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 X-ray detectors. [Background technology]

[0002] X-ray imaging devices, which use X-rays to obtain images of the inside of an object, are used in a variety of fields, including medicine and industry. X-ray imaging devices include an X-ray source that generates X-rays and an X-ray detector that detects the X-rays that pass through the object.

[0003] An X-ray detector detects X-rays that pass through an object on a pixel-by-pixel basis and generates an electrical signal corresponding to the magnitude of the detected X-rays. For example, an X-ray detector may include a charge generation layer that generates charges corresponding to the magnitude of the detected X-rays, and a TFT array layer containing multiple thin film transistors (TFTs) arranged in a matrix to generate an electrical signal corresponding to the magnitude of the generated charges. The TFT array layer requires a gate circuit to input gate signals to drive each TFT and a readout circuit to output readout signals. The gate circuit receives drive signals from a controller, generates gate signals to drive each TFT, and applies them to each TFT. Such gate circuits can be implemented in the form of a gate board or a gate chip-on-film (COF). Gate boards are large, making them difficult to design for miniaturization. In particular, the use of gate boards poses a challenge in implementing flexible detectors. To solve this problem, a technology has been introduced in which the gate board is replaced with a gate chip-on-film and a gate-connected flexible printed circuit board (FPCB) that is circuit-connected to the gate chip-on-film.

[0004] The gate-connected FPCB receives a driving signal from an external driving circuit and transmits it to the gate chip-on-film. The gate chip-on-film generates a gate signal based on the driving signal from the gate-connected FPCB and applies it to each TFT. The gate-connected FPCB must be relatively longer than the gate chip-on-film to connect to the external driving circuit. It also has a relatively long length because it must include a connector for circuit connection with the external driving circuit. Because the readout circuit, e.g., the leadout chip-on-film, is formed along one side of the TFT detector, and the gate chip-on-film and gate-connected FPCB are both formed along the other side of the TFT detector, the length of the TFT detector increases in the direction in which the gate chip-on-film and gate-connected FPCB are formed, making a miniaturized design difficult. Furthermore, because the gate-connected FPCB is formed together with the relatively compact gate chip-on-film, the potential for miniaturization achieved by using a compact gate chip-on-film is negated. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Registered Patent Publication No. 10-1139408 (Publication date: April 27, 2012) Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the present invention is to provide an X-ray detector that can be designed to be miniaturized by optimizing the connector structure of a thin film transistor and can perform imaging by effectively contacting an object such as a pipe. [Means for solving the problem]

[0007] An X-ray detector for detecting X-rays and generating a corresponding output signal according to an embodiment of the present invention includes a TFT array including a plurality of pixel TFT circuits each generating the output signal according to the intensity of the detected X-rays, a gate circuit configured to apply gate signals for driving the plurality of pixel TFT circuits to the TFT array, and a readout circuit configured to receive the output signals generated by the plurality of pixel TFT circuits and transmit them 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 circuitry 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.

[0008] The gate-coupled FPCB may be disposed along the same side of 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-coupled FPCB and the readout circuit may be arranged together along an adjacent side of the X-ray detector to which the gate chip-on-film is arranged.

[0010] The readout circuit may comprise a leadout chip on film.

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

[0012] An X-ray detector according to an embodiment of the present invention includes a TFT array including a plurality of pixel TFT circuits, each generating an output signal according to 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 an external device. The gate circuit includes a gate connection circuit that receives a drive signal from an external device, and a gate signal generation circuit that receives the drive signal from the gate connection circuit and generates the gate signal. The TFT array is configured to form a rectangular region. The gate connection circuit and the readout circuit are arranged along one side of the rectangular region of the TFT array, and the gate signal generation circuit is arranged along a side adjacent to the side of the rectangular region on which the gate connection circuit and the readout circuit are arranged.

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

[0014] According to the present invention, the gate-connected FPCB is spatially separated from the gate chip-on-film and arranged along the same side of the TFT X-ray detector together with the readout chip-on-film, thereby enabling components to be arranged without interference when designing a printed circuit board, and enabling the design of a miniaturized X-ray detector.

