CN1883191A - Photoelectric converting apparatus - Google Patents
Photoelectric converting apparatus Download PDFInfo
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- CN1883191A CN1883191A CN200480034016.9A CN200480034016A CN1883191A CN 1883191 A CN1883191 A CN 1883191A CN 200480034016 A CN200480034016 A CN 200480034016A CN 1883191 A CN1883191 A CN 1883191A
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Abstract
A photoelectric converting apparatus of the present invention includes a photoelectric converting element, a resetting transistor in which a source is connected to the photoelectric converting element and a drain is connected to a resetting power source, a readout transistor in which a gate is connected to the photoelectric converting element and a drain is connected to a readout power source, a signal line connected to a source of the readout transistor, a selecting transistor connected between the readout power source or the signal line and the readout transistor, and a constant current source connected to the signal line.
Description
Technical field
The present invention relates to the photoelectric conversion device such as radiation image pickup equipment, particularly, relate to being designed for and reduce the photoelectric conversion device that the sensitivity that caused by parasitic capacitance descends.
Background technology
By arrive the transmission of electric capacity by matrix driving, read the photoelectric conversion device of the electric charge that obtains by the opto-electronic conversion in the photo-electric conversion element of the sensor array that utilizes amorphous silicon or polysilicon, known such as radioactive ray (radiation) image pick up equipment.
Fig. 9 is the schematic circuit diagram of the existing photoelectric conversion device of expression (radiation image pickup equipment).In existing photoelectric conversion device, as shown in Figure 9, the pixel of being indicated by frame of broken lines comprises PIN photodiode PD and selection thin-film transistor (TFT) ST, and such pixel is by two-dimensional arrangements, thus formation sensor array 101.Such device for example is made of amorphous silicon layer that forms on glass substrate 102 and polysilicon layer.The PIN diode PD of pixel is at the bias voltage Vs of its public electrode reception from power supply.
In addition, the grid of the selection TFT ST of pixel is connected with common gate polar curve Vg1-VgM.Common gate polar curve Vg1-VgM is connected with the gate drivers 104 with shift register (not shown).The source electrode of the selection TFT ST of pixel is connected with common signal line Sig1-SigN.Common signal line Sig1-SigN is connected with the reading circuit 103 with amplifier Amp1-AmpN, analog multiplexer MUX and A/D converter (not shown).
The existing photoelectric conversion device of this structure is carried out matrix driving by gate drivers 104, thereby shot image data is exported to reading circuit 103 and is read out.
Below, will illustrate at existing photoelectric conversion device, such as the cross-sectional structure of the sensor array that adopts in the radiation image pickup equipment.Figure 10 is the cross-sectional view of the pixel of the existing photoelectric conversion device of expression (radioscopic image pick device).
On glass substrate 201, in each pixel (pixel), stacked grid layer (lower electrode) 202, insulating barrier (amorphous silicon nitride films) 203, amorphous silicon semiconductor layer 204, amorphous n-silicon layer 205 and source (upper electrode) 206 are selected thin-film transistor (TFT) 222 thereby constitute.Equally on glass substrate, the extension of stacked source 206 (lower electrode), amorphous p-silicon layer 207, amorphous silicon semiconductor layer 208, amorphous n-silicon layer 209 and top electrode layer 210, thus constitute photodiode 221.In addition, on glass substrate 201, there are amorphous silicon semiconductor layer 204, the wiring portion 223 that amorphous n-silicon layer 205 and source 206 constitute by stacked insulating barrier 203.In addition, for example the protective layer 211 that is made of amorphous silicon nitride films is formed like this, so that cover these assemblies, luminescent coating 213 is bonded on the protective layer 211 by adhesive linkage 212.For example, this structure has been described in Japanese Patent Application Publication No.H08-116044.
Luminescent coating 213 is used for radioactive ray (X ray) are converted to visible light.Usually, the photodiode that is formed by amorphous silicon is extremely low to the sensitivity of X ray.Luminescent coating 213 is made of for example gadolinium sill or CsI (cesium iodide).
