JP2011221042A - Image detecting device and image capturing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image detecting device and an image capturing system capable of adjusting uniformly and efficiently a temperature distribution of an image detection part.SOLUTION: A cooling panel 130 is arranged on an irradiation surface of a radiation X or a rear surface of a sensor substrate 38. A carbon nanotube 262 extending along the arrow D direction is formed in a carbon sheet 250 constituting the cooling panel 130, and each of heat radiation members 252 is connected to each end in the arrow D1 direction and in the arrow D2 direction of the carbon nanotube 262. As a result, heat from the sensor substrate 38 is transferred to each of the heat radiation members 252 through the carbon nanotube 262, and is discharged to the outside from each of the heat radiation members 252.

Description

  The present invention relates to an image detector that outputs an image recorded in a predetermined recording area as image information, and an image capturing system to which the image detector is applied.

  For example, in the medical field, image capturing apparatuses that acquire radiation image information by irradiating a subject (patient) with radiation from a radiation source and detecting radiation transmitted through the subject with an image detector are widely used. .

  In Patent Document 1, a base substrate is bonded to a back surface of an active matrix substrate on which a detection unit is mounted via a gel sheet, the gel sheet is formed of a viscoelastic body having thermal conductivity, and the base substrate is thermally conductive. It has been proposed to suppress variation in the temperature distribution of the active matrix substrate by using a material having good properties.

JP 2001-281343 A

  As described above, in Patent Document 1, it is possible to suppress variation in temperature distribution of the active matrix substrate by supporting the active matrix substrate via the gel sheet. On the other hand, it is expected that variations (non-uniformity) in temperature distribution will occur in the detection unit (image detection unit) arranged on the active matrix substrate. However, Patent Document 1 does not describe any measures for quickly removing uneven temperature distribution in the detection unit.

  Further, Patent Document 1 merely discloses that the active matrix substrate and the base substrate are bonded together by a gel sheet, and how to improve the heat conduction characteristics of the gel sheet to dissipate the heat of the active matrix substrate. It is not disclosed at all about the point.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an image detector and an image capturing system that can adjust the temperature distribution of an image detection unit uniformly and efficiently.

  To achieve the above object, the present invention records a predetermined image, outputs the recorded image as image information, and is arranged on the surface of the image detection unit and includes the image detection unit. A cooling panel for cooling, the cooling panel having a heat conduction characteristic for transferring heat of the image detection unit, and further comprising a heat radiating member for releasing heat transferred from the image detection unit to the outside. The heat conduction characteristic is directed to a surface direction along a surface of the image detection unit and to a disposition direction of the heat radiating member.

  According to the present invention, since the cooling panel is arranged on the surface of the image detection unit, the heat from the image detection unit is along the surface direction of the image detection unit toward which the heat conduction characteristic of the cooling panel is directed. It is transmitted to the heat radiating member and radiated to the outside. As a result, compared to the prior art, the heat dissipation efficiency of the entire image detector is improved, it is possible to ensure the uniformity of the temperature distribution of the image detection unit, and the temperature distribution is adjusted efficiently. can do.

1 is a configuration block diagram of an image capturing system according to the present embodiment. FIG. 2A is a schematic configuration perspective view in which a cooling panel is disposed on the back side of the sensor substrate in the radiation solid detector of FIG. 1, and FIG. 2B is a diagram illustrating cooling on the irradiation surface side of the sensor substrate in the radiation solid detector. It is a schematic structure perspective view which has arrange | positioned the panel. It is a typical perspective view which shows the internal structure of the carbon sheet of FIG. 2A and 2B. 4A is a schematic cross-sectional view of the cooling panel of FIG. 2A, and FIG. 4B is a schematic cross-sectional view of the cooling panel of FIG. 2B. It is a circuit block diagram of the radiation solid state detector shown in FIG. FIG. 6 is a detailed block diagram of the signal readout circuit shown in FIG. 5. It is a perspective view at the time of applying the image photographing system of FIG. 1 to a mammography apparatus. It is principal part explanatory drawing which shows the internal structure of the imaging stand of FIG. It is a schematic block diagram which shows the other structure of a radiation solid state detector.