[0015] In addition, by spatially separating the relatively long gate-connected FPCB from the relatively short gate chip-on-film and positioning it along the other side, the length of the portion extending from the TFT X-ray detector to the outside in the direction in which the gate chip-on-film is formed can be minimized, thereby allowing the TFT X-ray detector to be placed in maximum contact with an object such as a pipe, enabling effective imaging. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a cross-sectional view schematically illustrating a direct type X-ray detector according to an embodiment of the present invention. [Figure 2] FIG. 10 is a cross-sectional view schematically illustrating an indirect type X-ray detector according to another embodiment of the present invention. [Figure 3] 1 is a diagram schematically illustrating an X-ray detector according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily understand and practice the present invention. However, the present invention may be embodied in many different forms and is not limited to the described embodiments.

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

[0019] 1, an X-ray detector 10 according to an embodiment of the present invention may be a direct-type digital X-ray detector that directly converts X-ray photons into electric charges. Also, the X-ray detector 10 according to an embodiment of the present invention may be a bendable flexible X-ray detector.

[0020] 1, in an X-ray detector 10 according to an embodiment of the present invention, a TFT array 13, a charge collector 15, a photoconductor layer 17, and an upper electrode 19 may be sequentially formed on a flexible substrate 11. For example, the substrate 11 may be made of a flexible synthetic resin material, and thus the X-ray detector 10 according to an embodiment of the present invention may be implemented as a flexible detector.

[0021] When X-rays are incident while a high voltage from a power source 21 is applied to the upper electrode 19, the photoconductor layer 17 generates charges. The photoconductor layer 17 may be made of a material that directly converts X-ray photons into charges, i.e., a photoconductor, such as amorphous selenium, lead oxide (PbO), thallium bromide (HgI2), etc. In this case, an electrical insulating layer 18 may be formed between the upper electrode 19 and the photoconductor layer 17, electrically insulating the upper electrode 19 and the photoconductor layer 17 from each other.

[0022] The TFT array 13 includes a plurality of pixel TFT circuits 23 and may be implemented in the form of a flexible panel. As is well known, the plurality of pixel TFT circuits 23 may be arranged in a matrix on a pixel-by-pixel basis, thereby allowing the TFT array 13 to form a rectangular area. 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, with the source terminal S connected to the storage capacitor 231. The gate terminal G is signal-connected to a gate circuit, i.e., a gate chip-on-film (COF) 311, via a gate line 235, and the data terminal D is signal-connected to a readout circuit, i.e., a readout IC chip-on-film 33, via a data line 237.

[0023] When charges are generated in the photoconductive layer 17 due to the incidence of X-rays, positive charges among the generated charges are collected by the charge collector 15. The positive charges collected in the charge collector 15 are then stored in the storage capacitor 231 of the pixel TFT circuit 23. In this process, the amount of charge generated by the photoconductive layer 17 varies depending on the intensity of the incident X-rays, and as a result, the amount of charge stored in the storage capacitor 231 varies depending on the intensity of the X-rays. When a gate signal, i.e., a scan signal, is applied to the gate terminal G through the gate line 235, the TFT switching element 233 is turned on, and an output signal corresponding to the amount of charge stored in the storage capacitor 231 is output to the data line 237 through the data terminal D. In this manner, an output signal corresponding to the intensity of the X-rays detected for each pixel is output, and this output signal can be used to generate an X-ray image. Meanwhile, although not shown in the drawing, as is well known, a circuit element, e.g., a switching element, for initializing the storage capacitor 231 after outputting an output signal by turning on the TFT switching element 233 may be connected in parallel to the storage capacitor 231.

[0024] 2, an X-ray detector 10 according to another embodiment of the present invention may be an indirect-type digital X-ray detector that converts X-rays into visible light and then converts the visible light photons into electric charges. The same reference numerals are used to designate the same parts as those in the direct-type X-ray detector described above with reference to FIG. 1, and redundant descriptions will be omitted.

[0025] 2, the indirect type X-ray detector 10 includes a scintillator layer 37 that converts incident X-rays into visible light, and a photodiode layer 35 that generates charges in response to 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 that converts the visible light emitted from the scintillator layer 37 into charges. As in the previous embodiment, the charges generated in the photodiode layer 35 are detected by the TFT array 13.