In this existing photoelectric conversion device (radioscopic image pick device), in the time of in entering luminescent coating, the X ray that sees through object is converted into visible light.Visible light enters photodiode subsequently.Photodiode produces electric charge in semiconductor layer, when TFT was switched on, such electric charge was transferred to reading circuit continuously and is read out.
But, in the existing photoelectric conversion device such as radiation image pickup equipment, when the number of the pixel of two-dimensional arrangements increases, in common signal line, produce big parasitic capacitance, thereby cause output voltage significantly to reduce.More particularly, as shown in Figure 9, have parasitic capacitance Cgs between the grid of selecting TFT ST and source electrode, the value of the parasitic capacitance relevant with common signal line increases pro rata with the number of the pixel that is connected with such common signal line.For example, passing through vertically to arrange 2000 200 * 200 microns pixel and transversely arranged 2000 200 * 200 microns pixel, the parasitic capacitance Cgs of the 0.05pF in position prepares under the situation of the area sensor corresponding, even also can cause the parasitic capacitance of every common signal line 0.05 * 2000=100pF with the X-ray film that is of a size of 40 * 40 centimetres.
On the other hand, photodiode PD has the sensor capacitance C of about 1pF.So, the signal voltage V1 that entering of responding to visible light produced in photodiode, observable output voltage V o becomes Vo=V1 * Cs/ (Cs+Cgs) * 2000 on common signal line, thereby output Vo becomes about 1/100 of signal voltage V1.
So because this remarkable loss of output voltage, existing photoelectric conversion device can not be constituted as large-area transducer such as radiation image pickup equipment.In addition, because this remarkable loss of output voltage, this equipment is subject to the noise that produces and the influence of external noise in the amplifier of reading circuit, thereby, be difficult to constitute highly sensitive photoelectric conversion device.By constant-current supply or low noise amplifier are provided to reading circuit, can reduce this The noise, still, can cause the shortcoming that increases such as cost as this low noise amplifier of special circuit.In addition, because this low noise amplifier has high electrical power consumed usually, so reading circuit can cause very important heating.
Summary of the invention
The purpose of this invention is to provide and a kind ofly can reduce the The noise that produces by parasitic capacitance, and the photoelectric conversion device that reads of available reading circuit with simple structure of low electrical power consumed.
As the result of the thoroughgoing and painstaking research that solves above-mentioned shortcoming, the inventor has realized the present invention in the following embodiments.
Photoelectric conversion device of the present invention is characterised in that and comprises photo-electric conversion element, reset transistor, source electrode is connected with photo-electric conversion element in this transistor, drain electrode is connected with reset power, reads transistor, and grid is connected with photo-electric conversion element in this transistor, drain electrode with read power supply and be connected, with read the holding wire that transistorized source electrode is connected, be connected and read power supply or holding wire and read selection transistor between the transistor, with the constant-current source that is connected with holding wire.
Radioscopic image picking up system of the present invention is characterised in that and comprises above-mentioned photoelectric conversion device, X ray generation equipment and control device, and wherein control device control X ray produces the function of equipment and photoelectric conversion device, thereby reads the radioscopic image through object.
According to the present invention, even in large-area transducer, the also loss of the output voltage that can suppress to cause by the increase of parasitic capacitance.So transducer is not subject to The noise, and can provide high sensitivity.In addition, can under the situation that does not adopt the special circuit such as low noise amplifier or constant-current source, constitute read-out device.In addition, can constitute the read-out device of low electrical power consumed and low warming-up effect.In addition, the constant-current source that adopts among the present invention can be made of the thin-film transistor on the glass substrate.So it can form by film forming simultaneously with photo-electric conversion element and other thin-film transistor, thereby is favourable aspect cost.In addition, constant-current source can be set at glass substrate on read-out device at a distance of the position of a segment distance, thereby the influence that alleviates the resistance of holding wire.
In conjunction with the accompanying drawings, according to following explanation, other features and advantages of the present invention will become obviously, and wherein identical Reference numeral is represented same or analogous part.
Description of drawings
Be included in the specification and constitute the accompanying drawing diagram embodiments of the invention of the part of specification, and be used from explanation one and explain principle of the present invention.
