A flat panel detector, a radiographic imaging device and a driving method thereof

Abstract

A flat panel detector, a radiographic imaging device and a driving method thereof provided by the present disclosure include: a plurality of detection pixel units arranged in an array, a gate driving circuit, a residual image acquisition circuit, a system circuit and a reading circuit; wherein, the gate driving circuit is electrically connected to each row of detection pixel units respectively; the residual image acquisition circuit is electrically connected to each row of detection pixel units respectively, and the residual image acquisition circuit is configured to read the residual image signal of the detection pixel unit; the system circuit is electrically connected to the residual image acquisition circuit and the reading circuit respectively, and the system circuit is configured to control whether the reading circuit reads the image signal of the detection pixel unit according to the residual image signal of the detection pixel unit.

Description

Technical Field

[0001] The present invention relates to the field of display technologies, and in particular, to a flat panel detector, a ray imaging device, and a driving method thereof. Background Art

[0002] X-rays are electromagnetic waves with extremely short wavelengths and high energies. The wavelengths of X-rays are shorter than those of visible light (about 0.001 nm - 100 nm, and the wavelengths of X-rays used in medicine are about between 0.001 nm and 0.1 nm), and the photon energies of X-rays are tens of thousands to hundreds of thousands of times greater than those of visible light. Discovered by the German physicist W.K. Röntgen in 1895, they are also known as Röntgen rays. X-rays have a high penetration ability and can penetrate many substances that are opaque to visible light, such as black paper and wood.

[0003] The detection principle of an X-ray flat panel detector utilizes the characteristic that X-rays have different penetration abilities for tissues of different materials. The amorphous silicon flat panel detector is for indirect digital X-ray imaging. Its basic structure is that the surface is a layer of scintillator material (cesium iodide or thioxide), the next layer is a photodiode circuit made of amorphous silicon, and the bottom layer is a charge readout circuit.

[0004] The scintillator located on the surface of the X-ray flat panel detector converts the X-rays attenuated after passing through the human body into visible light. The amorphous silicon photodiode array under the scintillator then converts the visible light into an electrical signal, forming stored charges on the capacitance of the photodiode itself. The stored charge amount of each photodiode is proportional to the incident X-ray intensity. By scanning and reading out the stored charges of each photodiode, after analog-to-digital (A / D) conversion, digital signals are output and sent to a computer for image processing to form an X-ray digital image. Summary of the Invention

[0005] Embodiments of the present invention provide a flat panel detector, a ray imaging device, and a driving method thereof to improve the automatic image acquisition quality of the flat panel detector.

[0006] Therefore, a flat panel detector provided by an embodiment of the present invention includes:

[0007] A plurality of detection pixel units arranged in an array, a gate driving circuit, a residual image acquisition circuit, a system circuit, and a reading circuit; wherein,

[0008] The gate driving circuit is electrically connected to each row of the detection pixel units respectively;

[0009] The residual image acquisition circuit is electrically connected to each row of the detection pixel units respectively, and the residual image acquisition circuit is configured to read the residual image signals of the detection pixel units;

[0010] The system circuit is electrically connected to the afterimage acquisition circuit and the reading circuit respectively. The system circuit is configured to control whether the reading circuit reads the image signal of the detection pixel unit according to the afterimage signal of the detection pixel unit.

[0011] Optionally, in the above flat panel detector provided by the embodiments of the present invention, the afterimage acquisition circuit is specifically configured to read the afterimage signals of the detection pixel units row by row;

[0012] The system circuit is specifically configured to determine whether the difference between the afterimage signal of the detection pixel unit in the current row minus the afterimage signal of the detection pixel unit in the previous row is greater than a first threshold or less than a second threshold. When it is determined to be greater than the first threshold, a first control signal is sent to the reading circuit. When it is determined to be less than the second threshold, a second control signal is sent to the reading circuit;

[0013] The reading circuit is specifically configured to read the image signal of the detection pixel unit under the action of the first control signal and stop reading the image signal of the detection pixel unit under the action of the second control signal.

[0014] Optionally, in the above flat panel detector provided by the embodiments of the present invention, it further includes a plurality of gate lines and a plurality of reading lines arranged crosswise. The plurality of reading lines include a plurality of first reading lines and a plurality of second reading lines;

[0015] The detection pixel unit includes: a first transistor, a second transistor, and a photodiode;

[0016] In the detection pixel unit, the first pole of the first transistor, the first pole of the second transistor, and the first electrode of the photodiode are electrically connected, and a negative level is applied to the second electrode of the photodiode;

[0017] The gates of all the first transistors in the detection pixel units of the same row are electrically connected to the gate driving circuit through one of the gate lines, and the second poles of all the first transistors in the detection pixel units of the same column are electrically connected to the reading circuit through one of the second reading lines;

[0018] The gates of all the second transistors in the detection pixel units of the same row are electrically connected to the gate driving circuit through one of the gate lines, and in adjacent rows, the gates of all the second transistors in the detection pixel units of the upper row and the gates of all the first transistors in the detection pixel units of the lower row share one of the gate lines; the second poles of all the second transistors in the detection pixel units of the same column are electrically connected to the afterimage acquisition circuit through one of the first reading lines.

