Radiation detector

Abstract

The technical problem to be solved by the present invention is to prevent the degradation of image quality and improve the detection accuracy of X-ray irradiation by maintaining the lightness of the radiation detector and effectively suppressing vibration. The radiation detector (100) comprises: a radiation detection unit (2), which has a flexible substrate (21) and a semiconductor element (23) formed on the imaging surface (22) of the substrate; a support component (4), which supports the radiation detection unit; a frame (front part (1), back part (8)), which accommodates the radiation detection unit; and a buffer component (C11-C13, C21-C23, C31-C33). The buffer component is arranged between the support component and the radiation detection unit, or between the support component and the back part (8) at least one of the two.

Description

Technical Field

[0001] The present invention relates to radiation detectors. Background Art

[0002] Conventionally, a thin and lightweight radiation detector called a flat panel detector (FPD) has been used to capture radiation (hereinafter also referred to as X-ray) images.

[0003] The market still expects further weight reduction of FPD. Among the parts constituting FPD, there are glass substrates and resin bases with a high weight ratio. The weight reduction of these parts is related to the weight reduction of FPD. In order to achieve weight reduction, TFT (thin film transistor) is formed on a film-like flexible substrate thinner than the glass substrate to reduce the weight of the glass part. A technology has been established in which a base is formed by using a lighter material, namely a foaming agent, and is formed by resin molding, so that it is in a state that can achieve further weight reduction compared with previous FPDs.

[0004] Patent document 1 describes a technology for installing conductive rubber supported on the surface opposite to the top plate of an electronic darkroom frame on the surface of a radiation detector mounted on the top plate of the frame, the surface being opposite to the surface mounted on the top plate, in order to prevent electrification caused by vibration when transporting the radiation detector.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: (Japanese) Patent Publication No. 2012-048169 Summary of the invention

[0008] Technical problem to be solved by the invention

[0009] Compared with the conventional TFT structure using a glass substrate, the TFT structure using a flexible substrate is lightweight but has lower rigidity and weaker vibration resistance. Therefore, if the distance between the signal line of the TFT and the base changes due to vibration, the parasitic capacitance formed in the space changes. In addition, noise is superimposed on the X-ray detection unit that detects images or X-ray radiation, resulting in deterioration of image quality and false detection of X-ray radiation.

[0010] The technical problem to be solved by the present invention is to prevent the degradation of image quality and improve the detection accuracy of X-ray irradiation by maintaining the lightness of the radiation detector and effectively suppressing vibration.

[0011] Technical solutions for solving technical problems

[0012] In order to solve the above technical problems, the radiation detector of the present invention has:

[0013] A radiation detection unit having a flexible substrate and a semiconductor element formed on an imaging surface of the substrate;

[0014] A supporting member, which supports the radiation detection unit;

[0015] a frame body including a front portion facing the imaging surface and a back portion facing the front portion across the radiation detection unit and accommodating the radiation detection unit;

[0016] A buffer member is provided at least one of between the support member and the radiation detection unit or between the support member and the back surface unit.

[0017] Effects of the Invention

[0018] According to the present invention, it is possible to prevent degradation of image quality and improve the detection accuracy of X-ray irradiation by maintaining the lightness of the radiation detector and effectively suppressing vibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic cross-sectional view of a radiation detector according to an embodiment of the present invention.

[0020] Figure 2 This is a perspective view viewed from the back side in order to show the stacked structure of the circuit board and its upper and lower buffer members and the supporting member.

[0021] Description of Reference Numerals

[0022] C11-C13, C21-C23, C31-C33 buffer components;

[0023] 1 front part;

[0024] 2. X-ray detection department;

[0025] 3. Radiation shielding components;

[0026] 4 Supporting components (base);

[0027] 5. Circuit board (reading circuit);

[0028] 6 interface substrate;

[0029] 7. Control substrate;

[0030] 8 dorsal face;

[0031] 9 Flexible printed substrate;

[0032] 100 X-ray detectors. DETAILED DESCRIPTION

[0033] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the scope of the present invention is not limited to the scope described in the following embodiments and drawings.

