Abstract:
An X-ray detector and an X-ray image system using the same are disclosed. The X-ray image system comprises an X-ray generator irradiating X-rays to an object to be photographed; an X-ray detector including a first photoelectric converter receiving X-rays transmitted the object and converting the X-rays in to a first electric signal and a second photoelectric converter converting the X-rays in to a second electric signal; a first image processor processing a first image of the object on the basis of the first electric signal of the X-ray detector; a second image processor processing a second image of the object on the basis of the second electric signal of the X-ray detector; a display module displaying the first and second processed images of the object; and a controller controlling the X-ray generator, the X-ray detector, the first and second image processors and the display module.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    Pursuant to 35 U.S.C. §119(a), this application claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2016-0067961, filed on Jun. 1, 2016, the contents of which are all hereby incorporated by reference herein in its entirety. 
       BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0002]    The present invention relates to an X-ray detector comprising a scintillator and an X-ray image system using the same. 
       Discussion of the Related Art 
       [0003]    Generally, an X-ray detector is a system that transmits X-rays through an object, e.g., human body, and detects the amount of the transmitted X-rays to photograph the interior of the object. 
         [0004]    The X-ray detector is generally used for a medical testing device and a non-destructive testing device. 
         [0005]    In early days, an X-ray detector photographed the interior of an object by using an X-ray photosensitive film. However, such an X-ray detector has problems in that there is inconvenience to exchange the film with new one several times whenever the interior of an object is photographed and a memory for storing the film having the photographed interior of the object is additionally required. 
         [0006]    Therefore, in recent years, an X-ray detector photographs the interior of an object by using a computed radiography (CR) method or a digital radiography (DR) method instead of the X-ray photosensitive film. 
         [0007]    Such an X-ray detector may be implemented as a flat type X-ray detector based on a solid imaging element such as an active matrix, CCD, and CMOS. 
         [0008]    The flat type X-ray detector may include a photoelectric conversion substrate converting light to an electric signal and a scintillator layer which is in contact with the photoelectric conversion substrate. 
         [0009]    Therefore, if X-rays are irradiated to the scintillator layer, the flat type X-ray detector converts X-rays to light, and if the converted light enters the photoelectric conversion substrate, converts the light to an electric signal, thereby outputting X-ray photographed image or real-time X-ray image as a digital signal. 
         [0010]    However, the existing X-ray detector may generate light loss due to diffusion and reflection of light as the light does not enter the photoelectric conversion substrate when X-rays are converted to the light in the scintillator layer. 
         [0011]    Such light loss may deteriorate detection efficiency of X-rays, and may also deteriorate definition of X-ray photographed image. 
         [0012]    Therefore, the development of an X-ray detector, which may improve definition of X-ray photographed image by increasing X-ray detection efficiency, will be required. 
       SUMMARY OF THE INVENTION 
       [0013]    Accordingly, the present invention is directed to an X-ray detector and an X-ray image system using the same that substantially obviates one or more problems due to limitations and disadvantages of the related art. 
         [0014]    An object of the present invention is to provide an X-ray detector and an X-ray image system using the same, in which photoelectric converters are respectively arranged on an upper surface and a lower surface of a scintillator layer to improve detection efficiency of X-rays. 
         [0015]    Another object of the present invention is to provide an X-ray detector and an X-ray image system using the same, in which a thickness of a photoelectric converter disposed on an upper surface of a scintillator layer is reduced to enable a slim size and miniaturization. 
         [0016]    Still another object of the present invention is to provide an X-ray detector and an X-ray image system using the same, in which a block layer is disposed between adjacent photoelectric conversion layers to improve picture quality of an image by using a small amount of X-rays. 
         [0017]    Further still another object of the present invention is to provide an X-ray detector and an X-ray image system using the same, in which light paths are disposed in a scintillator layer to reduce light loss. 
         [0018]    Further still another object of the present invention is to provide an X-ray detector and an X-ray image system using the same, in which total reflective films are disposed at both sides of a scintillator layer to reduce light loss. 
         [0019]    Further still another object of the present invention is to provide an X-ray detector and an X-ray image system using the same, in which images acquired from a plurality of photoelectric converters are compared with each other to selectively display an image of high picture quality. 
         [0020]    Further still another object of the present invention is to provide an X-ray detector and an X-ray image system using the same, in which images acquired from a plurality of photoelectric converters are overlapped with each other to improve picture quality of an image. 
         [0021]    Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
         [0022]    To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, an X-ray detector according to one embodiment of the present invention comprises a scintillator layer converting externally incident X-rays to light; and a photoelectric converter converting the converted light to an electric signal, wherein the photoelectric converter includes a first photoelectric converter disposed on an upper surface of the scintillator layer where the X-rays enter, and a second photoelectric converter disposed on a lower surface of the scintillator layer. 
         [0023]    In another aspect of the present invention, an X-ray image system using an X-ray detector comprises an X-ray generator irradiating X-rays to an object to be photographed; an X-ray detector including a first photoelectric converter receiving X-rays transmitted the object and converting the X-rays to a first electric signal and a second photoelectric converter converting the X-rays to a second electric signal; a first image processor processing a first image of the object on the basis of the first electric signal of the X-ray detector; a second image processor processing a second image of the object on the basis of the second electric signal of the X-ray detector; a display module displaying the first and second processed images of the object; and a controller controlling the X-ray generator, the X-ray detector, the first and second image processors and the display module. 