Fig. 1 is the photoelectric conversion device, the particularly circuit diagram of the circuit structure of radioscopic image pick device that expression constitutes the first embodiment of the present invention.
Fig. 2 is the timing diagram of the function of the expression radioscopic image pick device that constitutes first embodiment.
Fig. 3 is the photoelectric conversion device, the particularly circuit diagram of the circuit structure of radioscopic image pick device that expression constitutes the second embodiment of the present invention.
Fig. 4 represents the Vds-Ids characteristic curve of the thin-film transistor CT among second embodiment.
Fig. 5 is the photoelectric conversion device, the particularly circuit diagram of the circuit structure of radioscopic image pick device that expression constitutes the third embodiment of the present invention.
Fig. 6 is the photoelectric conversion device, the particularly circuit diagram of the circuit structure of radioscopic image pick device that expression constitutes the fourth embodiment of the present invention.
Fig. 7 is the timing diagram of the function of the expression radioscopic image pick device that constitutes the 4th embodiment.
Fig. 8 is the photoelectric conversion device, the particularly circuit diagram of the circuit structure of radioscopic image pick device that expression constitutes the fifth embodiment of the present invention.
Fig. 9 is the schematic circuit diagram of the existing photoelectric conversion device of expression (radiation image pickup equipment).
Figure 10 is the cross-sectional view of the pixel of the existing photoelectric conversion device of expression (radiation image pickup equipment).
Figure 11 is the circuit diagram of the structure of expression constant-current source.
Figure 12 is the circuit diagram of another structure of expression constant-current source.
Figure 13 is the circuit diagram of the another structure of expression constant-current source.
Figure 14 is the circuit diagram of the another structure of expression constant-current source.
Figure 15 is the figure of the output that produces of the layout (arrange at interval) of expression constant-current source.
Figure 16 is the figure of the output that produces of the layout (in the layout of read-out device one side) of expression constant-current source.
Figure 17 is the figure of expression by the output difference of the layout generation of constant-current source.
Figure 18 is the figure that expression utilizes the radioscopic image picking up system of photoelectric conversion device of the present invention.
Embodiment
Below, will be with reference to the accompanying drawings, illustrate the present invention in more detail according to embodiments of the invention.
(first embodiment)
The first embodiment of the present invention at first is described.Fig. 1 is the photoelectric conversion device, the particularly circuit diagram of the circuit structure of X-ray image pick device that expression constitutes the first embodiment of the present invention.
In the present embodiment, by four pixel PE11, PE12, PE21 and PE22 being arranged in two row, two row, on glass substrate 2, constitute sensor array 1, but the number that constitutes the pixel of sensor array 1 is not limited to such example.Each pixel has the storage capacitance Cs of the signal charge of photo-electric conversion element PD and accumulation photo-electric conversion element PD generation, and photo-electric conversion element PD is made of the PIN photodiode that forms with amorphous silicon.Photo-electric conversion element PD and storage capacitance Cs are grounded at the one end, are interconnected at its other end.Each pixel also has reset mos transistor RT, selects MOS transistor ST and source follower MOS transistor (reading transistor) FT.Reset mos transistor RT, selection MOS transistor ST and source follower MOS transistor FT are made of the thin-film transistor that for example forms with amorphous silicon or polysilicon.Itself have at photo-electric conversion element PD under the situation of enough big electric capacity, storage capacitance Cs can be omitted.
Common reset line R1 usually is connected with the grid of the reset mos transistor RT of pixel PE11 and PE12, and the grid of the common reset mos transistor RT with pixel PE21 and PE22 of common reset line R2 is connected.In addition, each reset mos transistor RT is connected with reset power 5 at the one end, is connected with storage capacitance Cs with photo-electric conversion element PD at the other end.
Public selection wire S1 usually is connected with the grid of the selection MOS transistor ST of pixel PE11 and PE12, and the grid of the common selection MOS transistor ST with pixel PE21 and PE22 of public selection wire S2 is connected.In addition, each selects MOS transistor ST to be connected with source follower power supply (reading power supply) 6 at the one end, and the drain electrode of the source follower MOS transistor FT in the other end and same pixel is connected.