  FIG. 1 is a configuration block diagram of an image capturing system 20 according to the present embodiment.

  The imaging system 20 includes a radiation generator 24 that generates radiation X and irradiates the subject 22, a radiation solid detector (image detector, radiation image information detector) 26 that detects the radiation X transmitted through the subject 22, and The control unit 28 for controlling the radiation generator 24 and the radiation solid detector 26, the console 30 for setting the imaging conditions such as the irradiation dose of the radiation X to the subject 22 in the control device 28, and the radiation solid detector 26 are read out. An image processing device 32 that performs predetermined image processing on the radiation image information of the subject 22 and a display device 34 that displays the processed radiation image information are provided.

  The radiation solid detector 26 includes a sensor substrate (image detection unit) 38, a gate line driving circuit 44, a battery 45, a signal readout circuit 46, a timing control circuit 48, a temperature control unit 135, and a communication unit 136. Further, the temperature control unit 135 includes a cooling panel 130, a temperature controller 133, a temperature sensor 138, and a fan (cooling fan) 140.

  2A and 2B are schematic configuration perspective views of the radiation solid state detector 26. FIG. The radiation solid detector 26 is housed in a protective case 36 and stores (records) radiation image information related to the radiation X transmitted through the subject 22 (see FIG. 1) as two-dimensional charge information, and this sensor. The cooling panel 130 closely arranged on the one surface side (irradiation surface side) irradiated with the radiation X with respect to the board | substrate 38 or its back surface side is provided.

  That is, FIG. 2A shows the case where the cooling panel 130 is disposed on substantially the entire back side of the sensor substrate 38, while FIG. 2B shows the case where the cooling panel 130 is disposed on substantially the entire irradiation surface side of the sensor substrate 38. It is.

  Here, the cooling panel 130 includes a heat conductive carbon sheet 250 disposed on the irradiation surface or the back surface of the sensor substrate 38, and an end of the carbon sheet 250 on the arrow D direction side (in the arrow D1 direction and the arrow D2 direction). And a block-shaped heat dissipating member 252 connected to each end portion. The arrow D direction refers to the short direction of the sensor substrate 38 among the directions (plane directions) along the irradiation surface and the back surface of the sensor substrate 38.

  The carbon sheet 250 is disposed on the irradiation surface or the back surface of the sensor substrate 38 with the end portions in the arrow D direction (the arrow D1 direction and the arrow D2 direction) protruding from the sensor substrate 38. On the other hand, each heat radiating member 252 is connected to each end portion of the carbon sheet 250 protruding from the sensor substrate 38 in a state of being separated from each side surface of the sensor substrate 38 in the arrow D1 direction and the arrow D2 direction.

  FIG. 3 is a schematic perspective view for explaining the internal configuration of the carbon sheet 250. In the carbon sheet 250, a mesostructured film in which a plurality of tubular pores 260 penetrating in the direction of arrow D is arranged is formed, and in each pore 260 constituting the mesostructured film, a carbon nanotube 262 is formed. Extends along the direction of arrow D. Therefore, the carbon sheet 250 is a carbon sheet whose heat conduction characteristics are directed in the direction of arrow D. Note that the mesostructured film including the pores 260 and the carbon nanotubes 262 is formed using, for example, a technique disclosed in Japanese Patent Application Laid-Open No. 2007-105859.

  As shown in the schematic cross-sectional views of the cooling panel 130 in FIGS. 4A and 4B, the heat radiating member 252 is connected to the ends (tip portions) of the carbon nanotubes 262 in the arrow D1 direction and the arrow D2 direction. Therefore, the heat of the sensor substrate 38 is transmitted to the heat radiating member 252 via the carbon nanotubes 262 of the carbon sheet 250 and is radiated to the outside from the heat radiating member 252.

  4B, when the cooling panel 130 is disposed on the irradiation surface side of the sensor substrate 38, the carbon sheet 250 and the heat radiating member 252 constituting the cooling panel 130 are made of a material that can transmit the radiation X. Has been.