         [0024]    It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    Arrangements and embodiments may be described in detail with reference to the following drawings in which like reference numerals refer to like elements and wherein: 
           [0026]      FIG. 1  is a block diagram illustrating an X-ray image system using an X-ray detector according to the present invention; 
           [0027]      FIGS. 2 and 3  are structural cross-sectional diagrams illustrating an X-ray detector according to the first embodiment of the present invention; 
           [0028]      FIGS. 4 and 5  are structural cross-sectional diagrams illustrating an X-ray detector according to the second embodiment of the present invention; 
           [0029]      FIGS. 6 and 7  are structural cross-sectional diagrams illustrating an X-ray detector according to the third embodiment of the present invention; 
           [0030]      FIGS. 8 to 10  are structural cross-sectional diagrams illustrating an X-ray detector according to the fourth embodiment of the present invention; 
           [0031]      FIGS. 11 and 12  are structural cross-sectional diagrams illustrating an X-ray detector according to the fifth embodiment of the present invention; 
           [0032]      FIG. 13  is a structural cross-sectional diagram illustrating an X-ray detector according to the sixth embodiment of the present invention; 
           [0033]      FIG. 14  is a structural cross-sectional diagram illustrating an X-ray detector according to the seventh embodiment of the present invention; 
           [0034]      FIG. 15  is a structural cross-sectional diagram illustrating an X-ray detector according to the eighth embodiment of the present invention; 
           [0035]      FIG. 16  is a structural cross-sectional diagram illustrating an X-ray detector according to the ninth embodiment of the present invention; 
           [0036]      FIGS. 17 to 19  are structural cross-sectional diagrams illustrating an X-ray detector according to the tenth embodiment of the present invention; 
           [0037]      FIGS. 20 to 23  are structural cross-sectional diagrams illustrating an X-ray detector according to the eleventh embodiment of the present invention; and 
           [0038]      FIGS. 24 and 25  are structural cross-sectional diagrams illustrating an X-ray detector according to the twelfth embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0039]    Reference will now be made in detail to the preferred embodiments of the present specification, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. The suffixes “module” and “unit” for the elements used in the following description are given or used in common by considering facilitation in writing this disclosure only but fail to have meanings or roles discriminated from each other. Also, in description of the embodiments disclosed in this specification, if detailed description of the disclosure known in respect of the present invention is determined to make the subject matter of the embodiments disclosed in this specification obscure, the detailed description will be omitted. Also, the accompanying drawings are only intended to facilitate understanding of the embodiments disclosed in this specification, and it is to be understood that technical spirits disclosed in this specification are not limited by the accompanying drawings and the accompanying drawings include all modifications, equivalents or replacements included in technical spirits and technical scope of the present invention. 
         [0040]    Although the terms such as “first” and/or “second” in this specification may be used to describe various elements, it is to be understood that the elements are not limited by such terms. The terms may be used to identify one element from another element. 
         [0041]    The expression that an element is “connected” or “coupled” to another element should be understood that the element may directly be connected or coupled to another element, a third element may be interposed between the corresponding elements, or the corresponding elements may be connected or coupled to each other through a third element. On the other hand, the expression that an element is “directly connected” or “directly coupled” to another element” means that no third element exists therebetween. 
         [0042]    It is to be understood that the singular expression used in this specification includes the plural expression unless defined differently on the context. 
         [0043]    In this application, it is to be understood that the terms such as “include” and “has” are intended to designate that features, numbers, steps, operations, elements, parts, or their combination, which are disclosed in the specification, exist, and are intended not to previously exclude the presence or optional possibility of one or more other features, numbers, steps, operations, elements, parts, or their combinations. 
         [0044]      FIG. 1  is a block diagram illustrating an X-ray image system using an X-ray detector according to the present invention. 
         [0045]    As shown in  FIG. 1 , an X-ray image system may include an X-ray generator  200 , an X-ray detector  100 , a first image processor  310 , a second image processor  320 , a display module  400 , and a controller  500 . 
         [0046]    In this case, the X-ray generator  200  may irradiate X-rays to an object  10 , which is desired to be photographed, in accordance with a control signal of the controller  500 . 
         [0047]    Then, the X-ray detector  100  may receive the X-rays transmitted the object  10  and convert the X-rays to electric signals. The X-ray detector  100  may include a first photoelectric converter  120  disposed on an upper surface of a scintillator layer  110 , and a second photoelectric converter  130  disposed on a lower surface of the scintillator layer  110 . For example, the scintillator layer  110  of the X-ray detector  100  converts the X-rays incident by transmitting the object  10  to light, the first photoelectric converter  120  converts the light converted by the scintillator layer  110  to a first electric signal, and the second photoelectric converter  130  converts the light converted by the scintillator layer  110  to a second electric signal. 
         [0048]    The scintillator layer  110  may be made of CsI, NaI, LiF, GOS (Gadolinium Oxysulfide), or the like. 
         [0049]    The first photoelectric converter  120  may include a first substrate having a plurality of pixel areas, a first photoelectric conversion layer disposed on the pixel areas of the first substrate, converting light to an electric signal, and a first transistor disposed between the first substrate and the first photoelectric conversion layer, outputting the converted electric signal. 
         [0050]    Also, the second photoelectric converter  130  may include a second substrate having a plurality of pixel areas, a second photoelectric conversion layer disposed on the pixel areas of the second substrate, converting light to an electric signal, and a second transistor disposed between the second substrate and the second photoelectric conversion layer, outputting the converted electric signal. 
         [0051]    Then, the first image processor  310  may electrically be connected to the first photoelectric converter  120  to process a first image of the object  10  on the basis of the first electric signal output from the first photoelectric converter  120 . 
         [0052]    The second image processor  320  may electrically be connected to the second photoelectric converter  130  to process a second image of the object  10  on the basis of the second electric signal output from the second photoelectric converter  130 . 
         [0053]    Subsequently, the display module  400  may display the first and second images of the object, which are processed from the first and second image processors  310  and  320 . 
         [0054]    Then, the controller  500  may control the X-ray generator  200 , the X-ray detector  100 , the first and second image processors  310  and  320 , and the display module  400 . 
         [0055]    In this case, the controller  500  may synthesize the first image processed from the first image processor  310  with the second image processed from the second image processor  320  to display the synthesized image on the display module  400 . This is because that an image of picture quality clearer than that of the first image acquired from the first photoelectric converter  120  disposed on the upper surface of the scintillator  110  or the second image acquired from the second photoelectric converter  130  disposed on the lower surface of the scintillator  110  if the first image and the second image are synthesized. 
