Abstract:
An X-ray detector includes; a panel having a plurality of photo-detecting pixels generating electrical signals in response to the detection of X-rays, a gate driver providing a gate signal to the plurality of photo-detecting pixels, wherein the photo-detecting pixels output the electrical signals in response to the gate signal, a readout integrated circuit reading out the electrical signal in response to the gate signal, a main board including a controller receiving the electrical signal and converting the electrical signal to an image signal, a film attached to the panel and the main board, the film including a signal line electrically connecting the readout integrated circuit to the panel and main board, wherein the readout integrated circuit is mounted on the film, and a shielding layer covering the film and comprising a conductive material, wherein the shielding layer prevents externally applied electromagnetic signals from passing through the film.

Description:
[0001]    This application claims priority to Korean Patent application No. 2008-12632, filed on Feb. 12, 2008, and all the benefits accruing therefrom under 35 U.S.C. §119, the contents of which in its entirety are herein incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an X-ray detector. More particularly, the present invention relates to an X-ray detector capable of removing noise caused by electronic interference. 
         [0004]    2. Description of the Related Art 
         [0005]    In general, an X-ray detector is used in a medical diagnostic instrument to provide an X-ray image of a subject to a display apparatus by detecting the X-ray image produced by the absorption and transmission of X-rays through the subject. 
         [0006]    Presently, a flat panel X-ray detector employing digital radiography (“DR”), which does not require photographic film, is extensively used. The flat panel X-ray detector employing DR includes a plurality of photo-detecting pixels provided in a flat panel to detect X-rays generated by an X-ray generator. As used herein, X-rays, refer to electromagnetic radiation with a wavelength from about 0.01 nm to about 10 nm. Each photo-detecting pixel includes a photo diode that detects X-rays generated from the X-ray generator and outputs electric signals, and a switching device that switches the electric signals output from the photo diode. 
         [0007]    A readout integrated circuit and a gate driver are provided at an outer portion of the flat panel. The readout integrated circuit reads out the electric signals from the flat panel and the gate driver sequentially turns on switching devices aligned in a row direction to allow the readout integrated circuit to sequentially read out the electric signals from photo-detecting pixels aligned in the row direction. The electric signals output from the readout integrated circuit are processed through a controller provided in a main board, and then converted into image signals. The converted image signals are provided to a display apparatus to display X-ray images. 
         [0008]    In general, the readout integrated circuit is mounted on a film that connects the flat panel to the main board. The film is provided with a signal line that electrically connects the flat panel to the main board. However, the signals, which are input into or output from the readout integrated circuit, are distorted due to electronic interference generated from the main board or external electronic appliances. As a result, the display apparatus, which displays the image signals provided from the X-ray detector, displays images having noise, thereby deteriorating display quality of the X-ray image. 
       BRIEF SUMMARY OF THE INVENTION 
       [0009]    Therefore, the present invention provides an X-ray detector capable of removing noise caused by electronic interference. 
         [0010]    The present invention also provides a method of manufacturing the X-ray detector. 
         [0011]    In one exemplary embodiment, an X-ray detector includes; a panel comprising a plurality of photo-detecting pixels configured to generate electrical signals in response to the detection of X-rays, a gate driver configured to provide a gate signal to the plurality of photo-detecting pixels, wherein the photo-detecting pixels output the electrical signals in response to the gate signal, a readout integrated circuit configured to read out the electrical signal output from the photo-detecting pixels in response to the gate signal, a main board including a controller configured to receive the electrical signal from the readout integrated circuit and convert the electrical signal to an image signal, a film attached to the panel and the main board, the film including a signal line electrically connecting the readout integrated circuit to the panel and the main board, wherein the readout integrated circuit is mounted on the film; and a shielding layer covering the film and comprising a conductive material, wherein the shielding layer is configured to prevent externally applied electromagnetic signals from passing through the film. 
         [0012]    In another exemplary embodiment, a method of manufacturing an X-ray detector including a panel provided with photo-detecting pixels that detect an X-ray by converting the X-ray into an electrical signal, a readout integrated circuit that reads out the electrical signal output from the photo-detecting pixels, and a main board provided with a controller that receives the electrical signal from the readout integrated circuit to convert the electrical signal to an image signal, the method includes; providing a film, mounting the readout integrated circuit on the film, attaching the film to the panel and the main board to electrically connect the readout integrated circuit to the panel and the main board and disposing a shielding layer comprising a conductive material on the film, wherein the shielding layer is configured to protect signals passing through the film from external electronic interference. 
