JP2001103378A - Photoelectric converter, radiation ray image pickup device and method for driving the photoelectric converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoelectric converter with high sensitivity, high reliability and a small delay at the time of picking up an image and to provide its drive method and a radiation ray image pickup device. SOLUTION: In the photoelectric converter that has a plurality of photoelectric conversion elements, a drive circuit 608 to drive a plurality of the photoelectric conversion elements, and a control circuit 609 that controls the drive circuit 608, the control circuit 609 has a 1st mode where a state suitable for photographing an image is obtained and a 2nd mode where the image is photographed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric conversion device, a radiation imaging device, and a method of driving a photoelectric conversion device. More particularly, the present invention relates to a time lag from when a photographing switch is pressed to when the photoelectric conversion device performs a photographing operation. The present invention is suitably used for a photoelectric conversion device, a radiation imaging device, and a method for driving the photoelectric conversion device, which can eliminate a delay and can capture an image at a timing intended by an operator.

[0002]

2. Description of the Related Art With the recent rapid spread of personal computers (hereinafter referred to as PCs), digitization of information and networking of information transmission have progressed, and photographs which have conventionally been stored and distributed on media such as paper have been developed. Documents tend to be stored and distributed as digital information. This is due to the fact that image and audio information can be easily digitized with the advancement of technology, and computer networks (hereinafter referred to as networks) as infrastructure for transmitting such information. This is due to the rapid expansion of the Internet in recent years.

A great advantage of digitization and networking of information is that information can be transmitted regardless of distance and time. That is, if there is a PC or terminal connected to the network, it becomes possible to obtain necessary information on the spot when desired. Further, there are merits that information processing (image processing and retrieval) is facilitated and that the space required for storage is small.

[0004] This digitization is also progressing in the medical field. For example, if a network is connected within a hospital or between hospitals, an X-ray image of a certain patient can be transferred to a plurality of doctors for diagnosis, or a doctor at a university hospital can be diagnosed at a clinic in a town. In addition, images can be obtained immediately without time-consuming and time-consuming processes such as development, and storage of information as an electronic file on a magnetic disk facilitates management, retrieval, and statistics of vast patient data. This leads to a major improvement in the medical environment, such as the need for less medical care.

[0005] However, the digitization of medical equipment by digitization and networking in the medical field is not limited to radiographic devices, that is, X-rays, except for recent computer-controlled technologies and the latest diagnostic devices that are enabled by digital technologies. Until recently, a digital X-ray imaging apparatus that reduces the image quality of conventional silver halide photography has not been realized.

Normally, in an X-ray photograph, an X-ray is irradiated to an affected part, the X-ray transmitted through the affected part is converted into light by a fluorescent plate, and the silver halide film is exposed. The reason why such a digital X-ray imaging apparatus that reduces the image quality of a silver halide photograph could not be realized is that a sensor having the same size and the same resolution as the film used for the silver halide film could not be realized. .

Recently, when a semiconductor is irradiated with light in a state where a voltage is applied, a photoelectric conversion element utilizing the flow of an amount of current proportional to the amount of light, and an output control of a current generated by incident light. With the development of a two-dimensional optical sensor in which thin film transistors (hereinafter, referred to as TFTs) to be formed are formed in a matrix form using hydrogenated amorphous silicon (hereinafter, referred to as a-Si) together with electrodes and wirings, the resolution, sensitivity, and sensitivity of silver halide films have been improved. Equally, more sensors have been realized, and a digital X-ray imaging apparatus has become possible. Usually digital X
As shown in FIG. 8, the X-ray imaging apparatus is a patient 1 to be irradiated.
An X-ray source 102 for irradiating X-rays 01, a fluorescent substance 103 for converting X-rays transmitted through the patient 101 into light, and a photoelectric conversion element for converting light from the fluorescent substance 103 into an electric signal are two-dimensionally arranged. The signal processing of the image information from the conversion means 104 and the photoelectric conversion means 104, the control signal to the photoelectric conversion means 104, the control signal to the X-ray source 102, and the image information to the display 106
The control circuit 107 includes a photographing switch 105 for performing on / off control of the operation of the control / drive circuit 107. In addition,
The photoelectric conversion unit 104 and the drive / control circuit 107 constitute a photoelectric conversion device.