         [0056]    That is, the controller  500  may display a photographed image of an object in such a manner that the first image and the second image are synthesized, if the X-ray detector  100  has a structure that a first photoelectric conversion layer of the first photoelectric converter  120  disposed on the upper surface of the scintillator layer  110  and a second photoelectric conversion layer of the second photoelectric converter  130  disposed on the lower surface of the scintillator layer  110  are disposed to correspond to each other one to one. This is because that the first image acquired from the first photoelectric converter  120  and the second image acquired from the second photoelectric converter  130  are the same as each other if the first photoelectric conversion layer of the first photoelectric converter  120  disposed on the upper surface of the scintillator layer  110  and the second photoelectric conversion layer of the second photoelectric converter  130  disposed on the lower surface of the scintillator layer  110  are disposed to correspond to each other one to one. 
         [0057]    Therefore, the controller  500  may overlap the first image and the second image with each other to improve picture quality of the overlapped image area, and may obtain a clear image even though a small amount of incident X-rays are provided. 
         [0058]    As another case, the controller  500  may synthesize some of the first image processed from the first image processor  310  with some of the second image processed from the second image processor  320  to display the synthesized image on the display module  400 . This is because that an image of picture quality clearer than that of the first image acquired from the first photoelectric converter  120  disposed on the upper surface of the scintillator  110  or the second image acquired from the second photoelectric converter  130  disposed on the lower surface of the scintillator  110  if some of the first image and some of the second image are synthesized. 
         [0059]    That is, the controller  500  may display a photographed image of an object in such a manner that some of the first image and some of the second image are synthesized, if the X-ray detector  100  has a structure that the first photoelectric conversion layer of the first photoelectric converter  120  disposed on the upper surface of the scintillator layer  110  and the second photoelectric conversion layer of the second photoelectric converter  130  disposed on the lower surface of the scintillator layer  110  are disposed alternately with each other. This is because that some of the first image acquired from the first photoelectric converter  120  and some of the second image acquired from the second photoelectric converter  130  are the same as each other if the first photoelectric conversion layer of the first photoelectric converter  120  disposed on the upper surface of the scintillator layer  110  and the second photoelectric conversion layer of the second photoelectric converter  130  disposed on the lower surface of the scintillator layer  110  are disposed alternately with each other. 
         [0060]    Therefore, the controller  500  may overlap some of the first image and some of the second image with each other to improve picture quality of the overlapped image area, and may obtain a clear image even though a small amount of incident X-rays are provided. 
         [0061]    As still another case, the controller  500  may compare picture quality of the first image processed from the first image processor  310  with picture quality of the second image processed from the second image processor  320  to display the image having higher picture quality on the display module  400 . This is because that an image of clear picture quality may be obtained even though picture quality is deteriorated due to a defect occurring in the first image acquired from the first photoelectric converter  120  disposed on the upper surface of the scintillator  110  or the second image acquired from the second photoelectric converter  130  disposed on the lower surface of the scintillator  110 . 
         [0062]    Therefore, the controller  500  may obtain an image of high picture quality without breaking image photographing even though a defect occurs in the X-ray detector  100 . 
         [0063]    As further still another case, the controller  500  may display the first image processed from the first image processor  310  or the second image processed from the second image processor  320  on the display module  400  if intensity of X-rays is greater than a reference value, display the first image processed from the first image processor  310  on the display module  400  if intensity of X-rays is the reference value, and synthesize the first image processed from the first image processor  310  with the second image processed from the second image processor  320  to display the synthesized image on the display module  400  if intensity of X-rays is smaller than the reference value. This is because that picture quality of the first image acquired from the first photoelectric converter  120  disposed on the upper surface of the scintillator  110  may be clearer than picture quality of the second image acquired from the second photoelectric converter  130  disposed on the lower surface of the scintillator  110  as the first photoelectric converter  120  is disposed on an upper surface of the scintillator  110 , where X-rays enter. 
         [0064]    Therefore, if intensity of X-rays is greater than the reference value, since picture quality of the first image acquired from the first photoelectric converter  120  disposed on the upper surface of the scintillator  110  or picture quality of the second image acquired from the second photoelectric converter  130  disposed on the lower surface of the scintillator  110  is clear, the controller  500  may select any one of the first and second images. And, if intensity of X-rays is the reference value, since picture quality of the first image acquired from the first photoelectric converter  120  disposed on the upper surface of the scintillator  110  is clearer than picture quality of the second image acquired from the second photoelectric converter  130  disposed on the lower surface of the scintillator  110 , the controller  500  may select the first image. Subsequently, if intensity of X-rays is smaller than the reference value, since picture quality of the first image acquired from the first photoelectric converter  120  disposed on the upper surface of the scintillator  110  and picture quality of the second image acquired from the second photoelectric converter  130  disposed on the lower surface of the scintillator  110  are all deteriorated, the controller  500  may synthesize the first image and the second image with each other. 
         [0065]    As described above, according to the present invention, since the X-ray detector provided with the photoelectric converters disposed on the upper surface and the lower surface of the scintillator layer is used, detection efficiency of the X-rays may be increased, whereby picture quality of the image may be improved. 
         [0066]      FIGS. 2 and 3  are structural cross-sectional diagrams illustrating an X-ray detector according to the first embodiment of the present invention. 
         [0067]    As shown in  FIGS. 2 and 3 , the X-ray detector may include a scintillator layer  110  and a photoelectric conversion module that includes first and second photoelectric converters  120  and  130 . 
         [0068]    The scintillator layer  110  may convert externally incident X-rays  20  to light  30 , and the photoelectric conversion module, which includes the first and second photoelectric converters  120  and  13 , may convert the converted light to an electric signal. 
         [0069]    In this case, the first photoelectric converter  120  may be disposed on an upper surface of the scintillator layer  110  where the X-rays  20  enter, and the second photoelectric converter  130  may be disposed on a lower surface of the scintillator layer  110 . 
         [0070]    For example, the scintillator layer  110  may be made of CsI, NaI, LiF, GOS (Gadolinium Oxysulfide), or the like. 