  FIG. 5 is a circuit configuration block diagram of the radiation solid state detector 26. The radiation solid detector 26 includes a sensor substrate 38, a gate line driving circuit 44 including a plurality of driving ICs (not shown), a signal reading circuit 46 including a plurality of reading ICs 42 (see FIG. 6), and a gate line driving circuit. 44 and a timing control circuit 48 for controlling the signal readout circuit 46.

  The sensor substrate 38 includes a matrix-shaped thin film transistor including a photoelectric conversion layer 51 made of a substance such as amorphous selenium (a-Se) that senses radiation X (see FIGS. 1 to 2B, 4A, and 4B) and generates charges. (TFT: Thin Film Transistor) 52 has a structure arranged on an array, and after the generated charge is accumulated in the storage capacitor 53, the TFT 52 is sequentially turned on for each row, and the charge is read out as an image signal. In FIG. 5, only the connection relationship between one pixel 50 including the photoelectric conversion layer 51 and the storage capacitor 53 and one TFT 52 is shown, and the configuration of the other pixels 50 is omitted. Amorphous selenium must be used within a predetermined temperature range because its structure changes and its function decreases at high temperatures. A gate line 54 extending parallel to the row direction and a signal line 56 extending parallel to the column direction are connected to the TFT 52 connected to each pixel 50. Each gate line 54 is connected to the gate line drive circuit 44, and each signal line 56 is connected to the signal readout circuit 46.

  FIG. 6 is a detailed block diagram of the signal readout circuit 46. The signal readout circuit 46 is based on a readout IC 42 connected to each signal line 56 of the sensor substrate 38 (see FIGS. 1 to 2B and FIGS. 4A to 5) and a timing control signal from the timing control circuit 48. A multiplexer 60 that selects a pixel 50 connected to one of the lines 56, and radiographic image information read from the selected pixel 50 is converted into an image signal as a digital signal, and the image processing apparatus 136 via the communication unit 136 And an A / D converter 62 that transmits (outputs) the data to / from 32.

  The reading IC 42 includes an operational amplifier 66 (integration amplifier) that detects a current supplied from the signal line 56 via the resistor 64, an integration capacitor 68, and a switch 70. A signal line 56 is connected to the inverting input terminal of the operational amplifier 66 through the resistor 64, and the reference voltage Vb is supplied to the non-inverting input terminal of the operational amplifier 66.

  As described above, the photoelectric conversion layer 51 (see FIG. 5) constituting the sensor substrate 38 is made of amorphous selenium, and the amorphous selenium changes its structure and deteriorates its function at a high temperature. Must be used within the temperature range. Therefore, the radiation solid detector 26 cools the sensor substrate 38 when the temperature of the photoelectric conversion layer 51 (amorphous selenium) exceeds the temperature range, and maintains the temperature of the photoelectric conversion layer 51 within the temperature range. Temperature control means 135 (see FIG. 1).

  That is, the temperature sensor 138 that constitutes the temperature control means 135 is disposed in the vicinity of the sensor substrate 38, detects the temperature of the sensor substrate 38 according to the temperature of amorphous selenium constantly or at predetermined time intervals, and detects the detected sensor substrate 38. Is output to the temperature controller 133. The temperature controller 133 determines whether or not the input temperature of the sensor substrate 38 exceeds a predetermined upper limit temperature corresponding to the upper limit value of the temperature range of the photoelectric conversion layer 51 (amorphous selenium). Here, the temperature controller 133 drives the fan 140 when it is determined that the temperature of the sensor substrate 38 exceeds the upper limit temperature. The fan 140 blows air to the heat radiating member 252 and cools the heat radiating member 252 so that heat radiation at the heat radiating member 252 is promoted.

  Note that the above-described upper limit temperature is registered in advance in the temperature controller 133, or is registered in advance in the control device 28 as part of the imaging conditions, and the communication device 136 from the control device 28 before the radiographic image is captured. May be transmitted to the temperature controller 133 via

  The image capturing system 20 of the present embodiment is basically configured as described above, and the operation thereof will be described next with reference to FIGS.