Common signal line Sig1 usually is connected with the source electrode of the source follower MOS transistor FT of pixel PE11 and PE21, and the source electrode of the common source follower MOS transistor FT with pixel PE12 and PE22 of common signal line Sig2 is connected.In addition, the grid of each source follower MOS transistor FT is connected with storage capacitance Cs with photo-electric conversion element PD in the same pixel.
Common reset line R1 and R2, and public selection wire S1 is connected with the scanning circuit 4 with the shift register that is formed by silicon metal with S2.In addition, common signal line Sig1 is connected with the reading circuit 3 that is formed by silicon metal with Sig2.In addition, common signal line Sig1 is connected with the constant-current source I that forms on glass substrate 2 with Sig2.Reading circuit 3 has amplifier Amp1 and the Amp2 that is respectively applied for common signal line Sig1 and Sig2, also has to be used for these output signals are outputed to outside analog multiplexer MUX continuously.On its light receiving surface, sensor array 1 has and the similar luminescent coating of the luminescent coating in existing structure.
Below, the function of the photoelectric conversion device (radioscopic image pick device) of first embodiment is described.Fig. 2 is the timing diagram of function of the photoelectric conversion device (radioscopic image pick device) of expression first embodiment.Among Fig. 2, R1 and R2 represent to put on respectively by reset line R1, R2 the reset pulse of the grid of reset mos transistor RT, and S1 and S2 represent to put on respectively by selection wire S1, S2 the strobe pulse of the grid of selecting MOS transistor ST, and MUX_CLK represents to offer the pulse of analog multiplexer MUX.
Under the state of radioactive ray (X ray) prolonged exposure photoelectric conversion device, when scanning circuit 4 when common reset line R1 applies reset pulse, the current potential of the photo-electric conversion element PD of pixel PE11 and PE12 is reset, and the beginning opto-electronic conversion, thereby in storage capacitance Cs stored charge.In addition, when 4 pairs of common reset lines of scanning circuit R2 applied reset pulse, the current potential of the photo-electric conversion element PD of pixel PE21 and PE22 was reset, and the beginning opto-electronic conversion, thereby in storage capacitance Cs stored charge.
Subsequently, after common reset line R1 is applied reset pulse, when 4 couples of public selection wire S1 of scanning circuit applied strobe pulse, the signal charge of accumulating in the storage capacitance Cs of pixel PE11 and PE12 after the resetting of photo-electric conversion element PD was read out reading circuit 13 by holding wire Sig1.Similarly, after common reset line R2 is applied reset pulse, when 4 couples of public selection wire S2 of scanning circuit applied strobe pulse, the signal charge of accumulating in the storage capacitance Cs of pixel PE21 and PE22 after the resetting of photo-electric conversion element PD was read out reading circuit 13 by holding wire Sig2.
MUX_CLK is synchronous with pulse, and reading circuit 3 is exporting to external processing apparatus etc. by holding wire Sig1 and Sig2 signal supplied.
In the first such embodiment, entire circuit has the source follower circuit structure.So the signal that obtains can be exaggerated and read, and be not subjected to the influence of the parasitic capacitance P on signal Sig1 and the Sig2 in photo-electric conversion element PD.So, can avoid owing to forming the output loss that bigger sensor regions causes.Can also obtain to export the noise of generation among amplifier Amp1, the Amp2 itself that is not subject in reading circuit or the effect of external noise influence.Thereby, can obtain high sensitivity.In addition, because the signal that photo-electric conversion element PD obtains amplifies by source follower, and reading circuit 3 do not need constant-current source, so reading circuit 3 is simple in structure, and the universal component of available cheapness constitutes.Thereby, available particular components essential in the prior art, for example simple structure of the low pass filter of high electrical power consumed or the constant-current source realization reading circuit of not needing.
In the function declaration in front, suppose prolonged exposure radioactive ray (X ray), but radioactive ray also can be intermittently.In the structure of radioscopic image pick device, select MOS transistor can be arranged on source electrode one side of source follower MOS transistor in addition.In addition, constant-current source is not particularly limited aspect circuit structure, can be made of one or more TFT.