         [0071]    The first photoelectric converter  120  may include a first substrate having a plurality of pixel areas, a first photoelectric conversion layer disposed on the pixel areas of the first substrate, converting light to an electric signal, and a first transistor disposed between the first substrate and the first photoelectric conversion layer, outputting the converted electric signal. 
         [0072]    Also, the second photoelectric converter  130  may include a second substrate having a plurality of pixel areas, a second photoelectric conversion layer disposed on the pixel areas of the second substrate, converting light to an electric signal, and a second transistor disposed between the second substrate and the second photoelectric conversion layer, outputting the converted electric signal. 
         [0073]    Subsequently, as shown in  FIG. 2 , a thickness t 1  of the first photoelectric converter  120  may be different from a thickness t 2  of the second photoelectric converter  130 . For example, the thickness t 1  of the first photoelectric converter  120  may be thinner than the thickness t 2  of the second photoelectric converter  130 . This is because that a too thick thickness of the first photoelectric converter  120  could lead to loss of some of the incident X-rays as the first photoelectric converter  120  is disposed on the upper surface of the scintillator layer  110  where the X-rays enter. 
         [0074]    As the case may be, the thickness t 1  of the first photoelectric converter  120  may be the same as the thickness t 2  of the second photoelectric converter  130  as shown in  FIG. 3 . 
         [0075]    As described above, according to the present invention, the thickness of the photoelectric converter disposed on the upper surface of the scintillator layer may be reduced to enable a slim size and miniaturization. 
         [0076]      FIGS. 4 and 5  are structural cross-sectional diagrams illustrating an X-ray detector according to the second embodiment of the present invention. 
         [0077]    As shown in  FIGS. 4 and 5 , the X-ray detector may include a scintillator layer  110  and a photoelectric conversion module that includes first and second photoelectric converters  120  and  130 . 
         [0078]    The first photoelectric converter  120  may include a first substrate  121  having a plurality of pixel areas, a first photoelectric conversion layer  125  disposed on the pixel areas of the first substrate  121 , converting light to an electric signal, and a first transistor  123  disposed between the first substrate  121  and the first photoelectric conversion layer  125 , outputting the converted electric signal. In this case, the first transistor  123  may include a gate electrode  123   a , a source electrode  123   b , a drain electrode  123   c , and a pixel electrode  123   d . The first photoelectric conversion layer  125  may be formed on the pixel electrode  123   d  of the first transistor  123 . 
         [0079]    Subsequently, the second photoelectric converter  130  may include a second substrate  131  having a plurality of pixel areas, a second photoelectric conversion layer  135  disposed on the pixel areas of the second substrate  131 , converting light to an electric signal, and a second transistor  133  disposed between the second substrate  131  and the second photoelectric conversion layer  135 , outputting the converted electric signal. In this case, the second transistor  133  may include a gate electrode  133   a , a source electrode  133   b , a drain electrode  133   c , and a pixel electrode  133   d . The second photoelectric conversion layer  135  may be formed on the pixel electrode  133   d  of the second transistor  133 . 
         [0080]    The first photoelectric conversion layer  125  of the first photoelectric converter  120  and the second photoelectric conversion layer  135  of the second photoelectric converter  130  may be disposed to correspond to each other one to one to face each other. 
         [0081]    Meanwhile, as shown in  FIG. 4 , a thickness t 3  of the first substrate  121  of the first photoelectric converter  120  may be different from a thickness t 4  of the second substrate  131  of the second photoelectric converter  130 . For example, the thickness t 3  of the first substrate  121  of the first photoelectric converter  120  may be thinner than the thickness t 4  of the second substrate  131  of the second photoelectric converter  130 . This is because that a too thick thickness of the first substrate  121  of the first photoelectric converter  120  could lead to loss of some of the incident X-rays as the first photoelectric converter  120  is disposed on the upper surface of the scintillator layer  110  where the X-rays enter. 
         [0082]    However, the thickness t 3  of the first substrate  121  of the first photoelectric converter  120  may be the same as the thickness t 4  of the second substrate  131  of the second photoelectric converter  130  as shown in  FIG. 5 . 
         [0083]    As another case, X-ray transmittance of the first substrate  121  of the first photoelectric converter  120  may be different from X-ray transmittance of the second substrate  131  of the second photoelectric converter  130 . For example, X-ray transmittance of the first substrate  121  of the first photoelectric converter  120  may be higher than X-ray transmittance of the second substrate  131  of the second photoelectric converter  130 . This is because that low X-ray transmittance of the first substrate  121  of the first photoelectric converter  120  could lead to loss of some of the incident X-rays as the first photoelectric converter  120  is disposed on the upper surface of the scintillator layer  110  where the X-rays enter. 
         [0084]    However, X-ray transmittance of the first substrate  121  of the first photoelectric converter  120  may be the same as X-ray transmittance of the second substrate  131  of the second photoelectric converter  130 . 
         [0085]    Also, each of the first substrate  121  of the first photoelectric converter  120  and the second substrate  131  of the second photoelectric converter  130  may be, but not limited to, at least any one of carbon, carbon fiber reinforced plastic, glass, crystal, sapphire, and metal, wherein the metal may be any one of Fe, Sn, Cr, and Al. In this case, the first substrate  121  of the first photoelectric converter  120  and the second substrate  131  of the second photoelectric converter  130  may be made of their respective materials different from each other depending on X-ray transmittance. 
         [0086]    As described above, according to the present invention, the thickness of the substrate of the photoelectric converter disposed on the upper surface of the scintillator layer may be reduced, or X-ray transmittance of the substrate may be increased, whereby loss of incident X-rays may be minimized 
         [0087]      FIGS. 6 and 7  are structural cross-sectional diagrams illustrating an X-ray detector according to the third embodiment of the present invention. 