  First, using the console 30, ID information related to the subject 22, shooting conditions, and the like are set. In this case, the ID information includes information such as the name, age, and sex of the subject 22, and can be acquired from an ID card possessed by the subject 22. Further, as imaging conditions, in addition to information such as an imaging region and an imaging direction instructed by a doctor, an irradiation dose of radiation X corresponding to the imaging region and, if necessary, an upper limit value of the temperature range of amorphous selenium. There is a corresponding upper limit temperature of the sensor board 38, which can be acquired from a higher-level device connected to the network, or can be input from the console 30 by a radiologist.

  Next, after positioning the imaging region of the subject 22 with respect to the radiation solid detector 26, the control device 28 controls the radiation generator 24 and the radiation solid detector 26 according to the set imaging conditions.

  In this case, the temperature sensor 138 detects the temperature of the sensor substrate 38 according to the temperature of amorphous selenium at all times or at predetermined time intervals, and outputs the detected temperature of the sensor substrate 38 to the temperature controller 133. Each time the temperature of the sensor substrate 38 is input from the temperature sensor 138 or at a predetermined time interval, the temperature controller 133 adjusts the temperature of the sensor substrate 38 according to the upper limit value of the temperature range of the amorphous selenium. It is determined whether or not the upper limit temperature is exceeded.

  On the other hand, the radiation generator 24 irradiates the subject 22 with the radiation X based on the imaging conditions transmitted from the controller 28. The radiation X that has passed through the subject 22 is converted into an electrical signal by the photoelectric conversion layer 51 of each pixel 50 on the sensor substrate 38 of the radiation solid state detector 26, and is stored as a charge in the storage capacitor 53 (see FIG. 5). Next, the charge information that is the radiographic image information of the subject 22 stored in each storage capacitor 53 is read according to the timing control signal supplied from the timing control circuit 48 to the gate line driving circuit 44 and the signal reading circuit 46.

  That is, the gate line driving circuit 44 selects one of the gate lines 54 in accordance with the timing control signal from the timing control circuit 48 and supplies a driving signal to the base of each TFT 52 connected to the selected gate line 54. . On the other hand, in accordance with the timing control signal from the timing control circuit 48, the signal readout circuit 46 selects the signal line 56 connected to the readout IC 42 by the multiplexer 60 while sequentially switching in the row direction. The charge information related to the radiation image information stored in the storage capacitor 53 of the pixel 50 corresponding to the selected gate line 54 and signal line 56 is supplied to the operational amplifier 66 via the resistor 64 and integrated, and then the multiplexer. The image signal is supplied to the A / D converter 62 through 60 and supplied to the image processing apparatus 32 through the communication means 136 as an image signal which is a digital signal. After the image signal is read from each pixel 50 arranged in the row direction, the gate line drive circuit 44 selects the next gate line 54 in the column direction and supplies a drive signal, and the signal read circuit 46 Similarly, an image signal is read from the TFT 52 connected to the selected gate line 54. By repeating the above operation, two-dimensional radiation image information accumulated in each pixel 50 in the sensor substrate 38 is read and supplied to the image processing device 32.

  The radiographic image information adjusted as described above and supplied to the image processing device 32 is displayed on the display device 34 for diagnosis or the like after being subjected to predetermined image processing. Therefore, the doctor can perform processing such as diagnosis based on the image displayed on the display device 34.

  Here, the heat of the amorphous selenium in the sensor substrate 38 is transmitted to the heat radiating member 252 through the carbon nanotubes 262 of the carbon sheet 250, and is radiated from the heat radiating member 252 to the outside of the cooling panel 130.

  As described above, the temperature controller 133 (see FIG. 1) is configured so that the amorphous selenium temperature (according to the temperature of the sensor substrate 38) is within the amorphous selenium temperature range (the upper limit temperature of the sensor substrate 38 according to the upper limit value). However, if it is determined that the temperature of the sensor substrate 38 exceeds the upper limit temperature, the fan 140 is driven. Thus, the fan 140 blows air to the heat radiating member 252 and cools the heat radiating member 252 so that heat radiating in the heat radiating member 252 is promoted.