(second embodiment)
Below, the second embodiment of the present invention is described.Fig. 3 is the photoelectric conversion device, the particularly circuit diagram of the circuit structure of radioscopic image pick device that constitutes the second embodiment of the present invention.In a second embodiment, the constant-current source I that replacement is adopted in first embodiment provides the thin-film transistor (TFT) that is formed by amorphous silicon CT.The grid of thin-film transistor CT receives the voltage from the power supply 7 that is used for constant-current source.Such structure can be produced by simple manufacture process, because by film forming, constant-current source can form simultaneously with other transistor (reset, selection and source follower).Be respectively applied for reset, the thin-film transistor of selection, source follower and constant-current source can have identical stacked film thickness or the film thickness that has nothing in common with each other.The doping situation that they also can have common doping situation (n type or p type) or have nothing in common with each other.In addition, they can a part be formed by amorphous silicon, and by utilizing for example laser annealing, another part is formed by polysilicon.
Among Fig. 3, constitute the constant-current source that has thin-film transistor CT and be used for the power supply 7 of constant-current source as shown in Figure 11.In this case, the thin-film transistor CT of formation constant-current source can be n type or p type.
At thin-film transistor CT is under the situation of for example n type thin-film transistor, and for source electrode-drain voltage Vds, source electrode-drain current Ids, grid-source voltage Vgs and threshold voltage Vth, thin-film transistor CT shows Vds-Ids characteristic curve as shown in Figure 4.So,, make it to be in and satisfy relation (saturation region of Vds＞Vgs-Vth), thin-film transistor CT can be used as constant-current source by the gate voltage of control TFT CT.
In addition, according to above-mentioned relation, be under the situation of n type thin-film transistor at thin-film transistor, by interconnected gates and source electrode as shown in Figure 12, can enough simple structures realize constant-current source.In addition, according to required electric current, can between grid and source electrode, resistor be set as shown in Figure 13.Structure shown in Figure 12 or 13 allows to omit the power supply that is used for constant-current source.
Another example of having represented the constant-current source that on glass substrate, forms among Figure 14.In this example, under the situation that does not adopt thin-film transistor etc., form pseudo-constant-current source by the resistor of needle drawing on glass substrate.In this case, this resistance is preferably fully greater than the conducting resistance of selecting MOS transistor.
(the 3rd embodiment)
The following describes the third embodiment of the present invention.Fig. 5 is the photoelectric conversion device, the particularly circuit diagram of the circuit structure of radioscopic image pick device that constitutes the third embodiment of the present invention.Second embodiment that is placed between pixel and the reading circuit 3 with the thin-film transistor CT that wherein constitutes constant-current source is opposite, and in the 3rd embodiment, on common signal line, thin-film transistor CT is positioned at and compares with pixel from the farther position of reading circuit 3.In other words, pixel is disposed between thin-film transistor CT and the reading circuit 3.
Below with reference to Figure 15,16 and 17 advantage of arranging constant-current source from reading circuit one segment distance is described.Figure 15 represents wherein to make constant-current source and read-out device structure spaced apart for every signal line, and Figure 16 represents that constant-current source wherein is disposed in the structure of read-out device one side.Be set under the situation of read-out device one side at constant-current source as shown in Figure 16, because resistor assembly R1, R2 and the R3 of holding wire, the actual voltage Vout that reads of read-out device is lower than the source potential Vs of each source follower MOS transistor.For example, just read pixel C, the source potential of read-around ratio FT3 is hanged down the voltage of Δ V=I0 * (R1+R2+R3).
Have at holding wire under the situation of big resistance, for example when constituting large-area photoelectric conversion device, such voltage drop be can not ignore.Figure 17 according to pixels represents the state of voltage drop.On the other hand, arrange that with a certain distance from read-out device constant-current source makes the decline that can avoid the output voltage that the resistance by holding wire causes.For example, equally just read pixel C, electric current flows into resistor assembly R1, R2 and R3 hardly, makes the source voltage of source follower MOS transistor can be read out device and reads, and have voltage drop hardly.Figure 17 shows that also voltage drop exists hardly when constant-current source during with a certain distance from read-out device.Even the situation of can not ignore for the resistance of holding wire resembling in large-area photoelectric conversion device, arranging with a certain distance from read-out device that constant-current source also makes and can avoid defective such as voltage drop as shown in Fig. 5 and 15.