[0019] Optionally, in the above-mentioned flat panel detector provided by the embodiments of the present invention, the afterimage acquisition circuit includes: a first amplifier, a first integration capacitor, a first capacitor, a second capacitor, a third capacitor, a first switch, a second switch, a third switch, a fourth switch, a resistor, a data selector, an analog-to-digital converter, and a data interface;

[0020] The inverting input terminal of the first amplifier is connected to the detection pixel unit, and a variable frequency signal is loaded on the non-inverting input terminal of the first amplifier;

[0021] The first integration capacitor is connected between the inverting input terminal and the output terminal of the first amplifier;

[0022] The first switch is arranged in parallel with the first integration capacitor;

[0023] The second switch is connected in parallel with the resistor;

[0024] The third switch is connected in series between the first end of the resistor and the first pole of the first capacitor;

[0025] The fourth switch is connected in series between the first end of the resistor and the first pole of the second capacitor;

[0026] The second end of the resistor is electrically connected to the output terminal of the first amplifier;

[0027] The first pole of the first capacitor is electrically connected to the first input terminal of the data selector;

[0028] The first pole of the second capacitor is electrically connected to the second input terminal of the data selector;

[0029] The second pole of the first capacitor, the second pole of the second capacitor, and the second pole of the third capacitor are grounded;

[0030] The output terminal of the data selector is electrically connected to the first input terminal of the analog-to-digital converter, the output terminal of the digital-to-analog converter is electrically connected to the input terminal of the data interface, and a fixed positive level is loaded on the second input terminal of the digital-to-analog converter and the first pole of the third capacitor;

[0031] The output terminal of the data interface is electrically connected to the system circuit.

[0032] Optionally, in the above-mentioned flat panel detector provided by the embodiments of the present invention, the reading circuit includes a plurality of sub-circuits, and each of the sub-circuits is electrically connected to a column of the detection pixel units;

[0033] The sub-circuit includes a second amplifier, a second integration capacitor, and a fifth switch. Among them, the inverting input terminal of the second amplifier is connected to the detection pixel unit, the non-inverting input terminal of the second amplifier is loaded with a reference signal, the second integration capacitor is connected between the inverting input terminal and the output terminal of the second amplifier, and the fifth switch is arranged in parallel with the second integration capacitor.

[0034] Based on the same inventive concept, an embodiment of the present invention provides a ray imaging device, including: a handle, a ray generator, a host computer, and the above-mentioned flat panel detector; among them,

[0035] The handle is electrically connected to the ray generator through a communication line. The flat panel detector is independently arranged with respect to the handle and the ray generator, and the flat panel detector communicates with the host computer in a wireless or wired manner.

[0036] Based on the same inventive concept, an embodiment of the present invention provides a driving method for the above-mentioned ray imaging device, including:

[0037] The gate driving circuit drives the detection pixel unit to open. The afterimage acquisition circuit reads the afterimage signal of the detection pixel unit and sends the afterimage signal of the detection pixel unit to the system circuit in real time;

[0038] Use the handle to control the ray generator to emit rays;

[0039] The system circuit controls whether the reading circuit reads the image signal of the detection pixel unit according to the afterimage signal of the detection pixel unit;

[0040] The host computer processes and forms an image of the image signal of the detection pixel unit read by the reading circuit.

[0041] Optionally, in the above driving method provided by the embodiment of the present invention, the afterimage acquisition circuit reads the afterimage signal of the detection pixel unit, specifically including:

[0042] The afterimage acquisition circuit reads the afterimage signal of the detection pixel unit row by row.

[0043] Optionally, in the above driving method provided by the embodiment of the present invention, the system circuit controls whether the reading circuit reads the image signal of the detection pixel unit according to the afterimage signal of the detection pixel unit, specifically including:

[0044] The system circuit determines whether the difference between the afterimage signal of the detection pixel unit in the current row minus the afterimage signal of the detection pixel unit in the previous row is greater than a first threshold, and when it is determined to be greater than the first threshold, sends a first control signal to the reading circuit;

[0045] The reading circuit reads the image signals of the detection pixel units row by row under the action of the first control signal, and sends the read image signals of the detection pixel units to the host computer.

[0046] Optionally, in the above driving method provided by the embodiments of the present invention, while the reading circuit reads the image signals of the detection pixel units row by row under the action of the first control signal, it further includes:

[0047] The gate driving circuit drives the detection pixel units to be turned on row by row, the afterimage acquisition circuit reads the afterimage signals of the detection pixel units row by row, and sends the afterimage signals of each row of the detection pixel units to the system circuit in real time;

[0048] The system circuit determines whether the difference between the afterimage signal of the detection pixel units in the current row minus the afterimage signal of the detection pixel units in the previous row is less than a second threshold, and when it is determined that it is less than the second threshold, sends a second control signal to the reading circuit;

[0049] The reading circuit stops reading the image signals of the detection pixel units under the action of the second control signal.