However, in a photoelectric conversion device in which photoelectric conversion elements are two-dimensionally arranged, a problem called a dark current is a current generated independently of light in the photoelectric conversion element. And the light sensitivity of the photoelectric conversion element is reduced, which directly affects the image quality. Therefore, for practical reasons, such as preventing diagnosis errors, it is desirable that the digital X-ray imaging apparatus be a sensor drive or apparatus with a small dark current. When a voltage is applied to the photoelectric conversion element or immediately after the voltage applied to the photoelectric conversion element changes, a large amount of dark current flows. Needs to be performed when the dark current has decreased after the elapse of time.

[0009]

In actual radiography, when a digital X-ray imaging device using the above-mentioned photoelectric conversion device is used, a voltage is always applied to the photoelectric conversion element and the TFT. This is effective in suppressing image degradation due to dark current. However, application of a voltage for a long time causes deterioration of the photoelectric conversion element and the TFT, and is not appropriate in terms of reliability and practical use. On the other hand, if a voltage is applied to the photoelectric conversion device immediately before imaging, for example, at the stage when the patient is at the imaging position, the patient will have to wait until the dark current becomes smaller and imaging becomes possible. When taking a chest image, the patient must hold their breath to prevent the organ from moving due to breathing and blurring the image, and having the patient hold their breath until they can be imaged places stress on the patient Will be.

From the above, the driving method of the two-dimensional photoelectric conversion device in the digital X-ray imaging apparatus is as shown in FIG. The photoelectric conversion device performs a refresh operation of discharging the charge stored in the photoelectric conversion element until the dark current decreases after the voltage is applied, and a T in the photoelectric conversion device for discharging the charge stored in the photoelectric conversion device by the dark current.
The TFT is turned on in order to prevent the reliability of the TFT from deteriorating due to the initialization operation for turning on / off the FT and the switching operation.
The three operations of Wait operation in a state where the FF is kept are repeatedly performed. This operation prevents the reliability of the device from being unnecessarily reduced.

Immediately after the end of the refresh operation, the electric charge trapped in the deep trap inside the photoelectric conversion element gradually leaks out and becomes a dark current, so that an initialization operation is always required after the refresh operation. Until the amount of dark current suitable for imaging is reached (after the set appropriate time has elapsed), the operator is informed that the image can be captured by a display device such as a lamp, and the operator presses the X-ray imaging switch. Then, shooting is performed. The imaging operation is performed by irradiating the X-rays and reading out the electric charges accumulated in the photoelectric conversion element as needed. Here, since the amount of charge stored in the photoelectric conversion element differs depending on the driving of the photoelectric conversion device until the photographing switch is pressed, the same sensitivity and image quality cannot always be realized.
In order to prevent this, when the photographing switch is pressed, it is necessary to perform the photographing after performing the refresh operation and the initialization operation. For this reason, a large photographing delay occurs.

If the delay (delay) from the pressing of the imaging switch to the photographing is large, the time required for the photographing becomes long, and it is difficult to know when the photographing is actually performed. Since it is not possible to take the image intended by the user, it is necessary to perform re-photographing, and the usability is poor. In particular, since re-imaging and a long imaging time place a burden on the patient, it is desired that such poor usability be improved.

[0013] In order to solve this problem, the photoelectric conversion device must be driven before photographing before the photographing switch is pressed. For example, as shown in FIG. 10, when a voltage is applied to the photoelectric conversion device, the drive is always repeated for the initialization operation, and the refresh operation is periodically performed, so that the delay at the time of photographing is less than one time. The time required for the conversion operation is sufficient. Initialization operation is about 0.2
The photographing delay is smaller than about 0.3 second to 0.3 second. However, in that case, the TFT is repeatedly turned ON / OFF until the photographing is completed. Suppose that all the TFTs of the photoelectric conversion device are turned on once for each initialization operation.
When N / OFF is set, when TFT is driven for one second and when it is not, three to five times as many TFTs are used.
Will be driven. In this case, when it takes time to prepare for imaging, for example, when there is a risk of moving the photoelectric conversion device for a long time, for example, when the patient cannot immediately move to the imaging position, improvement is desired in consideration of reliability.
Further, when the photographing switch is pressed immediately after the refresh operation, a photographing delay occurs because the initialization operation needs to be performed. As described above, the fact that the shooting delay is different each time shooting is performed also deteriorates usability. In addition, refresh operation after the shooting switch is pressed,
If the time required for the initialization operation is shortened, noise due to dark current increases and image quality deteriorates.