         [0088]    As shown in  FIGS. 6 and 7 , the X-ray detector may include a scintillator layer  110  and a photoelectric conversion module that includes first and second photoelectric converters  120  and  130 . The first photoelectric conversion layer  125  of the first photoelectric converter  120  and the second photoelectric conversion layer  135  of the second photoelectric converter  130  may be disposed alternately with each other. If the first photoelectric conversion layer  125  of the first photoelectric converter  120  and the second photoelectric conversion layer  135  of the second photoelectric converter  130  are disposed alternately with each other, since light may be detected uniformly without light loss from the entire area of the scintillator layer  110  as compared with the structure that the first photoelectric conversion layer  125  of the first photoelectric converter  120  and the second photoelectric conversion layer  135  of the second photoelectric converter  130  are disposed to correspond to each other, picture quality of the image may be improved. 
         [0089]    Since the X-ray detector according to the third embodiment of the present invention is the same as the X-ray detector according to the second embodiment of the present invention except that the first photoelectric conversion layer  125  of the first photoelectric converter  120  and the second photoelectric conversion layer  135  of the second photoelectric converter  130  are disposed alternately with each other, its detailed description will be omitted. 
         [0090]      FIGS. 8 to 10  are structural cross-sectional diagrams illustrating an X-ray detector according to the fourth embodiment of the present invention. 
         [0091]    As shown in  FIGS. 8 to 10 , the X-ray detector may include a scintillator layer  110  and a photoelectric conversion module that includes first and second photoelectric converters  120  and  130 . 
         [0092]    The first photoelectric converter  120  may include a first substrate  121  having a plurality of pixel areas, a first photoelectric conversion layer  125  disposed on the pixel areas of the first substrate  121 , converting light to an electric signal, and a first transistor  123  disposed between the first substrate  121  and the first photoelectric conversion layer  125 , outputting the converted electric signal. In this case, the first transistor  123  may include a gate electrode  123   a , a source electrode  123   b , a drain electrode  123   c , and a pixel electrode  123   d . The first photoelectric conversion layer  125  may be formed on the pixel electrode  123   d  of the first transistor  123 . 
         [0093]    Subsequently, the second photoelectric converter  130  may include a second substrate  131  having a plurality of pixel areas, a second photoelectric conversion layer  135  disposed on the pixel areas of the second substrate  131 , converting light to an electric signal, and a second transistor  133  disposed between the second substrate  131  and the second photoelectric conversion layer  135 , outputting the converted electric signal. In this case, the second transistor  133  may include a gate electrode  133   a , a source electrode  133   b , a drain electrode  133   c , and a pixel electrode  133   d . The second photoelectric conversion layer  135  may be formed on the pixel electrode  133   d  of the second transistor  133 . 
         [0094]    Meanwhile, the first substrate of the first photoelectric converter  120  may include a block layer  150  that blocks incident X-rays  20 . In this case, the block layer  150  may be disposed between the first photoelectric conversion layers  125  which are adjacent to each other. That is, the first photoelectric conversion layer  125  may be formed on a lower surface of the first substrate  121 , which faces the scintillator layer  110 , and the block layer  150  may be formed on the upper surface of the first substrate  121  where X-rays  20  enter. If the block layer  150  is formed, since the X-rays intensively enter the area where the first photoelectric conversion layer  125  is disposed, detection efficiency of light converted from the X-rays may be increased. 
         [0095]    As the case may be, a thickness t 12  of the area of the first substrate  121  where the block layer  150  is formed may be thicker than a thickness t 11  of the other area of the first substrate  121  as shown in  FIG. 9 . For example, the first substrate  121  may be provided with a groove  127  formed between the block layers  150  which are adjacent to each other. In this case, a side  129  of the groove  127  may be inclined. This is because that the side  129  of the groove  127  may stably support the block layer  150 . 
         [0096]    As another case, the first substrate  121  may be provided with a support protrusion  160  formed on the area where the block layer  150  is formed, to support the block layer  150 . In this case, the side of the support protrusion  160  may be inclined. This is because that the side of the support protrusion  160  may stably support the block layer  150 . For example, the support protrusion  160  may be formed of a material different from that of the first substrate  121 . 
         [0097]    In the X-ray detector of  FIGS. 8 to 10 , the first photoelectric conversion layer  125  of the first photoelectric converter  120  and the second photoelectric conversion layer  135  of the second photoelectric converter  130  may be disposed to correspond to each other one to one to face each other, or may be disposed alternately with each other as the case may be. 
         [0098]    The thickness t 3  of the first substrate  121  of the first photoelectric converter  120  may be thinner than the thickness t 4  of the second substrate  131  of the second photoelectric converter  130 . Since the first photoelectric converter  120  is disposed on the upper surface of the scintillator layer  110  where the X-rays enter, if the thickness t 3  of the first substrate  121  of the first photoelectric converter  120  is too thick, it could lead to loss of some of the incident X-rays. Therefore, the thickness t 3  of the first substrate  121  is thicker than the thickness t 4  of the second substrate  131 . 
         [0099]    However, the thickness t 3  of the first substrate  121  of the first photoelectric converter  120  may be the same as the thickness t 4  of the second substrate  131  of the second photoelectric converter  130 . 
         [0100]    As another case, X-ray transmittance of the first substrate  121  of the first photoelectric converter  120  may be higher than X-ray transmittance of the second substrate  131  of the second photoelectric converter  130 . This is because that low X-ray transmittance of the first substrate  121  of the first photoelectric converter  120  could lead to loss of some of the incident X-rays as the first photoelectric converter  120  is disposed on the upper surface of the scintillator layer  110  where the X-rays enter. 
         [0101]    However, X-ray transmittance of the first substrate  121  of the first photoelectric converter  120  may be the same as X-ray transmittance of the second substrate  131  of the second photoelectric converter  130 . 
         [0102]    As described above, according to the present invention, the block layer may be disposed between the photoelectric conversion layers adjacent to each other to improve picture quality of an image through a small amount of X-rays, whereby an exposure rate may be minimized. 
         [0103]      FIGS. 11 and 12  are structural cross-sectional diagrams illustrating an X-ray detector according to the fifth embodiment of the present invention. 