  Further, when the temperature controller 133 determines that the temperature of the sensor substrate 38 detected by the temperature sensor 138 is lower than the upper limit temperature, the temperature controller 133 stops driving the fan 140.

  Thus, in the imaging system 20 according to the present embodiment, the radiation solid detector 26 has the cooling panel 130 disposed on the irradiation surface or the back surface of the sensor substrate 38, and the cooling panel 130 is the sensor substrate 38. Therefore, the heat of the amorphous selenium in the sensor substrate 38 is transferred along the arrow D direction in the cooling panel 130. Heat is dissipated to the outside. As a result, compared with the prior art, the radiation efficiency of the radiation solid state detector 26 as a whole is improved, it is possible to ensure the uniformity of the temperature distribution of the sensor substrate 38, and the temperature distribution is efficiently reduced. Can be adjusted.

  In addition, the cooling panel 130 is disposed on the irradiation surface or back surface of the sensor substrate 38 and has a carbon sheet 250 whose heat conduction characteristics are directed in the direction of arrow D, and an arrow D direction in the carbon sheet 250 (arrow D1 direction and arrow D2 direction). And a heat radiating member 252 that releases heat transferred from the sensor substrate 38 via the carbon sheet 250 to the outside. Accordingly, the cooling panel 130 has a simple configuration of the carbon sheet 250 and the heat radiating member 252, and the heat of the sensor substrate 38 is radiated without receiving any energy supply from the temperature controller 133. As a result, it is possible to efficiently ensure the uniformity and to adjust the temperature distribution, and to realize energy saving of the radiation solid state detector 26.

  Further, the carbon sheet 250 is composed of a plurality of carbon nanotubes 262 extending along the arrow D direction, and the heat radiating member 252 is connected to each tip portion of each carbon nanotube 262 along the arrow D1 direction and the arrow D2 direction. Therefore, the heat transferred from the sensor substrate 38 to the carbon nanotube 262 can be reliably and efficiently radiated from the heat radiation member 252 to the outside.

  Furthermore, when the irradiation surface or back surface of the sensor substrate 38 is rectangular in plan view, each carbon nanotube 262 extends along the arrow D direction which is the short direction of the irradiation surface or the back surface, Furthermore, since the heat radiating member 252 is disposed along the direction orthogonal to the arrow D direction (longitudinal direction of the sensor substrate 38), the discharge area of the heat transferred from the sensor substrate 38 to the carbon nanotube 262 is remarkably increased. As the distance increases, the heat conduction distance becomes shorter, and the heat can be radiated from the heat radiating member 252 to the outside more efficiently.

  Furthermore, the temperature sensor 138 of the temperature control means 135 detects the temperature of the sensor substrate 38 according to the temperature of amorphous selenium, and the temperature controller 133 detects the temperature of the detected sensor substrate 38 within the temperature range of the amorphous selenium. It is determined whether or not a predetermined upper limit temperature of the sensor substrate 38 corresponding to the upper limit value of the sensor substrate 38 is exceeded, and when it is determined that the temperature exceeds the predetermined upper limit temperature, the temperature of the sensor substrate 38 (the temperature of the amorphous selenium indicated) is The fan 140 is driven so as to decrease to an upper limit value of the temperature range shown). The fan 140 blows air to the heat radiating member 252 so that heat radiated from the sensor substrate 38 to the heat radiating member 252 through the carbon sheet 250 is promoted to the outside of the cooling panel 130. Thereby, the sensor substrate 38 can be efficiently cooled.

  Furthermore, when the cooling panel 130 is arranged on the irradiation surface of the sensor substrate 38, the cooling panel 130 is configured to be able to transmit the radiation X, so that the sensor substrate 38 can be irradiated regardless of the irradiation of the radiation X. The substrate 38 can be cooled.

  FIG. 7 is an explanatory perspective view when the image capturing system 20 according to the present embodiment is applied to a mammography apparatus 170 used for breast cancer screening or the like.