Therefore, it is desired to realize a method of driving a photoelectric conversion device which does not cause deterioration in image quality and reliability and has no photographing delay.

(Object of the Present Invention) An object of the present invention is to provide a photoelectric conversion device having high sensitivity, high reliability, and a small delay at the time of photographing, a driving method thereof, and a radiation imaging device. is there.

[0016]

A photoelectric conversion device according to the present invention comprises a plurality of photoelectric conversion elements, a drive circuit for driving the plurality of photoelectric conversion elements, and a control circuit for controlling the drive circuits. Wherein the control circuit comprises: a first mode for setting a state suitable for capturing an image;
And a second mode for taking an image.

The method of driving a photoelectric conversion device according to the present invention is a method of driving a photoelectric conversion device in which a plurality of photoelectric conversion elements are two-dimensionally arranged. , A second mode in which an image is taken upon completion of the first mode.

According to the present invention, by providing a first mode for making a state suitable for photographing an image and a second mode for photographing an image, a photographing delay caused by driving a photoelectric conversion element during photographing can be reduced or reduced. The drive can be eliminated. The transition to the first mode and the second mode can be arbitrarily switched by a switch operated by an operator or the like.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) A method and an apparatus for driving a photoelectric conversion device according to the present invention will be described below.

FIG. 1 is a flowchart showing a driving method according to a first embodiment of the present invention, FIG. 2 is a timing chart thereof, and FIG. 3 is a configuration diagram of an X-ray imaging apparatus according to the first embodiment of the present invention. .

In the present embodiment, as shown in FIG. 1, the operator sets the photoelectric conversion device in a state suitable for photographing (photographing preparation mode) before photographing so that photographing can be performed immediately after the photographing switch is pressed. Was changed at any timing. The driving method will be described below with reference to FIGS.

First, from the state where no voltage is applied to the TFT and the photoelectric conversion element of the photoelectric conversion device (Power OFF),
A state in which a voltage is applied (Power ON) is set, and a Ready mode is set. Ready mode refers to ON / OFF of TFT.
This is an operation in which the above-described refresh operation, initialization operation, and wait operation are sequentially performed in order to reduce the reliability of the photoelectric conversion device. Further, in the Ready mode, it is possible to prevent the transition to the photographing preparation mode until the dark current generated in the photoelectric conversion element immediately after the application of the voltage is reduced. Notify the operator of the impossibility. This Re
At the time of the ady mode, the operator performs an imaging preparation such as inputting imaging conditions and moving a patient in front of the imaging apparatus.

Next, when the switch SW1 is pressed by the operator, the photoelectric conversion device shifts to the photographing preparation mode. The photographing preparation mode is a drive for performing an initializing operation after a refresh operation is performed until SW2 serving as a photographing switch is pressed. By repeating the initialization operation, the output which does not depend on the light such as the dark current is initialized, and the image can be immediately taken when the switch SW2 is pressed. Further, even if the switch SW2 is pressed during the initialization operation, the mode can be shifted to the photographing mode after the initialization operation is completed. The time required for the initialization operation depends on the specifications of the photoelectric conversion device, but is as short as 0.1 to 0.3 seconds and can be ignored.

When the switch SW2 is pressed in the photographing preparation mode, the photographing mode is set. In the shooting mode, the photoelectric conversion device has two operations, a photoelectric conversion operation and a reading operation. In the photoelectric conversion operation, the TFT is turned off, a voltage is applied to the photoelectric conversion element, and the photoelectric conversion element converts the light into light by the phosphor using the photoelectric conversion element. The reading operation is an operation of turning on the TFT as needed, taking out the electric charge accumulated in the photoelectric conversion element as a current, and obtaining an image.
X-ray irradiation is performed during this photoelectric conversion operation.

