CN112002721A - Thin film transistor array substrate, pixel circuit, X-ray detector and driving method thereof - Google Patents
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- H01L27/144—Devices controlled by radiation
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
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- H01L27/144—Devices controlled by radiation
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- H01L27/14601—Structural or functional details thereof
- H01L27/14609—Pixel-elements with integrated switching, control, storage or amplification elements
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Abstract
The invention provides a thin film transistor array substrate, a pixel circuit, an X-ray detector and a driving method thereof, which relate to the technical field of photoelectricity, wherein the thin film transistor array substrate comprises a scanning line and a reading scanning line which are horizontally arranged, a data line and a bias line which are vertically arranged, and a plurality of pixel units which are defined by the crossing of the scanning line and the data line, each pixel unit comprises a photoconductive thin film transistor positioned in a photoconductive area and a reading thin film transistor positioned at a reading end; and simultaneously, the pixel structure and the process structure are simplified.
Description
Technical Field
The invention belongs to the technical field of photoelectricity, and particularly relates to a thin film transistor array substrate, a pixel circuit, an X-ray detector and a driving method of the X-ray detector.
Background
In recent years, radiographic imaging devices for flat panel detectors made of semiconductor materials for capturing X-rays have been increasingly used in the fields of medical equipment, industrial nondestructive testing, public safety, and the like.
Flat panel X-ray image detectors are generally classified into two thin film transistor array technologies. The first is an indirect detection type image detector. For example, a large-area flat panel X-ray image sensor can be fabricated by depositing a photoelectric conversion film (e.g., hydrogenated amorphous silicon diode film) on the TFT pixel array fabricated on the substrate and covering it with a material capable of converting X-rays into visible light, such as phosphor films (phosphors) or scintillation films (scintillator). Compared with the traditional X-ray sensitive film and a CCD camera focusing fluorescent plate, the indirect detection type image detector has the advantages of transient image acquisition, completely digital image acquisition, small size and low exposure to a patient due to high sensitivity.
The second type of detector is a direct detection type image detector. In such a detector, a semiconductor photoconductive thin film that directly converts X-rays into electrons or holes, such as a semiconductor thin film material of amorphous selenium (a-Se) or lead oxide (PbO), is used instead of a fluorescent film or a scintillator film. The direct detection type image detector has a simple structure, and because light rays in a fluorescent film or a scintillation film are not diffused and scattered, the image resolution is not attenuated, so that a clearer and more precise image can be obtained.
In a direct-detection detector, pixels serve as the basic sensing elements of the detector, and each pixel converts the charge flow of a photoconductor to which it is subjected into an electrical signal. The electrical signals originating from the different pixels are collected during the matrix-reading phase and then processed and stored to be digitized in such a way as to form an image.
However, inside the pixel, the threshold voltage Vth of the tft may shift due to the manufacturing process of the tft, thereby causing some interference to the output signal of the device. In addition, the existing detector manufacturing process also has the problems of large number of masks, high cost, low refresh rate and the like.
Disclosure of Invention
The invention provides a thin film transistor array substrate, a pixel circuit, an X-ray detector and a driving method thereof, aiming at reducing the use of thin film transistors in pixels and reducing the interference of threshold voltage Vth drift of the thin film transistors caused by process problems on device output signals as much as possible by utilizing the basic idea of keeping the thin film transistors for scanning and reading; meanwhile, the invention adopts the photo-induced conductivity effect as the basic principle of the light sensing device to amplify the photo-generated signal in the pixel, thereby improving the gain coefficient of the pixel and improving the output signal of the pixel as much as possible under the condition of unchanged quantum efficiency (EQE); the invention can also increase the pixel filling factor and prevent DQE loss caused by the reduction of the aperture ratio.