  The mammography apparatus 170 includes a base 172 installed in an upright state, an arm member 176 fixed to a turning shaft 174 disposed at a substantially central portion of the base 172, and a breast 179 that is an imaging region of the subject 22. A radiation source storage unit 180 that stores a radiation source (not shown) that irradiates radiation X with respect to (see FIG. 8) and is fixed to one end of an arm member 176, and an arm that is disposed opposite to the radiation source storage unit 180 An imaging table 182 fixed to the other end of the member 176 and a compression plate 184 that presses and holds the breast 179 against the imaging table 182 are provided.

  The arm member 176 to which the radiation source storage unit 180 and the imaging stand 182 are fixed is configured to be adjustable in the imaging direction with respect to the breast 179 of the subject 22 by rotating in the direction of arrow A about the rotation axis 174. The compression plate 184 is disposed between the radiation source storage unit 180 and the imaging table 182 while being connected to the arm member 176, and is configured to be displaceable in the arrow B direction.

  In addition, on the base 172, the imaging part of the subject 22 detected by the mammography apparatus 170, imaging information such as the imaging direction, ID information of the subject 22, and the like can be displayed, and these information can be set as necessary. A display operation unit 186 is provided. Therefore, the display operation unit 186 has some functions of the console 30 and the display device 34 (see FIG. 1) described above.

  FIG. 8 is a main part explanatory diagram showing an internal configuration of the imaging stand 182 in the mammography apparatus 170, and shows a state in which a breast (mammo) 179 that is an imaging region of the subject 22 is arranged between the imaging stand 182 and the compression plate 184. .

  In the imaging table 182, radiation image information captured based on the radiation X output from the radiation source built in the radiation source storage unit 180 is accumulated, and the radiation solid is output as an electrical signal (image signal). The detector 26 is accommodated. FIG. 8 illustrates a case where the cooling panel 130 is disposed on the irradiation surface side of the sensor substrate 38. Further, in order to avoid the influence of the heat radiation on the subject 22 by the heat radiation member 252, the heat radiation member 252 is arranged so as not to extend to the subject 22 side.

  7 and 8, the case where the cooling panel 130 is disposed on the irradiation side of the sensor substrate 38 has been described. However, even when the cooling panel 130 is disposed on the back side of the sensor substrate 38, the mammography apparatus 170 illustrated in FIGS. Good.

  Also in the mammography apparatus 170 described above, the effects of the present embodiment described above can be obtained by housing the radiation solid detector 26 in which the cooling panel 130 is disposed on the surface of the sensor substrate 38 in the imaging table 182.

  In FIG. 9, instead of the radiation solid state detector 26 using the TFT 52 shown in FIG. 5, the radiation image information is stored as an electrostatic latent image, and the electrostatic latent image is read out as charge information by irradiating the reading light L. The structure of the radiation solid state detector 190 using the sensor board | substrate 200 to be shown is shown.

  The sensor substrate 200 has a first electrode layer 204 that is transparent to the radiation X in order from the side irradiated with the radiation X (irradiation surface side), and recording that exhibits conductivity when irradiated with the radiation X. From the reading light source unit 210, the photoconductive layer 206 acts as a substantially insulator for the latent image charge, while acting as a substantially conductive material for the transport charge having the opposite polarity to the latent image charge. A reading photoconductive layer 212 that exhibits conductivity when irradiated with the reading light L and a second electrode layer 214 that is transmissive to the reading light L are provided.

  At the interface between the recording photoconductive layer 206 and the charge transport layer 208, a power storage unit 216 that accumulates the charges generated in the recording photoconductive layer 206 as latent image charges is formed. The second electrode layer 214 has a number of linear electrodes 218 extending in a direction (arrow C direction) orthogonal to the direction in which the reading light source unit 210 extends. A signal readout circuit 220 that reads out charge information related to the latent image charge accumulated in the power storage unit 216 is connected to the linear electrodes 218 constituting the first electrode layer 204 and the second electrode layer 214.

  The signal readout circuit 220 is connected to a power source 222 and a switch 224 that apply a predetermined voltage between the first electrode layer 204 and the second electrode layer 214 of the sensor substrate 200, and each linear electrode 218 of the second electrode layer 214. A current detection amplifier 226 that detects radiation image information as a latent image charge as a current, a resistor 230, a multiplexer 234 that sequentially switches the output from each current detection amplifier 226, and an analog that is an image signal output from the multiplexer 234 And an A / D converter 236 for converting the signal into a digital signal. The current detection amplifier 226 includes an operational amplifier 238, an integration capacitor 240, and a switch 242.

