X-ray detector

Abstract

The X-ray detector detects X-rays and generates corresponding output signals. The X-ray detector includes a TFT array including a plurality of pixel TFT circuits that generate the output signals according to the intensities of the detected X-rays, a gate circuit configured to apply gate signals for driving the pixel TFT circuits to the TFT array, and a readout circuit configured to receive the output signals generated by the pixel TFT circuits and transmit them to the outside. The gate circuit includes a gate chip-on-film configured to generate the gate signals and apply them to the TFT array, and a gate-connected FPCB circuitry connected to the gate chip-on-film so as to receive drive signals for generating the gate signals and transmit them to the gate chip-on-film. The gate chip-on-film and the gate-connected FPCB are disposed along different sides of the X-ray detector.

Description

Technical Field

[0001] The present invention relates to an X-ray detector.

Background Art

[0002] X-ray imaging devices that acquire internal images of an object using X-rays are used in various fields such as the medical field and the industrial field. An X-ray imaging device includes an X-ray source that generates X-rays and an X-ray detector that detects the X-rays that have passed through the object.

[0003] The X-ray detector detects X-rays that have passed through the object in pixel units and generates an electrical signal based on the magnitude of the detected X-rays. For example, the X-ray detector includes a charge generation layer that generates charge based on the magnitude of the detected X-rays, and a TFT array layer that includes a plurality of thin film transistors (TFTs) arranged in a matrix form for generating an electrical signal based on the magnitude of the generated charge. On the other hand, the TFT array layer requires a gate circuit for inputting a gate signal for driving each TFT and a readout circuit for outputting a readout signal that is an output signal. The gate circuit receives an input of a driving signal from a controller and is configured to generate a gate signal for driving each TFT and apply it to each TFT. Such a gate circuit can be embodied in the form of a gate board or in the form of a gate chip on film (gate COF). Since the gate board is large, it is difficult to realize a miniaturized design. In particular, when a gate board is applied, there is a problem that it cannot be embodied in the form of a flexible detector. To solve such a problem, a technique of replacing the gate board with a gate chip on film and a gate connection FPCB (flexible printed circuit board) circuitally connected thereto has been introduced.

[0004] The gate-coupled FPCB receives a drive signal from an external drive circuit and transmits it to the gate chip-on-film. The gate chip-on-film generates a gate signal based on the drive signal transmitted from the gate-coupled FPCB and applies it to each TFT. At this time, the gate-coupled FPCB must be formed to be relatively longer than the gate chip-on-film in order to connect to the external drive circuit, and it must also be equipped with a connector for circuit connection to the external drive circuit, thus having a relatively long length. Since the readout circuit, for example, the readout chip-on-film, is formed along one side of the TFT detector, and the gate chip-on-film and gate-coupled FPCB are formed together along the other side of the TFT detector, the length of the TFT detector in the direction in which the gate chip-on-film and gate-coupled FPCB are formed becomes large, making miniaturization difficult. Furthermore, since the gate-coupled FPCB is formed together with the relatively compact gate chip-on-film, the possibility of miniaturization through the application of a compact gate chip-on-film is offset. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Registered Patent Publication No. 10-1139408 (Publication Date: 2012.04.27.) [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The problem that this invention aims to solve is to provide an X-ray detector that can perform imaging by optimizing the connector structure of a thin-film transistor to enable miniaturization, and by making it possible to make close contact with an object such as a pipe. [Means for solving the problem]

[0007] An X-ray detector according to an embodiment of the present invention, which senses X-rays and generates a corresponding output signal, includes a TFT array containing a plurality of pixel TFT circuits that each generate the output signal according to the intensity of the sensed X-rays, a gate circuit configured to apply a gate signal to the TFT array for driving the plurality of pixel TFT circuits, and a readout circuit configured to receive and transmit the output signal generated by the plurality of pixel TFT circuits to the outside. The gate circuit includes a gate chip-on film configured to generate the gate signal and apply it to the TFT array, and a gate-connected FPCB that is circuit-connected to the gate chip-on film so as to receive and transmit a drive signal for generating the gate signal to the gate chip-on film. The gate chip-on film and the gate-connected FPCB are arranged along different sides of the X-ray detector, respectively.

[0008] The gate-coupled FPCB may be arranged along the same side as the readout circuit and the X-ray detector.