The technical scheme of the invention is as follows:
the invention discloses a thin film transistor array substrate, which is used for an X-ray detector and comprises a scanning line and a reading scanning line which are horizontally arranged, a data line and a bias line which are vertically arranged, and a plurality of pixel units which are defined by the scanning line and the data line in a crossed manner, wherein each pixel unit comprises a photoconductive thin film transistor positioned in a photoconductive area and a reading thin film transistor positioned at a reading end, and the pixel unit specifically comprises:
a substrate;
the gate metal layer is positioned above the substrate and comprises a first gate positioned in the photoconductive region and a second gate positioned at a reading end;
the grid insulation layer covers the grid metal layer, and a first opening is formed in the grid insulation layer above the first grid;
a semiconductor layer over the gate insulating layer, including a first semiconductor at the photoconductive region and a second semiconductor at the read terminal;
a source electrode and a drain electrode covering a portion of the semiconductor layer and a portion of the gate insulating layer, the source electrode and the drain electrode being respectively located at both sides of the semiconductor layer;
the first insulating layer covers the grid insulating layer, the source electrode and the drain electrode, and a second opening is formed in the first opening of the first insulating layer;
a first metal layer covering a portion of the first insulating layer and a portion of the first gate electrode at the photoconductive region, the first metal layer being in contact with the first gate electrode within the first opening;
a second insulating layer covering the first insulating layer and the first metal layer;
an organic layer covering the second insulating layer;
the second metal layer covers the organic layer positioned at the reading end;
and a third insulating layer covering the organic layer and the second metal layer.
Preferably, the photoconductive thin film transistor is of a top-gate structure and the reading thin film transistor is of a bottom-gate structure.
Preferably, the material for manufacturing the semiconductor layer is aSi.
Preferably, the first metal layer is made of ITO.
The invention also discloses an X-ray detector which comprises the thin film transistor array substrate.
The invention also discloses a pixel circuit for the X-ray detector, which comprises a photoconductive thin film transistor and a reading thin film transistor,
the gate of the photoconductive thin film transistor is connected with a scanning line, the source of the photoconductive thin film transistor is connected with the drain of the reading thin film transistor, and the drain of the photoconductive thin film transistor is connected with a bias line;
the grid electrode of the reading thin film transistor is connected with a reading scanning line, the source electrode of the reading thin film transistor is connected with a data line, and the drain electrode of the reading thin film transistor is connected with the source electrode of the photoconductive thin film transistor.
The invention also discloses a driving method of the X-ray detector, which adopts the pixel circuit for amplifying the image signal in the pixel, and the driving method is divided into two stages: a read phase and a reset phase; in the same frame, the frame is divided into a plurality of frames,
a reading stage: after a light image is fed, sequentially loading a low level on each row of scanning lines, closing the grid electrode of the photoconductive thin film transistor, sequentially loading a high level on each row of reading scanning lines, opening the grid electrode of the reading thin film transistor, generating a reading voltage difference by the data line and the bias line, outputting an integration current by the integrator and giving an image signal, and after one frame is finished, closing the grid electrode of the reading thin film transistor and closing the light source;
a reset phase: the gate of the photoconductive thin film transistor inputs high-level and low-level pulse signals for resetting;
the next frame is performed and the above process is repeated.
Preferably, the signal amplification factor is increased by prolonging the gate on time of the reading thin film transistor.
Preferably, the signal amplification is increased by increasing the voltage applied to the gate of the photoconductive thin film transistor by the scanning line.
Preferably, the signal amplification is increased by increasing the photoconductive thin film transistor channel area.
The invention can bring at least one of the following beneficial effects:
1. the X-ray detector reads when the X-ray source projects, the X-ray source is not closed, and the flicker frequency of the X-ray source is reduced, so that the refreshing frequency can be further improved;
2. the invention uses the photoconductive effect to replace the photo-voltaic effect of the PIN diode, and can effectively reduce the reaction and storage time;
3. the invention integrates photocurrent and controls amplification factor by utilizing photoconductive effect of an aSi thin film transistor, realizes signal amplification in a pixel, and can realize accurate control of amplification factor while reducing radiation dose;
4. the photoconductive thin film transistor T1 and the reading thin film transistor T2 are designed in the same layer, so that the pixel structure and the process structure are simplified, the use of a photomask is reduced, and the cost is directly reduced;
5. the invention improves the refreshing frequency of the back plate and increases the dynamic display effect.
Drawings
The present invention will be further described in the following detailed description of preferred embodiments, which is to be read in connection with the accompanying drawings.