[0034] like Figure 1 As shown, a radiation detector 100 according to an embodiment of the present invention includes a front portion 1 of a housing, a radiation detection portion (a TFT of a flexible substrate) 2, a radiation shielding member 3, a support member (a base) 4, a circuit substrate 5, an interface substrate 6, a control substrate 7, a rear portion 8 of a housing, and a flexible printed substrate 9. It should be noted that a buffer material is provided between the front portion 1 and the radiation detection portion 2.

[0035] The radiation detector 100 is shown in the figure with the lateral direction being X, the longitudinal direction being Y, and the front-rear direction being Z.

[0036] like Figure 1 As shown, in the Z direction, the front portion 1, the radiation detection portion 2, the radiation shielding member 3, the support member 4, the circuit board 5 (the interface board 6, the control board 7), and the back portion 8 are stacked.

[0037] A reading circuit for reading a signal from the radiation detection unit is provided on the circuit substrate 5. The radiation detection unit 2 and the circuit substrate 5 are connected via a flexible printed substrate 9. The flexible printed substrate 9 is printed with a connection conductor pattern between the radiation detection unit 2 and the circuit substrate 5, and is bent around the Y axis from the radiation detection unit 2 to the circuit substrate 5.

[0038] The radiation detection unit 2 has a flexible substrate 21 and a semiconductor element 23 formed on the imaging surface 22 of the substrate 21. The radiation detection unit 2 has a plurality of radiation detection elements, which are arranged in a two-dimensional shape on the XY plane and are used to detect radiation. The radiation detection element is a semiconductor element such as a photodiode, a phototransistor, etc. The radiation detection element generates an electric charge corresponding to the amount of radiation irradiated. The switching element composed of TFT (thin film transistor) is connected one-to-one to the radiation detection element and is also arranged in a two-dimensional shape on the XY plane. Through the timing control of the on / off of the switching element, the detection analog signals of each column of the radiation detection elements in the Y direction are sent to each reading circuit on the circuit substrate 5 through the signal line extending in the Y direction.

[0039] An analog signal value is generated based on the amount of charge input from the signal line corresponding to each reading circuit.

[0040] The analog signal values ​​output from each reading circuit are sequentially sent to the interface substrate 6. The interface substrate 6 processes the signal from the circuit substrate 5. The interface substrate 6 converts the analog signal value from the circuit substrate 5 into a predetermined digital signal value and sends it to the control substrate 7.

[0041] The control circuit mounted on the control board 7 controls radiographic imaging and generates image data of radiographic images based on the signal value read by the reading circuit of the circuit board 5 and A / D converted by the interface board 6. That is, the control circuit has a function of generating image data based on the signal from the radiation detection unit 2.

[0042] Furthermore, the control circuit has a function of detecting the radiation exposure status based on the signal from the radiation detection unit 2 in order to control the radiographic imaging. The control circuit has a function of detecting the radiation exposure status based on the signal from the radiation detection unit 2 in synchronization with the moment when the radiation is irradiated from the radiation generating device arranged opposite to the radiation detection unit 2 across the subject to the radiation detection unit 2. It should be noted that the element for detecting the radiation exposure status may be provided separately from the radiation detection element for generating image data.

[0043] The flexible substrate of the radiation detection unit 2 is formed of a resin film. The radiation detection unit 2 may include a scintillator on the layer including the semiconductor element 23 including the radiation detection element and TFT.

[0044] The support member 4 is formed into a plate shape using a foam body, and supports the radiation detection unit 2 in a planar fixed shape.

[0045] The housing includes a front portion 1 facing the imaging surface 22 and a rear portion 8 facing the front portion 1 with the radiation detection unit 2 interposed therebetween, and houses the radiation detection unit 2 .

[0046] The radiation shielding member 3 is made of a sheet of lead, molybdenum, or tungsten, for example.