[0009] The gate chip-on film may be arranged along one side of the X-ray detector, and the gate-connecting FPCB and the readout circuit may be arranged together along adjacent sides of the side of the X-ray detector where the gate chip-on film is arranged.

[0010] The aforementioned readout circuit may consist of a readout chip-on film.

[0011] The aforementioned X-ray detector may consist of a flexible detector that can be bent.

[0012] An X-ray detector according to an embodiment of the present invention includes a TFT array containing a plurality of pixel TFT circuits that each generate an output signal based on the intensity of detected X-rays, a gate circuit configured to apply a gate signal to the TFT array for driving the pixel TFT circuits, and a readout circuit configured to read out the output signal and transmit it to the outside. The gate circuit includes a gate coupling circuit that receives a drive signal from the outside, and a gate signal generation circuit that receives the drive signal from the gate coupling circuit and generates the gate signal. The TFT array is configured to form a rectangular region. The gate coupling circuit and the readout circuit are arranged together along one side of the rectangular region of the TFT array, and the gate signal generation circuit is arranged along adjacent sides of the side of the rectangular region where the gate coupling circuit and the readout circuit are arranged.

[0013] The gate coupling circuit may be configured in the form of an FPBC, and the readout circuit and the gate signal generation circuit may each be configured in the form of a chip-on-film. [Effects of the Invention]

[0014] According to the present invention, by spatially separating the gate-linked FPCB from the gate chip-on-film and arranging it together with the readout chip-on-film along the same side of the TFT X-ray detector, it is possible to arrange components without interference during the design of the printed circuit board, and to design a smaller X-ray detector.

[0015] Furthermore, by spatially separating the relatively long gate-linked FPCB from the relatively short gate-tip-on-film and positioning it along the other side, the length of the portion leading out from the TFT X-ray detector in the direction in which the gate-tip-on-film is formed can be minimized. This allows the TFT X-ray detector to be in maximum contact with the object, such as a pipe, enabling effective imaging. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic cross-sectional view of a direct-type X-ray detector according to one embodiment of the present invention. [Figure 2] This is a schematic cross-sectional view of an indirect X-ray detector according to another embodiment of the present invention. [Figure 3] This is a schematic diagram showing an X-ray detector according to an embodiment of the present invention. [Modes for carrying out the invention]

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings, so that those with ordinary skill in the art to which the present invention pertains can easily implement it. However, the present invention can be embodied in a variety of different forms and is not limited to the embodiments described.

[0018] The X-ray detector according to the embodiment of the present invention may be a direct conversion or an indirect conversion X-ray detector. Figure 1 illustrates an example of a direct conversion X-ray detector, and Figure 2 illustrates an example of an indirect conversion X-ray detector.

[0019] Referring to Figure 1, the X-ray detector 10 according to one embodiment of the present invention may be a direct-type digital X-ray detector that directly converts X-ray photons into electric charge. Furthermore, the X-ray detector 10 according to an embodiment of the present invention may be a flexible X-ray detector that can be bent.

[0020] Referring to Figure 1, according to the X-ray detector 10 of the embodiment of the present invention, a TFT array 13, a charge collection unit 15, a photoconductor layer 17, and an upper electrode 19 can be sequentially formed on a bendable substrate 11. For example, the substrate 11 may be made of a bendable synthetic resin material, thereby enabling the X-ray detector 10 of the embodiment of the present invention to be realized as a flexible detector.

[0021] When X-rays are incident while a high voltage of the power supply 21 is applied to the upper electrode 19, the photoconductive layer 17 generates charges. The photoconductive layer 17 can be formed of a material that directly converts X-ray photons into charges, such as amorphous selenium, lead oxide (PbO), thallium bromide (HgI2), etc., that is, a photoconductor. At this time, an electric insulating layer 18 is formed between the upper electrode 19 and the photoconductive layer 17 so that the upper electrode 19 and the photoconductive layer 17 can be electrically insulated from each other.

[0022] The TFT array 13 includes a plurality of pixel TFT circuits 23 and can be embodied in the form of a flexible panel. As is well known, the plurality of pixel TFT circuits 23 can be arranged in a matrix form in pixel units, whereby the TFT array 13 can form a rectangular region. Each pixel TFT circuit 23 includes a storage capacitor 231 and a TFT switching element 233. The TFT switching element 233 includes a gate terminal G, a data terminal D, and a source terminal S, and the source terminal S is connected to the storage capacitor 231. The gate terminal G is signal-connected to a gate circuit, that is, a gate chip on film (COF) 311 through a gate line 235, and the data terminal D is signal-connected to a readout circuit, that is, a readout IC chip on film 33 through a data line 237.