         [0013]    According to the above, the shielding layer is formed on the outer surface of the film onto which the readout integrated circuit is mounted, so that signals, which are input into or output from the readout integrated circuit, may be prevented from being distorted by external electronic interference. As a result, the display apparatus may display the X-ray image without forming a line-defect on the X-ray image. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The above and other advantages of the present invention will become readily apparent by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein: 
           [0015]      FIG. 1  is a top plan schematic view showing an exemplary embodiment of an X-ray detector according to the present invention; 
           [0016]      FIG. 2  is a cross-sectional view taken along line I-I′ shown in  FIG. 1 ; 
           [0017]      FIG. 3A  is a cross-sectional view showing an exemplary embodiment of the structure of a film illustrated in  FIG. 1 ; 
           [0018]      FIG. 3B  is a cross-sectional view showing another exemplary embodiment of the structure of the film according to the present invention; and 
           [0019]      FIG. 4  is a view showing an exemplary embodiment of an X-ray system having the exemplary embodiment of an X-ray detector illustrated in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    The invention now will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout. 
         [0021]    It will be understood that when an element is referred to as being “on” another element, it can be directly on the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
         [0022]    It will be understood that, although the terms first, second, third etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention. 
         [0023]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof. 
         [0024]    Furthermore, relative terms, such as “lower” or “bottom” and “upper” or “top,” may be used herein to describe one element&#39;s relationship to another elements as illustrated in the Figures. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. For example, if the device in one of the figures is turned over, elements described as being on the “lower” side of other elements would then be oriented on “upper” sides of the other elements. The exemplary term “lower”, can therefore, encompasses both an orientation of “lower” and “upper,” depending on the particular orientation of the figure. Similarly if the device in one of the figures is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements. The exemplary terms “below” or “beneath” can, therefore, encompass both an orientation of above and below. 
         [0025]    Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
         [0026]    Exemplary embodiments of the present invention are described herein with reference to cross section illustrations that are schematic illustrations of idealized embodiments of the present invention. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments of the present invention should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, a region illustrated or described as flat may, typically, have rough and/or nonlinear features. Moreover, sharp angles that are illustrated may be rounded. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the present invention. 
         [0027]    Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. 
         [0028]      FIG. 1  is a top plan schematic view showing an exemplary embodiment of an X-ray detector according to the present invention, and  FIG. 2  is a cross-sectional view taken along line I-I′ shown in  FIG. 1 . 
         [0029]    Referring to  FIG. 1 , the X-ray detector  100  includes a panel  110 , a gate driver  120 , a readout integrated circuit  130 , a main board  140  and a film  150 . The panel  110  includes a plurality of photo-detecting pixels, one exemplary embodiment of which is illustrated as photo-detecting pixel PP, each of which detects X-rays output from an X-ray generator (not shown) by converting the detected X-rays into the electric signals. In one exemplary embodiment, the photo-detecting pixels PP are aligned in the form of a matrix in the panel  110 . 
         [0030]    Each of the photo-detecting pixels PP includes a photodiode PD and a transistor Tr. The photodiode PD detects the X-rays generated from the X-ray generator and converts the X-rays into electric signals. A first electrode of the photodiode PD is connected to an input, or source, electrode of the transistor Tr, and a second electrode of the photodiode PD is connected to a bias line BL to which a bias voltage is applied. Meanwhile, a control, or gate, electrode of the transistor Tr is electrically connected to the gate driver  120  through a gate line GL, and an output, or drain, electrode of the transistor Tr is electrically connected to the readout integrated circuit  130  through a data line DL. 
         [0031]    As shown in  FIG. 2 , the panel  110  has a base substrate  111  on which the photo-detecting pixels PP are arranged. Although a plurality of photo-detecting pixels PP is formed on the base substrate  111 , only one photo-detecting pixel PP is shown in  FIG. 2 . 