After the X-ray exposure radiography, a refresh operation is performed to discharge the electric charge accumulated in the photoelectric conversion element by the radiographing operation, and further, an initialization operation is performed, and then reading for obtaining correction data, that is, FPN ( Fixed pattern noise) shooting. This operation is performed in a state where X-rays are not irradiated, and an output which is not caused by light such as fixed pattern noise is corrected by using this data. There is no particular limitation on the number of initialization operations before FPN imaging, but an optimum number is performed in consideration of image quality and time until image output.

After the above operation is completed, if the photoelectric conversion device is to continuously shoot, the ready drive is performed and the process waits for the next shooting. Otherwise, the voltage applied to the photoelectric conversion element and the TFT is set to zero (Power OF
F).

According to the above driving method, it is possible to drive the photoelectric conversion device without photographing delay without lowering the reliability of the photoelectric conversion device.

Further, when the device is driven for a long time in the photographing preparation mode, electric charges are accumulated in the photoelectric conversion device due to dark current, and the photoelectric conversion device cannot output a current corresponding to the irradiated light at the stage of photographing. Sometimes
Further, long-time driving poses a problem in reliability. Therefore, it is also possible to perform a refresh operation after a certain period of time (restart of the shooting mode) or an operation of shifting to the Ready mode.

The shift to each mode by pressing the switch SW is performed after the operation which is directly performed when the operation being performed at the time of the shift is interrupted is interrupted.

FIG. 3 is a block diagram of an X-ray imaging apparatus using the above driving method. As shown in FIG. 3, the X-rays emitted from the X-ray source 602 pass through the human body and reach the phosphor 603, and a part thereof is absorbed or attenuated by the human body (patient) 601 and a signal having information on the human body is obtained. Become. This X-ray is converted into light by a phosphor 603 as a wavelength converter, and is converted into light.
04 is converted into an electric signal. The wavelength converter means radiation such as X-rays, α-rays, β-rays, γ-rays, visible light,
An electromagnetic wave having a wavelength that can be converted into an electric signal by a sensor, such as infrared light or ultraviolet light, is converted into an electromagnetic wave, for example, visible light. The information of the human body that has become the electric signal is sent to the image processing circuit 607 and converted into a digital image. The photoelectric conversion element is driven by a signal output from the driver circuit 608 and a supplied voltage. The control circuit 609 includes the driving circuit 608, the image processing circuit 607, and the X-ray source 60 described above.
2, an input device 613, a display 611 and a lamp 612 for displaying an image, a driving status of the device, and a captured image, a recording device 610 such as a magnetic disk, and the above-described switches 605 (SW1) and 606 (SW2). It is connected. The photoelectric conversion device includes a photoelectric conversion unit 604, a driving circuit 608, and a control circuit 609. Here, the switches SW1 and SW2 are mechanical switches which are turned on when a button is pressed mechanically. If the switches SW1 and SW2 are pressed by mistake without pressing SW1, the operation is canceled. In addition, a mechanical mechanism is built in such that SW2 cannot be pressed unless SW1 is pressed. Such a switch is disclosed in, for example, JP-A-9-294229. Note that such a mechanical mechanism may be configured by an electronic circuit. The operator operates the input device 61
The signals of SW1 and SW2 for issuing various shooting conditions and driving mode switching and shooting commands set through the control circuit 3 are sent to the control circuit 609, and the control circuit 609 uses the photoelectric conversion means 604 and The X-ray source 602 is driven.

When the control circuit 609 receives a signal indicating that the switch SW1 has been pressed and turned on, the control circuit 609 causes the drive circuit 608 to change the drive mode to the photographing preparation mode. In addition, the signal of the switch SW1 not only causes the photoelectric conversion unit 604 to shift to the shooting preparation mode, but also activates an apparatus that can operate immediately after the power is turned on. When the switch SW2 is pressed and turned on, the X-ray is irradiated with the specified dose and time, and the photoelectric conversion element receives a control signal of the drive circuit 608 to enter the imaging mode. At this time, even if the switch SW2 is kept depressed, X-rays are emitted for the time specified by the control circuit 609, and the photoelectric conversion unit 604 performs an image reading operation and subsequent operations. If the time from when the switch SW1 is pressed to when the switch SW2 is pressed becomes extremely long, as described above, a problem occurs in terms of image quality and device reliability. Then, it shifts to Ready mode.