         [0104]    As shown in  FIGS. 11 and 12 , the X-ray detector may include a scintillator layer  110  and a photoelectric conversion module that includes first and second photoelectric converters  120  and  130 . 
         [0105]    The first photoelectric converter  120  may include a first photoelectric conversion layer  125  disposed on pixel areas of a first substrate  121 , converting light to an electric signal, and the second photoelectric converter  130  may include a second photoelectric conversion layer  135  disposed on pixel areas of a second substrate  131 , converting light to an electric signal. In this case, although the first and second photoelectric conversion layers  125  and  135  may directly be in contact with the scintillator layer  110 , the first and second photoelectric conversion layers  125  and  135  may be disposed to be spaced apart from the scintillator layer  110  at a certain interval as shown in  FIGS. 11 and 12 . 
         [0106]    As shown in  FIGS. 11 and 12 , if the first and second photoelectric conversion layers  125  and  135  are disposed to be spaced apart from the scintillator layer  110  at a certain interval, a first adhesive layer  170  may be formed between the first photoelectric conversion layer  125  and the scintillator layer  110 , and a second adhesive layer  180  may be formed between the second photoelectric conversion layer  135  and the scintillator layer  110 . This is to prevent the scintillator layer  180  and the photoelectric conversion layers from being detached from each other by external impact. In this case, as shown in  FIG. 11 , a thickness t 21  of the first adhesive layer  170  may be thinner than a thickness t 22  of the second adhesive layer  180 . This is because that a too thick thickness of the first adhesive layer  170  could lead to loss of some of incident X-rays as the first adhesive layer  170  is disposed on the upper surface of the scintillator layer  110  where the X-rays enter. 
         [0107]    However, as shown in  FIG. 12 , the thickness t 21  of the first adhesive layer  170  may be the same as the thickness t 22  of the second adhesive layer  180 . 
         [0108]    Also, in the X-ray detector of  FIGS. 11 and 12 , the first photoelectric conversion layer  125  of the first photoelectric converter  120  and the second photoelectric conversion layer  135  of the second photoelectric converter  130  may be disposed to correspond to each other one to one to face each other, or may be disposed alternately with each other as the case may be. 
         [0109]    The thickness t 3  of the first substrate  121  of the first photoelectric converter  120  may be thinner than the thickness t 4  of the second substrate  131  of the second photoelectric converter  130 . This is because that a too thick thickness of the first substrate  121  of the first photoelectric converter  120  could lead to loss of some of the incident X-rays as the first photoelectric converter  120  is disposed on the upper surface of the scintillator layer  110  where the X-rays enter. 
         [0110]    However, the thickness t 3  of the first substrate  121  of the first photoelectric converter  120  may be the same as the thickness t 4  of the second substrate  131  of the second photoelectric converter  130 . 
         [0111]    As another case, X-ray transmittance of the first substrate  121  of the first photoelectric converter  120  may be higher than X-ray transmittance of the second substrate  131  of the second photoelectric converter  130 . This is because that low X-ray transmittance of the first substrate  121  of the first photoelectric converter  120  could lead to loss of some of the incident X-rays as the first photoelectric converter  120  is disposed on the upper surface of the scintillator layer  110  where the X-rays enter. 
         [0112]    However, X-ray transmittance of the first substrate  121  of the first photoelectric converter  120  may be the same as X-ray transmittance of the second substrate  131  of the second photoelectric converter  130 . 
         [0113]    As described above, according to the present invention, the thickness of the adhesive layer disposed on the upper surface of the scintillator layer may be reduced, whereby loss of the incident X-rays may be minimized. 
         [0114]      FIG. 13  is a structural cross-sectional diagram illustrating an X-ray detector according to the sixth embodiment of the present invention. 
         [0115]    As shown in  FIG. 13 , in the X-ray detector, the first and second photoelectric conversion layers  125  and  135  are disposed to be spaced apart from the scintillator layer  110  at a certain interval, wherein the first adhesive layer  170  may be formed between the first photoelectric conversion layer  125  and the scintillator layer  110 , and the second adhesive layer  180  may be formed between the second photoelectric conversion layer  135  and the scintillator layer  180 . In this case, the first adhesive layer  170  may be provided with a first reflective layer  175  formed between the first photoelectric conversion layers  125  adjacent to each other, and the second adhesive layer  180  may be provided with a second reflective layer  185  formed between the second photoelectric conversion layers  135  adjacent to each other. The first and second reflective layers  175  and  185  are formed to block loss of light  30  converted within the scintillator layer  110  from an area between the first photoelectric conversion layers  125  and an area between the second photoelectric conversion layers  135 . For example, the first and second reflective layers  175  and  185  may be made of metal having high reflectivity such as Al, Ni, Cu, Pd and Ag. As the case may be, the first and second reflective layers  175  and  185  may be made of their respective materials different from each other. 
         [0116]    Since the X-ray detector according to the sixth embodiment of the present invention is the same as the X-ray detector according to the fifth embodiment of the present invention except that the first reflective layer  175  and the second reflective layer  185  are disposed, its detailed description will be omitted. 
         [0117]      FIG. 14  is a structural cross-sectional diagram illustrating an X-ray detector according to the seventh embodiment of the present invention. 
         [0118]    As shown in  FIG. 14 , in the X-ray detector, the first photoelectric conversion layer  125  may directly be in contact with the scintillator layer  110 , and the second photoelectric conversion layer  135  may be disposed to be spaced apart from the scintillator layer  110  at a certain interval. In this case, the second adhesive layer  180  may be formed between the second photoelectric conversion layer  135  and the scintillator layer  110 . The second adhesive layer  180  is formed to prevent the scintillator layer  180  and the second photoelectric conversion layer  135  from being detached from each other by external impact. As shown in  FIG. 14 , the first adhesive layer  180  is not formed between the first photoelectric conversion layer  125  and the scintillator layer  110  but the second adhesive layer  180  is formed between the second photoelectric conversion layer  135  and the scintillator layer  110 . This is because that the adhesive layer formed between the first photoelectric conversion layer  125  and the scintillator layer  110  could lead to loss of some of the X-rays as the first photoelectric conversion layer  125  is disposed on the upper surface of the scintillator layer  110  where the X-rays enter. 