[0023] When charges are generated in the photoconductive layer 17 by the incidence of X-rays, the positive charges among the generated charges are collected by the charge collection portion 15. Further, the positive charges collected in the charge collection portion 15 are stored in the storage capacitor 231 of the pixel TFT circuit 23. In this process, since the amount of charges generated by the photoconductive layer 17 varies depending on the intensity of the incident X-rays, as a result, the amount of charges stored in the storage capacitor 231 varies depending on the intensity of the X-rays. When a gate signal, that is, a scan signal, is applied to the gate terminal G through the gate line 235, the TFT switching element 233 is turned on, and thereby an output signal corresponding to the amount of charges stored in the storage capacitor 231 is output to the data line 237 through the data terminal D. Output signals corresponding to the intensity of the X-rays detected for each pixel are output in such a manner, and these output signals can be used for the generation of an X-ray image. On the other hand, although not shown in the drawings, as is well known, a circuit element for initializing the storage capacitor 231, for example, a switching element, can be connected in parallel to the storage capacitor 231 after the output signal is output by turning on the TFT switching element 233.

[0024] On the other hand, referring to FIG. 2, the X-ray detector 10 according to another embodiment of the present invention can be an indirect digital X-ray detector that converts X-rays into visible light and then changes the photons of the visible light into charges. The same drawing numbers are assigned to the same parts as those of the direct X-ray detector described with reference to FIG. 1 above, and redundant descriptions are omitted.

[0025] Referring to Figure 2, the indirect X-ray detector 10 includes a scintillator layer 37 that converts incident X-rays into visible light, and a photodiode layer 35 that generates an electric charge in the visible light converted by the scintillator layer 37. The scintillator layer 37 may be formed of a scintillator that emits visible light proportional to the incident X-rays. The photodiode layer 35 may be formed of an amorphous silicon photodiode and converts the visible light emitted from the scintillator layer 37 into an electric charge. Similar to the embodiment described above, the charge generated in the photodiode layer 35 is detected by the TFT array 13.

[0026] The gate circuit 31 for applying a gate signal to the gate line 235 and the readout circuit 33 for receiving an output signal from the data line 237 and outputting it externally will be described below with reference to Figure 3.

[0027] Figure 3 illustrates an illustrative plan view of the TFT array 13 of the X-ray detector 10, and the TFT array 13 may be configured to have an overall rectangular shape. As mentioned above, the TFT array 13 includes a plurality of pixel TFT circuits 23 arranged in a matrix.

[0028] The gate circuit 31 is configured to apply a gate signal to a gate line 235 connected to the pixel TFT circuit 23. According to an embodiment of the present invention, the gate circuit 31 is composed of two parts, namely a gate chip-on-film (gate COF) 311 and a gate-connected FPCB (flexible printed circuit board) 313, and the gate chip-on-film 311 and the gate-connected FPCB 313 are arranged along different sides 101 and 102 of the X-ray detector 10, respectively. Here, the sides of the X-ray detector 10 may be understood as the sides of the rectangular region of the TFT array 13. The gate-connected FPCB 313 is signal-connected to an external controller via a connector 314 and receives a drive signal from the controller, which is transmitted to the gate chip-on-film 311. The gate chip-on-film 311 generates a gate signal from the received drive signal and applies it to the gate line 235.

[0029] The readout circuit 33 is implemented in chip-on-film form, and therefore the readout circuit 33 can be referred to as a readout COF. The readout COF 33 is connected to an external video signal processing unit via a connector 331 and is configured to transmit output signals to the video signal processing unit.