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

[0027] 3 shows an exemplary plan view of the TFT array 13 of the X-ray detector 10, which may be configured to have an overall rectangular shape. As described 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 the gate line 235 connected to the pixel TFT circuit 23. According to an embodiment of the present invention, the gate circuit 31 is divided into two parts, namely, a gate chip-on-film (gate COF) 311 and a gate-connecting FPCB (flexible printed circuit board) 313, and the gate chip-on-film 311 and the gate-connecting FPCB 313 are respectively arranged along different sides 101 and 102 of the X-ray detector 10. Here, the sides of the X-ray detector 10 may be understood as sides of the rectangular region of the TFT array 13. The gate-connecting FPCB 313 is signal-connected to an external controller through a connector 314, receives a driving signal from the controller, and transmits it to the gate chip-on-film 311. The gate chip-on-film 311 generates a gate signal according to the received driving signal and applies it to the gate line 235.

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

[0030] According to an embodiment of the present invention, the readout COF 33 may 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 may be arranged along one side 101 of the rectangular X-ray detector 10, and the gate-connected FPCB 313 of the gate circuit 31 and the readout COF 33 may be arranged along a side 102 adjacent to the side 101 of the X-ray detector 10 on which the gate chip-on-film 311 is arranged. According to an embodiment of the present invention, in consideration of the fact that the gate-connected FPCB 313 and the readout COF 33 must be formed relatively long and must be provided with connectors 314 and 331 for connection in order to be connected to an external controller or video signal processor, the gate-connected FPCB 313 and the readout COF 33 are arranged on the same side 102, thereby significantly reducing the size of the X-ray detector 10 in the height direction, i.e., the vertical direction in FIG. 3 . As a result, the gate chip-on-film 311 forms a portion of the X-ray detector 10 that protrudes outward from the TFT array 13 in the height direction, thereby 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 closely in the height direction, and imaging can be performed with the X-ray detector 10 positioned very close to the connecting portion of a T-shaped pipe. In addition, the gate chip-on-film 311 and the gate connecting FPCB 313 are arranged along different sides of the X-ray detector, preventing them from interfering with each other.

[0031] Although a direct type X-ray detector has been described above as an example, it should be understood that the present invention can also be applied to an indirect type X-ray detector having a TFT array. Furthermore, as described 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 may be a rigid X-ray detector in which TFTs are formed on a glass substrate.

[0032] Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these examples, and various modifications made by those skilled in the art using the basic concept of the present invention 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 collector 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 circuit 33: Readout circuit 311: Gate chip on film 313: Gate-connected FPCB 314: Connector 331: Connector 101, 102: X-ray detector edges

Claims

1. 1. An X-ray detector for sensing X-rays and generating a corresponding output signal, a TFT array including a plurality of pixel TFT circuits each generating the output signal according to the intensity of the sensed X-ray; a gating circuit configured to apply a gating signal to the TFT array to drive the plurality of pixel TFT circuits; and a readout circuit configured to receive the output signals generated by the plurality of pixel TFT circuits and transmit the output signals to an external device; The gate circuit a gate chip-on-film configured to generate and apply the gate signal to the TFT array; and a gate-connected FPCB circuitry connected to the gate chip-on-film so as to receive a driving signal for generating the gate signal and transmit the driving signal 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, respectively.

2. 2. The X-ray detector of claim 1, wherein the gate-coupled FPCB is disposed along the same side of the X-ray detector as the readout circuit.

3. the gate chip-on-film is disposed along one side of the X-ray detector; 3. The X-ray detector of claim 2, wherein the gate-connected FPCB and the readout circuit are co-located along sides adjacent to one side of the X-ray detector on which the gate chip-on-film is located.

4. 4. The x-ray detector of claim 3, wherein the readout circuit comprises a readout chip on film.

5. 10. The X-ray detector of claim 1, wherein the X-ray detector comprises a bendable flexible detector.

6. a TFT array including a plurality of pixel TFT circuits each generating an output signal according to the intensity of a sensed X-ray; a gating circuit configured to apply a gating signal to the TFT array for driving the pixel TFT circuit; and a readout circuit configured to read out the output signal and transmit it to an external device; the gate circuit includes a gate connection circuit that receives a driving signal from an external device, and a gate signal generation circuit that receives the driving signal from the gate connection circuit and generates the gate signal; the TFT array is configured to form a rectangular area; the gate coupling circuit and the readout circuit are disposed together along one side of the rectangular region of the TFT array; The gate signal generating circuit is arranged along a side adjacent to one side of the rectangular region in which the gate coupling circuit and the readout circuit are arranged.

7. The gate connection circuit is configured in the form of a FPBC, 7. The X-ray detector according to claim 6, wherein the readout circuit and the gate signal generating circuit are each configured in the form of a chip-on-film.

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