         [0032]    Referring to  FIG. 2 , a control electrode  112   a  of the transistor Tr is formed on the base substrate  111 . In one exemplary embodiment, the control electrode  112   a  includes a metal layer substantially similar to that of the gate line GL (see,  FIG. 1 ). The control electrode  112   a  is covered with a gate insulating layer  113  on which an active layer  112   b  of the transistor Tr is formed. An input electrode  112   c  and an output electrode  112   d  of the transistor Tr are formed on the active layer  112   b.  The input electrode  112   c  is spaced apart from the output electrode  112   d  by a predetermined distance. 
         [0033]    In the present exemplary embodiment, the input electrode  112   c  of the transistor Tr is integrally formed with a first electrode  114   a  of the photodiode PD, so that they are electrically connected to each other. Alternative exemplary embodiments include configurations wherein the input electrode  112   c  and the first electrode  114   a  may be separately formed and then subsequently electrically connected. A silicon layer  114   b  is formed on the first electrode  114   a.  Although not shown in the  FIG. 2 , exemplary embodiments of the silicon layer  114   b  include configurations wherein the silicon layer  114   b  may have a stacked structure in which an n-type silicon layer, an intrinsic silicon layer and a p-type silicon layer are sequentially stacked. A second electrode  114   c  including a transparent conductive layer, exemplary embodiments of which include indium tin oxide (“ITO”) and indium zinc oxide (“IZO”), is formed on the silicon layer  114   b  while facing the first electrode  114   a.    
         [0034]    The photodiode PD and the transistor Tr having the above-mentioned structure are provided on the base substrate  111  and covered with a protective layer  115 . The protective layer  115  has a contact hole  115   a  through which the second electrode  114   c  of the photodiode PD is exposed. The bias line BL is electrically connected to the second electrode  114   c  of the photodiode PD through the contact hole  115   a.    
         [0035]    In addition, an insulating layer  116  is provided on the protective layer  115  to cover the bias line BL and to planarize a surface of the panel  110 . A scintillator  170  is provided on an upper surface of the panel  110 , that is, on the insulating layer  116 . The scintillator  170  receives X-rays from the X-ray generator and converts the X-ray into a light detectable by the photodiode PD. The photodiode PD detectable light is then output toward the panel  110 . In one exemplary embodiment the scintillator  170  may convert the X-rays into green light having a wavelength of 550 nm, i.e., light in the visible spectrum. In one exemplary embodiment, the scintillator  170  may include cesium iodide. 
         [0036]    Referring again to  FIG. 1 , the gate driver  120  provides gate signals to the photo-detecting pixels formed on the panel  110 . In detail, when the gate signal is applied to the gate line GL, the transistor Tr is turned on and the electric signal supplied from the photodiode PD is output through the output electrode  112   d  to the data line DL. The electric signal output from the output electrode  112   d  is provided to the readout integrated circuit  130  through the data line DL. In the present exemplary embodiment, the gate driver  120  is prepared in the form of an integrated circuit (“IC”) and is mounted on one side of the panel  110 . In another exemplary embodiment, the gate driver  120  may be integrally formed with the panel  110  through a thin film forming process. 
         [0037]    The readout integrated circuit  130  reads out the electric signal, which is output from the photo-detecting pixel PP that has been turned on in response to the gate signal. The main board  140  is provided with a control circuit (not shown) that receives the electric signal from the readout integrated circuit  130  to convert the electric signal to the image signal. The image signal generated from the control circuit is provided to a display apparatus (described in more detail with respect to  FIG. 4 ). Thus, the image photographed by the X-ray generator may be displayed on the display apparatus. The readout integrated circuit  130  is mounted on the film  150  and the film  150  is attached to the panel  110  and the main board  140 . 
         [0038]    As shown in  FIG. 2 , top and bottom surfaces of the film  150  are covered with shielding layers  160 . The shielding layers  160  may be applied after the readout integrated circuit  130  is mounted on the film  150 . The shielding layers  160  shield electronic interference provided to the film  150  from the exterior. In one exemplary embodiment of the present invention, the shielding layers  160  may be grounded. Exemplary embodiments also include configurations wherein the shielding layers  160  may include copper thin films. 