Fig. 1 is a plan view of a pixel unit of a thin film transistor array substrate according to the present invention;
FIG. 2 is a schematic view of the pixel cell of FIG. 1 along dotted line A-A';
FIG. 3 is an equivalent circuit diagram of the X-ray detector of the present invention under X-ray irradiation conditions;
FIG. 4 is a timing diagram of a pixel circuit according to the present invention.
Detailed Description
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following description will be made with reference to the accompanying drawings. It is obvious that the drawings in the following description are only some examples of the invention, and that for a person skilled in the art, other drawings and embodiments can be derived from them without inventive effort.
For the sake of simplicity, the drawings only schematically show the parts relevant to the present invention, and they do not represent the actual structure as a product. In addition, in order to make the drawings concise and understandable, components having the same structure or function in some of the drawings are only schematically illustrated or only labeled. In this document, "one" means not only "only one" but also a case of "more than one".
The technical solution of the present invention is described in detail with specific examples below.
The invention provides a thin film transistor array substrate for an X-ray detector, which comprises a plurality of scanning lines and a plurality of reading scanning lines which are horizontally arranged, a plurality of data lines and a plurality of Bias lines which are vertically arranged, and a plurality of pixel units which are defined by the intersection of the scanning lines and the data lines, wherein FIG. 1 is a plan view of the pixel units of the thin film transistor array substrate, as shown in FIG. 1, Date and Bias lines are respectively a data line and a Bias line, and Gate _ read are respectively a scanning line and a reading scanning line. Each pixel unit is connected with a scanning line, a reading scanning line, a data line and a bias line.
Wherein each pixel cell includes a photoconductive thin film transistor T1 at the photoconductive region 100 and a read thin film transistor T2 at the read terminal 200. The photoconductive thin film transistor T1 is a top gate structure, and the reading thin film transistor T2 is a bottom gate structure.
Specifically, fig. 2 is a schematic view of the pixel unit in fig. 1 along a dotted line a-a', and as shown in fig. 2, the pixel unit includes: a substrate 01; a gate metal layer 02 over the substrate 01, including a first gate 021 at the photoconductive region 100 and a second gate 022 at the read end 200; the first gate 021 forms a scan line connected to the gate of the photoconductive thin film transistor T1, and the second gate 022 forms the gate of the bottom-gate reading thin film transistor T2. The gate metal layer 02 can be made of Mo, Nb alloy or Cu metal, and the thickness of the film layer is 350-2800A.
The pixel unit further includes: a gate insulating layer 03 covering the gate metal layer 02, wherein a first opening 031 is formed in the gate insulating layer 03 above the first gate 021; a semiconductor layer 04 located above the gate insulating layer 03 and including a first semiconductor 041 located at the photoconductive region 100 and a second semiconductor 042 located at the read terminal 200; a source electrode 051 and a drain electrode 052 covering a portion of the semiconductor layer 04 and a portion of the gate insulating layer 03, the source electrode 051 and the drain electrode 052 being spaced apart from each other and located at both sides of the semiconductor layer 04, respectively; the gate insulating layer 03 can be made of SiN or SiO, and the thickness of the film layer is 550-3575A; the manufacturing material of the semiconductor layer 04 is aSi, and the thickness of the film layer is about 4000A; the source 051 and drain 052 may be made of Mo, Nb alloy or Cu metal, and the thickness of the film layer is 350-2800A.
Note that source 051 and drain 052 overlying the overlapping portions of semiconductor layer 04 form an electrically conductive ohmic contact region where the semiconductor is converted from aSi to n + aSi, which is approximately 300 a thick.
