JP2011043390A - Radiation detection device - Google Patents

Abstract

An X-ray detection apparatus is provided that can reduce the thermal influence of a X-ray detection panel from a circuit board and suppress the occurrence of image unevenness.
An X-ray detection panel is supported on one surface of a support member, a circuit board is supported on the other surface of the support member, and these are accommodated in a casing. On the inner surface of the casing 16 facing the circuit board 14, a heat conducting portion 57 that protrudes toward the circuit board 14 is provided. The circuit board 14 and the heat conduction part 57 of the housing 16 are brought close to each other, the heat resistance of the heat conduction path from the circuit board 14 to the housing 16 is reduced, and more heat is conducted to the housing 16. The rate at which heat generated in the circuit board 14 is conducted to the X-ray detection panel 12 is reduced.
[Selection] Figure 1

Description

  The present invention relates to a radiation detection apparatus that detects radiation.

  2. Description of the Related Art Conventionally, X-ray detectors that detect radiation, particularly X-rays, are used in a wide range of fields such as industrial non-destructive inspection, medical diagnosis, and structural research.

  Among X-ray detection devices, as a highly sensitive and sharp device, an X-ray is formed on a photodetector having a photoelectric conversion element portion in which a plurality of photosensors and TFTs (Thin Film Transistors) are two-dimensionally arranged. There is known an X-ray detection apparatus including an X-ray detection panel in which a phosphor layer that directly converts light into light that can be detected by a photoelectric conversion element portion is formed.

  The X-ray detection panel is supported on one surface of a plate-shaped support member, and an integrated circuit for controlling the X-ray detection panel, processing signals from the X-ray detection panel, communicating with the outside, etc. is provided on the other surface of the support member. The mounted circuit board is supported, and the X-ray detection panel and the circuit board are electrically connected by a flexible circuit board.

  In such an X-ray detection apparatus, since the X-ray detection panel and the like dislike dust and humidity, a completely sealed structure in which the X-ray detection panel and the like are housed in a casing and completely isolated from the outside is adopted. .

  When the X-ray detector is activated, heat is generated from the integrated circuit on the circuit board, and a part of the generated heat is dissipated into the air inside the housing. The temperature distribution is created inside and outside the housing while creating a temperature difference due to thermal resistance.

  Accordingly, the heat generated from the circuit board flows into the support member that supports the circuit board. Further, the heat flowing into the support member flows into the X-ray detection panel having a lower temperature.

  Due to the heat transferred to the X-ray detection panel, the temperature of the X-ray detection panel rises and the operating temperature becomes high. The X-ray detection panel has a problem that when the operating temperature becomes high, the leakage current increases, the amount of noise change fluctuates, and image unevenness is caused.

  For such a problem, a method of cooling a circuit board with a cooling device has been proposed (see, for example, Patent Document 1). As a cooling device, there is a natural cooling type cooler, but a Peltier element, a cold water circulation device, or the like is used to obtain sufficient cooling performance.

  In addition, a method of energizing 24 hours before use so that the amount of change in leakage current is constant has also been proposed.

Japanese Patent Laying-Open No. 2005-283262 (page 6, FIG. 1-2)

  However, when a cooling device such as a Peltier device or a cold water circulation device is used to cool the circuit board, there is a problem that an extra system is required because the cooling device needs to be controlled.

  In addition, it is not practical to energize for 24 hours before use so that the amount of change in leakage current is constant, which is not easy on the environment, and it takes too much time to be used, which is not practical.

  In addition, a thermal conductive resin is provided on the integrated circuit of the circuit board, and the thermal conductive resin is thickened so as to be in contact with the casing so as to conduct heat to the casing, or the emissivity is reduced by using a thin thermal conductive resin. Although it can be considered that the heat is dissipated to the internal air of the case, there is a problem that the heat generated in the circuit board cannot be efficiently conducted to the case and dissipated to the case.

  The present invention has been made in view of the above points, and by efficiently conducting and dissipating heat generated in the circuit board to the housing, the radiation detection panel is thermally affected by the circuit board. An object of the present invention is to provide a radiation detection apparatus that can reduce the occurrence of image unevenness.

  The present invention relates to a radiation detection panel for detecting radiation, a support member for supporting the radiation detection panel on one surface, a circuit board supported on the other surface of the support member, and these radiation detection panel, support member and circuit substrate. And a housing in which an inner surface facing the circuit board is provided with a heat conduction portion protruding toward the circuit board.

  According to the present invention, by providing the heat conduction portion protruding toward the circuit board on the inner surface of the housing, the circuit board and the heat conduction portion of the housing are brought close to each other, and the heat conduction path from the circuit board to the housing The heat resistance can be reduced to dissipate more heat to the outside of the housing. Therefore, the ratio of heat conducted to the radiation detection panel among the heat generated in the circuit board can be reduced. Therefore, it is possible to reduce the increase in the operating temperature of the radiation detection panel due to the heat generated in the circuit board, and to suppress the occurrence of image unevenness.