[0050] Optionally, in the above driving method provided by the embodiments of the present invention, when the system circuit sends a first control signal to the reading circuit, it further includes:

[0051] The system circuit sends instructions to the gate driving circuit and the afterimage acquisition circuit to start working simultaneously with the reading circuit.

[0052] Optionally, in the above driving method provided by the embodiments of the present invention, the system circuit sends a first control signal to the reading circuit, specifically including:

[0053] The system circuit sends a first control signal to the reading circuit to start working after a preset time, and the preset time is the integration time set for image acquisition.

[0054] The beneficial effects of the present invention are as follows:

[0055] A flat panel detector, a ray imaging device and a driving method thereof provided by an embodiment of the present invention include: a plurality of detection pixel units arranged in an array, a gate driving circuit, a residual image acquisition circuit, a system circuit and a reading circuit; wherein, the gate driving circuit is electrically connected to each row of detection pixel units respectively; the residual image acquisition circuit is electrically connected to each row of detection pixel units respectively, and the residual image acquisition circuit is configured to read the residual image signal of the detection pixel unit; the system circuit is electrically connected to the residual image acquisition circuit and the reading circuit respectively, and the system circuit is configured to control whether the reading circuit reads the image signal of the detection pixel unit according to the residual image signal of the detection pixel unit. By continuously driving the detection pixel unit to be turned on by the gate driving circuit, the residual image acquisition circuit continuously transmits the acquired residual image signal to the system circuit. When the X-ray starts to expose, the residual image acquisition circuit will acquire a larger residual image signal and transmit it to the system circuit. The system circuit can then control whether the reading circuit reads the image signal according to the residual image signal, realizing the automatic image acquisition function. Thus, it can be seen that in the present invention, the residual image signal that originally had a negative impact on the image is transformed into a signal that has a positive effect on automatic image acquisition, not only solving the influence of the residual image signal on the image acquisition quality, but also enabling the reading circuit to work only during automatic image acquisition, effectively avoiding the influence of the temperature drift generated by the long-term operation of the reading circuit on the automatic image acquisition quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 is a schematic structural diagram of a flat panel detector in the related art;

[0057] Figure 2 is a schematic structural diagram of a flat panel detector provided by an embodiment of the present invention;

[0058] Figure 3 is another schematic structural diagram of a flat panel detector provided by an embodiment of the present invention;

[0059] Figure 4 is a working timing diagram of the residual image acquisition circuit provided by an embodiment of the present invention;

[0060] Figure 5 is a schematic structural diagram of a ray imaging device provided by an embodiment of the present invention;

[0061] Figure 6 is a flowchart of a driving method of a ray imaging device provided by an embodiment of the present invention;

[0062] Figure 7 is a working timing diagram of a flat panel detector provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0063] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions of the embodiments of the present invention in conjunction with the accompanying drawings of the embodiments of the present invention. It should be noted that the sizes and shapes of the various figures in the drawings do not reflect the true proportions, and the purpose is only to schematically illustrate the content of the present invention. Also, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0064] Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meaning as understood by those of ordinary skill in the art to which the present invention pertains. The terms "first", "second", and similar terms used in the description and claims of the present invention do not denote any order, quantity, or importance, but are only used to distinguish different components. The terms "comprising", "including", or similar terms mean that the elements or items appearing before the term cover the elements or items listed after the term and their equivalents, without excluding other elements or items. The terms "inside", "outside", "above", "below", etc. are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0065] Figure 1 It is a schematic structural diagram of a flat panel detector in the related art. In Figure 1 the shown flat panel detector, the levels of the SD point and the P1 point are mostly 1V. When the photodiode PD is in a reverse bias state of -7V, electrons can be generated under light illumination. Most of the electrons generated by light illumination gather at the P1 point. After the exposure ends, the electrons at the P1 point (i.e., the image signal) are read, and then the read electrons are converted into gray values for imaging; however, a small portion of the electrons (i.e., the ghost signal) will remain in the photodiode PD and cannot be discharged in time. Therefore, after the flat panel detector receives an X-ray exposure and completes image acquisition, there will be charge residues of the previous exposure image in the photodiode PD, which affects the quality of the next frame of image acquisition and makes it impossible for doctors to accurately judge the condition.

[0066] In addition, most flat panel detectors in the related art do not have the function of automatically capturing images after sensing X-ray exposure; a small number of flat panel detectors can only continuously collect signals through a readout integrated circuit (ROIC) and achieve automatic image capture by judging signal changes. This automatic exposure control (AEC) method requires the ROIC to work continuously, and the power consumption of the ROIC is relatively large during operation, and the heat generation is also relatively serious. Being in a working state for a long time will cause a significant increase in temperature, and the collected grayscale images will be affected by the temperature. The increase in temperature will affect the accuracy of the captured images, thereby affecting the doctor's judgment of the condition.