The pixel unit further includes: a first insulating layer 06 covering the gate insulating layer 03, the source 051 and the drain 052, wherein a second opening 061 is arranged on the first opening 031 of the first insulating layer 06; a first metal layer 07 covering a portion of the first insulating layer 06 and a portion of the first gate 021 in the photoconductive region 100, the first metal layer 07 being in contact with the first gate 021 within the first opening 031, a portion of the first metal layer 07 covering the first insulating layer 06 being positioned above the source 051 and the drain 052; a second insulating layer 08 covering the first insulating layer 06 and the first metal layer 07; an organic layer 09 covering the second insulating layer 08; a second metal layer 10 covering the organic layer 09 at the read end 200; and a third insulating layer 11 covering the organic layer 09 and the second metal layer 10. The first insulating layer 06 may be made of SiN, and the thickness of the film layer is 1500-3000 a; the first metal layer 07 may be made of ITO with a film layer thickness of about 1000 a; the second insulating layer 08 may be made of SiN, and the thickness of the film layer is about 2000 a; the organic layer 09 is made of an organic material, and the thickness of the film layer is about 18000A; the second metal layer 10 may be made of Ti, and the thickness of the film layer is about 2000 a; the material of the third insulating layer 11 may be SiN, and the thickness of the film layer is about 5000 a.
It should be noted that the first metal layer 07 is used as a gate of the photoconductive thin film transistor T1 having a top gate structure, and is in contact with the first gate 021 through the first opening 031, and further, since the first metal layer 07 uses an ITO material, the gate of the photoconductive thin film transistor T1 can be used for reset and potential maintenance.
The photoconductive thin film transistor T1 of the present invention adopts a top gate structure, and when the photoconductive thin film transistor T1 is in an off state, the back channel region generates a photoconductive effect on an incident light signal, thereby outputting the signal. The reading thin film transistor T2 of the present invention adopts a conventional bottom gate design, and the top second metal layer 10 is used as a light shielding layer for channel protection.
The invention discloses an X-ray detector which comprises the thin film transistor array substrate 01.
The invention also discloses a pixel circuit which is used for the X-ray detector, fig. 3 is an equivalent circuit diagram of the X-ray detector under the X-ray irradiation condition, Date and Bias lines are respectively a data line and a Bias line, and Gate _ read are respectively a scanning line and a reading scanning line. As shown in fig. 3, the pixel circuit includes a photoconductive thin film transistor T1 and a reading thin film transistor T2.
The gate of the photoconductive thin film transistor T1 is connected to a scan line, the source 051 of the photoconductive thin film transistor T1 is connected to the drain 052 of the reading thin film transistor T2, and the drain 052 of the photoconductive thin film transistor T1 is connected to a bias line.
A gate of the reading thin film transistor T2 is connected to a reading scan line, a source 051 of the reading thin film transistor T2 is connected to a data line, and a drain 052 of the reading thin film transistor T2 is connected to a source 051 of the photoconductive thin film transistor T1.
The invention also comprises a driving method of the X-ray detector, which adopts the pixel circuit and is used for amplifying the image signals in the pixels. Fig. 4 is a timing diagram of the pixel circuit, wherein Vdate and Vbias are output signals of the data line and the bias line, Vgate is an output signal of the scan line, and lighting is an input signal of the light source. As shown in fig. 4, the driving method is divided into two stages: a read phase and a reset phase. Within the same frame:
a reading stage: when a light image is applied, each row of scanning lines is sequentially applied with a low level, the gate of the photoconductive thin film transistor T1 is turned off, and the back channel region of the photoconductive thin film transistor T1 displays an insulator, but the back channel region is exposed to light, and the photosensitive conductivity of the back channel region gradually increases as the light source continues to apply photoelectrons. Each row of reading scanning lines are loaded with high level in sequence, the grid electrode of the reading thin film transistor T2 is opened, at the moment, because the second metal layer 10 is arranged above the reading thin film transistor T2 to serve as a shading layer, the back channel region of the reading thin film transistor T2 is not photosensitive, and because the light source is continuously fed in the whole reading process, a reading voltage difference Vdata-bias is generated between the data line and the bias line, then the source electrode 051 driving circuit outputs an integral current and gives an image signal, and after one frame is finished, the grid electrode of the reading thin film transistor T2 is closed, and the light source is closed. It should be noted that, during the whole reading period, the gate of the photoconductive thin film transistor T1 is in the off state, and the light source is not turned off, so as to reduce the flicker frequency of the light source, which is generally referred to as an X-ray source, and further increase the refresh frequency.
The resistance of the reading voltage difference Vdata-bias is mainly the on-state resistance of the reading thin film transistor T2 and the off-state resistance of the photoconductive thin film transistor T1, the resistances have different magnitudes due to the change of the light intensity, and generally, the integrated current output by the source 051 driving circuit is about uA level.