         [0119]    Since the X-ray detector according to the seventh embodiment of the present invention is the same as the X-ray detector according to the fifth embodiment of the present invention except that the second adhesive layer  180  is only formed between the second photoelectric conversion layer  135  and the scintillator layer  110 , its detailed description will be omitted. 
         [0120]      FIG. 15  is a structural cross-sectional diagram illustrating an X-ray detector according to the eighth embodiment of the present invention. 
         [0121]    As shown in  FIG. 15 , in the X-ray detector, the first photoelectric conversion layer  125  may directly be in contact with the scintillator layer  110 , and the second photoelectric conversion layer  135  may be disposed to be spaced apart from the scintillator layer  110  at a certain interval. In this case, the second adhesive layer  180  may be formed between the second photoelectric conversion layer  135  and the scintillator layer  110 . The second adhesive layer  180  may be provided with the second reflective layer  185  formed between the second photoelectric conversion layers  135  adjacent to each other. In this case, the second reflective layer  185  is formed to block loss of light  30  converted within the scintillator layer  110  from an area between the second photoelectric conversion layers  135 . For example, the second reflective layer  185  may be made of metal having high reflectivity such as Al, Ni, Cu, Pd and Ag. 
         [0122]    Since the X-ray detector according to the eighth embodiment of the present invention is the same as the X-ray detector according to the seventh embodiment of the present invention except that the second adhesive layer  180  is only formed between the second photoelectric conversion layer  135  and the scintillator layer  110 , its detailed description will be omitted. 
         [0123]      FIG. 16  is a structural cross-sectional diagram illustrating an X-ray detector according to the ninth embodiment of the present invention. 
         [0124]    As shown in  FIG. 16 , the X-ray detector may include a scintillator layer  110  and a photoelectric conversion module that includes first and second photoelectric converters  120  and  130 . 
         [0125]    The first photoelectric converter  120  may include a first photoelectric conversion layer  125  disposed on pixel areas of a first substrate  121 , converting light to an electric signal, and the second photoelectric converter  130  may include a second photoelectric conversion layer  135  disposed on pixel areas of a second substrate  131 , converting light to an electric signal. In this case, the number of the first photoelectric conversion layers  125  may be different from the number of the second photoelectric conversion layers  135 . For example, the number of the first photoelectric conversion layers  125  may be more than the number of the second photoelectric conversion layers  135 . This is because that it may be difficult for the second photoelectric conversion layer  135  disposed on the lower surface of the scintillator layer  110  to detect light  30  as the amount of light converted in a lower area of the scintillator layer  110  is less than the amount of light converted in an upper area of the scintillator layer  110  where X-rays enter. 
         [0126]    As described above, the number of the second photoelectric conversion layers  135  disposed on the lower surface of the scintillator layer  110  may be more than the number of the first photoelectric conversion layers  125  disposed on the upper surface of the scintillator layer  110 , whereby light detection efficiency may be increased. 
         [0127]      FIGS. 17 to 19  are structural cross-sectional diagrams illustrating an X-ray detector according to the tenth embodiment of the present invention. 
         [0128]    As shown in  FIGS. 17 to 19 , the X-ray detector may include a scintillator layer  110  and a photoelectric conversion module that includes first and second photoelectric converters  120  and  130 . 
         [0129]    The scintillator layer  110  may convert incident X-rays to light, and may be made of CsI, NaI, LiF, GOS (Gadolinium Oxysulfide), or the like. 
         [0130]    The scintillator layer  110  may include a binder resin  112  and a plurality of fluorescent particles  114 . In this case, as shown in  FIG. 17 , the fluorescent particles  114  may be disposed uniformly within the scintillator layer  110 . 
         [0131]    As the case may be, as shown in  FIG. 18 , a ratio of the fluorescent particles  114  may be higher in the area adjacent to the lower surface of the scintillator layer  110  than in the area adjacent to the upper surface of the scintillator layer  110 . This is because that it may be difficult for the second photoelectric conversion layer  135  disposed on the lower surface of the scintillator layer  110  to detect light  30  as the X-ray incident amount is smaller in the lower area of the scintillator layer  110  than in the upper area of the scintillator layer  110 . 
         [0132]    As another case, as shown in  FIG. 19 , the ratio of the fluorescent particles  114  may be increased gradiently from the upper surface of the scintillator layer  110  to the lower surface of the scintillator layer  110 . This is because that it may be difficult for the second photoelectric conversion layer  135  disposed on the lower surface of the scintillator layer  110  to detect light  30  as the X-ray incident amount is smaller in the lower area of the scintillator layer  110  than in the upper area of the scintillator layer  110 . 
         [0133]    As described above, according to the present invention, the ratio of the fluorescent particles  114  may be increased from the upper surface of the scintillator layer  110  to the lower surface of the scintillator layer  110 , whereby light detection efficiency may be increased. 
         [0134]      FIGS. 20 to 23  are structural cross-sectional diagrams illustrating an X-ray detector according to the eleventh embodiment of the present invention. 
         [0135]    As shown in  FIGS. 20 to 23 , the X-ray detector may include a scintillator layer  110  and a photoelectric conversion module that includes first and second photoelectric converters  120  and  130 . 
         [0136]    The scintillator layer  110  may have a columnar crystal structure that a plurality of strip shaped columnar crystals are formed from the upper surface to the lower surface. In this case, the columnar crystals may be used as light paths  115  of the scintillator layer  110 . For example, the scintillator layer  110  may be provided with a plurality of light paths  115  formed from the upper surface to the lower surface at predetermined intervals. In this way, the light paths  115  are formed in the scintillator layer  110  to detect light  30  condensed on the photoelectric conversion layer only without light loss. 
