stray capacitance in the non-direct conversion hysteria detector by this way wittingly corresponding to holding capacitor of the present invention.
The above-mentioned first and the 3rd exemplary embodiments has been described the example of the view data that reads an image.Yet as shown in figure 17, by repeatedly and continuously carrying out radiation irradiation to sciagraphy visual detector 101 and from sciagraphy visual detector 101 reads image data, mobile image also can be obtained.As mentioned above, can be shortened owing to leakage current in the driving method of the first and the 3rd above-mentioned exemplary embodiments reduces the shared time, these driving methods are suitable for the image of capture movement.
Further, have a kind of photographic method as follows: the sciagraphy image is taken at least twice continuously, changes the amount of radiation (energy) of the X ray that is shone simultaneously.Can be by on each of the image that obtains by taking pictures, carrying out such as the image processing that image is applied suitable weight and calculating because the difference of the variation of the absorption coefficient that amount of radiation causes comes described difference is carried out composition.For instance, the image of bone can be removed from the image of taking chest region, or the like.Like this, the image that is difficult to visual identity by the single shot acquisition.
The prerequisite of this image pickup method is that the target of taking does not move, so image must be obtained in short as far as possible shooting interval.
For instance, Figure 18 is the example of the shooting that reduces of twice and energy, and wherein high-octane shooting is being performed for the first time, and low-energy shooting is being performed for the second time.
As shown in figure 18, in the write cycle time process when taking for the first time, voltage is applied to Cs electrode 14 from dc voltage source 106a, and Cs electrode 14 is maintained at electromotive force Vcs.Thereby can shorten leakage current and reduce the shared time, and thus, can shorten to the time before taking for the second time.Notice that under the very little situation of the amount of knowing the leakage current that is produced in advance, the voltage from dc voltage source 106a to Cs electrode 14 applies and can be eliminated.In Figure 18, be low-yield shooting for the second time, and the leakage current that is produced is very little.Therefore, voltage is not applied to Cs electrode 14 from dc voltage source 106a.Like this, can be accelerated by the read cycle of taking the view data of being obtained for the second time.
Claims (19)
1. image detection device comprises:
Visual detector, described visual detector is equipped with test section, described test section has charge generation portion, holding capacitor and thin film transistor switch element, described charge generation portion receives the electromagenetic wave radiation that is used to write down and produces electric charge, two electrodes are set in the described holding capacitor with toward each other, this holding capacitor is accumulated in the electric charge that described charge generation portion is produced, and in this holding capacitor, according to the quantity of electric charge that is accumulated, electromotive force about as a reference an electrode, the electromotive force of another electrode changes thereupon, and described thin film transistor switch element is used for reading the electric charge that is accumulated in described holding capacitor;
Power supply unit, described power supply unit are connected so that can be to a described electrode application voltage; And
Control part, described control part control imposes on the voltage of a described electrode from power supply unit, by the predetermined amount of time before from described visual detector, reading, promote flowing with the electric charge in being accumulated in described holding capacitor from the leakage current of switch element.
2. image detection device according to claim 1, wherein, described control part is controlled and is made described voltage be applied to a described electrode at described predetermined amount of time, and wherein said predetermined amount of time is for being read the time period before up to described electric charge from described visual detector after the electromagnetic wave that is used to write down is irradiated on the described visual detector.
3. image detection device according to claim 1, wherein, described control part control make described voltage at the fixed time the section be applied to a described electrode, described predetermined amount of time comprises that the electromagnetic wave that is used to write down is irradiated to the time period that is continued on the described visual detector.
4. image detection device according to claim 1, wherein, described switch element is configured such that, when electric charge is accumulated in the described holding capacitor and the electromotive force of described another electrode when becoming more than or equal to set-point, electric current flows.
5. image detection device according to claim 1, wherein, described power supply unit is set on the peripheral circuit substrate, and described peripheral circuit substrate is provided with separately with described visual detector.
6. image detection device according to claim 1, also comprise signal detector, described signal detector detects the quantity of electric charge that is accumulated by the electromotive force that detects the charge signal of reading from the test section of described visual detector, wherein, when detecting the electromotive force of described charge signal, the electromotive force of reference electrode line is identical potential level with the electromotive force of a described electrode of a part that constitutes described holding capacitor, and described reference electrode line is the reference that described signal detector detects.
7. image detection device according to claim 1, wherein, described predetermined amount of time is to 1s from 100 μ s.
8. image detection device comprises:
Visual detector, described visual detector is equipped with test section, described test section has charge generation portion, holding capacitor and thin film transistor switch element, described charge generation portion receives the electromagenetic wave radiation that is used to write down and produces electric charge, two electrodes are set in the described holding capacitor with toward each other, this holding capacitor is accumulated in the electric charge that described charge generation portion is produced, and in this holding capacitor, according to the quantity of electric charge that is accumulated, electromotive force about as a reference an electrode, the electromotive force of another electrode changes thereupon, and described thin film transistor switch element is used for reading the electric charge that is accumulated in described holding capacitor; And
Voltage applying circuit, the electric charge in being accumulated in described holding capacitor are carried out voltage by described voltage applying circuit to a described electrode and apply by the predetermined amount of time before reading from described visual detector; Described voltage applying circuit applies controlled voltage to a described electrode, to change the leakage current from described switch element.