Except the effect that in first and second embodiment, obtains, even can also providing, present embodiment in common signal line, has resistor assembly, the voltage drop in the signal output that will read by reading circuit 3 that also can avoid producing by such resistor assembly.
(the 4th embodiment)
The following describes the fourth embodiment of the present invention.Fig. 6 is the photoelectric conversion device, the particularly circuit diagram of the circuit structure of radioscopic image pick device that expression constitutes the fourth embodiment of the present invention.Opposite with the 3rd embodiment, the 4th embodiment has reading scan thin-film transistor (TFT) RDT in every common signal line Sig1, Sig2.Reading scan thin-film transistor RDT is formed between the pixel and reading circuit 3 on the glass substrate 2.In addition, reading circuit 3 is not provided with analog multiplexer MUX, is transfused among the single amplifier Amp from the output signal of holding wire.Reading circuit 3 also has the reading scan circuit 8 of the grid voltage of scan control reading scan thin-film transistor RDT.
In the 4th embodiment of said structure, in resembling first embodiment after signal charge integration is in storage capacitance Cs, with as shown in Figure 7 at the clock signal clk 1 of holding wire Sig1 with at the clock signal clk 2 of holding wire Sig2 conducting reading scan thin-film transistor RDT synchronously, thereby charges accumulated is read into reading circuit 3 continuously.
In the 4th such embodiment, 3 of reading circuits need amplifier and other necessary logical circuit, then structure further simplified, thereby noise is further reduced, and can obtain higher sensitivity with simpler structure.In the present embodiment, consider sweep speed, preferably laser anneal method is made of polysilicon scanning thin-film transistor RDT by for example utilizing.
(the 5th embodiment)
The following describes the fifth embodiment of the present invention.Fig. 8 is the photoelectric conversion device, the particularly circuit diagram of the circuit structure of radioscopic image pick device that expression constitutes the fifth embodiment of the present invention.The 4th embodiment that links to each other with the drain electrode of wherein selecting MOS transistor ST with source follower MOS transistor FT is opposite, in the 5th embodiment, selects MOS transistor ST to be connected between the source electrode and holding wire Sig1 or Sig2 of source follower MOS transistor FT.The drain electrode of source follower MOS transistor FT directly is connected with source follower power supply 6.
The 5th embodiment like this can provide and the 4th embodiment similar effects.
This equipment is not limited to X ray and detects, and can directly receive visible light on the contrary under the situation that luminescent coating is not provided.In addition, photo-electric conversion element is not limited to PIN photodiode, also can be made of the MIS transducer.Under the situation of utilizing the MIS transducer, also can adopt the reset power that wherein is connected can be by the structure of not shown control device control output voltage with reset transistor.
In addition, photo-electric conversion element can be based on the material that can directly absorb radioactive ray (or X ray) and produce electric charge, such as the so-called directly conversion element of amorphous selenium, GaAs, lead iodide or mercuric iodixde.In this case, by forming on the thin-film transistor glass substrate thereon or connect so direct conversion element forming, can constitute photo-electric conversion element by amorphous silicon or polysilicon.
(the 6th embodiment)
The following describes the sixth embodiment of the present invention, it is the radioscopic image picking up system that utilizes photoelectric conversion device of the present invention.The radioscopic image picking up system of Figure 18 graphic extension sixth embodiment of the present invention.
In X-ray room (image pickup chamber), the X ray 6060 that X-ray tube (X ray generation equipment) 6050 produces sees through patient or those who are investigated's 6061 thoracic cavity 6062, enters imageing sensor 6040.The X ray that enters comprises the information of patient 6061 body interior.The response X ray enters, and scintillator (fluorophor) produces light, and described light is by the photo-electric conversion element opto-electronic conversion of sensor panel, thus the acquisition electrical information.Imageing sensor 6040 is exporting to image processor 6070 as this information of the signal of telecommunication (digital signal).The signal that is used as 6070 pairs of receptions of image processor of image processing apparatus carries out image processing, and outputs it to the display 6080 that constitutes display unit in the control room (operating room).Thereby be presented at image on the display 6080 by observation, the user can obtain the information about patient 6061 body interior.Image processor 6070 also has controlled function, and can motion switch/rest image pattern, perhaps can control X-ray tube 6050.