1 is a cross-sectional view of a part of an X-ray detection apparatus as a radiation detection apparatus showing an embodiment of the present invention. It is sectional drawing of a part of X-ray detection panel of an X-ray detection apparatus same as the above.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  An X-ray detection device 11 as a radiation detection device includes an X-ray detection panel 12 as a radiation detection panel, a plate-like support member 13 that supports the X-ray detection panel 12 on one surface, and is supported on the other surface of the support member 13. A plurality of circuit boards 14, a flexible circuit board 15 that electrically connects the X-ray detection panel 12 and the circuit board 14, a housing 16 that accommodates them, and the like.

  As shown in FIG. 2, the X-ray detection panel 12 has a photodetector 21 as a photoelectric conversion substrate, and X-rays are detected on the incident side of X-rays as radiation in the photodetector 21. A phosphor layer 22 that converts light into detectable light is directly formed.

  The photodetector 21 has a glass substrate 23, and on the glass substrate 23, a plurality of photosensors and TFTs using CsI are two-dimensionally corresponding to a plurality of pixels arranged two-dimensionally. A photoelectric conversion element unit 24 that is disposed and converts light into an electric signal is formed. A wiring portion 25 connected to the photoelectric conversion element portion 24 is formed on the glass substrate 23, and a charge extraction portion (electrode pad portion) connected to the wiring portion 25 is provided on the outer peripheral portion of the glass substrate 23. 26 is formed.

  As shown in FIG. 1, the circuit board 14 has at least one of a control board (not shown) for controlling the X-ray detection panel 12 and an analog signal received from the flexible circuit board 15, processed and converted into a digital signal. An analog circuit board 31 having a function, a digital circuit board 32 having at least one function of control of other boards and communication with the outside of the X-ray detection device 11, and not shown for supplying power to the other boards A power supply circuit board and the like are provided.

  On the other surface of the analog circuit board 31 and the digital circuit board 32 on the opposite side to the support member 13, integrated circuits 34 and 35 are mounted as heat generating portions 33. Although not shown, an integrated circuit is mounted on the other surface of the control board as the heat generating portion 33, and an electrical component is mounted on the other surface of the power supply circuit board as the heat generating portion 33.

  The analog circuit board 31, the digital circuit board 32, the control board, and the power supply circuit board are supported in a state of being separated from the other surface of the support member 13 by a plurality of spacers 36.

  At least the analog circuit board 31 and the digital circuit board 32 have different support heights from the other surface of the support member 13, that is, one surface of the analog circuit board 31 is disposed on the other surface of the support member 13 via the spacer 36. One surface of the digital circuit board 32 is supported on the other surface of the analog circuit board 31 via a spacer 36.

  In addition, the flexible circuit board 15 includes a flexible board 41 and an IC mounting board 42 connected to one end of the flexible board 41, and an integrated circuit 43 for detection as a heat generating portion 33 is mounted on the IC mounting board 42. ing.

  The other end of the flexible substrate 41 is disposed on the charge extraction portion 26 of the X-ray detection panel 12 via an anisotropic conductive adhesive 44 and bonded by thermocompression bonding. A connector 45 is provided at one end of the IC mounting board 42, and the IC mounting board 42 is connected to the analog circuit board 31 by this connector 45.

  Between the support member 13 and one surface of the IC mounting substrate 42, a heat insulating member 46 that supports the IC mounting substrate 42 with respect to the support member 13 is interposed. The heat insulating member 46 is made of, for example, a fiber-based material having excellent heat insulating performance, and is bonded and fixed to the support member 13 and the IC mounting substrate 42 with an adhesive or a double-sided adhesive tape.

  In a state where the IC mounting substrate 42 is connected to the analog circuit substrate 31, the integrated circuit 43 is disposed on the other surface of the IC mounting substrate 42 that is opposite to the support member 13.

  The IC mounting board 42 is also configured as a part of the circuit board 14 supported on the other surface of the support member 13.

  The housing 16 has a box-shaped main body 51 having an opening on the X-ray incident surface side of the X-ray detection panel 12 and an opening 52 corresponding to the effective area of the X-ray detection panel 12. A frame-shaped cover portion 53 attached to the opening side of the portion 51 and an incident window 54 having X-ray transmissivity covering the opening portion 52 of the cover portion 53 are provided. The main body 51 and the cover 53 are made of a metal material that is excellent in heat conduction and heat dissipation.

  The main body 51 has a plate-like plate portion 55 facing the other surface of the support substrate 13 and each circuit board 14, and a frame portion 56 around the plate portion 55. A plurality of heat conducting portions 57 are provided on the inner surface of the plate portion 55 facing each circuit board 14 so as to protrude toward the heat generating portion 33 (integrated circuits 34, 35, 43, etc.) of each circuit board 14. It has been. Each heat conducting portion 57 has a different protruding height from the inner surface of the plate portion 55 depending on the supporting height of the heat generating portion 33 (integrated circuit 34, 35, 43, etc.) of each circuit board 14 with respect to the supporting member 13. Yes. Each heat conducting portion 57 may be formed integrally with the plate portion 55 (FIG. 1 shows an example formed integrally with the plate portion 55), or may be formed separately to conduct heat to the plate portion 55. It may be fixed to.