         [0039]      FIG. 3A  is a detailed cross-sectional view showing an exemplary embodiment of the structure of the film illustrated in  FIG. 1 . 
         [0040]    Referring to  FIG. 3A , the film  150  includes a first insulating layer  151 , a signal line  152  and a second insulating layer  153 . The signal line  152  is provided on the first insulating layer  151  to electrically connect the readout integrated circuit  130  to the data line DL provided on the panel  110  and the control circuit provided on the main board  140 . The second insulating layer  153  is aligned in opposition to the first insulating layer  151  to cover the signal line  152  provided on the first insulating layer  151 . 
         [0041]    Meanwhile, the shielding layers  160  cover the outer surfaces of the first and second insulating layers  151  and  153  in order to prevent the signals transferred through the signal line  152  from being distorted by the external electronic interference. Thus, if the film  150  is covered with the shielding layers  160 , the display apparatus may display the X-ray image based on the image signals provided from the X-ray detector  100  without deteriorating the display quality. 
         [0042]      FIG. 3B  is a cross-sectional view showing another exemplary embodiment of the film structure according to the present invention. Referring to  FIG. 3B , the film  150  according to another embodiment of the present invention includes a first insulating layer  151 , a signal line  152 , a second insulating layer  153 , a first ground interconnection  154 , a third insulating layer  155 , a second ground interconnection  156 , and a fourth insulating layer  157 . 
         [0043]    The first ground interconnection  154  is provided on an outer surface of the second insulating layer  153  and may be grounded. The first ground interconnection  154  is covered with the third insulating layer  155  facing the second insulating layer  153 . Meanwhile, the second ground interconnection  156  is formed on an outer surface of the first insulating layer  151  and may be grounded. The second ground interconnection  156  is covered with the fourth insulating layer  157  facing the first insulating layer  151 . 
         [0044]    Similar to the previous exemplary embodiment, shielding layers  160  are formed on outer surfaces of the third and fourth insulating layers  155  and  157  to shield electronic interference from the exterior. In one exemplary embodiment, the shielding layers  160  may be connected to the first or second ground interconnection  154  or  156 , so that the shielding layers  160  may be grounded. In one exemplary embodiment, the shielding layers  160  may be electrically connected to a ground terminal of the readout integrated circuit  130 . 
         [0045]      FIG. 4  is a view showing an exemplary embodiment of an X-ray system having the exemplary embodiment of an X-ray detector illustrated in  FIG. 1 . 
         [0046]    Referring to  FIG. 4 , the X-ray system  200  includes an X-ray generator  210  that generates X-rays  211  in a direction toward a predetermined region  51  of a patient  50  (that is, an inspection region), an X-ray detector  100  that detects X-rays  211  which have passed through the predetermined region  51  of the patient  50 , and a display apparatus  220  that displays an image by receiving image signals corresponding to the X-rays  211  detected by the X-ray detector  100 . Although the present exemplary embodiment of an X-ray system  200  is described with respect to the imaging of a patient  50 , it would be clear to one of ordinary skill in the art that such an exemplary embodiment of an X-ray system  200  may be applied to a wide range of applications wherein X-ray imaging is desired, e.g., luggage inspection, etc. 
         [0047]    In such an X-ray system  200 , if the X-ray is irradiated onto the predetermined region  51  of the patient  50 , the scintillator  170  provided between the panel  110  of the X-ray detector  100  and the patient  50  converts the X-ray  211 , which has passed through the patient  50 , into green light to provide the green light to the panel  110 . 
         [0048]    Since the X-ray detector  100  has been described in detail with reference to  FIGS. 1 and 2 , it will not be further described below. 
         [0049]    The X-ray detector  100  obtains image signals corresponding to X-rays  211 , which have passed through the patient  50 , and then provides the image signal to the display apparatus  220 . Accordingly, the display apparatus  220  may display the X-ray images corresponding to the image signals in real time. As an example of the present invention, the display apparatus  220  may include a liquid crystal display (“LCD”), and various other display types as would be known to one of ordinary skill in the art. 
         [0050]    Although the exemplary embodiments of the present invention have been described, it is understood that the present invention should not be limited to these exemplary embodiments but various changes and modifications can be made by one ordinary skilled in the art within the spirit and scope of the present invention as hereinafter claimed.