[0030] According to an embodiment of the present invention, the readout COF 33 can be arranged along one side of the X-ray detector 10. In this case, the gate chip-on-film 311 of the gate circuit 31 can be arranged along one side 101 of the rectangular X-ray detector 10, and the gate-connecting FPCB 313 and readout COF 33 of the gate circuit 31 can be arranged along the side 102 adjacent to the side 101 of the X-ray detector 10 where the gate chip-on-film 311 is located. According to an embodiment of the present invention, considering that the gate-connecting FPCB 313 and readout COF 33 must be formed to be relatively long in order to be signal-connected to an external controller or video signal processing unit, and must be equipped with connectors 314 and 331 for connection, the gate-connecting FPCB 313 and readout COF 33 can be arranged on the same side 102, thereby significantly reducing the size of the X-ray detector 10 in the height direction, or vertical direction in Figure 3. As a result, the gate chip-on film 311 forms a portion that protrudes outward from the TFT array 13 in the height direction of the X-ray detector 10, thus minimizing the height length of the portion that protrudes outward from the TFT array 13, which is the X-ray sensing area. This means that the X-ray detector 10 can approach the object very close in the height direction, thereby enabling imaging with the X-ray detector 10 positioned very close to the connection point of the T-shaped piping. In addition, interference between the gate chip-on film 311 and the gate connecting FPCB 313 can be prevented by arranging them along different sides of the X-ray detector.

[0031] Although a direct-type X-ray detector was described above as an example, it can be recognized that the present invention can also be applied to an indirect-type X-ray detector comprising a TFT array. Furthermore, as mentioned above, the X-ray detector according to the embodiment of the present invention may be embodied as a flexible detector that can be bent, or it may be an X-ray detector in the form of a rigid body with TFTs formed on a glass substrate.

[0032] Although embodiments of the present invention have been described above, the scope of the present invention is not limited thereto, and various modifications by those skilled in the art that utilize the basic concepts of the present invention as defined in the following claims also fall within the scope of the present invention. [Explanation of symbols]

[0033] 10: X-ray detector 11: Circuit board 13: TFT Array 15: Charge Collection Unit 17: Photoconductor layer 18: Electrical insulation layer 19: Upper electrode 21: Power supply 23: Pixel TFT Circuit 231: Storage Capacitor 233: TFT switching element G: Gate terminal S: Source terminal D: Data terminal 235: Gate Line 237: Data line 31: Gate Circuits 33: Lead-out circuit 311: Gate Chip-on Film 313: Gate-linked FPCB 314: Connector 331: Connector 101, 102: Edges of the X-ray detector

Claims

1. In an X-ray detector that detects X-rays and generates a corresponding output signal, A TFT array including a plurality of pixel TFT circuits that each generate the output signal based on the intensity of the detected X-rays, A gate circuit configured to apply a gate signal to the TFT array for driving the plurality of pixel TFT circuits, and The circuit includes a readout circuit configured to receive the output signal generated by the plurality of pixel TFT circuits and transmit it to the outside, The gate circuit is A gate chip-on film configured to generate the gate signal and apply it to the TFT array, and Includes a gate coupling FPCB that is circuit-connected to the gate chip-on-film so as to receive a drive signal for generating the gate signal and transmit it to the gate chip-on-film, The gate chip-on film and the gate-connecting FPCB are arranged along different sides of the rectangular X-ray detector, The gate-connected FPCB is arranged along the same side as the readout circuit and the X-ray detector, in an X-ray detector.

2. The gate chip-on film is positioned along one side of the X-ray detector. The X-ray detector according to claim 1, wherein the gate-connected FPCB and the readout circuit are arranged together along adjacent sides of one side of the X-ray detector on which the gate chip-on-film is located.

3. The X-ray detector according to claim 2, wherein the readout circuit comprises a readout chip-on film.

4. The X-ray detector according to claim 1, wherein the X-ray detector is composed of a flexible detector that can be bent.

5. A TFT array including multiple pixel TFT circuits that each generate an output signal based on the intensity of the detected X-rays, A gate circuit configured to apply a gate signal for driving the pixel TFT circuit to the TFT array, and Includes a readout circuit configured to read out the output signal and transmit it to the outside, The gate circuit includes a gate coupling circuit that receives a drive signal from an external source, and a gate signal generation circuit that receives the drive signal from the gate coupling circuit and generates the gate signal. The TFT array is configured to form a rectangular region. The gate coupling circuit and the readout circuit are arranged together along one side of the rectangular region of the TFT array. An X-ray detector in which the gate signal generation circuit is arranged along adjacent sides of one side of the rectangular region in which the gate coupling circuit and the readout circuit are located.

6. The gate coupling circuit is configured in the form of an FPCB. The X-ray detector according to claim 5, wherein the readout circuit and the gate signal generation circuit are each configured in the form of a chip-on-film.

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