         [0137]    The light paths  115  may be disposed in various arrangements in accordance with an arrangement relation between the first photoelectric conversion layer  125  of the first photoelectric converter  120  and the second photoelectric conversion layer  135  of the second photoelectric converter  130 . For example, as shown in  FIG. 20 , if the first photoelectric conversion layer  125  of the first photoelectric converter  120  and the second photoelectric conversion layer  135  of the second photoelectric converter  130  are disposed to correspond to each other one to one, one side of the light paths  115  may be formed to correspond to the first photoelectric conversion layer  125  of the first photoelectric converter  120  and the other side of the light paths  115  may be formed to correspond to the second photoelectric conversion layer  135  of the second photoelectric converter  130 . That is, a front end of the light paths  115  may be opened to correspond to the first photoelectric conversion layer  125  of the first photoelectric converter  120 , and a rear end of the light paths  115  may be opened to correspond to the second photoelectric conversion layer  135  of the second photoelectric converter  130 . 
         [0138]    As another case, as shown in  FIG. 21 , if the first photoelectric conversion layer  125  of the first photoelectric converter  120  and the second photoelectric conversion layer  135  of the second photoelectric converter  130  are disposed alternately with each other, the light paths may include a first light path  117  corresponding to the first photoelectric conversion layer  125  of the first photoelectric converter  120  and a second light path  119  corresponding to the second photoelectric conversion layer  135  of the second photoelectric converter  130 . That is, a front end of the first light path  117  may be opened to correspond to the first photoelectric conversion layer  125  of the first photoelectric converter  120 , and a rear end of the first light path  117  may be blocked by a first reflective film  220 . And, a front end of the second light path  119  may be blocked by a second reflective film  210 , and a rear end of the second light path  119  may be opened to correspond to the second photoelectric conversion layer  135  of the second photoelectric converter  130 . The first and second reflective films  220  and  210  are formed to increase light detection efficiency by minimizing light loss. 
         [0139]    As another case, the first reflective film  220  disposed at the rear end of the first light path  117  and the second reflective film  210  disposed at the front end of the second light path  119  may be removed. 
         [0140]    As still another case, as shown in  FIG. 22 , a plurality of fluorescent particles  114  may be formed inside the light paths  115 . The scintillator layer  110  inside the light paths  115  may include a binder resin  112  and a plurality of fluorescent particles  114 . In this case, the fluorescent particles  114  may be disposed uniformly within the light paths of the scintillator layer  110 . 
         [0141]    As the case may be, a ratio of the fluorescent particles  114  may be higher in the area adjacent to the lower surface of the scintillator layer  110  than in the area adjacent to the upper surface of the scintillator layer  110 . This is because that it may be difficult for the second photoelectric conversion layer  135  disposed on the lower surface of the scintillator layer  110  to detect light  30  as the X-ray incident amount is smaller in the lower area of the scintillator layer  110  than in the upper area of the scintillator layer  110 . 
         [0142]    As another case, the ratio of the fluorescent particles  114  may be increased gradiently from the upper surface of the scintillator layer  110  to the lower surface of the scintillator layer  110 . This is because that it may be difficult for the second photoelectric conversion layer  135  disposed on the lower surface of the scintillator layer  110  to detect light  30  as the X-ray incident amount is smaller in the lower area of the scintillator layer  110  than in the upper area of the scintillator layer  110 . 
         [0143]    As still another case, as shown in  FIG. 23 , total reflective films  230  may be formed at inner sides of the light paths  115 . In this case, the total reflective films  230  are formed to increase light detection efficiency by minimizing light loss. 
         [0144]    As described above, according to the present invention, the total reflective films are disposed at inner sides of the light paths of the scintillator layer to minimize light loss, whereby light detection efficiency may be increased. 
         [0145]      FIGS. 24 and 25  are structural cross-sectional diagrams illustrating an X-ray detector according to the twelfth embodiment of the present invention. 
         [0146]    As shown in  FIGS. 24 and 25 , the X-ray detector may include a scintillator layer  110  and a photoelectric conversion module that includes first and second photoelectric converters  120  and  130 . 
         [0147]    As shown in  FIG. 24 , the scintillator layer  110  may be provided with total reflective films  250  disposed at both sides. The total reflective films  250  may have flat shaped surfaces. The total reflective films  250  are formed to block light loss at both sides of the scintillator layer  110  and inwardly reflect light to minimize light loss and increase light detection efficiency. 
         [0148]    Also, as shown in  FIG. 25 , the scintillator layer  110  may be provided with total reflective films  250  disposed at both sides. The total reflective films  250  may have concave surfaces toward inner sides of the scintillator layer  110 . This is because that light may be reflected uniformly toward the inner sides of the scintillator layer  110  to increase light detection efficiency. 
         [0149]    As described above, according to the present invention, the total reflective films are disposed at both sides of the scintillator layer to minimize light loss, whereby X-ray detection efficiency may be increased. 
         [0150]    As described above, according to the present invention, the following advantages may be obtained. 
         [0151]    According to the present invention, since the photoelectric converters are respectively disposed on the upper surface and the lower surface of the scintillator layer, detection efficiency of X-rays may be increased, whereby picture quality of an image may be improved. 
         [0152]    Also, according to the present invention, the thickness of the photoelectric converter disposed on the upper surface of the scintillator layer may be reduced to enable a slim size and miniaturization. 
         [0153]    Also, according to the present invention, the block layer is disposed between the photoelectric conversion layers adjacent to each other to improve picture quality of an image by using a small amount of X-rays, whereby an exposure rate may be minimized. 
         [0154]    Also, according to the present invention, the light paths are disposed in the scintillator layer or the total reflective films are disposed at both sides of the scintillator layer to minimize light loss, whereby X-ray detection efficiency may be increased. 
         [0155]    Also, according to the present invention, images acquired from the plurality of photoelectric converters are compared with each other to select an image of high quality, or images acquired from the plurality of photoelectric converters are overlapped with each other to acquire an image of high quality regardless of a defect of the photoelectric converters. 
         [0156]    Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.