  Between each heat conducting portion 57 and the heat generating portion 33 (integrated circuits 34, 35, 43, etc.) of each circuit board 14, a heat conducting resin 58 is interposed to connect these heat conducting portions.

  Further, a cooling mechanism (not shown) such as a fan that dissipates heat transmitted to the casing 16 is disposed outside the casing 16.

  When the X-ray detection device 11 is activated, heat is generated from the heat generating portions 33 (integrated circuits 34, 35, 43, etc.) of each circuit board 14.

  A part of the heat generated from the heat generating portion 33 (integrated circuits 34, 35, 43, etc.) of each circuit board 14 is transferred to the air inside the housing 16, but most of the heat is transmitted to the circuit boards 14 and Heat conduction to the housing 16 through the heat conducting resin 58 on the heat generating part 33 (integrated circuit 34, 35, 43, etc.), moves to a lower temperature part, and creates a temperature difference due to thermal resistance. Create temperature distribution inside and outside of 16.

  Therefore, part of the heat generated from the heat generating portion 33 (integrated circuits 34, 35, 43, etc.) of each circuit board 14 flows into the support member 13 via the spacer 36 and the air layer.

  By the way, the heat conductive resin 58 on the heat generating portion 33 (integrated circuit 34, 35, 43, etc.) of each circuit board 14 has a lower thermal conductivity than a metal material. When the conductive portion 57 is not provided and the inner surface of the housing 16 and the heat generating portion 33 (integrated circuits 34, 35, 43, etc.) of each circuit board 14 are directly connected by the heat conductive resin 58, heat conduction The thickness of the resin 58 is increased, the thermal resistance to the casing 16 is large, and sufficient thermal conductivity to the casing 16 cannot be obtained.

  In the present embodiment, since each heat conducting portion 57 protrudes from the inner surface of the housing 16 and approaches the heat generating portion 33 (integrated circuit 34, 35, 43, etc.) of each circuit board 14, The ratio of the heat conductive resin 58 between the inner surface and the heat generating part 33 (integrated circuits 34, 35, 43, etc.) of each circuit board 14 is reduced, and the heat generating part 33 (integrated circuits 34, 35, 43, etc.) of each circuit board 14 is reduced. Etc.) to the housing 16 can be reduced, and high thermal conductivity to the housing 16 can be obtained.

  For this reason, the heat generated in the heat generating portion 33 (integrated circuits 34, 35, 43, etc.) of each circuit board 14 is efficiently conducted to the housing 16 and is transferred to the outside by a cooling mechanism provided outside the housing 16. And efficiently dissipate heat.

  The heat flowing into the support member 13 flows into the X-ray detection panel 12 at a lower temperature. Of the heat generated in the heat generating portion 33 (integrated circuits 34, 35, 43, etc.) of the circuit board 14, Since more heat is thermally conducted to the housing 16 and radiated, the rate of heat conduction to the support member 13 can be reduced, and the rate of heat conduction to the X-ray detection panel 12 can be reduced.

  Therefore, it is possible to reduce the increase in the operating temperature of the X-ray detection panel 12 due to the heat generated in the heat generating portion 33 (integrated circuits 34, 35, 43, etc.) of each circuit board 14, and to suppress the occurrence of image unevenness.

  Even when the support height for each circuit board 14 with respect to the support member 13 is different, the support height for each circuit board 14 is made different by making the protrusion height of each heat conducting portion 57 from the inner surface of the housing 16 different. Yes.

  Further, since the IC mounting substrate 42 is supported in a state separated from the other surface of the support member 13 by the heat insulating member 46, the amount of heat generated in the integrated circuit 43 flowing into the support member 13 can be suppressed.

11 X-ray detector as a radiation detector
12 X-ray detection panel as a radiation detection panel
13 Support member
14 Circuit board
16 housing
46 Thermal insulation
57 Heat conduction part

Claims (4)

A radiation detection panel for detecting radiation;
A support member for supporting the radiation detection panel on one surface;
A circuit board supported on the other surface of the support member;
The radiation detection panel, a support member, and a circuit board are accommodated, and a housing having a heat conduction portion protruding toward the circuit board on an inner surface facing the circuit board is provided. Radiation detection device. There are a plurality of the circuit boards, and the plurality of circuit boards have a plurality of types of support heights from the other surface of the support member,
The heat conduction portion is provided for each circuit board, and there are a plurality of types of protrusion heights from the inner surface of the housing according to the support height for each circuit board. The radiation detection apparatus described. 3. The radiation according to claim 1, wherein the heat conducting portion is formed integrally with the housing or is formed separately and attached to the housing. 4. Detection device. The radiation detection apparatus according to claim 1, further comprising a heat insulating member that supports the circuit board with respect to the support member between the support member and the circuit board.

Images