[0047] As in the present embodiment, the structure of the TFT using a flexible substrate and the foam base is lighter than the structure of the TFT using a glass substrate and the resin base in the past, but has lower rigidity and weaker vibration resistance. Therefore, if the distance between the signal line of the TFT and the base changes due to vibration, the parasitic capacitance formed in the space changes. Therefore, noise is superimposed on the image or X-ray detection unit, resulting in degradation of image quality and erroneous detection of the above-mentioned X-ray irradiation.

[0048] According to the research of the inventor of the present invention, in the structure of TFT and foam base using a flexible substrate, in order to reduce the influence of noise on the detection signal for detecting X-ray irradiation and improve the detection accuracy, it is effective to suppress the vibration of the connection point B between the flexible printed substrate 9 extending from the radiation detection part 2 to the circuit substrate 5 with a reading circuit and the radiation detection part 2.

[0049] For example, if a large impact is applied from the front portion 1, the connection portion B vibrates and generates noise.

[0050] Then, the vibration is transmitted to the circuit board 5 , the interface board 6 , and the flexible printed board 9 on the back surface 8 side through the support member 4 , and the connection part B is vibrated in a circular manner, resulting in the generation of noise.

[0051] In order to suppress vibration, the radiation detector 100 of this embodiment includes all or part of the buffer components C11, C12, C21, C22, C31, and C32. The buffer components C11 and C12 are in the same layer. When both are provided, the buffer component C13 between them may be included to form a continuous buffer component. The buffer components C21 and C22 are in the same layer. When both are provided, the buffer component C23 between them may be included to form a continuous buffer component. The buffer components C31 and C32 are in the same layer. When both are provided, the buffer component C33 between them may be included to form a continuous buffer component. The buffer components may be further extended to other ranges.

[0052] The buffer members C11 to C13 are provided between the support member 4 and the radiation detection unit 2 .

[0053] The buffer components C21-C23 and C31-C33 are disposed between the support component 4 and the back surface portion 8. The buffer components C21-C23 are disposed between the support component 4 and the circuit substrate 5 / interface substrate 6. The buffer components C31-C33 are disposed between the circuit substrate 5 / interface substrate 6 and the back surface portion 8.

[0054] The buffer member is provided at least one of between the support member 4 and the radiation detection unit 2 and between the support member 4 and the back surface unit 8 .

[0055] Furthermore, a buffer member may be provided between the support member 4 and the radiation detection unit 2 and between the support member 4 and the back surface portion 8. Vibration can be further suppressed.

[0056] The radiation shielding member 3 is provided between the radiation detection unit 2 and the supporting member 4 .

[0057] The buffer components C11-C13 are provided between the radiation shielding component 3 and the supporting component 4. When the buffer components arranged in the layer are limited to the buffer components C11-C13 for lightness, there are cases where they are limited to one or both of the buffer components C11 and C12. Even in these cases, due to the intervention of the radiation shielding component 3, the locally arranged buffer components will not directly contact the radiation detection unit 2. Thus, the local deformation of the radiation detection unit 2 can be suppressed, and the occurrence of image unevenness caused by this can be suppressed.

[0058] exist Figure 22 is a perspective view for illustrating the stacked structure of the circuit board 5 and its upper and lower buffer members, and the support member 4.

[0059] In order to effectively suppress vibration, a buffer member, like the buffer member C21 , is preferably provided between the support member 4 and the circuit board 5 at a position overlapping with at least the circuit board 5 when viewed in the Z direction.

[0060] In addition, like the buffer member C22 , it is preferable that a buffer member is provided between the support member 4 and the interface substrate 6 .

[0061] Furthermore, like the buffer member C31 , it is preferable that the buffer member be provided between the circuit board 5 and the back surface portion 8 at a position overlapping at least the circuit board 5 when viewed in the Z direction.

[0062] In addition, as shown by the buffer member C32 , it is preferable that a buffer member is provided between the interface substrate 6 and the back surface portion 8 .