In addition, image processor 6070 can pass through transmitting device to the signal of telecommunication from imageing sensor 6040 outputs, sends remote location to such as telephone wire 6090, so that in the another location, for example shows on the display unit 6081 in the working doctor chamber.It can also be kept at the signal of telecommunication from imageing sensor 6040 in the tape deck such as CD, and it can be used for diagnosis by the doctor in the another location.The film processor (processor) 6100 that signal also can be configured tape deck is recorded on the film 6110.
Radioscopic image picking up system of the present invention be characterised in that following some:
(1) above-mentioned photoelectric conversion device is arranged in the imageing sensor 6060, and the numeral output after the A/D conversion is carried out appropriate image processing by image processor 6070; With
(2) image processor 6070 has not shown control device, described control device control chart image-position sensor 6040, and X ray produces equipment 6050, display 6080,6081, film processor 6100 etc.
Because under the situation that does not break away from the spirit and scope of the present invention, can make many obviously extensive different embodiment of the present invention, therefore except as limiting in the claim, the present invention is not limited to specific embodiment.
The application requires the priority of Japanese patent application No.2003-389274 that submits on November 19th, 2003 and the Japanese patent application No.2004-180899 that submitted on June 18th, 2004, and these two patent applications are drawn at this and are reference.
Claims (16)
1, a kind of photoelectric conversion device comprises:
Photo-electric conversion element;
Reset transistor, its source electrode is connected with described photo-electric conversion element, and drain electrode is connected with reset power;
Read transistor, its grid is connected with described photo-electric conversion element, drains and reads power supply and be connected;
Read the holding wire that transistorized source electrode is connected with described;
Be connected described power supply or described holding wire and the described selection transistor of reading between the transistor read; With
The constant-current source that is connected with described holding wire.
2, according to the described photoelectric conversion device of claim 1, wherein said photo-electric conversion element, described transistor, described holding wire and the described constant-current source read are formed on the single insulated substrate.
3, according to the described photoelectric conversion device of claim 1, also comprise:
The read-out device that is connected with described holding wire;
Wherein on described holding wire, described constant-current source is set at and compares to reading transistor, to the farther position of distance of described read-out device.
4, according to the described photoelectric conversion device of claim 3, wherein said read-out device comprises the analog multiplexer that is connected with described holding wire.
5, according to the described photoelectric conversion device of claim 4, wherein said analog multiplexer is forming by the thin-film transistor that is made of amorphous silicon or polysilicon with described reading on the identical insulated substrate of transistor.
6, according to the described photoelectric conversion device of claim 1, wherein said constant-current source comprises the constant source flowing transistor that its grid is connected with the power supply that is used for constant-current source.
7, according to the described photoelectric conversion device of claim 6, the wherein said power supply that is used for constant-current source provides the satisfied voltage that concerns Vds＞Vgs-Vth to the grid of described constant source flowing transistor, wherein Vds is a drain electrode-source voltage, and Vgs is a grid-source voltage, and Vth is a threshold voltage.
8, according to the described photoelectric conversion device of claim 1, wherein said constant-current source comprises wherein grid and the interconnective constant source flowing transistor of source electrode.
9, according to the described photoelectric conversion device of claim 1, wherein said constant-current source comprises the constant source flowing transistor that wherein strides across resistor connection grid and source electrode.
10, according to the described photoelectric conversion device of claim 1, wherein utilize amorphous silicon layer or polysilicon layer, form described reset transistor, described at least one of reading in transistor, described selection transistor and the described constant-current source.
11, according to the described photoelectric conversion device of claim 1, also comprise luminescent coating, described luminescent coating absorbs radioactive ray, and sends the light of the wavelength zone that can be detected by described photo-electric conversion element.
12, according to the described photoelectric conversion device of claim 1, wherein said photo-electric conversion element is made of PIN photodiode or MIS transducer.