  Although FIG. 9 illustrates the case where the cooling panel 130 is disposed on the irradiation surface side of the sensor substrate 200, the cooling panel 130 may be disposed on the back side.

  In the sensor substrate 200 configured as described above, the switch 224 is connected to the power source 222 side, and the radiation X is applied to the subject 22 (with the predetermined voltage applied between the first electrode layer 204 and the second electrode layer 214. (See FIG. 1). The radiation X transmitted through the subject 22 is applied to the recording photoconductive layer 206 through the first electrode layer 204. At this time, the recording photoconductive layer 206 exhibits conductivity and generates charge pairs. Of the generated charge pair, the positive charge is combined with the negative charge supplied from the power source 222 to the first electrode layer 204 and disappears. On the other hand, the negative charge generated in the recording photoconductive layer 206 moves toward the charge transport layer 208. Since the charge transport layer 208 acts as a substantially insulator against negative charges, negative charges are accumulated as an electrostatic latent image in the power storage unit 216 that is an interface between the recording photoconductive layer 206 and the charge transport layer 208. .

  After the electrostatic latent image is recorded on the sensor substrate 200, the radiographic image information is read out by the signal reading circuit 220. In this case, the non-inverting terminal of the operational amplifier 238 constituting the current detection amplifier 226 is connected to the first electrode layer 204 of the sensor substrate 200 via the switch 224.

  While the reading light source 210 is moved in the sub-scanning direction (arrow C direction), the reading photoconductive layer 212 is irradiated with the reading light L, and the switch 242 of the current detection amplifier 226 is turned on / off according to a predetermined pixel pitch in the sub-scanning direction. By controlling the radiation image information, which is charge information related to the electrostatic latent image, is read out.

  When the reading light L is irradiated to the reading photoconductive layer 212 through the second electrode layer 214, the reading photoconductive layer 212 exhibits conductivity and a charge pair is generated. Among the generated charge pairs, the positive charge reaches the power storage unit 216 via the charge transport layer 208 that acts as a conductor for the positive charge, and is stored in the power storage unit 216. It disappears in combination with the negative charge that constitutes. On the other hand, the negative charge of the reading photoconductive layer 212 is recombined with the positive charge of the linear electrode 218 constituting the second electrode layer 214 and disappears. At this time, a current is generated in the linear electrode 218 along with the disappearance of the charge, and this current is read by the signal readout circuit 220 as the charge information related to the radiation image information.

  The current generated in each linear electrode 218 is integrated by the current detection amplifier 226 and supplied to the multiplexer 234 as a voltage signal. The multiplexer 234 sequentially switches the current detection amplifier 226 in the main scanning direction that is the arrangement direction of the linear electrodes 218, and supplies a voltage signal to the A / D converter 236. The A / D converter 236 converts the supplied image signal, which is an analog voltage signal, into a digital signal and outputs the digital signal to the image processing device 32 as radiation image information. Note that when the radiation image information for one pixel in the sub-scanning direction is read, the switch 242 of the current detection amplifier 226 is turned on, and the charge accumulated in the integration capacitor 240 is discharged. The radiation image information accumulated and recorded on the sensor substrate 200 is read two-dimensionally by repeating the above operation while moving the reading light source unit 210 in the direction of arrow C.

  Also in the image capturing system 20 including the radiation solid detector 190 described above, the cooling panel 130 is disposed on the surface of the sensor substrate 38, so that the effects of the present embodiment described above can be obtained.

  Of course, the image capturing system 20 according to the present embodiment is not limited to the above-described embodiment, and can be freely changed to various configurations.

  For example, instead of the radiation solid detectors 26 and 190 that directly convert the irradiated radiation X into charge information, the radiation X is converted into visible light once by a scintillator, and the visible light is converted into charge information. A detector can also be used.