[0067] In order to at least solve the above technical problems existing in the related art, the embodiments of the present disclosure provide a flat panel detector, as Figure 2 shown, which may include:

[0068] A plurality of detection pixel units 101 arranged in an array, a gate driving circuit 102, a residual image acquisition circuit 103, a system circuit 104, and a readout circuit 105; wherein,

[0069] The gate driving circuit 102 is electrically connected to each row of detection pixel units 101 respectively;

[0070] The residual image acquisition circuit 103 is electrically connected to each row of detection pixel units 101 respectively, and the residual image acquisition circuit 103 is configured to read the residual image signal of the detection pixel unit 101;

[0071] The system circuit 104 is electrically connected to the residual image acquisition circuit 103 and the readout circuit 105 respectively, and the system circuit 104 is configured to control whether the readout circuit 105 reads the image signal of the detection pixel unit 101 according to the residual image signal of the detection pixel unit 101.

[0072] In the above flat panel detector provided by the embodiments of the present invention, the gate driving circuit 102 continuously drives the detection pixel unit 101 to open, and the residual image acquisition circuit 103 continuously transmits the collected residual image signal to the system circuit 104. When the X-ray starts to expose, the residual image acquisition circuit 103 will collect a larger residual image signal and transmit it to the system circuit 104. The system circuit 104 can then control whether the readout circuit 105 reads the image signal according to the residual image signal, realizing the automatic image capture function. Thus, it can be seen that in the present invention, the residual image signal that originally had a negative impact on the image is transformed into a signal that has a positive effect on automatic image capture, not only solving the influence of the residual image signal on the image capture quality, but also enabling the readout circuit to work only during automatic image capture, effectively avoiding the influence of temperature drift generated by the long-term operation of the readout circuit on the automatic image capture quality.

[0073] Before the X-ray starts to expose, the afterimage acquisition circuit 103 will acquire a relatively small afterimage signal; when the X-ray starts to expose, the afterimage acquisition circuit 103 will acquire a relatively large afterimage signal; after the X-ray exposure ends, the afterimage acquisition circuit 103 will acquire a relatively small afterimage signal again. Therefore, by judging the difference between the two acquired afterimage signals, it is possible to control whether the reading circuit 105 reads the image signal.

[0074] Based on this, in the above-mentioned flat panel detector provided by the embodiment of the present invention, the afterimage acquisition circuit can be specifically configured to read the afterimage signals of the detection pixel units 101 row by row;

[0075] The system circuit can be specifically configured to judge whether the difference between the afterimage signal of the current row of detection pixel units 101 minus the afterimage signal of the previous row of detection pixel units 101 is greater than a first threshold or less than a second threshold, and when it is determined to be greater than the first threshold, send a first control signal to the reading circuit 105, and when it is determined to be less than the second threshold, send a second control signal to the reading circuit 105;

[0076] The reading circuit 105 can be specifically configured to read the image signals of the detection pixel units 101 under the action of the first control signal and stop reading the image signals of the detection pixel units 101 under the action of the second control signal.

[0077] In some embodiments, in the above-mentioned flat panel detector provided by the embodiment of the present invention, as Figure 2 shown, it may further include a plurality of gate lines 106 and a plurality of reading lines 107 arranged crosswise, and the plurality of reading lines 107 may include a plurality of first reading lines 1071 and a plurality of second reading lines 1072;

[0078] The detection pixel unit 101 may include: a first transistor T1, a second transistor T2, and a photodiode PD;

[0079] In the detection pixel unit 101, the first pole of the first transistor T1, the first pole of the second transistor T2, and the first electrode of the photodiode PD are electrically connected, and a negative level is applied to the second electrode of the photodiode PD. In some embodiments, the value range of this negative level may be between -4V and -8V;

[0080] The gates of all the first transistors T1 in the same row of detection pixel units 101 are electrically connected to the gate driving circuit 102 through a gate line 106, and the second poles of all the first transistors T1 in the same column of detection pixel units 101 are electrically connected to the reading circuit 105 through a second reading line 1072;

[0081] The gates of all the second transistors T2 in the peer detection pixel unit 101 are electrically connected to the gate driving circuit 102 through a gate line 106. In adjacent rows, the gates of all the second transistors T2 in the upper row of detection pixel units 101 share a gate line 106 with the gates of all the first transistors T1 in the lower row of detection pixel units 102; the second poles of all the second transistors T2 in the same column of detection pixel units 101 are electrically connected to the afterimage acquisition circuit 103 through a first read line 1071.