[0063] In order to significantly maintain lightness and effectively suppress vibration to improve detection accuracy, it is preferred to implement a configuration limited to the buffer member C11 or a configuration limited to the buffer member C21. By effectively suppressing vibration of the connection part B, the influence of noise on the detection signal can be reduced, thereby improving detection accuracy.

[0064] The cushioning members C11 to C13 , C21 to C23 , and C31 to C33 can be rigid bodies such as plates molded from polycarbonate, ABS resin, carbon fiber reinforced resin, or foamed metal.

[0065] Furthermore, the cushioning members C11 to C13 , C21 to C23 , and C31 to C33 can be made of an elastomer such as ethylene propylene, chloroprene, polyethylene-based, olefin-based, or polyurethane-based elastomer.

[0066] Furthermore, the cushioning members C11 to C13 , C21 to C23 , and C31 to C33 can be foamed bodies such as polyethylene, polypropylene, and polystyrene.

[0067] In particular, by making the buffer members C11 to C13 rigid, they can function as spacers for maintaining the distance between the radiation shielding member 3 and the supporting member 4 , thereby suppressing changes in parasitic capacitance.

[0068] As described above, according to the radiation detector 100 of this embodiment, by adopting the TFT (2) and the foam base (4) of the lightweight flexible substrate and arranging the buffer components at appropriate positions, it is possible to effectively suppress the vibration that affects the detection accuracy. Therefore, by ensuring the lightweight of the radiation detector 100 and effectively suppressing the vibration, it is possible to prevent the degradation of the image quality and improve the detection accuracy of X-ray irradiation.

Claims

1. A radiation detector, characterized in that: have: A radiation detection unit having a flexible substrate and a semiconductor element formed on an imaging surface of the substrate; A supporting member, which supports the radiation detection unit; a frame body including a front portion facing the imaging surface and a back portion facing the front portion across the radiation detection unit and accommodating the radiation detection unit; A buffer member for suppressing vibration is provided at least one of between the support member and the radiation detection unit and between the support member and the back surface unit.

2. The radiation detector according to claim 1, characterized in that: The supporting member is formed of a foamed body.

3. The radiation detector according to claim 1 or 2, characterized in that: The buffer member is provided between the support member and the radiation detection unit, and between the support member and the back surface unit.

4. The radiation detector according to claim 1 or 2, characterized in that: A radiation shielding member is provided, the radiation shielding member is provided between the radiation detection unit and the support member, The buffer member is provided between the radiation shielding member and the supporting member.

5. The radiation detector according to claim 1 or 2, characterized in that: The device further comprises a circuit board provided with a reading circuit for reading a signal from the radiation detection unit. The buffer member is provided between the support member and the circuit board at a position overlapping at least the circuit board.

6. The radiation detector according to claim 5, characterized in that: further comprising an interface substrate for processing a signal from the circuit substrate, The buffer member is provided between the support member and the interface substrate.

7. The radiation detector according to claim 1 or 2, characterized in that: The device further comprises a circuit board provided with a reading circuit for reading a signal from the radiation detection unit. The buffer member is provided between the circuit substrate and the rear surface portion at a position overlapping at least the circuit substrate.

8. The radiation detector according to claim 7, characterized in that: further comprising an interface substrate for processing a signal from the circuit substrate, The buffer member is provided between the interface substrate and the back surface portion.

9. The radiation detector according to claim 5, characterized in that: The radiation detection unit and the circuit substrate are connected via a flexible printed substrate.

10. The radiation detector according to claim 1 or 2, characterized in that: The device has a function of generating image data based on the signal from the radiation detection unit and a function of detecting radiation exposure conditions.

11. The radiation detector according to claim 1 or 2, characterized in that: The buffer component is a rigid body.

12. The radiation detector according to claim 1 or 2, characterized in that: The buffer component is an elastic body.

13. The radiation detector according to claim 1 or 2, characterized in that: The cushioning member is a foam.

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