A reset phase: the gate of the photoconductive thin film transistor T1 is input with high and low level pulse signals for reset. After one frame scanning is completed, the gates of the photoconductive thin film transistors T1 of all pixels of the entire display area are first inputted with a high level, at which time the back channel of the photoconductive thin film transistor T1 is reset, and then the gate of the photoconductive thin film transistor T1 is inputted with a low level.
Finally, the next frame is carried out and the process is repeated.
Preferably, in order to increase the signal amplification factor, the present invention may increase the signal amplification factor by increasing the gate on time of the reading tft T2, increasing the reading voltage difference Vdata-bias, and increasing the integration time, and further increasing the output magnitude of the integration current. Alternatively, the present invention may increase the signal amplification factor by increasing the voltage applied to the gate of the photoconductive thin film transistor T1 by the scanning line, thereby reducing the noise.
The invention can effectively reduce the reaction and storage time, further improve the refresh frequency and realize dynamic display by reasonably controlling the opening time of the reading thin film transistor T2, the loading voltage of the bias line and the size of the photoconductive thin film transistor T1.
Different from the common multi-TFT amplification principle, the X-ray detector of the invention adopts the photoconductive thin film transistor T1 and the reading thin film transistor T2 on the thin film transistor array substrate, and substitutes the photoconductive effect for the PIN diode photovoltaic effect, thereby effectively reducing the reaction and storage time. The invention integrates photocurrent and controls amplification factor by utilizing photoconductive effect of an aSi thin film transistor, realizes signal amplification in a pixel, and can realize accurate control of amplification factor while reducing radiation dose.
In addition, the photoconductive thin film transistor T1 and the reading thin film transistor T2 are designed in the same layer, so that the pixel structure and the process structure are simplified, the use of a photomask is reduced, and the cost is directly reduced.
It should be noted that the above mentioned embodiments are only preferred embodiments of the present invention, but the present invention is not limited to the details of the above embodiments, and it should be noted that, for those skilled in the art, it is possible to make various modifications and amendments within the technical concept of the present invention without departing from the principle of the present invention, and various modifications, amendments and equivalents of the technical solution of the present invention should be regarded as the protection scope of the present invention.
Claims (7)
1. A thin film transistor array substrate for an X-ray detector comprises a scanning line and a reading scanning line which are horizontally arranged, a data line and a bias line which are vertically arranged, and a plurality of pixel units defined by the intersection of the scanning line and the data line, wherein each pixel unit comprises a photoconductive thin film transistor positioned in a photoconductive area and a reading thin film transistor positioned at a reading end, and the pixel unit specifically comprises:
a substrate;
the gate metal layer is positioned above the substrate and comprises a first gate positioned in the photoconductive region and a second gate positioned at a reading end;
the grid insulation layer covers the grid metal layer, and a first opening is formed in the grid insulation layer above the first grid;
a semiconductor layer over the gate insulating layer, including a first semiconductor at the photoconductive region and a second semiconductor at the read terminal;
a source electrode and a drain electrode covering a portion of the semiconductor layer and a portion of the gate insulating layer, the source electrode and the drain electrode being respectively located at both sides of the semiconductor layer;
the first insulating layer covers the grid insulating layer, the source electrode and the drain electrode, and a second opening is formed in the first opening of the first insulating layer;
a first metal layer covering a portion of the first insulating layer and a portion of the first gate electrode at the photoconductive region, the first metal layer being in contact with the first gate electrode within the first opening;
a second insulating layer covering the first insulating layer and the first metal layer;
an organic layer covering the second insulating layer;
the second metal layer covers the organic layer positioned at the reading end;
and a third insulating layer covering the organic layer and the second metal layer.
2. The thin film transistor array substrate of claim 1, wherein the photoconductive thin film transistor is a top gate structure and the reading thin film transistor is a bottom gate structure.