Here, the photoelectric conversion means 6 in this embodiment
04 will be described. FIG. 4 is a configuration diagram showing a photoelectric conversion unit having 4 × 4 pixels. As shown in FIG. 4, the photoelectric conversion unit includes one photoelectric conversion element 703 and one TFT.
The pixels obtained by combining 702 are arranged in a two-dimensional array, and a gate line 704 for applying a voltage to the gate electrode of the TFT, a sensor bias line 706 for applying a voltage to the photoelectric conversion element 703, and a pixel are output via the TFT 702. A signal line 705 for transferring an electrical signal is arranged. In the figure, S11 to S44 indicate arranged photoelectric conversion elements, and T11 to T44 indicate arranged TFTs.

The photoelectric conversion element 703 is composed of a photoelectric conversion section for converting light into an electric signal by a photoelectric effect and a capacitor section for accumulating generated charges. In the structure of the photoelectric conversion element described in this embodiment, a photoelectric conversion portion and a capacitor portion can be formed simultaneously.

Hereinafter, a method for forming a TFT and a photoelectric conversion element will be described with reference to FIG. 5 showing a layer configuration for one pixel.

A chromium thin film of about 500 angstroms is deposited on an insulating substrate such as glass or a substrate 807 having at least an electrically insulating surface by a sputtering method or a resistance heating method, and is patterned by photolithography to remove unnecessary portions. Is removed by etching. This chromium thin film becomes the gate electrode layer 805 and the lower electrode layer 808 of the photoelectric conversion element. Next, an a-SiNx film of about 2000 angstroms which becomes the insulating layers 804 and 806 in the same vacuum by the CVD method, an a-Si film of about 6000 angstroms which becomes the photoelectric conversion layer 811 of the photoelectric conversion element and the channel layer 801 of the TFT. The hole injection blocking layer 810 of the photoelectric conversion element and the ohmic contact layer 803 of the TFT.
About 500 angstroms of n ⁺ a-Si
The layers are sequentially deposited. After etching a portion to be a contact hole by reactive ion etching (RIE) or the like, aluminum is deposited by about 10000 angstroms by sputtering or resistance heating. Patterning is performed by photolithography, unnecessary portions are removed by etching, and a sensor bias electrode 815 for applying a voltage to the photoelectric conversion element and a signal line 814 are formed. Furthermore, RI is patterned by photolithography.
Excess portions are etched by E to form a source electrode 802 and a drain electrode 812 of the TFT. Further, the TFT and the photoelectric conversion element are separated by removing unnecessary a-Si, a-SiNx, and n ⁺ a-Si by etching. Although only one pixel is shown in FIG. 5, it goes without saying that a plurality of pixels are formed simultaneously. Finally, a protective film 81 is formed by depositing a-SiNx or the like to improve moisture resistance.
Form 3 This method for producing a photoelectric conversion element has a feature that the main parts of the photoelectric conversion element and the TFT can be simultaneously formed.

As the TFT and the IC for driving the photoelectric conversion element, an IC manufactured using a single crystal semiconductor is used. A shift register 711 (SR) for applying a voltage to the gate electrode of the TFT of each pixel shown in FIG. 4 switches a voltage applied to the gate electrode by a control signal, and turns ON / OFF the TFT.
Govern The sensor power supply 701 connected to the sensor bias line 706 has two power supplies Vs and Vref for the photoelectric conversion mode and the refresh mode. Signal line 705
Are connected to a signal line reset switch 707 and an amplifier 708, respectively, and amplify an electric signal sent from the TFT. A sample hold circuit 709 is connected to the output stage of the amplifier 708, and holds the output of the amplifier until the multiplexer 710 reads out.

In the image reading operation of the photoelectric conversion means, the potential of one gate line is set to Hi, and the TFT of one horizontal line is first set.
(T11 to T14) are turned ON. In this state, the output of the sample-and-hold circuit 709 is sequentially read out by the multiplexer 710 to obtain one horizontal line of image information. After reading the information of all the pixels in one horizontal row, the signal line 705 is reset to the GND potential, the gate line voltage is set to Low, and the TFT is set to O.
Set to FF. The image information obtained by the photoelectric conversion means can be obtained as an electric signal by sequentially performing the above operation for all the lines. As described above, 4 × 4 pixels have been described.
The number of pixels does not depend on this.