13, according to the described photoelectric conversion device of claim 1, wherein said photo-electric conversion element is the direct sunshine electric transition element that directly radioactive ray is converted to electric charge.
14, according to the described photoelectric conversion device of claim 13, wherein said direct sunshine electric transition element is made of the material that is selected from the group that amorphous selenium, GaAs, gallium phosphide, lead iodide, mercuric iodixde, CdTe and CdZnTe constitute.
15, a kind of photoelectric conversion device comprises:
The two-dimensional array of a plurality of pixels, each pixel comprises:
Photo-electric conversion element;
Reset transistor, its source electrode is connected with described photo-electric conversion element, and drain electrode is connected with reset power;
Read transistor, its grid is connected with described photo-electric conversion element, drains and reads power supply and be connected;
Be connected described power supply or holding wire and the described selection transistor of reading between the transistor read;
Many common signal lines that are connected with described a plurality of pixels; With
The constant-current source that is connected with described common signal line.
16, a kind of radioscopic image picking up system comprises according to claim 1 or 15 described photoelectric conversion devices, and X ray produces equipment and control device;
Wherein said control device control X ray produces the function of equipment and photoelectric conversion device, thereby reads the radioscopic image through object.
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| JP389274/2003 | 2003-11-19 | ||
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Cited By (5)
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| CN101547318B (en) * | 2008-03-26 | 2011-07-27 | 株式会社东芝 | Image sensor and driving method therefor |
| US8766338B2 (en) | 2010-03-12 | 2014-07-01 | Semiconductor Energy Laboratory Co., Ltd. | Semiconductor device including photosensor and transistor having oxide semiconductor |
| CN104167998A (en) * | 2013-05-17 | 2014-11-26 | Nlt科技股份有限公司 | Amplifier circuit and image sensor using amplifier |
| CN105935296A (en) * | 2016-04-13 | 2016-09-14 | 成都京东方光电科技有限公司 | Pixel circuit, digital X-ray detection device, and detection method thereof |
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| JP3522953B2 (en) * | 1996-03-14 | 2004-04-26 | 株式会社東芝 | Solid-state imaging device |
| JPH10108075A (en) * | 1996-09-27 | 1998-04-24 | Toshiba Corp | Signal amplification type image-pickup device |
| JP3788561B2 (en) * | 1999-05-13 | 2006-06-21 | シャープ株式会社 | Solid-state imaging device |
| JP3667187B2 (en) * | 2000-03-02 | 2005-07-06 | キヤノン株式会社 | Solid-state imaging device |
| JP4441042B2 (en) * | 2000-03-09 | 2010-03-31 | キヤノン株式会社 | Solid-state imaging device |
| JP2001298663A (en) * | 2000-04-12 | 2001-10-26 | Semiconductor Energy Lab Co Ltd | Semiconductor device and its drive method |
| JP2002148342A (en) * | 2000-11-07 | 2002-05-22 | Canon Inc | Radiation imaging device |
| US6855937B2 (en) * | 2001-05-18 | 2005-02-15 | Canon Kabushiki Kaisha | Image pickup apparatus |
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| CN101547318B (en) * | 2008-03-26 | 2011-07-27 | 株式会社东芝 | Image sensor and driving method therefor |
| US8766338B2 (en) | 2010-03-12 | 2014-07-01 | Semiconductor Energy Laboratory Co., Ltd. | Semiconductor device including photosensor and transistor having oxide semiconductor |
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| CN104167998A (en) * | 2013-05-17 | 2014-11-26 | Nlt科技股份有限公司 | Amplifier circuit and image sensor using amplifier |
| CN104167998B (en) * | 2013-05-17 | 2019-01-18 | Nlt科技股份有限公司 | Amplifier circuit and the imaging sensor for using amplifier circuit |
| CN105935296A (en) * | 2016-04-13 | 2016-09-14 | 成都京东方光电科技有限公司 | Pixel circuit, digital X-ray detection device, and detection method thereof |
| CN105935296B (en) * | 2016-04-13 | 2019-03-08 | 成都京东方光电科技有限公司 | A kind of pixel circuit, digital X-ray detection device and its detection method |
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| CN100452842C (en) | 2009-01-14 |
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