3. The thin film transistor array substrate of claim 1, wherein the semiconductor layer is made of aSi.
4. The thin film transistor array substrate of claim 1, wherein the first metal layer is made of ITO.
5. An X-ray detector comprising the thin film transistor array substrate according to any one of claims 1 to 4.
6. A pixel circuit for use in the X-ray detector of claim 5, comprising a photoconductive thin film transistor and a reading thin film transistor,
the gate of the photoconductive thin film transistor is connected with a scanning line, the source of the photoconductive thin film transistor is connected with the drain of the reading thin film transistor, and the drain of the photoconductive thin film transistor is connected with a bias line;
the grid electrode of the reading thin film transistor is connected with a reading scanning line, the source electrode of the reading thin film transistor is connected with a data line, and the drain electrode of the reading thin film transistor is connected with the source electrode of the photoconductive thin film transistor.
7. A driving method of an X-ray detector for amplifying an image signal in a pixel using the pixel circuit of claim 6, wherein the driving method is divided into two stages: a read phase and a reset phase; in the same frame, the frame is divided into a plurality of frames,
a reading stage: after a light image is fed, sequentially loading a low level on each row of scanning lines, closing the grid electrode of the photoconductive thin film transistor, sequentially loading a high level on each row of reading scanning lines, opening the grid electrode of the reading thin film transistor, generating a reading voltage difference by the data line and the bias line, outputting an integration current by the integrator and giving an image signal, and after one frame is finished, closing the grid electrode of the reading thin film transistor and closing the light source;
a reset phase: the gate of the photoconductive thin film transistor inputs high-level and low-level pulse signals for resetting;
the next frame is performed and the above process is repeated.
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| CN113740357A (en) * | 2021-08-25 | 2021-12-03 | 江苏尚飞光电科技股份有限公司 | Novel X-ray dual-energy detector and imaging method and imaging system thereof |
| WO2023108607A1 (en) * | 2021-12-17 | 2023-06-22 | 京东方科技集团股份有限公司 | Detection substrate, noise reduction method therefor and detection apparatus |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20030058539A (en) * | 2001-12-31 | 2003-07-07 | 비오이 하이디스 테크놀로지 주식회사 | method for fabricating digital X-ray detector |
| KR20040041253A (en) * | 2002-11-09 | 2004-05-17 | 엘지.필립스 엘시디 주식회사 | A X-ray detector and a method for fabricating thereof |
| CN101308856A (en) * | 2007-05-14 | 2008-11-19 | 三菱电机株式会社 | Optical sensor |
| CN104795419A (en) * | 2015-05-11 | 2015-07-22 | 京东方科技集团股份有限公司 | X-ray flat panel detector |
| CN105453269A (en) * | 2013-08-07 | 2016-03-30 | 夏普株式会社 | X-ray image sensor substrate |
| KR20180044678A (en) * | 2016-10-24 | 2018-05-03 | 엘지디스플레이 주식회사 | Digital x-ray detector |
-
2020
- 2020-10-28 CN CN202011169485.9A patent/CN112002721B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20030058539A (en) * | 2001-12-31 | 2003-07-07 | 비오이 하이디스 테크놀로지 주식회사 | method for fabricating digital X-ray detector |
| KR20040041253A (en) * | 2002-11-09 | 2004-05-17 | 엘지.필립스 엘시디 주식회사 | A X-ray detector and a method for fabricating thereof |
| CN101308856A (en) * | 2007-05-14 | 2008-11-19 | 三菱电机株式会社 | Optical sensor |
| CN105453269A (en) * | 2013-08-07 | 2016-03-30 | 夏普株式会社 | X-ray image sensor substrate |
| CN104795419A (en) * | 2015-05-11 | 2015-07-22 | 京东方科技集团股份有限公司 | X-ray flat panel detector |
| KR20180044678A (en) * | 2016-10-24 | 2018-05-03 | 엘지디스플레이 주식회사 | Digital x-ray detector |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113740357A (en) * | 2021-08-25 | 2021-12-03 | 江苏尚飞光电科技股份有限公司 | Novel X-ray dual-energy detector and imaging method and imaging system thereof |
| WO2023108607A1 (en) * | 2021-12-17 | 2023-06-22 | 京东方科技集团股份有限公司 | Detection substrate, noise reduction method therefor and detection apparatus |
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| CN112002721B (en) | 2020-12-29 |
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