  Further, at the time of recording radiation image information to each pixel 50 or reading out radiation image information, there is a concern that the driving of the fan 140 may be superimposed as noise on the radiation image information to deteriorate the image quality of the radiation image information. Is done. For such a problem, at the time of recording and / or at the time of reading, the operation of the temperature control means 135 is stopped to stop cooling the sensor substrate 38, while at the time of recording and / or at the time of reading. In other time zones, the temperature control means 135 may be operated to cool the sensor substrate 38.

  Furthermore, instead of cooling the heat dissipation member 252 by the fan 140, the heat dissipation member 252 may be cooled by, for example, a heat pipe, a heat conductive gel, or water cooling.

  Of course, the image detector and the image capturing system according to the present invention are not limited to the above-described embodiments, and various configurations can be adopted without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 20 ... Imaging system 22 ... Subject 24 ... Radiation generator 26, 190 ... Radiation solid state detector 38, 200 ... Sensor substrate 42 ... Reading IC
44 ... gate line driving circuit 46, 220 ... signal readout circuit 48 ... timing control circuit 50 ... pixel 51 ... photoelectric conversion layer 130 ... cooling panel 133 ... temperature controller 135 ... temperature control means 138 ... temperature sensor 140 ... fan 170 ... mammography Device 179 ... Breast 182 ... Imaging stand 250 ... Carbon sheet 252 ... Heat radiation member 260 ... Fine pore 262 ... Carbon nanotube

Claims (12)

An image detection unit for recording a predetermined image and outputting the recorded image as image information;
A cooling panel disposed on a surface of the image detection unit and cooling the image detection unit;
Have
The cooling panel has a heat conduction characteristic for transferring heat of the image detection unit, and further includes a heat dissipation member that releases heat transferred from the image detection unit to the outside.
The image detector according to claim 1, wherein the heat conduction characteristic is oriented in a surface direction along a surface of the image detection unit and in a disposing direction of the heat radiating member. The image detector according to claim 1.
Of the surface of the image detection unit, one surface on which the cooling panel is disposed is rectangular in plan view, and the cooling panel is oriented in the heat conduction characteristic along the short direction of the one surface. An image detector characterized by. The image detector according to claim 2.
The cooling panel has a rectangular shape in which the end in the longitudinal direction substantially coincides with the one surface, and the end in the short-side direction extends from the one surface,
The heat radiating member is connected to an end portion in a short direction. In the image detector as described in any one of Claims 1-3,
The image detector, wherein the cooling panel is a carbon sheet containing carbon. The image detector according to claim 4.
An image detector, wherein the cooling panel has a structure in which a plurality of tubular pores are arranged. The image detector according to claim 5.
The image detector according to claim 1, wherein the pores are penetrated toward the heat radiating member, and carbon nanotubes are disposed therein. The image detector according to any one of claims 1 to 6,
The image detector further comprising: a temperature sensor that detects a temperature of the image detection unit; and a cooling fan that blows air to the heat radiating member to cool the heat radiating member. In the image detector of any one of Claims 1-7,
The image detector is a radiation image information detector,
The image detection unit records radiation applied to one surface of the image detection unit through a subject as a radiation image, and outputs the recorded radiation image as radiation image information.
The cooling panel is disposed on one surface of the image detection unit as the radiation irradiation surface or on the back surface thereof,
When the cooling panel is disposed on the irradiation surface, the cooling panel is configured to transmit the radiation. The image detector according to claim 8.
The radiation image information detector is a radiation solid detector that accumulates the radiation transmitted through the subject as charge information and reads the accumulated charge information as the radiation image information. . The image detector according to claim 9.
The radiation solid-state detector is an optical readout type detector in which the accumulated charge information is read out as radiation image information when irradiated with readout light.   An image photographing system comprising: the image detector according to claim 1; and a control device that controls the image detector. The image capturing system according to claim 11,
A radiation generator for generating radiation and irradiating the subject;
The image detector records the radiation transmitted through the subject as a radiation image, and outputs the recorded radiation image to the outside as radiation image information,
The image capturing system, wherein the control device controls the radiation generating device and the image detector.

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