[0082] In some embodiments, in the above flat panel detector provided by the embodiments of the present invention, as Figure 3 shown, the afterimage acquisition circuit 103 may include: a first amplifier AMP1, a first integration capacitor C F1 , a first capacitor C1, a second capacitor C2, a third capacitor C3, a first switch Instrst, a second switch FA, a third switch CDS1, a fourth switch CDS2, a resistor LRF, a data selector MUX, an analog-to-digital converter ADC, and a data interface DP (Data Processing);

[0083] The inverting input terminal Vin of the first amplifier AMP1 is connected to the detection pixel unit 101, and the non-inverting input terminal Vo of the first amplifier AMP1 is loaded with a frequency conversion signal; in some embodiments, the low-frequency level of the frequency conversion signal may be the same as the reference signal of the read circuit 105, for example, it may be 0V, so as to function as a recovery level before the second transistor T2 is turned off; the high-frequency level of the frequency conversion signal may be 5V, which can apply a relatively high reverse bias voltage to the photodiode PD after the second transistor T2 is turned on, promoting more thorough elimination of residual electrons;

[0084] The first integration capacitor C F1 is connected between the inverting input terminal Vin and the output terminal Vout of the first amplifier AMP1;

[0085] The first switch Intrst is arranged in parallel with the first integration capacitor C F1 ;

[0086] The second switch FA is arranged in parallel with the resistor LRF;

[0087] The third switch CDS1 is connected in series between the first end of the resistor LRF and the first pole of the first capacitor C1;

[0088] The fourth switch CDS2 is connected in series between the first end of the resistor LRF and the first pole of the second capacitor C2;

[0089] The second end of the resistor LRF is electrically connected to the output terminal Vout of the first amplifier AMP1;

[0090] The first pole of the first capacitor C1 is electrically connected to the first input terminal of the data selector MUX;

[0091] The first pole of the second capacitor C2 is electrically connected to the second input terminal of the data selector MUX;

[0092] The second poles of the first capacitor C1, the second capacitor C2, and the third capacitor C3 are grounded;

[0093] The output terminal of the data selector MUX is electrically connected to the first input terminal of the analog-to-digital converter AMP1, the output terminal of the analog-to-digital converter AMP1 is electrically connected to the input terminal of the data interface DP, and a fixed positive level (e.g., 4.096V) is applied to the second input terminal of the analog-to-digital converter AMP1 and the first pole of the third capacitor C3;

[0094] The output terminal of the data interface DP is electrically connected to the system circuit 104.

[0095] In a specific implementation, as Figure 4 shown, under the trigger of the acquisition cycle start signal SYNC, the first switch Instrst resets the first integration capacitor C F1 . During the process of acquiring the afterimage signal, the first integration capacitor C F1 and the first amplifier AMP1 integrate the afterimage signal in the same row of detection pixel units 101 and convert it into a corresponding level output to the resistor LRF for low-pass filtering. The second switch CDS1, the third switch CDS2, the first capacitor C1, the second capacitor C2, and the data selector MUX perform noise reduction on the afterimage signal after low-pass filtering, and then send it to the analog-to-digital converter ADC for analog-to-digital conversion into a data signal, which is then sent to the system circuit 104 in real time by the data interface DP. It should be noted that, as Figure 4 shown, in order to implement the noise reduction function, the high-level duration of the fourth switch CDS2 should be less than the duration of the high-frequency signal applied to the non-inverting input terminal Vo of the first amplifier AMP1.

[0096] In some embodiments, in the above flat panel detector provided by the embodiments of the present invention, as Figure 3 shown, the reading circuit 105 may include multiple sub-circuits 1051, and each sub-circuit 1051 is electrically connected to a column of detection pixel units 101;

[0097] The sub-circuit 1051 includes a second amplifier AMP2, a second integration capacitor C F2 and a fifth switch SW. Among them, the inverting input terminal of the second amplifier AMP2 is connected to the detection pixel unit 101, the non-inverting input terminal of the second amplifier AMP2 is loaded with a reference signal Ref, and the second integration capacitor C F2Connected between the inverting input terminal of the second amplifier AMP2 and the output terminal of the second amplifier AMP2, the fifth switch SW is arranged in parallel with the second integration capacitor C F2 in parallel.

[0098] Each sub-circuit 1051 can integrate the image signals in a column of electrically connected detection pixel units 101 and convert them into corresponding level outputs.

[0099] The above is only an example to illustrate the specific structures of the afterimage acquisition circuit 104 and the reading circuit 105 in the flat panel detector provided by the present invention. In specific implementation, the specific structures of the afterimage acquisition circuit 104 and the reading circuit 105 are not limited to the above structures provided by the specific embodiments of the present invention, and may also be other structures known to those skilled in the art, which are not limited herein.

[0100] It should be noted that the transistors mentioned in the above specific embodiments of the present invention may be thin film transistors (TFT, Thin Film Transistor), or metal oxide semiconductor field effect transistors (MOS, Metal Oxide Semiconductor), which are not limited herein. In specific implementation, the first pole and the second pole of these transistors can be interchanged without specific distinction.

[0101] Based on the same inventive concept, an embodiment of the present invention further provides a ray imaging device, including the above flat panel detector, which can be used for static image acquisition (such as radiography) and / or dynamic acquisition (such as fluoroscopy during surgery). Since the principle of solving problems of this ray imaging device is similar to that of the above flat panel detector, therefore, the implementation of this ray imaging device provided by the embodiment of the present invention can refer to the implementation of the above flat panel detector provided by the embodiment of the present invention, and the repeated parts will not be described again.