9. image detection device according to claim 8, wherein, described predetermined amount of time is the time period after the electromagnetic wave that is used to write down is irradiated on the described visual detector.
10. image detection device according to claim 8, wherein, described predetermined amount of time comprises that the electromagnetic wave that is used to write down is irradiated to the time period that is continued on the described visual detector.
11. image detection device according to claim 7, wherein, described switch element is configured such that, when electric charge is accumulated in the described holding capacitor and the electromotive force of described another electrode when becoming more than or equal to set-point, electric current flows.
12. image detection device according to claim 7, wherein, described voltage applying circuit is set on the peripheral circuit substrate, and described peripheral circuit substrate is provided with separately with described visual detector.
13. image detection device according to claim 7, also comprise signal detector, described signal detector detects the quantity of electric charge that is accumulated by the electromotive force that detects the charge signal of reading from the test section of described visual detector, wherein, when detecting the electromotive force of described charge signal, the electromotive force of reference electrode line is identical potential level with the electromotive force of a described electrode of a part that constitutes described holding capacitor, and described reference electrode line is the reference that described signal detector detects.
14. image detection device according to claim 7, wherein, described predetermined amount of time is to 1s from 100 μ s.
15. image detection device according to claim 7, wherein, described voltage applying circuit is configured such that the voltage that can export the square wave shape.
16. method that drives visual detector, described visual detector is equipped with test section, described test section has charge generation portion, holding capacitor and thin film transistor switch element, described charge generation portion receives the electromagenetic wave radiation that is used to write down and produces electric charge, two electrodes are set in the described holding capacitor with toward each other, this holding capacitor is accumulated in the electric charge that described charge generation portion is produced, and in this holding capacitor, according to the quantity of electric charge that is accumulated, electromotive force about as a reference an electrode, the electromotive force of another electrode changes thereupon, described thin film transistor switch element is used for reading the electric charge that is accumulated in described holding capacitor, and described method comprises step:
The electromagnetic wave that generation is used to write down, and with this electromagnetic wave irradiation to described charge generation portion;
In the predetermined amount of time before the time point of from described holding capacitor, reading electric charge via described switch element, change the voltage that is applied to a described electrode, to promote leakage current from described switch element; And
Operate described switch element and detect the electric charge that is accumulated in the described holding capacitor.
17. the method for driving visual detector according to claim 16, wherein, described predetermined amount of time is the time period after the electromagnetic wave that is used to write down is irradiated on the described visual detector.
18. the method for driving visual detector according to claim 16, wherein, described predetermined amount of time comprises that the electromagnetic wave that is used to write down is irradiated to the time period that is continued on the described visual detector.
19. the method for driving visual detector according to claim 16, wherein, described switch element is configured such that, when electric charge is accumulated in the described holding capacitor and the electromotive force of described another electrode when becoming more than or equal to set-point, electric current flows.
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| JP2008-021612 | 2008-01-31 | ||
| JP2008021612 | 2008-01-31 | ||
| JP2008021612A JP5020840B2 (en) | 2007-06-26 | 2008-01-31 | Image detection apparatus and image detector driving method |
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| JP2011242261A (en) * | 2010-05-18 | 2011-12-01 | Fujifilm Corp | Radiation detector |
| JP6385187B2 (en) * | 2014-07-31 | 2018-09-05 | キヤノン株式会社 | Photoelectric conversion device, photoelectric conversion system |
| EP3565238B1 (en) * | 2016-12-27 | 2023-07-19 | Panasonic Intellectual Property Management Co., Ltd. | Imaging device, camera and imaging method |
| JP6884064B2 (en) | 2017-07-26 | 2021-06-09 | キヤノン株式会社 | Imaging device and its control method, program, storage medium |
| EP3567405A1 (en) * | 2018-05-08 | 2019-11-13 | Koninklijke Philips N.V. | Photon counting spectral ct |
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| JPH10170658A (en) * | 1996-12-06 | 1998-06-26 | Toshiba Corp | X-ray image pick-up device |
| JP3489782B2 (en) * | 1999-02-24 | 2004-01-26 | 株式会社東芝 | X-ray imaging device |
| JP3624165B2 (en) * | 2000-03-31 | 2005-03-02 | キヤノン株式会社 | Electromagnetic wave detection device |
| JP2002314754A (en) * | 2001-04-09 | 2002-10-25 | Canon Inc | Photoelectric conversion device |
| JP2002350551A (en) * | 2001-05-25 | 2002-12-04 | Canon Inc | Radiation imaging apparatus and radiation imaging system using the same |
| JP2005012049A (en) * | 2003-06-20 | 2005-01-13 | Shimadzu Corp | Radiation detector and radiation imaging apparatus including the same |
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