Next, the refresh operation in the present embodiment,
The initialization operation will be described.

The refresh operation will be described with reference to the band diagram of FIG. FIG. 6 (a)
Indicates a photoelectric conversion mode. At this time, a photocurrent is generated by electrons and holes generated by photoelectric conversion in the photoelectric conversion layer drifting due to an electric field, holes drifting to the interface between the insulating layer and the photoelectric conversion layer, and electrons drifting to the hole injection blocking layer. However, if light continues to flow, holes accumulate at the interface between the insulating layer and the photoelectric conversion layer, the electric field of the photoelectric conversion layer decreases, the probability of recombination of generated electrons and holes increases, and a current proportional to light stops flowing. As shown in FIG. 6B, in the refresh operation, holes accumulated at the interface between the insulating layer and the photoelectric conversion layer are discharged by making the voltage applied to the photoelectric conversion element smaller than the voltage applied in the photoelectric conversion mode. . Again, a current proportional to the light output can be obtained.

The initialization operation is mainly for resetting the signal line 705 and the lower electrode of the photoelectric conversion element. Specifically, the signal line 705 is reset by a reset switch 707 while the TFT 702 is turned on.
By performing this for all the signal lines 705, the initialization of all the pixels is completed. The TFT is turned on by a method of sequentially turning on one horizontal line as in a read operation. In this case, assuming that the ON time of one horizontal line of TFTs is 100 μsec, it takes 0.2 seconds for a photoelectric conversion device of 2000 × 2000 pixels. The initialization operation may be a method in which a plurality of lines or all the TFTs are turned on and the time required for the initialization operation is shortened. If the switch is pressed during the initialization operation,
It is desirable from the viewpoint of image quality to shift to the next operation when the initialization of all pixels is completed. This is because a portion where the initialization operation is not performed may become uneven and appear in an image.

Although the first embodiment has been described above, the photoelectric conversion element and device used in this embodiment may have a structure other than that described above. The refresh operation may be any operation other than the above-described method as long as it is an operation of discharging the charge accumulated in the photoelectric conversion element.

(Second Embodiment) A second embodiment of the present invention will be described. In the first embodiment, when it is known in advance that shooting is to be performed immediately after a voltage is applied to the photoelectric conversion element, the Ready drive can be omitted. FIG. 7 shows a flowchart of the second embodiment of the present invention. In this case, the photoelectric conversion device is the switch SW1
A voltage is applied in response to the signal (1), and the mode immediately changes to the shooting preparation mode.

This operation method is suitable for a case where an image is to be taken after being placed at an image taking place, such as a portable photoelectric conversion device. Further, in the case where a photoelectric conversion element having a very small dark current immediately after voltage application is developed in the future, the driving method of the present embodiment is used to eliminate photographing delay and reduce the operation time of the photoelectric conversion device. Therefore, a highly reliable photoelectric conversion device can be provided.

[0045]

As described above, according to the present invention, it is possible to provide an image pickup apparatus which can take an image at the same time as the photographing switch is pressed, and can easily take an image intended by the operator. In addition, since the number of times of driving the photoelectric conversion element and the TFT is suppressed, an imaging device that is compatible with ease of use and high reliability can be provided.

Further, when the photoelectric conversion device of the present invention is used for an X-ray imaging device, a patient-friendly X-ray imaging device with less imaging failures and shorter imaging time can be provided.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a method for driving a photoelectric conversion device according to a first embodiment of the present invention.

FIG. 2 is a timing chart illustrating an operation of the photoelectric conversion device according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram of an X-ray imaging apparatus using a photoelectric conversion device according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram of a photoelectric conversion device according to the first embodiment of the present invention.

FIG. 5 is a layer configuration diagram of a photoelectric conversion element in a first embodiment according to the present invention.

FIG. 6 is a band diagram of a photoelectric conversion element and a refresh mode of the photoelectric conversion element according to the first embodiment of the present invention.

FIG. 7 is a flowchart illustrating a method for driving a photoelectric conversion device according to a second embodiment of the present invention.

FIG. 8 is a configuration diagram of an X-ray imaging device using a photoelectric conversion device.