[0102] Specifically, as Figure 5 shown, the ray imaging device provided by the embodiment of the present invention may include: a handle 01, a ray generator 02, a host computer 03, and the above flat panel detector 04; wherein, the handle 01 is electrically connected to the ray generator 02 through a communication line 05, the flat panel detector 04 is independently arranged with respect to the handle 01 and the ray generator 02, and the flat panel detector 04 communicates with the host computer 03 in a wireless or wired manner.

[0103] In the ray imaging device of the related art, the handle 01 is electrically connected to the ray generator 02 and the flat panel detector 04 by communication traces, and the handle 01 is used to control the ray generator 02 to emit rays and control the flat panel detector 04 to collect images. In this case, not only complex interfaces and circuit designs are required, increasing the cost, but also the portability of the product is limited. In the ray imaging device provided by the present invention, since the flat panel detector 04 can automatically acquire images, it is not necessary to control it through the handle 01. Therefore, communication traces 05 can be provided only between the handle 01 and the ray generator 02, thereby saving costs and improving the portability of the product.

[0104] Correspondingly, for the above ray imaging device provided by the embodiments of the present invention, the embodiments of the present invention also provide a driving method, as Figure 6 shown, which may include the following steps:

[0105] S601. The gate drive circuit drives the detection pixel unit to open, the afterimage acquisition circuit reads the afterimage signal of the detection pixel unit, and sends the afterimage signal of the detection pixel unit to the system circuit in real time;

[0106] S602. Use the handle to control the ray generator to emit rays;

[0107] S603. The system circuit controls whether the reading circuit reads the image signal of the detection pixel unit according to the afterimage signal of the detection pixel unit;

[0108] S604. The host computer processes and images the image signal of the detection pixel unit read by the reading circuit.

[0109] In some embodiments, in the above driving method provided by the embodiments of the present invention, in step S601, the afterimage acquisition circuit reads the afterimage signal of the detection pixel unit, which can be specifically implemented in the following manner:

[0110] The afterimage acquisition circuit reads the afterimage signals of the detection pixel units row by row, which can increase the intensity of the afterimage signals and facilitate the detection of the afterimage signals.

[0111] In some embodiments, in the above driving method provided by the embodiments of the present invention, in step S603, the system circuit controls whether the reading circuit reads the image signal of the detection pixel unit according to the afterimage signal of the detection pixel unit, which can be specifically implemented in the following manner:

[0112] The system circuit determines whether the difference between the afterimage signal of the detection pixel unit in the current row minus the afterimage signal of the detection pixel unit in the previous row is greater than a first threshold, and when it is determined to be greater than the first threshold, sends a first control signal to the reading circuit; in some embodiments, the first threshold may be greater than the noise signal and less than the afterimage signal;

[0113] The reading circuit reads the image signals of the detection pixel units row by row under the action of the first control signal, and sends the read image signals of the detection pixel units to the host computer, so that the automatic image acquisition function can be realized.

[0114] In some embodiments, in the above driving method provided by the embodiments of the present invention, while the reading circuit reads the image signals of the detection pixel units row by row under the action of the first control signal, the following steps can also be performed:

[0115] The gate driving circuit drives the detection pixel units to be turned on row by row, the afterimage acquisition circuit reads the afterimage signals of the detection pixel units row by row, and sends the afterimage signals of each row of detection pixel units to the system circuit in real time; through this step, the deep cleaning of the afterimage signals of the detection pixel units can be realized, and the interference to the acquisition of the next image signal can be avoided;

[0116] The system circuit judges whether the difference between the afterimage signal of the current row of detection pixel units minus the afterimage signal of the previous row of detection pixel units is less than the second threshold, and when it is determined that it is less than the second threshold, sends a second control signal to the reading circuit;

[0117] The reading circuit stops reading the image signals of the detection pixel units under the action of the second control signal, so that the reading circuit only works during the image acquisition process, thereby ensuring the image acquisition quality and being beneficial to the doctor's diagnosis of the condition.

[0118] In some embodiments, in the above driving method provided by the embodiments of the present invention, while the system circuit sends the first control signal to the reading circuit, the following steps can also be performed:

[0119] The system circuit sends instructions to the gate driving circuit and the afterimage acquisition circuit to start working simultaneously with the reading circuit, so as to realize that after the image signals of a row of detection pixel units are acquired, the afterimage signals of this row of detection pixel units can be exported in time, avoiding affecting the acquisition of the next image signal.

[0120] In some embodiments, in the above driving method provided by the embodiments of the present invention, the system circuit sends the first control signal to the reading circuit, which specifically may include:

[0121] The system circuit sends a first control signal to the reading circuit to start working after a preset time, and the preset time is the integration time set for image acquisition, so that each detection pixel unit can be read by the reading circuit after completely converting the optical signal into an electrical signal, thereby effectively ensuring the intensity of the image signal.

[0122] For a better understanding of the above driving method provided by the embodiments of the present invention, the following Figure 7 specifically describes the above driving method provided by the embodiments of the present invention.

[0123] First step, when the system is powered on, the gate drive circuit and the ghost image acquisition circuit start working simultaneously. The nth gate line Gate n is at a high level, which can turn on the second transistor T2 of the (n - 1)th row detection pixel unit. At this time, X-Ray is not exposed, and the ghost image acquisition circuit acquires the first ghost image signal A and transmits it to the system circuit;

[0124] Second step, when the ray generator is controlled by the handle to emit X-Ray and starts exposure, the (n + 1)th gate line Gate n + 1 is at a high level, turning on the second transistor T2 of the nth row detection pixel unit. The ghost image acquisition circuit acquires the second ghost image signal B after exposure and transmits it to the system circuit. The system circuit determines whether the difference B - A between the second ghost image signal B and the first ghost image signal A is greater than the first threshold;

[0125] Third step, when the system circuit determines that the difference B - A between the second ghost image signal B and the first ghost image signal A is greater than the first threshold, the system circuit sends an instruction to the gate drive circuit, the ghost image acquisition circuit, and the reading circuit to start working after t seconds. t is the integration time set for image acquisition, and t needs to be greater than the exposure time of X-Ray, which is 0.5s;

[0126] Fourth step, after image acquisition starts, when the (n + 1)th gate line Gate n + 1 is at a high level, the first transistor T1 of the (n + 1)th row detection pixel unit and the second transistor T2 of the nth row detection pixel unit can be turned on simultaneously. While the reading circuit acquires the image signal of the (n + 1)th row detection pixel unit, the ghost image acquisition circuit clears the ghost image signal of the nth row detection pixel unit;

[0127] The specific process of residual charge clearing is as follows: after the second transistor T2 is turned on, Vo rises to a high level to apply a greater reverse bias voltage to the photodiode PD for deep clearing of residual charges. Before the second transistor T2 is turned off, Vo returns to a low level (this low level can be the same as the reference signal Ref of the reading circuit), restoring the level at the connection point of the photodiode PD and the first transistor T1 to avoid interference with the acquisition of the next image signal;

[0128] Fifth step, when all image signals are acquired, the ghost image signals acquired by the ghost image acquisition circuit will become smaller accordingly. After the system circuit receives the ghost image signals of two consecutive rows, it determines whether the difference between the ghost image signal of the latter row minus the ghost image signal of the former row is less than the second threshold. When it is determined that it is less than the second threshold, an instruction to stop image acquisition is sent to the reading circuit to end image acquisition. In some embodiments, the absolute value of the second threshold can be equal to the first threshold.

[0129] Sixth step, process all image signals and form an image.

[0130] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A flat panel detector, characterized in that, it includes: a plurality of detection pixel units arranged in an array, a gate driving circuit, a residual image acquisition circuit, a system circuit, and a reading circuit; wherein, the gate driving circuit is electrically connected to each row of the detection pixel units respectively; the residual image acquisition circuit is electrically connected to each row of the detection pixel units respectively, and the residual image acquisition circuit is configured to read the residual image signals of the detection pixel units; the system circuit is electrically connected to the residual image acquisition circuit and the reading circuit respectively, and the system circuit is configured to control whether the reading circuit reads the image signals of the detection pixel units according to the residual image signals of the detection pixel units; the residual image acquisition circuit is specifically configured to read the residual image signals of the detection pixel units row by row; the system circuit is specifically configured to judge whether the difference between the residual image signal of the detection pixel units in the current row minus the residual image signal of the detection pixel units in the previous row is greater than a first threshold or less than a second threshold, and when it is determined to be greater than the first threshold, send a first control signal to the reading circuit, and when it is determined to be less than the second threshold, send a second control signal to the reading circuit; the reading circuit is specifically configured to read the image signals of the detection pixel units under the action of the first control signal, and stop reading the image signals of the detection pixel units under the action of the second control signal.

2. The flat panel detector according to claim 1, characterized in that, it further includes a plurality of gate lines and a plurality of reading lines arranged crosswise, and the plurality of reading lines include a plurality of first reading lines and a plurality of second reading lines; the detection pixel unit includes: a first transistor, a second transistor, and a photodiode; in the detection pixel unit, the first pole of the first transistor, the first pole of the second transistor, and the first electrode of the photodiode are electrically connected, and a negative level is applied to the second electrode of the photodiode; the gates of all the first transistors in the detection pixel units of the same row are electrically connected to the gate driving circuit through one of the gate lines, and the second poles of all the first transistors in the detection pixel units of the same column are electrically connected to the reading circuit through one of the second reading lines; the gates of all the second transistors in the detection pixel units of the same row are electrically connected to the gate driving circuit through one of the gate lines, and in adjacent rows, the gates of all the second transistors in the detection pixel units of the upper row and the gates of all the first transistors in the detection pixel units of the lower row share one of the gate lines; the second poles of all the second transistors in the detection pixel units of the same column are electrically connected to the residual image acquisition circuit through one of the first reading lines.