FIG. 9 is a timing chart showing the operation of the X-ray imaging apparatus of FIG.

FIG. 10 is a timing chart showing a drive pattern of an X-ray imaging apparatus with an improved imaging delay.

[Explanation of symbols]

 601 Human body (patient) 602 X-ray source 603 Phosphor 604 Photoelectric conversion means 605 Switch (SW1) 606 Switch (SW2) 607 Image processing circuit 608 Drive circuit 609 Control circuit 610 Recording device 611 Display 612 Lamp 613 Input device

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 31/09 H04N 5/32 H04N 5/32 H01L 31/00 A (72) Inventor Noriyuki Kaibe Ota, Tokyo 3-30-2 Shimomaruko-ku, Canon Inc. (72) Inventor Toshikazu Tamura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F-term (reference) 2G088 EE03 FF02 GG20 KK05 LL11 5C024 AA01 AA12 CA10 CA20 GA31 5F088 AA11 AB05 BA20 BB03 CA02 EA08 KA03 LA08

Claims (19)

[Claims] 1. A photoelectric conversion device comprising: a plurality of photoelectric conversion elements; a driving circuit for driving the plurality of photoelectric conversion elements; and a control circuit for controlling the driving circuit. A photoelectric conversion device comprising: a first mode for setting a state suitable for capturing an image; and a second mode for capturing an image. 2. The photoelectric conversion device according to claim 1, wherein the first mode is a shooting preparation mode including a refresh operation and an initialization operation, and the second mode is a shooting mode. . 3. The photoelectric conversion device according to claim 1, wherein a first mode for selecting the first mode is set.
And a second switch for selecting the second mode.
And a photoelectric conversion device. 4. The photoelectric conversion device according to claim 3, wherein the control circuit is configured to turn on / off the first switch.
F and ON / OFF of the second switch,
A photoelectric conversion device for selecting the first mode or the second mode. 5. The photoelectric conversion device according to claim 1, wherein the control circuit terminates the first mode or lapses the first mode after a lapse of a predetermined time in the first mode. Photoelectric conversion device that restarts. 6. The photoelectric conversion device according to claim 1, wherein the photoelectric conversion device performs driving irrespective of output of image information in the first mode. 7. The photoelectric conversion device according to claim 1, wherein the first mode and the second mode are selected by a mechanical switch. 8. The photoelectric conversion device according to claim 1, wherein the photoelectric conversion element has a first electrode, an insulating layer, a photoelectric conversion layer, a high-concentration impurity semiconductor layer, and a second electrode. 9. The photoelectric conversion device according to claim 1, further comprising a switch element corresponding to each of the photoelectric conversion elements. 10. The photoelectric conversion device according to claim 9, wherein the switching element is a transistor having a first electrode, an insulating layer, a semiconductor layer, an ohmic contact layer, and second and third electrodes. apparatus. 11. The photoelectric conversion device according to claim 8, wherein the photoelectric conversion layer is a hydrogenated amorphous silicon layer,
The photoelectric conversion device, wherein the insulating layer includes a nitrogenated amorphous silicon layer. 12. The photoelectric conversion device according to claim 10, wherein said photoelectric conversion element has the same layer configuration as that of said switch element. 13. The photoelectric conversion device according to claim 1, wherein the control circuit performs an operation of discharging charges accumulated in the photoelectric conversion element in the first mode. 14. The photoelectric conversion device according to claim 1, further comprising a wavelength converter on an image information incident side of the photoelectric conversion element. 15. The photoelectric conversion device according to claim 14, wherein the wavelength converter is a phosphor. 16. A radiation imaging apparatus comprising: a radiation source for irradiating a radiation to an irradiation target; and the photoelectric conversion device according to claim 14 or 15, wherein the radiation enters through the irradiation target. 17. The radiation imaging apparatus according to claim 16, wherein the radiation source is controlled by a control circuit of the photoelectric conversion device. 18. A method for driving a photoelectric conversion device in which a plurality of photoelectric conversion elements are arranged two-dimensionally, wherein a first mode for setting a state suitable for photographing an image and an image with the end of the first mode are provided. And a second mode for capturing an image. 19. The method for driving a photoelectric conversion device according to claim 18, wherein the first mode is a shooting preparation mode, and the second mode is a shooting mode.