3. The flat panel detector according to claim 1, characterized in that, the residual image acquisition circuit includes: a first amplifier, a first integration capacitor, a first capacitor, a second capacitor, a third capacitor, a first switch, a second switch, a third switch, a fourth switch, a resistor, a data selector, an analog-to-digital converter, and a data interface; The inverting input terminal of the first amplifier is connected to the detection pixel unit, and the frequency conversion signal is loaded at the non-inverting input terminal of the first amplifier; The first integrating capacitor is connected between the inverting input terminal and the output terminal of the first amplifier; The first switch is arranged in parallel with the first integrating capacitor; The second switch is in parallel with the resistor; The third switch is connected in series between the first end of the resistor and the first pole of the first capacitor; The fourth switch is connected in series between the first end of the resistor and the first pole of the second capacitor; The second end of the resistor is electrically connected to the output terminal of the first amplifier; The first pole of the first capacitor is electrically connected to the first input terminal of the data selector; The first pole of the second capacitor is electrically connected to the second input terminal of the data selector; The second poles of the first capacitor, the second capacitor, and the third capacitor are grounded; The output terminal of the data selector is electrically connected to the first input terminal of the analog-to-digital converter, the output terminal of the analog-to-digital converter is electrically connected to the input terminal of the data interface, and a fixed positive level is loaded at the second input terminal of the analog-to-digital converter and the first pole of the third capacitor; The output terminal of the data interface is electrically connected to the system circuit.

4. The flat panel detector according to claim 1, characterized in that, the reading circuit includes a plurality of sub-circuits, and each of the sub-circuits is electrically connected to a column of the detection pixel units; the sub-circuit includes a second amplifier, a second integrating capacitor, and a fifth switch. Among them, the inverting input terminal of the second amplifier is connected to the detection pixel unit, the reference signal is loaded at the non-inverting input terminal of the second amplifier, the second integrating capacitor is connected between the inverting input terminal and the output terminal of the second amplifier, and the fifth switch is arranged in parallel with the second integrating capacitor.

5. A radiographic imaging device, characterized in that, comprising: a handle, a ray generator, a host computer, and the flat panel detector according to any one of claims 1-4; wherein, the handle is electrically connected to the ray generator through a communication wire, the flat panel detector is independently arranged with respect to the handle and the ray generator, and the flat panel detector communicates with the host computer in a wireless or wired manner.

6. A driving method for the radiographic imaging device according to claim 5, characterized in that, comprising: the gate driving circuit drives the detection pixel unit to open, the afterimage acquisition circuit reads the afterimage signal of the detection pixel unit, and sends the afterimage signal of the detection pixel unit to the system circuit in real time; using the handle to control the ray generator to emit rays; the system circuit controls whether the reading circuit reads the image signal of the detection pixel unit according to the afterimage signal of the detection pixel unit; the host computer processes and forms an image of the image signal of the detection pixel unit read by the reading circuit; The afterimage acquisition circuit reads the afterimage signal of the detection pixel unit, specifically including: the afterimage acquisition circuit reads the afterimage signal of the detection pixel unit row by row; The system circuit controls whether the reading circuit reads the image signal of the detection pixel unit according to the afterimage signal of the detection pixel unit, specifically including: The system circuit determines whether the difference between the afterimage signal of the detection pixel unit in the current row minus the afterimage signal of the detection pixel unit in the previous row is greater than a first threshold, and when it is determined to be greater than the first threshold, sends a first control signal to the reading circuit; Under the action of the first control signal, the reading circuit reads the image signals of the detection pixel units row by row and sends the read image signals of the detection pixel units to the host computer.

7. The driving method according to claim 6, wherein, While the reading circuit reads the image signals of the detection pixel units row by row under the action of the first control signal, it further includes: The gate driving circuit drives the detection pixel units to be turned on row by row, the afterimage acquisition circuit reads the afterimage signals of the detection pixel units row by row, and sends the afterimage signals of the detection pixel units in each row to the system circuit in real time; The system circuit determines whether the difference between the afterimage signal of the detection pixel unit in the current row minus the afterimage signal of the detection pixel unit in the previous row is less than a second threshold, and when it is determined to be less than the second threshold, sends a second control signal to the reading circuit; Under the action of the second control signal, the reading circuit stops reading the image signals of the detection pixel units.

8. The driving method according to claim 7, wherein, While the system circuit sends the first control signal to the reading circuit, it further includes: The system circuit sends instructions to the gate driving circuit and the afterimage acquisition circuit to start working simultaneously with the reading circuit.

9. The driving method according to claim 8, wherein, The system circuit sends the first control signal to the reading circuit, specifically including: The system circuit sends a first control signal to the reading circuit to start working after a preset time, and the preset time is the integration time set for image acquisition.

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